GB1326699A - Automatic speed-limiting system for a body driven by a linear induction motor - Google Patents

Abstract

1326699 Railway systems MERLIN GERIN 29 Nov 1971 55349/71 Heading B7L Apparatus for synchronizing the speed of a first body, e.g. a cabin 12 with that of a further body, e.g. a supporting and drive cable 10 before take-up of the drive by the cable 10 as the cabin leaves a station comprises an acceleration carriage 20 which accelerates along a track 28 under the action of a linear induction motor (not shown) and which is coupled to a protrusion 22 on the cable clamp 14 of the cabin 12 by means of a mating recess 24 provided on the underside of the carriage 20, the clamp 14 having wheels 18 which support the cabin on tracks 16 at the station and which serve to uncouple the clamp from the cable, the apparatus also comprising a chain 38 driven at a speed synchronous with that of the cable 10 by means of a roller 46 driven by the cable and a drive transmission 44, the chain 38 having lugs 36 thereon which can pivot in one direction only about their mountings, the arrangement being such that the lugs 36 will pivot over the body of the carriage 20 as long as the chain is moving more quickly than the carriage but movement of the carriage at a greater rate than the chain and thus the cable 10 is particularly prevented by engagement of the carriage with one of the lugs, e.g. the lug 36<SP>111</SP> shown in Fig. 1. Thus the cabins 12 are accelerated, on leaving the station, to the speed of the cable 10 and held at this speed by the intermediary of the linear motor drive carriage 20 and the action of the lugs 36 on the chain 38, the clamps 14 being engaged with the cable as the wheels 18 leave the tracks 16. At the end of its run the carriage 28 may be driven back along the track 28 by the linear motor by suitable switching of the supply current thereto. The carriage 20 may be dispensed with if desired, the linear motor acting directly on the body of the clamp 14 of the cabin. In an alternative embodiment (Fig. 4) vehicles as 52 are driven along rails 56 by means of a linear induction motor 58, 60. At stations where it is desired to reduce the speed of a vehicle 52 to that of a moving platform in the form of an endless belt 62 driven between end rollers by a motor 66, a wheel 70 mounted on a shaft 72 on the vehicle fractionally engages with the belt 62, the wheel 70 being mounted on the shaft 72 for rotation in one direction only, e.g. by means of a unidirectional clutch mechanism such as a pawl and ratchet, such that the locking of the unidirectional clutch mechanism and the friction between the wheel 70 and the belt 62 will prevent overrunning of the vehicle 52 relative to the belt 62 in spite of the linear motor drive thereto, the speed of the vehicle 52 being held at that of the belt 62 at the station. The vehicles 52 may be suspended by fluid or magnetic cushions and a single track 56 may be flanked on each side by a moving platform belt 62 respectively serving opposite directions of travel of vehicles along the track.