Injector

1. Field of the Invention

An instant injector may be, after use, thrown away or re-used, and even at emergency it may be rapidly charged with a liquid medicine containing cartridge.

2. Description of the Prior Art

There have already been proposed such urgent case's injectors that an injector body as a tube has been in advance filled with injecting liquid, and a mouth is tight-sealed with a temporary cover pierced with a needle. Such an injector is also known that an injector tube is integrally composed with an injecting needle and is prior filled with the medicine liquid and the needle is sealed on its end point. Since a squeezing tube is pressed by the operator with his fingers, it would be deformed and could not always inject a determined amount of the liquid, and it would take a fairly long time. For the medicine liquid contained in the injector, precision is required to sliding between a cylinder and a piston, otherwise the liquid will leak and a piston stopper should be provided.

An object of the invention is to provide a cartridge type injector which could be operated rapidly and exactly even at the urgent occasions.

Another object of the invention is to provide a cartridge type injector which is possible to do a vascular injection.

A further object of the invention is to provide an injector which may be re-used only by exchanging the cartridge without disinfection each time.

A still further object of the invention is to provide an injector which could inject almost 100% the medicine contained in the charged cartridge.

Another object of the invention is to provide an injector which never misses a piston.

Other and further objects, features and advantages of the invention will appear more fully from the following description.

FIG. 1 is a vertical cross sectional view of the most preferred embodiment of the invention,

FIG. 2 is a view showing disassembly of the above mentioned embodiment, and

FIG. 3 is an enlarged vertical cross sectional view showing an operation of the embodiment.

As shown, the present invention is substantially composed of a needle portion, an injector tube, a cylinder and a piston. The needle portion has a hollow needle 2 of a desired length extending in opposition to the injecting needle 1, and is provided in ring with a projection 4 within a fitting portion 3 to be engaged with a needle connecting portion 6 of an injecting tube 5. The injecting tube 5 is defined with more than one of concaves 7 and 7a on the connecting portion 6, and is formed with a hollow space 10 to be charged with a film-like cartridge 9 with a sealing cover 8 holding the liquid as shown in FIG. 2. With respect to the injecting needle, the projection 4 engages the concave 7 into restraint, and accordingly the hollow needle 2 is positioned to have its end portion slightly spaced from the sealing cover 8. The piston 11 has an engaging convex 17 on a head 12 thereof, and it makes the head 12 narrower in diameter than an inner diameter of the space 10 over more than 1/2 of the depth of the space 10, and forms a step 13 on a sliding surface following the head 12. The position of the step 13 is restrained at a reduced diameter end opening which defines a stop 15 of a cylinder 14. The cylinder 14 includes a large diameter portion and a small diameter portion. The large diameter portion of cylinder 15 is adapted to be coaxially positioned about the body of the injecting tube 5, and the piston 11 is inserted into the small diameter portion of cylinder 14 from the large diameter portion of cylinder. The small diameter portion has the stop 15 at a circumferential edge of an opening thereof, so that the piston 11 contacts, when moving in opposition, to the step 13 and does not get out from the cylinder 14.

The injector tube 5 is air-tightly mounted with a needle protecting cap 16 on a neck thereof. The cartridge 9 has an engaging concave 18 in correspondence to the engaging convex 17 of the piston 11. The positioning relation of the convex 17 and the concave 18 may be reversed, that is, it is allowable to make a projection on the bottom of the cartridge 9 and makes a recess on the head of the piston 11.

The injector of this invention is constructed as mentioned above, and is set up by positioning the cartridge 9 into the hollow interior 10 of the injector tube 5 having the injecting needle, and inserting and pushing the piston 11 into the cylinder 14 from its large diameter portion until the step 13 contacts the stop 15. Then, the large diameter portion of the cylinder 14 is positioned coaxially of and radially outwardly of the injector tube 5, and the piston 11 pushed slightly so that the convex 17 is engaged with the concave 18 and thus the assembly of the injector is completed (refer to FIG. 1). For performing the injection, the cap 16 is removed and the pressure is effected to the injecting needle 1 toward the tube 5, so that the projection 4 is urged into the other groove 7a from the groove 7, whereby the hollow needle 2 pierces the sealing cover 8 of the cartridge 9 and reaches the liquid agent therein. Then, when pushing the piston 11 on its end portion, the liquid agent in the cartridge 9 goes to the injecting needle 1 through the hollow needle 2. As the piston head 12 is pushing the bottom of the cartridge 9 while the convex 17 is engaged with the concave 18, the cartridge film overlaps by turning over itself (doubles over) and makes a double film, and the liquid agent in the cartridge 9 exhausts all the amount up to its throat. This amount is a predetermined amount. If the piston 11 is moved back just after the injection and since the engagement between the convex 17 and the concave 18 is maintained, the bottom of the cartridge 9 is pulled by the piston 11. Therefore, it is permitted to move back the piston and it is possible to confirm whether the injection is properly made in the blood vessel.

The present invention makes, by one action of fitting the needle, a connection of the liquid agent in the cartridge and the hollow needle and further the injecting needle. Therefore, it is like that the needle goes into Ampulle, and the liquid never touches other members. This is very hygienic and being without disinfection and possible to use it only by charging the cartridge, this is very suitable the urgent occasions in the outdoors, and further the liquid does not leak at all. The invention is much suited to the urgent cases, since it may omit time and steps for conventionally breaking Ampulle at its neck, absorbing the liquid into the injector, expelling the air from the tube and injecting the liquid. The invention does not need to pay attention to the precision of the air-tight sliding between the cylinder and the piston or to the air tight packing of the piston head, and no precision is required to any parts. Also in the instant injector, transparency is preferable, but opacity for heat and light insulation in view of the weather resistibility of the liquid is not impreferable, and it is sufficient to make a mark for the liquid volume at the end of the piston. The cartridge is pushed by the piston and the cartridge film is turned over (doubled over) between the injector tube and the piston head. This condition corresponds to the slide contacting surface between the cylinder and the piston, so that the liquid is all exhausted. Thus, the invention is very useful to calamities such as earthquakes, mountain-climbing, travelling, fire accidents and others. This invention is an excellent injector in safety, stability and function.