Hypodermic Syringe With Means to Destroy and Safely Store the Cannula

The present invention relates to a device for the safe destruction and storage of used cannulas and especially the safe destruction and storage of cannulas of hypodermic syringes suitable for sampling blood or injecting therapeutic medications and are adapted to be used only once.

Cannulas and equipment used for injecting therapeutic fluids frequently are disposable and designed to be discarded after a single use. Once a cannula has been used to inject a medication, it is contaminated. The sharp point on a contaminated needle can injure people in that it cause the spread of disease among those that handle it. Infectious diseases such as HIV or hepatitis viruses have been transmitted to people who handle contaminated needles and accidentally stick themselves with them. Small residues of blood and viruses on the cannula from an infected patient can result in transmission of a disease that the patient has contracted to a staff member

In the past, relatively complex arrangements have been devised to prevent the accidental infections from contaminated needles. I have found that covering of sharp points and destruction of the cannulas to prevent reuse is highly desirable because hypodermic needles are frequently reused by drug abusers and accidental contact or intentional use must be eliminated.

Exemplary of devices which have attempted to solve these problems is the application of Ameur: Int Pub. No. WO89/11304; PTC/SE89/00290. The application discloses a pair of protective sleeves that are displaceable in a longitudinal direction over a holder that is provided for a double pointed cannula. The sleeves serve as adapters that provide a bayonet socket which is fitted into another bayonet socket. The arrangement is used with a sample holder which has steps formed in an end to receive a peg that holds the arrangement together during use. As viewed, the sleeves of the cannula can easily move and expose the needle after use when it is contaminated Moreover, the arrangement requires the provision for a specially designed sample holding device to accommodate the sleeves and even with this fairly complex combination, the needle is not destroyed after use.

In the U.S. Pat. No. 4,366,544, to Wardlaw, patentee describes a hypodermic syringe which has provision for preventing more than one use and rendering the needle inoperative. According to the Wardlaw patent, a mechanism is mounted on the syringe which, after administering the injection, is manipulated to bend the needle of the syringe at right angles to the needle and concurrently retract it from its normally projecting position to a second position in which it is housed in a containment area. The retraction is accomplished by twisting a cap around a post so that the needle is permanently deformed and wrapped around the post. While protection of the needle point and destruction of the needle is provided with the mechanism, significant torque is required to twist the cap to urge the needle around the post to destroy and house it The amount of torque necessary to accomplish the wrapping and housing can exceed the strength of the various plastic parts.

Capping arrangements such as shown in Lemelson, U.S. Pat. No. 4,273,123; Karmen et al, U.S. Pat. No. 3,747,812; and Cuu, U.S. Pat. No. 4,634,428, all involve an ancillary cap over the cannula to bend or distort the metal. Similarly, the U.S. patent to Koening, U.S. Pat. No. 3,893,608, discloses a syringe that is fitted onto a cover to distort it through the placement of a post surrounding by an annular ring.

According to the present invention, I have found that after use of a hypodermic syringe, the disposition of the cannula in a hollow housing with a means to draw the cannula into the housing (preferably around a reel fitted in the housing) can enable the user to simultaneously destroy the cannula, store it and prevent accidental contact with the sharp point of the needle. After the syringe has been used, the reel is turned to draw the cannula into the housing and wrap it around the reel so that the cannula is destroyed and the point is stored within the housing When drawn into the housing and wrapped, I have further found that a positive indication of complete enclosure of the sharp point is provided by the feel and sound of the point snapping against the inside of the housing which indicates that the syringe is safe to be disposed of without potential injury. The hypodermic syringe and the housing is preferably formed of molded styrene, polycarbonates, polyamides or polyethylene.

FIG. 1 is a perspective view of an embodiment of the hypodermic syringe of the present invention in which the cannula can be used and then destroyed and stored;

FIG. 2 is a cross-sectional view of an embodiment of the invention taken along the line 2--2 of FIG. 3 (following the cannula) in which a cannula having one point is disposed within a housing and through a reel;

FIG. 3 is a cross-sectional view of the embodiment shown in FIG. 2. In this view, the syringe has been turned -90.degree. from the FIG. 2 view;

FIG. 4 is an enlarged fragmentary view of the reel shown in FIG. 3. In this view, the cannula has been wrapped about the reel, destroyed and stored within the housing;

FIGS. 5 and 6 are cross-sectional views of another embodiment of the present invention. In this embodiment, the end of the cannula is detachably disposed within a bottom wall of the hypodermic syringe and through a reel. FIGS. 5 and 6 are of the same embodiment, except that the cross sections are offset from each other by 90.degree..

The embodiments shown in FIGS. 7 and 8 are similar to the embodiment shown in FIGS. 5 and 6, except that the blunt end of the cannula is seated in the bottom wall of the hypodermic syringe with a sealing means. Again, one cross section is offset from the other by 90.degree..

Referring now to FIG. 1, a cannula 1 is shown together with a hypodermic syringe 2. A plunger 4 is disposed within the transparent barrel 6, as is well known. The lower end of the hypodermic syringe includes a reel that is rotatably disposed inside a housing H (and shown in enlarged cross-sectional views in FIGS. 2 to 8). A handle 24 is integrally attached to the reel so that twisting the handle 24 will turn the reel and cause cannula 1 to be withdrawn through an aperture in a nose 8 of the housing H for destruction and storage.

