JPS6153061B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows changes in the posture of the right side of the body during one walking cycle, that is, from the landing A of the right foot to the next landing M. A-I
The period between I and M is the supporting phase, and the period between I and M is the floating phase. An ideal prosthetic leg would be one that allows such changes in posture.

As can be seen in Figure 1, when a healthy person walks, the knees are greatly bent before entering the floating phase, and once the foot is in the floating phase, the legs below the knees are swung forward. A prosthetic leg that can perform movements similar to this has a structure that allows the thigh and lower leg to rotate freely relative to each other. However, with such a prosthetic leg, if you try to bend the knee like between A and G during the supporting leg phase, the knee will suddenly break due to the load from the upper body, so it is necessary to take steps to prevent this from happening. Currently, they are learned through training. Therefore, I don't like the risk of knee bending,
Prosthetic legs are often used that keep the knee extended when walking, but this makes it extremely difficult to walk on slopes or stairs. Additionally, there are several types of prosthetic legs that have a friction brake mechanism that attempts to prevent the knee from buckling due to the load applied to the knee, but the braking force of these is too weak to rely on. In contrast, the knee joint mechanism of the present invention has a braking force that can support the knee no matter how greatly it is bent.

FIG. 2 shows a conventional friction brake mechanism that is the starting point of the present invention, and its principle will be explained. The thigh connecting part 3 and the tightening part 5 are connected by a shaft 1, and the shaft 2, which is fitted into a hole at the left end of the tightening part 5, is fixed to the lower leg 6. Axis 2 becomes the knee joint axis. When a load from the upper body is applied to the knee, the thigh connecting part 3 tries to rotate around the axis 1, presses the upper part of the fastening part 5 via the spacer 4, and as a result tries to pull up the lower part. This causes the clamping part 5 to clamp the shaft 2. The braking force around axis 2 generated by this force prevents the knee from buckling.
The braking force increases regardless of whether the clamping force is increased or the diameter of the shaft 2 is increased. However, if the shaft 2 is made larger, the cross-sectional area of the dotted line portion 5a on the left side of the shaft 2 becomes smaller and breaks. Moreover, even if the tightening force is increased, it will break at the dotted line portion 5a. In order to cope with this, increasing the strength of the dotted line portion 5a reduces the deformation and reduces the tightening force. For the above reasons, Figure 1
This mechanism cannot provide sufficient braking force.

The present invention eliminates the above drawbacks, and its structure is shown in FIGS. 3 and 4. The tightening parts are divided into upper and lower parts 5.1 and 5.2, which are connected by a shaft 10. Instead of the shaft 2, two friction disks 2a with large diameters are placed on the inside and outside of the knee. This mechanism has nearly 10 times the braking force of the mechanism shown in Figure 2. Therefore, no matter how much you bend your knees, your knees will not bend. Thereby, the spacer 4 can be used instead of the elastic body 4a to approximate the bending and stretching motion of the knee between A and E in FIG. In other words, if the load from the upper body is suddenly applied when landing on the floor,
The femoral connection 3 rotates around the axis 2 and tries to pull up the lower clamping part 5.2 via the axis 1 while compressing the elastic body 4a. At the same time, the elastic body 4a presses down on the upper clamping part 5.1 from above. This result axis 1
Upper and lower tightening parts 5.1 and 5.2 with 0 as the fulcrum
narrows and tightens the friction disk 2a fixed to the lower leg connection part 6. As a result, the upper and lower tightening parts 5.1 and 5.2 and the friction disk 2a are fixed, and the lower tightening part 5.2 is fixed to the lower leg, and the shaft attached to it is fixed. This means that position 2 is also fixed. After that, the thigh connection part is made of elastic body 4a in response to the increase in the load from the upper body.
The thigh connecting part 3 rotates around the axis 1 by the amount that is compressed, and when the load decreases, the amount of compression of the elastic body 4a decreases, so the thigh connecting part 3 returns to its original state. By such movement, the bending and stretching movement of the knee between A and E can be approximated.

In addition, when leaving the bed between I and M, the entire upper clamping part 5.1 and below, including the elastic body 4a, is suspended from the shaft 1, contrary to the case where the load is applied from the upper body, so the friction disc 2a The lower leg, which is connected to the friction disk, is free to swing without being tightened.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of changes in the posture of the right side of the body during one cycle of human walking, Fig. 2 is an explanatory diagram of the knee joint mechanism of a conventional prosthetic leg, Fig. 3 is a diagram showing an embodiment of the present invention, and Fig. 4 is a perspective view of an example. 1, 2 and 10...axis, 3...femoral connection part,
4... Spacer, 5... Tightening part, 6... Lower leg connection part, 7 and 8... Stopper, 2a... Friction disk, 4a... Elastic body, 5.1... Upper tightening part, 5. 2...Lower tightening parts.

Claims (1)

[Claims] 1. In order to completely prevent the knee from bending when the foot lands on the floor and to give elasticity to the knee, a friction disk 2a is fixed to the lower leg, and the friction disk is held between the upper and lower sides and is attached to an axis behind the knee. an upper and a lower tightening part 5.1, 5.2 which are connected together, a part 3 which is connected to the lower tightening part by a shaft in front of the knee and is connected and fixed to the thigh, and a part 3 which is connected and fixed to the thigh; A knee joint mechanism constituted by an elastic body 4a inserted between the tightening parts.