Syringe needle abstract
A hypodermic syringe needle assembly for prefilled syringes in
which the means for attaching the needle assembly to a syringe,
the cover for the portion of the needle used for injecting and the
cover for the portion of the needle used to activate the syringe
is a unitized structure. This structure is breakable at a specific
break point when the prefilled syringe is activated for use and
breakable at another specific break point to expose the injection
needle.
Syringe needle claims
What is claimed is:
1. A unitized cover for a hypodermic syringe needle having an outer
end, an inner end, and a middle section comprising; a first cover
for said outer end, a second cover for said inner end, a third cover
for said middle section, a first breakable means connecting said
first cover and said third cover, a second breakable means connecting
said second cover and said third cover, said first breakable means
and said second breakable means connecting said first cover, said
second cover, and said third cover to form a unitized structure.
2. A unitized cover for a hypodermic syringe needle according to
claim 1 including mounting means for mounting said hypodermic needle
to said third cover, deflectable means associated with said third
cover such that said deflectable means are deflected by said mounting
means.
3. A unitized cover for a hypodermic syringe needle according to
claim 2 including retaining means associated with said second cover
and said deflectable means to limit movement of said second cover
with respect to said third cover when said second breakable means
are broken.
4. A unitized cover for a hypodermic syringe needle according to
claim 1 including mounting means for mounting said unitized cover
to the hypodermic syringe.
5. A needle assembly attachable to a syringe body comprising a
cannula having an outer section, an inner section, and a center
section, a first cover member over said inner section of said cannula,
attaching means for attaching said first cover member to said syringe
body, a second cover member covering said middle section of said
cannula and breakable means connecting said second cover member
to said first cover member.
6. A needle assembly according to claim 5 including mounting means
secured to said center section of said cannula for mounting said
cannula to said second cover member.
7. A needle assembly according to claim 5 including deflectable
members attached to said second cover member retaining means on
said first cover member engageable with said deflectable members
such that said second cover member can only move in one axial direction
when said breakable means is broken.
8. A needle assembly according to claim 7 including a cannula
mounting element, deflecting means on said cannula mounting element
to deflect said deflectable members in spring pressure engagement
with said first cover.
9. A needle assembly attachable to a syringe body comprising, a
cannula having an outer section, an inner section and a center section,
a first cover member covering said outer section, a second cover
member covering said center section, and breakable means connecting
said first cover member to said second cover member to form a unitized
structure.
10. A needle assembly according to claim 9 including a cannula
mounting member for mounting said cannula in said second cover member.
11. A needle assembly according to claim 10 including openings
in said breakable means, a projection on said cannula mounting member,
a cavity in said first cover member, said projection and said cavity
forming a sterility barrier for said outer section of said cannula.
12. A needle assembly attachable to a syringe body comprising,
a hollow cannula pointed at an outer end and an inner end, an assembled
inactive position for said cannula, an operated active position
for said cannula, a unitized cover for said hollow cannula, an outer
section of said unitized cover, an inner section of said unitized
cover and a center section of said unitized cover, a first breakable
member between said inner cover and said center cover, a second
breakable member between said outer cover and said center cover,
said first breakable member breakable on movement of said cannula
from said inactive position to said active position, said second
breakable member breakable for exposing said outer end of said cannula.
13. A needle assembly attachable to a syringe body according to
claim 12 including attaching means on said inner cover to attach
said needle assembly to said syringe body.
14. A needle assembly attachable to a syringe body according to
claim 13 including mounting means for said cannula, deflecting
means on said center cover, said mounting means deflecting said
deflecting means against said inner cover when said mounting means
is assembled in said center cover.
15. A needle assembly according to claim 14 including restraining
means on said inner cover and restraining elements on said deflecting
means to restrict movement of said cannula for movement from said
inactive position to said active position only.
Syringe needle description
BACKGROUND OF INVENTION
In disposable hypodermic syringe, U.S. Pat. No. 4221218 a syringe
closing member, a needle holder and a cover were specifically described.
These components are fabricated as individual pieces, assembled
to each other to form an assembly and then fastened to the syringe
body. All these manufacturing steps are expensive and are susceptible
to rejects. The components described in the referenced patent provide
for sterility to airborne contaminants because of the Pasteur principle
of Tortuous Pathway. The syringe would not maintain sterility if
submersed in water or other fluids. As a result, to reduce cost
and make the needle assembly sterile under all conditions it is
desirable that the needle assembly be made with as few parts as
possible and that there be no voids or openings between any of the
parts making up the needle assembly. Since the needle should be
protected from damage in handling it is important that the needle
assembly should also act as a mechanical protection for the needle.
