Steering drive for track-laying vehicles

Claim 1

In a vehicle having ground-engaging members at the opposite sides adapted for being driven at the same speed to drive the vehicle in a straight line and at different speeds to cause the vehicle to turn: an engine, power-conveying means driven by said engine and having an output shaft for each ground engaging member, said output shafts rotating in the same direction and at the same speed, a differential transmission for each groundengaging member having an output element connected to the respective ground-engaging member and an input element connected to the respective said output shaft and a reaction element rotatable in a first direction to increase the speed of the pertaining output element relative to the speed of the pertaining input element when said reaction member is at a standstill and in a second direction to decrease the speed of the pertaining output element relative to the speed of the pertaining input element, a one-to-one drive connecting said reaction elements and arranged so rotation of either reaction element in its said first direction will be accompanied by rotation of the other thereof in its said second direction and at the same speed, counterrotating drive means connected to said one-to-one drive, control means connected in controlling relation to said counterrotating drive means for selectively actuating said counterrotating drive means in a selected direction to operate said vehicle with turning thereof and for halting said counterrotating drive means to operate the vehicle without turning thereof, said control means comprising a differential having an input member driven by said engine and also having an output member and a reaction member, first and second clutches interposed between said output member and said counterrotating drive means individually energizable to provide for respectively opposite directions of rotation of said one-to-one drive and both energizable to lock said counterrotating drive means against rotation, and a variable brake connected to said reaction member, said control means further comprising a lever having a neutral position, means establishing connection relative to neutral position of said lever wherein both of said clutches are energized and said variable brake is unactuated whilE said lever is in the neutral position, and additional means establishing further connection due to said lever being moveable from said neutral position in opposite directions to deenergize respective ones of said clutches, said lever being operable upon said latter additional means to actuate said variable brake to a degree conforming to the amount of movement of said lever in either direction from said central neutral position.

Claim 15

The method of controlling the direction of movement of a vehicle having ground-engaging drive members on opposite sides, said vehicle also having an engine and a power flow path from the engine to each drive member and each power flow path having a differential transmission therein with a reaction member rotatable in opposite directions to increase or decrease the speed, respectively, of the drive member relative to that of the engine, one-to-one reversing drive means, interconnecting said reaction members so rotation of one in one direction will cause rotation of the other in the other direction, counterrotating shafts each drivingly connected to said reversing drive means, a variable brake, the rotor of said brake being driven through a differential, the reaction member of said differential being connected to a common first part of two clutches the second parts of the clutches being connected to the counterrotating shafts, respectively, the method consisting in closing both of said clutches when driving the vehicle in straight direction and releasing one of said clutches and actuating said variable brake and controlling the rotational speed of said rotor when turning right and releasing the other of said clutches and again actuating said variable brake and controlling the rotational speed of said rotor when turning left, the rotational speed of said rotor being a measure for the curvature of turning in both cases turning right or left.

Claim 16

The method of controlling the direction of movement of a vehicle having ground-engaging drive members on opposite sides, said vehicle also having an engine and a power flow path from the engine to each drive member and each power flow path having a differential transmission therein with a reaction member rotatable in opposite directions to increase or decrease the speed, respectively, of the drive member relative to that of the engine, one-to-one reversing drive means, interconnecting said reaction members so rotation of one in one direction will cause rotation of the other in the other direction, counterrotating shafts each drivingly connected to said reversing drive means, a variable brake, the rotor of said brake being driven through a differential, the reaction member of said differential being connected to a common first part of two clutches the second parts of the clutches being connected to the counterrotating shafts, respectively, the method consisting in closing both of said clutches when driving the vehicle in straight direction and releasing one of said clutches and actuating said variable brake and controlling the rotational speed of said rotor when turning right and releasing the other of said clutches and again actuating said variable brake and controlling the rotational speed of said rotor when turning left, the rotational speed of said rotor being a measure for the curvature of turning in both cases turning right or left.