WO2021154184A1

WO2021154184A1 - Hydraulic actuator for controlling flexion and extension speed of the prosthetic knee joint

Info

Publication number: WO2021154184A1
Application number: PCT/TR2021/050074
Authority: WO
Inventors: Ilhan SAHIN
Original assignee: Proted Protez Ortez Ve Rehabilitasyon Ltd. Sti.
Priority date: 2020-01-27
Filing date: 2021-01-27
Publication date: 2021-08-05

Abstract

The invention enables to control with manual adjustment elements (6) the flexion and extension speeds that are movements of the prosthetic knee joint using a speed and direction control mechanism (10). Thereby a controllable artificial knee joint can be created.

Description

HYDRAULIC ACTUATOR FOR CONTROLLING FLEXION AND EXTENSION

SPEED OF THE PROSTHETIC KNEE JOINT

DESCRIPTION

Technical Field

The invention enables to control the flexion and extension speeds that are movements of the prosthetic knee joint with a hydraulic trigger using a manual adjustment valve. Thereby a controllable artificial knee joint can be created.

Prior Art

In the prior art, flexion and extension movement speed in the known knee joints is adjusted by installing the spring trigger. Also, in some simpler knee and/or foot joints, flexion and extension speeds are controlled by the same adjustment mechanism. Since these knee joints have a single adjustment mechanism, they cannot fully mimic the user's gait.

Hydraulic systems used in industrial products are generally controlled by a pump to provide system control. Hydraulic systems known as actuator type, function together with a joint linkage and a linear/rotary electric motor. In such systems, compression and extension speeds of the piston stroke can be controlled by a regulator or servo valve. However, although these systems function effectively, they are not suitable to be used in prosthesis/orthosis systems due to their large physical parameters.

In addition, hydraulic systems developed to be used in the field of prosthesis-orthosis are more complex in structure and their production costs are quite high. Patent application numbered US2013123941 mentions a knee joint suitable to be used in prostheses. The embodiment subject to the application relates to a prosthetic knee joint, comprising an upper part with upper connection means and a lower part rotatably mounted to the upper part, having a lower linkage.

Patent application numbered US2008269912 mentions an artificial leg. The embodiment subject to the application is an artificial leg with an artificial knee having a joint body that can rotate around the axis of the joint to carry a femoral stump.

It is thought that the embodiment of the application numbered US2008269912 is formed by connecting a hydraulic member to a mechanical rotation member by means of a shaft. However, providing the rotational movement of the knee with a mechanical rotating member makes the system more complex and larger. On the other hand, operating the hydraulic system together with a mechanical rotating member may make the system more unstable during operation.

Patent application numbered US2005234562 describes a prosthetic leg with a knee bending function.

With the embodiment of the application numbered US2005234562, it is aimed, to provide a prosthetic limb with a flexible knee brake function and, to mechanically determine the foot on which the user's load is applied.

For this purpose, the hydraulic member is equipped with a hydraulic brake circuit. However, the prosthesis set consisting of the hydraulic member, hydraulic brake circuit and the members connecting them creates a disadvantage because of their complex and large dimensions. The Problems to be Solved by the Invention

The aim of the invention is to provide a controllable artificial knee joint that enables to control, with a manual adjustment valve, the flexion and extension speeds that are movements of the prosthetic knee joints using a hydraulic trigger.

The hydraulic trigger (actuator) of the present invention does not require a motor or pump, as it operates only by a spring trigger. Thus, the hydraulic flow can be controlled in a narrow area.

Although the hydraulic system of the invention is expensive compared to other prosthesis-orthosis systems, its production costs are lower compared to the hydraulic systems that are known and are effectively used in the prior art. These effective systems utilize many flow direction controllers in their structures; the system set forth by the invention can be operated with only 2 check valves therein.

Due to the manufacturing technology developed over time, pneumatic and hydraulic systems have been adapted to the prosthesis and orthosis fields. In this type of new generation knee joints, flexion and extension speeds can be controlled at individual speeds. In addition, since the fluids within hydraulic systems are incompressible substances, flexion and extension speed adjustments can be carried out in a more stable and effective manner. For these reasons, the solution of the technical problem is indicated by the fact that the flexion and extension speeds can be controlled separately.

The solution of another technical problem is that the mechanical structure of the check valve (2 pieces) and the adjustment valve (2 pieces) in the hydraulic system can be controlled in a single cross-sectional area. Thus, it is another important feature of the invention that the specified mechanical structure is designed to function effectively in a narrow space due to the small size of the prosthetic knee joints.

