Safety syringe abstract
A syringe is disclosed which includes a needle body having a proximal
end and a distal end, a needle attached to the distal end of the
needle body, a plunger for drawing fluid into the needle body through
the needle, and a protective sheath configured and dimensioned to
be positioned about the needle body and movable between a first
distal position whereby the needle is shielded by the sheath and
a proximal position whereby the needle is exposed. A system of slots
and pegs is provided to releasably retain the protective sheath
in the first distal position and to releasably retain the protective
sheath in the proximal position. Also a system to retain and lock
the protective sheath in a second distal position after use whereby
the needle is protected by the sheath. A method of using the safety
syringe to protect the needle from inadvertent contact with the
user or any person in the area of use is also disclosed.
Safety syringe claims
What is claimed is:
1. A safety syringe which comprises:
a) a needle body having a proximal end and a distal end and defining
a fluid chamber;
b) a needle attached to said distal end of said body and communicating
with said fluid chamber;
c) means for manually drawing fluid into said chamber and expelling
fluids out of said chamber through said needle;
d) a safety sheath positioned about said needle body, said sheath
having a fixed angular orientation with respect to said needle body
about a longitudinal axis extending therethrough, and movable between
a first distal position whereby said needle is shielded by said
sheath, a proximal position whereby said needle is exposed, and
a second distal position whereby said needle is protected by said
sheath;
e) means movable toward and away from said safety sheath to releasably
retain said sheath in said first distal position and said proximal
position and including means for facilitating reception of a user's
finger; and
f) means to lockingly retain said safety sheath in said second
distal position, said second distal position being distal of said
first distal position whereby said needle is protected from unwanted
contact after use.
2. A safety syringe according to claim 1 wherein said needle body
is an elongated member defining said inner fluid chamber.
3. A safety syringe according to claim 2 wherein said needle body
is an elongated cylindrical member and said inner fluid chamber
is cylindrically shaped, and a plunger assembly is positioned within
said inner fluid chamber for drawing or expelling fluids with respect
thereto.
4. A safety syringe according to claim 3 wherein said needle body
includes a plurality of slots dimensioned, positioned and configured
for reception of a plurality of corresponding locking pegs which
extend inwardly of said safety sheath to retain said sheath in at
least one of a plurality of selective positions relative to said
needle body.
5. A safety syringe according to claim 4 wherein at least two of
said plurality of slots in said needle body are positioned in the
proximal portion of said needle body and are configured for reception
of at least two of said plurality of locking pegs on said safety
sheath to retain said safety sheath in said proximal position relative
to said needle body whereby said needle is exposed for use.
6. A safety syringe according to claim 5 wherein at least two of
said plurality of slots are positioned in the distal portion of
said needle body and are configured for reception of at least two
of said plurality of locking pegs on said safety sheath to retain
said safety sheath in said first distal position relative to said
needle body, whereby said needle is covered.
7. A safety syringe according to claim 6 wherein at least two of
said plurality of slots in said needle body are positioned distally
of said first mentioned distal slots for reception of at least two
of said plurality of locking pegs on said safety sheath, said pegs
being dimensioned, positioned and configured to lockingly retain
said safety sheath in said second distal position relative to said
needle body.
8. A safety syringe according to claim 7 wherein said slots to
retain said safety sheath in said second distal position are configured
to retain said correspondingly configured and positioned locking
pegs on said safety sheath in a manner whereby said locking pegs
are not removable from said slots by normal action of the user.
9. A safety syringe according to claim 8 wherein said locking slots
in said needle body are each positioned adjacent and distal of a
ramped surface thereon, said ramped surface being adapted and configured
for slidable reception of said locking pegs on said safety sheath
to facilitate slidable entry of said locking pegs into said locking
slots positioned distally of said ramped surfaces.
10. A safety syringe according to claim 9 wherein said locking
pegs on said safety sheath include a ramped surface substantially
parallel to said ramped surface on said needle body to facilitate
slidable engaged reception of said locking pegs into said locking
slots.
