Three-point Hitch Research Articles

A Device for Controlling the Feedrate of Subsurface Trickle Irrigation Tubing

A three-point hitch, mounted implement was developed to control the rate at which bi-wall trickle irrigation tubing was inserted into the soil. A doppler radar velocity sensor measured ground speed and provided an input signal to a single board computer. The computer used an error feedback loop to generate an output signal which operated a throttling valve, controlling flow to a hydraulic motor coupled to one of two metering wheels. The wheels, mounted on parallel shafts with their faces in contact, utilized friction to pull tubing from the supply roll and feed it into a duct leading down behind a subsoiler shank and into the soil. Field tests showed that the implement operated satisfactorily over the range of 3.7 to 5.6 km/h (2.2 to 3.3 mile/h). Average deviation in metering wheel peripheral speed compared to travel speed was 1.4%.

DEVELOPMENT OF A WHOLE-STALK SWEET SORGHUM HARVESTER

ABSTRACT Sweet sorghum can be readily grown in the Eastern U.S. Piedmont, but irregular-shaped fields on rolling terrain present a challenge to mechanical harvesting. An Atkinson sugarcane harvester was converted from a three-point hitch to a pull-type machine. Gathering chains captured the stalks as they were cut at the base, and elevated them at a 30 angle. The stalk was gripped between two rotating disks and flipped to the horizontal position. Disk tangential velocity was 24% greater than chain velocity. Total power required was 33 kW (44 hp) with 67% for the chains and 28% for drawbar pull.

Multi-Purpose, Vegetable Production Machine Investigations

Two multi-purpose, vegetable production vehicles with 3-m (10-ft) spans have been developed by retrofitting commercial high-clearance power units. Bi-directional and movable operator stations were designed to allow the operator to view critical field operations. Dual three-point hitch systems were incorporated into the design to allow multiple field operations in a single pass. The prototype vehicles have successfully performed tillage, bed shaping, planting, cultivating, spraying, and harvesting operations.

Dinamometriade implementos montados: uma solução simplificada

Desenvolveu-se e testou-se um conjunto torre-braços articulados para engate ao sistema de levante hidráulico de implementos montados com apoio sobre rodas, mais especificamente unidades semeadoras-adubadoras de linhas múltiplas, para a determinação de suas exigências de tração. Como elemento sensor, usou-se um anel simples para tração/compressão, instruments do a extensômetros elétricos em ponte completa, conectado por cabos de aço flexíveis entre a barra do implemento e a base da torre intermediária. Projetado para trabalhos na faixa de 0-6.000N, submetido a testes de calibração estática, mostrou alta linearidade de resposta com R = 0,9997, um excelente retorno ao zero e resolução em torno de 70N. O conjunto, levado a testes com uma unidade semeadora-adubadora de sete linhas, em terreno firme, plano e inclinado, acusou esforços altamente consistentes com valores resultantes de cálculos simples; isso, aliado à simplicidade de sua concepção, confere-lhe um caráter de alta confiabilidade. O uso do conjunto altera a geometria trator-implemento, o que não constitui problema maior quando se está interessado em esforços de fração apenas, em se tratando desse tipo de implemento. Valores obtidos em trabalhos em terreno plano e preparado para plantio, bastante discrepantes dos encontrados em literatura, mostram a conveniência da execução de trabalhos sistemáticos para o conhecimento das reais necessidades de tração desses implementos em nossas condições.

A theory for the influence of the hitch on lateral displacement of implements

The lateral behaviour of implements returning from a lateral deflection, operating on a hillside and operating with an asymmetric centre of resistance is analysed. The analysis is limited to implements whose lateral motion is heavily overdamped. Special attention is paid to the influence of the type of hitch used. The implement is found to return exponentially from a lateral disturbance. The disturbance is reduced to 10% of its initial value when the implement has moved forward a distance of 2·3 times the length of the hitch. The lateral deflection and the angular deflection of an implement when operating on a hillside or when subjected to an asymmetrical centre of resistance is analysed. The properties of the three-point hitch are found to be unique when compared to the properties of the single-point hitch. It is found possible to construct laterally movable front-mounted three-point hitches that centre directional as well as non-directional implements. The construction and successful test of such a hitch is reported.

An Implement for Extracting Subsurface Irrigation Laterals

Athree point hitch mounted implement was developed to extract and collect subsurface trickle irrigation laterals from the soil. Power to the implement was supplied from the tractor through the three-point hitch and two remote hydraulic circuits. In operation, the implement loosened the soil around the lateral, extracted the lateral from the soil and wound it onto a reel. The roll of tubing then was dropped at the end of the row. Draft power averaged 14.5 kW (19.4 hp) and hydraulic power averaged 0.6 kW (0.8 hp) when the one row implement was operated at 7.2 km/h (4.5 mph). Field capacity of the one row implement was 0.19 ha/h (0.47 ac/h) when operated in a field having 100 m (328 ft) long rows on 100 cm (40 in.) centers.

