USRE24272E

USRE24272E - Land vehicle or load-moving device comprising

Info

Publication number: USRE24272E
Authority: US
Priority date: 1952-01-07
Publication date: 1957-02-12
Also published as: GB743997A; FR1078424A; US2714011A

Description

Feb. 12, 1957 w, ALBEE Re. 24,272

LAND VEHICLE OR LOAD-MOVING DEVICE COMPRISING A FLEXIBLE-WALLED, FLUID-CONTAINING,

(PERIPHERALLY-LOADED) ROLLER Original Filed Jan. 7, 1952 5 Sheets-Sheet 1 INVEN TOR.

William 1-1- Albee M 1(- MM ATTORNEY Feb. 12, 1957 w. ALBEE Re. 24,272

. LAND VEHICLE OR LOAD-MOVING DEVICE COMPRISING A FLEXIBLE-WALLED, FLUID-CONTAINING,

(PERIPHERALLY-LOADED) ROLLER Original Fil ed 5 Sheets-Sheet 2 IYVVLWTUR W111i 3111 H All: Be

ATTORNEY Feb. 12, 1557 W. H. ALBEE LAND VEHICLE OR LOAD-MOVING DEVICE COMPRISING A FLEXIBLE-WALLED, FLUID-CONTAINING. v (PERIPHERALLY-LOADED) ROLLER Original Filed Jan. 7, 1952 5 Sheets-Sheet 3 Fig 11 FigJE 5s Fig-1E Lilli INVENTORI William H. AU: EE

ATTORNEY Re. 24,272- EVICE COMPRISING WALLED, FLUID-CONTAINING, I HERALLY-LOADED) ROLLER 1957 w. H. ALBEE LAND VEHICLE 0R LOAD-MOVING D A FLEXIBLE- 5 Sheets-Sheet 4 (PERI P Original Filed Jan. 7, 1952 Fig-1.;

. INVENTOR William H. Al]: E E

ATTORNEY FLUID-CONTAINING. (PERIPHERALLY-LOADED) ROLLER Original Filed Jan. 7, 1952 Feb. 12, 1957 w. H. ALBEE LAND VEHICLE OR LOAD-MOVING DEVICE COMPRISING A FLEXIBLE-WALLED,

5 Sheets-Sheet 5' Fig- E5 INVENTOR Will 1am AUIIE E ATTORNEY United States Patent LAND VEHICLE OR LOAD-MOVING DEVICE COM- PRISING A FLEXIBLE-WALLED, FLUID-CON- TAINING PERIPHERALLY-LOADED] ROLLER William H. Albee, Carmel, Calif.

Original No. 2,714,011, dated July 26, 1955, Serial No. 265,296, January 7, 1952. Application for reissue July 17, 1956, Serial No. 598,730

20 Claims. c1. 130-9 Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions .made by reissue.

This invention relates primarily to a land vehicle or a load-moving device comprising a flexible-walled, fluidcontaining roller for sustaining a load applied to its periphery, as distinguished from a load applied, as in .the case of a wheel, through an axle or the like.

Its chief objects are to provide economy, efiiciency, tconvenience, durability and adaptability in a device of .this type.

More specific objects are to provide a roller of this type having such shape and such structural features as to avoid destructive localization of strains in the wall of :the roller; to provide a roller adapted for facility of :steering of the assembly; to provide improved cushioning of the load; to provide in conjunction with a roller of this type improved means for compelling the roller as a whole to travel at the same speed as that of its load and, relatedly, to provide improved anti-friction means for permitting the porting position, to travel at the necessarily faster speed than that of the load; to provide an improved selfpropelled assembly of this type; to provide a device of this type adapted to be conveniently and eflectively braked; and to provide improved procedure for using a roller of the type above referred to, especially in the matter of steering the assembly and in the matter of.

employing such a roller as a lifting-jack.

The attainment of these objects is of special value in the moving of loads over rough, uneven or rocky ground; or vertically in relation to a rough mine-shaft wall, for example; or over soft or otherwise diflicult terrain, as in the case of sand, swamp, snow or mud; or upon water, with the distensible roller providing a buoyancy means for the load; or over a surface subject to being damaged by other types of load-moving devices; or under conditions such that, as in some military situations, it is desirable to avoid the leaving of an easily discernable track.

