2. FOR USE IN A BELT CONVEYOR, A BELT TRAINING TROUGHING IDLER ASSEMBLY IN WHICH TRAINING ROLLERS IN THE ASSEMBLY ARE AUTOMATICALLY MOVABLE TO A NEW TRAINING POSTIION UPON REVERSAL OF THE DIRECTION OF BELT TRAVEL SOLEY IN RESPONSE TO PASSAGE OF THE BELT THEREOVER, SAID IDLER ASSEMBLY INCLUDING, IN COMBINATION, A ROLLER ASSEMBLY, SAID ROLLER ASSEMBLY HAVING AT LEAST ONE INTERMDEIATE ROLLER FLANKED BY A PAIR OF WING ROLLERS, THE OUTERMOST END PORTION OF EACH WING ROLLER BEING SWINGABLE IN A PLANE GENERALLY PARALLEL TO THE PLANE OF THE BELT PASSING THEREOVER INTO A NEW TRAINING POSITION CONSISTENT WITH THE DIRECTION OF BELT TRAVEL, A SUPPORTING AND REPOSITIONING ARM FOR EACH WING ROLLER, EACH ARM BEING CONNECTED, AT ITS UPPER END PORTION TO THE OUTERMOST END PORTION OF AN ASSOCIATED WING ROLLER,
July 23, 1963 R. F. LO PRESTI AUTOMATICALLY REVERSABLE TROUGHING IDLER ASSEMBLY Filed D60. 29, 1959 3 Sheets-Sheet 1 INVENTOR.
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AUTOMATICALLY REVERSABLE TROUGHING IDLER ASSEMBLY Filed Dec. 29, 1959 3 Sheets-Sheet 5 INV ENT OR.
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United States Patent 3,098,558 AUTGMATIQALLY REVERQABLE TROUGG HDLER ASSEMBLY Roy F. Lo Presti, Chicago, lllL, assignor to Goodman Manufacturing Company, Chicago, ill, a corporation of Illinois Filed Dec. 29, 1959, Ser- No. 862,561 5 Claims. (Cl. 198-202) This invention relates generally to flexible belt conveyors and particularly to means for automatically repositioning the training rollers of a troughing idler assembly used in such conveyors into a belt training position automatically upon reversal of direction of belt travel.
Flexible belt conveyors of the type illustrated in the Craggs et al. Patent No. 2,773,257 have come into increasingly widespread use in recent years due to their many inherent desirable features such as high carrying capacity, low cost, and ease of installation and maintenance. These conveyors consist essentially of a pair of flexible rope side frames such :as wire ropes or cables which are supported a fixed distance apart by suitable support structure, such as ground engaging support stands or an overhead framework. A plurality of tnoughing idler assemblies :are spaced along the strands to form a bed for the conveying reach of a flexible conveyor belt. These troughing idler assemblies generally comprise a plurality of rollers which may be aligned or slightly offset with respect to one another along the longitudinal axis of the conveyor. Suitable return roller assemblies are spaced along the conveyor to form a bed for the return reach of the belt. Since the return roller assemblies support no load other than the weight of the belt itself, they are generally spaced at substantially greater intervals than the conveying assemblies. The troughing idler assemblies may either be fully flexible, such as illustrated in the Craggs et al. patent, or fully or partially cradled. In the fully flexible assembly, the rollers are free to flex with respect to one another in a generally vertical plane, whereas in the partially or fully cradled assembly, the rollers are fixed or only partially flexible in a generally vertical plane with respect to one another.
One problem common to all flexible belt conveyors, both of the flexible strand and rigid side frame type, is that of belt training. It is well known that the passage of a flexible conveyor belt over a roller generates a frictional training force which tends to cause the belt to either run true over the roller, or to veer to one side or the other. It is generally considered that this force or training effect is exerted in a direction substantially perpendicular to the longitudinal axis of the roller. If the training effect parallels the direction of belt travel, the belt will run true or centered over the roller. If the training effect diverges from the direction of belt travel, the belt will tend to veer off in the direction of the training effect.
