GB616137A - Mechanical change-speed transmission for locomotion engines of great power - Google Patents

Abstract

616,137. Change-speed gear. COPONAT, A. C. M. H. Aug. 28, 1946, No. 25842. Convention date, Nov. 7, 1944. [Class 80 (ii)] In the transmission of a heavy tracked or rail vehicle, four or eight ratio-shifts in widelyspaced geometrical progression are obtained without power interruption up or down, by the provision of two complete identical two- or four-ratio epicyclic gears 63, 64, driven in parallel at the same speed through friction clutches 13, 13<1>, interlocked by a lever 20 for alternate operation, and connected to the parallel driven shaft 48 through different-sized toothed wheels 39, 41 respectively, the ratio of which is that of the geometrical progression, whilst the ratio between the individual steps of each gear is the square of that ratio. Thus, whilst one gear 63 or 64 is driving, the other 64 or 63 is idle and can be changed for the next shift up or down without difficulty, the shift being subsequently rendered effective instantaneously (e.g. in one-fifth of a second) by changing over the friction clutches 13, 13<1>. The driving wheels 12, 121 of the frictionclutches are simultaneously driven at the same speed through a bevel or planetary reverse-gear 4 by one or more engine shafts 1, each having a fluid-coupling 3. The two identical changespeed gears shown each comprises in series stepped and simple planet trains 33, 36, each yielding solid and reduced drives by clutching or holding their ring-gears by means of two sliding dog clutch-detents, e.g. 28, with synchronizing cones 24, operated directly, by power or automatically through striker-rods 42, 43 and 44, 45, so that each gear provides three reduced ratios and direct-drive between its respective driving shaft 63 or 64 and driven wheel 39 or 41, which latter wheels, through idlers, thus impart eight speeds to the final parallel driven shaft 48. The latter drives track-sprockets through two three-element planet trains, the ring-gears 49, 49<1> of which have external teeth meshing respectively through a reversing idler 55 and directly with a parallel shaft 54 which can be held stationary for straight travel with final speed reduced in the two trains, or be driven in either direction from a constantly driven wheel 56 and a mechanical, electric or hydraulic variable control 57 (not described), to impart controlled speed differences to the ring-gears for steering- purposes. With the main gear in neutral, the shaft 54 can still be driven in either direction for pivoting the vehicle on itself. In a twinengined rail-vehicle drive, Fig. 2 (not shown), the stepped and simple planet trains are arranged on opposite sides of their corresponding driven pinions 39, 41. The Specification as open to inspection under Sect. 91 states also that the usual clutch and accelerator pedals may be eliminated. This subject-matter does not appear in the Specification as accepted.