Automatic stacking spiral belt conveyor with smooth diameter reduction

Abstract

A spiral conveyor having an automatic stacking conveyor belt that is positively driven on a spiral path up or down a drive drum. Stacker supports on both sides of the belt support the top layer. A locking structure on the outer stacker supports interlocks successive layers. The drive member of the drive drum has a belt entry segment and a positive drive segment. The positive drive segment has ridges that engage the inside of the belt without slipping. The entry segment provides a smooth drum diameter reduction without drive ridges for multiple belt layers entering the spiral path.

Description

[Technical field]

[0001] FIELD OF THEINVENTION This invention relates generally to power driven conveyors, and more particularly to spiral belt conveyors. [Background technology]

[0002] Conveyor belts are commonly used to transport bulk materials, such as food or other materials, that need to be transported in a cooled or refrigerated environment. Typical conveyor belts have the advantage that they require relatively little energy to transport the bulk materials across a horizontal surface. However, the transport of bulk materials is limited by such systems to horizontal paths or paths with only a relatively small incline. To overcome greater heights or inclines, it is necessary to transfer the bulk materials to another conveyor system, for example a bucket chain conveyor. When transporting materials to be refrigerated, it is often desirable to maximize the transport time in the cooled environment. It is desirable to provide a conveyor belt system that transports items along extended paths.

[0003] Spiral belt conveyors, in which the conveyor belt follows a helical path, are used in certain applications to achieve extended paths with a minimum of floor space. For example, spiral belt conveyors are often used in freezers and drying ovens to achieve long transport paths with a small footprint.

[0004] Self-stacking spiral belts are used to create a helical path with minimal framework. Self-stacking conveyor belts use side plates or side guards coupled to the side edges of the conveyor belt to create a self-supporting stack. The belt travels a straight path until it enters a spiral or helical structure at a tangential infeed point. When aligned in the helical structure, the bottom layer of the belt is supported by a frame or drive system and the upper layers are supported by the lower layers. The interface between adjacent layers is designed to keep the belt supported and laterally aligned. The layers are laterally aligned by placing the top edge of the lower side guard against the bottom side edge of the belt of the upper layer.

[0005] To reduce the tension in the belt, some self-stacking spiral belts are driven without slipping by a vertical drive bar located around the circumference of the drive drum, the diameter of which is greatest at the tangential feed point. The lower end of the drive bar is slightly recessed above the level of the tangential feed point. However, until the belt reaches the level of the drive bar, it is pulled only by the pulling force of the belt and the frictional contact between the inner edge of the belt and the drive drum. To keep the tension in the belt as low as possible, it is necessary to make the distance between the tangential feed point and the level of the lower end of the drive bar small. Summary of the Invention

[0006] One version of a spiral conveyor embodying features of the invention includes an array of drive members extending a length from a top end to a bottom end, the drive members defining a cylinder having a vertical axis about which the array of drive members can rotate, and a conveyor belt arranged to follow a spiral path in multiple layers above and below the drive members. The conveyor belt extends in thickness from a top surface to a bottom surface and in width from an inner side toward the drive members to an outer side, and includes inner side supports upstanding from the top surface at the inner sides and outer side supports upstanding from the top surface at the outer sides for supporting a bottom surface of the conveyor belt at the inner and outer sides of the upper layer on the spiral path. The outer side supports have first locking structures, and the conveyor belt has second locking structures on the outer side of the bottom surface that engage with the first locking structures of the layer below to lock the layers together. The drive member has an outer surface along which the conveyor belt travels in a helical path, the outer surface being at a greater distance from the vertical axis at a lower end of the drive member than at an upper end for a conveyor belt traveling up a helical path and at a greater distance from the vertical axis at an upper end of the drive member than at the lower end for a conveyor belt traveling down a helical path, and the drive member includes a ridge extending radially outward from the outer surface along a portion of the length of the drive member to reliably drive the conveyor belt along the helical path without slipping.