11. A safety syringe according to claim 10 wherein said locking
pegs are attached to said safety sheath in a manner to be resiliently
movable in a direction away from said needle body such that said
locking pegs are resiliently biased in a direction toward said slots
on said needle body to lock said safety sheath in said second distal
position.
12. A safety syringe according to claim 11 wherein said ramped
surface on said needle body extends in a direction radially outwardly
of said needle body from the proximal end to the distal end of said
ramped surface.
13. A safety syringe according to claim 12 wherein said ramped
surface on each of said locking pegs attached to said safety sheath
extends in a direction radially outwardly toward the inner surface
of said safety sheath in a direction from the proximal end to the
distal end of said ramped surface.
14. A safety syringe according to claim 13 wherein said safety
sheath is constructed of a resilient material and said locking pegs
are attached to strips formed integrally with said safety sheath
and are adapted to be resiliently biased inwardly toward said safety
sheath.
15. A safety syringe according to claim 14 wherein said resilient
material is plastic.
16. A safety syringe according to claim 15 wherein said plastic
is transparent or translucent.
17. A safety syringe according to claim 16 wherein said plastic
is at least one of polyethylene polypropylene and polycarbonate.
18. A safety syringe according to claim 17 wherein said safety
sheath includes at least two elongated strips formed therefrom and
attached at their distal ends to said safety sheath intermediate
the length thereof and the proximal ends of said strips resiliently
biased inwardly toward said safety sheath.
19. A safety syringe according to claim 18 wherein each of said
elongated strips have a continuous loop structure positioned at
the proximal end thereof, each loop dimensioned for reception of
one of the user's finger.
20. A safety syringe according to claim 19 wherein each finger
loop is circular.
21. A safety syringe according to claim 20 wherein a finger loop
is connected to said plunger assembly for movement of said plunger
assembly in distal and proximal directions.
22. A safety syringe according to claim 21 wherein said elongated
strips and said finger loops are integrally molded with said safety
sheath in a manner which facilitates outward movement of said strips
with respect to said safety sheath while the distal end of said
strips are integrally attached to said safety sheath.
23. A safety syringe according to claim 1 wherein said needle body
includes at least one guide track extending lengthwise thereof and
dimensioned for slidable reception of at least one correspondingly
positioned and dimensioned guide peg extending inwardly of the inner
surface of said safety sheath to retain the relative angular orientation
between said safety sheath and said needle body.
24. A safety syringe according to claim 1 wherein said needle body
includes at least four guide tracks extending lengthwise thereof
and said safety sheath includes at least four correspondingly positioned
and dimensioned guide pegs, said tracks and said pegs being distributed
approximately equally about said needle body to maintain rigidity
and minimize lateral play within said safety sheath and said needle
body.
25. A safety syringe according to claim 1 wherein said needle body
comprises at least two guide tracks extending lengthwise thereof
and dimensioned for slidable reception of at least two correspondingly
positioned and dimensioned guide pegs extending inwardly of the
inner surface of said safety sheath to retain the relative angular
orientation between said safety sheath and said needle body.
26. A safety syringe according to claim 1 wherein said needle body
comprises at least two guide tracks extending lengthwise thereof
and dimensioned for slidable reception of at least four correspondingly
positioned and dimensioned guide pegs extending inwardly of the
inner surface of said safety sheath to retain the relative angular
orientation between said safety sheath and said needle body.
27. A safety syringe according to claim 1 wherein said needle body
comprises at least three guide tracks extending lengthwise thereof
and dimensioned for slidable reception of at least three correspondingly
positioned and dimensioned guide pegs extending inwardly of the
inner surface of said safety sheath to retain the relative angular
orientation between said safety sheath and said needle body.
