Zone Actuated In-Line Dual Stack Roller Belt Conveyor
Patent Information
- Application Number
- JP2024547865
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-02-21
- Filing Date
- 2023-01-09
- Publication Date
- 2025-03-13
Smart Images
Figure 2025506662000001_ABST
Abstract
Description
[Technical field]
[0001] FIELD OF THEINVENTION This invention relates generally to power driven conveyors, and more particularly to belt conveyors having actuatable stack rollers. [Background technology]
[0002] Many conveying applications require articles to be spaced apart in the conveying direction. Smaller gaps between successive conveyed articles can improve throughput. It is also often important to separate side-by-side articles in the conveying direction so that they can meet downstream without collision. In some applications, it is also important to accumulate articles at low backline pressure until downstream processing is possible. Registration belts with actuated in-line rollers and pop-up flights, such as those described in U.S. Pat. No. 7,311,192, are used to space articles at set intervals. However, those registration belts are limited to article spacing that is fixed by the position of the flights. They cannot dynamically adjust the gap between successive articles, nor can they separate side-by-side articles. Furthermore, because articles on a registration belt are pushed forward against the flights by the actuated rollers and move with the belt, the residence time of the articles on the belt depends on the length of the belt and its speed. Summary of the Invention
[0003] One embodiment of a conveyor belt embodying features of the invention includes a plurality of cradles, each supporting at least one roller set. Each roller set includes a lower roller having a protruding portion that protrudes below a bottom surface of the belt, and a pair of upper rollers that form a support surface for conveyed articles. The lower and upper rollers are rotatable on an axis perpendicular to the direction of belt travel. When the lower roller is in contact with the upper roller, rotation of the lower roller in one direction causes the upper roller to rotate in the opposite direction. Each cradle is translatable from a first position in which the upper roller is at a first height level to a second position in which the upper roller is at a higher second height level and in contact with the lower roller.
[0004] One embodiment of a conveyor belt module embodying features of the invention includes a base and a roller assembly slidably mounted to the base. The base extends lengthwise from a first end to a second end and widthwise laterally from a first side to a second side. The base includes a bottom surface and a top deck, a first set of hinge elements spaced apart along the first end and a second set of hinge elements spaced apart along the second end, a cavity opening into the bottom surface and the top deck, and a boss on the top deck. The roller assembly includes at least one pair of side-by-side roller beds and a cradle having end supports at both ends of the roller beds, an upper roller in the roller bed, and a lower roller disposed in the cavity, having a protruding portion extending below the bottom surface, and having a lower roller axle. The upper roller axle is supported by the end supports and extends laterally through the upper roller to define a lateral axis of rotation for the upper roller. The cradle further includes an opening in the roller bed for the boss. When the lower roller is raised, it presses against the upper roller and the cradle is raised away from the upper deck so that the boss does not extend through the opening into the roller bed and rotation of the lower roller in one direction causes the upper roller to rotate in the opposite direction. When the lower roller is lowered, the cradle can rest on the upper deck and the boss can extend through the opening into the roller bed to abut the upper roller and brake it from rotating.
[0005] One aspect of a roller actuation assembly embodying features of the invention includes an actuator base and a bearing unit slidably mounted to the actuator base. The bearing unit includes a pair of bearing blocks having an upper bearing surface extending longitudinally in a first direction from a first end to a second end, an intermediate portion connected to the pair of bearing blocks and having an upper surface below the level of the upper bearing surfaces, and a wear strip support fixedly mounted to the actuator base above the upper surface of the intermediate portion of the bearing unit. An actuator mounted to the actuator base and coupled to the bearing unit moves the bearing unit between a lowered position and a raised position.
[0006] One aspect of a conveyor embodying features of the invention includes a conveyor belt and a plurality of roller actuation assemblies disposed below the conveyor belt. The conveyor belt includes a bottom surface and a plurality of roller assemblies disposed in lanes extending in a direction of belt travel. Each of the roller assemblies includes a lower roller having a protruding portion protruding below the bottom surface and a pair of upper rollers forming a support surface for conveyed articles. The lower and upper rollers are rotatable on an axis perpendicular to the direction of belt travel. When the lower roller is in contact with the upper roller, rotation of the lower roller in one direction causes the upper roller to rotate in the opposite direction. The conveyor belt also includes a cradle supporting the pair of upper rollers. The cradle and the lower roller are vertically translatable. The roller actuation assemblies are disposed below the conveyor belt. Each of the roller actuator assemblies is associated with one or more lanes of the roller assembly and each of the roller actuator assemblies includes one or more bearing surfaces extending lengthwise in the direction of belt travel beneath one or more lower rollers of the lane of the roller assembly, wear strip supports disposed beneath the bottom surface of the conveyor between the lower rollers of successive lanes, and actuators for moving the one or more bearing surfaces from a lowered position out of contact with the lower rollers of the associated lane to a raised position providing a surface against which the lower rollers of the associated lane can rotate in one direction and the upper rollers can rotate in the opposite direction as the conveyor belt advances in the direction of belt travel. The wear strips supported on the wear strip supports contact the bottom surface of the conveyor belt between the lower rollers of successive lanes.