[0007] Another version of the spiral conveyor includes a conveyor belt having a width extending from a first side to a second side, the conveyor belt including a first side support upstanding from the first side and a second side support upstanding from the second side and including a locking structure. Each of the drive members includes a first segment and a second segment, extends a length in a generally vertical direction, and is rotatable about a vertical axis. At least some of the drive members are configured to positively engage the conveyor belt only at the first segment and drive the conveyor belt without slipping in a spiral path in a plurality of layers locked together by the locking structure. The drive members are configured to move the conveyor belt away from the vertical axis such that the distance of the conveyor belt from the vertical axis varies along the length of the drive members.

[0008] Yet another version of the spiral conveyor includes a spiral stacker belt having a plurality of first and second supports on first and second sides of the stacker belt, the spiral stacker belt being movable up or down a spiral path of a plurality of spaced apart layers and supported by the first and second supports of the lower layer. Drive members extending in a generally vertical direction in length are rotatable about a vertical axis. At least some of the drive members each include a positive drive segment having a drive ridge and an entrance segment without a drive ridge. The entrance segment is below the positive drive segment in an ascending spiral stacker belt and above the positive drive segment in a descending spiral stacker belt. The spiral stacker belt enters the spiral path around the plurality of drive members along the entrance segment and is driven positively without slipping up or down the spiral path by the drive ridges of the positive drive segment. The layers of the spiral stacker belt wrap around the entrance segment before engaging the positive drive segment.

[0009] In another aspect, a conveyor belt module embodying features of the invention includes a central section extending longitudinally from a first end to a second end, extending laterally from a first side to a second side, and having a thickness from a top surface to a bottom surface. A side support upstands from the top surface at the second side. A distal end of the side support has a lateral locking structure on either the inner or outer side. The lateral locking structure on the bottom surface of the second side engages with a locking structure on a side support of another such conveyor module below. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an isometric view of an automatic stacking spiral conveyor embodying features of the present invention. [Diagram 2] FIG. 2 is an isometric view of a belt module used to construct an autostacking belt of a spiral conveyor such as that of FIG. 1. [Diagram 3]FIG. 3 is an enlarged axonometric view of an outer side support with a locking structure for the belt module of FIG. 2; [Figure 4] FIG. 3 is an enlarged isometric view of an outer side of the belt module of FIG. 2 with the side support removed. [Diagram 5] FIG. 4 is an enlarged bottom isometric view of an outer side of the belt module of FIG. 2 with the side support of FIG. 3 attached. [Figure 6] FIG. 4 is an axonometric view of two outer side supports as in FIG. 3 locked together. [Figure 7] FIG. 3 is an isometric view of a portion of two layers of an autostacking belt made of belt modules as in FIG. 2 interlocked on the outer sides of the belt. [Figure 8] FIG. 2 is an axonometric view of a portion of a spiral drive drum usable in the autostacking spiral conveyor of FIG. 1; [Figure 9] FIG. 9 is an enlarged vertical elevational view of the inlet portion of the drive drum of FIG. 8. [Figure 10] FIG. 9 is a vertical elevation view of the inlet portion of the drive drum of FIG. 8 showing engagement of the lower layer of the conveyor belt with the drive drum. [Figure 11] FIG. 3 is an axonometric view of another version of a locking outer side support for a belt module as in FIG. 2 . [Figure 12] FIG. 12 is an axonometric view of an outer side support as in FIG. 11 shown interlocked from layer to layer. [Figure 13] 13A-13C are enlarged views of the outer side support of FIG. 12 immediately before and after interlocking engagement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A self-stacking spiral conveyor system is shown diagrammatically in FIG. 1. The spiral belt conveyor 10 conveys articles vertically along a substantially helical path. The spiral belt conveyor includes conveyor belts 12 - spiral self-stacking, i.e. stacker, belts - arranged in a helical stack 11, including layers 13 of belts stacked consecutively and directly on top of each other. The belts move around various take-up, idle and feed sprockets 22 as they travel from an exit at the top of the stack back to an entrance at the bottom. Alternatively, the belts may enter at the top of the stack and exit at the bottom. The spiral belt conveyor 10 can be used in refrigerators or coolers, for example, where articles are conveyed in an extended path for cooling, or in heating systems to bake, temper or heat products.

