Abstract: A scissor jack of the type which is mountable on and usable in conjunction with a conventional automotive vehicle lift to permit a selected axle of the vehicle to be elevated relative to the lift. The invention provides a gravity activated locking mechanism which includes a plurality of lock keys of different widths. The keys fall individually into a lock position as the jack rises incrementally in height, to prevent unintended lowering of the jack at any height or any time during the lifting process.

Abstract: A tire changer having a vertical wheel hold down shaft rotatably mounted in a base cabinet and extending upward to a wheel mounting end portion above the cabinet. A collar attached to the hold down shaft beneath its mounting end portion and having a frusto-conical section extending upward to a backing flange centered about the hold down shaft. A locking pin which fits into a wheel lug hole extends upward from the flange. An upwardly extending biased centering cone slidably fitted around the hold down shaft. A bead breaker arm pivotally attached to an outside wall of the cabinet to pivot in a horizontal plane. A pneumatic cylinder is provided which is linked to both the hold down shaft and the bead breaker arm to actuate both, thus providing one pneumatic means for two different functions.