U.S. patent application number 10/373531 was filed with the patent office on 2004-08-26 for tamper evident needle guard for syringes.
Invention is credited to Westbye, Lars Tommy.
Application Number | 20040167476 10/373531 |
Document ID | / |
Family ID | 32868730 |
Filed Date | 2004-08-26 |
United States Patent
Application |
20040167476 |
Kind Code |
A1 |
Westbye, Lars Tommy |
August 26, 2004 |
Tamper evident needle guard for syringes
Abstract
A medicine injection device comprises a cartridge having a
cartridge barrel and a plunger having a plunger shaft slidable
within the cartridge barrel. The cartridge may have, e.g., a
pre-filled medicine. The medicine injection device further
comprises a body having a proximal end, a distal end, and a cavity
in which the cartridge barrel is disposed. The proximal end of the
body may optionally form a finger grip. The medicine injection
device further comprises a plunger locking mechanism attached to
the proximal end of the body. The plunger locking mechanism
comprises a member with an aperture slidably engaged with the
plunger shaft. The locking mechanism is configured for preventing
the plunger from being removed from the cartridge barrel. For
example, the plunger shaft may include a locking stop, e.g., a
flange, that engages with the aperture in an interference
arrangement.
Inventors: |
Westbye, Lars Tommy;
(Carlsbad, CA) |
Correspondence
Address: |
ORRICK, HERRINGTON & SUTCLIFFE, LLP
4 PARK PLAZA
SUITE 1600
IRVINE
CA
92614-2558
US
|
Family ID: |
32868730 |
Appl. No.: |
10/373531 |
Filed: |
February 24, 2003 |
Current U.S.
Class: |
604/192 |
Current CPC
Class: |
A61M 5/5086 20130101;
A61M 5/3243 20130101; A61M 5/31511 20130101; A61M 5/5013 20130101;
Y10T 29/4984 20150115; A61M 5/502 20130101; A61M 2005/3139
20130101; A61M 5/3271 20130101; A61M 5/3245 20130101 |
Class at
Publication: |
604/192 |
International
Class: |
A61M 005/32 |
Claims
What is claimed is:
1. A needle guard for syringes, comprising: a medical cartridge
having a cartridge barrel and a plunger, the plunger comprising a
plunger shaft slidable within the medical cartridge; a body having
a proximal end, a distal end, and a cavity configured for receiving
the medical cartridge; and a plunger locking mechanism attachable
to the proximal end of the body, the plunger locking mechanism
comprising a member with an aperture that, when the medical
cartridge is received within the cavity of the body, is configured
to be slidably engaged with the plunger shaft, while preventing the
plunger from being removed from the cartridge barrel.
2. The needle guard of claim 1, wherein the medical cartridge is a
syringe that comprises a needle extending from the cartridge
barrel, and further comprising a shield configured to be slidably
attached to the body between a retracted position for exposing the
needle, and an extended position for substantially covering the
needle.
3. The needle guard of claim 2, wherein the shield is biased to
slide towards the extended position.
4. The needle guard of claim 11, wherein the plunger locking
mechanism comprises a flange through which the aperture extends,
the flange being mountable within the proximal end of the body.
5. The needle guard of claim 4, wherein the proximal end of the
body comprises at least one pair of opposing tab slots, and the
flange comprises at least one pair of opposing tabs matable within
the at least one pair of opposing tab slots.
6. The needle guard of claim 4, wherein the aperture is formed on
an edge of the flange, such that the plunger shaft can be laterally
received within the aperture.
7. The needle guard of claim 1, wherein the cartridge barrel is
pre-filled with a medicine.
8. A medicine injection device, comprising: a medical cartridge
having a cartridge barrel and a plunger, the plunger comprising a
plunger shaft slidable within the cartridge barrel; a body having a
proximal end, a distal end, and a cavity in which the cartridge
barrel is disposed; and a plunger locking mechanism attached to the
proximal end of the body, the plunger locking mechanism comprising
a member with an aperture slidably engaged with the plunger shaft,
the aperture configured for preventing the plunger from being
removed from the cartridge barrel.
9. The medicine injection device of claim 8, wherein the medical
cartridge is a syringe that comprises a needle extending from the
cartridge barrel, and further comprising a shield slidably attached
to the body between a retracted position for exposing the needle,
and an extended position for substantially covering the needle,
wherein the shield is biased to slide towards the extended
position.
10. The medicine injection device of claim 9, further comprising a
frangible cap attached to the shield for preventing access to the
needle.
11. The medicine injection device of claim 8, wherein the proximal
end of the body comprises a finger grip, and the plunger locking
mechanism is attached to the finger grip.
12. The medicine injection device of claim 11, wherein the finger
grip comprises opposing lateral surfaces defining a recess, and the
plunger locking mechanism is received in the recess.
13. A needle guard for a syringe, comprising: a body having a
proximal end, a distal end, and a cavity being adapted to receive a
medical cartridge having a cartridge barrel and a plunger, the
plunger comprising a plunger shaft slidable within the medical
cartridge; and a plunger locking mechanism attached to the proximal
end of the body, the plunger locking mechanism comprising a member
with an aperture slidably engaged with the plunger shaft, the
aperture configured for preventing the plunger from being removed
from the cartridge barrel.
14. The needle guard of claim 13, wherein the medical cartridge is
a syringe that comprises a needle extending from the cartridge
barrel, and further comprising a shield configured to be slidably
attached to the body between a retracted position for exposing the
needle, and an extended position for substantially covering the
needle.
15. The needle guard of claim 13, wherein the proximal end of the
body comprises a finger grip, and the plunger locking mechanism is
attachable to the finger grip.