Of the accompanying drawings:

Fig. l is a perspective view of a block shaped load and, in their operative relation thereto, a set of rollers embodying my invention in its preferred, simple form for this type of use.

Fig. 2 is a fore-and-aft section of the assembly shown in Fig. 1, except that one of the rollers is broken away and another is shown in elevation.

Fig. 3 is a section, transverse to the direction of travel, of members of the assembly shown in Fig. 1.

Fig. 4 corresponds to Fig. 3 except that it shows an alternative type of roller device.

' Fig. 5 is a front or rear side-elevation of one of the rollers shown in Fig. l as it appears when inflated but not under load.

Fig. 6 is an end elevation of the same.

Fig. 7 is a vertical section illustrating a preparatory stage in the use of one of the rollers as a lifting jack for periphery of the roller, at its load sup Re. 24,272 Reissued Feb. 12 1957 Ice getting the load and the roller in proper relationship for transportation of the load upon and supported by the roller.

Fig. 8 is a like section illustrating a later stage.

Fig. 9 is an elevation of a plurality of the rollers, provided with journals and joined in series by spacer bars connecting their journals.

Fig. 10 is a plan view of the assembly shown in Fig. 9.

Fig. 11 is an elevation showinga preferred method of constructing a roller embodying the invention.

Fig. 12 is a section on line 12-12 of Fig. 11.

Fig. 13 is a diagrammatic fore-and-aft section of one of the rollers provided with a pulling axle, illustrating forces that are present when the roller is pulled by means of the axle.

Fig. 14 is a corresponding section illustrating forces that are present when the roller is peripherally driven.

Fig. 15 is a diagram illustrating factors that are present in the operation of the preferred type of roller and that can be employed for improved steering of the assembly comprising the roller.

Fig. 16 is a diagrammatic section illustrating forces that are present in the supporting of a load under certain conditions.

Figs. 17, 18, and 19 are respectively a perspective view, a fore-and-aft section, and a section transverse to the direction of travel, of a self-propelled assembly comprising a roller of the type under consideration, but with parts of the power means omitted.

Fig. 20 is a foreshortened bottom view of the assembly shown in Figs. 17 to 19.

Fig. 21 is a side elevation of a load-moving device embodying my invention and comprising a series of the rollers.

Fig. 22 corresponds to Fig. 21 except that parts are shown in section.

Fig. 23 is a fragmentary section on line 23-23 of Fig. 20.

Fig. 24 is an assembly somewhat similar to that shown in Figs. 17 to 20.

In Fig. 1 a block-shaped load 1 is supported upon a plurality of rollers or envelopes '3, 3 for movement over rough ground 2 by a driving force applied to the load by hand. In this operation the rollers under the load of course move forward only half as fast as the load, so that rollers in succession are released at the rear of the load, as at 3 and rollers in succession are placed in front of the load, as at 3*, to be moved onto by the load.

The rollers contain so little fluid that roughness of the ground, as at 6, Fig. 2, is compensated for by easy indentation of the flexible and appreciably elastic wall of the roller, without substantial vertical movement of the load, even in the case of obstacles of large size being swallowed by the roller, yet, in spite of the small amount of fluid in each roller, the roller can sustain a heavy load because of the large area of its contact with the under face of the load which is incident to the'low fluid pressure per square inch within the roller.

The load is easily moved because substantially the only frictional resistance to its movement is the internal friction in the wall of the roller that is incident to its flexing as it moves forward in the manner of a selflaying track, and the slight rolling friction of the outer surface of the roller. The load is very effectively cushioned not only because of the roller's easily varying area of contact with the ground and its swallowing of obstructions but, also, because of its easily varying area of contact with the load as an additive cushioning factor.

Each bag is provided with a standard tire-valve and stem 3 or other suitable inlet-outlet valve device, and preferably with a relief valve 3 to prevent a very heavy load, or excessive filling, from bursting the roller. Loss ages-2.

of fluid through the relief valve is compensated by resulting spread of the rollers areas of contact with the load and with the ground.

