U.S. patent application number 12/862315 was filed with the patent office on 2010-12-16 for syringe and removable needle assembly having binary attachment features.
This patent application is currently assigned to Becton, Dikinson and Company. Invention is credited to Christina J. D'Arrigo, Anthony Economou, Eric Schiller.
Application Number | 20100318038 12/862315 |
Document ID | / |
Family ID | 38819381 |
Filed Date | 2010-12-16 |
United States Patent
Application |
20100318038 |
Kind Code |
A1 |
D'Arrigo; Christina J. ; et
al. |
December 16, 2010 |
Syringe and Removable Needle Assembly Having Binary Attachment
Features
Abstract
A syringe and detachable needle assembly having binary
attachment features include an elongate syringe barrel having a
longitudinal axis, an open proximal end and an open distal end
including a collar. The collar includes the cylindrically shaped
sidewall having an inside surface and an outside surface. A needle
assembly includes the hub having a body portion including a
proximal end, a distal end and a conduit therethrough. A cannula
having a distal end, a proximal end and a lumen therethrough is
attached to the distal end of the hub so that the lumen is in fluid
communication with the chamber. A lug is provided on one of the
collar and the hub and a ramp and a rest surface is provided on the
other of the collar and the hub. The ramp is oriented at an acute
angle with respect to longitudinal axis for guiding the lug during
needle assembly attachment, to the rest surface forcing the hub to
contact the barrel to form a seal the hub and the barrel.
Inventors: |
D'Arrigo; Christina J.;
(Hoboken, NJ) ; Schiller; Eric; (Kinnelon, NJ)
; Economou; Anthony; (Sparta, NJ) |
Correspondence
Address: |
David W. Highet, VP & Chief IP Counsel;Becton, Dickinson and Company
(Diehl Servilla, LLC), 1 Becton Drive, MC 110
Franklin Lakes
NJ
07417-1880
US
|
Assignee: |
Becton, Dikinson and
Company
Franklin Lakes
NJ
|
Family ID: |
38819381 |
Appl. No.: |
12/862315 |
Filed: |
August 24, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11462154 |
Aug 3, 2006 |
|
|
|
12862315 |
|
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Current U.S.
Class: |
604/240 |
Current CPC
Class: |
B29C 45/44 20130101;
A61M 5/3202 20130101; A61M 2005/31516 20130101; B29L 2031/7544
20130101; B29C 45/33 20130101; A61M 5/347 20130101 |
Class at
Publication: |
604/240 |
International
Class: |
A61M 5/34 20060101
A61M005/34 |
Claims
1. A syringe and detachable needle assembly having binary
attachment features comprising: an elongate syringe barrel having a
longitudinal axis, an inside surface defining a chamber for
retaining fluid, an open proximal end, an open distal end including
a collar, a portion of said collar including a cylindrically shaped
sidewall having an inside surface and an outside surface; a needle
assembly including a hub having a body portion including a proximal
end, a distal end, a conduit therethrough, said needle assembly
further including a cannula having a distal end, a proximal end and
a lumen therethrough, said proximal end of said cannula being
connected to said distal end of said hub so that said lumen is in
fluid communication with said chamber; a lug on said collar, and a
ramp and a rest surface on said hub, said ramp oriented at an acute
angle with respect to said longitudinal axis for guiding said lug,
during needle assembly attachment, to said rest surface; and a
discontinuity between said ramp and said rest surface which
interrupts a path of said lug as it travels up said ramp to said
rest surface, thereby increasing an amount of torque necessary to
transition said lug from said ramp to said rest surface and forcing
said hub to contact said barrel to form a seal between said hub and
said barrel.
2. The syringe assembly of claim 1 further including a distally
facing annular surface projecting inwardly into said open proximal
end of said barrel and a proximally facing annular surface on said
body portion of said hub contacting said distally facing annular
surface to form a seal between said hub and said barrel.
3. The syringe assembly of claim 2 wherein said proximally facing
annular surface on said body portion of said hub is a flexible
skirt.
4. The syringe assembly of claim 1 wherein said hub is loosely
retained by said barrel during most of the travel of said lug along
said ramp so that said syringe and said needle assembly are
incapable of injecting fluids without leaking fluid outside said
lumen while said hub is loosely retained.
5. The syringe assembly of claim 1 wherein said discontinuity
increases the length of said ramp so that said lug moves slightly
farther proximally with respect to said collar before falling back
onto said rest surface.
6. The syringe assembly of claim 1 further including a projection
on said hub configured for contacting a protuberance on said collar
for providing additional tactile feedback to the user during
rotation of said needle assembly with respect to said barrel as
said lug transitions from said ramp to said rest surface.
7. The syringe assembly of claim 1 wherein said lug includes four
lugs and said ramp includes two ramps and said rest surface
includes two rest surfaces.
8. The syringe assembly of claim 1 wherein said rotation of said
hub with respect to said barrel is less than 100.degree. while said
lug travels along said ramp during installation of said needle
assembly to said barrel.
9. The syringe assembly of claim 1 wherein said lug projects
outwardly from said body portion of said hub and said ramp is on
said inside surface of said sidewall.
10. The syringe assembly of claim 9 wherein said rest surface
includes a portion of the periphery of an aperture through said
sidewall.
11. The syringe assembly of claim 1 further including an outwardly
projecting annular sealing ring on said body portion of said hub
for sealingly engaging said sidewall of said collar to form a
secondary seal between said hub and said barrel.
