JPH06197917A - Cylinder for artificial leg - Google Patents

Abstract

PURPOSE:To provide a cylinder for an artificial leg having a cushion throttling mechanism capable of automatically adjusting a terminal impact corresponding to the shaking speed of a lower limb frame. CONSTITUTION:The cylinder is provided between the femur frame and lower limb frame both of which are connected in a freely shakable manner. In this cylinder, when the large diameter part 24 provided to a piston 12 is fitted in the inner hole 24 provided to a rod cover 14, the inner hole 24 and a head side chamber 16 are connected by a passage 18b through the check valve 18a provided in the large diameter part 24 and, further, a rod side chamber 17 and the inner hole 24 are connected by the passage 50 provided in the rod cover 14 and the opening area of the passage 50 is adjusted by the throttle 52 provided to the passage 50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prosthesis cylinder used as a prosthesis for a person without a knee whose thigh has been cut.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a prosthesis for a person who has been cut and has no knees has a lower leg frame 2 swingably attached to a thigh frame 1 by means of a shaft 3 as well as the thigh frame 1 described above. There is a structure in which a cylinder 5 is rotatably provided between the lower leg frame 2 by a shaft 7 and a shaft 6.

As shown in detail in FIG. 5, the cylinder 5 constitutes a main body 8 by fixing a head cover 11 and a rod cover 14 to both ends of a sleeve 15. The piston 12 fixed to the large diameter portion 22 of the rod 13 is slidably fitted into the sleeve 15 of the main body 8, and the piston 12 divides the sleeve 15 into a head side chamber 16 and a rod side chamber 17. The rod 13 is provided with a mounting portion 6a having a hole through which the shaft 6 of FIG. 4 penetrates at the tip thereof that penetrates the rod cover 14 and projects to the outside of the main body 8. The head cover 11 has a mounting portion 7a at the tip thereof, through which the shaft 7 of FIG. 4 penetrates.

The large-diameter portion 22 of the rod 13 fixed to the piston 12 is configured to be fitted into the inner hole 24 provided in the rod cover 14 when the piston 12 moves downward and nears the end thereof. 21e and this passage 21e
A passage 18b having a check valve 18a therein is provided parallel to the above. The passage 21e has a valve seat 21f with which the tip of a needle valve 20a provided inside the rod 13 abuts, and the passage 21e and the needle valve 20a constitute a throttle valve 21a.

The needle valve 20a is slidably provided inside the rod 13, and its tip is provided with the passage 21.
It can come into contact with the valve seat 21f of e, and its lower end is
It is in contact with a motor 30 controlled by a computer. The needle valve 20a connects the motor 30 and the needle valve 20a by constantly contacting the motor 30 with a spring 32 provided between the flange 31 and the inner hole of the rod 13. Therefore, the throttle valve 21a is connected to the motor 3
The configuration is such that the opening degree is adjusted by rotation of 0.

A passage 21b is provided in a connecting portion of the rod 13 with the large diameter portion 22, and a valve seat 21f of the throttle valve 21a and a passage 18b of the check valve 18a are opened in the passage 21b. Since this check valve 18a has the direction from the rod side chamber 17 to the head side chamber 16 as the forward direction, the piston 12 begins to move downward from the position of FIG. 5 and the tip of the large diameter portion 22 enters the inner hole 24. Until it is inserted, the rod side chamber 17
Is freely circulated to the head side chamber 16. That is, the resistance when the cylinder 5 is extended is reduced.

When the cylinder 5 extends, the large diameter portion 22
A seal 25 having a V-shaped cross section is provided at the opening end of the inner hole 24 to the rod-side chamber 17, and the opening of the V-shaped cross-section is provided toward the rod-side chamber 17. is there. Further, the throttle 27 is constituted by a needle valve 27a provided on the same axis as the axis of the passage 27b opening at the end surface of the rod cover 14 in the direction of the rod side chamber 17, and the throttle 2
The lower end of 7 is connected to the lower end of the inner hole 24 by a passage 27c.

When the large-diameter portion 22 is fitted into the seal 25 provided at the opening end of the inner hole 24, the throttle 27 has the rod-side chamber 1
7, the head side chamber 16 is connected to the inner hole 24 by a passage constituted by the check valve 18a, the passage 18b and the passage 21b. Rod side chamber 17
Since the seal 25 receives the pressure of the rod-side chamber 17 in the V-shaped open portion of its cross section, the lip of the seal 25 follows the surface of the large diameter portion 22. Therefore, the air in the rod-side chamber 17 flows out to the head-side chamber 16 via only the throttle 27, so that the cylinder 5 has a cushioning action.

