Abstract:
A method and apparatus is disclosed for providing an indication of the perpendicularity of a conveyor belt idler with respect to a reference line known to be parallel to a direction of movement of a conveyor belt when the conveyor belt is disposed on the conveyor belt idler. An idler roller attachment structure is provided to be temporarily attached to a first idler roller having a first rotational axis. An elongated member is rotatably and axially moveably operatively attached to the idler roller attachment structure along a reference axis of rotation which is parallel to the first rotational axis. A laser, having a laser beam, is operatively attached to the elongated member, the laser beam being perpendicular to the reference axis of rotation.

Description:
RELATED APPLICATION 
       [0001]    Priority is hereby claimed to U.S. Provisional Patent No. 62/301,114 to Reicks, filed Feb. 29, 2016 to a Conveyor Idler Angular Alignment Measurement Device, which describes the construction and use of the present invention and is hereby incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    This invention relates generally to conveyors and a method and apparatus for single handedly giving a visual and quantitative indication of the perpendicularity of each belt conveyor idler to the belt of a conveyor. 
       BACKGROUND 
       [0003]    Testing has shown imprecise idler angular alignment is often a significant source of power loss on a conveyor as well as contributing to the wear and tracking instability of belt conveyors. When an idler roll is not perpendicular to the belt direction of travel, the belt/idler roll condition commonly referred to as “sliding parallel to the roll axis” develops. This continual sliding is resisted by an axial force. This force has lateral and longitudinal components. The longitudinal component resists belt movement, which condition requires additional power. The lateral force component causes roll and belt wear due to the belt undesirably wandering along its designated path. Alignment is focused on the center roll of a three roll idler set since the center roll has the most load and therefore exerts the greatest axial friction force. Minimizing this force is the purpose of the present invention. 
         [0004]    The most common current measurement methods to prevent the aforementioned problem is to use a tape measure in various imprecise ways or, even worse, rely on visual references to support stringers. Positioning a tape measure is usually a two person job and requires two cross measurements for angular deviation measurements. Measuring to adjacent idlers is not the most relevant point of reference since both idlers can be misaligned without verifying alignment to the belt. The outer, or wing, idler roll is the most available but does not offer an easy or accurate location on its exposed circumference for measurement. Alternatively, points on the idler frame can be used but access to the same point on adjacent or near idlers is often obstructed. None of these points are as beneficial as a direct measurement to the center roll since alignment of all of the idler rolls to each other and to the frame may not be tightly controlled by manufacturers. The center roll carries the most load and therefore is most resistance to belt movement if not well aligned. 
         [0005]    WO1995008094 A1 (incorporated herein by reference in its entirety) by inventor Geoff Edwards is dated 1995 and shows a device apparently used in a product produced by Applied Resolution Technologies (ART), an Australian company, that is used for idler alignment. The ART method uses a laser in a manner to be perpendicular to an idler roll so a common datum is created to allow measurement to common features, such as the roll ends, of nearby idlers. The mounting method and principle of operation of the Edwards/ART measurement device/system is difficult to use and is problematical in accomplishing its desired result. 
         [0006]    U.S. Pat. No. 3,664,489 A (also incorporated herein by reference in its entirety) shows an apparatus and method for aligning belt conveyor components such as idler frames and pulleys but is difficult to use. 