Description of Figures

Figure 1. Exploded view of the hydraulic control mechanism, Figure 2. Side view of the disassembled cylinder body,

Figure 3. Perspective view of the hydraulic movement mechanism,

Figure 4. Top cross-sectional view of the hydraulic control mechanism,

Figure 5. Side sectional view of the extended state of the piston,

Figure 6. Side sectional view of the compressed state of the piston,

Description of References in the Figures

I.Flow control member 2.Sealing member

3.Controller triggering member

4.Direction control member

5.Cylinder body

6.Adjustment element

7.Mounting plate

8.Mounting member

9.Flow hole

10. Speed and direction control mechanism 10.1.Wall

II. Adjustment hole

12. Connection channel Description of the Invention

The invention aims to control with a manual adjustment element (s) (6), the flexion and extension speeds that are the movements of the prosthetic knee joint using a hydraulic speed and direction control mechanism (10).

For this purpose, the piston operated in the cylinder body (5) in order to operate the knee joint of a prosthetic leg is equipped with a speed and direction control mechanism (10) at one end. The speed and direction control mechanism (10) can allow the control of the system by means of the adjustment element (6) in its structure.

According to the figures, the speed and direction control mechanism (10) is positioned at the lower part of the cylinder body (5), that is, at the end where the prosthesis is not attached to the stump.

According to Figure 1, the speed and direction control mechanism (10) includes two flow holes (9) that are opposed to each other and are formed on the side walls (10.1) of the speed and direction control mechanism (10), at least two adjustment holes (11) formed in relation to said flow hole (9) on the adjacent wall (10.1) of the speed/direction control mechanism (10).

In Figure 4, the flow holes (9) are shown in more detail. More specifically, the flow holes (9) formed correspondingly on the side walls (10.1) and the adjustment holes (11) formed on the adjacent wall (10.1), are formed perpendicular to each other. Adjustment holes (11) contain adjustment elements (6). The adjustment elements (6) aim to suppress the flow through the flow holes (9).

Flow control elements (1) operate within the flow holes (9) which are formed correspondingly.

According to Figure 1, the flow control member (1) operates in relation with at least one sealing member (2), the controller triggering member (3), and the direction control member (4), and it functions in each flow hole (9) as shown in Figure 2.

According to the preferred embodiment of the invention, the flow control member (1) is in the form of a check valve.

Again, according to Figure 1, one of the flow control members (1) that is in the form of a check valve that is positioned correspondingly is short and the other is long.

According to the preferred embodiment of the invention, the sealing member (2) is in the form of an o-ring and it is positioned at the continuation of the flow control member (1), closing the flow hole (9) when the flow control member (1) is closed.

According to the preferred embodiment of the invention, the controller triggering member (3) is in the form of a spring. The controller triggering member (3) that is formed as a spring allows the direction control member (4) to be turned on and off.

According to the preferred embodiment of the invention, the direction control member (4) is in the form of a plug. The direction control member (4) aims to be able to open and close the connection channel (12). Within the preferred embodiment of the invention, the adjustment element (6) has a valve structure. The adjustment element (6) is located inside the adjustment hole (11) together with a sealing member (2). The sealing member (2) that is positioned inside the adjustment hole (11) can also be an o-ring.

According to Figure 1, the wall (10.1), which is equipped with the adjustment element (6), has a mounting plate (7) formed on the adjustment element (6). The assembly of the mounting plate (7) is provided by means a mounting member (8).

While the piston is carrying out the compression process, one of the flow control members (1) operates through the flow hole (9) therein. For example, in Figure 2, the flow control member (1) in the structure of short check valve operating on the left wall (10.1) is the one that functions during compression.

With the flow passing through the piston, it activates the direction control member (4) and the flow out of the piston is activated with the hole associated with flow hole (9) that is located in the cylinder body (5).

As the piston extends, the fluid passes through another flow hole (9) shown in Figure 4 that is associated with the cylinder body (5) and it actuates the other flow control member (1). For example, in Figure 1, the flow control member (1) in the structure of long check valve operating on the right wall (10.1) is the one that functions during extension.

The flow direction is controlled in this way with the two flow control members (1). With the simple and compact design of the mechanism, there is no need to use additional check valves.

After the flow directions are determined by the flow control mechanisms (1), the speed of the fluid is controlled by the adjustment element (6). When the piston moves in the compression direction, the first flow control mechanism (1) operates and the flow moves from the first flow control mechanism (1) to the hole formed in the cylinder body. These hole structures are seen in Figure 4.

According to the preferred embodiment of the invention, each adjustment element (6) formed on the speed and direction control mechanism (10) aims to function together with the flow hole (9) of each flow control member (1).

When the user interacts with the relevant adjustment element (6), the flow holes located in the speed and direction control mechanism (10) can be throttled and opened by the adjustment element (6). For this purpose, each adjustment element (6) has a structure that can move back and forth within the adjustment hole (11).

According to the preferred embodiment of the invention, the adjustment element (6) includes a thread that allows the user to tighten or loosen it with a screwdriver or similar equipment from the outside. Thus, the user can regulate the flow in the flow channel by means of the adjustment element (6) with a screwdriver.

