US2229739A - Cartridge for hypodermic syringes - Google Patents

Description

1941- w. E. HARRINGTON 2,229,739

CARTRIDGE FOR HYPODERMIC SYRINGES Filed Nov. 10, 1938 MIN Patented Jan. 28, 1941 UNITED STATES PATENT OFFICE CARTRIDGE FOR HYPODERMIO SYRINGES William E. Harrington, Charleroix, Pa.

Application November 10, 1938, Serial No. 239,758

3 Claims. (Cl. 128-4872) My invention relates generally to hypodermic syringes and has particular reference to hypodermic syringes of the type employing a unitary dispensing cartridge as the medicament con- 5 tainer.

In the usual syringe of this type, the syringe proper includes a body portion adapted to removably receive the cartridge which contains the medicament or other liquid which is to be injected, a hollow double ended cannula or injection needle, and a plunger. The cartridge itself usually comprises a glass tube of suitable dimensions which is provided at one end with a stopper or plug closure which is adapted to be punctured I by the inner end of the injection needle and which is provided at the other end with a second stopper or plug which is adapted to be forced into the end of the tube by the plunger so as to act as a piston when the syringe is operated.

20 Heretofore considerable diiiiculty has been experienced in providing a stopper or plug closure for these cartridges which is readily pierceable by the inner end of the injection needle without resulting in leakage during use of the syringe.

2.3 Likewise, great difficulty has been experienced in the obtaining of a pierceable closure for cartridges of this type which can be easily and efiectively sterilized before they are pierced by the inner end of the injection needle. In fact, this 30 sterilization problem is so serious that some manufacturers market their product in hermetically sealed aseptic packages, despite the great cost and inconvenience of such procedures. 0f lesser importance, but still a troublesome problem to the 35 art, has been the provision of a cartridge of this type which possesses sumcient mechanical strength to withstand the rather large pressures frequently required duringthe operation of the syringe.

40 The principal object of my invention, therefore, is to provide an improved cartridge for use with hypodermic syringes of the above described type which shall be free from the disadvantages of the prior art devices, that is, which shall be provided 45 with closure means at the needle end which is not only readily pierceable by the inner end of the injection needle but which in addition is so arranged that eifective sterilization of the pierceable closure can be readily obtained. It is also 50 an object of my invention to provide an improved cartridge for hypodermic syringes which shall be capable of resisting much larger internal pressures than the cartridges of the prior art and to provide an improved cartridge for hypodermic 65 syringes in accordance with the above objects which shall be relatively inexpensive to manufacture and which at the same time shall be eflicient in operation.

The foregoing and other objects of my invention are achieved in part by the use of a cartridge 5 tube provided at one end with a beaded flange or tapered portion which restricts the central passageway in the tube so as to provide a centrally disposed aperture of substantially less cross sectional area than the cross sectional area of the tube, and in part by the use of a pierceable, soft rubber stopper or plug of particular design for closing and sealing the restricted end of the tube. This plug is securely held in the tube bythe beaded flange or tapered portion, and it may be provided at its outer end with a projection which extends into the restricted aperture at this end of the tube. The pierceable plug is also preferably provided with a recess at its inner end in order to facilitate the piercing of the stopper by the inner end of the injection needle and to form a sealing skirt on the plug which prevents leakage during the injecting operation.

As will be explained hereinafter in more detail, to make possible the efiective sterilizing of the pierceable end closure prior to use of the cartridge, the plug at the restricted end is provided with a disc of metal foil which is preferably permanently attached thereto and which covers at least that portion of the plug which is exposed by the aperture in the end of the tube.

In the preferred form of the invention, this permanent attachment is obtained by vulcanizing or cementing the disc to the sealing plug.

The present application is a continuation in part of my co-pending application Serial No. 93,223 which was filed on July 29, 1936.