In a three roller assembly, as illustrated in the Craggs et al; patent, it is highly desirable that the outer ends of the flanking or wing rollers be canted forwardly (or inwardly) in the direction of belt travel with respect to the When the rollers assume this position, the training effect of each wing roller is directed inwardly toward the center of the conveyor. If equal transverse widths of the belt pass over each wing roller, and each roller is canted the same amount, the inwardly directed training effects will cancel one another out and the belt will run true over the assembly. Should the belt veer to one side, the training effect exerted by the roller up which the belt climbs urging it back to centered position will overbalance the training effect of the opposite roller, since the magnitude of the training effect is roughly proportional to the amount of belt in contact with the 33%,558 Patented July 23, 1963 "ice roller. When the outer ends of the wing rollers are therefore canted in the direction of belt travel, the assembly is automatically self-training or centering because any displacement of the belt to one side or the other will induce an unbalanced training effect or force which automatically urges the belt back to a centered position.
When the outer ends of the wing rollers are canted upstream with respect to the direction of belt travel, the opposite effect occurs. An increase of belt roller contact to one side will cause a progressively increasing training effect to occur which urges the belt even further outwardly. It is, therefore, always highly desirable to position the outer ends of the wing rol'lers in a downstream direction with respect to their inner ends.
Various schemes have been proposed for automatically insuring that the wing rollers will assume a downstream orientation upon reversal of belt travel. In one arrangement, the outer end of the wing roller shafts are freed up and rest upon a slideway which is parallel to the direction of belt travel. The roller is free to flex about its inner end as a pivot and the slideway permits the roller shaft to be oriented in opposing directions, depending upon the direction of belt travel. This embodiment may not be practical in every environment, particularly uphill conveying, because the sliding friction between the roller shaft and the race on which it slides may be greater than the rolling friction between the belt and the roller, particularly when the belt runs empty. As a result, the roller may not move to its new training position immediately upon reversal of the direction of belt travel.
In another arrangement, the outer ends of the wing roller shafts are connected to a rocker arm which is pivoted at its lower end about a relatively fixed base or supporting structure. The principle of operation is substantially the same as in the first described variation. That is, the rolling friction between the belt and roller is intended to be sufiicient to swing the roller about its inner I end, and consequently the upper end of the rocker arm into a new training position, upon the reversal of direction of belt travel. This scheme, however, is also not always practical, particularly when the length of the rocker arm is short because, since the center of rotation of the arm is in effect fixed, the roller shaft must move slightly vertically as well as horizontally in its travel from one position to another. The rolling friction between the belt and roller is not always suflicient to urge the roller into the new position against the weight of the roller.
Accordingly, va primary object of this invention is to provide a troughing idler assembly for flexible belt conveyors which automatically repo-sitions the training rollers in the roller assembly into a training position automatically in response to reversal of direction of travel of the belt.
Another object is to provide an automatic troughing idler assembly in which the outer ends of the training rollers move along a horizontal path.
A further object is to provide a troughing idler assembly having a pair of belt training rollers swingable about .in its .travel from one training position to another, the
length of the rolling arm being relatively short as contrasted to prior art structures.
Another object is to provide an automatic belt training troughing idler assembly which automatically cants the wing rollers into a downstream training direction in response to reversal of direction of belt travel which is utilizable in fully flexible, semi-cradled or fully-cradled troughing idler assemblies.
Other objects and advantages of the invention will become apparent upon a reading of the following description and claims.