In most prefilled syringes the needle does not contact the fluids
of the syringe when the syringe is in storage or shipment. To use
the syringe one end of the needle pierces a seal between the needle
and the fluid to allow transfer of the fluid through the needle
to the person or animal being injected. The activation of the needle
from the non-activated position with respect to the syringe to the
activated position should be capable of being performed with the
minimum amount of motion and the minimum amount of effort. Since
the sterility of that portion of the needle that pierces the seal
and the portion of the needle that is injected into a person or
animal is very ctitical, the needle covers should never accidentally
fall off or dislodge from the assembly and expose any part of the
needle. In existing needle cover assemblies extremely close tolerances
must be held between mating parts to assure that accidental separation
does not take place and that excess forces are not required to operate
the syringes. As a result the number of parts required, the assembly
of the parts and the accuracy of the parts of syringe needle assemblies
that are available today are costly and still do not provide all
of the desired features of an ideal assembly.
SUMMARY OF INVENTION
It is therefore a first object of this invention to provide a hypodermic
syringe needle assembly with as few parts and as few assembly operations
as possible.
It is a further object of this invention to provide a hypodermic
syringe needle assembly in which the components of the assembly
insure normal sterility.
It is a further object of this invention to provide a hypodermic
syringe needle assembly which is capable of maintaining sterility
even if immersed in a fluid.
It is a further object of this invention to provide a hypodermic
syringe needle assembly which makes activating of a prefilled syringe
easy to accomplish.
It is a further object of this invention to provide a hypodermic
syringe needle assembly which is reliable and can be provided at
a minimum cost.
These and other objects of this invention will become apparent
from the following specifications and drawings which form part of
this disclosure. This invention therefore consists of unique features
of construction, materials, and combinations which will provide
a minimum cost and a highly reliable hypodermic syringe needle assembly,
the scope of which is indicated by the appended claims.
DESCRIPTION OF DRAWINGS
FIG. 1 is a longitudinal sectional view through the needle cover
before assembly with a needle.
FIG. 2 is a cross section along line 2--2 of FIG. 3.
FIG. 3 is a longitudinal cross section of the needle assembly with
the needle assembled with the cover and the assembly attached to
the syringe in the deactivated position.
FIG. 4 is a longitudinal section through the assembly with the
needle assembled with the cover and the needle assembly in activated
position with the syringe.
DESCRIPTION OF PREFERRED EMBODIMENT
Referring to FIG. 3 the needle assembly comprises a needle 310
a needle holder 311 and a needle cover 301. The outer portion 302
of needle cover 301 covers the outer portion of the needle 310
a middle portion 303 of needle cover 301 covers the needle holder
311 which is fastened to the middle portion of needle 310 and an
inner portion 304 of needle cover 301 covers the inner portion of
needle 310. The inner portion 304 is provided with an assembly flange
305 which attaches to the syringe body 100 and is secured by a groove
101 acting with assembly flange 305 of the needle assembly. The
portions 302 303 304 and 305 as shown in FIG. 1 are fabricated
in one piece such as by plastic molding. The portions are joined
together by means of connecting webs 102 and 103. Since connecting
web 102 extends completely around inner portion 304 and middle portion
303 and connecting web 103 extends completely around middle portion
303 and outer portion 302 when connecting flange 305 is secured
to the syringe body 100 the needle cover 301 provides complete
sterility for needle 310 FIG. 3 since it is both an air seal and
a water seal. In certain applications in which a water seal is not
required and it is desirable to reduce the breaking forces of the
connecting webs 102 and 103 the connecting webs 102 and 103 can
be segmented in such a manner that only portions of the webs or
spokes hold the portions 302 303 and 304 of the needle cover 301
together. Even with the connecting webs 102 and 103 segmented, sterility
for the needle is maintained as will be described later. The needle
310 is held in a needle holder 311 which is crimped to the needle
310. The needle holder 311 provides proper holding force to retain
the needle properly in the needle mounting structure. As shown in
FIG. 3 the needle holder 311 has a hub 312 extending towards the
outer portion of needle 310 and an expansion ring 313 extending
towards the inner portion of needle 310. As shown in FIG. 1 fingers
104 are attached to the middle portion 303 of the needle cover 301.
When the needle holder 311 is press fitted into the middle portion
303 of the needle cover 301 the expansion ring 313 engages the
fingers 104 in such a manner that they deflect the fingers 104 in
an outward direction so that their outer tips 105 engage surface
306 of inner portion 304 of needle cover 301. Surface 306 is provided
with a step 106 which acts with outer tips 105 of fingers 104 to
prevent outward movement of middle portion 303. Inserting the needle
holder 311 into its correct assembled location deflects fingers
104 such that they are acting as a cantilever spring restrained
by surface 306. Surface 306 is provided at its inner most end with
another step 107 into which outer tips 105 engage as will be described
later.