28. In combination with a syringe having a needle body having a
generally cylindrical hollow needle attached to a distal end thereof
and having means for drawing fluid into or expelling fluid out of
a chamber defined internally of said needle body, the improvement
in combination therewith which comprises a safety sheath positioned
about said needle body, said sheath having a fixed angular orientation
with respect to said needle body about a longitudinal axis extending
therethrough, and adapted for slidable movement between a first
distal position, a second distal position and a proximal position
relative to said needle body, means movable toward and away from
said sheath and releasably engagable with said needle body to releasably
retain said safety sheath in said first distal position whereby
said needle is covered by said safety sheath and said proximal position
whereby said needle is exposed for use, and including means for
facilitating reception of a user's finger at least one guide track
extending lengthwise of said needle body and at least one correspondingly
positioned and dimensioned guide peg extending inwardly of said
sheath for cooperating with said guide tracks to maintain the angular
orientation of said sheath with respect to said needle body while
permitting relative distal and proximal movement therebetween, and
means to lockingly retain said safety sheath in said second distal
position whereby said needle is protected thereby, said last mentioned
retaining means being substantially locked from disengagement by
the user.
29. A syringe according to claim 28 wherein said needle body comprises
at least two of said guide tracks and said safety sheath comprises
at least two of said correspondingly positioned and dimensioned
guide pegs.
30. A syringe which comprises:
a) a needle body having a proximal end and a distal end;
b) a needle attached to said distal end of said needle body;
c) means for drawing fluid into said needle body and expelling
fluid out of said needle body through said needle;
d) a protective sheath configured and dimensioned to be positioned
about said needle body, said sheath having a fixed angular orientation
with respect to said needle body about a longitudinal axis extending
therethrough, and movable between a first distal position whereby
said needle is shielded by said sheath, a proximal position whereby
said needle is exposed, and a second distal position distal of said
first distal position whereby said needle is protected from unwanted
contact after use;
e) means movable toward and away from said protective sheath to
releasably retain said protective sheath in said first distal position
and said proximal position and including means for facilitating
reception of a user's finger; and
f) means to lockingly retain said protective sheath in said second
distal position after use whereby said needle is protected by said
sheath.
31. A syringe which comprises:
a) a cylindrical needle body having a proximal end and a distal
end, said needle body including a plurality of slots;
b) a needle attached to said distal end of said needle body;
c) a plunger assembly for drawing fluid into said needle body and
expelling fluid out of said needle body; and
d) a protective sheath configured and dimensioned to be positioned
about said needle body and movable between a first distal position
wherein said needle is shielded by said sheath and a proximal position
wherein said needle is exposed, said sheath including a plurality
of resilient strips formed therefrom, at least two of said strips
including at least one peg extending inwardly therefrom to cooperate
with said plurality of slots of said needle body to retain said
sheath in a plurality of axial positions relative to said needle
body, said strips being movable toward and away from said sheath
to thereby allow selective contact between said pegs on said strips
and said slots of said needle body, at least two of said strips
having a continuous loop positioned at a proximal end portion thereof
for reception of the user's finger, whereby said protective sheath
may be withdrawn from said first distal position to said proximal
position to permit use of said needle, and thereafter advanced to
a second distal position wherein said protective sheath is locked
in a needle protective position by reception of at least two of
said locking pegs with at least two of said slots.
32. A method of using a syringe having a hollow medical needle
whereby the needle is protected from user contact before and after
use, comprising:
a) providing a needle body having a proximal end and a distal end
and having said needle attached thereto, a safety sheath having
a fixed angular orientation with respect to said needle body about
a longitudinal axis extending therethrough, means movable toward
and away from said sheath and releasably engageable with said needle
body for releasably retaining said sheath in a first distal position
whereby said needle is shielded prior to use and a proximal position
whereby said needle is exposed for use, and including means for
facilitating reception of a user's finger and means to lockingly
retain said sheath in a second distal position distal of said first
distal position whereby said needle is shielded by said sheath;
b) moving said movable means away from said safety sheath to thereby
release said safety sheath from said first distal position and moving
said safety sheath to said proximal position whereby said needle
is exposed for use; and
c) advancing said safety sheath to said second distal position
whereby said needle is protected by said safety sheath and contact
therewith by the user is prevented.
