US2705953A - Hypodermic injector - Google Patents

Description

April 1955 H. POTEZ HYPODERMIC INJECTOR Filed June 24, 1953 lzzv 612601 y fzTPozbez United States Patent HYPODERMIC INJECTOR Henry Potez, Paris, France, assignor to Laboratoire dHygiene Scientifique Hygiscient, Paris, France, a French company Application June 24, 1953, Serial No. 363,718

Claims priority, application France November 24, 1952 4 Claims. (Cl. 128-173) This invention relates to hypodermic injectors of the type comprising a small incorporated pump adapted to project, through a tiny outlet, a liquid to be hypodermically injected, with a suflicient pressure to cause said liquid to puncture the skin of a patient and enter the tissue tlherebeneath, without requiring the use of a hollow need e.

The main object of my invention is to provide a hypodermic injector of this type provided with incorporated electro-magnetic vibrating means operatively connected with the piston of said pump.

This arrangement permits injecting a dose as important as desired without any straining of the operator.

A further object of the invention is to equip such an electro-magnetically controlled hypodermic injector with a detachable container, such as a conventional syringe, removably secured thereon. There is thus obtained a portable self-contained injector.

A further object of my invention is to provide a hypodermic injector of the type described, the incorporated pump of which is so designed as to permit alternative sucking of the liquid into the externally supported container and forcing of said liquid through the injecting outlet under the convenient pressure, without including the usually required sucking and exhaust valves.

With these and other objects in view, the invention will be better understood from the following description with reference to the accompanying drawings illustrating some embodiments of the invention.

In these drawings:

Fig. 1 is an axial longitudinal sectional view of an electro-magnetically controlled hypodermic injector according to the invention, and

Figs. 2, 3 and 4 show diagrammatically three variations of the electromagnetic vibrator.

The hypodermic injector according to the invention, as shown in Fig. 1 comprises a casing including a body 1 in which are mounted the operating members and an injection head 2 screwed in body 1 and fitted with a nipple 3 adapted to be supplied, for instance, through a flexible conduit or hose 4 from an outer dosing vessel such as syringe 5.

The nipple 3 communicates through a duct 6 with an axial cylindrical feed chamber 7 that communicates in turn with a delivery chamber 8 also cylindrical in shape and axially arranged, but having a smaller diameter than chamber 7 and the outer end of which leads to a minute calibrated hole 9 adapted to ensure the injection into the patients tissues of liquid from syringe 5. In order to facilitate the dismounting of and the access to the various chambers and passages, the head 2 is made of three parts screwed in one another, the outlet 9 being provided in a pointed part 10 that is intended to be applied upon the patients epidermis. 11 designates a piston member that sucks the liquid from the vessel 5, when it moves from the left hand side to the right hand side (when referring to Fig. 1) and which forces this liquid into the chamber 8 and thence, through the calibrated outlet 9, when it moves in the reverse direction. The piston 11 is guided in an axial bore provided in the head 2 and is formed with an internal head 37 which is permanently held by a spring 38 in bearing engagement against a rod 39, the inner end of which is secured to the armature 12 of an electro-magnet 28 by means of a nut 13 screwed on a threaded portion 14 of said rod 39. Two discs 15 and 16 are also secured to the rod 39; they are screwed on threaded portions 17 and 18 of the rod 39 having equal and opposite pitches. The two discs 15 and 16 are, moreover, guided along rods 19. Two opposite springs 20 and 21 are in bearing engagement at their outer ends with the discs 15 and 16, respectively and at their inner ends with the respective faces of an intermediate annular flange 22. The annular flange 22 is supported, on one hand, by a smooth rod 23 along which it is adapted to slide freely and on the other hand, by a threaded rod 24 which is screwed in an innerly threaded hole of the annular flange 22. The threaded rod 24 may be adjusted from the exterior through its sunk head 25 and may be secured in any position of adjustment by means of a set screw 26. Similarly, the rod 39 may be adjusted from the exterior by means of its slotted end 27. The adjustment of the threaded rod 24 makes it pos sible to vary the neutral position of the annular flange and therefore the air-gap between the armature 12 and the electro-magnet core 28. The adjustment of the opposite hands threaded portions 1718 on the rod 39 makes it possible to vary the interval between the two discs 1516 with respect to the intermediate flange 22 and therefore, the stress of the compression springs 20-21.

In the example illustrated in Fig. 1, the electro-magnet 28 which operates the vibrating assembly consisting of the armature 12, the rod 39 and the elastic system 20-21, is of the type having a cylindrical core E-shaped in axial section and the armature 12 of which recipro cates in a parallel translatory motion.

In the modification illustrated in Fig. 2, the electromagnet 28a is provided with an L-shaped armature 12a pivoted as at 29 and the shorter leg of this armature is permanently urged towards its middle position by the resilient assembly consisting of two opposite compression springs 38a21a. The adjustment of the stress of these two springs and, hence, of the air-gap, is ensured in this instance by a knurled thumb nut 30 which cooperates with a threaded rod 39a rigid with the magnetic core 28a. The head 37 of the piston 11 of the pump which is incorporated in the injection head 2, the feeding nipple 3 of which is diagrammatically shown in this figure as at 3, is permanently held in bearing engagement with the shorter leg of the armature 12a by the action of spring 38a.

