US3534689A - Suspended rail way car fluidicly supported - Google Patents

Description

United States Patent [72] Inventor Maurice Barthalon 2,51 1,979 6/1950 Goddard 104/138 78 Avenue Henri Martin, Paris, France 3,106,171 10/1963 Julien n 105/149X [21] Appl. No. 673,818 3,125,964 3/1964 Silvermanm. 104/89 [22] Filed Oct. 9, 1967 3,167,145 l/1965 Mackie.... 212/134 A continuation-impart ofSer. No. 3,225,228 12/1965 Roshala... 310/12 607,184,.lan.4, 1967, abandoned. 3,233,556 2/1966 McDonald 104/89X Patented Oct. 20, 1970 3,381,541 5/1968 Thireau et a1 74/207 [32] Pr-lomy 1966 1966 Primary ExaminerArthur L. La Point [33] gifi 79989 Assistant E.tuminerHoward Beltran [31] v, 2-, AlmrneyYoung and Thompson [54] SUSPENDED RAILWAY CAR FLUIDICLY SUPPORTED 35 Claims35 Drawing Fig5 ABSTRACT: A transporter comprising a continuous beam serving as a track, at least one car movable along said beam [52] US. Cl 104/89, and Suspended th f drive means on said car f motion 104/23, 104/134, 104/155, 105/148, 105/15 long said beam, said transporter comprising a subatmospher- 180/15 198/1, 212/134 10 pressure lifting system for said car, said system comprising [51 1 Int. Cl B611) 3/02, an aipextraction apparatus Carried by Said car, a fi t wall Cap Blb Bloy 3/04 ried by said beam and a second wall carried by said car, said Field of Search 74/207; fi n being locawd above Said second wall during motion 1 14/2355) 89, 3 /143, of said car. sealing members borne by said car limiting the 150; /15; 187/17; 198/177, l;2l2/l34; 1 wall thereof and projecting towards said beam wall, thereby forming between both walls a partially airtight chamber and [56] References C'ted means connecting said chamber to said air-extraction ap- UNITED STATES PATENTS paratus for generating a subatmospheric pressure in said 1,698,482 1/1929 Nicin 180/15 chamber, whereby said car is lifted upwardly.

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Sheet 9 of 12 Patented Oct. 20, 1970 HTTXS- SUSPENDED RAILWAY CAR FLUIDICLY SUPPORTED This invention, which is a continuation-in-part of my application Ser. No. 607,184 filed Jan. 4, i967 and now aban doned, relates to a transporter comprising a continuous beam which serves as a track, at least one car suspended from said beam and displaceable along said track, and drive means for imparting motion to said car or cars. The transporter under consideration is in principle of the overhead type in which the track may be carried on supporting columns, and is primarily intended for the high-speed transportation of passengers.

Taking into account the particularly interesting properties of the transporter, particularly with reference to the ease with which it can be installed and the relatively low power ratings required to drive the cars, this transporter can also be employed as a conveyor system in industrial plants, for example, or as small-scale models which can serve as educational toys.

Vehicles or cars of other types such as those which are supported on air cushions and guided by a track placed under the car body have already been developed, although none has yet been utilized on a large industrial scale for a variety of reasons. In particular, this system involves the construction of a special track and consequently entails high capital expenditure which is justified only on lines which carry a high traffic density over large industrial'areas. However. this type of track is not well suited for the small-radius curves which are essential requirements in such areas. Moreover, when the track is built at ground level, a substantial number of supporting structures are required at the various intersections with other transportation lines which are, of course, particularly numerous in large and highly populated industrial regions. Finally, the general configuration and upwardly directed surface of the track are conducive to the accumulation of snow and consequent interruptions of traffic.

When the track is built on the elevated principle, its eonstruction is not only very costly but presents serious problems in the design of suitable foundations which will carry the substantial weight of the superstructure. In point of fact, the track must be capable of withstanding torsional and bending stresses of a high order as a result of the unstable position of the vehicle or car which is moving over it. However, low transverse moments of inertia, which are due to the cross-sectional configuration of the track, result in low rigidity of this latter. Provision must accordingly be made for a structural assembly which is both cumbersome, unattractive and hardly compatible with modern town-planning requirements.

Transporters of a more suitable design for industrial areas, large towns and suburban districts have also been described in the relevant literature. Such systems essentially consist of cars which are suspended from a beam and which are consequently self-stabilizing, the beam itself being carried on columns. The torsional stress which is exerted on the beam is in this case much lower than in the case previously mentioned. However, this type of transporter has not been developed to any great extent owing to the fact that, up to the present time, coupling bogies are employed between the car and the beam. And the fact remains that these bogies are themselves of substantial weight and support the mass of the car only at some points while nevertheless partially transmitting suspension shocks to the car body, This in turn results in a very appreciable increase in weight both of the car and of the track.

In this design, the. beam is constituted by a rectangular channel-section element in which the bogies are housed, and the underface of which is split in order that the car-body lifting members can be passed through.

The opening which is thus formed in the beam reduces its torsional and bending strength, thereby entailing the need to increase its weight for a given load. The final result is a heavy beam and a high cost of construction of the whole assembly. In many instances, the pressure per unit area which is exerted on the foundations of the support columns and which is imposed by the weight of the beam (despite the fact that this latter is of lighter weight than the track referred-to above) is higher than permissible values in the suburban areas of some large towns, so that a transportation line of this type cannot be built.

It has also been proposed to construct a transporter which offers an improvement over the above-mentioned systems. This improvement consists in suspending the car from a track with interposition of air cushions at a slight excess pressure. As a consequence of this design, the bottom portion of the beam on which the car or vehicle is carried has to be divided into two sections which make a dihedral angle with each other, the air cushions being thus supported on the top faces of each section. The beam has therefore low rigidity as well as being both heavy and costly.

Moreover, the compressed air with which the cushions are supplied is first directed upwardly from the car. and is then caused to follow a U-shaped path through an angle of to be injected onto the track, thereby resulting in further con structional complications and an increase both in weight and capital investment.

