US2880849A - Collapsible and extensible conveyor and loader - Google Patents

Description

April 7, 1959 J. cRAGGs ET AL 2,880,849

coLLAPsIBLE AND ExTENsIBLD coNvEYoR AND LOADER Filed Nov. 30, 1956 3 Shee'cs-SheefI l INVENTORASl I1, Cra ya' M'zza COLLAPSIBLE AND EXTENSIBLE CoNvEYoR AND LOADER Filed Nov. zo, 195e J. CRAGGS ET AL April 7, 1959 3 Sheets-Sheet 2 llvVElx/Tolw Jaep gli April 7, 1959 J. cRAGGs ET AL 2,880,849

COLLAPSIBLE AND EXTENSIBLE CONVEYOR AND LOADER Filed NOV. 30, 1956 5 Sheets-Sheet 3 INVENTOR Jos NEYS

United States Patent O 'COLLAPSIBLE AND EXTENSIBLE CONVEYOR AND LOADER This invention relates to a portable extensible and retractable loader having a self aligning and self troughing endless conveyor, and more particularly to a portable conveyor and loader of the type referred to wherein the endless conveyor adjusts itself automatically to load variations and positions.

It is an object of this invention to provide an extensible and retractable loader which is readily extensible and elevated to any position within its limits, wherein the self aligning and self troughing endless conveyor operates at any point of extension or elevation of the loader.

Another object of this invention is the provision of an extensible and retractable loader having a plurality of flexibly mounted belt supporting and troughing roller assemblies.

A further object of this invention is the provision of flexible and yieldable side rails for mounting the belt troughing roller assemblies on the loader.

An additional object of this invention is the provision of an extensible vand retractable loader having a pair of telescoping frames each having laterally spaced flexible strands for supporting the troughing roller assemblies.

Another object of this invention is the provision of an extensible and retractable loader having exible and yieldable side rails and flexible troughing roller assemblies mounted on such side rail, where the side rails are flexible and yieldable relative to each other.

Another object of this invention is the provision of an extensible and retractable loader having rope side rails and flexible troughing assemblies which reduce spillage of materials being loaded thereby.

A further object of this invention is the provision of an extensible and retractable loader having a self troughing conveyor having inherent load pocketing properties.

A general object of the present invention is to provide a loader having the following .advantages over the conventional loaders constructed with rigid framing and hav- Aing rigid troughing roller assemblies spanning the rigid f framing:

(a) Lower first costs and maintenance, lighter weight, and longer life;

(b) The ability to be easily and quickly extended and elevated;

(c) Inherent self-alignment, that is, the taut, flexible support strands being trained along parallel -courses maintain the troughing roller assemblies in alignment;

(d) Impact absorption of a very high order, approaching that of a trampoline, so that it is virtually impossible for a sudden high loading to destroy or over stress the flexible framing and troughing roller assemblies;

(e) Improved load retention, spillage of material being loaded being drastically reduced;

(f) Troughing roller assemblies which automatically operate to train thebelt properly; and

(g) Troughing roller assemblies which automatically tend to center the load on the belt.

A primary object is to provide a loader having a belt -.conveyor.comprisingexiblestrand means .trainable along i fice a course and being transversely flexible at a place where connected to a transversely exible belt carrying means or troughing roller assembly for concurrent flexing movements of the strand means and of the belt carrying means under loads applied to the latter to thereby absorb impact by the cumulative flexing of the flexible carrying means and of the flexible strand means. In a preferred form, disclosed herein, the cumulative flexing is achieved -by suspending the flexible troughing roller assembly at a location on the strand means which is spaced or remote from the place of support of the strand means relative to the ground.

An important feature, in the nature of a basic building block of the present invention, is that `a pair of flexible strands are trained along spaced parallel courses on the loader, and a flexible troughing roller assembly is suspended across the strands. The reach of the belt is, in turn, supported on the roller assembly.

Another important feature, in connection with the combination set forth in the previous paragraph is that the roller assembly is connected to the strands at locations spaced towardly or rearwardly from the strand supports of the loader. This provides two-way freedom of movement (vertical and horizontal) for the ends of the vroller assembly, resulting in advantages d through g above.

Another object is the provision of an improved troughing roller assembly in a loader structure, particularly adapted for suspension across flexible strand side frames,

-which has means permitting freedom of motion at each end in a -direction parallel to the belt, to automatically train the belt by urging it to run along the center of the troughing assemblies.

Another object is the provision of an improved trough- .ing roller assembly in a loader having a rope side frametype conveyor, which is flexible in at least a vertical plane and which is bodily shiftable in a horizontal plane to automatically vary the troughing contour under varying loads, and to vary its horizontal orientation automatically as needed to maintain the belt reach properly trained.

Yet another object is` the provision of an improved troughing roller assembly in a loader having a rope side frame-type conveyor in which the ends of the troughing assembly are firmly locked to the ropes to utilize their torsional resistance in supporting the belt as well as in relating the up and down movement ofadjacent roller assemblies under Varying loads.

Still another object is the provision of a loader having ay rope side frame-type conveyor in which impact on the troughing roller assemblies under a moving load is minimized by telegraphing, through the ropes and ahead of the load, a force which depresses the roller assemblies in anticipation of the load carried by the belt.

Another object is the provisions of a loader having a rope side frame-type conveyor in which impact is minimized by use of a troughing roller assembly which has the characteristic of an improved angle of lif resulting from the ability of the roller assembly to displace itself in a downward and forward direction, as a load moves over it. Thus, the load is lifted through a smaller angle than is the case for conventional, rigidly mounted troughing roller assemblies.

A further object is the provision of a loader having a rope side frame-type conveyor in which spillage is greatly reduced as the result of a troughing assembly which increases both in volume and in load-retaining angle with increasing loads.

Another object is the provision of a loader having a rope side frame-type conveyor in which the edge portions of the load-caddying run automatically pockets a -load to hold it in place with minimum spillage.-

Another object yis the provision of a loader having a conveyor in which the belt is so flexibly supported that a load is never subjected tolarge impacts. This results from the favorable load-deflection characteristics of the troughing roller assemblies, which themselves are freely articulated for deflection in a vertical plane and are suspended across flexible strands at locations where the laterally spacedstrands are free to deflect vertically and laterally inward.

