A control for moving a pallet relative to first and second base plates including four carriages that are rotatably supported on the second base plate by second rollers and which can be moved by pistons that are mounted in cylinders that are attached to the second base plate. The first plate has downwardly extending members formed with slanted slots and each of the four carriages have first rollers received in the slots so that as the pistons are moved in the cylinders the first base plate and the pallet are raised and lowered relative to the second base plate. Third rollers are mounted between the pallet and the first base plate so that they are movable relative to each other.
An automatic pallet changer system in an automatic machining center has a first track for receiving a first pallet having a first workpiece thereon, and a second track for receiving a second pallet having a second workpiece thereon. The first and second tracks are side-by-side and extend from a region outside the enclosure to a region inside the enclosure adjacent the receiver. A linear drive unit is arranged between the first and second tracks and has a carriage which moves along a longitudinally extending carriage guide. The carriage has a member for engaging with the first or second pallet depending upon whether the linear drive unit is rocked to the left or to the right. A motor is connected to the linear drive unit for causing a movement of the carriage along the carriage guide. A rocker unit is connected to the linear drive unit for rocking the linear carriage unit to the left or to the right. A programmable logic control automatically controls overall operation of the system including the linear drive unit and detecting positions of the first or second pallet either within the machining enclosure or at the end of the linear drive unit adjacent the rocker unit.
An apparatus for elevating a workpiece includes a transfer bar movable between a first position and a second position, and a support member having a cam surface with a first end and a second end. The cam follower is engageable with the cam surface for supporting the transfer bar with respect to the support member as the cam follower moves along the cam surface between the first end and the second end. When the transfer bar is in the first position, the cam follower is adjacent the first end of the cam surface. When the transfer bar is in the second position, the cam follower is adjacent the second end of the cam surface. A driving mechanism is provided for moving one of the cam follower and the cam surface relative to one another between the first end and the second end of the cam surface. The elevating apparatus can be used in a multi-station machining line where at least one workpiece to be machined is transported on at least one transfer bar from one station to another. The transfer bar is elevated to a first position for transportation of the workpiece between the stations, and is lowered to a second position when the workpiece reaches a station.
