U.S. patent number RE33,585 [Application Number 07/332,520] was granted by the patent office on 1991-05-07 for shielded safety syringe.
This patent grant is currently assigned to Habley Medical Technology Corporation. Invention is credited to Clark B. Foster, Terry M. Haber, William H. Smedley.
United States Patent |
RE33,585 |
Haber , et al. |
May 7, 1991 |
Shielded safety syringe
Abstract
A disposable syringe having particular application to vacuum
tube phlebotomy and comprising respective inner and outer needle
carrying and protective cylinders which are coaxially aligned and
axially extensible relative to one another. The inner and outer
cylinders may be locked in a retracted position, whereby a
hypodermic needle is accessible for drawing blood samples from the
patient to an evacuated tube at the inner cylinder. After the last
blood sample has been taken, the inner and outer cylinders may be
locked in an axially extended position, whereby the hypodermic
needle is completely surrounded and shielded by the outer
protective cylinder so as to permit the safe handling of the
syringe while avoiding an accidental needle strike and the possible
spread of a contagious disease.
Inventors: |
Haber; Terry M. (El Toro,
CA), Foster; Clark B. (Laguna Niguel, CA), Smedley;
William H. (Lake Elsinore, CA) |
Assignee: |
Habley Medical Technology
Corporation (Laguna Hills, CA)
|
Family
ID: |
21925150 |
Appl.
No.: |
07/332,520 |
Filed: |
March 31, 1989 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
043042 |
Apr 27, 1987 |
04758231 |
Jul 19, 1988 |
|
|
Current U.S.
Class: |
604/198; 604/263;
600/576 |
Current CPC
Class: |
A61M
5/3243 (20130101); A61B 5/150473 (20130101); A61B
5/150641 (20130101); A61B 5/150496 (20130101); A61B
5/154 (20130101); A61B 5/15003 (20130101); A61B
5/150259 (20130101); A61B 5/150717 (20130101); A61M
5/3271 (20130101); A61B 5/150389 (20130101); A61B
5/150732 (20130101); A61M 5/3272 (20130101); A61B
5/150572 (20130101); A61M 5/3202 (20130101) |
Current International
Class: |
A61B
5/15 (20060101); A61M 5/32 (20060101); A61M
005/32 () |
Field of
Search: |
;604/187,194,195,196,198,263 ;128/763,764,765 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Yasko; John D.
Attorney, Agent or Firm: Fischer; Morland C.
Claims
Having thus set forth the preferred embodiments of this invention,
what is claimed is:
1. A shielded syringe assembly comprising an inner syringe cylinder
having an open proximal end and a substantially closed distal end,
a hypodermic needle supported at and extending outwardly from said
distal end, and an outer protective sleeve having an open proximal
end and an opening in a substantially closed distal end, said outer
sleeve coaxially aligned with and axially advanceable relative to
said inner cylinder from a retracted position, where said needle
projects outwardly through the opening in said sleeve, to an
extended position, where said needle is located within and
completely surrounded by said sleeve;
said inner cylinder having at least one ramp and one stop spaced
axially from one another; and
said outer sleeve having a lip formed at the open proximal end
thereof;
the continuous axial advancement of said outer sleeve from the
retracted position to the extended position causing said lip to
ride up the ramp of said inner cylinder and into the space between
said ramp and said stop to thereby lock said outer sleeve in the
extended position relative to said inner cylinder with said needle
shielded by said outer sleeve.
2. The syringe recited in claim 1, wherein said hypodermic needle
is double ended, such that one end thereof communicates with the
interior of said inner cylinder and the opposite end extends
outwardly from the distal end of said inner cylinder for
penetrating the skin of a patient.
3. The syringe recited in claim 1, wherein said hypodermic needle
is carried by a screw threaded hub, said hub being received within
a screw threaded opening formed in the distal end of said inner
cylinder, such that said needle is coaxially aligned with said
inner cylinder and said outer sleeve.
4. The syringe recited in claim 1, wherein said inner cylinder has
a hollow neck extending outwardly from the distal end thereof for
receiving said hypodermic needle therethrough, and said outer
sleeve has a hollow neck extending outwardly from the distal end
thereof and surrounding the opening formed therein, the neck of
said outer sleeve being sized to receive the neck of said inner
cylinder therewithin when said outer sleeve is in the retracted
position relative to said inner cylinder, such that said inner
cylinder and said outer sleeve may be joined to one another at
their respective necks.
5. The syringe recited in claim 1, wherein said inner cylinder has
a series of said ramps and a series of said stops, said stops being
in spaced, parallel alignment with one another and extending around
the periphery of said inner cylinder at the distal end thereof, and
said ramps also being in spaced, parallel alignment with one
another and extending around the periphery of said inner cylinder,
said series of ramps being spaced proximally from said series of
stops.
6. The syringe recited in claim 5, wherein said series of ramps are
arranged in an interspersed alignment with respect to said series
of stops.
7. The syringe recited in claim 5, wherein each ramp of said series
of ramps and each stop of said series of stops extends axially
along said inner cylinder and comprises an inclined portion, said
series of ramps inclining in a distally oriented direction and said
series of stops inclining in a proximally oriented direction.
8. The syringe recited in claim 5, wherein said inner cylinder has
a hexagonal cross-section comprising a pluraltiy of contiguous
sidewalls, each ramp of said series of ramps projecting outwardly
in a first direction from a respective intersection of a pair of
adjacent sidewalls, and each stop from said series of stops
projecting outwardly in a second direction from said respective
intersection.
9. A shielded safety syringe comprising an inner cylinder having
proximal and distal ends and a hypodermic needle supported by and
extending outwardly from said distal end, said syringe further
comprising:
an outer sleeve having proximal and distal ends and being coaxially
aligned with and movable axially relative to said inner cylinder
from a retracted position, where said needle projects past the
distal end of said outer sleeve, to a distally advanced position,
where said needle is located within and completely surrounded by
said outer sleeve;
first and second locking means being axially spaced from one
another and .[.projecting from.]. .Iadd.extending around the
periphery of .Iaddend.one of said inner cylinder or said outer
sleeve; and
third locking means .Iadd.comprising a lip .Iaddend.projecting from
.Iadd.and extending continuously and uninterruptedly around the
periphery of .Iaddend.the other of said inner cylinder or said
outer sleeve;
the continuous axial movement of said outer sleeve from the
retracted position to the distally advanced position causing
.Iadd.the lip of .Iaddend.said third locking means to be received
in the space between said first and second locking means to thereby
lock said outer sleeve at the distally advanced position with said
needle shielded by said outer sleeve.
