| 摘要 |
An articulated tractor in which there is a front first tractor vehicle and rear second and third tractor vehicles, each of the tractors having an engine for driving the wheels of the tractor and the first tractor having an operator's compartment, the second and third tractors being connected to the first tractor through a cross bar pivotally secured adjacent its longitudinal midpoint to the rear of the first tractor for pivotal movement both about a generally vertical axis and a generally horizontal axis. The rear second and third tractors are secured to the cross bar by pivotal connections at points equally spaced from the first pivotal means so that the longitudinal axis of the second and third tractors are normally substantially parallel to each other. The steering is accomplished by a steering control in the operator's compartment which changes the angular relationship about a vertical axis of the cross bar to the first tractor vehicle to cause the longitudinal axes of the second and third tractor vehicles to assume temporarily an angular relationship with the longitudinal axis of the first tractor vehicle. The pivotal connections of the second and third tractor vehicles to the cross bar are designed to permit pivotal movement of these vehicles with respect to the cross bar about their longitudinal axes. There is also a further cross bar pivotally connected to the second and third tractor vehicles at the rear thereof in such a manner as to allow turning of the tractor vehicles about their longitudinal axes with respect to the second cross bar. In addition to the two cross bars, there are pull rods extending between the cross bars so as to transmit pulling forces from the front cross bar to the rear cross bar. The implement to be pulled is coupled to the rear cross bar. There preferably are three cross bars, one in the center and one extending between the front and rear pivotal connections of the second and third tractors to the two cross bars. The cross bar is connected to a front tractor by means of a center yoke which is pivoted about a generally vertical axis to the front tractor vehicle and is pivoted about a generally horizontal axis to the cross bar.
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