US 12,063,891 B2
Adjustable lift rate system for grass mowing machine
Brent G. Rinholm, Fuquay Varina, NC (US); and Zackary P. Sipper, Raleigh, NC (US)
Assigned to DEERE & COMPANY, Moline, IL (US)
Filed by DEERE & COMPANY, Moline, IL (US)
Filed on Feb. 26, 2020, as Appl. No. 16/802,008.
Prior Publication US 2021/0259154 A1, Aug. 26, 2021
Int. Cl. A01D 75/30 (2006.01); A01D 34/00 (2006.01); A01D 34/44 (2006.01); A01D 34/54 (2006.01); A01D 69/03 (2006.01); A01D 34/64 (2006.01); A01D 34/74 (2006.01)
CPC A01D 75/30 (2013.01) [A01D 34/006 (2013.01); A01D 34/44 (2013.01); A01D 34/54 (2013.01); A01D 69/03 (2013.01); A01D 2034/645 (2013.01); A01D 34/74 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An adjustable lift rate system, comprising:
a riding greensmower having a lift and lower circuit including a plurality of hydraulic lift cylinders to lift and lower a first row of grass mowing units followed by a second row of grass mowing units;
a bypass around the plurality of hydraulic lift cylinders responsive to a proportional solenoid valve;
an operator control on the riding greensmower for commanding the proportional solenoid valve to divert hydraulic fluid from the plurality of hydraulic lift cylinders to the bypass to adjust a lift rate and a lower rate of the first row and the second row of grass mowing units; and
a controller that provides a constant starting current, a ramp of increasing current, and a constant ending current, thereby automatically slowing the lift rate as the grass mowing units approach a top of a lift.