As this situation turns into action, the knee joint gains the ability to perform the flexion movement. If the user wishes, the adjustment element (6) that controls the speed of the fluid passing through the flow control members (1), can completely cut the flow. Thus, the flow is not only regulated but also the flow can be cut off.

As the piston extends, it passes through the flow hole (9) in front of the flow control members (1) shown in Figure 4. The fluid passing in front of one of the flow control members (1) (for example the long one) pushes the direction control member (4) and movement into the piston begins. In this case, the fluid passes through the flow hole (9) in front of the adjustment element (6) that regulates the other (for example, the long one) flow control member (1), but the flow is cut off by the direction control member (4) located on the other flow control member (1) (the short one). Therefore, only the long flow control member (1) and the adjustment element (6) located next to the long flow control member (1) are active. This condition of the knee joint is defined as the flexion movement.

Figure 5 shows the extended state of the piston and the effect of this piston movement on the knee joint. Figure 6 shows the compressed state of the piston and the effect of this piston movement on the knee joint.

The system provides all these adjustments and the piston compression movement, by a material it includes. Due to its closed cell structure, this material traps the air in the piston. While the compression movement and adjustment element (6) adjustments are made, the excess volume entering the system is balanced by this accumulator.

With the information in the above paragraphs, it has been described in detail how the hydraulic control mechanism functions. With the embodiment in Figure 3, the hydraulic system was mounted on a polycentric body and in this way, knee flexion and extension movements can be performed. However, by connecting the hydraulic system to a monocentric body or a joint, its speed and position can be controlled. There is no restriction in the working area of the hydraulic system.

According to a different embodiment of the invention, two flow holes (9) formed in the side walls (10.1) of the speed and direction control mechanism (10) correspondingly, are controlled by a single flow control member (1). Thus, the system can have smaller physical parameters.

Claims

1.A speed and direction control mechanism (10) comprising a piston in the cylinder body (5) in order to operate the knee joint of a prosthetic leg, that aims to control by means manual adjustment elements (6), the flexion and extension speeds that are the knee movements of the prosthetic knee joints, characterized in that it comprises;

• two flow holes (9) correspondingly formed in the side walls (10.1) of the speed and direction control mechanism (10), that are associated with the hole belonging to the cylinder body (5),

• at least two adjustment holes (11) formed on the adjacent wall (10.1) of the speed and direction control mechanism (10) such as to be in relation with the flow hole (9),

• at least one flow control member (1) that regulates the flow between the flow holes (9) and the hole in the cylinder body (5) by functioning within the said adjustment holes,

• adjustment elements (6) that can be positioned in said adjustment holes (11) that suppress the flow formed in the flow holes (9).

2.A speed and direction control mechanism (10) according to claim 1, characterized in that the cylinder body (5) is positioned at the end where the prosthesis is not attached to the stump.

3.A speed and direction control mechanism (10) according to claim 1, characterized in that it includes the flow holes (9) formed correspondingly on the side walls (10.1) and the adjustment holes (11) formed perpendicular to them on the adjacent wall (10.1).

4.A speed and direction control mechanism (10) according to claim 1, characterized in that it includes 2 flow control members (1) also functioning in each flow hole (9).

5.A speed and direction control mechanism (10) according to any one of the preceding claims, characterized in that it includes at least one sealing member (2), controller triggering member (3), and flow control member (1) that are operated separately in each flow hole (9) by functioning in relation to the direction control member (4).

6.A speed and direction control mechanism (10) according to claim 5, characterized in that it includes flow control members (1) in the form of a check valve.

7.A speed and direction control mechanism (10) according to claim 6, characterized in that it includes flow control members (1) oppositely positioned in the form of check valves, one of which is longer than the other.

8.A speed and direction control mechanism (10) according to claim 5, characterized in that it includes a sealing member (2) in the form of an o-ring.

9.A speed and direction control mechanism (10) according to claim 5, characterized in that it includes the controller triggering member (3) in the form of a spring.

10. A speed and direction control mechanism (10) according to claim 5, characterized in that it includes the direction control member (4) in the form of a plug.

11. A speed and direction control mechanism (10) according to any one of the preceding claims, characterized in that it includes the wall (10.1) that is equipped with the adjustment element (6) and a mounting plate (7) that is formed on the adjustment element (6).

12. A speed and direction control mechanism (10) according to claim 11, characterized in that it includes the mounting plate (7) that is mounted by a mounting member (8).

13. A speed and direction control mechanism (10) according to any one of the preceding claims, characterized in that it includes a separate adjustment element (6) that functions together with the flow hole (9) of each flow control member (1).

14. A speed and direction control mechanism (10) according to any one of the preceding claims, characterized in that it includes the adjustment element (6) having a structure that can move back and forth within the adjustment hole (11) when the user interacts with the relevant adjustment element (6).

15. A speed and direction control mechanism (10) according to claim 14, characterized in that it includes the adjustment element (6) equipped with a thread that allows the user to tighten or loosen it from the outside, with a screwdriver or with the use of similar equipment.