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Publication numberUS1935494 A
Publication typeGrant
Publication dateNov 14, 1933
Filing dateMar 20, 1930
Priority dateMar 20, 1930
Publication numberUS 1935494 A, US 1935494A, US-A-1935494, US1935494 A, US1935494A
InventorsWest Herman O
Original AssigneeWest Herman O
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Plunger for hypodermic syringes and the like
US 1935494 A
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Description  (OCR text may contain errors)



-- Herman West, Philadelphia, Pad Application M crame. Serial News); 1 Claim. '(Cl. 128-218) This invention relates primarily to improve- Fig. 3' ,is a view in perspective illustrating a ments in hypodermic syringesand more particufurther step in the process of manufacture; larly toimprovements in the rubber plungers Fig. 4 shows a sectional View of the finished which constitute a standard part of such devices. p unger, and

5 In hypodermic syringes it is frequently desir- Figs. 5'and 6 are sectional views illustrating a v able to retract as well as advance the plunger in modification within the scope of the invention.

the syringe cylinder, and for this purpose the In the production of a socket member'in acplungers, commonly of flexible rubber, are cordance with my invention, I prefer to employ equipped with inserted sockets threaded or a blank in theform ofa rod 1 of square cross .10 otherwise formed for interlocking connection section which may be of brass or other suitable with a stem by means of which the plunger may material. In an initial operation, I mayemploy be actuated. Considerable difiiculty. has been a rotary boring tool, as indicated at '2 in Figs. 1 experienced in obtaining an eficient bondbeand 2, which is adapted t Simultaneously O m tween the rubber of the plunger and the socket in the end of the blank 1 a central lon itud al '15 element, and particularly in the retracting of the Cylindrical recess 3 and an outer Co plunger, the socket elements have been s bject nular recess 4, the latter intersecting the sidev to breaking away from the rubber plunger, surfaces of the blank to form spaced ears or prothereby rendering the syringe inoperative. The J'ec O S ab y and s st at d, the difficulty is increased by the fact that frequently portions of the cutter 2 which form the recess 4 12 0 the plungers stick in the barrel and can be are flared or beveled outwardly a v the Cutting released only by rotating the plunger, a moveedge whereby as the cutter advances in the ment which tends to tear the socket loose from cutting ope the ears P j i 5 are the rubber. Another influencing factor resides b nt' u w y awa from e al y nd ical in the fact that the syringe, after being charged p 6, as Clearly illustrated- FOllOWihg the d 1 25 with serum or other substance is usually subing or boring op n as set forth abov h so jected to a sterilizing operation at a, relatively socket element is completed y internally hreadhigh temperature, .this heat effecting chemical in o tapp t c cylindricaliopening 3 changes tending to separate the rubber from the and by cutting w y the machined extremity of a socket 1ement nd tending l t Cause th the blank 1 to obtain an element substantially as 1-30 rubber plunger to adhere to the sides of the illustrated in The socket member thus cylinder. produced'is introduced into the mold in which Y It is an object of thisihvention to provide an the rubb r plu 715 rm d a d isjmelded into improved plunger having astem-receiving socket e pl W known n r, the fi s ed j so formed and embedded in the plunger as. to art being Shown i Fig;

-':35 effectively resist the tendency of all normal Socket-member 0f t o m illu trated and 549 of separation of the socket member and consestrains and stresses to loosen the socket from described above has been found admira y u ed the surrounding rubber, and thereby to provide for the Q P The base hortlon 0f t mema plunger t may be freely advanced or ber, proJectmg from the sides of the central tracted or rotated in the cylinder without danger socketed part establishes relatively extended rubber-abutted surfaces which are normal to the thrusts or strains exerted through the stem 8 1 I. 'ther advancing or retracting the plunger in The invention resides not only 1n the plunger I as a whole but in the specific form andmethod of barrel the Syringe i are Capable of l manufacture of the socket insert as hereinafter Standing t e forces tendmg toward Separatlon Set forth of. the socket member from the rubber. In the i th tt h d d V retraction movement the tongues 5-also assist in e i awm anchoring the socket member, and these elements streamers retreatin r of member 0 ear oose rom e rubber w en the cedure the socket member is manufactured, and plunger through t te 3 is tat i th 5, also sh ws a p o of one r of tool that y barrel. This function of the tongues 5 is aided be e p y by the flared formation previously described. Flg. 2 is a View in perspective illustrating the It will be noted that but three operations are initial step in the manufacture of the socket required for producing the socket member in the quent destruction of the syringe.

}55 member; procedure outlined above,-and while. a socketmember embodying the substantially same desirable characteristics may be produced by other methods, the one herein described commends itself for its simplicity and relative cheapness. It has also been found that with a tool of the general character illustrated, the longitudinal edges of the tongues 5 are rough and uneven which aids in creating a firm bond between these elements and the rubber of the plunger.

In Figures 5 and 6, I disclose a socket-member formed of metal tubing. In this instance a blank tube is internally threaded at one end and at the other end is divided longitudinally by crosscuts to form four sections which are then bent outwardly and back to form elements corresponding to the tongues 5 of the previously described embodiment. The corresponding parts of V the two embodiments are identified by the same reference numerals.

I claim:

A plunger for hypodermic syringes comprising a cylindrical body portion, and an integral socket member embedded in said body portion, said socket member comprising a base and a central socket for the reception of an actuating stem, a substantially rectangular flange on the socket member projecting from the base in the plane thereof, and an element at each corner of said flange extending laterally therefrom along the socket portion substantially parallel therewith and spaced therefrom whereby rotational, lateral and axial movements of the socket member within the body portionare prevented.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2592381 *Oct 13, 1949Apr 8, 1952Premo Pharmaceutical Lab IncHypodermic syringe
US3751795 *Feb 8, 1972Aug 14, 1973Favre HMethod of making bezels for setting precious stones
US6318221 *Apr 4, 2000Nov 20, 2001Hydra-Seal, Inc.Apparatus and method for forming sealing rings
US8206353Aug 25, 2009Jun 26, 2012Medtronic Minimed, Inc.Reservoir barrier layer systems and methods
US8702655Apr 19, 2011Apr 22, 2014Medtronic Minimed, Inc.Reservoir barrier layer systems and methods
WO2009126596A2 *Apr 7, 2009Oct 15, 2009Medtronic Minimed, Inc.Reservoir plunger head systems and methods
U.S. Classification604/218, 29/558, 29/417, 82/1.11
International ClassificationA61M5/315
Cooperative ClassificationA61M5/31511, A61M5/31515
European ClassificationA61M5/315C