The invention is illustrated more or less diagrammatically in the accompanying drawings, wherein:
FIGURE 1 is a sectional view through the flexible belt conveyor of FIGURE 2 taken substantially along the line 11 of FIGURE 2;
FIGURE 2 is a side elevation of a flexible belt conveyor illustrating the present invention;
FIGURE 3 is a partial end view of the training idler assembly of FIGURE 1 taken substantially along the line 33 of FIGURE '1;
FIGURE 4 is a top plan view with the belt and other parts omitted for clarity taken substantially along the line 4-4 of FIGURE 1 illustrating the direction of the training forces exerted by the individual rollers on the belt;
FIGURE 5 is a schematic view of one form of roll- Zing arm utilized in the training assembly illustrated best in FIGURE 3;
FIGURE 6 is another embodiment of a rolling arm; and
FIGURE 7 is yet another embodiment of a rolling arm.
Like reference numerals will be used to refer to like parts throughout the following description of the drawmgs.
In FIGURE 2, a portion of a flexible belt conveyor of the general type illustrated in the Craggs et al. Patent No. 2,773,257 is illustrated. The conveyor is indicated generally at 10 and consists essentially of a pair of flexible strands 11 and 12 which are maintained a substantially fixed distance apart by a support structure. The support structure, in this instance, is a plurality of ground engaging support stands 13, 13, see also FIGURE 1. The strands are received in the U-shaped saddle members 14 and 15 which are welded or otherwise suitably secured to the upper ends of the stands, and any suitable means may be utilized to adjust the vertical height of the stands to insure that the seats of the U-shaped members lie in a common horizontal plane. Since the details of the stands do not of themselves form an essential part of the invention, they are not further illustrated or described. The conveyor rests on the floor F, in any suitable environment such =as a coal mine.
The stands are maintained a substantially fixed distance apart by a cross brace or strut 16, shown on FIGURE 1, which is welded to the bottom members of the stands. A return roller assembly, indicated generally at 17, includes a return roller 18 rotatable about a dead shaft 19 which in turn is supported in brackets 20 connected to the cross brace 16. The assembly supports the return reach 21 of a flexible conveyor belt.
A plurality of troughing idler assemblies are indicated generally at 25, -25. The troughing idler assemblies consist, in this instance, of a training roller assembly 26 which includes a center, primary load carrying roller 27 flanked by a pair of wing or training rollers 28, 29. The roller assembly 26 is supported in this instance, by suitable supporting structure indicated generally at 24 which in turn is connected to the flexible strands 11 and 12 by connecting means indicated generally at 30, 31. In this instance the connecting means are rope clamps. The troughing idler assembly supports the conveying reach 32 of the flexible conveyor belt.
Each of the rollers consists of a shell which rotates about a dead shaft. The shafts are indicated at 33 (shown best in FIGURES 3 and 4) and 34, 35 for the center and wi s l er e pectively.
The supporting means 24 for the roller assembly 26 consists essentially of three connecting braces 36, 37 and 38 which are pivotally interconnected as indicated generally at 39 and 40 for generally vertical flexing movement with respect to one another. Each of the braces has upwardly projecting arm members which are connected to the dead shafts of the rollers.
Center brace 36 is welded at each end to tubular members 41, 42, and a pair of upwardly projecting arms 43, see FIGURE 3, and 43a, shown best in FIGURE 4, are welded to the tubular members. The arms may be formed in any convenient shape, the truncated trapezoid of FIGURE 3 being only exemplary, and the upper edge i slotted as at 43b to receive center roller shaft 33. To prevent rotation of the shaft in the slots, a pair of flats may be milled on opposite sides of the shaft, the flats fitting into the slot with a slight clearance therebetween.
The supporting structure for each of the wing rollers is substantially the same, and for purposes of illustration, the structure supporting wing roller 28 only will be described.
Connecting brace o-r tension member 37 is welded at its inner end to a tubular member 44 through which a pivot pin 45 passes. The bore of tubular member 44 is aligned with that of center tubular member 41 and pivot pin 45 passes through each. Suitable cotter pins or other means 46 prevent unintended axial movement of the pivot pins along the bores. An arm member 47 is welded to tubular member 44 at a substantially right angle to tension member 37. A pair of ears 48 receive the inner end of dead shaft 34, and a pivot pin 49 permits rotation of the roller about its inner end in a plane genera-11y parallel to the plane of the belt lying thereon. Arm 47 extends upwardly a distance sufiicient to provide clearance between the roller and tension member 37.