16. The needle guard of claim 15, wherein the finger grip comprises
opposing lateral surfaces defining a recess, and the plunger
locking mechanism is receivable in the recess.
17. A method for assembling a medicine injection device,
comprising: inserting a medical cartridge into a cavity of a body
through a proximal end of the body; inserting a plunger having a
plunger shaft within the medical cartridge, the plunger shaft
extending from the proximal end of the body; attaching a plunger
locking mechanism to the proximal end of the body, wherein the
plunger locking mechanism comprises an aperture; and slidably
receiving the plunger shaft within the aperture of the plunger
locking mechanism to prevent removal of the plunger from the
medical cartridge.
18. The method of claim 17, wherein the medical cartridge is a
syringe that comprises a needle, and further comprising attaching a
shield to the body, the shield being slidable between a retracted
position for exposing the needle, and an extended position for
substantially covering the needle.
19. The method of claim 17, wherein the plunger locking mechanism
comprises a flange through which the aperture extends, and further
comprising mounting the flange within the proximal end of the
body.
20. The method of claim 19, wherein the proximal end of the body
comprises at least one pair of opposing tab slots, and the flange
comprises at least one pair of opposing tabs, and further
comprising mating the at least one pair of opposing tabs within the
at least one pair of opposing tab slots.
21. The method of claim 17, wherein the proximal end of the body
comprises a finger grip, and further comprising attaching the
plunger locking mechanism to the finger grip.
22. The method of claim 21, wherein the finger grip comprises
opposing lateral surfaces defining a recess, and further comprising
receiving the plunger locking mechanism in the recess.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to safety systems
for syringes or other medical cartridges, and more particularly to
a holder for a syringe that prevents removing or otherwise
tampering with the contents of the syringe.
BACKGROUND
[0002] Medication is often dispensed using a medical cartridge,
such as a syringe, having a barrel with a needle at one end and a
plunger slidably inserted into the other end. Such cartridges are
often referred to as "pre-filled syringes" because they may contain
a specific dosage or volume of medication when they are initially
provided, as compared to conventional syringes that are furnished
empty and filled by the user.
[0003] Alternatively, a medical cartridge may be used, such as a
vial or an ampule, that includes a penetrable seal instead of a
needle on one end of the barrel, and/or a piston rather than a
plunger on the other end.
[0004] Because of the threat of communicable disease, a number of
syringes and adapters have been developed to prevent accidental
needle sticks or inadvertent reuse of needle devices. Many of these
devices, however, are not easy to use or are complicated to
manufacture, resulting in a less effective disposable syringe or
safety device.
[0005] Another consideration with unit dose cartridges is that they
are often made from glass, particularly cartridges for holding
certain vaccines or biotech drugs where concern about
microorganisms or other contaminants is most critical. Glass
cartridges are very fragile and often break during transportation
or use. Some existing adapters may not adequately protect the
cartridge contained therein from such risks. Others provide greater
protection for the cartridge, but may obstruct the professional's
view of the cartridge when the device is being used, hampering
monitoring of the medication being delivered.
[0006] A further consideration with unit dose cartridges is that
they are often filled with extremely expensive medications or drugs
that sometimes cost as much as two thousand dollars per unit dose.
The high cost of the medicine stored in these pre-filled syringes
has created a valuable market for resale of the drugs and
medications. Because of their value, individuals may be tempted to
remove all or part of the expensive medication and replace it with
a less expensive substitute.
[0007] Accordingly, a device that prevents tampering, or provides
evidence of tampering, with a substance inside a pre-filled syringe
would be considered useful.
SUMMARY OF THE INVENTION
[0008] The present inventions are directed to medicine injection
devices, kits, and methods for preventing removal of a plunger from
a cartridge.
[0009] In accordance with one aspect of the present inventions, a
medicine injection device comprises a cartridge having a cartridge
barrel and a plunger having a plunger shaft slidable within the
cartridge barrel. The cartridge may be pre-filled with a medicine
or drug. In this case, the medicine injection device can be fully
assembled by a single entity with the pre-filled cartridge, or may
be supplied to a drug manufacturer in kit form with an empty
cartridge that is then filled with medicine and then assembled by
the drug manufacturer. The medicine injection device further
comprises a body having a proximal end, a distal end, and a cavity
in which the cartridge barrel is disposed. The proximal end of the
body may optionally form a finger grip.
[0010] By way of non-limiting example, the cartridge can be a
syringe that comprises a needle that extends from the cartridge
barrel. In this case, the medicine injection device can further
comprise a shield that is slidably attached to the body between a
retracted position for exposing the needle, and an extended
position for substantially covering the needle. The shield can
optionally be biased to slide towards the extended position by,
e.g., utilizing a spring mechanism. The medicine injection device
may further comprise a frangible cap attached to the shield for
preventing access to the needle.
[0011] The medicine injection device further comprises a plunger
locking mechanism attached to the proximal end of the body. The
plunger locking mechanism comprises a member with an aperture
slidably engaged with the plunger shaft. The locking mechanism is
configured for preventing the plunger from being removed from the
cartridge barrel. For example, the plunger shaft may include a
locking stop, e.g., a flange, that engages with the aperture in an
interference arrangement.
[0012] In the preferred embodiment, the plunger locking mechanism
comprises a flange through which the aperture extends. The flange
is mounted in the proximal end of the body, e.g., within a recess
formed within the lateral surfaces of an optional finger grip. In
this case, the body comprises at least one pair of opposing tab
slots, and the flange may comprise at least one pair of opposing
tabs mated within the opposing tab slots. To facilitate assembly of
the medicine delivery device, the aperture may be formed on an edge
of the flange, such that the plunger shaft can be laterally
received within the aperture.
