WO2012102858A1

WO2012102858A1 - Vibration-damped conveyor belt and module and method of manufacture

Info

Publication number: WO2012102858A1
Application number: PCT/US2012/020870
Authority: WO
Inventors: Andrew A. Corley
Original assignee: Laitram, L.L.C.
Priority date: 2011-01-27
Filing date: 2012-01-11
Publication date: 2012-08-02

Abstract

A modular conveyor belt having vibration dampers between adjacent belt rows and a method for making modules of such a belt. A layer of shock-absorbing material protrudes from a face of one belt row to form a point of first damped contact with an adjacent belt row. The energy of the impact between rows is absorbed by the shock-absorbing material to lessen belt vibration and chatter. The layer may be co-injected molded or overmolded onto the molded belt modules or otherwise bonded to the belt module.

Description

VIBRATION-DAMPED CONVEYOR BELT AND MODULE AND METHOD

OF MANUFACTURE

BACKGROUND

The invention relates generally to power-driven conveyors and more particularly to modular side-flexing conveyor belts having vibration dampers between consecutive rows of belt modules.

Side-flexing, or radius, conveyor belts are used to convey articles on a conveying path that includes turns. Modular plastic radius conveyor belts, such as the INTRALOX^® Series 2600 SPIRALOX^® 1.1 Radius belt manufactured and sold by Intralox, L.L.C. of Harahan, Louisiana, U.S.A., are constructed of a series of rows of belt modules linked together end to end at hinge joints. When negotiating a turn, these radius belts collapse at the inside of the turn because the travel path at the edge of belt at the inside of the turn is shorter than the path of the opposite edge at the outside of the turn. Because all the belt tension passes through the outside edge portion of the belt, the outside edge is fully expanded and stretched tight, while the collapsed inside edge is free of tension. Unlike the taut outside edges of the belt rows, the untensioned inside edges are free to move relative to each other in the direction of belt travel. As the inside edges of the rows rub along the inside rail or the side of a drive tower in a spiral conveyor, they tend to stick and release continuously. As they do so, they bump into each other as the belt advances. The bumping causes the belt edges to chatter and the belt to vibrate, which can cause conveyed articles to change their orientations atop the belt. In many applications, product orientation is important. And chatter is annoying.

Thus, there is a need for a conveyor belt that does not vibrate enough to change product orientation. And there is a need to reduce chatter in radius and spiral belts. SUMMARY

These needs and others are addressed by a modular conveyor belt embodying features of the invention. One version of such a conveyor belt comprises a series of rows of one or more belt modules hingedly linked together at hinge joints. Vibration dampers disposed between consecutive rows absorb the impact between consecutive rows as they collapse together during belt travel. In another aspect of the invention, a conveyor belt module comprises a first hinge end and an opposite second hinge end that define first and second hinge axes transverse to a travel direction. First projections spaced apart along the first hinge end are offset

transversely from second projections spaced apart along the second hinge ends. At least one of the first and second projections has a leading face extending transverse to the travel direction and an opposite trailing face. A vibration damper protrudes from at least one of the leading and trailing faces in the travel direction.

In yet another aspect, a method for making a conveyor belt module comprises: (a) forming a conveyor belt module body having leading and trailing faces extending transverse to a travel direction of a conveyor belt made of such conveyor belt modules; and (b) forming a rubber or rubber-like layer on at least one of the leading and trailing spaces.

BRIEF DESCRIPTION OF THE DRAWINGS

These aspects and features of the invention, as well as its advantages, are described in more detail in the following description, appended claims, and accompanying drawings, in which:

FIG. 1 is a plan view of a portion of one version of a modular radius conveyor belt embodying features of the invention;

FIG. 2 is an isometric view of an edge module of the conveyor belt of FIG. 1; and FIG. 3 is a plan view of a portion of another version of a modular radius conveyor belt embodying features of the invention.

