Patent Abstract:
The beads of a beaded conveyor belt for a curve conveyor are constituted by a number of bead constituting bodies ( 2   b ) that are disposed over the entire periphery of the outer surface along the outer peripheral edge of a belt main body ( 2   a ) and that are narrow in the direction of the length of the belt. Further, the beads of a beaded conveyor belt for a liner conveyor are constituted by a number of bead constituting bodies ( 7   b ) that are disposed over the entire periphery of the outer surface along opposite side edge of a belt main body ( 7   a ) and that are narrow in the direction of the length of the belt. The conveyor belt is installed taut between straight type end rollers ( 15 ), and the width of the bead constituting bodies ( 2   b   , 7   b ) lengthwise of the belt is set at about 20–60% of the diameter of the straight type end rollers ( 15 ). Even when the conveyor belt is installed taut between small-diameter end rollers, long-term use is possible.

Full Description:
CROSS-REFERENCE TO PRIOR APPLICATION 
   This is a divisional application of U.S. application Ser. No. 10/476,031, filed Oct. 23, 2003 which claims the benefit of priority of a U.S. National Phase Application under 35 U.S.C. §371 of International Patent Application No. PCT/JP02/04502 filed May 8, 2002, and claims the benefit of Japanese Patent Application No. 2001-141521 filed May 11, 2001 which are incorporated by reference herein. The international application was published in Japanese on Nov. 21, 2002 as WO 02/092476 a1 under pct article 21(2). 

   FIELD OF THE INVENTION 
   The present invention relates to a conveyor belt with bead used in a curved conveyor or a straight conveyor. 
   PRIOR ART 
   A curved conveyor, as illustrated in  FIG. 14 , is generally formed by stretching a conveyor belt  90  between end rollers  92  and  92  disposed rotatably at a certain angle and provided on a conveyor body  91 . The conveyor belt  90  is shown in  FIG. 15 . A urethane rubber bead  93  is sewed together with the outer hem area. In order to prevent the inward shift due to the centripetal force during the rotation, the bead  93  is engaged with a guide members  94  attached to the conveyor body  91 . The guide member of this type is generally disposed as shown in  FIG. 15 . A pair of bearings BR and BR is attached to a block B in a fashion that they are symmetrically inclined with respect of the horizontal plane. And a thick portion  93   a  of the bead  93  is held between the bearings BR and BR. 
   During the rotation of this conveyor belt, the bead  93  is affected by bending force at the time of configuration change along with the outer peripheral configuration of the end roller  92 , and thereby causing crack and/or breakage on the thick portion  93   a  of the bead  93  in a relatively short time period. The smaller the diameter of the end roller  93  is, the more conspicuous occurrences of such crack and/or breakage are. The occurrence of crack and/or breakage of the bead means destruction of the conveyor belt  90 . 
   In a straight conveyor in which beads are sewed to both hem sides for prevention of meander of the belt, if the end roller has a small diameter, crack and/or breakage will occur in a relatively short time period. 
   Therefore in the field handling conveyor belts of this type, there has became a serious demand for a conveyor belt with bead in which crack and/or breakage of beads will not occur for a long time period even if a conveyor belt is stretched between small diameter end rollers, and which will withstand the use for a long time period. 
   Therefore, it is an object of the present invention to provide a conveyor belt with bead which may be usable for a long time period even if a conveyor belt is stretched between small diameter end rollers. 
   SUMMARY OF THE INVENTION 
   An aspect of the present invention is a conveyor belt with bead for a curved conveyor having a belt body and a bead member. The belt is stretched between two small-diameter straight end rollers disposed at a certain angle, and the bead member is formed with a plurality of narrow bead composing elements which are disposed along an entire peripheral edge portion of the belt body. The width of each bead composing elements in a forwarding direction is as narrow as 20 to 60% of the straight end rollers. 
   Another aspect according to the present invention is a conveyor belt with bead for a straight conveyor having a belt body and a bead member. The belt is stretched between two small-diameter straight end rollers disposed in parallel, and the bead member is formed with a plurality of narrow bead composing elements which are disposed along entire edge portions at both sides of the belt body. The width of each bead composing elements in a forwarding direction is as narrow as 20 to 60% of the straight end rollers. 
