Hydraulic damping cylinder, in particular for a knee prosthesis

Patent metadata

Field	Value
Publication number	US-9757253-B2
Application number	US-201514970781-A
Country	US
Kind code	B2
Filing date	Dec 16, 2015
Priority date	Dec 16, 2014
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

A hydraulic damping cylinder for a prosthetic knee joint, including a housing, a cylinder chamber in the housing and filled with a hydraulic fluid, and a piston arranged in the cylinder chamber and movable by a piston rod. In the housing there are provided at least two separate receiving chambers, which are of different size and are connected to the cylinder chamber by fluid ducts, for hydraulic fluid displaced from the cylinder chamber during a piston movement. The receiving chambers are each separated, by a diaphragm, from a compression chamber filled with a compressible fluid that forms an energy store. Upstream of the larger receiving chamber, there is connected a throttle device which forms a flow resistance for the hydraulic fluid flowing into the receiving chamber so that the hydraulic fluid can be distributed to the two receiving chambers in a manner dependent on speed of the piston movement.

First claim

We claim:

1. A hydraulic damping cylinder for a prosthetic knee joint, comprising a housing, a cylinder chamber which is provided in the housing and which is filled with a hydraulic fluid, and a piston which is arranged in said cylinder chamber and which can be moved in the cylinder chamber by way of a piston rod which is introduced into the cylinder chamber, wherein, in the housing, there are provided at least two separate receiving chambers, which are of different size and are connected to the cylinder chamber by way of fluid ducts, for hydraulic fluid displaced from the cylinder chamber during a piston movement, which receiving chambers are in each case separated, by way of a diaphragm, from a compression chamber filled with a compressible fluid that forms an energy store, wherein, upstream of one of the receiving chambers, which is a relatively large receiving chamber, there is connected a throttle device which forms a flow resistance for the hydraulic fluid flowing into the relatively large receiving chamber, in such a way that the hydraulic fluid can be distributed to the two receiving chambers in a manner dependent on the speed of the piston movement.

2. The damping cylinder according to claim 1 , wherein the cylinder chamber is formed by an insert component arranged in the housing.

3. The damping cylinder according to claim 1 , wherein the flow cross section of the throttle device is adjustable.

4. The damping cylinder according to claim 3 , wherein the throttle device comprises an adjustable throttle element by means of which the cross section of a flow bore which leads to the relatively large receiving chamber can be varied.

5. The damping cylinder according to claim 1 , wherein the throttle device is provided in the region of a base of the cylinder chamber, wherein the relatively large receiving chamber is also provided in the region of the cylinder chamber base, so as to surround the latter at least in sections, whereas the other of the receiving chambers, which is a small receiving chamber is provided thereabove in the region of a cylinder cover element.

6. The damping cylinder according to claim 1 , wherein a reversibly closable fluid supply opening is provided via which compressible fluid can be filled into or drained from the compression chambers.

7. The damping cylinder according to claim 6 , wherein the two compression chambers are connected to one another by way of a check valve which opens in the presence of a positive pressure in the compression chamber assigned to the relatively large receiving chamber.

8. The damping cylinder according to claim 1 , wherein the respective diaphragm is a rubber or plastics diaphragm.

9. The damping cylinder according to claim 1 , wherein, upstream of the receiving chambers, there is connected a switching valve by means of which, in a manner dependent on the position of the piston or of the piston rod, the hydraulic fluid flow can be supplied to the relatively large receiving chamber bypassing the throttle device or via the throttle device.

10. The damping cylinder according to claim 1 , wherein the switching valve comprises a stanchion which stands on a cylinder base and which is engaged over by the piston and by the piston rod and which communicates, via a bore, with the cylinder chamber such that hydraulic fluid can be supplied through the stanchion into the relatively large receiving chamber until the bore is closed by the piston that is moved in the direction of the cylinder base or by the piston rod, whereafter the hydraulic fluid flows via the throttle device.

11. The damping cylinder according to claim 10 , wherein a throttle element engages into the stanchion, and a flow bore is formed in the stanchion.

12. The damping cylinder according to claim 1 , wherein, on the piston, there is provided a check valve which opens during a movement in the direction of the cylinder base and by means of which that part of the cylinder chamber which is situated below the piston can be connected to that part of the cylinder chamber which is situated above the piston.

13. The damping cylinder according to claim 12 , wherein the check valve comprises a sealing ring, which engages around the piston rod, and a bore which is provided on the piston and which is engaged over by the sealing ring.

14. The damping cylinder according to claim 1 , wherein a throttle valve is provided, by means of which that part of the cylinder chamber which is situated below the piston communicates with that part of the cylinder chamber which is situated above the piston, via which throttle valve, during a movement of the piston in the direction of a cylinder cover element, hydraulic fluid flows from the part situated above the piston into the part situated below until said throttle valve is closed when a defined piston position is reached.

15. The damping cylinder according to claim 14 , wherein the throttle valve comprises a groove, which runs along a stanchion, and a bore which is formed on the piston or on the piston rod, which bore, when the throttle valve is open, communicates with the groove and with the upper part of the cylinder chamber.

16. The damping cylinder according to claim 1 , wherein at least one adjustment throttle valve is provided, by means of which the flow cross section of a hydraulic fluid duct, which connects that part of the cylinder chamber which is situated above the piston to the relatively small receiving chamber, can be varied.

17. The damping cylinder according to claim 16 , wherein the adjustment throttle valve comprises a throttle screw which is guided movably in the housing by way of a thread and by means of which the cross section of the hydraulic fluid duct can be varied.

18. The damping cylinder according to claim 16 , wherein a second adjustment throttle valve is provided which is secured, in particular sealed, in a fixed position so as to define a minimum throughflow.

19. The damping cylinder according to claim 1 , wherein an additional receiving chamber is provided for hydraulic fluid which flows back out of the relatively large receiving chamber during a movement of the piston in the direction of a cylinder cover element.

20. The damping cylinder according to claim 19 , wherein the additional receiving chamber is provided in the interior of the piston rod which is connected via a check valve to the interior of a stanchion, which check valve, during said movement, opens owing to the hydraulic fluid pressure imparted by the hydraulic fluid flowing from the relatively large receiving chamber into the stanchion.

21. The damping cylinder according to claim 20 , wherein, on the stanchion, there is provided at least one aperture which is arranged in the region of or above the check valve and at which a groove, which is formed on the outer side of the stanchion and which extends in the direction of the cylinder base, opens out.

22. A prosthetic knee joint comprising a damping cylinder according to claim 1 .

Assignees

• Ossur Iceland Ehf

Inventors

• Dressler Janek
• Kamm Thomas
• Zobirei Sören
• Tschupp Gabriel

Classifications

• F16F9/5126

  Piston, or piston-like valve elements (F16F9/504 takes precedence) · CPC title

• F16F9/446

  Adjustment of valve bias or pre-stress (F16F9/443 takes precedence) · CPC title

• F16F9/062 Primary

  Bi-tubular units · CPC title

• A61F2002/5038

  Hinged joint, e.g. with transverse axle restricting the movement · CPC title

• F16F9/19

  with a single cylinder {and of single-tube type} · CPC title