Referring to the drawing wherein I have illustrated and described certain preferred forms of my invention:

Figure 1 is a longitudinal cross sectional view on an enlarged scale through a hypodermic cartridge embodying the principles of my invention;

Figure 2 is a perspective view of the pierceable stopper or plug forming a part of the cartridge indicated in Figure 1;

Figure 3 is a fragmentary perspective view showing a second form of pierceable stopper or plug in accordance with my invention and a fragmentary portion of the adjacent tube wall;

Figure 4 is a perspective view similar to Figure 3 showing a third form of pierceable stopper or plug in accordance with my invention;

Figure 5 is a fragmentary sectional view similar to the upper portion of Figure 1 and illustrates a further form of my invention; and

Figure 6 is a view similar to Figure 5 illustrating still another form of the invention.

In the cartridge illustrated in Figure 1 of the drawing, the cylindrical tube which is adapted to receive the liquid medicament is indicated at II. This tube is preferably made of glass and in the most common type of cartridge used today is about three inches long, having an inside diameter of about V of an inch and an outside diameter of about of an inch. The needle end of the tube may be restricted in various ways, but I prefer to form thereon a beaded flange such as is illustrated at ii in Figure 1 by rotating the tube while it is exposed to a suitable flame. The beaded flange l3 made by this operation will extend substantially at right angles to the longitudinal axis of the tube and may conveniently be extended to restrict the circular, needle-receiving aperture l5 to the desired size. For most satisfactory results, however, the diameter of this aperture l5 should not be smaller than about the internal diameter of the tube and should not be greater than about the internal diameter of the tube.

The restricted end of the tube II is sealed by a pierceable plug illustrated at II, which plug is ordinarily made of relatively soft and flexible rubber. The plug isof cylindrical shape, as illustrated in Figure 2, and in the preferred form of the invention is provided with a cylindrical projection I! which extends into the needlereceiving aperture l5 at the restricted end of the tube II. The plug I1 is also provided with a recess II of fairly large dimensions extending into the body thereof from the end opposite the projection l9. This recess 2| reduces the thickness of the plug which has to be pierced by the inner end of the injection needle, and also provides a circumferentially extending sealing skirt which aids in eifecting a good hydraulic seal between the plug l1 and the walls of the tube ll during the injecting operation.

The upper surface of the projection is which extends into the needle-receiving aperture l5 at the restricted end of the tube H is covered with a foil disc 23, as illustrated in Figures 1 and 2. This foil disc 23 is permanently attached to the underlying projection l9, preferably by being vulcanized or cemented directly thereto, and to aid in obtaining this attachment, the disc may be provided with a series of projections which extend inwardly into the plug as indicated at 25. These projections 25 are not essential but are of aid in accomplishing a securepermanent attachment of the disc 23 to the plug body. I

The other end of the tube II is closed by a cylindrical rubber plug 25 of the conventional type which serves as a piston during the injecting operation. It is desirable that this piston member shall be provided with one or more circumferentially extending grooves such as a e indicated at 21 to aid in obtaining a liquid tight seal.

The closure plug 29 illustrated in Figure 3 is similar in form to the plug I1 illustrated in Figures 1 and 2, except that the foil disc 3| attached to the projection 33 of this plug is of such size as to not only completely cover the top of the projection 33, but in addition to extend beneath the edge of the beaded flange I! of the tube II. This type of foil construction has been found in certain instances to be somewhat easier to sterilize than the construction of Figure 1. Also, the foil II in this form is held in place between the plug and the wall of the bead. The plug 20, of course, includes a recess at its inner end similartotherecessll.

In Figure 4 I have illustrated another form of pierceable plug construction. In this form, the outer end of the plug illustrated at 35 has been molded flat and provided with a foil disc fl of somewhat greater diameter than the diameter of the aperture l I at the restricted and of the tube II. This form of plug is also suitable for use in conjunction with a cartridge tube having a tapered end such as is illustrated at 39 in Figure 6, and while this is not the preferred form of the invention, it does possess some advantages over the prior art arrangements.

The distortion of the plug 35 incident to its being forced into the tapered end 33 of. the cartridge tube will cause it to assume the shape illustrated in Figure 6, and it is desirable in a construction of this type that the foil disc 31 shall be atleast as large as the aperture at the tapered end of the tube. Also, anchoring projections as illustrated at II are particularly desirable in this tapered end construction. The plug 35 also has a recess 2| for providing a sealing skirt.