Since most disposable prefilled syringes require a plunger rod
to move the plunger which transfers the fluid from the syringe chamber
through the needle this disclosure shows the convenient method of
assembling the plunger rod 320 over the needle assembly for storage
and shipment. This overlapping of parts reduces the size of the
packaging required during storage and shipment and also functions
to maintain the sterility of the assembly if the connecting web
102 is segmented. Outer hub 312 of the needle holder 311 engages
an inner recess 110 of outer portion 302 of needle cover 301 to
form a path with two right angle bends between the needle 310 and
connecting web 103. This non-direct line between the outer end of
needle 310 and the outside of the unit as well as the covering provided
by the plunger rod 320 to seal any openings in connecting webs 102
and 103 provide for sterility against airborne contaminants. As
shown in FIG. 3 the plunger rod 320 is held onto the needle cover
301 by means of two projections 108 engaging an inside ring 120
on plunger rod 320. This interference between the projections 108
and the inside ring 120 prevent the plunger rod 320 from accidentally
falling off the needle cover 301.
In order to activate the syringe, that is, moving the inner portion
of the needle 310 into and through the closing diaphragm 401 of
the syringe, a force must be applied to break the connecting web
102. This breaking force can be applied to the projections 321 of
the plunger rod 320 in the direction towards the syringe body. Pressure
on the projections 321 applies pressure to a shoulder 322 which
in turn applies the same pressure to a mating shoulder 109 on needle
cover 301. Since the connecting web 102 is designed so that the
linear pressure on shoulder 109 breaks the connecting web 102 further
pressure on the projections 321 will move the needle cover 301
the needle 310 towards the closing diaphragm 401 and continue until
the needle 310 pierces the closing diaphragm 401. Guiding of the
needle during movement of the needle 310 from the deactivated position
to the activated position is done by surfaces that formed the connecting
web 102 and the outer tips 105 of fingers 104 riding on surface
306. When the needle has completely pierced the closing diaphragm
401 the outer tips 105 latch into step 107 due to the spring force
that was built into the fingers 104 when the needle holder 311 was
inserted into the needle cover 301. When the outer tips 105 engage
the step 107 the needle assembly cannot be withdrawn or retracted
without distruction of parts. The activated needle assembly is shown
in FIG. 4. After activation the inner end of needle 310 is inside
the closing diaphragm 401 and therefore the needle remains sterile
even if plunger rod 320 is removed from a needle cover 301.
In operation of syringes of this type, the syringe is first activated
as just described. After activation the plunger rod is removed from
the needle cover assembly and is assembled into the plunger at the
other end of the syringe as previously described. Since the syringe
may not be used at this time it is important that the injecting
end of the needle remains sterile and protected. As a result, after
activation and removal of the plunger rod the needle must still
be protected by the outer portion 302. As was previously described,
the outer portion 302 is held to the middle portion 303 by means
of connecting web 103. Connecting web 103 as previously described,
can be a complete enclosure around the body of the needle cover
301 or can be segments. In either case, airborne sterility is maintained,
as previously described, by the mating of the outer hub 312 with
inner recess 110. When the nurse or doctor wishes to utilize the
syringe, the outer portion 302 of needle cover 301 is broken away
from the needle assembly. This action can be done by pulling the
outer cover 302 off thus breaking the web, or by turning the outer
cover 302 thus breaking the web. The needle assembly is prevented
from coming from the syringe in these motions due to the engagement
of the outer tips 105 into step 107. In certain applications, as
mentioned above, it may be desirable to break the connecting webs
102 and 103 by rotating the parts relative to one another. As a
result, the needle assemblies can be made with projections, with
flats, or other special configurations on the outside surface which
would aid in hand rotation of the parts.
As a result of the above description when read in light of the
accompanying drawings, it has been shown that a needle assembly
can be manufactured with a minimum number of parts and that the
needle cover is a single part. Even with these minimum number of
parts the syringe can maintain its sterility during storage and/or
shipment. It also has been shown that the syringe with the described
needle assembly can maintain sterility even if submersed in a fluid.
The above description describes a system in which the needle cover
is one molded part and is assembled to a cannula or needle by means
of a needle holding member. Although the above description and drawings
show a preferred embodiment of the invention, this invention should
not be limited to the description and drawing but by the appended
claims. |