A further objec-t is the provision ofa 'loader having a rope side frame-type conveyor in which impact absorption characteristics are improved by the vability of the ropes to shift lengthwise, `in limited amounts, toward ya section of the conveyor on which the load is i11- creasing, and shift away from a section in which the load is decreasing. For example, as a load is fed onto a moving, empty belt, the laterally spaced flexible sup- :port strands will shift from the rear end of the conveyor Atoward the forward end of the moving loader, and as the tail end of the load passes over the belt, the strands will shift in a rearward direction behind the receding rload.

In conventional loaders having rigid side frame conveyors, which support the troughing roller assemblies at `fixed levels, loads are carried yby the belt in an uneven path, up over a roller assembly and then down to the 'bottom of the catenary of the belt between roller assemblies. In the loaders of the present invention, it is a further object to provide some catenary sag to the -b'elt conveying reach between the troughing roller asisenibli'es so as to provide a path of load movement which would be uneven, las in conventional loaders, except for the concurrent ilexing movement of the roller "assemblies and the strands or ropes; for the feed-in of 'strands orropes toward the loaded portion of the belt, and for the improved angle of lift of the belt; allof these 'combining tto moderate the uneven path lof the -load hr'riovernertt as'the load is carried by the belt lalong the supporting structure. In fact, this tiexible load support- 'ing structure tranquilizes a moving load so eifectively 'that la large lump, constituting in effect almost a point load, can be carried from one end of the extended loader to the other with so little bobbing movement that is not lperceptible except on close study.

'Other objects and important features of the invention willfbe apparent Afrom a study of the following specification Ytaken lwith the accompanying drawings, which :together describe and illustrate a preferred embodiment -of"t`he invention. Other embodiments may be suggested to those having the benefits of the teachings herein,and such other embodiments are intended to be reserved to the extent they fall within the scope and spirit of the appended claims.

In't'he drawings:

"'Fig. vl is a top plan view of the loader in retracted position;

Fig. 2 is a side elevation of same;

Figs 3 'and 3A, takentogether, comprisea longitudinal vertical 'sectional vview of the loader in extended and elevated position;

K'Fig. 4 is Van enlarged fragmentary cross-sectional view "taken substantially on the line V4--4 of `Fig. 2, looking 'inthe direction of the arrows;

Fig. 5 is an lenlarged fragmentary cross-sectional view substantially on'thefline 5-5 of Fig. 3;

Fig. 6 is an enlarged fragmentary cross-sectional view substantially on the-line 6--6 of Fig. 3, and n Fig. V7 'is a detailed fragmentary view of the roller assembly suspension means.

Attention is now directed to Figs. land-2 of the drawing wherein there is 4shown an extensible -retractable loader zindicated generally by the reference numeral 10. The-loader 10 includesa main body frame or chassis 12 which comprises apai'r of laterally spaced longitudinally extending vertically disposed side frame structures 14, 16 each having rear support plates 18 and lower support plates 20 rigidly secured thereto. The side frame structures 14, 16 each have the corresponding rear support plates 18 carrying an axle 22 which has ground engaging wheels 24, 26 rotatably mounted thereon. The other end portions of each frame section 14, 16 may be supported on a pair of jacks or other suitable type support- ing elements 28, 30 which may be removed -or retracted when the loader is to be transported. The side frame structures 14, 16 are rigidly secured together Vby longitudinally spaced transversely extending cross members 32, 34 and r36. At the forward end of each of the side frames 14, 16 there is rigidly secured an angle member 40 which permits a main conveyor frame 44 to be relatively vertically pivoted at the forward end thereof to the forward end of the main body frame 12 for vertical pivotal movements of the rear end of the main conveyor frame 44 in relation to the main body frame 12 by bolts 46, 48 passing through and mounted in the angle members 40. The main yconveyor frame 44 comprises laterally spaced longitudinally extending vertically disposed side members 50, 52 each including a pair of vertically spaced angle iron members held in spaced relation by a plurality of vertically disposed angle members 54 rigidly secured to the respective angle iron members. The vertical members 54 are provided with similar horizontal inwardly extending angle members 55 for a purpose later to appear.

The front and rear portions ofthe side frame members S0 and 52 are each supported by plates, not illustrated, 'but which are similar to the plates 18 and 20 `of the main body frame 12, and transversely extending longitudinally spaced cross beams 56.

An extension or secondary conveyor frame 58 is slidably mounted for longitudinal movement `in the main conveyor frame 44. The extension conveyor frame '58 comprises laterally spaced longitudinally extending vertically disposed side frame members 60, 62 constructed in a manner similar to the construction described for side frame members 50 and 52 of the main conveyor frame 44. The extension conveyor frame 58 is braced by longitudinally spaced transversely extending cross beams 64 and diagonal beams 66. At the rear end of lthe extension conveyor frame 58 there is a pair of uprights 68, 70 secured to the side frames 60, 62, respectively, and rigidly braced by beams 74, 76, respectively. At the rear end of the main frame 44 there is a similar ybeam V82 and inclined braces 84, 86, which are rigidly secured to the side frame structures 50, 52. The function of the two upright frame structures will be set forth in detail hereinafter.

Each of the side frame structures 1'4, 16; 50, 52; 60, 62, so far described, is of substantially lazy U-shape in `cross section. This specific cross sectional .form provides track or guide means for roller means later to be described. Such roller means provide for the extensibility and retractability of the respective frame structures 'relative to 'each other.

A pair of frame arms 88, constructed similarly to the side frame structures 14, 16; 50, 52; 60, 62 are pivoted-on a shaft 92 which is mounted in the upper ends of the upright vbeams 78, 80 at the rear ends thereof and supported by the cross beam 82, and are provided at their forward ends with flanged rollers v96, 98, respectively, riding on the lower guide surfaces or tracks 94 of the 'side frame members 14 and 16 of the main frame 12. Near the forward end of the main body frame 12 and slightly in advance of the forward ends of the arms 88, 90, when in retracted position, there is a shaft having a crank 102 thereon. A pair of Vsprockets 104, 106 are xed on the shaft 100. Near the rear of the main body frame 12 are mounted a .pair of sprockets 108, rotatable on a shaft 112 carried by theside 'frame structure 114, r16. An endless sprocketfchainf116 is trained over the sprockets 104 and 108, and a similar endless' sprocket chain 118 is trained over the sprockets 106 and 110. The chains 116 and 4118 comprise traction means for the arms 88 and 90 and are suitably connected respectively to the forward ends of said arms. It will be apparent from the above that counterclockwise rotation of the shaft 100 will move the upper reaches of the chains 116 and 118 rearwardly causing forward ends f the arms 88, 90 to move rearwardly to elevate the rear ends thereof which are rotatably mounted on the shaft 92 to cause the main conveyor frame 44 to be elevated and pivotal about bolts 46, 48.

