| 摘要 |
A compact shock-resistant device may be mounted on a vehicle engine or the like, in thermal contact with engine coolant flow for example, to record an indication of the maximum operating temperature reached during an extended period of use. A tubular housing has threads or the like for mounting in a fluid-retaining wall of the engine with one end being within the fluid and with the other end being accessible at the exterior of the wall. An indicator rod is disposed for axial movement in the housing with one end being visible from outside when a protective cap is removed. Thermally expansible means such as a wax cartridge within the housing exerts a force against the other end of the rod to cause outward movement of the rod when the ambient temperature exceeds the highest temperature previously reached. Spring ratchet means or the like blocks return movement of the rod in the opposite direction. Accordingly, the extent to which the visible end of the rod has increased in length after a period of time is indicative of the maximum temperature reached during that period.
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