Abstract: A device for sensing overheating of bearings comprises a high-heat-conductivity metallic (copper) sheet adapted for shape-conforming fixed face-contact with an exposed surface of a bearing assemblage. A flat-bottomed brass cup is fixed to the upper surface of the copper sheet, as by pop-type rivets passing through flanges extending laterally from the cup bottom. A snap-disc thermostat lies within and against the bottom of the cup for good heat-exchange with the cup and with the sheet and thus with the bearing assemblage. The cup houses a pair of normally separated switch arms, one of which is engageable by a button of insulating material (attached to the thermostat disc) when the disc snaps to its bearing-overheated position. The device is housed by a piece of plastic tube that snugly embraces the end of the sheath of a two-wire insulated cable electrically connected to the switch.

Abstract: A miniature device for sensing overheating of bearings has a small flat-bottomed circular cup (e.g. fifteen millimeters in diameter) and has an integrally connected co-axial heat-conducting rod extending downwardly from its lower surface for good heat-exchange insertion into a bore made for it in a bearing element. The rod is preferably threaded to improve both its anchorability and its heat-exchange value. A bimetallic snap-disc thermostat lies in and on the bottom of the cup. A small inverted cup of electrically insulating hard plastic has a beaded lip embraced by the crimped rim of the metallic cup to form a housing for a normally closed switch whose spring-arm contact elements are fixed to the inverted plastic cup. An insulating disc closes the bottom of the inverted cup, forms a shallow retaining chamber for the snap-disc, and is centrally axially bored to serve as a guide for an insulating pin by which the thermostat disc operates the switch.