33. A method of using a syringe according to claim 32 whereby said
syringe includes an elongated needle body and said needle is attached
to the distal end thereof, said needle communicating with an inner
chamber defined by said needle body for reception of fluids through
said needle and said sheath is automatically and simultaneously
locked in said second distal position when advanced thereby by the
user.
34. A method of using a syringe according to claim 29 wherein said
needle body includes a plunger assembly therein for drawing fluids
into and discharging fluids out of said chamber.
Safety syringe description
CROSS REFERENCE TO RELATED DOCUMENTS
The present invention relates to a safety syringe as disclosed
in Disclosure Document No. 245403 filed Feb. 12 1990.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a syringe. More particularly the
syringe includes a safety sheath selectively movable by one hand
to positions whereby the needle may be exposed or covered, one of
the needle covering positions being automatically locked when the
sheath is moved thereto.
2. Background of the Prior Art
Protection for medical personnel from inadvertent contact with
contaminated syringe needles has become an increasing concern particularly
because of the severity of certain infectious diseases which have
developed. For example, the AIDS virus has been shown to be spread
to persons who come into contact with a contaminated needle after
the needle was used for a patient carrying the virus.
Numerous attempts have been made to protect medical personnel,
patients and anyone in the area when syringes are used by providing
various shielding devices for the needles. For example, U.S. Pat.
No. 4969877 relates to a syringe which includes an outer casing
into which the needle may be retracted after use. U.S. Pat. No.
4973316 relates to a one handed retractable sheath safety syringe.
A number of other attempts at providing protection for safety syringe
needles have been made.
None of the safety devices developed to date provide relatively
simple and quick one hand application whereby the user may simply
slide a protective device into several positions with one position
being a locked position which is irreversible by normal action of
the user. Further, there remains a need for such safety syringes
which would be usable as an injecting syringe or as an aspirating
syringe, all with one hand operation, while being simply automatically
convertible to a configuration whereby the needle is covered and
protected while preventing inadvertent re-exposure of the needle.
The present invention provides such a safety syringe.
SUMMARY OF THE INVENTION
A syringe which comprises a needle body having a proximal end and
a distal end, a needle attached to the distal end of the needle
body, means for drawing fluid into the needle body through the needle,
and a protective sheath configured and dimensioned to be positioned
about the needle body and movable between a first distal position
whereby the needle is shielded by the sheath and a proximal position
whereby the needle is exposed. The syringe includes means to releasably
retain the protective sheath in the first distal position, means
to releasably retain the protective sheath in the proximal position,
and means to retain the protective sheath in a second distal position
after use whereby the needle is protected by the sheath. Preferably,
the sheath automatically becomes locked in the second distal position
when it is moved to this position.
In a preferred embodiment the needle body has a proximal end and
a distal end and defines a fluid chamber. The needle is attached
to the distal end of the body and communicates with the fluid chamber.
Means is provided for manually drawing fluid into the chamber through
the needle and the protective sheath is positioned about the needle
body and movable between a first distal position whereby the needle
is shielded by the sheath and a proximal position whereby the needle
is exposed. Means to releasably retain the sheath in the first distal
position is provided and means to releasably retain the protective
sheath in the proximal position is provided. The syringe includes
means to lockingly retain the protective sheath in a second distal
position, the second distal position being distal of the first distal
position whereby the needle is protected from unwanted contact after
use.
Preferably the needle body is an elongated cylindrical member defining
the inner fluid chamber and the fluid chamber is cylindrically shaped.
A plunger assembly is positioned within the inner fluid chamber
for drawing or expelling fluids with respect thereto. The needle
body includes a plurality of slots dimensioned, positioned and configured
for reception of correspondingly shaped pegs which extend inwardly
of the protective sheath to retain the sheath in at least one of
a plurality of selective positions relative to the needle body.
