US2813528A - Hypodermic syringe - Google Patents

Description

Nov. 19, 1957 s. N. BLACKMAN HYPODERMIC SYRINGE Filed Feb. 13. 1956 .HWVENTOR.

WWWAEKS United States Patent HYPODERMIC SYRINGE Seymour N. Blackman, Teaneck, N. J., assignor to Omega Precision Medical Instrument Co., Inc., Passaic, N. J., a corporation of New Jersey Application February 13, 1956, Serial No. 564,954 4 Claims. (Cl. 128-218) This invention relates to a hypodermic syringe.

More particularly my invention pertains to that type of hypodermic syringe in which an open ended glass sleeve constitutes the syringe barrel and is received in a body which carries the syringe tip.

Syringes of the foregoing type are preferred over conventional syringes which constitute an all-glass body wherein the syringe barrel is in one piece with the body, inasmuch as all-glass syringe bodies are difiioult to internally form to the close tolerances required for maintaining pressure under the plunger during injection. It is a considerable advantage to be able to form the barrel in a glass tubing machine where the glass sleeve can be held to close tolerances at comparatively small cost. However, until the present time, no construction has been proposed which can compete commercially with a standard all-glass syringe body. Either the proposed constructions are too elaborate, too diflicult to assemble and take apart, too ditficult to make, too difiicult to clean or too expensive.

It is an object of my invention to provide a hypodermic syringe of the character described which is not subject to any of the foregoing disadvantages and which will be able to compete commercially with a presentday all-glass hypodermic syringe. i It is another object of my invention to provide a syringe of the character described which constitutes but two parts in addition to the insertable glass sleeve, in which the construction is such that the sleeve can either be inserted or removed with great ease, in which the sleeve does not have to be specially positioned for insertion and in any position thereof in the body will form an excellent seal therewith, in which the body parts are of very simple construction and are made in an inexpensive fashion that lends itself to mass production, and in which the parts can be easily disassembled for cleaning and sterilization.

It is another object of my invention to provide a hypodermic syringe of the character described which readily can be fabricated by injection molding whereby the cost can be reduced to a very low figure.

Other objects of my invention in part will be obvious and in part will be pointed out hereinafter.

My invention accordingly consists in the features of construction, combinations of elements and arrangement of parts which will be exemplified in the hypodermic syringe hereinafter described and of which the scope of application will be indicated in the appended claims.

Inthe accompanying drawings in which is shown one of the various possible embodiments of my invention,

Fig. 1 is a front view of a hypodermic syringe constructed in accordance with my invention;

Fig. 2 is an enlarged longitudinal sectional view therethrough taken substantially along the line 2-2 of Fig. 1;

Fig. 3 is an exploded view of the syringe; and

Figs. 4 and 5 are sectional views taken substantially along the lines 44 and 5-5 respectively of Fig. 2.

Referring now in detail to the drawings, the reference numeral 10 denotes a hypodermic syringe embodying my invention and constituting a body 12 and sleeve 14. The sleeve is made of glass such as is commonly utilized in hypodermic syringes, i. e., glass which can be sterilized at the temperatures commonly employed for this purpose, e. g., C., without suffering any noticeable temperature deformation or deterioration. Sleeving of this type with an inner diameter accurate to the small tolerances necessary in syringes is commercially available at a price which is low compared with the price of a ground one-piece syringe barrel.

The length of the sleeve need not be highly accurate for a reason which soon will be apparent. Particular attention is directed to the fact that the ends of the tube are simply flat cut. No special shape is imparted to either end, even to the forward end 16, and it is not essential although it is desirable that said ends be cleanly cut. Nor is it necessary for either end to be ground.

The body 12 is tubular in shape and is fabricated from material which is somewhat soft so that it can bend and yield locally under strain but sufficiently rigid so as not to stretch unduly upon subjection to stresses such as will be incurred in a structure of the type hereinafter described and not to become misshapen or warped by such stresses. Moreover, the material must not be deformable at sterilizing temperatures, e. g., temperatures of the order of 120 C. Furthermore, the material must be chemically inert to all substances that properly may contact a hypodermic syringe. In addition, pursuant to an ancillary feature of my invention, I prefer to utilize for the body a material which can be formed by injection molding, i. e., a thermoplastic synthetic resin. Typical materials which possess all of the foregoing characteristics are nylon, a polyamide synthetic resin, and vinyl copolymers.

The body is molded in one piece from nylon with two diametrically opposite, oblong, longitudinally extending openings 18 in the wall thereof. The purpose of said openings is to permit the sleeve which may carry graduations and the like to be visible.

The forward end 19 of the body 12 is closed by a bottom 20 including a forwardly projecting Luer tip 22 joined to said bottom by a neck 24 of reduced diameter. A bore 26 extends through said bottom, neck and tip to provide an exit from the inside of the syringe. The inner diameter of the body is just slightly larger than the external diameter of the sleeve whereby the sleeve is a snug fit in the body.

The rear end 28 of the body 12 is formed with an external thread to receive an internally threaded hex-agon-al cap 30. The crown 32 of the cap is formed with a large central opening 34 the diameter of which is greater than the inner diameter of the sleeve but lesser than the external diameter of the sleeve. Thus, when the cap is screwed on the body, the crown extends over the rear end 35 of the sleeve but not over its bore.

