Patent ID: 8192192

Claim:
A mechanical safety device for an injection molding machine, the injection molding machine comprising at least a movable platen and a stationary platen on a base and a mechanism for performing a mold opening/closing operation for the movable platen, the mechanical safety device comprising a laterally openable safety door on the flank of a mold opening/closing portion between the movable platen and the stationary platen, the mechanical safety device further comprising: a rod secured to the stationary platen or the base; a rail assembled to the rod and configured to ascend and descend as the safety door is closed and opened; and a ratchet rotatably supported on a prop on the movable platen, the ratchet being configured to pivot around the central axis of the prop and being moved up when the rail is lifted up relative to the base; wherein the rod is formed with a plurality of engaging step portions and tapered surfaces alternately arranged at regular intervals, and the rail is configured to ascend or descend to push up or down the ratchet, thereby locating the ratchet in a first position where the ratchet engages with the engaging step portions of the rod or a second position where the ratchet is disengaged from the engaging step portions.