10. The syringe recited in claim 9, wherein said first locking
means includes at least one ramp and said second locking means
includes at least one stop.
11. The syringe recited in claim 9, wherein said first locking
means includes a plurality of ramps and said second locking means
includes a plurality of stops, said pluralities of ramps and stops
extending around the periphery of the said one of said inner
cylinder or outer sleeve.
12. The syringe recited in claim 11, wherein said pluralities of
ramps and stops extend around the periphery of said inner cylinder
adjacent the distal end thereof.
13. The syringe recited in claim 11, wherein said plurality of
ramps are arranged in interspersed alignment with respect to said
plurality of stops.
14. The syringe recited in claim 11, wherein said pluralities of
ramps extend around the periphery of said inner cylinder in spaced,
parallel alignment with said plurality of stops. .[.15. The syringe
recited in claim 9, wherein said third locking means includes at
least one lip..]. .[.16. The syringe recited in claim 15, wherein
said lip extends around the periphery of said other of said inner
cylinder or outer sleeve..].
The syringe recited in claim .[.16.]. .Iadd.9.Iaddend., wherein
said lip extends around the periphery of said outer sleeve adjacent
the
proximal end thereof. 18. The syringe recited in claim 9, wherein
said first locking means includes at least one ramp and said second
locking means includes at least one stop, said ramp and said stop
projecting from said inner cylinder adjacent the distal end
thereof; and
said third locking means includes a lip projecting from said outer
sleeve
adjacent the proximal end thereof. 19. The syringe recited in claim
9, wherein said hypodermic needle is double ended, one end of said
needle communicating with the interior of said inner cylinder and
the opposite end of said needle extending outwardly from said
cylinder for penetrating
the skin of a patient. 20. The syringe recited in claim 9, wherein
said needle is carried by a screw threaded hub located at the
distal end of said inner cylinder, said outer sleeve having a screw
threaded neck formed in the distal end thereof, said screw threaded
hub being received within and mated to said screw threaded neck to
releasably retain said outer sleeve in the retracted position with
said needle projecting past the distal end of said outer sleeve.
.[.21. A shielded safety syringe comprising an inner cylinder
having proximal and distal ends and a hypodermic needle supported
by and extending outwardly from said distal end, said syringe
further comprising:
an outer sleeve coaxially aligned with and movable axially relative
to said inner cylinder from a retracted position, where said needle
projects past said outer sleeve, to a distally advanced position,
where said needle is located within and completely surrounded by
said outer sleeve;
first and second locking means being axially spaced from one
another and extending around the periphery of one of said inner
cylinder or said outer sleeve in parallel alignment with each
other; and
third locking means projecting from the other of said inner
cylinder or said outer sleeve;
the continuous axial movement of said outer sleeve from the
retracted position to the distally advanced position causing said
third locking means to be received in the space between said first
and second locking means to thereby lock said outer sleeve at the
distally advanced position
with said needle shielded by said outer sleeve..]. .Iadd.22. A
shielded assembly for successively drawing one or more samples of
body fluid into respective vacuum tubes comprising an inner
cylinder having an open proximal end and a substantially closed
distal end, hypodermic needle means being supported at said distal
end and having first and second needle ends, a first of said needle
ends extending outwardly from said distal end and the second needle
end extending from said distal end inwardly into the interior of
said cylinder for penetration into one or more vacuum tubes, said
first and second needle ends being in fluid communication with each
other, and an outer protective sleeve having an open proximal end
and an opening in a substantially closed distal end, said outer
sleeve coaxially aligned with and axially advanceable relative to
said inner cylinder from a retracted position, where said first
needle end projects outwardly through the opening in said sleeve,
to an extended position, where said first needle end is located
within and completely surrounded by said sleeve;
said inner cylinder having at least one ramp and one stop spaced
axially from one another; and
said outer sleeve having a lip formed at the open proximal end
thereof;
the continuous axial advancement of said outer sleeve from the
retracted position to the extended position causing said lip to
ride up the ramp of said inner cylinder and into the space between
said ramp and said stop to thereby lock said outer sleeve in the
extended position relative to said inner cylinder with said first
needle end shielded by said outer sleeve. .Iaddend. .Iadd.23. A
shielded safety device for successively drawing one or more samples
of body fluid into respective vacuum tubes comprising an inner
cylinder having proximal and distal ends and hypodermic needle
means being supported at said distal end and having first and
second needle ends, a first of said needle ends extending outwardly
from said distal end and the second needle end extending from said
distal end inwardly into the interior of said cylinder for
penetration into one or more vacuum tubes, said first and second
needle ends being in fluid communication with each other, said
device further comprising:
an outer sleeve having proximal and distal ends and being coaxially
aligned with and movable axially relative to said inner cylinder
from a retracted position, where said first needle end projects
past the distal end of said outer sleeve, to a distally advanced
position, where said first needle end is located within and
completely surrounded by said outer sleeve;
first and second locking means being axially spaced from one
another and projecting from one of said inner cylinder or said
outer sleeve; and
third locking means projecting from the other of said inner
cylinder or said outer sleeve;
the continuous axial movement of said outer sleeve from the
retracted position to the distally advanced position causing said
third locking means to be received in the space between said first
and second locking means to thereby lock said outer sleeve at the
distally advanced position with said first needle end shielded by
said outer sleeve. .Iaddend. .Iadd.24. A shielded safety device for
successively drawing one or more samples of body fluid into
respective vacuum tubes comprising an inner cylinder having
proximal and distal ends and hypodermic needle means being
supported at said distal end and having first and second needle
ends, a first of said needle ends extending outwardly from said
distal end and the second needle end extending from said distal end
inwardly into the interior of said cylinder for penetration into
one or more vacuum tubes, said first and second needle ends being
in fluid communication with each other, said device further
comprising:
an outer sleeve coaxially aligned with and movable axially relative
to said inner cylinder from a retracted position, where said first
needle end projects past said outer sleeve, to a distally advanced
position, where said first needle end is located within and
completely surrounded by said outer sleeve;
first and second locking means being axially spaced from one
another and extending around the periphery of one of said inner
cylinder or said outer sleeve in parallel alignment with each
other; and
third locking means projecting from the other of said inner
cylinder or said outer sleeve;
the continuous axial movement of said outer sleeve from the
retracted position to the distally advanced position causing said
third locking means to be received in the space between said first
and second locking means to thereby lock said outer sleeve at the
distally advanced position with said first needle end shielded by
said outer sleeve. .Iaddend.
