Patent GB-718414-A (GB)
Title: Improvements in or relating to change-speed gears
Inventor: KAMPER ANDREW MATHIS
IPC: F16H3/00
Filed: 1950-11-10
Abstract: 718,414. Change-speed control. HUMBER, Ltd. Nov. 9, 1951 [Nov. 10, 1950], No. 27559/50. Class 80 (2) A four-speed and reverse gear is provided by two nested input (or output) magnetic or magnetically operable friction clutches A, B, (see Fig. 1 (Comp)), driving countershaft wheel pairs 1, 2 and 3, 4 respectively providing third speed and direct-drive when the wheel 3 is clutched to the final output (or input) shaft 112 by manually operable mechanical means comprising a synchro-meshed dog or other clutch 113, which, in a rearward position, clutches a third wheel-pair 6 5 to provide first and second ratios. Operation of the dog clutch by  a  manual lever X (see Fig. 1 (Prov.) ), thus controls a 2-3 or, 3-2 shift, whilst operation of a manual switch m changes the input magnetic clutches A, B, controlling the 1-2, 2-1, 3-4 and 4-3 shifts. The magnetic clutches A, B are fed by the engine-driven generator to give automatic engagement with speed increase; are disengaged automatically during a shift by either the lever X or manual switch m, and are automatically changed over by the dog-clutch lever X if inappropriately engaged, e.g. for starting. Starts are normally made in second speed by moving the dog-clutch lever X to the low position, and energizing the magnetic clutch A. Initial movement makes a contact 10 completing two circuits from the battery-line, the first energizing a winding 11 to break the common generatorfeed circuit of both magnetic clutches A, B. Completion of the second circuit depends on whether or not the magnetic clutch B is effective immediately preceding the shift. If it is a winding f will have been energized directly from the battery-line through a throw-over switch j and the manual switch m (in its right hand position) such winding f drawing down a change-over switch arm a, to feed the magnetic clutch B, and a coupled switch-arm b to make a contact 14 leading to the contact 10 on the dog-clutch shift-lever X. Under these conditions the second circuit above referred to will be completed from the battery-line through series contacts p, o (broken by the lever X on completion of the shift) a solenoid winding d switch arm b, contact 14, contact 10 and the earthed shiftlever X. Energization of the solenoid d turns a ratchet switch e arranged for alternate make and break at each successive energization. In this instance the switch e makes, and from the batteryline energizes a winding h drawing down the throw-over switch j to connect with the now dead contact of the manual switch m, thus breaking the circuit of the winding f, whereupon the change-over switch a reverts to its upper position feeding the magnetic clutch A. On completion of the movement of the dog-clutch X, the switch o is opened to de-energize the solenoid d, and on release of the lever, means (not shown) breaks the contact 10 to de-energize the winding 11 permitting closure of the switch to feed the clutch A from the generator. If, at the time of this shift to second speed, the clutch A had already been engaged (change-over switch a in upper position) the above circuit to the solenoid d would not be completed and no change of the clutch circuit would occur. In this position of the dog-clutch lever X, movement of the manual switch m between its two positions effects shifts between second and first speeds by alternately energizing and de-energizing the winding f of the change-over switch a of the magnetic clutches A, B. During movement of the manual switch m between its extreme positions a circuit is broken from the battery-line through windings k, l either one of which is energized in the extreme positions of the switch m to close a switch in the generator-fed common line to the clutches A, B, whereby during movement of the switch m both clutches are disengaged to provide a dwell. Upshift from second to third speeds requires movement of the dog-clutch lever X to the high position and coincidental change from clutch A to B. In this case contact 20 is made and the clutch circuit is broken initially by the winding 21, the change-over-switch a being operated to select clutch B by energization of the solenoid d acting as above described on the winding f. In this position of the dog-clutch lever X, shifts between third and fourth speeds (direct-drive) are made by the manual switch m, to change over the clutches A, B as above described for the first-second shift. Reverse is selected in the low position of the dog-clutch lever X by means not described. Specifications 610,594, [Group XXXV], 610,595, 645,700, 645,728, and 681,010 are referred to.