DE2335974A1 - Electromechanically driven arm prosthesis joint - friction wheel planetary gearing to worm wheel gearing - Google Patents

Abstract

Electromechanical joint for actuating arm prostheses has the torque of an electric motor mounted in the joint housing transmitted via reduction gearing to the prosthesis. Friction wheel planetary gearing is used, with the pinion on the drive shaft transmitting the torque via sets of gearwheels to a worm wheel drive whose worm wheel is in an adjustable radial-axial bearing. The worm wheel is connected via a coupling with a spindle that is rotatably mounted in the joint housing and holds the prosthesis. The apparatus is compact, noiseless and free from play, with good mechanical efficiency.

Description

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Research laboratory for orthopedic technology Annastift, 3 Hannover-Kleefeld, Heimchenstrasse 1-6

Electromechanical joint

The invention relates to an electromechanical joint, in particular for actuating arm prostheses, the The electric motor mounted in the joint housing transfers the torque to the prosthesis via a reduction gear and other elements transmits.

Pneumatically operated external power joints are known, which, however, are completely inadequate in terms of controllability and energy consumption.

Furthermore, joints of this type are known which work with nickel-cadmium cells. These joints have also changed not proven in practice; the reason for this is the lack of quietness and strong vibrations from the drive.

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The object of the invention is therefore to improve these known joints so that they can be accommodated in a very small space can be, work almost completely noiseless and play-free and also have a very favorable mechanical efficiency own.

This object is achieved according to the invention in that as a reduction gear, a planetary friction gear is provided, the pinion of which is arranged on the output shaft Torque via gear sets on a worm gear transmits that the worm gear of the worm gear in an adjustable Radial thrust bearing is arranged, and that the worm wheel via a coupling with a rotatably mounted in the joint, the Prosthesis-retaining peg is connected.

By using a friction planetary gear as a reduction gear and a worm gear the space requirement of the joint is reduced to a minimum and a low noise level is achieved that is second to none.

The coupling serves as an overload protection.

In a further embodiment of the invention, the planetary friction gear consists of a plurality of bearings around the motor axis Ball bearings, the outer races of which with the motor axis and are in a force-locking connection with a ring that is concentrically and stationary mounted thereon, the ball bearings are mounted in a bearing firmly connected to the output shaft.

In a particular embodiment of the invention Joint with a ball bearing as a radial thrust bearing, the inner race of the ball bearing is in two parts, each of which Part has an inclined running surface along which the balls roll.

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Expediently, one part can be screwed into the other part, with the inclined running surface of one part an annular shoulder of the worm wheel is arranged.

The coupling consists of an elastic ring, which transmits the torque of the worm wheel to a sleeve.

From the physiology of the patient's gait, but also from the point of view of cosmetics, there is a free swinging of the arm joints and such a thing is desirable when walking. The invention meets this requirement due to the fact that pawls pivotable on the sleeve are arranged which can be engaged in recesses which are provided in a collar of the pivot pin. Here is that The torque of the coupling is infinitely variable via a disk that can be adjusted in the direction of the sleeve.

The pawls are under the action of springs that push these pawls into the locking position. A driving pin is arranged on each pawl.

On the pivot is a control disk under the action of a tension spring with outwardly directed lugs provided, wherein a stop is arranged on the nose which cooperates with a counter-stop in such a way that When the collar of the pivot pin rotates, the pawls are unlocked by moving the driver pins along the lugs will.

In order to save power when lifting loads, stands with the sleeve one end of a spring in connection, the other end of which is connected to the joint housing.

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An embodiment of the joint according to the invention is illustrated in more detail below with reference to the drawing. In this show in a purely schematic way:

Fig. 1 is a view of the joint according to the invention, which connects the upper arm with the forearm prosthesis

2 shows a vertical section through the joint according to the invention

FIG. 3 is a view in the direction of arrow A-A in FIG

4 shows a view of the electric motor and a section through the friction wheel planetary gear of the joint according to the invention

FIG. 5 shows a horizontal section along the line II - II in FIG

6 is an isometric illustration on an enlarged scale of the planetary friction gear of the joint according to the invention.

