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AssigneeNew Nippon Electric Co., Ltd.
InventorsSadayoshi Iwanari, Osamu Umene
Estimating the term…
A thermal fuse comprises an electrically and thermally conductive housing hermetically sealing switch parts of a fusible temperature-sensitive pellet, metallic plates, compression springs and a slidable resilient contact member. The contact member has a center contact portion at its bottom base and a peripheral contact portion with a plurality of tongues extending from the bottom base. The contact member of resilient conductive material is shaped to form a portion sloping over the bottom base and to form peripheral tongues extending relative to the flat surface of the assembled metallic plate when no external force is applied. The shaped contact member with its peripheral tongues has an outer diameter equal to, or smaller than, the inside diameter of the housing when no external force is applied, whereas the application of a biasing force of one of two compression springs to the contact member expands the outer diameter thereof to be larger than the inside diameter of the housing case to maintain a sufficient contact force between the contact member and the housing.
A temperature responsive electric switch comprising:
In a temperature responsive electric switch provided with a thermal fuse comprising a metallic, cylinderical housing having one open end, a first lead-in member electrically secured to said housing, a temperature-sensitive pellet fusible at a predetermined temperature in said housing, retaining plates held opposite to each other by spring means having a comparatively strong resiliency within said housing, a slidable resilient contact member having a central contacting portion and a peripheral contacting portion, a compression spring of comparatively weak resiliency disposed within said housing and between an insulator and said contact member, insulating material hermetically sealing the open end of said housing, and a second lead-in member passing through said insulator and insulating material and having at the tip a contact portion so that the resilient contact member is biased at its peripheral contacting portion against the inner wall of said housing and at the central contacting portion against the contact portion of said second lead member, the improvement wherein said resilient contact member comprises a structure in which the central contacting portion and the peripheral contacting portion are formed as an integral, punched element including a sloped portion between the central portion and the peripheral portion, said integral element having an outer diameter of the peripheral portion equal to or smaller than the inner diameter of said housing, so that the resilient contact member, after insertion into said housing, abuts at the sloped portion thereof against said compression spring, thereby generating a contact pressure force between the peripheral contacting portion and the inner wall of said housing.
A method for making a thermal fuse having, within a housing, switch elements including a temperature-sensitive pellet, a slidable resilient contact member and compression spring means, comprising the following steps:
Dependencies are inferred from the claim text.