[0013] In accordance with another aspect of the present inventions,
a method for assembling a medicine injection device comprises
inserting a medical cartridge into a cavity of a body through a
proximal end of the body. The method may include filling the
medical cartridge with medicine.
[0014] By way of non-limiting example, the cartridge can be a
syringe that comprises a needle that extends from the cartridge
barrel. In this case, the method can further comprise attaching a
shield to the body, the shield being slidable between a retracted
position for exposing the needle, and an extended position for
substantially covering the needle. The shield can optionally be
biased to slide towards the extended position by, e.g., utilizing a
spring mechanism. The method can further comprise attaching a
frangible cap to the shield for preventing access to the
needle.
[0015] The method further comprises attaching a plunger locking
mechanism to the proximal end of the holder, wherein the plunger
locking mechanism includes an aperture. The plunger locking
mechanism may comprise a flange through which the aperture extends,
in which case, the method may further comprise mounting the flange
within the proximal end of the body. The preferred method may
comprise mating at least one pair of opposing tabs within the
proximal end of the body with at least one pair of opposing tabs of
the flange. In the preferred method, the plunger shaft may be
laterally received within the aperture, for example, if the
aperture is formed on the edge of the flange.
[0016] The method further comprises receiving the plunger shaft
within the aperture of the plunger locking mechanism to prevent
removal of the plunger from the medical cartridge, while allowing
the plunger shaft to slide within the aperture. For example, the
plunger may comprise a locking stop, e.g., a flange, on the plunger
shaft that engages the aperture of the locking mechanism when an
attempt is made to remove the plunger from the medical
cartridge.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] For a better understanding of the invention, and to show how
it may be carried into effect, reference will be made, by way of
example, to the accompanying drawings, in which:
[0018] FIG. 1 is a perspective view of a medicine injection device
constructed in accordance with a preferred embodiment of the
present inventions;
[0019] FIG. 2 is another perspective view of the medicine injection
device of FIG. 1;
[0020] FIG. 3 is a plunger used with the syringe of the medicine
injection device of FIG. 1;
[0021] FIG. 4A is a perspective view of a body used in the medicine
injection device of FIG. 1;
[0022] FIG. 4B is an enlarged view of the distal portion of the
body of the medicine injection device of FIG. 4A;
[0023] FIG. 5 is a perspective view of a finger grip formed at the
proximal end of the body of FIG. 4A;
[0024] FIG. 6 is a perspective view of a plunger locking mechanism
used in the medicine injection device of FIG. 1;
[0025] FIG. 7 is a plan view of the plunger locking mechanism of
FIG. 6, particularly showing a plunger shaft received by the
plunger locking mechanism;
[0026] FIG. 8 is a plan view of a modified embodiment of the
plunger locking mechanism of FIG. 6, particularly showing a plunger
shaft received by the plunger locking mechanism;
[0027] FIG. 9 is a plan view of another modified embodiment of the
plunger locking mechanism of FIG. 6, particularly showing a plunger
shaft received by the plunger locking mechanism;
[0028] FIG. 10 is a plan view of another plunger locking mechanism
used in the medicine injection device of FIG. 1;
[0029] FIG. 11 is a perspective view of the proximal end of the
medicine injection device of FIG. 1;
[0030] FIG. 12 is a perspective view of a shield used in the
medicine injection device of FIG. 1;
[0031] FIG. 13A is a perspective view of the medicine injection
device of FIG. 1, particularly shown in a retracted state;
[0032] FIG. 13B is an enlarged view of the proximal end of the
medicine injection device of FIG. 13A;
[0033] FIG. 14A is a perspective view of the medicine injection
device of FIG. 1, particularly shown in an extended state;
[0034] FIG. 14B is an enlarged view of an intermediate region of
the medicine injection device of FIG. 14A;
[0035] FIG. 15 is a perspective view of the pre-assembled medicine
injection device of FIG. 1;
[0036] FIG. 16 is a plan view of a pre-assembled plunger locking
mechanism used in the medicine injection device of FIG. 1; and
[0037] FIG. 17 is a plan view of another embodiment of a
pre-assembled plunger locking mechanism used in the medicine
injection device of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] Turning now to the drawings, FIGS. 1 and 2 illustrate a
preferred embodiment of a medicine injection system 5 constructed
in accordance with the present invention. The injection system 5
comprises a syringe 90 and a passive needle guard 10 for holding
the syringe 90. Generally, the passive needle guard 10 includes
four parts, namely a body 20 for receiving and holding the syringe
90, a shield 60 slidably attached to the body 20, a plunger locking
mechanism 12 (FIG. 2), and a frangible cap 80 (FIG. 2). The body
20, shield 60, and locking mechanism 12 are generally molded from
plastic, such as polypropylene, k-resin, or polycarbonate, and are
preferably substantially clear and colorless to facilitate
observation of the syringe 90 received therein. Alternatively they
may be translucent or opaque, and may be colored, such as a latex
color or a flesh tone.
[0039] The preferred cartridge is a pre-filled syringe 90 that
generally has a substantially smooth-walled cylindrical barrel 92,
a distal end or hub 94 including a hypodermic needle 95, a
frangible needle cover or cap 80, a proximal end 93 (FIG. 15)
having a flange 96, and a plunger 98 that is inserted into the
barrel 92 at the proximal end 93. The flange 96 may have a
sufficiently large width to provide a finger grip for the syringe
90, or may simply be a small lip to facilitate manufacturing, for
example, on a filling line.