[0007] Another embodiment of the conveyor belt includes a bottom surface, a plurality of cavities opening to the bottom surface, and a plurality of cradles. A lower roller is attached to each cavity and has an overhanging portion that overhangs below the bottom surface. The lower roller is translatable along the cavity. Each cradle supports two or more roller sets. Each roller set includes a pair of upper rollers that form a support surface for conveyed articles. The lower roller and the upper roller are rotatable on a laterally extending axis perpendicular to the direction of belt travel. The two or more roller sets are laterally spaced apart across the width of the conveyor belt. Each roller set is associated with one of the lower rollers. When a lower roller is in contact with an upper roller of the associated roller set, it rotates in one direction, causing the upper roller to rotate in the opposite direction. Each cradle is translatable from a first position in which the upper roller is at a first height level to a second position in which the upper roller is at a higher second height level and in contact with the lower roller.
[0008] Yet another embodiment of the conveyor belt includes a bottom surface, a plurality of cavities opening to the bottom surface, and a plurality of cradles. Each of the cradles supports one or more roller sets, each of which includes one or more upper rollers forming a support surface for conveyed articles and a lower roller having a protruding portion protruding from one of the cavities below the bottom surface. The lower roller is translatable along the cavity. The lower roller is rotatably mounted on a lower roller axle. An end of the lower roller axle is received for relative movement relative to the cradle. The lower roller and the one or more upper rollers are rotatable on an axis extending laterally perpendicular to the direction of belt movement. When the lower roller is in contact with the upper roller, rotation of the lower roller in one direction causes rotation of the upper roller in the opposite direction. Each cradle is translatable from a first position in which the upper roller is at a first height level to a second position in which the upper roller is at a higher second height level and in contact with the lower roller. [Brief description of the drawings]
[0009] [Figure 1]FIG. 1 is a perspective view of a conveyor belt module embodying features of the present invention. [Diagram 2] FIG. 2 is an exploded view of the conveyor belt module of FIG. [Diagram 3] FIG. 3 is a bottom view of the conveyor belt module of FIG. [Figure 4] FIG. 4 is a front view of the conveyor belt module of FIG. [Diagram 5] FIG. 5 is a perspective view of a roller cradle of a conveyor belt module such as that of FIG. 1, showing one of the upper and lower rollers removed. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 1, but with the rollers in a raised position. [Figure 8] FIG. 8 is a perspective view of a portion of a conveyor belt constructed from modules such as those of FIG. [Figure 9] FIG. 9 is a bottom view of the conveyor belt portion of FIG. [Figure 10] FIG. 10 is an isometric view of a conveyor path for a conveyor belt such as that of FIG. 8, showing the roller actuation assemblies. [Figure 11] 11 is an enlarged isometric view of a row of roller actuation assemblies in the transport path of FIG. [Figure 12] FIG. 12 is an isometric view of a roller actuation assembly like that of FIG. [Figure 13] 13 is an exploded view of the roller actuation assembly of FIG. [Figure 14] FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. [Figure 15] FIG. 15 is a cutaway side view of the conveyor belt of FIG. 8 showing its upper rollers stalled with lowered bearing surfaces. [Figure 16]FIG. 16 is a cutaway side view similar to FIG. 15, but showing the rollers operating with raised bearing surfaces. [Figure 17] FIG. 17 is an isometric view of a conveyor using a conveyor belt like that of FIG. 8 on a conveyor path like that of FIG. [Figure 18] FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. [Figure 19] FIG. 19 is a block diagram of a control system for the conveyor of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] 1-4 show a conveyor belt module embodying features of the invention. The module 20 includes a base 22 to which one or more (in this case two) roller assemblies 24 are attached. The roller assemblies 24 are snapped into place and have a limited range of vertical movement. Each roller assembly 24 has a cradle 26 that supports two roller sets 64, each including a vertically stacked, side-by-side pair of upper rollers 28 and a lower roller 30. However, a cradle with one roller set or three or more roller sets would be possible. Also possible are cradles with roller sets in which one upper roller is vertically aligned or slightly offset from the lower roller. In this embodiment, the base 22 and cradle 26 are made of a thermoplastic material, but in other embodiments they could be made of metal or other materials. The upper rollers 28 are arranged parallel within a roller bed 32 of the cradle 26. An upper roller axle 34 extends through a bore 36 in the upper roller 28. An upper roller axle 34 is supported by end supports 38 at the axial ends of each roller bed 32. The axles 34 define a lateral axis of rotation for the upper rollers 28 parallel to the width direction 40 of the module 20 such that the rollers rotate in a length direction 68. The lower rollers 30 of each stacked roller set 64 are suspended on the lower roller axle 42 below the upper roller bed 32 between a pair of legs 44 that extend downwardly from the bottom surface of the cradle 26. The distal ends 46 of the legs 44 terminate in tabs 48. The axial length of the lower rollers 30 is less than the axial length of the upper rollers 28, and the diameter of the lower rollers is greater than the diameter of the upper rollers in this embodiment. However, other belt configurations are possible in which the diameter of the upper rollers is at least as large as the diameter of the lower rollers.