A shaft 120 is mounted near the forward end of the main conveyor frame 44 and is provided with a crank 122. A pair of sprockets 124, 126 is mounted on the shaft 120. A further pair of sprockets 128, 130 is rotatably mounted on a shaft 132 near the end of the conveyor frame 44. A sprocket chain 134 has one end thereof attached as at 138 to the forward end of the side frame member 60 of the extensible frame 58. The chain 134 extends forwardly about the sprocket 124 and thence rearwardly to the lower portion of the sprocket 128, about the sprocket 128 and thence forwardly to the forward end of the side frame member 60, where the other end of the chain 34 is attached as at 140. A similar chain 142 is trained in a like manner about the sprockets 126 and 130 and is likewise attached in a similar manner, by its end, to the forward end of the side frame 62 of the extensible frame 58. Rotation of the shaft 120 in a counterclockwise direction will extend or pull the extensible frame 58 rearwardly into the extended portion, while clockwise rotation will retract the frame 58 from its extended portion to the normal retracted position thereof. In the extending and retracting movement, the extensible frame 58 rides on and is guided by rollers 144, 146 rotatably mounted at the rear of the main conveyor frame 44 and on rollers 148, 150 rotatably mounted on the forward end of the extensible frame 58. The rollers 144, 146 ride on the guide surface 151 of side frame members 60, 62, see Fig. 4, and the rollers 148, 150 ride on the guide surfaces 153 on the side frame members 50, 52, see Fig. 5.

The specific relationship of the pivotal means with respect to each other and to the cables will be described in more detail hereinafter.

A pair of strengthening cables 152 and 154 for supporting the extension conveyor frame 58 in extended position are each attached at one end to the cross beam '72. The support cable 152 is trained forwardly over a pulley rotatably mounted near the upper end of the upright 78, and then downwardly and under a further pulley 158 rotatably mounted adjacent the lower end of the upright 78 thence forwardly and is attached in taut condition at the forward end of the extensible frame 58 as at 160, note Fig. 3. The support cable 154 is trained over pulleys 162 and 164, respectively, in a manner like that described for the cable 152, it being also attached in taut condition to the forward end of the extensible frame 58. The support cables 152 and 154 stabilize the extensible frame 58 in its forward and rearward movements.

A pair of troughing roller assembly supporting flexible cables 166 and 168 are mounted in the main conveyor frame 44 as by passing through openings 170 in the horizontally disposed inwardly extending angle members 5 of the vertical angle members 54, the ends of the cable 166 being attached as at 172 and 174, respectively, in angle members 55 at the rear and forward ends of the main conveyor frame 44. The cable 168 is likewise attached to corresponding angle members 55 at 176 and 178. Similar cables 180, 182 are mounted in suitable openings 183 in the vertical angle bars 61 forming part of the side frame 60, 62. The cable 180 is anchored at 184 to the brace 74 and at 186 in an angle member 6'1 at the forward end of the side frame 60. The cable 182 is similarly anchored at 188 in the brce 76 and at a suitable point, not shown, in an angle bar 61 at the forward end of the extensible frame 58.

Each troughing roller assembly 187 consists of a plurality of idler rollers which can vary in number according to the width of the belt. In this case three idler rollers are shown, each assembly including a pair of inclined or wing rollers 189 and 191, and a center or load supporting roller 190. Each of the rollers is arranged to turn upon a dead shaft 194 and the adjacent ends of the shafts 194 are doubly articulately interconnected at 200 by links so that the rollers 189, 190 and 191 are freely movable relative to each other in a vertical plane common to the longitudinal axis of the rollers and shafts to accommodate the variations in a load on the conveying reach 208.

The wing rollers 189 and 191 are connected respectively at 201 to the adjacent flexible support cables 166, 168, and 180, 182 by means of a link 204 connected by a pin 205 to the end of the adjacent respective dead shaft 194 and by a pin 207 passing through the ear 203 of a U-shaped clamp 202, the bight of whichclosely grips the cable 166, 168 or 180, 182, as the case may be, with the clamp retained by a pin 209 passing through a suitable opening therein.

The clamps 202 are longitudinally spaced in relation to and positioned at intervals between the bars 55 and the angle members 61, preferably two clamps between each pair of longitudinally `spaced cable supporting positions defined by the bars 55 and the angle members 61. The double articulated connection 201 permits relative shifting movement in a substantially horizontal plane which is normal to the vertical plane of relative vertical movement between the rollers 189, 190 and 191 and common to the longitudinal axis of the shafts 194 between the ends of the troughing roller assemblies 187 and the respective support cables 166, 168 and 180, 1.82. This shifting movement of the ends of the roller assemblies 187 in relation to the respective support cables permits self training of the belt, as will appear in more detail hereinafter.

The troughing roller assemblies 187 are placed in a position normal to the longitudinal axis of the conveying reach 208 as can be determined by the eye. However, such placement may be at angles other than right angles to the cables 166, 168 and 180, 182 and to the longitudinal axis of the conveying reach 208 without disturbing the self training feature of the troughing roller assemblies 187.

Each troughing roller assembly 187 is free to shift in a horizontal plane in directions to correct to a small degree any misalignment of the conveying reach of a belt. It has been found that the training effect is primarily caused by the center load supporting roller 190, and in actual test conditions the center load supporting roller 190 has been found to be hunting back and forth at each of its ends a distance of from M3 to 'G". This swing or hunting ,of the ends of the load supporting roller 190 shifts the belt at that point in a direction towards the center of the conveyor. The troughing roller assemblies are commonly mounted at distances approximately five feet apart, and the sum total effect of many such troughing roller assemblies is equal to or greater than the effect of a conventional training roller located every two hundred feet.

The troughing roller assemblies 187 thus prevents an accumulative misalignment of the belt by making a correction of any misalignment at each assembly.