The outer end of wing roller shaft 34 is connected to the upper end of a rolling arm 50. The shaft is loosely received in an aperture in the upper end of the arm so that the shaft and arm may rotate relative to one another. A fixed washer 51 and cotter pin 52 prevent unintended axial movement of the rolling arm along the shaft.
The lower end of rolling arm is slotted as at 53 and lies flush against a supporting plate 54 which in turn is welded or othenwise suitably secured to the roller assembly connecting means 30. In this instance, the back of the supporting plate 54 has been welded to the outside sur-face of connecting clamp 30, and the upper surface of the clamp abuts the lower side of brace 37. The bottom edge of rolling arm 50 is arcuately contoured as at 56 whereby it may roll along the upper surface 57 of a ledge 57a formed at the bottom of plate 54. In this instance, the bottom of the plate has merely been bent outwardly to form the rolling surface.
Rolling arm 50 is secured to the plate 54 by a pivot pin 58 passing through aperture 53 in the rolling arm. The amount of swing of the arm is limited by a pair of opposed upstanding flanges 59 and 60 which engage the edges of the armto thereby limit its traverse.
In FIGURES 3 and 5, the rolling arm engaging surface 57 of ledge 57a is flat or planar and the ledge engaging surface 56 of the rolling arm is contoured. As can best be seen in FIGURE 5, the point at which roller shaft 34 is connected to rolling arm 50 lies on the center about which the are 56 is struck. The rolling surfaces 56 and 57 are so contoured that the point of connection of shaft 34 to arm 50 will traverse a horizontal path as the arm moves the roller from one training position to another.
In FIGURE 6, rolling arm supporting plate 62 is formed with an arcuately shaped ledge 63a. The edge engaging surface 64 of rolling arm 65 is substantially flat, and the arm engaging surface 63 of the ledge is arcuate.
In FIGURE 7, roller supporting plate 66 includes ledge 67a having arm engaging surface 67 which is formed 1 on a somewhat greater radius than ledge 63a. Ledge engaging surface 68 of rolling arm 69 is likewise formed on a somewhat larger radius than are '56.
Although a roller assembly having rollers axially offset from one another, individual supporting frames, and vertical pin connections between the inner ends of the wing rollers to their supporting members has been illustrated and described, it will at once be apparent to those skilled in the art that the invention is not limited to this specific arrangement, the above construction merely being one of many which could be chosen for purposes of illustration.
The use and operation of the invention is as follows:
In order to insure that the training rollers 28, 29 quickly and easily move to a new training position upon reversal of the direction of belt travel, it is desirable to insure that the outer end portions of the rollers move along a straight path so that movement of the roller includes no vertical lift component. This movement is accomplished in the present structure by connecting the outer ends of the wing roller shafts to a rolling arm 50, 65, or "69 which makes rolling contact at its lower edge with suitable supporting structure 57a, 63a, or 67a, respectively.
In FIGURES 3 and 5, for example, the curve or are 56 is struck around a center 70 which is, in effect, the exact point of connection of the wing roller shaft to the rolling arm. The rolling arm engaging ledge 57 will, therefore, always be tangent to the radius of circular are 56 at the point of contact between the rolling arm and the ledge. As a result, when the roller 28 moves from the solid to the dotted line position of FIGURE 5, the path of travel 71 will be a straight line, Stops 5 9, (it) limit the traverse of rolling arm 50 to thereby define the extreme training angle of the wing roller.
In FIGURE 6, the relationship of the edge engaging surface 64 of rolling arm 65 and the rolling arm engaging surface 63 of ledge 63a have been reversed from the form shown in FIGURE 5. Although the relationship of the rolling surfaces has been reversed, they are so contoured that the point of connection 70 of the training roller to the arm traverses a horizontal path through all relative positions of the arm and ledge 63a.
