Automatic arm restraints are needed to keep the arm “locked” into a position relative to the carriage. When the arms are at rest in the lowest position, the arm restraint pin (which extends below the carriage) is pressed up and the lock (teeth) mechanism is disengaged.
The operator can then move the arms so that the lift pads can be properly positioned under the vehicle’s lift points. Once the carriage is raised (approximately 2 inches) the lock is reengaged and the arms cannot be moved. However, the operator may pull the knob or metal ring to manually unlock the arms. Lock restraints do not guarantee that a vehicle cannot be “moved” off of the lift pads. Operator should use care when working on vehicles that have an abundant amount of undercoating (lift pads may “slide”) or a significant weight imbalance of the vehicle may occur due to removal of an engine or transmission. Also, “HEAVY wrenching” may result in a vehicle shifting weight on the arm pads. We recommend the use of tall jack stands under the vehicle to add another layer of safety.