Patent Abstract:
A belt conveyor includes at least one belt module defined by at least one drive pulley and at least one other pulley that is generally an idler pulley positioned between opposite sidewalls of the conveyor, and having a continuous belt routed around the drive pulley and the other pulley. The drive pulley is operable to drive the continuous belt around the pulleys to move articles along the zone assembly. The belt conveyor may incorporate features that allow for improved maintenance methods and reduced down time during service intervals. These features may include a removable belt module, at least one pulley mounted on at least one pivot arm, or a combination thereof. The belt may have a low modulus characteristic and may be initially stretched when the belt is reeved or routed around the pulleys and the pivot arms are moved into their operating position.

Full Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present invention claims the benefit of U.S. provisional application Ser. No. 60/826,788, filed Sep. 25, 2006, which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to material handling conveyors and, more particularly, to belt conveyors. 
     BACKGROUND OF THE INVENTION 
     It is known to provide zones of belts along a belt conveyor, where each zone consists of a zone assembly that includes a powered roller and at least one additional roller, such as and idler or freely rotating roller, having a continuous belt reeved around the rollers. However, typical belt conveyors require extensive disassembly to perform maintenance tasks such as replacing a belt, replacing a roller, lubricating bearings, or the like, rendering the entire belt conveyor unusable while maintenance is performed. 
     SUMMARY OF THE INVENTION 
     The present invention provides a belt conveyor, removable belt module, and method of replacing a continuous belt in which the belt may be rapidly replaced. 
     According to one aspect of the present invention, a removable belt module is provided for use with a conveyor having a frame assembly and a stationary motor mounted to the frame assembly. The removable belt module includes a removable belt module frame, a drive pulley, at least one other pulley, a continuous belt, and a power transmission device. The removable belt module frame is supportable at the frame assembly of the conveyor. The drive pulley and other pulley are each rotatably mounted at the removable belt module frame. A continuous belt is reeved around the drive pulley and the other pulley. The power transmission device interconnects the drive pulley with the motor to drive the continuous belt. 
     According to another aspect of the present invention, a belt conveyor includes a frame assembly supporting at least one zone assembly that includes a removable belt module. The removable belt module has a removable belt module frame, a drive pulley, at least one other pulley, and a continuous belt. The drive pulley and other pulley are rotatably supported by the removable belt module frame. The continuous belt is reeved around the drive pulley and the other pulley. The removable belt module is vertically separable from the zone assembly in order to facilitate the replacement of the removable belt module and/or the continuous belt. Thus, the continuous belt may be replaced according to a method whereby the removable belt module is removed from the frame assembly in a substantially vertical direction and a replacement removable belt module is positioned at the frame assembly in a substantially vertical direction. 
     According to yet another aspect of the present invention, a belt conveyor includes a frame assembly having opposite sidewalls, a drive pulley, at least one other pulley, a continuous belt, and at least one pivot arm. The drive pulley and the other pulley are rotatably mounted at the frame assembly between the opposite sidewalls. The continuous belt is reeved around the drive pulley and the other pulley. The drive pulley, the other pulley, or both the drive pulley and the other pulley are rotatably mounted to the frame assembly by the pivot arm. The pivot arm pivots from an operating position to a maintenance position to move the drive pulley and the other pulley closer together to facilitate replacement of the belt. The pivot arm pivots from the maintenance position to the operating position to place tension on the belt when the pivot arm is in the operating position. Thus, the continuous belt may be replaced according to a method whereby the pivot arm is moved away from the operating position such that said pulleys release said belt tension, the continuous belt is removed from the drive pulley and the other pulley, a replacement continuous belt is reeved around the drive pulley and the other pulley, and the pivot arm is moved back to the operating position such that the pulleys impart tension to the replacement continuous belt. 
     According to still other aspects, any of the above aspects of the present invention may include one or more fasteners for connecting the removable belt module to a conveyor. The fasteners may be accessible from the top or side of the conveyor. The electric motor may be adjustably supported by the frame assembly and further attached to the drive pulley via a rotary power transmission device such as a cog belt, a v-belt, a chain, a driveshaft, a gear train, or the like. Where the electric motor is adjustably supported, a mechanism such as a jackscrew may be provided for adjusting the position of the motor to aid in removing the rotary power transmission device from the powered roller. The drive pulley may, alternatively, be driven by a combustion engine, a hydraulic or pneumatic motor, or like source of rotary power. The drive pulley may also be a self-driven motorized pulley. At least one of the drive pulley at one end of a given zone assembly, and the at least one other pulley at the opposite end of the zone assembly, may include a plurality of tracking devices operable to track the continuous belt that is reeved around the drive pulley and the at least one other pulley. These devices may comprise strips or crowns around the respective pulleys. A fastener such as a bolt, a latch, or other device may be used to fix the pivot arms in the operating position. 
