Method of making a circuit protector
AssigneeCooper Industries, Inc.
InventorLeon Gurevich
Life of this patent
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Abstract
A subminiature circuit protector includes a substrate carrying a metal fuse element hermetically sealed in a glass sleeve cartridge. The fuse element may comprise a film deposited on the substrate, or, alternatively a metal strip or wire. Leads extend from opposing ends of the sleeve for connection in a circuit, and a gas is sealed in the sleeve to provide a suitable environment to improve operating lifetime and interrupting capability. A method for making a circuit protector includes placing a substrate carrying a fuse element in a glass sleeve and placing leads in contact with the fuse element. The assembly is heated in the presence of a gas below atmospheric pressure to a temperature sufficient to soften the glass. The pressure is then increased to cause the ends of the glass sleeve to form a hermetic seal about the leads.
Claims12
A method for making a circuit protector, comprising the steps of:
- inserting a substrate carrying a fuse element and having electrical contacts at opposing end portions in a glass sleeve, the glass sleeve having open ends;
- positioning one lead at each end portion of the substrate in contact with the electrical contacts;
- placing the assembly in a pressure and temperature controllable chamber;
- at least partially evacuating the chamber;
- heating the chamber to heat the assembly to a temperature sufficient to soften the glass sleeve so that the ends of the glass sleeve adhere to the leads;
- and,
- increasing the pressure to a pressure sufficient to cause the ends of the softened glass sleeve to form a hermetic seal around the leads.
Dependencies are inferred from the claim text.