U.S. patent application number 10/051140 was filed with the patent office on 2004-02-12 for retractable needle single use safety syringe.
Invention is credited to Mahurkar, Sakharam D..
Application Number | 20040030294 10/051140 |
Document ID | / |
Family ID | 26729113 |
Filed Date | 2004-02-12 |
United States Patent
Application |
20040030294 |
Kind Code |
A1 |
Mahurkar, Sakharam D. |
February 12, 2004 |
Retractable needle single use safety syringe
Abstract
A safety syringe assembly includes an elongated, generally
cylindrical barrel having a hollow interior forming a hollow nozzle
located at a distal end of the barrel and opening into the interior
of the barrel. A plunger is slidably mounted in the barrel and has
a longitudinal open channel. A needle holder mounts a needle at a
distal end thereof and is slidably mounted in the longitudinal open
channel of the plunger for movement between an advanced position in
which the needle on the distal end of the needle holder projects
from a distal end of the nozzle, and a retracted position in which
the needle is retracted within the barrel. A compression spring is
mounted inside of the barrel, and a spring retainer element has a
spring support portion extending from the interiorly of the barrel
to a portion for mounted within the barrel and supporting a distal
end portion of the spring against expansion. The spring urges the
needle holder toward its retracted position. A latch has a closed
position in which the needle holder is latched relative to the
barrel to hold the needle holder in its advanced position against
the urging of the spring, and an open position in which the needle
holder is unlatched relative to the barrel to allow the spring to
expand in a proximal direction to move the needle holder to its
retracted position.
Inventors: |
Mahurkar, Sakharam D.;
(Chicago, IL) |
Correspondence
Address: |
JENKENS & GILCHRIST, P.C.
225 WEST WASHINGTON
SUITE 2600
CHICAGO
IL
60606
US
|
Family ID: |
26729113 |
Appl. No.: |
10/051140 |
Filed: |
January 22, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60333721 |
Nov 28, 2001 |
|
|
|
Current U.S.
Class: |
604/192 ;
128/919 |
Current CPC
Class: |
A61M 2005/3206 20130101;
A61M 5/31511 20130101; A61M 5/3232 20130101; A61M 25/0631 20130101;
A61M 25/0606 20130101 |
Class at
Publication: |
604/192 ;
128/919 |
International
Class: |
A61M 005/32 |
Claims
What is claimed is:
1. A safety syringe assembly, comprising: an elongated, generally
cylindrical barrel having a hollow interior forming a hollow nozzle
located at a distal end of said barrel and opening into the
interior of said barrel and an expanded proximal segment; a plunger
slidably mounted in said barrel and having a longitudinal open
channel; a needle; a needle holder mounting said needle at a distal
end thereof and slidably mounted in said longitudinal open channel
of said plunger for movement between an advanced position in which
said needle on the distal end of said needle holder projects from a
distal end of said nozzle, and a retracted position in which said
needle is retracted within said barrel; a compression spring
mounted inside of said barrel, and a spring retainer element
located in said expanded proximal segment of said barrel and having
a stabilizing surface extending along and about a portion of the
internal wall of said barrel, and a spring support portion
extending from said stabilizing surface interiorly of said barrel
and supporting a distal end portion of said spring against
expansion, said spring retainer also having a through opening for
freely receiving said needle holder therethrough; said spring
urging said needle holder toward its retracted position; and a
latch having an engaged position in which said needle holder is
latched relative to said barrel to hold said needle holder in its
advanced position against the urging of said spring, and a
disengaged position in which said needle holder is unlatched
relative to said barrel to allow said spring to expand in a
proximal direction to move said needle holder to its retracted
position.
2. The syringe assembly of claim 1 wherein said latch is
inseparably mounted to said barrel.
3. The syringe assembly of claim 1 wherein said spring is a helical
spring disposed around said needle and said needle holder.
4. The syringe assembly of claim 1 wherein said latch is mounted so
as to be activated by advance of said plunger.
5. The syringe assembly of claim 1 wherein said latch is mounted on
an external surface of the barrel.
6. The syringe assembly of claim 1 wherein said barrel includes a
track slot and wherein said needle holder includes a lateral arm
extending laterally from said plunger open channel into said track
slot, whereby said needle holder is guided by said track slot as it
moves toward its retracted position.
7. The syringe assembly of claim 6 wherein said latch is mounted
for movement into and out of registry with a distal end of said
track slot for capturing and releasing said lateral arm at the
distal end of said track slot.
8. A retractable needle safety syringe assembly, comprising: a
hollow generally cylindrical barrel, with a distal hollow nozzle
communicating with the barrel; a plunger slidably inserted in the
barrel, having a polymeric piston at a distal end, and a
longitudinal open channel; a needle holder with a needle mounted at
the distal end thereof and slidably mounted in said longitudinal
open channel of said plunger for movement between an advanced
position in which said needle on the distal end of said needle
holder projects from a distal end of said nozzle, and a retracted
position in which said needle is retracted within said barrel; a
compression spring wrapped around said needle holder; said plunger
having linear axial mobility independent of movements of the spring
and needle holder; a spring retainer located in said barrel
supporting said compression spring; a switch engaging the barrel
and the needle holder and having two radial projections entering
within the barrel cavity; said plunger advancing the polymeric
piston to make a surface contact of a distal conical end of the
piston with a conical interior end of the barrel for injecting
medicine through the needle by minimal force applied to said
plunger; said plunger being movable with an additional applied
force to advance distally within a cavity formed in the piston as
well as to compress the piston thereby additionally advancing
distally within the barrel, a pair of plates projecting from the
plunger engaging and radially displacing said projections of the
switch upon said additional advance, so as to displace the switch
radially outwardly causing the release and retraction of the needle
holder.
9. The assembly of claim 8 having a barrel with proximal wider
segment that accommodates a spring retainer.
10. The syringe assembly of claim 8 including a needle protector,
and wherein said nozzle of said barrel has a male luer taper on its
outer surface that mates with a female luer taper interior of the
said needle protector creating a taper lock to form an air and
water tight seal between the barrel nozzle and needle protector,
whereby air or fluids residing in the sealed barrel prevent advance
of the plunger to the distal end of the barrel, avoiding the
retraction before the use of the syringe.
11. The syringe assembly of claim 9, wherein the switch mechanism
is located outside a fluid chamber defined in said barrel, and
advancement of the plunger in a fluid-filled barrel generates a
hydraulic pressure gradient that is relieved by the exit of said
fluid from the needle such that any increase in the hydraulic
pressure in the barrel as a result of an imbalance of generation
and relief of the pressures tends to prevent rather than encourage
retraction of the needle.
12. The assembly of claim 11 wherein said hydraulic pressure
gradient prevents accidental retraction by preventing the contact
between the projecting parts on the plunger and on the latch.
13. The assembly of claim 8 wherein the spring and needle holder
are located proximal to said polymeric piston mounted to a distal
end of said plunger whose movements are responsible for generation
of pressure and vacuum in the barrel and which is not affected by
pressure gradients within the barrel.
14. The syringe assembly of claim 8 wherein said spring is a coil
spring and is sized to fit in said open channel of said
plunger.
15. A safety syringe assembly, comprising: an elongated, generally
cylindrical barrel having a hollow interior forming a hollow nozzle
located at a distal end of said barrel and opening into the
interior of said barrel; a plunger slidably mounted in said barrel
and having a longitudinal open channel; a needle holder slidably
mounted in said longitudinal open channel of said plunger for
movement between an advanced position in which a needle on the
distal end of said needle holder projects from a distal end of said
nozzle, and a retracted position in which said needle is retracted
within said barrel; a spring mounted inside said barrel and urging
said needle holder toward its retracted position; and a latch
having an engaged position in which said needle holder is latched
to said barrel to hold said needle holder in its advanced position
against the urging of said spring, and a disengaged position in
which said needle holder is unlatched from said barrel to allow
said spring to move said needle holder to its retracted position;
wherein said latch comprises a needle holder locking element
non-removably, circumferentially mounted on said barrel for rotary
movement between a locking position and non-locking position on the
barrel relative to said needle holder.
16. The syringe assembly of claim 15 wherein said barrel has
outwardly extending gripping flanges, and one or more detent
elements parallel to and axially spaced from said outwardly
extending gripping flanges and said needle holder locking element
is mounted between said detent elements and said barrel
flanges.
17. The syringe assembly of claim 16 wherein said needle holder
includes a lateral arm which extends radially through an axial
elongate slot through the barrel wall and distal to said flanges,
and wherein said latch is located adjacent said flanges to engage a
portion of said lateral arm.
18. The syringe assembly of claim 15 and further including a spring
retaining member for supporting a distal end portion of the spring
inside the barrel.
19. The syringe assembly of claim 17 and further including a
retaining member for supporting a distal end portion of the spring
inside the barrel, a proximal end of said spring abutting said
lateral arm of said needle holder.
20. The syringe assembly of claim 15 wherein said latch has at
least one inwardly projecting member extending through a wall of
said barrel, and wherein said plunger includes at least one an
outwardly projecting part for engaging said projecting member upon
advancement of said plunger past a position for fully dispensing
medication, for releasing said latch.
21. A retraction control unit for a retractable needle syringe
comprising: a cylindrical spring retainer with a distal axial
cantilever extension, inserted coaxially and locked within a barrel
of a syringe; a plunger with a compressibly engaged resilient cap,
one or more radial projections and a central channel, and capable
of reciprocal linear movements, and inserted within said spring
retainer clearing the cantilever; a needle holder slidably mounted
in said central open channel of said plunger for movement between
an advanced position in which a needle on the distal end of said
needle holder projects from a distal end of said nozzle, and a
retracted position in which said needle is retracted within said
barrel; the distal axial cantilever extension of the said spring
retainer retaining a compression spring wrapped around said needle
holder, such that said needle holder passes distally through an
opening in the said axial extension; a proximal surface of said
spring retainer having a stabilizer plate to support the needle
holder and a deflectable anchoring plate that releasably holds the
needle holder against an expansion force of the spring until it is
radially deflected by the projections of said plunger, in response
to a force that exceeds a fluid injection force.
22. A needle retraction mechanism for a retractable safety syringe
comprising: support means in the form of a hollow cylindrical
tubular segment engageable to the internal surface of a syringe
barrel by mechanical or chemical means and having an axially
extending cantilever means with an opening on its distal surface
for supporting biasing means in the form of a compression spring
engaged with a needle holder, and a needle holder anchoring plate
having needle holder retaining geometry preventing needle holder
means from retracting from the support means and located on a
surface of support means opposite of the cantilever means; needle
holder means with a needle at its distal end slidably engaged in
the opening of said cantilever means for linear movements between
an advanced position in which a needle on the distal end of said
needle holder projects from a distal end of the syringe barrel, and
a retracted position in which said needle is retracted within said
syringe barrel; plunger means with a compressably engaged elastic
cap, and a central channel that clears the cantilever means and the
needle holder means in the barrel for reciprocal linear movements
to receive and inject medication from the syringe; said plunger
means having radially projecting ramps flanking said central
channel and being advanceable to create a first pressure gradient
to inject medicine through the needle and a second pressure
gradient to compress a plunger-cap junction and the elastic cap so
as to cause the plunger ramps to engage and displace the anchoring
plate of the support means to disengage and retract the needle
holder; wherein said needle holder means is releasably engaged by
said anchoring plate at a distal end of a retraction chamber of the
barrel counteracting said compression spring and advancing the
needle holder distally to define an operative mode of the syringe;
and wherein said support means are inseparable from the barrel in
an operative mode but, when said anchoring plate is displaced,
release the needle holder and needle within the barrel.
23. A syringe assembly, comprising: an elongated, tubular barrel
having a hollow interior forming a hollow nozzle located at a
distal end of said barrel and opening into the interior of said
barrel; a plunger slidably mounted in said barrel and having a
longitudinal open channel; a needle holder slidably mounted in said
longitudinal open channel of said plunger; a latch for latching and
unlatching said needle holder relative to said barrel; and a spring
for retracting said needle holder in response to unlatching of said
needle holder by said latch; wherein said needle holder has a
lateral arm which extends radially, wherein said latch releasably
engages the lateral arm of said needle holder; and wherein said
latch inseparably engages said barrel.
24 The syringe assembly of claim 23 wherein said latch is rotatably
mounted on said barrel for rotary movement between a locking
position and non-locking position relative to said lateral arm.
25. The syringe assembly of claim 25 wherein said latch has an
inwardly projecting member extending through a wall of said barrel,
and wherein said plunger includes an outwardly projecting part for
engaging said inwardly projecting member upon advancement of said
plunger past a position for fully dispensing medication for
releasing said latch.
26. The syringe assembly of claim 23 wherein said barrel has a
cross section that is generally circular.
27. The syringe assembly of claim 23 wherein the barrel of the said
syringe is cylindrical and circular in cross-section.
28. The syringe assembly of claim 25 wherein said plunger includes
a portion for releasing engagement of said latch upon advancement
of said plunger past a position for fully dispensing medication for
releasing said latch.
29. The syringe assembly of claim 25 wherein a track slot is formed
in a proximal wall portion of said barrel for receiving said
lateral arm therethrough and guiding said lateral arm between a
fully advanced position and a fully retracted portion, said latch
being positioned for releasably engaging said lateral arm at a
distal end of said track slot.
30. The syringe assembly of claim 25 wherein said longitudinal open
channel of said plunger includes a detent for engaging and
retaining said needle holder when in a fully retracted
position.
31. The syringe assembly of claim 30 wherein said needle holder has
a recess at a proximal end thereof for engaging said plunger
detent.
32. A syringe assembly, comprising: an elongated, generally
cylindrical barrel having a hollow interior forming a hollow nozzle
located at a distal end of said barrel and opening into the
interior of said barrel, a plunger slidably mounted in said barrel
and having a longitudinal open channel; a needle holder slidably
mounted in said longitudinal open channel of said plunger; a latch
for latching and unlatching said needle holder relative to said
barrel; and a spring for retracting said needle holder in response
to unlatching of said needle holder by said latch; wherein said
needle holder has a lateral arm which extends radially, and wherein
said latch releasably engages the lateral arm of said needle
holder; wherein said latch is located and configured so as to be
activated by said plunger.
33. The syringe assembly of claim 32 wherein said latch has a
lateral arm engaging portion for releasably engaging said needle
holder lateral arm.
34. The syringe assembly of claim 32 wherein said plunger includes
a portion for releasing engagement of said latch upon advancement
of said plunger past a position for fully dispensing
medication.
35. The syringe assembly of claim 34 wherein longitudinal walls of
said plunger which define said longitudinal open channel include
projecting release elements for engaging and radially displacing
said latch so as to disengage said lateral arm engaging portion
from said needle holder lateral arm upon advancement of said
plunger past a position for fully dispensing medication.
36. A retractable needle pre-filled safety syringe assembly,
comprising: an elongated, generally cylindrical barrel having a
hollow interior forming a hollow nozzle at the distal end of said
barrel and opening into the interior of said barrel; an elastic O
ring seated adjacent the nozzle; a plunger with an elastic piston
that seals around an interior of the barrel and is slidably mounted
in said barrel, said plunger having a longitudinal open channel; a
needle holder slidably mounted in said longitudinal open channel of
said plunger for movement between an advanced position in which a
needle on the distal end of said needle holder projects from said
nozzle and seals against said O ring and a retracted position in
which said needle is retracted within said barrel; a compression
spring mounted around said needle holder and retracting the needle
holder proximally when expanded and the needle holder projecting
distally when the spring is compressed; wherein a medicine chamber
defined in said barrel is proximally sealed with the rubber piston
abutting against the needle holder while a needle lumen closed by
mechanical means seals the chamber distally.
37. The assembly of claim 36 wherein said nozzle has a male taper
on its outer surface; and further including a needle protector with
a mating female taper on an interior surface to form an air and
water tight seal between the barrel and needle protector.
38. The assembly of claim 36 wherein a medicine chamber defined
within said barrel is totally sealed and isolated from a retraction
mechanism comprising the needle holder and the compression
spring.
39. The assembly of claim 36 wherein the needle protector is filled
with a non-coring elastomer.
40. The assembly of claim 36 wherein the nozzle and needle
protector are provided with mating luer tapers to securely lock the
needle protector to the nozzle.
41. The assembly of claim 36 and further including a latch having
an engaged position in which said needle holder is latched relative
to said barrel to hold said needle holder in its advanced position
against the urging of said spring, and a disengaged position in
which said needle holder is unlatched relative to said barrel to
allow said spring to expand in a proximal direction to move said
needle holder to its retracted position.