12. The syringe assembly of claim 11 wherein said annular sealing
ring is an elastomeric o-ring.
13. The syringe assembly of claim 11 wherein said annular sealing
ring is a tapered projection having a base adjacent to said body
portion and a free end, said tapered projection being wider at said
base than at said free end.
14. The syringe assembly of claim 11 wherein said annular sealing
ring is integrally formed with said body portion.
15. The syringe assembly of claim 1 further including an elongate
plunger rod having a proximal end, a distal end and a stopper at
said distal end of said plunger rod, said stopper being slidably
positioned in fluid tight engagement with said inside surface of
said barrel for displacing fluid from said chamber through said
cannula by relative motion of said plunger rod with respect to said
barrel.
16. The syringe assembly of claim 15 wherein said stopper includes
a distally facing projection for partially occluding said conduit
in said hub when said stopper is in its distal most position inside
said barrel.
17. The syringe assembly of claim 1 further including an elongate
hollow needle shield having a distal end and an open proximal end
removably engaged to said hub so that said needle shield covers
said cannula.
18. The syringe assembly of claim 1 wherein said hub and said
cannula are integrally formed of thermoplastic material.
19. The syringe assembly of claim 1 wherein said cannula includes a
blunt distal tip.
20. A syringe and detachable needle assembly having binary
attachment features comprising: a elongate syringe barrel having a
longitudinal axis, and inside surface defining a chamber for
retaining fluid, an open proximal end, an open distal end including
a collar and a distally facing annular surface projecting inwardly
into said open proximal end, a portion of said collar including a
cylindrically shaped sidewall having an inside surface and an
outside surface; a needle assembly including a hub having a body
portion including a proximal end, a distal end, a conduit
therethrough, a proximally facing annular surface on said body
portion contacting said annular surface of said barrel forming a
seal between said hub and said barrel, said needle assembly further
including a cannula having a distal end, a proximal end and a lumen
therethrough, said proximal end of said cannula being connected to
said distal end of said hub so that said lumen is in fluid
communication with said chamber; two lugs projecting outwardly from
said body portion of said hub and two ramps on said inside surface
of said collar having a rest surface at a proximal end of each
ramp, said ramps oriented at an acute angle with respect to said
longitudinal axis for guiding said lugs, during attachment of said
needle assembly to said barrel, to said rest surfaces forcing said
annular surface on said hub to contact said annular surface on said
barrel to form said seal between said hub and said barrel, said
rotation of said hub with respect to said barrel being less than
100.degree. while said lug travels along said ramp during
installation of said needle assembly, during said travel said hub
being loosely retained by said barrel; a discontinuity between said
ramps and said rest surfaces which interrupts a path of said lugs
as they travel up said ramps to said rest surfaces, thereby
increasing an amount of torque necessary to transition said lug
from said ramps to said rest surfaces and forcing said hub to
contact said barrel to form a seal between said hub and said
barrel; and an elongate plunger rod having a proximal end, a distal
end and a stopper at said distal end of said plunger rod, said
stopper being slidably positioned in fluid tight engagement with
said inside surface of said barrel for displacing fluid from said
chamber through said cannula by relative motion of said plunger rod
with respect to said barrel.
21. The syringe assembly of claim 20 wherein said two lugs include
four lugs and said inside surface of said collar includes a guide
surface running along and spaced from each ramp for guiding said
lugs during removal of said needle assembly from said barrel.
22. The syringe assembly of claim 20 further including an outwardly
projecting annular sealing ring on said body portion of said hub
for sealingly engaging said sidewall of said collar to form a
secondary seal between said hub and said barrel.
23. A syringe and detachable hub having binary attachment features
comprising: an elongate syringe barrel having a longitudinal axis,
an inside surface defining a chamber for retaining fluid, an open
proximal end, an open distal end including a collar, a portion of
said collar including a cylindrically shaped sidewall having an
inside surface and an outside surface; a hub having a body portion
including a proximal end and a distal end; a lug on said hub, and a
ramp and a rest surface on said collar, said ramp oriented at an
acute angle with respect to said longitudinal axis for guiding said
lug, during hub attachment, to said rest surface forcing said hub
to contact said barrel to form a seal between said hub and said
barrel, said rotation of said hub with respect to said barrel being
less than 180.degree. while said lug travels along said ramp during
installation of said hub to said barrel; and a discontinuity
between said ramp and said rest surface which interrupts a path of
said lug as it travels up said ramp to said rest surface, thereby
increasing an amount of torque necessary to transition said lug
from said ramp to said rest surface and forcing said hub to contact
said barrel to form a seal between said hub and said barrel.
24. The syringe assembly of claim 23 further including said hub
having a conduit therethrough; and a cannula having a distal end, a
proximal end and a lumen therethrough, said proximal end of said
cannula being connected to said distal end of said hub so that said
lumen is in fluid communication with said chamber.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation application of application Ser. No.
11/462,154, filed Aug. 3, 2006, which is incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates to syringes with removable
needle assemblies. More particularly, the present invention relates
to syringes having binary attachment features, and a method of
making a syringe barrel for the present invention.
BACKGROUND
[0003] Syringe assemblies designed for use with replaceable needle
assemblies usually contain a luer slip or locking luer type fitting
for securing the needle assembly to the syringe barrel. These
connections rely on an elongate frusto-conically shaped syringe
barrel tip which frictionally engages a frusto-conically shaped
passageway in a needle hub. The relatively acute angle of the
syringe tip, measured from the longitudinal axis of the syringe
barrel, provides an excellent seal between the syringe tip and the
hub. However, slight variations in the angle or diameter of the
tapered surfaces of the syringe barrel and/or the needle hub
produce large variations in the relative position of the needle hub
with respect to the end of the barrel and, therefore, variations in
dead space. The space inside the barrel tip and between the end of
the barrel tip and the end of the cavity in the hub constitutes a
dead space containing liquid that cannot be delivered by the
syringe.
