US3340945A

US3340945A - Ground effect vehicles

Info

Publication number: US3340945A
Application number: US482678A
Authority: US
Inventors: Alfred R Pearson; Derek J Hardy
Original assignee: Westland Aircraft Ltd
Current assignee: Westland Group PLC
Priority date: 1964-09-03
Filing date: 1965-08-26
Publication date: 1967-09-12
Anticipated expiration: 1984-09-12
Also published as: SE312728B

Description

Sept. 12,1967 R PEARSON ET AL 3,340,945

GROUND EFFECT VEHICLES Filed Aug. 26, 1965 ILLIHIHJ FIG.2

United States Patent ABSTRACT OF THE DISCLOSURE A device for regulating the supply of air to a main air cushion according to variations in the distance between the device and an adjacent surface includes a flexible and freely suspended membrane forming a cavity facing the adjacent surface. The membrane is associated with an air supply duct directing an approximately constant flow of air to the underside of the membrane, and is further arranged as a throttle for the air supply to the main air cushion. As applied to air cushion vehicles, the device can be incorporated in the skirt of the vehicle, or a series of the devices can form all or a substantial part of the skirt.

This invention relates to a sensing device which, when operated in conjunction with an adjacent surface, may be used to sense the distance between the device and the surface.

It is an object of the invention to provide a device which will sense its height above the surface over which it is operating without making contact with the surface, without the use of electronic, barometric, or other complicated sensing arrangements, and will regulate the supply of air to a main air cushion according to variations in the distance between the device and the surface, and which is relatively cheap and simple to construct and to operate.

According to the invention we provide a sensing and regulating device for regulating the supply of air to a main air cushion according to variations in the distance between the device and an adjacent surface, comprising a horizontally disposed diaphragm member having a port formed therein for the passage of pressurized air, first and second flexible wall members connected to opposite edges of the diaphragm member and depending downwardly therefrom toward an adjacent surface, the lower edges of the flexible wall members being inclined in the same general direction whereby one lower edge is inclined inwardly toward the center of the device and the other lower edge is inclined outwardly relative to the center of the device. A flexible membrane is suspended between and has portions of its outer extremities secured to the two flexible wall members to form with the inwardly inclined lower edge an air nozzle directed inwardly toward the center of the device to supply air to the space under the flexible membrane and to form with the outwardly inclined lower edge an air nozzle directed outwardly relative to the center of the device toward an area intended to be maintained as an air cushion. Means are provided flexibly supporting the central portion of the flexible membrane from another part of the device, or if desired from the vehicle or other machine with which the device is associated, so as to have the flexible membrane form with the adjacent surface a cavity. Pressure variations in the cavity act against and move the flexible membrane to regulate the outwardly directed air nozzle, these pressure variations depending upon the distance between the device and an adjacent surface. The preferred embodiment of the invention is as part or all of the skirt of an air cushion vehicle. In effect the membrane senses variations in the distance between the device and the adjacent 3,340,945 Patented Sept. 12, 1967 "ice surface, and regulates the supply of air to the main air cushion according to variations in this distance.

Further objects and advantages of the invention will become more readily apparent from the following detailed description of an embodiment of the invention as applied to an air cushion vehicle, with reference to the accompanying drawings, which is by way of example only, and in which:

FIGURE 1 is a sectional elevation of a device according to the invention, provided at the lower end of a segment-of a flexible skirt of an air cushion vehicle.

FIGURE 2 is a plan view of the device illustrated in FIGURE 1.

In an air cushion vehicle in which the air or gas is conducted to peripheral jet nozzles by ducts. 1, each peripheral jet nozzle forms part of the device according to the invention. A diaphragm 2, of substantially square planform and provided with a port 9, is located across the lower end of each duct 1. Vertical diaphragms 5 and 6 depend from the edges of the diaphragm 2, substantially at right angles to the main air or gas cushion upon which the vehicle is supported, and act as the boundary between adjacent jet nozzles.

