Patent GB-815443-A (GB)
Title: Improvements in or relating to change-speed transmission mechanism
Inventor: ORR PALMER
IPC: F16H63/30
Filed: 1956-10-11
Abstract: 815,443. Change-speed control. BORGWARNER CORPORATION. Oct. 11, 1956, No. 31019/56. Class 80 (2). In a motor vehicle, a main countershaft-type change-speed gear 13 giving three forward ratios and one reverse ratio is in series with a planetary overdrive gear 14, a steering-column mounted shifter lever 98 actuated to select and establish the different ratios in the main changespeed gear 13 conditioning a switch 103 to close contacts 104 when in its second ratio position so that a switch 90 can be closed by an output shaft driven centrifugal governor 79 at a relatively low speed (12 m.p.h.) and thus complete a circuit causing the overdrive gear 14 to give its step-up ratio, movement of the shift lever 98 to its top or direct drive position conditioning the switch 103 to open the contacts 104 and simultaneously close contacts 106 so that a switch 91 now replaces the switch 90 in the planetary gear control circuit, the switch 91 being closed by the governor 79 to engage the overdrive gear step-up ratio at a relatively high speed (25 m.p.h.). The planetary overdrive gear 14 comprises a driving planet carrier 42, a driven toothed annulus 40, a direct drive freewheel 50 which overruns during the step-up ratio, and a reaction sun-gear 39. A braking pawl 56 is introduced into a slot 55 in a brake disc 54 by energization of a solenoid 60 to station the reaction sun-gear 39 and obtain the step-up ratio. The solenoid 60 is in a circuit completed by energization of a relay 108 to close a switch 127 in the circuit containing the switches 103, 90, 91. Engagement and disengagement of the pawl 56 with its slots 55 in the brake disc 54 is obtained by momentary cessation of driving torque from the vehicle engine. The solenoid 60 having been energized by the vehicle attaining a sufficient speed for the governor 84 to close the necessary switch 90 or 91, the braking pawl 56 is moved against the bias of a spring 64 to engage with a balk ring 59. This prevents the engagement of the pawl with one of the slots 55 in the brake disc 54 until the vehicle driver releases the accelerator pedal 120, when the freely rotating sun-gear 39 slows down and then starts to rotate backwardly. The balk ring 59 now allows the pawl 56 to engage one of the slots 55 and obtain the step-up ratio. To obtain a " kick-down " shift in the overdrive gear 14, the driver fully depresses the accelerator pedal 120 and thus conditions a switch 115 by opening its contacts 116 to de-energize the relay 108, which accordingly opens its switch 127 and deenergizes the brake pawl solenoid 60. The reaction torque acting upon the brake pawl 56, is, however, such that the spring 64 is unable to withdraw it from the brake disc slot 55. When the accelerator pedal 120 has been completely depressed, it conditions the switch 115 to close its contacts 118 and connect the primary coil 131 of the engine ignition coil 130 to ground through a closed switch 75, thereby disabling the engine.. The reduction in torque transmitted through the gearing then allows the spring 64 to withdraw the braking pawl 56 from its slot 55 and restore direct drive in the planetary gear 14, withdrawal of the braking pawl 56 simultaneously opening the closed switch 75 so that the primary circuit of the engine ignition is no longer short-circuited, and the engine begins to work again. Specification 679,161 is referred to.