42. The assembly of claim 36 wherein said latch is inseparably
mounted to said barrel.
43. The assembly of claim 36 wherein a portion of the plunger of
the prefilled syringe that projects proximally from the barrel is
split and folded along side of the barrel to reduce the volume of
the prefilled syringe, and can be unfolded for injection of the
medicine from the prefilled syringe.
44. The assembly of claim 43 wherein the split and folded plunger
is incapable of spontaneous movements so as to preserve the
integrity of the volume of medicine in the barrel.
45. A retractable needle safety syringe assembly, comprising: a
hollow generally cylindrical barrel, with a wider proximal segment
and a distal hollow nozzle communicating with the barrel; a needle
holder holding a hollow hypodermic needle mounted at a distal end
and a side aperture in said needle holder communicating with the
needle; a compression spring wrapped around the needle holder
biasing said needle in a direction for retracting the needle; a
spring retainer located in the wider segment of the said barrel and
supporting said compression spring; a plunger slidably inserted in
the barrel, and having an elastomeric piston at a distal end and a
central cavity enclosing the needle holder and needle, the plunger
having linear axial mobility in barrel independently of said spring
and needle holder; and a ring-like switch encircling the barrel and
rotatably locked onto the barrel surface, and engaging with said
needle holder to releasably compress the spring, said switch being
inseparable from said syringe at least until release of said needle
holder by said switch for retraction of the needle within the
syringe assembly.
46. The assembly of claim 45 wherein the switch is coaxial with the
barrel.
47. A retractable needle safety syringe assembly, comprising: a
hollow generally cylindrical barrel, with a wider proximal segment
and a distal hollow nozzle communicating with said barrel; a needle
holder holding a hollow hypodermic needle mounted at a distal end
of the needle holder and a side aperture in said needle holder
communicating with the needle; a compression spring wrapped around
the needle holder for biasing said needle in a direction for
retracting the needle; a spring retainer located in the wider
segment of said barrel and supporting said compression spring; a
plunger slidably inserted in the barrel, and having an elastomeric
piston at a distal end and a central open channel enclosing the
needle holder and needle, the plunger having linear axial mobility
in barrel, that is independent of said spring and needle holder; a
latch having an engaged position in which said needle holder is
latched relative to said barrel to hold said needle holder in its
advanced position against the urging of said spring, and a
disengaged position in which said needle holder is unlatched
relative to said barrel to allow said spring to expand in a
proximal direction to move said needle holder to its retracted
position; said latch comprising a semicircular element engaged on
the barrel, and having two radial projections entering with the
barrel cavity and engageable by said plunger for releasing said
switch upon over-advancement of said plunger; wherein said barrel
includes a track slot and wherein said needle holder includes a
lateral arm extending laterally from said plunger open channel into
said track slot, whereby said needle holder is guided by said track
slot as it moves toward its retracted position; and wherein a
distal margin of the switch engages the needle holder arm to
compress the spring and thereby retain the needle extended out
through the nozzle, and wherein the switch is inseparable from said
syringe assembly until the switch is released to retract the needle
within the syringe assembly.
48. The assembly of claim 47 wherein the switch is coaxial to the
barrel.
49. The assembly of claim 47 wherein said track slot is located in
a proximal part of barrel to engage the needle holder arm for
proximal linear retraction.
50. The assembly of claim 47 wherein the track slot in the barrel
wall is covered and closed.
51. The assembly of claim 47 wherein the barrel has outwardly
extending gripping flanges, and the switch has two vertical
diametric extensions that engage and project through respective
slots on the flanges of the barrel and permit radial movement of
the switch to release the needle holder arm.
52. The assembly of claim 47 wherein the needle holder arm is
released by an outward radial displacement of the switch in
response to linearly advancing the plunger within the barrel.
53. The assembly of claim 47 wherein said plunger has a pair of
elongate, parallel radially extending walls which define said
central open channel for receiving and positioning said needle
holder and said compression spring, and wherein each of said walls
includes a projection positioned for engagement with said switch
projection upon over-advancement of said plunger.
54. A retractable needle safety syringe assembly, comprising: a
hollow generally cylindrical barrel having an increased diameter
proximal segment and a distal hollow nozzle communicating with the
said barrel; a hollow needle; a plunger slidably arrested in the
barrel and having a longitudinal open channel; a needle holder
mounting said needle at a distal end thereof and slidably mounted
in said longitudinal open channel of said plunger for movement
between an advanced position in which said needle on the distal end
of said needle holder projects from a distal end of said nozzle,
and a retracted position in which said needle is retracted within
said barrel; a compression spring; a spring retainer located in
said increased diameter proximal segment of said barrel and
supporting said compression spring around said needle holder, said
needle holder having a lateral port communicating with the hollow
needle; wherein said barrel includes a track slot and wherein said
needle holder includes a lateral arm extending laterally from said
plunger open channel into said track slot, whereby said needle
holder is guided by said track slot as it moves toward its
retracted position; an elastomeric piston at a distal end of the
plunger; a ring switch encircling the barrel and rotatably locked
onto the barrel, distal to a pair of flanges and proximal to a pair
of detents on the barrel surface, engaging with the arm of the said
needle holder to compress the spring to bias the needle out through
the nozzle, and inseparable from the syringe until the needle is
retracted within the syringe assembly by release of the needle
holder; the nozzle of the syringe having a male taper on its outer
surface; and a needle protector with a complementary female taper
on a mating surface to form an air and water tight seal between the
barrel nozzle and needle protector, whereby pneumatic and hydraulic
forces caused by sealed fluids in the barrel prevent advance of
plunger and inadvertent retraction of the said needle.
55. The assembly of claim 54 wherein the barrel has a wider wall
proximal segment defining said track slot.
56. The assembly of claim 54 wherein said slot is in a proximal
part of barrel to engage the needle holder arm for proximal linear
retraction.
57. The assembly of claim 54 wherein the slot in the barrel wall is
covered and closed.
58. The assembly of claim 54 wherein the plunger has linear axial
mobility independent of movements of the spring and needle
holder.
59. A retractable needle safety syringe assembly, comprising: an
elongated, generally cylindrical barrel having a hollow interior
forming a hollow nozzle located at a distal end of said barrel and
opening into the interior of said barrel; a plunger slidably
mounted in said barrel and having a longitudinal open channel; a
needle; a needle holder mounting said needle at a distal end
thereof, and releasably coupled to the said barrel for movement
between an advanced position in which a needle on the distal end of
said needle holder projects from a distal end of said nozzle, and a
retracted position in which said needle is retracted with said
barrel; a compression spring mounted around the needle holder
biasing the needle holder in a direction for retracting the needle
proximally when expanded; said nozzle having a male taper on its
outer surface with a needle protector with a mating female taper to
form an air and water tight seal between the barrel and needle
protector; whereby fluids residing in the barrel preventing advance
of the plunger to the distal end of the barrel and avoiding the
retraction before the use of the syringe.
60. A retractable needle safety syringe assembly, comprising: an
elongated, generally cylindrical barrel having a hollow interior
forming a hollow nozzle located at a distal end of said barrel and
opening into the interior of said barrel; a plunger slidably
mounted in said barrel and having a longitudinal open channel; a
needle holder receiving said needle at its distal end and slidably
mounted in said longitudinal open channel of said plunger for
movement between an advanced position in which said needle projects
form a distal end of said nozzle, and a retracted position in which
said needle is retracted within said barrel; wherein said barrel
includes a track slot and wherein said needle holder includes a
lateral arm extending laterally from said plunger open channel into
said track slot, whereby said needle holder is guided by said track
slot as it moves toward its retracted position; a rotatable ring
switch that encircles said barrel and engages with the needle
holder arm projecting from the barrel wall; a compression spring
mounted around the needle holder and assembled to the barrel and
biasing the needle holder for retracting the needle proximally when
expanded; the nozzle having a male taper on its outer surface, and
a needle protector with a mating female taper to form an air and
water tight seal between the barrel and needle protector; whereby
the retractable needle syringe assembly is sealed at the nozzle by
the needle protector, such that in an operative state the syringe
contains a quantum of air to prevent accidental advance of the
plunger and to avoid premature retraction of the needle and
disablement of the syringe.
61. A retractable needle safety syringe assembly, comprising: a
hollow generally cylindrical barrel, with a distal hollow nozzle
communicating with the barrel; a plunger slidably inserted in the
barrel, having a polymeric piston at the distal end, and a
longitudinal open channel; a needle; a needle holder mounting said
needle at a distal end thereof and slidably mounted in said
longitudinal open channel of said plunger for movement between an
advanced position in which said needle on the distal end of said
needle holder projects from a distal end of said nozzle, and a
retracted position in which said needle is retracted within said
barrel; a compression spring wrapped around the said needle holder;
a spring retainer located in the said barrel supporting said
compression spring; said plunger having linear axial mobility
independent of movements of the spring and needle holder. a switch
engaged on the barrel and having two radial projections entering
within the barrel cavity; said plunger advancing the polymeric
piston to make a surface contact of a piston distal conical end
with a conical interior end of barrel for injecting medicine
through the needle by minimal force applied to said plunger; said
plunger being movable with an additional applied force to advance
distally within a cavity formed in the rubber piston cavity and so
as compress the elastic rubber piston thereby additionally
advancing distally within the barrel; and a pair of plates
projecting from the plunger engaging and radially displacing said
projections of the switch upon said additional advance, so as to
displace the switch radially outwardly causing the release and
retraction of the needle holder.
62. The assembly of claim 61 having a barrel with proximal wider
segment that accommodates a spring retainer.
63. A retractable needle safety syringe assembly, comprising: an
elongated, generally cylindrical barrel having a hollow interior
forming a hollow nozzle located at a distal end of said barrel and
opening into the interior of said barrel; a plunger slidably
mounted in said barrel and having a longitudinal open channel; a
needle; a needle holder slidably mounted in said longitudinal open
channel of said plunger for movement between an advanced position
in which said needle, held on the distal end of said needle holder,
projects from a distal end of said nozzle, and a retracted position
in which said needle is retracted within said barrel; a compression
spring mounted around the needle holder and assembled to the
barrel, and biasing the needle holder in a direction for retracting
the needle proximally when expanded; said needle having an open
proximal end mounted in and sealed by adhesives to a distal dead
end of the needle holder such that the open proximal end of the
needle is not exposed to air in the barrel; an entry and exit hole
for medication located in a lateral wall of the needle holder and
in communication with said needle, that is a boundary zone of zero
velocity and is only affected by a pressure gradient in the barrel
and not by retraction of the needle; said needle holder having a
larger cross-section at its proximal portion which adds significant
mass to dampen the retraction velocity of the needle holder, and
wherein the expansion spring is always in contact with the needle
holder to provide minimum recoil to needle and its contents.
64. A retractable needle safety syringe comprising: an elongated,
generally cylindrical body forming an aperture at the distal end of
said cylindrical body and opening into the interior of said
cylindrical body; a needle holder carrying a hollow hypodermic
needle projecting from said holder along the axis of said
cylindrical body, said needle holder being mounted for longitudinal
movement between retracted and advanced positions within said
elongated cylindrical body; a releasable latch for releasably
locking said cylindrical body and said needle holder to each other;
biasing means within said cylindrical body for biasing said needle
holder toward said retracted position; a plunger carrying said
needle holder and mounted for longitudinal movement between
retracted and advanced positions within said elongated cylindrical
body, said plunger being movable to a first advanced position in
response to an applied manual force of a first magnitude, and to a
second advanced position in response to an applied manual force of
a second, greater magnitude; and means for releasing said latch in
response to movement of said plunger to said second advanced
position, so that said needle holder is retracted by said biasing
means upon movement of said plunger to said second advanced
position.
65. The syringe of claim 64 which includes a resilient,
compressible piston on the distal end portion of said plunger.
66. The syringe of claim 65 wherein an interface between said
piston and said end portion of said plunger is formed to permit
said plunger to advance further by compressing said piston after
said piston has bottomed out on a distal end of the interior of
said cylindrical body.
67. The syringe of claim 64 wherein said piston includes a
substantially flat surface on a proximal end thereof, and said
plunger includes a substantially flat annular flange engaging said
substantially flat surface on said piston.
68. A retractable needle safety syringe comprising: an elongated,
generally cylindrical body forming an aperture at the distal end of
said cylindrical body and opening into the interior of said
cylindrical body; a needle holder carrying a hollow hypodermic
needle projecting from said holder along the axis of said
cylindrical body, said needle holder being mounted for longitudinal
movement between retracted and advanced positions within said
elongated cylindrical body; a plunger carrying said needle holder
and mounted for longitudinal movement between retracted and
advanced positions within said elongated cylindrical body; biasing
means within said cylindrical body for biasing said needle holder
toward said retracted position; and a releasable latch for
releasably locking said cylindrical body and said needle holder to
each other, said latch having a latch body that extends at least
partially around the circumference of said cylindrical body and is
attached to said cylindrical body, said latch being movable between
an engaged position in which said needle holder is latched in its
advanced position against he urging of said biasing means, and a
disengaged position in which said needle holder is unlatched to
allow said biasing means to move said needle holder to its
retracted position.
69. A retractable needle safety syringe pre-filled with a liquid to
be administered to a patient, said syringe comprising: an
elongated, generally cylindrical barrel of biocompatible
thermoplastic forming a medicine chamber traversed by an axial
biocompatible needle holder with a hypodermic needle attached to
its distal end, and retained in the chamber by a reversible
interlock of said barrel with said needle holder; said needle
holder being mounted for longitudinal movement between retracted
and advanced positions within said elongated cylindrical barrel; a
releasable latch for releasably locking said cylindrical barrel and
said needle holder to each other; a compression spring within said
cylindrical barrel for biasing said needle holder toward said
retracted position; a plunger carrying said needle holder and
mounted for longitudinal movement between retracted and advanced
positions within said elongated cylindrical barrel, the distal end
of said plunger including a resilient piston which seals against an
internal wall of the barrel; wherein said needle holder is sealed
by an "O" ring at a distal nozzle formed on said barrel, while the
needle is also mechanically closed by a luer locked needle
protector at the nozzle, wherein proximally, the barrel including
the needle holder is sealed by the resilient piston; the plunger
having a channel that permits an advance of the plunger for
injection of medicine as well as retraction of the needle holder
and the needle within the barrel when the medicine has been
injected, and the latch has been released; wherein the integrity of
needle holder location and the retraction and locking of the needle
holder in the barrel is achieved by the compression spring
installed on a spring retainer and engaged with the needle holder;
and wherein sealing of the medicine chamber prior to injection of
the medicine is additionally supported by the spring retainer.
70. A retractable needle safety saline filled syringe assembly for
intravenous catheter placement, comprising: an over-the-needle
catheter comprising a flexible polymeric tubular catheter having a
mounting connector with a female luer taper; a hollow generally
cylindrical barrel and a distal hollow nozzle communicating with
said barrel, and having male luer taper on its outer surface that
engages with said female luer taper of the over-the-needle catheter
to thereby mount the catheter on the nozzle; a hypodermic needle
mounted to a needle holder; said catheter being coaxially
installable over the hypodermic needle emerging out through the
nozzle and extending beyond the tip of said catheter; a compression
spring wrapped around the needle holder and urging said needle
holder toward its retracted position; a spring retainer element
having a spring support portion extending interiorly in the center
of the barrel and supporting a distal end portion of the
compression spring encircling the hypodermic needle, while
permitting the passage of the said hypodermic needle through the
compressed spring and an opening in said support portion, through
the nozzle and within said over-the-needle catheter; a plunger
slidably inserted in the barrel, having a resilient piston at its
distal end, and a central cavity receiving said spring support, the
spring and the needle holder; said needle holder having a side arm
at its proximal end which compresses the spring inside the spring
retainer so as to cause said needle to project distally through the
nozzle of the syringe and which is releasably attached to the
barrel via a switch; whereby in normal operative mode the saline
filled syringe is used puncture the skin and a vein by the needle
point to gain entry of the needle and the catheter into a vein, the
hypodermic needle is retracted and the catheter remains on the
nozzle for further advance and maintenance of fluid communication
with said syringe for monitoring the location of the catheter and
infusing fluids into the vein; and the hypodermic needle is
retracted, while the flexible catheter is retained on the nozzle
for non-traumatic manipulation and placement, and for monitoring
the location of the catheter and fluid continuity through said
catheter before connecting to intravenous fluid lines.