The 'chief distinction from the prior art, of the rollers shown in Figs. .1, 2, 3, and 6, and of the rollers that preferably are employed in all of the embodiments of the invention that are shown in the-drawings, is that the roller has, in conjunction, the feature. that it is axially elongated, as distinguished from a spherical peripherally loaded roller; the feature that it issmoothly, curvedly and symmetrically-crowned in its load-contacting part, so that upon increase of loading, either static or dynamic, its ground-contact and load-contact areas spread lengthwise of the roller as well as circumferentiall-y of it, for a desirable. load-sustaining and cushioning effect; and the feature that the roller, being made preferably of cordreinforced rubber, hasv sufiicient resilient stretchability of its wall to permit it to stretch along the perimeter of its load-contact area, for example, to relieve radiant compressive stresses in the contact area resulting, from flattening of the crowned-roller wall. Thus thecontactarea can spread without buckling or wrinkling of the wall, which isnto say without destructive localization of strains in the wall. The same of course applies tothe ground-contact area.

The smoothly crowned shape in the load-contacting part of the roller also provides for a new and highly advantageous method of steering, which requires only that the rollers contact area with the ground be shifted toward the right end of the roller, as by rightward tilting ofthe roller, if it is to be steered to the right, for example, whereupon the roller steers-to the right somewhat. in the manner ofv a conical roller traveling upon a flatlsurfa'ce.

The manner in which this efiectis obtained, even when the roller is greatly'flattened by the load, is illustrated in the diagrarnof Fig. 1.5.

There the roller, having the axis of rotation AB,. is represented in outline, asviewed from above, by the fullline ellipsoidal figure, and its straight-travel ground-contact area is represented by the dotted. ellipsoidal figure, within and symmetrical with relation to the full-line figure.

The roller has a greater cross-sectional perimeter at its middle, C, than at either of the extremities, D or E, of the ground-contact area, and yet at each revolution of the roller a relatively long circumferential zone of the wall material. at C must pass the area of ground contact while shorter circumferential zones of wall m-aterialat D and at E. must pass the ground-contact area, with graduation of this factonof course, fromC to E and from C to D.

Thus, taking the right-hand half EEG of the groundcontact area, for example, wall surface in a partof this areaclose toC has to have, in straight travel,abackward ground slippage matched against a forward ground-slippage of ground-contacting surface of the roller closer to E.

In a revolution-of the roller a point on its surface at E, but for its compelled forward slippage, would go only to ground point E; whereas it is compelled to go to ground point E", and a point on the rollers surface at C, but for itscompelled backward slippage, would go to ground point (3 whereas it is compelled to have such backward slippage that it goes only to the ground point C.

The graduation of these mutually compellingslippage factors is represented by the curved line C PE and, in case'of. rightward shifting of the area of ground contact, by the extension B B of the curved line C PE At some position in each half of the ground-contacting portionof the-roller, represented by P in the right-hand half. and by Ointhe left hand half of the diagram, there is: neither forward nor backward ground slippage.

Inthe assumed case of rightward tilting of the :roller for rightward steering, consideringthe roller as moving away fromthe lineZ-W and towardthe line -X--Y, the zone of ground-contact shifts to the right and in this shifting the no-slippage zone P, as itis thought will be clear, migrates to progressively.smaller perimeterpositions nearer the right-hand end of the crowned roller while the no-slippage zone 0 migrates rightwardly to progressively greater-perimeter positions nearer the maximum-perimeter middle of the roller.

With the right-hand no-slippage zone P thus decreasing in perimeter while the no-slippage zone 0 increases in perimeter,.itwill beclear that the zone- 0 travels over the: ground faster than the zone P, which isto say that ther'ollerifollows apath which curves to the right.

One simple way for tilting the roller for steering is simply to shift the'loa'dscenter of gravity to the right or to the left according to the direction of steering desired, asbfy addingaweight to. one side or the other of the load 1 in Fig. 1.

Another simple way is to. apply to the load 1 of Fig. 1, permissibly by hand, a horizontally directed tilting force.

Other ways of. effecting lateral tilting of the roller for steering are made' possible by employment of load-apply,- ing devicesof embodiments of the invention that are here.- inafter described.

This steering capability is at its best when the load is supported by a single one of the rollers, as in Figs; 17 to :20. of the drawings, but is not eliminated by the employment of a plurality of the rollers, abreast or in tandem, under the load.

