US3390759A - Shield and hub for disposable needle - Google Patents

Description

July 2, '1968 I R. c. VANDERBECK SHIELD AND HUB FOR DISPOSABLE NEEDLE Filed May 25, 1967 ATTORNEYS United States Patent 0 3,390,759 SHIELD AND HUB FOR DISPOSABLE NEEDLE Russell C. Vanderbeck, Saddle River, N.J., assignor to Becton, Dickinson and Company, East Rutherford, N.J., a corporation of New Jersey Filed May 25, 1967, Ser. No. 641,236 5 Claims. ((11. 206-43) ABSTRACT OF THE DISCLOSURE A hub for supporting the needle cannula of a hypodermic syringe having a pair of diametrically opposed, straight, radially outwardly directed ribs and a shield with a locking ring formed internally thereof for mounting, in coaxial relation, the shield 0n the hub to envelop the cannula. The outer diameter of the ribs is greater than the internal diameter of the ring thereby to provide a selfsus-taining interference fit between parts.

Background of the invention Medical apparatus, such as the type contemplated by the present invention, is generally offered for commercial distribution in a sealed sterile package; sterilization being carried out in accordance with any one of the procedures well-recognized in the field. Further, the components are generally in the assembled condition within the package. In this manner the assembled package contents tend to remain in the sterile condition for a longer period of time. Additionally, when mounting on a syringe for use, in the case of packaged needle cannula structure, a shield encased cannula may be handled without any great fear of injury. Further, the needle cannula structure may rather easily be mounted on the syringe my implementation of the shield. Further still, there is no unnecessary handling and consequent contamination of the needle.

A problem of shield drop-off or loosening from the hub structure often times develops with many of the prior art devices packaged for distribution in the assembled condition. This is due to the fact that the mating fit between parts is, in the prior art, accomplished by interacting male and female tapered surfaces on the hub and shield, respectively. Thus, following sterilizing or during aging the normal relaxation of the components, under varying conditions of stress due to their particular structural configuration, causes either a complete or partial loss of interference and consequently shield drop-off or loosening. As a result possible injury, due to the presence of an uncovered cannula, may be inflicted on the user when opening the sealed package. Also, the uncovered cannula may be accidentally contaminated. Both conditions are to be prevented.

Summary of the invention The present invention seeks to overcome the aforementioned problems and disadvantages of many prior art structures which are prepared for the market in sterile packages. In a broad sense the invention contemplates a hub element having a bore within which a hypodermic syringe needle cannula is adapted to be 'both received and fixedly supported. The hub is defined by a skirt portion and a neck portion integral therewith and of reduced diameter. At least one pair of diametrically opposed raised ribs that smoothly flow from the skirt are disposed on the neck and traverse substantially its entire length. The ribs are formed such that all points on one surface are substantially equidistantly radially spaced from respective points on the other rib surface and lie on a cylindrical plane generated by revolving the hub about its longitudinal axis. A relatively less rigid elongated shield member is adapted to be coaxially received, by an interference fit, on the hub to completely enclose the cannula. The shield is formed with an internal locking ring having a minor diameter which is smaller than the diameter of the cylindrical plane. Thereby, upon mounting, the shield undergoes an outward fiexure at the ring which, upon partial recovery to the original shape, provides a tight fit in the area of interference between the ring and ribs.

Accordingly, it is a main object of the present invention to provide means on hub and shield structure which interact in a manner to provide a tight interference fit between mutually flat-sided structure thereby to minimize or eliminate the possibility of shield drop-off or loosening upon normal relaxation of parts after sterilization and during aging.

Other objects and advantages of the present invention will become apparent to those skilled in the art as the following description, to be read in conjunction with the figures, is developed.

Brief description of the figures The accompanying drawing forms a part of this invention. By these drawings:

FIGURE 1 is an exploded view in side elevation and partly in section of a hub and shield member;

FIGURE 2 is an elevational view partly in section of the components as shown in FIG. 1 in the mounted position; and

FIGURE 3 is a view as seen along the line 33 in FIG. 2.

