Microcalipers with calculator-assisted display

Claim 1

An improvement in micro-calipers comprising: a main beam; a mount slidably mounted on said main beam; gage means carried by said mount; a rack bar fixedly mounted on the main beam and having a toothed marginal portion; said gage means comprising: a pinion rotatably mounted on said mount and engaged with said rack bar; a first disc mounted coaxially with said pinion on said mount and having a plurality of electrically conducting, and concentrically disposed circumferentially spaced projections; the spacing between said projections corresponding to a predetermined displacement length of said mount with respect to said main beam; an electrically conducting pointer disposed in a plane above said projections for contact therewith; an insulating disc supporting said first disc on said mount, a shaft extending coaxially through said discs, said shaft being electrically conductive and connected to said pointer and said pinion in coupled driving relation such that the pointer undergoes rotation about the center of said projections in said plane on said projections; a first lead in sliding electrical contact with said shaft; and a second lead in electrical contact with said projections; conductivity being established between said leads upon said pointer being in electrical contact with one of said projections, said first and second leads being attachable to first and second contacts, respectively, of a calculator result-key such that a predetermined longitudinal displacement of said mount with respect to said main beam from a first position to a second position results in rotation of said pointer above said projections and production of a predetermined number of conductivity pulses between said leads, said calculator cumulating said pulses and including a display means for providing visual read out of the cumulated pulses and means for adding and subtracting pulses according to the direction of movement of the mount on the main beam.