US3070220A - Automatic two directional belt training troughing idler assembly for low clearance operations - Google Patents

Description

Dec. 25, 1962 55 3,070,220

R. F. RIS AUTOMATIC TWO DIRECTIONAL BELT TRAINING TROUGHING IDLER ASSEMBLY FOR LOW CLEARANCE OPERATIONS Filed Dec. 16, 1959 2 Sheets-Sheet 1 INVENT OR.

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' completely adequate.

- that is, in installations in which the clearance is 4 feet or less, it is often desirable to either use cradled assemblies UllilICCi t 3,070,220 AUTOMATIC TWO DIRECTIONAL BELT TRAIN- ING TROUGHING IDLER ASSEMBLY FOR LOW CLEARANCE OPERATIONS Ralph F. Risse, Chicago, Ill., assignor to Goodman Manufacturing Company, Chicago, 111., a corporation of Illinois Filed Dec. 16, 1959, Ser. No. 859,989 6 Claims. (Cl. 198-192) This invention relates generally to flexible strand conint veyors and particularly to a troughing idler assembly for such a conveyor designed for use in low clearance operations.

Flexible strand conveyors of the type lllustrated 1n the Craggs et al. Patent No. 2,773,257 have come into increas-' ingly widespread use due to their many inherent desirable belt. A plurality of return roller assemblies are usually supported by the support structures or, alternately, they may besuspended from the flexible strands or the roof to form a bedfor the return reach of the conveyor belt. Since the return roller assemblies support no load other than the weight of the belt, they are generally spaced. at

' somewhat greater intervals than the troughing idler as- "'semblies. r I

The troughing idler assemblieswhich support the co'nveying reach of the belt may either be fully flexible, as ilustrated in the Craggs et al. patent, or partly or entirely rigid. In a fully flexible assembly, the outer ends of the roller assembly are free to move both inwardly and downwardly in response t'o'i'mposition of a load, whereas in a rigid assembly the rollers are generally carried by a substantially rigid support structure or cradle which prevents inward movement of the ends of the assembly. Various modifications have been proposed from time to time which combine features of both the fully flexible and completely rigid assemblies, but for purposes of illustration only these two types will be discussed.

These conveyors are widely employed in the coal mining industry to transfer coal from the face of the seam back to a remote processing station. In installations in which adequate head room is present, which for purposes of illustration will be assumed to be 4 feet or more, the

type of conveyor illustrated in the Craggs et al. patent is In low seam operations, however,

or to modify the troughing action of the fully flexible idler assemblies to prevent interference of the assemblies with i the return reach of the belt. It is not always desirable to use cradled assemblies, since the angle of trough is generally limited to a fixed angle. To prevent undue sag when using a fully flexible assembly, it has become common practice to increase the tension in the flexible rope side frame from a normal value of around 2,000 pounds up to 5,000 pounds.

It is well known in this field that a troughing idler assembly imparts a training effect to a belt as the belt passes over the assembly. Generally, this training effect is directed in a direction substantially perpendicular to the longitudinal axis'of the troughing idler assembly. If the assembly is not positioned perpendicularly to the direction of'belt travel, the belt will be urged to a decentered or detrained position.

It is highly desirable in any conveyor installation to bring the flexible strands in under the edge of the belt. By so doing, lumps of conveyed material, such as coal, near the teetering point at the edge of the belt fall completely off the conveyor and do not lodge in the pocked formed between the edge of the belt and the flexible strand. Should such a pocket exist, the movement of the belt will tumble the lumps of conveyed material along this pocket until it strikes the next downstream conveyor assembly knocking it out of perpendicular alignment with the belt, and into a detraining position, as explained above.

Such an arrangement whereby the strands are located beneath the edge of the belt is also important from a safety standpoint. Miners often ride the belts into and out of the mine, and there is considerable danger to them as they hop onto or off a moving belt. By placing the flexible strands beneath the belt, the danger of catching an arm, leg or loose clothing in the pocket is completely eliminated, and the belts may be run at a relatively high rate of speed.