Flexible walls

11 and 12 depend from the remaining two sides of the diaphragm 2. A semi-rigid member 13, such as a cable or length of wire, is suspended beneath the diaphragm 2 by way of tension members 14, e.g. lengths of cord. An airtight membrane 10 is suspended from the semi-rigid member 13 and

flexible cross-members

3 and 4 are provided linking adjacent portions of the airtight membrane 10 with the

flexible walls

11 and 12, so that

flexible jet nozzles

15 and 16 are formed. The

flexible jet nozzles

15 and 16 are directed towards the main air cushion, which would be to the right as viewed in FIG- URE 1.

When in'operation over a surface 8, air or gas is fed from the pressure generating means of the air cushion vehicle (not shown) through the skirt duct 1, and the port 9 of the diaphragm 2 to the

nozzles

15 and 16 by way of the passages formed between the airtight membrane 10 and the

flexible walls

11 and 12. In accordance with the well known air cushion vehicle principle, air or gas issuing from the

nozzles

15 and 16 acts as a barrier, and an air or gas pressurised cushion builds up in chamber 7 formed between the airtight membrane 10 and the surface 8. The elficiency of the seal produced by air or gas issuing from the

nozzles

15 and 16 depends upon the mass of air which is expelled, and the distance between the nozzles and the surface over which they are operating. Therefore, if the mass flow of air is kept constant, a variation in the distance between the nozzle and the surface will result in avariation inthe pressure in the chamber. These pressure variations in chamber 7 act upon suspended membrane 10 to raise or lower it depending upon the pressure variation. As is clear from FIGURE 1, an increase of pressure in chamber 7 will tend to move membrane 10 upwardly, which movement will tend to also move membrane 10 toward flexible wall 12, thus reducing the opening of nozzle 16, and regulating the air that passes to the main air cushion through nozzle 16. Thus in effect the membrane 10 senses variations in the distance between the device and the adjacent surface, and regulates the supply of air to the main air cushion according to variations in this distance.

It will be obvious to those skilled in the art that the invention need not be restricted to an air cushion vehicle. Also the invention need not be restricted to air cushion vehicles which have a plurality of ducts in side by side relationship with each other, as hereinbefore described, but that a single device with a jet nozzle adapted to form at least part of the lateral boundary round part of the chamber of the sensing device can be arranged as an efficient sensing unit. In such a unit the jet nozzle may be directed inwardly or vertically downwards.

It will be apparent that this device depends on the three parameters, distance between the device and a surface, mass flow of air at the jet nozzles, and pressure within the chamber, and that if any one of these parameters is held constant, variation of a second parameter is sensed by the resultant variation of the third parameter. It will also be apparent that this device can be used for sensing the clearance between the device and an adjacent object, and thus used as a means for gauging or measuring objects by following the contour of same. Likewise, rates of flow of gaseous fluids could be ascertained by maintaining the distance from an adjacent surface constant and using the changes in pressure to indicate rates of flow. In further applications the device may be mounted in a relatively fixed position, and the rate of flow may be determined by the movement of an adjacent plate-like member.

It will be further apparent that such a device, as hereinbefore described, could be used in conjunction with flexible components adapted to maintain a vessel, such as a ship or an air cushion supported vehicle, at a distance from surfaces other than horizontal surfaces, such as quayside walls and the like.

In yet a further application of the invention the device could advantageously be used with air cushion supported trains adapted to travel along preformed trackways. In such an application of this invention the sensing device could be arranged so as to co-operate with one or more of the sides of the trackway, such that undesired changes in the distance between the trackway and the device could be sensed and used to ope-rate valve means to overcome these undesired effects.

We claim as our invention:

1. A sensing and regulating deivce for regulating the supply of air to a main air cushion according to variations in the distance between said device and an adjacent surface, comprising a horizontally disposed diaphragm member having a port formed therein for the passage of pressurized air, first and second flexible wall members connected to opposite edges of said diaphragm member and depending downwardly therefrom toward an adjacent surface, the lower edges of said flexible wall members being inclined in the same general direction whereby one lower edge is inclined inwardly toward the center of the device and the other lower edge is inclined outwardly relative to the center of the device, a flexible membrane suspended between, and having portions of its outer extremities secured to, said two flexible well members to form with said inwardly inclined lower edge an air nozzle directed inwardly toward the center of the device to supply air to the space under said flexible membrane and to form with said outwardly inclined lower edge an air nozzle directed outwardly relative to the center of the device toward an area intended to be maintained as a main air cushion, means flexibly supporting the central portion of said flexible membrane from another part of said device so as to have said flexible membrane form with said adjacent surface a cavity, whereby pressure variations in said cavity act against and move said flexible membrane to regulate said outwardly directed air nozzle.

