US3506006A - Hypodermic syringe - Google Patents

Description

April 1970 R. LANGE, JR 0 3,506,006

' HYPODERMIC SYRINGE Filed March 21, 1968 l 2 Sheets-Sheet 1 INVENTOR. Richard Lange, Jr. BY

AGENT April 14, 1970 R. LANGE, JR 3,506,006

HYPODERMIC SYRINGE Filed March 21', 1968 2 Sheets-Sheet z Fig. 4

INVENTOR.

Richard Lange, Jr. BY

AGENT United States Patent O 3,506,006 HYPODERMIC SYRINGE Richard Lange, Jr., Harriman, N.Y., assignor to Corning Glass Works, Corning, N.Y., a corporation of New York Filed Mar. 21, 1968, Ser. No. 714,956 Int. Cl. A61m 5/24 US. Cl. 128220 6 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to improvements in hypodermic syringe units and relates particularly to hypodermic syringes that are adapted to be furnished as prefilled sterile units.

Hypodermic syringes require sterilization of the barrel, plunger and needle prior to use since these components, which come in contact with the injectable fluid and patient to be injected, must be free of contamination. By conventional methods there is a need for human handling to load the syringe with the resultant possibility of contamination.

In order to obviate the necessity for sterilizing the components of the syringe and to do away with the necessity of filling the syringe in open air, various prefilled, sealed, sterile hypodermic syringe units have been devised. However, in those devised to date, rubber or plastic closures or pistons are in contact with the fluid from the time that the syringe is manufactured to the time that it is used. This can result in poor shelf life since the fluid may attack the rubber closure causing a flaking of the rubber which contaminates the fluid. The fluid may also have solvent properties which can leach some of the elements from the rubber or plastic pistons and thereby alter the chemical composition of the injectable fluid itself. Further, previous prefilled sterile hypodermic syringe units have required very careful assembly procedures since the filling is done in conjunction with the fabrication of the unit, a very costly and arduous practice.

It is therefore an object of the present invention to provide a sterile, prefilled syringe, in which the fluid does not come in contact with rubber, plastic or metal until the syringe is about to be used.

It is a further object of this invention to provide a sterile prefilled syringe which is simple and economical to fabricate and assemble.

Another object of this invention is the provision of a sterile, prefilled hypodermic syringe in which the hypodermic needle is maintained in a sterilized condition until use.

Another object of this invention is the provision of a sterile prefilled syringe wherein the fluid, until immediately prior to use, is stored in an ampoule.

Another object of this invention is to provide a sterile, prefilled syringe in which a final filtering of the fluid is made just prior to injection.

Other objects of the invention will become apparent from the following description of a preferred embodiment of the invention.

SUMMARY OF THE INVENTION Hypodermic syringe units embodying the present invention provide for the insertion of an ampoule into the upper end of the plunger of the syringe, means for breaking the ampoule upon depression into the plunger, means for forcing the fluid into the barrel of the syringe, means for filtering the fluid as it is forced from the plunger into the barrel of the syringe and means for preventing the flow of the fluid from the barrel back into the plunger once the desired amount of fluid has been transferred.

BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is a sectional view of a preferred embodiment of the present invention before use.

FIGURE 2 is a sectional view of the preferred embodiment of the invention after depression of the ampoule into the plunger.

FIGURE 3 is a sectional view of the preferred embodiment of the invention after depression of the plunger into the barrel of the syringe.

FIGURE 4 is a sectional view of the preferred embodiment of the invention after partial Withdrawal of the plunger from the barrel.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGURE 1, the preferred embodiment comprises a syringe 10, having a barrel 11, a needle 12 and a plunger 13. Barrel 11 is a generally cylindrical tubular length of glass or plastic or any of the conventional materials of which syringe barrels are formed. The upper end 14 of barrel 11 is open and has a flange 15. The other end 16 of barrel 11 is closed except for hole 17 in which needle 12 is anchored in the conventional manner. The outside of end 16 of barrel 1]. has threads 18 upon which is threaded, in an airtight fashion, needle protector 19. Needle protector 19 is a generally cylindrical body being closed at its lower end and threaded internally at its upper end, and, as is shown in the drawings, acts as a cover for needle 12. The connection between needle protector 19 and barrel 11 by means of threads 18 is airtight not only to avoid contamination of the needle before use of the syringe but also to enable filling of the syringe as hereinafter described.

