Patent GB-803135-A (GB)
Title: Improvements in or relating to tractors, in particular agricultural tractors
IPC: A01B71/00
Filed: 1955-03-14
Abstract: 803,135. Tractor power-take-off mechanisms. PORSCHE, F. March 14, 1955 [April 14, 1954], No. 7351/55. Class 79(2) A tractor has a power-take-off shaft 27, Fig. 1, and a change-speed gear 4-9 adapted to provide a plurality of speed changes for forward running and having a gear train 11-13, 20-22, for operating a reverse-drive countershaft 19 to provide a corresponding number of reverse speed changes, the power-take-off shaft 27 being adapted to be driven at a constant speed from the tractor engine through a reduction gear 31, 29, independently of the change-speed gear 4-9, as well as to be driven, alternatively, in dependence on the speed of travel of the tractor, by the reverse drive countershaft 19 which is rotated by the change-speed gear 4-9 during the travel of the tractor, whether the tractor is, travelling in the forward or reverse direction and whatever the speed adjustment of the change-speed gear 4-9. An engine driven shaft 2, Fig. 2,. can drive at its side a countershaft 3, at three speeds, through gears 7, 4; 8, 5; or 9, 6. A gear 13 integral with the shaft 3 is in constant mesh with a gear 11 integral with an, intermediate shaft 10, coaxial with the shaft 2 and having another integral gear 12. Coaxial with the shaft 3 is a shaft 14 connected to the tractor rear axle through a bevel gear 15 and crown wheel 16. Slidable but non- rotatable on the shaft 14 are internal gears 22, 23 provided with an internal gear 24. The gears 22, 23 engage integral gears 20, 21 slidable but non-rotatable on the hollow reverse - drive countershaft 19 mounted below the shaft 10. The gears 22, 23 may be moved so that gear 24 engages the gear 13 and the gear 23 engages the gear 20 or so that the gear 23 engages the gear 12 and the gear 22 engages the gear 21. The gears 20, 21 may be moved from the position shown, Figs. 1 and 2, to a position wherein the gear 21 engages the gear 12 and the gear 20 engages the gear 23, whereby a reverse drive for the tractor is effected. Rotatably mounted in the hollow shaft 19 is the power-take-off shaft 27 which rotatably carries the gear 29 in constant mesh with the gear 31 on a hollow shaft 32 mounted on the shaft 2 and also driven from the tractor engine. The powertake-off shaft 27 may be connected either to the gear 29 on the hollow shaft 19 by means of a slidable clutch 26 operable by a lever 34, Fig. 3. The gear 29 may serve to drive auxiliary equipment, e.g. a hydraulic pump. When the gear 23 is engaged with the gear 12 the tractor and power-take-off shaft may be driven at three low speeds through the gears 13, 11 and 12, 13 and 22, 21. If the gear 21 is engaged with the gear 12 the tractor may be driven in reverse at three speeds and the direction of rotation of the power-takeoff shaft will be reversed. When the gear 24 is engaged with the gear 13 the tractor and power-take-off shaft may be driven at three high speeds. If the gear 29 is engaged by the clutch 26 the shaft 27 will be rotated in the reverse direction at a speed directly proportional to the speed of the engine.