[0040] As best seen in FIG. 3, the plunger 98 includes a shaft 97
having a thumb pad 99 on its proximal end and a flange 100 and a
threaded tip 103 on its distal end. The plunger 98 further
comprises a piston 101 that includes a threaded bore (not shown)
that is adapted to screw onto the threaded tip 103 of the plunger
shaft 97 and abut against the distal surface of the flange 100. In
a preferred embodiment, the syringe 90 is filled with a
predetermined dose of medication through the proximal end 93, and
then the plunger 98 is slidably inserted into the proximal end 93
to substantially seal the barrel 92. Alternatively, other syringes
or cartridges may be provided that include a seal (not shown) on
the distal end instead of a distal hub 94 and needle 95.
[0041] Turning to FIGS. 4A, 4B and 5, the body 20 has opposing side
rails 28 defining two elongate openings or windows 36 extending at
least partially between a proximal end 22 and a distal end 24 of
the body 20. The two side rails 28 generally have a "C" shape
defining a cavity 26 extending axially from the proximal end 22 to
the distal end 24 of the body 20. Alternatively, instead of the
side rails 28, the body 20 may include a substantially rectangular
body having four side walls (not shown). If a four-walled body is
provided, it may be desirable to provide one or more elongate
openings or windows in one or more of the side walls, preferably in
two walls on opposite sides of the body 20.
[0042] The inside surfaces 30 of the rails 28 are preferably
concave, conforming substantially to the outer diameter of a
conventional pre-filled syringe 90. Alternatively, guide rails,
resilient ribs, and the like (not shown) may be provided on the
inside surface 30 to facilitate insertion of a cartridge into the
cavity 26 and/or to provide lateral support for a syringe received
therein. U.S. Pat. No. 6,344,032, issued to Perez et al., the
disclosure of which is expressly incorporated herein by reference,
discloses exemplary resilient rib structures that may be provided
within the body 20. The outer surfaces of the side rails 28 define
a substantially rectangular cross-section for the body 20,
providing a substantially rigid structure for protecting the
syringe 90 received within the body 20. Alternatively, outer
surfaces of the side rails 28 may define other cross-sectional
shapes, e.g., round or oval.
[0043] A substantially rigid collar 32 (FIG. 4A) is molded on the
distal end 24 of the body, the collar 32 preferably having a
substantially annular shape. The collar 32 defines an opening 34
for allowing a needle 95 and the frangible cap 80 on the syringe 90
(best seen in FIGS. 1 and 2) received in the cavity 26 to extend
distally beyond the body 20. The opening 34 preferably has a
diameter smaller than the cavity 26, such that the distal end 24
substantially retains the syringe inside the cavity 26 preventing
distal movement. Alternatively, the distal end 24 may be tapered or
otherwise partially obstructed for engaging the distal end of the
syringe 90 and/or preventing distal movement of the syringe 90.
Stop tabs 38 may be molded directly on the distal end 24 of the
body 20, preferably on two opposite sides of the distal end 24, or
alternatively, may be provided on a cantilever member (not shown),
such as that disclosed in U.S. Pat. No. 6,030,366, issued to
Mitchell, the disclosure of which is expressly incorporated herein
by reference.
[0044] A finger grip 50 is molded on the proximal end 22 of the
body 20, and includes a pair of wing-like members or flanges 52
generally defining a "T" shape. Each wing-like member 52 includes a
distal surface or finger ledge 54, and an outer gripping surface 56
extending proximally from the outer edge 54a of the finger ledge
54. The outer gripping surface 56 may include a lip, grooves, or
other irregularities (not shown) protruding radially from its
proximal end or set in the surface 56, for example, to facilitate a
user holding the finger grip 50. Lateral surfaces 55 extend
proximally from the finger ledges 54 between the gripping surfaces
56, thereby defining a recess 51 communicating with the cavity 26
in the body 20. Alternatively, the recess 51 may be eliminated
and/or the finger grip 50 may be shortened, for example, to simply
be a flat transverse flange for accommodating shorter syringes or
cartridges (not shown).
[0045] A catch or tab 48 may be molded or otherwise extend from one
of and preferably both of the lateral surfaces 55 of the finger
grip 50. Alternatively, the catch 48 may be provided on the
proximal end 22 of the body 20 adjacent the finger grip 50 (not
shown). The catch 48 engages the tabs 76 on the latch members 74 as
described further below.
[0046] In a preferred embodiment, a locking mechanism is provided
on the finger grip 50 and/or on the proximal end of the body 20 for
engaging a flange 96 of the syringe 90 (best seen in FIGS. 1 and 2)
received in the cavity 26, and thereby substantially securing the
syringe within the body 20. Preferably, the locking mechanism
includes a plurality of locking detents 58 at least partially
defining an aperture or slot 57 that are formed in lateral surfaces
55 of the finger grip 50 for receiving the flange 96 therein.
Alternatively, other locking mechanisms may be provided on the
proximal end 22 of the body 20, such as those disclosed in U.S.
Pat. No. 6,344,032, the disclosure of which has been previously
incorporated herein by reference. In a further alternative, other
known mechanisms may be used to secure a syringe within the body
20, such as locking detents or a collet mechanism (not shown) on
the distal end 24 of the body 20.
[0047] One or more sets of detent pockets may be molded into the
body 20 to facilitate securing the relative movement of the shield
60 and body 20. In a preferred embodiment, a set of proximal detent
pockets 40 is provided adjacent the finger grip 50, and a set of
distal detent pockets 42 is provided at a more distal location on
the body 20. Preferably, the proximal detent pockets 40 have
sloping distal edges 40a and substantially blunt proximal edges
40b. The distal detent pockets 42 also have substantially blunt,
and preferably oblique, proximal edges 42b.