71. The assembly of claim 70 wherein the barrel has a wider
proximal segment.
72. The assembly of claim 70 wherein a puncturing bevel point of
said needle is exposed beyond the catheter while its female luer
end is anchored onto the nozzle of the said barrel.
73. A retractable needle, single use syringe comprising: a hollow
generally cylindrical barrel, with a wider proximal segment and a
distal hollow nozzle communicating with an interior of said barrel;
a needle; a needle holder mounting said needle at a distal end
thereof and slidably mounted in said longitudinal open channel of
said plunger for movement between an advanced position in which
said needle projects from a distal end of said nozzle, and a
retracted position in which said needle is retracted within said
barrel; a compression spring mounted inside said barrel and urging
said needle holder toward its retracted position; and a plunger
slidably inserted in the barrel said plunger, having an elastomeric
piston at a distal end, said plunger having linear axial mobility
independent of movements of the needle holder and spring; a switch
mounted to said barrel and having an engaged position in which said
needle holder is latched relative to said barrel to hold said
needle holder in its advanced position against the urging of said
spring, and a disengaged position in which said needle holder is
unlatched relative to said barrel to allow said spring to expand in
a proximal direction to move said needle holder to its retracted
position to disable the syringe and prevent reuse of the syringe;
axially spaced flanges and detents on said barrel; wherein the
switch encircles the barrel and is locked onto the barrel, distal
to the flanges and proximal to the detents on the barrel surface;
said switch engaging with said needle holder to compress the spring
and being inseparable from said barrel until the needle holder is
released by the switch and the needle is retracted within the
syringe.
74. The single use syringe of claim 73 wherein the expanded length
of the spring exceeds the length of the needle, whereby the syringe
is non-reusable once the needle holder is released and the needle
is retracted within the syringe.
75. The single use syringe of claim 73 wherein the needle holder
has a recess engageable with a detent located on a proximal portion
of the plunger for locking the needle holder in its retracted
position, whereby the syringe is non-reusable.
76. The single use syringe of claim 73 wherein the needle holder
once retracted is non-removably locked with a margin of the
proximal end of the barrel, whereby the syringe is
non-reusable.
77. The single use syringe of claim 73 and further including a
spring retainer for supporting a distal end portion of the spring
inside the barrel wherein the spring retainer is locked within the
wider proximal segment of the barrel between a shoulder formed
thereby at a distal, narrower portion of the barrel and an internal
elevated ring within the wider portion of the barrel, whereby the
syringe is non reusable.
78. The single use syringe of claim 77 wherein the spring is locked
between the spring retainer and the needle holder and cannot be
taken out or recompressed, once expanded, whereby the syringe is
non-reusable.
79. The single use syringe of claim 73 and further including a
spring retainer element having a spring support portion extending
interiorly of said barrel and supporting a distal end portion of
said spring against expansion, said spring retainer also having a
through opening for freely receiving said needle holder
therethrough; and wherein upon retraction the spring retainer also
engages a detent on the plunger and locks the plunger to the spring
retainer, whereby the syringe is non reusable.
80. The single use syringe of claim 73 wherein the barrel
circumference is rendered non deformable by projecting ribs on the
plunger, whereby the needle holder cannot be removed and the
syringe is non reusable.
81. The single use syringe of claim 73 wherein said barrel has
outwardly extending gripping flanges, and one or more detent
elements parallel to and axially spaced from said outwardly
extending gripping flanges, and said switch is mounted between said
detent elements and said barrel flanges.
82. The single use syringe of claim 73 wherein, upon retraction of
the needle, every component of the syringe is directly or
indirectly locked with every other component of the syringe, such
that the entire assembly is interlocked whereby the syringe is
non-reusable.
83. The single use syringe of claim 73 wherein said barrel has
outwardly extending gripping flanges, and one or more detent
elements parallel to and axially spaced from said outwardly
extending gripping flanges, and said needle holder locking element
is mounted between said detent elements and said barrel flanges;
wherein said latch has an inwardly projecting member extending
through a wall of said barrel, and wherein said plunger includes an
outwardly projecting part for engaging said inwardly projecting
member upon advancement of said plunger past a position for fully
dispensing medication for releasing said latch.
84. A retractable needle safety syringe assembly, comprising: an
elongated, generally cylindrical barrel having a hollow interior
forming a hollow nozzle located at a distal end of said barrel and
opening into the interior of said barrel; a plunger slidably
mounted in said barrel and having a longitudinal open channel; a
needle holder slidably mounted in said longitudinal open channel of
said plunger for movement between an advanced position in which a
needle on the distal end of said needle holder projects from a
distal end of said nozzle and is sealed with an "O" ring, and a
retracted position in which said needle is retracted within said
barrel; a compression spring mounted around the needle holder and
retracting needle proximally when expanded, and a latch which at
least partly encircles the barrel and releasably engages with the
needle holder to hold the spring in a compressed condition; wherein
said latch has an inwardly projecting member extending through a
wall of said barrel, and wherein said plunger includes an outwardly
projecting part for engaging said projecting member and disengaging
said latch from said needle holder, upon advancement of said
plunger past a position for fully dispensing medication for
releasing said latch; wherein advancement of the plunger in a
fluid-filled barrel generates a hydraulic pressure gradient that is
relieved by the exit of said fluid from the needle such that any
increase in the hydraulic pressure in barrel as a result of an
imbalance of generation and relief of the pressures tends to
prevent rather than encourage retraction of the needle.
85. The assembly of claim 84 wherein said hydraulic pressure
gradient prevents accidental retraction by preventing the contact
between the projecting parts on the plunger and on the latch.
86. The assembly of claim 84 wherein the spring and needle holder
are located proximal to a polymeric piston mounted to a distal end
of said plunger whose movements are responsible for generation of
pressure and vacuum in the barrel and which is not affected by
pressure gradients within the barrel.
87. A syringe comprising: an elongated, generally cylindrical body
forming an aperture at the distal end of said cylindrical body and
opening into the interior of said cylindrical body; a needle holder
carrying a hollow hypodermic needle projecting from said holder
along the axis of said cylindrical body, said needle holder being
mounted for longitudinal movement between retracted and advanced
positions within said elongated cylindrical body; a releasable
latch for releasably locking said cylindrical body and said needle
holder to each other; biasing means within said cylindrical body
for biasing said needle holder toward said retracted position; a
plunger carrying said needle holder and mounted for longitudinal
movement between retracted and advanced positions within said
elongated cylindrical body, said 30 plunger being movable to a
first advanced position in response to an applied manual force of a
first magnitude, and to a second advanced position in response to
an applied manual force of a second, greater magnitude; and means
for releasing said latch in response to movement of said plunger to
said second advanced position, so that said needle holder is
retracted by said biasing means upon movement of said plunger to
said second advanced position, wherein said latch is located inside
of said barrel.
88. A safety syringe assembly, comprising: an elongated, generally
cylindrical barrel having a hollow interior forming a hollow nozzle
located at a distal end of said barrel and opening into the
interior of said barrel; a plunger slidably mounted in said barrel
and having a longitudinal open channel, said plunger being movable
to a first advanced position in response to an applied manual force
of a first magnitude, and to a second advanced position in response
to an applied manual force of a second, greater magnitude; a
needle; a needle holder mounting said needle at a distal end
thereof and slidably mounted in said longitudinal open channel of
said plunger for movement between an advanced position in which
said needle on the distal end of said needle holder projects from a
distal end of said nozzle, and a retracted position in which said
needle is retracted within said barrel; a compression spring
mounted inside of said barrel, and a spring retainer having a
spring support portion extending interiorly of said barrel and
supporting a distal end portion of said spring against expansion,
said spring retainer also having a through opening for freely
receiving said needle holder therethrough; said spring urging said
needle holder toward its retracted position; and a latch having an
engaged position in which said needle holder is latched relative to
said barrel to hold said needle holder in its advanced position
against the urging of said spring, and a disengaged position in
which said needle holder is unlatched relative to said barrel to
allow said spring to expand in a proximal direction to move said
needle holder to its retracted position, wherein said latch is an
integral part of said spring retainer.
89. The syringe assembly of claim 88 wherein said latch is located
in said hollow interior of said barrel.
90. The syringe assembly of claim 88 wherein said latch is mounted
so as to be activated by said plunger.
91. The syringe assembly of claim 88 wherein the plunger has a
projection that irreversibly engages with the spring retainer when
the plunger is in the second advanced position, whereby the syringe
is non-reusable.
92. A safety syringe assembly comprising: an elongated, generally
cylindrical barrel having a hollow interior forming a hollow nozzle
located at a distal end of said barrel and opening into the
interior of said barrel; a plunger slidably mounted in said barrel
and having a longitudinal open channel; a needle holder slidably
mounted in said longitudinal open channel of said plunger for
movement between an advanced position in which a needle on the
distal end of said needle holder projects from a distal end of said
nozzle, and a retracted position in which said needle is retracted
within said barrel; a spring mounted inside and barrel and urging
said needle holder toward its retracted position; and a latch
having an engaged position in which said needle holder is latched
to said barrel to hold said needle holder in its advanced position
against the urging of said spring, and a disengaged position in
which said needle holder is unlatched from said barrel to allow
said spring to move said needle holder to its retracted position;
wherein said latch is inseparably mounted to said barrel, in said
hollow interior of said barrel.
93. The syringe assembly of claim 91 wherein said latch is mounted
so as to be activated by said plunger.
94. The syringe assembly of claim 88 including a spring retainer
element mounted interiorly of said barrel and supporting a distal
end portion of said spring against expansion, and wherein said
latch is an integral part of said spring retainer.
95. The syringe assembly of claim 94 wherein the plunger has a
projection that irreversibly engages with the spring retainer when
the plunger is in the second advanced position, whereby the syringe
is non-reusable.
96. A safety syringe assembly, comprising: an elongated, generally
cylindrical barrel having a hollow interior forming a hollow nozzle
located at a distal end of said barrel and opening into the
interior of said barrel; a plunger slidably mounted in said barrel
and having a longitudinal open channel; a needle holder slidably
mounted in said longitudinal open channel of said plunger for
movement between an advanced position in which a needle on the
distal end of said needle holder projects from a distal end of said
nozzle, and a retracted position in which said needle is retracted
within said barrel; a spring mounted inside said barrel and urging
said needle holder toward its retracted position; and a latch
having an engaged position in which said needle holder is latched
to said barrel to hold said needle holder in its advanced position
against the urging of said spring, and a disengaged position in
which said needle holder is unlatched from said barrel to allow
said spring to move said needle holder to its retracted position;
wherein said latch comprises a needle holder locking element
non-removably mounted to said barrel, in said hollow interior, and
movable between a locking position and non-locking position
relative to said needle holder.
97. The syringe assembly of claim 96 wherein said latch is mounted
so as to be activated by said plunger.
98. The syringe assembly of claim 96 including a spring retainer
element mounted interiorly of said barrel and supporting a distal
end portion of said spring against expansion, and wherein said
needle holder locking element is an integral part of said spring
retainer.
99. A syringe assembly, comprising: an elongated, generally
cylindrical barrel having a hollow interior forming a hollow nozzle
located at a distal end of said barrel and opening into the
interior of said barrel; a plunger slidably mounted in said barrel
and having a longitudinal open channel; a needle slidably mounted
in said longitudinal open channel of said plunger and having a
radially projecting arm; a latch for latching and unlatching said
needle holder relative to said barrel; said latch engaging said
radially projecting arm on said needle holder by which the needle
holder engaged with the barrel, thereby releasably latching said
needle holder relative to said barrel; and a compression spring
located in said barrel in surrounding relation to said needle
holder and having a distal end held against expansion so as to
expand in a proximal direction for retracting said needle holder in
response to unlatching said needle holder by said latch; wherein
said latch and said needle holder are at all times located in said
hollow interior of said barrel.
100. The syringe assembly of claim 99 wherein said latch is mounted
so as to be activated by said plunger.
101. The syringe assembly of claim 99 including a spring retainer
element mounted interiorly of said barrel and supporting a distal
end portion of said spring against expansion, and wherein said
latch is an integral part of said spring retainer.
102. A syringe assembly, comprising: an elongated, generally
cylindrical barrel having a hollow interior forming a hollow nozzle
located at a distal end of said barrel and opening into the
interior of said barrel; a plunger slidably mounted in said barrel
and having a longitudinal open channel; a needle holder slidably
mounted in said longitudinal open channel of said plunger; a latch
for latching and unlatching said needle holder relative to said
barrel; and a spring for retracting said needle holder in response
to unlatching said needle holder by said latch; wherein said needle
holder has a lateral arm which extends radially, and wherein said
latch releasably engages the lateral arm of said needle holder;
wherein said latch and said lateral arm of said needle holder are
at all times located in said hollow interior of said barrel.
103. The syringe assembly of claim 102 including a spring retainer
element mounted interiorly of said barrel and supporting a distal
end portion of said spring against expansion, and wherein said
needle holder locking element is an integral part of said spring
retainer.
104. The syringe assembly of claim 102 wherein said latch is
mounted so as to be activated by said plunger.
105. A syringe assembly, comprising: an elongated, generally
cylindrical barrel having a hollow interior forming a hollow nozzle
located at a distal end of said barrel and opening into the
interior of said barrel; a plunger slidably mounted in said barrel
and having a longitudinal open channel; a needle holder slidably
mounted in said longitudinal open channel of said plunger; a latch
for latching and unlatching said needle holder relative to said
barrel; and a spring for retracting said needle holder in response
to unlatching said needle holder by said latch; wherein said latch
releasably engages said needle holder, wherein said latch is
mounted so as to be activated by said plunger, and wherein said
latch and said needle holder are at all times located in said
hollow interior of said barrel.
106. The syringe assembly of claim 105 wherein said plunger being
movable to a first advanced position in response to an applied
manual force of a first magnitude, and to a second advanced
position in response to an applied manual force of a second,
greater magnitude, and means for releasing said latch in response
to movement of said plunger to said second advanced position, so
that said needle holder is retracted by said spring upon movement
of said plunger to said second advanced position.
107. The syringe assembly of claim 105 including a spring retainer
element mounted interiorly of said barrel and supporting a distal
end portion of said spring against expansion, and wherein said
latch is an integral part of said spring retainer element.
108. A syringe comprising: an elongated, generally cylindrical body
forming an aperture at the distal end of said cylindrical body and
opening into the interior of said cylindrical body; a needle holder
carrying a hollow hypodermic needle projecting from said holder
along the axis of said cylindrical body, said needle holder being
mounted for longitudinal movement between retracted and advanced
positions within said elongated cylindrical body; a releasable
latch for releasably locking said cylindrical body and said needle
holder to each other; biasing means within said cylindrical body
for biasing said needle holder toward said retracted position; a
plunger carrying said needle holder and mounted for longitudinal
movement between retracted and advanced positions within said
elongated cylindrical body, said plunger being movable to a first
advanced position in response to an applied manual force of a first
magnitude, and to a second advanced position in response to an
applied manual force of a second, greater magnitude; and means for
releasing said latch in response to movement of said plunger to
said second advanced position, so that said needle holder is
retracted by said biasing means upon movement of said plunger to
said second advanced position, and means for locking said plunger
in said second advanced position.
109. The syringe of claim 108 and further including a spring
retainer element mounted interiorly of said barrel and supporting a
distal end portion of said spring against expansion, and wherein
said locking means includes cooperating elements located on said
spring retainer element and on said plunger.
110. A syringe comprising: an elongated, generally cylindrical body
forming an aperture at the distal end of said cylindrical body and
opening into the interior of said cylindrical body; a needle holder
carrying a hollow hypodermic needle projecting from said holder
along the axis of said cylindrical body, said needle holder being
mounted for longitudinal movement between retracted and advanced
positions within said elongated cylindrical body; a releasable
latch for releasably locking said cylindrical body and said needle
holder to each other; biasing means within said cylindrical body
for biasing said needle holder toward said retracted position; a
plunger carrying said needle holder and mounted for longitudinal
movement between retracted and advanced positions within said
elongated cylindrical body, said plunger being movable to a first
advanced position in response to an applied manual force of a first
magnitude, and to a second advanced position in response to an
applied manual force of a second, greater magnitude; and means for
releasing said latch in response to movement of said plunger to
said second advanced position, so that said needle holder is
released by said biasing means upon movement of said plunger to
said second advanced position, the nozzle of the syringe having a
male taper on its outer surface and a needle protector with a
complementary female taper on a mating surface to form an air and
water tight seal between the barrel nozzle and needle protector,
whereby pneumatic and hydraulic forces caused by sealed fluids in
the barrel prevent advance of plunger and inadvertent retraction of
the said needle.