DETAILED DESCRIPTION

A portion of a modular plastic conveyor belt embodying features of the invention is shown in FIG. 1. The conveyor belt 10 shown is a radius, or side-flexing, belt following a conveying path that includes straight 12 and curved 13 segments. The belt is constructed of a series of rows 14 of belt modules. Each row extends laterally across the width of the belt from a first side edge 16 to a second side edge 17 and, in the direction of belt travel 18, from a leading end 20 to an opposite trailing end 21 when the belt is traveling to the left in FIG. 1. (The descriptors "leading" and "trailing" are not meant to limit the belt to a certain direction of travel, but merely to help describe the general spatial relationships of various elements of the example versions described.) Each belt row 14 is made up of a number of belt modules arranged side by side. In this example, a row includes a first side edge module 24 and a second side edge module 25 separated at a seam 26. Internal modules (not shown and without belt edge structure) could be positioned between the two side edge modules in a row to form a wider belt. And, even though each row in FIG. 1 includes more than one belt module, each row could be formed of a single module that has side-edge structure 28, 29 at both edges. Consecutive side edge modules are cut to different widths to construct the belt in a bricklay pattern. The belt modules are, for example, injection-molded out of a thermoplastic polymer, such as polyethylene, polypropylene, acetal, nylon, or a composite resin.

Each row 14 of the conveyor belt 10 has a set of leading projections 30', 30" spaced apart laterally along the leading end 20 and a set of trailing projections 31', 31" spaced apart laterally along the trailing end 21. The leading and trailing projections are laterally offset from each other so that they can be interleaved with each other. In this example, some of the projections 30', 31' are A-shaped with two legs 32, and other projections 30", 31" have a single leg 33. The projections of each row have elongated rod holes 34, 35 (FIG. 2) that form a lateral passageway with the aligned holes of the interleaved projections of adjacent modules. A hinge rod 36 is received in the passageway to connect adjacent belt rows together at a hinge joint 38.

In a turn 13, as in FIG. 1, the inside edge 16 of the radius conveyor belt 10 travels a shorter distance than the edge 17 at the outside of the turn. The elongated rod holes 34, 35 allow the inside edges 16 of the rows to collapse at the inside of a turn as the outside edges 17 are expanded and bear all the belt tension. Because the inside edges 16 of the rows 14 bear no tension in a turn, they have a certain freedom of movement relative to each other. As the inside edges come into frictional contact with an inside rail 40 or structure on the periphery of a drive drum in a spiral conveyor, the edges can stick against the rail until the belt advances far enough to produce enough force through the belt row to overcome the friction preventing movement of the edge along the rail. Because no belt tension is borne by the inside edge 16, it can jump forward enough to bump into a leading belt row. A vibration damper 42 is formed as a shock-absorbing layer on a trailing face 44 of a projection 30' at the inside edge 16 of each belt row, as shown in FIGS. 1 and 2. (Although the drawing shows the layer formed on the projection closest to the inside of the turn, it could be formed

alternatively on one or more projections spaced a few projections farther across the row from the inside of the turn. Thus, the term "edge" is not meant to be limited strictly to an outside border, but to a region along a belt row extending inward along the row from the outside border; and the phrase "at the edge" means "in the edge region.") The damper forms a point of first damped contact between adjacent belt rows. The layer is made of a rubber or rubber-like material, such as an elastomer or other viscoelastic material, that has shock-absorbing properties. Examples include materials such as low durometer, soft rubbers, foam rubbers, ethylene propylene diene Monomer (M-class) (EPDM) rubbers, and Santoprene. The layer is co-injection molded or overmolded onto, or otherwise bonded to, the trailing face. A vibration-damping layer 42' could alternatively be formed on an opposite leading face 45, as shown by the phantom lines in FIG. 2. In either position, the layer acts as a vibration damper or shock absorber between consecutive belt rows. As the inside edge 16 of the belt collapses at the inside of a turn 13, the vibration damper contacts the adjacent row before structure at other positions to cushion the impact of the collapsing inside edges and reduce belt vibration, which can cause conveyed articles to move out of their preferred orientation or position on the belt. A shock-absorbing layer 46 could also be formed on the trailing face 48 (or leading face 49) at the other side edge 17 of the belt in case the belt has to negotiate turns in the opposite direction.

A conveyor belt having a vibration damper formed differently is shown in FIG. 3. In this version, the conveyor belt 50 has standard rows 52 of modules and damper rows 53. The damper rows have vibration dampers 54 retained in cavities 56 in side edges 58 of the belt. The dampers, which are made of a shock-absorbing material, protrude from leading and trailing faces 60, 61 of the edge portion of the damper rows towards the confronting trailing and leading faces 63, 62 of standard rows 52. The vibration dampers 54 are pressed-fitted or bonded in the cavities.

