STEERING ARRANGEMENT FOR A TRACK-LAYING VEHICLE

1,227,311. Endless-track vehicle transmissions. H. W. SCHWEPPENHAUSER and C. KNAPP. 23 Nov., 1966 [22 Dec., 1965], No. 52533/66. Heading B7H. A track-laying vehicle is driven from an input shaft 1 connected through a gear-box 2 to shafts 3, 4, the shafts 3, 4 driving through sun-andplanet gears 5, 6, shafts 15, 16 carrying chain wheels 17, 18 driving the vehicle tracks. For normal straight motion of the vehicle the sunwheels 10, 14 of the gears 5, 6 are held stationary by toothed wheels 19, 21 connected thereto, the wheel 19 being coupled to a steering shaft 24 via a wheel 20 and the wheel 21 being coupled to the shaft via wheels 22, 23. Thus shaft 24 is stationary and serves as a lock for the gears 5, 6 for straight vehicle motion. For steering, the shaft 24 is rotated in the appropriate direction and at a speed corresponding to the radius of turn and to this end a further output shaft 25 from the gear-box 2 drives through bevel gears 26, 27, 28 sun-and-planet gears 29, 30, the planet carriers 33, 37 being connected to the shaft 24 and rotating the shaft in opposite directions when the respective sun-wheel 34, 38 is locked by a respective fluid brake 43, 44, the sun-wheels being connected through hollow shafts 41, 42 to the rotors 45, 47 of the brakes. In normal straight motion of the vehicle the brakes are empty so that the rotors freely rotate and to steer the vehicle the correct brake 43 or 44 is filled with a desired amount of fluid from a pressure line 52 by appropriate operation of a valve 51 so that the fluid flows along line 53 or 54. The desired retarding torque imposed on the corresponding sun-wheel 34 or 38 causes rotation of the shaft 24 in a direction such that the rotational speed of one of the chain wheels 17, 18 increases and the speed of the other decreases by the required amount. In a modification, Fig. 4, the steering shaft 24 is replaced by two shafts 92, 93 which are normally stationary but are rotatable in opposite directions by the sun-and-planet gear 80 or 81, these gears being controlled by fluid brakes 82, 83, also, the gearwheel 22 of Fig. 1 is omitted. The planet carriers transmit the drive to the shafts 92, 93 via bevel wheels 88 ... 91. Thus in dependence upon which brake is filled with fluid the shafts 92, 93 are rotated in the appropriate opposite directions to steer the vehicle.