The transporter which is contemplated by the invention is intended to overcome the disadvantages attached to the above-mentioned solutions by virtue of the application of a novel lifting means for suspended cars.

The transporter in accordance with the invention is of the type comprising a continuous beam serving as a track from which is suspended at least one car movable along said track and provided with drive means for imparting motion thereto, and is characterized in that it comprises a subatmospheric airpressure lifting system, said system comprising at least one chamber which is provided between the beam and the car body and rendered partially airtight by means of sealing members which permit the displacement of the car, said chamber being connected to an air-extraction apparatus carried by the car and comprising at least one wall carried by the beam which is located above a wall forming part of said car, with the result that the subatmospheric pressure which is maintained within the chamber results in a force having an upward vertical component which tends to lift the car.

By virtue of this combination of means, the torsion couples and impact forces exerted by the car on the beam and conversely are of minimum value and excellent static and dynamic stability of the car can thus be ensured. The invention also permits good distribution of the lifting stress both on the beam and on the suspension members which form part of the car. The structural design of the car body as well as that of the beam can thus be simplified and lightened.

The arrangement of subatmospheric-pressure chambers for the lifting of the vehicle makes it possible to endow the beam with particularly advantageous profiles. The beam can accordingly be provided with walls which are inclined to the vertical whilst the superstructure of the car body has an embracing profile with respect to that of the beam in such a manner as to provide two flanges which are located in vertically overhead relation to said walls of the beam, thereby making it impossible for the car to fall in the event of failure of the air-underpressure lifting force. In this case, steps can be taken to ensure that said beam walls form two flanges which are inclined to the vertical and to provide between said flanges a runway which is thus protected from bad weather conditions and permits the propulsion of the car by applying the car-driving wheels in contact with said runway.

In an alternative version, the beam is a tubular body of revolution and is thus endowed with a high degree of torsional and bending strength.

The car is preferably provided with deformable sealing members which are associated with the beam walls in such a manner as to ensure that any deviation of the car from its normal running position generates a restoring force which tends to bring the car back towards said normal running position.

Construction of self-stabilizing cars is thus made possible. The invention also contemplates a number of different complementary means, among which can be mentioned the appropriate distribution and dimensions of the low-pressure chambers both in length and in width relatively to the car body, a practically independent air extractor for each chamber, pneumatic or mechanical damping members, means for regulating the output of the extractor as a function of the load and the load distribution. These means make it possible to correct the trim of the car and to prevent any extraneous movements such as rolling, pitching, or hunting.

By virtue of the virtually complete absence of contact between the car and the track, and also by virtue of the self stabilizing action which is obtained. the car requires only a small amount of power for its propulsion and affords a high degree of comfort.

In cars controlled by ground effect or air pressure of a known type, difficulties are generally met in ensuring simultaneously that the car is properly guided in the curves and that the car is switched properly from one track to another.

By contrast, my invention comprises the arrangement of a plurality of slide blocks articulated in relation to a given car body which they support. This resolves the problem of keeping to the curve in a very advantageous manner. My invention comprises also a switch system whichis compatible with said arrangement.

A large number of further advantages and properties of the invention will become apparent from the description which follows below.

A number of different embodiments of the invention are shown in the accompanying drawings which are given solely by way of nonlimitative example, and in which:

FIG. 1 is a transverse sectional view taken along line I-l of FIG. 2 and showing a first embodiment of the invention;

FIG. 2 is a fragmentary longitudinal sectional view in side elevation of the embodiment shown in FIG. 1;

FIG. 3 is a fragmentary transverse sectional view taken along line III-III of FIG. 1;

FIG. 4 is a sectional view taken along line lV-IV of FIG. 5 and showing a second embodiment;

FIG. 5 is a view in side elevation of the embodiment of FIG.

FIG. 6 is a sectional view taken along line VI-VI of FIG. 4;

FIG. 7 is a transverse sectional view of a third embodiment, this view being taken along line VII-VII of FIG. 8;

FIG. 8 is a fragmentary longitudinal sectional view taken along line VIII-VIII of FIG. 7;

FIG. 9 is a perspective diagram of the drive members employed in the third embodiment;

FIG. 10 is a detail sectional view on a larger scale and showing a portion of FIG. 7;

FIG. 11 is a simplified transverse sectional view which is similar to FIG. 7 and showing a tunnel track;

FIG. 12 is a diagrammatic plan view on a smaller scale and showing a transporter car in accordance with a fourth embodiment of the invention;

FIG. 13 is a transverse sectional view of an under-pressure chamber in accordance with an improved fifth embodiment;

FIG. 14 is the corresponding longitudinal sectional view which is taken along the line XIV-XIV of FIG. 13;

FIG. 15 is a longitudinal sectional view taken along line XV-XV of FIG. 13;

FIG. 16 is an elevational view on a small scale and showing an alternative embodiment;

FIG. 17 shows in perspective and in transverse cross section a fragment of a particular constructional design of the sealing members;

FIG. 18 shows another alternative form of sealing joint;

FIG. l9is a transverse sectional view of an alternative form of FIG. 1;

FIG. 20 is a plan view of a switch'system of the transporter in one of its end positions;

FIG. 21 is a similar view of the switch system in the other end position;

FIG, 22 is a view in part section taken along the line XX- II-XXIIofFIG.20;

I FIG. 23 is a view in cross section taken along the line XX- III-XXIII of FIG. 21;

FIG. 24 is a plan view in partial section on a larger scale of the switch system in the position shown in FIG. 20 taken along the line XXIV-XXIV of FIG. 22;

FIG. 25 is a cross section on a larger scale of the track, taken along the line XXV-XXV of FIG. 24;

FIG. 26 is a part cross section taken along the line XX- VI-XXVI of FIG. 27 of a track beam and part of a suspended car;

FIG. 27 is a part longitudinal section taken along the line XXVIl-XXVII of FIG. 26;

FIG. 28 is a diagrammatic cross section on a larger scale of part of FIG. 26;

FIG. 29 is a cross section of a tubular track;

FIG. 30 is a view in elevation a'fter sectioning along the line XXX-XXX of FIG. 31 ofa modified car comprising chambers with different subatmosphericpressures g FIG. 31 is the corresponding'plan view after sectioning along the line XXXIXX,XI of FIG. 30'.