When the forward end of the sleeve is seated against the rear surface of the bottom 20, the rear end of the sleeve protrudes from the rear end of the body. Thus, when the cap is screwed on the body, the body and cap are placed under tension, and, in effect, the bottom 20 of the body is pulled against the forward end 16 of the sleeve. Since the body is of nylon, and, accordingly, is somewhat soft, the forward end 16 will be slightly embedded in said rear surface, producing thereby a fluidtight seal. Said forward end of the sleeve will be embedded to an extent sufiicient to create the desired seal even if said end is not ground. Thus, although the sleeve is only flat cut at its ends, a proper seal will be provided according to the present invention, and the need for expensive grinding steps is eliminated. Also, the length of the sleeve need not be critically controlled so long the contours of the ragged edge after which the edge is effectively embedded in the Wall.

A conventional plunger 36 adapted to be snugly slidably received in the sleeve is provided. Said plunger is longer than the sleeve, and its handle end 38 extends above the same when the plunger is fully inserted in 7 the sleeve.

The syringe produced according to the present invention has all the attributes of metallic syringes and finely ground glass syringes with none of their disadvantages.

Moreover, the present syringe is less expensive to manufacture than conventional syringes since it employs less expensive materials and avoids the steps of manufacture requiring high skill and expensive machines.

It thus will be seen that I have provided a device which achieves all the objects of my invention and is well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiment above set forth, it is to be understood that all matter herein described, or shown in the accompanying drawing, is to be interpreted as illustrative and not in a limiting sense.

Having thus described the invention, there is claimed as new and desired to be secured by Letters Patent:

1. In a hypodermic syringe, a tubular body, an openended glass sleeve having a tubular bore adapted to slidably receive a plunger, and a closure member, said body being fabricated from a yieldable synthetic plastic, a forward end and an open rear end on said body, a bottom closing said forward end, said rear end being closed by said closure member, said body having a bore extending through said bottom to provide an exit from the inside of the syringe, the inner diameter of the body being slightly larger than the external diameter of the sleeve whereby it is adapted to receive the sleeve, said closure member bearing against the rear end of the sleeve and the forward end of the sleeve bearing against said bottom, said closure member and body having cooperating means urging the sleeve axially towards said bottom of the body on rotation of the closure member whereby on such rotation of the closure member a fluid-tight seal is formed between said bottom and the forward end of the sleeve.

2. In a hypodermic syringe, a tubular body, an openended glass sleeve having a tubular bore adapted to slidably receive a plunger, and a closure member, said body being fabricated from a yieldable synthetic plastic, a forward end and an open rear end on said body, a bottom closing said forward end, said rear end being closed by said closure member, a tip projecting forwardly from said bottom, said body having a bore extending through said bottom and tip to provide an exit from the inside of the syringe, the inner diameter of the body being slightly larger than the external diameter of the sleeve whereby it is adapted to receive the sleeve, said closure member bearing against the rear end of the sleeve and the forward end of the sleeve bearing against said bottom, said closure member and body having cooperating means urging the sleeve axially towards said bottom of the body on rotation of the closure member whereby on such rotation of the closure member a fluid-tight seal is formed between said bottom and the forward end of the sleeve.

3. In a hypodermic syringe: a tubular body, an openended glass sleeve having a tubular bore therein adapted to snugly receive a plunger, and a cap, said body being fabricated from a yieldable synthetic plastic, a forward end and a rear end on said body, a bottom closing said forward end, a tip projecting forwardly from said bottom, said body having a bore extending through said bottom and tip to provide an exit from the inside of the syringe, the inner diameter of the body being slightly larger than the external diameter of the sleeve whereby it is adapted to snugly receive the sleeve, the rear end of the body including an external thread, the cap having an internal thread and being adapted to screw onto the thread at the rear end of the body, said cap including a crown having a large central opening, the diameter of said opening being greater than the inner diameter of the sleeve but lesser than the external diameter of the sleeve whereby when the cap is screwed onto the body the crown extends over the rear end of the sleeve but not over the bore thereof, the sleeve being longer than the distance between the rear surface of the bottom and the rear end of the body so that when the cap is screwed onto the body said rear surface of the bottom is pulled against the forward end of the sleeve to form a fluidtight seal between the bottom and the forward end of the sleeve.

4. In a hypodermic syringe: a tubular body, an openended glass sleeve having a tubular bore therein adapted to snugly receive a plunger, and a cap, said body being fabricated from a yieldable synthetic plastic, a forward end and a rear end on said body, a bottom closing said forward end, a tip projecting forwardly from said bottorn, said body having a bore extending through said bottom and tip to provide an exit from the inside of the syringe, the inner diameter of the body being slightly larger than the external diameter of the sleeve whereby it is adapted to snugly receive the sleeve, the rear end of the body including an external thread, the cap having an internal thread and being adapted to screw onto the thread at the rear end of the body, said cap including ,a crown having a large central opening, the diameter of said opening being greater than the inner diameter of the sleeve but lesser than the external diameter of the sleeve whereby when the cap is screwed onto the body the crown extends over the rear end of the sleeve but not over the bore thereof, the sleeve being longer than the distance between the rear surface of the bottom and the rear end of the body so that when the cap is screwed onto the body said rear surface of the bottom is pulled against the forward end of the sleeve to for a fluid-tight seal between the bottom and the forward end of the sleeve, said body having an oblong longitudinal opening therein.

References Cited in the file of this patent UNITED STATES PATENTS 679,198 Witkowski July 23, 1901 1,471,644 Bandman Oct. 23, 1923 2,409,656 Austin Oct. 22, 1946 2,545,017 Billingsley Mar. 13, 1951 2,574,964 Eisenstark Nov. 13, 1951 2,699,168 Lewis Jan. 11, 1955

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