At least two of the slots in the needle body are positioned in
the proximal portion of the needle body and are configured for reception
of at least two correspondingly dimensioned pegs on the safety sheath
to retain the safety sheath in the proximal position relative to
the needle body whereby the needle is exposed for use. At least
two of the slots are positioned in the distal portion of the needle
body and are configured for reception of at least two correspondingly
dimensioned pegs on the safety sheath to retain the safety sheath
in the first distal position relative to the needle body, whereby
the needle is covered. Further, at least two of the slots in the
needle body are positioned distally of the first mentioned distal
slots for reception of at least two of the pegs on the safety sheath,
the pegs being dimensioned, positioned and configured to lockingly
retain the safety sheath in the second distal position relative
to the needle body.
The slots which retain the safety sheath in the second distal position
are configured to retain the correspondingly configured and positioned
locking pegs on the safety sheath in a manner whereby the locking
pegs are not removable from the slots by normal action of the user.
Further, the locking slots in the needle body are each positioned
adjacent and distal of a ramped surface thereon, the ramped surface
being adapted and configured for slidable reception of the locking
pegs on the safety sheath to facilitate slidable entry of the locking
pegs into the locking slots positioned distally of the ramped surfaces.
The locking pegs on the safety sheath include a ramped surface substantially
parallel to the ramped surface on the needle body to facilitate
slidable engaged reception of the locking pegs into the locking
slots.
In the safety syringe according to the invention, the locking pegs
are attached to the safety sheath in a manner to be resiliently
movable in a direction away from the needle body such that the pegs
are resiliently biased in a direction toward the locking slots on
the needle body to lock the position of the safety sheath in the
second distal position. The ramped surface on the needle body extends
in a direction radially outwardly of the needle body from the proximal
end to the distal end of the ramped surface. The ramped surface
on the peg attached to the safety sheath extends in a direction
radially outward toward the inner surface of the safety sheath in
a direction from the proximal end to the distal end of the ramped
surface Further, the safety sheath is constructed of a resilient
plastic material and the locking pegs are attached to strips formed
integrally with the safety sheath and are adapted to be resiliently
biased inwardly toward the safety sheath. The plastic material is
transparent or translucent but may be opaque if desired. Such plastics
as polyethylene polypropylene and polycarbonate are contemplated,
but other suitable materials may be used.
The safety sheath includes two elongated strips attached to the
safety sheath at their distal ends and resiliently biased inwardly
toward the safety sheath. Also two similar locking strips are attached
at their proximal ends and include the locking pegs.
Each elongated strip has an endless circular loop positioned at
the proximal end, each loop being dimensioned for reception of one
of the user's fingers. A plunger assembly is positioned within the
needle body and adapted for drawing fluids therein through the needle
by vacuum or out of the needle body by pressure. A finger loop is
connected to the plunger assembly for movement of the plunger assembly
in distal and proximal directions. The needle body includes at least
one guide track extending along the length thereof and dimensioned
for slidable reception of a correspondingly dimensioned peg extending
inwardly of the inner surface of the safety sheath to retain the
relative angular orientation between the safety sheath and the needle
body. Preferably, at least four of the guide tracks are provided
on the safety sheath and at least four of the correspondingly positioned
and dimensioned pegs are provided. The tracks and the pegs are distributed
approximately equally about the needle body to maintain rigidity
and minimize lateral play within the safety sheath and the needle
body. The elongated strips and the finger loops are integrally molded
with the safety sheath in a manner which facilitates outward movement
of the strips with respect to the safety sheath while the distal
end of the strips are integrally attached to the safety sheath.
The proximal ends of the locking strips are integrally molded with
the safety sheath.