Fig. 4 shows two rollers abreast of each other, for lateral stability of the load, but connected by an axial tie 3* to keep them from escaping, laterally of their rolling movement, from under the load.

A preferred type of construction for long-wearing, heavy-duty envelopes is illustrated in Figs. 1-1 andl2 and comprises an inner-tube-of elastic rubber 50, over'which is'cemented two end sections of moulded rubber or rubberimpregnatednylon fabric 51 and one or more layers ofrubber-impregnated nylon fabric 52 cut in orange-peel sectionswithcemented laps 53 of sufficient width'to develop'a tensil'e'strength equal to that of the fabric, and over which is cemented one or more layers of rubberimpregnated nylon fabric 54 wound around the loadcarrying, portion of the bag and rubber-cemented thereto, and a. scufi coat or moulded tread of pliable rubber 55 cemented to the entire outside of the bag, thicker over the treadsurfaces; the entire structure is vulcanized into an integral mass by application of proper heat and pressure.

Manyother methods of construction with various materials may be used to'achieve the desired results.

The fluid'mass 4 contained within the envelope 3 may be either gaseous or liquid. For practical purposes, ordinary air isusually used as the gas, and ordinary water as the'liquid although many other gases, such as'COz, and/or many other liquids, may be used.

Gas is preferable as a fluid mass for lightness of weight in handling, and for its. properties of elasticity, compression, and expansion. Gas is usually used where the loads to be floated require-internal pressures within the envelopes of-less than 5' pounds per square inch; also, when more than two envelopes are employed under one object, as in Figure 1,, to take advantage of the expansion and compression properties of gas as the object is moved over uneven ground. Where envelopes are used in the manner of ordinary rollers, Figs. 1 and 2, and are to be inserted in front of a moving object, the envelopes are usually only partially inflated at atmospheric pressure, and develop internal pressure as the load compresses the gas.- Gas will absorb shock better than liquid. Gas is also useful at low temperatures, where ordinary liquids would solidify.

Liquid is preferable as a fluid mass 4 for its property of relative incompre'ssibility. Where very heavy weights are: to be'rnoved, requiring pressures of 5 pounds or more, even up to l00pounds per square inch, liquid will provide an incompressible volume to maintain the required amount of: separation between inside surfaces of the envelope, particularly whenthey are used as rollers,

as described above; whereas gas would compress and allow the envelopes to squash too much in attaining the required pressure. In many cases, both liquid and gas are used together, liquid to limit the squashing of the envelope, and gas for its cushioning and shock-absorbing eflect. Liquid is used to fill envelopes to be used as rollers under water, although enough gas may be added to cause the roller to barely stay at the surface.

To float an object on the envelope, pressure is exerted by the envelope-contained mass of fluid in two principal ways as illustrated in Fig. 16; by direct pressure 56 against the areas of the envelope 3 in contact with the object 1, and by the tensile force 58 transmitted thru the envelope material result-ing from pressure 57 of the fluid 4 against the free Walls of the envelope 3. Where the bottom of :an object is essentially flat and extends beyond the area of contact in all directions, the direct presume is the predominant force of support. Where the area of contact 5 is relatively small, and the envelope extends outward and upwards, as in Figure 16, the tensile force may dominate.

For preliminary use as a jack, for getting the load and the envelope in proper relationship for transportation of the load upon and supported by the envelope, a deflated envelope, Fig. 7, may be inserted in very narrow spaces 7 between an object 1 and the ground 2, and then inflated with suificient fluid 4 (gas and/or liquid) under pressure to float and lift the object the required amount,

' Fig. 8.

The envelopes are suificiently resistant to stretching to contain the fluids under the required operating pressure within predetermined and limited volumes, thereby forcing the contained fluid 4 to support the loads 1. The envelopes are flexible and pliable, which is to say ap preciably elastic, to allow the containers to conform as much as possible to the [irrigularities] irregularities of the surf-ace of the ground 2 and of the supported objects 1, thereby distributing the loads evenly over substantially the entire area 6 of the ground'in contact with the envelopes, and preventing excessive concentration of load at any point of contact.

