US 3712302 A
A needle guard for disposable syringes, the needle guard provided with a portion of reduced thickness so that the needle guard may be flexed to facilitate breaking of the needle encased in the needle guard.
Description (OCR text may contain errors)
United States Patent 91 Burke et al.
[ 1 Jan. 23, 1973  FLEXIBLE NEEDLE GUARD FOR BREAKING SYRINGE NEEDLES  Inventors: George K. Burke; Kenneth Raines,
both of Bethlehem, Pa.
 Assignee: Burron Medical Products, Inc.,
 Filed: Sept. 2, 1970  Appl. No.: 68,937
 US. Cl ..l28/221, 128/218 N, 225/5  Int. Cl. ..A6lm 5/00, A6lm 5/04  FieldofSearch.l28/22l,218 R,2l8 P,218 PA, 128/218 N, 218 NV, 218 M, 218 D, 214,
 References Cited UNITED STATES PATENTS 3,523,530 8/1970 Pagones et a1 ..l28/221 3,434,473 3/1969 Smith ..l28/22l 3,333,682 8/1967 Burke ..l28/22l 2,725,057 11/1955 Lockhart ..l28/2l8 NV 3,320,954 5/1967 Cowley ..128/221 FOREIGN PATENTS OR APPLICATIONS Great Britain ..l28/22l Germany ..l28/218 M Primary ExaminerRichard A. Gaudet Assistant Examiner-J. C. McGowan Att0rney-Shoemaker and Mattare  ABSTRACT A needle guard for disposable syringes, the needle guard provided with a portion of reduced thickness so that the needle guard may be flexed to facilitate breaking of the needle encased in the needle guard.
13 Claims, 6 Drawing Figures PATENTEDJANZS I975 3.712.302
IN VENTOR 7 GEORGE K. BURKE a KENNETH RAINES BY a 4 ATTORNEYS FLEXIBLE NEEDLE GUARD FOR BREAKING SYRINGE NEEDLES BACKGROUND OF THE INVENTION This invention relates to needle guards for disposable syringes. More particularly, this invention relates to disposable hypodermic syringes which are intended to introduce a single dose of medication into a patient and subsequently the syringe is mutilated so as to be easily disposed of in order to prevent the used hypodermic syringe from falling into the hands of children or narcotics addicts or the like.
Heretofore, various constructions have been employed with hypodermic syringes to facilitate the mutilation of various components of the syringe in order to prevent the syringe from being reused. Such constructions are disclosed, for example, in U.S. Pat. No. 3,320,954, which employs a score line in the Luer adaptor 3 whereby theadaptor may be broken to separate the needle from the syringe. Similarly, U.S. Pat. No. 3,306,291 utilizes a specific construction at the juncture of the adaptor 46 and barrel 40 of the syringe for facilitating breaking of the adaptor from the syringe to separate the needle therefrom and prevent reuse of the syringe. Both of these constructions leave the needle intact, and it is quite possible for the needle to be reused if it should fall into the hands of a narcotics addict or the like.
It is important that means be provided for readily rendering both the syringe and the needle inoperable after they have been used in order to prevent their reuse and the likelihood of infection caused by the use of contaminated needles or syringes. For example, if the needle has been used on a patient infected with hepatitis and is then reused by another'patient, the patient using the contaminated needle is almost certain to be infected with the disease.
The present invention economically and effectively overcomes these problems by providing a needle guard for protecting the needle both to maintain it in a sterile condition prior to its use and, also, to protect a nurse handling the hypodermic syringe from a puncture by the sharpened point of the needle, the needle guard being particularized in including a portion of reduced thickness adjacent the needle hub acting as a living hinge to facilitate flexure of the needle guard in opposite directions at a specific point relative to the needle in order to bend the needle back and forth to break it off and thus render the needle unusable, while maintaining the integrity of the needle guard.
Additionally, the present invention may incorporate means for breaking the syringe portion as described fully in U.S. Pat. No. 3,306,291. In prior art hypodermic syringes, the needle is either left intact or is bent or broken manually with great difficulty and with considerable danger to the nurse breaking the needle since the needle guard must first be removed in order to flex the needle to break it. Expensive equipment is sometimes resorted to to destroy the needle by cutting action.
