Tractor . A tractor (from the Latin tractus , from trahĕre , to drag) is any machine that produces traction. They are self-propelled equipment to which different machines and implements are added by suspension, drag, push, or for remote operation. The most common are those used in agriculture to add machines, implements and trailers. They are also used in construction works, generally with accessories such as push shovels, loaders, backhoes, etc. Walking tractors are small tractors, which are generally operated by a pedestrian operator.
Generalities
All living beings have always needed to perform various mechanical tasks that involve pulling, pushing, etc., using their hands and other parts of the body for their survival. With the emergence of agriculture, these tasks became increasingly complex and required greater energy. An enormous advance was the beginning of the use of animal traction , which was used for centuries, but the increase in population required new, more advanced and productive technologies.
The invention of the steam engine led to the emergence of the first mechanical tractors at the end of the 19th century. Initially, they were stationary machines that moved the plough by means of a cable, although they soon became self-propelled. After 1900, tractors with gasoline engines became more widespread . In 1922, the diesel engine was introduced , a fuel that was cheaper. Recently, electric tractors have emerged.
Main mechanisms of the tractor
Chassis . It consists of a structure that provides rigidity and supports the other components of the equipment.
Energy system . It consists of the engine , the battery and the electrical system.
Mechanical transmission . The transmission system is the set of mechanisms that have the function of transmitting the mechanical energy produced by the engine to the other driven components. It includes the gearbox, differential, clutch, final drive, running gear and power take-off.
Running system . Although tyred tractors predominate, the running system on mats (tracks) is used to ensure greater grip on the ground and to reduce the specific load on the ground. Wheeled tractors are classified with two numbers, the first indicates the total number of wheels and the second how many of them are driving: 2×2, 3×2, 4×2, 4×4, 6×4, 6×6.
Power take-off . It is a shaft (axle) with rotary movement driven by the tractor engine , intended to transmit rotational power to machines or implements. It is generally known as the power take-off shaft (PTO) .
Hydraulic system . An engine-driven pump compresses hydraulic oil, which is transmitted through tubes and hoses to the cylinder that operates the implement lifting system, brakes and steering. Quick-release valves are available to operate the attached machines or implements.
Hitch system . The three-point hitch (or lifting) system is the mechanism that tractors have to hook implements and other machines for towing or suspension.
Steering . This is the set of organs that allow the trajectory to be modified in order to follow a new course. The fundamental components of mechanical steering are: steering wheel, steering shaft or column, universal joint, gearbox or worm screw, connecting rod and coupling rods. Another variant is steering actuated by a hydraulic piston.
Rankings
There are many ways to classify tractors: according to their intended use, according to the type of wheel drive, according to the power delivered by the PTO shaft, according to the engine power, according to the tractive force, etc. See the article Classification of tractors .
Safety rules
The tractor causes most fatal accidents in the agricultural sector due to crushing, running over or entrapment. These accidents occur both by the tractor itself and by the machines and implements attached to it. The main safety rules are as follows: The tractor must have a protective structure or cabin to protect the operator in the event of a rollover. Additional passengers are not permitted except in cases where an operator instructor is required, in which case an additional seat will be provided. Uninvolved persons are not permitted in the vicinity of the tractor when it is in operation. It is not permitted to get on or off the tractor or the attached equipment when they are in operation. Access to the mechanisms is not permitted when they are in motion. Tractor operators must be suitably qualified.