[0012] The conveyor belt 12 is comprised of a series of rows, each row including one or more belt modules 14, such as the belt module of FIG. 2. A row may include a single module spanning the width of the belt, or multiple side-by-side modules. The exemplary belt module 14 includes a central portion 16 that extends longitudinally in the belt travel direction 15 from a first end 18 to a second end 19, laterally from an inner side 20 to an outer side 21, and in thickness from a top side 22 to a bottom side 23. A first set 24 of hinge elements is formed along the first end 18 and a second set 26 is formed along the second end 19 of the module. Rod openings 28, 29 of the hinge elements are aligned to form a lateral passageway through the first and second sets of hinge elements. The passageway allows for the entry of hinge rods (not shown) that connect rows of similar side-by-side modules to adjacent rows of modules to form the conveyor belt. A first set of hinge elements 24 along a row of modules are interleaved with a second set of hinge elements 26 in a longitudinally adjacent row to form a hinge together with the hinge rod. The rod openings 28, 29 through one or both of the leading and trailing hinge elements may be elongated in the direction of belt travel to allow the belt to collapse on the inside of a turn while the outer edges are splayed.

[0013] The belt module 14 is preferably injection molded from a thermoplastic material such as polyethylene, polypropylene, acetal, nylon or composite resins. The belt module may have any suitable construction and is not limited to this exemplary embodiment.

[0014] The side supports 30, 32 are coupled to each side edge of the conveyor belt row. In the embodiment of FIG. 2, a single module 14 spans the entire row, with side supports 30, 32 upstanding from each side of the module. Alternatively, the conveyor belt row may include multiple modules arranged side-by-side, with the inner side support 32 coupled to the inner side 20 of the inner module and the outer side support 30 coupled to the outer side 21 of the outer module. The side supports may be integrally formed with the modules or may be coupled to the modules using screws, bolts, ultrasonic welding, snap fits or other suitable fastening means. The side supports encourage the belt to stack in a spiral configuration, as each module rests on the side supports of the lower layer.

[0015] As shown in FIG. 3, the outer side support 30 has a locking structure 34 on its top edge and a complementary locking structure 36 on its bottom edge. The outer support 30 has a base 35 from which two legs 38, 39 extend upwardly to a bridge 40 at the top. The complementary locking structure 36 is formed at the bottom of the base 35 along with a guide 42. As shown in FIGS. 4 and 5, the outer side support 30 snaps into place in an opening 44 in the outer side 21 of the belt module 14. The complementary locking structure 36 of the outer support 30 extends downwardly from the module to engage with the top locking structure of the layer below. The locking structure shown in this example is in the form of rounded teeth, but can be realized in different interlocking shapes, such as sawtooth, triangular, or other suitable interlocking shapes.

[0016] The outer side support 30 shown in Figure 3 has a base 35, two legs 38, 39, and a large opening 46 surrounded by a bridge 40. However, for strength, the outer side support 30 may include diagonal struts 48 such as those in Figure 2, or the outer side support may be a plate lacking an opening. If the outer side support 30 is integral with the module 14, the lower locking structure 36 and guide 42 may instead be formed in the bottom surface 23 of the module.

[0017] Figure 6 shows the engagement of the top locking structure 34 on the outer support 30 of the lower layer with the complementary locking structure 36 on the upper layer. When the two layers are interlocked, there is no relative slippage in the belt travel direction 15, as shown in Figure 7. Additionally, the upper locking structure 34 is restrained against lateral wander by laterally spaced depending guides 50, 52 that extend longitudinally on the bottom side of the belt. Guide 52 and guide 42 on the bottom of the outer side support 30 together form a bilateral guide, as shown in Figure 5.

