US 3685514 A
A disposable, two compartment syringe assembly which is separated into a first compartment formed by an outer barrel and a second compartment formed by an inner barrel; the inner barrel being partially inserted into the outer barrel. A tight fitting, but slidable plunger is provided in the inner barrel. Two materials which are desired to be mixed shortly before ejection from the syringe are stored separately in the first and second compartment formed by the inner and outer barrels. An opening at the bottom of the inner barrel is sealed off from the compartment in the outer barrel by means of a cap of extendable and resilient material which has a protrusion fitted in sealing contact with the opening in the inner barrel. At least one opening is provided in the cap and adjacent to the protrusion so that when the plunger is forced downwardly within the inner barrel, the material stored there exerts a pressure against the protrusion and a path is formed from the inner barrel through the opening in the cap thus permitting the material to be forced into the compartment formed by the outer barrel. There it is mixed with the material in the outer barrel and by pushing the inner barrel into the outer barrel, the inner one acts as a plunger and the mixed material may be forced through a needle attached to the bottom of the outer barrel.
Description (OCR text may contain errors)
United States Patent Cheney [151 3,685,514 1 Aug. 22, 1972 I541 TWO COMPARTMENT SYRINGE  Inventor: Paul E. Cheney, 76 Summer Road,
Fitchburg, Mass. 01420  Filed: Sept. 23, 1969  Appl. No.: 860,270
 US. Cl. ..128/218 M, 128/220  Int. Cl. ..A6lm 05/00  Field of Search....l28/2l8 R, 218 M, 218 P, 218 PA, 128/220  References Cited I UNITED STATES PATENTS 1,799,463 4/1931- Hein ..128/220 2,666,434 l/l954 Ogle ..128/218 P 2,869,543 l/l959 Ratcliff et al ..128/218 M 2,869,544 l/1959 Ratcliff et al ..128/220 3,050,059 8/1962 Wall et al. ..128/218 P 3,135,260 6/1964 Hamilton ..128/218 R 3,303,846 2/1967 Ogle ..128/218 M FOREIGN PATENTS OR APPLICATIONS 751,203 6/1956 Great Britain ..128/220 Primary Examiner.loseph S. Reich Att0rney-Curtis, Morris & Safford  ABSTRACT A disposable, two compartment syringe assembly which is separated into a first compartment formed by an outer barrel and a second compartment formed by an inner barrel; the inner barrel being partially inserted into the outer barrel. A tight fitting, but slidable plunger is provided in the inner barrel. Two materials which are desired to be mixed shortly before ejection from the syringe are stored separately in the first and second compartment formed by the inner and outer barrels. An opening at the bottom of the inner barrel is sealed ofi from the compartment in the outer barrel by means of a cap of extendable and resilient material which has a protrusion fitted in sealing contact with the opening in the inner barrel. At least one opening is provided in the cap and adjacent to the protrusion so that when the plunger is forced downwardly within the inner barrel, the material stored there exerts a pressure against the protrusion and a path is formed from the inner barrel through the opening in the cap thus permitting the material to be forced into the compartment formed by the outer barrel. There it is mixed with the material in the outer barrel and by pushing the inner barrel into the outer barrel, the inner one acts as a plunger and the mixed material maybe forced through a needle attached to the bottom of the outer barrel.
2 Claims, 5 Drawing Figures 2 SheetS -Sheet 1 INVENTOR ATTOR TWO COMPARTMENT SYRINGE DISCLOSURE OF THE INVENTION The present invention relates to improved and disposable syringes of the type having two compartments. More particularly, the invention relates to hypodermic syringes where two materials are stored in separate compartments until shortly before they are gesiired to be used as a mixture and injected into a The use of two compartment disposable hypodermic syringes is well established. In many cases it is desired to keep a powdered pharmaceutical or medicament in one compartment of the syringe sealed 03 from a diluent or solvent stored in another compartment. Just prior to use, the diluent or solvent is forced through some sealing means into the'compartment containing the pharmaceutical or medicament. There they are mixed together and then the inner barrel of the two barrel unit is used as a plunger to force the mixture out through a hypodermic needle.
Typical two compartment syringes are shown in prior art patents such as U.S. Pat. No. 3,052,239, issued Sept. 4, 1962 to Jules Silver et al. and U.S. Pat. No. 3,380,451, issued Apr. 30, 1968 to Robert E. Porter et al.
Heretofore, two compartment syringes have generally required special valves and seals to keep the two materials separated. As far as it is known, none have been completely satisfactory from the view point of economy, ease of production and safety.
Accordingly, it is an object of the present invention to provide an improved disposable syringe which is economical to manufacture, has a minimum number of parts to assemble, is easy to use, and may be discarded after use.
These and other objects and advantages of the present invention will be obvious from a description of the illustrated embodiment as shown in the drawings. While the drawings and the illustrated embodiment are for the purpose of enlightening those skilled in the art, the single embodiment is not to be considered as limiting the invention.
IN THE DRAWINGS Drawings FIG. 1 is an exploded side view showing the various components of the present invention;
FIG. 2 is a sectional view of the two compartment syringe of the present invention;
FIG. 3 is a top view of the cap seal for the inner barrel of the present invention;
FIG. 4 is a partially fragmentary side view of the hypodermic syringe of the present invention showing the action of the plunger when forced downwardly within the inner barrel; and
FIG. 5 is a partially fragmentary sectional side view of the syringe showing the action when the inner barrel is slid as a piston within the outer barrel.