         [0007]    Accordingly, there is a need for a method and apparatus to overcome the aforementioned problems and disadvantages of the prior art. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention relates to an apparatus for providing a visual and quantitative indication of the perpendicularity of a conveyor belt idler with respect to a reference line known to be parallel to a direction of movement of a conveyor belt. An idler roller attachment structure is provided to be temporarily attached to a first idler roller having a first rotational axis. An elongated member is rotatably and axially moveably operatively attached to the idler roller attachment structure along a reference axis of rotation which is parallel to the first rotational axis. An indicating component, such as a laser having a laser beam, is operatively attached to the elongated member, the laser beam being perpendicular to the reference axis of rotation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view showing a preferred embodiment of the present invention positioned on an empty belt conveyor, showing also a laser beam emanating from a laser; 
           [0010]      FIG. 1 a    is an enlarged perspective view of an idler mounting arrangement on a conveyor; 
           [0011]      FIG. 1 b    is a perspective view like  FIG. 1  but showing the laser in an alternate position on the conveyor; 
           [0012]      FIG. 1 c    is a perspective view like  FIG. 1 b    but showing two alternate rotary positions and reference line locations; 
           [0013]      FIG. 2  is a perspective view of the preferred embodiment mounted on a conveyor; 
           [0014]      FIG. 2 a    is a perspective view of the preferred embodiment separated from the conveyor and showing its parts and construction; 
           [0015]      FIG. 2 b    is an end view of the preferred device of  FIG. 2 , showing the shape of plates used in mounting the preferred embodiment to idler roll; 
           [0016]      FIG. 2 c    shows invisible roller and invention centerlines 
           [0017]      FIG. 3  is a bottom view of the laser beam initially set to intercept an edge of the conveyor belt, the solid lines showing the visual part of the laser beam and the dashed lines showing an invisible part of the laser beam; 
           [0018]      FIG. 4  is a perspective view similar to  FIG. 1 , but showing the laser beam of the preferred embodiment positioned to detect a target hanging from the belt edge that is at a further distance than the position detected in  FIG. 1 ; 
           [0019]      FIG. 4 a    is an enlarged perspective view of the laser target and beam aligned with belt edge shown in  FIG. 4 ; 
           [0020]      FIG. 4 b    is an enlarged perspective view showing the beam misaligned with the target; 
           [0021]      FIG. 5  is a perspective view of the device installed on return side belt under the conveyor; 
           [0022]      FIG. 5 a    is an enlarged perspective view of a return idler hangar bracket and slot, showing a placement of the preferred embodiment on the underside of the return idler; 
           [0023]      FIG. 5 b    is a perspective view of the preferred embodiment installed on a return idler; 
           [0024]      FIG. 5 c    is an enlarged perspective view of the laser beam intersecting the belt edge; 
           [0025]      FIG. 5 d    is an enlarged perspective view of the laser beam intersecting a belt edge on the other side of an idler; 
           [0026]      FIG. 6  is a perspective view of the laser oriented to use the conveyor structure itself for the reference line; 
           [0027]      FIG. 7  is a perspective view of the laser with a temporary reference line installed such as a taut wire or secondary laser beam; and 
           [0028]      FIG. 8  is a view like  FIG. 1 c    but showing an alternate embodiment with a rigid linear member shown in two alternate rotary positions and reference line locations. 
       
    
    
       [0029]    Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. Certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. The terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein. 
       DETAILED DESCRIPTION 
       [0030]    Referring now to the drawing  FIGS. 1-8 , wherein like reference numerals indicate identical or similar parts throughout the several views, the general location of the preferred embodiment shown in  FIG. 1  is shown installed on a belt conveyor. The relevant conveyor construction comprises a continuously long wide and thin belt formed in a generally symmetrically trapezoidal shape including a center portion  1  and two wing portions  2 . The belt has two edges  4 . When operating, the belt moves in the direction indicated by arrow  5 , which is parallel to the belt edges  4 . The belt is supported by regularly spaced idler sets each comprised of a stationary framework  3  supporting three rollers  12 ,  6 ,  6  which support the belt at the center section  1  and each wing section  2 ,  2  respectively. Each of the roller&#39;s axis is approximately perpendicular to the belt direction  5  though the idler frame construction and its mounting to the supporting structure  9 , typically comprised of structural steel members arranged generally parallel to the conveyor direction.  FIG. 1 a    shows the idler framework mounted to the supporting structure  9  where the idler framework includes a footpad  3   a  as a subcomponent. The footpad  3   a  lays on the support structure and includes slots  10  for passage of bolts  11  which, with associated nuts  11   a , clamp the idler framework  3  to the support structure  9  via holes (not shown) in it. It should be understood that the conveyor is symmetrical about a center vertical plane parallel to the direction of movement  5  so that the same support and clamping construction exists on the idler near the opposite belt edge  4 . When the nut and bolt assembly  11 ,  11   a  is loosened, the slots  10  allow limited independent movement of each end of the idler parallel to direction of motion  5  so that the idler and therefore its rollers  9 , 6  may be adjusted angularly, when only one side of the idler is moved, to be perpendicular to the belt movement  5 . It is the purpose of this invention to indicate when the rotary axis of one of the rolls, typically the center roll  12 , is precisely perpendicular to the belt movement direction  5 . 