[0004] In the case of expensive medications and multi-patient
immunization programs, medication lost in the dead space can become
costly. This is especially true in immunization programs involving
thousands of people. Controlling dead space to a minimum may result
in more people being immunized with the same amount of medication
provided for the program.
[0005] The prior art also teaches a flat seal, perpendicular to the
longitudinal axis of the syringe barrel which mates with a
complimentary flat seal on the needle hub for use with a threaded
needle assembly and barrel engagement structure.
[0006] The flat seal reduces the portion of dead space attributable
to variations and barrel and hub tolerances. However, unlike the
locking luer type fittings that become tighter as additional torque
is applied to the needle hub, syringe assemblies having flat and
low angle seals reach a sealed condition in a rather abrupt fashion
due to their geometry.
[0007] When syringes and needle assemblies of any of the
above-mentioned geometries are assembled in the manufacturing
facility, the needle assembly can be attached to the syringe barrel
using an optimal amount of torque applied to the needle hub
therefore avoiding needle hubs that are not properly attached which
can lead to leaking of medication and needle hubs which are over
tightened which can have long term consequences due to creep in the
plastic components which relax over time and lose their preload.
However, in a clinical setting the attaching of a needle assembly
to a syringe barrel is not done with the consistent controlled
force found in the manufacturing process. Some users of the syringe
and needle assembly are strong, some are weak and many have their
own preconceived opinion regarding what the proper torque needed to
attach a needle assembly.
[0008] Although the prior art teaches many syringe barrel and
needle hub connecting structures, there is still a need for a low
dead space syringe which will not attach the needle assembly to the
syringe barrel unless an adequate amount of torque is applied to
the needle hub and which will not tighten further after proper
installation has occurred.
SUMMARY OF THE INVENTION
[0009] A syringe and detachable needle assembly having binary
attachment features includes an elongate syringe barrel having a
longitudinal axis, an inside surface defining the chamber for
retaining fluid, an open proximal end and an open distal end
including a collar. A portion of the collar includes a
cylindrically shaped sidewall having an inside surface and an
outside surface. A needle assembly includes a hub having a body
portion including a proximal end, a distal end and a conduit
therethrough. The needle assembly further includes a cannula having
a distal end, a proximal end and a lumen therethrough. The proximal
end of the cannula is connected to the distal end of the hub so
that the lumen is in fluid communication with the chamber in the
barrel. A lug on one of said collar and said hub, and a ramp and a
rest surface on the other of said collar and said hub. The ramp is
oriented at an acute angle with respect to the longitudinal axis
for guiding the lug during needle assembly attachment, to the rest
surface forcing the hub to contact the barrel to form a seal
between the hub and the barrel. Rotation of the hub with respect to
the barrel is less than 180.degree. when the lug travels along the
ramp during installation of needle assembly to the barrel.
[0010] The syringe assembly may further include a distally facing
annular surface projecting inwardly from the open proximal end of
the barrel and a proximally facing annular surface on the body
portion of the hub contacting the distally facing annular surface
to form a seal between the hub and the barrel.
[0011] The proximally facing annular surface on the hub may be in
the form of a flexible annular skirt.
[0012] The hub is preferably loosely retained by the barrel during
most of the travel of the lug along the ramp so that during this
time the hub is not sealed to the barrel and an attempt to remove
the needle shield in an axial direction will cause the hub to
become disconnected from the barrel.
[0013] The syringe assembly may include a discontinuity between the
ramp and the rest surface for providing additional tactile feedback
to the user during rotation of the needle assembly with respect to
the barrel as the lug transitions from the ramp to the rest
surface. The discontinuity may provide additional resistance to the
movement of the lug as it transitions from the ramp to the rest
surface. The discontinuity may also increase the length of the ramp
so that the lug moves slightly farther proximally with respect to
the collar before falling back onto the rest surface.
[0014] The syringe assembly may include a projection on the hub
configured for contacting a protuberance on the collar for
providing additional tactile feedback to the user during rotation
of the needle assembly with respect to the barrel as said lug
transitions from said ramp to said rest surface.
[0015] The syringe assembly of the present invention is preferably
configured so that the hub is loosely retained by the barrel during
most of the travel of the lug along the ramp so that an attempt to
remove the needle shield in an axial direction results in the hub
becoming disconnected from the barrel.
[0016] The syringe assembly may include four lugs and the ramp may
include two ramps with two rest surfaces. It is also desirable to
have rest surfaces without ramps, e.g., two opposed ramps with rest
surfaces and two opposed rest surfaces without ramps.
[0017] The syringe assembly is preferably configured so that the
rotation of the hub with respect to the barrel is less than
100.degree. while the lug travels along the ramp during
installation of the needle assembly to the barrel.
[0018] The body portion of the hub may also include an outwardly
projecting annular sealing ring for sealing engaging the sidewall
of the collar to form a seal between the hub and barrel. The
sealing ring may take the form of an elastomeric o-ring. The
annular sealing ring may be integrally formed with the body portion
of the hub. Further, the annular sealing ring may be configured to
be a tapered projection having a base adjacent to the body portion
of the hub and a free-end wherein the tapered projection is wider
at its base than at its free-end.
