Patent ID: 11889790
Assignee: DOUGHERTY FORESTRY MANUFACTURING, LTD. CO.
Field: Other special machines (Mechanical engineering)
Classification: CPC A  F | IPC A  F

Claim 0:
1. A hydraulically powered implement for use in connection with a tractor that has a hydraulic pump that supplies pressurized hydraulic fluid to the implement, the implement comprising:
a variable displacement hydraulic motor that has a maximum speed, a maximum speed displacement volume, and a minimum speed displacement volume;
an operative element driven by the hydraulic motor;
a speed sensor configured to measure the rotational speed of the operative element and output a speed signal representative of the measured speed;
a shift module that adjusts the displacement volume of the hydraulic motor in response to a shift command signal; and
a controller, wherein the controller sends the shift command signal to the shift module in response to the speed signal output by the speed sensor when the measured speed is less than the maximum speed and the rotational speed of the operative element is decreasing, wherein the shift command signal sets the hydraulic motor at an adjusted displacement volume that is smaller than a linearly equivalent displacement volume, where the linearly equivalent displacement volume is the displacement volume between the maximum speed displacement volume and the minimum speed displacement volume that linearly corresponds to a ratio of the measured speed between the maximum speed and the minimum speed.