FIG. 32 is a pressure graph relating to the apparatus shown in FIGS. 30 and 31;

FIG. 33 is a view in cross section of a modified car provided with a subatm'ospheric-pressure guiding cushion;

FIG. 34 is a view on a larger scale of a detail of FIG. 33 inanother position of the car; and

FIG. 35 is a sectional view of a modified car provided with overpressure guide chambers.

In the embodiment which is illustrated in FIGS. I to 3, the transporter essentially comprises a continuous beam 1 secured to columns 2 which are usually spaced at uniform intervals. The beam 1 serves. as a track for moving vehicles 3, hereinafter referred-to as cars. which are intended in principle to move in the same direction at a givenmoment and over a given section of track.

The structural arrangement of the members referred-to above will now be described in detail. The beam 1, which can be fabricated either of metal or reinforced concrete, is tubular and of approximately rectangular cross section. The beam 1 has a top support panel 4 which serves to increase both the stiffness of the beam and the stability of attachment of this latter to the horizontal arms 5 of the columns 2.

In order to permit the suspension of the car 3 under the requisite conditions of safety, the cross section of the beam 1 is continuous and the underface or bottom panel 6 of the beam 1 is provided on each side with a flange 7, the top face 8 of which is inclined to the horizontal.

The bottom panel 6 of the beam 1 additionally carries two oppositely facing L-section members 31 which extend along said beam and the opposite horizontal flanges 42 of which are separated by a gap 32. The L-section members are symmetrical with respect to the longitudinal midplane A-A of the beam 1. The design function of the L-section members referred-to is to guide and support the car during periods in which this latter is suspended as a result of reduced air pressure; this function will be explained more fully below.

The transporter car 3 comprises a body 9 which, in the example under consideration, is designed for passenger transit service and is accordingly fitted with windows 11 and seats 12. The car body is limited by a roof 13 which is integral with the superstructure of the car. Said superstructure comprises reduced air-pressure lifting elements and two right-angled side flanges I4, said flanges being usually disposed above the flanges 7 and in vertically overhead relation to these latter.

The reduced air-pressure lifting elements are provided for the purpose of maintaining the transporter ear 3 in a position such that said car has a very light weight relative to the beam I. Said pneumatic lifting elements comprise a series of underpressure chambers 15a, 15b (as shown in FIG. 3) which are disposed successively along the longitudinal axis of the car and arranged one at each side in pairs and preferably in symmetrical relation with respect to the longitudinal midplane A-A of the car. The axial length of said low-pressure chambers is preferably greater than the width of the beam. The chambers are limited at the bottom by a wall 19 provided with perforations 21 which'are uniformly spaced over the wall 19 and all of which communicate with a manifold 22 having a cross-sectional area which is substantially greater than the total crosssectional area of said perforations 21 so that these latter practically constitute independent air extractors. The manifold 22 extends from one end of the car to the other so as to terminate in an air-extraction unit which is located at the rear end of the car 3.

In the example herein described, the propulsion of the car 3 is effected by means of an airscrew 24 such as an aircraft propeller. Said airscrew is driven by a motor 25 which may be either of the heat engine type or an electric motor, and can preferably have a variable and reversible pitch with a view to improving the accelerations and decelerations of the car. The airscrew is preferably mounted inside a cylindrical housing 174 in order to reduce propulsion noise and to improve propulsion efficiency.

The motor 25 is also designed to drive the air extractor 10. More specifically, the shaft of the motor 25 carries the rotor 26 of a compressor which constitutes the active element of a rotary air pump, the collector-tank 27 of which is in fact designed to communicate with the manifold 22. Air discharge ducts 28 which are joined to the collector-tank 27 have their openings at the rear end of the car and are directed rearwards at an oblique angle.

The low-pressure chambers a on the one hand and 15!; on

the other hand are separated from each other by transverse partitions 29 which are cut out in steps so as to correspond on each side to the profile of that portion of the beam 1 which is located in oppositely-facing relation thereto. The intermediate space is occupied by a flexible skirt 33 having a grooved edge in the direction at right angles to the leakage flow and formed of a material which affords high resistance to abrasion and which is embedded in the partition wall 29. The skirt 33 thus embraces almost the entire surface of the flange 7, the bottom panel 6 of the beam 1 and the outer lateral surface of the L- section member 31, The end skirts 33a, 33b are outwardly inclined, as shown in FIG. 2. The transverse extremities of the skirt 33 are fixed endwise on seals of distinctly greater thickness and strength. The first seal 34 which is carried by the flange 14 extends over the entire length of the car and extends to the immediate vicinity of the surface 8. The second seal 35 which also extends over the entire length of the car is carried by the perforated wall 19, preferably on rails which are fixed on the perforated wall as will be explained in greater detail in reference to FIGS. 13 and 14. The seal 35 is adapted to cooperate with the underface of the L-section member 31. The seals 34 and 35 are thus common to all of the low-pressure chambers which are located on the same side of the car 3.

The car 3 is additionally provided with at least two carriages 36 each constituted by a body 37 carried by a self orientable shaft 38 which is rotatably mounted in the car superstructure and in the midplane A-A of this latter in such a manner that the body 37 projects above the wall 19 and is received between the two L-section members 31. The body 37 is traversed by a horizontal shaft 39 on which are mounted two wheels 41 preferably fitted with tires, said wheels being thus disposed above the bottom flanges 42 of the L-section members 31.

