Abstract: A clutch control system for the front wheel drive clutch of a four-wheel drive vehicle engages the front wheel drive clutch as a function of three brake-operated switches, a pair of manually-operated "OFF-ON-AUTO" mode switches and a pair of speed responsive switches connected between a battery and the solenoid of a front wheel drive clutch control valve. The system engages the clutch when vehicle speed is above a limit speed and both service brakes are applied even when the mode switches are in their "OFF" position wherein the clutch is normally disengaged.

Abstract: A clutch control system for the front wheel drive clutch of a four-wheel drive vehicle engages the front wheel drive clutch when both service brakes are simultaneously released or simultaneously applied, but disengages the clutch when only the left or the right service brake alone is applied. The control system includes three brake-operated switches, a manually-operated switch and a speed responsive switch connected to the solenoid of a front wheel drive clutch control valve.

Abstract: A quick coupler latch mechanism includes a latch pivoted on a quick coupler frame above a hook having a recess. A guide pin extends horizontally through the frame and is supported by thickened frame parts to resist bending deformation of the guide pin. An operator-controlled lever device moves a control bar within the frame. A guide member is rigidly fixed for movement with the lower end of the control bar and has a recess which slidably receives the guide pin. The guide member operatively engages the latch to pivot it between open and closed positions.

Abstract: A draft control system of the type in which a mechanical spring is employed to balance the draft forces of an implement trailed behind the tractor so as to correct the working depth of the implement in accordance with changes in draft forces, in which the feature is the use of a hydraulic force-amplifying device to increase the responsiveness of the system so as to minimize the forces required to effectuate regulation of the working depth of the implement.