Patent GB-935825-A (GB)
Title: Improvements in or relating to vehicles for travelling over land and/or water
Inventor: COCKERELL CHRISTOPHER SYDNEY
IPC: B60V1/06
Filed: 1958-09-01
Abstract: 935,825. Air cushion vehicles. HOVERCRAFT DEVELOPMENT Ltd. Sept. 24, 1959 [Sept. 1, 1958], No. 27978/58. Class 4. A vehicle for travelling over a surface and which in operation is supported above that surface by at least one cushion of pressurized gas formed and contained beneath the vehicle comprises means for causing a fluid to issue from the lower part of the vehicle and flow towards the surface over which the vehicle is supported and form at least one curtain of moving fluid, the cushion of pressurized gas being contained in part by the said curtain of moving fluid and in part by a structure which extends below the main body of the vehicle and is flexible or is flexibly attached to the main body of the vehicle. The body 3 of the vehicle comprises an air intake 9 which supplies air to a compressor 10, the compressed air being led through a duct 11 and flexible pipes 12 to a duct 1. This duct is formed of articulated sections, attached at joints 8, and positioned round the periphery of an articulated or flexible membrane 2 which is secured to the body 3 by a plurality of hydraulic rams 4 through pivotal connections at the ends of the rams, though at least one ram is rigidly attached to the bottom of the body to provide stability and correct positional relationship between the body and the membrane. The duct 1 is formed with inwardly directed ports 14 through which air forming the curtain is discharged, and membrane 2 is curved transversely and maintained thus by the supporting cushion. In operation, the membrane 2 and duct 1 are capable of vertical movement locally in response to obstructions encountered by the vehicle and such vertical movement is subject to restoring forces exerted by the rams. In place of a selfbalancing system as described above the membrane and the sections of the duct 1 may be operated by a servo system responsive either to the pressure within the cushion or in response to a signal from an anticipatory sensing device. For operation in response to cushion pressure, Fig. 16, the curtains from a duct 90 are supplemented by transverse curtains 93 which subdivide the cushion, the sections of duct 90 being attached to the body by double acting rams 92 each connected by conduits 96, 97 to a control valve 106 supplied with pressure fluid from a pump 109. The spool rod 105 of the valve 106 is pivotally connected to one extremity of a centrally pivoted lever 103, the other extremity being connected to a rod 102 attached to a diaphragm 101 of a sealed container 98, the separate compartments of which are respectively responsive through pipe 115 to a source 116 of pressure and through pipe 117 to the pressure in the respective part of the supporting cushion. In operation, when the duct section encounters an obstacle, the resulting rise in pressure in the cushion will be transmitted through pipe 117 to operate diaphragm 101 which, through the connecting linkage, will operate valve 106 to cause ram 92 to raise the duct section. When the obstacle has passed the resulting drop in pressure in the cushion will cause the mechanism to operate in reverse direction to restore the duct to its correct height. In order that duct sections may be operated in anticipation of approaching obstacles, the sensor pipe 117, or a float hydrofoil, skid or wheel, may be connected to the mechanism for operating duct sections located aft of the sensor, a sensor being positioned forward of the vehicle to operate the first section of duct. Further embodiments incorporate ducts secured to the body by arms which are resiliently mounted by links attached to the wall of annular inflatable chambers or are resiliently supported by telescopic shock absorbers and in one still further embodiment the lower, resiliently mounted structure, is formed wholly from inflatable compartments incorporating telescopic shock absorbers. The body may be mounted on a plurality of individual supporting structures, each of which carries its own annular duct and compressors for forming a curtain. A still further embodiment, Figs. 20, 21, (not shown), is described in which the body is attached to wheels which support directly or through resilient means, approximately 10% of the weight of the vehicle, the remaining 90% being supported by the cushion, the subsidiary supports deflecting the duct directly or by servo means when an obstacle is encountered. Means such as retractable jacks are provided to assist in supporting the vehicle when the curtain and cushion are not being generated. Specifications 854,211 and 919,350 are referred to.