Patent GB-1334874-A (GB)
Title: Air cushion vehicle transportation systems
IPC: B60V3/04
Filed: 1971-05-07
Abstract: 1334874 Railway systems; air cushion vehicles BLISS PENDAIR Ltd 7 May 1971 [7 May 1970] 22078/70 Headings B7L and B7K An air cushion vehicle transportation system comprises a track 8a or 8b presenting an elongated support surface 10, and a vehicle including a body 14 connected by columns 18 to a suspension platform 20, Fig. 7, formed of a tubular beam 24 and wings 26, mounted within the track side walls 12, the ends of the beam each having a pin 66 connecting the platform with a respective end bogie 22 which is substantially positively located relative to the surface 10 by interaction therewith, the surface 10, the platform 20, end plates 54 of the end bogies 22 and the track side walls 12 forming a chamber 28 which is maintained at a sub-atmospheric pressure by fan means 34 in the bogies so as to apply suspension and guidance forces between the platform and the track, the platform 20 being movable relative to the surface 10 and to the plates 54 at least in a direction towards and away from the surface 10. The extraction fans 34 are connected by flexible air hoses 78 to the ends of the beam 24 and the latter has apertures 32 therein communicating with the chamber 28. The side edges of the wings 26 have small clearances with the side walls of the track and may be provided with seals or air curtains as described with reference to Figs. 41 to 53 (not shown). The end bogies 22 are each guided and supported by air cushions trapped by air curtains 36 issuing from beneath walls 50, Fig. 2, and acting on inner surfaces 30 of the track side walls 12, Fig. 7, which cushions are operated at positive pressure, e.g. by air extracted by the fan 34 and supplied to a plenum chamber 52, and also by negative pressure air cushions generated in chambers 38, Fig. 4, defined by suspension plates 40 connected by ducts 42 to the fan 34, the plates 40 being provided with end skirts 44, Fig. 1, and cooperating with dove-tail section sub-tracks within the track 8a or 8b by longitudinal extending projections 46, 48. Thus the bogies whilst free to move longitudinally of the track are severely limited for movement in any other direction. The pin 66 on the end of the beam 24 engages in a slot 64, Fig. 7, in the respective bogie end plate 54 which thus allows the platform to execute both rocking movements laterally of the bogies and movements relative thereto in a direction towards and away from the surface 10 whereby the platform can move from the position shown in dotted lines in Fig. 7 to the position shown in full lines under centrifugal action on track curves. As shown in the right hand half of that Figure the depth of the track is increased on tight curves of the track. The pendulum suspension described above may be damped by introducing friction between the pins 66 and the bogie end plates 54 or by telescopic damper and spring combinations (92) as described with reference to Fig. 13 (not shown). The vehicle is driven by a linear induction motor comprised of motor windings 60 mounted in the bogies 22 and coacting with a reaction plate 47  carried by the projection 48 extending along the track. In another embodiment described with reference to Figs. 18 to 20 (not shown) the end pin (122) is arranged for rotational movement about the longitudinal axis of the beam (118) and vertical movement only relative to the bogie end plate (124). The suspension characteristics can be varied in this embodiment by altering the profile of an obturatable aperture (164) in the bogie end plate and controlled by the vertical movements of the pin (122). According to a further embodiment Figs. 23 to 27 (not shown) the suspension characteristics of the system are controlled by rocking movements of the end pin (200) causing the obturation of the profiled aperture (162) in the bogie end plate (124) which is elongated downwards to accommodate deep and shallow track sections. Instead of the pendular suspension described the platform structure may comprise end portions (304) connected by a narrower spine portion (308) which platform can only move vertically in the track all as described in Figs. 28 to 36 (not shown). As the spine portions negotiate track curves the upper and lower side edges of the spine portions are sealed relative to the track by pivotal seal plates (334), (336) and (344). In order to control rolling, pitching and yawing movements of the vehicle series and or parallel combinations of suspension platforms may be provided as described with reference to Figs. 69 to 75 (not shown). Alternatively lateral movements of the vehicle may be controlled by lateral and vertically disposed platforms operating against a vertical brick wall under selective sub-atmospheric or superatmospheric pressure according to the direction of the lateral force, as described with reference to Figs. 61 to 65 (not shown). Other means of propulsion, e.g. propeller or driving wheels may be used. Moreover the invention may be applied to air cushion vehicles suspended by super-atmospheric pressure in which case the track will not be inverted but of upright channel section. Finally the invention may be applied to free air cushion vehicle and a sustaining surface having no guidance function.