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Internal Air Bearing Accumulator

IP.com Disclosure Number: IPCOM000040111D
Original Publication Date: 1987-Sep-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Haller, KA: AUTHOR

Abstract

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.

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Internal Air Bearing Accumulator

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. In addition, the cavity 3 must then be evacuated to bring the piston back to the preload position, again starving the air bearing and allowing excessive wear to the piston. This piston design lacks the rigidity of a solid frame and is vulnerable to shattering due to the opening at the top of the piston. An alteration to the design of the piston addresses these shortcomings, as described below. The new design is shown in Fig. 2. The top of the piston 1 is closed to provide a more rigid configuration. A check valve 7 has been installed to permit sufficient and reliable airflow to and from the air bearing. Before impact, as the piston is held by the latches for preload, the check valve 7 perm...