The Stilson Wedge Lock Actuator is a pneumatically or hydraulically operated mechanical locking device used to position, lock and pull cores or inserts in injection molding and die cast mold applications.

To understand the basic principles of the Wedge Lock, review the function of an injection mold or a cast die. Injection molding dies are made in two halves. The molds open and close with the aid of guide pins and are held in the close position under extreme force while molten plastic in injected under extreme pressure. Once the mold is filled with the predetermined amount of materials and cools efficiently, the mold is then opened to allow removal of the part. Any hole or embossment that is desirable to the part must be cored. As long as the core is on the center parting line of the mold it will retract as the two halves of the mold are separated to facilitate removal of the parts. If the desired hole or embossment is not on the parting line, the core must be locked in position to withstand the extreme shock of the injection pressure and at the completion of the cycle be retracted prior to the separation of the two halves from the mold.

The Stilson Wedge Lock Actuator was designed to lock, position, and pull cores in plastic and die cast dies, replacing expensive rack and pinion devices and large cylinders. As the Wedge Lock ACtuator is not a clamp but a mechanical lock, and because of its compact size, and the fact that it can hold against a force up to fifty thousand pounds, it is highly sought after as a molding force for staking operations, stamping operations, and as a safety backup for many machining operations. The latest innovation of the Wedge Lock Actuator is the advent of the proximity switches, which signal when the piston is in the extreme forward position indicating that the Wedge Lock has successfully completed a stroke and is in the lock position. Likewise, on the return stroke, the proximity switch will signal the piston has retracted to its maximum position thus indicating that Wedge Lock Actuator has successfully retracted. Engineers have adapted the Wedge Lock Actuator for numerous other applications.