A method is disclosed for using a syringe having a hollow medical
needle whereby the needle is protected from contact therewith before
and after use, comprising providing a safety sheath in a first distal
position whereby the needle is shielded prior to use, releasing
the safety sheath and moving same to a proximal position whereby
the needle is exposed for use, and advancing the safety sheath to
a second distal position whereby the needle is protected by the
safety sheath, the safety sheath having means to be locked into
the second distal position whereby movement of the safety sheath
to a position proximal thereof by the user is prevented.
According to the method the syringe includes an elongated needle
body and the needle is attached to the distal end thereof, the needle
communicating with an inner chamber defined by the needle body for
reception of fluids through the needle and the sheath is automatically
and simultaneously locked in the second distal position when advanced
thereby by the user. The needle body includes a plunger assembly
therein for drawing fluids into and discharging fluids out of the
chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are described hereinbelow
with reference to the drawings wherein:
FIG. 1 is a side view of the safety syringe constructed according
to the present invention with the safety sheath in the distal position
protecting the needle from unintended contact;
FIG. 2 is a top view of the safety syringe shown in FIG. 1;
FIG. 3 is a side view of the syringe shown in FIG. 1 with the safety
sheath released and partially withdrawn to expose the needle;
FIG. 4 is a top view of the syringe shown in FIG. 3;
FIG. 5 is a side view of the safety syringe shown in FIG. 3 with
the safety sheath in position in the fully withdrawn position to
permit the syringe to be used normally;
FIG. 6 is top view of the safety syringe shown in FIG. 5;
FIG. 7 is a perspective view with parts removed, illustrating schematically,
one side of the body of the syringe constructed according to the
present invention and the locking system for the safety syringe;
FIG. 8 is a greatly enlarged cross-sectional view illustrating
the sheath safety locking mechanism as the safety sheath is being
moved distally after using the syringe;
FIG. 9 is a greatly enlarged cross-sectional view of the safety
locking mechanism shown in FIG. 8 just prior to locking the safety
sheath in the protective position over the needle;
FIG. 10 is a greatly enlarged cross-sectional view of the safety
locking mechanism shown in FIGS. 8 and 9 when the safety sheath
has been moved distally to the needle protective distalmost position
preventing further needle use;
FIG. 11 is a top view of the needle body with major portions removed,
illustrating the relative positions of the slots in the needle body
on one side which are associated with the safety locking system;
FIG. 12 is a side elevational view thereof, illustrating the safety
locking system according to the invention with the relative positions
between the safety sheath and the needle body shown in the initial
position corresponding to FIG. 1;
FIG. 13 is a side cross-sectional view thereof, illustrating the
relative positions of the safety sheath and needle body after the
safety sheath has been partially withdrawn;
FIG. 14 is a side cross-sectional view thereof, illustrating the
relative positions of the safety sheath and needle body in position
for use of the syringe either as an injecting or a fluid aspirating
syringe;
FIG. 15 is a side cross-sectional view thereof illustrating the
relative positions of the safety sheath and needle body shown in
FIG. 14 after use, with the safety sheath pushed distally to a position
just prior to engagement of the safety locking system; and
FIG. 16 is a side cross-sectional view thereof illustrating the
needle body and the safety sheath with the safety sheath just distally
of the position shown in FIGS. 1 and 2.
FIG. 17 is a proximal end view of the safety syringe shown in FIG.
5 with the rear wall and thumb ring removed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the description which follows "distal" means away
from the user and "proximal" means toward the user.
Referring initially to FIG. 1 the safety syringe 10 constructed
according to the present invention is shown. The syringe may be
of the aspirating type or the injecting type. In the former, fluid
is drawn from the body. In the latter, medication or other fluid
is injected into the body by the needle. In either case, it is important
to protect the needle after it has come in contact with the body
fluids of the person in order to prevent inadvertent contact thereafter
with a person other than the patient.
The safety syringe 10 includes a needle body 12 having a needle
14 at one end communicating with a chamber 16 defined internally
of the needle body and shown in dotted lines. The needle is a medical
or surgical type having a hollow cylindrical cross section for drawing
and expelling liquids with respect to needle body 12. Finger loop
18 is attached to the needle body at a location just proximal of
rear wall 20. A plunger 19 is shown schematically in dotted lines
in FIGS. 1 and 4 and is connected to finger loop 18 by elongated
member 21 also shown schematically.
