DE9320853U1 - Prosthetic joint - Google Patents

Description

The invention relates to a prosthetic joint, in particular a knee or hip joint, with an upper joint part, a lower joint part, a pivoting joint connecting these two joint parts to one another and connected to a joint part in a rotationally fixed manner.
Joint axis and damping of the joint pivoting.

It is known to hydraulically dampen a knee joint. For this purpose, a hydraulic damping cylinder is provided which is arranged outside the joint and which is connected with one end to
is hinged to the lower part of the joint and acts with its piston rod on a lever connected to the upper part of the joint.

15 The prosthetic joint described above can be seen in a design as a brake knee joint for thigh prostheses from DE-OS 1 766 309. This involves a slotted brake bush made of elastic material, which
on its slotted side an upper and a lower

20 attachment and includes an axis fixed against rotation in the lower leg part of the prosthesis along its entire length.

Theodor-Heuss-Straße 1 D-38122 Braunschweig Federal Republic of Germany

Telephone 0531 / 8 00 79
Telex 0-9 52 620 gramm d Fax 0531 / 8 12 97

There is a pin connected vertically to the lower attachment, which is inserted into a recess in the knee joint body. When the knee joint body is loaded, the pressure is transferred to the upper attachment of the brake bush.

DE-AS 1 903 248 discloses a knee joint for leg prostheses, with a brake controlled in the height direction under the influence of the successive loading and unloading, using a wedge that influences the braking on one leg part and is carried by the other leg part. This wedge is held by one leg part so that it can be turned but moved in height between corresponding inclined surfaces of two brake segments, the curved surfaces of which, in their locked position, rest against a hollow brake cylinder in the other leg part.

EP 0 097 226 A1 discloses a knee joint with a joint axis, around which an upper joint part can be rotated relative to a lower joint part, and with a hydraulic damping cylinder mounted between the upper joint part and the lower joint part, which is mounted in the fork-shaped lower joint part.

DE 30 28 608 Al contains an artificial leg with hydraulic pendulum and stance phase control for thigh amputations as well as knee and hip joint disarticulations. A single-axis knee joint is provided with a double-acting hydraulic cylinder hinged behind the knee pivot point, which, with just one piston and one working cylinder, simultaneously controls the bending and stretching movement of the lower leg in the pendulum phase and the stance phase of the prosthesis and takes over the function of the knee joint stop.

The invention is based on the object of improving the construction described at the outset, in particular with regard to its function.

This object is achieved according to the invention by the following features

solved:

a) The damping is integrated in one of the two joint parts and acts directly on the joint axis which is connected to the joint part in a rotationally fixed manner;

b) the damping has a closed displacement chamber which at least partially concentrically encloses the joint axis over its circumference and which is divided into two sub-chambers by the joint axis designed as a rotary piston;

c) the sub-chambers of the displacement chamber are connected to each other via two parallel, opposing throttle check valves;

d) Both throttle points can be controlled separately from the outside.

The construction according to the invention, when designed as a knee joint, enables swing phase control in addition to the known braking knee, in which the pivoting resistance can be adjusted separately with regard to flexion and extension.

The throttles can basically be controlled mechanically or by electrical actuators. According to the invention, it is advantageous if the throttle is controlled by an axially movable throttle rod, the displacement of which can be carried out, for example, by a manually adjustable knurled screw.

Particularly in the case of a prosthetic joint designed as a knee joint, it is advantageous if a force exerted on the joint causes a predefined closing of the flexion throttle. This can be designed in the form of a telescopic, force or torque control.

The rotary piston preferably has a rectangular piston plate that rests on the two end faces and the cylindrical inner wall of the closed displacement chamber via a sealing frame. This can preferably be secured by a retaining piece screwed to the piston plate. This results in a displacement chamber that is closed on all sides with a single, defined leak provided in the area of the rotary piston seal. It is advantageous if the rotary piston seal that seals the displacement chamber to the outside is located outside the rotary piston bearing. The rotary piston bearing is lubricated by the excess pressure in the displacement chamber, i.e. by the hydraulic oil, which should therefore have good lubricating properties.

Further features of the invention are the subject of the subclaims and are explained in more detail in conjunction with further advantages of the invention using an embodiment.

The drawing shows an exemplary embodiment of the invention. It shows:

Figure 1 - a knee joint in side view;

Figure 2 - the representation according to Figure 1 in front view;

Figure 3 - the representation according to Figure 1 in plan view;

Figure 4 - a longitudinal section along the line AA in Figure 2;

Figure 5 - a longitudinal section along the line CC in Figure 2 and

Figure 6 - a cross section along the line BB in Figure 1.

As an example of a prosthetic joint, a knee joint is shown, which consists of an upper joint part 1 and a lower joint part 2 arranged somewhat eccentrically to it. The pivotable connection of both joint parts 1, 2 is made via a joint axis 3 that is connected to the upper joint part 1 in a rotationally fixed manner. The upper joint part 1 rests with its partially cylindrical underside on the cylindrical surface 4 of the lower joint part 2. Due to the eccentric arrangement to one another, when the joint is pivoted, the upper joint part 1 runs with its underside onto the cylindrical surface 4, which thus serves as a joint stop over its entire surface. A separate joint stop can therefore be omitted.

