OVERHEATING PROTECTION DEVICE FOR ROTATIONAL CONTROL APPARATUS

摘要

A device (110) for protecting a clutch (C) against overheating from externally caused problems such as rapid cycling is disclosed including a heat conductive plug (120) sealed in an escape port (116) of a fitting (112) by fuse material (124) such as lead. The fitting (112) is threadably, sealably received in a bore (104) formed in the friction interface disc (12) of the clutch (C). The bore (104) is in fluid communication with the cylinder (30) of the clutch (10) which slideably mounts a piston (10) connected to the friction interface disc (12). Fluid pressure introduced into the cylinder (30) by conventional conduit means (42) moves the piston (10) therein against the bias of a spring (56) when fluid flow from the cylinder (30) through the bore (104) is blocked by the overheating protection device (110). When heat resulting from clutch temperatures exceeding normal operating temperatures and conducted to the fitting (112) and the device (110) is sufficient to melt the fuse material (124), the plug (120) is ejected from the escape port (116) by the fluid pressure communicated from the cylinder (30) to the bore (104). The fluid pressure of the cylinder (30) will be insufficient to move the piston (10) against the bias of the spring (56) when the escape port (116) is not sealed by the plug (120) and fuse material (124).