[0011] The cradle 26 is snapped onto the base 22 by inserting the legs 44 through cavities 50 that open into the bottom surface 52 and top deck 54 of the base 22. The distal ends 46 of the legs 44 on either side bend towards each other as the cradle 26 is attached until the tabs 48 are snapped into place retained by retention structures in the form of stops 56 projecting laterally from laterally opposed sides of the cavity 50. The tabs 48 and stops 56 at the ends of the legs 44 form retention structures that retain the cradle 26 to the base 22. The stops 56 are disposed between the bottom surface 52 and the top deck 54. Channels are formed on either side of the cavity 50 laterally between the stops 56 and the bottom surface 52 of the base. The legs 44 are of sufficient length to provide a range of motion for the tabs 48 within the channels that extend downwardly from the stops 56 to the bottom surface 52 of the base 22.
[0012] When the cradle 26 is snapped into place on the base 22, the lower roller 30 and its axle 42 are lowered into the cavity 50. The end of the lower roller axle 42 moves down into a slot 58 on the opposite side of the leg 44, as also shown in FIG. 5. The slot 58 is open at the top to receive the lower roller axle 42. The slot 58 terminates in a slot seat 60 at the distal end 46 of the leg 44. The lower roller axle 42 in the slot 58 holds the legs 44 apart, thereby holding the cradle 26 securely to the base 22. The lower roller axle 42 is vertically movable upward from the slot seat 60 along the slot 58. Like the upper roller axle 34, the lower roller axle 42 defines a lateral axis of rotation parallel to the axis of rotation of the upper roller 28 and parallel to the width direction 40. Also like the upper rollers 28, the lower rollers 30 are in-line rollers that rotate parallel to the module length 68. Alternatively, the lower roller axle slots can be formed in the base rather than in channels in the cradle legs. The legs extend through dedicated openings in the base that are spaced laterally from the lower roller cavity. The retention structure in this embodiment is separated from the roller cavity by an intervening base structure.
[0013] After the lower rollers 30 are installed, the upper rollers 28 are placed on the roller bed 32. The upper roller axles 34 are then inserted through the roller bores 36 and end supports 38 to hold the upper rollers 28 in place on the cradle 24. Unlike the lower rollers 30, which can move or float relative to the cradle 24 along the slots 58, the upper rollers 28 cannot, but are essentially fixed in place in the cradle by the axles 34 held in the end supports 38. The slight freedom of movement of the upper rollers 28 relative to the cradle 24 is due to the slight difference in diameter between the upper roller axles 34 and the bore 36. A bump 61 intermediate the upper roller axles 34 resides in the gaps 62 between the end supports 38 of laterally adjacent upper and lower roller sets 64 to prevent the axles from moving out of place. Other axle retention features, such as knurling or thermal deformation of the axles, may be used instead of the bumps 61.
[0014] As shown in FIGS. 1 and 3, the conveyor belt module 20 has a scalloped portion 66 formed in the bottom surface 52 laterally spaced from the lower roller cavity 50. The conveyor belt module 20 extends in a length direction 68 from a first end 70 to a second end 72. First and second sets of hinge elements 74, 76 are laterally spaced along the first and second ends 70, 72 of the base 22. The hinge elements 74, 76 at each end 70, 72 of the module 20 have laterally aligned rod holes 78 formed therein. Wall segments 80 extend upwardly from the hinge elements 74, 76 to form segment walls along each end 70, 72 that enclose the roller assembly 24 in the length direction 68 relative to the base 22. Raised pads 82 on the top deck 54 provide a braking surface for braking the upper rollers 28 when the cradle 26 is lowered. As shown in FIG. 4, the salient portion of the lower roller 30 extends below the bottom surface 52 of the conveyor belt module 20 .
[0015] FIG. 6 shows the roller assembly 24 in the lowered position, with the upper roller 28 at a lowered height level. In the lowered position of the roller assembly 24, the upper roller 28 rests on the brake pad 82 that extends through the opening 84 in the cradle 26, as also shown in FIG. 5. The weight of a conveyed item, such as a package, parcel, box, tray or bag, resting on the upper roller 28 presses the upper roller in the cradle 26 downward against the brake pad 82. Even if there is no conveyed item on the upper roller 28, its weight alone exerts a slight braking contact on the brake pad 82. The contact of the pad 82 with the upper roller 28 prevents the roller from rotating. The lower roller 30 is in its lowest position, with no contact from below, and the end of its axle 42 rests by gravity on the seat 60 in the slot 58. The cradle 26 rests on the upper deck 54. The item resting on the braked upper roller 28 moves forward with the module 20. As the upper roller 28 wears, its diameter decreases and it begins to lose contact with the brake pads 82 in the lowered position of the roller assembly 24. Such loss of contact indicates that the upper roller 28 needs to be replaced.