In the ideal situation, the entire bottom of an object 1 would be floated on one fluid-containing envelope 3 large enough to project from all sides, Figure 3, but since the movement ahead for any appreciable mount, the object 1 would be transported off the top of the fluid mass 4 by frictional contact 5 with that portion of the envelope moving over the top of the fluid mass, another fluid-filled envelope 3 must be ready to receive the load 1, similar to the way in which solid cylindrical rollers are used, Figs. 1 and 2.

The optimum arrangement of an object on more than one envelope in actual use is to provide as many supporting envelopes as can be accommodated for a given area of said object to approach the ideal distribution of load, which would occur if the entire area of the object were supported by 100% surface contact with a single envelope.

The stability of an object floated on envelopes is similar to stability of a similar shape floated on water. Where the center of gravity of the object is comparatively low, it will remain in a stable upright position on the envelope. Where the center of gravity of the object is comparatively high, the object may have a tendency to turn sideways, or capsize." This is because the fluid 4 in the bag 3 is free to move from side to side. In this case, it is advisable to use envelopes paired end to end,

. to achieve stability similar to that developed by two floats in water side by side instead of one, Figure 4.

An improvement to the plain envelope 3 is the addition of a rigid axle 40, Figs. 11 and 17 to 20, inserted in or attached at the longitudinal axis of the envelope to establish an axis of rotation and to aid in controlling the direction of movement of the envelope and the supported load. Such an axle, in this preferred embodiment, is in no sense a load-bearing axle, since'all of the load of the supported object is imposed upon and carried by the loadsupporting surface of the envelope. I

A forward pulling force applied to such an axle of course causes the load-bearing surface of the roller to move forward at approximately twice the linear speed of the axle.

Referring to Fig. 13, which represents a cross-section of an envelope perpendicular to its axle, a force applied on the axle 40 in the direction of the arrow 60 is transmitted thru fabric under tension 61 to the back side 62 of the bag, which pushes contained fluid 4 forward as represented by the arrows 63, creating pressure on the front of the bag 64, forcing bag material intension to rotate forward, 65, in front of the fluid mass, pulling the load-bearing surface 5 of the bag in tension in a forward direction 66. 7

Conversely, a forward force applied tangentially to the lotadbearing surface of the bag will cause the axle tomove at approximately half the speed of the load-bearing surface in the direction of movement.

This is illustrated in Fig. 14. A force 67 applied tangentially to the load-bearing surface 5 of the bag 3 pulls fabric under tension 68 around the fluid mass 4, causing the fluid to move forward 69, because of the contact of the roller with the ground, with the fluid transmitting pressure 70 against the front of the bag, and thru tension 71 in the fabric a forward fotce 72 is applied to the axle.

The axle may also serve as -a means for steering an envelope, or changing its direct-ion of movement. A downward force exerted on one end of the axle, perpendicular to the ground, will cause the axle to tilt toward the ground at said end, and Will cause the roller to tend to pivot around said end in moving.

In some cases, as in Figs. 9 and 10, it is desirable to space a series of envelopes in tandem with their axles parallel and at predetermined distances from each other. Envelopes with axles attached may be spaced with the spacing bars 44 fitted to axles 40 with bearing means 45.

A series of envelopes arranged in tandem may be surrounded fnom end to end by an endless belt 46 for aiding in transporting an object from one envelope to the next. It will be apparent that the axis of rotation of each envelope so employed will travel at one half the speed of the covering belt 46, so that the distance between the axis of rotation of any two envelopes will remain substantially constant, the connecting bars '44 preventing any substantial displacement of any of the rollers as a whole in relation to the others.

Envelopes with or without axles may be used as bearings in raceways with uneven bearing surfaces, in contrast to ordinary solid bearings which require highly finished bearing surfaces. Envelopes used as bearings may be filled with many types of fluid, depending on the functions to be performed.

A simple vehicle unit is illustrated in Figs. 17 to 20, in which a load-supporting roller and its load are compelled to travel at the same speed, and in which the vehicle can be selfipropelled. A load-carrying saddle" frame 73 of box form as shown, or any other form necessary for functioning, is attached to the envelope 3, which is in the usual partially inflated condition; that is, it encloses suflicient fluid 4 to separate the load-carrying portion 5 of the envelope from that portion of the envelope in contact with the ground 6. The frame 73 has journaled therein and encloses saddle rollers 74 which rotate on axles 75 and anti-friction bearings 76. These rollers support an endless belt 77. The belt is wide enough to extend beyond the ends of the envelope 3 and is sufliciently taut to transmit the load from the rollers 74 to the top or load bearing portion 5 of the envelope. Means 78 may be provided to adjust the spacing between rollers 74 to maintain the necessary tautness of the belt 76. The load applied by the object is supported by the frame 73 and thence through the bearings 76 and axles 75 to the belt.

