Shape memory alloy relays and switches

An electrical switch comprising:

• at least one electrical contact:
• a support:
• an elongate member comprising a shape memory alloy and having two ends, said elongate member being attached at either end to said support;
• a switch element made of an electrically-conductive material, said switch element being attached to said elongate member at a location intermediate the two ends of the elongate member;
• and
• heating means for selectively heating the elongate member such that said elongate member moves causing said switch element to move into or out of contact with said at least one electrical contact;
• wherein said heating means includes at least two optical members, a first of which is positioned proximate a first portion of said elongate member and is operable to heat said first portion and the second of which is positioned proximate a second portion of said elongate member and is operable to heat said second portion of said elongate member.

An electrical switch comprising:

• at least one electrical contact;
• a support;
• an elongate member comprising a shape memory alloy and having two ends, said elongate member being attached at either end to said support;.
• a switch element made of an electrically-conductive material, said switch element being attached to said elongate member at a location intermediate the two ends of the elongate member:
• and
• heating means for selectively heating the elongate member such that said elongate member moves causing said switch element to move into or out of contact with said at least one electrical contact:
• wherein said heating means comprises at least one high-resistivity wire that is positioned proximate said elongate member and provided with at least one electrical connection to which electrical current may be selectively applied;
• wherein said at least one electrical connection includes three electrical connections, the first electrical connection being positioned proximate one end of said elongate member, the second electrical connection being positioned proximate the other end of said elongate member, and the third electrical connection being positioned proximate the point where said switch member is attached to said elongate member.

An electrical switch comprising:

• a support assembly, said support assembly having a first substantially flat portion, a second substantially flat portion positioned opposite said first flat portion, and two opposing side portions positioned between said first and second flat portions;
• at least one electrical contact mounted to said support assembly;
• an elongate member comprising a shape memory alloy and having two ends, each one of said ends of said elongate member being attached to respective ones of said two opposing side portions of said support assembly, said elongate member extending along a substantially straight path from one of said two ends to the other of said two ends;
• a switch element made of an electrically-conducting material, said switch element being attached to said elongate member at a location intermediate the two ends of said elongate member;
• and
• at least one heater that can be selectively operated to heat said elongate member such that said elongate member moves causing said switch element to move into or out of contact with said electrical contact.

An electrical switch comprising:

• at least one electrical contact;
• a support assembly;
• an elongate member comprising a shape memory alloy and having two ends, said elongate member being attached at either end to said support assembly;
• a switch element made of an electrically-conducting material, said switch element being attached to said elongate member at a location intermediate the two ends of said elongate member;
• and
• at least one heater;
• wherein said heater can be selectively operated to heat said elongate member such that said elongate member moves causing said switch element to move into or out of contact with said electrical contact, said heater comprising at least one high-resistivity wire, positioned proximate said elongate member, to which electrical current may be selectively applied;
• and
• wherein said at least one high-resistivity wire is twisted about said elongate member.

An electrical switch comprising:

• a first support member;
• a support assembly coupled to said first support member;
• a first electrical contact mounted to said first support member;
• an elongate member comprising a shape memory alloy and having two ends, said elongate member being attached at either end to said support assembly, being twisted about a longitudinal axis of said elongate member, and extending along a substantially straight path from one of said two ends to the other of said two ends;
• a switch element made of an electrically-conducting material, said switch element being attached to said elongate member at a location intermediate the two ends of said elongate member;
• a second support member coupled to said support assembly such that said support assembly is disposed between said first and said second support member;
• and
• heating means for selectively heating said elongate member such that said elongate member moves causing said switch element to move into or out of contact with said first electrical contact.

An electrical switch comprising:

• a first support member;
• a support assembly disposed adjacent said first support member;
• a first electrical contact mounted to said first support member;
• an elongate member comprising a shape memory alloy and having two ends, said elongate member being attached at either end to said support assembly;
• a switch element made of an electrically-conducting material, said switch element being attached to said elongate member at a location intermediate the two ends of said elongate member;
• a second support member positioned adjacent said support assembly such that said support assembly is disposed between said first and said second support member;
• a second electrical contact mounted to said second support member;
• and
• heating means for selectively heating said elongate member such that said elongate member moves causing said switch element to move into or out of contact with said first electrical contact;
• wherein said first electrical contact is positioned on said first support member such that at least a portion of said first electrical contact is substantially opposite a first end of said switch element and said second electrical contact is positioned on said second support member such that at least a portion of said second electrical contact is substantially opposite a second end of said switch element, whereby said heating means is operable to selectively heat said elongate member such that the first end of said switch element may be brought into or out of contact with said first contact and said second end of said switch element may be brought into or out of contact with said second contact.

An electrical switch comprising:

• a first support member;
• a support assembly disposed adjacent said first support member;
• a first electrical contact mounted to said first support member;
• an elongate member comprising a shape memory alloy and having two ends, said elongate member being attached at either end to said support assembly;
• a switch element made of an electrically-conducting material, said switch element being attached to said elongate member at a location intermediate the two ends of said elongate member;
• a second support member positioned adjacent said support assembly such that said support assembly is disposed between said first and said second support member;
• and
• heating means for selectively heating said elongate member such that said elongate member moves causing said switch element to move into or out of contact with said first electrical contact;
• wherein said heating means comprises a first heating source positioned in said first support member and a second heating source positioned in said second support member.

An electrical switch comprising:

• a first support member;
• a second support member disposed adjacent said first support member;
• a first electrical contact mounted to said first support member;
• an elongate member comprising a shape memory alloy and having two ends, said elongate member being attached at either end to said second support member;
• a switch element made of an electrically-conducting material, said switch element being attached to said elongate member at a location intermediate the two ends of said elongate member;
• and
• heating means for selectively heating said elongate member such that said elongate member moves causing said switch element to move into or out of contact with said first electrical contact;
• wherein said second support member has a substantially "U" shape with two opposing legs, and wherein one end of said elongate member is attached to one leg of said second support member and the other end of said elongate member is attached to the other leg of said second support member.