Patent GB-1083898-A (GB)
Title: Improvements in or relating to belt conveyors
IPC: B65G21/04
Filed: 1964-09-17
Abstract: 1,083,898. Endless conveyers; winches. WESTINGHOUSE AIR BRAKE CO. Sept. 17, 1964 [Sept. 24, 1963], No. 38044/64. Headings B8A and B8B. An endless belt conveyer 10 for conveying material from the hopper 28 of a tunnel boring machine comprises a pair of laterally spaced ropes 11 on which belt supporting rollers 13 are carried, and a pair of rotatable winding drums 46, 47 coupled together through a differential gear, each drum winding one of the ropes 11, the drive to the drums to tension the ropes being transmitted through the differential gear whereby the two ropes are equally tensioned. The endless belt 14 is driven around inbye and adjustable outbye pulleys 27, 16 by motordriven pulleys 18, 19. The return run of the belt is fed through belt storage pulleys 24, 26, the latter being longitudinally movable with a carriage 25 to tension the belt. The carriage 25 is connected by a rope 35 to a winch 40 which is mounted on a longitudinally movable carriage spring-loaded by springs 55 to tension the belt 14. The ropes 11 attached to framework at the outbye end of the conveyer by connectors 29 are supported along their length on stands 31, 37, 38, 39. At their inbye ends, the ropes 11 are connected to an anchor member 84, from which two further ropes 86 and 87 extend to the tensioning unit where they pass over inclined pulleys 41, 43, 44 and on to the upper and lower winding drums 46, 47. A further pair of ropes 48 support the belt rollers inbye of the tensioning unit adjacent the hopper 28. The tunnel boring machine is fixed to the inbye end of the conveyer 10, the whole being longitudinally movable with incorporated trucks 64 running on a pair of rails secured in the tunnel. The rope tensioning unit is mounted on a framework integral with the conveyer inbye end framework. The latter unit comprises a carriage 114 carrying the drums 46, 47 and longitudinally movable against compression springs 116, 117 by means of wheels 109, 111, 112, 113, engaging rails 107, 108. The ropes 86, 87 are guided from the pulleys 43, 44 by sheaves 123, 124, 126, 127 and spooling sheave assemblies 136, 137 which are movable along the winding drums on screws 133, driven through gearing from the associated drum. The drums 46, 47 are drivingly connected to the differential gear 163 through gear-wheels and shafts 161, 162. The differential gear is driven depending on a clutch position either from a manually controlled auxiliary motor 171 or from a main motor. The drive-from the main motor is taken through a reversible transmission the output shaft of which incorporates a solenoid operated brake. The reversible transmission is controlled by a cam-actuated lever, the cam being moved through linkage 216 by the relative movement of the frame of the tensioning unit and the carriage 114 thereof. A manual jogging switch is operated to take up the initial tension in the ropes until the required tension is reached whereupon the reversible transmission is in a neutral position and the brake is applied, whereupon the driving system becomes automatic in response to the rope tension. As the tunnelling proceeds and the effective length of the conveyer increases, belt is taken from the storage pulleys and the demand for more rope causes carriage 114 to move relative to the frame of the unit whereby the reversible transmission is switched into a position to unwind the drums while releasing the brake. When the correct tension is reached the transmission again becomes neutral and the brake re-applied. Limit switches cut out the drive motor if too much rope is wound on the drums or if there is no rope left thereon.