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Marchant Figurematic - Technical Description


Marchant10DRX.jpg (9kb) These pages give an illustrated technical description of the internal mechanism and the principles of operation of the Marchant "Figurematic" mechanical calculator.

The machines built by the Marchant Calculator Company during its sixty-year history can be divided into three broad families, according to the design of their internal mechanism:

The notes and photographs in these pages are based on a Marchant "Figurematic" Model 10DRX from the 1950s. They were prepared during the overhaul of machine number 412562 during 2004. The descriptions are based primarily on my own observations and interpretations, supplemented by reference to reprints of Marchant drawings and training materials. A subsequent review of Marchant patent information has clarified some of the subtleties of the mechanism, but has not required any major alterations to the text.

These notes are intended as a general guide to the construction and the principles of operation of the Figurematic mechanism. They do not attempt to explain all of the internal details, nor do they provide detailed instructions for disassembly or repair. While I believe my descriptions to be substantially correct, I do not guarantee that they are accurate, complete, or applicable to any other machine. Please do not dismantle a Marchant in the expectation that these notes alone will get it back together!

I would welcome advice of any corrections, or suggestions for improvement.



Contents

  1. Introduction (this page)
  2. Overview
  3. The keyboard
  4. The actuator unit
  5. The selector unit
  6. The control unit
  7. The drive train
  8. The multiplier
  9. The carriage
  10. The counter register
  11. The main register and carry mechanism
  12. The carriage shift mechanism
  13. The clearing mechanism
  14. The division control mechanism
  15. Description of operation
  16. Marchant patents

Resources for Further Information

MarchantLogo2.jpg (9kb)


Original text and images Copyright © John Wolff 2005-15.
Use at own risk; beware of errors; suggestions for improvement welcome.
Last Updated: 29 July 2015

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