WO2001010753A1

WO2001010753A1 - Modular conveyor chain

Info

Publication number: WO2001010753A1
Application number: PCT/US2000/021126
Authority: WO
Inventors: Roger H. Schroeder; Dennis A. Woyach
Original assignee: Rexnord Corporation
Priority date: 1999-08-11
Filing date: 2000-08-02
Publication date: 2001-02-15
Also published as: AU6619200A

Abstract

The present invention is directed to a link (13) that is adapted to reduce backline pressure when products accumulate on the carrying surface of one or more links in the conveyor chain. The links (13) embodying the present invention includes a body (16) that is connected on opposite sides with similar adjacent links (13). The body of the link (13) includes a plurality of spaced apart spherical bearings (20) that are supported by the body (16) such that there is free universal rotation between each bearing (20) and the body (16). A portion of each bearing (20) projects from the body (16) such that the protruding portions of the bearings (20) form a product-carrying surface for the conveyor chain.

Description

MODULAR CONVEYOR CHAIN

FIELD OF THE INVENTION

This invention relates to a conveyor chain, and more particularly to an improved chain link for use in constructing a conveyor chain.

BACKGROUND OF THE INVENTION Manufacturing and production facilities utilize conveyor chains to transport products or articles of production from one location to another. One of the more commonly used conveyor chains are modular link chains that include multiple widths of thermoplastic links or modules. The modular links typically include at least one link end which intermeshes with complementary spaced link ends projecting from an adjacent link or links. The individual modular links are typically similar in width and may be arranged in a bricked configuration. The intermeshing link ends are joined or hinged together by a connecting pin that permits the chain links to pivot with respect to each other. The chain links are joined together to form an endless conveyor chain that is typically driven by a sprocket. During operation of the conveyor, products are positioned on a carrying surface of the conveyor, and depending on the application where the conveyor is used, the products accumulate at one or more points on the conveyor. As the products accumulate, they push against each other to build up backline pressure. Large backline pressures are problematic when the products being carried by the conveyor are fragile because the products can be damaged as they push against each other. In addition, when the products are heavy, high backline pressure puts a strain on the conveyor and sprockets causing extensive wear to the components that make up the conveyor.

Some conventional modular conveyors include cylindrical rollers that are connected to one or more links in the modular conveyor. The rollers act as the carrying surface for the products being transported and rotate relative to the links as the products accumulate on the conveyor. The rollers permit the links to travel along the conveyor path while the products remain stationary. The rollers on each link provide support to the accumulated products until the links pass under the products. Once the links pass under the products, subsequent adjacent links move into place to provide support. Using rollers instead of having the carrying surface slide relative to the products reduces the amount of backline pressure that is generated when products accumulate on the carrying surface. U.S. Patent No. 4,880,107 discloses a conveyor chain that includes small closely- spaced rollers on the top carrying surface of the conveyor. The rollers facilitate the in-line transfer of articles being conveyed onto the carrying surface of a cooperatively associated transfer comb and/or conveyor belt. The rollers rotate about a shaft and reduce the backline pressure on the conveyor surface by allowing accumulated products to move backward along the carrying surface.

U.S. Patent No. 5,096,050 discloses a modular conveyor chain that includes rollers mounted onto shafts which are, in turn, mounted to the individual chain links. The rollers on the chain links rotate about the longitudinal axes of the supporting shafts and therefore reduce the backline pressure on the product conveying surface by allowing accumulated products to move backward along the carrying surface.

One of the problems associated with such conveyors is that they reduce backline pressure by permitting movement of accumulated products in only one direction (i.e., backward). While these conveyors reduce the backline pressure on accumulating products, they do not eliminate all of the backline pressure that negatively effects the operation of the modular conveyor.

Another problem associated with using conventional rollers in modular conveyors is that the rollers must rotate about a shaft that extends through the rollers. The need for support shafts makes manufacturing these types of modular links expensive. In addition, the shafts and rollers require considerable maintenance in order to keep the conveyor operating because the conveyors are difficult to clean and the rollers tend to jam if bits of material fall between the rollers.

