Browse Prior Art Database

Programmable Three-Finger Gripper

IP.com Disclosure Number: IPCOM000120515D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 78K

Publishing Venue

IBM

Related People

Chu, KL: AUTHOR [+2]

Abstract

This article describes an end-of-arm tool (EOAT) for a robot which picks up a wafer from a wafer-holding fixture and centers it precisely and automatically for processing and places it back after processing.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 56% of the total text.

Programmable Three-Finger Gripper

      This article describes an end-of-arm tool (EOAT) for a
robot which picks up a wafer from a wafer-holding fixture and centers
it precisely and automatically for processing and places it back
after processing.

      The EOAT disclosed herein is shown in top view in Fig. 1.  Fig.
2 is a partial section view across A-A in Fig. 1.  There are three
plastic fingers in the gripper as shown in Fig. 1.  The fingers are
attached to three levers in the gripper.  The fingers open and close
on pivots as shown.  The levers are pushed against three adjustment
set screws by three light springs.  The set screws are calibrated
such that the three fingers touch the edge of the wafer
simultaneously.

      A linear stepping motor is used to control the opening and
closing of the fingers.  The linear stepping motor provides a direct
linear motion in the Z axis by means of a rotating nut (not shown)
and a lead screw inside the motor. The linear motion of the lead
screw is programmed by a micro-stepping control technique and the
resolution of the linear motion is accurate within one micron.  The
linear stepping motor is connected to a motor block with the three
set screws in it.  When the motor block moves in the downward
direction along the Z axis, the set screws turn the levers outward
and open the fingers.  When the motor block moves in the upward
direction along the Z axis, the set screws turn the levers inward and
close the finger...