[0048] One or more sets of tab openings 14 are molded into the body
20 to facilitate securing the plunger locking mechanism 12 to the
body 20, as will be described in further detail below. In a
preferred embodiment, the tab openings 14 are molded into the
lateral surfaces 55 of the finger grip 50.
[0049] Referring to FIGS. 2, 5 and 6, in the illustrated
embodiment, the plunger locking mechanism 12 comprises a semi-rigid
flange 110 mounted within the recess 51 of the finger grip 50. The
shape of the flange 110 conforms to the shape of the recess 51,
such that it fits snugly within the finger grip 50. The locking
mechanism 12 further comprises tabs 112 that mate with
corresponding tab openings 14 on the finger grip 50. The locking
mechanism 12 further comprises an aperture 114 formed within the
flange 110 for receiving the shaft 97 of the plunger 98. In the
illustrated embodiment, the aperture 114 is formed on an edge 116
of the flange 110, such that the flange 110 has a C-shape. As will
be described in further detail below, this facilitates the assembly
process by allowing the locking mechanism 12 to laterally receive
the shaft 97 of the plunger 98.
[0050] The aperture 114 is configured to allow the plunger 98 to
slide within the cavity 26 of the body 20, while preventing the
plunger 98 from being entirely removed from the syringe 90.
Specifically, the flange 100 at the distal end of the plunger shaft
97 serves as a stop that engages with the sides of aperture 114 in
an interfering arrangement when an attempt is made to pull the
plunger 98 out of the body cavity 26. In the illustrated
embodiment, the diameter of the plunger shaft 97 is less than the
diameter of the plunger flange 100. The aperture 114, which is
semi-circular or oval, has a diameter that is greater than the
diameter of the plunger shaft 97, thereby allowing the plunger 98
to slide relative thereto, but less than diameter of the plunger
flange 100 (shown in dashed lines in FIG. 7), thereby preventing
the plunger 98 from being pulled through the aperture 114. Thus,
the plunger locking mechanism 12 prevents the removal of the
plunger 98 from the pre-filled syringe 90, thereby preventing
access to the contents of the syringe 90 via the open end of the
syringe 90 and the resultant tampering of medication or drugs in
the syringe 90.
[0051] It should be noted that although the aperture is
semi-circular or oval, other cross-sectional shapes can be used.
For example, FIG. 8 illustrates an aperture 118 that has a
cross-sectional profile in the shape of a cross, which matches the
cross-sectional shape of the plunger shaft 97, thereby allowing it
to slide relative thereto, while preventing the circular plunger
flange 100 from being pulled through it. In this case, the flange
110 can be twisted to allow lateral receipt of the plunger shaft 97
during assembly. It should also be noted that in certain
arrangements, the apertures 114/118 need not be situated on the
edge 116 of the flange 100. For example, FIG. 9 illustrates a
closed circular aperture 122. In this case, if the plunger flange
100 is removably attached to the plunger shaft 97, e.g., via a
threaded engagement, the plunger shaft 97 can be axially received
through the closed aperture 122 before these components are
attached to the plunger shaft 97.
[0052] Alternative embodiments of other plunger locking mechanisms
and their arrangement with the body 20 are contemplated by the
present inventions. For example, FIGS. 10 and 11 illustrate a
plunger locking mechanism 16 that can be mounted within the slot 57
of the finger grip 50. The locking mechanism 16 comprises a flange
124 and an aperture 126 formed through the flange 124. As with the
previously described aperture 114, the aperture 126 is configured
to laterally receive the shaft 97 of the plunger 98. The flange 124
comprises opposing tabs 128 that snugly fit within the opposing
slots 57 between the flange 96 of the syringe 90 (when mounted
within the slot 57) and the blunt distal edges 58b of the locking
detents 58. Thus, the plunger locking mechanism 16 prevents the
removal of the plunger 98 from the syringe 90, thereby preventing
access to the contents of the syringe 90 via the open end of the
pre-filled syringe 90 and the resultant tampering of medication or
drugs in the pre-filled syringe 90.
[0053] Turning to FIG. 12, the shield 60 is a tubular member
adapted to slidably fit on the body 20, preferably having a
substantially rectangular interior shape that conforms to the
exterior shape of the body 20. The shield 60 includes four side
walls 61a, 61b, an open proximal end 62, and an open distal end 63.
The shield 60 and body 20 are slidable in relation to one another
between an unguarded post, when the needle 95 is exposed (FIG.
13A), and a guarded post, when the needle 95 is substantially
covered (FIG. 14A), as explained in further detail below.
[0054] One or more latch members or fingers 74 extend proximally
from the shield 60, preferably molded to each of the assembly tabs
72. Alternatively, the latch members 74 may be made as separate
pieces that are bonded or otherwise attached to the shield 60, for
example, to the outside of the assembly tabs 72, using an adhesive
and the like. Each latch member 74 includes an inwardly disposed
catch or tab 76 located on an intermediate portion of the latch
member 74 between the assembly tab 72 and a tip 78 of the latch
member 74. The latch members 74 are preferably provided from a
substantially flexible material such that they are resiliently
deflectable for deflecting the intermediate portion radially
outward, and thereby disengaging the catch 76 from the mating catch
48 on the body 20, but are biased to return inwards to promote
engagement with the mating catches 48 on the body 20, as described
further below.
[0055] A plurality of detent arms 70, preferably in opposing pairs,
and a plurality of detents 71 are integrally molded directly onto
or otherwise attached to the side walls 61b. The detents 71
preferably have shapes corresponding substantially to the shapes of
the detent pockets 40, 42 in the body 20. Distal edges 71a of the
detents 71 are preferably ramped to facilitate slidable engagement
with the distal surfaces 40a of the proximal detent pockets 40.