111. A method of administering a medication, using a retractable
needle, single use syringe, said method comprising: applying a
manual force of a first magnitude in order to move a plunger of the
syringe to a first advanced position for dispensing medication;
applying a manual force of a second greater magnitude in order to
move said plunger to a second advanced position for releasing a
latch, so that a needle holder is released and retracted thereby
permanently retracting a needle within a body of the syringe.
112. A method of administering a medication using a retractable
needle, single use syringe, said method comprising: manually moving
a plunger to a first advanced position in response to an applied
manual force of a first magnitude for dispensing said medication;
and manually moving said plunger to a second advanced position in
response to an applied manual force of a second greater magnitude
for releasing a latch so that a needle holder is released and a
needle is retracted within a body of said syringe.
113. A method of intravenous catheter placement using a retractable
needle safety syringe assembly, said method comprising: installing
a flexible polymeric tubular catheter on a syringe coaxially with a
nozzle of the syringe and with a hypodermic needle projecting out
through the nozzle and catheter; puncturing of the skin and vein by
a needle point to gain entry of the needle and the catheter in a
vein; retracting said needle while said catheter remains on the
nozzle for further advance; and maintaining fluid communication
through said catheter and said syringe for monitoring the location
and infusing fluids in the vein; wherein said retracting includes
manually moving said plunger to an over-advanced position in
response to an applied manual force of a predetermined magnitude
for releasing a latch so that a needle holder is released and the
needle is retracted.
114. A method of dispensing a medication needle using a retractable
single use syringe, said method comprising: manually moving a
plunger to an advanced position for dispensing said medication, and
retracting a needle of said syringe; said retracting including
rotating a latch, that extends around at least a part of the
circumference of a cylindrical syringe body, and is attached to
said cylindrical body from an engaged position in which a needle
holder is latched in an advanced position with said needle
extending from said syringe and a disengaged position in which said
needle holder is unlatched to allow a biasing means to move said
needle holder to a retracted position wherein said needle is
retracted within a body of said syringe.
115. The method of claim 114 wherein manually moving the plunger
comprises using a thumb for advancing the plunger to complete the
injection of medicine and wherein said rotating comprises using
said thumb to rotate said latch for retraction of the needle.
116. The method of claim 111 wherein the same hand achieves the
injection of medicine and retraction of the needle.
117. The method of claim 112 wherein the same hand achieves the
injection of medicine and retraction of the needle.
118. The method of claim 113 wherein the same hand achieves the
placement of the catheter and retraction of the needle.
119. The method of claim 114 wherein the same hand achieves the
placement of the catheter and retraction of the needle.
120. A method of intravenous catheter placement using a retractable
needle safety syringe assembly, said method comprising: installing
a flexible polymeric tubular catheter on a syringe coaxially with a
nozzle of the syringe and with a hypodermic needle projecting out
through the nozzle and catheter; puncturing of the skin and vein by
a needle point to gain entry of the needle and the catheter in a
vein; retracting said needle while said catheter remains on the
nozzle for further advance; and maintaining fluid communication
through said catheter and said syringe for monitoring the location
and infusing fluids in the vein; wherein said retracting includes
rotating a latch, that extends around at least a part of the
circumference of a cylindrical syringe body and is attached to said
cylindrical body, from an engaged position in which a needle holder
is latched in an advanced position with said needle extending from
said syringe and a disengaged position in which said needle holder
is unlatched to allow a biasing means to move said needle holder to
a retracted position wherein said needle is retracted within a body
of said syringe.
121. The method of claim 120 wherein the same hand achieves the
placement of the catheter and retraction of the needle.
122. A retractable needle safety syringe assembly, comprising: a
hollow generally cylindrical barrel, with a wider proximal segment
and a distal hollow nozzle communicating with the barrel; a needle
holder having a hypodermic needle mounted at a distal end thereof;
a compression spring wrapped around the needle holder; a plunger
slidably inserted in the barrel, and having an elastomeric piston
at a distal end and a central channel enclosing the spring wrapped
needle holder and needle, and having linear axial mobility in
barrel independently of said spring and said needle holder; a
tubular spring retainer having a distal extension for supporting
said compression spring wrapped around the needle holder and
biasing said needle in a direction for retracting the needle within
the barrel, and a proximal extension plate having a projection that
positively engages with the needle holder in the central channel of
the plunger to maintain it in an advanced position in which a
needle on the distal end of said needle holder projects from a
distal end of said nozzle; the wider barrel segment forming a
distal support shelf for supporting the spring retainer and an
elevated internal ring within the proximal segment of said barrel
for proximally stabilizing the spring retainer; said plunger
advancing the piston to make a surface contact of a piston distal
conical end with a conical interior end of barrel for injecting
medicine through the needle by minimal force applied to said
plunger; said plunger being movable with an additional applied
force to advance distally within a cavity formed in the rubber
piston cavity and so as compress the elastic rubber piston thereby
additionally advancing distally within the barrel, whereby a pair
of plates projecting from the plunger disengage the proximal plate
projecting over the needle holder causing the release and
retraction of the needle holder.
123. A retraction control module for retractable needle safety
syringe, said module comprising: a hollow cylindrical tube with a
distal axial extension forming a central cantilever with a central
through opening, and a proximal eccentric anchoring plate forming
an engagement geometry to engage and anchor a needle holder to the
module; said needle holder having an advanced position in which a
needle on the distal end of said needle holder projects from a
distal end of said syringe, and a retracted position in which said
needle is retracted within said syringe; a helical compressed
spring encircling the needle holder and supported by said axial
extension and the central cantilever with the needle holder and an
attached needle passing through the central through opening of said
cantilever, and within the tube; a plunger compressibly engaged
with a resilient cap passing through said cylindrical tube and
having two parallel walls defining a central open channel that
contact with the eccentric anchoring plate without deflecting said
anchoring plate; said plunger having a distally advanced position
and ramps on said parallel walls which deflect the anchoring plate
radially to disengage the needle holder and cause retraction of the
needle when the plunger is advanced to said distally advanced
position; said needle holder being slidably mounted in said central
open channel of said plunger; said anchoring plate with extension
arising from the opposite surface of the hollow cylinder from said
distal axial estension and engaging with a proximal part of the
needle holder preventing the expansion of said spring.
124. The retraction control module of claim 123 wherein two halves
snap together to complete cylindrical tube.
125. The retraction control module of claim 123 which, when engaged
to a syringe barrel, converts a conventional syringe into a
retractable needle safety syringe.
126. The retraction control module of claim 123 wherein the
cylindrical body is engaged to the barrel mechanically, chemically
bonded or by physical means such as ultrasonic.
127. The retraction control module of claim 123 wheein when the
anchoring plate is engaged with the needle holder, it urges the
said needle holder distally exterior through the nozzle for normal
use while when disengaged the expanded spring of the module urges
the needle and the needle holder inside the barrel.
128. The retraction control module of claim 123 wherein said
cylindrical tube has, on a proximal diameter opposite the anchoring
plate, an extension plate that stabilizes the walls of the plunger
inside the retraction control module.
129. The retraction control module of claim 128 wherein the
extension plate has a detent that locks with a mating plunger
detent on a posterior plunger flange, so as to engage and interlock
the syringe.
130. The retraction control module of claim 123 wherein hydraulic
forces in the syringe do not affect the retraction control module
because it is outside a fluid chamber defined in the syringe.
131. The retraction control module of claim 123 where in the
location of the retraction control module determines the volume of
the medication taken in and injected and the length of the needle
to be retracted.
132. A retraction control module for a retractable needle syringe,
said module comprising: a tubular module defining a cross-sectional
geometry of a closed plane that fits within the barrel of a syringe
by one of a mechanical fit, a chemical bond and an ultrasonic bond
at a desired axial location; said retraction control module having
a central cantilever with a central opening arising from inside and
at a distal surface thereof; wherein said cantilever supports a
compression spring wrapped around a part of a needle holder and
locked between the cantilever and a proximal lateral part of the
needle holder; a plunger with a compressibly engaged elastic cap
and a central channel; a proximal surface of the tubular module
having an anchoring plate juxtaposed to the plunger channel and
having at one end a right angled bend towards the center to
releasably engage a needle holder against the extensile force of a
spring, so as to urge a needle out of the nozzle for a normal
operative mode of the syringe; said needle holder passing through
the opening in the cantilever and having an axial linear mobility
unless restricted by its engagement with the anchor plate of the
said retraction control module or a detent in a proximal end of the
plunger; said plunger having linear axial movements within the
retraction control module, 15 and having triangular projections on
flanges which define the central channel which just contact the
anchoring plate to inject the contents of the barrel, and wherein,
in response to the plunger when forced further, said projections
displace the anchoring plate so as to release the needle holder and
needle.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of priority of U.S.
Provisional Patent Application Ser. No. 60/333,721, filed Nov. 28,
2001.
FIELD OF THE INVENTION
[0002] The present invention generally relates to syringes for use
with hypodermic needles. In particular, the present invention
relates to a needle-syringe assembly which withdraws the sharp
point of the hypodermic needle following, use so as to render it
non-reusable. An over-the-needle (OTN) catheter may also be used
with the syringe assembly of the invention.
BACKGROUND OF THE INVENTION
[0003] A hypodermic needle has many applications in modern
medicine. One application is to fit the hypodermic needle onto a
syringe and to then insert the needle into a person's body for
intra-muscular, subcutaneous, or intravenous injection of
medications. Another application of the hypodermic needle is to
coaxially mount a catheter over a hypodermic needle and to puncture
a vein of a person's body with the needle. Following needle
puncture, the over-the-needle (OTN) catheter is advanced into and
retained in the vein, the needle is removed, and the catheter is
connected to an intravenous line for fluid infusions into the
vein.
[0004] A hypodermic needle entering into a patient's body is
invariably contaminated by the patient's blood and body fluids.
Following use of the needle, the needle presents a risk to
physicians, nurses, and other health care personnel because the
needle might transmit an infection or disease to such personnel if
it were to accidentally puncture them. Thus, health care personnel
are in constant danger of contracting infections and diseases, some
of which may be deadly. Other potential victims of accidental
needle punctures include sanitation workers who later dispose of
garbage containing the hypodermic needle. The diseases which may be
transmitted by a contaminated hypodermic needle include Immune
Deficiency Virus, Hepatitis, Rabies, Kure, Encephalitis, and Arbor
viruses. The outcome of contracting one of these diseases is often
fatal because there are no known cures for any of these diseases.
Often a needle puncture in a person's skin is so trivial that it
remains unrecognized until the person becomes seriously ill.
[0005] Many existing OTN catheters suffer from penetration problems
because of long length needles and unsecured needle supports. In
addition, many existing OTN catheters still present the danger of
causing needle pricks due to ineffective encasement of the
puncturing needles following use.
[0006] The impact of needle stick injuries has shaken the
healthcare industry. Several new products have been introduced and
their disadvantages are now becoming apparent. An inventive
improvement is required to remove these disadvantages.
[0007] The United States Congress has passed "Needle Stick Safety
and Prevention Act (H.R.5178.ENR)". The President has signed the
bill into law that Is effective Apr. 18, 2002. The law, FDA, OSHA,
Center For Disease Control, National Institute for Occupational
Safety and Health and other regulatory bodies have also mandated
and/or recommend several improvements in syringes.
[0008] It will be clear from the reading of the disclosure that the
present invention does possess all the improvements deemed
mandatory and/or recommended by regulatory agencies.
[0009] A number of improvements required and/or recommended by
health care regulatory bodies contained in the present invention
are listed below.
[0010] 1. The syringe as well as retraction mechanism should be
single hand operable, sparing another hand of physician for
additional tasks. [Improved Industry Standard]
[0011] 2. The switches and functional components are inseparable
from the syringe and available in any emergencies. [Improved
Industry Standard]
[0012] 3. Activation of the retraction mechanism must occur from
proximal plunger end. [Improved Industry Standard]
[0013] 4. The worker's hand must remain behind the needle as it is
covered. (FDA guidance on 510(k) Submission March 1995)
[0014] 5. The safety feature must be an integral part of the
device. (FDA guidance on 510(k) Submission March 1995)
[0015] 6. The safety feature remains activated before disassembly
and disposal. (FDA guidance on 510(k) Submission March 1995)
[0016] 7. The safety feature should be simple and should require as
little or no user action or training to use it safely and
effectively. (FDA guidance on 510(k) Submission March 1995)
[0017] 8. The safety feature is an integral part of the device.
National Institute of Occupational Safety and health (NIOSH)
desirable characteristics DHHS (NIOSH) alert. Publication No.
2000-108, November 99
[0018] 9. The device preferably works passively. DHHS (NIOSH)
alert. Publication No. 2000-108, November 99
[0019] 10. The user can easily tell whether the safety feature is
activated. DHHS (NIOSH) alert. Publication No. 2000-108, November
99
[0020] 11. The safety feature cannot be deactivated and remains
protective through disposal DHHS (NIOSH) alert. Publication No.
2000-108, November 99
[0021] 12. The device performs reliably. DHHS (NIOSH) alert.
Publication No. 2000-108, November 99
[0022] 13. The device is easy to use and practical. DHHS (NIOSH)
alert. Publication No. 2000-108, November 99
[0023] 14. The device is safe and effective for patient care. DHHS
(NIOSH) alert. Publication No. 2000-108, November 99.
[0024] 15. Cost reduction by avoiding sharp container requirement
for non-safe syringes Government Regulatory Agencies mandate use of
the "sharp containers" at hospitals, physician offices and clinics
as well as emergency rooms. These containers are strong steel boxes
with a one way window through which used non-safety syringe and
needles are dropped. The sharp protection service is operated by
licensed companies that pick up the contents of the "Sharp
containers" and dispose them at specially run facilities. This
service is expensive and impacts on the cost of health care. Two
safety syringes currently on the market do retract the needles
after use, however the retracted needle and spring freely floats
within the plunger cavity. If by chance the plunger is pulled off
by minimum efforts the potential of needle stick injury does exist.
FDA requires sharp containers for these because there is a chance
of the needle stick injury. It adds to the expense.
[0025] One purpose of inventing the present safety syringe is to
lock the retracted needle securely within the interlocked syringe
itself rather than sharp container and save the expense. It is
essential that the entire syringe must be interlocked and disposed
off in biological recyclable waste to avoid the expense of sharp
container fees. This objective is incorporated in the present
invention
[0026] 16. Premature disablement of devices. Advance of plunger in
the barrel is a normal function of the syringe to inject the
medicine. However in two devices on market retraction of the needle
and disablement of syringe results from advance of the plunger
within the barrel cavity, even before physician has a chance to use
the syringe for patient. The syringe is wasted. The safety
mechanism incorporated in the present invention and procedure of
use avoids this accidental retraction and disablement.
[0027] 17. Low dead space. At the end of the injection, medicine
still remains within the nozzle and the female luer end. The cost
of biotechnology medicines such as Epo, and newer insulins are very
high and wastage is unacceptable. The present invention avoids the
female luer connector that connects hypodermic needle with the
nozzle--the cause of dead space.
[0028] 18. Aerosolization. In certain devices on the market, after
the injection of the medicine and advance of the plunger, a spring
is released and the needle and spring flies back within the
air-filled plunger. When the needle shoots back the air escapes out
through the open needle due to the backward momentum and causes the
fluid/medicine to escape from the needle. The escaping fluid may be
contaminated.
[0029] The FDA has allowed the use of such syringes only for
intra-muscular and subcutaneous application. Further it requires on
use of such syringes that the retraction must be initiated and
completed when the needle of the syringe is still within the body
of the patient.
[0030] In the present invention the proximal end of the needle is
closed and glued to the needle holder. Further the exit and entry
of the fluid occurs at the peripheral wall of the needle, which is
a zero velocity zone during needle retraction, and heavy
construction. Also, the weight of the needle holder arm dampens the
retroactive velocity of the needle. A reactive aerosolization is
therefore not likely to occur, i.e., the present invention avoids
aerosol problems.
[0031] 19. Hydraulic disablement. Robust design of the present
invention prevents disablement of retractable needle syringe that
could result from increased hydraulic pressure inside the
barrel.
[0032] Accordingly, there exists a need for a hypodermic needle
assembly which overcomes the above-noted drawbacks associated with
many existing assemblies.
