# US 10,441,440 B2 · Prosthesis with a passive release device

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- Number: US 10,441,440 B2
- Document ID: US10441440B2
- Status: Granted
- Kind: B2
- Application number: 15/305,132
- Filed: 2015-04-29
- Published: 2017-02-16
- Granted: 2019-10-15
- Earliest claimed: 2014-04-30
- Assignees: Ottobock SE & Co. Kgaa
- Applicants: Otto Bock Healthcare GmbH
- Inventors: Martin Pusch; Sven Kaltenborn; Luder Mosler; Georg Gehrmann; Carsten Monicke
- Web page: https://patentgrep.com/patent/US10441440B2

## CPC

- A61F 2/66: Feet; Ankle joints
- A61F 2/68: Operating or control means
- A61F 2/74: fluid {, i.e. hydraulic or pneumatic}
- A61F 2/748: {Valve systems}
- A61F 2002/6818: {for braking}
- A61F 2002/6854: {for locking or unlocking a joint}
- A61F 2002/7645: {for measuring torque, e.g. hinge or turning moment, moment of force}
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)

## Abstract

A prosthesis with a lower limb attachment part, a foot part, a connection element with a joint function that connects the lower limb attachment part with the foot part, and a release device which can be brought into a locking position in which the foot part and the lower limb attachment part are connected to each other in a rotationally fixed manner at least relative to a dorsal extension movement, and into a release position in which the foot part can be rotated relative to the lower limb attachment part. The release device is designed to passively switch from the locking position into the release position when a variable which correlates to an ankle torque (M) in the connection element lies above a pre-set threshold.

## Claims

### Claim 1

A prosthesis, comprising:
a lower limb attachment part;
a foot part;
a connection element with a joint function that connects the lower limb attachment part with the foot part; and
a release device that can be brought into a locking position, in which the foot part and the lower limb attachment part are connected to each other in a rotationally fixed manner at least relative to a dorsal extension movement, and into a release position, in which the foot part can be rotated relative to the lower limb attachment part;
wherein the release device is configured to passively switch from the locking position into the release position when a variable which correlates to an ankle torque in the connection element is above a preset threshold and during a stance phase prior to initiation of a swing phase during a gait cycle.

### Claim 2 (depends on 1)

The prosthesis according to claim 1, wherein the release device is configured to passively switch from the locking position into the release position when the variable is the ankle torque and the ankle torque lies above a preset torque threshold.

### Claim 3 (depends on 2)

The prosthesis according to claim 2, wherein the release device is configured such that
when the ankle torque lies above the torque threshold, the foot part moves into a dorsally extended position, and
the foot part remains in the dorsally extended position during the swing phase.

### Claim 4 (depends on 1)

The prosthesis according to claim 1, wherein the release device comprises:
a first hydraulic cylinder comprising:
a piston rod;
a cylinder housing;
a first end connected to the foot part; and
a second end connected to the lower limb attachment part; and
a restraint device configured to:
prevent a movement of the piston rod that leads to the dorsal extension movement of the foot part when the restraint device is in a closing position, and
enable the movement of the piston rod when the restraint device is in an open position.

### Claim 5 (depends on 4)

The prosthesis according to claim 4, wherein the restraint device comprises a first check valve configured to:
prevent the movement of the piston rod that leads to the dorsal extension movement of the foot part when the first check valve is in a closing position;
enable the dorsal extension movement of the foot part when the first check valve is in an open position; and
move out of the closing position into the open position at an opening pressure.

### Claim 6 (depends on 5)

The prosthesis according to claim 5, wherein the first check valve includes an excess pressure valve, and the torque threshold is set based on the opening pressure of the first check valve at which the excess pressure valve moves the first check valve out of the closing position into the open position.

### Claim 7 (depends on 5)

The prosthesis according to claim 5, wherein the restraint device comprises a second check valve configured to:
prevent a plantar flexion movement of the foot part when the second check valve is in a closing position;
enable the plantar flexion movement of the foot part when the second check valve is in an open position;
move the second check valve out of the second check valve closing position into the second check valve open position at a plantar flexion opening pressure.