.Iadd. 5. A shielded safety device for successively drawing one or
more samples of body fluid into respective vacuum tubes comprising
an inner cylinder having proximal and distal ends and hypodermic
needle means being supported at said distal end and having first
and second needle ends, a first of said needle ends extending
outwardly from said distal end and the second needle end extending
from said distal end inwardly into the interior of said cylinder
for penetration into one or more vacuum tubes, said first and
second needle ends being in fluid communication with each other,
said device further comprising:
an outer sleeve having proximal and distal ends and being coaxially
aligned with and movable axially relative to said inner cylinder
from a retracted position, where said first needle end projects
past the distal end of said outer sleeve, to a distally advanced
position, where said first needle end is located within and
completely surrounded by said outer sleeve;
first and second locking means, axially spaced from one another,
located on one of said inner cylinder or said outer sleeve; and
third locking means for cooperative action with said first and
second locking means, located on the other of said inner cylinder
or said outer sleeve;
the continuous axial movement of said outer sleeve from the
retracted position to the distally advanced position causing said
third locking means to be received in the space between said first
and second locking means to thereby lock said outer sleeve at the
distally advanced position with said first needle end shielded by
said outer sleeve. .Iaddend.
.Iadd. 6. A shielded safety device for successively drawing one or
more samples of body fluid into respective vacuum tubes comprising
an inner cylinder having proximal and distal ends and hypodermic
needle means being supported at said distal end and having first
and second needle ends, a first of said needle ends extending
outwardly from said distal end and the second needle end extending
from said distal end inwardly into the interior of said cylinder
for penetration into one or more vacuum tubes, said first and
second needle ends being in fluid communication with each other,
said device further comprising:
an outer sleeve having proximal and distal ends and being coaxially
aligned with and movable axially relative to said inner cylinder
from a retracted position, where said first needle end projects
past the distal end of said outer sleeve, to a distally advanced
position, where said first needle end is located within and
completely surrounded by said outer sleeve;
first locking means, located near the distal end of said inner
cylinder; and
second locking means located near the proximal end of said outer
sleeve;
the continuous axial movement of said outer sleeve from the
retracted position to the distally advanced position causing said
second locking means to cooperatively engage with said first
locking means to thereby lock said outer sleeve at the distally
advanced position with said first needle end shielded by said outer
sleeve.
Description
.Iadd.CROSS REFERENCES TO RELATED PATENTS
This is an application for reissue of U.S. Pat. No. 4,758,231
issued July 19, 1988. .Iaddend.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a disposable syringe having particular
application to vacuum tube phlebotomy and comprising means by which
to shield an associated hypodermic needle to reduce the possibility
of an accidental, and possibly life threatening, needle strike and
the spread of contagious disease.
2. Prior Art
Hypodermic syringes are used for a variety of purposes. By way of a
first example, the syringe may be used for vacuum tube phlebotomy,
where samples of the patient's blood are successively drawn into
respective evacuated tubes by way of a double ended hypodermic
needle. In a second example, the syringe may be used to expulse
fluid medication to a patient by way of a single ended hypodermic
needle and a conventional injection procedure. In either example,
the syringe may be used to treat a patient having a communicable
disease. Prior to disposal of the syringe, the hypodermic needle
thereof is sometimes broken to prevent reuse. Health care workers
are especially susceptible to accidental and potentially infectious
needle strikes due to the careless handling or breaking of the
needle and disposing of the syringe after use. The resulting
mini-accidents caused by an accidental needle strike typically
require a blood test for such diseases as AIDS and hepatitis. The
corresponding cost and inefficiency of testing health care workers
who have received an inadvertent needle strike result in
considerable waste, which may particularly damaging to a health
care facility which is striving for economy.
The following U.S. patents provide examples of syringes having a
hypodermic needle which may be shielded after use to prevent an
accidental needle strike:
U.S. Pat. No. 2,571,653, Oct. 16, 1951;
U.S. Pat. No. 4,356,822, Nov. 2, 1982;
U.S. Pat. No. 4,425,120, Jan. 10, 1984;
U.S. Pat. No. 4,631,057, Dec. 23, 1986.
SUMMARY OF THE INVENTION
In general terms, a disposable syringe is disclosed having
particular application to vacuum tube phlebotomy. The syringe
comprises an inner hypodermic needle carrying syringe and an outer
protective sleeve which are coaxially aligned and axially
extensible relative to one another. That is, the inner cylinder and
outer sleeve may be locked in a retracted position, whereby the
needle is accessible for drawing blood from the patient to an
evacuated phlebotomy tube at the inner cylinder. The inner cylinder
and outer sleeve may also be locked in an axially extended
position, whereby the needle is completely surrounded and shielded
by the outer sleeve to assure safe handling of the syringe while
avoiding an accidental needle strike and the possible spread of a
contagious disease.
In a first embodiment of the invention, a plurality of
longitudinally extending ribs and stops extend around the exterior
of the inner cylinder. The stops are spaced distally from and
interspersed between successive pairs of ribs. A lip is formed
around the proximal end of the outer sleeve. The outer sleeve is
advanced axially relative to the inner cylinder from the retracted
to the extended position, such that the lip of the outer sleeve
rides up and over the fins for receipt within the spaces between
the ribs and stops. A self-locking feature is established when the
lip of the outer cylinder is received between the ribs and stops of
the inner cylinder to prevent the detachment of the outer sleeve
from the inner cylinder and a return of the outer sleeve to the
retracted position.
In a second embodiment, proximal and distal grooves are formed in
and around the periphery of the inner cylinder. Each of a pair of
spring-like locking members includes an oppositely extending arm
and leg which are hingedly connected to a respective pivot at the
proximal end of the outer sleeve. The inner cylinder and outer
sleeve are locked in the retracted position when the legs of the
locking members are received in the proximal groove of the inner
cylinder. Equal and opposite compressive forces are applied to the
arms of the locking members to cause the legs thereof to rotate out
of the proximal groove in the inner cylinder. The outer sleeve is
then axially advanced relative to the inner cylinder from the
retracted to the extended position. A self-locking feature is
established when the normal bias of the spring-like locking members
automatically rotates the respective legs thereof into the distal
groove of the inner cylinder to prevent the detachment of the outer
sleeve from the inner cylinder.
In a third embodiment, a plurality of longitudinally aligned,
spiraling grooves are formed in the inner cylinder. A corresponding
plurality of raised bumps extend radially inward from the outer
sleeve. The inner cylinder and outer sleeve are locked in the
retracted position when the bumps of the outer sleeve are received
at the proximal ends of respective grooves in the inner cylinder.