   Any adjacent bead composing elements of the bead member may be disposed separately, or connected through a thin piece. 
   Furthermore, each of the bead composing elements may have a thick portion for preventing inward shift of the belt body by engaging with a bar guide member provided on the body of the conveyor. 
   The small-diameter end roller may have a diameter of about 15 to 30 mm. 
   The above and other objects, features and advantages of the present invention will be apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a plan view of a curved conveyor employing a conveyor belt with bead according to an embodiment of the present invention; 
       FIG. 2  is a sectional view taken along line X—X of  FIG. 1 ; 
       FIG. 3  is a bottom view of the belt conveyor; 
       FIG. 4  is a view showing a state in which the conveyor belt with bead is stretched between the end rollers in the belt conveyor; 
       FIG. 5  is a sectional view showing a relation between a bead composing element and a shift prevention member employed in the belt conveyor; 
       FIG. 6  is a plan view of a sheet for forming a belt body; 
       FIG. 7  is a perspective view of the conveyor belt with bead; 
       FIG. 8  is a sectional view showing a state in which a bead composing element is attached on the belt body; 
       FIG. 9  is a sectional view showing another method for attaching bead composing elements on the belt body; 
       FIG. 10  is a sectional view showing another method for attaching bead composing elements on the belt body; 
       FIG. 11  is a sectional view showing another method for attaching another bead composing element on the belt body; 
       FIG. 12  is a plan view of bead composing elements according to another embodiment; 
       FIG. 13  is a plan view showing a state in which bead composing elements are provided on both sides of a straight conveyor belt; 
       FIG. 14  is a plane view of a conventional curved conveyor; and 
       FIG. 15  is a sectional view of  FIG. 14  taken along the line Y—Y. 
       FIG. 16  is a perspective view of the width of a bead composing element relative to the straight end roller. 
       FIG. 17  is a sectional view showing a state in which a bead composing element is attached on the belt body and to other bead composing elements. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a plan view of a conveyor C which employs a conveyor belt  2  with bead according to this invention.  FIG. 2  is a sectional view taken along the line X—X in  FIG. 1 , and  FIG. 3  is a bottom view of the conveyor C. 
   A basic constitution of this conveyor C is shown in  FIGS. 1 to 3 . The conveyor C includes a conveyor main body  1 , a conveyor belt  2  with bead (hereinafter sometimes referred to as “beaded conveyor belt”) stretched on the conveyor main body  1 , a shift prevention member  3  for preventing the beaded conveyor belt  2  from shifting inwardly, a driving member  4  for rotationally driving the beaded conveyor belt  2 . The conveyor C also includes a cover member  5  which covers a motor  40  with a decelerator for the driving member  4 , the shift prevention member  3  on the upper side and an inner and an outer peripheral portion of the beaded conveyor belt  2 , and a leg member  6  which keeps the conveyor main body  1  at a suitable height. These main parts of the conveyor C will be described in detail below. 
   The conveyor main body  1 , as shown in  FIG. 1 , includes a motor support element  1   a , and a belt support element  1   b  bolted to the motor support element  1   a.    
   As shown in  FIGS. 2 and 3 , the motor support element  1   a  is composed of a motor mounting plate  10  and a base plate  11  provided on the upper end of the leg member  6 , and formed in an L-shape in a side view. The base plate  11  has bracket portions  12  at both end portions thereof. The motor mounting plate  10  has a unit mounting plate  13  in the side of the belt support element  1   b.    
   As shown in  FIGS. 1 ,  3  and  4 , the belt support element  1   b  includes a belt mounting plate  14  and two belt guide plates  16  and  16  which are fixed with a lower face of the belt mounting plate  14  through brackets. As clearly seen in  FIG. 2 , the belt mounting plate  14  is bolted to the bracket portion  12 . The belt mounting plate  14 , as clearly seen in  FIG. 1 , is formed in a pentagonal shape in a plan view. Bent pieces  14   a  and  14   a  provided at an angle of 90 degrees respectively receive straight end rollers  15  and  15  having a diameter of approximately 15 to 30 mm. As shown in  FIGS. 1 and 3 , the end roller  15  includes a stainless steel axial piece  15   a  bolted to the bent piece  14   a  and plural resin rollers  15   b  are attached rotatably on the axial piece  15   a . A bearing  15   c  (which has the same diameter as or a little larger diameter than the outer diameter of the roller  15   b ) is interposed between the resin rollers  15   b  and  15   b  provided near the outer peripheral side of the belt. 