Some additional conveyor chains that include links having rollers are disclosed in U.S. Patent Nos. 5,467,860, 5,224,583, 4,993,540 and 4,821,869. SUMMARY OF THE INVENTION The present invention is embodied in an improved link that is connected on opposite sides with similar links to form a conveyor chain. The improved link includes a body that supports a plurality of spaced apart spherical bearings such that there is free universal rotation between each bearing and the body. A portion of each of the bearings projects from the body such that the protruding portions form a product-carrying surface for the conveyor chain.

In one embodiment of the invention, the links in the conveyor chain are modular links. The modular links have a plurality of spaced link ends extending from opposite sides of the body. The link ends are adapted to intermesh with complementary spaced link ends projecting from a modular link or links in an adjacent row. The link ends include openings which are axially aligned and adapted to receive a connecting pin that runs through the openings to pivotally connect adjacent modular links together. In one form, the modular link bodies include a base and a cap such that the spherical bearings are positioned between the base and the cap when the base and the cap are secured together (e.g., by a snap-fit).

The ability of the spherical bearings to rotate in a universal direction with respect to the body of the link allows the products that accumulate on the conveyor to move in any direction (i.e., the path of least resistance). This freedom of movement minimizes the backline pressure on the conveyor. Minimizing backline pressure reduces the potential for damage to any fragile products being transported by the conveyor and also reduces the amount of wear to the links, pins and sprockets in the conveyor.

Accordingly, it is an object of this invention to provide a conveyor chain that minimizes the backline pressure caused by products accumulating on the carrying surface of the conveyor chain.

Another object of this invention is to provide a modular link for use in constructing a conveyor chain that includes a carrying surface which allows products that accumulate on the conveyor to move at any angle to the direction of product flow. Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings. WO 01/10753 „ PCT/USOO/21126

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BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a top view of the present invention in the form of a modular link of the present invention. Fig. 2 is a side view of the modular link of Fig. 1.

Fig. 3 is a top view of three rows of modular links in a conveyor chain having modular links positioned laterally adjacent to one another in a bricked configuration.

Fig. 4 is a perspective view of three adjacent modular links.

Fig. 5 is a top view of the three modular links of Fig. 4. Fig. 6 is a side view of the modular links of Fig. 4.

Fig. 7 is a section view of the modular links of Fig. 5 taken along line 7-7.

Fig. 8 is a top view of a base used to form the body in the link of Fig. 1.

Fig. 9 is a section view taken along the line 9-9 of the base of Fig. 8.

Fig. 10 is a section view taken along line 10-10 of the base of Fig. 8. Fig. 11 is a section view taken along line 11-11 of the base of Fig. 8.

Fig. 12 is a perspective view of a cap used to form the body of the link of Fig. 1.

Fig. 13 is a top view of the cap of Fig. 12.

Fig. 14 is a front view of the cap of Fig. 12.

Fig. 15 is a section view, similar to Fig. 7, of another form of the modular link. Fig. 16 is an enlarged section view of the modular link of Fig. 15.

DETAILED DESCRIPTION

Fig. 1 illustrates one form of a modular link embodying the present invention. The modular link 13 includes a link body 16 having a series of link ends 25 extending from opposite sides of the link body 16. The link ends 25 are transversely spaced from one another to define a series of spaces 27. Each link end 25 also includes an opening 33 (see Fig. 2) that is axially aligned with similar openings in the other link ends 25. The openings 33 in the link ends 25 can be cylindrical or elongated (not shown) in the direction of travel of the conveyor.

As shown most clearly in Figs. 3-6, the modular links 13 are adapted to be placed adjacent to other similar links 13 both laterally (see Fig. 3) and in the direction of conveyor travel (see Fig. 5). All of the modular links preferably have a similar shape such that the axially aligned openings 33 in the intermeshing link ends 25 receive a connecting pin (not shown) that hingedly connects the adjacent links 13 together.

The modular link 13 includes a plurality of spaced apart spherical bearings 20 (see Figs. 1-7). The spherical bearings 20 are supported by, and contained within, the link body 16 such that the spherical bearings 20 are able to rotate freely in any direction with respect to the link body 16.

Referring now particularly to Figs. 6 and 7, each of the bearings 20 includes a portion 21 that projects from a flat upper surface 22 of the link body 16. The bearings 20 project from the upper surface 22 of the link body 16 so that tops of the bearings 20 are positioned in a plane that defines a flat product supporting surface. This configuration ensures that the maximum number of bearings 20 provide support to the products carried by the conveyor chain. In the embodiment of the invention shown in Figs. 4 and 5, the spherical bearings 20 are arranged in two spaced apart parallel rows which extend transversely to the direction of conveyor travel. The bearings 20 are also staggered so that a bearing in one row is positioned midway between two bearings in the adjacent row. The bearings can be arranged in any configuration that facilitates product movement in order to reduce backline pressure.

