Browse Prior Art Database

Variable Sensitivity Mechanical Sensor

IP.com Disclosure Number: IPCOM000084348D
Original Publication Date: 1975-Oct-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 3 page(s) / 40K

Publishing Venue

IBM

Related People

Folchi, GA: AUTHOR [+3]

Abstract

Described is a family of sensing wands or antennae with an overall nonlinear response. Such devices are particularly useful in mechanical manipulators which require a high resolution in the lower force range, a large force range, and damage resistance.

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Variable Sensitivity Mechanical Sensor

Described is a family of sensing wands or antennae with an overall nonlinear response. Such devices are particularly useful in mechanical manipulators which require a high resolution in the lower force range, a large force range, and damage resistance.

If a mechanical manipulator is used as a curve follower, the sensor must have a delicate touch in the low-force range. At the other extreme, if the manipulator is to be used to insert a shaft in a force fit, it must be capable of withstanding and measuring sizable forces.

The family of sensors all exploit the principle of a succession of resilient members which are sequentially activated to change the slope of the force displacement curve, to provide a series of "knees" with intervening linear relationships.

The drawing best illustrates the principle of the apparatus. The force sensing member 10, which may be one of the fingers of the gripper or the mount for the sensing wand, or both, is, in effect, a cantilever beam mounted via a flexible web 11 to a rigid frame member 12. Strain gauges 13 are affixed to the web 11 to measure its flexure as the beam 10 is deflected. The beam 10 is provided with an abutment or block 14, spaced from which are a pair of Vliers spring plungers 15 and 16 to provide clearance or backlash. The backlash is adjusted by screws 17 and 18 threaded in the holes in which the spring plungers 15 and 16 are seated.

Initially, as the beam 10 is deflected, the force displacement curve is a function of the flexure of the web 11 and is represented by the linear portion from A to B. As the displacemen...