Chambers such as those designated by the reference numerals 43a and 43b and disposed between the roof 13 and the manifold 22 are provided for the purpose of damping pressure variations and are formed between each pair of associated under- pressure chambers 15a, 15b. Each chamber 43 has an appreciable volume and communicates with the associated under-pressure chamber by way of a duct 44a, 44b of relatively small cross-sectional area. It is apparent that the equipment of the car is completed by all the usual auxiliary components for the transportation of passengers such as those provided for operational control (door control, train-control unit, current collector means if the motor is an electric motor, brakes and particularly brakes designed in the form of brakeshoes (not shown) which are intended to be applied against one of the flanges such as the flange 7 or 31, and so forth).

The relative dimensions between the beam 1 and the different components of the car superstructure are such that, when the car is at rest (or, in other words, when the motor 25 is not in operation and the air extractor 10 is inoperative also, with the result that the chambers 15a, 15b are not at reduced pressure) the car 3 is supported by its wheels 41 on the bottom flanges 42 of the Lsection members 31. In this position, that portion of each of the skirts 33 which is located opposite to the surfaces 8 of the flanges 7 is flattened to a slight extent and a small clearance is thus formed between the panel 6 of the beam 1 and the corresponding portion of each skirt 33. However, there is no contact between the flanges l4 and the flanges 7, the suspension of the car 3 being ensured solely by virtue of the fact that the wheels 41 are applied against the flanges 42.

1f the motor 25 is started up, the reduced pressure which is created by the extractor 10 is transmitted by way of the manifold 22 and perforations 21 to the series of chambers 15a,

15b. Taking account of the fact that the top wall of these chambers forms part of the beam 1 and the bottom wall of the car 3, the hydrostatic thrust which is exerted on the car is no longer balanced and results in a vertical force which tends to lift the car. If the reduced pressure or partial vacuum is sufficient relative to the weight of the car, the car will in fact be lifted and the wheels 41 leave the flanges 42 at the same time as the flanges 14 move away from the flanges 7.

Thus, the car 3 rises vertically in the direction shown by the arrow F and comes into the position of FIG. 1, in which each skirt 33 is disposed with a small but substantially uniform spacing around the corresponding profile of the beam 1 and ancillary components. When the airscrew 24 is set rotating in the propulsion condition, the car 3 is then propelled in the direction G and has practically zero weight and develops virtually no friction forces relatively to the beam 1, with the result that the motive power which is necessary for the propulsion of the car is very moderate.

Taking into account the fact that the exhaust ducts 28 are directed towards the rear, the discharge of air by the extractor 10 produces by reaction a thrust which is favorable to the propulsion of the ear.

The essential advantage of the embodiment under consideration is that the equilibrium which results from the suction action exerted by the under-pressure chambers on the car body 9 (the tendency of such action being to attract the car, as it were, towards the lower surface of the beam 1) is a stable equilibrium under all dynamic conditions of operation which may arise, as will be explained hereinafter.

The reduced pressure within the chambers is maintained by means of the air extractor 10 at the value which is necessary to balance the weight of the car, the function of said air extractor being to compensate for the air which is necessarily admitted by leakage between the beam 1 and the skirts 33, 34 and 35. Under these conditions, if the car 3 moves downwards from the beam at any point, the volume of the corresponding lowpressure chambers increases, thereby reducing the pressure within said chambers and increasing the vertical upward thrust, with a resulting tendency to return the ear to its initial position. This effect is assisted by the flexible seal 34 and skirt 33 which are located opposite to the top surfaces 8 of the flanges 7. In fact, the closing movement of the flanges 14 and flanges 7 has the effect of bringing the above-mentioned seals closer to the surfaces 8. More effective airtightness is thus achieved along the main leakage surface of the chambers, thereby resulting in a correlative increase in the partial vacuum which is maintained within said chambers and consequently in enhanced stability.

In the event of failure of the air extractor 10, the car 3 remains suspended from the beam 1 by virtue of the fact that the wheels 41 bear on the flanges 42. Even in the event that the wheels 41 were to become unserviceable as a result of accident, the flanges 14 would bear directly on the flanges 7 and thus prevent the car 3 from falling. Vertical stability and safety are thus manifestly achieved.

The means which are provided also ensure lateral stability. 1f the car moves in the direction Ya, for example the clearance between the seals 34 and the surface 8 of the flange 7 which is located above the chamber 15a becomes smaller. The volume of this chamber increases, and these two processes result in a pressure drop within the chamber, thereby generating a restoring force in the direction Yb. Concurrently, the pressure has also increased in the chamber 1512 by reason of the withdrawal of the corresponding seal 34 with respect to the surface 8 concerned, taking into account the fact that this surface is inclined to the vertical. A lateral restoring force is thus developed within the chamber 15a in the direction Yb. At the same time, there takes place a reduction in the lateral restoring force within the chamber 15b in the direction Ya.

When a sudden pressure rise takes place within one of the chambers such as 15 a, part of the air passes into the damping chamber 43a through the corresponding duct 44a. This has the effect of reducing the maximum pressure within the cham bers and, when the reduced pressure is restored to its normal design value, the air which is stored within the chamber 43a is restored to the low-pressure chamber 15a. This process therefore reduces the rate at which air is exhausted from chambers 15a, 1512, thereby introducing an element of regulation and damping while preventing oscillations caused by hunting effects. The different characteristics of the chambers 15a, 15b (leakage cross section, volume, etc.) are also calculated to obtain a very low natural frequency in order to prevent resonance effects. The two vertical and horizontal stabilities which have just been demonstrated also result in stability in swinging motion in the direction Z or Z. in fact, a displacement of this type produces an increase in pressure within the chambers which are located on that side of the car, the flange 14 of which moves away from the flange 7 and conversely. There are thus generated two restoring forces in opposite directions, thereby producing a moment of rotation which brings the car back to the position corresponding to its normal trim. The different clearances are in any case adjusted to permit an angular displacement in the direction Z or Z which is limited to :1 as well as to accommodate curves.

Similar effects are contemplated, not about a longitudinal axis of the car but about a transverse axis and producing opposite modifications of pressure between the front chambers 15a, 15b and the symmetrical chambers which are located at the other end of the car, and serve to prevent pitching motion.