[0033] The problem of suffering accidental needle punctures is well
recognized. As a result, enormous inventive effort has been devoted
to concealing the sharp needle point of hypodermic needles. Such
efforts are described in the present applicant's U.S. Pat. No.
5,338,311, issued Aug. 16, 1994 and U.S. Pat. No. 6,156,013, issued
Dec. 5, 2000.
[0034] Apart from the above patents, in certain of the syringes
that are in the market, the hypodermic needle is assembled within
the compression spring and installed in the nozzle of the syringe
by a bushing or "O" ring. After injection of the medicine the
bushing is displaced forward by plunger end. The displacement of
the bushing releases the spring and the needle as well as the plug
in the plunger cavity. The retracted spring, hypodermic needle and
plug freely float in the plunger.
[0035] In situations (1) when the plunger is pushed fast before
medicine could escape, (2) When the medicine is viscous and needs
higher gradient to escape through the needle, (3) when the needle
is thin and offers resistance, (4) when there is partial block in
needle or has been inserted in thick tissue, hydraulic force
generated in barrel displaces the bushing causes retraction. This
happens even though plunger is not advanced and medicine is still
in the syringe. The present invention prevents this mishap because
of mechanical continuity and robust design.
SUMMARY OF THE INVENTION
[0036] One aspect of this invention comprises an improved
needle-syringe assembly which provides a simple and reliable
mechanism to retract the needle after it has been used.
[0037] One aspect of the present invention was to identify the
retraction control mechanism from the conventional hypodermic
injection syringe, minimally supplement it with needed components,
and systematically modify existing components of the syringe while
preserving their normal function yet recruiting them to transform
into a precision needle retraction syringe machine. Functional
elements assembled with a spring retainer and plunger become a
retraction control module to be installed in a conventional barrel.
Indirect coupling of a needle holder to the barrel via a "switch"
forms a retraction control system.
[0038] Another aspect of the present invention comprises an
improved needle-syringe assembly which facilitates fabrication, and
reduces the cost, of the assembly.
[0039] Still another aspect of the present invention comprises an
improved needle-syringe assembly which facilitates the operation of
the assembly, particularly when it is desired to retract the needle
prior to disposing of the needle-syringe assembly.
[0040] Another aspect of the present invention comprises an
improved needle-syringe assembly which improves the acceptability
of the assembly by providing an external appearance which is
virtually the same as that of conventional hypodermic needle
assemblies which do not provide for needle retraction.
[0041] Yet another aspect of the invention comprises a
needle-syringe assembly which provides for conventional operation
for normal use, while needle retraction, once voluntarily
activated, is automatic and complete.
[0042] Still another aspect of the invention comprises a
needle-syringe assembly wherein the retracted position of the
needle avoids puncture of the barrel and accidental sticking of
medical staff.
[0043] Other aspects and advantages of the invention will become
apparent upon reading the following detailed description and upon
reference to the accompanying drawings.
[0044] In accordance with one aspect of the present invention, a
syringe assembly, operable in a normal mode and convertible to a
retraction mode, comprises a safety syringe assembly which includes
an elongated, generally cylindrical barrel having a hollow interior
forming a hollow nozzle located at a distal end of said barrel and
opening into the interior of said barrel, a plunger slidably
mounted in said barrel and having a longitudinal cavity, a needle
holder slidably mounted in said longitudinal cavity of said plunger
for movement between an advanced position in which a needle on the
distal end of said needle holder projects from a distal end of said
nozzle and a retracted position in which said needle is retracted
within said barrel, elastic biasing means mounted inside said
barrel and coupled to said needle holder for urging said needle
holder toward its retracted position, and a latch releasably
engageable with said needle holder and movable between a closed
position in which said needle holder is latched to hold said needle
holder in its advanced position against the urging of said biasing
means, and an open position in which said needle holder is
unlatched to allow said biasing means to move said needle holder to
its retracted position.
[0045] In accordance with another aspect of the invention there is
further provided an retractable needle, over-the-needle catheter
and means for releasably securing the catheter to the
above-mentioned safety syringe assembly, as well as modification of
the present invention for a prefilled syringe.
[0046] Other improvements will be apparent after reading the
appended description and claims which constitute their self
supporting disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] In the drawings:
[0048] FIG. 1 is an exploded view of a safety syringe in accordance
with the invention;
[0049] FIG. 2 is an assembled view of the syringe of FIG. 1,
partially in section;
[0050] FIG. 3 is a partial elevation of the syringe of FIGS. 1 and
2;
[0051] FIG. 4 is an elevation, partially in section, of a barrel
portion of the syringe of FIGS. 1 and 2;
[0052] FIG. 5 is a sectional view rotated 90.degree. from the view
of FIG. 4;
[0053] FIG. 6 is a sectional view illustrating assembly of a switch
or latch element with the barrel of FIGS. 4 and 5;
[0054] FIGS. 7 and 8 are an elevation similar to FIG. 5 and an
isometric view showing an alternate embodiment of a barrel;
[0055] FIG. 9 is an elevation similar to FIG. 4 showing an
alternate embodiment of a barrel;
[0056] FIG. 10 is a section through the view of FIG. 9, similar to
the section shown in FIG. 7;
[0057] FIGS. 11 and 12 are respective elevations of a needle holder
rotated respectively 90.degree. from each other;
[0058] FIGS. 13 and 14 are enlarged views of portions of the needle
holder of FIGS. 11 and 12;
[0059] FIGS. 15 and 16 are elevations rotated respectively by
90.degree. from each other, of a plunger element of the syringe of
the invention;
[0060] FIGS. 16a and 16b show an alternate embodiment of the
plunger;
[0061] FIGS. 17 and 19 are two sections through the plunger of
FIGS. 15 and 16;
[0062] FIG. 18 is an enlarged view of a portion of the plunger
shown in FIG. 15;
[0063] FIGS. 20, 21 and 22 are respectively a front elevation, an
end or top view and a side elevation of a spring retainer element
of the syringe assembly of the invention;
[0064] FIGS. 23 and 24 are a side elevation and plan view
respectively of a latch or switch element in accordance with one
embodiment of the invention;
[0065] FIG. 25 is a sectional view of the latch or switch element
of FIGS. 23 and 24 assembled with a barrel;
[0066] FIG. 26 is a partial side elevation of a barrel showing the
latch or switch element of FIGS. 23 and 24 assembled therewith;
[0067] FIGS. 27 and 28 are respective sectional views, similar to
FIG. 25 showing the assembled syringe assembly with the latch or
switch element respectively in a locked and unlocked positions;
[0068] FIGS. 29 and 30 are respective elevation and plan views of a
latch or switch element in accordance with another embodiment of
the invention;
[0069] FIGS. 31, 31a, 31b and 31c are elevation side and top views
of an embodiment of a latch or switch similar to the embodiment of
FIGS. 29 and 30;
[0070] FIG. 32 is a partial sectional view showing assembly of the
switch element of FIGS. 29-31 with a barrel;
[0071] FIGS. 33 and 34 are partial sectional views illustrating
locking and unlocking positions of the switch or latch of FIGS.
29-31 with respect to activating or unlocking elements on a plunger
of the type shown in FIGS. 15 and 16;
[0072] FIGS. 35 and 36 are respective side and top views showing a
switch or latch element in accordance with yet another
embodiment;
[0073] FIG. 37 is a partial sectional view showing a portion of the
latch element of FIGS. 35 and 36 assembled with a spring retainer
element of the type shown in FIG. 20;
[0074] FIGS. 38 and 39 are respective sectional views showing the
latch or switch element of FIGS. 35 and 36 assembled with a syringe
assembly and respectively in latched and unlatched positions;
[0075] FIGS. 40 and 41 are partial side views, partially in
section, illustrating further the operation of the latch element of
FIGS. 35 and 36;
[0076] FIGS. 42-47 illustrate a sequence of assembly of the syringe
assembly of the invention;
[0077] FIGS. 48 and 49 illustrate a needle and over-the-needle
catheter for use in an alternate embodiment of the syringe of the
invention for placement of an over-the-needle (OTN) catheter;
[0078] FIGS. 50-54 illustrate a sequence of operation utilizing the
syringe of the invention to place an over-the-needle catheter with
respect to a vein of a patient;
[0079] FIG. 55 is an isometric view of another embodiment of a
spring retainer;
[0080] FIG. 56 is a side elevation of the spring retainer of FIG.
55;
[0081] FIG. 57 is a partial front elevation of the spring retainer
of FIG. 55;
[0082] FIG. 58 is an isometric view of a second piece of the spring
retainer of FIGS. 55-57;
[0083] FIG. 59 is a side elevation of the spring retainer portion
of FIG. 58;
[0084] FIG. 60 is a side elevation of another embodiment of a
needle holder used in connection with the spring retainer of FIGS.
55-59;
[0085] FIG. 61 is an isometric view of the needle holder of FIG.
60;
[0086] FIG. 62 is an enlarged top view of the spring retainer of
FIGS. 60 and 61;
[0087] FIG. 63 is a top view of another embodiment of a barrel;
[0088] FIG. 64 is a partial view of an assembled syringe, partially
broken away, illustrating assembly of the components of FIGS. 55-63
therewith;
[0089] FIG. 65 is a front elevation of another embodiment of a
spring retainer element portion which may be coupled with the
second retainer portion shown in FIGS. 58 and 59 to form a spring
retainer element in accordance with another embodiment of the
invention;
[0090] FIG. 66 is a rear elevation of the spring retainer element
of FIG. 65;
[0091] FIG. 67 is a side elevation of the spring retainer element
of FIGS. 65 and 66;
[0092] FIG. 68 is a top view of another embodiment of a barrel;
[0093] FIG. 69 is a side elevation of another embodiment of a
needle holder used in connection with the spring retainer element
of FIGS. 65-67;
[0094] FIG. 70 is an enlarged top view of the needle holder of FIG.
68;
[0095] FIG. 71 is a partial view of an assembled syringe, similar
to FIG. 64 showing the spring retainer and needle holder components
illustrated in FIGS. 65-70;
[0096] FIG. 72 shows another embodiment of a plunger; and
[0097] FIGS. 73-77 show another embodiment of a plunger for a
pre-filled syringe.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
[0098] While the invention is susceptible to various modifications
and alternative forms, specific embodiments thereof have been shown
by way of example in the drawings and will herein be described in
detail. It should be understood, however, that it is not intended
to limit the invention to the particular forms disclosed, but on
the contrary, the intention is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope
of the invention as defined by the appended claims.
[0099] Several different embodiments of the invention, each with
its own unique features and alternate embodiments, are described.
Permutations and combinations of these features will, however, lead
to further embodiments.
[0100] Turning now to the drawings, FIGS. 1 and 2 illustrate a
needle-syringe assembly, including a barrel 10, a plunger 11, a
hollow resilient (rubber) plunger cap 12, a hypodermic needle 13,
and a needle holder 14. The barrel 10 is a hollow cylinder which
terminates in a hollow tapered nozzle 15 at the distal end thereof,
and has a slightly enlarged outer diameter portion 16 extending
from about midway along its axial length to its proximal end. The
interior of the nozzle 15 communicates with the hollow interior of
the tubular body portion of the barrel 10. The barrel has outwardly
extending flanges 17 on the proximal segment 16 of the barrel 10
which facilitate gripping of the barrel with the user's fingers
when it is desired to move the plunger 11 relative to the barrel 10
linearly for normal use. The flange may be annular or oblong. A
retracting means, such as an elastic or resilient biasing means,
here illustrated as a compression spring 300 is mounted inside the
barrel 10 and operatively contacts the needle holder 14 for urging
the needle holder toward its retracted position, that is a position
in which the needle 13 is retracted completely within the barrel 10
(see e.g., FIGS. 46-47).
[0101] In the embodiment illustrated in FIGS. 1 and 2, the elastic
biasing means takes the form of an elongate compression spring 300
of relatively small diameter which fits about the outer
circumference of the needle holder 14. This spring 300 is of such a
diameter that it also inter-fits within an elongated channel or
cavity 33 of the plunger 11. However, the elastic biasing means or
spring may take a number of other forms without departing from the
invention.
[0102] On one side of the barrel 10 and distal to the flanges 17,
there are two square molded raised detents 100 intended to lock a
cylindrical switch 308 (described later) between these detents and
the flanges. During installation, recesses 426 on the switch 308
(see FIG. 6) clear the detents and the switch abuts the flange 17.
A 180-degree rotation of the switch causes it to lock against the
square detents. However, engagement of the needle holder arm 32
with the switch 308 prevents its rotation beyond 12-15 degrees.
Once assembled, the switch is inseparable from the syringe, a
safety requirement for all medical devices. As mentioned above, the
proximal segment 16 of the barrel 10 beyond the flanges 17 has a
somewhat larger diameter. The differential of internal diameters
creates a structural shelf 110 that supports a cylindrical spring
retainer 302 which can be a single piece or in two parts 302a,
302b. An elevated ring is molded within the barrel cavity to
prevent proximal axial displacement of the spring retainer.
[0103] On the surface of the proximal segment 16 of barrel (see
also FIGS. 4-8), opposite to the square detents 100 there is an
open or closed channel or track 19 for locking the needle holder
arm 32 (e.g., by switch 308) at its distal end and a serving as
retracting track or guide once the needle holder 14 is released.
The proximal segment 16 of the barrel 10 may be about one and one
half inch in length for storing the needle holder with attached
hypodermic needle in fully retracted, locked and secured in
straight position within the plunger channel, in the center of the
syringe. The distal part of the proximal chamber 16 also contains
the spring retainer and spring. The needle holder, in turn is
releasably locked to the barrel via the switch 308. The needle
protector cap 200 provides an air and water tight seal at the
nozzle before use, while after use it will prevent leakage of any
contaminant, and the entire syringe can be disposed of in
biological waste. The cap 200 and nozzle may have interlocking luer
tapers or, even threads to secure the caps, for example, for a
pre-filled syringe.
[0104] In an alternate barrel embodiment (see FIGS. 7-10), the slot
that permits the retraction of the needle holder arm proximally is
covered by an increased diameter wall segment 29, which merges with
the barrel circumference at its margins. The distal end of the wall
segment 29 may be open to permit engagement of the needle holder
arm 32 by the latch/switch 308, or closed, for use with an internal
latch/switch described later. Such a "covered" design may be
advantageous because it can be molded by straight pull tooling.
This reduces the cost of tool by avoiding complex side action
slides (i.e., to mold the track 19), and increasing the density of
the parts in the mold. The barrel without the exposed track 19 has
a more esthetic appearance and is also more hygienic. Further, the
distal end of the wall 29 if open, is covered by the switch 308 or
408, which provides a uniform surface to the syringe.
[0105] This alternate design (FIGS. 7-10) is otherwise similar to
the above-described embodiment (FIGS. 4-8) of the barrel.
[0106] The outer surface of the barrel 10 may contain graduations
114 (FIG. 2) indicating the volume level of fluid in the barrel.
These graduations take into account the volume of the internal
components such as the needle holder 14.
[0107] The proximal end of the plunger 11 forms a knob 20 that can
be grasped by a user to effect linear movement of the plunger 11
relative to the barrel 10. The periphery of the knob 20 can be
serrated or engraved to prevent slipping of the knob during the use
of the plunger. The distal end of the plunger 11 forms a head 21 to
mount the hollow rubber plunger cap 12 thereto. The outside
diameter of the resilient cap 12 is reduced in the central portion
so that the cap engages the inside wall of the barrel 10 only at
the pliable margins of the ends of the cap. The diameter of the
engaging end portions of the cap 12 is slightly larger than the
inside diameter of the barrel 10 so that the cap presses firmly
against the inside wall of the barrel to form an air-tight and
liquid-tight seal at the cap/barrel interface. The inner margins of
the cap 12 make a similar tight contact with the outer surface of
the needle holder 14. The distal end 22 of the cap 12 is conical to
conform to the conical distal end 23 of the inside surface of the
barrel 10 when the plunger 11 is fully advanced within the barrel.
This reduces the dead space and assures complete emptying of
medicine into the patient. The outer wall of the cap 12 may be
thickened somewhat to prevent its collapse during the in barrel
assembly process (described later).
[0108] The head 21 of the plunger 11 is configured to fit within
the hollow plunger cap 12. With the cap 12 locked onto the head 21
of the plunger, the flat proximal end 24 of the cap abuts the flat
surface of a circular disc 25 at the base of the plunger head 21.