The inner cylinder is axially advanced relative to the outer sleeve
from the retracted to the extended position, such that the bumps of
the outer sleeve ride through the spiraling grooves of the inner
cylinder to cause the inner cylinder to rotate. A self-locking
feature is established when the bumps of the outer sleeve are
received at the distal ends of the spiraling grooves to prevent the
detachment of the inner cylinder from the outer sleeve.
In a fourth embodiment, a first and second series of relatively
short ramps extend outwardly from the periphery of the inner
cylinder. A first of the series of ramps are spaced proximally from
and interspersed between successive pairs of the second series of
ramps. A rim extends inwardly from the proximal end of the outer
sleeve. The outer sleeve is advanced axially relative to the inner
cylinder from the retracted to the extended position, such that the
rim of the outer sleeve rides up and across the first series of
ramps for receipt within an annular gap established between the
first and second series of ramps. A self-locking feature is
established when the rim of the outer cylinder is received with
said gap to prevent the detachment of the outer sleeve from the
inner cylinder and a return of the outer sleeve to the retracted
position.
In a fifth embodiment, a first and second series of relatively
short ramps project outwardly and in different directions from the
respective intersections of adjacent sidewall which define a
hexagonal inner cylinder. A first of the series of ramps are spaced
proximally from the second series of ramps. A rim extends inwardly
from the proximal end of the outer sleeve. The outer sleeve is
advanced axially relative to the inner cylinder from the retracted
to the extended position, such that the rim of the outer sleeve
rides up and across the first series of ramps for receipt within an
annular gap established between the first and second series of
ramps. A self-locking feature is established when the rim of the
outer cylinder is received within said gap to prevent the
detachment of the outer sleeve from the inner cylinder and a return
of the outer sleeve to the retracted position.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a cross-section of a shielded syringe according to a
first embodiment of the invention having an inner needle carrying
cylinder and an outer protective sleeve locked in a retracted
position relative to one another;
FIG. 2 shows the cross-section of the syringe with the inner
cylinder and outer sleeve axially advanced relative to one another
to the extended position;
FIG. 3 is an isometric illustration of the inner cylinder;
FIG. 4 is a cross-section taken along lines 4--4 of FIG. 3;
FIG. 5 is an isometric illustration of the outer sleeve;
FIG. 6 is an enlarged detail taken from FIG. 2;
FIG. 7 shows a cross-section of a shielded syringe according to a
second embodiment of the invention having an inner needle carrying
cylinder and an outer protective sleeve locked in a retracted
position relative to one another;
FIG. 8 shows a cross-section of the syringe of the second
embodiment with the inner cylinder and outer sleeve axially
advanced relative to one another to the extended position;
FIG. 9 is an isometric illustration of the syringe according to the
second embodiment;
FIG. 10 shows a cross-section of the shielded syringe according to
a third embodiment of the invention having an inner needle carrying
cylinder and an outer protective sleeve locked in a retracted
position relative to one another;
FIG. 11 shows the cross-section of the syringe of the third
embodiment with the inner cylinder and outer sleeve axially
advanced relative to one another to the extended position;
FIG. 12 is an isometric illustration of the inner cylinder of the
syringe of the third embodiment;
FIG. 13 is an isometric illustration of the outer sleeve of the
syringe of the third embodiment;
FIG. 14 shows a cross-section of the shielded syringe according to
a fourth embodiment of the invention having an inner needle
carrying cylinder and an outer protective sleeve locked in a
retracted position relative to one another;
FIG. 15 shows the cross-section of the syringe of the fourth
embodiment with the inner cylinder and outer sleeve axially
advanced relative to one another to the extended position;
FIG. 16 is an isometric illustration of the inner cylinder of the
syringe of the fourth embodiment;
FIG. 17 is a cross-section taken along lines 17--17 of FIG. 16;
FIG. 18 is an isometric illustration of the outer sleeve of the
syringe of the fourth embodiment;
FIG. 19 shows a cross-section of the shielded syringe according to
a fifth embodiment of the invention having an inner needle carrying
cylinder and an outer protective sleeve locked in a retracted
position relative to one another;
FIG. 20 shows the cross-section of the syringe of the fifth
embodiment with the inner cylinder and outer sleeve axially
advanced relative to one another to the extended position;
FIG. 21 is a cross-section taken along lines 21--21 of FIG. 19;
FIG. 22 is an isometric illustration of the inner cylinder of the
syringe of the fifth embodiment; and
FIG. 23 is an isometric illustration of the outer sleeve of the
syringe of the fifth embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A first embodiment of the present invention for a shielded safety
syringe is best described while referring to FIGS. 1-6 the
drawings. Although the syringes illustrated in the drawings hereof
have particular application to vacuum tube phlebotomy (i.e. to
successively drawing one or more samples of blood into respective
vacuum tubes), it is to be expressly understood that the safety
features of this invention are also applicable to a syringe in
which a fluid medication is expulsed into a recipient by means of a
conventional injection procedure. Referring initially to FIG. 1,
there is shown a hypodermic syringe assembly 1 comprising an inner
syringe barrel or cylinder 2 and a cylindrical outer protective
sleeve 4. The inner cylinder 2 and outer sleeve 4 are coaxially
aligned and axially extensible relative to one another, such that
the outer sleeve 4 is adapted for movement between a retracted
position (of FIG. 1) and an axially extended position (of FIG.
2).
Details of the inner syringe cylinder 2 are disclosed while
referring concurrently to FIGS. 1, 3 and 4 of the drawings. Inner
cylinder 2 is preferably formed from a clear plastic material and
has an open proximal end and a wall 5 which defines a substantially
closed distal end. Coextensively formed with and projecting
radially outward from the inner cylinder 2 are a series of
elongated ribs 6. Ribs 6 extend longitudinally and in spaced,
parallel alignment with one another around the exterior of inner
cylinder 2. Each rib 6 includes a proximally oriented ramp portion
7 and a contiguous, distally oriented step portion 8 (best shown in
FIG. 3).
Also coextensively formed with and projecting radially outward from
the inner cylinder 2 are a series of relatively short fins 10. Fins
10 are arranged in spaced, parallel alignment with one another
around the distal end of inner cylinder 2. However, and as is best
shown in FIGS. 3 and 4 of the drawings, the fins 10 are
interspersed between respective pairs of ribs 6. Each fin 10
includes a proximally oriented seat portion 11 and a contiguous,
upwardly extending and distally oriented stop portion 12. As best
shown in FIG. 3, the seat portions 11 of fins 10 lie below and
between the step portions 8 of ribs 6 and the stop portions 12 of
fins 10, for a purpose which will be described in greater detail
hereinafter.
