Browse Prior Art Database

Thickness Sensing Gage

IP.com Disclosure Number: IPCOM000108073D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Adams, EM: AUTHOR [+3]

Abstract

Described is a thickness sensing gage which is designed to sense the thickness of a stack of sheets to determine if the proper number of sheets in a stack are present. The gage is particularly applicable to the thickness sensing of ceramic green and mylar sheets as used in circuit board fabrication.

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Thickness Sensing Gage

       Described is a thickness sensing gage which is designed
to sense the thickness of a stack of sheets to determine if the
proper number of sheets in a stack are present.  The gage is
particularly applicable to the thickness sensing of ceramic green and
mylar sheets as used in circuit board fabrication.

      In prior art, Go/No-Go actuating switches have been used to
determine if the proper number of sheets were present in a stack.
However, with the close tolerances of ceramic sheets stacked with
mylar sheets, the automatic determination of the correct number of
sheets requires a gage with greater sensitivity.  The concept
described herein replaces the Go/No-Go actuating switch approach with
sensitive sensors which have a repeatability accuracy of .000040 in.

      The figure shows a front view of the thickness-sensing gage
with a stack of sheets in place ready for sensing. Spring-loaded
plunger 1 moves in precision guide bushing 2 which is mounted in
carriage bracket 3.  Carriage bracket 3 is mounted to the carriage of
ball slide 4.  Ball slide 4 is actuated by pneumatic cylinder 5.
When pneumatic cylinder 5 is extended, carriage bracket 3 moves down
until stop button 6 rests on the top surface of part carrier plate 9.
The top surface of part carrier plate 9 becomes the datum surface for
the thickness measurement, thereby eliminating the thickness
variability of part carrier plate 9 from consideration.

      As stop butto...