The disc 25 transmits advancing force to the rubber cap 12. Due to
the air-tight and liquid-tight seal between the plunger cap 12 and
the barrel 10, as well as the needle holder 14, advancing movement
of the plunger 11 inside the barrel 10 creates pressure in the
interior of the barrel between the plunger cap and the distal end
of the barrel. Similarly, retracting movement of the plunger 11
creates a vacuum in that portion of the barrel interior.
[0109] The distal end of the plunger head 21 is flat or
frustoconical while the mating inner surface of the cap 12 is
conical with space for a lose fit. This mismatch is intentional and
functional. The significance is described later in disclosure.
[0110] Referring to FIGS. 11-14, the hypodermic needle 13 is
mounted on the distal end of the elongated needle holder 14, which
is detachably interlocked to the barrel 10 (in channel or track
19). Prior to use of the needle-syringe assembly, the needle 13 is
covered by a protective cap 200 mounted on the nozzle 15 which
prevents needle pricks, preserves sterility prior to use, and
preserves the barrel pneumatic volume. In addition, the nozzle may
have an external or male luer taper that mates with an internal or
female luer taper of the protective cap. When engaged they form
strong locking contact to prevent accidental separation of parts
during transport or handling. The luer lock also creates an air and
water tight seal that prevents air from the barrel from escaping
and maintaining a positive air pressure within the syringe barrel.
Positive air pressure in the syringe barrel prevents intentional as
well as accidental advance of the plunger in barrel. This assures
that the retraction mechanism will not be activated until the user
removes the protective cap from nozzle. The medicine aspirated in
the syringe before expelling the air also assures that the plunger
does not advance to the point of causing retraction. If these
instructions are followed there is no chance of
premature/accidental retraction of the hypodermic needle and
disablement of the syringe.
[0111] Both the needle 13 and the distal portion of the needle
holder 14 are hollow, and the interior of the hollow needle 13
communicates with the interior of the hollow distal portion of the
needle holder 14. The needle holder 14 further communicates with
the interior of the barrel 10 through an aperture 26 which extends
through the side wall of a hollow portion of the needle holder 14
at a distal end thereof (FIG. 14). Prior to and during use of the
needle-syringe assembly for injection of medicine (hereafter
referred to as "normal use"), the aperture 26 is positioned at the
base of the barrel nozzle 15, sometimes within a small cylindrical
cavity (not shown). The side aperture 26 permits medicine to enter
or exit from the barrel 10 via the needle holder 14 and the needle
13. The proximal end of needle 13 is not directly open to air and
therefore the needle does not have an "open" end on retraction, as
in some prior art arrangements. Instead it is glued within the
cavity of the needle holder, and fluid transport occurs through the
side hole 26 at a boundary zone A small rubber O-ring 202 is
located against a distal shoulder 27 of the barrel interior (see
FIGS. 3-4) to promote sealing engagement with a distal end 41 of
the needle holder 14 when the distal end 41 is stepped down as
shown in FIG. 14 to provide a shoulder. A set of luer tapers may be
used as an alternate form of sealing.
[0112] During normal use of the needle-syringe assembly, the needle
holder 14 is directly or indirectly locked to the barrel 10 (in
track 19), and the plunger 11 with its cap 12 is free to slide
longitudinally back and forth along the needle holder within the
barrel. In one embodiment, (see FIGS. 11-13) the needle holder 14
includes a generally L-shaped rod having a longitudinal body
portion 30 extending to the aperture 26 and hollow from the
aperture 26 to its distal end, and a lateral arm 32, supported on
an enlarged, shaped end part 35 of the needle holder 14, for
extending radially across the barrel 10 and through the track 19,
at a proximal end of the body 30.
[0113] The lateral arm 32 of the needle holder 14 may also include
an enlarged diameter circumferential shoulder surface 35 for
engagement with outermost surfaces of plunger ribs 60, 62
(described below) which form the channel 33, so as to position the
needle holder 14 at the proper depth with respect to the channel
33.
[0114] A proximal part 36 of the straight portion 30 of the needle
holder has a larger diameter for supporting the compressed length
of the spring 300 within a spring retainer 302 (described below).
The lateral arm 32 is also heavier to resist the vertical force of
the spring 300 as well as to dampen the peak velocity of the
retraction when released.
[0115] The end portion 35 of the needle holder 14 has a rectangular
recess 31 on the side as shown in FIGS. 12 and 13. This recess 31
locks with a detent 75 within the plunger channel 33 (see FIGS. 14
and 17) when the needle holder is retracted. This interlocks the
syringe assembly in a safe position. In addition, the expansion of
the spring also maintains the needle holder at this location.
[0116] Referring also to FIGS. 15-19, to permit relative sliding
movement between the plunger 11 and the needle holder 14 in the
longitudinal direction, the needle holder is mounted in a
longitudinal cavity or channel 33 formed as an integral part of the
plunger 11. Multiple pairs of resilient retaining elements or
detents (not shown) project toward each other from the opposed
walls of the channel 33 to retain the needle holder 14 within the
channel.
[0117] Referring also to FIG. 19, the plunger 11 will be seen to
have a plurality of ribs. A first pair of these ribs 60, 62 define
the longitudinal channel 33 for receiving the needle holder 14 as
described above. A single rib 64 projects diametrically oppositely
of these ribs 60 and 62, it forces the needle holder arm 32 through
the track 19 and assures stable engagement and retraction. A
further pair of diametrically oppositely extending ribs 66 and 68
are formed in a plane at right angles to the ribs 60, 62 and 64. In
the embodiment of FIGS. 16a-16b, in the proximal one and one half
portion of the plunger, the three ribs 64a, 66a, 68a, collectively
extend transversely across the interior of the barrel 10 so as to
help maintain the circular configuration of the barrel, for
example, to counteract any weakness caused by the track 19. This
also helps to ensure the locking engagement of the lateral arm 32
with the track 19.
[0118] The plunger 11 is the sole moving part of the syringe in
normal operation, and makes contact with the fluid chamber defined
in the barrel via the rubber stopper 12. The linear movements of
the plunger within the barrel determine the amount of the fluid
taken in and injected into the patient. These movements and
location of the plunger can therefore be mechanically indexed to
the functional outcome of the syringe, retraction of the needle
holder as well as disablement of the syringe. Two triangular
projections 70 and 72 on the margins of flanges 60 and 62 are
designed and located to interact with a switching mechanism or
"instant switch" as explained later.
[0119] In the illustrated embodiment, the opposed walls or ribs 60,
62 of the channel 33 extend toward the inside wall of the barrel 10
(see FIG. 19), thereby constraining the lateral arm 32 of the
needle holder against any angular or rotational displacement
relative to the plunger 11. That is, the plunger 11 and the needle
holder 14 can rotate if ever only in unison with each other,
although they may move freely independently of each other in the
longitudinal direction to permit needle restriction after normal
use. At the proximal end of the channel 33, a locking detent 75
locks the end portion 35 of the needle holder and plunger together
to prevent relative longitudinal movement after retraction of the
needle holder 14 is complete.
[0120] In the illustrated embodiment, the proximal end of the
needle holder 14 is directly or indirectly, locked to the barrel
10, via the lateral arm 32. This arm 32 extends radially beyond the
plunger channel 33 and fits into the track 19 in the barrel 10. The
arm 32 can be locked to the barrel 10 at the distal end of the
track 19 and, when so locked, permits only reciprocal linear
movement of the plunger 11, to create vacuum to withdraw medication
and pressure to deliver medication to the patient via the
hypodermic needle 13. When the needle holder recess 31 is locked in
the plunger detent 75, following use, the entire assembly is
interlocked and inoperative. During normal use, the needle holder
holds the needle completely advanced or projecting from the nozzle
15 of the barrel 10.
[0121] When fully expanded, the compression spring 300 guarantees
full retraction of the hypodermic needle 13 and needle holder 14 as
well as subsequent maintenance of the needle holder 14 in the
retracted state. The retraction force interlocks the needle holder
detent 31 with the plunger detent 75 (FIG. 7) as well as plunger
arm 32 with the barrel track 19. This renders the syringe
components totally interlocked and inoperative.
[0122] The spring 300 is supported on a robust foundation provided
by a spring retainer 302 shown in FIGS. 1 and 20-22. The spring
retainer, which may be either unitary 302 or two parts (302a and
302b), is installed in the barrel at the shelf like projection 110
defined by the proximal segment 16 of the barrel 10. Mating detents
304, 306 provided on the contacting surfaces of barrel 10 and
spring retainer 302 restricts rotary movements of spring retainer
302 inside the barrel 10. Proximally, an elevated ring 120 (see
FIG. 5) molded within the barrel just above the margins of the
spring retainer 302 securely locks it in place, once the spring
retainer 302 has been axially advanced past the ring 120 during
assembly. A distal axial extension 303 of the spring retainer 302
holds the spring 300 at the margins at one end thereof while
permitting the needle holder 14 to pass through a central hole 310.
The spring 300 is retained in compressed state by releasably
locking the needle holder arm 32, via the switch (e.g., 308) to the
barrel 10. The opening 310 of the spring retainer 302, the spring
300 and the needle holder 14 are concentric with the plunger
channel 33 and with the axis of the barrel cavity.
[0123] Additional features of spring retainer 302 include a
proximal projection 312 which extends along the inner surface of
the barrel 10 and provides mechanical support. This minimizes the
play with the barrel and holds the needle holder tightly locked
within the barrel.
[0124] As mentioned above, a switch or latching means or mechanism
308 controls the position of the needle holder 14 relative to the
barrel 10 for presenting the needle either fully advanced or fully
retracted with respect to the barrel. In the embodiment shown in
FIGS. 1, 2 and 6, the latching mechanism 308 takes one form.
However, other equivalent forms may be used without departing from
the invention, some of which are further described hereinbelow. In
the embodiment shown in FIGS. 1 and 2, the latching means or switch
comprises a needle holder locking element 308, having an aperture
310 which inter-fits about a free end portion of the radially
projecting arm 32 of the needle holder 14 which projects outwardly
of the track 19 in the barrel 10, as described above.
[0125] A number of regulatory bodies require or recommend that in
the safety syringe devices, the switch is inseparable from the
syringe. In general, these requirements or recommendations state
that the functional attachments of a medical device which alters
the functions of the device such as clamps, switches etc. should be
inseparable from the device. These switches or other attachments
must move and work, but they should not be removable. In the
present invention, the ring switch as well as the barrel where the
switch is installed were designed to comply with these medical
device standards and regulations.
[0126] Referring also to FIGS. 23-28, the switch 308 comprises a
closed cylindrical ring with an internal diameter which interfits
about the outer diameter of the proximal portion 16 of the barrel.
A small lock-release lever 320 is molded on the outer surface of an
outwardly projecting portion 322 which has an inward projection 323
to engage and lock the needle holder arm 32 that projects out from
the track 19. Needle holder arm 32 has only linear mobility in the
track 19 along the axis of the syringe. The switch holds the needle
holder arm 32 in position with the spring in a compressed state.
Further, the switch 308 can not be displaced or rotated because it
is engaged with needle holder arm 32 exiting from the slot on the
barrel. The switch lever 320 can rotate to disengage the needle
holder by the flip of the thumb of the same hand that is also
holding the syringe. The switch completely encircles the barrel
between the flanges 17 and the switch retainers-square detents 100
so as to lock the linear movement of the switch on barrel When
engaged It can only rotate one way 15-20 degrees to release the
needle holder. It has no other mobility and can't go anywhere. The
switch 308 is inseparable from the syringe until the syringe itself
is disabled.
[0127] The installation of the switch is as follows. Two slots or
recesses 324 and 326 axially slide over the square detents 100
molded on barrel wall for assembly. The switch is inserted on the
barrel from the nozzle side (distal end) so that the square switch
detents 100 on the barrel are negotiated through the recesses 324
and 326 of the ring switch. Once the recesses are negotiated, the
switch makes a contact with the flange 17. At this time the switch
308 is rotated 180 degrees to engage and lock with the arm 32 of
the needle holder and therefore with the barrel (FIG. 24). A small
detent 325 of the switch 308 engages the lateral arm 32 and limits
switch rotation to one direction. The square detents 100 are now
locked against switch 308, locking the switch 308 in place between
these detents 100 and flange 17, since the recesses 324, 326 are
now moved to a diametrically opposite location (see FIG. 25). Now,
only the user can voluntarily rotate the switch lever 320, 15-20
degrees of rotation one way to retract and disable the syringe by
just a flip of thumb of the same hand that is also holding the
syringe. This causes retraction of needle holder, by aligning one
of the slots 324, 326 (326 in the illustrated embodiments in FIG.
28) with the lateral arm 32 and disables the syringe.
[0128] The ring switch 308 is, therefore, actuated only upon a
conscious decision and voluntary effort on the part of the user to
engage and rotate lever 320. This avoids accidents, and reduces
chance factors in retraction and disablement of the syringe.
[0129] Two other embodiments (FIGS. 29-34 and 35-38) of the
invention are provided with an improved "instant" switch. Operation
of this switch requires that contents of barrel are completely
injected and that a slight additional push is given on the plunger
to release needle holder and initiate retraction, and thereupon to
interlock and disable the syringe. This requires some action of
operator, but can be called "involuntary," in that it does not
require the operator to engage or manipulate any additional
elements but only to press the plunger a bit further after
completing the injection and withdrawing the needle from the
patient.
[0130] During injection, the plunger 11 is the sole moving part of
the syringe and makes contact with the fluid chamber 27 via the
rubber stopper 12. The linear movements of the plunger within the
barrel determine the amount of the fluid taken in and injected into
the patient. These movements and location of the plunger can
therefore be mechanically indexed to the retraction of the needle
holder as well as disablement of the syringe. The two projections
70 and 72 on the margins of flanges 60 and 62 as shown in FIGS.
15-17 are precisely designed and located. They interact with the
switching mechanism of the "instant" switch as explained below.
[0131] The principle of the instant switch is based on the linear
indexing of the plunger advance within the barrel that is
proportioned with the force applied to the plunger head by the
operator's thumb. At a normal fluid injection force of a fraction
of PSI the distal circular plate 25 pushes the rubber piston to the
end of the barrel and injects the contained medicine via needle and
one limit of the plunger advance is reached at this force. The
barrel is completely emptied but it does nothing to the switching
mechanism. The design of the present invention includes a flat
surface 21 of the plunger end that is placed within the conical
cavity 24 of the rubber piston 12 creating an empty or mismatched
space. It also selects a situation specific compressible resilient
rubber piston. These elements together provide an additional range
for the plunger to advance within the barrel at a higher
compression force-PSI. This additional travel of the plunger within
the barrel creates a contact between the plunger ramps 70, 72 with
corresponding parts of the switch resulting in the release of the
instant switch and release of the needle holder and retraction of
the hypodermic needle inside the barrel. This mechanism can be
further fine tuned by adjusting the internal diameter of the distal
end of the barrel, which will increase the force required to
advance the plunger, or incorporating an internal ring or another
stop or detent surface (not shown) in the barrel that will alert
the operator of the peak force and imminent retraction moment. In
addition placing a spring between the plunger plate and the cavity
of the resilient cap will also predictably alter the linear length
of plunger advance and improve the efficacy of the switch.
[0132] Referring to FIGS. 29-34, the "instant" switch 408 comprises
a cylindrical ring, having an open circumferential portion, that
partially encircles the barrel 10 just distal to the flanges 17 and
proximal to the square detents 100 and holds the arm 32 of the
needle holder in place in the distal end of the track 19, anchored
to the barrel 10 under its distal margin. This location axially
locks the switch to the barrel 10 and prevents its linear movement
along the axis of the barrel 10. The only movement that is possible
is the radial displacement of the switch away from the barrel 10,
solely because the switch has an opening 410 in its circumference.
However the resilient material or memory of the switch 408 normally
keeps it in contact with the barrel. In a modified form (FIGS.
31a-c), the switch 408a may be semi-cylindrical and have inwardly
projecting detents 412 and 414 that engage slots 416, 418 on the
flanges 17 of the barrel 10. This prevents rotation and helps to
retain the switch on the barrel.
[0133] The switch 408 (408a) has two ramp-like projections 420
(420a) and 422 (422a) which extend from its inner surface and enter
the barrel 10 through two windows 424 and 426 in barrel outer wall.