[0016] FIG. 7 shows the roller assembly 24 in a raised position at a height level higher than the lowered position, with the lower roller contacting the raised bearing surface 86. The lower roller 30 is forced upwards, with the end of its shaft 42 moving upwards in the slot 58 (FIG. 5). As the lower roller 30 moves upwards along the slot 58 relative to the cradle 20, it pushes against the upper roller 28, which rises upwards with the cradle 20. The brake pads 82 below the raised cradle 26 do not contact the upper roller 28. With the roller assembly 24 in the raised position, the lower roller rotates in a first direction 88, causing the upper roller 28 to rotate in an opposite direction 89, as the module 20 is driven in a direction of travel 90 and the lower roller 30 rolls along the bearing surface 86. Any items resting on the upper roller 28 are pushed in the opposite direction of travel 90 and are removed from the module 20. For effective engagement between the lower roller 30 and the upper roller 28, the outer surfaces of the rollers are made of a high friction material such as rubber or elastomer. Alternatively, the outer circumferential surface of the lower roller and the portion of the upper roller which engages the lower roller may be a gear-like surface to ensure positive engagement without slippage.
[0017] 8 and 9 show a portion of a conveyor belt 92 made up of conveyor belt modules 20 as in FIG. 1. The belt 92 includes a series of rows 94 of belt modules 20 arranged at both ends with a first set of its hinge elements 74 interleaved with a second set of hinge elements 76 of an adjacent row at a hinge joint 96. Aligned holes 78 in the interleaved hinge elements 74, 76 provide lateral passages for hinge rods (not shown) that join the rows 94 to one another and form hinge joints 96 at which the belt 92 can articulate. As shown in FIG. 8, the upper rollers are arranged in lanes 98 spaced apart across the width of the conveyor belt 92. As shown in FIG. 9, the lower rollers 30 are also arranged in lanes 99 spaced apart across the width of the bottom surface 52 of the conveyor belt 92. The scalloped portion 66 of the bottom surface 52 is also arranged in a lane 100 that is laterally offset from the lower roller lane 99.
[0018] FIG. 10 shows a conveyor path and roller actuation arrangement for the conveyor belt 92 of FIG. 8. The conveyor path is characterized by laterally spaced linear wear strips 102 that extend along the conveyor path parallel to the belt travel direction 104. The wear strips support the conveyor belt along its bottom surface in lanes between the lower rollers. Roller actuation assemblies 106 arranged in a two-dimensional matrix each have a pair of upwardly facing bearing surfaces 108, 109 that sandwich one of the wear strips 102. One row of the matrix is shown enlarged in FIG. 11. The matrix arrangement forms a roller actuation lane 103 that extends along the length of the conveyor path. The roller actuation lane 103 coincides with an associated lower roller lane 99 (FIG. 9) of the conveyor belt such that the lower rollers 30 (FIG. 9) can ride on the bearing surfaces 108, 109 when the roller actuation assembly 106 is actuated. Each roller actuation assembly 106 defines an individually controlled roller actuation zone of the conveyor. Successive groups of roller actuation assemblies 106 operating together define a larger roller actuation zone on the conveyor. FIG. 10 also shows that the carryway has smaller diameter nose rollers 110, 111 at both ends for a positive transition to and from the ends of the conveyor belt. The lanes 100 of the scalloped portion 66 of the conveyor belt 92 in FIG. 9 are aligned with the nose rollers 110, 111. Other conveyor configurations are possible. For example, sprockets or nose bars at the ends of the carryway can be used with the conveyor belt 92.
