They are used every day in garages so often that the dangers for working-safety can easily be overlooked. After all, the mechanic moves around under a vehicle the same as he does in the rest of the garage. It gets really dangerous when backyard mechanics scramble about under their vehicles and thus entrust their lives possibly, to only one ramshackle chock. Or perhaps a really stable looking brick...
One cannot stress often enough: The most important criterion for the support, is the permissible load. It may of course, under no circumstances, be exceeded, in fact, as seen in the above example, in certain cases, it must be reduced considerably. It then depends on the security of the safety chocks. On which surface is it standing, and which movements it makes while working on the vehicle.
With the hoist it is all about the security bolts which must be locked into place, and about suitable points in which the arms grip the vehicle. Important is also, the influence that the hoisting platform has on the vehicle. Is the basic approach wobbly, or can the car roll off the platform? Apart from that, there is also perhaps, weight misalignment to be thought of, for example, when removing the engine.
Because hoisting equipment is as complicated, at least technically, as some trailers, it must also be examined by the safety-standards-authority (roadworthy-test) regularly, this means every year, with an entry in a testing log-book. Hoists are treated by the traffic legislation authorities almost like truck brakes. Also, persons may not be raised higher than 1 meter without suitable measures being taken. Unfortunately, you sometimes see on television also members of the automotive business, so actually professionals, climb with ladders in vehicles on the auto hoist.
In addition, the demands on the operating staff are considerable. They must be trained, and if under 18 years of age, work only under supervision. One single exception is interesting. If the vehicle is raised for the purpose of wheel-changing, one can dispense with additional safety measures. The reason for this may lie in the jacking-equipment of some vehicles. Nevertheless, one should, if possible, not try to do without a second safety chock. 12/14