Brief description of the preferred embodiment Referring now to the drawing, FIG. 1 shows a hub 10 which may be mounted, in theconventional manner, to the barrel of a hypodermic syringe (not shown) and a shield 12 that is received upon the hub member to completely envelop a cannula 14 supported by the latter. While not shown in the drawings the hub and shield members may be disposed in a suitbale package for shipment and storage. Pack-ages of this sort are well known in the art and generally the components will be assembled as in FIG. 2. It is also well known that the structure may be sterilized before or after packaging by, as for example, ethylene oxide and the packaged assembly will retain such sterility while within the sealed package.

The hub 10 may be formed from one of the relatively hard, rigid non-yieldable plastic materials, such as polystyrene, a high molecular weight polypropylene, etc., or metal, all of which are commercially available. In the preferred embodiment polypropylene is used. The hub is of unitary construction and may be developed by a moulding or equivalent process.

As generally shown the hub is formed thereby to provide a central opening coincident with its axis for both the receipt of cannula 14 and the hubs receipt on a syringe barrel. The particular manner by which the cannula is rigidly and fixedly secured to the hub is not particularly important for an understanding of the present invention. Therefore, the cannula mounting is not shown in the figures. Generally, though, the central opening through the hub member may be formed to provide one or more cavities which are suitably filled with an epoxy system resin or other resin to essentially Weld the cannula to the hub, thus, fixedly securing the same in the desired position. The cannula, properly positioned, projects from the neck of the hub member to locatethe sharp puncturing lumen in a position removed therefrom. In the present invention the shield 12 is provided to completely envelop the projecting cannula. The other cannula end terminates within the neck bore and communicates with the enlarged central opening in the hub.

The hub 10 is configured to provide a skirt portion 16 and a neck portion 18. The skirt portion defines approximately one half of the hub 10 and is generally frustoconical in configuration. At approximately the hub center point the skirt slopes inwardly forming the neck which is generally cylindrical and of a diameter smaller than the narrowest skirt dimension.

In a manner similar to the outer taper of the skirt portion the inner Walled surface is provided with a Luer taper which cooperates with the neck of a syringe barrel thereby to provide a friction mounting fit. This type of mounting is conventional and also, not particularly important to an understanding of the invention.

As best shown in FIG. 3 the neck portion of hub 10 is provided with a pair of diametrically opposed and equi distantly spaced ribs 22 and 26. The ribs are integrally formed on the hub structure and smoothly blend, as at 28 (FIG. 1), into the surface of skirt portion 16. The ribs are generally radially outwardly directed from the axis of the hub 10 and their peripheral surface is substantially straight thereby to define a cylindrical plane by rotating the hub about its axis. A second pair of ribs and 24 are equidistantly spaced from the first on the neck 18. The second pair of ribs may have their outer peripheries similarly formed and may be of an equivalent diameter. In FIG. 3 the outer diameter of ribs 20 and 24 is dimensioned slightly less than the dimension of ribs 22 and 26.

The shield member 12 is generally in the form of an elongated tube closed at one end 27 and opened at the other end 29. The opened end is formed With a flanged collar 30 which provides a surface that may be gripped when connecting the hub and shield members together. Internally of the collar are a plurality of vent passages 31 for the introduction of sterilizing gaseous mediums.

Additionally, for the purposes of gripping the shield member, a substantial portion of its body length is provided with serrations 32 that are spaced around the outer periphery. These serrations may be in the form of elevated or indented ribs and are disposed and displaced from one another by angles of, for example,

The shield may be of a plastic material, as discussed, and in the preferred embodiment is similarly formed from polypropylene.

Internally, the shield is provided With a plurality of longitudinally elongated ribs 34 which are generally radially inwardly directed. These ribs are, as shown in FIG. 3, disposed at angles removed from one another by approximately 90. As Will be explained in more detail below the ribs 34 and the ribs 2026 are capable of intercooperating once the hub and shield members have been coupled together.

A ring 36 is also formed internally of the shield member 12 as a unitary part thereof. From both FIGS. 1 and 2 the ring has an inwardly directed stepped surface leading to a flat planar level 38. Surface 38 has a diameter which is smaller than the outer diameter of both hub ribs 22 and 26. The surface, also, is smaller in diameter than the outer diameter of hub ribs 20 and 24 (see FIG. 3).