Proximal edges 71b (FIG. 14B) of the detents 71 are substantially
blunt, and preferably oblique, for positively engaging the proximal
edges 42b of the distal detent pockets 42 and locking the shield 60
in an extended position, as described further below. Additional
information on detents and detent pockets for use with the present
invention are described in the Mitchell patent referenced above. In
addition, the detent arms 70 may include indents (not shown) for
controlling the flexural strength of the detent arms 70, as the
arms 70 may vary in size and thickness in embodiments adapted to
accommodate a variety of syringes.
[0056] At least one wall 61a, and preferably the two opposite walls
61a, include an elongate opening or window 64 therethrough. The
windows 64 may facilitate observation of the syringe 90 received in
the body 20, and also provide a traveling slot for the stop tabs 38
on the body 20. The windows 64 have a proximal edge 66 and a distal
edge 68 defined by the wall 61a that limit the relative movement of
the shield 60 to the body 20, as explained below. Alternatively,
the windows 64 may be divided by a cross-member (not shown) molded
into the wall 61a that extends transversely across the window 64 if
it is desired to further limit movement of the shield 60.
[0057] Optionally, the side walls 61a, 61b may include wings, a
ring, or similar finger holds (not shown) extending radially from
the shield 60 to ease movement of the shield 60 in relation to the
body 20. In addition, the side walls 61a, 61b may provide a flat
surface onto which a label may be applied, for example to identify
the drug, medication, or other fluid contained within the
pre-filled syringe 90 received within the guard 10, or an embossed
pattern may be molded, possibly including a name or a logo.
[0058] The shield 60 has a distal opening 65 through which the
distal hub 94 of the syringe 90 and needle 95 extend. The distal
opening 65 is generally circular and has a diameter larger than
that of the needle 95 on the syringe 90, and may be provided with a
variety of diameters, for example, larger than the cartridge barrel
92 and/or hub 94, or configurations to facilitate use of the
syringe 90. For example, the diameter of the opening 65 may be
sufficiently large to accommodate a luer adapter (not shown) or
other alternative distal tip to be provided on the syringe 90 or
attached to the hub 94. Most preferably, the opening 65 has a
diameter sufficiently small to minimize the risk of accidental
sticks, for example, to prevent a finger from being directed into
the shield 60 after use.
[0059] A spring mechanism (not shown) may be coupled to the body 20
and the shield 60 to bias the shield 60 towards an extended
position. U.S. patent application Ser. No. 09/566,224, filed May 5,
2000, the disclosure of which is expressly incorporated herein by
reference, describes various spring arrangements that can be
incorporated into the guard 10.
[0060] Referring back to FIGS. 1 and 2, the cap 80 is frangibly
attached to or otherwise extends from the distal end 63 of the
shield 60 to prevent access to the contents of the syringe 90
and/or prevent exposing the needle 95 of the syringe 90. In a
preferred embodiment, the cap 80 is attached by a weakened region
81 (shown in FIG. 2), which may be a perforated seam or otherwise a
relatively thin region that extends from a distal end of the cap 80
to a proximal end of the cap 80. In the preferred embodiment, the
cap 80 and shield 60 may be molded as a single piece with a
weakened region 81 between them. In any event, the weakened region
81 preferably allows for quick, easy, and clean break away of the
cap 80 from the shield 60, while preventing the cap 80 from being
reattached to the shield 60. Thus, this arrangement will provide an
immediate and easily recognizable indication that the cap 80 has
been removed from the assembly, thereby preventing undetected
access to the contents of the syringe 90 and the resultant
tampering of medication or drugs in the pre-filled syringe 90 via
the needle 95.
[0061] Referring to FIGS. 12, 13A and 13B, the passive needle guard
10 is generally provided to the user with body 20, shield 60,
plunger locking mechanism 12, and frangible cap 80 (not shown). In
the retracted position, the tabs 76 on the latch members 74
substantially engage the mating catches 48 on the body, thereby
securing the shield 60 in the retracted position against the bias
provided by a spring mechanism such as disclosed in U.S. patent
application Ser. No. 09/724,657, filed Nov. 28, 2000, the
disclosure of which is expressly incorporated herein by reference.
In addition, the detents 71 may be received in the proximal detent
pockets 40, thereby providing additional security to hold the
shield 60 in the retracted position. Alternatively, the proximal
detent pockets 40 may be used merely to receive the detents 71 and
thereby allow the detent arms 70 to return to a relaxed state,
rather than extending outward along the outer surface of the body
20. In a further alternative, the proximal detent pockets 40 may
not be needed and may be eliminated.
[0062] Referring to FIGS. 4A and 12, to assemble the passive needle
guard 10, the distal end 24 of the body 20 is inserted into the
open proximal end 62 of the shield 60, with the window 36 in the
body 20 aligned with the side wall 61a of the shield 60 having the
window 64 therein. A spring (not shown) may be positioned within a
passage and/or secured to the body 20 and shield 60 in a
conventional manner. As the body 20 is inserted, the stop tab 38
engages a tapered interior edge (not shown) of the assembly tab 72
on the shield 60, allowing the stop tab 38 to pass under the side
wall 61a. After the stop tab 38 passes under the side wall 61a, it
may enter the window 64 where it may freely travel.
[0063] The stop tab 38 and window 64 cooperate to allow the shield
60 to slidably move in relation to the body 20, but substantially
define the limits of their relative movement. The shield 60 may
slide proximally and distally until the stop tab 38 abuts a distal
edge 68 and a proximal edge 66 of the window 64, respectively.