The swivel connection 201 at the outermost ends of each troughing roller assembly 187 is rigid against movement in a vertical plane, as has been described, and by reason of the clamping action afforded by the clamp 202 and the locking pin 209, a load carried by the conveying reach 208 will be transmitted into the side supporting flexible cables 166, 168 and 180, 182, and the torsionaL,

7 resistance thereof will prevent unduey sagging of the assemblybyI reason of such load. In fact, it has been observed that the twisting of the side supporting flexible strands by reason of such load will be transmitted into the next. adjacent troughing roller assembly, so that it will deform in a vertical plane an amount which is related to the deformation in a vertical plane at an adjacent loaded troughing roller assembly, the net effect being to provide smooth travel of the load over the troughing roller assemblies.

In order to limit the torsional strain to which the cables 166, 168 and 180, 182 are subject under load the bights of the U-shaped clamps 202 will be preferably small-enough togrip the strand firmly so. as to limit the strain to that portion of the strand between the adjacent supporting positions -of the cables. By this construction it is possible to. regulate the hardness or the softness of the ride of material on the conveying reach by changing the initialy tension placed on the support strands.

It will be observed, of course, that the interconnections 200iof the center load supporting roller 190 and the inclinedwing rollers 189 and 191 are such as to permit the movement of the rollers with respect to each other in a vertical plane but are rigid against relative horizontal movement. In other words, the, rollers may orient themselves with respect to each other in accordance with the load thereat, limited only by the tension in and the torsional resistance of supporting cables 166, 168 and 180, 182.

The structure disclosed herein presents some unusual phenomenawhich are strikingly unusual considering the simplicity of the assemblies making up the total corn-bination of our loader. A number of these phenomena have been recited in the objects of this invention, and conceivably could not be apparent nor understood without explanation of phenomena taking place in actual-use of the structuredescribed and claimed herein.

IOne of the important features of the invention is the fact that the structure embraced thereby tends to sense the oncoming of a load on the belt ofthe loader. Stated -conversely, the load on the belt in eiect telegraphs the oncoming thereof so as to cause portions of the structure remote from vthe load to adapt itself-'to the oncoming load.

Referring now to the drawings, the phenomena existing in the laterally spaced support cables 166, 168 and 180, 182 and also in the troughing roller assemblies 187 whichv span the support strands will now be explained. A load placed onthe lower end -ofthe conveying reach 208 and moving from the right to the left in Fig. 3 in al direction towards the `first or lowerrnost troughing roller assembly 187` causes the assembly to be displaced downward. The force transmitted to the troughing roller assembly 187 bythe load causes its deflection downward causing the support cables 180, 1S2to be displaced downward and inward.

The displacement or deformation of the supporting cables 180, 182 will increase as the load comes closer to the first troughing roller assembly 187. Thisincreasing displacement in a downward and inward direction of the support cables 180, 182 will cause a displacement of the support strandsI at the next troughing assembly 187, the second onefrom the right as seen in Fig. 3. This latter troughing rollerassembly 187 will likewise, be displaced downwardly, and as the load moves past the first troughing roller assembly and to positions closer to the second assembly, the second assembly will displace increasing amounts in accordance with the proximity of the load. Obviously, the deflection of the support cables 180 and 182 will increase to a maximum as the load is directly above the assembly, decreasing from such maximums as theload moves away from the assembly.

The phenomena have been described with reference to what-,might be considered al point load, and in addition to thedescribed displacement of the troughing assembly and the support cables, there is what `may be called a pocket- 8. ing eiectwhere the belt partly encloses the load by inward displacement of the support strands.

The phenomena described may be` likened to the casting of ashadow` by the load or the-telegraphing thereof' of its imminence to the next proximate troughing roller assembly. This telegraphing or shadow effect causes the exible cable strands to yield as has been described in accordance with the then loading on the conveyor of the loader or theimminent loading thereon; so the roller assemblies actually begin to duck down to receive a load before the load, or even its shadow effect, reaches it, thereby minimizing shock or impact as the load'passes over the roller assembly.

The foregoing phenomena of the flexible strands and' the troughing roller assemblies also result in what mightv be'described-as a smooth ride of the material moving on the conveyor of the-loader'. =Heretofore, where rigid side framing was employed with rigid troughing assemblies, the sag vertically of the conveying reach between the troughinglassemblies cause-d the loads on the belt, particularly spotl loads, to bump over the assembly. On the other handit has been found, in operations employing a loader having a.conveyor of the type disclosed herein the ride` is so smooth that spillage is-materially minimized.

It may be noted that a load-changes the troughing contour ofthe conveying-reach, to increase the load carrying capacity; This change in contour of the conveying reach pockets the increased load, as heretofore explained,- and greatly reduced spillage.

It has'also been found that the mounting of troughing roller` assemblies 187 in the manner as shown in Figs. 4` to.7, inclusive, makes use of the torsional resistancel of the flexible strands. It will be remembered that the U-shaped clamps 202 are held tightlyto they flexible strands. by. means of the pins-209, the swivel connection 201.: at. thexlinks 264 being rigid ina vertical plane but free ,toswivelor shift in a horizontal plane.

rIhe connections 281 are rigid against relative move-v ment in averticalplane, and the wing rollers are of rigid construction and actas cantilever arms between the interconnection1200 andtheconnections 201 in transmittingV the force created by a. loadat the assemblies 187 to the cables through the effective cantilevers ofthe wing roller Shafts194 and the connections 201.

At the forward end of the main-conveyor frame 44, the upper reach 208 of an endless beltconveyor Zilli-passes over asupporting and driving roller 210 and travels.rear.. Wardly to the roller 212 atthe rearof the extension framel 58, where it nowv becomes the lowermost reachl of thebelt 206, travelling downwardly and rearwardly underl the idle roller 216 rotatably mounted on the lower ends of the braces 74 and 76. The belt 206 thence passes to the roller 218 .rotatably mounted on the forward end'ofi' the extension frame 58 about the roller 218, making a turn to travel rearwardly as an intermediate reach 220.E The length of this reach 220 will vary, as will the others mentioned, according to the extension or retraction of the extension frame 58- relative to the main conveyorv frame-44. Passingrearwardly theintermediate reach 220 e bends about'the roller 222 rotatably mounted on the shaft 132 and makes a 180 turn to become the return reach 224 back to the drive roller 210.