As a final point, a circumferential raised ring 40 is formed internally on the shield 12. Ring 40 determines the extent or limit of receipt upon coaxially mounting 4 the hub 10 and shield 12. This limit is determined by the abutting interaction of ring 40 and ribs 2026.

In summary, the present invention provides structure by which a tight interference fit may be obtained upon mounting a protective shield on a cannula supporting hub and maintained after sterilization and during subsequent marketing. Thus, the hub is provided with a plurality of ribs 20, 22, 24 and 26, each of which emanate from the skirt 16 and terminate adjacent the end of neck 18. As discussed, at least one pair of ribs ( ribs 22 and 26, see FIG. 3) are of a diameter which is greater than the internal diameter of surface 38. The diameter of ribs 20 and 24- may, as choice dictates, be similarly dimensioned.

Due to the unequal diameters, the shield, upon mounting, undergoes an outward fiexure in the area of the ring 36 as the slightly rounded forward rib structure traverses the stepped or gently sloping ring leading to the fiat surface 38. The shieid is longitudinally received to the point of abutment between the ribs and wall 40. When fully received the shield is effectively supported on the hub by the interference between two surfaces falling in a cylindrical plane and the radially inwardly directed recovery forces of the shield material. Upon partial recovery, during aging, the ring 36 actually creates slight rib indentations further aiding in the maintainence of a tight fit.

As discussed, each pair of ribs may or may not be of the same dimension. Obviously, if ribs 20 and 24 were enlarged a tighter fit would be obtained but, it has been found that an adequate and lasting engagement is provided with a structural interaction, as in FIG. 3. The prime function of ribs 2026 is, when the shield is mounted, to cooperate with shield ribs 34 to both provide interference and limit rotational movement. As is apparent the total number of ribs allow but a slight relative rotational movement between the hub and shield and thus, the latter may be used as a wrench when coupling the hub and cannula to the barrel of a hypodermic syringe.

From the foregoing it should be apparent that the ob jects and advantages of the invention are carried out. While the foregoing discussion is directed to a preferred embodiment of the device it is to be understood, however, that this is for the purpose .of description, only, since certain modifications may become evident to one skilled in the art which may be within the purview of the invention whose limits are defined by the appended claims.

Having described the invention, I claim:

1. In combination a rigid hub element having a longitudinal opening therethrough for receiving a needle cannula and being received on a barrel of a hypodermic syringe, said hub including a skirt portion and a neck portion of reduced diameter integral therewith and extending in opposite directions, said neck portion carrying at least one pair of diametrically opposed raised ribs longitudinally traversing substantially the entire neck length, said raised rib surfaces smoothly flowing from said skirt portion and formed such that all points on one rib surface are substantially equidistantly radially spaced from respective points on the other rib surface and lie on a cylindrical plane generated by revolving the hub about its axis said cylindrical plane having a diameter substantially equivalent to the diameter of the skirt portion in the vicinity of its junction with the neck portion, and a relatively less rigid elongated shield member adapted to be received on said hub thereby to completely enclose said needle cannula end, said shield being internally provided with a locking ring having an inner diameter which is smaller than the diameter of said generated cylindrical plane, said shield being axially received on said hub in a manner such that the interaction of the ribs and ring cause the relatively less rigid shield to ftex outwardly yet thereafter to partially recover its initial shape thereby to provide a tight fit in the area of interference between the ribs and ring.

2. The combination of claim 1 wherein said shield is provided with at least one pair of diametrically opposed and inwardly projecting ribs, said shield ribs being capable of cooperating with said hub ribs to substantially eliminate relative rotary movement in the assembled condition whereby said shield may function as a wrench when mounting said hub to said hypodermic syringe.

3. The combination of claim 1 wherein the inner surface of said shield opening is provided with a plurality of serrations thereby to allow access of sterilizing gases.

4. The combination of claim 1 further including abut- 10 References Cited UNITED STATES PATENTS 2/1962 Hamilton 20643 1/1965 Towns 2l547 WILLIAM T. DIXSON, JR., Primary Examiner.

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