The windows also permits projections 420, 422 (420a, 422a) of the
instant switch 408 (408a) to make a contact with the ramps 70-72,
located on the plunger flanges 60 62. The windows are ultimately
and totally covered by the switches installed on the barrel at this
location as is the open channel underneath. The projections 420,
422 (420a, 422a) have angled edges and juxtapose against the
identical angular ramps 70 and 72 projecting from the plunger
plates 60-62 when the plunger is fully advanced. The angles on the
two sets of projections/ramps are identical but face in opposite in
direction. During normal operation, these parts 420, 422 (420a,
422a) and 70,72 have no contact with each other. It is only when
the medicine is fully injected in the patient and the plunger is
further advanced, that the parts 420, 422 and 70, 72 start making
contact. Further distal linear movement of the plunger results in a
radial outward movement of the switch 408 (408a) that results in
the release of the needle holder arm 32 that it was locking under
its distal margin (see FIGS. 33 and 34).
[0134] Summarizing the above, movement of the switch 408 (408a)
away from barrel 10 releases the needle holder 32 instantly and
effects the retraction of the needle. The linear advance of the
plunger in the barrel causes the linear movement of the plunger to
be transformed into the radial movement of the switch 408 (408a)
for releasing the needle holder (see FIG. 34). A normal advance of
plunger 11 causes the plate 25 to push the rubber stopper 12
distally to make contact with the barrel cone 23 and the entire
medicine is injected in the patient. An additional push on the
plunger head 20 further advances the flat plunger end into the
conical cavity of the rubber piston. The pressure squeezes the
elastic rubber piston 12 and permits the further advance of plunger
and consequently the ramps or plates 70, 72 contact the switch and
actuate the "instant" switch 408 (408a) for retraction and release
of needle holder as well as disablement of the syringe as described
above.
[0135] In one example, with a 3cc syringe constructed as described
above and with an "instant" switch 408 a terminal 6.5 PSI force on
the plunger head caused displacement of plunger head within the
rubber stopper as well as some compression of rubber stopper to
generate 0.040 inch distal displacement of the plunger ramps 70 and
72. This displacement in turn radially displaces the "instant"
switch by 0.040 inch and releases the needle holder arms to retract
the needle holder as well as lock it to barrel and disable the
syringe. These results depend on the size and length of the
syringe, elasticity and durometer of the rubber piston, durometer
of the plastic polymers and amount of the force exerted on the
plunger knob as well as environmental/temperature variations which
affect rigidity of polymers.
[0136] Referring to FIGS. 35-39, another embodiment of an "instant
switch" 508 comprises two thin flat plates 520, 522 which are
connected by a bridge 524. A flat projection 526 extends from the
bridge in a direction opposite plates 520, 522 and terminates in a
hook-like extension 540 which projects out through a slot 515 (see
FIG. 20) molded in the margin of the spring retainer 302 (FIG. 27)
inside the barrel 10. The flat projection 56 can move only in the
radial direction. The flat plates 520, 522 connected by the bridge
524 are assembled on the outside of the plunger plates 60-62. The
bridge 524 has triangular recesses 530, 532 that come in contact
with the triangular projections 70 and 72 on the plunger flanges 60
and 62. The plunger moves freely linearly between these flat
plates. The flat projection 526 from the bridge passes under the
needle holder arm 32, exits out of the barrel 10 and the hook-like
extension or L-shaped lip 540 extending from the projection 526
turns back to engage the needle holder arm 32 at the distal end of
the track 19 (FIG. 40). An additional slot (not shown) in the
barrel 10 is provided for this purpose. This essentially locks the
needle holder arm to the barrel via the spring retainer.
[0137] A displacement of the flat plate 524 out of the barrel track
19 by linear movement of plunger distally, releases the needle
holder arm 32 and retracts the hypodermic needle 13 (and needle
holder 14) in plunger channel 33. In the normal operating position,
the plunger moves within the switch. When the entire medicine is
injected and a final push is given to the plunger which advances
the resilient cap 12 as well as compresses it. Triangular
projections 70 & 72 of the plunger engage the recesses 530, 532
and causes movement of the switch 508 so as to release the needle
holder arm 32 and cause retraction of hypodermic needle by the
spring 300. A formed wire can replace the projecting flat plate 526
and lip 540. All that is required is a structure that can hold the
needle holder against the spring force and anchor it to the barrel
and be actuated by the plunger movement as described above.
[0138] Since the switch 508 is located inside the syringe there is
no question of its separation from the device and therefore
complies with regulatory requirements and/or recommendations. Those
skilled in the art may device other specific switch constructions
for accomplishing their goals without departing from the
invention.
[0139] Each of the above-described switch arrangements accomplishes
the above-stated objectives, as well as being non-removable. In
this regard, when the latch or ring 308 is used to retract the
needle holder, the plunger can be in any desired longitudinal
position. For example, the plunger can be fully advanced, fully
retracted, or at any intermediate position. This is advantageous
because it might be desired to retract the needle after only a
portion of a dose of medication has been injected into the patient,
or it might be desired to retain all or a portion of a blood sample
withdrawn from a patient within the syringe. With respect to the
instant switches the plunger must be fully advanced to empty the
syringe before the retraction mechanism is activated. To prevent
the leakage of any fluid contained within the syringe at the time
the needle is retracted, a latex seal (not shown) may be provided
at the end of the nozzle 15. Also, the plunger cap 12 may be
provided with a slit valve that engages the needle and prevents
leakage. The nozzle also can be capped because the hypodermic
needle is locked within the syringe. This retractable needle safety
syringe is supplied sterile and ready to use.
[0140] During normal use of the needle-syringe assembly, the barrel
10 and the needle holder 14 are held stationary, and the plunger 11
is free to move axially relative to both the barrel 10 and the
needle holder 14. Advancing movement of the plunger 11 is limited
by contact of the plunger cap 12 with the end wall 23 of the barrel
10. The needle holder 14 is releasably locked to the barrel 10 by
the locking engagement of the lateral arm 32 to the wall of the
barrel by a latch such as the latch 308. Also, when used, the
locking luer taper releasably locks the needle holder 14 to the
barrel 10. The plunger 11 is also free to move longitudinally
relative to the needle holder 14, because the needle holder is not
locked to the plunger in that direction. However, the locking of
the lateral arm 32 by the latch mechanism at the barrel wall,
prevents rotation of the plunger. As long as the lateral arm 32 of
the needle holder is locked to the barrel wall, the needle-syringe
assembly is in its normal operating mode.
[0141] Following normal use of the needle-syringe assembly, the
needle 13 can be retracted into the plunger 11 and the barrel 10.
This requires axial movement of the needle holder 14 within the
barrel 10 toward the proximal end thereof, which in turn requires
that the needle holder 14 be unlocked for movement, under the
influence of the biasing or retracting means such as spring 300,
within the channel. Thus, to initiate retraction of the needle
holder 14, the arm 32 is unlocked by releasing the latching
mechanism 308, 408 or 508.
[0142] The illustrative syringe need not be any longer than a
conventional syringe because conventional syringes are made longer
than required to provide more than the desired fluid volume, so as
to avoid inadvertent withdrawal of the plunger and the resultant
spillage of the syringe contents. The extra plunger barrel length
to accommodate the user's fingers in the space between the plunger
knob and the finger flanges contributes to excess length in
conventional syringes. In the present invention, the extended
barrel length is used to lock and store the retracted needle holder
and the entire needle.
[0143] FIG. 2 illustrates the assembled syringe and needle assembly
with the cap 200 as it might be provided for use.
[0144] To operate the needle-syringe assembly, the protective cap
200 is removed from the needle 13, and the required amount of
medication is aspirated into the barrel 10 without advancing the
plunger. Air bubbles if any are removed and quantity of medicine is
adjusted. Next, the injection site on the body of a patient is
determined and the skin is cleaned with an antiseptic solution.
Following percutaneous entry of the needle into the patient,
location of the needle tip in the vein is confirmed by aspirating a
small amount of blood into the transparent barrel 10. The plunger
11 is then advanced to inject the medication from the barrel 10
into the vein. After the medication is administered, the needle 13
is withdrawn from the patient, the latch mechanism 308 (408, 508)
is released and the spring 300 or other retracting means retracts
the needle holder 14 and the needle 13 and locks the needle holder
in the plunger detent 75. With the needle 13 completely retracted
inside the barrel 10, all the components of the syringe are
automatically interlocked and non-reusable, and the needle-syringe
assembly can be safely discarded in its entirety. The cap 200 can
be replaced to prevent leakage of any remaining fluid within the
barrel 10.
[0145] It can be seen from the foregoing description that the
needle-syringe assembly performs all the conventional functions of
injection syringes and yet, upon completion of injection, the
hypodermic needle 13 is concealed within the barrel 10. The
needle-syringe assembly with switch 308 can receive and dispense
medications any number of times for a given patient by reciprocal
longitudinal movement of the plunger 11 within the barrel 10.
However, once the latch is released it cannot be reused.
[0146] The needle-syringe assembly of this invention is easy to
manufacture, cost effective, and easy to use in the field. The
parts can all be made by conventional plastic molding and using
readily available medical grade stainless steel needles and
compression springs. The plastic parts are made by injection
molding of medical grade, gamma stable polymers such as
polypropylene. The needle holder and spring retainer that require
higher strength are molded from polycarbonate. The plunger seal or
cap and "O" ring can be molded from non latex thermoplastics
synthetic elastomers or silicones. The switches that require smooth
friction free movements is made from HDPE. Of course the material
selection is guided by the strength and functional requirement of
components. The disclosed materials can be substituted by alternate
or improved compounds that may or may not be presently available.
The needle is glued by using ultraviolet cured adhesives. Syringes
are assembled and packaged in a clean room and sterilized by gamma
radiation.
[0147] While the drawings of components and description, for
simplicity, show a syringe with central nozzle, the axis of all the
components can be shifted to generate a syringe with an eccentric
nozzle without altering the concepts or components. Likewise, the
cross-sectional shape of syringe components can also be modified
without deviating from inventive description.
[0148] Because of the unique features of this invention the method
of assembly is modified from the conventional syringe assembly. The
method is illustrated in FIGS. 42-49. The pre-capped plunger is
oriented with open channel 33 facing up, is placed on a peg passing
through the proximal window of the plunger while spring retainer
half 302a is placed under the plunger. Since the proximal part of
the plunger channel has a detent 75 that interlocks with the
retracted needle holder, their contact is prevented by placing a
spacer 602 between the components to prevent interlocking (FIGS.
43-44). The spacer is placed in the plunger channel and is taken
out only after the assembly, by pulling the plunger out of the
barrel. A sub-assembly consisting of the needle holder surrounded
by the compression spring and spring retainer is then placed in
plunger channel 33. Insertion of the plunger containing the
foregoing assembled components in the barrel completes the assembly
by rearranging each component because of the localized restrictions
and structural geometry of the barrel.
[0149] In FIG. 42, the switch 308 is inserted on the barrel 10 from
the nozzle 15 side past the detent 100, and rotated 160 degrees,
ready to receive and lock the Needle Holder Arm. In FIG. 43, the
rubber cap 12 is aligned and pressed on the plunger 11. Spring
retainer 302 is aligned under the plunger 11 adjacent to the distal
plunger plate. 25. In FIG. 44, the plunger with open channel 33 is
placed on a square indexing pin 600 passing through a detent window
or opening 601 in the plunger provided for this purpose. It blocks
the detent 75 and keeps plunger channel open for assembly of parts.
Also, a spacer rod 602 is placed in plunger channel adjacent to the
square indexing pin. In FIG. 45, a sub-assembly including the
needle holder and spring 300 inserted into the spring retainer 302
is placed in the plunger channel next to the spacer rod 602, and
the spring retainer parts 302a, 302b are snapped together. In FIGS.
45-46, the plunger assembly is inserted in the barrel 10 and switch
308 is rotated to lock the needle holder arm. All the components
are now properly re-arranged, aligned and assembled automatically.
In FIG. 47, the plunger 11 is pulled out to discard the spacer rod
602.
[0150] Because the needle holder 14 is retracted directly into the
plunger 11 itself, the rather than into the barrel cavity, the
plunger 11 need not be fully extended out of the barrel for needle
retraction to occur. Thus, when discarded following use, the
needle-syringe assembly contributes minimally to the bulk of
refuse. Since retraction of the needle 13 is effected by the spring
or other elastic biasing means, upon releasing the latch, the hand
of a user does not come into the vicinity of the needle point,
thereby minimizing the possibility of a needle prick during
retraction. Moreover, the assembly employs substantially the same
number of components as conventional syringes, and does not require
additional guards, sheaths, sleeves, etc. to conceal the needle
following use.
Intravenous Catheter Insertion Syringe.
[0151] Intravenous access is a lifeline of critically ill patients
as a primary avenue of administration of fluids and medicines, yet
it can be a difficult procedure. There is therefore a need to place
a catheter consisting of a non-traumatic flexible polymeric tube in
a patient's vein. Since polymeric catheters, although non-traumatic
to veins, can not penetrate the skin and vein, a hypodermic needle
has to be used first to create an initial puncture and guide the
catheter by sliding over it. This over-the-needle (OTN) catheter
placement syringe is disclosed in FIG. 48-54 and has essentially
the same components of the retractable needle syringe as shown and
described above. However, the needle holder 14 is replaced by an
integral needle 713 which also functions as needle holder 714 and
has all the functional features of the above-described needle
holder 14 including a side hole 713a located in barrel cavity close
to the nozzle. The remaining proximal part of the needle 714a is
blocked beyond the side hole 713a. It has an insert-molded head 730
to support the spring 300 as well as side arm 732 to engage to the
barrel via a switch. The "O" ring 202 is replaced by a synthetic
elastomeric gasket 702 press fit in the nozzle 15 of the syringe. A
step between the needle and needle holder is avoided to prevent
back flow of the fluids when the plunger is advanced over the
retracted needle that has a smaller diameter than the opening in
the rubber stopper.
[0152] Veins are mobile and slippery structures. They are also
tortuous. Hence a straight hypodermic needle cannot be pushed too
far because of the danger of double puncture. A soft and
non-traumatic catheter, once in vein can however be advanced for
longer length. However, it is also essential to confirm that the
fluid path is continuous, and that the catheter is in vein. A free
flow of the heparinized saline indicates that the catheter is
located in the vein and that it is open. Heparinized saline also
prevents the clotting of blood in catheter as well as the vein.
Infusion of heparinised saline as soon as venous access is obtained
to prevent clotting of the vein by blood is a good strategy and is
universally followed. Saline filled syringe to obtain venous access
is good practice, and will be clear from the method of use depicted
in FIGS. 50-54.
[0153] In FIGS. 48-54, over-the-needle ("OTN") catheter assembly
includes an OTN catheter 80 and the above-described syringe
assembly with a hypodermic needle 13 modified as noted above
mounted therein. The catheter 80 is a polymeric catheter having an
elongated tip 82. Prior to use of the OTN catheter assembly, a
proximal end female connector 84 of the OTN catheter 80 is
coaxially mounted over the nozzle 15 and the hypodermic needle 713
protrudes through both the nozzle 15 and the OTN catheter 80. Prior
to and during normal use of the OTN catheter assembly, the OTN
catheter 80 is held engaged over the nozzle 15 of the syringe
assembly by suitable means, such as locking luer tapers on the
outer surface of the nozzle 15 and the inner surface 81 of the end
84 of the catheter 80. The elongated tip 82 of the catheter 80
follows the beveled tip of hypodermic needle 713. Prior to use,
i.e., prior to inserting the needle 713 and catheter tip 82 into a
vein, the needle 713 and catheter tip 80 are enclosed by a
removable cap similar to the cap 200.
[0154] The illustrated embodiment of the catheter 80 includes an
internal valve 85 that normally closes the cavity of the female
luer end 84 of the catheter to prevent back flow of blood when
disconnected from syringe or fluid line. The valve 85 opens to
permit the entry of the nozzle end of the syringe and permits fluid
communication. It again stops the back flow of fluids when the
syringe nozzle is withdrawn from the catheter. When another fluid
line that also has a male luer end is subsequently connected to the
luer end 84, the valve 85 may be opened to permits fluid
communication.
[0155] The purpose of the locking means, such as luer tapers, is to
assure mechanical unity of the syringe with the OTN catheter so
that insertion force applied to the syringe barrel is directly
transmitted to the hypodermic needle 713 and catheter 80. Release
of the locking luer taper disassociates this mechanical unity,
permitting the syringe (with the retracted needle 713) to be
removed from the catheter 80.
[0156] To use the OTN catheter-syringe assembly, as shown in FIGS.
50-54, the skin of a patient is first prepared and a peripheral
vein 800 is made prominent and cleaned with antiseptics.
[0157] Under aseptic precautions, the OTN syringe cap 200 is
removed and syringe is partially filled with heparinised saline.
