Hoechst Aktiengesellschaft

Hans-Jurgen Dettbarn

Josef Zimmermann

In this needleless injection instrument, the piston pump (17) for the medium to be injected is connected to a drive motor (18). On the motor housing (1) of the drive motor, an operating element (2) is fitted displaceably and a stroke counter (7) for counting the applications is arranged. To the free shaft end (11) of the stroke counter, a control cam (6) is fixed which engages with a control pin (4) supported on a control roll (3) which is located in the operating element (2) for the drive motor (18).

Needleless injection instrument

In a needleless injection instrument with a removable vaccine pump, the motor housing (1) is provided with a receiving bush (20) which is to receive the vaccine pump. In an opening (7) in the motor housing (1) and the receiving bush (20), a bolt (6) is located which is loaded by a spring (9) and has a nose (5) which engages in a recess (4) in the pump housing (18). The motor housing is also provided with a displaceable operating element (8), to which the bolt (6) is connected and which has a recess (11) for receiving a locking device (14). The locking device (14) is fixed by means of a leaf spring (13) to the motor housing; it can engage either in a groove (15), located in a spring housing (17) provided in the motor housing, or in the recess (11) of the operating element (8).

Locking mechanism for the removable vaccine pump of a needleless

In this piston pump, the pump housing (1) is provided with a mounting (E) for a vessel (3), which consists of a pipe end (4) provided with a hollow needle (5) and of a connecting element (9, 16, 17) for connecting the vessel (3) to the pipe end (4). The pump housing (1) has an inlet channel (7) which is connected to a channel (6) in the pipe end (4). So that the vessels (3) can be connected rigidly to the piston pump, the connecting element consists, for example, of a metal sheet (9) bent in the form of a U, which is provided on its inner side with U-shaped yokes (10, 11), the yoke (10) facing the pump housing (9) engaging into a groove (12) provided in the pipe end (4) and the other yoke (11) serving for surrounding the vessel neck.

Piston pump for needle-less injection instruments

In this injection instrument, the piston pump (A) is connected to a drive motor (B), the working piston (5) of which is arranged displaceably in a cylindrical bore (6) of the motor housing (1). To ensure that, in the case of different piston strokes of the piston pump (A), the pump pressure remains the same and, on the other hand, injection can be effected only when the instrument rests on the skin, the drive motor (B) is provided with a spring housing (3) in which is located a working spring (2) which is supported at one end on a supporting face (18) in the spring housing (3) and at the other end on an end face (9) in the motor housing (1) and is guided by a part of the working piston (5) designed as a piston rod (4). To retain the tensioned working piston (5), the spring housing (3) is provided with a recess (11) for a pawl (10) which is supported by a bolt (13) arranged displaceably in the motor housing (1).

Needle-less injection instrument

In this injection instrument, the piston pump (A) is connected to a drive motor (B), of which the working piston (5), supported on a working spring (2), is arranged displaceably in a cylindrical bore (6) of the motor housing (1). A pressure chamber (7) which has supply devices (3, 8) and discharge devices for the pressure medium is formed in the bore (6). The working spring (2) is held in a tensioned position by a pawl (10) supported by a bolt (13), the bolt (13) being supported on an operating element (C). So that injection can be initiated only when the nozzle (23) is pressed onto the subject, the bolt (13) is connected rigidly to the operating element (C), and its free end is arranged displaceably in the motor housing (1).

In this injection instrument, the piston pump (A) is connected releasably to a drive motor (B), the working piston (5) of which is arranged displaceably in a cylindrical bore (6) of the motor housing (1). So that the piston pump (A) can be coupled to and uncoupled from the drive motor (B) by simple manipulations under sterile conditions and so that a ram play independent of the particular piston stroke is present between the piston pump and drive motor, the pump housing (20) has on the pump head (17) an annular groove (18) and a pair of flattened portions (22, 23) which are parallel to one another and reach to the bottom of the annular groove (18). The pump plunger (2) on the peg (8) projecting from the pump chamber (7) of the pump housing (20) is provided with two equally deep annular grooves (9, 10) located next to one another and with two pairs of flattened portions (11, 12, 13, 14) which are each parallel to one another and which reach to the bottom of the annular grooves (9, 10), one pair of flattened portions (11, 12 or 13, 14) extending only from the annular groove (9) to the annular groove (10 ) and being arranged perpendicularly to the second pair of flattened portions. Two pins (15, 16, 27, 28) are arranged, parallel to one another, respectively in the motor housing (1) and in a bore (19) in the piston shaft (4) and engage into the annular groove (18) of the pump housing (20) and the annular grooves (9) and (10) of the pump plunger (2). The pump plunger (2) and the piston shaft (4) are provided with devices preventing them from rotating in their housings.

In this injection instrument, the piston pump (A) is connected to a drive motor (B), of which the working piston (5) supported on a working spring (2) is arranged displaceably in a cylindrical bore (6) of the motor housing (1). A pressure chamber (7) which has supply devices (3, 8) and discharge devices (4, 9) for pressure medium is formed in the bore (6). To ensure that the pressure medium cannot be simultaneously supplied to and discharged from the pressure chamber (7), there is a control shaft (37) which is assigned to valves (8 and 9). The control shaft (37) is provided with a lever (38) and has segment-like recesses (39, 40) which interrupt the engagement of the valves (8, 9) with the control shaft (37). The recesses (39, 40) are arranged on the control shaft (37) so that the valves are not engaged simultaneously with the control shaft (37).

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Marburg, Germany

Hans-Jurgen Dettbarn