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US 4,306,211 AGranted
Heat operated protective switch
OwnerPeter Hofsassinventor
Life of this patent
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OwnerPeter Hofsassinventor
Estimating the term…
A heat operated protective switch, with a housing, with a bimetallic snap disc guided peripherally in the housing, with a contact adapted to be operated by the bimetallic snap disc, and also with an associated contact. The contact and the associated contact are connected in electrically conductive manner to one another by way of contact surfaces in a low temperature position while when a predetermined temperature is exceeded the bimetallic snap disc snaps over into a high temperature position and lifts the contact away from the associated contact. The contact has a circumferential edge whereby its contact surface coming into contact with the associated contact is set off sharply from the bimetallic disc. Thus operationally caused impairment of the switch-over behavior of the bimetallic snap disc, more particularly impairment caused by switching sparking is obviated.
In a thermal protection switch of the type having a housing, a bimetallic snap-action disc guided within the housing, a first electrical contact, a second cooperating electrical contact, said first contact being actuated by said bimetallic snap-action switch in a manner for placing said contacts in electrically conductive connection with each other and for terminating said electrically conductive connection upon exposure of said bimetallic snap-action switch to temperatures exceeding a predetermined value, the improvement comprising means for preventing switching arcs occurring between said contacts from both damaging or changing the snap-action properties of said bimetallic disc due to contacting of said bimetallic disc by said arc and high strength electrical fields thereof.
Dependencies are inferred from the claim text.