The conveyor loader of thisinvention may be operated` at any elevation within the limits of the arms 83, 90, and.

at any extension within the limits of the length of the. extension frame 58. At extreme extensions, the outer or rearward end of the extension frame is stabilizedandl supported by the cables 152, 154.

Power to drive the conveyorrbelt 206 may be applied.

by means of a belt 226 passing about a pulley 228 on, the shaft 211 ofthe roller 210. The belt 226 `may be-2 9 able power source or prime mover and reduction gear may be used in lieu thereof.

Having now described our invention and its mode of operation, we claim:

-1. A loader assembly comprising a rigid main frame structure, a rigid extensible frame structure telescopically mounted on said main frame structure for movement thereon between an extended and a retracted position, flexible strand means trained along each of said frame structures, said strand means being secured adjacent the end portions thereof to the respective frame structure with an intermediate portion of each strand means being transversely deflectable, an elongated belt carrying anti-friction means adapted to support a conveying reach of a belt for movement thereacross, said anti-friction means being exible in a direction transverse to the length thereof while varying the spacing between the ends thereof, and connecting means between said intermediate portions of the strand means and the respective ends of said antifriction means permitting limited freedom of movement of said ends toward and away from one another for flexing movements of said intermediate portions of the strand means and said anti-friction means under loads applied to said anti-friction means, said flexible strand means, flexible anti-friction means and connecting means constituting a structure which is yieldable to absorb impact by the iiexing of said deectable intermediate portions of the strand means and of said flexible anti-friction means.

2. A loader assembly comprising a rigid main frame structure, a rigid extensible frame structure telescopically mounted on said main frame structure for movement thereon between an extended and a retracted position, an endless belt trained around both of the frame structures, each of said rigid frame structures having a plurality of flexible strands trained along generally parallel courses, each of said strands being secured adjacent the end portions thereof to the respective rigid frame structure, supporting means on each of said rigid frame structures for supporting the respective strands, and an elongated troughing roller assembly being ilexible in a direction transverse to the length thereof and connected to said strands at locations spaced from said supporting means, said belt having the load carrying reach thereof running along and being supported by the troughing roller assembly, said flexible strand and flexible troughing roller assembly being effective to yieldably support loads applied to and carried by the belt.

3. A loader assembly comprising a rigid main frame structure, a rigid extensible frame structure telescopically mounted on said main frame structure for movement thereon between an extended and a retracted position, at least one pair of exible strands for each frame structure, said strands each having the end portions thereof secured to the respective frame structure with each pair of strands being trained along generally parallel courses, supporting means for each pair of strands carried by each of said frame structures and effective to maintain the respective strands spaced a iixed distance apart at theV respective supporting means but relatively free for transverse movement relative to one another at a location remote from said supporting means, a troughing roller assembly extending between each pair of strands adapted to support a conveying reach of a belt trained between both of said structures comprising a series of roller-supporting members, an interconnection between adjacent of said members enabling said adjacent members to move relative to one another about said interconnection in a plane normal to said strands at said remote location, a pair of brackets, each of said brackets supported at a respective one of said strands at said remote location, and connections between said roller supporting members at opposite ends of said series and respective on'es of said brackets, said connections being rigid against substantial relative movement between said roller-supporting members and the respective brackets in said plane normal to the strands at said remote location whereby a load ori said troughing roller assembly can be supported at least in part by said rigid connections in the direction of said plane.

4. A loader assembly comprising a rigid main frame structure, a rigid extensible frame structure telescopically mounted on said main frame structure for movement thereon between an extended and a retracted position, each of said frame structures having a pair of laterally spaced flexible strands, said strands each being secured adjacent the end portions thereof to the respective frame structure, at least one elongated troughing assembly extending transversely between each pairV of said strands adapted to support a conveying reach of a belt trained between both of said structures, said troughing assembly being ilexible in a plane normal to the strands to vary the spacing between the ends thereof, said troughing assembly having belt engaging elements which are movable relative to one another in a plane normal to said strands, said ends of the troughing assembly being secured to said flexible strands at locations where said strands are relatively movable to vary the spacing therebetween,

whereby loads applied to said troughing assembly arel absorbed by ilexing of the flexible strands and the troughing assembly.

5. A loader assembly comprising a rigid main frame structure, a rigid extensible frame structure telescopicallyv mounted on said main frame structure for movement thereon between an extended and a retracted position, said frame structures each having a plurality of flexible strands, said strands each having the end portions thereof secured to the respective frame structure, a plurality of supporting means on each of said frame structures for supporting the respective flexible strands thereon in pairs which 'are disposed along generally parallel courses, said supporting means being positioned at intervals along said respective strands and effective to maintain the respective strands at a predetermined spacing at said intervals, said strands of each pair being transversely deflectable toward and away fro-m one another at positions intermediate said supporting means within limits determined by the tension in the respective strands, an articulated troughing roller assembly connected across each pair of said strands at each of said intermediate positions, each of said roller assemblies comprising a plurality of shafts freely pivotally interconnected on a pivotal axis parallel to said strands, the end shafts of each assembly being connected to said strands by freely movable double articulated connections permitting swinging of each roller assembly as a unit in a plane parallel to said strands, a roller rotatably journalled on each shaft adapted to support a load-carrying reach of a belt, whereby a suddenly increasing load on the roller assemblies may be cushioned against impact by the exi-ng of the roller assemblies and of the strands at' said intermediate positions where the roller assemblies are connected thereto.

6. A loader assembly' comprising a rigid main frame structure,v a rigid extensible frame structure telescopically mounted on said main frame structure for movement thereon between an extended and a retracted position, an endless belt trained around both of the frame structures, a pair of laterally spaced ilexible strands on each frame structure, said strands each having the end portions thereof secured to the respective frame structure, support means carried by each frame structure for supporting the respective strands thereon, said support means including means holding each of said strands against rotation relative to said support means, an elongated troughing roller assembly transversely exible along the length thereof and extending transversely between said strands and supporting the conveying reach of the belt, said troughing roller assembly being spaced along said strands from said support means to provide twistable lengths of said strands between said support means and said troughing roller assembly, a clamp connection between each of saidiffexible strands and a. corresponding end of the said roller assembly, whereby downward swingingmovement of each end" of said troughing roller assembly about the respective strandis resisted by. twisting of at least one of sjaidftwistable. lengths ,of ystrands to thereby limit the transverse ilexing movement of said troughing roller assembly so the load on said troughing roller assembly is supported` atleastinpart by the torsional resistance of said flexible strands.