     According to further aspects, the continuous belt may comprise a low modulus characteristic of the type disclosed in commonly assigned U.S. Pat. No. 6,811,018, which is hereby incorporated herein by reference. The use of a low modulus characteristic continuous belt as a conveying surface facilitates the use of an over-center pivot arm by allowing approximately 0.75% or more stretch to the continuous belt during movement of the pivot arms from a slack or maintenance position to the operating position. The drive roller may be lagged to create a high-friction interface between the drive roller and the continuous belt. The continuous belt may have a width that spans substantially across the space between the sidewalls of the conveyor frame assembly. Attachment surfaces, such as mounting blocks, may be provided at the frame assembly for supporting the removable belt module. Two or more zone assemblies or removable belt modules may be arranged in tandem to provide an elongated conveyor. A slider plate may be provided between the drive roller and the other roller to support the continuous belt therebetween. Alternatively, one or more additional rollers may be provided between the drive roller and the other roller to support the continuous belt. 
     Therefore, the present invention provides a conveyor having one or more removable belt modules that are readily removed or replaced at the conveyor. The removable belt module may include a pulley mounted via a pivot arm that is pivotable between an operating position and a maintenance position to facilitate the removal or replacement of a continuous belt at the module. 
     These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a multi-zone belt conveyor in accordance with an embodiment of the present invention; 
         FIG. 2  is a perspective view of a removable belt module; 
         FIG. 3A  is an end elevation of a tracking pulley useful with the present invention; 
         FIG. 3B  is an end elevation of a drive pulley useful with the present invention; 
         FIG. 4  is a cutaway side elevation of a single zone assembly and portions of a frame assembly; 
         FIG. 5  is a partial end elevation of the belt conveyor in  FIG. 4 ; 
         FIG. 6  is a cutaway partial side elevation of an interface between adjacent zone assemblies; 
         FIG. 7  is a perspective view of the belt conveyor in  FIG. 1  taken from the top and side thereof; 
         FIG. 8  is a perspective view of the belt conveyor in  FIG. 1  showing the other pulley in its operating position, and taken from the top and an opposite end thereof; 
         FIG. 9  is an enlarged perspective view of the area designated ‘IX’ in  FIG. 8 ; 
         FIG. 10  is the same view as  FIG. 8  showing the other pulley between its operating position and its maintenance position; 
         FIG. 11  is a perspective view of the removable belt module in  FIG. 2  showing the other pulley in its maintenance position, and taken from the bottom and end thereof; 
         FIG. 12  is a side elevation of the removable belt module in  FIG. 2  with the rotary power transmission device removed; and 
         FIG. 13  is an enlarged partial cutaway side elevation view of the area designated XIII in  FIG. 6 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings and the illustrative embodiments depicted therein, a belt conveyor  10  includes a frame assembly  16  supporting at least one zone assembly  15  ( FIGS. 1 and 4 ). Frame assembly  16  may include opposite sidewalls or side frames  14  and cross members  18 ,  18 ′ ( FIGS. 1 ,  4 , and  7 ), and may be supported from the floor or a platform, such as by frame legs (not shown), or by other structures such as wall-mount brackets, or chains, cables, or rods suspended from a ceiling (not shown). Zone assembly  15  includes a removable belt module  12 , a portion of sidewalls  14 , a rotary power transmission device  32 , a motor  22 , and an adjustment mechanism  20 . Removable belt module  12  is positioned between sidewalls  14 , and is operable to convey articles in a direction of conveyance illustrated by the arrow ( FIG. 1 ). In one embodiment, each removable belt module  12  includes a powered roller or drive pulley  24  and at least one other roller or pulley  26 , such as an idler pulley (shown) or another drive pulley, with a continuous belt  28  routed or reeved around pulleys  24 ,  26  ( FIG. 2 ). 
