What Is Pto on Tractor？

PTO, short for "Power Take-Off," was invented by Edward A. Johnston, the chief engineer of the International Harvester Company (IHC), and was first tested on a tractor around 1919. In 1921, it could be configured on the International 15-30 model tractor through special orders.

While PTO has become a standard feature on today's tractors, it faced many challenges when it was invented over 100 years ago. 

The tractor comes standard on the rear PTO

According to records, in 1905, a Frenchman named Albert Gougis built a tractor and connected the engine crankshaft to the shaft of a McCormick binder using a chain drive and several universal joints. This mechanical mechanism could be controlled separately by a clutch, allowing the tractor to tow and drive the binder. Gougis developed this equipment to help farmers harvest fallen grain and achieved success.

Around 1906, engineers from the International Harvester Company saw Gougis' device during their visit to France, which sparked the idea of using PTO on tractors.

In 1917, engineer Bert R. Benjamin proposed the development of a PTO device for the 10-20 model tractor. He mentioned that a farmer owned several binders, one 10-20 model tractor, one 8-horsepower tractor, and several horses. If a PTO was installed on the 10-20 model tractor, he could afford to buy more tractors to improve the efficiency of the binders. His proposal was approved, and PTO was developed to drive a machine called a power cultivator. Although this machine was not successful, the early engineering designs and experiments opened the door for the invention of the Farmall tractor.

A power cultivator

In 1919, the International Harvester Company conducted tests on its 8-16 model tractor. In 1921, it could be configured on the International 15-30 model tractor. The new products introduced in 1921, the 10-20 and 15-30 model tractors, could also be equipped with PTO. The Farmall tractor, introduced in 1922, was equipped with PTO and became a functional device on tractors.

PTO device for Model 8-16 tractor test machine

PTO became widely known in the industry in the late 1920s when PTO-driven implements played an active role in disaster relief for rice crops affected by rainfall in several states in the southern and central United States in 1925. Since then, PTO entered people's sight and became a standard feature on tractors.

Test motor driven PTO on Model 10-20 tractor

In the 1950s, the International Harvester Company released the HUNRED series tractors, which introduced new hydraulic devices, independent PTO (IPTO), and two-point hitch systems. The independent PTO could rotate even when the main clutch was disengaged and the tractor was stopped. In contrast, the previous PTO did not work when the main clutch was disengaged.

The power of the IPTO was directly provided by the engine without the need for the main clutch and transmission. This required additional housing and durable moving parts, but the benefits were evident.

In the 1950s, FARMALL tractors operated baling machines powered by PTO

The invention and application of the tractor PTO is a typical example of the ingenuity of agricultural engineers. It started with the creativity of machine users (farmers) and went through improvements, testing, and standardization by engineering teams in manufacturing companies to become mass-produced products. Due to its practicality, other companies in the industry followed suit and made it a standard feature. Subsequent technological advancements have made modern tractor PTOs more mature and versatile.