Plunger 13 is a generally cylindrical glass body, one end being shaped in the form of a flange 20. Aroundthe other end is attached a rubber or plastic piston 21 in the form of a cylindrical sleeve extending around the bottom and sides of projection 22. The connection between piston 21 and plunger 13 is made by means of a cylindrical projection 22 having an annular depression 23. Annular internal ridge 25 on piston 21 interlocks with depression 23.

In assembly, piston 21 is forced into plunger 13 so that ridge 25 fits into depression 23 holding them together. The fit of piston 21 on plunger 13 is purposely made loose so that the frictional torque between projection 22 and the inner surface of the piston is less than the frictional torque between piston 21 and the interior wall of barrel 11. This is important for the operation of the syringe as will be more fully explained later. Piston 21 is positioned inside barrel 11 in the usual manner so as to allow the piston to be pushed down or up barrel 11 in an airtight fashion. Hole 26 in piston 21 is located off center of the centerline of piston 21, insuring that the centerline of piston 21 is never encompassed by hole 26.

Inside projection 22, in cooperative relationship with hole 26, is hole 27. As assembled, holes 26 and 27 are in line with each other. The other end of plunger 13 has a cylindrical cavity 28 having a truncating projection 29 at the end near projection 22. Between cavity 28 and hole 27 is located a filter 30. In cavity 28 is positioned, globe first, an ampoule 31 prefilled in the usual fashion with the liquid to be injected, Globe 34 of ampoule 31 has a circumferential score line 36 located between tip 35 and the bulb of globe 34. Sealing ring 32 holds ampoule 31 in place and provides an airtight fit of ampoule 31 in plunger 13. A rubber or plastic cover 33 covers the exposed end of the ampoule to insure protection against contamination before use.

In operation, the syringe is first heid in a vertical position, plunger end up and needle end down. In this position, the syringe is as shown in FIGURE 1. Plunger 13 is then held firmly from the outside and ampoule 31 is driven into the lunger by pressing on cover 33 untii frangible tip 35 of ampoule 31 is driven against truncating projection 29, snapping it at score line 36. The syringe is then as is shown in FIGURE 2.

Next, plunger 13 is driven all the way into barrel 11, as shown in FIGURE 3. Since no air or gas can escape out through needle protector 19 because of its airtight connection with threads 18 of barrel 11 between the walls of plunger 13 and barrel 11, the air or gas previously filling the cavity in barrel 11 and needle protector 19 is compressed forcing it to pass through hole 26, hole 27, filter 30 and into ampoule 31. At this time, the pressure in both barrel 11 and plunger 13 has been increased beyond the pressure present therein prior to use. Next, plunger 13 is slowly pulled up barrel 11 away from hole 17. In so doing, the vacuum created in barrel 11 and the additional pressure in plunger 13 causes a pressure differential to exist across filter 30, forcing the fluid to be driven through filter 30 into the growing cavity in barrel 11. This is continued until more than the required dosage of the fluid has accumulated in barrel 11.

At this point, plunger 13 is rotated 180 with respect to barrel 11. Since the frictional torque between projection 22 and piston 21 is less than the frictional torque between piston 21 and barrel 11, plunger projection 22 will rotate inside piston 21 without any rotation of piston 21. After this is accomplished, holes 26 and 27 are no longer aligned and there is no communication between them. The upper end of hole 26 now abuts the solid end of projection 22 and the lower end of hole 27 now abuts the solid wall of piston 21. The condition of the syringe is now as is shown in FIGURE 4. At this point, the syringe is not uniike any conventional syringe. After needle protector 19 has been removed, the syringe is then expirated until all the air or gas is driven from that portion of barrel 11 between piston 21 and needle 12 and from the needle, until the exact dosage remains. It is then ready for use and is thereafter used as is any ordinary syringe.

It should be noted that the provision of filter 30 provides for a final filtering of the fluid just prior to injection. Along with any glass particles resulting from breaking of ampoule 31, any solids which may have been included in the fluid in assembly of the ampoule are filtered out.

Ampoule 31 may initially be sealed with a positive internal pressure greater than that of the syringe interior, thereby facilitating the flow of liquid from the ampoule to the syringe when the ampoule tip is broken. Similarly, the interiors of the plunger and barrel may be maintained at a negative pressure to facilitate flow from the ampoule.

Further, the invention provides for the use of an ampoule and eliminates the need for costly assembly to insure uncontaminated filling of syringes as in present prefilled syringes. Also, while the syringe is in storage prior to use, there is no contact between the liquid and any rubber or plastic pistons or sealing rings. The liquid during this period of time is in contact only with the glass of ampoule 31. Consequently, the possibility of contamination of the fluid by reaction with the rubber or plastic or by flaking of the rubber or plastic is eliminated. Contact between the fluid and the rubber or plastic is of very short duration regardless of shelf life and so the shelf life of a syringe embodying the invention is limited only by the shelf life of the ampoule.

