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United States Patent 3,658,010
Du Merle April 25, 1972

TRACK FOR GROUND EFFECT MACHINES

Abstract

A track for guided ground effect machines, the track having a machine-supporting portion and a guidance rib and including a passage arranged within the thickness of the said rib to cause the space covering the top of the said rib to be in communication through the said passage with a space defined by the machine-supporting portion of the track and which communicates with the outside atmosphere, whereby redundant lifting forces acting on the machine are substantially avoided.


Inventors: Du Merle; Guy Charles Marie Joseph (Paris, FR)
Assignee: Societe de l'"Aerotrain" (Paris, FR)
Appl. No.: 05/088,639
Filed: November 12, 1970


Foreign Application Priority Data

Nov 15, 1969 [FR] 6939364

Current U.S. Class: 104/23.2 ; 104/120; 104/134; 105/145
Current International Class: B60V 3/00 (20060101); B60V 3/04 (20060101); E01B 25/00 (20060101); E01B 25/10 (20060101); B61b 013/08 (); E01b 025/08 ()
Field of Search: 104/23FS,134,118,120,148LM 105/141,145

References Cited

U.S. Patent Documents
3048127 August 1962 Oberpaul
3096728 July 1963 Amann
3583327 June 1971 Arndt
3233559 February 1966 Smith
Primary Examiner: La Point; Arthur L.
Assistant Examiner: Keen; D. W.

Claims



I claim:

1. A ground effect transportation track for fluid cushion machines, having support and guiding faces therefor, the guiding faces being formed on a rib and including active longitudinal strips which are cushion wetted upon passage of a machine and which bound on said guiding faces adjacent inactive portions located outside normal cushion path, wherein the improvement comprises a vent duct extending within the thickness of said rib from an end located on such an inactive portion to another end located on said track away from said support and guiding faces thereof.

2. A track according to claim 1, wherein the said former end is located at the top of said rib.

3. A track according to claim 2, wherein the said rib is hollow, comprising generally parallel spaced walls which define the said vent duct between them.

4. A track according to claim 3, wherein the machine supporting part of the track is raised to define beneath it a space communicating with the atmosphere, the said spaced parallel walls extending through said machine supporting part and the said vent duct opening into this space.

5. A track according to claim 4, further comprising orifices in the said spaced parallel walls in the region of the junction between these walls and the machine-supporting part of the track.
Description



This invention relates to a track for ground effect machines.

It is known, in a guided ground effect machine employing a track the cross-section of which has, for example, the shape of an inverted T, to provide the machine with a longitudinal slot which cooperates with the projecting central guidance rib through the intermediary of cushions of pressurised fluid located on either side of the said rib. The leaks issuing from these cushions into the upper portion of the slot lead to a state of overpressure within the latter, the result of this on the structure of the machine giving rise to an increase in the lift effect. This increase entails no drawback and indeed, rather, is advantageous at low speeds, but it will be seen hereinafter that this is no longer the case at high speeds.

When the dynamic pressure becomes greater than the pressure of the cushion, such entry of fluid as may occur through the front end of the cushions providing lift does not entail any increase in the pressure of these cushions, which are always kept in balance by the weight of the machine, but it merely entails a slight lifting of the machine, a lifting movement limited by the resulting increase in the leakage from the supporting cushions via their free margin in the direction of the outside atmosphere on the side opposite the guidance rib.

This is not the case with cushions providing guidance, whose front walls may likewise absorb dynamic pressure, because these cushions are set up opposite each other and because their distance away from the central guidance rib, a distance determined by the invariable width of the longitudinal slot appertaining to the machine, is not able to increase as is the case with cushions providing lift. This therefore entails in the said slot an increase in pressure which, acting on the structure of the machine (which is closed in at this spot), brings about a redundant lifting force which increases as the speed does, and is liable to give rise to major disadvantages at very high velocities.

In another connection the leaks issuing from these guidance cushions in the vicinity of the machine-supporting portion of the track are added to the leaks coming from the lift-providing cushions along the said machine-supporting portion, more especially at the re-entrant angles which exist at the junction of the central rib with the machine-supporting portion of the track. This phenomenon gives rise to a differing rate of wear on the inner and outer confining walls of the cushions providing lift. This may be remedied, for example, by a suitable adjustment of the flexibility of the said confining walls, but it may be important to eliminate the cause of this.

In order to minimize these drawbacks, it is therefore important to eliminate the increase in pressure within the slot and, in addition, the increase in pressure which occurs at the re-entrant angle of the track, this being effected by making the slot communicate with the outside atmosphere.

