RU2254831C1 - Artificial knee joint provided with braking mechanism - Google Patents

Abstract

FIELD: medical engineering.

SUBSTANCE: device has femur part and crural part connected to each other with rotation mechanism. Braking mechanism, mounted in the knee joint on its axle, has compression unit and unit for controlling the compression force composed of an elastic member and adjusting screw. Threaded hole for receiving the screw is available in one of the parts. The braking mechanism has lubrication unit enveloping the compression unit and is engageable with the axle.

EFFECT: wide range of exoprostheses rehabilitation applications; simplified design; high design reliability.

6 cl, 5 dwg

Description

The invention relates to medical equipment, namely to artificial knee joints, and can be used when prosthetics of the lower extremities.

It is known that the absence in the artificial knee joint (hereinafter - ICS) of means for controlling the phase of transfer leads to problems when walking on the hip prosthesis. After the back push, the heel of the prosthesis rises higher than that of a healthy leg, which lengthens the transfer time of the prosthetic limb and aggravates the asymmetry of movements. In addition, at the end of the transfer phase, there is a strong collision of the recurrence elements of the ICS, leading to a tendency for the receptacle sleeve to fall off the stump and to a poorly dynamic shock, which, after prolonged use, has a negative effect on the health of the disabled person (see, e.g., R. Baumgartner, P. Botta Amputation and prosthetics of the lower extremities. Translated from German.M .: Medicine, 2002).

The presence in the ICS of the means providing control of the transfer phase, namely, the mechanisms of braking of the lower leg, eliminates excessive bending of the prosthesis in the phase of transfer and reduces the impact on the elements of the ICS from the inertial forces of the lower leg and foot at the time of complete extension of the prosthesis. This allows you to bring the time of transfer of the prosthetic limb closer to normal, reduce dynamic asymmetry, reduce energy consumption and reduce discomfort when walking a disabled person (B.S. Farber et al. Theoretical foundations for constructing lower limb prostheses and movement correction. Edited by B.S. Farber, book 2. M .: TsNIIPP, 1994).

There are various schemes for constructing such mechanisms. For example, an ICS of the thigh with a braking device is known (SU 0240178, Klimov et al., March 21, 1969), in which the function of adjustable braking is realized by means of a regulator made in the form of a friction earring and a screw built into the ICS. In another invention, a hip prosthesis that implements the specified function, the lower leg is braked by creating friction between the movable and fixed elements placed on one of the hinge axes (SU 0288858, Klimov et al., 08/12/1970). In another device (RU 2043091 C1, Jacobson et al., September 10, 1995), the 4-axis IKS is braked by means of friction and elastic washers, the compression force of which is regulated by a screw between them. In the well-known 4-axis IKS (models 3R20 and 3R36 of the company "Otto Bock", see technical description 647G72-3000-05.00-MD), another mechanism for regulating the force of braking of the lower leg is introduced. This device combines the braking and rotation mechanisms, however, during dynamic walking, rapid wear of the conical sliding-friction surfaces occurs, which leads to a decrease in braking forces, which requires additional regulation during operation and can lead to premature disruption of the ICS performance.

The closest analogue to the patented one is ICS, containing the femoral and lower leg parts, interconnected by a rotation mechanism having at least one axis, and a braking mechanism mounted on the axis inside the joint and including a crimping element and a compression force control unit, including an adjustment screw, moreover, the threaded hole for the screw is located in one of the mentioned parts (SU 0164098, Plotnik, 08/25/1964). However, when the rotation and braking mechanisms are combined, the sliding-friction surfaces perceive both internal and external loads (cyclic - from the weight of the disabled person and the weight of the prosthesis, shock - from the inertial forces arising at the time of complete extension of the prosthesis, and others). Dry friction contributes to the wear of contacting surfaces, since all of the above devices, including the closest analogue, do not provide elements for lubricating sliding-friction surfaces. In addition, at each step, at the time of the transition of the ICS from the rest state to the state of rotation, a “breakdown” occurs, which is felt by the disabled person as discomfort when walking, which is also associated with “dry” friction, in which, as you know, the coefficient of rest friction is much higher slip friction coefficient.

The objective of the present invention is the creation of ICS with a braking mechanism without these drawbacks, namely, free from external loads and not requiring additional regulation associated with the wear of rubbing surfaces during operation.

The technical result of the invention is improving rehabilitation capabilities, ease of use, simplicity and reliability of the structure is achieved by the fact that the artificial knee joint contains the femoral and lower leg parts, interconnected by a rotation mechanism having at least one axis, and a braking mechanism. The braking mechanism is installed inside the joint on the axis and includes a crimping element, lubrication units and adjusting the compression force. The unit for controlling the compression force is made in the form of an elastic element and an adjusting screw, while the screw hole for the screw is located in one of the mentioned parts, and the lubrication unit covers the crimp element and is in contact with the axis.

The joint can be characterized by the fact that the crimping element is made in the form of two blocks with tightening screws, as well as the fact that the crimping element is made in the form of a split sleeve.

