Abstract: The present invention relates to an actuating mechanism for actuating the moving contact of a protective interrupting chamber which is installed on a high-voltage or medium-voltage power line and which is to be opened when a current in excess of a surge current threshold flows through line, the mechanism including a drive member for driving a displacement device for displacing the contact. The drive member is a conductive helical spring made of a shape memory alloy and electrically coupled to the line, a current in excess of said surge current threshold passing through the spring heating said spring to such an extent that said alloy goes from its martensitic phase to its austenitic phase. The mechanism enables the interrupting chamber to be re-closed by means of a sequencer device associated with the displacement device, and providing an adjustable and timed opening and closing cycle.

Abstract: A trip-free mechanism for resetting an on-off unit, such as a thermostat (1), breakable by the tripping of an actuator element (3) from a first condition to a second condition comprises a resetting button (9) engageable to apply a resetting force to the actuator element (3) to reset the latter in its first condition, and a restraining lever (10) acted upon by the resetting button (9) when it applies the resetting force to the actuator element (3) to maintain the unit in its broken condition until the button (9) is disengaged upon resetting of the actuator element.

Abstract: The invention is directed to an overcurrent-protective switch for household appliances such as a vacuum cleaner. The snap switch has a housing in which a contact mounting unit is mounted at one end of the housing and contains one of two current terminals of the switch. The other current terminal is mounted at the other end of the housing and is configured to define a contact-engaging surface. A resilient interrupting contact member is fixedly connected to the one current terminal and has a metal center strip by means of which it is held in one of two end positions. In the first end position, the contact member is held in contact engagement with the contact-engaging surface of the other current contact terminal and, in the second end position, it is disengaged from the contact-engaging surface. When the center resistance strip is cool, the contact member is in its first position and the current circuit between the two current terminals is closed.

Abstract: A base body with a big cavity in its center, a frame body encased in the cavity and retained therein by the ends of the shorter legs of the U-shaped contact plates is disclosed. During an overload condition, overheating causes a spring engaging the clipper plate to expand, which frees the frame body from the shorter legs of the contact plates and the frame body is ejected upward by a coil spring inside the frame body. The frame body is detained in the cavity of base body when freed from the shorter legs of the contact plates by engagement between flanges on frame body and the ends of the longer legs of the U-shaped contact plates, and an LED trouble indicator is used to indicate the overload condition.

Abstract: A disconnect switch or hot wire relay for use with a ground fault circuit interrupter in a power circuit to a load, such as an electric range, to provide ground fault protection for any circuit of the range. The switch has normally closed switch contacts, a biased actuator plunger for opening the contacts, a latching member for disabling the plunger, and an adjustable hot wire for releasing the latch and hence the plunger when the circuit is overloaded. The plunger of the switch is manually resettable from a remote position. The reset mechanism has an anti-tease or trip-free feature which prevents the operator from holding the disconnect contacts closed while a fault is present in the circuit.

Abstract: An adjustable time delay disconnect switch or hot wire relay for use with a ground fault circuit interrupter in a power circuit to a load, such as an electric range, to provide ground fault protection for any circuit of the range. The switch has normally closed switch contacts, a biased actuator plunger for opening the contacts, a biased latch for disabling the plunger, and an adjustable hot wire for releasing the latch and hence the plunger when the circuit is overloaded. The plunger is manually resettable when the circuit condition returns to normal.