To dampen the pivoting of the joint, in the embodiment shown, hydraulic damping is integrated directly into the joint lower part 2, which acts directly on the joint axis 3. The hydraulic damping comprises a closed displacement chamber 5 which partially concentrically surrounds the joint axis 3 over its circumference and which is divided into two sub-chambers 5a, 5b by the joint axis 3 designed as a rotary piston. For this purpose, the joint axis 3 is equipped with a rectangular piston plate 6 which extends in the axial and radial direction and which has its two radially extending end edges on the two end walls of the displacement chamber 5 and its axially extending longitudinal edge on the cylindrical inner wall of the displacement chamber 5. This sealing is preferably carried out via a sealing frame 7 which is attached to the piston plate 6 by a retaining piece which is screwed to the piston plate 6 and is not shown in detail in the drawing.

The displacement chamber 5 is sealed to the outside by a rotary piston seal 8, which is located outside the rotary piston bearing 9. Lubrication is carried out by the overpressure prevailing in the displacement chamber 5, whereby the displacement chamber 5 is pre-

preferably filled with a hydraulic oil with high lubricating properties.

The partial chambers 5a, 5b are connected to one another via two parallel, oppositely acting throttle check valves 10. The latter are arranged in two holes 11 next to one another in the lower joint part 2, which run perpendicular to the joint axis 3 and are each closed off from the outside by a sealing plug 12.

To control the throttle point of each throttle check valve 10, a throttle rod 13 is provided in the illustrated embodiment, which can be moved lengthwise by means of an adjustment device (not shown in detail), for example a manually operated knurled screw, and whose upper free end (shown in Figure 5) extends more or less deeply into the flow cross-section of the flow connection between the two partial chambers 5a and 5b. The possibility of separately adjusting the two throttle rods 13 means that the swivel resistance can be adjusted separately for flexion and extension. It is also advantageous if a load on the knee leads to the flexion throttle closing. This is achieved by means of a telescopic, force or torque control (not shown in detail in the drawing).

Claims (10)

Prosthetic joint, in particular knee or hip joint, with an upper joint part (1), a lower joint part (2), a joint axis (3) pivotably connecting these two joint parts (1, 2) to one another, connected in a rotationally fixed manner to a joint part (1), and a damping of the joint pivoting, characterized by the following features: a) The damping is integrated in one (2) of the two joint parts (1/2) and directly acts on the joint axis (3) which is connected to the joint part (1) in a rotationally fixed manner; b) the damping has a closed displacement chamber (5) which at least partially concentrically encloses the joint axis (3) over its circumference and which is divided into two sub-chambers (5a, 5b) by the joint axis (3) designed as a rotary piston (3, 6, 7); Theodor-Heuss-Straße D-38122 Braunschweig Federal Republic of Germany Telephone 0531 / 8 00 79 Telex 0-9 52 620 gramm d Fax 0531 / 8 12 97 c) the partial chambers (5a, 5b) of the displacement chamber (5) are connected to one another via two parallel-connected, oppositely acting throttle check valves (10); d) Both throttle points can be controlled separately from the outside. 2. Prosthetic joint according to claim 1, characterized in that the control of a throttle point is carried out by an axially displaceable throttle rod (13). 3. Prosthetic joint according to claim 2, characterized in that a manually adjustable knurled screw or the like is provided for displacing the throttle rod (13). 4. Prosthetic joint according to claim 1, 2 or 3, characterized in that a force loading the joint causes a predefined closing of the flexion restriction point. 5. Prosthetic joint according to one of the preceding claims, characterized in that the rotary piston (3,6,7) has a rectangular piston plate (6) which rests on the two end faces and the cylindrical inner wall of the displacement chamber (5) via a sealing frame (7). 6. Prosthetic joint according to claim 5, characterized in that the sealing frame (7) is fixed by a holding piece screwed to the piston plate (6). 7. Prosthetic joint according to one of the preceding claims, characterized in that the rotary piston seal (8) sealing the displacement chamber (5) to the outside is located outside the rotary piston bearing (9). 8. Prosthetic joint according to one of the preceding claims, characterized in that for mounting the two throttle check valves (10) in the joint part (2) receiving the displacement chamber (5) two bores (11) are provided, which are closed to the outside by a sealing plug (12). 9. Prosthetic joint according to one of the preceding claims, characterized in that the damping medium is a hydraulic oil with high lubricating properties. 10. Prosthetic joint according to one of the preceding claims, characterized in that the joint upper part (1) is supported with its partially cylindrical underside on the cylindrical surface (4) of the joint lower part (2) arranged eccentrically to the joint upper part. Patent attorneys
Gram + Lins
Gr/is