As shown in FIG. 1 safety sheath 22 includes two finger loops
24 26 attached to the sheath via relatively thin strips which are
preferably formed of resilient material integrally with sheath 22
and which bias the loops inwardly toward the body to the position
shown in FIG. 1. Preferably the safety sheath 22 is constructed
of a transparent or translucent resilient plastic material and formed
as a cylindrical tubular member having resilient strips 28 30 which
are separable from the body of the safety sheath and are attached
at the distalmost portion shown at 32. Although the strips are integrally
molded, i.e., monolithic with the safety sheath, they are actually
separated from the main sheath by molded "cuts" shown
at 30a in FIG. 2 which define the strips and permit the strips
to be moved manually toward and away from the sheath. Further, as
seen in FIGS. 1 and 2 the safety sheath is generally cylindrical
and has portions of the cylindrical wall eliminated as shown at
22a to permit viewing of the transparent liquid measure 16 of the
needle body. Such plastic materials as polyethylene, polypropylene,
or polycarbonates such as LEXAN brand material marketed by General
Electric Company, Pittsfield, Mass., are contemplated. As noted,
preferably, the sheath and the body are integrally molded as shown
from such plastic materials.
The sheath 22 is dimensioned and configured to slide between proximal
and distal positions relative to body 16. Four tracks in the form
of elongated slots 17 are formed in body 12 and four corresponding
pegs 15 extend inwardly from the inner wall of the sheath 22 and
are slidably positioned within tracks 17 to retain the relative
angular orientation of sheath 22 with respect to body 12. In FIGS.
1 and 2 only two of such tracks 17 are shown. The normal pre-use
condition of the syringe is as shown in FIG. 1.
In FIGS. 3 and 4 the body 12 is shown after the safety sheath 22
has been partially withdrawn proximally by the user by placing the
index and middle finger into the finger loops 26 24 and separating
the loops as shown to release pegs 42 from peg reception notches
36 shown in FIG. 11. During this motion the user's thumb is positioned
within finger loop 18. The safety sheath 22 is withdrawn fully to
the proximalmost position shown in FIGS. 5 and 6 when finger loops
24 26 are permitted to return to their inwardly biased positions.
At this time, pegs 42 enter slots 34 and thereby fix the position
of the safety sheath 22 relative to the body 12 in the needle exposed
condition shown in FIGS. 5 and 6.
The system for releasably retaining the safety sheath 22 in the
pre-use condition and the final safety locking system will now be
described in connection with FIGS. 7 8 and 11-16. In connection
therewith for convenience of illustration in FIGS. 11-16 the locking
system associated with one finger ring 24 will be described. In
FIG. 7 the finger rings 26 and 24 and the remaining portions of
the needle body 12 and sheath 22 have been removed for illustration
purposes. As constructed, the locking system for the other finger
ring 26 is identical but opposite in configuration and position
to the system associated with the finger ring 24.
Body 12 includes a series of slots 34 36 38 40 as shown in FIG.
11. Beneath finger ring 24 is positioned peg 42 adapted to enter
into either of slots 34 36 or 38 to establish the position of the
safety sheath 22 relative to the body 12. Third, or locking peg
44 is positioned on the internal wall of the sheath 22 and is configured
to enter the distal slot 40 of the needle body. Locking peg 44 is
attached to strip 43 which is cut out of the safety sheath 22 such
that the peg 44 is resiliently biased toward the body 12 by the
inward bias of strips 28 30. This bias is due to the natural resilience
of the plastic material forming the sheath 22 from which the sheath
22 and strips 28 30 are integrally molded. Just proximal of the
distal slot 40 is a ramped member 46 for slidable contact by locking
peg 44 and reception of peg 44 into slot 40 to lock and fix the
position of the sheath in the distalmost, or needle protective position.