[0018] 8-10 show a drive drum 54 of an automatic stacking spiral conveyor. The drum 54 has an arrangement of parallel drive members 56 that extend generally vertically in length from an upper end 58 to a lower end 59 and define a cylinder. The drum 54 is rotated in a conventional manner by a drum drive including a motor and gear train (not shown). The drum 54 and the surrounding drive members 56 rotate about a vertical axis 60 (also shown in FIG. 1), which is also the axis of symmetry of the cylinder of varying diameter. The drive members 56 have an outer surface 62 that contacts the inner side 20 of the belt at the tips of driven projections, such as drive lugs 64 (FIG. 2), that project radially inward from the inner side toward the vertical axis to set the distance between the vertical axis and the stacker belt 12.

[0019] The drive member 56 is divided into an entrance segment 74 and a positive drive segment 66 having a ridge 68 extending radially outward of the outer surface 62. The ridge 68 has a drive surface 70 that engages a driven protrusion on the inner side of the stacker belt 12 and drives it on a helical path without slipping. In the example of Figures 8-10, the ridge 68 is formed on the positive drive segment 72 of the drive member 56 whose outer surface 62 is a fixed distance from the vertical axis 60. The belt entrance segment 74 is devoid of ridges and provides a flat outer surface 62 that contacts the inner side 20 of the stacker belt 12. The belt 12 first contacts the drive drum 54 at a tangential infeed point 76 of the entrance segment 74. As the belt 12 tangentially enters the entrance section and follows its helical path, the bottom layer 78 engages the bottom of the second layer 80. The inner and outer supports 30, 32 of the bottom layer move into supporting contact with the bottom surface of the upper layer, and the upper locking structure of the outer support 32 of the bottom layer interlocks with the lower locking structure of the upper layer. Because of the interlock, the upper layer helps drive the lower layer at the entrance segment 74 even though the lower layer is not positively driven by the ridges 68 of the positive drive segment 72. This allows multiple belt layers to gradually advance along the helical path and make contact with the entrance portion before positively engaging the ridges 68.

[0020] To reduce belt tension, the entrance segment 74 has a transition portion, or segment 82, where the distance of the outer surface 62 from the vertical axis 60 varies from a maximum distance at a lower distal end 86 to a smaller minimum distance at a proximal end 87 relative to the positive drive segment 72. The entrance segment 74 may also include a lower entrance portion 88 where its outer surface 62 is a constant distance from the vertical axis 60, i.e., the maximum distance of the transition portion 82. The gradually decreasing effective diameter of the cylindrical drum, i.e., the distance from the vertical axis 60 at the entrance segment 74 to the inner side 20 of the stacker belt 12, allows for reduced belt tension as it enters the positive drive segment 72 and initially engages the drive ridge 68. Even if the entrance segment 74 contacts multiple layers, it is still shorter than the positive drive segment 72, which engages more layers around the drum.

[0021] Another version of a locking outer side support that can be used in a belt module such as that of FIG. 2 is shown in FIG. 11. The support 90 differs from the support 30 of FIG. 3 in that its locking structure does not face upwards. Rather, as shown in FIG. 12, its locking structure 92 faces sideways on an upper bridge 94 at the end of two legs 96, 97 that extend upwards from a base 98. The locking structure 92 faces inwardly of the support 90 for even (or odd) belt rows, and faces outwardly of the support 90' for odd (or even) belt rows. Extending downwards from the base 98 are two dependent guides 100, 101. The guides 100, 101 have laterally oriented locking structures 102, 103, shown in this example as rows of triangular teeth that match the triangular teeth on the upper locking structure 92 on the bridge. As with the outer side support 30 of FIG. 3, the side support can be a replaceable piece or can be formed integrally with the module body. Alternatively, the base may be formed integrally with the module body, with the legs and bridge secured to the module body. Base 98 also defines a plow 104 that projects downwardly into the gap 106 between the opposing locking structures 102, 103. Plow 104 is shown as an elongated triangular wedge with angled faces that extend the length of base 98.