Specifically, when the stop tab 38 engages the distal edge 68 of
the window 64, the shield 60 is in the retracted or unguarded
position (FIG. 13A). When the stop tab 38 engages the proximal edge
66 of the window 64, the shield is in the extended or guarded
position (FIG. 14A).
[0064] While the stop tab 38 and window 64 cooperate to limit the
movement of the shield 60, the catches 48, 76, and the cooperating
detents 71 and detent pockets 40, 42 on the shield 60 and body 20
also cooperate to hold the shield 60 either in the retracted
position or in the extended position. During assembly, the latch
members 74 may be deflected radially outwardly to avoid contact
between the catches 76 thereon and the mating catches 48 on the
body 20. Similarly, the detent arms 70 may be deflected radially
outwardly such that the detents 71 do not engage the distal detent
pockets 42 while the shield 60 is directed to the retracted
position.
[0065] As best seen in FIGS. 13A and 13B, once the shield 60 is
fully retracted, the latch members 74 and the detent arms 70 are
released, whereupon they resiliently return inward such that the
catches 76 on the latch members 74 engage the mating catches 48 on
the body 20, and the detents 71 engage the proximal detent pockets
40. In the retracted position, the stop tab 38 also abuts the
distal edge 68 of the window 64, thereby preventing further
proximal movement of the shield 60. The sloping distal edges 71a of
the detents 71 engage the sloping distal edges 40a of the proximal
detent pockets 40 on the body 20, thereby assisting the cooperating
catches 48, 76 in preventing the shield 60 from moving distally.
However, the frictional resistance between the sloping distal edges
71a, 40a of the detents 71 and the proximal detent pockets 40 may
be overcome by a distal force, such as that provided by the spring
mechanism when the catches 48, 76 are released, as described
further below. In addition, the slope of the sloping edges 40a, 42a
may be adjusted to increase or decrease the frictional resistance,
for example, to slow the shield 60 down when it initially advances
from the retracted position.
[0066] Once assembled, the passive needle guard 10 is ready to
receive a cartridge, such as the pre-filled syringe 90. The syringe
90 is preferably pre-assembled within the passive needle guard 10
before being furnished to a user, for example, at the time of
manufacturing the passive needle guard 10. In a preferred
embodiment, the syringe 90 may be pre-assembled by measuring out a
dose of medication into the syringe 90, and then placing the
plunger 98 within the barrel 92 of the syringe 90. Although the
syringe 90 shown is the preferred medication delivery system that
may be used with the passive needle guard 10, it will be
appreciated that the passive needle guard 10 may be modified for
use with other pre-filled-or unit dose delivery systems, and that
the term cartridge may include other such known systems. For
example, the finger grip 50 on the proximal end 22 of the body 20
may be replaced with a plunger and plug assembly (not shown), such
as that disclosed in U.S. Pat. No. 5,624,400, issued to Firth et
al., the disclosure of which is expressly incorporated herein by
reference. In addition, the collar 32 on the distal end 24 of the
body 20 may be replaced with a double-ended needle cannula, such as
that disclosed in the Firth et al. patent.
[0067] The distal end or hub 94 of the syringe 90 is inserted into
the recess 51 of the finger grip 50 and the open proximal end 22 of
the body 20 until it enters the cavity 26 and progresses distally
towards the distal end 24 of the body 20. Once fully encapsulated,
the distal end 94 of the syringe 90 may simply abut the distal end
24 of the body 20, or alternatively the distal end 94 may partially
enter the opening 34 and engage the collar 32, thereby providing
additional protection from lateral movement of the syringe 90.
[0068] Before the syringe 90 is inserted into the body 20 or before
the flange 96 contacts the latch members 74, the latch members 74
may be deflected radially outward, while securing the shield 60 in
the retracted position, for example, manually or in a jig or other
mechanism. Thus, any contact between the latch members 74 and the
syringe 90 may be avoided until the flange 96 passes the tips 78 of
the latch members 74 and enters the recess 51 of the finger grip
50. The latch members 74 may then be released such that the catches
76 again engage the mating catches 48 on the body 20.
[0069] Alternatively, the syringe 90 may be inserted into the body
20 while the shield 60 is extended and the latch members 74 are
consequently positioned distally away from the recess 51 into which
the syringe 90 is to be inserted. Once the syringe 90 is fully
inserted, the detents 71 may be disengaged from the distal detent
pockets 42 and the shield 60 may be directed to the retracted
position. In another alternative embodiment, an intermediate stop
(not shown) may be provided to hold the shield 60 in a position
between the extended and retracted positions, wherein the latch
members 74 may be located distally away from the recess 51 into
which the syringe 90 is to be inserted. Once the syringe 90 has
been inserted, the shield may be directed to the retracted position
where the catches 48, 76 may engage each other. The intermediate
stop may then be disabled, for example, by being deflected or
broken off, thereby preventing the intermediate stop from
subsequently interfering with advancement of the shield 60 from the
retracted position to the extended position.
[0070] Referring further to FIGS. 1 and 2, as the syringe 90
becomes fully encapsulated within the cavity 26, the flange 96 of
the syringe 90 contacts the locking detents 58 on the finger grip
50. The locking detents 58 have tapered proximal edges 58a,
allowing the syringe 90 to be directed further distally, the flange
96 moving the locking detents 58 aside and entering the slot 57.
The locking detents 58 have substantially blunt distal edges 58b
that prevent the syringe 90 from being removed proximally from the
slot 57, thereby substantially permanently locking the syringe 90
into the body 20, and preventing axial (i.e. proximal and/or
distal) movement of the syringe 90 within the passive needle guard
10.
