Patent ID: 11932327
Assignee: CATERPILLAR PAVING PRODUCTS INC.
Field: Transport (Mechanical engineering)
Classification: CPC B  F  E | IPC B  E  F

Claim 0:
1. A machine for roadwork comprising:
a frame;
a plurality of ground engaging units including a first ground engaging unit and a second ground engaging unit;
a plurality of vertically moveable legs, each leg connecting one of the plurality of ground engaging units to the frame, the plurality of vertically moveable legs including a first leg connected to the first ground engaging unit and a second leg connected to the second ground engaging unit; and
a hydraulic system to control a height of each of the plurality of vertically moveable legs, the hydraulic system comprising:
a fluid circuit to control fluid between the first leg and the second leg;
a load holding valve to let fluid into and out of the fluid circuit;
a first relief valve to control flow of fluid from the first leg to the second leg in a first direction;
a second relief valve to control flow of fluid from the second leg to the first leg in a second direction; and
a control valve to let fluid into and out of the load holding valve, the control valve connected to a source of pressurized hydraulic fluid and a fluid reservoir;
wherein the control valve is coupled to the load holding valve and connected to the hydraulic circuit between the first and second relief valves.