[0019] The syringe assembly may further include an elongate plunger
rod having a proximal end, a distal end and a stopper at the distal
end slidably positioned in fluid tight engagement with the inside
surface of the barrel for displacing fluid from the chamber through
the cannula by relative motion of the plunger rod with respect to
the barrel. The stopper may also include a distally facing
projection for the partially occluding the conduit in the needle
hub when the stopper is in its distal most position inside the
barrel.
[0020] The needle assembly may also include an elongate hollowed
needle shield having a distal end and an open proximal end
removably engaging the hub so that the needle covers the
cannula.
[0021] The cannula may be integrally formed with the hub using
thermoplastic material. Further the cannula may have a sharp or a
blunt tip.
[0022] The syringe assembly of the present invention may be
configured so that a lug projects outwardly from the body portion
of the hub and a ramp is in the inside surface of the sidewall of
the barrel collar.
[0023] The syringe assembly may be configured so that a lug
projects inwardly from the body portion of the hub and a ramp is
formed on the outside surface of the sidewall of the collar of the
barrel.
[0024] The syringe assembly may be configured so that the lug
projects inwardly from the inside surface of the sidewall of the
collar and the ramp is formed on the exterior of the body portion
of the hub.
[0025] The syringe assembly may be configured so that a lug
projects outwardly from the outside surface of the sidewall of the
collar of the barrel and a ramp is formed on the inside of the body
portion of the hub.
[0026] A rest surface may include a portion of the periphery of an
aperture through the sidewall of the barrel collar.
[0027] Another embodiment of the present invention includes a
syringe and detachable hub having binary attachment features
including an elongate syringe barrel having a longitudinal axis, an
inside surface defining a chamber for retaining fluid, an open
proximal end, an open distal end including a collar, and a portion
of the collar including a cylindrically shaped sidewall having an
inside surface and an outside surface. A hub has a body portion
including a proximal end and a distal end. A lug on one of the
collar or the hub, and a ramp and a rest surface on the other of
the collar or the hub are provided. The ramp is oriented at an
acute angle with respect to the longitudinal axis for guiding the
lug, during hub attachment, to the rest surface forcing the hub to
contact the barrel to form a seal between the seal between the hub
and the barrel. The rotation of the hub with respect to the barrel
is desirably less than 180.degree. and preferably less than
100.degree. while the lug travels along the ramp during
installation of the hub to the barrel. It is not necessary that the
hub have a conduit therethrough in fluid communication with the
chamber in the barrel. The hub without a conduit therethrough or
with an occluded conduit can function as a cap to seal medication
in the syringe assembly of the present invention before the time of
use. Also, the syringe of the present invention can be used with
the needle assembly for filling the syringe with medication using
an appropriately sized cannula. After filling, the cannula is
discarded and a hub, without a conduit, is attached to the distal
end of the barrel to seal in and protect the medication. At the
time of use, the hub is removed and a needle assembly having a
cannula, appropriately sized for injection, is attached to the
barrel.
[0028] The present invention also includes a method of making an
elongate syringe barrel for use with a needle assembly having a hub
wherein the hub includes a body portion having an outwardly
projecting lug and a proximally facing annular surface. The barrel
includes a longitudinal axis, an outside surface and an inside
surface defining a chamber for retaining fluid, an open proximal
end, an open distal end including a collar and a distally facing
annular surface projecting into the open proximal end. A portion of
the collar includes a cylindrically shaped sidewall having an
inside surface and an outside surface. A ramp and a rest surface
project inwardly from the inside surface of the collar. The ramp is
oriented at an acute angle with respect to the longitudinal axis
for guiding the lug, during needle attachment, to the rest surface
forcing the annular surface on the hub to contact the annular
surface in the open proximal end of the barrel to form a seal
between the hub and the barrel. The rotation of the hub with
respect to the barrel is desirably less than 180.degree. and
preferably less than 100.degree. while the lug travels along the
ramp during installation of needle assembly to the barrel. The
method of molding comprises the steps of: providing an injection
mold having a cavity defining a syringe barrel. The mold includes a
fixed portion defining the outside surface of the barrel, a
proximal core pin defining the chamber in the barrel, a split
cavity defining the outside surface of the collar and including a
raised projection for forming an aperture in the collar, the ramp
and the rest surface, and a straight-pulled distal core pin
defining the remaining portions of the interior of the collar. The
distal core pin contacts the raised surface on the split cavity
when the mold is closed. The method further includes injecting
molten thermoplastic material into the cavity of the mold; allowing
enough time for the thermoplastic material to solidify enough to
allow movement of the barrel with respect to the mold; opening the
split cavity so that the raised projection is outside of the
collar; and removing the proximal core pin and the barrel axially
from the fixed portion of the mold without rotation of the distal
core pin.
[0029] The method of the present invention further including the
raised projection on the split cavity being further configured to
cooperate with the distal core pin to form a guide surface running
along and spaced from the ramp, for guiding the lug during removal
of the needle assembly from the barrel.
[0030] A method of the present invention may further include the
split cavity having a second projection and the core pin is
configured to cooperate with the second projection of the split
cavity to form an additional aperture in the collar and an
additional rest surface. Distal core pin is configured for defining
the remaining portions of the additional rest surface. The
additional rest surface does not have a ramp for guiding a lug
connected to it.
