Patent GB-693830-A (GB)
Title: Improvements in or relating to electrical control means for change speed gearing
Inventor: MILLER ALBERT ARTHUR
IPC: F16H61/02
Filed: 1950-06-05
Abstract: 693,830. Switches held set and freed mechanically; centrifugal switches. M. & W. PATENTS, Ltd. May 30, 1951 [June 5, 1950], No. 13963/50. Class 38 (v) [Also in Group XXIV] In a system for controlling a mechanical changespeed gear, e.g. of the epicyclic type wherein solenoids 63, 44, 48, 52, 55 operate valves controlling reaction brakes and for clutches of reverse and four forward speeds respectively, a manually operated selector switch, Figs. 3 and 4, co-operates with the circuits of an automatic switch, Figs. 5 and 7, which last-named is responsive to engine-speed and accelerator-pedal position and is supplied with current from stud 115, Fig. 1 of the manual selector switch in its "automatic" position 4 only. Centrifugal switch. This comprises, see Figs. 5 and 7, an engine-driven shaft 141 pivotally carrying centrifugal roller masses 152 which, with increase in engine speed, thrust leftwards on a plate 156 and internal plunger 162 to rock a spring-loaded member 143 carrying contact-studs 145 engageable with a pair of profiled contact-plates which are insulated from each other and control respectively upshift and down shift circuits in the change-speed gear, being represented diagrammatically by the profiled plates 2, 3 in Fig. 1, in which the governormoved member is the arm 1. The contact plates 148 are carved on an insulating base on a rockshaft 147 linked to the engine-throttle and thus varying the engine-speeds at which the contacts are made in accordance with accelerator-pedal position. Manual selector switch. A manual shift-lever 94, Figs. 3 and 4, moves in an H-gate between positions 1, 2, 3, 4 and R for selecting amongst the circuits of four speeds and reverse, the latter being reached only after depressing a reverse lock-out button 105. To the lever 94 is secured a contact-plate 90 carrying electrically connected diametral arms 87, 87, 88, 89, which turn with the lever 94 to track contacts as shown in Fig. 1. The vertical cross-shift movements of the lever 94 through the gate-slot 104 are permitted by pivots 98a and rock the plate 90 to cause the arm 87 to bear against underlying contacts 115, 116, 117 when the lever 94 occupies the upper gate-slot, 4, 3 for selecting respectively "automatic" (at position 4), neutral and third (position 3); and to cause the arm 86 to bear against underlying contacts 129, 130, 131, 132, for reverse, first, neutral and second when the shift-lever 94 occupies the lower gate-slot R, 1, 2. In each of the gear positions the shift valve-solenoid G3 &c. is fed from battery positive past connected contacts 125 - 128 through a current economising resistor 65, contacts 120 &c. arm 89, contacts 120 &c. on which the arm 89 bears on all positions of the switch, and contacts 116 &c. or 129 &c. In the central position springs 98 bias the shift lever to a horizontal position with both arms 86, 87 off their contacts, as shown. The pivot-pins 98a of the shift lever and contact-plate assembly 94, 90 are carried by a plate 95, which turns with the shift-lever about central pins 92, 111, and is positively locked in gear positions by a peg 100 thereon engaging notches in a fixed plate 101. Before the shift-lever 94 can be turned between gear positions it is necessary to unlock the peg 100 by pressing a button 107 on the end of the lever 94, which through a spring-loaded wedge 108 and ball 110, thrusts downwardly the entire assembly of plates 90, 95 and lever 94 in opposition to a return-spring 93. In addition to freeing the lock-peg 100, this also causes the fourth contact arm 88 to bear on the underlying contacts 125-128, so that the economising resistor is shortcircuited by the arms 88, 89, and full battery-voltage is applied to the selected valve solenoid 63 &c. during the shift, after which release of the button 107 restores the resistor 65, for reduced voltage during continuous running.