7'. A loader assembly comprisinga rigid main frame structure, a rigid extensible frame. structure telescopically mounted on said main frame structure for movement th'ereon between an extended and a retracted position, apair of laterally spaced flexible strands carried by each of said frame structures, each of said strands being secured adjacent the end portions thereof to the respective frame structure, at least one elongated troughing roller assembly extending transversely between each pair of said strands adapted to support a conveying reach of a belt trained between both of said structures, each of said troughing` roller assemblies being flexible along the longitudinal axis thereof in a generally vertical direction, and a connection between each end of the respective troughing roller assemblies and the respective adjacent flexible strand, each of said strands being free at said connections to deect generally vertically and horizontally in accordance with the loadon said troughing roller assembly, said flexible strand.

and flexible troughing roller assemblies being yieldable to absorblimpact loads on the troughing roller assemblies;

8. A loader assembly comprising a rigid main frameframe structure, said strands each having the end portionsthereof secured to the respective frame structure, support means on each of said frame structures for` supporting said strands, first and second troughing roller assemblies extending transversely between and attached to each pairv of saidstrands for supporting the conveying reach of theA belt, each of said troughing roller assemblies being transversely flexible along the length thereof, said troughing roller assemblies being spaced from each other along each oflthe respective strands to provide a twistable length ofl each respective strand therebetween, each troughing roller assembly including end portions, each of said end portions being clamped to one of the respective strands against rotation relative thereto, whereby ilexing of the first troughing roller assembly under a coming load on the conveyor belt swings the end portions of the first troughing roller assembly in directions to twist said twistable lengths ofthe respective strands to swing. theA end` portions of the second troughingroller assembly indirections' to increase the troughing volume and side wall retaining angle of the conveyor belt at said second troughing roller assembly before the load reaches it.

9. A- loadery assembly comprising a rigid main frame structure, a rigidextensible frame structure telescopically mounted on said main frame structure for movement thereon between an extended and a retracted position, an endless conveyor belt trained around both of the frame structures, `a pair of laterally spaced, substantially horizontal, llexible strands for each frame structure, each-of said strands havingY the end portions thereof secured to` the respective frame structure, at least one elongatedy troughing Lroller assembly extending transversely betweenl each pair of strands and supporting th'e conveying reach.

from; oneV another, said connections restraining swinging ,l movement Yin a substantially vertical 4plane of each end of said" roller assembly relative toy the respective -strand-v to which it is connectedbut permitting greater relative 'movement therebetween in a substantially horizontal plane whereby a load ont. the rollerA assembly is supported'at least in part by the torsional resistanceofrsaidv flexible strands while said roller assembly isfree to shiftin said substantially horizontal plane to maintain said conveyor beltcenteredthereon.

l0',A A loader assembly comprising a rigid mainframestructurea rigid extensible frame structure telescopically mounted on said main frame structure for movement thereon" between an extended and `a retracted position, an-

endless belt trained around both of the frame structures', a pair of flexible strand means for each frame structure,

each of said strand means being secured adjacent the end portions thereof to the respective frame structure, troughing roller assemblies for supporting the load carrying reach of the belt, each of said roller assemblies comprising a plurality of rollers, means interconnecting saidrollers for ilexing movement thereof in a substantially vertical direction and for shiftingmovernent thereof as a:

unit in a substantially horizontal direction, a bracket for connecting each of the roller assemblies to one pair of the exible strand means, and a connection betweeneach bracket and an end of the respective roller assembly mounted on said main frame structure for movementY thereon ybetween an extended-and a retracted position, anv endless belt trained around both of the frame structures,l a pair of flexible strand means for each frame structure,.

each of said strand means being secured adjacent the end portions thereof to the respective frame structure, troughing roller assemblies carried by each pair of strand means and supporting the load carrying reach of the belt,.

each troughing roller assembly comprising a seriesof elongated roller-supporting members arranged in endto-end relationship along a longitudinal axis, a bracket at each end of said series of members connecting' the respective ends thereof to the respective strand means, and an. interconnection between adjacent' members providingk for freely pivotal relative movement of said membersy about a first transverse axis which transversely intersects said longitudinal axis, said interconnection beingy relatively rigid aaginst relative movement in the direction of said first transverse axis, each of said brackets havingy a double pivotal connection with a respective end member of said series providing for freely shiftable movement of said end member relative to said'bracket about spaced, parallel second and third transverse axes, respectively,

which transversely intersect said longitudinal axis, saidconnection being relatively rigid against relative movement in the direction ofsaid second and third transverseY axes, and said first axis intersectingy said longitudinal axis in a direction which is substantially at right angles to the direction of the second and third axes.

12. A loader assembly comprising a rigid main frame structure, a rigid extensible frame structure telescopically mounted on said main frame structure for movement thereon between an extended and a retracted position a pair of laterally spaced flexible strands for each frameassembly beingk flexible along the longitudinal axis there-- of in a vertical direction and comprisingv a series ofroller-supportin'g members having vertically flexible interconnections therebetween and a connection between the 13 A roller-supporting member at each end of the troughin roller assembly and the respective adjacent flexible strand, each of said roller-supporting members at each end of the troughing roller assembly constituting a Vertically rigid cantilever member extending from the respective strand inward to the rst interconnection, each of the respective strands being free at said connections to deflect vertically and horizontally in accordance with a load on the troughing roller assembly whereby flexing movements of the respective strands at said connections and of the troughing roller assembly Iare effective to absorb impact load on the troughing roller assembly, and whereby further flexing of the troughing roller assembly at each interconnection is resisted at least in part by the vertical rigidity of the cantilever members.