71 and to tlfelo'ad carryingf portion 5? of "the" em velepe and not-"tlifougfi any member serving-as an" axle" of rotation ofthe envelope.- suitabletrea'df patternsfmay' he formed 'in die -load bearing *sui-fziceofthe envelope to minimize slippage both forward and sideways.

An" axle 40"0'1" stubs" of an axle protrude from each end of the envelope 3 to maintain the envelope centered beneath thebelt 77 and frame- 73. The axles-are not loadsupporting axles, and'they may be hollow with holes leading from inside the envelope to' valves in the ends of the axles. Th'eaxlesare held in; position by means of bearings-79 and vertically movable" guides 80 or linkages. The vertically-movable guides 8.0al1ow'the distance between th'e' axle4i] and the belt77 to vary, as illustrated saddle assembly may comprise additional rollers,

or ho'gies 83, Fig; 18, to help distribute the frame load onto the belt "77 and reduce the'belt tension on the main rollers 75.

In theform of the above described preferred embodiment; the vehicle unit has many general fields of application,= including vehicles, dollies, floats, rollers and'conveyors.

In the field of vehicles, this vehicle uni-t takes the place ofthe combined unit represented by a pair of wheels, tires, an axle, and springs.

Such a vehicle as here designated may be used as a single unit, or paired side by sid'e'for greater stability, or in multiples assembled'in tandem. A multiple of envelopes'may be assembled in tandem, as in Figs. 21 and 22, by'means of positioning arms 80 to a single'common load-bearingframe 73, in which case a single belt 77', with one pair of belt ti'ghteners 78,- may serve for all envelo'pes, with'suitable bogie rollers 83 to distribute apon tion of the load to each envelope. In this case, the bellying of the belt between rollers will help to compensate for major irregularities of the ground, as shown in'Figtire-[26122.

One or more unitsmay'also'be pivoted and tilted and thus made to turn in a vehicle.

Power to self propel thevehicle, from a motor not shown, may be applied to one-or more'of the lo'ad' bearing rollers 74; through a sprocket 84, for example, whichWi-ll drive the load supportingsurface 5 ofthe envelopein the direction of movement, through the' belt 77 when' there issuch a beltinte'rposcd" between thesaddle rollers 74; 83 and the ground-contactingroller 3.

In like manner, braking force may be applied to either the rollers 74 or the belt 77.

For'certain'uses of these vehicles it may be desirable'to eliminate the load-bearing belt altogether, as'inFig. 24, in which-case a plurality of closely spaced parallel bogie rollersSd-maybe mounted on axles'75 and-anti frictionjbearings' in fixed position to frame 73; thereby eliminating the necessity for belt tighten'ers. In this case, the'bogies83 rest directly on the load-carrying surface 5 of the" envelope 3.

The invention provides the many advantages that are set forthin the above statement of objects.

.Vehicles supported by these units can transport heavy loads-over irregular andunstable ground, such "as swamps and muske'g, since thelarge area of" contact- With the ground will allowlow pressure. They can also 'transport ex-treri' zely heavyloads over rocky andfirrn ground such as er'rcountered in za desert country, where-"the ground w ill supporthigheripressures; such as pounds or more. per squareainch' withou-tidisplacementt Bodies of water, such as rivers and lakes, may also be lateral direction for steering a 8 negotiated by such vehicles;

envelopes.

Vibration and jars due to travel over rough terrain arereduced to a minimum by the envelopes, especiallyif the envelopes are" filled with air, and aroused-at 10W pres' sures;

In the field of dollies; the vehicle units can be attached fine surfaces Without damages, such as heavy safes over finely finished floors. I I

Used as upside-down dollies, such units as herein dc scribed are particularly adapted-for handling objects having uneven or delicate surfaces, such as polished plate" glass, etc;

Used upside down in series, such units as herein described can be used as conveyors for handling; objects without jarring. In some cases, a continuous-belt'over the top of several units will be'found small objects over the top of a series;

For military bridges large units 'with"specialload-bearing frames may be quickly assembled in tandem into floating bridge sections onshore, takingadvantage ofcover from enemy fire, and then rolled in sections into the Water. In some cases,,bridges could be completely'assembled on shore, the completed bridgeshoved progres= sively out into. the water as assembly progressed; Piers;

for'landings on tidal flats can be'assembled'in similar manner.

