Patent GB-802582-A (GB)
Title: Improvements in or relating to controlling change-ratio transmissions in motor vehicles
Inventor: SIMPSON CYRIL MAURICE
IPC: F16H63/30
Filed: 1956-01-10
Abstract: 802,582. Change-speed control. BIRMINGHAM SMALL ARMS CO., Ltd. Jan. 30, 1957 [Jan. 10, 1956], No. 771/56. Class 80 (2). Change-speed gear control mechanism for a motor vehicle, such as a tractor, having a planetary change-speed gear 35 of the Wilson type in which the gear ratios are pre-selected by manual means, comprises a fuel supply means 3 closed during a ratio shift by fluid-operated means 1 associated with manual means 29, &c. controlling the setting of the throttle, a manually-operated valve controlling the fluidoperated means 1 and working in conjunction with lever and link mechanism 21, 31, &c. to actuate both the fuel control means and the ratio establishing mechanism of the changespeed gear. The fuel control means may be the carburetter of a petrol engine or the fuel injection pump of a Diesel engine, and the fluidoperated means may be either pneumatically or hydraulically actuated. In the form shown, a compressor driven by the tractor engine supplies air through a valve to a reservoir, whence it is fed through a hand control valve to a servomotor actuated to establish the various ratios in the Wilson gear 35. Compressed air is simultaneously fed from the servomotor to a cylinder 1 containing a piston connected by a rod 7 to a bar 9 formed with a slot 11. A pin 13 on the end of a lever 15 engages with lost motion in the slot 11. The other end of the lever 15 is connected by a link 17 to the throttle of the carburetter 3 of the tractor engine, a spring biasing the link 17 to the throttle-closed position. The lever 15 is also connected through links &c. 21, 23, 25, 27 and a flexible strut connection 37 &c. to a hand control lever 29. A releasable ratchet 45 holds the hand lever 29 in any desired position. The flexible strut connection 37 between the link 29 and the hand lever 29 comprises a strut 39, Fig. 3, engaged at its ends 41, 41 with the link 27 and with a projection 36 on the lever 29, tension springs 37, 37 biasing the projection 36 and the links 27 towards each other. In operation, the hand lever 29 is moved to adjust the setting of the throttle of the carburetter 3 to a desired position, and is then held by its ratchet 45. To obtain a new ratio, the desired ratio is manually pre-selected, and the hand control is opened to supply compressed air to the servomotor, which initiates movements of links 31 &c. to establish the new ratio. Simultaneously, compressed air is supplied to the cylinder 1 to move the piston which it contains, together with the rod 7 and bar 9, leftwards of Fig. 2. At first the bar 9 moves freely relatively to the stud 13, until the lost motion between the stud and the slot 11 has been taken up. Continued movement of the bar 9 then turns the lever 15, and pulls the link 17 against the bias of its associated spring to close the throttle of the carburetter 3, simultaneously stretching the springs 37 in the flexible strut connection between the handle 29 and link 27. When the new ratio has been established, the springs 37 &c. restore the links 17, 21, &c. to their original position, thus re-opening the throttle and returning it to its previous setting. Specification 697,732 is referred to.