[0019] 12-14 show further details of the roller actuation assemblies 106. Each assembly 106 includes a bearing unit 112 slidably mounted to an actuator base 114. The base 114 is mountable to a conveyor frame (not shown) using fasteners 116. The bearing unit 112 has two bearing blocks 118, 119 extending lengthwise in the direction of belt travel 104 (FIG. 10). The bearing units 112 may be solid, but for lighter weight they may also be largely honeycombed with reinforcing walls surrounding the internal cells or pockets. A guide 107 rising from the actuator base 114 extends into two of the internal pockets of the bearing unit 112 in the lowered position to hold the bearing unit in alignment. Bearing surfaces 108, 109 form the tops of the bearing blocks 118, 119. The bearing units 112 may be made of materials such as nylon or UHMW to enhance wear life. The middle section 120 of the bearing unit 112 is connected to the opposing sides of the bearing blocks 118, 119. The upper surface 122 of the middle section 120 is located below the upper bearing surfaces 108, 109. The wear strip support 124 is fixedly attached to the actuator base 114 by screws 126. Fins 128 extend upwardly from the wear strip support 124. A T-shaped wear strip 102 (FIG. 11) having a split stem is attached to the fin 128 between the two bearing blocks 118, 119. A V-shaped projection 129 extending downwardly from the bottom surface of the wear strip support 124 is received in a corresponding V-shaped recess opening into the upper surface 122 of the middle section 120 when the bearing unit 112 is raised and positioned. Notches 130 in the fins 128 define the ends of the wear strip segments with bumpers (not shown) in one position or the other. Each bearing block has vertical vanes 132, 133 at either end. The vanes 132 at one end are laterally offset from the vanes 133 at the other end so that the vanes of adjacent roller actuation assemblies 106 can be staggered as in FIG.When the bearing units 112 of adjacent roller actuation assemblies 106 are in the raised position, the alternating vanes 132, 133 form overlapping flat bearing surfaces. The overlapping alternating vanes 132, 133 form a flat surface bridge between adjacent raised bearing surfaces. The upper tip corners 134 of the vanes 132, 133 are chamfered to prevent the conveyor belt from catching at the interface between adjacent roller actuation assemblies 106.
[0020] The bearing unit 112 is vertically movable relative to the stationary actuator base 114 and the wear strip support 120 by an actuator 136 attached to the actuator base. The actuator 136 is shown as a pneumatically operated bladder and is coupled to the bottom of the bearing unit 112. When the bladder actuator 136 is inflated through its nipple 138 from a source of compressed air via a valve (not shown), as in FIG. 14, it stretches a spring 140, pushing the bearing unit 112 up to a raised position where the bearing surfaces 108, 109 contact the lower rollers of a conveyor belt supported on the transport path. The spring has an upper seat 141 at the bottom surface of the stationary wear strip support and a lower seat 143 at the blind end of the recess in the middle section 120. When the bladder actuator 136 contracts, a spring 140 biases the bearing unit 112 downwardly to a lowered position where the bearing surfaces 108, 109 are lowered and out of contact with the lower rollers of the conveyor belt when the spring relaxes. Although the actuator 136 has been described as a pneumatically actuated bladder, other actuators such as hydraulic or electromagnetic could be used to raise and lower the bearing unit 112.
[0021] Figures 15 and 16 show the operation of the conveyor belt 92 with the belt rollers 28, 30 deactivated and activated. In Figure 15, the bearing unit 112 is shown in a lowered deactivated position with its upper bearing surface 108 below the level of the lower end of the lower roller 30 and out of contact with the lower roller, with the lower roller axle resting on the slot seat 60 (Figure 5). The weight of the conveyed article 142 resting on the upper roller 28 presses the upper roller downward against the brake pad 82. As the upper roller 28 is prevented from rotating, the article 142 does not move relative to the belt 92 and therefore advances with the belt 92 in the belt travel direction 104.
[0022] When the bearing unit 112 is raised by the actuator to its raised operating position as shown in FIG. 16, the lower roller 30 moves along the upper bearing surface 108 of the bearing unit 112. The level of the upper bearing surface 108 is slightly below the level of the upper surface of the belt support wear strip. Alternatively, if the conveyor belt has a concave channel or scallop at the lower roller position, the upper bearing surface 108 is provided at a higher level than the upper surface of the wear strip. The upward force of the bearing unit 112 pushes the lower roller 30 upward along the slot 58 (FIG. 5) into contact with the upper roller 28. As the conveyor belt 92 advances in the belt travel direction 104, the lower roller 30 rotates as shown, which causes the upper roller 28 to rotate in the opposite direction as shown. Because the tangential velocity of the upper roller is opposite to the belt travel direction 104, the conveyed article 142 moves backwards relative to the conveyor belt 92 at the same velocity, and therefore remains in place on the conveyor. In that way, the article can remain on the conveyor belt 92 for extended periods of time without backline pressure and without a physical barrier blocking the transport path, and the article can be quickly accelerated forward at the appropriate time by deactivating the actuator and allowing the spring and gravity to rapidly lower the bearing unit 112 below the article.
[0023] As shown in FIG. 8, each upper roller 28 has a central portion 144 sandwiched between a pair of outer portions 146. The diameter of the central portion 144 is smaller than the diameter of the outer portions 146. The central portion 144 is the portion of the upper roller 28 that contacts the lower roller when the roller actuation assembly is in the raised operating position. If there is no slippage between the lower roller and the central portion 144 of the upper roller 28, the tangential velocities of the top of the lower roller and the central portion of the upper roller are equal in magnitude to each other and equal to the belt speed, but opposite in direction. The tangential velocity of the larger diameter outer portion 146 of the upper roller 28 is greater than the tangential velocity of the smaller diameter central portion. Since slippage between the lower roller and the upper roller 28 or bearing surface is a common operating condition, the slightly larger diameter of the outer portions 146 and the associated increased tangential velocity of the outer portions compensates for the slippage-induced reduction in roller speed relative to the belt speed. Without slip compensation, conveyed articles may creep forward along the conveying path instead of stagnating or moving slowly and acceptably backward. Forward creep in the working roller working zone is unacceptable because articles may proceed forward from the working zone into the non-working zone and be improperly carried downstream by the conveyor belt. On the other hand, backward creep in the working zone is acceptable because even if the article does move backward, once it reaches the upstream end of the working zone, the non-working rollers prevent the article from creeping further backward through the adjacent upstream non-working zone. If the upper and lower rollers have gear-shaped surfaces for positive engagement, the diameter of the gear-shaped central portion of the upper roller need not be smaller than the diameter of the outer portions.
