Motor vehicles – Surface effect vehicles – Flexible skirt
Patent
1994-06-09
1996-03-26
Focarino, Margaret A.
Motor vehicles
Surface effect vehicles
Flexible skirt
180129, B60V 116
Patent
active
055012914
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to filament member for a skirt for an air cushion vehicle which has beneath the bottom of the vehicle hull a number of air cushion chambers which are delimited in horizontal direction by the skirt and into which air supply means may blow air for maintaining the air cushion in the air cushion chamber during operation of the vehicle, the skirt including elongated, downwards extending filaments.
2. Description of the Prior Art
A skirt for an air cushion vehicle is known from the U.S. Pat. Nos. 3,249,167 and 3,172,494 showing skirts with brushes in the form of rods, wires, cords, chains or filaments made of plastic.
Another skirt is known from SE-B-305812, where skirt members are hanging down from the hull. The flexible skirt members are shaped with large cross-sections merging into each other such as triangular cross-sections with the apex facing alternatively inwards and outwards. These skirt members are not of the filament type.
The skirt extends along the periphery of the air cushion chambers and serves to prevent the air from freely escaping the chambers. In the traditional air cushion vehicles the skirt is constructed from a continuous rubber sheet, but such a sheet is frequently exposed to damage when the air cushion vehicle crosses obstacles which may seize the skirt.
A skirt of brushes as known from the above U.S.A.-patents possess the advantage that obstacles may pass freely through the brushes without damaging these.
It is a well known problem of air cushion vehicles that they hardly can be used in waters where there is risk of icing up because the ice is easily formed on the skirt and impedes the correct functioning thereof. This problem is especially distinct by the brushformed skirts having a very large surface area compared to the length of the skirt. As air cushion vehicles are very sensitive to weight changes even smaller deposits of ice on the skirt may demand suspension of the vehicle operation.
The object of the invention is to provide a skirt more appropriate for navigation in cold waters.
With this aim the filament member according to the invention is characterized in that the filament member has an upper base portion with engagement means for the attachment of the member to a retainer, and that the member includes several juxtaposed elongated filaments extending from the base portion and having less cross-sectional area at the free end of the filaments than at the root thereof. Such a member may in a simple manner be manufactured from a plastics material by means of injection moulding and it provides for assembling a skirt having any desired length simply by placing in the retainer a number of members corresponding to the desired skirt length. As each member only comprises comparatively few filaments such a skirt is repairable at low-costs in the event of skirt damages, because only the damaged members are to be replaced.
SUMMARY OF INVENTION
By designing the filaments with less cross sectional area at their lower ends, that are most frequently in contact with the water and consequently especially exposed to icing, they are here substantially more flexible than at their upper ends. The larger flexibility results in larger deflections and more rapid movements in the lower section of the skirt, thereby enabling any deposited ice to loosen and fall off the skirt. The larger cross-sectional area in the upper part of the filaments ensures that the skirt preserves sufficient stiffness in order to keep the air inside the air cushion chamber. The embodiment according to the invention thus gives due consideration to the conflicting considerations that the skirt must have the sufficient stiffness to confine the air, but also a flexibility to prevent icing. With the view of further preventing ice formations on a skirt the filament member is advantageously designed so that at the base portion there is at least one flow passage which may set at least one interspace between the filaments in flow communication with a chambe
REFERENCES:
patent: 3055446 (1962-09-01), Vaughen
patent: 3172494 (1965-03-01), Cockerell
patent: 3208543 (1965-09-01), Crowley
patent: 3249167 (1966-05-01), Tibbetts
patent: 3273663 (1966-09-01), Cockerell
patent: 3333650 (1967-08-01), Hardy et al.
patent: 3468395 (1969-09-01), Winter
patent: 3662851 (1972-05-01), Ramsey
patent: 4702332 (1987-10-01), Prentice
Dan/Hover c/o Leif Qvist
Focarino Margaret A.
Johnson Victor E.
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