Patent ID: 7971417

Claim:
An elective down pressure system for cutting units of a grass mowing machine, comprising: a first lift arm supporting a first cutting unit; a second lift arm supporting a second cutting unit; a lift and lower mechanism with a rod connected to the first lift arm and the second lift arm, the rod being retractable to urge the first lift arm to pivot on a first axis and the second lift arm to pivot on a second axis spaced laterally from the first axis to raise the first cutting unit and the second cutting unit to a transport position, or extendable to lower the first cutting unit and the second cutting unit to the ground surface; the lift and lower mechanism having a lost motion coupling that may be set to either a downforce position in which the extended rod applies downforce to the first and the second cutting units after the first and the second cutting units are on the ground surface, or may be set to a no downforce position in which the extended rod does not apply downforce to the first and the second cutting units once the first and the second cutting units are on the ground surface; and a removable pin in the lost motion coupling to set the lost motion coupling to either the downforce position or the no downforce position.