In the throttle valve 21a of the cylinder 5 described above, when the piston 12 moves upward from the lower end, the check valve 18a closes the air in the head side chamber 16, so that the passage 21
From e through the throttle valve 21a, it flows out from the passage 21b to the inner hole 24. Since the change in the volume of the head side chamber 16 due to the movement of the piston 12 is larger than the change in the volume of the inner hole 24, the amount of air flowing from the head side chamber 16 into the inner hole 24 is equal to the inner hole 24.
Larger than the volume of. This portion pushes up the lip of the seal 25 and flows into the rod side chamber 17. Therefore, the operating speed of the piston 12 is determined by the opening degree of the throttle valve 21a. Therefore, by controlling the opening of the throttle valve 21a according to the walking speed by the motor 30, the artificial leg is swung according to the walking speed.

The operation when the above-described cylinder 5 having the above structure is applied to a prosthesis will be described. FIG. 6 shows a person moving from a standing state until the heel touches the ground, and the person is represented by a line. In FIG. 6, a1
Is head, a2 is back, a3 is waist, a4 is knee, a5 is heel, a
6 represents each toe. 1, 2 are the thigh frames described above,
The lower leg frame.

FIG. 6 shows a state in which the heel a5 is grounded and then is again grounded. A position b1 shows a time when the heel a5 is grounded, and a position c6 shows a position immediately before the heel a5 is grounded again. In the walking state of a person, the cycle of one leg is decomposed and represented from the position b1 to the position c6. In FIG. 6, the period from the state where the heel a5 at the position b1 is in contact with the ground until the toe a6 at the position b7 is separated from the ground surface is called a stance phase D1, and the period until the toe a6 is separated from the ground and the heel a5 is grounded. This is called swing phase D2. In the walking of a person, when one of the two legs is in the swing phase D2, the other is in the stance phase D1,
Walking is performed by alternately repeating the standing phase D1 and the swing phase D2.

The stance phase D1 is a position b1 where the heel a5 is in contact with the ground.
It starts from and ends at a position b7 where the toe a6 is separated from the ground. At this position b1, the thigh frame 1 and the lower leg frame 2 are substantially in a straight line, and the back a2 and the head a1 are located slightly behind the heel a5. From the position b1 to the position b2, the position b3, and the position b4 where the person stands upright, the human body is centered around the heel a5 and the thigh frame 1
And the lower leg frame 2 rotate in a straight line, and when the toe a6 touches the ground at the position b4, the head a1 to the heel a5 become substantially straight at almost the same time. The movement of the person from the position b4 to the position b5, the position b6, and the position b7 in an upright state is that the head a1 to the heel a5 is almost in a straight line and inclines toward the front, and from the position b6 to the waist a3. The upper body of the person is slightly raised, and the thigh frame 1 and the lower thigh frame 2 continue to rotate around the toe a6. In this way, from the position b5 to the position b7, the thigh frame 1 and the crus frame 2 are in a substantially straight line, the position b7 is reached around the toe a6, the standing phase D1 is completed, and the free phase D2 is started.

The free leg phase D2 starts at a position c1 where the toe a6 is separated from the ground and ends at a position c6 where the heel a5 is in contact with the ground. From this position c1, the lower leg frame 2 starts to rotate backward about the knee a4 with respect to the thigh frame 1,
At the position c3, the thigh frame 1 and the crus frame 2 are bent at maximum. Then, from this position c3, the swing phase D2
Until reaching the position c6, the lower leg frame 2 rotates forward with respect to the thigh frame 1, the thigh frame 1 and the lower leg frame 2 are in a substantially straight line state again, and the swing phase D2
Ends, and the phase shifts to the stance phase D1.

Next, a description will be given of a case where the artificial leg using the cylinder 5 shown in FIG. 5 is operated to walk the person as shown in FIG. In FIG. 6, from the position b1 to the position b6 of the stance phase D1, the thigh frame 1 and the lower thigh frame 2 extend in a substantially straight line, so that the rod 13 of the cylinder 5 is in an extended state. From this state, as the walking progresses, the lower leg frame 2 starts to be swung backward from the thigh frame 1 from the position b7, and reaches the maximum position when reaching the position c3. At the position b7, since the rod 13 is extended, the large diameter portion 22 reaches the lower end of the inner hole 24, and the position b
The rod 13 starts to shrink from 7 toward the position c3.