Composite movements such as hunting or weaving which break down into elementary movements of the type con sidered can consequently be prevented for the same reasons.

A car of the type under consideration can advantageously be employed for transporting commuters to and from outer suburban areas, the suspension force being very uniformly distributed over the length of the vehicle by virtue of the plurality of adjacent under-pressure chambers which are disposed on each side of the plane of symmetry of said car.

The reduction in weight which is achieved by means of a construction of this type is considerable in comparison with prior art as a result of the elimination of the bogies or suspension shoes and as a result of lightening of the car structure which is made possible by the absence of impacts and by good stress distribution.

In the version of FIGS. 4 to 6, the beam 1 is constituted by the assembly of two cylindrical and coaxial tubes 51, 52 which are held together by means of coupling collars 53, the beam as a whole being constituted by the assembly of a series of sec tions welded together in such a manner as to form a continuous track.

The body 9 of the car 3 is connected by means of suspension ties 54 to slide-blocks 55 which embrace the cylinder 51 over more than one-half and, for example, over two-thirds of its circumference. Each slide-block 55, the length of which, along the axis of the car is distinctly greater than the width of the beam, comprises (as shown in FIG. 4) a cylindrical surface 56, which limits an internal recess, together with flexible skirts 57a, 57b, said skirts being located distinctly above the horizontal diameter of the beam 1. Said beam is provided at the bottom portion thereof with a longitudinal rib 58 which comes substantially in contact with the surface 56 and which constitutes the stator of the linear electric drive motor. The annular space formed between the beam 1 and the surface 56 is thus divided into two chambers 59a, 59b of equal volume when the car is located in its position of normal trim. These chambers are delimited at each end of the slide-block by other flexible seals 61 which project to a slight extent from a rigid support 176 (as shown in FIGS. 4 and 5). Each slide-block 55 is provided with an air extractor 62 which is connected to a suction manifold 63, said manifold being disposed longitudinally and symmetrically with respect to the midplane A-A of the car which coincides with that of the rib 58 when said car is located in its normal trim position. The cross-sectional area of the manifold 63 which is located opposite to the rib 58 is very distinctly smaller than that of the remainder of the manifold 63 so as to provide for the two chambers 59a and 59 two practically independent suction sources.

One of the chambers such as the chamber 5% is partially delimited by a flexible diaphragm 64 which has a large surface area and which is carried at its center by a telescopic damping member 65 which is housed in a cavity 66 of the slide-block.

The upper edges 67. of the slide-block can serve to provide emergency suspension in the event of failure of the vacuum system and are preferably fitted for this purpose with pairs of wheels 68.

The suspension ties 54 in the example under consideration are constituted by flat and slightly flexible Y-shaped armatures or support braces which are attached respectively to the car body 9 and to the slide-block 55 by means of shackles or clamping members 69 and 71. Provision is made between each pair of suspension ties 54 for a transverse coupling comprising two rigid rods 72 which are pivotally coupled at one end to the roof of the car body 9 and at the other end to the slide-block 55, said rods being coupled together by means of a telescopic damping member 73.

The coupling between the car body and the slide-blocks 55 is completed by articulated tie rods 75, 77 which are provided between said slide-blocks and the car body roof 76, the tie rods 77 which are located on the inside being resilient and therefore of variable length and comprising a damping member 78.

in order to effect the propulsion of the car 3, the slideblocks 55 contain the moving portion 79 (as shown in broken lines in FIG. 4) of the linear electric motor (field windings), the stator of which is constituted by the rib 58. There is thus obtained noiseless propulsion as well as powerful braking action when necessary.

The operation is generally similar to that of the first embodiment: when the air extractors 62 are in operation, the slideblocks 55 are lifted as a result of the action of reduced air pressure, with the result that the displacement along the beam, taking into account especially the cylindrical shape of the beam, can take place with very slight friction while imparting to said beam only very limited torsional and bending stresses. Any sudden variation in pressure within the chambers 59a or 5% produces a displacement of the diaphragm 64 and this movement is clamped by the damping member 65, with the result that the car is not subject to any such sudden variations.

The cylindrical shape of the beam 1 additionally permits of free inclination of the slide-blocks and of the car body 9 in the curved sections of track as a function of the centrifugal component, so that the curves do not call for any particular arrangement of the beam, the track being suited for any speed of travel of the car.

The flexible suspension ties 54 also permit the angular play in yaw which is necessary in order that the car can negotiate a curve, even if the slide-blocks 55 are relatively widely spaced. However, in this case, the damping members such as 73 and 78 come into action so as to damp the displacement.

In the event of inclination of the slide-block 55 relatively to the vertical midplane of the beam 1 (under the action of a rolling movement or of a curve), it is found that the sections of the manifold 63 which are located on each side of the rib 58 are modified; the suction becomes more powerful within the chamber which has the larger volume, thereby developing a restoring force which returns the slide-block to the normal trim position and which is added to the forces of gravity which are related to the weight of the car body 9. The car therefore has particularly high swinging stability. Such a solution is well suited for transit service at speeds of over 200 km.p.h. and over distances of the order of 200 to 400 kms.

The embodiment of FIGS. 7 to 10 is characterized in that the beam has a cross section in 'the shape of a star with three arms, namely a vertical arm 83 surmounted by a soleplate 84 which is secured to the column 2 and two lower arms 85 which are symmetrical with respect to each other and preferably inclined to the vertical, thus forming a continuous dihedral surface over the entire length of the track. The flanges 85 are separated by a flat vertical runway 80 which is located at the vertex of the dihedron, extends over the full length of the beam 1 and serves as a wheel track, as will be explained hereinafter.

The car body 9 is coupled to the beam 1 by means of an assembly of slide-blocks 86A, 868 which are provided with the same suspension and propulsion means, but which have different members for coupling said slide-blocks to the car body. Said slide-blocks are provided with a recess having an embracing configuration relatively to the flanges 85, with the result that their profiles have a central trapeze-like projection 88 surmounted by two flanges 89 which are located in overhead relation to the edges of the flanges 85. The two under-pressure chambers 91 which are thus created on each side of the central axis A-A are delimited by two transverse seals 93 of the flexible skirt type which are adapted to cooperate with the lateral faces of the flanges 85, by transverse end seals 94 and by air curtain seals formed in the flanges 89 (as shown in FIG. 10).

