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Publication numberUS1961023 A
Publication typeGrant
Publication dateMay 29, 1934
Filing dateDec 7, 1933
Priority dateDec 7, 1933
Publication numberUS 1961023 A, US 1961023A, US-A-1961023, US1961023 A, US1961023A
InventorsHerman O West
Original AssigneeHerman O West
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Plunger for hypodermic syringes
US 1961023 A
Abstract  available in
Images(1)
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Claims  available in
Description  (OCR text may contain errors)

May 29, 1934. H. 0. WEST PLUNGER FOR HYPODERMIC SYRINGES Filed Dec. 7, 1933 Patented May 29, 1934 UNITED STATES PATENT OFFICE Claims.

This invention relates to improvements in rubber plungers of the type employed in hypodermic syringes. To facilitate movement of these plungers in their cylinders, it has been proposed to 5 incorporate a lubricant such as paraffin in the rubber composition, and it is common practice for the same purpose to provide the plungers with circumferential grooves for reception of a lubricating medium such as glycerine. When pressure is applied to plungers of this class, and particularly those having an incorporated lubricant, there frequently occurs a leakage of the liquid contents of the cylinder past the sides of the plunger, and I have discovered that this leakage is due to a cooking or angular displacement of the plunger in the cylinder and a resultant bypassing of the liquid through the aforesaid circumferential groove to the rear of the plunger. The principal object of the present invention is to provide a plunger of the stated character which while having the desirable lubricating features shall be constructed as to prevent bypass ing of the liquid past the plunger in the manner previously described.

In the attached drawing:

Figure 1 is a fragmentary sectional view of a cylindrical container adapted for use in a certain type of hypodermic syringe, a portion of the latter being shown in broken lines;

Fig. 2 is a view in perspective of a plunger made in accordance with my invention, and

Fig. 3 is a view in perspective of a modified form of plunger within the scope of my invention.

3 With reference to the drawing, 1 is a glass or other cylinder forming the body of the container. One end of this cylinder is closed by a rubber stopper 2, and in the opposite end is a plunger 3 adapted to slide in the cylinder to expel the liquid contents normally confined between the stopper 2 and the plunger 3. Containers of this type are adapted for use with hypodermic syringes comprising a casing or body portion 4 adapted to receive the container 1, and a double-ended needle 5 the inner end of which projects into the chamber of the casing 4, so that when the container 1 is inserted this end of the needle penetrates the stopper 2. At the opposite end of the casing 4 is slidably mounted a 50 plunger rod 6 through which pressure may be applied to the outer face of the plunger 3, as illustrated, to force the plunger toward the stopper 2, and to thereby eject the contents of the container through the needle 5. In this type of syringe, the plunger rod 6, by reason of its relatively loose mounting, is subject to displacement with respect to the axis of the container 1, and may thus come to bear against the plunger 3 adjacent the edge of the latter as illustrated. Under these conditions there is a tendency for the plunger to become displaced angularly in the cylinder as illustrated, and when the plunger is provided with a continuous circumferential groove, this groove forms a bypass channel through which the liquid contents of the container 1 are permitted to escape. This tendency to angular displacement of the plunger is particularly pronounced in plungers having an incorporated lubricant such as paraffin, as previously set forth.

In accordance with my invention, I may provide the plunger 3 in lieu of the continuous circumferential groove with an interrupted circumferential groove, such for example as illustrated at '7 in Figs. 1 and 2. The sections of this interrupted groove are separated by webs 8, the outer faces of which preferably lie flush with the cylindrical surface of the plunger. This interrupted groove provides the desirable recess for reception of the lubricant, but effectively prevents bypassing of the liquid contents of the container with which it is associated.

It is apparent that my invention in principle may find various embodiments, such for example as that illustrated in Fig. 3, wherein the cylindrical surface of the plunger is provided with a plurality of pits or recesses 9 arranged in one or more series extending around the circumference of the plunger. These recesses constitute pockets for the lubricant, which is desirable, but avoids the undesirable feature of the continuous circumferential recess, which as previously set forth is responsible under certain conditions for the escape of the contents of the syringe.