In thefield'of roller guides, or bearings, assemblicsas described have many uses, for example, attached to the sidesof mine shaft carriages, they will conform to the irregularities of the. shaft walls, for fixed guides.

Many other'similar uses will be manifest.

As above mentioned, the belt in Figs. 17 to '20 'is'iwide enough to extend beyond the ends of the maximum loadsustainingcontact areas of the envelope or roller 3, and, transversely of'the direction of travel, the belt is held to straight or rectilinear form bythe cylindrical'bogies 83.

There aretwomajor'advantages inherent in this construction, in conjunction with the crownedform of the roller. One is that it has less'fore-and-aft sliding friction: (made manifest in the above discussion of the Fig.

15 diagram) than if'the bogies were omitted'and 'the.belt.

had such stretchability that it would be forced into conformity'with the crowning of the roller. The other of. the two advantages is. that the holding of the belt to rectilinear'form, inthe direction transverse, to the line of travel, results in the load being wholly supported by direct fluid pressure from below, the extremities of'the flattened contact area of the distensible roller being always at some distance inward from the side edges of thebelt, so that there is no sharp bending. of the wall' of the distensible roller such. as occurs at'the positions of the arrows 58 in Fig. 16, or at the side edges of 'therbottom of the loadl'in Fig. 1'.

Both of, these advantages are especially important in the case of heavy loads and 'in-the sure Within the distensible roller.

Further modifications are possible withoutdeparture. from th'escope of the appended claims...

In the appended claims the words axially elongated are used asw-meauing that,-.when the defined -flpid distensibler roller is: distendedv and frceaof a load; its; flexible; wall is, in,- axial section, having, a length, alongzthe rolling-axisofgtheroller, sub stantiallygreaterthan-the maximum .diameterofthegrolherin;forerand-aft section, and-the: word crowned? is: used as meaning that, in the distended and unloaded which will carry a limited pay-load, depending on the relativevolume ofair in the" helpful to carry eliminating the necessity."

case-of high" fluidpres- 9 condition, the fluid-distensible roller is of gradually increasing diameter in directions from its ends. towards its middle, as in the case of a crowned-pulley.

In the case of a self-propelled vehicle (Figs. 17 to 20 and 24) the fluid-containing bag or envelope drives the frame 73 through the links 80, the latter being under longitudinal compression as pusher elements, whereas in the case of a towed vehicle (Figs. 21 and 22, for example) the vehicle drives the bag or envelope, through the links 80, the latter being under longitudinal tension as pulling elements. To cover both types of vehicles, the words horizontal-propulsion means are used in the appended claims with reference to the pushing or pulling links 80 and equivalents thereof.

I claim:

1. A load-moving device comprising an axially elongated, fiexible-walled, fluid-distensible roller for supporting the weight of a load applied to its outer surface for transportation of the load thereon, said roller having, when distended and free of load, a smoothly curved, symmetrically crowned shape in its normal load-contacting and ground-contacting part, and having suflicient resilient stretchability of its wall to permit a load-contacting and ground-contacting part of its wall, in its loadflattened part, to be deformed, without wrinkling of said part, from its crowned form to fiat form, as by loadsustaining ground contact with a flat ground surface.

2. A load-moving device comprising a roller as defined in claim 1, said roller comprising journal means of which the axis is the axis of the roller, and horizontal-propulsion means associated with said journal means for relative rotation of the two.

