TRACTOR TRIVIA and other interesting stuff 5/2/2024

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Power Take-Off (PTO)

 

During the early days of agricultural mechanization, the rotation of an implement’s wheels transferred rotational force to the mechanism to power a cutting blade, planter mechanism, hay elevator, side delivery rake, or thrasher. If soil conditions were unfavorable the machine wouldn’t work very well, if the ground speed of the animals pulling the device changed the effectiveness of the implement was reduced. It was still better than performing these operations by hand but there was room for improvement.

As tractors became more plentiful many stationary implements that had been powered by separate engines could now be operated with the flat belt pulley on the tractor. With the greater power and versatility offered by a tractor more backbreaking tasks were mechanized. Grain thrashers, hay presses, silage cutters and blowers could all be made larger and more efficient because of higher powered tractors driving them.

However, the field work continued to be done with the same ground driven implements that had been pulled by horses. There was no practical way to harness the engine’s power to improve the efficiency of these implements.

The first commercially successful power take-off (PTO) shaft attachment in the U.S. was made available for the International Harvester Corporation, IHC 8-16 in 1919. Now there was a third way to transmit tractor power. International Harvester emphasized this by advertising its later 10-20 and 15-30 models as “triple-power tractors. This new feature provided a competitive advantage for IHC but it was short-lived because soon other tractor manufacturers offered PTOs. Driven by the tractor engine the PTO powered implements, rather than being power by a rolling wheel which ceased transmission if the vehicle stops traveling, and the workload's resistance tends to make the wheel skid rather than turn, even if cleated. The concept of a shaft drive with easily connected and disconnected couplings, and flexibility for driving at changing angles (such as when an articulated tractor-and-trailer combination turns), was a wonderful advancement.