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US 6,133,816 AGranted
Switch and relay using shape memory alloy
AssigneeRobertshaw Controls Company
InventorsGregory Barnes, Jon Skekloff, David D. Martin, Douglas Ray
Life of this patent
Estimating the term…
Abstract
A novel shape memory alloy electrical switch is disclosed, including both momentary and especially a latching relay. The switch/relay disclosed is particularly useful in low power control of appliances, including i.a. refrigerators. Used with a microprocessor, microcontroller, or like device to control the shape memory alloy switch/relay, an adaptive control routine may be included which facilitates an especially low-power dissipation, highly effective appliance control module, especially suitable for refrigerators. The disclosed refrigerator control module can be manufactured at low cost with high reliability.
Claims31
An electrical switch, comprising:
- an elongated shape memory alloy actuator having a first portion and a second portion;
- a switching arm, coupled to the first and second actuator portions, the switching arm having first and second positions;
- a first electrical contact;
- a second electrical contact connected to the switching arm, and disposed to be electrically isolated from the first electrical contact when said switching arm is in the first position and disposed to be electrically connected to the first electrical contact when said switching arm is in the second position;
- a first electrical path for applying an electrical current through the first portion of the actuator;
- and
- a second electrical path for applying an electrical current through the second portion of the actuator;
- wherein at least one of the first and second electrical paths includes at least a portion of the switching arm.
5 more elements
An electrical switch, comprising:
- an elongated shape memory alloy actuator having a first portion and a second portion;
- a switching arm, coupled to the first and second actuator portions, the switching arm having first and second positions;
- a first electrical contact;
- a second electrical contact connected to the switching arm, and disposed to be electrically isolated from the first electrical contact when said switching arm is in the first position and disposed to be electrically connected to the first electrical contact when said switching arm is in the second position;
- a first electrical path for applying an electrical current through the first portion of the actuator;
- a second electrical path for applying an electrical current through the second portion of the actuator;
- a first control switch for passing an electric current through said first electrical path;
- a second control switch for passing an electric current through said second electrical path;
- and
- wherein each of the first and second control switches includes an SCR.
7 more elements
A method of switching an electrical load current, comprising:
- providing an elongated shape memory alloy actuator having a first portion and a second portion;
- providing a switching arm coupled to the first and second actuator portions;
- applying an electric control current through one of the first and second portions and at least a portion of the switching arm;
- decreasing the length of said one of the first and second portions when said electric control current passes therethrough;
- moving the switching arm from one of the first and second positions to the other of the first and second positions;
- electrically isolating a first electrical load contact from a second electrical load contact when the switching arm is in a first position;
- and
- electrically connecting the first electrical load contact to the second electrical load contact when the switching arm is in a second position.
5 more elements
An electrical switch, comprising:
- an elongated shape memory alloy actuator having first and second substantially straight portions disposed at a substantially right angle to each other;
- a switching arm, coupled to the first and second actuator portions, the switching arm having first and second positions;
- a first electrical contact;
- a second electrical contact connected to the switching arm, and disposed to be electrically isolated from the first electrical contact when said switching arm is in the first position and disposed to be electrically connected to the first electrical contact when said switching arm is in the second position;
- a first electrical path for applying an electrical current through the first portion of the actuator;
- a second electrical path for applying an electrical current through the second portion of the actuator;
- and
- wherein a linear dimension of the first portion is shorter when a temperature of the first portion exceeds a predetermined temperature and a linear dimension of the second portion is shorter when a temperature of the second portion exceeds the predetermined temperature.
5 more elements
Dependencies are inferred from the claim text.