The chambers 91 are connected by way of ducts 95 of small relative cross-sectional area to a longitudinal manifold 96 of large cross-sectional area which is formed in the slide-block. If the air extractor is single and placed at the rear of the car as in the case of the first embodiment, the manifolds 96 are preferably interconnected by bellows seals 97.

Airtightness between the flanges 89 and the flanges 85 of the beam 1 is ensured in this case by means of underpressure curtains comprising passageways 98 which are disposed successively along the length of the flanges. These passageways open into a continuous longitudinal gap 98a (as shown in FIG. 10) which is oriented at an oblique angle such that the air stream which is aspirated in the direction of the arrow F 1 when in contact with the flange 85 divides into two streams F F The stream F which is directed outwards prevents the admis sion of the stream F according to a technique which is known per se. In addition, the small clearance between the flange 89 and the flange 85 is another factor which contributes to a limitation of the leakage flow.

The equipment of the flanges 89 is completed by longitudinal emergency shoes 99.

The suspension of the car body 9 from the slide- blocks 86A, 86B is ensured by means of tenons 101A, 1018 formed at the base of said slide-blocks and adapted to engage in mortises 102A, 102B which are fixed on the roof 103 of the car body 9. The tenon 101A is formed by a crossbeam whereas the tenon 10113 has a circular configuration (these configurations being shown diagrammatically in FIG. 8 by means of chain-dotted lines). Similarly, the mortise 102A is rectangular whereas the mortise 10213 is circular. Suitable lateral clearances permit of relative movements of small amplitude.

A system of low-pressure suspension chambers is provided between the male and female coupling members described above, thus forming a two-stage suspension system with the lifting chambers.

To this end, flexible and compressible seals 105A, 105B are disposed between the inner edge of the mortise 102A, 1028 respectively and the top wall of the corresponding tenons 101A and 10113. The shape of the above-mentioned seals is adapted to conform to the shape of the members which carry said seals: the seals A are rectilinear and the seals 1058 are circular. The volumes 106A, 1063 which are reserved between the tenons 101A, 1018 respectively and the roof 103 of the car body are connected by way of ducts 107A, 1078 to the manifold 96 of the slide-blocks.

Provision can advantageously he made for five slide-blocks of the type referred-to above for the suspension of a same car 3 and in order to permit said car to negotiate curves. The oddnumber slide-blocks and the even-number slide-blocks are respectively similar to the slide-blocks 86A, 868.

In the example described, the propulsion of the car is cffected as shown in FIGv 9 by means of drive wheels III which are opposed in pairs, with the result that the car is practically not subject to unstabilizing stress. These wheels are fitted with tires and engaged in recesses 112 provided at the top of the projecting portion 88 of each slide-block. Each wheel III is carried by a vertical shaft 159 which is rotatably mounted in bearings of a fork 113 which is pivoted about a vertical shaft 114 by means of a yoke 115, the shaft 114 being carried by a stationary bearing 116 which is carried by the wall 117 of the recess 112. Each wheel III is urged towards the roller track 80 of the beam 1 by springs 118 which produce action on pistons 119, the heads of which are traversed by the shaft 159. The springs 118 which are associated with damping members (not shown) are housed within cylinders 121 pivotally mounted on pins 122 which are passed through yokes 123, said yokes being also carried by the wall of the recess 112.

The transmission of motion is effected from a drive shaft 124 by means of gears 125 which drive a shaft 126 provided with a universal coupling 127. By means of bevel pinions 128, said shaft 126 drives the shaft 159 of the wheel 111. The shaft 124 is driven by a motor (not shown) which forms part of the corresponding slide-block 86A or 868. Said motor can be either an electric motor, an internal combustion engine, or a gas turbine. In the embodiment described (as shown in FIG. 9) the same shaft 124 drives the two wheels 111. Brakes of types which are known per se and which have not been shown in the drawings (discs, drums and the like) are provided on the wheels 111.

When the air extractor (not shown) is put into operation, the reduced pressure or partial vacuum is transmitted through the manifold 96 to the different chambers 91 and spaces 106A, 1068 which are formed in each slide- block 86A, 86B. Under these conditions, the slide-blocks rise vertically and the same applies to the car body 9 relatively to the tenons 101A or 10113. The car body 9 is thus entirely suspended under the effect of reduced pressure.

If the motors which are provided in the different slideblocks are started up, a translational movement is imparted to the car 3. Taking into account the number of wheels 111, the power of each motor can be of a relatively low order.

By reason of the interposition of the under-pressure suspension chambers 106A, 1068, any shocks, noises and vibrations which would be liable to subject the car body to strain and to cause discomfort to passengers are thus eliminated in a particularly effective manner. In addition, the car body 9 can be designed to effect a slight displacement with respect to the slide-blocks, with the result that curves can very easily be accommodated even when they are of small radius. The replacement of a substantial number of flexible sealing skirts by lowpressure curtains is an interesting feature inasmuch as this last-mentioned means does not entail the use of materials which harden at low temperatures and which have low resistance to abrasion. Moreover, the low-pressure curtains make it possible to reduce to a substantial extent both the leakage flow rates and therefore the extraction power, as well as being both inexpensive to produce and to maintain.

One essential advantage of the embodiment under consideration lies in the fact that the roller track 80 is fully protected against frost and ice by reason of its downwardly directed position in elevation relatively to the downwardly directed flanges 85. Consequently, the adhesion of the wheels 111 to the roller track 80 is excellent. lcicles which might eventually form around the bottom edge of the flanges 85 can readily be removed by providing a heating means such as an electric wire or hot fluid pipe 170 which is precisely located in the vicinity of said edge ofeach flange.

