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CVTs/IVTs FORUM
THOMAS TRANSMISSION
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THOMAS TRANSMISSION
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AP AUTOMATIC GEARBOX

   Thomas transmission is an integral part of an automo­bile engine whose piston motion is transferred by a conventional connecting rod to the long arm of the bellcrank lever oscillating about a fixed fulcrum. A horizontal connecting rod, which rotates the crank­shaft, is attached to the short arm of the bellcrank. Crankshaft motion is steadily and continuously maintained by a flywheel. However, no power other than that required to drive auxiliaries is taken from this shaft.

 

   The main power output is transferred from the bellcrank lever to the over-running clutch by a third connecting rod. The speed ratio is changed by sliding the top end of the third connecting rod within the bellcrank lever with a crosshead and guide mechanism. The highest ratio is obtained when the crosshead is farthest from the fulcrum, and movement of the crosshead toward the fulcrum reduces the ratio until a "neutral" position is reached. That occurs when the center line of the connecting rod coincides with the fulcrum.

thomasdrive.jpg
Thomas Transmission

Source :

 

Mechanism and Mechanical Devices Sourcebook. Second edition, 1996. Author : Nicholas P Chironis & Neil Sclater. Published by McGraw-Hill, New York, USA.