3. A load-moving device comprising an axially elon gated, flexible-walled, fluid-distensible roller for supporting the weight of a load applied to its outer surface for transportation of the load thereon, said roller comprising journal means of which the axis is the axis of the roller, a load-sustaining structure and revolvable means journaled on said structure and running upon the outer surface of said roller for applying the said weight of the load to the roller, and horizontal-propulsion means having connection to said structure and associated with said journal means for relative rotation of the two for sustaining horizontal propulsion force- 4. A load-moving device comprising an axially elongated, flexible-walled, fluid-distensible roller for supporting a load applied to its outer surface and, in journaled relation thereto, a load-sustaining structure and revolvable means journaled on said structure and running upon the outer surface of said roller for applying the force of the load to the roller.

5. A device as defined in claim 4 in which the recited revolvable means is shaped for load-sustaining contact with said roller, under th force of the load, throughout a part of the surface of the roller that is at least substanas extensive axially as circumferentially of the roller.

6. A device as defined in claim 4 and including fournal means projecting centrally from the ends of the roller respectively and a link hinged to the recited loadsustaining structure and connecting it to the recited journal means.

7. A device as defined in claim 6 and including stop means mounted on the recited load-supporting structure and engageable by the recited link for limiting movement of the axis of the distensible roller away from the recited load-sustaining structure.

8. A load-moving device as defined in claim 4 in which the face of the recited revolvable means that contacts the recited fluid-distensible roller is rectilinear axially of said roller throughout their maximum area of contact with each other.

9. A device as defined in claim 4 including means acting otherwise than through the recited roller for driving the recited revolvable means.

10. A device as defined in'claim 4 in which the recited revolvable means comprises an endless belt in contact with the outer face of the distensible roller.

11. A device as defined in claim 4 in which the recited revolvable means comprises a plurality of loadsustaining rollers in contact with the outer face of the distensible roller.

12. A device as defined in claim 4 in which the recited revolvable means comprises a plurality of loadsustaining rollers in arcuate arrangement, fore-and-aft of the assembly.

13. A device as defined in claim 4 in which the recited revolvable means comprises a set of more than two load-sustaining rollers and an endless belt surrounding the said set of rollers.

14. A device as defined in claim 4 in which the recited distensible roller has, when distended and free of load, a smoothly curved symmetrically crowned shape in its normal load-contacting and ground-contacting part, and has sufiicient resilient stretchability of its wall, in its load-flattened part, to permit a load-contacting and ground-contacting part of its wall to be deformed, without wrinkling of said part, from its crowned form to fiat form, as by load-sustaining ground contact with a flat ground surface.

15. A load-moving device comprising a plurality of axially elongated, flexible-walled, fluid-distensible rollers for supporting a load applied to their outer surfaces, journal means coaxial with said rollers respectively, and tie means connecting the journal means of said plurality of the rollers and holding them with their axes spaced apart whereby the said rollers are disposed in tandem relation.

16. A device as defined in claim 15 including a selflaying track extending about the set of rollers.

17. A vehicle comprising an axially-elongated, flexiblewalled, fluid-distensible roller, said roller having, when distended and free of load, a ground-contacting middle portion throughout which the part of the wall which in tension primarily sustains the distending force of the fluid is of longer-radius curvature lengthwise of the roller than circumferentially of the roller, so that the roller is shaped for load-sustaining contact with a flat ground surface throughout an area that is more extensive axially than circumferentially of the roller, the said wall, throughout the said ground-contacting middle portion, having such easy flexibility that its resistance to flexing is not a substantial factor in localizing pressure of roadway projections against the roller, said vehicle including a load-supporting structure, and journal means and horizontal-propulsion means interposed operatively between said roller and said structure.

18. A vehicle asv defined in claim 17 and including power means for rotating the defined roller in relation to the defined load-supporting structure, so that the defined vehicle is a self-propelled vehicle.

19. A vehicle as defined in claim 17 in which the defined roller is of ellipsoidal shape in its ground-contacting middle portion.

20. A load-moving device comprising an axially-elongated, flexible-walled, fluid-distensible, ground-contacting roller, said roller having, when distended and free of load, a symmetrically crowned shape in its normal ground-contacting part, and having sufficient resilient stretchability of its wall to permit a ground-contacting part of its wall, in its load-flattened part, to be deformed, without wrinkling of said part, from its crowned form to flat form, as by load-sustaining ground contact with a flat ground surface, the wall of the said roller through out its said normal ground-contacting part having such easy flexibility as to permit distribution of the roller's ground-contact pressure evenly over substantially the entire area of its current ground contact.

(References on following page)