In the present invention, on the other hand, the needle guard is left in place and the needle may be broken quite safely and easily merely by flexing the needle guard back and forth in order to break off the needle which is fully protected at all times inside the needle guard.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view in elevation of the needle guard according to the present invention in position upon the hub of a needle assembly.
FIG. 2 is a cross-sectional view in elevation taken along the line 22 in FIG. 1.
FIG. 3 is a cross-sectional view in elevation taken along the line 3-3 in FIG. 1.
FIG. 4 is a schematic view illustrating the manner in which the needle guard and needle are flexed back and forth.
FIG. 5 illustrates the needle guard flexed to one side with the needle broken off from the hub portion.
FIG. 6 is a sectional view of a modification of the present invention.
DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, wherein like reference numerals refer to like parts throughout the several views, the needle assembly according to the present invention is indicated generally at l in FIG. 1. The needle assembly comprises a conventional syringe 2 having a forwardly extending projection 0r adaptor 3 with a Luer taper 4 thereon for receiving the hub of a needle thereover. The needle hub 5 includes an inner taper 6 for cooperative engagement with the Luer taper 4. A cannula 7 having a sharpened end is received in the forward end of needle hub 5 and the opposite end thereof includes a pair of oppositely directed lugs 8 and 9 for cooperative interengagement with an internally threaded Luer lock adaptor 10. The adaptor 3 is joined with syringe 2 at an area of localized stress as more fully described in copending application Ser. No. 359,674 filed Apr. 14, 1964, and now U.S. Pat. No. 3,306,291, in order to enable the adaptor 3 to be broken away from the syringe 2 to render the syringe inoperable.
The unique and novel needle guard of the present invention is indicated generally at 11 and comprises an elongate tubular body 12 generally cylindrical in crosssection and having a closed end and an open end, the open end including a base portion 13 having a needle hub engaging portion 14 and a diametrically enlarged portion 15 joined to the needle hub engaging portion by a frusto-conical surface 16. A radially extending marginal flange 17 is formed on the rear of portion 15 to aid in the manipulation of the needle guard in placing it on or removing it from the needle assembly and to reinforce the needle guard. The closed end of the elongate body 12 has a reduced outside diameter in relationship to needle hub engaging portion 14 and is joined thereto by a frusto-conical shoulder 22. A plurality of radially extending elongate reinforcing ribs l8, 19, 20 and 21 extend from shoulder 22 to adjacent the closed end of the needle guard to reinforce the needle guard against accidental flexure and also to provide a surface on the needle guard which may be securely grasped to facilitate the torqueing or wrenching of the needle guard on the needle hub and the removal of the needle guard therefrom.
The wall of elongate body 12 is substantially reduced in cross-sectional thickness adjacent needle hub engag ing portion 14, and includes a straight land portion 23 on the inner surface thereof extending from the needle hub engaging portion 14 longitudinally toward the closed end of the body the distance, for example, on the order of 0.062 inches. The wall of body 12 at the straight land portion has a thickness, for example, on the order of 0.010 inches. The remaining extent of elongate body 12 is gradually tapered from the end of the straight land portion to the closed end of the body and has a maximum thickness at the closed end, for example, of about 0.035 inches. The area of reduced thickness defines a weakened portion which in effect acts as a living hinge whereby the needle guard may be flexed back and forth about such portion adjacent the hub engaging portion 14 by exerting lateral pressure thereon as seen in FIG. 4. The living hinge permits flexure of the needle guard through an angle of at least approximately 30 as seen in FIG. 4, even though the reinforcing ribs 18, 19, 20 and 21 are provided thereon and in fact, the ribs themselves are flexed or bent as seen in FIGS. 4 and 5.
FIG. 2 shows the cross-sectional shape of the needle guard at the area of reduced thickness and shows the disposition of the reinforcing ribs about the outer surface thereof.
As best seen in FIG. 3, the inside surface of needle hub engaging portion 14 is hexagonally shaped and has a plurality of straight sides 24 which cooperate with a complementary shaped surface 25 on the needle hub 5 whereby the needle hub may be wrenched into position on adaptor 3 with the radially extending lugs 8 and 9 on the end of needle hub 5 in cooperative locking engagement with the internal threads in the Luer lock adaptor 10. A pair of diametrically opposite ribs 26 and 27 are formed on the inner surface of needle hub engaging portion 14 to compensate for slight dimensional variations in the needle hub for assuring a tight fit between the hub and guard. The substantially reduced cross-sectional thickness of body 12 adjacent shoulder 22 in comparison with the thickness of body 12 at needle hub engaging portion 14 is apparent in these figures.
