GB573734A - Improvements in preselective transmissions - Google Patents

Abstract

573,734. Preselector mechanism for variable-speed gearing and signalling apparatus. DERUNGS, E. A. June 28, 1943, No. 10435. Convention date, Dec. 23, 1941. [Class 80 (ii)] Preselector control mechanism for variablespeed gearing or railway signalling apparatus comprises selecting tilting members 11, pivoted at 14 on a block 15 which is guided for up-anddown movements by a slot 26 and a fixed pin 1. Each tilting member 11 has slots 17, 18, abutments 21, 22, 50 ... 53, and cylindrical faces 19, 20, described about the pin 14 as centre. Each tilting member lies between a member 2 pivoted on the pin 1 and comprising a pair of plates connected by pins 5 ... 10, of which pins 5, 7, 8, 10 coact with a tilting member 11 and the pins 6, 9 are connected with the.parts to be actuated, e.g. gear change members. Associated with each tilting member 11 is a pair of spring-urged plungers 30, 32, of which 32 can be adjusted by a cam 37, 38 or 39, rotatable about a rod 31 fixed to the block 15. The latter is connected to the forked end 48 of a lever H pivoted on a fixed pin I and linked to an operating lever F. According to the position,of the plunger 30 the tilting member, provided it is free to move, can take up three positions, viz. : two inclined in which either abutment 50 or 51 abuts against the block 15, or a central non-inclined position. The parts of the block 15 engageable by the abutments 50, 51, may be spring-supported. In operation, to preselect a new working condition, the cam carrier 35 is rotated to vary the -spring tension of the plungers 30. When the desired change is to be made, the lever F is actuated to rock the lever H and cause upward and downward movement of the block 15. During the upward movement such members 2 which are to be changed are brought into the central or neutral position and the tilting members take up their new positions and upon the downward movement the 'thrust is transmitted from the block 15 to one or other of the abutments 50, 51 and thence to the members 2 by the projections 52 or 53 and pins 5 or 10. The plungers 30 may be springless. In this case preselection is made after the block 15 has been raised.