US 1705525 A
Description (OCR text may contain errors)
March 19, 1929. A
F. J. HOFSCHNEIDER HYPODERMIC SYRINGE Filed Nov. 5, 1925 IIHII IIIIIHI IIHIIIIII f .about the stated results with a simple con- Patented Mar.Y 19, 1929.
FREDERIC J. Henson-Namen, or ROCHESTERy NEWYOBK.
HYPODERMIC svn-men Application led November My invention relates to a hypodermic syringe, and has for its principal object to aord a durable, efficient, and economical all metal construction, such that it can be thor,- oughly sterilized, and is adapted for dentists use.
A more particular purpose of the improvement is to afford an arrangement that permits a needle carrier to be held in operative relationship to the barrel of a syringe solely by. frictional engagement, thus eliminating the necessity of attaching means for the needle carrier.
An additional object of the invention is to construct and hold the needle carrier in such manner as to afford a thoroughly water-tight connection while making it possible to position or remove the needle carrier instantly and without difiiculty. v
Still another purpose of the improvement is to attach a needle within a needle carrier in such mannerv as to permit sufficient flexibility of the needle to prevent ready breakage, thus increasing the life of the needle by causing it to withstand any ordinary stra-ins to which it may be subjected.
A further object of the invention is to af-` ford a watertight connection between thek piston and barrel of a syringe without employment of washers of leather, soft metal, or the like, and to accomplish this result with a part or partsV formed Vof hard metal and `constructed so as to be elastic. s l
An additional purpose of the invention is to afford an arrangement that permits 'of quickly and. effectively gripping thevpiston, to produce a water-tight connection between it and the barrel of the syringe, by means of an elastic, hardfmetal unit.
A Jfurther object of the invention is tobring struction and arrangement of parts that can be manufactured at a low cost, giving to the user a structure that will stand up successfully under hard, long` usage and which can be thoroughly sterilized Without taking apart. K
Vith these and other ends in view, the invention includes the form and arrangement of parts that will appear clearlyfrom the following description when'read in conjunc` .tion withrthe accompanying drawings, the novel features being pointed out in the claims following the description.
In the drawings:
Figure l is a side elevation of a hypodermic 5, 1925. vserial No.` 67,144.
syringe made in accordance .with one embodiy Figure l is a similar View showing a slightly modified form of needle carrier ;l
Figure 5 1s an elevation of the lnner end of the needle carrier 5' Figure 6 is a detail sectional view of the sleeve used to tighten the gripping vmember about the piston, and
Figure 7 is a detail side elevation of the needle carrier, showing a portion of the syringe barrel in sectionand illustrating the piston handle in position when used to remove the needle carrier from the barrel. l
The various features ofrmy invention may be carried out in many differentways, and the several arrangements herein shown are intended merely as exemplary of' various possible practical embodiments.
In vthe arrangement shown, l designates the barrelof a syringe,- 2 is the piston, and 3 is the piston handle, which will be referredto The barrel l isy providedlwith a tapered openingfat its outer end to receive Va needle more fully hereinafter.
carrier 4 whichhas an exterior surface tapered correspondingly with the opening in the barrel, and adapted to be held in the bar- ,rcl solely by frictional engagement. The in- `ner end of the needle carrierihas a reversely tapered portion 5 providedwith sediment K deflecting means, preferably in the form of a spiral groove which acts, as the piston is forcedinwardly, to cause any heavy particles in the fluid to be swirled to the side wall of the barrelv and retained in the pocket 7.
8 designatesv a needle, rigidly secured to the carrier at the rear end ofthe latter, as designated at 9, either by soldering, compression of the carrier, or in any other suitable manner. Exceptrwhere the needle is attached at the rear end of the carrier, it is free from the adjacent walls ofthe carrier. The latter is preferably provided with an enlarged opening at its centralportion having concave walls 10, and a reduced portion formed.
. end of the opening being flared as at 12.
