U.S. Patent Specifications Available to Purchase

A measuring and indicating instrument comprising means responsive to changes in the magnitude of the quantity being measured, indicating means comprising a disc having a radial slot therein, a screw‐threaded guide having a shaft coaxial with said disc, a helix mounted upon said shaft adjacent said disc, and means connecting said change responsive means to said shaft for actuating said helix to move it through the radial slot in said disc to form an indicating area which increases or decreases in size in proportion to an increase or decrease of the quantity being measured.