   The conveyor belt  2  with bead is illustrated in  FIGS. 1 and 7 . It includes a belt body  2   a  and a number of bead composing elements  2   b  disposed across an entire outer peripheral end of the belt body  2   a . Each bead composing element  2   b  has a narrow width. 
   The belt body  2   a  has a polyester sail cloth as a core body thereof and a thermoplastic polyurethane as a surface material of a conveying face. Both ends of a fan-shaped sheet are joined to make a tapered tube shape as shown in  FIG. 7 . In general, the belt body  2   a  of this type is formed by joining both the ends of the fan-shape by a skiving joint or a step joint. This causes to increase the manufacturing cost, the number of the manufacturing steps and the thickness of the joining part. In order to prevent these drawbacks, here in the present invention, the belt body  2   a  is manufactured in the following manners (1) and (2): 
   (1) As shown in  FIG. 6 , a sheet S which has a polyester sail cloth as a core body and a thermoplastic polyurethane as a surface material of a conveying face is punched out into a fan shape with a Thompson blade. The sheet punched as such has radial end portions to be joined together. Each of the end portions is formed in a series of finger-like protrusions extending from the inner peripheral end up to near the outer peripheral end, and each of fingers or finger-like protrusions has a narrow angle tip (an angle α 1  between a cut line L 1  of the finger and a contact line L to the belt peripheral direction line is small). The part from the portion to be caught and held by the driving roller  41  and the pinch roller  42   a  and the vicinity thereof up to the outer peripheral end is formed with one cut line L 2  having a large angle α 2  with respect to the contact line L to the belt peripheral direction line. Furthermore, as shown in  FIGS. 6 and 8 , a number of through holes h 1  and h 2  for attaching a number of bead composing elements  2   b  are provided near the outer peripheral end of the belt body  2   a  of the sheet S. 
   The sail cloth and the surface material of the sheet to form the belt body  2   a  are not limited to the above. The cut line L 2  may be curved. 
   (2) The end portions of the sheet S to be joined together are meshed with each other as shown in  FIG. 7 . And a urethane sheet is applied on the thermoplastic polyurethane on the finger jointed part and heat and pressure are applied thereon. In consequence, urethane of the urethane sheet is melt to infiltrate into gaps present between the joining edges, so that the ends of the sheet S are joined together. 
   The bead composing element  2   b , illustrated in  FIG. 8 , includes a rectangular plate portion  20  and a thick portion  21  (or a projecting portion) provided on a longitudinal center portion of the plate portion  20  which has a substantially trapezoidal shape in a side view, and the portions  20  and  21  are integrally formed with synthetic resin or sintered metal. The plate portion  20  has an engaging part  20   a  at one side and an engaging hole  20   b  at the other side. When the bead composing element  2   b  is attached on the belt body  2   a , the engaging part  20   a  is fit into the through-hole h 2 , while a pin  22  is fit into the through-hole h 1  and the engaging hole  20   b , so that the bead composing element  2   b  is fixed with the belt body  2   a . Here, in the bead composing element  2   b , for example, the plate portion  20  may have an 8.5 mm width in the forwarding direction at the outer peripheral edge side of the belt, an 8 mm width in the inner peripheral edge side thereof, and a length of 30 mm. Furthermore, the thick portion  21  may have a height of 4 mm and the side face thereof has a 70° inclination angle. 
   The way of attaching the bead composing element  2   b  to the belt main body  2   a  is not limitative to the above. As shown in  FIGS. 9 and 10 , the bead composing element  2   b  may be attached thereto with a thread K through a hole  23  formed on the bead composing element  2   b . Furthermore, a pressed plate structure as shown in  FIG. 11  may be used as the bead composing element  2   b . In this bead composing element  2   b , a steel plate is bent to make a slant surface  25  which is in contact with the guide members  30 ,  31  and  31 . This pressed plate structure is attached to the belt main body  2   a  with a claw  26  which bites down the belt body  2   a.    
