Browse Prior Art Database

Two Point Line Gripper for Cylinder Objects

IP.com Disclosure Number: IPCOM000045325D
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Buchholz, MH: AUTHOR

Abstract

A gripping device has two opposed pairs of point contacts whose spans are orthogonal to each other for enabling a cylinder to be gripped in either of two orthogonal orientations. One pair of contacts engages the cylinder surface along a line parallel to its axis, while the other contacts engage the surface at two points on a circumferential line around the cylinder orthogonal to its axis. Thus, if the cylinder is presented to the gripper in a 901/4 rotated orientation, it is gripped in a similar manner but with the roles of the pairs of contacts interchanged.

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Two Point Line Gripper for Cylinder Objects

A gripping device has two opposed pairs of point contacts whose spans are orthogonal to each other for enabling a cylinder to be gripped in either of two orthogonal orientations. One pair of contacts engages the cylinder surface along a line parallel to its axis, while the other contacts engage the surface at two points on a circumferential line around the cylinder orthogonal to its axis.

Thus, if the cylinder is presented to the gripper in a 901/4 rotated orientation, it is gripped in a similar manner but with the roles of the pairs of contacts interchanged.

The principles are illustrated in Fig. 1 in which the gripper has two clamping fingers 10 and 11. On each finger are two point contacts 12, 13 and 14, 15. Motion of the gripper fingers is indicated by lines 20. It can be seen that in either of the orientations shown, a cylinder 21 is gripped and constrained kinematically by a line contact and two point contacts. Since cylinder 21 can be gripped along two different axes, the gripper can also orientate the cylinder rotationally about these axes by using the last axis of rotation on a robot. The need for multiple grippers for different cylindrical parts presented in the two orientations is eliminated.

When held by such a gripper device, the center of the cylinder is not midway between the fingers and the displacement is different depending on which pair of contacts are the axial ones. The off-center error x can be cal...