Tobu Electric Co., Ltd.

Chugai Denki Kogyo K.k.

Shigeru Tabei

Seiichi Tanaka

A method for making a bimetallic or trimetallic electrical contact. Features that only its shank portion, made of copper or copper alloy, is covered by a thin layer of silver or silver alloy for protecting the shank portion from environmental erosion. This shank portion is made by cutting the silver-plated wire to a short piece.

Method of making composite electrical contact

A bimetallic or trimetallic electrical contact, only its shank portion being made of copper or copper alloy and being covered by a thin layer of silver or silver alloy for protecting the shank portion from environmental erosion. Said shank portion is preferably made by cutting silver-plated wire to a short piece.

Composite electrical contact

This invention provides a small-size thermal switch having a base formed of an electrically conductive plastic. The thermal switch is arranged such that, after a bimetallic element deflects in a reverse direction and opens the circuit of the thermal switch, the bimetallic element is self-held in such a reversely deflected state and the self-held state of the bimetallic element is maintained until an electrical power source is switched off. This invention further provides a thermal switch in which one surface of its movable-contact leaf spring is maintained in contact with the surface of its bimetallic element which is formed of a metal having the lower coefficient of expansion. Since the bimetallic element is sandwiched between the base and the movable contact, the stability of the bimetallic element in a recess of the base is improved.

Thermal switch

This invention provides a snap-action heat responsive device employing a bimetallic strip which is typically used with a thermostat, a temperature-protecting apparatus or the like. Two elongated portions of the bimetallic strip oppose each other so that they may be deflected in the opposite directions to double the amount of displacement of the bimetallic strip and in addition so that they may be urged in the opposite directions. This enables swift reverse of the bimetallic strip and also production of a small-sized bimetallic device suitable for use as a miniature current limiter for handling an electric current of about one ampere. It is therefore possible to produce a snap-action heat responsive device having a high sensitivity with respect to variations in temperature.

Snap-action heat responsive device

This invention relates to a compact protector which is used to prevent the over-heat of a compact motor used in heat generating appliances such as a hair dryer or electric washing machine. The protector incorporates therein an excess current prevention portion utilizing a bimetal and an excessive temperature rise prevention portion utilizing a temperature fuse. The protector opens an electric path by the double safety devices.

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Machida, Japan

Shigeru Tabei