US 5,174,115 AGranted

Electrically actuated and controlled auxiliary hydraulic system for skid steer loader

AssigneeClark Equipment Company

InventorsScott B. Jacobson, Kenneth A. Brandt

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Abstract

The present invention relates to an electrically actuated and controlled auxiliary hydraulic system for controlling the flow of hydraulic fluid under pressure to mounted attachments on a skid steer loader. In one embodiment, an electrically actuated auxiliary control valve is coupled to the front and rear mounted attachments through an electrically actuated diverter valve. In a second embodiment, a front and a rear auxiliary control valve is coupled to the front and rear mounted attachments. An operator can select between control of either the front or rear attachments by selectively actuating the forward, reverse and latch switches on the control handles. A mode control switch electrically coupled to an auxiliary mode control circuit allows the cyclical selection between the disable mode, the momentary mode, and the latch mode. In the disable mode, the actuation of the forward, reverse or latch switches has no effect. In the momentary mode, the operator controls the particular attachment during the time of the switch actuation. In the latch mode, the front attachment can be operated in a high pressure mode allowing extra power to be delivered to the front attachment.

Claims24

Dependent claims

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

an operator compartment;
an engine;
a hydraulic pump driven by the engine for providing hydraulic fluid under pressure;
a lift arm assembly;
a forward attachment mount for removably mounting said attachment having an auxiliary hydraulic motor to the lift arm assembly;
a first auxiliary fluid fitting for coupling the hydraulic fluid to the hydraulic motor of the attachment;
an electrically actuated auxiliary control valve coupled in a hydraulic circuit between the hydraulic pump and the first auxiliary fluid fitting for controlling hydraulic fluid flow in response to electric auxiliary control signals;
a momentary auxiliary control switch system including a forward momentary switch coupled to the electrically actuated auxiliary control valve for causing momentary hydraulic fluid flow in a forward direction during actuation of the forward momentary switch by an operator;
a latching auxiliary control switch system including a latch switch coupled to the electrically actuated auxiliary control valve for causing continuous fluid flow in a forward direction in response to operator actuation of the latch switch;
an auxiliary enable switch having ON and OFF positions;
and
an auxiliary mode control circuit coupled to an auxiliary enable switch, an auxiliary mode control switch, the momentary auxiliary control switch system, the latching auxiliary control switch system and the electrically actuated auxiliary control valve, for operating in a disable mode, wherein the momentary switch system and latching switch system are disabled when the enable switch is actuated from the OFF position to the ON position, for operating in a momentary mode in response to operator actuation of the mode control switch when the enable switch is in the ON position thereby enabling momentary switch control over the electrically actuated control valve and disabling latch switch control over the electrical actuated control valve, and for operating in a latch mode in response to a next subsequent operator actuation of the mode control switch when the enable switch is in the ON position thereby enabling latch switch control over the electrically actuated auxiliary valve.

9 more elements

An electrically controlled auxiliary hydraulic system coupled to an apparatus having a hydraulic pump, an electrically actuated auxiliary control valve and a plurality of auxiliary hydraulic fittings, including front auxiliary fluid fittings and rear auxiliary fluid fittings, the electrically controlled auxiliary hydraulic system including:

an electrically actuated auxiliary control valve coupled in a hydraulic circuit between the hydraulic pump and the front auxiliary fluid fitting for controlling hydraulic fluid flow in response to electric auxiliary control signals;
a momentary auxiliary control switch system including a forward momentary switch coupled to the electrically actuated auxiliary control valve for causing momentary hydraulic fluid flow in a forward direction during actuation of the forward momentary control switch by an operator;
a latching auxiliary control switch system including a latch switch coupled to the electrically actuated auxiliary control valve for causing continuous fluid flow in a forward direction in response to operator actuation of the latch switch;
an auxiliary enable switch having ON and OFF positions;
and
an auxiliary mode control circuit coupled to the auxiliary enable switch, an auxiliary mode control switch, the momentary auxiliary control switch system, the latching auxiliary control switch system and the electrically actuated auxiliary control valve, for operating in:
a disable mode thereby disabling control over the electrically actuated auxiliary valve by the momentary switch system and latching switch system when the enable switch is actuated from the OFF position to the ON position;
a momentary mode thereby enabling momentary switch control over the electrically actuated control valve and disabling latch switch control over the electrical actuated control valve in response to operator actuation of the mode control switch when the enable switch is in the ON position;
a latch mode thereby enabling latch switch control over the electrically actuated auxiliary valve in response to operator actuation of the mode control switch when the enable switch is in the ON position.

6 more elements

Dependencies are inferred from the claim text.