Extending around the open proximal end of inner cylinder 2 is a
flange 14. Projecting outwardly from the distal end wall 5 of inner
cylinder 2 is a neck 16. A screw thread 18 is formed around the
outer periphery of neck 16 to be mated to a corresponding screw
thread formed in the distal end of outer sleeve 4 in order to
interconnect the distal ends of inner cylinder 2 and outer sleeve 4
when the outer sleeve is moved to a retracted position relative to
the inner cylinder and a hypodermic needle 22 is to be made
accessible.
A hole is formed through the neck 16 to define a distal bore which
communicates with the interior of inner cylinder 2. The distal bore
is threaded to receive therewithin a correspondingly threaded end
20 of a hub 24 which carries a conventional double ended needle 22.
The needle carrying hub 24 is removably secured to the distal bore
within neck 16, so that a first end of the needle 22 projects into
the inner cylinder 2 and the opposite end thereof projects
outwardly from the inner cylinder. A soft rubber sheath 26 covers
the end of the needle 22 which projects into the inner cylinder
2.
Details of the outer protective sleeve 4 are now described while
referring concurrently to FIGS. 1 and 6 of the drawings. Outer
sleeve 4 is preferably formed from a resilient plastic material and
has an open proximal end and a flanged wall 32 which defines a
substantially closed distal end. An annular lip 34 extends around
the interior of the open proximal end. A plurality of parallel
aligned, longitudinally extending slots 36 (best shown in FIG. 6)
are formed through outer sleeve 4 from the open proximal end
thereof. The slots 36 maximize the flexibility of the proximal end
of sleeve 4 when such end is snapped into locking engagement with
the inner cylinder 2, in a manner that will soon be disclosed when
referring to FIG. 2.
Projecting outwardly from the distal end wall 32 of outer sleeve 4
is a hollow neck 38. The neck 38 of outer sleeve 4 is sized to
accommodate the neck 16 of inner cylinder 2 therewithin. A screw
thread 40 is formed around the inside periphery of neck 38 to be
mated, as previously indicated, to the corresponding screw thread
18 formed around the neck 16 (best illustrated in FIG. 1) when the
outer sleeve 4 is located in the retracted position relative to
inner cylinder 2 and the distal ends of inner cylinder 2 and outer
sleeve 4 are interconnected at their respective necks 16 and 38 to
permit access to needle 22.
A flared sheath 44 is also disclosed by which to avoid an
accidental needle strike as a consequence of a careless handling of
the syringe 1 with the needle 22 exposed. As is best shown in FIG.
1, the protective sheath 44 has a conical base 46 which is sized to
surround the flanged distal end wall 32 of outer sleeve 4. An
annular receptacle 48 extends from the conical base 46 for
receiving therewithin the neck 38 of outer sleeve 4 in order to
removably attach the sheath 44 to the outer sleeve (i.e. at the
distal end of syringe 1). Coextensively formed with and projecting
from the conical base 46 of sheath 44 is a tapered nose portion 50
in which the needle 22 is to be located. That is to say, the
protective sheath 44 is attached to the distal end of syringe 1
when the outer sleeve 4 is located in the retracted position
relative to inner cylinder 2, such that needle 22 is exposed. By
virtue of the conical base 46 of flared sheath 44, a relatively
large target area and guide are provided by which to reliably and
automatically align the needle 22 for receipt within nose portion
50. In this fashion, the protective sheath 44 and the wide target
area provided by the conical base 46 thereof advantageously enable
the syringe user to accurately and safely locate a hypodermic
needle within a shielded, protective housing while avoiding the
possibility of inadvertently striking himself, a problem which is
inherent with conventional narrow bodied needle caps.
The operation of the syringe 1 is best disclosed when referring
concurrently to FIGS. 1-6 of the drawings. In FIG. 1, the outer
sleeve 4 is located in the retracted position relative to inner
cylinder 2, and the lip 34 of outer sleeve 4 is disposed proximally
of the ribs 6 which extend along inner cylinder 2. The protective
sheath 44 is then removed from the syringe 1 to make the exposed
needle 22 accessible for penetrating the skin of the patient. A
conventional, evacuated phlebotomy tube 52 having a rubber stopper
54 located in the open end thereof is moved through the open
proximal end of inner cylinder 2. The tube 52 is then moved into
contact with the needle 22 at the interior of cylinder 2, such that
the needle penetrates the rubber stopper 54. A blood sample is
automatically suctioned, in a well-known manner, from the patient
to fill the tube 52 via needle 22.
When the last blood sample has been taken, the hypodermic needle 22
is withdrawn from the patient. In order to prevent an accidental
needle strike and the possible spread of contagious disease from a
contaminated needle, the previously connected distal ends of inner
cylinder 2 and outer sleeve 4 are rotated out of engagement with
one another, and the outer sleeve 4 is moved to an axially extended
position relative to inner cylinder 2 (best represented in FIG. 2)
by grasping the inner cylinder 2 at flange 14 and outer cylinder 4
below flanged end wall 32 and sliding the sleeve 4 over the
cylinder 2. More particularly, the displacement of outer cylinder 4
causes a corresponding movement of the annular lip 34 up the ramps
7 and over the steps 8 of ribs 6 (best shown in FIG. 3). Because of
its resilient nature, the lip 34 (which is separated into flexible
lip sections by the longitudinally extending slots 36) will be
rotated outwardly and, thereby, stressed as the lip 34 rides up the
ramp portions 7 or ribs 6. The continued axial advancement of outer
sleeve 4 relative to inner cylinder 2 will cause the lip 34 to be
snapped onto the recessed seats 11 of fins 10 between the stops 12
thereof and the steps 8 of fins 6 (best shown in FIG. 6).
Thus, a positive, self-locking feature is established, because the
lip 34 of outer sleeve 4 is securely and permanently retained below
and between the elevated steps 8 and stops 12, whereby to prevent
both the continued axial advancement of outer sleeve 4 past inner
cylinder 2 as well as a return of the outer sleeve to the retracted
position. What is more, because the seats 11 of fins 10 extend
above the exterior surface of inner cylinder 2, the lip 34 of outer
sleeve 4 will not return to a totally relaxed condition, but will
remain slightly stressed, when received upon the seats 11. The
corresponding compressive force exerted by the flexible lip 34 of
sleeve 4 will prevent the removal of lip 34 from the recessed seats
11 and the detachment of the outer sleeve 4 from the inner cylinder
2.
