Patent application number | Description | Published |
20090139395 | HYDRAULIC SYSTEM WITH WARM UP CIRCUIT - A hydraulic control system in which a pump for pressurized hydraulic fluid connects with a valve assembly having a valve element displaceable in a chamber to selectively direct fluid to a load driven by the hydraulic system. Surfaces on the end faces of the valve element are exposed to hydraulic pressure from a controller via electro-hydraulic solenoid valves. The surfaces of the valve element adjacent the end faces are undercut to establish a leakage flow path and the solenoid valves are selectively actuated to pressurize the end faces to a level below normal actuation of the valve element but high enough to cause fluid to return to a drain and thus increase the temperature of the hydraulic fluid in the system. | 06-04-2009 |
20110132681 | Steering Control System Combining Electro-Hydraulic And Manually-Actuated Pilot Pressure Control Valves For Safe Operation - A steering control system for directing fluid to steering actuators on a machine include a set of right and left manually-operated pilot pressure fluid control valves and a set of right and left electro-hydraulic (EH) pilot pressure fluid control valves, with both sets being coupled to a main steering control valve for controlling movement of the latter to effect operation of the steering actuators. An electronic control unit (ECU) includes a computer and a memory and receives signals representative of various operating parameters of the control system and of the vehicle ground speed and operates to control the EH pilot pressure control valves and a set of right and left solenoid-operated valves such that only flow from the set of manually-operated valves is connected for operating the main steering control valve to effect a least aggressive steering mode when the vehicle speed is indicative of road travel, and for also actuating the EH pilot pressure control valves for effecting a more aggressive steering mode when the vehicle speed is low indicating off-road travel. EH valve failure results in the control system defaulting to that for effecting the least aggressive steering mode, while failure of one or both of the manually-controlled valves results in the EH control valves being activated to provide that pilot pressure called for by the manually-operated valve. | 06-09-2011 |
20120324874 | INDEPENDENT SUPPLY AND EXHAUST METERING WITHIN A VALVE CASTING - The present disclosure provides a hydraulic system for controlling a load. The system includes a housing defining an inlet, a first port, and a second port. The system further includes a spool valve and a proportional control element. The spool valve is in fluid communication with the inlet and the second port and the proportional control element is in fluid communication with the first port. The proportional control element can be controllable to exhaust fluid from the first port to a reservoir. In this arrangement, the proportional control element and the spool valve are controlled independently of one another. | 12-27-2012 |
20130168166 | Inverter Mounting on an Electric Drive Loader - The present disclosure provides a work machine having a frame and a front and rear wheel axle. The machine includes a cab coupled to the frame. The cab is configured to include controls for controlling the operation of the work machine. The machine also includes an electrically-powered drive assembly coupled to the frame and front and rear axles and an inverter electrically coupled to the electrically-powered drive assembly. The machine further includes a platform assembly disposed adjacent the cab and coupled to the frame. The platform assembly comprises an outer wall at least partially surrounding the inverter. | 07-04-2013 |
20130227937 | RIDE CONTROL SYSTEM - A ride control system and method where the system includes first hydraulics for equalizing pressure between ride control accumulators and boom cylinder head side, and second hydraulics for providing low pressure drop connection between ride control accumulators and boom cylinder head side. When ride control is engaged, the first hydraulics equalizes pressure between ride control accumulators and boom cylinder head side to within a pressure threshold, then the second hydraulics provides the low pressure drop connection between ride control accumulators and boom cylinder head side. Ride control system can include third hydraulics for providing fluid connection between boom cylinder rod side and tank; where after first hydraulics equalizes pressure to within pressure threshold, then third hydraulics provides connection between boom cylinder rod side and tank. The ride control system can also monitor the condition of the ride control accumulators. | 09-05-2013 |