[0071] Once the syringe 90 is locked into the passive needle guard
10, the needle 95 and its cap 80 extend through the opening 34 on
the collar 32 and the opening 65 on the distal end 63 of the shield
60. Preferably, the length of the shield 60 is substantially
coextensive with the barrel 92 of the syringe 90, allowing the
needle 95 to extend beyond the distal end 63 of the shield 60, but
protecting the hub 94 of the pre-filled syringe 90.
[0072] Once the syringe 90 is firmly received into the guard 10,
the plunger locking mechanism 12 is mounted within the recess 51 of
the finger grip 50 and is placed into a locking arrangement with
the plunger 98 to prevent removal of the plunger 98 from the
syringe 90. Specifically, the plunger shaft 97 is laterally
received within the aperture 114 of the locking mechanism 12, and
the tabs 112 on one edge 116 of the flange 110 are inserted into
the mating tab openings 14 within the lateral surface 55 of the
finger grip 50, as illustrated in FIG. 16. With the plunger shaft
97 still received within the aperture 114 of the locking mechanism
12, the other edge 116 of the flange 110 is then distally rotated
around the hinge formed by the already mated tabs 112 and tab
openings 14 until the tabs 112 on the other edge are inserted into
the mating tab openings 14 within the other lateral surface 55 of
the finger grip 50. In this manner, the plunger 98 will be locked
within the syringe 90.
[0073] In the case of the locking mechanism 16, the plunger shaft
97 is laterally received within the aperture 114 of the locking
mechanism 12, and one of the tabs 128 of the flange 124 is inserted
into the corresponding slot 57 within the lateral surface 55 of the
finger grip 50, as illustrated in FIG. 17. With the plunger shaft
97 still received within the aperture 126 of the locking mechanism
16, the other tab 128 of the flange 124 is then distally rotated
around the hinge formed by the already mated tab 124 and slot 57
until the other tab 112 is inserted into the opposite slot 57
within the other lateral surface 55 of the finger grip 50. In this
manner, the plunger 98 will be locked within the syringe 90.
[0074] Returning to FIGS. 13 and 14, the syringe 90 encapsulated
within the passive needle guard 10 may then be used in a
conventional manner to deliver medication in the barrel 92. The
needle cap 80 (shown in FIGS. 1 and 2) is first removed from the
distal end 63 of the shield 60 by tearing or breaking the cap 80
away from the shield 60 at the weakened region 81. The needle 95
may then be inserted into the patient (not shown), and the
medication delivered by depressing the plunger 98 distally. As may
be seen from FIG. 1, the windows 64, 36 may facilitate observation
of the barrel 92 of the syringe 90, allowing the user to monitor
delivery of the medication therein.
[0075] The plunger 98 may be depressed until the thumb pad 99
contacts the tips 78 of the latch members 74. As the plunger 98 is
depressed further, the thumb pad 99 causes the latch members 74 to
compress axially and thereby deflect radially outwardly until the
catches 76 are disengaged from the mating catches 48 on the body
20.
[0076] With the catches 48, 76 disengaged, the spring mechanism
biases the shield 60 distally, whereupon the shield 60 may
automatically advance towards the extended position, shown in FIG.
14. The latch members 74 merely slide along the body 20 as the
shield 60 advances. Thus, the shield 60 may be automatically
activated and advanced without requiring any action from the user
other than depression of the plunger 98. Because of the
predetermined location of the distal detent pockets 42, when the
stop tab 38 reaches the proximal edge 66 of the window 64, the
detents 71 substantially simultaneously enter the distal detent
pockets 42. The blunt or oblique proximal edges 71b of the detents
71 engage the similarly shaped proximal edges 42b of the distal
detent pockets 42, thereby preventing the shield 60 from being
moved proximally. In an alternative embodiment, the body 20 may
include pockets (not shown) for receiving the catches 76 on the
latch members 74 when the shield 60 reaches the extended position,
thereby further securing the shield 60 from proximal movement.
Furthermore, because the stop tab 38 abuts the proximal edge 66 of
the window 64, the shield 60 may not be moved further distally.
Thus, the shield 60 is thereby substantially permanently locked in
the extended position.
[0077] As the shield 60 advances to the extended position, the
distal end 63 of the shield 60 passes over the needle 95, covering
the needle 95. Once the shield 60 is locked in the extended
position, the needle 95 may no longer be accessible, thereby
substantially eliminating the risk of accidental sticks, and
preventing reuse of the syringe 90. The guard 10 and syringe 90 may
then be disposed of in a conventional manner.
[0078] A useful feature of the passive needle guard 10 is that the
latch members 74 and/or the plunger 98 have predetermined relative
lengths to activate the shield 60 at a desired time during the
plunger stroke. For example, it may be desirable to activate the
shield 60 early in the stroke such that the shield 60 is activated
and advanced into contact with the patient's skin. Upon removal of
the needle from the patient, the shield 60 simply slides completely
to the extended position, automatically covering the needle 95 as
it is withdrawn from the patient. Alternatively, the latch members
74 and/or plunger 98 may be configured to activate the shield 60
only upon complete depression of the plunger 98. In a further
alternative, the plunger 98 may include a radial portion, such as a
tab or an annular rib (not shown), at an intermediate location
thereon. The radial portion may engage and deflect the latch
members 75 during depression of the plunger 98, similar to the
thumb pad 99 described above.
[0079] While the invention is susceptible to various modifications,
and alternative forms, specific examples thereof have been shown in
the drawings and are herein described in detail. It should be
understood, however, that the invention is not limited to the
particular forms or methods disclosed, but to the contrary, the
invention is to cover all modifications, equivalents, and
alternatives falling within the spirit and scope of the appended
claims.
* * * * *