Inasmuch as the foregoing description has been provided solely as that of the preferred embodiment of the invention, the scope of the present invention is to be limited only by the scope of the appended claims.

What is claimed is:

1. A hypodermic syringe comprising a hollow barrel,

a hypodermic needle communicating with the interior of said barrel at a first end thereof,

a hollow plunger reciprocable within said barrel through a second end thereof,

a fluid container within said plunger,

means for opening said fluid container to permit flow of fluid from said container to said plunger,

means for reciprocating said plunger in said barrel,

means forming a channel between said plunger and said barrel for the flow of fluid therebetween,

means for opening and closing said channel, and

removable closing means for closing said needle to prevent fluid flow therethrough,

whereby fluid is able to pass between said plunger and said barrel when said channel is open and said plunger is operable to expel fluid through said needle when said channel is closed and said closing means is removed from said needle.

2. A hypodermic syringe according to claim 1 in which said fluid container is an ampoule reciprocable within said plunger and having a frangible tip extending generally in the direction of said needle, and

said means for removing said frangible portion is a projection on the inner wall of said plunger in the vicinity of said frangible tip and at a location to exert pressure on said frangible tip as said ampoule is moved in the direction of the end of said plunger within said barrel, and

which includes means for moving said ampoule in the direction of the end of said plunger within said barrel.

3. A hypodermic syringe according to claim 1 which includes filter means between said fluid container and said barrel in a position to filter fluid passing therebetween.

4. A hypodermic syringe according to claim 1 in which said means for opening and closing a channel between said plunger and said barrel comprises a piston at the end of said plunger within said barrel and rotatable with respect to said plunger,

a first fluid channel passing through said plunger at its end within said barrel, said fluid channel being olfset from the centerline of said piston,

a second fluid channel passing through said piston, said second fluid channel being offset from the centerline of said piston by substantially the same distance as that by which said first channel is offset, and

means for elfecting relative rotation between said piston and said plunger,

5. A hypodermic syringe according to claim 4 in which said piston is in the form of a sleeve having cylindrical inner and outer surfaces and extending around the side and end of a cylindrical projection extending from the end of said plunger, and

said sleeve is in engagement with the inner surface of said barrel, such that relative rotation between said plunger and said sleeve can be elfected by rotation of said plunger to effect or interrupt communication through said channels between the interiors of said barrel and the interior of the plunger.

6. A hypodermic syringe comprising a hoilow barrel having a cylindrical inner surface,

a hypodermic needle communicating with the interior of said barrel at a first end thereof,

a hollow plunger having a cylindrical outer surface and being reciprocable within said barrel through a second end of said barrel,

at least a portion of said inner surface of said plunger being cylindrical,

an ampoule within said plunger having at least a portion of its outer surface in the form of a cylinder complementary to the cylindrical inner surface of said plunger and having a frangible tip extending toward the end of said plunger nearer said needle,

an inwardly projecting portion on the inner surface of said plunger adapted to break off said frangible tip on said ampoule when said ampoule is moved in the direction of said needle,

a cylindrical projection on said plunger concentric with the cylindrical surfaces of said plunger and extending in the direction of said first end of said barrel,

a sleeve extending around the side and end of said projection on said plunger, said sleeve having a cylindrical inner surface complementary to the outer surface of said projection and a cylindrical outer surface complementary to the cylindrical inner surface of said barrel,

said sleeve being in frictional engagement with said projection and said barrel, the frictional force between said sleeve and said barrel being greater than 2 the frictional force between said sleeve and said projection, whereby rotation of said plunger effects relative rotation between said plunger and said sleeve,

said plunger having a fluid-flow channel extending through said projection and communicating with the interior of said plunger,

said sleeve having a fluid-flow channel extending therethrough,

said fluid-flow channels being offset from the centerline of said cylindrical surface of said projection by equal amounts such that relative rotation between said plunger and said sleeve can bring said channels into and out of communication with one another, and

filter means located between said frangible tip of said ampoule and said hypodermic needle for filtering fluid passing therebetween.

References Cited UNITED STATES PATENTS 2,841,145 7/1958 Epps 128--218 3,076,456 2/1963 Hunt 128--218 3,348,546 10/1967 Roberts et al. 128218 RICHARD A. GAUDET, Primary Examiner G. F. DUNNE, Assistant Examiner US. Cl. X.R.

Images