US1641976A - Hypodermic syringe - Google Patents

Description

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P 7 A. A. LAURENT HYPODERMIC SYRINGE Filed Aug. 21, 1926 Inventor.- f K Laurent.

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Patented Sept. 13, 1927.

ANTOINE A. LAURENE OF MINNEAPOLIS, MINNESOTA.

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Application filed August 21, 1926. Serial No. 130,761.

My invention relates to hypodermic syringes, and has for an object to prov de a syringe which can be held and operated with' great convenience and which can be 5 maintained filled with a supply of liquid to be injected hypodermically into the human body. This syringe is employed to in ect liquid into the human body for the production of what is known aslocal anaesthesia, and may also be used for injecting serums and vaccines. It is essential for producing local anaesthesia to introduce relatively large quantities of the liquid into the area to be anaesthetized and it is therefore desirable that a syringe be provided which can be refilled or .kept 'in filled condition without havin to remove the hypodermic needle after has been inserted. This invention is in the nature of an improvement on Patent No. 1,367,008grantedFeb. l, 1921, to A. N. Bessessen, and involves an improvement on the valvec'onstruction'and arrangement disclosed in said patent. The full objects and advantages of my 1nvention will appear in connection-with the detailed description thereof, and the "novel features of my inventive idea will beparticularly pointed out in the claims. In the accompanying drawings which lllustrate a practical embodiment ofmy invention,- I Y Fig. 1 is a view of the device partly in elevation and partly in central-vertical section and showing the plun er moved in- 2 is a view 0 the device-in central vertical section showing the plunger moved outwardly. Fig. 3 is a view in cross section on the line 3-3 of Fig. 2.

Referring to the drawings for thepurpose 3 of describing the invention in detail, the syringe comprises acylindrical barrel 10 which at its forward end is threaded toreceive aperforated cap 12. This cap is in turn threaded at its forward end to receive ahypodermic needle 14. The interior of the forward end of thebarrel 10 is provided with avalve seat 16 with which a forwardly openingcheck valve 18 is adapted to cooperate, being normallyheld upon the valve seat by aspring 20. Thevalve 18 is in the form of a ball to which is secured astem 22 extending out through the passage in thecap 12 but smaller than this passage so as not to prevent the flow of liquid therethrough. The rear end'of the barrel. 1() is'provided with ascrew cap 24 havingtwo lateral diametrically opposed curved finger grips Slidable' inthebarrel 10 is ahollow plunger 28 having ahead 30 at the lower end thereof, and atransverse partition 32 intermediate the upper and lower ends. The upper surface of the head SO'is provided centrally with arounded recess 34 from whichperforations 36 extend to the lower surface of the head. These perforationsare located outside of the axialline of the plunger. The lower sideof thepartition 32 is provided centrally with arounded recess 38. Therecesses 84 and 38 constitute seats for aball valve 40 having a limited movement between the two seats. Arod 42 extends upwardly from theball 40, this rod being hollow to provide apassage 44 which is extended cen-' trally through the ball. Therod 42 in effect constitutes a plunger rod. Tightly secured upon the rod42 is asleeve 46 which except for convenience in manufacture might be made integralwith the rod. Thesleeve 46 passes snugly through a central opening in thecap 24 and at its upper end is threaded to receive an internally threadedboss 48 formed on a-handpiece 5O shaped to receive the palm ofthe hand. Thehand piece 50 contains apassage 52 which communicates withthepassage 44 and extends through anipple 54 to which is attached apiece ofrubber tubing 56, adapted to be connected with the source of supply of liquid. The lower end of thesleeve 46 has aflange 58 to which is anchored a coiled spring 60 whose upper end is anchored to aring 62 held between thecap 24 and the upper end of thebarrel 10. I

In use, the hypodermic needle may be readily inserted where desired in the human body and with the fingers around the finger 9grips 26 and the palm of the hand upon thehand piece 50, pressure is exerted upon the plunger to cause the liquid below the latter to be forced through the needle into the part to'be anaesthetized or into whichrserum or vaccine is to be injected. At the same time, the spring 60 is stretched and the ball valve moves fromtheupper seat 38 into engagement with thelower seat 34; Upon releasing the pressure of the hand, the spring retracts the plunger thereby producing a vacuum in vthe barrel below the plunger and causing liquid to flow from the source of supply into the vacuum chamber, theball 40 then being in the position shown in Fig. 2 so that there is a free passage through theball 40 and theperforations 36. Upon starting to depress the plunger. thehall 40 first moves into position upon theseat 34 as shown that back-How of the liquid is prevented. lVhile the ball has a limited amount of movement between the two seats, the construction in effect constitutes a ball and socket connection between the plunger and its rod so that there is no liability of the plunger being subjected to side thrust which might cause it to bind. The ball. therefore, has a three-fold function since it acts as a check valve when in the position shown in Fig. l and allows the liquid to pass directly therethrough when in the position shown in Fig. There is a special utility for thestem 22 attached to thecheck valve 18 due to the fact that there is liability of this valve becoming stuck to its seat after the device has been used. hen such sticking occurs, the valve is readily released by pushing sidewise on the projecting end of the stern when the needle is detached.

I claim:

1. In a hypodermic syringe having a barrel provided with an outlet opening containing an outwardly opening check valve, the combination of a plunger working in said barrel, a plunger rod, a ball on the inner end of said rod for connecting the latter with said plunger and having a limited movement with relation thereto, said rod and ball together having a passage for liquid, a perforated head for said plunger with which said ball engages when in forward position for preventing backward How of liquid through said passage, and means for conin Fig. 1 so necting the outer end of said rod with a source of lhpiid supply.

2. In a iypodermic syringe having a barrel provided with an outlet opening con taining an outwardly opening check valve, the combination of a plunger working in said barrel, a plunger rod, a perforated head and a transverse partition for said plunger, said head and partition having rounded recesses facing each other, a ball on the inner end of said plunger rod having a limited movement between said recesses, said ball and rod together having a passage for liquid, said hall when in forward position engaging the recess in said head for preventing backward flow of liquid through said passage, and means for connecting the outer end of said rod with a ply.

3. In a hypodermic syringe having a barrel provided with an outlet opening containing an outwardly opening check valve. the combination of a plunger working in said barrel, a spring for normally holding said plunger in retracted position, a plunger rod, a ball on the inner endoi' said rod for connecting the latter with said plunger and having a limited movement with relation thereto, said ball and rod together having a passage for liquid, means for preventing backward flow of liquid through said passage, and means for connecting the outer end of said rod with a source of liquid supply.

In testimony whereof I hereunto aflix my signature.

ANTOINE A. LAURENT.

source of liquid sup-

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