Multi-range hydraulic drive

A multi-speed drive for driving a driven motive member, comprising the combination of a driven unit having at least one output connectable to the motive member and having at least first and second inputs, a clutch unit connected to the first drive unit input, a first fixed displacement hydraulic motor connected to the clutch unit so as to drive the drive unit first input through the clutch when the clutch is engaged, a brake unit connected to the second drive input, a second fixed displacement hydraulic motor connected to the brake unit so as to drive the drive unit second input when the brake is disengaged, a variable displacement hydraulic pump, hydraulic circuit means for delivering the pressurized hydraulic fluid to the first and to the second hydraulic motors, control valve means for distributing the pressurized hydraulic fluid to both the first and second motors to provide a relatively low speed, high torque drive for the motive member, and alternatively to the second motor only to provide a relatively high speed, low torque drive to the motive member, charging means for providing a pressurized hydraulic fluid at a constant pressure, additional hydraulic circuit means for delivering hydraulic fluid from the charging means to the clutch, valve means for selectively directing the hydraulic fluid to the clutch and alternatively away from the clutch to a reservoir for correspondingly urging the clutch into a clutch-disengaged condition and for alternatively permitting the clutch to reach a clutch-engaged condition, additional hydraulic circuit means for delivering hydraulic fluid from the charging means to the brake, and valve means for selectively directing the hydraulic fluid to the brake so as to urge the brake into a brake-disengaged position, and alternatively for diverting fluid away from the brake to a reservoir to permit the brake to reach a brake-engaged condition.