Patent GB-867045-A (GB)
Title: Improvements in or relating to systems of transportation
IPC: B60L13/04
Filed: 1958-08-27
Abstract: 867,045. Levitated transport systems; electric traction; endless conveyers. GENERAL ELECTRIC CO. Ltd., and POLGREEN, G. R. Aug. 24, 1959 [Aug. 27, 1958; Dec. 12, 1958; April 17, 1959], Nos. 27516/58, 40162/58 and 13179/59. Classes 78 (1), 104 (2) and 104 (3). [Also in Groups XXXI, XXXIV and XXXV] In a transport system in which vehicles 3 are propelled along a track 1, permanent magnets 2 and 4 are provided on the track 1 and vehicle 3 and the mutual repulsion between such magnets 2 and 4 reduces the load-bearing contact between the vehicle 3 and the track 1. In the arrangement shown in Figs. 1 and 2 a number of normally continuous longitudinally-extending parallel rows of barium ferrite permanent magnets 2 adhere or are secured to a U-shaped tray 6 resting on a horizontal concrete base 5. Similar permanent magnets 4 adhere or are secured to an inverted U-shaped tray 8 provided on the vehicle 3. The opposed magnets 2 and 4 are so arranged that their surfaces-having like polarity face one another so that the vehicle 3 is levitated by repulsion. Lateral stability of the vehicle 3 is obtained by adjustable spacing brass bolts 9, with or without low-friction material inserts, provided on the side of the trough 8 and engaging the upturned walls of the tray 6. In an alternative arrangement, Fig. 5 (not shown), lateral stability is secured by bolts provided on an inverted channel member arranged on the vehicle and straddling a raised continuous part extending longitudinally of the centre of the trackway. Lateral stability may also be effected by rows of permanent magnets arranged on the vehicle 3 and trackway 1 to exert equal and opposite horizontal forces on the vehicle in the direction normal to the direction of motion. The vehicle is propelled by a row or rows of traction magnets 11 attached to the tray 8 or 6 along the centre line thereof and a row or rows of coils 10 situated along the centre line of the tray 6 or 8. The surfaces of adjacent magnets 11 have opposite polarity and the coils 10 are so connected to an alternating supply source that the upper surfaces of the adjacent coils are, in effect, of opposite magnetic polarity. By connecting groups of coils 10 to alternating current sources of different frequencies the linear speed of the vehicle can be varied, Fig. 4 (not shown). The magnets 2, 4 and 11 and the coils 10 may be enclosed by a thin aluminium cover. In. a further arrangement, Fig. 3 (not shown), a number of vehicles are connected by a flexible linkage, such as a pin, which passes through overlapping portions of adjacent vehicles. A flexible overlapping cover is provided at the joints between the vehicles so that an uninterrupted surface is presented. Vehicle tilt on curves is prevented by spacing the adjacent magnets 2 in the parallel rows on the inside of the curve. The spacing of adjacent magnets 2 in the parallel rows may also be varied on level portions of the track to create an artificial gradient to accelerate or decelerate a vehicle on leaving or entering a station. The vehicle 3 may also be suspended from a " T " shape member, Fig. 6 (not shown), carrying permanent magnets and co-operating with an elevated trackway. In an alternative method of propelling the vehicle electric motors are mounted on vehicle drive wheels which are spring-biased downwards to bear on a part of the trackway. The first Provisional Specification mentions that the vehicle may be propelled by turbo jet or rocket motors which would be provided with a reversible thrust arrangement for braking purposes. The second Provisional Specification mentions that the vehicle may be arranged to straddle a central rail and may be provided with at least two double-flanged wheels to run on the top of the central rail. Numbers of pairs of wheels may also be provided and arranged to bear on opposite sides of the central rail to guide the vehicle. The two wheels running on the top of the central rail may be provided with rubber tyres or alternatively may be fitted with rubber bands or tracks to provide a continuous contact surface along the central rail between the pairs of running wheels. The two sides of the central rail may be fitted with suitable strips of metal insulated from the central rail to provide, in association with a brush gear mounted on the vehicle, a means of electric propulsion and power for the vehicle. A direct current low-voltage may be applied between the two strips to generate a magnetic field on the vehicle which reacts with the flux of the trackway magnets to provide propulsion. The metal strip may be switched from the power supply to a variable resistor or may be short-circuited to provide electromagnetic braking.