Abstract: A switching device (FIGS. 5 A and 5B) employs as actuator a bistable solenoid which includes a plunger (16) movable within a winding (12) between end positions in each of which it is held by permanent magnets (18, 20). The plunger (16) of the actuator is engageable with an insulated lever (86) which in turn actuates a contact blade (76) via a spring (108). The lever may be cranked, and may have an extension (90) outside of the casing (70) to enable the device to be manually operated or to provide a visual indication of the state of the switch. Other types of solenoid may be employed as the actuator.

Abstract: A solenoid actuator has an external casing comprising a part 16 mechanically drawn from a mild steel work piece and a second part in the form of a machined, screw threaded bush 20 welded to the drawn part 16. The part 16 is mechanically drawn to incorporate means such as a nut 18 by which the actuator can be threaded in to engagement with a complementary structure. In the case of a diesel engine, for example, the actuator may form a fuel cut off valve when mounted to the diesel engine valve casting.