   The bead composing element  2   b  may be applicable if the width in the belt forwarding direction is as approximately 20 to 60% narrow as the diameter of a straight end roller which has a small diameter. 
   The adjacent bead composing elements  2   b  and  2   b  may be mutually joined together through an elastic bentable thin piece  20   c  (integrally formed), as shown in  FIG. 12 . 
   Then, the bead composing element  2   b  may be detachable from the belt body  2   a  as described above, or may also be fixed thereto. 
   The shift prevention member  3  is clearly illustrated in  FIGS. 1 and 3 . The shift prevention member  3  includes an upper side guide member  30 , lower side guide members  31  and  31 , a press member  32  and a screw  33 . The press member  32  presses the upper side guide member  30  and the lower side guide members  31  and  31  against the slant surface of the thick portion  21  of the bead composing element  2   b . The screw  33  is manually used for fixing the press member  32  with the upper side of the belt mounting plate  14  and the lower side of the belt guide plates  16  and  16 . 
   The upper side guide member  30 , shown in  FIGS. 1 and 5 , is provided on the upper side of the belt mounting plate  14  to prevent the inward shift of the belt. The upper side guide member  30  is formed of a round bar having shortly tapered ends at the both ends, and shaped in an arc as a whole with a curvature radius to contact with the inner side slant face of the thick portion  21 . 
   The lower side guide members  31  and  31 , as shown in  FIG. 3 , is located on the under side of the belt guide plate  16  to prevent the inward shift of the belt. The lower side guide members  31  and  31  are made of round bars with shortly tapered ends and formed in an arc shape with a curvature radius to contact with the inner side slant face of the thick portion  21 . The guide member, here, is divided in two  31  and  31 , different from the upper side guide member. This is because the driving roller  41  and the pinch roller  42   a  are located there, as shown in  FIG. 3 . 
   The material of the upper and lower guide members  30 ,  31  and  31  is determined with respect to the material of the bead composing element  2   b . One of the former and the latter is synthetic resin, then the other of them must be metal. On the other hand, if one of them is sintered metal, the other may be metal. 
   The press member  32  is, as illustrated in  FIG. 5 , provided with a groove  32   a  with an arc section.  FIG. 5  shows only the upper side guide member  30  and other parts therearound, however, the lower side guide members  31  and  31  and other parts therearound also have the same structure. The upper side of the upper guide member  30  and the lower sides of the lower guide members  31  and  31  are respectively received within the grooves  32   a  so that the guide members  30 ,  31  and  31  are positioned to stay therein in contact with the inner slant face of the thick portions  21 . 
   The screw  33  is formed with a male screw fixed with a manually rotatable portion of a large diameter on one end. The upper side and the lower side guide members  30 ,  31  and  31  may be easily removed from the beaded conveyor belt  2  without using a tool, but only by grabbing and rotating the manually rotatable portion of the screw  33 . 
   The driving member  4 , as shown in  FIGS. 1 to 3 , includes a motor  40  with a decelerator, the driving roller  41 , the pinch roller unit  42  and a controller (not shown). The motor  40  is bolted together to the mounting plate  10  of the motor supporting member  1   a . The driving roller  41  is attached on the output shaft of the motor  40  with the decelerator. The pinch roller unit  42  is attached on the unit mounting plate  13 . The controller is to change the rotation of the output shaft of the motor  40  with the decelerator by changing the frequency. 
   The pinch roller unit  42 , as shown in  FIGS. 2 and 4 , holds the beaded conveyor belt  2  between the pinch roller  42   a  and the driving roller  41  to reliably rotate and drive the beaded conveyor belt  2  by the friction engagement. This pinch roller unit  42  is constituted so as to adjust the force for holding the beaded conveyor belt  2  between the pinch roller  42   a  and the driving roller  41 . Separation of the pinch roller  42   a  from the driving roller  41  allows to release the holding engagement of the beaded conveyor belt  2 . 
   The motor  41  with the decelerator, the driving roller  41  and the controller are already known, and will not be described here in detail. 