### Claim 8 (depends on 7)

The prosthesis according to claim 7, wherein the first hydraulic cylinder is:
designed to be double-acting;
connected to the restraint device in such a way that the dorsal extension movement of the foot part only effects a flow of hydraulic fluid through the first check valve and the plantar flexion movement of the foot part only effects a flow of the hydraulic fluid through the second check valve.

### Claim 9 (depends on 7)

The prosthesis according to claim 7, wherein the release device comprises a second hydraulic cylinder comprising:
a second piston rod and a second cylinder housing;
a first end of the second hydraulic cylinder connected to the foot part;
a second end of the second hydraulic cylinder connected to the lower limb attachment part;
wherein the second hydraulic cylinder is connected to the restraint device and the first hydraulic cylinder such that:
the dorsal extension movement of the foot part effects a flow of hydraulic fluid from the hydraulic cylinder, through the first check valve and into the second hydraulic cylinder, and
the plantar flexion movement of the foot part effects a flow of the hydraulic fluid from the second hydraulic cylinder, through the second check valve and into the first hydraulic cylinder.

### Claim 10 (depends on 4)

The prosthesis according to claim 4, wherein the restraint device comprises a mechanical restraint element.

### Claim 11 (depends on 10)

The prosthesis according to claim 10, wherein the release device has a restraint structure and a spring, the restraint structure interacting with the restraint element in such a way that a movement of the foot part beyond a neutral position is only possible against the resistance of the spring.

### Claim 12 (depends on 10)

The prosthesis according to claim 10, wherein the release device comprises:
a mechanical return element;
a coupling ring;
a brake;
wherein the mechanical return element, coupling ring, and brake are connected to each other in such a way that when the foot part carries out the dorsal extension movement, the return element engages with the coupling ring such that the brake brakes the dorsal extension movement, and that when the foot part carries out a plantar flexion movement, the brake does not brake the plantar flexion movement, or brakes less strongly than the brake applied during the dorsal extension movement.

### Claim 13 (depends on 1)

The prosthesis according to claim 1, wherein the release device comprises a damping device, the damping device providing damping of at least one of:
the dorsal extension movement of the connection element, and
a plantar flexion movement of the connection element.

### Claim 14 (depends on 1)

The prosthesis according to claim 1, wherein
the foot part can be brought into a neutral position relative to the lower limb attachment part when a person wearing the prosthesis is standing, and into a dorsal extension position, and
the prosthesis comprises a mechanical pre-loading device configured to pre-load the foot part in the dorsal extension position.

### Claim 15 (depends on 1)

The prosthesis according to claim 1, wherein the prosthesis is a prosthetic foot comprising the foot part and wherein the connection element forms an ankle joint.

### Claim 16 (depends on 1)

The prosthesis according to claim 1, wherein the release device includes an excess pressure valve, wherein the preset threshold is adjusted by changing an opening pressure of the excess pressure valve.

### Claim 17 (depends on 16)

The prosthesis according to claim 16, wherein the excess pressure valve includes a pre-tensioning spring, and changing the opening pressure includes adjusting a spring force of the pre-tensioning spring.

### Claim 18

A prosthesis, comprising:
a lower limb attachment part;
a foot part;
a connection element having a joint function and being connected to the lower limb attachment part and the foot part; and
a release device that is configured to passively switch between a locking position, in which the foot part and the lower limb attachment part are fixed relative to each other at least relative to a dorsal extension movement, and a release position, in which the foot part is rotatable relative to the lower limb attachment part when a variable is above a preset threshold and during a stance phase prior to initiation of a swing phase during a gait cycle, the variable correlating to an ankle torque in the connection element, and the preset threshold is adjustable.

### Claim 19 (depends on 18)

The prosthesis according to claim 18, wherein the release device is configured to passively switch from the locking position to the release position when the variable is the ankle torque and the ankle torque lies above a preset torque threshold.

### Claim 20 (depends on 19)

The prosthesis according to claim 19, wherein the release device is configured to allow movement of the foot part into a dorsally extended position when the ankle torque lies above the torque threshold, and the foot part remains in the dorsally extended position during a swing phase.