[0024] 17 and 18 show a conveyor 150 using the conveyor belt 92 of FIG. 8 and the roller actuation assembly 106 of FIG. 10. The conveyor belt 92 is attached to a conveyor frame 152. An upper carryway 154 is formed by the wear strips 102 of FIG. 10. The roller actuation assembly 106 in the carryway 154 is below the belt 92 downstream of a package detection system 156 which detects the profile (length and width) of the articles entering the conveyor 150. The conveyor belt 92 passes over nose rollers 110, 111 at the end of the carryway 154. The conveyor belt 92 is driven by a motor driven sprocket 158 on the lower belt return just after the exit nose roller 111. An idle return roller 160 supports and guides the belt 92 on the return.
[0025] An article detection system 156, which may include a camera, range finder or optical detector, can determine the size and shape of the articles on the belt 92 and reposition groups of articles on the belt as necessary. For example, if side-by-side articles must be separated, the roller actuation assembly 106 under one of the side-by-side articles can be actuated to hold that article while the other article on the braked, deactivated roller can proceed along the conveyor path 154 in the belt travel direction 104. Similarly, gaps can be provided between successive articles.
[0026] FIG. 19 shows a block diagram of a control system that can be used with the conveyors of FIGS. 17 and 18. A processor 160, such as a programmable controller or other programmable processing device, receives information from the article detection system 156 from which the processor determines the size, shape and location of each article. Together with belt speed information, for example from a shaft encoder 162 attached to the drive shaft, the processor 160 executes program instructions stored in a program memory to determine the location of an article on the belt at any time and its relationship to the roller actuation assembly that underlies the article. Once the location of the article is known, the processor 160 executes further instructions to individually selectively activate or deactivate each of the actuators 136 of the roller actuation assemblies in each roller actuation zone, thereby activating or deactivating the belt rollers passing through that zone accordingly. The processor can also adjust the speed of the conveyor belt by controlling its motor drive 164.
[0027] It should be noted that the terms "top", "bottom", "upper", "lower", "upper side" and "lower" refer to the orientation of the conveyor belt and roller actuation assemblies on the horizontal conveying path and are not used in an absolute limiting sense but in a relative sense as an aid to explanation.
Claims
1. A conveyor belt comprising: The bottom surface and a plurality of cradles, each cradle supporting at least one roller set, the roller sets comprising: a lower roller having a protruding portion protruding below the bottom surface; a pair of upper rollers forming a support surface for the conveyed article; the lower roller and the upper roller are rotatable on an axis perpendicular to a direction of belt movement; When the lower roller is in contact with the upper roller, rotation of the lower roller in one direction causes the upper roller to rotate in the opposite direction; each cradle is translatable from a first position, in which the upper rollers are at a first elevation level, to a second position, in which the upper rollers are at a second, higher elevation level and in contact with the lower rollers.
2. 2. The conveyor belt according to claim 1, A conveyor belt, wherein the upper roller is axially longer than the lower roller.
3. 2. The conveyor belt according to claim 1, A conveyor belt, wherein the diameter of the lower roller is greater than the diameter of the upper roller.
4. 2. The conveyor belt according to claim 1, 11. A conveyor belt comprising: a first roller having a first end and a second end; a second roller having a second end and a third end; a third roller having a second end and a fourth end; a fourth roller having a second end and a fourth end;
5. 2. The conveyor belt according to claim 1, 10. A conveyor belt comprising: a shaft defining an axis of rotation about which the upper roller rotates; and the cradle including end supports for holding ends of the shaft.
6. 2. The conveyor belt according to claim 1, A conveyor belt, wherein each of the cradles includes two roller sets axially spaced from one another.
7. 2. The conveyor belt according to claim 1, the cradle having a pair of legs depending from the cradle to a distal end with slots formed in the legs extending to lower portions of the slots above the distal end, and the lower roller having an axis defining an axis of rotation of the lower roller and an end portion thereof received in the slots on either side of the lower roller.
8. 8. The conveyor belt according to claim 7, a conveyor belt including a tab at a distal end of each of the legs, the conveyor belt including a retaining structure that engages the tab to retain the cradle on the conveyor belt.
