General Electric Company

Ronald W Kelly

Kennett R Fuller

Raphael A Gonzalez

Paige W Thompson

An electrical contact comprises a body formed of a precious metal in which the precious metal defines a contact surface of the body. At least one projection of the precious metal is formed generally centrally of the contact surface so as to extend therebeyond by successive discrete extrusions of the precious metal into a preselected configuration comprising the projection. A free end portion on the projection is spaced from the contact surface and comprises a chordal section of a sphere.

Electrical contact having a precious metal extrusion extending from a

A constant-on variable-stroke refrigeration thermostat is disclosed wherein the toggle spring-biased operating lever has a fixed-position stop when the contacts are open and a variable-position stop when the contacts are closed, and wherein an air gap is provided between the actuator prong of the operating lever and the moveable contact blade of the switch contacts to allow the operating lever to travel downwardly with increased momentum before the switch contacts are opened. The primary advantage provided by the present invention is that the thermostat is of a much simpler construction, which results in a lower cost and a higher reliability.

Constant-on, variable-stroke refrigeration thermostat

A condition responsive switching apparatus with an alarm feature for use in refrigeration appliances, such as freezers or the like. The switching apparatus includes a contact operator which moves between first, second, and third positions in response to the pressure changes of a bellows. The bellows pressure increases and decreases in response to changes in temperature sensed at the appliance. The apparatus includes a first set of control contacts to provide energization of a compressor and a second set of alarm contacts to provide energization of an alarm circuit. The contact operator has a first dog which opens and closes the control set of contacts as the operator moves through a snap action increment of travel between the first and second positions. An alarm spring opposes the travel of a second dog of the contact operator beyond the second position with a preload force until the excess of the snap action energy of the operator is dissipated. The alarm spring, thereafter, opposes the contact operator with a spring gradient until the operator reaches the third position and closes the alarm contacts. The closure of the alarm contacts causes the energization of an alarm circuit which signals that the appliance temperature is in excess of the cycling temperature and that the failure of a system component is likely to have occurred.

Condition responsive switching apparatus

A method of fabricating an electrical contact formed at least in part of a precious metal which defines a contact surface on the electrical contact. In this method, an initial discrete deformation of the precious metal extends a projection of the precious metal to a first preselected height beyond the contact surface. Thereafter a further discrete deformation of at least the precious metal projection forms it into a preselected configuration and also alters the extension of the precious metal projection to another preselected height beyond the contact surface different than the first preselected height.

Methods for fabricating an electrical contact

A temperature responsive electrical switch device has means operable generally for switching between a pair of switching means, and temperature responsive means is operable generally at a set-point temperature for effecting the operation of the switching means. Means is linearly movable in response to an applied force exerted thereon and arranged in camming engagement with an associated part of the temperature responsive means for setting the set-point temperature.

Temperature responsive electrical switch device

A condition responsive electric switch system comprises switch means which includes at least one set of contact elements defining a preselected open position, a preselected closed position, and a preselected initial contact make-break position, disposed between the open and closed positions. Switch actuating means is movable in actuating relation with the switch means for operating the contact elements selectively into and out of the three preselected positions. Spring means and temperature responsive means are connected to and impart motion to switch actuating means, with the spring means and temperature responsive means creating opposing forces on the switch actuating means. The condition responsive electric switch system has both positive and negative spring gradients including a force producing means having maximum absolute positive gradient forces F.sub.1 and F.sub.2 in which F.sub.1 =maximum absolute positive gradient pre-load force on the contact elements at the preselected initial contact make-break position; F.sub.2 =maximum absolute positive gradient force on the contact elements at the preselected closed position wherein the value of the expression (F.sub.2 -F.sub.1)/F.sub.2 should not be substantially less than unity. A net contact element force is also produced generally in the vicinity of zero as the contact elements pass at least through the preselected initial contact make-break position. The system further includes means for adjusting the larger negative spring gradients in the system. An electrical switch device and a method of operating the switching device are also disclosed.

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Morrison, IL, United States of America

Ronald W Kelly