In operation, the safety syringe functions as follows. The syringe
is delivered to the user in the configuration shown in FIG. 1 with
the safety sheath 22 in the distal position corresponding to peg
44 being positioned as shown in FIG. 12 while peg 42 immediately
beneath ring 24 being positioned within slot 36. Distal or proximal
movement of sheath 22 is thus prevented by the position of peg 42
within slot 36.
To retract the sheath the user positions the thumb within finger
loop 18 and the index and middle fingers respectively in one of
the aspirating loops 24 26 as described previously. Thereafter,
the index finger and middle finger are separated in opposite directions
to release pegs 42 from slots 36 as shown in FIGS. 3 4 and 13.
The finger motion which releases the pegs is opposite the inward
natural resilient force provided by strips 28 30 as shown in FIG.
3 which are formed out of sheath 22 and are resiliently biased
toward the body 12. The configuration of body 12 is shown clearly
in FIG. 7. The side not shown is the same. As will be observed from
the drawings, after the pegs 42 are released the sheath is now free
to travel in a proximal direction to expose the needle.
Upon withdrawing the sheath proximally to the position shown in
FIG. 14 finger loops 24 26 are returned to the normal inward positions
and pegs 42 re-enter the rearwardly positioned slots 34 thereby
fixing the position of sheath 22 with respect to body 12 and exposing
needle 14 for use. At this point, the needle may be inserted into
the patient's body and the thumb ring 18 may be withdrawn to withdraw
the internal plunger assembly 19 of the needle body for normal use
of the syringe as an aspirating device, i.e. to draw fluid from
the body. Alternatively, this motion may be used to draw fluid from
a separate source--such as medication vial--for injection into the
body as shown in FIG. 12. When the syringe is in the normal use
condition with pegs 42 within slots 34 the distal locking pegs
44 are in a position just distal of slot 38 as shown in FIG. 14.
After normal use of the syringe the aspirating finger loops 24
26 are once again separated laterally by the index and middle fingers
to release pegs 42 from the proximal slots 34 freeing the sheath
for distal movement to a distal position covering needle 14 and
corresponding to the position of peg 44 within slot 40 as shown
in FIG. 10. During this movement, peg 44 which is ramped oppositely--
and preferably approximately parallel--to ramp 46 as shown, slides
over ramp surface 47 of ramp 46 and drops into slots 40 under the
natural inward resilient bias provided by the resilient material
of strip 43. Resilient strips 43 are preferably integrally molded
with sheath 22 similarly to strips 28 30. They are essentially
separated from sheath 22 by cuts 43a and in the same manner as strips
28 30 to bias pegs 44 inwardly toward body 12. When the pegs 44
are positioned within slots 40 the proximal pegs 42 will be positioned
within slots 38 the positions of which are just distal of the initial
slots 36. As noted, since the pegs 44 are also positioned within
slots 40 which are located just distally of the initial position
of pegs 44 shown in FIG. 12 the distal position of sheath 22 will
be fixed relative to the body 12.
It will be appreciated from the view shown in FIGS. 10 and 16 of
the pegs 44 within slots 40 that the configuration of the pegs 44
are such that sheath 22 is locked into a distal needle protective
position just slightly distal of the initial position shown in FIG.
1. The resilient action of the material of the strips 43 which cause
pegs 44 to become locked within slots 40 render the sheath 22 immovable
under normal use by the user. Withdrawal of safety sheath 22 from
this locked position is virtually impossible forcing pegs 44 outwardly
of slots 40 against the inward resilient force of strips 43. In
any event, normal user motions will not release the safety sheath.
Thus, the needle is protected by the position of the sheath and
inadvertent contact with the known user or other party is virtually
impossible without forcing the pegs 44 out of slots 40 or physically
destroying the safety sheath 22.
Other variations of the present invention will become evident to
persons skilled in the art within the scope of the claims appended
hereto.
|