At the time of this reduction, the head side chamber 16 of the cylinder 5 is
Is compressed, and a part of the compressed air is discharged from the passage 21b to the inner hole 24 through the throttle valve 21a. Therefore, the swing-up speed of the lower leg frame 2 has a value corresponding to the moving speed of the piston 12, that is, the opening degree of the throttle valve 21a. During this operation, the change in the volume of the head side chamber 16 is larger than the change in the volume of the inner hole 24.
A part of the air flowing in via the seal gas flows into the rod side chamber 17 via the seal 25.

When the human body reaches the position c3, the rod 13 of the cylinder 5 is contracted as shown in FIG. 5, the lower leg frame 2 is swung out from this position c3, and the thigh frame 1 and the lower leg frame 2 are substantially aligned at the position c6. Next, the position b1 is reached again. When the lower leg frame 2 starts to swing down from the position c3, the piston 12 receives a pressing force due to the air pressure remaining in the inner hole 24 of the head side chamber 16, so that the lower leg frame 2 is swung out. The air pressure in the head-side chamber 16 decreases due to this swing-out, and the air pressure in the rod-side chamber 17 increases,
The air in the rod-side chamber 17 is supplied to the check valve 1 through the passage 21b.
Since it flows into the head side chamber 16 via 8a, the lower leg frame 2 is swung out without resistance.

When the lower leg frame 2 is swung out to a position near the position c5, the large diameter portion 22 connected to the piston 12 is fitted into the seal 25, so that the passage 21b is opened only in the inner hole 24 and the head side chamber 16 is formed. The rod-side chamber 17 is connected only via the diaphragm 27. Therefore, the air in the rod side chamber 17 passes through the throttle 27a, the inner hole 24, the passage 21b, and the check valve 18a.
Through the head side chamber 16. Therefore, the air pressure in the rod-side chamber 17 rises according to the opening area of the throttle 27, and the moving speed of the piston 12 decreases. For this reason, the swing-down speed of the lower leg frame 2 also decreases, and the position c
6, the impact at the time of contact between the tip 2b of the lower thigh frame 2 and the lower end of the thigh frame 1 when the thigh frame 1 and the lower thigh frame 2 are substantially aligned with each other is mitigated.

[0018]

However, as described in the prior art, when the large-diameter portion 22 is fitted into the seal 25 provided at the opening end of the inner hole 24, the air in the rod side chamber 17 is limited to the throttle 27. Flows into the head side chamber 16 through the cylinder 5 and creates a cushioning effect on the cylinder 5.
Since the opening area of is constant, the cushioning force does not change depending on the swing-out speed of the lower leg frame 2, and the walking speed suddenly increases even if the cushioning force is sufficient at a normal walking speed. Lower leg frame 2
If the cushioning force is not sufficient when the rocking speed of the thigh frame 1 becomes fast, when the tip of the thigh frame 2 and the lower end of the thigh frame 1 come into contact with each other when the thigh frame 1 and the thigh frame 2 are substantially aligned with each other. In some cases, the impact, so-called terminal impact, becomes large. If this terminal impact is too strong, there is a problem that the prosthetic leg wearer feels uncomfortable and interferes with natural walking.

[0019]

In order to solve the above problems, the present invention is provided between a thigh frame and a crus frame of a prosthesis so that the thigh frame and the crus frame are swingably connected to each other. The thigh frame and the lower leg frame are provided with a throttle valve mechanism that stretches the thigh frame and the lower leg frame by providing a proper resistance when the thigh frame and the lower leg frame are flexed during the swing phase and a repulsive force when the leg is advanced. In a cylinder configured to give resistance again immediately before extension and to prevent impact at the time of extension, in the cylinder, a rod-fixed piston is slid into a sleeve of a main body in which a rod cover and a head cover are fixed to both ends of the sleeve. The rod is movably fitted in, the rod penetrates the rod cover and slidably projects to the outside, and the piston is inserted into the sleeve. Is divided into a de-side chamber and the rod-side chamber,
The rod is provided with a large-diameter portion connected to the piston, and the large-diameter portion is fitted into an inner hole provided in the rod cover near the end of the piston in the rod-side chamber direction,
A passage is formed in the rod to connect the inner hole to the head-side chamber when the large-diameter portion is fitted into the inner hole, and a forward direction from the rod-side chamber to the head-side chamber is defined in this passage. A check valve and an externally adjustable throttle valve are provided in parallel, and the rod cover has a throttle degree between the rod side chamber and the inner hole, the throttle degree of which is reduced in inverse proportion to the swinging speed of the lower leg frame. Is provided.