The link body 16 may be a one-piece unit (see Figs. 15 and 16) or assembled from multiple pieces. In the multiple piece embodiment of the invention shown in Figs. 4, 6, and 7, the link body 16 includes a base 40 and a cap 41. The cap 41 is secured to the base 40 such that the portions 21 of the bearings 20 which protrude above the upper surface 22 of the link body 16 extend from the cap 41.

One form of the base 40 is illustrated in detail in Figs. 8-11. The base 40 includes the link ends 25 and a plurality of spherical surfaces 45 extending downward into the base 40 from a flat upper surface 42. The spherical surfaces 45 are adapted to receive the spherical bearings 20. The base 40 further includes cylindrical openings 46 extending downward from the spherical surfaces 45 further into the base 40. The cylindrical openings 46 are located below the spherical surfaces 45 in order to facilitate manufacturing the base 40 by injection molding. One form of the cap 41 is shown in greater detail in Figs. 12-14. The cap 41 includes a flat upper surface 47 and a flat lower surface 48. The lower surface 48 is adapted to mate with the upper surface 42 of the base 40. The cap 41 also includes a plurality of openings 50 in the upper surface 47 (see Fig. 7) and spherical surfaces 49 positioned adjacent to each opening 50. The spherical surfaces 49 extend upward from the lower surface 48 and are adapted to receive the bearings 20. The spherical surfaces 45 in the base 40 and the spherical surfaces 49 in the cap are aligned such that a spherical chamber is formed once the base 40 is secured to the cap 41. The diameter of the spherical chamber is slightly larger than the diameter of the bearings 20. The spherical surfaces 45, 49 are sized such that half of each bearing 20 is housed within the spherical surface 45 on the base and the remaining half of each bearing 20 is either housed within the spherical surface 49 of the cap 41 or projects through the opening 50.

The chamber formed by the spherical surface 45 and the spherical surface 46 is substantially spherical. The shape of the spherical surfaces 45, 49 may be modified in order to change the points of contact between the bearing 20 and the link body 16.

The cap 41 illustrated in Fig. 14 includes tooth-like projections 52 positioned on opposite sides of the cap 41. The projections 52 extend into the openings 53 in the base 40 (see Figs. 9 and 11) until the ends of the tooth-like projections 52 enter a recess 54 in the base 40. Once the projections 52 fully enter the recess 54, the projections 52 snap outward to secure the cap 41 to the base 40.

The base 40 and the cap 41 can take any configuration which facilitates connecting the cap 41 to the base 40. The base 40 and the cap 41 are preferably molded from a thermoplastic such as acetal, nylon, polypropylene, or polyethylene. In addition, the spherical bearings 20 are preferably made from either stainless steel, nylon or acetal and could project from a surface on the base 40 instead of the cap 41 depending on the design of the base 40 and cap 41.

Figs. 15 and 16 illustrate a one-piece link body 16. In this form, the spherical bearings are either molded within the link body 16 or press-fit into the link body 16 by inserting the spherical bearings 20 through an opening in an upper surface 60 of the link body 16. The openings in the upper surface 60 of the link body 16 communicate with spherical chambers that are adapted to receive the spherical bearings 20. The diameter of each spherical chamber is slightly larger than the diameter of each spherical bearing 20 while the diameter of each opening in the upper surface 60 of the link body 16 is smaller than the diameter of each spherical bearing 20. Since the diameter of each opening in the upper surface 60 of the link body 16 is smaller than the diameter of each spherical bearing 20, the spherical bearings are constrained within the link body 16 yet are permitted to universally rotate with respect to the link body 16.

The present invention is not limited to the embodiments shown and described above, alternate embodiments will be apparent to those skilled in the art and are within the intended scope of the present invention. In particular, it will be apparent to those skilled in the art to provide different types of links, including but not limited to, roller links and modular links that have less than a plurality of link ends extending from the body. In addition, it should be understood that the bearings can be arranged into a variety of different configurations. Therefore, the invention should be limited only by the following claims.