The solution, which consists in providing a passage through the machine itself, can only be practised with difficulty, both because of the bulkiness of the ducts that would be necessary for this purpose and because of the awkwardness of making an appropriate choice as to the areas where these ducts should have port.

The solution finally selected and forming the subject of the present invention consists in providing the guidance rib or ribs of the track with means which render possible communication between the existing slot underneath the machine and a space located beneath the machine-supporting portion of track, the said space being connected to the outside surrounding atmosphere.

According to the invention, the means in question comprise a passage arranged inside the guidance rib and bounded by the substantially vertical walls of the said rib.

According to a further feature of the invention, it is possible to arrange in the central rib orifices which are intended to take up over-pressures close to the re-entrant angles existing at the junction of the central guidance rib with the machine-supporting portion of the track.

The following description relating to the accompanying drawings, which are given by way of non-limitative example, will indicate how the invention may be carried into practice.

In the drawings :

FIG. 1 is a view of a cross-section through a first embodiment according to the 10;

FIG. 2 is a view in section taken along the line II--II in FIG. 1;

FIG. 3 is a view of a modification of one detail in FIG. 1.

Referring to FIGS. 1 and 2, here there is shown a machine 1 which cooperates with the machine-supporting portions 2a, 2b and with the guidance walls 2c, 2d of a track, on the one hand by means of cushions 3a, 3b which provide lift, and on the other hand by means of cushions 3c, 3d, which provide guidance, the said track possessing a cross-section, according to the embodiment illustrated in these figures, substantially in the form of an inverted T.

According to the invention, the central rib providing guidance is made up of the walls 2c and 2d, which will preferably be rigid, for example being of metal and substantially parallel, and which between them delimit at least one passage 20 making it possible to link the longitudinal slot 4 (arranged within the structure of the machine) with a space 5 located beneath the machine-supporting portion of track and communicating with the outside surrounding atmosphere.

The walls 2c and 2 d pass down through the machine-supporting portion of track made up of the structures 20a and 20b, which are, for example, composed of concrete. The walls 2c and 2d terminate in upper margins 20c and 20d which are preferably curved over so as to obviate deterioration of the confining walls appertaining to the cushions 3c and 3d.

The hollow central rib should have an unyielding structure able to withstand lateral stresses connected with guidance and, if so required, also the longitudinal stresses due to the propulsion of the machine in the case in which, for example, the central rib constitutes the armature of a linear-motor system of propulsion in which the coil is carried by the machine, or the stresses due to braking if the machine is equipped with jaw-type brakes which squeeze tight against the central guidance rib -- and in the latter case the stresses associated with bilateral compression or crushing as exerted by the jaws. The structural parts are disposed in such a manner as not to offer opposition to flows of fluid towards the space 5. With this aim in view, it may, for example, be possible to arrange diaphragms or dividing plates 6, preferably of metal and provided with relieving holes 7, in a vertical setting at intervals between the walls 2c and 2d and at right angles to the latter, to which they are attached, for example, by means of bolts or rivets (not shown). In order to resist stresses in compression, more especially in the areas subjected to braking action, the diaphragms 6 may, for example, be linked together by means of struts 8 kept substantially parallel to each other and rendered rigid with the walls 2c and 2d by means of bolts or rivets (not shown).

The firm connection of the metal central rib to the machine-supporting portions of track made of concrete is effected, for example, by means of struts 9 which include a threaded part for cooperation with nuts 90 ; in this case, the adjustment of the transverse alignment of the track on its supports 11 is effected by means of devices arranged laterally along the machine-supporting portion of track and the supports, for example screw-jacks 10a, 10b.

It is possible to envisage a case in which, with the struts 9 passing through the central rib without rendering the latter rigid with the machine-supporting portions of track, the connection of the rib to the machine-supporting portions is effected, for example, by means of a system of angle-plates or of angle-bars 12 which include bolts 12a, the said angle-plates being fitted with means to provIde transverse adjustment, such as, for example, screw-actuated devices (not shown) in order to carry out alignment of the track without affecting the concrete structures 20a, 20b.

According to a preferred example, the excess fluid due to leaks from under the cushions providing lift and those providing guidance, adjacently to the junction of the walls 2a, 2b, 2c and 2d, may be vented downward to the space 5 by way of orifices 13 arranged longitudinally at the base of the walls 2c and 2d (figure 2).

It is also possible to envisage the case in which leaks close to the metal rib and taking place from under the cushions 3a and 3b are eliminated, as is described in Guienne et al. U.S. Pat. No. 3,482,528 , by maintaining only the supply 30 of fluid to the guidance cushions 3c and 3d (figure 3). In this case the walls 2c and 2d will not be equipped with venting orifices 13.

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