Patent GB-681173-A (GB)
Title: Improvements in or relating to variable-speed power transmission systems
IPC: F16H47/06
Filed: 1949-08-08
Abstract: 681,173. Change-speed gear. HUMBER, Ltd., KAMPER, A. M., and BERRY, G. Oct. 26, 1950 [Aug. 8, 1949], No. 20597/49. Class 80 (ii). On a motor-vehicle, an electrically-shifted reduced - direct - reverse countershaft gear 20 follows a three-element hydrodynamic torqueconverter 5 having the usual overrunning reactor 7 and also a double electromagnetic friction or eddy-current clutch Y, X for selecting respectively converter or direct mechanical drive to the input 2 of the countershaft gear, either drive being available in both direct and reduced ratios. Push-button manual control, with alternative output-speed-responsive control of three drive-conditions is provided. In the countershaft gear the direct-reduced and reverse shift-forks, 30, 57 respectively, Figs. 1 and 5, acting on a synchronised dog 31 and sliding reverse idler for meshing teeth 35, 37, are actuated by a single arm 32 which, for selection, is cross-shifted by a solenoid 60, Fig. 10, acting through a rock-shaft 63, Fig. 5, to slide the arm 32 axially on splines on an executive shaft 33, which latter is then turned to move the selected fork to operative positions, by a reversible electric motor 50, which drives the shaft 33 through an electromagnetic friction clutch 54, energised with the motor, double planetary reducing gear, Fig. 4 (not shown}, and worm-gear 53, Fig. 5. Fast on the executive shaft 33 is a cam disc 85 with lift-segments 81-84, Figs. 5 and 10, which, by lifting balls 80, selectively earth contacts 71, 72, 73, 74, constituting circuit-preparing and limit switches in the main shift-circuit. The main shift-circuit, Fig. 10, is controlled through push-button energised relays a, b ... y. h, such that during all rotation of the shift-motor 50 to actuate the countershaft selector, both converter and mechanical drive clutches Y, X are de-energised, the current-supply contacts of their relays a, b being fed through contacts of a relay f, which is always energised with the shift motor 50 to engage its clutch 54 and simultaneously cut out feed to the main clutch relaycontacts. With both relays a and b de-energised, feed, with the relay f de-energised, is to the converter drive clutch Y and, with either relay a or b separately energised, is to the mechanical drive clutch X. The direction of rotation of the shift-motor 50 is determined by opposite field windings H, L in series with the armature 50, and respectively energised through contacts of relays g or h for up or downshift. Push-buttons DH &c., mechanically interlocked for automatic release of a superseded button, selectively energise the various relays a &c. to provide the following conditions: DH, mechanical-drive clutch X, countershaft in direct; CH converter-drive clutch Y, countershaft in direct; CL converter-drive clutch Y, countershaft in low; N, converter-drive clutch Y, countershaft in neutral; E mechanical-drive clutch X, countershaft in low; R, converter-drive clutch Y, countershaft in reverse. Conditions are shown after selection of neutral by depressing button N. This energises a neutralising relay e, to complete circuits from a battery 103 through both motor-control relays g, h, to the shiftoperated earthing contacts 71, 72 respectively. If the shift to neutral is to be made from low or reverse, the lift 83 of the shift-turned cam 85 will be initially earthing contact 72, resulting in energisation of the upshift relay g to energise the field winding H for shift towards high, the circuit being broken in the mid neutral position shown, by a cam lift 83 opening contact 72. During the shift the motorclutch relay f, in series with the armature of the shift-motor 50, energises the shift-motor clutch 54 and de-energises the main clutches X, Y, the latter being subsequently re-energised when the shift-circuit breaks. If the gear were previously in high, contact 71 of the shift-operated switch 85 will be initially closed by the lift 82, resulting in energisation of the downshift field L by the relay h. During a shift between low and high in countershaft gear, the contacts 73, 74, operated by the common lift 84 of the shift-turned cam 85, are respectively effective to ensure completion and final break of the circuit through the appropriate up and down shift-relays g, h. If the shift involves also a change from the converter-drive clutch Y to the mechanical-drive clutch X, relay a or b is energised alone, the former if shift is to mechanical low, the latter for mechanical high, energisation of the clutch X awaiting de-energising of the shift-motor clutch relay f at the end of the countershaft shift. If the shift from converter to mechanical drive is not to be accompanied by shift in the countershaft gear the relay a or b takes effect immediately on push-button depression to change from clutch Y to X, and vice versa. The remaining relays c, d are effective for reverse, depression of the reverse button R completing a circuit through the relay c as far as contacts 45, 46 which are maintained open during forward rotation of the output shaft 3 by oil-drag between ratchet-toothed members, one 40, Fig. 3, fast to the shaft 3 and rotating with slight clearance in the other 41 which, in the absence of drag, is pressed by a spring 43 to close the contacts 45, 46 and permit completion of the reverse-circuit. With the contacts 45, 46 closed, depression of the reverse button R thus energises the relay c, which directly energises the cross-shift solenoid 60. The reverse shift can be made only after the gear has been moved to the neutral position, shown, by depressing the button N, so that the solenoid 60 is immediately effective for cross-shift, and at the same time closes contacts 110 completing the energising circuit of the relay d. A circuit is now completed from the battery through the downshift relay h, middle contact of neutralising relay e (now de-energised), upper contacts of energised relays d, c, and the contact 70 of the shift-turned cam switch 85, now earthed in the neutral position. The shift-motor 50 is thus energised in the L direction, together with the shift-motor clutch 54, to establish reverse, with final circuit break at 70. The main clutch-control relays a, b remain de-energised and their contacts ineffective until de-energising of the shift-motor clutch-relay f at the end of the shift, feeds the relay contacts a, b to energise the converter-drive clutch Y. For the alternative automatic control, Fig. 11, not shown, an additional push-button marked AUT actuates a relay cutting out all the manual push-button circuits and substituting control by an output driven centrifugal governor operating successively three sets of contacts controlling relay-contacts which take the place of the contacts of push-buttons CL, CH and DH, giving automatic up and downshift between converterlow, converter-high and mechanical-high. Specification 632,028 is referred to.