Referring to the drawings and to FIG. 1 in particular, a syringe 10 in accordance with the present invention is shown as an exploded assembly of five components. The syringe is comprised of: an outer barrel 12, an inner barrel 14, a plunger 16 which is inserted into the inner barrel, a cap 18 which acts as a seal and is fitted over the end of the inner barrel, a needle 20 which may be integrally connected to the outer barrel or may be attached thereto and a cover 22 for the needle 20. If the needle 20 is to be made integral with the barrel 12, it will usually be of the same material as the barrel, such as polyethylene.
In such cases with a plastic needle 20, it is obvious that it would not be usable for piercing the skin. Such needles are usually used for insertion into an opening, for example in vetenarian use into the teat of a cow.
As shown in FIGS. 1, 2, and 3, in particular, the outer barrel 12 is comprised of a side wall 24, a bottom wall 26, and an opening 27 in the bottom wall. The opening 27 communicates with the needle 20 and serves as a passage for any materials to be ejected from the syringe through the needle. The interior of the outer barrel 12 serves as a first compartment 28 for storing a material 30 which will be one of the components of the mixture ejected through the needle 20.
The inner barrel 14 is tightly but slidably fitted within the side wall 24 of the outer barrel 12, so that when the inner barrel 14 is depressed, it serves as a piston in relation to the outer barrel 12.
The inner barrel 14 includes a side wall 32 and a bottom wall 34. The bottom wall 34 has a sloped or tapered portion 36 which converges in a central opening 38. In order to seal off the opening 38 from the lower compartment 28 in the outer barrel 12, the cap 18 is fitted over the lower end of the barrel 14. The cap 18 is advantageously made of flexible and resilient material such as any of the well-known rubbers or plastics, and includes a side wall 40 and a bottom wall 42. On the bottom wall 42, a protrusion 44 is provided and the protrusion fits in sealing contact with the opening 38. Also provided in the bottom wall 32 is a pair of openings 46. When the protrusion 44 is in place, as shown in FIG. 2, in particular, the openings 46 are closed off from the opening 38 in the bottom wall of the inner barrel. In order to maintain the cap 18 in place, a bead 48 is provided on the side wall 40 and this bead fits into a groove 52 in the inner barrel 14.
Since the'cap l8 and particularly the protrusion 44 seals off the inner barrel from the lower compartment 28, a second material 54 may be stored in the upper compartment 55 formed within the inner barrel.
The plunger 16 is inserted into the inner barrel 14. The plunger consists of a seal piece 56 which tightly fits within the side wall 32 and has attached to it a stem portion 58. A pressure plate 60 is attached to the end of the stem.
In order to permit a user to force the plunger 16 into the inner barrel 14, a flange 62 is provided on the inner barrel. The flange 62 serves as a finger support when the thumb of the user is placed against the piece 60. After the plunger 16 has been inserted into the inner barrel 14, the inner barrel may be used as a piston within the outer barrel 12. To assist the user another flange 64 is provided on the outer barrel as a finger support.
As shown in FIG. 4, when the plunger 16 is depressed into the upper compartment 55, the material 54 (which in many cases will be a' dilutent or solvent for the material 30 in the lower compartment 28) will be forced into the opening 38. From there the material 54 is forced against the cap 18 which because of its flexible and extensible nature gives way under the pressure permitting the protrusion 44 to move out of contact with the opening 38. This provides an open channel from the .upper compartment 55 through the opening 38 and then finally to the openings 46. Because the material 54 is being forced under pressure by the action of the plunger 16 and due to the narrowness of each of the openings 46, the material 54 passes into the lower compartment in a jet-like action and mixes rapidly with the material 30.
When the material 54 has passed through the opening 38 and the plunger 16 has made its full travel through the inner barrel, theinner barrel 14 is then ready to be used as a plunger. When depressed the bar rel l4 forces the mixture of materials 30 and 54 out through the opening 27 into the needle 20, as shown in low-cost plastic material, such as polyethylene. The cap I 18 may be made of a suitable flexible and extensible material such as a synthetic rubber or a plastic. The plunger 16 may be made of a material such as polyethylene or polypropylene. The only requirement is that thematerial be preferably and advantageously self-lubricating to permit it to move slidably through the inner barrel 14 without the need of additional lubrication.
The needle 20 if it is to be used to make an injection through the skin of a body of a human or an animal of course must be of a metallic nature such as a hollow steel needle. 0n the other hand though, if it is to be inserted into an opening such as the canal in the teat of a cow, it can be of a plastic material and molded integrally with the lower barrel 12.
From the foregoing it is obvious that the present invention meets the objects and requirements as set forth hereinbefore.
What Is Claimed:
1. A two compartment syringe of the type adapted to be used with a hollow needle, comprising:
an outer barrel having side and bottom walls forming a first compartment and an opening in the bottom wall adapted to be connected to the needle,
an inner barrel in slidable but liquid-tight relation within the side wall of the outer barrel, said inner barrel having side and bottom walls forming a second compartment and an opening in the bottom wall connecting the first and second compartments,
a cap of resilient and flexible material fitting over the end of the inner barrel, said cap having side and bottom walls, said bottom wall having a protrusion thereon adjacent to the opening in the bottomwall of the inner barrel in normal sealing relation therewith, and atleast one opening in the bottom cap wall, and a plunger positioned within the side wall of the inner barrel in slidable but liquid-tight relationship whereby said plunger may be depressed towards the cap so that any material in the second compartment will pass through the inner barrel opening against the cap protrusion causi the, rotrusi n to cear, 'd o there g fOl'lIllRg a pa through said ap 0 nm to permit said material to mix with any other material in the first compartment; a groove at the lower end of the inner barrel and a bead on the cap, said bead fitting into the groove whereby the cap is held in place against the pressure developed by a stroke of the plunger while permitting the protrusion to be moved-from sealing contact with the inner barrel opening; the inner barrel being nin