Method and apparatus for circulating pallets in an elevator unit of the module IC handler

A module integrated circuit (IC) test handler that includes a pallet circulating apparatus, comprising:

• an elevator unit comprising;
• an elevator elevation plate configured to raise and lower pallets stacked on the elevator elevation plate;
• a stopper unit disposed adjacent to a bottom of said elevator unit comprising a plurality of movable stopper fingers located on sides of the elevator unit outside a path of travel of the pallets when the stopper unit is in an open position, and in the path of travel of the pallets when the stopper unit is in a closed position such that when the stopper unit is in the open position, pallets are allowed to pass the stopper unit as the pallets are raised and lowered by the elevator elevation plate, and such that when the stopper unit is in the closed position, pallets are prevented from passing the stopper unit as the pallets are raised and lowered by the elevator elevation plate and further comprising apertures formed in the elevator elevation plate at positions corresponding to positions of the stopper fingers of the stopper unit such that when the stopper unit is in the closed position, the elevator elevation plate can still pass by the stopper unit;
• a lowering unit disposed adjacent to said elevator unit and configured to lower at least one pallet;
• a transfer apparatus disposed adjacent to a top of said elevator unit and a top of said lowering unit, and configured to transfer a pallet from the top of said elevator unit to the top of said lowering unit;
• and
• a distribution apparatus disposed adjacent to the bottom of said elevator unit and a bottom of said lowering unit, and configured to transfer a pallet from the bottom of said lowering unit to the bottom of said elevator unit.