In Figure 5 I have illustrated the needle end portion of a cartridge tube which is provided with both a tapered portion 43 and with a right angle flanged bead 45. The pierceable sealing plug 41 of the Figure 5 construction is substantially identical with the plug ll except that the foil disc 49 used with the plug 41 is of greater diameter than the internal diameter of the tube and is adapted to be held in place by the normal pressure existing between the inside walls of the tube and the plug itself. When utilizing a disc of this type which extends between the flange and the plug, it is usually unnecessary to vulcanize or cement the foil to the plug.

If desired, any of the plugs I1, 29, 35, or ll may be provided with circumferentially extending grooves such as are illustrated at 5| in Figure 5 to assist in sealing the plug in the tube.

Before cartridges of this general type are used, it is practically the universal practice to sterilize the pierceable-end thereof. While dipping this end in alcohol or some other antiseptic is of some value, such procedures do not produce near- 1y so effective a sterilization as can be obtained by flaming, i. e. by placing the end of the tube in a gas or alcohol flame. Many of the prior art cartridges could not be flamed, but extensive tests have established that each of the various types of plug closures described above can be flamed with excellent results, for the reason that the metal disc provided at the end of the pierceable plug protects the plug from injury during flaming, while at the same time Providing an impervious exposed medium. The construction is free from; the disadvantages of'prior art devices utilizing metallic ends, which could be flamed, in that the foildisc can readily be made thin enough to permit ready piercing thereof by the inner end of the injection needle. Also, because of this ease in piercing the stopper of my invention, there is little, if any, tendency for the stopper to become displaced during the piercing operation.

The right angle beaded flange construction which is the preferred form of the invention has been found to provide a positive seal at the needle end of the cartridge which definitely prevents sembly of the cartridge. During the sterilizing of the stoppers prior to the filling of the cartridges,

they are subjected to considerable mechanical handling, and in the absence of a vulcanized or cemented connection, it is diflicult to assemble structures of the type illustrated in the constructions of Figures 3 and 4. It will be understood,

however, that from a purely mechanical view-- point discs such as are illustrated in Figures 3, 4, and 5 may be held in place in the finished cartridge solely by the friction resulting from the pressure engagement of the rubber plug against the beaded flange.

While several forms of the invention have been illustrated and described herein, it will be apparent to those skilled in the art that various other forms of cartridges may be constructed in accordance with the principles which I have disclosed in the foregoing. It is my desire, therefore, that the accompanying claims shall be accorded the broadest reasonable construction consistent with the language appearing therein and the prior art.

I claim the following as my invention:

1. A cartridge for liquid medicament comprising a hollow glass tube, one end of the. tube tapering inwardly to reduce the tube diameter, the tapered tube end terminating in a flange extending substantially at right angles to the axis of the tube and defining an aperture less than about half of the diameter of the tube,-a soft rubber plug in the tapered tube end, a cylindrical projection on the plug extending into the aperture at the end of the tube to substantially fill the space encompassed by said flange, said plug The vulcanizing or having a cylindrical recess in' its end opposite the projection and forming a sealing skirton the plug, a thin disc of metal foil of greater diameter than the. inside of the tube positioned over the end of the plug and held between the plug and 5 the tube, and a rubber sealing piston adapted to have a-close sliding fit with the tube positioned in and closing the other end of the tube.

2. A container for liquid medicament comprising a hollow tube, the tube end terminating in a flange extending substantially at right angles to the axis of the tube and defining an aperture less than the diameter of the tube, a soft rubber plug in the flanged tube end, a cylindrical projection of the plug extending into the aperture to substan- 15 tially fill the space encompassed by said flange at the end of the tube, a thin disc of metal foil of greater diameter than the" inside of the tube positioned over the end of the plug and held between the plug and the tube, and a rubber sealing 20 piston adapted to have a close sliding flt with the tube positioned in and closing the other end of tending into saidaperture to substantially fill the space encompassed by said flange and having a recess at its inner end which provides a sealing g5 skirt on said plug. fixedly supported, thin tyvmum a. narmmcirou.

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