Patent GB-950474-A (GB)
Title: Improved tractor power-take-off drive
IPC: F16D67/04
Filed: 1960-10-27
Abstract: 950,474. Tractor power take-offs. MASSEY-FERGUSON Inc. Oct. 27, 1960 [Nov. 4, 1959], No. 36902/60. Heading B7H. [Also in Division F2] A tractor power take-off driving system for a take-off shaft projecting from the rear of the tractor comprises a disconnectible coupling whereby the power take-off shaft may be driven from the output shaft of the tractor change speed gear, and thereby through the tractor main clutch, a driving shaft driven from the engine independently of the main clutch and connectible to the power take-off shaft through a second clutch which is controllable in conjunction with the disconnectible drive by a handle having three positions of operation, one in which the second clutch is engaged and the disconnectible drive is disengaged, one providing the opposite conditions, and a neutral position. The engine is located at the front of the tractor and drives a flywheel 15 with which is associated the main friction clutch 17 and a change speed gear 19, the output shaft 20 of which drives the wheels 11 through a differential gear 12. A tubular shaft 27 is connected to a housing member 28 and is driven continuously from the flywheel 15 and a shaft 25, driven from the shaft 27 through pinions 27 and 30, extends through the tubular shaft 31 of the change speed gear and drives, through an extension 33 and coupling 34, the main pump P of the hydraulic lift-system and the power take-off shaft 26 through the second clutch assembly 35, or alternatively, the power take-off shaft 26 may be driven at a speed commensurate with the road speed of the tractor from the output shaft 20 of the tractor change speed gear through the disconnectible drive comprising pinions 73 and 74, the clutch 35 being automatically disengaged for this operation. The clutch 35 comprises a member 42 drivingly connected to the shaft extension 33 and having a series of friction discs 45 mounted with freedom of axial movement on splines 46 and a member 43 upon which are formed the gear teeth 73 and having a cylindrical portion 47 splined to the power take-off shaft 26. Friction discs 52 are mounted with freedom of axial movement on splines 53 in the member 43 and are interleaved with the discs 45. The outer and inner part 47 of the member 43 are connected by a web 49 and define between them an annular cylinder in which is located by pins 55 an annular piston 54, sealing rings 56 and 57 being provided. Pressure fluid, admitted from a port 70 into a groove 72 is applied to the piston through passages 72, thereby forcing the discs into driving engagement against a thrust member 60. Upon release of the pressure fluid, a spring 58 causes disengagement of the clutch. The pressure fluid is supplied by continuously operating pump P through a conduit 63 to a valve V, Fig. 4, formed in an arm 69 extending from a collar 69 through which the passage 70 extends. The valve V comprises a spool 65, an inlet passage 66, a port 68 communicating with the passage 70 and a discharge orifice 67, the port 68 being connected by the spool to either the inlet orifice 66 or discharge orifice 67. The spool is moved in one direction by a spring 65a and in the other by an arm 81 of a bell-crank lever, the other arm of which having a claw 80 to slide the pinion 74 along its splines on shaft 20. The bell-crank lever is operated by a handle 75 and a spring- loaded detent is provided to hold the handle in one of three positions which provide for the clutch 35 being engaged with the pinion 74 disengaged, neutral and engagement of clutch 35 with the pinion 74 disengaged. To facilitate engagement of the gears 73 and 74, a brake member is provided on the member 43 and comprises a friction ring 86 secured to the member 43 by screws 88, a friction ring 87 housed within a recess 85 and located against rotation by engagement of notches in its periphery with the screws 88, and a ring 90 non- rotatably attached to the collar 69 by pins 91. The braking force is supplied by the spring 58 acting through the piston 55, pins 55 and actuating shoes 92.