US2771880A - Syringes - Google Patents

Description

Nev. 27, 1956 F. GOTTHART SYRINGETS Filed Jan. 13, 1953 IN V EN TOR.

Bed Gall/W2 ATZURME'KS' SYRINGES Fred Gotthart, Ridgewood, N. Y.

Application January 13, 1953, Serial No. 331,029

8 Claims. (Cl. 128-218) The present invention pertains to medical syringes and more particularly to syringes of this character suitable for use in the subcutaneous injection of medication or in the aspiration or withdrawal of a body fluid such as blood for laboratory examination.

Syringes of the general type here involved are presently made, which comprise a barrel of glass or similar material with a closely fitting piston slidably disposed within the barrel. The sealing means relied upon to prevent leakage from the barrel past the piston has heretofore been an accurately ground fit between the inside walls of the barrel and the external walls of the cylindrical piston. In spite of this close fit fluid can penetrate into the highly restricted space between the internal wall of the barrel and the external wall of the piston. This liquid will frequently tend to harden or to coagulate, interfering with the operation of the syringe.

It is among the objects of the present invention to avoid this difiiculty by the use of a form of construction in which the plunger fits loosely Within the barrel, there being an appreciable clearance provided between the external surface of the plunger and the inside wall of the barrel.

An object of the invention is to provide a syringe comprising a hollow cylindrical barrel and a loosely fitting cylindrical piston freely slidably disposed within the barrel, a resilient sealing member being fixed to the barrel. The resilient sealing member comprises a lip portion which surrounds the piston and engages the piston laterally, the lip portion being so arranged that its lateral sealing pressure against the piston increases with an increase in pressure differential between the liquid pressure within the barrel and the atmospheric pressure external to the barrel.

A further object of the invention is to provide a syringe with a loosely fitting plunger which includes simple and easily sterilized resilient sealing means for preventing the leakage of liquid along the plunger and out of the barrel.

Another object of the invention is to provide a sealing means of this character which is eifective for barrel pressures both above atmospheric pressure and below atmospheric pressure, thus permitting the syringe to be used both for the injection and the withdrawal of or aspiration of liquids.

Still another object of the invention is the provision of means for preventing the syringe from rolling when resting on a flat surface.

A further object of the invention is the provision of means for making the entire syringe easy to disassemble and reassemble in order to facilitate its cleaning and sterilization.

Still another object of the invention is to provide a resilient seal which will adapt itself to small differences in form of the plunger by eliminating costly precision grinding work of barrel and piston, thus making it simple and economical to manufacture the syringe.

Other and further objects will become apparent upon rates Patent reading the following specification together with the accompanying drawing forming a part hereof.

Referring to the drawing:

Figure 1 is a sectional view in elevation of an em bodiment of the invention;

Figure 2 is a fragmentary sectional view in elevation of the embodiment of Figure 1, showing the plunger removed from the barrel;

Figure 3 is a fragmentary sectional view in elevation showing a modified form of the invention;

Figure 4 is a fragmentary sectional view in elevation showing a further modified form of the invention;

Figure 5 is a plan view of the embodiment shown in Figure 4;

Figure 6 is a plan view of an anti-rolling device in unfolded condition; and

Figure 7 is a side view of the anti-rolling device of Figure 6 in folded condition ready to be applied to the syringe.

Referring to Figure l, the syringe comprises a barrel 11 having a lower shank portion 12 adapted to receive a needle which has been omitted from the drawing for simplicity of illustration. The needle is the usual hollow needle and when attached to the syringe communicates with the interior of the barrel 11 through the passage 13.

Disposed within the barrel 11 is a loosely fitting piston or plunger 14 which terminates at its upper end in an enlarged head 15 connected to the piston 14 by a shank portion of reduced diameter 16.

At its upper end, the barrel 11 terminates in an out wardly flaring lip 17. Pressed against the upper surface of the lip 17 is a sealing device or washer 18 formed of resilient material resistant to heat and to a wide variety of chemicals and solvents, such as neoprene, for example. The sealing means 18 has a radially outwardly projecting flange portion 19 which is held against the outwardly flaring lip 17 of barrel 11 by an annular compression ring 20. Compression ring 20 is held in engagement with the flange 19 of sealing means 18 by a metal cup member 21 whose upper edge is inwardly spun over at 22 to form a permanent assembly. A fur ther washer 23 is disposed within the cup member 21 beneath flaring lip 17 to prevent metal to glass contact between the cup member 21 and the lip 17 which would otherwise tend to cause chipping or breakage of the glass.

At its under side, the resilient sealing means 18 is provided with an annular upwardly extending recess 23a which forms a downwardly depending lip 24 which presses yieldingly against the outside surface of plunger 14 to form a liquid-tight seal, particularly when liquid is being forced outwardly from the barrel 11 by downward pressure on the piston 14. In such cases, the liquid under pressure within the barrel 11 forces the resilient lip 24 of sealing device 13 into firmer engagement with piston 14, thereby increasing the sealing action in response to increased pressure within the barrel 11.

When used for suction, the permissible pressure differential is limited by the stiffness of lip 24 of the sealing means 18 which may allow air to enter before a sufficient suction can be developed for aspiration of the liquid involved.

As may be seen in Figure 2, the piston 14 may be readily entirely removed from the barrel 11 for cleaning or sterilization of the syringe. The piston 14 may be reinserted in the barrel 1'1 whenever desired, passing readily past the lip 24 of sealing means 18.

Figure 3 shows a modified form of the invention in which the cup member 30 is interiorly threaded to receive an annular gland nut 31 which presses on the peripheral flange portion 32 of a resilient sealing member 33. The sealing member 33 is provided with an upwardly extending lip portion 3 and'a downwardly 'extending lip port-ion 35.