Claims

What is claimed is:

1. A link for use in constructing a conveyor chain, said chain link comprising: a body adapted to be joined with adjacent links; and a plurality of spaced apart spherical bearings supported by said body, said spherical bearings being supported by said body for free universal rotation with respect to said body, said bearings each including a portion that projects from said body to support a product on said portion.

2. The link of claim 1, wherein said body includes a single link end projecting from one side of said body and a pair of link ends extending from an opposite side of said body, said pair of link ends being adapted to intermesh with a single link end extending from an adjacent link and joined to the adjacent link by a hinge pin.

3. The link of claim 1 , wherein said body includes a plurality of spaced link ends projecting from opposite sides of said body, said plurality of spaced link ends being adapted to intermesh on each of said sides with adjacent links and joined with the adjacent links by hinge pins.

4. The link of claim 1, wherein said body includes a base and a cap with said bearings being supported between said base and said cap.

5. The link of claim 4, wherein said portions of said bearings project outside said cap.

6. The link of claim 4, wherein said cap is snap-fit to said base.

7. The link of claim 1, wherein each of said spherical bearings is aligned along an axis.

8. The link of claim 7, wherein said axis is transverse to the direction of conveyor travel.

9. The link of claim 1, wherein each of said bearings are aligned into a first row of bearings and a second row of bearings.

10. The link of claim 9, wherein said first row of bearings and said second row of bearings are parallel.

11. The link of claim 10, wherein said first row of bearings and said second row of bearings extend transversely to the direction of conveyor travel.

12. The link of claim 11, wherein each of said bearings in said first row is positioned substantially between each of said bearings in said second row.

13. A conveyor chain comprising: a plurality of links joined end to end, each of said links including a body; and a plurality of spaced apart spherical bearings contained within said body, said spherical bearings being supported by said body for free universal rotation with respect to said body, said bearings each including a portion that projects from said body to support a product thereon.

14. The conveyor chain of claim 13, wherein each of said plurality of links includes a link end projecting from one side and pair of spaced links projecting from an opposite side, said pair of spaced link ends being adapted to intermesh with a link end on an adjacent link.

15. The conveyor chain of claim 14 further comprising a plurality of hinge pins extending through axially aligned openings in the link ends to pivotally join adjacent links together.

16. The conveyor chain of claim 13, wherein each of said links includes a plurality of spaced link ends projecting from opposite sides such that said spaced link ends are adapted to intermesh with similar link ends on adjacent links, and further comprising a plurality of hinge pins, each of said hinge pins extending through axially aligned openings in the link ends to pivotally join adjacent links together.

17. The conveyor chain of claim 13, wherein said body includes a base and a cap with said bearings being supported between said base and said cap.

18. The conveyor chain of claim 17, wherein said portions of said bearings project outside said cap.

19. The conveyor chain of claim 17, wherein said cap is snap-fit to said base.

20. The conveyor chain of claim 13, wherein each of said spherical bearings is aligned along an axis.

21. The conveyor chain of claim 20, wherein said axis is transverse to the direction of conveyor travel.

22. The conveyor chain of claim 13, wherein each of said bearings are aligned into a first row of bearings and a second row of bearings.

23. The conveyor chain of claim 22, wherein said first row of bearings and said second row of bearings are parallel.

24. The conveyor chain of claim 13, wherein some of said links do not include said bearings.

25. A link for use in constructing a conveyor chain, said chain link comprising: a body adapted to join with adjacent links; and means for supporting products on the conveyor chain so that products which accumulate on the conveyor chain are able to move in any direction in order to reduce backline pressure on the conveyor chain.

26. The modular link of claim 25, wherein said means for supporting products on the modular conveyor chain includes a spherical bearing contained within said body so that a portion of said spherical bearing extends outside said body.

27. The modular link of claim 26, wherein said means for supporting products on the conveyor chain further includes at least one additional spherical bearing that includes a portion extending from said body.

28. The link of claim 25, wherein said body includes a link end projecting from one side and a pair of spaced link ends projecting from an opposite side such that said pair of spaced link ends are adapted to intermesh with a link end on an adjacent link.

29. The link of claim 25, wherein said body includes a plurality of spaced link ends projecting from opposite sides of said body, said plurality of spaced link ends being adapted to intermesh on each of said sides with adjacent links.