Safety syringe

Abstract

A safety syringe for one-time use including a plunger which is permanently lockable by detent members and a slidable needle cap which is also permanently lockable by detents to prevent reuse.

Description

BACKGROUND OF THE INVENTION

The field of this invention is safety syringes.

Drug addiction is certainly one of today's great and continuing tragedies. Many of the particularly dangerous drugs are taken through injection with a syringe. Very often the syringes used by drug addicts are stolen or otherwise removed from medical centers such as hospitals. In addition to implementing the drug habit, used syringes are a source of disease and infection.

U.S. Pat. No. 3,320,954 issued to Cowley discloses a hypodermic syringe having a breakable needle adapter for breaking off the needle end of the syringe. The Cowley syringe requires the user to find a suitable surface on which to break off the needle end and then to retrieve the broken-off end. The inconvenience involved in rendering the Cowley syringe inoperable tends to encourage users to simply discard the syringe in reusable condition.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a new and improved safety syringe which is easily and conveniently rendered unusable by activating locking mechanisms at both the plunger end and the needle end of the syringe. In the preferred embodiment of this invention, the safety syringe includes a barrel housing having a bore therethrough for receiving a plunger at one end and an ampul at the other end thereof. The plunger operates in a well known manner to displace fluid from the ampul needle into the body.

A protective cap is mounted over the needle end of the barrel housing and is movable inwardly in order to expose the needle. A cap safety lock means is provided for moving the protective cap outwardly over the needle and locking the cap against further inward movement after the syringe has been used. Further, a plunger lock means is provided for moving the plunger outwardly of said housing to a lockable position wherein the plunger lock means prevents movement of the plunger inwardly again. In this manner, both the needle end and the plunger end of the syringe are substantially deactivated to prevent further use thereof.

Further, the safety syringe of the preferred embodiment of this invention may include a barrel housing having mounted therein a plunger and ampul with a protective cap mounted over the needle initially. The protective cap is mounted for slidable movement with respect to the barrel housing such that the cap is movable inwardly to an exposed position. This feature of this invention prevents exposure of the needle until it is actually used thereby allowing the needle to remain sterilized until use and further providing some comfort to the patient by hiding the needle until it is actually used.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view in section of the safety syringe of the preferred embodiment of this invention prior to use thereof; and

FIG. 2 is a side view in section of the safety syringe with both ends thereof having been substantially deactivated after use thus rendering the syringe inoperable for further use.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, the letter S generally designates the safety syringe of the preferred embodiment of this invention. The safety syringe S basically includes a barrel-shaped housing 10 having mounted therein a plunger 11 for displacing medicinal fluid outwardly through needle 12 which is mounted with the medicine container or ampul 14. A plunger cap 15 is removably mounted over the plunger at the top end 10a of the housing and needle cap 16 is mounted over the bottom end 10b of the housing 10.

The housing 10 is basically cylindrical in cross-section and includes a main housing portion 10c which has a bore 10d therein. The bore 10d includes a plunger section 10e and an ampul section 10f. The plunger 11 includes an elongated or rod-like portion 11a which is integrally formed with an enlarged end portion 11b adapted to receive a thumb in a well known manner. Two annular ridges 17a and 17b are integrally formed with the plunger bore section 10e and extend radially inwardly to serve as guides for slidably mounting the plunger 11 for movement within the housing 10. Plunger safety lock means generally designated as 18 are mounted with the plunger 11 and the plunger bore section 10e in order to lock the plunger against re-entry into the ampul after the syringe has been used.

The plunger safety lock means 18 is provided by an annular groove 18a in the rod-like plunger portion 11a. The annular groove 18a includes an upper inclined locking face 18b. The plunger safety lock means 18 further includes a detent or annular ridge or stud 19 which extends radially inwardly from the plunger section bore 10e. The detent 19 includes an upwardly inclined detent locking face 19a which is adapted to engage the downwardly inclined groove locking face 18b in order to prevent downward movement of the plunger 11 after initial use.

The ampul 14 is of conventional construction and includes a plunger piston 14a of suitable material for receiving the plunger 11 and displacing the medicinal fluid outwardly through the needle 12. The ampul bore section 10f includes two annular ridges 20a and 20b which provide a friction fit for the ampul 14.

The housing 10 further includes an annular recess 10g formed by inner and outer cylindrical walls 10h and 10i. The annular recess 10g mounts the needle cap 16 for slidable movement therein. Annular guide ridges 21a and 21b extend radially inwardly from outer recess wall 10i for mounting the needle 16 for slidable movement within the recess 10g. The inner recess wall 10h has two annular ridges 25a and 25b that are integrally formed with the housing 10 and extend radially outwardly to cooperate with the ridges 21a and 21b to mount needle cap 16 for slidable movement.

The housing 10 includes circumferentially spaced openings 10j which extend to the annular recess 10g. The openings may be initially covered by a band 22 of a suitable plastic material. The band is removed at the time of use to allow air to enter and exit from the annular recess 10g so that the plunger 11 can be moved as desired.

The needle cap 16 includes an elongated, cylindrical body portion 16a integrally formed with the top 16b. The top 16b includes an opening 16c to receive the needle 12. The opening 16c is initially sealed off by a sealing membrane 24 for sterilization purposes. The cylindrical portion 16a of the needle cap 16 is mounted within the annular housing recess 10g for slidable movement inwardly and outwardly thereof between various positions. The upper end 16d of the cylindrical portion 16a is enlarged to further guide the cylindrical needle cap 16a in the annular recess 10g.

Outer, end wall portion 16f of the needle cap 16 is grooved to provide a gripping surface for the user to move the needle cap upwardly and downwardly within the recess 10g.