Theforrn of inventionshown in Figure 3 is better suited for aspiration'than the form of Figure 1, since atmospheric pressure against the upwardly project-ing lip 34ofresili'ent sealing device33 will increase the pressure of lip 34' against the piston 14.

When used for injection, the pressure within-barrel 11, andbearin-g against the lower lip 35, will augment the sealing action of sealing means 33 as in the case of Figurel.

Figure 4 shows another form of the invention in which the cup member 41 is interiorly threaded to receive a gland nut 42 which bears against the flange portion 45 of a resilient sealing member 44. The cup member 41 and gland nut 42 are provided with outwardly extending ear portions 46 ande, respectively, which facilitate assembly or disassembly of the syringe without the use of tools. The projecting ear portions 46 and d6 of cup member 41 tend to prevent rolling of the syringe when resting on a hat surface.

Asin the embodiment of the invention shown in Figure 3, the resilient sealing member 44 is provided with an upwardly extending lip portion 45 and a downwardly extending lipportion 45 which augment the sealing action during aspiration and injection, respectively. In Figure 4, however, there is an annular internal groove47 formed in sealing member 44 which separates the upper lip portion 45 from the lower lip portion 45'and makes their respective sealing actions more independent of each other.

Figures 6 and 7 illustrate a supplementary member which may be used in connection with the embodiment of Figure 1 or Figure 3 to prevent rolling of the syringe when resting on a flat surface. The suplementary antirolling member, which is shown unfolded in a fiat condition in Figure 6 is shown formed up ready for use in Figure7.

The anti-rolling member is preferably made of springymetal and comprises a flat annular body portion- 7 1 and two upwardly projectingears '72. Body portion 71 is centrally apertured at 73' to receive the barrel 11 of the syringe, the upwardly projecting cars 72 being inwardly turned at their ends to pass over the upper edge of cup member 21 or and thus retain the anti-rolling member positionedupon the syringe.

The resiliency of the upwardly projecting ears 7?. permit them to be sprung apart to place the anti-rolling member upon the syringe, or to remove it therefrom at will.

l-have described What 1 believe to be the best embodiments of my. invention. i do not wish, however, to he confined to the embodiments shown, but what I desire to cover by Letters Patent is set forth in'the appended claims.

Iclaim:

l. A syringe of the class described, comprising: a barrel having-an open end andan outwardly flaring portion at said open end, the end opposite said open end beingadapted for engagement with a hypodermic needle; 2. cup member surrounding said barrel and extending past andsurrounding said flaring portion of said barrel; a loosely fitting piston disposed within said barrel and-slidable therein; resilient sealing means engaging said flaringp'ortion' of said barrel and'said piston resilient washer meansp'os'itioned between said outwardly flaring portion" and said cup member; and annular compression means bearing against said sealing means for retainingthe same in engagement with said flaring portion of said'barrel, said compression means being held in engagement with said sealing means by means carried by said" cup member.

2. A syringe according to claim 1, wherein said resilient sealing means comprises a lip portion extending 1ongitudinally along said plunger.

3. A syringe according to claim 1, wherein said resilient sealing means comprises two lip portions extending in opposite directions alongsaidplunger said two lip portions being separated by an'annular internal groove formed in said sealing means.

4. A syringeaccording to'claim 1', further comprising outwardly extending. ears projectingv from said cup member and fr'om said compression means for facilitating assembly and disassemblyofsaid cup member and said compression means and for preventing rolling of said syringe.

5. A syringe of the class described, comprising a barrel having an open end-and an outward flaring portion at said open end, the end opposite saidopen end being adapted for engagement with a hypodermic needle; a cup member surroundingsaid barrel and extending past and'surrounding said flaring portion of saidbarrel, a loosely fitting piston disposed within saidbarrel and slidable therein, resilient sealing means engaging said flaring portion of saidbarrel and said piston; and annular compression means bearingagainst said sealing means for retaining the same in engagement with said flaringportion of said barrel, said compression means being held in engagement with-said sealing means by means carried by said cup member, saidresilient sealing means comprises two lip portions extending in opposite directions along said plunger.

6'. A syringe'of the class described, comprising a barrel having an open end and an outwardly flaring portion at said open end, aninternally threaded cup member surrounding, said barreland extending past and surrounding saidflaring portion-of said barrel, a loosely fitting piston disposed within said barrel and slidable therein, resilient sealing means engaging said fiaring portion of said barrel and said piston; angular compression means threadably engaging-said cupmember and bearing against said sealing means for retaining the same in engagement with said flaring portion of said'barrel, .said sealing means comprises two lip portions extending in opposite directions along said plunger.

7. A'syringeof the class described, comprising a hollow barrelhaving a cylindrically shapedcavity joined therein, a loosely fittingcylindrical piston freely slidably disposed within said cavity; and a'resilient sealing member fixed to said barrel, said sealingmembercomprising a lip portion surrounding and laterally engaging; said piston for preventing leakage of fiuid'to and fromsaidcavity, said lip portion of saidsealing member extends longitudinally of said piston and is directed both internally and externally with respect to saidcavity.

8. A syringe according to claim 5, further comprising a centrally apertured-anti-rolling member having resilient arms extending. therefrom, said arms being inwardly bent at their ends to grasp saidcup member.

References Cited in the file of thispatent UNITED STATES PATENTS 577,682 Eissner e- Feb. 23, 1897' 786,697 Wackenhuth Apr. 4, 1905 1,592,335 Brody etal July 13, 1926 1,707,880 Sheets Apr. 2, 1929

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