9. 2. The conveyor belt according to claim 1, 11. A conveyor belt comprising: an upper pair of rollers that move with the cradle; and a lower roller that is movable with or relative to the cradle.
10. 2. The conveyor belt according to claim 1, a braking surface extending into the cradle and contacting the upper roller when the cradle is in the first position, thereby inhibiting rotation of the upper roller.
11. 11. The conveyor belt of claim 10, 1. A conveyor belt comprising a series of rows of one or more belt modules having spaced hinge elements at either end, the rows of belt modules interconnected by hinge rods extending through alternating hinge elements in adjacent rows, the braking surfaces being formed on individual ones of the belt modules, and the cradles being supported on the individual ones of the belt modules.
12. 2. The conveyor belt according to claim 1, A conveyor belt, wherein the bottom surface is scalloped at spaced lanes extending in the direction of belt travel.
13. 1. A conveyor belt module comprising: A base and a roller assembly slidably mounted to the base. the base extends longitudinally from a first end to a second end and laterally in width from a first side to a second side, the base comprising: a bottom and a top deck; a first hinge element spaced apart along the first end and a second hinge element spaced apart along the second end; a cavity opening to the bottom surface and the top deck; a boss on the upper deck; The roller assembly includes: a cradle having at least one pair of side-by-side roller beds and end supports at either end of the roller beds; an upper roller in the roller bed; a lower roller disposed within the cavity and having a protruding portion extending below the bottom surface, the lower roller having a lower roller axis; an upper roller axis supported by the end supports and extending laterally through the upper roller to define a lateral axis of rotation of the upper roller; the cradle further includes an opening in the roller bed for the boss; when the lower roller is raised, it presses against the upper roller, forcing the cradle up and away from the upper deck so that the boss does not extend through the opening into the roller bed, and rotation of the lower roller in one direction causes the upper roller to rotate in the opposite direction; 11. A conveyor belt module comprising: a conveyor belt module including a conveyor unit including a conveyor belt base and a conveyor belt assembly; a conveyor belt module including a conveyor belt base and a conveyor belt assembly;
14. 14. The conveyor belt module of claim 13, the base includes stops projecting from opposite lateral sides of the cavity at locations between the bottom surface and the top deck to define channels extending from the bottom surface to the stops; the cradle includes a pair of legs extending downwardly from the cradle through the cavity toward the bottom surface and sandwiching the lower roller, each leg comprising: a distal end and a slot, the slot extending downwardly from the roller bed to a slot seat proximate the distal end, and an end of the lower roller axle being within the slot on either lateral side of the cavity, thereby providing a lateral axis of rotation for the lower roller; a tab extending laterally away from the lower roller at a distal end of the leg and engageable by the stopper to secure the cradle to the base; The conveyor belt module of claim 1, wherein the legs are sufficiently long so that the tabs have a range of motion along the channel from the stops to the bottom surface.
15. 14. The conveyor belt module of claim 13, a wall segment extending upwardly from the hinge element to form a laterally extending segment wall at first and second ends of the base thereby longitudinally surrounding the upper roller assembly.
16. 14. The conveyor belt module of claim 13, A conveyor belt module, wherein the lower roller has a diameter greater than the diameter of the upper roller.
17. 14. The conveyor belt module of claim 13, 11. A conveyor belt module comprising: a lower roller having an axial length in a width direction that is shorter than an axial length in a width direction of the upper roller;
18. 14. The conveyor belt module of claim 13, 11. A conveyor belt module comprising: a first roller having a first end and a second end; a second end and a third end; a third end and a fourth end; a fourth end and a fourth end;
19. 20. The conveyor belt module of claim 18, 13. A conveyor belt module comprising: a lower roller contacting a central portion of an upper roller.
20. 14. The conveyor belt module of claim 13, 1. A conveyor belt module comprising: two lower rollers, the base having two laterally spaced apart stops, bosses and cavities for the two lower rollers, and the upper roller assembly including two laterally spaced apart cradles.
21. A roller actuation assembly comprising: An actuator base; A bearing unit slidably mounted on the actuator base, a pair of bearing blocks having upper bearing surfaces extending longitudinally in a first direction from a first end to a second end; a bearing unit including an intermediate portion connected to the pair of bearing blocks and having an upper surface below the level of the upper bearing surface; an actuator mounted to said actuator base and coupled to said bearing unit for moving said bearing unit between a lowered position and a raised position.
22. 22. The roller actuation assembly of claim 21, 4. A roller actuation assembly, wherein the actuator is a pneumatic actuator disposed between the actuator base and the bearing unit.
23. 22. The roller actuation assembly of claim 21, a wear strip support fixedly attached to said actuator base above an upper surface of an intermediate portion of said bearing unit.
24. 24. The roller actuation assembly of claim 23, a spring extending from said wear strip support to an upper surface of said intermediate portion of said bearing unit and biasing said bearing unit downwardly toward a lowered position.
