Hydraulic stabilizing systems are well known and typically used for elevating off-road machinery while it is parked. For example, a set of four hydraulic jacks (or six) may be used to elevate a rock crusher which is mounted on a semi-trailer type of frame while the rock crusher is being operated on site. After operation and the rock crusher is to be moved, the jacks are retracted, placing the rock crusher back on its wheels to be moved over the road.
In prior hydraulic stabilizing systems of this type, the jacks were typically manually operated using manually-operable valves. The human operator of the system could use a level on the bed of the machine and operate the valves so as to elevate the respective corners so as to achieve a level orientation. Hydraulic stabilizing systems have also been known to be used in larger motorized recreational vehicles, i.e. in motor homes. These are typically four-jack systems with one jack at each corner of the motor home, and these have been automatically operated with electronic push buttons, so that the operator of the vehicle could either push one button and all four jacks extend to place the vehicle in a level orientation, or one button would be provided for each jack, and a light would come on at each button that needed to be extended further to achieve a level orientation. When it was time to the lower the vehicle, a retract button would be pressed which would retract all the jacks to prepare the vehicle for transportation over the road. Individual cylinder retract buttons could also be pressed, as well as individual cylinder extend buttons, to achieve orientations other than level.
In many types of equipment, it is desirable after the initial level orientation is achieved, to be able to automatically extend the jacks or stabilizers while maintaining the vehicle level, and also to retract them while maintaining the vehicle level. Accordingly, it is an object of the invention to provide such a system.