         [0031]      FIG. 1  also shows a laser assembly  7  and its approximately vertical beam  8  which passes by and may be partly or wholly intercepted by the belt wing section  2  and its edge  4 .  FIG. 1 b    shows the same laser assembly  7  and beam  8 , no longer vertical, redirected to similarly engage the belt and its edge  4  at a position remote from that in  FIG. 1 .  FIG. 1 c    shows the laser  7  in two (of many possible) rotary positions  28   a  and  28   b  at or near two locations  29   a  and  29   b  along the belt edge  4 . It is to be understood that the laser  8  may be replaced with a straight rod, bar or any form of rigid linear member  8   a  as shown in  FIG. 8  and used the same as the laser beam  8  in the following description. 
         [0032]      FIG. 2  shows the preferred embodiment mounted to the center roller  12  of the idler set. It shows the preferred embodiment in use while  FIG. 2 a    better shows the components and their relationship to one another. In the preferred embodiment shown in  FIG. 2 a    and referring to axes in  FIG. 2 c   , the axis  16   a  of a cylindrically tubular member  13  is established to be parallel to the axis  12   a  of the center roller  12  of the idler through the use of a two pairs of steel plates  14  with V shaped notches  14   a  which are welded to the tube  13  in parallel and accurately shifted position to one another so that each point on all of the V surfaces  14   a  will define a line parallel to the tube centerline for tubes of various diameters. The V surfaces  14   a  are shown in  FIG. 2 b   . Before assembly and welding, thin rectangular magnets  15  are sandwiched between each pair of plates  14  so that their edges are within the periphery of the plates  14  so as that the magnets  15  two larger surfaces make entire contact. 
         [0033]    Still referring to  FIG. 2 a   , a close fitting telescoping and rotating round bar  16  is inserted in the tube  13 . An assembly of laser components including a cylindrical laser  7   a , a laser bracket  7   b  and laser guard  7   c  are mounted to one end of the bar. The bracket  7   b  clamps to the bar  16  and the laser  7   a  so as to position and direct the lasers beam  8  radially from the bar  16  centerline  16   a . Laser guard  7   c  ( FIG. 2 ) is attached to the bracket  7   b  to protect laser  7   a  from damage from incidental contact. The respective components fit and interaction combine to direct the beam  8  within a plane perpendicular to the roller  12  axis of rotation  16   a  where the distance between said plane can be adjustably relocated relative to a parallel plane perpendicular to any point on the roller  16  axis. The laser beam  8  in this embodiment has a cross shaped cross section ( FIG. 3 ) made of two short lineal elements bisecting each other at 90 degrees and laser  7  projecting said beam is assembled so that one lineal element is parallel to the line of rotation  16   a  established by tube  13  and bar  16 . It will be understood that the lineal elements creating the cross shaped beam  8  increase in length with increasing distance from the laser  7   a  creating a divergent beam  8  due to inherent internal working of the laser  7 .  FIG. 2 b    shows the axis  12   a  of the center roll  12  in a parallel orientation to the centerline or axis  16   a  of the bar  16 . 
         [0034]    Additional components, as can best be seen in  FIGS. 2 and 2   a , are an adjustable lock collar  17 , a prop  18  and a balance weight  19 . The collar  17  is initially moved toward the laser end of the shaft as shown in  FIG. 2 a    until the laser is positioned by rotation about and along the tube  13  and bar  16  centerlines  16   a  to point at a desired point such as  29   a  or  29   b  in  FIG. 1 c   . The collar  17  is then moved along the bar  16  to abut against the tube  13  end as shown in  FIG. 2  and then locked to prevent axial movement along the bar  16  by turning the tee handled locking screw  17   a . The prop  18  can be rotated on the tube  13 . As shown in  FIG. 2  it is positioned to prevent the roller  12  from rotating or from the plates  14  from sliding circumferentially on the roller  12  when the preferred embodiment is attached to the roller. 