[0031] The method is preferably carried out with thermoplastic
materials selected from the group consisting of polypropylene,
polyethylene, polycarbonate, PET and combinations thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is an exploded perspective view of a prior art needle
assembly and syringe.
[0033] FIG. 2 is an enlarged cross-sectional view of the distal end
of the syringe barrel of FIG. 1.
[0034] FIG. 3 is a partial cross-sectional view showing a needle
assembly of FIG. 1 attached to the syringe barrel of FIG. 1.
[0035] FIG. 4 is a perspective view of a syringe and removable
needle assembly of the present invention.
[0036] FIG. 5 is an exploded perspective view of the components of
the syringe assembly of FIG. 4.
[0037] FIG. 6 is a side-elevational view of the hub of the needle
assembly.
[0038] FIG. 7 is an enlarged cross-sectional view of the distal end
of the syringe barrel of FIG. 5.
[0039] FIG. 8 is an enlarged cross-sectional view of the distal end
of an alternative syringe barrel structure.
[0040] FIG. 9 is a side-elevational view of alternative needle
assembly of the present invention.
[0041] FIG. 10 is a cross-sectional view of the distal end of a
syringe barrel for use with the needle assembly of FIG. 9.
[0042] FIG. 11 is a side-elevational view of another alternative
needle assembly of the present invention.
[0043] FIG. 12 is a cross-sectional view of the needle assembly of
FIG. 11 attached to a syringe barrel.
[0044] FIG. 13 is still another alternative needle assembly similar
to the needle assembly of FIG. 11.
[0045] FIG. 14 is perspective view of the distal end of an
alternative syringe barrel of the present invention.
[0046] FIG. 15 is a perspective view of a needle hub for use with
the syringe barrel of FIG. 14.
[0047] FIG. 16 is still another alternative needle assembly of the
present invention.
[0048] FIG. 17 is a cross-sectional view of the distal end of the
syringe barrel for use with the needle assembly of FIG. 16.
[0049] FIG. 18 is still another alternative embodiment of the
needle assembly and syringe of the present invention.
[0050] FIG. 19 is a side-elevational view of the syringe barrel of
FIG. 18.
[0051] FIG. 20 is a cross-sectional view of the prior art syringe
barrel.
[0052] FIG. 21 is a side elevation view of a threaded core used to
mold the syringe barrel of FIG. 20.
[0053] FIG. 22 is a cross-sectional view of an injection mold used
to practice the method of the present invention.
[0054] FIG. 23 is an exploded view illustrating the distal end of
the syringe barrel along with the stationery straight pull core pin
and split core of the injection mold of FIG. 22.
DETAILED DESCRIPTION
[0055] While this invention is satisfied by embodiments in many
different forms, there are shown in the drawings and will herein be
described in detail, preferred embodiments of the invention with
the understanding that the present disclosure is to be considered
exemplary of the principles of the invention and not intended to
limit the invention to the embodiments illustrated. The scope of
the invention will be measured by the appended claims and their
equivalents.
[0056] Referring to FIGS. 1-3, a prior art syringe assembly 20
includes a barrel 21 having an elongate body 22 defining a chamber
23 for retaining fluid. The barrel includes an open proximal end
25, an open distal end 26 including a collar 27 having an internal
thread 28 therein. The barrel also includes an annular sealing
surface 29.
[0057] A prior art needle assembly 30 includes a cannula 31 having
a proximal end 32, and distal end 33 and a lumen (not shown)
therethrough. A hub 35 includes a body portion 36 having a proximal
end 37 and a distal end 38, a passageway therethough. The body
portion further includes an external thread for mating engagement
with the thread in the barrel collar and an annular sealing surface
40 positioned for contacting sealing surface 29 of the barrel.
[0058] A hollow needle shield 41 includes an open proximal end 43
and a distal end 44. The open proximal end of the needle shield
frictionally engages the body portion of the needle hub. The needle
shield is provided to protect the cannula during handling and
attaching the needle assembly to a syringe barrel at which time it
is removed so that the needle and syringe can be used for their
intended purpose.
[0059] Attaching the needle assembly to the barrel involves placing
the proximal end of the needle hub body in the barrel collar and
rotating the needle assembly so that the thread on the needle
assembly engages the thread in the barrel collar. Continued
rotation closes the hub to enter the collar in a distal direction
and continue moving in that direction until the annular sealing
surface 40 on the hub contacts annular sealing surface 29 in the
barrel. Additional rotation will render the interface of the two
annular sealing surfaces fluid tight.
[0060] The most common prior art needle hub and syringe connection
(not shown) involves a frusto-conically shaped tip on the syringe
barrel which engages a frusto-conically shaped recess in the hub.
During installation the rotational forces required increase as the
frusto-conically shaped tip frictionally engages the corresponding
recess in the hub. In the embodiment illustrated, the transition
from relatively unrestricted rotation to sealing is more abrupt. If
the user does not provide enough additional torque after the
sealing surfaces have contacted, the syringe and needle assembly
may leak fluid during the injection process. Excessive force can
damage the fitting or over-stress the fitting so that it may be
compromised over time. A good analogy to the present situation is
the commonly available machine screw and threaded nut assembly.
Without a torque wrench to facilitate the installation, it is left
up to the common sense and experience of the user. In the minority
of cases, some users do not tighten the screw and nut enough and it
subsequently becomes loose or, in the alternative, the user over
tightens the combination until the threads are stripped and the
connection becomes inoperable.
