US3620325A - Deformable skirting system for surface effect machine - Google Patents

Deformable skirting system for surface effect machine Download PDF

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Publication number
US3620325A
US3620325A US870543*A US3620325DA US3620325A US 3620325 A US3620325 A US 3620325A US 3620325D A US3620325D A US 3620325DA US 3620325 A US3620325 A US 3620325A
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US
United States
Prior art keywords
skirting system
reticulated
coating
parallels
brace
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US870543*A
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English (en)
Inventor
Marc Faure
Louis Arsandaux
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Societe dEtudes et de Developpement des Aeroglisseurs Marins SEDAM SA
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Societe dEtudes et de Developpement des Aeroglisseurs Marins SEDAM SA
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60V—AIR-CUSHION VEHICLES
    • B60V1/00—Air-cushion
    • B60V1/16—Flexible skirts
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24058—Structurally defined web or sheet [e.g., overall dimension, etc.] including grain, strips, or filamentary elements in respective layers or components in angular relation
    • Y10T428/24074—Strand or strand-portions
    • Y10T428/24091—Strand or strand-portions with additional layer[s]

Definitions

  • a ground effect machine having a deformable skirt of heterogeneous structure which comprises (i) a flexible reticulated reinforcement structure formed of an interwoven array of wires or cables, and (ii) a flexible fluidtight lining which embeds or is otherwise joined to said reticulated structure and which is formed of a closed continuous surface, said wires or cables being oppositely inclined with respect to meridian lines of said lining surface as well as to parallels thereof.
  • the present invention relates to a deformable skirting system for air cushion vehicles or other surface effect machines, which forms a flexible sidewall for a plenum chamber in which the pressure fluid cushion is formed.
  • Such defonnable skirts are often given in practice a tapering outline at least adjacent their free end with a cross section which is circular or part circular, e.g. a frustoconical shape, as described in BERTIN U.S. Pat. No. 3,388,766.
  • the present invention relates more specifically to a deformable skirt of heterogeneous structure comprising a flexible coating of fluidtight material forming a closed continuous surface having meridian lines-e.g. generatrices in the case of a surface of revolutiondefined by the intersections of said surface with longitudinal planes and parallels-cg. directrices in the above-mentioned case-defined by the intersections of said surface with transverse planes, said flexible coating being joined to a flexible reticulated brace formed of an interlocked meshwork of wires, cables, filaments or the like (hereinafter referred to as wires").
  • wires a flexible reticulated brace formed of an interlocked meshwork of wires, cables, filaments or the like
  • said wires have opposite inclinations with respect to both said meridian lines and said parallels.
  • said wires extend along helices in one or more layers, the helices forming, with said transverse planes, an angle whose tangent is smaller than or equal to l/Ji, that is an angle smaller than or equal to 35.4".
  • any increase in load causes a decrease in skirt height, resulting in a decrease in vertical accelerations over waves or uneven ground.
  • FIG. I is a view in vertical section, showing a skirt according to the invention.
  • FIG. 2 is an explanatory diagram
  • FIG. 3 is a plan view of a lobated skirt with flexible partitions forming ties
  • FIG. 4 is a view in elevation of a partition tie taken along arrowfin FIG. 3;
  • FIG. 5 shows part of an embodiment of meshwork
  • FIG. 6 is a section along line VlVl in FIG. 5.
  • FIGS. 7, 8 and 9 are schematic fragmentary cross sections illustrating three different space relationship between the fluidtight coating and the meshwork of wires.
  • FIG. 1 diagrammatically shows a platform I of a ground ef fect vehicle equipped with a ducted fan 2 supplying compressed air to a supporting cushion 3 bounded at the top and bottom respectively by the said platform 1 and the ground or water surface 4, and bounded at the sides by a flexible skirt 5 of circular cross section, tapering towards the free bottom end 6 adjacent the surface 4, and attached at its opposite end 7 underneath platform 1.
  • the skirt comprises a reticulated flexible brace structure 8 (for the sake of simplicity, the structure is shown only in the central part of FIG. 1) comprising an interlocked meshwork of wires made of textile, glass. steel or other materials.
  • the wires form two symmetrical layers or series of layers arranged in helices forming an angle a 35.4 approximately (tangent e l/J2 on either side ofa horizontal plane.
  • wires of the interlocked meshwork 8 have opposite inclinations with respect to meridian lines of the skirt 5 as well as to parallels thereof.
  • the meridian lines may be defined as being the intersections of the skirt with longitudinal (vertical) planes whereas the parallels would be defined as being the intersections with transverse (horizontal) planes.
  • the skirt is a body of revolution
  • the meridian lines are generatrices
  • the parallels are directrices.
  • the skirt is made fluidtight and stiffened by a rubber or plastics coating 50 which may be applied over the flexible reticulated structure 8 (see FIG. 7); alternatively the latter may be embedded in the material of the coating 50 (see FIG. 8) or spaced therefrom (see FIG. 9) and in this latter case a mere attachment at the ends 6, 7 of the skirt may be provided between the two components.
  • a rubber or plastics coating 50 which may be applied over the flexible reticulated structure 8 (see FIG. 7); alternatively the latter may be embedded in the material of the coating 50 (see FIG. 8) or spaced therefrom (see FIG. 9) and in this latter case a mere attachment at the ends 6, 7 of the skirt may be provided between the two components.
  • skirt 5 When at rest, skirt 5 is shaped in the form indicated by the dotted line in FIG. 1, having a curved cross section which is concave towards the outside.
  • skirt 5 Under operating conditions, the internal pressure forces skirt 5 into the cross section shown by solid lines.
  • This curve from the attachment end 7 downwards, comprises a substantially toroidal element 5a which gradually changes into a frustoconical element 5b of low conicity (0 to 10") which in turn is bounded by a substantially frustoconical element 5c of greater conicity.
  • the horizontal force P11 is proportional to the relative pressure in the skirt and to its surface, and therefore the diameter of the skirt. As the skirt is slightly conical, the force decreases slightly from top to bottom. At the bottom, the force decreases rapidly because of the considerable decrease in static pressure inside the skirt.
  • the second force is the vertical force Fv, due to the weight and to the conicity of the skirt. It reaches its maximum value at the top and decreases steadily to zero at the bottom. At is maximum, Fv is of the order of 10 to 20 percent of Fh.
  • the equilibrium position of the skirt would give values of a of the order of 5 to 10 at the top and less than 1 at the bottom.
  • the value of a is less than approximately 35.
  • the equilibrium position will correspond to a value of a which decreases as the load increases (since pressure increases and so does Fh) and in proportion to the elasticity modulus of the coating material which is now stressed.
  • the device thus has a reduced general rigidity.
  • General rigidity denotes the ratio dF/dH where dF is the variation in the load and dH is the resulting variation in the hoverheight of platform 1. Clearly, a reduction in general rigidity is desirable for a good suspension effect.
  • Meshwork 8 which has been described for a skirt of circular cross section, can be applied to skirts having a number of lobes such as those denoted by 5' in FIG. 3 which have a cross section bounded by circular arcs.
  • the meshwork may extend on the outer containing wall and/or on the inner dividing partitions (see FIG. 4).
  • the reticulated structure 8 of wires can be constructed in various ways.
  • FIGS. 5 and 6, by way of example, show an embodiment comprising a multiplicity of deformable loops 10 interconnected at four equidistant points by rings ll and assuming a rhomboidal shape.
  • the material for the coating (not shown) can subsequently be cast over the loops to form the coating.
  • a deformable skirting system for a surface effect machine comprising a flexible coating of fluidtight material forming a continuous endless surface of a geometric shape admitting of meridian lines and parallels, and a flexible reticulated brace joined to said coating and formed of an interlocked meshwork of first threadlike members having an inclination in one angular direction with respect to both said meridian lines and said parallels, and of second threadlike members having a like inclination in the opposite angular direction with respect to both said meridian lines and said parallels.
  • said reticulated brace comprises a meshwork formed of successive deformable generally quadrangular loops and interlocking means securing adjacent vertices of said loops to each other.