The vein is punctured with the needle 713 projecting at the
catheter tip 82 (FIG. 51), and the location of the needle tip is
judged by the change in color under the catheter or by the
appearance of blood in the catheter and/or the flashback or
aspiration of blood in the syringe.
[0158] Once the location of the needle tip in the vein is
confirmed, by aspiration of blood and injection of saline in the
vein, the needle holder is retracted by release of the switch as
described above (FIG. 52). At this stage the plastic catheter can
be advanced in the vein without fear of trauma since the sharp
needle is already retracted, in the manner described above.
[0159] Continuity of catheter and its location and, confirmation
that the needle 713 and catheter tip 82 are located in the vein can
be made by viewing blood entering the catheter 80 by capillary
action. It, however, is also possible to confirm a flashback within
the syringe barrel by partially retracting the plunger 11 relative
to the barrel 10 to assure that continuity between the barrel
nozzle 15 and the vein is still established. In this regard, the
side aperture of the needle holder 714 opens into the syringe.
Confirmation of proper insertion in the vein therefore is indicated
by blood entering the barrel chamber via the side aperture in the
needle holder 714.
[0160] When fluid path is continuous, the entire heparinised saline
in the syringe is infused in the vein to fill the vein with
anticoagulants to prevent clotting.
[0161] While securing and retaining the OTN catheter 82 in the
vein, and blocking the female end of OTN by the valve 85 the
syringe assembly is removed (FIG. 54) and an intravenous line is
connected to the catheter 80, as conventional. Finally, the
catheter 80 is secured to the skin of the patient by adhesive tape.
The syringe with the retracted and lo locked needle is then
disposed of as biological waste. In order to prevent leakage of the
fluid the syringe may be capped.
[0162] Without the improvements recited herein it was not possible
to ascertain with certainty [1] the catheter is in fact in vein
after the puncturing needle is withdrawn [2] that there is no false
passage [3] that the vein is filled with anti-coagulant saline and
that it is open--not clotted.
[0163] The various novel and improved syringe assemblies as
described above offer a number of advantageous features, including
but not limited to various combinations of the following:
[0164] The plunger channel 33 adds precision to the needle holder
movement. For example, straight axial retraction of the needle in
the plunger channel 33 avoids angulation of the needle and puncture
of the barrel cavity. It does not require extending the overall
length of the syringe as a result of the plunger being pulled out,
and avoids the need for special measures such as breaking the
plunger to prevent re-use. The linear movements of the plunger in
the barrel are mechanically indexed to actuate retraction of the
needle after the medicine is injected in the patient.
[0165] The number of the components in the present invention is not
significantly different from a conventional syringe to keep it cost
effective.
[0166] Use of the sliding needle holder eliminates the usual female
needle holder on the barrel nozzle, which eliminates the associated
dead-space and quantity of wasted medications left over in the
syringe nozzle and the conventional needle holder.
[0167] The operation of the syringe is one-way so that accidental
misuse is minimized, i.e, once retracted the needle holder is
locked in place, so the needle cannot be re-extended.
[0168] Operation of the syringe is particularly safe because all
the required manipulations of the various parts of the syringe are
performed at or near the proximal end of the syringe, well away of
the needle, during both the normal and retracting modes of
operation.
[0169] In the rare event when only a partial dose of medicine is
given to the patient, the syringe with leftover medicine can be
rendered safe by retraction of the needle holder, while capping of
the nozzle will prevent spillage.
[0170] It should be noted that the syringe assembly as described
may be used to dispense medication or as a blood collection device.
It may also be used to place an over-the-needle catheter, as
described above.
[0171] With a few innovative modifications, present invention can
be converted into a pre-filled retractable needle, single use
safety syringe. These syringes are used in the pharmaceutical
industry. Instead of packaging the injectable medications in vials
or ampoules the sterile medications are filled in the syringe
itself. It saves the entire packaging cost of ampoules and vials,
as well as cost of professionals, who transfer the medication from
the vials to the syringes in sterile atmosphere, before it is
injected in the patients. With a pre-filled syringe, it is just
inject the medicine and dispose of the syringe. One of the major
problems involved in the pre-filled syringe technology is the
compatibility of the syringe components with the medications stored
in syringe for long shelf life. Newer plastics that can be used in
this invention are sufficiently neutral, nonreactive and address
that problem. A second consideration is that the medicine filled in
a syringe should not leak, either from nozzle end or from rubber
piston end. Further, the sterility of medicine must be preserved,
and an accidental discharge of medicine must be avoided, until use.
In addition, the syringe used to inject the medicine in patient
must comply with the "needle stick" prevention regulations
mentioned above.
[0172] Prevention of fluid leak is an important function of the
syringe. The problem is that of maintaining a seal at either end
over a long period of time. The nozzle of the present syringe
invention can be provided with male (external) luer taper to
install a tight fitting cap 200 with female (internal) luer taper
for protection of needle point, as well as preventing accidental
needle stick, because the hypodermic needle emerges from within the
nozzle. The luer taper lock requires an intentional compound
roto-linear movement to disengage. It therefore resists vibratory
as well as other forces ordinarily tending to separate the
components.
[0173] A luer lock when re-enforced with a screw thread molded on
contacting surfaces of the nozzle 15 as well as inside cap 200, is
further assurance that cap would not separate once installed to
maintain the seal. The protective cap 200, intended for the
pre-filled syringe, is in addition partially filled with a
nontoxic, tissue-compatible, inert, elastic non coring, material
such as silicone to an appropriate length sufficient to enclose the
tip portion part of the hypodermic needle of the retractable needle
syringe. When such a needle protector is installed on the nozzle of
the retractable needle syringe, it assures a perfect seal both to
prevent the leak of air as well as any fluid contained within the
prefilled barrel despite a modest in-advertent push on the
plunger.
[0174] The rubber piston 12, installed on the plunger head 21,
seals the needle holder in its center and seals with the barrel
along its periphery. When the syringe is pre-filled with medicine,
the rubber piston is supported by the spring retainer 302. Further,
the needle holder anchors it to the barrel of the syringe.
Accordingly, the plunger and the rubber cap cannot be pulled out
beyond this pre-filled location, unless this locking mechanism is
intentionally and voluntarily disabled, so there is no chance of a
leak from the proximal end.
[0175] The effective sealing at the nozzle as well as the
above-mentioned mechanical anchoring of the rubber piston is not
likely to permit movement of the plunger to effect a fluid leak.
However, another barrel-plunger lock mechanism consisting of a clip
that anchors to the barrel and a 90 degrees angled plate that
engages with the linear slots on the proximal part of the plunger
flange 64 immobilizes the plunger in relation to the barrel. This
prevents any inadvertant pull or push to be transmitted to the
medicine chamber and assures additional security against
advancement of plunger within the barrel.
[0176] Since prefilled medicine obligates that the plunger be
pulled out, and since the pulled out plunger is unprotected because
it is out of the barrel, this assembly is further fortified.
Referring to FIGS. 73-77, the plunger portion 111 projecting out of
barrel 10 is split in two halves 111a, 111b. Each half is provided
with a hinge 113a, 113b that permits each half to be folded by the
side of the barrel (see FIG. 77). The hinge mechanism is such that
in normal use the hinge gets pushed within the barrel and can not
come out nor can it be unfolded unless pulled out of the barrel.
This mechanical arrangement offers ultimate security to the
operation of the prefilled syringe.
[0177] The mechanical structures of the present invention described
herein assure that the retraction mechanism cannot be disabled by
the hydraulic pressure generated inside the barrel. Operation of a
pre-filled syringe is simple in that everyone removes the
protective cap before injection, and plunger lock invariably
reminds one to rotate the locking ring to initiate the injection of
medicine under aseptic precautions.
[0178] FIGS. 55-64 and FIGS. 65-71 illustrate two further
embodiments of a retractable needle, single use safety syringe in
accordance with the invention. These two additional embodiments
differ from the embodiments heretofore described, in that the latch
or switch arrangement is entirely internal to the barrel 10 of the
syringe. The barrel therefore has no need for and therefore omits
the slot or guide track 19 shown in the previous figures of
drawing. In this regard, the barrel for use with the embodiment of
FIGS. 55-64 is generally cylindrical and circular in cross-section
without any breaks in the outer wall, as indicated generally by
FIG. 63, while the barrel for use with the embodiment of FIGS.
65-70 is of the type shown in FIG. 68, with an enlarged wall
portion 29 along one side thereof, similar to the barrel shown in
FIGS. 8 and 9 described above, however, without the detent elements
100, such that the external surface is relatively smooth, having
one enlarged diameter segment at the extended or radially outwardly
extending wall portion 29.
[0179] Referring initially to FIGS. 55-58, an alternate embodiment
of a two-piece spring retainer element 1302a, 1302b is illustrated.
The elements 1302a and 1302b become one structure when snapped
together. They can also be molded as a single piece with an
identical function. The spring retainer element 1302a is similar to
the spring retainer shown in FIGS. 20 and 21, in that it includes a
generally semi-cylindrical body portion 812 having connector
members 814 which mate with similar or complementary connectors on
the second spring retainer element 1302b. The spring retainer
element 1302a also includes an extension 1303 which terminates in a
spring support or retaining element 1310 with a through opening for
receiving the needle holder axially movable therethrough. An
oppositely projecting extension 1312 functions to engage the needle
holder within the plunger channel in fixed position in normal
operative state. It retracts the needle holder at the point of
plunger advance when the ramps deflect the plate radially. This
structure eliminates the requirement of a switch for causing
retraction and can be used with a conventional barrel.
[0180] In this regard, the extension 1312 terminates in a gripping
lip or flange 804 which has a right angle 805 (that is, at right
angles to the extension plate 1312) for overlying a complementary
flat surface portion 1037 at a top surface of a needle holder
element 1014 shown in FIGS. 60-62, and further described below. The
retaining lip 804 also has a leading beveled surface 806 to
facilitate initial passage of the enlarged head 1035 of the needle
holder 1014 thereby for engagement with the flat top portion 1037
of the top surface of the enlarged head 1035 of the needle holder
1014 (see FIGS. 60-62).
[0181] The extension 1303 has a semi-cylindrical channel 810 for
receiving and holding in place the compression spring 300 described
above.
[0182] The proximal extension plate or wall 1312 has opposing side
surfaces 802 located and sized so as to span over the walls 60, 62
of the channel 33 of the plunger 11. An upper edge surface of the
plate 1312 to either side of the retaining lip 806 has a generally
V-shaped, ramped groove 808 which is of complementary form for
gaging the upper ramped and V-shaped surfaces of the projections 70
and 72 of the plunger 11.
[0183] Referring briefly to FIGS. 58 and 59, the second segment or
portion of the spring retainers indicated by reference numeral
1302b and has a semi-cylindrical portion 820 which has mating
projections 815 for engaging with the apertures 814 in the portion
1302a shown in FIG. 55 to assemble the two portions of the spring
retainer together. In other respects, the spring retainer 1302b is
substantially identical to the spring retainer element or portion
302b. However, the spring retainer portion 1302b has an additional
axially extending reduced thickness portion 830 which has an
elongated window 832 for interfitting with a detent 842 formed in a
bottom rib 64a of a modified plunger 11b (see FIG. 72) which
includes a ramp 840 which leads into a recess 842, such that the
ramp 840 will pass into and engage the window 832 upon the
over-extension or over-advancement of the plunger for retraction of
the needle as described above. The reduction in the thickness of
extension plate 830 offers a spring-like action for positive
engagement of the detent 842 on the rib 64 of the plunger.
[0184] Referring briefly to FIG. 64, the elements of FIGS. 55-63
are shown in assembled condition. Upon the above-described
over-advancement of the plunger 11, the projections 70 and 72
engage the grooved edges 808 of the extension 1312, resiliently
bending back the top portion of the plate so as to release
engagement of the retaining lip 806 from the flat area 1037 on the
top 1035 of the needle holder 1014, thereby allowing the spring 300
to expand and retract the needle holder and needle. As also shown
in FIG. 64, when this occurs, the detent comprising the ramp 840
and recess 842 engages the window 832 to hold the assembly in a
locked condition so as to render it completely locked and
nonreusable and prevent retraction of the plunger, as well.
[0185] Referring next to FIGS. 65-70, another embodiment of a
spring retainer 2302a, needle holder 2014 and barrel 10 for
achieving for "instant" retraction entirely internally of the
barrel, is shown. This embodiment, as also shown in the assembled
view of FIG. 71, operates for releasing the needle holder to
retract the needle and locking the components, including the
plunger, in place in similar fashion to the embodiment of FIGS.
55-64 described above. That is, all of the mechanisms are carried
internally of the barrel whereby no channel, slot, track or other
opening in the barrel is needed or provided. In order to
accommodate the mechanism of this embodiment, however, the barrel
has a radially narrow increased diameter portion 29 as shown in
FIG. 68, and mentioned above.
[0186] Referring initially to FIGS. 65-67, the spring retainer
portion 2302a interfits with the spring retainer portion 1302b as
shown in FIGS. 58 and 59. In this regard, the window 832 in the
spring retainer element 1302b interlocks in the same fashion as
described above with respect to the detent portion 840, 842 of the
plunger 11b of FIG. 72, as also illustrated in FIG. 71. In this
regard, the spring retainer portion 2302a includes a
semi-cylindrical portion 812 which interfits snugly within the
interior wall of the barrel 10 and is retained in place by a raised
ring 120 as mentioned hereinabove. An extension 2303 and spring
supporting portion 2310 with through aperture for receiving the
needle holder are the same as in the above described embodiments.
Also, as in the above described embodiments, a small slot or groove
2304 interfits with a mating projection within the barrel to
properly index or position the spring holder and prevent rotation
thereof with respect to the barrel 10.
[0187] In the embodiment of FIGS. 65 and 66, a proximal flexible
extension plate 902 similar to the plate 802 is provided and also
is of a width to span and slidably engage the two walls or ribs 60,
62 which form the channel 33 in the plunger 11. In this regard, the
plunger 11b of FIG. 72 is utilized in connection with this spring
retainer. In the same fashion as the embodiment of FIG. 55, the
spring retainer 2302a has at an end of the plate or projection 902
a pair of shaped recesses or grooves 908 which are of complementary
shape for engaging the upper edge portions of the spring release
projections 70 and 72 of the plunger 11b.
[0188] Finally, in order to releasably retain the needle holder, a
through opening or window 905 is defined between flexible plate 902
and a support plate 903. The flexible plate 902 has an arch 902a
and is rendered flexible by two slots s1 and s2. The slots separate
the plate 902 and offer flexibility so that it can flex radially
outwardly in response to a mechanical push of the projections 70
and 72 located on the plunger. With the deflexion of the arch 902a,
the needle holder locked underneath is released. The support plate
903 is fixed to the spring retainer 2302a and extends proximally to
form a concave margin to accomodate the needle holder which is
locked under the plate 902.
[0189] As best viewed in FIG. 71, the opening 905 releasably
engages a radially projecting, relatively short arm 2032 of the
needle holder 2014 shown in FIGS. 69 and 70. This needle holder is
substantially similar in all other respects to the needle holders
14 and 1014, having a recess or slot 2041 formed by an elongate
L-shaped extension 2039. This extension 2039 mounts the lateral arm
2032 at its distal end. The slot or opening 2041 receives and
guides one end of the compression spring 300. The slot 2031
performs the same function as the slot 31 of the needle holder 11
described above, and the parts 2026, 2030, 2036 are also
substantially the same as the parts 26, 30 and 36 of the needle
holder described hereinabove. The top surface of the enlarged head
2035 of the needle holder 2014 does not require, and is therefore
shown without, the flat surface portion 1017 of the embodiment of
FIGS. 50, 60-62. It will be noted that the enlarged portion 29 of
the barrel is aligned, upon assembly and during operation, with the
lateral arm 32 of the needle holder, and with the plate 902 of the
spring retainer to provide a relief space for the plate to flex
back sufficiently to release the radially extending arm 2032 upon
overadvancement of the plunger in the manner described hereinabove
for release of the needle holder assembly. This results in
retraction of the needle and locking of the parts in a retracted
and nonreusable condition, including locking the plunger in an
advanced position, as described above.
[0190] While particular embodiments and applications of the present
invention have been illustrated and described, it is to be
understood that the invention is not limited to the precise
construction and compositions disclosed herein and that various
modifications, changes, and variations may be apparent from the
foregoing descriptions without departing from the spirit and scope
of the invention as defined in the appended claims.
* * * * *