Patent GB-702839-A (GB)
Title: Improvements in or relating to governors
Inventor: GATISS ALBERT LESLIE
IPC: F16H61/02
Filed: 1950-11-03
Abstract: 702,839. Change-speed control. BROCKHOUSE ENGINEERING (SOUTHPORT), Ltd. Nov. 5. 1951 [Nov. 3, 19501, No. 28830/50. Class 80 (2) and 80 (3) A two-position valve 54, controlling the supply and exhaust of oil pressure through a delivery duct 28 to the actuating piston of a direct-drive friction disc-clutch in a torque-eonverter-driven planetary gear as described in Specifications 639,675 and 702,840, and actuated through a yielding spring link by a governor responsive to output speed and torque as described in the latter Specification, is subjected to the action of a pressure-responsive dashpot piston 77, which, after initiation of a shift movement in either direction supplies oil pressure to urge apart two locking elements 71, 72, a corresponding one of which depresses one or other pair of locking balls 67, 68 into a corresponding groove 65 or 66 in the shift-valve 54 as soon as the latter completes its shift movement, thereby positively locking the shift-valve 54 in its new position until, after a pre-determined time-interval, the dashpot piston 77 supplies pressure to the outer faces of the locking elements 71, 72 urging them inwards (position shown), to unlock the shiftvalve 54 for a return shift in the opposite direction if the governor so dictates. The governor is thus unable to make a return shift until after the expiration of the pre-determined time-interval and hunting is thereby avoided. Valve ports 58, 59 and 60 are continuously connected with a main pressure inlet 55 when a manual valve 56 is in the open position, shown. In the clutch-disengaged (reduced drive) position shown, pressure passes the valve-groove 66 to act on the right face of the dashpot piston 77 holding the latter in its extreme left position shown, wherein pressure from a permanent supply port 79 passes through a dashpot groove 82 port 83 and ducts 84 to the outer faces of the locking- elements 71, 72 which are thereby held in their inward release position in which they are spaced by a block 74. When the speed-torque governor calls for an upshift to direct-drive, it is able immediately to move the shift-valve leftwards through a full stroke to change the clutch line 28 from an exhaust port 64 to a pressure port 58, thus immediately engaging the direct-drive clutch. The same valve movement cuts off pressure from the right face of the dashpot piston 77 and supplies pressure through the port 59 and valve groove 65 to its left face. The dashpot piston 77 immediately commences a rightward movement at a rate determined by bleed holes 97, 98 effective on both its faces, its initial movement exhausting the outer faces of the locking-elements 71, 72 through the port 83, dashpot groove 82 and an exhaust outlet 87, whilst a bottom dashpot groove 88 cuts off an exhaust outlet 90 and supplies pressure from a permanent inlet 81 through a port 89 to the space between the locking elements 71, 72, which are immediately urged apart so that the element 72 presses the balls 68 into the valve-groove 66 thus locking the valve 54. The dashpot piston 77 continues its rightward movement at the controlled rate until it reaches its extreme right position in which the lower dashpot groove 88 exhausts the inner locking-element space through an outlet 91 and pressurizes. the outer faces of the locking elements from a permanent inlet 80 through the upper dashpot groove 82 and port 83. The shift-valve 54 is thus unlocked for return movement when required. If, during the above interval, the governor operates for a return shift, it merely compresses the spring in the linkage, which effects the return movement of the shift-valve 54 immediately upon its unlocking. The clutch supply line 28 may include a local exhaust valve as described in Specification 702,838. The gear and governor shown in Specification 702,840 are also shown.