   The cover  5  includes, as shown in  FIGS. 1 and 2 , an inner peripheral side cover  5   a  and an outer peripheral side cover  5   b.    
   The inner peripheral side cover  5   a , as shown in  FIG. 1 , is formed in a fan shape so as to cover the inner peripheral edge area of the beaded conveyor belt  2  and the vicinity thereof. The cover  5   a  is screwed together to an upper portion  61   a  of the leg member  61  through a manually rotatble cover attaching screw  50  as shown in  FIG. 2 . 
   The outer peripheral side cover  5   b , as shown in  FIG. 1 , is shaped so as to cover the outer periphery edge area of the beaded conveyor belt  2  and the vicinity thereof, i.e., formed in a shape to cover the bead composing elements  2   b , the upper guide member  30 , the press member  32 , the screw  33 , the motor  40  with the decelerator, the controller and the like. The cover  5   b  is attached to the vertical part  14   b  of the belt mounting plate  14  through a manually rotatable cover attaching screw  50 . 
   The leg member  6 , as shown in  FIGS. 2 and 3 , includes a leg portion  60  in an up-side-down T-shape formed by fixing a pillar  60   a  to the center of a horizontal beams  60   b , a leg portion  61  of one pillar, a horizontal beam  62  connecting the leg portion  61  and the pillar  60   a , and foot portions  63 ,  63  and  63  with height adjustable screws attached on the both ends of the horizontal beam  60   b  and the bottom portion of the leg portion  61 . The outer side portion of the belt having the motor  40  with the decelerator and the like is supported by the leg portion  60 , while the inner side portion of the belt on the belt mounting plate  14  is supported by the leg portion  61 . 
   Here, when the cover attaching screw  50  is removed, the upper portion  61   a  of the leg portion  61  can be rotated down with a hinge T. 
   The conveyor belt  2  with bead is attached to the conveyor body  1  as follows. 
   As shown in  FIG. 4 , the beaded conveyor belt  2  is stretched between the end rollers  15  and  15  so as to maintain a certain rotation track by the belt mounting plate  14 , the two belt guide plates  16  and  16 , the driving roller  41  and the pinch roller  42   a.    
   Furthermore, as described above, the conveyor belt  2  is stretched between the end rollers  15  and  15 , and, in this state shown in  FIGS. 1 ,  3  and  5 , the inner slant faces of the thick portions of a number of bead composing elements  2   b  (function as a bead member) on the belt  2  are in contact with the upper and lower guide members  30 ,  31  and  31 . 
   Therefore, when the motor  40  with the decelerator is driven, the beaded conveyor belt  2  rotates as being caught and held between the driving roller  41  and the pinch roller  42   a . And the bead composing elements  2   b  forward sliding on the upper and lower side guide members  30 ,  31  and  31  in the above mentioned contact state therewith. Consequently, the conveyor belt  2  is prevented from inward shifting. Namely, the bead member composed of a number of bead composing elements  2   b  exhibits the same function as a continuously formed bead. 
   The beaded conveyor belt  2  may be removed from the conveyor main body  1  with the following steps (1) to (5). 
   (1) Release the manually operable screw  50  for mounting the cover, and remove the inner side cover  5   a  and the outer side cover  5   b    
   (2) Rotate down the upper portion  61   a  of the leg member  61  with the hinge T from a position shown by continuous line to another position shown by two-dot chain line in  FIG. 2   
   (3) Loose the manually operable (rotatable) screw  33  to remove the upper and lower guide members  30 ,  31  and  31  received within the groove  32   a  from the press member  32   
   (4) Separate the pinch roller  42  away from the driving roller  41  to release the conveyor belt  2  being held therebetween 
   (5) After the above steps (1) to (4), shift the beaded conveyor belt  2  inwardly (from the outer peripheral side toward the inner peripheral side) so that the beaded conveyor belt  2  may be removed from the conveyor main body  1   
   (6) When attaching the beaded conveyor belt  2  on the conveyor main body  1 , take the above steps reversely. 