         [0035]    Since it is convenient that the bar  16  not rotate in the tube  13  due to the offset weight provided by the laser assembly  7 , collar  19  used to prevent the bar  16  from sliding axially out of tube  13  is unbalanced opposite the imbalance provided by the laser assembly. 
         [0036]      FIG. 3  illustrates the portion of the cross shaped laser beam  8  when positioned at a desired location such as  29   a  of  FIG. 1 c    and as seen from below when the beam is near vertical as in  FIG. 1 . It will be understood that the laser beam  8  is light and will be seen only when it intercepts a solid object such as the belt. The invisible portion of the beam is shown in dashed lines in  FIG. 3 . The visible proportion/percentage of the entire beam  8  cross section as projected on the belt  2  may or may not change as the laser  7  and bar  16  assembly is rotated in the tube  13 . If said proportion changes, it is due to a small difference from 90 degrees between the plane swept by rotation of the laser assembly  7  and the vertical plane through the belt edge  4 . Whether said proportion increases or decreases with the rotation depends on whether the angle between said plane and axis  12   a  is greater or less than 90 degrees in the direction of rotation. Such information about perpendicularity of vertical plane containing the belt edge  4  and the center roll  12  axis  12   a  provides information for optimal realignment of the idler assembly by movement at one end of the idler frame  3  along the slots  10  and thereby changing the angle between the said plane and axis. In addition, if the laser  7  is shifted outward by increasing the distance between the stop  17  and tube  13  end while maintaining a rotary position  28   b  relative to an initial angular position  28   a  both creating the beam  8  visibility shown in  FIG. 3 . Said distance may be measured and used with the distance between locations  29   a  and  29   b  along the belt edge  4  during said rotated angle to calculate the existing idler misalignment angle. This misalignment angle is useful to calculate power consumption and for future reference. 
         [0037]      FIG. 4  shows the preferred embodiment with increased accuracy by increasing the distance along the belt edge  4  that the beam  8  is projected. Increasing that distance allows a smaller misalignment angle to be detected.  FIG. 4  shows a target  20  hanging over the belt edge  4  at a distance of two idler spacing intervals. This distance may be more or less but the use of the hanging target  20  prevents the idler wing rollers  6  from intercepting the beam  8  when the laser  7  is rotated to be more horizontal as required to project further distances.  FIG. 4 a    shows the details of construction for the target  20 . The flat hanging plumb bob  20   a  swings on thin flexible straps  20   b  directly below the belt edge  4 . The target assembly  20  is prevented from falling by its weight  20   c  which rests on the belt section  2 .  FIG. 4 a    also shows the cross pattern of the laser beam  8  centered on a scribed centerline  20   d  which is substantially in line with reference line  4  on the plumb bob  20   a .  FIG. 4 b    shows the laser beam  8  off center of the plumb bob  20   a  as seen by the distance of the vertical element of the beam  8  cross from the centerline  20   d . It may be noted that the target  20  may be used on the belt edge  4  on either or both sides of the idler in or opposite the belt direction  5  to more precisely establish an initial position for the laser  7  and its beam  8  by increasing the distance between locations  29   a  and  29 . The difference between  FIG. 4 a    and  FIG. 4 b    illustrates the aligned and misaligned idler cases if the laser beam  8  is initially set to the position shown in  FIG. 3 . 
         [0038]    Whereas the belt in a conveyor belts is a continuous loop, and the belt described above moves in direction  5 , the same belt is running in the opposite direction  5   a  under the previous belt  1  as shown in  FIG. 5  but is called here the return belt  24 . As before, the return belt  24  has edges  25  that are parallel to the movement direction  5   a . The return belt  24  may be supported by regularly spaced idler rolls  21  which in turn are supported by brackets  22  bolted to support structure  9  comparable or the same as described previously. The return belt may also be supported by multiple roll sets but the use of the preferred embodiment is similar so is not described here.  FIG. 5 a    shows a close up of the brackets  22  supporting the return belt roll  21 . The brackets  22  are again clamped to the support structure with bolts and nuts  26  in slots  27 . As with the carrying idler frames  3  ( FIG. 1 a   ) and its relationship to its rolls  6 ,  12  and its slots  10 , the slots  27  allow angular adjustment of the return idler  21  axis. 