[0022] FIG. 13A shows two adjacent outer supports 90, 90' just prior to locking engagement with laterally facing locking structures 102, 103 of the top belt layer. Chamfered surfaces 108, 109 on the guides 100, 101 direct the bridges 94 of the side supports 90, 90' into the gap 106. When the bridges 94 reach the apex of the plow 104, the bridges of the side supports 90' with their outwardly facing locking structures are pushed outward by the outer angled surface of the plow 104 to engage the complementary locking structures 103 on the inwardly facing surface of the top layer, as shown in FIG. 13B. And the bridges of the side supports 90 with their inwardly facing locking structures are pushed inward by the inner angled surface of the plow 104 to engage the complementary locking structures 102 on the outwardly facing surface of the top layer. In that way, the plow 104 cuts into two successive side supports 90, 90' and brings them into interlocking engagement with the layer above. The lateral interlocking engagement of the layers allows the outer side supports 90, 90' to move with less vertical displacement than the side supports of FIG.

[0023] Although the features of the invention described in detail are directed to an ascending spiral stacker belt, the same features can be used with a descending spiral. In the case of a descending spiral, the entrance segment is inverted and rests on the drive drum above the inverted positive drive segment from which the stacker belt exits at its lower end. It would also be possible for the ridges to extend into the entrance portion of the ascending or descending spiral conveyor.

Claims

1. an array of drive members extending a length from an upper end to a lower end, the array of drive members defining a cylinder having a vertical axis about which the array of drive members is rotatable; a conveyor belt arranged to follow a spiral path in multiple layers above or below the drive member, the conveyor belt has a thickness from the top surface to the bottom surface and a width from the inner side toward the drive member to the outer side, and includes inner side supports upstanding from the top surface at the inner side and outer side supports upstanding from the top surface at the outer side for supporting the bottom surface of the conveyor belt at the inner side and the outer side of an upper layer on the spiral path; the outer side support has a first locking structure and the conveyor belt has a second locking structure on the outer side of the bottom surface that engages with the first locking structure of a layer below to lock the layers together; the drive member has an outer surface along which the conveyor belt runs on the helical path, the outer surface being at a greater distance from the vertical axis than a second segment at a lower end of the drive member for a conveyor belt running upward on the helical path than a first segment extending from the second segment to an upper end thereof, and at a greater distance from the vertical axis than a second segment at a upper end of the drive member for a conveyor belt running downward on the helical path than a first segment extending from the second segment to a lower end thereof; a distance from the vertical axis to an outer surface of the first segment is a constant first distance; the drive member including a ridge only on the first segment, the ridge extending radially outward from an outer surface of the first segment along a portion of the length of the drive member, such that the drive member reliably drives the conveyor belt of the first segment along the helical path without slippage. Spiral conveyor.

2. A spiral conveyor as described in claim 1, wherein the distance from the outer surface of the second segment to the vertical axis varies from the first distance to a larger second distance.

3. 3. The spiral conveyor of claim 2, wherein said drive member includes a third segment having said outer surface at a constant distance from said vertical axis at said second distance, said second segment extending from said first segment to said third segment.

4. 2. The spiral conveyor of claim 1, wherein the second locking structure is formed in the outer side support at the bottom surface of the conveyor belt.

5. 2. The spiral conveyor of claim 1, wherein the first locking structures on the outer side supports alternately face inward and outward along the length of the conveyor belt.

6. 6. The spiral conveyor of claim 5, wherein the second locking structure includes two laterally oriented rows of teeth spaced apart and a wedge projecting into the gap between the two laterally oriented rows of teeth to urge the first locking structure of a layer below laterally into interlocking engagement with the second locking structure.