Increasing the tension in the flexible side frames to reduce sag often raises other problems, particularly the problem of installing the individual assemblies along the rope strands. If, for example, it is desired to place the flexible strands under, or at least in general vertical alignment with, the edge of the conveyor belt for belt-training and safety reasons, jacks or other special equipment may be needed to force the strands close enough together to a point where the troughing idler assemblies can be connected thereto. This is a cumbersome process at best even where adequate head room is available, and in low seam work the difficulties become acute.

Another factor affecting the amount of training effect exerted by the troughing idler assembly on the belt is the amount of contact between the belt and assembly. If there is substantial contact between the center roller in a three-roller troughing idler assembly and the belt, the chances are exce lent that satisfactory belt training characterislics will follow. If the belt makes only intermittent, or in effect, partial contact with the center roller, detraining of the belt may follow. Since many of the belts in use in the coal mining industry today are relatively stiff, they assume a smooth curved contour when passing over a troughing idler assembly and thereby make only point or partial contact with the assembly. This effect, of course, is at a maximum when the hilt is running empy, since there is no load on the belt when forces the belt to lay tight against the assembly to closely conform to its contour. This is another reason why a fairly pronounced troughing contour cannot be tolerated in low seam operations, particularly when the belt runs empty.

Accordingly, the primary object of this invention is to provide a troughing id er assembly for a belt conveyor which has a relatively shallow troughing contour to thereby provide good unoaded belt training charactedstics and which can be installed in a conveyor utilizing normal strand tensions.

Another object is to provide a troughing idler assembly especially adapted for installation in low clearance operations in which the pivot point between fully flexible troughing rollers is located substantially downwardly from the point of overlap of the individual rollers whereby the tension path along which load on the belt is transmitted to the strand lies considerably below the longitudinal axis of the rollers.

Yet a further object is to provide a ful y flexbe troughing idler assembly especially adapted for installation in low clearance rperations which has a relatively shallow unloaded troughing contour and in which the-action of 3 the belt on the rollers automatically orients the rollers into a training position.

Yet a further object is to provide an automatic belt training troughing idler assemly having a relatively shallow unloaded troughing contour in which the degree of fujl flex motement between the wing and center rollers is limited to thereby prevent undue sag of the entire assembly.

Other objects and advantages of the invention will become apparent upon a reading of the following description of the invention.

The invention is illustrated more or less diagrammatically in the accompanying drawings, wherein:

FIGURE 1 is an elevational view of a portion of a fiexib e strand conveyor illustrating the invention;

FIGURE 2 is a sectional view through the conveyor of FIGURE 1 taken substantially along the line 2--2 of FIGURE 1;

FIGURE 3 is a top plan view taken subtantially along the line 3-3 of FIGURE 2;

FIGURE 4 is a detail view illustrating the connection between adjacent roller supporting structures taken substantialiy along the line 44 of FIGURE 2; and

FIGURE 5 is a detail view taken substantially along the line 5--5 of FIGURE 3 il ustrating the extreme de- .gree of flexure between the center and wing rollers permitted by the structure of the present invention.

Like reference numerals will be used to refer to like parts throughout the following description of the drawmgs.

In FIGURE 1, a flexible strand conveyor is indicated generally at resting on the floor 11 which may be the floor of a coal mine, for example. The roof of the mine is indicated generally at 12 and, as is apparent from the draw ngs, the cearance is relatively low. The conveyor consists essentially of a pair of generally parallel flexible strands 13 and 14 which are supported and maintained a subst ntially fixed distance apart by a supporting structure indicated generally at 15. In this instance, the support structures include a pair of vertically adjustable te escoping support stands 16 and 17 which are maintainad a fixed distance ap rt by a cross brace or strut 18. The stands rest on any suitable base 19 and any suitable means for vertically adjusting the height of the stand may be utilized. Since the details of the support stands do not of themselves form a part of the invention, they are not further illustrated.

A pair of tubular members 20 and 21 are welded or otherwise suitably secured to the cross brace 18 and carry suitable clamps 22, 23 or other seating members which receive the flex'ble strands 13 and 14. Eye- bolts 24, 25 force the strand into snug engagement in the seats in clamps 22. 23.