This arrangement permits the needle to be flexed throughout its length as it'meets with,v
resistance and prevents it from breaking as v a fine gauge needle is used, the arrangement of Figure 4 is preferable. In this arrangement, the inwardly projecting portions 13 of the carrier are in contact with the needle, although not connected thereto, and serve to brace the needle at this point,while at the same time permitting endwise movement and flexing of the needle. The needle carrier may be provided with a series of annular grooves 14 in its tap-ered surface which act to create a tighter and more perfect union with the surrounding tapered surface of the barrel, since the sharp edges afforded by the grooves have a tendency to finish the surface of the barrel or remove any slight irregularities each time the needle carrier is forced into position. j
To assemble the needle carrier in the barrel, the piston 2 must first be removed. The needle carrier is then dropped in the upper end of the barrel and permitted to fall into the lower end. Then by inserting the piston and slightly tapping the inner end of the needle carrier, the latterV is properly positioned and is held frictionally until removed by a blow or suflicient pressure upon the outer end of the needle carrier. When desired to remove the needle carrier for steriliz'ing the parts, ifthe needle is worn out or broken, a blow upon the outer end of the needle carrier will loosen 'and permit it to drop out of thebarrel, after the piston has been first removed. If it is desired to'preserve the needle and remove the needle and carrier from lthe barrel, the portion 15 of the handle 3 is employed. The piston being removed from the barrel, the opening 16 of portion 15 is positioned over the needle and against the outer end of the carrier as shown in Figure 7, and a sufficient pressure on the needle carrier can vbe then exerted to loosen it from the barrel,
withoutr damaging the needle. I will now describe the parts which serve to form a water-tight connection between the piston and barrel. *j
The practice heretofore has been to employ Washersof soft metal, leather, asbestos,
or other compressible material to effect a. liquid-tight joint between the barrel and piston. This has the disadvantages that'with leather or asbestos, sterilization is not practically feasible, and where soft metal is employed, it is quickly rendered useless by distortion, and frequent movement of the piston causes particles of the metal to chip off and get into the hypodermic solution. To overcome. these objections, I have devised a joint that utilizes only hard metal, which is elastic but not of the needle carrier.
normal position and release the piston when pressure is removed. The outer surface of the piston-gripping cylinder is tapered as shownl and provided with a series of parallel annular grooves 22 aiiording intermediate rings 23, and permitting sufficient elasticity in the cylindrical portion 21 so that it may be compressed about the piston 2 without being permanently distorted. This action of the piston-gripping cylinder' may be brought about by a sleeve 24 having an inner tapered surface 25 that engages ythe correspondingly tapered surface of the piston-gripping. cylinder portion. The sleeve 24 is threaded interiorly at its lower end to engage a threaded portion 26 on the barrel and by turning the sleeve 24 so as to thread it on the barrel, its tapered surface forcing against the tapered surface on the piston gripping cylinder. coinpresses the latter around the piston 2. lVith very little effort, a sufficiently tight engagementbetween these parts can be obtained to prevent any loss of liquid between the piston and barrel. j
In order to turn the sleeve 24, it is provided with a keyway 2T that is engaged by a corresponding key 28 on the handle portion 3 of the piston, see Figure2. In this way, the sleeve 24 is tightened by a slight turning movement of the handle 3 and piston with the latter in position in the barrel, and may be loosened in the same manner.v 29 is a hammer portion on the handle that is used to knock the needle carrier from the barrel when the needle is broken or Worn out. Under these conditions, thek needle carrier is removed by tapping its outer end" with the hammer portion 29.
In using the syringe, assuming it to be disassembled, a needle carrier is dropped into the upper end of the barrel 1 with the needle 8 pointing downwardly, so that when it falls to the lower end of the barrel it assumes the position shown in Figure 2. The piston 2 is then inserted and pushed downwardly into the barrel to impose pressure on the inner end This forces the needle carrier into suiiiciently tight frictional engagement with the barrel to retain it in place. The piston being in position, the keyl 28 is then brougl'it into engagement with the keyway 27 and piston handle 3 turned until sufficiently tight engagement is had between the piston and piston-gripping cylinder to permit free movement of the piston and yet preprevent loss of liquid. The parts are then ready for operation and the piston may be removed to permit filling the barrel with the necessary liquid. Thereupon the piston is 'again inserted and the device is ready for use upon a patient.
IVhile I have described the various features of my invention with reference to certain more or less particular embodiments, it is not restricted inV its application to the details set forth, but may be used in variousl Ways Without departing-from thev underlying features of the invention or the scope of the following claims.
I claim: i
l. In a hypodreinic syringe, the combination With a bari'el having an opening which tapers toward its outer end, ot' a correspondingly tapered quickly removable needle carlriei` coperating With said tapered opening in the barrel and held therein solely by frictional engagement, the taper of the barrel and carrier beingsuch that the liquid pressure Within the syringe tends to tighten the carrier in the barrel.
2. In a hypodermic syringe, the lcombination with a barrel having a tapered opening, Y of a needle carrier having a correspondingly tapered portion adapted toit in said opening and held there solely by rictional engagement, said tapered portion of the needle carrier being provided With a series'of'concenti-ic grooves.
3. In a hypoderinic syringe, the combina-k tionvvith a barrel having a tapered opening, ot a needle carrier having a correspondingly tapered portion adapted to fit in said opening and held in the barrel solely by rictional engagement, the needle carrier having a reversely tapered portion at its inner end pro- 4vided With sediment detlectiiig means.
4. In a hypodermic syringe, the combinationWith a barrel having an opening'which tapers toward its outer end, of a correspondingly tapered, quickly removableneedle carV rier cooperating With said tapered opening in the barrel and held therein solely byfrictional engagement, the needle carrier having an opening extending centrally, a needle arranged in said opening'with its inner end FREDERIC J. HOFSCHNEIDER.