1 with the upper arm is referred to, which is connected to the forearm 2 via the joint 3 according to the invention. It is clear that the joint can also be used advantageously as a shoulder joint and the like; insofar are the arrangement this joint and the type and design of the prosthesis are no limits.

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The joint consists of a housing 4, which in the upper part is roughly cylindrical and the lower part is roughly has the shape of a hemisphere, which closes the housing 4 at the bottom.

A pivot pin 5 is mounted in the housing 4, on which rails 6 sit, which in the embodiment shown carry the forearm 2.

The reference number 7 indicates an electric motor, which transmits the torque to a pivot via a reduction gear and other elements.

As a reduction gear, a planetary friction gear is expediently provided, which is extremely space-saving and is also quiet and also has a very favorable mechanical efficiency.

The friction wheel planetary gear consists of several ball bearings 9 mounted around the axis 8 (Figures 4 and 5), whose outer races 10 with the motor axis 8 and with a concentric to this and stationary ring 11 in frictional connection. The ball bearings 9 are mounted in a bearing firmly connected to the output shaft 10 (FIGS. 4 and 5).

If the motor shaft 8 is set in rotary motion, the ball bearings 9 rotate together with the bearing 13 in a planetary manner around. this axis 8, since the ring 10 is mounted in a stationary manner and therefore cannot perform any rotary movements. In this way, the speed of the motor axis 8 is reduced, so that the Output shaft 12 rotates more slowly.

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On the output shaft 12 sits a pinion 14, which the torque via gear sets 15 to 19 (Figures 2 and 3) transmits to the worm 20 of a worm gear with the worm gear 21.

The worm wheel 21 is mounted in an adjustable radial axial bearing. The inner race is this one Two-part bearing, one part 22 being screwable into the other part. The part 23 forms with the worm wheel 21 a physical unit.

The two parts 22, 23 of the inner race of this Radial axial bearings have inclined surfaces 22a, 23a (Figure 2), along which the balls roll 24, which ring from the outer race 25 are held together. The releasable connection between the parts 22 and 23 can cause signs of wear are taken into account on the inclined surfaces 22a, 23a, so that the required freedom from play is provided.

The worm wheel 21 is connected to the pivot 5 via a coupling 26. The coupling 26 consists of one elastic ring which transmits the torque of the worm wheel 21 to a sleeve 27. The transmitted torque is can be changed via a disk 28 which can be advanced in the direction of the sleeve 27 (FIG. 2).

The coupling 26 serves not only as a transmission element, but also as an overload protection device. If the arm prosthesis is excessively loaded, then the power flow from the drive motor into the prosthesis is interrupted, so that the motor 7 is secured against overload in any case.

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On the sleeve 27 pawls 29 are mounted which are pivotable about pins 30, which are firmly anchored in the sleeve 27 are. These pawls 29 work together with recesses which are incorporated in a collar 32 of the pivot pin 5 are.

The pawls 29 are under the action of springs 33, which strive to the pawls 29 in the To hold the locking position in which they are in the recesses 31 engage positively and non-positively.

A driver pin 34 is arranged on each pawl 29.

On the pivot 5 there is one under the action a spiral spring 35 standing control disk 36 is arranged in which the spiral spring 35 is anchored at one end, while it is at its other end with the pivot 5 in connection.

The control disk 36 has outwardly directed lugs 37 on, of which on the one nose 37 a stop 38 (Figure 3) is provided, which cooperates with a counter-stop 39, which is provided in the housing 4, for example. During the rotational movement of the collar 32 of the pivot 5 in one Direction, the pawls 29 are unlocked by moving the driver pin 34 along the lugs 37.

To relieve the forearm 2 stands with the. sleeve 27 the one end 40a of a spring 40 in connection, the other end 40b of which is connected to the joint housing 4.

The operation of the joint according to the invention is as follows

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Should the forearm 2, for example, move from the extended position into the angular position, that is, in the horizontal direction, upwards are pivoted, then the motor 7 is put into operation, the torque via the reduction gear and the Gears 14 to 19 are transmitted to the worm gear 20, 21, from where the torque is transmitted via the coupling 26 to the sleeve and from there it is transmitted via the pawls 29 to the collar 32 and thus to the pivot 5.

