Dual-functional fuse unit that is responsive to electric current and ambient temperature

摘要

A dual-functional fuse unit, which is responsive to an electric current and an ambient temperature, contains a current sensing fuse and a temperature sensing fuse element. The current sensing fuse is serially connected with and between lead terminals of the fuse unit directly or through an intermediate conductor member. The current sensing fuse or the intermediate conductor member is urged but kept from moving when the temperature sensing fuse element is in a solid state. When the fuse element melts at a specified ambient temperature the urged current sensing fuse or the intermediate conductor member is displaced by the urging force so that the lead terminals are electrically disconnected from each other. In other embodiment, an urged cutter member in the case is normally kept from moving but is driven to sever the element of the current temperature fuse when the temperature sensing fuse element melts at a specified ambient temperature.