By virtue of the foregoing, a disposal cartridge (of FIG. 2) is
created having the inner cylinder 2 and outer sleeve 4 locked in an
axially extended position relative to one another with the
hypodermic needle 2 surrounded, completely shielded, and rendered
irretrievable therewithin so as to permit the safe handling of
syringe 1 while avoiding an accidental needle strike. Accordingly,
the specimen tube 52 may be detached from needle 22 and removed
through the open proximal end of inner cylinder 2. However, because
of the permanent nature of the interlocking engagement between
inner cylinder 2 and outer sleeve 4, the syringe 1 cannot be
reused. Moreover, the used syringe is in a condition to permit safe
disposal without requiring the removal or handling of the needle 22
as has heretofor been necessitated as a consequence of many
conventional syringe assemblies.
FIGS. 7-9 of the drawings show a second embodiment of the present
invention for a shielded safety syringe. Like the syringe 1 of
FIGS. 1-6, the syringe 60 of FIGS. 7-9 includes an inner syringe
barrel or cylinder 62 and a cylindrical outer protective sleeve 64.
The proximal ends of cylinder 62 and sleeve 64 are open, and the
distal ends thereof are substantially closed. The inner cylinder 62
and outer sleeve 64 are coaxially aligned and axially extensible
relative to one another, such that outer sleeve 64 is adapted for
movement between a retracted position (of FIG. 7) to an axially
extended position (of FIG. 8).
Also like the syringe 1, syringe 60 includes a screw threaded hub
66 which caries a double ended hypodermic needle 68. The needle
carrying hub 68 is retained within a distal bore formed through a
neck 70 which extends from the distal end wall of inner cylinder
62, whereby one end of needle 68 projects outwardly from the inner
cylinder 62, and the opposite end projects into the cylinder 62 for
communication with an evacuated phlebotomy tube (not shown). The
outer sleeve 64 includes a hollow neck 72 which is sized to
accommodate the neck 70 of inner cylinder 62 so that a tight
friction fit is formed therebetween when the outer sleeve 64 is
located at the retracted position relative to inner cylinder 62.
Accordingly, the distal ends of inner cylinder 62 and outer
cylinder 64 can be temporarily joined at their respective necks 70
and 72 to retain syringe 60 in the retracted position and thereby
provide access to needle 68 (best shown in FIG. 7).
The inner cylinder 62 includes a pair of grooves 74 and 76
extending around the periphery thereof. A first groove 74 is
located below the open proximal end of cylinder 62, and the second
groove 76 is located above the distal end wall thereof.
The outer sleeve 64 includes a pair of oppositely disposed,
spring-like locking members 78 by which to secure the outer
protective sleeve 64 in either of the retracted or axially extended
positions relative to inner cylinder 62. More particularly, each
locking member 78 includes an arm 80 and a leg 82 which are
coextensively formed with and hingedly connected to the outer
sleeve 64 at a joint 84 located at the periphery of the open
proximal end of sleeve 64. As will soon be explained, the arms and
legs 80 and 82 of locking members 78 are adapted to rotate around
their respective joints 84 to form what is known in the art as a
living hinge assembly. To accommodate the rotation of the legs 82
of locking members 78 towards inner cylinder 62, laterally
extending slots (best shown in FIG. 9) are formed through the outer
sleeve 64 below the joints 84.
The operation of the syringe 60 is best described while continuing
to refer to FIGS. 7-9 of the drawings. In FIG. 7, the outer sleeve
64 is located at the retracted position relative to inner cylinder
62 and the legs 82 of locking members 78 are shown in their normal
bias extending through the slots 86 (of FIG. 3) in outer sleeve 64
for receipt by the proximal groove 74 of inner cylinder 62. With
the legs 82 of locking members 78 located in grooves 74, the arm 80
are radially spaced from the outer sleeve 64. The hypodermic needle
68 is now exposed for penetrating the skin of the patient, so that
a phlebotomy tube (not shown) may be infused with a sample of the
patient'blood. After the last blood sample has been taken, and in
order to avoid an accidental needle strike, the inner cylinder 62
is grasped, below major flange 63, and the outer sleeve 4 is moved
to an axially extended position (of FIG. 8) relative to inner
cylinder 62 by sliding the sleeve 64 thereover.
That is to say, equal and opposite compressive forces are applied
(in the direction of the reference arrows of FIG. 7) to the
outwardly extending arms 80 of locking members 78, whereby arms 80
are rotated around pivot 84 against the normal sprig bias thereof
to a new position (shown in phantom) in closer proximity to outer
sleeve 64. The rotation of arms 80 causes a corresponding rotation
of legs 82 in an opposite direction around pivot 84 and out of
proximal groove 74 to a detached position (also shown in phantom)
relative to the inner cylinder 62. Accordingly, outer sleeve 64 is
free to slide over inner cylinder 62 in the direction indicated by
the reference arrow of FIG. 8.
After outer sleeve 64 has been axially advanced, such that the
proximal end thereof is moved adjacent the distal end of inner
cylinder 62, the spring biased legs 82 of locking members 78 are
automatically rotated around hinges 84, through the slots 86, and
snapped into receipt by the distal grooves 76 of inner cylinder 62.
With the legs 82 of locking members 78 received within grooves 76,
a positive, self-locking feature is established, whereby to prevent
both the continued axial advancement and possible detachment of
outer sleeve 64 from inner sleeve 62 as well as an inadvertent
return of the outer sleeve 64 to the retracted position of FIG. 7.
Therefore, a disposal cartridge is created (in FIG. 8) having the
inner cylinder 62 and outer sleeve 64 locked and axially extended
relative to one another with the hypodermic needle 68 completely
surrounded and shielded, so as to permit the safe handling of the
syringe 60 while avoiding an accidental needle strike and the
possible spread of a contagious disease.
FIGS. 10-13 of the drawings show a third embodiment of the present
invention for a shielded safety syringe. Like the syringes of FIGS.
1-9, the syringe 90 of FIGS. 10-13 includes an inner cylinder 92
and an outer protective sleeve 94 which are coaxially aligned and
axially extensible relative to one another between a retracted
position (of FIG. 10) and an axially extended position (of FIG.
11). The inner cylinder 92 has an open proximal end for receiving
an evacuated phlebotomy tube (not shown) and a substantially closed
distal end wall. A screw threaded hub 96, which carries a double
ended needle 98, is retained within a distal bore formed through a
neck 100 which extends from the distal end wall of inner cylinder
92, whereby one end of the needle 98 projects outwardly from the
inner cylinder 92, and the opposite end projects into the cylinder
92 for communication with the phlebotomy tube.