There may be other modifications without departure from the invention.

I claim:

1. A plunger of the type set forth consisting of a resilient substantially cylindrical body having in the side a plurality of recesses extending in a disconnected series around the circumference of the plunger.

2. A plunger of the type set forth consisting of a resilient substantially cylindrical body having in the side a plurality of circumferentially spaced recesses.

3. A plunger of the type set forth consisting of a resilient substantially cylindrical body of rubber having in the side thereof a plurality of circumferentially spaced recesses.

4. A flexible cylindrical plunger of the type set forth having in the side thereof a plurality of lubricant receiving circumferentially spaced recesses.

5. A plunger of the type set forth consisting of a resilient substantially cylindrical body of a rubber composition containing a lubricating constituent, said body having in the side thereof a plurality of circumferentially spaced recesses.

HERMAN 0. WEST.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2531667 *Dec 1, 1947Nov 28, 1950Brent Bernard JMethod of and apparatus for administering repeated injections
US2591046 *Oct 18, 1948Apr 1, 1952Frederick M TurnbullHypodermic syringe assembly
US2832340 *Mar 26, 1957Apr 29, 1958American Home ProdSyringe push rod
US4299238 *Jun 24, 1980Nov 10, 1981Baidwan Balinderjeet SVented piston and push-rod subassembly for use in a syringe barrel
US5586975 *Dec 29, 1994Dec 24, 1996Takeda Chemical Industries. Ltd.Air and liquid tight container with a slidable gasket
US5605542 *Nov 14, 1995Feb 25, 1997Takeda Chemical Industries, Ltd.Prefilled syringe
US5716339 *Sep 19, 1995Feb 10, 1998Takeda Chemical Industries, Ltd.Prefilled syringe
US5817056 *Sep 11, 1996Oct 6, 1998Takeda Chemical Industries, Ltd.Prefilled syringe
US5865799 *Jul 23, 1997Feb 2, 1999Takeda Chemical IndustriesPrefilled syringe
US8002734Aug 23, 2011Boehringer Ingelheim International GmbhDual chamber container and process for its filling up
US8096971Jan 17, 2012Boehringer Ingelheim International GmbhDual chamber container for lyophilization, process for the filling up and use thereof
US8747356Nov 19, 2008Jun 10, 2014Mallinckrodt LlcFluid delivery system with multi-dose fluid source
US20070060877 *Aug 14, 2006Mar 15, 2007Stefan BassarabDual chamber container for lyophilization, process for the filling up and use thereof
US20070129673 *Aug 14, 2006Jun 7, 2007Stefan BassarabDual chamber container and process for its filling up
US20090285453 *Nov 19, 2009Muquit Mohammad AbdulAuthentication device, authentication method, registration device and registration method
US20100249586 *Nov 19, 2008Sep 30, 2010Cocker Robin CFluid Delivery System with Multi-Dose Fluid Source
US20130134188 *Apr 21, 2011May 30, 2013Yoshino Kogyosho Co., Ltd.Cartridge-type dispenser
EP0568321A2 *Apr 27, 1993Nov 3, 1993Takeda Chemical Industries, Ltd.Prefilled syringe
WO2003051434A2 *Dec 11, 2002Jun 26, 2003Disetronic Licensing AgAdministration device comprising an expulsion member and a stopper covering
WO2003051434A3 *Dec 11, 2002Oct 30, 2003Disetronic Licensing AgAdministration device comprising an expulsion member and a stopper covering
WO2009067200A2 *Nov 19, 2008May 28, 2009Mallinckrodt Inc.Fluid delivery system with multi-dose fluid source
WO2009067200A3 *Nov 19, 2008Sep 24, 2009Mallinckrodt Inc.Fluid delivery system with multi-dose fluid source
Classifications
U.S. Classification604/230
International ClassificationA61M5/24, A61M5/315
Cooperative ClassificationA61M2005/247, A61M5/24, A61M5/31513
European ClassificationA61M5/315C1, A61M5/24