Patent GB-690824-A (GB)
Title: Improvements in or relating to change-speed gearing
IPC: F16H47/08
Filed: 1950-05-08
Abstract: 690,824. Change-speed gearing. HUMBER, Ltd., LIMON,W.; KAMPER, A. M., and BERRY, G. May 3, 1951 [May 8, 1950], No. 11391/.50. Class 80 (ii), In a motor vehicle having a hydraulic torque converter 3 preceding a two-speed and reverse epicyclic gear operated by manually-controlled electro-magnetic brakes and clutches, there is associated with each forward speed a switch which prevents energisation of the corresponding clutch or brake magnet until the clutch or brake parts are synchronised. As shown, the gear comprises a sun 12 on the driven shaft 6 of the converter, a carrier 14 with inter-engaging planets on the driven shaft 15, a reaction sun 17 carrying, through the intermediary of a rubber ring 20, an armature disc 21 which is braked by an electro-magnet 22 for low speed and is frictionally clutched to the carrier 14 by an electro-magnet 23 for direct drive, and a reaction annulus 18 carrying, through a rubber ring 25A, an armature 25 which is braked by an electro-magnet 26 for reverse, control being effected by a hand lever 60 movable in a gate. The low-speed synchronisation switch comprises a contact finger 56 secured to sun 17 and engaging with lost motion in a slot 54 in a slip ring 53 carried by an insulating sleeve 55 frictionally mounted on the fixed casing so as to be capable of slipping, one end of the slot being insulated. The direct-drive synchronisation switch comprises an insulating plug 41 frictionally mounted on the shaft 15 so as to be capable of slip and carrying a contact 45 which is connected to an insulated slip ring 46 and is disposed at one end of a slot in the end of the plug 41, with which slot a projection 47 on the end of shaft 6 engages with lost motion. Direct drive is brought in by moving lever 60 to position D, thereby energising a relay 61. As shaft 6 is at this time over-running shaft 15, switch 45-47 is closed, and a relay 80 is energised to break the circuit to the magnet 23 and also to break the ignition circuit 81. When shaft 15 begins to overtake shaft 6, switch 45- 47 opens to de-energise the relay 80 so as to restore the ignition circuit and complete the circuit to magnet 23. To change-down to low gear, lever 60 is moved to position L, energising a relay 62. At this time, switch 53-56 is closed, so that relay 80 is again energised to break the circuit to magnet 22. As engine speed is increased, until armature 21 begins to rotate reversely, the switch 53-56 opens, deenergising relay 80 and completing the circuit to magnet 22. Reverse is engaged by moving lever 60 to position R, energising a relay 64 to complete the circuit to the magnet 26 and to a solenoid 32 which applies a pawl 30 to teeth on annulus 18 so as to prevent reverse rotation of the latter and reinforce the action of the brake 26. A speed-responsive device 72 driven from shaft 15 operates through a contact 75 to energise a relay 78 above a first pre-determined speed, thereby closing a switch 78<SP>1</SP> in series with the relay coil 80. Below this speed, however, switch 78<SP>1</SP> is open, rendering the synchronisation switches ineffective and permitting gear change without synchronisation. Above a second higher pre-determined speed, the device 72 operates, through a contact 76 to energise a relay 79 which energises a clutch 10 in the converter 3 so as to by-pass the latter. The lever 60 may be moved to a position E, energising a relay 63 for engagement of low gear and engagement of clutch 10 at all speeds.