Patent ID: 11885081
Assignee: CATERPILLAR PAVING PRODUCTS INC.
Field: Mechanical elements (Mechanical engineering)
Classification: CPC E  B  F | IPC E  F

Claim 0:
1. A propelled milling machine comprising:
a machine frame supported on a plurality of propulsion components for travel over a work surface,
an internal combustion engine supported on the machine frame and operatively associated with the plurality of propulsion components for propelling the propelled milling machine;
a cutting rotor rotatably supported by the machine frame for milling a work surface;
a rotor drive transmission operatively driven by the internal combustion engine and operatively associated with the cutting rotor to rotate the cutting rotor with respect to the machine frame, the rotor drive transmission including a plurality of gears selectively engageable with each other to adjust rotational speed of the cutting rotor, the plurality of gears including at least a high gear ratio and a low gear ratio;
a rotor transmission hydraulic circuit in fluid communication with a hydraulic pump to receive hydraulic fluid and with a fluid reservoir to return hydraulic fluid, the rotor transmission hydraulic circuit including a hydraulic gearshift actuator operatively associated with the plurality of gears, a gearshift directional control valve to selectively establish fluid communication between the hydraulic gearshift actuator and one of the hydraulic pump and the fluid reservoir, and a gearshift trapping valve disposed in fluid communication between the hydraulic gearshift actuator and the gearshift directional control valve, the gearshift trapping valve configured to maintain hydraulic pressure in the hydraulic gearshift actuator in occurrence of a fault condition, the rotor transmission hydraulic circuit further including a pressure sensor to measure hydraulic pressure therein, and
an electronic controller in electronic communication with the rotor transmission hydraulic circuit and the pressure sensor, and the fault condition is a pressure loss event with the rotor transmission hydraulic circuit as sensed by the pressure sensor.