The drawbar was a flat bar with holes in it, and the implements were trailers, with tongues that attached to the drawbar with a pin through a hole. * refers to implement end tractor end not specified Historyīefore the 1940s, most hitching of farm implements to tractors was done simply with a drawbar, on the same principle as a modern tow hitch. The higher category hitches have sturdier lift arms and larger connector pins. There are five different hitch sizes, called categories. The draft of the implement, the amount of force it is taking to pull the implement, is sensed on the lower arms and the hydraulic system automatically raises the arms slightly when the draft increases and lowers the arms when the draft decreases. A draft control mechanism is often present in modern three-point hitch systems. The hydraulic system is controlled by the operator, and usually a variety of settings are available. The hitch lifting arms are powered by the tractor's own hydraulic system. The implement is secured by placing a pin on the ends of the posts. Each arm has an attachment device to connect implements to the hitch.Įach hitch has attachment holes for attaching implements, and the implement has posts that fit through the holes. The upper center arm-called the top link-is movable, but is usually not powered by the tractor's hydraulic system. The two lower arms-the hitch lifting arms-are controlled by the hydraulic system, and provide lifting, lowering, and even tilting to the arms. Three-point hitches are composed of three movable arms. These include the tractor's hydraulic system, attaching points, the lifting arms, and stabilizers. The three-point hitch is made up of several components working together. The hitch's utility and simplicity have since made it an industry standard. At 2,500 pounds (1,100 kg), the 9N could plow more than 12 acres (5 hectares) in a normal day pulling two 14-inch (360 mm) plows, outperforming the tractive performance of the heavier and more expensive Farmall F-30 model. For example, when the Ford 9N introduced Harry Ferguson's three-point hitch design to American production-model tractors in 1939, it was a light and affordable tractor competing principally with row-crop tractors such as Farmalls that did not yet have three-point hitches. This gives the tractor more usable traction than it would otherwise have, given the same power, weight, and fuel consumption. The primary benefit of the three-point hitch system is to transfer the weight and resistance of an implement to the drive wheels of the tractor. Three-point attachment is the simplest and the only statically determinate way of joining two bodies in engineering. The three points resemble either a triangle, or the letter A. The three-point hitch ( British English: three-point linkage) is a widely used type of hitch for attaching ploughs and other implements to an agricultural or industrial tractor. At 2,500 pounds (1,100 kg), the 9N could plow more than 12 acres (5 hectares) in a normal day pulling two 14-inch (360 mm) plows, outperforming the tractive performance of the heavier and more expensive Farmall F-30 model. The other main mechanism for attaching a load is through a drawbar, a single point, pivoting attachment where the implement or trailer is not in a fixed position with respect to the tractor. The tractor carries some or all of the weight of the implement. Three-point attachment is the simplest and the only statically determinate way of joining two bodies in engineering.Ī three-point hitch attaches the implement to the tractor so that the orientation of the implement is fixed with respect to the tractor and the arm position of the hitch. The three-point hitch (British English: three-point linkage) is a widely used type of hitch for attaching ploughs and other implements to an agricultural or industrial tractor.
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