The fact that the propulsion of the car produces a level of noise which is particularly low both for the passengers and in the surrounding atmosphere is of interest, especially in the case of lines which are installed in densely populated areas.

In the event of failure of the air extractor, the car is supported by the emergency shoes 99 on the flanges 85 in a natural manner, with the result that no accident need be feared.

During operation, the dihedral configuration of the active portion of the beam 1 ensures excellent transverse stability. It is also found that the system is self-stabilizing with respect to rotational movements about axes which are parallel to the axis of the track and that stability with respect to hunting or weaving movements is also ensured.

The embodiment of the type referred-to above is particularly well suited to suburban transit service in cold countries, for the reasons given above.

All the versions described in the foregoing can evidently be designed for operation in tunnels instead of being suspended from beams so as to constitute an aerial track. However, the embodiment of FIGS. 7 to 10 is particularly suitable for the in stallation of underground tracks, as is apparent from FIG. 1 1.

In this case, the flanges 85 of the beam are secured to the roof 131 of the tunnel 132. It will be noted that the small space formed between the flanges 89 and the underface 133 of the roof 131 reduces the laminar leakage flow towards the underpressure chamber.

In another version which is contemplated by the invention, the under-pressure chambers have a perimeter in the shape of a concave polygon, the sides of which are constituted by segments of circles. A design of this type is shown in FIG. 12, in which there can be seen at 135 the flexible four-sided curvilinear skirts which determine the contour of the under-pressure chambers 136 which are mounted on the roof 137 of the car body 9. Taking into account the fact that the pressure forces are exerted in an inward direction, the contour is selfstabilizing. The skirts 135 can comprise a plurality of parallel walls 171 (as shown in FIG. 17), thereby increasing their overall strength without reducing their vertical flexibility. As is the case with all the other flexible skirts hereinabove described, said skirts can have toothed ends 181 forming labyrinth seals at right angles to the air flow so as to reduce leakage.

As in the case of those which have previously been described, the previous embodiment can advantageously be combined with a particular arrangement of the under-pressure chambers which is shown in FIGS. 13 to 15, whereby the reduced pressure or partial vacuum within each chamber can be adjusted according to the applied load. In this version, the skirts 135 are secured to the periphery of metallic structural members 141 provided at intervals with runner wheels 183. The structural members 141 are carried by plungers 142 which are slidably mounted inside cylinders 143 formed in the superstructure of the car and disposed at intervals along the structural member 141, as shown in FIG. 14. Each plunger 142 is urged upwards by a spring 144 fitted in the cylinder 143. Said cylinder is adapted to communicate with the lowpressure chamber 136 by way of ducts 146 provided with adjustable shutoff valves 147. Flexible pleated skirts 172 provide continuity between the structural members 141 and the car roof 137.

Under these conditions, it is apparent that, when the roof 137 of the car superstructure moves away from the underface 148 of the beam 1, the springs 144 expand and maintain the skirts 135 in the vicinity of the surface 148, any continuous contact being prevented by the interposition of runner wheels 133 which impose a lower limit on the distance between the skirt 135 and the beam 148.

According to one improvement of the system under consideration, the plungers 142 are designed for operation in such a manner as to ensure positive control of the skirts against the wall 148, the distance between said skirts and the car body being correspondingly greater as the roof 137 of the car superstructure tends to move further away from said wall 148. This result is obtained by arranging the plungers 142 after the fashion ofjacks by virtue ofa communication duct 151 which may, for example, be of triangular cross section and which serves to provide a connection between the cylinders 143 and the outer air.

The superstructure of the car body additionally comprises position detectors 152 which are slidably mounted in suitable recesses and fitted with runner wheels 153 enabling them to run over the wall 148. The position detectors 152, which are urged towards the wall 148 by springs 154 housed in chambers 155 are provided with apertures 156 having a suitable shape and a cross section corresponding to that of the ducts 151. A mechanical coupling (not shown) is provided between the members 141 and 152 so as to close the regulating loop in accordance with a method which is known per se in conventional servo motors.

When the car is located in its normal trim position, the apertures 156 are displaced in height relatively to the duct 151 (as shown in FIGS. 13 and 15), with the result that the cross-sectional area of passage provided for the admission of the outer air to the cylinder 143 has an intermediate value; the pressure which exists in said cylinder is therefore slightly higher than that which prevails within the chamber 136, but is nevertheless lower than atmospheric pressure.

On the other hand, if the car 3 moves away from the wall 148, the position detectors 152 move vertically in the direction of the arrow K (as shown in FIG, 15) and the apertures 156 tend to become coaxial with the ducts 151. The leakage flow accordingly increases to an appreciable extent,

with the result that the pressure which is developed within the cylinders 143 exceeds the pressure developed within the chamber 136 to an appreciable extent. Consequently, the plungers 142 are forcibly thrust towards the beam, thereby bringing the skirts 135 closer to the wall 148 and substantially increasing airtightness. The pressure thereupon drops within the chamber 136 under the action of the air extractor and the upward vertical thrust consequently increases, with the result that the car is restored to its normal trim. Steps can also be taken to ensure that the displacement of the rod 152, or alternatively the pressure which prevails within the cylinder 143 and the values of which depend on the load of the car, control respectively by means of link-rod systems or ducts such as the duct 145 a unit for regulating the rate of flow of air which is extracted. Such a unit may, for example, be a throttle valve or unit for regulating the extractor motor.

In this version as in the previous versions, steps can also be taken to ensure that the under-pressure chamber 136 communicates with the air extractor (not shown) by way of a duct which is preferably designed to project from the roof 157. The distance to which said duct 175 projects is such that, in the normal trim position, the cross-sectional area of passage between the top rim 157 of the duct 175 and the opposite surface 148 is sufficient to produce a limited throttling of the airflow. If the car rises above its normal trim position, the free passage becomes smaller, throttling of the airflow takes place at the inlet of the duct 175 and air suction is then prevented. The pressure consequently rises within the chamber 136, with the result that the car tends to return downwards to its normal position. If, on the contrary, the car moves downwards, the cross-sectional area of passage towards the duct 175 increases, the pressure within the chamber 136 drops and the car then has a tendency to move upwards to its normal position.

