Internal Air Bearing Accumulator
Original Publication Date: 1987-Sep-01
Included in the Prior Art Database: 2005-Feb-01
A manual impact pinner uses air and vacuum, successively, to drive a piston to impact substrate pins. The piston 1 (Fig. 1) has a top opening 2 to admit air into the piston cavity 3. The air exhausts through exit holes 4 in the piston wall 5, providing an air bearing between the piston wall 5 and the cylinder wall 6. During preload of the piston 1 before impact, the piston is held in place by latches (not shown). When the latches release the preloaded piston, a large pressure drop occurs above the piston and most of the air in the cavity 3 is drawn (Image Omitted) out through the top opening 2. This causes an insufficient air supply to the bearing. The piston becomes scored from contact with the cylinder wall and fails due to the excessive wear.