In the modification illustrated in Fig. 3, the electromagnet 28b is of the U-shaped core type and its armature 12b is floatably mounted between two springs 38b and 21b; the air-gap is adjusted in the same manner as in the embodiment of Fig. 2, by means of a knurled thumb nut 30b which cooperates with the threaded end of the rod 3% which is rigid with the magnetic core 28b. In this modification, when the electro-magnet 28b is energized, the armature 12b first comes to rest in the vicinity of its lower end against the core of the electromagnet and then vibrates on its bearing point.

Finally, in the modification of Fig. 4, the electromagnet has an E-shaped core and the armature is suspended as in Fig. 3 between the springs 21c and 38c, the whole assembly being arranged in such a manner that the delivery stroke of the piston is effected under the action of the electro-magnet and not by the spring recoil as in Fig. 3. The adjustment of the air-gap is effected in the same manner as in the preceding instance by means of a knurled thumb nut 36c which cooperates with a threaded rod 39c rigid with the magnetic core 28c.

In the embodiment shown in Fig. l, the hypodermic injector is designed in the shape of a pistol the handgrip 33 of which contains a switch 34 operated by a triggerlike part 35. The electromagnet 28 is energized through the switch 34 from the pins 36 on which a female connector may be plugged.

It is to be noted that the pump device incorporated in the injection head 2 needs no obturating member, neither for sucking nor for delivering. Actually, when the pointed nozzle is applied against the skin, the latter obturates the calibrated aperture 9 thus serving as a delivery valve or flap. Moreover, during the delivery stroke, the outer end of the piston 11 enters the compression chamber 8 and from this moment on the volume of this piston contained in the feed chamber 7 does not vary any more, so that, the liquid has no tendency to be 3 forced back through duct 6 toward the vessel 5. A delivery valve consequently may be also dispensed with.

Furthermore, the suction is also efficient when the injector is not applied on the skin of the patient, due to the tiny diameter of outlet 9 causing a loss of pressure which is sufliciently important to act as an exhaust valve.

It is to be understood that the invention is by no means restricted to the embodiments or the constructional features represented and/ or described; it may undergo many modifications as usual in the art according to the application contemplated. Particularly, the design and the number of the electromagnets which operate the pump, the construction of the vibrating system which cooperates with this or these electromagnets, the members for feeding the liquid, adjusting and controlling members, may vary between wide boundaries, without departing from the scope of the invention.

The apparatus which has been described is energized with alternative current. It is obvious that usual means to feed it with direct current may be provided if desired.

The cylinder might be possibly connected to the feed chamber through orifices provided through its wall. In this case the piston would close or open the orifices in suitable positions of its stroke to allow the liquid to be introduced at the right moment into said cylinder.

What is claimed is:

1. A hypodermic injector comprising, in combination, a casing having one end provided with a tiny injection outlet, a pump cylinder in said casing communicating With said outlet and having an inlet, a piston member operatively associated with said pump cylinder, said pump cylinder comprising a first chamber adapted to receive said piston member with an annular space therebetween provided with said pump inlet, a second chamber in alignment with and adjacent to said first chamber communicating with said injection outlet and adapted to receive said piston member with a tight sliding fit, said piston member being positioned with respect to said chambers so as to be adapted to alternately enter said chamber through said first chamber and to recede from said second chamber as said piston reciprocates, a container for containing liquid to be hypodermically injected, means to removably secure said container on said casing outside the same, means to communicate said container with said pump inlet, eleetro-magnetic vibrating means in said casing operatively connected with said piston member and means including a control switch to feed said electromagnetic vibrating means from a suitable source of alternating current.

2. In an electrically operated hypodermic injector device including a pump and electromagnetic means for actuating said pump, a casing enclosing said electromagnetic means, a pump cylinder located at one wall of said casing and having two length portions separated by a cylinder space of larger inner diameter than that of said length portions, one of said cylinder portions being provided with a minute discharge aperture, a piston guided for reciprocating movement in the other length portion of said cylinder and actuated by said electromagnetic means so as to move through said larger cylinder space into or out of said apertured length portion, and an inlet duct communicating with said larger cylinder space, the crosssectional area of said discharge aperture being sufiiciently small to permit said piston to suck liquid medicament through said inlet duct into said larger cylinder space as the piston moves from the apertured cylinder length portion through said larger cylinder space and to expel the medicament from said larger cylinder space exclusively through said aperture as the piston moves into the apertured cylinder length portion towards said aperture.

3. A hypodermic injector according to claim 1 further comprising means for adjusting the air-gap of said electromagnetic vibrating means.

4. A hypodermic injector according to claim 1, wherein said vibrating means includes a resiliently and adjustably supported vibrating member, said piston member being directly secured to said vibrating member.

References Cited in the file of this patent UNITED STATES PATENTS 2,550,053 Ferguson Apr. 24, 1951 2,568,757 Mesh Sept. 25, 1951 2,648,017 Ziherl Aug. 4, 1953 FOREIGN PATENTS 1,041,887 France June 3, 1953

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