By pivoting the pivot 5, the rails 6 and thus the lower arm 2 are pivoted.

By reversing the direction of rotation of the motor 7, the prosthesis 2 is returned to the extended position.

Should the prosthesis 2 swing freely in the extended position, which is only possible at all because it is from the motor 7 is separated, then the stop 38 strikes against the counter-stop 39 in this particular position. Another Rotary movement of the pivot 5 and thus of the collar 32 in the counterclockwise direction of the arrangement according to FIG. 3 leads to a sliding movement of the driving pin 34 along the corresponding formed lugs 37, so that the pawls 29 against the force of the springs 33 in the unlocked position, so in the Release position are transferred. The connection between the pivot 5 and thus the forearm 2 is in this position as well as the drive completely interrupted. The forearm 2 can therefore oscillate freely in the area of the extended position of the arm.

If the connection between motor 7 and forearm 2 is to be restored, the motor is in the opposite direction Rotated direction so that the stop 38 is released from the counter-stop 39. The control disk 36 with the lugs 37 is supported by springs 35 retracted to its original position and the pawl 29

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with the support of the springs 33 snap into the locking position. This is about the federal government 32 and thus on the Pivot 5 restored the connection to forearm 2.

- patent claims -

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Claims (10)

PATENT CLAIMS 1. Electromechanical joint, especially for operating Arm prostheses, the electric motor mounted in the joint housing transmits the torque to the prosthesis via a reduction gear and other elements, thereby characterized in that a friction planetary gear is provided as a reduction gear, which is on the Output shaft (12) arranged pinion (13) the torque Via gear sets (15 to 19) to a worm gear (20, 21) transmits that the worm gear (21) of the worm gear (20, 21) is arranged in an adjustable radial axial bearing, and that the worm wheel (21) via a coupling (26) is connected to a pin (5) which is rotatably mounted in the joint housing (4) and holds the prosthesis (2). 2. Joint according to claim 1, characterized in that the friction wheel planetary gear from consists of several ball bearings (9) mounted around the motor axis (8), the outer races (10) of which with the motor axis (8) and are in frictional connection with a ring (11) that is concentric to this and fixedly mounted, and that the ball bearings (9) in one with the output shaft (12) firmly connected bearings (13) are mounted. 3. Joint according to claim 1, with a ball bearing as a radial-axial bearing, characterized in that the inner race of the ball bearing is in two parts, and that each part (20, 23) has an inclined surface (22a, 23a) along which the balls roll. 4. Joint according to claim 3, characterized in that one part (22) in the other part (23) can be engaged, and that the inclined running surface (23a) of one part (23) on an annular shoulder of the worm wheel (21) is arranged. - A 2 - ■ 409885 / Ό752 5. Joint according to claim 1, characterized that the coupling (26) consists of an elastic ring, which the torque of the worm wheel (21) on a sleeve (27) transfers, and that on this sleeve (27) pivotable pawls (29) are arranged, which in Recesses (31) can be engaged in a collar (32) of the pivot (5) are provided. 6. Joint according to claim 5, characterized in that g e k e η η ~ ζ eic h η et that the torque of the coupling (26) can be continuously changed via a disk (28) which can be advanced in the direction of the sleeve (-27). ^: 7. Joint according to claim * 5, d a you r c h ge k en η draws, that the pawls (29) are under the action of springs (33) that these pawls (29) "Press into the locking position. 8. Joint according to claim 7, characterized in that on each pawl (29) Driving pin (34) is arranged. 9. Joint according to claim 1 to 8, characterized by a d u r c h that on the pivot (5) a control disk under the action of a spiral spring (35) (36) is arranged with outwardly directed lugs (37), and that a stop (38) is provided on one lug (37) is, which cooperates with a counter-stop (39) in such a way that during the rotational movement of the collar (32) of the pivot pin (5) in one direction unlocks the pawls (29) by moving the driver pins (3 ^) along the lugs (37) will. - A 3 - 40 9885/0752 10. Joint according to claim 1 to 9, characterized in that to relieve the arm prosthesis (2) with the sleeve (27) one end (40a) of a spring (40) is in connection, the other end (40b) with the joint housing (4) is connected. 409885/0752