A return roller assembly is indicated generally at 30. The assembly includes, in this instance, a return roller 31 secured to the telescoping support stands 16 and 17 by suitable bracket structures 32, 33 which receive the end portions of roller shaft 34. The return roller 31 supports the reiurn reach 35 of a flexible conveyor belt.

A troughing idler assembly is illustrated generally at 39. The assembly, in this instance, is shown as including a pair of end or wing rollers and 41 which flank an intermediate or center primary load carrying roller 42. The wing rollers are offset with respect to the center roller along the longitudinal axes of the conveyor, as best illustrated in FIGURE 3, and form a support for the conveying reach 43 of the flexible conveyor belt. Al though only three rollers have been shown, it should be understood that one or more intermediate rollers may be empoyed as well as one or wore wing rollers flanking the intermediate roller or rollers.

The rollers are secured to the flexible strands 13 and 14 by a roller supporting structure indicated generally at and connecting structure illustrated generally at 51. The roller supporting structure 50 consists essentially of a plurality of elongated frame members 52, 53, 54 which support rollers 41, 42, and 40, respectively. Elongated frame member 54, for example, includes a pair of upstanding roller shaft supporting members or arms 55 and 56 adjacent its outer and inner end, respectively. A pair of milled flats on opposite sides of right wing roller dead shaft 40a are received in a vertical slot in arm 56 and a horizontal slot in arm 55. Arm 56 is considerably longer than arm 55 to thereby elevate the inner end of wing roller 40 a substantially greater distance above frame member 54 than the outer end. In this instance, the outer end of frame member 54 has been turned up to provide support member 55, but a separate member could be utilized. Left frame member 52 likewise carries outer and inner upwardly projecting end members or arms 57 and-58 which receive the dead shaft 41a of roller 41.

Center, or intermediate, frame portion 53 likewise has a pair of upstanding brackets or arms 59, 60 adjacent its ends. Arms 59, 60 receive center roller dead shaft 42:: and maintain the center roller at an elevation substantially equal to the elevation of the inner ends of the wing rollers.

The intermediate frame portion 53 is flexibly connected to end or outermost frame portions 52, 54 by the structure illustrated best in FIGURE 4. Each of frame portions 52 and 53, which are shown as comprising a relatively flat plate having a width substantially larger than its thickness, are welded to a pair of sleeves 64, 65, and 66, 67, as indicated at 68 and 69. The sleeves are aligned one with another to form a borewhich receives pivot pin 70. The flat plates or frame portions 52, 53 overlap one another a substantial amount to avoid excessively. high bending moments at the joint. This arrangement permits the individual rollers to flex freely with respect to one another to provide much the same action as that illustrated in the Craggs et al. patent but, since the rollers are offset along the longitudinal axis of the conveyor, it is possible for them to overlap during their flexing movement, as illustrated, for example, in FIGURE 5. Because of the overlapping of the rollers, the effective points of flexure of the wing and center rollers with respect to one another is about the pivot points 70.

Limit or stop means are indicated generally at 72, 73. In this instance, the limit means consists merely of a stop block whose lower boundary 74 is welded to center frame portion 53 to present an abutment surface 75 directly in line with and engageable by upwardly projecting arm 58 of left frame portion 52. The limit of flexure between rollers can be regulated by varying the angle of inclination of abutment surface 75.

The strand connecting means 51 are welded as at 76 to the underside of outermost frame portions 52, 54 and are so positioned that they are in a general vertical alignment with the edge of the conveying reach 40 of the belt when the belt runs centered over the assembly.

