Thermal-magnetic switch
AssigneeSangamo Weston, Inc.
InventorJoseph F. Kishel
Life of this patent
Estimating the term…
Abstract
A remotely actuable switch includes a housing defining a cavity having first and second thermally separated chambers, each enclosing a pair of spaced electrical contacts and each having an associated heating element. An electrically conductive fusible element occupies one of the chambers and electrically bridges the spaced contacts therein. To activate the switch the first heating element is activated to melt the fusible element, allowing a Lorentz force resulting from an applied external magnetic field and from current passing between the bridged contacts to expel the melted fusible material from the first chamber into the second chamber. A helical passage may be used as an alternative to a cavity with discrete chambers.
Claims12
A switch comprising:
- a housing defining a cavity having first and second regions communicating with one another;
- a pair of spaced contacts positioned in said first region;
- means for communicating electrically with said contacts;
- an electrically conductive fusible element disposed within said cavity and bridging said contacts when said fusible element is disposed within said first region, said fusible element being in a solid phase at normal operating temperatures of said switch;
- means for melting said fusible element;
- and
- magnet means for setting up a magnetic field in said first region, said field having a component to generate a Lorentz force, when current flows in said fusible element disposed in said first region, urging said fusible element toward said second region.
A switch comprising:
- a housing defining a continuous passage;
- at least three electrical contacts in spaced relationship and disposed within said passage;
- means for communicating electrically with said contacts;
- a fusible element disposed within said passage and electrically bridging at least two but not all of said contacts;
- means for heating said fusible element to its solid phase-to-liquid phase transition temperature;
- magnet means for setting up a magnetic field through at least a portion of said passage, said field having a component to generate a Lorentz force urging said fusible element along said passage, when a electrical current flows in said fusible element.
A switch comprising;
- a housing defining a cavity having first and second chambers communicating with one another;
- a pair of spaced contacts positioned in said first chamber;
- means for communication electrically with said contacts;
- an electrically conductive fusible element disposed in said cavity and bridging said contacts when said fusible element is disposed in said first chamber, said fusible element being in a solid phase at normal operating temperatures of said switch;
- magnet means for setting up a magnetic field in said first chamber to generate a Lorentz force, when current flows between said contacts, urging said fusible element toward said second chamber;
- said fusible element adapted to enter a liquid phase in response to a predetermined current passing between said contacts.
A switch comprising:
- a housing containing a void;
- a pair of electrical contacts positioned in said void;
- a fusible element positioned in said void and in its solid phase at switch operating temperatures;
- a magnet for applying a Lorentz force to said fusible element when current flows through said fusible element, said magnet being oriented to urge said element away from said contacts;
- and
- means for melting said fusible element.
Dependencies are inferred from the claim text.