Abstract: The present invention teaches an overvoltage protection device that includes at least one non-linear resistance element and a single cut-off device coupled with the at least one non-linear resistance element to disable the at least one non-linear resistance element when the at least one non-linear resistance element reaches a pre-determined temperature. The single cut-off device may include stranded wire, a first solder having a first melting point connecting the stranded wire to the at least one non-linear resistance element, and a second solder having a second melting point, higher than the first melting point, connecting the stranded wire to the at least one non-linear resistance element. The single cut-off device may further include a shifting part that shifts when the at least one non-linear resistance element heats the first solder to the first melting point.

Abstract: A thermal switch comprises an elongate tubular sealed housing. A control circuit is mounted in the housing. The control circuit comprises a thermostat, a fuse and a thermal overload switch electrically connected in series. An electrical connector is mounted to the housing and is connected to the control circuit.

Abstract: A protective device for minimizing fire danger in the use of electrical circuits comprises a unit having a mechanically biased conductive element in series with the circuit, and maintained in position under tension by a fusible material such as a Cerro alloy having a yield point at a selected temperature threshold. When overheating at some other point in the circuit results in a rise of temperature at the protective device, the yielding of the fusible material allows the conductive element to spring free, opening the circuit and cutting off the current. This arrangement is useful in a male plug integral to or separate from an extension cord or power cord, in conjunction with circuit breaker systems, in a in-circuit device, and in electrical appliances and devices.

Abstract: A power circuit breaker has a housing, a fuse element placed in the housing, and a temperature sensitive fuse attached to the fuse element. The fuse element has tab terminals extending from both ends, which are received by trunk terminals connected to an external circuit. The temperature sensitive fuse has a blowout temperature lower than that of the fuse element. The power circuit breaker also has transistors connected to the temperature sensitive fuse. An igniter is placed below the fuse element in the housing, and one of the transistors is connected to the igniter. The temperature sensitive fuse blows out when an excessive current flows through the fuse element, and one of the transistors connected to the igniter is turned on upon the blowout of the temperature sensitive fuse. A gas is jet from the igniter upon turning on the transistor, whereby the tab terminals of the fuse element are disconnected from the trunk terminals.

Abstract: A power plug includes a plug body having opposite sides and an end, terminal prongs extending from the end of the plug body, and a built-in circuit breaker. The circuit breaker is operable between a normal condition enabling the power plug to connect a load to a power source and a tripped condition disconnecting the load upon the detection of a circuit fault. The circuit breaker includes at least two members at respective opposite sides of the plug body which are simultaneously movable between a first position corresponding to the normal condition and a second position corresponding to the tripped condition. The members provide an indication of the operating condition of the circuit breaker viewable on both sides of the plug body.

Abstract: A protective device for minimizing fire danger in the use of electrical circuits comprises a unit having a mechanically biased conductive element in series with the circuit, and maintained in position under tension by a fusible material such as a Cerro alloy having a yield point at a selected temperature threshold. When overheating at some other point in the circuit results rise of temperature at the protective device, the yielding of the fusible material allows the conductive element to spring free, opening the circuit and cutting off the current. This arrangement is useful in an male plug integral to or separate from an extension cord, in conjunction with circuit breaker systems, in a in-circuit device, and in electrical appliances and devices.

Abstract: An electrical switch includes a body having one open end exposed for adaptation of a pyrotechnic cartridge and the other end sealed by the base of a pin type connector assembly having short conductive pins and elongated conductive pins with relief areas containing insulative material. The pins are inserted into the body cavity. A conductive grounding plate or plates have tabs which bite into the pins and connect selected pins in a first operational state. A plunger having fracturable bosses is located adjacent the contact plate. Upon activation of a pyrotechnic cartridge, pressure is applied to the plunger, causing fracture of the bosses and resulting in the displacement of the plunger to move the contact plate to a different position thereby changing the number of closed circuits.

Abstract: A control apparatus is disclosed for regulating the movement of a control stem which is biased in a given direction. The apparatus comprises a housing forming a chamber and a plurality of passages. The chamber receives the control stem in its direction of bias, the latter abutting against a restraining sphere disposed in the chamber. A pair of pistons are movably disposed in remaining ones of the passages to maintain the sphere in the chamber. The pistons are movable to allow the sphere to enter a passage so that the stem can move further into the chamber. The pistons can be moved manually or automatically, as by means of a fusible element which melts in response to the heat of a fire.

Abstract: The invention is directed to an arrangement for detecting deficient operational capability in a vacuum switching vessel. The arrangement can provide a signal if a fault occurs which affects the operability of the switching vessel. Instead of a signal, a protective device alone or together with the signal can also be caused to respond. The arrangement includes a body of a material which changes its physical characteristics substantially in a limited temperature interval and is attached in heat-conducting contact with a part of the vacuum switching vessel which has a temperature time constant as small as possible. This change of the characteristics of the body acts to initiate the above-mentioned signal or action of the protective device. The invention is suited particularly for application in switchgear with vacuum switching vessels.