Means for canting or orienting the wing rollers in a training direction are illustrated in FIGURES 1 and 3. In FIGURE 3, slots or races 78 and 79 are formed in the upstanding members 55, 57 of the outermost frame portions. Shafts 4%, 41a of Wing rollers 40, 41, respectively, extend through these slots and slide therealong. Swing 1g movement of the Wing rollers about the connection between their shafts and the inner arms 56, 58 is possible because of a slight looseness or play in the connections between the rollers and the frame arms. Special connections at the inner ends of the shafts could, of course, be utilized to permit a wider arcuate sweep of the wing rollers about the pivot points, but for all practical purposes a reorientation of the roller of two or three degrees one way or the other from a position perpendicular to the direction of belt travel will be sufiicient. To aid in the repositioning of the wing rollers when the direction of travel of the belt is reversed, a series of bumps or projections 80 have been welded to the outer ends of the rollers.

Although only a single troughing idler assembly has been illustrated and described, it should be understood that each of the assemblies in FIGURE 1 can be substantially identical, or, in any given conveyor installation, this particular troughing idler assembly can be located at selected intervals along the strands.

The use and operation of the invention is as follows:

In order to obtain a relatively shallow troughing contour when a belt runs unloaded without increasing the tension in the flexible strands of the conveyor, the roller supporting structure illustrated best in FIGURE 2 in effect pulls the strands inwardly under the belt to thereby separate the tension path from the longitudinal axes of the rollers of the assemblies. Thus, in FIGURE 2, a load imposed on the belt will be transmitted through the upwardly projecting roller supporting arms 55, 56, 57, 58, 59, 60'tooutermost frame members 52, 54 and thence to fiexible'strands 13 and 14. Since roller supporting arms 56 and 58 are substantially longer than the outermost arms 55, 57, the longitudinal axes of the wing rollers at their inner-ends will lie a substantially greater distance above the flexure point 70 than will the longi.-. tudinal axes of the rollers at their outer ends above the points of connection of the assembly to the strands. For convenience of illustration, the angle formed between the outermost frame portions 52, S4 and the horizontal has been indicated at X and represents in effect the tension angle. Similarly, the angle formed at the intersection of the extension of the longitudinal axes of the wing rollers and a line passing through the flexure points 70 and the points of connection of the assembly to the strands has been indicated at Y. This angle represents, in elfect, the amount the roller is olfset from the tension path. The illustrated structure permits increases in the tension angle up to a relatively high amount, on the order of 25 degrees or more, which thereby provides a relatively shallow troughing contour. As a consequence, the assembly can be connected to the flexible strand rather easily because the normal strand tensions may be utilized but, at the same time, because of the olfsetting of the roller axis from the tension path as represented by the roller offset angle Y, the troughing contour is maintained relatively shallow. In essence, for any given tension path angle, the greater the roller offset angle, the more perfect the troughing contour becomes in the sense that a relatively flat unloaded troughing contour is maintained, thus promoting good belt contact even with stiff belts. In other words, the greater the tension angle X, FIGURE 3, the lower the rope tension needed to provide good troughing characteristics and good belt-roller contact. This construction is the first in which the tension path and longitudinal axis of the rollers have been separated and eventually converge at the point beyond the boundaries of the conveyor system.

This construction also permits the wing rollers to overlap the center roller when the rollers flex, as best illustrated in FIGURE 5, which promotes good belt contact, particularly when the belt is unloaded and reduces bridging of the belt between adjacent ends of the rollers. Experience has shown that unsupported spans of the belt tend to fail faster than supported spans when subjected to loads.

Otfsetting also exposes the shaft ends and bearings so that they are easily accessible for maintenance and replacement. In fact, by offsetting the rollers, an individual roller may be removed without removing the troughing idler assembly from the strands, and this advantage is achieved while retaining the highly desirable full flexing features of the sausage roller assemblies illustrated in the Craggs et al. patent.

This construction also enables the ropes to be pulled under the belt thus making it safer for workmen riding the belt to get on and off. The chances of knocking the idler assembly out of line due to a detrained belt or by lumps of coal which have caught in the pocket between the belt and adjacent strand are reduced.