[0061] The present invention overcomes this problem by providing a
syringe and needle assembly that limits the amount of torque that
can be applied when attaching a needle assembly to a barrel and
provides feedback to the user indicating that proper installation
has occurred. Thus providing a uniform sealed connection between
the needle assembly and the barrel over a wide range of users both
weak and strong and experienced and inexperienced.
[0062] Referring to FIGS. 4-7, a syringe and removable needle
assembly 47 having binary attachment features includes an elongate
syringe barrel 48 having a longitudinal axis 49, an inside surface
50 defining a chamber 51 for retaining fluid, an open proximal end
52, an open distal end 53 including a collar 55. A portion of the
collar includes a cylindrically shaped sidewall 56 having an inside
surface 57 and an outside surface 58.
[0063] Needle assembly 61 includes a hub 62 having a body portion
63 including a proximal end 64, a distal end 65 and a conduit
therethrough. The needle assembly further includes a cannula 70
having a distal end 71, a proximal end 72 and a lumen 73
therethrough. The proximal end of the cannula is connected to the
distal end of the hub so that the lumen of the cannula is in fluid
communication with the chamber in the barrel. The cannula may be
integrally formed with the hub as by injection molding using
thermoplastic materials or separately formed, as in this
embodiment, and attached to the hub. In this embodiment, adhesive
74 is used to attach the cannula to the hub, and the cannula is
made of metal, preferably stainless steel.
[0064] The present invention contains structural and functional
features that to avoid the use of excessive torque when attaching
the needle assembly to the syringe barrel and feedback features so
the user knows when the needle assembly is properly attached to the
barrel. In particular, the present invention includes at least one
lug on the collar or on the hub and a ramp and a rest surface on
the other of the collar or the hub. When attaching a needle
assembly to a syringe barrel the lug moves along the ramp until it
reaches the rest surface which prevents the needle assembly from
being secured more tightly than it is at this point.
[0065] In this preferred embodiment, body portion 63 of hub 62
includes an outwardly projecting lug and inside surface 57 of
collar 55 includes a ramp 59 positioned at an acute angle with
respect to the longitudinal axis of the barrel. The ramp terminates
in a rest surface 60 which is preferably, but not necessarily, in a
plane perpendicular to the longitudinal axis of the barrel. Collar
55 includes an aperture 75 therethrough. The rest surface includes
a portion of the periphery of the aperture. Formation of this
aperture will be discussed in more detail herein after.
[0066] When attaching the needle assembly to the barrel, the user
positions the proximal end of the hub inside the collar and rotates
the hub with respect to the barrel so that lug 68 travels along
ramp 59. The hub moves into the collar sealing the hub and the
barrel against leakage, at which time, the lug transitions from the
ramp to the rest surface. At this point, the user experiences a
reduction in the amount of torque necessary to rotate the hub with
respect to the barrel which is a sign that the needle assembly is
properly attached to the barrel. In this preferred embodiment, the
structure provided for sealing the hub to the barrel includes a
distally facing annular surface 76 projecting inwardly into the
open proximal end of the syringe barrel. A proximally facing
annular surface 69 on body portion 63 of the hub is positioned for
contacting distally facing annular surface 76 of the barrel to form
a seal between the hub and barrel and prevent leakage during the
injection process. It should be noted that proximally facing
annular surface 69 on the hub and distally facing annular surface
76 in the barrel need not be aligned exactly at 90.degree. from the
longitudinal axis. A broad range of angles will work with the
angles of 88.degree. to 92.degree. being desired, and 90.degree.
being preferred.
[0067] The rotation of the hub with respect to the barrel during
the attachment process, while the lug travels along the ramp
results in a rotation of the needle assembly of less than
180.degree. with respect to the barrel and preferably less than
100.degree.. When the lug transitions onto the rest surface,
further rotation of the hub with respect to the barrel will not
result in a substantial additional tightening of the seal between
the hub and the barrel.
[0068] Another important feature of the present invention is that
the hub is loosely retained by the barrel during most of the travel
by the lug along the ramp so that the syringe and needle assembly
are incapable of injecting fluids without leaking fluid outside the
lumen until the lug is positioned on the rest surface. This
retention during the movement of the lug along the ramp may be so
slight that the needle assembly could easily become disengaged from
the barrel further alerting the user to the fact that the needle
assembly is not properly attached. Syringe assemblies having
threaded connections between the needle hub and the barrel do not
have this feature.
[0069] The syringe assembly may also include an elongate plunger
rod 81 having a proximal end 82, a distal end 83 and a stopper 84
at the distal end of the plunger rod. The stopper is slidably
positioned in fluid tight engagement with inside surface 50 of the
barrel for dispensing fluid from the chamber through the cannula by
relative motion of the plunger rod with respect to the barrel. The
stopper desirably includes a distally facing projection 85 for
partially occluding the distal end of the barrel when the stopper
is in its distal most position inside the barrel to reduce dead
space.
[0070] As best illustrated in FIG. 7, the collar includes a guide
surface 86 running along and spaced from ramp 59 for guiding the
lug during removal of the needle assembly from the barrel. This
feature is not necessary to practice the present invention but is
preferred since the guide surface also helps align the lugs during
attachment of the needle assembly to the syringe barrel.