Landscapes

  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Body Structure For Vehicles (AREA)
  • Elimination Of Static Electricity (AREA)
  • Fluid-Damping Devices (AREA)
  • Air Bags (AREA)
  • Ropes Or Cables (AREA)
US870543*A 1967-06-08 1968-06-10 Deformable skirting system for surface effect machine Expired - Lifetime US3620325A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR109638 1967-06-08

Publications (1)

Publication Number Publication Date
US3620325A true US3620325A (en) 1971-11-16

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ID=8632633

Family Applications (1)

Application Number Title Priority Date Filing Date
US870543*A Expired - Lifetime US3620325A (en) 1967-06-08 1968-06-10 Deformable skirting system for surface effect machine

Country Status (3)

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US (1) US3620325A (enExample)
FR (1) FR1567032A (enExample)
GB (1) GB1225378A (enExample)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4339017A (en) * 1978-09-25 1982-07-13 Payne Carson R Air cushion vehicle skirt material and method

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US526546A (en) * 1894-09-25 Alexander straus
US1334796A (en) * 1919-06-16 1920-03-23 Beaver Company Compound board
US1427708A (en) * 1919-04-23 1922-08-29 North British Rubber Co Ltd Balloon fabric and the like
US3211246A (en) * 1961-09-13 1965-10-12 Vickers Armstrongs Ltd Air cushion vehicle
US3212627A (en) * 1962-10-31 1965-10-19 Dunlop Rubber Co Reinforced mechanical belting
US3327797A (en) * 1965-05-07 1967-06-27 Bertin & Cie Ground effect vehicle with detachable flexible skirt
US3371738A (en) * 1962-01-11 1968-03-05 Bertin & Cie Surface effect devices with skirt height adjusting means
US3438457A (en) * 1966-02-01 1969-04-15 Bertin & Cie Multi-cushion system for a surface effect vehicle
US3511331A (en) * 1966-07-25 1970-05-12 Pneumatiques Caoutchouc Mfg Skirts for vehicles propelled on air cushions

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US526546A (en) * 1894-09-25 Alexander straus
US1427708A (en) * 1919-04-23 1922-08-29 North British Rubber Co Ltd Balloon fabric and the like
US1334796A (en) * 1919-06-16 1920-03-23 Beaver Company Compound board
US3211246A (en) * 1961-09-13 1965-10-12 Vickers Armstrongs Ltd Air cushion vehicle
US3371738A (en) * 1962-01-11 1968-03-05 Bertin & Cie Surface effect devices with skirt height adjusting means
US3212627A (en) * 1962-10-31 1965-10-19 Dunlop Rubber Co Reinforced mechanical belting
US3327797A (en) * 1965-05-07 1967-06-27 Bertin & Cie Ground effect vehicle with detachable flexible skirt
US3438457A (en) * 1966-02-01 1969-04-15 Bertin & Cie Multi-cushion system for a surface effect vehicle
US3511331A (en) * 1966-07-25 1970-05-12 Pneumatiques Caoutchouc Mfg Skirts for vehicles propelled on air cushions

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4339017A (en) * 1978-09-25 1982-07-13 Payne Carson R Air cushion vehicle skirt material and method

Also Published As

Publication number Publication date
GB1225378A (enExample) 1971-03-17
DE1756560A1 (de) 1970-04-16
FR1567032A (enExample) 1969-05-16

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