Wage calculations with lookup table on a cylinderĬircular adding disk on threaded shaft position on shaft indicates hundreds Interest calculator using lookup tables printed on polygonal cylinders Sliding bars with replaceable cards for computing tax or interestĬircular adding wheel with numbers in a spiralĪddometer with sliding guides to facilitate reading numbers from ledgerĭisk adding machine with improved carry mechanismĭisk adding machine with levers to move disks, and display drums for addition and subtraction resultsĪddometer with half-circle slots, and slide counter to assist with multiplication Lookup table imprinted on drum placed inside common octangular board rule or measure used with lumbermen Sum indicated on a single racheted rod, key movement restricted to number of notches for value Table imprinted on drum with slotted sleeve for viewing results Calculator Patents - Mechanical (non-Comptometer) ![]() No copyright claim is made to original U.S. ![]() This compilation Copyright (C) 2005 Mike Sebastian.
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