Abstract: A toy vehicle has a gear box containing a clock spring which is wound by pushing the vehicle backward. A two part toggle-linkage system connects the gear box to the frame. When the clock spring is wound, the resulting spring bias urges the toggle-linkage system to one over center position which locks the gear box in order to preserve the energy stored in the wound spring. When the toggle-linkage system is pressed near its center, it moves over center to another position, which unlocks the gear box and releases the energy stored in the wound spring in order to propel the vehicle. When the vehicle is next moved backward, the toggle-linkage returns to the locked position which once again locks the gear box.