In FIGURE 7, the contour of both the ledge engaging surface 68 of rolling arm 69 and the roller arm engaging surface 67 of ledge 67a have been curved, but they are so related that as the roller moves from its solid line position to a dotted line position, its point of connection 70 to rolling arm 69 again moves along a horizontal path. In other words, in this embodiment, as in the other embodiments, the bearing surfaces of the rolling arm and ledge are so contoured that the points of connection of the training roller to the arms traverse a horizontal path through all relative positions of the arms and ledges.
One of the great advantages of the invention is the fact that an extremely short rolling arm may be utilized because it is the contour of the lower edge of the rolling arm in relation to the ledge which determines the vertical displacement of the connecting point 70, and not the length of the rolling armitself.
It should also be understood that the rolling arms 50, 65, and 6 9 have been shown as though lying in a vertical plane, whereas actually they are slightly inwardly tilted as seen in FIGURE 1. Ibis slight tilt may cause an extremely small vertical rise of point 70 as it moves along path 71, but this rise can be easily compensated for by appropriate design of the rolling surfaces.
Although three embodiments have been illustrated and described, it will be understood that the foregoing description is illustrative only and not definitive. Accordingly, the scope of the invention should not be limited except by the scope of the following appended claims.
1. A belt training troughi-ng idler assembly in which at least a selected roller is automatically moved to a new training position upon the reversal of belt travel solely in response to passage of the belt thereover, said troughing idler assembly including, in combination,
a roller assembly having at least one training roller,
means for supporting the training roller which enables it to move to a new training position upon reversal of the direction of belt travel,
said supporting means including a rolling arm connected at its upper end portion to the outermost end portion of the training roller and a stationary base,
said stationary base having a surface upon which the lower end portion of the rolling arm rests in rolling engagement,
the engaging surfaces of the rolling arm and the stationary base being so contoured that the point of connection of the training roller to the rolling arm traverses a horizontal path thru all relative positions of the rolling arm and the supporting means, and,
stop means for limiting the movement of the outermost end portion of each wing roller.
2. For use in a belt conveyor,
a belt training troughing idler assembly in which training rollers in the assembly are automatically movable to a new training position upon reversal of the direction of belt travel solely in response to passage of the belt thereover,
said idler assembly including, in combination,
a roller assembly,
said roller assembly having at least one intermediate roller flanked by a pair of wing rollers,
the outermost end portion of each wing roller being swingable in a plane generally parallel to the plane of the belt passing thereover into a new training position consistent with the direction of belt travel,
a supporting and repositioning arm for each wing roller,
each arm being connected, at its upper end portion to the outermost end portion of an associated wing roller,
a surface of the lower end portion of each arm resting in rolling engagement on an associated stationary base,
the engaging surfaces of each repositioning arm and its associated stationary base being so contoured that the outermost end portion of each wing roller traverses a horizontal path as each arm rolls along its supporting surface, and
stop means for limiting the movement of the outermost end portion of each wing roller.
3. The idler assembly of claim 2 further characterized in that the rolling surface on the lower end portion of each rolling arm is arcuately con-toured, and
the associated supporting surface is substantially planar.
4. The idler assembly of claim 2 further characterized in that the rolling surface on the lower end portion of each rolling arm is substantially planar, and
the associated supporting surface is arcuately contoured.
5. The idler assembly of claim 2 further characterized in that the rolling surfaces on the lower end portion of each rolling and the associated supporting surfaces are each arcuately contoured.
References Cited in the file of this patent UNITED STATES PATENTS 897,092 Gregory Aug. 25, 1908 2,179,186 Kendall Nov. 7, 1939 2,261,088 Kendall Oct. 28, 1941 2,880,851 Salmons Apr. 7, 1959 2,896,774 Long et a1. July 28, 1959