   As stated above, in the constitution of this beaded conveyor belt  2 ; (1) the bead member is composed of a number of bead composing elements  2   b  disposed on across the entire outer peripheral area of the belt main body  2   a , (2) the width (in the belt forwarding direction) of each bead composing element  2   b  is as narrow as about 20 to 60% of the diameter of the straight end roller  15  having a small diameter, and (3) the adjacent bead composing elements  2   b  and  2   b  are separated from each other, or are connected with a thin piece  20   c . Therefore, compared with the conveyor belt with bead in the prior art section, in this conveyor belt  2  with bead, extremely less crack and/or breakage may occur in the beat composing elements  2   b , and thereby the belt  2  withstand the long time use. 
   Alternatively, for example, in case bead composing elements  2   b  are pinned or sewed together with the belt body  2   a , when one or some of the bead composing elements  2   b  are damaged, the one or some of them may be easily replaced. That is, even if one or some of the bead composing elements  2   b  are damaged, the conveyor belt may be continuously used only by replacing the damaged bead composing elements  2   b.    
   Advantageous features of the belt body  2   a  are described below. 
   The joint portion (i.e. a radial end portion of the fan-shaped sheet S) is formed by one time press cut with a Thompson blade, and this allows a small number of manufacturing steps and a low manufacturing cost. 
   Furthermore, the belt body  2   a  has a finger joint from the inner peripheral end to near the outer peripheral end, and the other area from the portion to be held between the driving roller  41  and the pinch roller  42   a  and the vicinity thereof up to the outer peripheral end is a joint of straight cut lines L each of which has a large angle α 2  with respect to the contact line L on the peripheral direction line of the belt. Therefore, twisting load due to the change in the peripheral speed by the driving roller  41 , the belt body  2   a  and the pinch roller  42   a  and inwardly shifting force of the belt body  2   a  may be prevented by the shift prevention member  3 . And, as a result, even if pull force in a width (radial) direction of the belt body  2   a  is occurred, detachment and breakage hardly occurs at a portion indicated with the numeral  27  of the belt body  2   a.    
   The end portions of the fan-shaped sheet S are practically joined together with a finger joint, and the joined portion will not become thicker like those in the skiving joint or the step joint. 
   The effects of using the end roller  15  are as follows. The end roller  15 , as shown in  FIG. 1 , is formed with the axial piece  15   a  and a plurality of resin rollers  15   b  rotatably provided thereon. And the bearing  15   c  (which has the same diameter as or a larger diameter than the outer diameter of the resin roller  15   b ) is provided between the adjacent resin rollers  15   b  and  15   b  located on the belt outer peripheral side. Therefore, in the outer peripheral area of the belt where the peripheral speed of the belt body  2   a  is rather large, the belt body  2   a  forwards along with the rotation of the outer lace of the bearings  15   c , while in the inner peripheral area of the belt where the peripheral speed of the belt body  2   a  is small, the belt body  2   a  forwards along with the rotation of the resin rollers  15   b . Therefore, in the outer peripheral area with a larger peripheral speed, harsh friction noises may be extremely suppressed as compared with the case using end rollers having no bearings  15   c , or eliminated. 
   In the above embodiment, the aspect of the present invention is applied to a curved conveyor belt; however, this is not limitative thereto. Another embodiment is shown in  FIG. 13  in which an aspect of the present invention is applied to a straight conveyor. A belt body  7   a  of the straight conveyor has a plurality of bead composing elements  7   b , which have a similar structure to that of the above mentioned bead composing elements  2   b , at both ends. Straight guide members  70  and  70  are disposed on the conveyor body and are in contact with the inside slant faces of thick portions  71  and  71  of the bead composing elements  7   b  and  7   b . In this structure, not only meander forwarding of the bolt body  7   a  may be prevented, but also, if one or more of the bead composing elements  7   b  are damaged, replacement of the damaged bead composing elements and restoration of the system could be easily done. 
   In the foregoing embodiments, the thick portions  21  and  71  of the bead composing elements  2   b  and  7   b  are shaped in a trapezoid in a side view. The shape is not limitative thereto, but may be rectangular, square, triangle or the like. 
   Having the construction stated above, the present invention may provide a conveyor belt with bead which may be used for a long term period even if the belt is stretched between small diameter end rollers.

Technology Classification (CPC): 1