Electrically controlled auxiliary hydraulic system for a skid steer loader

A skid steer loader adapted for use in conjunction with an attachment having a hydraulic motor, including:

• an operator compartment;
• an engine;
• ground engaging drive wheels;
• hydraulic pump means driven by the engine for providing hydraulic fluid under pressure;
• an attachment mount for mounting an attachment having a hydraulic motor to the loader;
• auxiliary fluid fitting means for coupling hydraulic fluid to a hydraulic motor of an attachment;
• a hydraulic control valve coupling the auxiliary fluid fitting means to the hydraulic pump means in a hydraulic circuit, for controlling hydraulic fluid flow to the auxiliary fluid fitting means;
• an electrically actuated pressure relief assembly coupled in the hydraulic circuit and responsive to electric pressure control signals for causing the pressure of the hydraulic fluid to have one of a plurality of maximum pressures;
• and
• a pressure control switch mounted within the operator compartment and coupled to the pressure relief assembly, for controlling the electric pressure control signals in response to operator actuation, thereby permitting the operator to select the maximum pressure of the hydraulic fluid in the hydraulic circuit.

A skid steer loader adapted for use in conjunction with front and/or rear mounted attachments having hydraulic motors, including:

• an operator compartment;
• an engine;
• ground engaging drive wheels;
• hydraulic pump means driven by the engine for providing hydraulic fluid under pressure;
• a lift arm assembly pivotally mounted to the loader;
• a front attachment mount for removably mounting a front mounted attachment having a hydraulic motor to the lift arm assembly;
• front auxiliary fluid fitting means for coupling hydraulic fluid to a hydraulic motor of a front mounted attachment;
• a rear attachment mount for removably mounting a rear mounted attachment having a hydraulic motor to a rear portion of the loader;
• rear auxiliary fluid fitting means for coupling hydraulic fluid to a hydraulic motor of a rear mounted attachment;
• an auxiliary control valve fluidly coupled between the hydraulic pump means and the front and rear auxiliary fluid fitting means;
• an electrically controlled diverter valve fluidly coupled between the auxiliary control valve and the front auxiliary fluid fitting means, and between the auxiliary control valve and the rear auxiliary fluid fitting means, for selectively routing hydraulic fluid between the auxiliary control valve and one of the front and rear auxiliary fluid fitting means in response to electric auxiliary select control signals;
• and
• a diverter switch mounted within the operator compartment and coupled to the diverter valve for controlling the auxiliary select signals in response to operator actuation.

A skid steer loader adapted for use in conjunction with front and/or rear mounted attachments having hydraulic motors, including:

• an operator compartment;
• an engine;
• ground-engaging drive wheels;
• hydraulic pump means driven by the engine for providing hydraulic fluid under pressure;
• a lift arm assembly pivotally mounted to the loader;
• a front attachment mount for removably mounting a front mounted attachment to the lift arm assembly;
• front auxiliary fluid fitting means for coupling hydraulic fluid to a hydraulic motor of a front mounted attachment;
• a rear attachment mount for removably mounting a rear mounted attachment to the rear of the loader;
• rear auxiliary fluid fitting means for coupling hydraulic fluid to a hydraulic motor of a rear mounted attachment;
• an electrically actuated auxiliary control valve coupled in a hydraulic circuit between the hydraulic pump means and the front and rear auxiliary fluid fitting means, for controlling hydraulic fluid flow in response to electric auxiliary control signals;
• an electrically controlled diverter valve coupled in the hydraulic circuit between the auxiliary control valve and the front auxiliary fluid fitting means, and between the auxiliary control valve and the rear auxiliary fluid fitting means, for selectively routing hydraulic fluid between the auxiliary control valve and one of the front and rear auxiliary fluid fitting means in response to electric auxiliary select signals;
• an electrically actuated pressure relief assembly coupled in the hydraulic circuit and responsive to electric system pressure control signals for causing pressure of the hydraulic fluid in the hydraulic circuit to have one of a plurality of maximum pressures;
• a diverter switch mounted within the operator compartment and coupled to the diverter valve for controlling the auxiliary select signals in response to operator actuation;
• an auxiliary control switch mechanism mounted within the operator compartment and coupled to the auxiliary control valve, for permitting operator control of the electrically actuated auxiliary control valve by controlling the electric auxiliary control signals in response to operator actuation;
• and
• a pressure control switch mounted within the operator compartment and coupled to the pressure relief assembly for controlling the electric system pressure control signals in response to operator actuation, thereby permitting the operator to select the maximum pressure of the hydraulic fluid in the hydraulic circuit.

A skid steer loader adapted for use in conjunction with an attachment having a hydraulic motor, including:

• an operator compartment;
• an engine;
• ground-engaging drive wheels;
• hydraulic pump means driven by the engine for providing hydraulic fluid under pressure;
• an attachment mount for removably mounting an attachment having an auxiliary hydraulic motor to the loader;
• auxiliary fluid fitting means for coupling hydraulic fluid to a hydraulic motor of an attachment;
• an electrically actuated auxiliary control valve coupled in a hydraulic circuit between the hydraulic pump means and the auxiliary fluid fitting means, for controlling hydraulic fluid flow in response to electric auxiliary control signals;
• an electrically actuated pressure relief assembly coupled in the hydraulic circuit for selectively relieving pressure in the hydraulic circuit at a first relatively low relief pressure or a second relatively high relief pressure in response to electric system pressure control signals;
• an auxiliary latch switch assembly mounted within the operator compartment and coupled to the auxiliary control valve and to the pressure relief assembly, for controlling auxiliary control signals causing continuous fluid flow in a first direction to the auxiliary fluid fitting means, and for controlling pressure control signals actuating the pressure relief assembly to select the second relatively high relief pressure in the hydraulic circuit, when actuated by an operator.