[0071] It is also within the purview of the present invention to
include a discontinuity between the ramp and the rest surface for
providing additional tactile feedback to the user during rotation
of the needle assembly with respect to the barrel as the lug
transitions from the ramp to the rest surface. Such a discontinuity
is illustrated as element 87 in FIG. 8 as the lug travels up ramp
59 to rest surface 60, its path is interrupted by discontinuity 87
which, in this configuration, increases the amount of torque
necessary to rotate the needle hub with respect to the barrel until
the lug travels over the discontinuity and falls onto rest surface
60. The discontinuity can take many configurations. Here
discontinuity 87 lengthens the travel of the lug to the rest
surface, however, this is not necessary and any form of detent
which is detectable by the user through touch and/or audible
feedback is within the purview of the present invention and
discontinuity 87 is merely representative of these many
possibilities.
[0072] FIGS. 9 and 10 illustrate another structure for providing
tactile feedback to the user during rotation of a needle assembly
161 with respect to a barrel 148 as a lug 168 transitions from a
ramp 159 to a rest surface 160. In this embodiment, a projection
188 on hub 162 engages a protuberance 189 on collar 155 of the
syringe barrel at the approximate angular position where the lug is
transitioning from ramp 159 to rest surface 160. This feature
provides tactile feedback to the user that the needle assembly is
properly attached to the barrel and no further twisting action is
required. This feature also provides resistance to accidental or
unintentional removal of the needle assembly. Also, the structure
in this embodiment does not modify the ramp and rest surface
configuration so that each function can be optimized without
affecting the other. There are many combinations of projections and
protuberances on the hub and barrel for accomplishing this result
and the outwardly projection 188 and the recessed protuberance 189
illustrated in FIGS. 10 and 11 are merely representative of these
many possibilities, all of which are within the purview of the
present invention.
[0073] FIGS. 11 and 12 illustrate another alternative embodiment of
the present invention. This embodiment hub 262 includes a body
portion 263 having a plurality of lugs 268 extending outwardly
therefrom. Syringe barrel 248 includes a collar 255 having an
inside surface 256. Body portion 263 of the hub further includes an
outwardly projecting annular sealing ring 290 which in this
embodiment is an elastomeric o-ring. When the needle assembly is
attached to the syringe barrel, outwardly projecting annular
sealing ring 290 engages inside surface 256 of the collar to form a
seal between the hub and the barrel to help prevent leakage of the
contents of the barrel through the space between the hub and the
barrel.
[0074] FIG. 13 illustrates a needle assembly 261 having an
alternative outwardly projecting sealing ring 291 on a hub that is
similar to the hub of FIG. 11. In this embodiment, outwardly
projecting annular sealing ring 291 is integrally formed with the
body portion of the hub for sealing engagement with the inside
surface of the collar to form a seal between the hub and the
barrel. In this embodiment, annular sealing ring 291 is a tapered
projection having a base 292 adjacent to body portion 263 of the
hub and a free-end 293. The tapered projection is preferably wider
at its base than at its free-end. A wide variety of materials and
structures can be used to form an annular sealing ring and the
structures illustrated in FIGS. 12-14 are merely representative of
these many possibilities, all of which are in the purview of the
present invention. Needle assembly 261 further includes a cannula
270 having a distal end 271, a proximal end 272 and a lumen 273
therethrough. Hub body portion 263 and cannula 270 are integrally
formed of thermoplastic material. Cannula 270 further includes a
blunt distal tip 274 rather than a sharp distal tip as illustrated
in the embodiment of FIGS. 4-7.
[0075] FIGS. 14 and 15 illustrate another alternative embodiment of
the present invention. In this embodiment syringe barrel 348
includes an open distal end 353 having a collar 355 wherein a
portion of the collar includes a cylindrically shaped sidewall 356
having an outside surface 358. A needle assembly includes a hub 362
having a body portion 363 including a conduit 367 therethrough, an
annular collar 366 preferably having four lugs 368 on its interior
surface. Outside surface 358 of collar 355 preferably includes two
ramps 359 and a rest surface 360 associated with each ramp.
Additional rest surfaces 366 may be provided without ramps. The
ramp is oriented at an acute angle with respect to longitudinal
axis 349 of the barrel, for guiding lugs 368 during needle assembly
attachment, to rest surfaces 360. Hub 362 includes proximally
facing annular sealing surface 369 including an annular proximally
facing skirt 308. The annular proximally facing skirt contacts a
distally facing annular sealing surface in the barrel when the
needle assembly is properly installed. The inclusion of an annular
proximally facing skirt provides a more flexible surface on the hub
for improving the quality of seal between the hub and the distally
facing annular surface of the barrel.
[0076] A syringe and needle assembly of this embodiment functions
similarly to the previous embodiments in that the lug travels along
the ramp during installation of the needle assembly to the barrel
which is complete when the lug rests on rest surface 360. Also
included in this embodiment, is a discontinuity for providing
additional resistance to the movement of the lug as it transitions
from the ramp to the rest surface. Also this discontinuity is
intended to provide additional resistance to the lugs when the
needle assembly is being removed from the syringe barrel. In this
embodiment it is preferred that the rotation of the hub with
respect to the barrel be less than 100.degree. while the lug
travels along the ramp during installation of the needle assembly
to the barrel. Further, the lug and the ramp structure are
configured so that the hub is loosely retained by the barrel during
most of the travel of the lug along the ramps so that the syringe
and needle assembly are incapable of injecting fluid without
leaking fluid outside of the lumen before the lug reaches the rest
area.
[0077] FIGS. 16 and 17 illustrate still another embodiment of the
present invention. This embodiment includes an elongate syringe
barrel 448 having a longitudinal axis 449, an inside surface 450
defining a chamber 451 for retaining fluid, an open distal end 453
including a collar 455. A portion of the collar includes a
cylindrically shaped sidewall 456 having an inside surface 457.
