Electric short circuit protection for vehicle involved in collision - is esp. for hazardous loads, and uses accelerometer to introduce cut=out with low trip setting

摘要

German traffic regulations prescribe an isolator switch in the driver's cabin which can be used to cut off all electrical circuits in a truck carrying hazardous goods. This switch, is, however, useless if, in case of accidents, a short-circuit is caused before the driver has a chance to operate the switch. This risk can be obviated by connecting the truck chassis (1) to the negative pole (2) of the battery via the contacts (3) of a contactor (4). The coil (5) of the latter is energised by the ignition key G via the N.C. contact (6) of a relay (7). If a collision actuates an acceleration switch (11), the coil (12) is energised, the switch (11) is shunted, and the contactor (4) drops out, to interpose the miniature cut-out in circuit and this allows just enough current to pass to energise the parking lights, but cuts out immediately if the collision has caused a short circuit.