2. A flexible ski-rt component for an air cushion vehicle, comprising a flexible structure for connection to the vehicle to depend downwardly therefrom toward the adjacent surface over which the vehicle operates, said flexible structure being hollow with spaced Walls and terminating in an air nozzle so inclined as to direct air inwardly toward the underside of the vehicle when the structure is connected to a vehicle, said flexible structure including a flexible membrane having portions of its outer extremities secured to the lower wall portions of said flexible hollow structure and forming one movable wall of said air nozzle, means flexibly supporting the central portion of said flexible membrane from another part of the device so as to have said flexible membrane form a cavity facing the adjacent surface, said flexible structure including duct means for directing a substantially constant flow of air to the cavity defined by said flexible membrane, whereby pressure variations in said cavity act against and move said flexible membrane to regulate said air nozzle, which pressure variations vary according to variations in the distance between the device and the surface over which the vehicle operates.

References Cited UNITED STATES PATENTS 3,139,947 7/1964 Beardsley 180'7 3,182,740 5/1965 Cookerell l'7 3,240,282 3/1966 Taylor l'80----7 A. HARRY LEVY, Primary Examiner,

Claims

1. A SENSING AND REGULATING DEVICE FOR REGULATING THE SUPPLY OF AIR TO A MAIN AIR CUSHION ACCORDING TO VARIATIONS IN THE DISTANCE BETWEEN SAID DEVICE AND AN ADJACENT SURFACE, COMPRISING A HORIZONTALLY DISPOSED DIAPHRAGM MEMBER HAVING A PORT FORMED THEREIN FOR THE PASSAGE OF PRESSURIZED AIR, FIRST AND SECOND FLEXIBLE WALL MEMBERS CONNECTED TO OPPOSITE EDGES OF SAID DIAPHRAGM MEMBER AND DEPENDING DOWNWARDLY THEREFROM TOWARD AN ADJACENT SURFACE, THE LOWER EDGES OF SAID FLEXIBLE WALL MEMBERS BEING INCLINED IN THE SAME GENERAL DIRECTION WHEREBY ONE LOWER EDGE IS INCLINED INWARDLY TOWARD THE CENTER OF THE DEVICE AND THE OTHER LOWER EDGE IS INCLINED OUTWARDLY RELATIVE TO THE CENTER OF THE DEVICE, A FLEXIBLE MEMBRANE SUSPENDED BETWEEN, AND HAVING PORTIONS OF ITS OUTER EXTREMITIES SECURED TO, SAID TWO FLEXIBLE WELL MEMBERS TO FORM WITH SAID INWARDLY INCLINED LOWER EDGE AN AIR NOZZLE DIRECTED INWARDLY TOWARD THE CENTER OF THE DEVICE TO SUPPLY AIR TO THE SPACE UNDER SAID FLEXIBLE MEMBRANE AND TO FORM WITH SAID OUTWARDLY INCLINED LOWER EDGE AN AIR NOZZLE DIRECTED OUTWARDLY RELATIVE TO THE CENTER OF THE DEVICE TOWARD AN AREA INTENDED TO BE MAINTAINED AS A MAIN AIR CUSHION, MEANS FLEXIBLY SUPPORTING THE CENTRAL PORTION OF SAID FLEXIBLE MEMBRANE FROM ANOTHER PART OF SAID DEVICE SO AS TO HAVE SAID FLEXIBLE MEMBRANE FORM WITH SAID ADJACENT SURFACE A CAVITY, WHEREBY PRESSURE VARIATIONS IN SAID CAVITY ACT AGAINST AND MOVE SAID FLEXIBLE MEMBRANE TO REGULATE SAID OUTWARDLY DIRECTED AIR NOZZLE.