A Single Cereal Spike, Thresher-Planter

Many cereal breeding programs use spike rows to advance generations. Thus, thousands of spikes are threshed, placed in coin envelopes, put in seed magazines, and eventually planted each year. A machine was designed and built that threshes and plants spikes in one operation. In row spacing between spikes can be varied from 18 to 24 in. The spike planter can be mounted on a small garden tractor with a three-point hitch. This machine will greatly reduce the time spent of threshing and planting of individual wheat (Triticum aestivum L.) or barley (Hordeum vulgare L.) spikes. The spike planter will reduce labor and other expenses connected with threshing and planting single spikes.

Three-Point Hitch Dynamometer Design and Calibration

A three-point hitch dynamometer was designed, constructed and calibrated. The dynamometer is suitable for use with tractors up to 90 kW using category II and III mounted implements, and also trailed implements. A hydraulic clamp was used to absorb shock loads while equipment was being transported and lifted. Calibration of the dynamometer shows that the instrument is accurate to within 5% for draft forces ranging from 5 kN to 45 kN in any direction.

4545456 Four-wheel drive axleshaft clutch mechanism : William R Lake assigned to Ford Motor Company

In the vertical longitudinal plane of a tractor, the three-point hitch system is a six-bar mechanism that can be designed and modelled as two distinct four-bar linkages sharing two links. A Newton–Raphson solution for the four-bar linkage has been applied to a three-point hitch system of tractor to determine the range of movement of the lift arm and generate the path of motion of lower and upper hitch points in the movement range of the hitch. The algorithm was executed as a program in MATLAB. The program has the ability to generate the path of motion of lower; upper and virtual hitch points, determine the geometric performance parameters of the hitch system, and identify the variations in the quality of force transmission by the linkage system throughout the range of hitch movements for 165 different groups of hitch dimensions available in the Nebraska tractor test reports. Application of the program for searching improved design solutions for the existing hitch system of a tractor was demonstrated. The program has the potential to be used in any search-based techniques for optimisation of the dimensions of three-point hitch systems for tractors. In addition, variations in length of links and spatial location of their pivot points were studied for various categories of hitches. The range of values of link lengths and the spatial location of their pivot points reported here can be used for defining the design space during the optimal dimensional synthesis of tractor three-point hitch systems.

4544174 Driving mechanism for vehicle propelled by human muscle power : Jecheskel Davidovitch, Ramath Gan, Israel

In the vertical longitudinal plane of a tractor, the three-point hitch system is a six-bar mechanism that can be designed and modelled as two distinct four-bar linkages sharing two links. A Newton–Raphson solution for the four-bar linkage has been applied to a three-point hitch system of tractor to determine the range of movement of the lift arm and generate the path of motion of lower and upper hitch points in the movement range of the hitch. The algorithm was executed as a program in MATLAB. The program has the ability to generate the path of motion of lower; upper and virtual hitch points, determine the geometric performance parameters of the hitch system, and identify the variations in the quality of force transmission by the linkage system throughout the range of hitch movements for 165 different groups of hitch dimensions available in the Nebraska tractor test reports. Application of the program for searching improved design solutions for the existing hitch system of a tractor was demonstrated. The program has the potential to be used in any search-based techniques for optimisation of the dimensions of three-point hitch systems for tractors. In addition, variations in length of links and spatial location of their pivot points were studied for various categories of hitches. The range of values of link lengths and the spatial location of their pivot points reported here can be used for defining the design space during the optimal dimensional synthesis of tractor three-point hitch systems.

Speed Control for Hydraulically Powered Outboard Wheel

AN outboard wheel was used to support a harvesting machine attached by means of the three-point hitch to the right side of a small (approximately 20 kW) tractor. The wheel was hydraulically powered to alleviate side draft caused by the rolling resistance of the wheel, and the draft from a trailer which was hitched, offset to the tractor directly behind the harvester to receive the harvested material. The wheel support frame was pivoted on a vertical axis which allowed the frame to move back and forth between stop blocks. This motion was used to modulate a value which controlled the flow of hydraulic oil to the wheel drive motor. If the wheel moved too far ahead, it would partially close the valve and bring the wheel back to its proper position. The control system worked properly in controlling wheel speed and eliminated side draft up and down slopes, on level ground and in left- and right-hand turns.

A Force Dynamometer for Three-Point Hitches

ABSTRACT A three-point hitch accessory was designed and constructed to measure draft, vertical force, and torque simultaneously and independently in a vertical longitudinal plane caused by an implement. Special features of the force dynamometer are dual-loading range and fast-hitching capability. The force dynamometer is designed for tractors in the 75- to 100 kW power range with maximum draft capacity of 66,700 N in the dynamometer's high-range and 36,000 N in the low-range.

A CROP HARVESTER FOR FORAGE PLOTS

The small crop harvester described is designed to cut yield samples from forage experimental plots. The machine, based on the principle of a flail type forage harvester, is mounted on a standard 2-plough tractor by a conventional three-point hitch and the rotor mechanism is driven from the tractor power take-off shaft. The unit cuts a swath 35 inches wide. The chopped forage material is delivered directly to an attached collection box which has a capacity for 80 lb. of green chopped material and can be unloaded from the rear. This device operates efficiently on grass or legume crops of any density with a height up to 30 inches and it chops the material into suitable lengths for sampling purposes.