The joint can also be characterized by the fact that the lubrication unit contains an oil-containing element in the casing and wicks in the form of washers mounted on an axis.

The joint can also be characterized by the fact that on the outer surfaces of the pads perpendicular to the axis of the adjusting screw, support pads are made located on both sides of the groove for the screw and in the direction of the axis of the rotation mechanism, and the width of the pads is less than the width of the groove.

The joint can be characterized, in addition, by the fact that on the outer surfaces of the split sleeve perpendicular to the axis of the adjusting screw, support pads are made located on both sides of the groove for the screw and in the direction of the axis of the rotation mechanism, and the width of the pads is less than the width of the groove.

The invention is illustrated in the drawings, where:

in FIG. 1 shows the design of the IKS with a braking mechanism;

figure 2 is the same as in fig. 1, a section along AA;

figure 3 - the braking mechanism in a disassembled state;

figure 4, 5 - embodiments of the crimp element.

The principles of the invention are disclosed in the following example of a four-axis IKS and can be applied both in mono-and in polycentric IKS of various modifications.

IKS contains two main components: the femoral part 10, which in the manufacture of the prosthesis is connected to the receiving sleeve of the thigh, and the lower part 12, connected to the artificial lower leg. Parts 10 and 12 are interconnected by a rotation mechanism 13 including an axis 14 and links 16. The axis 14 is mounted in the housing 18 of the femoral part 10 on bearings 20 and is fixedly connected to the links 16.

The braking mechanism 21 (Figs. 3, 4) is a crimping element 22 that spans the axis 14 and is made in the form of pads 24 and 25, tightened on one side by screws 28, and on the opposite side through an elastic element 30 and a washer 31 with an adjusting screw 32. The threaded hole for the screw 32 can be made either in the intermediate sleeve 34, fixedly connected to the housing 18, or directly in the housing 18. The elastic element 30 can be made in the form of a set of Belleville springs, screw compression springs, bushings of elastic material and other like lementov. On the surfaces of the pads 24, 25 there are support pads 36, 37. The pads 36, 37 are located on both sides of the groove 33 in the direction of the axis 14. The width of the pads 36, 37 is less than the diameter of the screw 32. This design prevents the occurrence of bending moment acting on the screw 32 , and also contributes to the stability of the regulatory characteristics in serial production.

The braking mechanism 21 has a lubrication unit consisting of an oil-containing element 40 and two wicks-washers 42, pressed against the crimping element 22 by means of a casing 44 and washers 46, respectively. As another form of execution of the crimping element 22, it is possible to use a split sleeve 48 (Fig. 5) with bearing pads 50 and 51. The compression force of the sleeve 48 is controlled through the elastic element 30 with a screw 32.

When walking on the prosthesis, the axis 14 rotates in the housing 18 on the bearings 20. The crimping element 22 - pads 24, 25 (Fig. 4) or a split sleeve 48 (Fig. 5) - compresses the axis 14 with a certain force, the value of which is set by the adjusting screw 32 with individual adjustment of the prosthesis. For weakened people with disabilities who have a slow pace of walking, the compression force is set small, and for energetic - significant. To eliminate “dry” friction, the contacting surfaces are lubricated with wicks-washers 42 from the oil-containing element 40.

In the patented device, in contrast to the closest analogue, the rotation and braking functions are implemented by various mechanisms that are not related to each other. Therefore, the braking mechanism does not perceive external loads (cyclic, due to the weight of the disabled person, shock from inertial forces and others). Patented design with practical prosthetics will facilitate the processes of individual adjustment and regulation of ICS, which makes it possible to reduce the dynamic asymmetry of walking on the prosthesis and reduce the energy consumption of a disabled person.

Claims (6)

1. An artificial knee joint containing the femoral and lower leg parts, interconnected by a rotation mechanism having at least one axis, and a braking mechanism mounted on the axis of the joint and including a crimping element and a compression force control unit, including an adjusting screw, and a threaded one the screw hole is located in one of the mentioned parts, characterized in that the braking mechanism includes a lubrication unit, covering the crimp element and in contact with the axis, and a force control unit Compression includes an elastic element. 2. The joint according to claim 1, characterized in that the lubrication unit contains an oil-containing element in the casing and wicks in the form of washers mounted on an axis. 3. The joint according to claim 1, characterized in that the crimp element is made in the form of two pads with tightening screws. 4. The joint according to claim 3, characterized in that on the outer surfaces of the pads perpendicular to the axis of the adjusting screw, support pads are made located on both sides of the screw groove and in the direction of the axis of the rotation mechanism, and the width of the pads is less than the width of the groove. 5. The joint according to claim 1, characterized in that the crimp element is made in the form of a split sleeve. 6. The joint of claim 5, characterized in that on the outer surfaces of the split sleeve perpendicular to the axis of the adjusting screw, support pads are made located on both sides of the screw groove and in the direction of the axis of the rotation mechanism, and the width of the pads is less than the width of the groove.

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