Safety lock means generally designated as 26 are mounted with the housing 10 in the recess 10g and with the needle cap 16 for locking the needle cap in the position illustrated in FIG. 2 such that the needle is not accessible for reuse. The safety lock means 26 includes two sets of detent means generally designated as 27 and 28. The first detent means 27 includes an annular, outwardly extending ridge or detent member 27a which is integrally formed with inside recess wall 10h. The annular detent member 27a includes an upwardly facing, inclined locking face 27b which fits in annular groove 27c in inside needle cap wall 16g.

The second detent means 28 includes an inwardly extending ridge or detent member 28a which is integrally formed with and extends inwardly from the outer recess wall 10i. With the needle cap in the position of FIG. 2, the annular ridge 28a fits in annular groove 28b in outer needle cap wall 16h. The annular ridge 28a includes a downwardly facing inclined locking surface 28c which engages a cooperating surface in the groove 28b and serves to prevent inward movement of the needle cap 16 after the needle cap has been moved to the position of FIG. 2. The annular locking ridges 27a and 28a provide first and second detent members for locking the needle cap 16 against movement either further into or further out of the housing recess 10g. In this manner, the needle 24 can be rendered inaccessible for subsequent use.

OPERATION AND USE

In operation and use of the safety syringe S of this invention, the plunger cap 15 is first removed from the top end 10c of the housing 10 in order to expose the plunger 11 for use. The needle cap end 16b is then placed firmly against the body and the user presses firmly downwardly against the housing shoulder 30 to move the entire housing downwardly with respect to the needle cap 16 such that the needle 12 will break through the membrane 24 and enter the body. Thus, the cylindrical needle cap portion 16a moves inwardly into housing recess 10g in order to retract the needle cap 16 and expose needle 12. The needle cap 16 moves inwardly until the end 16b substantially abuts the bottom housing end 10b. The needle cap 24 thus eliminates some of the fear which patients may have from observing the needle by eliminating the need to expose the needle prior to entry of the needle into the body.

After the needle 12 has entered the body, the user then presses the plunger 11 to move the plunger 11 into the ampul 14 and displace the medicinal fluid therein outwardly through the needle 12 into the body in a known manner. After the injection is completed, the entire syringe S is pulled away from the body. The plunger 11 is then moved upwardly in the direction of arrow 31 outwardly of the housing 10 and the plunger bore section 10e to the lockable position illustrated in FIG. 2, or even to a position further outwardly thereof.

The needle cap 16 is then gripped at 16f and moved outwardly of the housing recess 10g to the lockable position illustrated in FIG. 2. In this lockable position, the first annular locking ridge 27a is positioned within the needle cap groove 27c such that the locking face 27b, which extends upwardly at an inclined angle, engages top groove face 27d to prevent any movement of the needle cap 16 outwardly of the recess 10g.

The detent means 28 locks the needle cap 16 against further movement inwardly into the housing recess 10g. The annular locking ridge 28a extends into the groove 28b in the outer needle cap wall 16h such that the downwardly facing, inclined locking face 28c engages bottom groove face 28d thereby preventing anyone from moving the plunger 16 further into the recess. This safety cap locking means 26 thus serves to lock the needle cap 16 in the lockable position of FIG. 2 such that the needle 12 is rendered inaccessible for subsequent use. The syringe S can now be safely disposed of without fear of anyone making later use thereof.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.

The various structures such as the housing 10 and the plunger 11 of this invention are, in the preferred embodiment, polyethylene or polypropylene or other suitable synthetic material. However, it should be understood that any suitable material can be utilized to provide an inexpensive, light-weight safety syringe.

Claims

I claim:

1. A lockable safety syringe, comprising:

a barrel housing having a bore therethrough, said barrel housing bore being adapted at one end thereof to receive a container for medicine having a needle mounted therewith for protrusion outwardly from said barrel housing;

a plunger mounted in said barrel housing bore at the other end thereof for slidable movement, said plunger being movable into said container for medicine for displacing medicine in said container outwardly through said needle;

a protective cap mounted on said one end of said barrel housing over said needle;

cap safety lock means for locking said protective cap over said needle to prevent reuse of said syringe; and

plunger safety lock means for locking said plunger against movement to prevent reuse of said plunger whereby said plunger safety lock means cooperates with said cap safety lock means to prevent reuse of said syringe, said cap safety lock means and said plunger safety lock means being located within said housing so as to be inaccessible after locking each of said means.

2. The structure set forth in claim 1, including:

said plunger being movable from an initial position to a position further into said housing bore for injecting medicine into a person;

said plunger further being movable further outwardly of said housing from said initial position to a lockable position; and

said plunger safety lock means comprising

detent means mounted with said plunger and housing bore to prevent movement of said plunger inwardly of said housing bore from said lockable position.

3. The structure set forth in claim 1, including:

mount means mounting said protective cap for slidable movement from an initial position over said needle to a retracted position inwardly of said housing in which said needle is exposed for use.

4. The structure set forth in claim 3, including:

said mount means mounting said protective cap for movement outwardly of said housing from said retracted position to a protective position over said needle.

5. The structure set forth in claim 4, including:

said cap safety lock means locking said protective cap in said protective position against movement inwardly of said housing to prevent further exposure of said needle.

6. The structure set forth in claim 5, wherein said cap safety lock means includes:

said barrel housing having an annular recess therein which receives said protective cap; and

detent means mounted within said recess of said housing for permanently locking said cap safety lock means.

7. The structure set forth in claim 1, including:

said housing including an annular recess; and

said protective cap including a cylindrical portion mounted in said annular recess for slidable movement with respect to said housing.