     Removable belt module  12  includes a removable belt module frame  30  having drive pulley  24  rotatably supported at one end and other pulley  26  rotatably supported at the other end ( FIGS. 2 ,  4 ,  6 ,  7 , and  13 ). In the embodiments shown, a slider plate  36  spans substantially the length of removable belt module frame  30  and lies just underneath and in sliding support of continuous belt  28  in the space between drive pulley  24  and other pulley  26 . In an alternate embodiment, slider plate  36  may be replaced by at least one spaced apart support pulley (not shown). In the embodiment depicted in  FIG. 4 , other pulley  26  is rotatably supported at removable belt module frame  30  by way of a pivot arm  38 , such as an over-center pivot arm  39 , as will be described in greater detail below. 
     Removable belt module  12  is removably supported by frame  16  between sidewalls  14  at one or more attachment surfaces  40  (see  FIGS. 1 ,  7 ,  8 , and  10 ). Attachment surfaces  40  can be mounting blocks  41  supported by sidewall  14  ( FIGS. 8 and 11 ), though any attachment surface designed to interface with removable belt module  12  can suffice. Fasteners  11  may be used to temporarily attach removable belt module  12  to attachment surfaces  40  (see  FIGS. 6 and 8 ). Fasteners  11  are readily accessible, such as from the top or side of the belt conveyor  10 , and may include at least one of threaded bolts (shown), latches, pins, tabs and slots, magnets, interference fit, or the like. Module  12  may be removed from frame  16  by raising or lowering module  12 , such as in a substantially vertical direction, after removing or disengaging fasteners  11 , for example. A plurality of removable belt modules  12  and zone assemblies  15  may be arranged in series to form an elongated conveying or buffering or gapping surface ( FIGS. 1 and 6 ). Where two or more removable belt modules  12  are arranged in series, a finger guard  43  may be installed at side walls  14  between adjacent belt modules  12  ( FIGS. 6 and 7 ). 
     Motor  22  and rotary power transmission device  32  are operable to drive removable belt module  12  ( FIGS. 5 and 6 ) or a traditional fixed belt module (not shown). Motor  22  is adjustably supported by adjustment mechanism  20 , which is supported by frame  16 , such as at cross member  18 . Motor  22  is connected to drive pulley  24  via rotary power transmission device  32 , which can be an endless belt (cog belt  33 , shown), a chain, a driveshaft, a gear train, or the like. In the illustrated embodiment, drive pulley  24  is depicted as having a cog pulley  34  ( FIGS. 3B and 6 ) attached thereon, to which cog belt  33  transmits power from motor  22  to drive pulley  24 . Continuous belt  28  is reeved around drive pulley  24  and other pulley  26 . In the illustrated embodiment, other pulley  26  is rotatably supported by pivot arm  38 , which is pivotally supported by removable belt module frame  30 . Other pulley  26  has a spindle  46  that is held fixed relative to pivot arm  38  by a clamp member  48  and a pair of fasteners  50  connecting clamp member  48  to pivot arm  38  ( FIGS. 6-13 ). 
     As shown in  FIG. 3A , one or both of drive pulley  24  and other pulley  26  (other pulley  26 , shown) has a cylindrical outer surface  26   a  that may be formed with at least one crown or bump  26   b  along the pulley. Crowns  26   b  assist in tracking belt  28  during operation of belt conveyor  10 . The use of crowns  26   b  in combination with a belt having a low modulus characteristic to track belt  28  is disclosed in commonly assigned U.S. Pat. No. 6,811,018, the disclosure of which is hereby incorporated herein by reference. Furthermore, drive pulley  24  may be lagged to create a high friction interface between drive pulley  24  and continuous belt  28  to drive belt  28  without slipping, and belt  28  preferably has a width that spans substantially across the space between sidewalls  14 . 
     Each zone assembly  12  may further include adjustment mechanism  20 , such as a jackscrew  21 , to temporarily move a motor axis  22 ′ closer to a drive pulley axis  24 ′ to adjust the tension on belt  33  so that cog belt  33  can be removed from drive pulley  24 , thus freeing removable belt module  12  from motor  22  ( FIG. 4 ). For embodiments in which a mechanism is desirable to move motor axis  22 ′ closer to drive pulley axis  24 ′ so that cog belt  33  can be removed, any mechanism that allows a rigid body to translate in at least one plane, while being temporarily fixable in at least one position, can provide that functionality. Jackscrew  21  is just one example of adjustment mechanism  20 , where other examples might include a T-pin and channel slider or a pivot arm device (not shown). 