The combination of the bumps or projections 80 and the slots 78, 79 formed in upstanding end portions 55, 57 provide quick realignment of the wing rollers should the belt become detrained. Thus, when the belt detrains to the right, for example, the right edge rides up and over the projections 80. Each projection alternately rises and drops the belt onto the roller which imparts a jarring motion to the roller sufiicient to overcome the sliding friction between the end of rollershaft a and the bearing surface 78. The roller will slide into the position of FIGURE 3 and the belt will gradually move back to a center position since the training effect indicated generally at F is exerted in a training direction. The bumps or projections 80 are not training means in themselves. They only serve to cause sliding of the outer ends of the wing rollers into training positions whereby automatic two directional training is achieved.

Although the invention has been shown and described in a low clearance environment, it is not so limited in application. It may, for example, be used in high clearance underground or above ground operations.

The foregoing description is illustrative only, and not definitive. Accordingly, the scope of the invention should only be limited by the scope of the following claims.

I claim:

1. A flexible strand conveyor troughing idler assembly especially adapted for installation in low clearance operations with normal strand tensions, said troughing idler assembly including, in combination, a center roller flanked by a pair of wing rollers, said rollers being shaftmounted, means for supporting said rollers, said supporting means enabling the rollers to flex with respect to one another in a generally vertical plane throughout a limited range of flexure whereby the outermost ends of the wing rollers may move toward and away from one another, said supporting means maintaining the effective points of flexure between the center roller and each wing roller a greater distance below the wing roller shafts thereabove than the distance between the flexible strands and the wing roller shafts thereabove to thereby angularly offset the effective tension path from the axes of the wing rollers, and means for connecting the rollers and the roller supporting means to the flexible strands of a flexible strand conveyor.

2. The troughing idler assembly of claim 1 wherein the roller supporting means includes outer frame members supporting the wing rollers by their end portions, the connecting means being carried by the frame members, and an intermediate frame member flexibly connected to the outermost frame members and supporting the center roller, each of said outer frame members including an inner and an outer upwardly extending arm, said arms carrying a wing roller at their upper ends, the inner arm being longer than the outer arm so as to elevate the inner ends of the wind rollers a greater distance above the eflective points of flexure between the wing and center rollers than the outer ends of the wing rollers above the connecting means, said intermediate frame member maintaining the center roller at approximately the same level as the inner ends of the wing rollers.

3. The troughing idler assembly of claim 2 further characterized in that the center roller is offset in a direction generally perpendicular to the longitudinal axis of the assembly to thereby enable the inner ends of the wing rollers to overlap the outer ends of the intermediate rollers throughout at least a portion of the range of flexure of the rollers with respect to one another.

4. The troughing idler assembly of claim 2 further characterized by and including limit means for limiting 6' the amount of flexure of the wing rollers with respect to the intermediate rollers.

5. The troughing idler assembly of claim 2 further characterized by and including means for canting the wing rollers in the direction of belt travel automatically in response to passage of the belt over the assembly.

6. A flexible strand conveyor troughing idler assembly especially adapted for installation in low clearance operations using normal strand tensions, said troughing idler assembly including, in combination, a center primary load carrying roller flanked by a pair of wing rollers, flexible frame means for connecting the rollers for flexing movement with respect to one another in a generally vertical plane, said flexible frame means including elongated substantially rigid frame members extending substantially the entire length of the rollers, each member having upwardly extending roller supporting arms adapted to support the ends of its associated roller, said elongated flexible frame members being disposed beneath the'rollers, the roller supporting arms adjacent the inner ends of the wing roller frame members projecting upwardly a substantially greater distance than the roller supporting arms at the outer ends of said frame members to thereby enable the troughing idler assembly to assume a shallow troughing contour in unloaded conditions, the frame members supporting the wing rollers being pivotally connected to the frame member supporting the center-roller to thereby provide etfective points of flexure between the center and wing rollers, and means for connecting the wing roller frame members, and consequently the troughing idler assembly, to the flexible strands of a flexible :strand conveyor, whereby the tension path between the flexure points and the strands lies below and is disposed angularly to the longitudinal axis of the wing rollers, the center roller supporting arms extending upwardly a disstance suflicient to maintain the center roller at substantially the same elevation as the inner ends of the wing rollers.

References Citedin the file of this patent UNITED STATES PATENTS acr

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