The flexible seals 93 of the car which is contemplated in FIG. 7 and following can advantageously be designed as shown in FIG. 18 and comprise a flexible wall 166 of arcuate cross-sectional configuration and provided with a projecting sealing skirt 167. The wall 166 which is provided with bellows 182 constitutes an air chamber 168. Said air chamber is supplied through a channel 169 from a cavity such as the cylinder 143 of FIG. 13. and the pressure developed within said cavity increases with the distance between the car and the track or. in other words, increases with the load. The flexible wall 166 thus expands progressively as the load increases, thereby bringing the skirt 167 closer to the wall of the beam with which it cooperates.

Another alternative form which is more especially related to the first version of the invention is shown diagrammatically in FIG. 19. In this embodiment, the wheels 41 and their supports are not essential to the operation of the transporter and are ac cordingly dispensed with, whilst the L-section members 31 of the beam 1 are joined together in such a manner as to form a single rib 160, the seals 35 being also joined together to form a single seal 161 located in the central plane of the car. The centering of the car is effected by the development of transverse pneumatic forces in the manner which has been described earlier, the air extraction circuit being provided with air-throttling ducts 164 which operate in the same manner as the ducts 175 contemplated in FIG. 13.

Provision is also made for runner wheels 162 having vertical axles and adapted to come into contact with either one side or the other of the central rib in the event of too great a transverse displacement. The wheels 162 are carried by flanges, the underfaces of which are provided with shoes 163.

Each chamber 15a, 15b comprises a separate air extractor 173a, 173b for the purpose of preventing any variation in pressure within the chamber from affecting the pressure within the other chambers.

in the event of accidental stoppage of the air extractor, the emergency support would then be provided directly by means of the shoes 163 which come into contact with the flanges of the rib 160. If necessary, the shoes 163 could be replaced by runner wheels having horizontal axles and permitting the propulsion of the car even if the air extractor is inoperative. Braking action can be ensured by means of the reversiblepitch airscrew and/or by clamping jaws (not shown) which are applied against a flange or rib such as 160 and, in the event of emergency, by stoppage of the extractors, thereby causing the shoes 163 to rub with strong friction against the rib 160.

Satisfactory operation of a transporter according to the invention has been noted under the following conditions obtained by means of two experimental assemblies, in the first of which the air extractor carried out simultaneously the suspension of the car relatively to a cylindrical beam of revolution and the propulsion of the car resulting from the reaction produced by a rearward discharge of air. In the second assembly, propulsion was effected by means of an airscrew which was driven by an electric motor.

Prototype I Prototype II It is apparent that the forward speed is particularly high when taking into account the useful load and the power of the driving source.

It will be understood that this invention is not limited to the modes of construction hereinabove described and that a large number of alternative forms may be contemplated. In particular, the different technical means (airtightness, propulsion, connection between the car body and the slide-blocks and so forth) which have been described in connection with a given solution can be adopted in another solution and conversely.

Furthermore. although reference has been made essentially to the displacement of one car along the beam, it will be apparent that the invention makes it possible without any difficulty to construct trains by coupling a series of cars 3A, 38. as can be seen from FIG. 16. These cars can be coupled together by means of communication bellows 158 in which are housed in particular the coupling gear. In this case, some cars may be provided only with air extractors for ensuring suspension of the car whereas other cars are equipped with both air extractors and propulsion motors. Trains of any length can thus be built which are capable oftaking curves of short radius with the greatest of ease.

Provision can also be made in the beam, and especially in the flanges, for heating means consisting of tubes through which is circulated a heating fluid or consisting of built-in electric heater elements of the resistance type, the design function of said heating means being to permit deicing under cold weather conditions.

One of the objects of the present invention is also to solve the problem of correct switching of a car suspended by subatmospheric-pressure lifting system between a plurality of elevated tracks.

Accordingly the transporter further includes a switch system comprising two sections of track extending in different directions and movable between two aligned portions of straight track and a portion of branch track.

The sections are preferably mounted on a carriage movable on supports at which the track portions terminate and this carriage carries at least one stop member which closes the track which has been interrupted by the displacement of the movable section of track, leaving a certain clearance for connection to the atmosphere.

Still greater safety can be obtained for the transporter by arranging for one of the walls of the subatmospheric-pressure chamber ensuring the lifting of the vehicle to have apertures connecting to atmosphere and fitted with obturators which are brought automatically into the open position when the track portion is interrupted by a switching operation. It is thus possible to stop the lifting action on each car approaching the stop member and thus ensure a powerful braking effect.

Referring to FIGS. 20 to 23, there can be seen two portions 10 and lb of a main track for a subatmospherie-pressure chamber transporter system of the kind contemplated by my invention, the track in the example described consisting of a tubular beam.

The portions 1a, 1b belong to a straight track and are in line one with the other, and they are separated by a switch system which will be described below and which a portion 10 of a branch track abuts.

The switch system, the object of which is to cause the cars suspended from the portion 1a to pass at will towards the portions lb or 10, essentially comprises two sections of tubular track, one straight section, 201, and one curved section 202, of the same cross section as the portions 10, lb and 1c. The two sections 201, 202 are joined together at their ends by crossmembers 203, 204, the assembly forming a rigid carriage 205 which can be moved transversely with respect to the straight track portions 1a, lb.

For this purpose the switch system comprises crossbeams 206, 207 on which carriage 205 can move and which are supported by pillars 208, 209 in such a way as to constitute gantries. The beams 206, 207 have roller tracks 211, 212 bounded by stops 213, 214, which paths support rollers 215, 216, carried by the crossmembers 203, 204.

The beams 206, 207 likewise serve to support the track portions 10, 1b and 10 which are connected to them by ribs 217a, 2l7b and 2l7c.

Similarly the track sections 201, 202 of the carriage 205 are connected to the crossmembers 203, 204 by ribs 218, 219a

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