Over-center locking mechanism for tow truck wheel-lift or the like

摘要

The present invention relates to a wheel grid assembly and vehicle towing apparatus. The wheel grid assembly includes a wheel boom and a pair of lift arms. Each lift arm consists of an extension arm segment and an engaging arm segment pivotally mounted to the extension arm segment. Each engaging arm segment is made up of an actuating arm segment and a gripping arm segment extending in different directions from the pivot point. A pair of linear actuators rotate the engaging arm segments about their pivot points to engage the wheels of a vehicle to be towed. Each linear actuator is attached to an engaging arm segment through an over-center locking mechanism. The over-center locking mechanisms lock the engaging arm segments in wheel engaging positions without aid of force from the linear actuators. The present invention also relates to a position lock mechanism and a wheel grid self-centering device. Additionally, the present invention provides a wheel spacer for creating adjustability in the lift arms to accommodate variations in wheel size, and an automatic linear actuator control line retractor assembly. The wheel grid assembly of the present invention may be incorporated with an extensible main boom, and utilized with various configurations of tow vehicles.