[0020]

According to the above means, the degree of throttling of the throttling mechanism decreases in inverse proportion to the swing-out swing speed of the lower leg frame. Therefore, when the large-diameter portion is fitted into the inner hole, the air in the rod-side chamber controls this throttling. Since it passes through, it acts as a cushion that increases the air pressure in the rod-side chamber by regulating the flow rate and slows down the moving speed of the piston.
When the swing-out swing speed of the lower leg frame becomes faster, the degree of throttling becomes smaller and the swing-out speed of the lower leg frame becomes faster, which restricts the flow of air from the rod side chamber to the head side chamber. The faster it becomes, the greater the cushioning effect becomes. On the contrary, when the swinging swing speed becomes slow, the diaphragm becomes large and the cushioning effect becomes small. Therefore, it functions to adjust the cushioning action according to the swing speed of the lower leg frame, that is, the walking speed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cushion diaphragm mechanism for a prosthetic leg cylinder according to the present invention will be described below with reference to the drawings. In the embodiment, the same parts as those of the above-mentioned conventional cylinder 5 are designated by the same reference numerals, and the description thereof will be omitted.
Only the features that characterize the present invention will be described.

In the first embodiment according to the present invention, as shown in FIGS. 1 and 2, a passage 50a is opened at the lower end of the inner hole 24 provided in the rod cover 14 of the cylinder 5a, and the passage 50a is the above-mentioned. A passage 50b that connects the rod-side chamber 17 and the inner hole 24 is formed by opening a passage 50b that is provided in parallel with the inner hole 24 and opens to the rod-side chamber 17. A donut type valve seat 51 is provided on the inner peripheral wall in the middle of the passage 50b, and a shaft 52a forming a throttle 52 is slidable in the axial direction of the through hole 51a near the center of the valve seat 51. The flange 52b that is fitted and fixed to the shaft 52a is elastically biased by the coil spring 53 housed in the passage 50b and is in contact with the valve seat 51. Further, as often shown in FIG. 3, an inclined groove 52c is formed so as to deepen in the direction of the flange 52b from the shaft 52a to the flange 52b, and the shaft 52a slides in the through hole 51a of the valve seat 51. When moved dynamically, the boundary surface of the rod side chamber 17 of the valve seat 51 and the shaft 52
The opening area formed by the inclined groove 52c provided in a changes. This opening area becomes smaller as the brim 52b moves away from the valve seat 51. The valve seat 5
1 receives the coil spring 53 through the collar 52b of the diaphragm 52.
The elastic force of the can be adjusted by the screw body 54 that seals the passage 50b.

Cylinder 5a having such a diaphragm mechanism
When the large diameter portion 22 connected to the piston 12 is fitted into the inner hole 24 provided in the rod cover 14, the air in the rod side chamber 17 flows into the passage 50b opened in the rod side chamber 17, and the valve seat is opened. A passage 50b passing through an opening of the inclined groove 52c of the diaphragm 52 and the diaphragm 52 and accommodating the coil spring 53 therein.
Through the passage 50a to the inner hole 24, and further to the passage 2
1b flows into the head side chamber 16 through the check valve 18a. Therefore, when the flow of air is restricted by the throttle 52, the air in the rod side chamber 17 is compressed, so that the pressure increases, and a cushioning action that damps the movement of the piston 12 occurs. In this way, in the cushion region where the large diameter portion 22 fits into the inner hole 24, the piston 1
Since the force that damps the movement of 2 acts according to the opening area of the diaphragm 52, the diaphragm 52 causes the coil spring 5 to move.
When the brim 52b moves away from the valve seat 51 against the elastic force of 3, the opening area formed by the boundary surface of the valve seat 51 on the rod side chamber 17 side and the inclined groove 52c of the shaft 52a becomes small. Since the air pressure in the rod side chamber 17 increases, the force that damps the movement of the piston 12 increases.

Cylinder 5a having such a throttle mechanism
The operation in the case of attaching the to the artificial leg will be described with reference to FIGS. 1 and 6. In FIG. 6, when the lower leg frame 2 reaches the position c3 in the swing phase D2, the head side chamber 16
The flow of air from the rod side chamber 17 to the rod side chamber 17 is performed by the check valve 1 of FIG.
The air in the head side chamber 16 is in a compressed state because it is restricted by the 8a and the throttle valve 21a. When the lower leg frame 2 starts to swing forward due to the compressed air pressure of the head side chamber 16, the diaphragm 52 of the diaphragm mechanism receives a centrifugal force and resists the elastic force of the coil spring 53, so that the collar 52b is located inside the passage 50b. It moves away from the valve seat 51.
Therefore, this amount of movement is determined by the balance between the centrifugal force received by the diaphragm 52 and the elastic force of the coil spring 53, and the magnitude of this centrifugal force depends on the shaking speed of the lower leg frame 2. The higher the shaking speed of the lower leg frame 2, the larger the movement amount of the diaphragm 52, and conversely, the smaller the shaking speed of the lower leg frame 2, the smaller the movement amount of the diaphragm 52. The shaft 52a and the collar 52 that constitute the diaphragm 52
Since the inclined groove 52c formed over b is deeper in the direction of the collar 52b, the larger the moving amount of the shaft 52a, the smaller the opening area formed by the valve seat 51 and the inclined groove 52c formed on the shaft 52a. Get smaller.