Although the invention has been described with reference to a couple of versions, other versions are possible. For example, in all the versions described, the vibration dampers have a flat face. But the face could include ridges, dimples, bumps, or other textures to reduce vibration or chatter. As another example, vibration dampers could be formed at different positions on each belt row rather than at just one position. And the vibration dampers could be manufactured as separate pieces with structure that allows them to be attached to the conveyor belt, such as by snapping in place. So, as these few examples suggest, the scope of the claims is not meant to be limited to the details of the exemplary versions. What is claimed is

Claims

1 A modular conveyor belt comprising:

a series of rows of one or more belt modules hingedly linked together at hinge joints; a plurality of vibration dampers disposed between consecutive rows to absorb the

impact between consecutive rows as the rows collapse together at the vibration dampers during belt travel.

A modular conveyor belt as in claim 1 wherein the vibration dampers are made of a rubber or rubber-like material.

A modular conveyor belt as in claim 1 wherein the vibration dampers are bonded to the rows of belt modules.

4. A modular conveyor belt as in claim 1 wherein the vibration dampers are molded to the rows of belt modules.

5. A modular conveyor belt as in claim 1 wherein the vibration dampers are retained in the rows of belt modules.

6. A modular conveyor belt as in claim 1 wherein the vibration dampers are disposed in the rows in a position to contact an adjacent row before adjacent rows contact each other at other positions when the rows collapse together.

7. A modular conveyor belt as in claim 1 wherein the modular conveyor belt extends in width from a first side edge and a second side edge and wherein the vibration dampers are disposed at at least one of the first and second side edges.

8. A modular conveyor belt as in claim 1 wherein each row includes a side edge portion having a leading face and an opposite trailing face, the leading face of a row confronting the trailing face of a leading row and the trailing face confronting the leading face of a trailing row, wherein the vibration dampers extends from at least one of the leading and trailing faces of at least every other row toward the confronting trailing or leading face of an adjacent row.

9. A modular conveyor belt as in claim 8 wherein the vibration dampers extend from both the leading and trailing faces of alternate rows.

10. A modular conveyor belt as in claim 8 wherein the vibration dampers extend from only one of the leading and trailing ends of every row.

11. A conveyor belt module comprising: a first hinge end and an opposite second hinge end defining respective first and second hinge axes transverse to a travel direction;

a plurality of first projections spaced apart along the first hinge end and a plurality of second projections spaced apart along the second hinge end and offset transversely from the first projections;

at least one of the first and second projections having a leading face extending transverse to the travel direction and an opposite trailing face;

a vibration damper protruding from at least one of the leading and trailing faces in the travel direction.

12. A conveyor belt module as in claim 11 wherein the vibration damper is made of a rubber or rubber-like material.

13. A conveyor belt module as in claim 11 wherein the vibration damper is bonded to the at least one of the leading and trailing faces.

14. A conveyor belt module as in claim 11 wherein the vibration damper is molded to the at least one of the leading and trailing faces.

15. A conveyor belt module as in claim 11 wherein the vibration damper protrudes through the at least one of the leading and trailing faces.

16. A conveyor belt module as in claim 11 wherein the conveyor belt module extends in width from a first side edge and a second side edge and wherein the vibration damper is disposed at at least one of the first and second side edges.

17. A conveyor belt module as in claim 11 wherein the vibration damper protrudes from both the leading and trailing faces.

18. A conveyor belt module as in claim 11 wherein the vibration damper protrudes from only one of the leading and trailing faces.

19. A method for making a conveyor belt module, comprising:

forming a conveyor belt module body having leading and trailing faces extending transverse to a travel direction of a conveyor belt made of such conveyor belt modules;

forming a rubber or rubber-like layer on at least one of the leading and trailing faces.

20. The method of claim 19 comprising forming the conveyor belt module body by injection molding the conveyor belt module body out of a thermoplastic polymer and forming the rubber or rubber-like layer by molding the rubber or rubber-like layer onto at least one of the leading and trailing faces.