         [0039]      FIG. 5 b    shows the preferred embodiment hanging from the return idler roll  21  due to the attraction of its magnets  15  again with its tube  13  parallel to the attached roll  21 . In this case, the preferred embodiment is positioned to be approximately directly under the roll  21  so the support from the prop  18  is not needed.  FIG. 5 c    is another view of the preferred embodiment hanging from the return idler roll  21 . Laser  7  and its beam  8  is shown lined up with belt edge  25 , as was seen in  FIG. 3 , by sliding bar  16  in tube  13 . The stop  17  is adjusted to abut the tube  13  establishing an initial position for the belt edge  25  upstream relative to the belt direction  5   a .  FIG. 5 d    shows the same preferred embodiment placement on the same roll  21  but with the bar  16  and its attached laser  7  assembly rotated to point downstream of belt movement  5   a . Any two rotary positions and locations on  25  as illustrated in  5   c  or  FIG. 5 d    may be used as  29   a ,  29   b ,  29   a  and  29   b  to indicated alignment. 
         [0040]    The laser beam may or may not be centered per  FIG. 3  but in either case provides information as before to improve the perpendicularity of roll  21  to the belt direction  5   a  by moving one of the brackets  22  in the slots  27 . The spacing of idlers  21  are typically wider that with the carry side so using the target  20  for better precision is not as important but nonetheless, may be used as described above. 
         [0041]      FIG. 6  shows the laser  7  and laser beam  8  rotated to used one of the edges of a common version of the conveyor support structure as a reference line  4   b  instead of the belt edge  4 . 
         [0042]      FIG. 7  shows use of another alternate to the reference line  4  by installing a tight wire  4   a  or another laser beam  4   a  mounted to be parallel to the belt movement direction  5 . 
         [0043]    Accuracy of assembly shown in  FIG. 2  is essential to the purpose of the present invention which will be referred to as an alignment verification rig (AVR). It was developed using precisely cut parts, close telescoping shaft  16  and tube  13  fit, jig alignment of both V plates  14  or pairs of plates to the tube  13  before fixing to each other and precision machined mounting block  7   b  fixing the laser  7   a  to the shaft  16  end are important elements to obtaining this accuracy. The length of the tube  16  and spacing of the V plate  14  pairs should be almost as long as the center roll  12  for best tube  13  and shaft  16  parallelism accuracy to the roll axis  12   a . Use of a laser  7   a  constructed to allow fine tuning adjustment allows additional accuracy after assembly of the AVR. 
         [0044]    The precisely parallel axial mounting providing purely radial movements of the perpendicular pointer  8  or  8   a  allowed by the configuration of this device to locate the conveyor belt edge  4  at various points along its length are believed to be novel. This construction allows the use of a less expensive laser. Using magnetic attraction to easily and precisely attach a measurement device to an idler is believed to be novel, though other ways of attaching the device to the idler roller tube such as straps, vacuum, or the like can be used instead. The ease of use and lower cost in addition to allowing attachment with the belt installed are advantages. 
         [0045]    The preferred embodiment of the AVR, the details of which are not critical unless they are covered by the broadest appended claims, comprises a tight fitting telescoping combination of a shaft in a tube allowing axial movement and rotation. The tube is fixed to a pair of identical plates or pairs of plates which each have V notches that are aligned parallel to the tube so to engage the outer diameter of an idler roll, usually the center roll. The outer profile of the plates is such that they do not interfere with the horizontal belt contacting the roll at twelve o&#39;clock when located in an approximately three o&#39;clock position. 
         [0046]    Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the spirit and scope of the preferred embodiment, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept as expressed by the attached claims.