l 13. A loader assembly comprising a rigid main frame structure, 'a rigid extensible frame structure telescopically mounted on said main frame structure for movement thereon between an extended and a retracted position, an endless belt trained around both of the frame structures, a pair of flexible strand means for each frame structure, each of said strand means being secured adjacent the end portions thereof to the respective frame structure, troughing assemblies secured to each pair of the flexible strand means by mounting means, the troughing assemblies supporting the load carrying reach of the belt, each of said troughing assemblies comprising a plurality of anti-'friction members disposed along a longitudinal axis, means interconnecting said anti-friction members along said axis for individual relative movement of each member in relation to each other in one plane and unitary movement of the anti-friction members in another plane which is disposed substantially normal to said one plane and common with said axis, and a connecting means connecting the respective mounting means to each end of the respective troughing assemblies for relative movement of each mounting means` in relation to the respective end of said troughing assembly in said -another plane, said connecting means being relatively rigid against relative movement of each mounting means in relation to the respective ends of said troughing assembly in said one plane whereby as the belt passes over the anti-friction members in a direction substantially parallel to the one plane the belt will be supported at least in part in the direction of another plane by the relative rigid connection between the mounting means and the respective ends of the troughing assembly.

v 14. A loader assembly comprising a Wheel mounted chassis, a rigid main frame structure pivotally mounted at one end thereof adjacent the forward end of the chassis and extending rearwardly therefrom with the other end of the rigid main frame being free and movable in a substantially vertical plane relative to the chassis, means for moving the -free end in the vertical plane including a pair of spaced apart arms each having one end pivotal to the main frame adjacent the free end thereof with the other end of each arm engaging the chassis, a rigid extensible frame structure telescopically mounted to the free end of said main frame structure -for sliding movement thereon between an extended and a retracted position, means for moving said extensible frame structure between said positions, flexible strand means trained along each of the frame structures, said strand means each being secured adjacent the end portions thereof to the respective frame structure supporting means on each of the frame structures supporting said flexible strand means, elongated belt carrying anti-friction means adapted to support a conveying reach of a belt trained about both of the frame structures, said anti-friction means being flexible in a direction transverse to the length thereof and connecting means connecting the anti-friction means to the respective strand means remote from said supporting means for flexing movements of the respective strand means and anti-friction means under loads applied to said anti-friction means.

l5. A loader assembly comprising a wheel mounted chassis, a rigid main frame structure pivotally mounted at one end thereof adjacent the forward end of the chassis and extending rearwardly therefrom with the other end of the rigid main frame being free and movable in a substantially vertical plane relative to the chassis, means for moving the free end in the vertical plane including a pair of spaced apart arms each having one end pivotal to the main frame adjacent the free end thereof with the other free end of each arm engaging the chassis, a rigid extensible frame structure telescopically mounted to the free end of said main frame structure for sliding movement thereon between an extended and retracted position, means for moving said extensible frame structure between said positions, a single endless belt trained around both of the frame structures, a pair of flexible strands on each of said frame structures, each of said strands being secured adjacent the end portions thereof to the respective frame structure, means carried by each of said frame structures for supporting said strands thereon and to limit relative transverse movement of each respective pair of strands at one location yet providing greater relative transverse movement at another location spaced along the strands from said one location, and a troughing roller assembly flexible at least in a plane normal to the respective strands and suspended across each pair of strands at another location thereon, said belt having the load carrying reach thereof running along and being supported by the troughing roller assemblies, each pair of flexible strands and the respective flexible troughing roller assembly constituting yieldable support means effective to absorb loads applied to the belt.

16. A loader assembly comprising a Wheel mounted chassis, a rigid main frame structure pivotally mounted at one end thereof adjacent the forward end of the chassis `and extending rearwardly therefrom with the other end of the rigid main frame being free and movable in a substantially vertical plane relative to the chassis, means for moving the free end in the vertical plane including a pair of spaced apart arms each having one end pivotal to the main frame adjacent the free end thereof with the other free end of each arm engaging the chassis, a rigid extensible frame structure telescopically mounted to the free end of said main frame structure for sliding movement thereon between an extended and retracted position, means for moving said extensible frame structure between said positions, a pair of llexible strands carried by each of said frame structures, each pair of strands being secured adjacent the end portions thereof to the respective frame structure and trained along generally parallel courses with the adjacent portions thereof being transversely deectable to vary the spacing between said portions under loads applied transversely thereto, troughing means adapted to support a conveying reach of a belt trained about both of the frame structures, said troughing means being transversely flexible along the length thereof to vary the spacing between the ends thereof when dellected, said troughing means having belt engaging elements which are adjustable relative to one another in a plane normal to the strands, and connecting means connecting said troughing means to said portions of the respective pairs of flexible strands whereby flexing movements of the said portions of said respective flexible strands and of said troughing means are effective to support loads applied to said troughing means.

17. A loader assembly comprising a wheel mounted chassis, a rigid main frame structure pivotally mounted at one end thereof adjacent the forward end of the chassis and extending rearwardly therefrom with the other end of the rigid main frame being free and movable in a substantially vertical plane relative to the chassis, means for moving the free end in the vertical plane including a pair of spaced apart arms each having one end pivotal to the main frame adjacent the free end thereof with the other free end of each arm engaging the chassis,

arigid extensible :frame: structure"` telescopically mountedl tothe free end of'said'main framestructure' for sliding: movement thereonfbetween an* extended and retracted'y position,.m'eans for moving: said extensible frame" structure between'said'positions, a single endless belt'traned around both= of.' the. frame structures; aI pair of-y flexible strands tensionedtalong generally'parallel-coursesifor eachv frame structure, lsaidfstrands each having the-end portions*l thereof securedito the respectiveffralmestructure; a plurality of snpportingcmeans oir-each of" s'a'idframe structures for supportingthe respective'exible'f strands thereon, said supporting means benig positioned" at'intervals along said respective strands and effective to maintain the respective strands at -a predetermined spacing, each pair of strands being transversely deflectable' to vary the spacing therebetween at positions intermediate the supporting means within limits determined by the tensions in said respective strands, an articulated troughing roller assembly connected across each pair of said respective strands ati each of said intermediate positions, each articulated troughing roller assembly comprising a series of shafts,

each having a roller rotatably journalled thereon and supporting the loadcarrying reach of the belt, adjacent shafts being pivotally interconnected in end-to-end relationship for relative flexing movement about a pivotal axis running longitudinally of said strands, bracket means clamped to each of said respective strands at said intermediate positions, and swivel connections between said bracketmeans and the respective ends of said series of shafts for shifting said articulated troughing roller assemblies in a plane parallel to the respective strands, responsive to movement of an off-center co-nveying reach of the' belt thereacross, to aposition to restrain said reach toward the center of the respective strands.