25. 22. The roller actuation assembly of claim 21, the bearing block having vanes extending from the first end and the second end in the first direction, the vanes extending from the first end being offset from the vanes extending from the second end such that the vanes can be interleaved with vanes of an adjacent roller actuation assembly.
26. A conveyor comprising: a conveyor belt; a plurality of roller actuation assemblies disposed beneath the conveyor belt; and wear strips; The conveyor belt is The bottom surface and A plurality of roller assemblies arranged in lanes extending in a belt travel direction, each of the roller assemblies comprising: a lower roller having a protruding portion protruding below the bottom surface; a pair of upper rollers forming a support surface for the conveyed article; the lower roller and the upper roller are rotatable on an axis perpendicular to the direction of belt movement; a plurality of roller assemblies, wherein when the lower roller is in contact with the upper roller, rotation of the lower roller in one direction causes the upper roller to rotate in an opposite direction; a cradle supporting the pair of upper rollers; the cradle and the lower roller are vertically movable; each of the plurality of roller actuation assemblies is associated with one or more of the lanes of the roller assembly; and one or more bearing surfaces extending longitudinally in the direction of belt travel beneath the lower roller in one or more of the lanes of the roller assembly; wear strip supports disposed below a bottom surface of the conveyor between the lower rollers of successive lanes; an actuator for moving the one or more bearing surfaces from a lowered position, out of contact with the lower rollers of an associated lane, to a raised position providing a surface against which the lower rollers of the associated lane can rotate in one direction to cause the upper rollers to rotate in the opposite direction as the conveyor belt advances in the direction of belt travel; a wear strip supported on the wear strip supports so as to contact a bottom surface of the conveyor belt between lower rollers of successive lanes;
27. 27. A conveyor as claimed in claim 26, A conveyor comprising: a plurality of roller actuation assemblies that are independently actuated and arranged in a two-dimensional matrix of columns corresponding to lanes and rows extending across the width of the conveyor.
28. 27. A conveyor as claimed in claim 26, 1. A conveyor comprising: an item detection system; and a processor that executes program instructions to receive item size and location information from the item detection system, determine the location of the item on the conveyor belt and its relationship to the roller actuating assembly below the item, and selectively activate or deactivate the roller actuating assembly.
29. 27. A conveyor as claimed in claim 26, 11. A conveyor comprising: a roller actuation assembly including: a first roller assembly having a first lane and a second roller assembly having a second lane;
30. 27. A conveyor as claimed in claim 26, 11. A conveyor comprising: a roller actuation assembly having vanes extending longitudinally in the direction of belt travel from opposite ends of the bearing surface, the vanes extending from one end being offset from the vanes extending from the second end such that the vanes of adjacent roller actuation assemblies may be interleaved.
31. A conveyor belt comprising: The bottom surface and A plurality of cavities opening to the bottom surface; a lower roller attached to each of the cavities, the lower roller having a protruding portion protruding below the bottom surface and movable along the cavity; a plurality of cradles, each cradle supporting two or more roller sets, each of the two or more roller sets comprising: a pair of upper rollers forming a support surface for the conveyed article; the lower roller and the upper roller are rotatable on axes extending laterally perpendicular to the direction of belt movement; the two or more roller sets being laterally spaced across a width of the conveyor belt; each of the roller sets is associated with one of the lower rollers; when the lower roller is in contact with an upper roller of an associated roller set, rotation of the lower roller in one direction causes the upper roller to rotate in the opposite direction; 11. A conveyor belt comprising: a cradle, the cradles each being translatable from a first position in which the upper rollers are at a first elevation level to a second position in which the upper rollers are at a higher second elevation level and in contact with the lower rollers.
32. 32. The conveyor belt of claim 31, 11. A conveyor belt comprising: a lower roller including a shaft mounted for rotation, an end of the shaft supported within the cradle for relative movement therewithin.
33. A conveyor belt comprising: The bottom surface and A plurality of cavities opening to the bottom surface; a plurality of cradles, each cradle supporting one or more roller sets, each of the one or more roller sets comprising: a pair of upper rollers forming a support surface for the conveyed article; a lower roller having a protruding portion protruding below the bottom surface from one of the cavities and movable along the cavity; a lower roller axle on which the lower roller is rotatably mounted, the lower roller axle having an end that is received in the cradle and is movable relative to the cradle; the lower roller and the one or more upper rollers are rotatable on axes extending laterally perpendicular to the direction of belt movement; when the lower roller is in contact with the upper roller, rotation of the lower roller in one direction causes the upper roller to rotate in the opposite direction; 11. A conveyor belt comprising: a cradle, the cradles each being translatable from a first position in which the upper rollers are at a first elevation level to a second position in which the upper rollers are at a higher second elevation level and in contact with the lower rollers.
34. 34. The conveyor belt of claim 33, a cradle having a pair of legs extending into the cavity and defining opposed vertical slots for receiving ends of the lower roller axles.