Adjustment system for a hydraulic actuator
AssigneeClaverham Limited
InventorsPaul Brewer, Reg Raval, Andrew Walton
Life of this patent
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Abstract
The present disclosure relates to an adjustment system a method for compensating for temperature variations in a spool valve. The spool valve and adjustment system may be parts in a duplex hydraulic actuator. The adjustment device comprises a spring, a pivot point, and a shape memory alloy (SMA) device. The spring and SMA device are disposed on either side of the pivot point to hold the pivot point in a first position. The SMA device is configured to change size in response to a temperature change so as move the pivot point to a second location. This may eliminate force fight in the duplex hydraulic actuator by preventing asynchronous activation of the spool valves due to thermal expansion within the spool valves.
Claims12
An adjustment system for adjusting a position of an actuator shaft within a spool valve, the adjustment device comprising:
- a spring;
- a pivot point;
- and
- a shape memory alloy (SMA) device,
- wherein the spring and the SMA device are disposed on either side of the pivot point to bias the pivot point to a first location,
- wherein the SMA device is configured to change size in response to a temperature change so as bias the pivot point to a second location.
A method of preventing force fight in a duplex hydraulic system, wherein the duplex hydraulic system comprises
- a summing lever system comprising a common input lever and a first summing lever and a second summing lever;
- and a first and second spool valves;
- the method comprising:
- mounting the first summing lever to a pivot point at a first end and a second pivot point at a second end, wherein the first pivot point and second pivot point allow rotation of the first summing lever in a plane;
- mounting the second summing lever to a pivot point at a first end and a second pivot point at a second end, wherein the first pivot point and second pivot point allow rotation of the second summing lever in the plane;
- attaching the first summing lever to the first spool valve;
- attaching the second summing lever to the second spool valve;
- attaching a first adjustment system comprising a shape memory alloy device to a pivot point of the first summing lever wherein the first adjustment system is in thermal communication with the first spool valve;
- attaching a second adjustment system comprising a shape memory alloy device to a pivot point of the second summing lever, wherein the second adjustment system is in thermal communication with the second spool valve;
- and
- for each summing lever, translating the pivot point attached to the adjustment system in the plane in response to a temperature experienced by each adjustment system.
Dependencies are inferred from the claim text.