Referring to FIGS. 2, 3 and 4, the cannula 1 is

shown having two ends (herein called a receiving end E.sup.1 and a dispensing end or point E.sup.2). Part of the cannula 1 is disposed in a hollow housing H. The nose 8 of the housing H has the general shape of a nipple with an opening 11A to receive the cannula 1. An upper end 4 of the housing H is formed beneath a bottom wall 10 of the hypodermic syringe which also forms the bottom of the interior I of the syringe.

The cannula 1 is slidably disposed in the aperture 11A in the nose 8 and extends outwardly therefrom for use in injecting medications. Another portion of the cannula 1 is fixedly disposed within a throughhole 13A that is formed in reel 13. Such fixed disposition of cannula 1 can be accomplished by many means which can include the application of adhesive or simply molding the reel 13 about the cannula 1. Reel 13 is rotatably disposed within the housing H and rotates about an axis A--A which is preferably at right angles to the cannula 1 so that when the reel 13 is turned, it bends at point B and then wraps around the reel 13 (as shown in FIG. 4). Reel 13 is surrounded by a containment area C. Since cannula 1 is slidably disposed within aperture 11A, as the point E.sup.2 is retracted into a containment area C in the housing H it is safely stored.

The interior I of the hypodermic syringe is in fluid flow communication with a lumen in the cannula 1 by means of an opening 20 disposed in the bottom wall 10. The opening 20 has a step adjacent the reel 13 to receive an O-ring 21 that surrounds it and urges against the reel 13 to prevent leakage into the spaces between the reel 13 and the interior of the housing H. Upon application of pressure to plunger 4, the medication will be urged into the lumen of cannula 1 to flow out of point E.sup.2 of cannula 1. On the other hand, when fluids such as blood are to be withdrawn from a patient, the withdrawal of plunger 4 from the interior I of the hypodermic syringe will cause the blood flow into point E.sup.2 and emerge at end E.sup.1 to flow into the interior I of the hypodermic syringe. In this embodiment, the end E.sup.1 of the cannula 1 is shown to be flush with the outside of the reel 13 to enable reel 13 to be turned easily about its axis. In other embodiments, however, the flush disposition of end E.sup.1 relative to reel 13 may not be necessary, as will be seen in later embodiments.

As shown in FIG. 3, reel 13 is fitted in housing H so that the end with the handle 24 passes through a side wall and the other end is rotatably disposed in the opposite side wall. A step 13B is formed on reel 13 to provide for a space between reel 13 and containment area C for storage of the cannula 1.

As shown in FIG. 4, the containment area C provides space for the cannula 1 when it is wound upon reel 13. Point E.sup.2 is safely stored within containment area C and cannot be touched after the cannula 1 is wound. At the same time, the O-ring 21 continues to urge against the portion of the reel 13 having the larger diameter to prevent the seepage of fluids.

As shown in FIG. 3, the cannula 1 is bent at point B at an angle necessary to place end E.sup.1 beneath opening 20 in the bottom wall 10. Bending the cannula 1 at the predetermined angle enables the O-ring 21 to cover the area around cannula 1 where it emerges from the reel 13. The angle that the cannula 1 is bent is not critical so long as the end E.sup.1 is disposed beneath the opening 20 and the O-ring 21. The longitudinal axis of the cannula 1 is at right angles to the axis of rotation A-A of the reel 13.

Referring now to FIGS. 5 and 6, another embodiment of the invention is shown. In this embodiment, the cannula 1 extends into a generally conically shaped opening 20A having a very narrow apex angle. The end E.sup.1 of the cannula 1 is snugly force fit into the opening 20A (which is drawn somewhat exaggerated in order to show the conical shape). The essential feature, however, is that the cannula 1 is detachably removable from the opening 20A and will not allow the flow of fluids from the interior I of the syringe into the containment area C while the plunger 4 is being pushed. As in the previous embodiment, the point E.sup.2 extends from the nose 8 of the housing H. Upon turning reel 13 about axis A, the cannula 1 will bend at points B and will wrap itself around reel 13. End E.sup.1 will be drawn through opening 20A and simultaneously point E.sup.2 will be drawn up into aperture 11A in the nose 8. Continued twisting of the reel 13 about its axis will eventually cause the point E.sup.2 to be fully withdrawn into containment area C. When the cannula is fully withdrawn into containment area C, point E.sup.2 will snap against the interior walls of containment area C, thereby giving an audible and tactile sensation that it is fully withdrawn and safely stored.

Another embodiment of the present invention is shown in FIG. 7 and 8. This embodiment is substantially the same as the one shown in FIGS. 5 and 6, except that cannula 1 extends through the opening 20B in bottom wall 10 and is detachably held in place by a small dab of adhesive 20C or with an O-ring or washer that has been snugly fitted over the end E.sup.1 and will butt with an aperture 20D so as to prevent leakage into or from the interior I of the syringe. Twisting reel 13 about its axis A--A will break the adhesive bond (or remove the cannula 1 from the O-ring or washer) in opening 20B and cannula 1.

It is apparent that modifications and changes can be made within the spirit and scope of the present invention but it is my intention, however, only to be limited by the scope of the appended claims.