     Alternative embodiments of the invention may be envisioned in which no adjustable motor mount is required, such as where the drive pulley comprises a motorized pulley. Another alternative embodiment that may not require an adjustable motor mount includes a gear train, or a splined shaft and gear train, as the rotary power transmission device. Yet another such alternative embodiment uses a drive pulley pivotally attached to either a removable belt module or a traditional fixed belt module such that the drive pulley&#39;s axis can be moved closer to the motor axis. Another such alternative embodiment uses a take-up assembly between the motor and drive pulley, and is disclosed in commonly assigned U.S. Pat. No. 6,860,383, the disclosure of which is hereby incorporated herein by reference. 
     While motor  22  is depicted herein as an electric motor located below removable belt module  12  and connected to drive pulley  24  via cog belt  33 , it will be appreciated that motor  22  represents any source of rotational power, whether separate from or internal to drive pulley  24 , including an AC motor, a DC motor, a combustion engine, a hydraulic or pneumatic motor, or the like. Also, the motor may be internal to drive pulley  24 , which is known in the art as a motorized pulley or motorized roller, as disclosed in commonly assigned U.S. Pat. No. 6,811,018. 
     Referring now to  FIGS. 8-11 , over-center pivot arm  39  allows slack or tension to be imparted to continuous belt  28  when belt  28  is supported by either removable belt module  12  or traditional fixed belt module (not shown). Two pivot arms  38  are typically employed at either drive pulley  24  or other pulley  26 , with one pivot arm  38  located at each end of the respective pulley. It is possible that a minimum of one pivot arm  38  could achieve the desired function. By moving pivot arms  38  such that the distance between drive pulley axis  24 ′ and other pulley axis  26 ′ is increased, continuous belt  28  is placed under tension such that belt conveyor  10  can be operated without belt  28  slipping on drive pulley  24  (see  FIGS. 2 ,  4 , and  6 - 9 ). 
     Depending on the configuration of pivot arms  38 , a fastener  13  may be used to fix pivot arms  38  in an operating position ( FIGS. 9 and 11 ). By moving pivot arms  38  to the maintenance position such that the distance between drive pulley axis  24 ′ and other pulley axis  26 ′ is decreased (see  FIGS. 10 and 11 ), enough slack is imparted to continuous belt  28  such that belt  28  can be removed from removable belt module  12  or traditional fixed belt module (not shown) by sliding continuous belt  28  off of drive pulley  24  and other pulley  26 . With pivot arms  38  in this position ( FIGS. 10 and 11 ), a replacement belt  28  may be installed and later made taut by moving the pivot arms  38  to the operating position to increase the distance between pulley axes  24 ′ and  26 ′ ( FIGS. 7-9 ). 
     In another embodiment of the invention, pivot arms  38  are configured as over-center pivot arms  39  (see  FIGS. 8-11 ). In the over-center configuration, over-center pivot arms  39  cause maximum tension to be imparted to an installed belt  28  when a line L 2  drawn from pivot axis  38 ′ to the respective pulley axis,  26 ′ or  24 ′, is collinear with a line L 1  drawn from drive pulley axis  24 ′ to other pulley axis  26 ′ (the “center” position).  FIG. 4  shows pivot arm  38  in the center position, while  FIGS. 8 ,  9 , and  13  show lines L 1 , L 2  at over-center pivot arm  39 . One or more stop members  42  can be used to allow pivot arms  39  to pivot past this center position (i.e., “over-center”) and come to rest against stop surfaces  42 ′ while still maintaining sufficient tension in continuous belt  28  so that belt  28  can be driven by drive pulley  24 , and pivot arms  39  are held in the operating position ( FIGS. 8-10  and  13 ). Though the pivot arms′  39  over-center position is stable with a continuous belt  28  installed, the illustrative embodiment depicts a fastener  13  ( FIGS. 9 ,  11 , and  13 ) employed to further fix pivot arms  39  in their over-center operating position. 
     The over-center position is stable because belt tension exerts a force F 1  on other pulley  26 , where force F 1  acts in a direction parallel to line L 1  and at a non-zero angle θ relative to line L 2  ( FIG. 9 ). Therefore, force F 1  has a component F 2  in the direction parallel to L 2 , and also a component F 3  in the direction perpendicular to L 2 . Force component F 3  thus urges pivot arm  39  into contact with stop surface  42 ′ of stop member  42 . It will be appreciated that pivot arms  38  ( FIG. 4 ) provide substantially the same function as over-center pivot arms  39 , but the configuration does not exhibit a vertical force component to hold pivot arms  38  in their operating position. 
     Changes and modifications in the specifically described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents.

Technology Classification (CPC): 1