Browse Prior Art Database

Robotic End Effector Overload Protection Device

IP.com Disclosure Number: IPCOM000108771D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 3 page(s) / 105K

Publishing Venue

IBM

Related People

Ellis, J: AUTHOR

Abstract

Disclosed is an overload protection device for a robotic end-effector (end-of-arm tool).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Robotic End Effector Overload Protection Device

       Disclosed is an overload protection device for a robotic
end-effector (end-of-arm tool).

      The purpose of an overload protection device for a robotic end-
effector is to minimize or eliminate damage to the robotic
end-effector and minimize or eliminate damage to objects within the
work envelope of the robot in the event that the robot moves the end
effector to coordinates or along a trajectory which was not intended,
causing the end-effector to collide with another object.

      In a normal operating mode, a robotic arm moves the
end-effector between pre-defined coordinates along pre-defined
trajectories.  In the event that the robot loses its bearings, an
object is placed in the working envelope which is not expected or the
robot is directed to a coordinate in error, some means must be
provided to sense an overload condition, provide compliance between
the end-effector and the rigid interfering object and stop or reverse
the robot motion.

      For a description of the design and operation of the device,
please refer to the figure.

      The assembly is comprised of two plates 1 and 2.  Plate 2 is
attached to the end of the robot arm 3.

      Plate 2 has at least three sides.  Near the apex of any two
sides is a tapered pin 4 whose axes are parallel to the axis of the
robot end-of-arm (parallel to the X axis).  The pins are permanently
fixed (e.g., pressed) into the plate 2. Each pin engages a hole 10 in
plate 1.  The taper is positioned axially such that the diameter of
the pin 4 is the same as or slightly less than the diameter of the
holes 10 in the plane where the front face (+X) of plate 2 and the
rear face (-X) of plate 1 contact (e.g., the pins are a slip fit into
the holes at this interface).

      The rear face (-X) of plate 1 is held in contact with the front
face of plate 2 by a compression spring 9 held to plate 2 by screw
8 and washer 7.  Screw 8 passes through a central hole in plate 1 and
is threaded into a h...