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Bearing Self Alignment System for Cartesian Robots

IP.com Disclosure Number: IPCOM000108194D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Related People

Kroeker, TR: AUTHOR

Abstract

Disclosed is a system to maintain correct alignment of linear bearings on large cartesian coordinate robots having fabricated frames. When the working envelope of a cartesian coordinate robot becomes large, it is no longer practical to machine the frame from one piece such as a casting. If a robot is installed in another structure, such as a glove box, a one-piece frame is not possible. Large robot frames must be fabricated from several sections. The linear bearings must be mounted on the frame so they are parallel, separated by the correct distance, and in the same plane. If the bearings are not aligned parallel and in the same plane, the bearings can bind and overload the motors and/or the bearings. Misalignment can also deflect or deform the robot frame. Distortion of the frame will affect the repeatability of the robot.

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Bearing Self Alignment System for Cartesian Robots

      Disclosed is a system to maintain correct alignment of linear
bearings on large cartesian coordinate robots having fabricated
frames.  When the working envelope of a cartesian coordinate robot
becomes large, it is no longer practical to machine the frame from
one piece such as a casting.  If a robot is installed in another
structure, such as a glove box, a one-piece frame is not possible.
Large robot frames must be fabricated from several sections. The
linear bearings must be mounted on the frame so they are parallel,
separated by the correct distance, and in the same plane.  If the
bearings are not aligned parallel and in the same plane, the bearings
can bind and overload the motors and/or the bearings.  Misalignment
can also deflect or deform the robot frame.  Distortion of the frame
will affect the repeatability of the robot. This system does not
depend on precise alignment of the linear bearings but on the
self-alignment of one bearing. One bearing will align itself parallel
and in the same plane as the other.  The master bearing is mounted
rigidly on one side of the frame.  The other bearing is mounted on
leaf springs on the opposite side of the frame.  The leaf springs
allow the bearing to move small distances closer to, or further away
from, the master bearing.  This compensates for small errors in the
distance between the bearings and for any the amount the bearing are
not in parallel.  The leaf...