The outer sleeve 94 includes an open proximal end for passing the
inner cylinder 92 therethrough and a substantially closed, flanged
distal end wall 101 having a hollow neck 102 extending outwardly
therefrom. Neck 102 is sized to accommodate the neck 100 of inner
cylinder 92, so that a tight friction fit is formed therebetween
when the outer sleeve 94 is moved to a retracted position relative
to inner cylinder 92. Accordingly, the distal ends of inner
cylinder 92 and outer sleeve 94 can be temporarily joined at their
respective necks 100 and 102 to retain syringe 90 in the retracted
position and thereby permit access to the needle 98 (best shown in
FIG. 10). A plurality (e.g. three) of raised locking bumps 104 are
coextensively formed with and project radially inward from the
outer sleeve 94. The bumps 104 are spaced around the interior of
outer sleeve 94 below the open proximal end thereof. A
corresponding plurality (e.g. three) of parallel aligned,
longitudinally extending slots 106 (best shown in FIG. 13) are
respectively formed through outer sleeve 94 between pairs of bumps
104. The slots maximize the flexibility of outer sleeve 94 for
retaining the locking bumps 104 in engagement with the inner
cylinder 92, as will soon be explained.
As is best shown in FIG. 12, a series (e.g. three) of generally "S"
shaped, longitudinally extending and spiraling grooves 108 are
formed in the exterior of outer sleeve 94. Although an S-shaped
groove is illustrated, it is to be expressly understood that
grooves 108 may have any other suitable shape. The grooves 108 are
spaced from one another around the periphery of outer sleeve 104
and provide guide paths through which the locking bumps 104 of
inner cylinder 92 are adapted to ride when the inner cylinder 92 is
moved axially between the retracted and extended positions relative
to outer sleeve 94.
As is best shown in FIGS. 9 and 10, the open proximal end of inner
cylinder 92 terminates at a flared portion 110. Flared portion 110
includes a slotted opening 112 extending therearound. A lip 114 is
formed at the most distal aspect of flared portion 110. A
cylindrical collar 116 having a pair of oppositely disposed,
outwardly extending finger loops 118 and a coextensively formed,
inwardly extending flange 120 is attached to the flared proximal
portion 110 of inner cylinder 92. In the assembled syringe
relationship shown in FIGS. 9 and 10, the flange 120 of collar 116
is received through the opening 112 in flared portion 110 and
retained behind the lip 114. The lip 114 prevents the withdrawal of
the flange 120 from opening 112 and the removal of collar 116 for
the flared proximal portion 110 of inner cylinder 92. However, the
inner cylinder 92 is free to rotate relative to both outer sleeve
94 and collar 116.
The operation of the syringe 90 is best described while continuing
to refer to FIGS. 10-13. In FIG. 10, the inner cylinder 92 is
located at the retracted position relative to outer sleeve 94 and
the locking bumps 104 of inner cylinder 92 are positioned at the
proximal ends of grooves 108. The hypodermic needle 98 is now
exposed for penetrating the skin of the patient, so that a
phlebotomy tube (not shown) may be infused with a sample of the
patient's blood. After the last blood sample has been taken, and in
order to avoid an accidental needle strike, the outer sleeve 94,
below flanged end wall 101, and the finger loops 118 of the collar
116 are grasped, and the inner cylinder 92 is pulled to the axially
extended position (of FIG. 11) relative to outer sleeve 94, whereby
cylinder 92 is caused to simultaneously slide and rotate through
sleeve 94. That is to say, the bumps 104 of outer sleeve 94 ride
along the spiraling grooves 108 from the proximal to the distal
ends thereof until inner cylinder 92 has been axially advanced,
such that the distal end thereof is moved adjacent the proximal end
of outer sleeve 94. The axial advancement of inner cylinder 92
through outer sleeve 94 and the corresponding travel of locking
bumps 104 through spiraling grooves 108 causes an automatic
rotation of the inner cylinder 92 relative to outer sleeve 94 and
collar 16. The axial and rotational movement of inner cylinder 92,
as the cylinder is moved through outer sleeve 94 to the axially
extended position, is indicated by the pair of reference arrows in
FIG. 11.
When the locking bumps 104 are seated at the distal ends of
spiraling grooves 108, a self-locking feature is established,
whereby to prevent both the continued axial advancement and
possible detachment of inner cylinder 92 from outer sleeve 94 as
well as an inadvertent return of inner cylinder 92 to the retracted
position of FIG. 10. Therefore, a disposal cartridge is created (in
FIG. 11) having the inner cylinder 92 and outer sleeve 94 axially
extended and locked relative to one another with hypodermic needle
98 completely surrounded and shielded, so as to permit the safe
handling of syringe 90 while avoiding an accidental needle strike
and the possible spread of a contagious disease.
FIGS. 14-18 of the drawings show a fourth embodiment of the present
invention for a shielded safety syringe. Like the previously
described syringes of FIGS. 1-13, the syringe 130 of FIGS. 14-18
includes an inner cylinder 132 and an outer protective sleeve 134
which are coaxially aligned and axially extensible relative to one
another from a retracted position (of FIG. 14) to an axially
extended position (of FIG. 15). The inner cylinder 132 has an open,
flanged proximal end for receiving an evacuated phlebotomy tube
(not shown) and a substantially closed distal end wall 135. A screw
threaded hub 136, which carries a double ended needle 138, is
retained within a distal bore formed through a neck 140 which
extends from the distal end wall 135 of inner cylinder 132, whereby
one end of needle 138 projects outwardly from the inner cylinder
132, and the opposite end of needle 138 projects into the cylinder
132 for communication with the phlebotomy tube.
Coextensively formed with and projecting outwardly from the inner
cylinder 132 are first and second series of relatively short ramps
142 and 144 (best shown in FIGS. 16 and 17). A first of a series of
ramps 142 extend in spaced, parallel alignment with one another
around the distal end of inner cylinder 132. The second series of
ramps 144 are spaced proximally from ramps 142 and also extend in
spaced, parallel alignment with one another around inner cylinder
132. However, ramps 142 are interspersed between respective pairs
of ramps 144. Ramps 142 slope upwardly in a proximally oriented
direction, and ramps 144 slope upwardly in a distally oriented
direction, such that the most elevated ends of ramps 142 and 144
oppose one another to establish a narrow, annular gap 146 in the
space therebetween.
The outer sleeve 134 includes an open proximal end for passing the
inner cylinder 132 therethrough and a substantially closed, flanged
distal end wall 148 having a hollow neck 150 extending outwardly
therefrom. The neck 150 of outer sleeve 134 is sized to accommodate
the neck 140 of inner cylinder 132 therewithin. A screw thread is
formed around the inside of the neck 150 of outer sleeve 134 to be
mated to a corresponding screw thread formed around the neck 140 of
inner cylinder 132 (best illustrated in FIG. 14). Accordingly, when
the outer sleeve 134 is located in the retracted position relative
to inner sleeve 132, the inner cylinder and outer sleeve may be
interconnected to one another at their respective necks 140 and 150
to permit access to needle 138. An annular rim 152 (best shown in
FIG. 18) is coextensively formed with and extends around the
interior of outer sleeve 134 at the proximal end thereof for a
purpose which will now be described.