Four lugs 468 are positioned equally distant along inside surface
457 and project inwardly. A needle assembly 461 includes a hub 462
having a body portion 463. Two outwardly projecting ramps 459 and
four outwardly projecting rest surfaces 460 are equally spaced
around the periphery of the body portion of the hub. In this
embodiment, two of the lugs will move up two ramps during
installation of the needle assembly and rest on the rest surfaces.
The other two lugs will rest on rest surfaces 460 that do not have
ramps. The syringe barrel includes a distally facing annular
surface 476 projecting inwardly into the open proximal end of the
barrel. The hub includes a proximally facing annular surface 469
for contacting the distally facing annular surface to form a seal
between the hub and the barrel. This embodiment functions similarly
to the embodiment of FIGS. 4-7.
[0078] FIGS. 18 and 19 illustrate still another embodiment of the
present invention. In this embodiment, an elongate syringe barrel
548 includes a longitudinal axis 549, an inside surface defining a
chamber for retaining fluid, an open proximal end, and open distal
end 553 including a collar 555. A portion of the collar includes a
cylindrically shaped sidewall 556 having an outside surface 558.
Four equally spaced lugs 568 are positioned on outside surface 558
of the collar. A needle assembly includes a hub 562 having a body
portion 563. Body portion 563 includes an annular skirt 566 having
an inside surface. At least two ramps are positioned on the inside
surface and project inwardly. Each ramp terminates in a rest
surface is preferably perpendicular to the longitudinal axis 549.
This embodiment functions similarly to the embodiment of FIGS. 4-7.
The needle assembly is attached to the syringe barrel through
rotation of the hub which engages the lugs causing them to move
along the ramps and onto the rest surfaces wherein the needle
assembly is sealed to the barrel.
[0079] Referring to FIGS. 20 and 21, syringe barrels, such as
barrel 21, are frequently made by injection molding. The process
involves the use of a mold cavity and associated core pins that
define an empty space in the shape of a syringe barrel. Molten
plastic is injected into the space and solidifies through cooling
to form the barrel. Thread cores, like thread core 24, are used to
create threads in syringe barrels. The core is the negative of the
internals of the desired part geometry. Once the part is molded,
the thread core must be removed without smearing or damaging
threads 28. This is achieved by unscrewing the thread core. This
unscrewing action is driven by various gears, racks, hydraulics
and/or motors depending on the mold design. This complexity adds
cost to manufacture the mold. Also since the unscrewing action
cannot be conducted concurrently with other mold actions such as
opening and closing the mold press. Accordingly, the time to unwind
the core adds to the process cycle time increasing the cost to
manufacture the parts. Since barrel molds are usually of a
multi-cavity configuration with many molds containing over 100
cavities, unwinding thread cores adds another degree of complexity
of the tool design which increases the mold costs, cycle time and
tool maintenance requirements.
[0080] An important aspect of the present invention is a method of
making syringe barrels without using an unwinding threaded core. In
accordance with the provisions of the present invention, FIGS. 22
and 23 illustrate a process for molding a syringe barrel, such as
syringe barrel 48 of FIGS. 4, 5 and 7, described in detail
hereinabove. In this embodiment, an injection mold 700 comprises a
fixed body portion 701 defining outside surface of barrel 48, a
proximal core pin 702 defining chamber 51 in the barrel and movable
split cavity 703 defining an outside surface 58 of collar 55. The
movable split cavity also include a raised projection 704 for
forming an aperture in collar 55 and portions of ramp 59 and rest
surface 60. A distal core pin 705 contacts the raised projection on
the split cavity 703 when the mold is closed and defines the
remaining portions of the interior of the collar. Thus, the fixed
portion, the proximal core pin, the movable split cavity and the
distal core pin define a cavity 707 in the shape of the syringe
barrel.
[0081] The method of the present invention further includes
injecting molten thermoplastic material into cavity 707 of the
mold; allowing enough time for thermoplastic material to solidify
enough to allow movement of the barrel with respect to the mold
cavity; opening the split cavity so that the raised projection on
the split cavity is outside of the collar and removing the proximal
core pin and the molded barrel axially from the fixed portion of
the mold without rotating the distal core pin,
[0082] It should be noted that the movable split cavity may also
include a second projection 708. The distal core pin is configured
to cooperate with the second projection to form a second aperture
in the collar and an additional rest surface 366 spaced between
ramps 359 and rest surfaces 360 as illustrated on the syringe of
FIG. 14.
[0083] Also, the raised projection on the split cavity can be
further configured to cooperate with the distal core pin to form a
guide surface 86 in the collar, running along and spaced from the
ramp, for guiding the lug during removal of the needle assembly
from the barrel.
[0084] A wide variety of thermoplastic materials are suitable for
the formation of the syringe barrel using the method of the present
invention. Preferably the thermoplastic material is selected from
the group consisting of polypropylene, polyethylene, polycarbonate,
PET and combinations thereof.
[0085] The method of making a syringe barrel of the present
invention allows thread-like structures (ramps) to be created
without using a threaded core and without producing undercuts. This
is achieved by a moving split cavity and a stationery straight pull
distal core pin. The distal core pin creates the minor diameter of
the ramps, while the major diameter is created by the movable split
cavity. This method of creating the ramps results in the simpler
tool design that can be done with fewer components than with
unwinding methods. Fewer moving parts will require less
maintenance. In addition, the action required to open the split
cavity is done concurrently with the mold opening movement.
* * * * *