Referring now specifically to FIGS. 4 and 5, the manner in which the needle guard is flexed at the area of reduced thickness to break the needle is illustrated. The normal disposition of the needle and needle guard is shown at position C with the guard concentrically spaced from the needle. The needle guard is shown flexed upwardly against the needle bending the needle upwardly at position D and is shown flexed downwardly against the needle bending the needle downwardly at position E. The needle guard and needle are flexed in opposite directions several times until the needle snaps off as shown in FIG. 5.
Because of the ribs 18, 19, and 21, the needle guard is sufficiently structurally rigid to effectively protect the needle 7 and effectively prevents flexing thereof at any point other than the weakened portion; yet the weakened portion at 23 permits the needle guard to be readily flexed to break the needle with the needle guard in position, thus avoiding any danger to the person breaking the needle from puncture as he flexes the needle in order to break it. The needle guard is formed from flexible plastic material, such as vinyls, although it is preferably made of polypropylene and such material is relatively stiff and normally very difficult to bend and break. The weakened portion 23 provides a means whereby the guard may be readily flexed and, moreover, the positioning of the weakened portion adjacent the hub of the needle when the needle guard is in position on the needle hub insures that the needle will be broken off close to the hub, thus preventing the broken needle from being effectively resharpened and reused.
FIG. 6 illustrates a modified needle guard wherein the guard is provided with a V-shaped notch or groove about the periphery of the guard. The groove 28 is positioned preferably approximately in line with the end of the needle hub such that flexing the guard through the notch will result in the breakage of the cannula at its juncture with the hub.
As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive.
1. A needle assembly comprising: a cannula having a sharpened end, a needle hub on the other end of said cannula, and a plastic needle guard fitted over said cannula and over said needle hub, said needle guard including a portion of reduced wall thickness adjacent the needle hub and between the hub and cannula pointed end so that the needle guard and sharpened cannula may be flexed back and forth at said section of reduced thickness to break the cannula adjacent the needle hub, said section having sufficient toughness and flexibility and being of a thickness to allow deflection of the needle guard through an angle of at least approximately 30 so as to break the cannula at said section of reduced thickness while maintaining the integrity of the needle guard with the needle guard in position over the cannula while the cannula is being broken and after the cannula is broken.
2. A needle assembly as in claim 1, wherein the wall thickness of the needle guard increases gradually from the portion of reduced thickness adjacent the needle hub engaging portion to the closed end thereof.
3. A needle assembly as in claim 2, wherein the portion of reduced wall thickness includes a straight land portion adjacent said needle hub engaging portion.
4. A needle assembly as in claim 3, wherein the straight land portion is approximately 0.062 inches long.
5. A needle assembly as in claim 4, wherein the wallv thickness of said needle guard at said straight land portion is approximately 0.010 inches.
6. A needle guard adapted to be fitted over and enclose a needle comprising: a generally tubular body having a closed end an open end, said open end defining a needle hub engaging portion adapted to be fitted over the hub of a needle confined within said needle guard, said needle guard including a portion of reduced wall thickness between said needle hub engaging portion and said closed end so that said needle guard may be flexed back and forth at said portion to break a needle which is encased in said needle guard, said section having sufficient toughness and flexibility and being of a thickness to allow deflection of said needle guard through an angle of at least approximately 30 so as to break the cannula at said section of reduced thickness while maintaining the integrity of the needle guard with the needle guard in position over the needle while the needle isbeing broken and after the needle is broken.
7. A needle guard as in claim 6, wherein said portion of reduced wall thickness includes a straight land portion extending from said needle hub engaging portion toward said closed end.
8. A needle guard as in claim 7, wherein the wall of said needle guard gradually increases in thickness from said portion of reduced wall thickness to said closed end.
9. A needle guard as in claim 8, wherein a plurality of longitudinally extending reinforcing ribs are disposed on the outer surface of said needle guard.
10. A needle guard as in claim 9, wherein said straight land portion extends from said hub engaging