The operation of the syringe 130 is now disclosed while continuing
to refer to FIGS. 14-18 of the drawings. In FIG. 14, the outer
sleeve 134 is located in the retracted position relative to inner
cylinder 132, such that the annular rim 152 of outer sleeve 134 is
positioned proximally from and out of engagement with the ramps 142
and 144 of the inner cylinder 132. The inner cylinder and outer
sleeve are connected together at their respective screw threaded
necks 140 and 150, whereby to expose the hypodermic needle 138 for
penetrating the skin of a patient, so that a phlebotomy tube (not
shown) may be infused with a sammple of the patient's blood. After
the last blood sample has been taken, and in order to avoid an
accidental needle strike, the outer sleeve 134 is grasped, below
flanged end wall 148, and pulled to the axially extended position
(of FIG. 15) relative to inner cylinder 132.
The axial advancement of outer sleeve 134 causes a corresponding
advancement of the rim 152, such that rim 152 travels up and across
the proximally oriented series of ramps 144. The continued axial
advancement of outer sleeve 134 relative to inner cylinder 132 will
cause rim 152 to be snapped into the gap 146 between ramps 142 and
144. A positive selflocking feature is thereby established, because
the rim 152 of outer sleeve 134 is securely and permanently
retained within the gap 146 between the most elevated portions of
ramps 142 and 144. Hence, the ramps 142 and 144 form stops to
prevent both the continued axial advancement and possible
detachment of the outer sleeve 134 from the inner cylinder 132 as
well as an inadvertent return of the outer sleeve 134 to the
retracted position of FIG. 14. Therefore, a disposal cartridge is
created (in FIG. 15) having the inner cylinder 132 and outer sleeve
134 locked in the axially extended position with the hypodermic
needle 138 completely surrounded and shielded, so that the syringe
130 may be safely handled while avoiding an accidental needle
strike and the possible spread of a contagious disease.
FIGS. 19-23 of the drawings show a fifth embodiment of the present
invention for a safety syringe. The syringe 160 of FIGS. 19-23
includes an inner cylinder and outer protective sleeve which are
coaxially aligned and axially extensible relative to one another
from a retracted position (of FIG. 19) to an axially extended
position (of FIG. 20). As is best illustrated in FIG. 23, the outer
sleeve 134 of syringe 160 is identical to the outer sleeve which
was previously described when referring to the syringe 130 of FIGS.
14-18. Therefore, identical reference numerals will be used to
describe the outer sleeve 134 of FIGS. 19-23, and the details
thereof will be omitted. Likewise, the screw threaded hub 136 and
hypodermic needle 138 of syringe 160 are identical to those of the
syringe 130. Therefore, identical reference numerals will also be
used to refer to hub 136 and needle 138.
As is best shown in FIG. 21, the inner cylinder 162 of the syringe
160 has a hexagonal cross-section comprising a plurality of
contiguous sidewalls. Inner cylinder 162 also has an open flanged
proximal end for receiving an evacuated phlebotomy tube (not shown)
and a substantially closed distal end wall. The hypodermic needle
carrying hub 136 is retained within a distal bore formed through a
neck 163 which extends from the distal end wall of inner cylinder
162, whereby one end of needle 138 projects outwardly from the
inner cylinder, and the opposite end of needle 138 projects into
the cylinder for communication with the phlebotomy tube.
Coextensively formed with and projecting outwardly from the distal
end of inner cylinder 162 are first and second series of short
ramps 164 and 166 (best illustrated in FIG. 22). The first series
of ramps 164 project outwardly in a first direction from the
respective intersections of adjacent sidewalls which define
hexagonal inner cylinder 162. A second series of ramps 166 are
spaced proximally from ramps 164 and project outwardly in a second
direction from the respective intersections of the sidewalls of
inner cylinder 162. As is best shown in FIG. 21, an angle of
approximately 120 degrees is formed between the first and second
directions in which the first and second series of ramps 164 and
166 respectively extend from the intersections of the sidewalls of
inner cylinder 162. Ramps 164 slope upwardly in a proximally
oriented direction, and ramps 166 slope upwardly in a distally
oriented direction, such that the most elevated ends 164 and 166
oppose one another to establish a narrow, annular gap 168 in the
space therebetween.
The operation of the syringe 160 is now described while continuing
to refer to FIGS. 19-23 of the drawings. In FIG. 19, the outer
sleeve 134 is located in the retracted position relative to inner
sleeve 162, such that the annular rim 152 of outer sleeve 134 is
positioned proximally from and out of engagement with the ramps 164
and 166 of the inner cylinder 162. The inner cylinder and outer
sleeve are connected together at their respective screw threaded
necks 163 and 150, whereby to expose the hypodermic needle 138 for
penetrating the skin of a patient so that a phlebotomy tube (not
shown) may be infused with a sample of the patient's blood. After
the last blood sample has been taken, and in order to avoid an
accidental needle strike, the outer sleeve 134 is grasped, below
flanged end wall 148, and a pulled to the axially extended position
(of FIG. 20) relative to inner cylinder 162.
The axial advancement of outer sleeve 134 causes a corresponding
advancement of the rim 152, such that rim 152 travels up and over
the proximally oriented series of ramps 166. The continued axial
advancement of outer sleeve 134 relative to inner cylinder 162 will
cause rim 152 to be snapped into the gap 168 between ramps 164 and
166. A positive self-locking feature is thereby established,
because the rim 152 of outer sleeve 134 is securely and permanently
retained within the gap 168 between the most elevated portions of
ramps 164 and 166. Hence, the ramps 164 and 166 form stops to
prevent both the continued axial advancement and possible
detachment of the outer sleeve 134 from the inner cylinder 162 as
well as an inadvertent return of the outer sleeve 134 to the
retracted position of FIG. 19. Therefore, a disposal cartirdge is
created (in FIG. 20) having the inner cylinder 162 and outer sleeve
134 locked in the axially extended position with the hypodermic
needle 138 completely surrounded and shielded, so that the syringe
160 may be safely handled while avoiding an accidental needle
strike and the possible spread of a contagious disease.
It will be apparent that while preferred embodiments of the present
invention has been shown and described, various modifications and
changes may be made without departing from the true spirit and
scope of the invention.
* * * * *