Then, when the lower leg frame 2 reaches the vicinity of the position c5, the large diameter portion 22 connected to the piston 12 becomes the inner hole 24.
, The inner hole 24 is sealed by the seal 25 that receives pressure from the rod side chamber 17, so that the head side chamber 16
The rod-side chamber 17 is provided with the inner holes 24
To the passageway 50. At this time, the diaphragm 52 is moving against the elastic force of the coil spring 53 according to the moving speed of the lower leg frame 2, and the diaphragm 52 has an inclined groove 52c formed from the shaft 52a to the flange 52b. Since it is deeper in the direction of the brim 52b from the tip of, the opening area of the diaphragm 52 corresponds to the moving speed of the lower leg frame 2. That is, if the moving speed of the lower leg frame 2 is high, the opening area of the throttle 52 is reduced to rapidly increase the air pressure of the rod side chamber 17 necessary for decelerating the piston 12, and conversely, the moving speed of the lower leg frame 2 is increased. If it is late, the opening area of the throttle 52 is increased so that the air pressure of the rod side chamber 17 necessary for deceleration is gradually increased.

In this way, when the lower leg frame 2 is decelerated and reaches the position c6, the terminal impact at which the lower end of the thigh frame 1 and the upper end of the lower leg frame 2 collide is automatically adjusted to an appropriate size. Has become.

[0027]

As described above, according to the present invention, when the lower leg frame is swung, the lower leg frame is swung out in the swing leg phase, and the large diameter portion connected to the piston in the cylinder is aforesaid. When fitted into the inner hole, the air from the rod side chamber passes through the throttle mechanism provided in the cylinder head and flows into the head side chamber, but this throttle mechanism reduces the aperture area of the throttle as the shaking speed of the lower leg frame increases. Automatically adjusts so that when the thigh frame and lower leg frame are extended, the cushioning force is applied to the piston according to the swinging speed of the lower leg frame, so that an appropriate terminal impact can be obtained, which causes discomfort to the prosthetic leg wearer. Natural walking can be realized without giving.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an embodiment of a cylinder incorporating a cushion diaphragm mechanism according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a perspective view showing an embodiment of a cushion diaphragm mechanism according to the present invention.

FIG. 4 is an overall explanatory view of a prosthesis in which a thigh frame and a lower leg frame are connected.

FIG. 5 is a partial cross-sectional view showing a conventional cylinder.

FIG. 6 is an exploded view of the motion of the artificial leg during walking.

[Explanation of symbols]

 1 Thigh frame 2 Lower leg frame 5a Cylinder 8 Main body 11 Head cover 12 Piston 13 Rod 14 Rod cover 15 Sleeve 16 Head side chamber 17 Rod side chamber 18a Check valve 21a Throttle valve 21e Passage 22 Large diameter part 24 Inner hole 52 Throttle

Claims (1)

[Claims] 1. A thigh frame and a crus frame of a prosthesis are swingably connected to each other and are provided between the thigh frame and the crus frame, which are suitable for bending the thigh frame and the crus frame during a swing phase. A throttle valve mechanism that applies resistance and repulsive force during extension and expands the thigh frame and lower leg frame by this repulsive force, and a configuration that again gives resistance immediately before the thigh frame and lower leg frame extend to prevent shock during extension. In the cylinder described above, a piston having a rod fixed therein is slidably fitted into a sleeve of a main body in which a rod cover and a head cover are fixed to both ends of the sleeve, and the rod penetrates the rod cover to externally. And a piston divides the sleeve into a head-side chamber and a rod-side chamber, and the rod has the piston. A large-diameter portion continuously provided to the ton, and the large-diameter portion is configured to be fitted into an inner hole provided in the rod cover near the terminal end of the piston in the rod-side chamber direction. A passage that connects the inner hole to the head-side chamber when fitted into the inner hole is opened, and in this passage, a check valve having a forward direction from the rod-side chamber to the head-side chamber, and an externally adjustable throttle. Cylinders for artificial legs, wherein valves are provided in parallel, and the rod cover is provided with a throttle between the rod side chamber and the inner hole, the throttle having a degree of throttling that is inversely proportional to the swinging swing speed of the lower leg frame. .