18. A loader assembly comprising a wheel mounted chassis, a rigid main frame structure pivotally mounted at one end thereof adjacent the forward end of the chassis andextending rearwardly therefrom with the other end ofthe rigid main frame being free and movable in a substantially.l vertical plane relative to the chassis, means for moving the free end in the vertical plane including a pair of spaced apart arms each having one end pivotal to the mainframe adjacent the free end'thereof with the other free end of each arm engaging the chassis, a rigid extensible frame structure telescopically mounted to the free end of said main frame structure for sliding movement thereon between-an extended and retracted position, means for moving said extensible frame structure between' said positions, a pair of flexible strands tensioned` along generally parallel courses on each of said frame structures, said strands each having the end portions thereofy secured to the respective frame structure, supporting means on each of said frame structures for supporting the respective pair of strands thereon, said supporting means being effective to maintain the respective strands ata predetermined spacing at said supporting means, the respective pair of strands being transversely deflectable to vary the spacing therebetween at positions remote from said supporting means within-limits determined by the tension in said strands and the proximity of said supportingk means, at least one roller assembly comprising aseries of shafts each having a roller rotatably journalled thereon adapted to support a load carrying reach ofy a conveyor belt, adjacent shafts being pivotallyinterconnected in end-to-end relationship for articulating movement about a pivotal axis running longitudinally of the frame structures and connecting means on each of the respective strands at said position remotefrom the supporting means forming a connectionibetween the respective strands and the respectiveV end of said seriesof shafts,- said. connecting means including a double pivotal link` pivotable about spaced parallel axes normal to. a plane i'ncluding'the adjacent respective strand thereby enabling the ends of said roller assembly to shift forwardA and' backward.

19. A loader assembly comprisingla rigidi' main frame structure, a'- rigid lextensible frame' structure 'telescopieall'ymounted onsaid main framey structure. for movement thereon between'- ani extended andi a retraeted'position', an endless-belt?trainedaround botli'offtheframe struc-- tures, alpairl ofi` laterally spaced flexible' strands trained over; generally parallel courses on each", ofsaid frame structures, each' of: said strandsV being' secured; adjacentthe end portions thereof to-the respective frame struc-fture, supporting means on each of said frame structures' for supporting the respective strands thereon at spaceds locations, said strands being longitudinally shiftable relative to said locations while being so supported, a flexible troughing roller assembly suspended across each respective pair of strands intermediate the supporting means and effective topull said strands downward and-inwardI when loaded, said troughing roller assemblies carrying the conveyingreach of said belt with a loaded portion' of* the conveying reach requiring greater lengths of the respective'flexible strands than an unloaded portion thereof, whereby said strands are longitudinally' shiftable towardl a'loaded portion of said belt in response tofdownwardl movement' of the troughing roller assembliesaccompanied by increased downward and inward deflections of? said strands when loaded.

20.y A loader assembly comprising a rigid main frame` structure, a rigid extensible frame structure teleseopicallyI mounted on said main frame structure for movementthereon between an extended and a retracted position, an endless belt trained around both of the frame structures, a-pair of laterally spaced exible strands for each frame" structure, said strands each being secured adjacent the' end portions thereof tovthe respective frame structure; supports on the frame structure for supporting the respective flexible strands thereon with the supports being spaced along the lengths of saidy respective flexible strands, troughing assemblies spaced-along the lengths of each pairv of said exible strands at locations remote from said supports for guiding the conveying reach of the belt, each troughing assembly comprising a plurality of 'flexible interconnected rollers and means for connecting` the end rollers of each troughing assembly to the respective adjacent flexible strand, said means comprising a hanger supported on the respective exible strand and a doublev articulated connection between the hanger and theresp'ective end roller, whereby upon movement of an off-- center conveying reach thereacross said troughing assemblies are automatically shiftable to a position to'retain such reach toward the center of said strands.

2l. A` loader assembly comprising a wheel mounted chassis, a rigid main frame structure pivotally mounted at one end thereof adjacent the forward end of the chassis and extending rearwardly therefrom with the other' end of the rigid main frame being free and movable ine a substantially-vertical plane relative to the chassis, meansfor moving the free end in the vertical plane including a pair ofspaced apart arms each having'one end pivotall to'th'e rnain frame adjacent the free end thereof with the other free end of each arm engaging the chassis, arigid extensible frame structure telescopically mounted to thev free end of said main frame structure for sliding movement thereon between an extended and retracted position, means for moving said extensible frame structure between-saidpositions, a single endless belt trainedaround both of the frame structures, a pair of laterally spaced'l flexible strands for each frame structure, each of said strands having the end portions thereof secured. tothe respective frame structure, support means on-each-frame' structure for supporting the respective strandsV thereon, said support means including means clamping the respective' strands against relative rotation, a pluralityv ofI elongated troughing roller assemblies are transversely exible along the length thereof and extending transverselyl between and attached to the respective pair of strands for supporting the conveying reach of the belt,

said troughing roller assemblies being spaced along the respective strands from the support means to provide twistable length of the strands between the support means and the troughing roller assemblies, each of said troughing roller assemblies including a pair of end lever members each having a portion clamped to respective ones 0f the strands against rotation relative thereto and having means interconnecting opposite portions of said lever members, whereby flexing of the troughing roller assemblies under transversely applied load is resisted by twisting of the twistable lengths of the strands by said lever members so said load is supported at least in part by the torsional resistance of the exible strands.

22. A loader assembly comprising a rigid main frame structure, a rigid extensible frame structure telescopically mounted on said main frame structure for movement thereon between an extended and a retracted position, each of said frame structures having flexible strand means trained therealong, each of said strand means being secured adjacent the end portions thereof to the respective frame structure, supporting means on each of the frame structures for supporting the respective strand means, an elongated belt carrying anti-friction means adapted to support a conveying reach of a conveyor belt for movement thereacross, said anti-friction means being ilexible in a direction generally transverse to the length thereof and connecting means connecting said anti-fric tion means to said strand means remote from said supporting means for exing movements of the strand means and anti-friction means under loads applied to the anti-friction means.

References Cited in the tile of this patent UNITED STATES PATENTS 1,748,301 McKinlay Feb. 25, 1930 2,773,257 Craggs et al. Dec. 4, 1956 FOREIGN PATENTS 570,034 Great Britain June 19, 1945 932,117 Germany Aug. 25, 1955

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