7. a conveyor belt extending in width from a first side to a second side, the conveyor belt including a first side support upstanding from the first side and a second side support upstanding from the second side and including a locking structure; a plurality of drive members each including a first segment and a second segment, the drive members extending generally vertically in length and rotatable about a vertical axis; at least some of the plurality of drive members are configured to positively engage the conveyor belt only at the first segment and drive the conveyor belt in a spiral path without slipping in a plurality of layers locked together by the locking structure; the plurality of drive members are configured to move the conveyor belt away from the vertical axis such that the distance of the conveyor belt from the vertical axis varies along a length of the drive members. Spiral conveyor.

8. 8. The spiral conveyor of claim 7, wherein the first and second segments have outer surfaces that space the conveyor belt from the vertical axis, the first segment having ridges extending radially outward from the vertical axis to engage the conveyor belt, and the second segment having no ridges to engage the conveyor belt.

9. 8. The spiral conveyor of claim 7, wherein the second segment includes a first portion having an outer surface that is constant a first distance from the vertical axis and a second portion having an outer surface that varies in distance from the vertical axis from the first distance to a second, smaller distance.

10. a spiral stacker belt having a plurality of first and second supports on a first side and a second side of the stacker belt, the belt being movable up or down a spiral path of a plurality of spaced apart layers of the stacker belt, the belt being supported by the first and second supports of the layer below; a plurality of drive members extending generally vertically and rotatable about vertical axes, at least some of which each include: a positive drive segment having a drive ridge; and an entrance segment without drive ridges, the entrance segment being below said positive drive segment in an ascending spiral stacker belt and above said positive drive segment in a descending spiral stacker belt; and a plurality of drive members including the spiral stacker belt enters a spiral path around the plurality of drive members along the entrance segment and is positively driven without slipping up or down the spiral path by the drive ridges of the positive drive segment; a plurality of layers of the spiral stacker belt wrap around the entrance segment before engaging the positive drive segment; Spiral conveyor.

11. 11. The spiral conveyor of claim 10, wherein the positive drive segment has a length greater than a length of the entrance segment.

12. 12. The spiral conveyor of claim 11, wherein the positive drive segments have outer surfaces that have a constant distance from the vertical axis along the drive member.

13. 12. The spiral conveyor of claim 11, wherein the entrance segment includes first and second portions and an outer surface having a constant first distance from the vertical axis in the first portion of the entrance segment and a distance from the vertical axis that varies from the first distance to a smaller second distance in the second portion.

14. 14. The spiral conveyor of claim 13, wherein the second portion of the entrance segment is adjacent to the positive drive segment.

15. 11. The spiral conveyor belt of claim 10, wherein the spiral stacker belt includes a driven protrusion on the first side engaged by the drive ridge of the positive drive segment of the drive member.

16. 11. The spiral conveyor of claim 10, wherein the second support on the second side includes a locking structure for locking the layer of the spiral stacker belt to the layer above on the spiral path.

17. 1. A conveyor belt module comprising: a central portion extending longitudinally from a first end to a second end, laterally from a first side to a second side, and extending thicknesswise from a top surface to a bottom surface; a side support upstanding from the upper surface on the second side, the side support having a distal end with a transverse locking structure in the form of a row of inwardly or outwardly directed teeth; a transverse locking structure in the form of a row of teeth on the bottom surface of the second side for engaging with the locking structure of the side support of another such conveyor belt module below; and 2. A conveyor belt module comprising:

18. 18. The conveyor belt module of claim 17, wherein the side support includes two legs extending upwardly from the second side of the conveyor belt module to a bridge spanning distal ends of the legs, the locking structure being formed on a lateral surface of the bridge.

19. 20. The conveyor belt module of claim 18, wherein the side support includes a base removably attached to the second side and from which the two legs extend upwardly.

20. 20. The conveyor belt module of claim 19, wherein the bottom lateral locking structure is formed in the base of the side support.

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