Flat wire conveyor belt system

A flat wire conveyor belt system includes a plurality of spaced tractive rods and a plurality of rows of pickets transversely disposed with respect to a direction of travel and interconnecting the plurality of spaced tractive rods, each of the rows of pickets including a plurality of first links and a plurality of second links, the plurality of first links have a first spacing and the plurality of second links have a second spacing, the first spacing being less than the second spacing. The system further includes a sprocket, wherein the plurality of first links are configured to engage the sprocket teeth thereof.

FIELD OF THE INVENTION

The present invention is directed to a conveyor belt, more particularly to a flat wire conveyor belt having variable spaced wire links, and still more particularly, to a flat wire conveyor belt system having variable spaced wire links that are designed to be engaged by dual tooth sprockets.

BACKGROUND OF THE INVENTION

Flat wire conveyor belts have been in the market for many years. Flat wire conveyor belts are generally low maintenance and when positively driven with sprockets have little to no lateral shifting. With reference toFIG. 1, U.S. Pat. No. 2,619,306 discloses a flat wire conveyor belt10comprising a plurality of pickets16, sometimes also referred to as wickets, and interconnecting rods18about which the pickets hinge. The pickets16on belt10support the product to be conveyed and the rods18are utilized to hold the components of belt10together.

In a straight run, when a sprocket tooth is disposed within an opening defined by a link in the picket, the sprocket tooth relieves the tension in the adjacent pickets and concentrates it one location, thereby causing rod18to deflect at the sprocket tooth. This in turn causes the link in the picket which surrounds the sprocket tooth to become more highly loaded. Hence, fatigue and breakage may occur at one or more of the link areas surrounding a sprocket tooth where rod18meets picket16.

Fatigue breakage at one or more of the picket areas of a flat wire conveyor belt is a function of the number of cycles that a particular area is flexed. This problem becomes even more pronounced as the conveyor belt becomes lighter in weight and more open.

U.S. Pat. No. 5,950,807 is a light duty conveyor belt constructed from round wire elements that only partially hinge and thereby flex due to interferences between the wire elements. The '807 patent attempts to increase load carrying ability of the conveyor belt without increasing weight by using alternating small and large openings in the belt. While this may marginally improve the strength of the belt, the belt still experiences rapid failure because of the inability of the wire elements to truly binge freely, and the belt still has a tendency to deflect when driven by sprockets which imparts fatigue loading to the wire elements, resulting in wire breakage.

Accordingly, there exists a need in the marketplace for a flat wire conveyor belt having a lighter weight and reduced quantity of required material; thus reducing the cost, while still retaining its strength so as to avoid fatigue failure.

SUMMARY OF THE INVENTION

These and other objects are met by a variable spaced conveyor belt system including a plurality of spaced tractive rods and a plurality of rows of pickets transversely disposed with respect to a direction of travel and interconnecting the plurality of spaced tractive rods. Each of the rows of pickets includes a plurality of first links and a plurality of second links, the plurality of first links having a first spacing and the plurality of second links having a second spacing. The system further includes a sprocket, wherein the plurality of first links are configured to engage the sprocket teeth thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A conveyor belt in accordance with the present invention is shown generally inFIG. 2by reference numeral100. Conveyor belt100preferably comprises a flat wire conveyor belt including a plurality of spaced tractive rods180disposed in succession and transversely with respect to a direction of travel T as represented by arrow T of belt100, each rod180having two ends200and210.

Belt100includes a plurality of rows of pickets160transversely disposed with respect to the direction of travel T, and interconnecting the succession of rods180. Each row of pickets160is comprised of a plurality of links300, each link connecting a rod180with a following rod in the succession.

In accordance with a first preferred embodiment of the present invention, pickets160comprise a plurality of links300; however, not all the links300within a single picket are identical. More particularly, in order to strengthen the outer edges of the conveyor belt, the edges120,130of the picket are provided with links310having a first spacing or mesh size and the middle portion of the belt therebetween is provided with links320having a second spacing or mesh size. The exact number of links310or mesh openings on each end of the picket may vary depending upon the weight of the belt and other conditions. By way of example, picket160shown inFIG. 2includes link310defining one open mesh area on each end of the picket whereas pickets160′ and160″ shown inFIGS. 3 and 4, respectively, include two links310defining four open mesh areas on each end thereof for cooperation with a dual tooth sprocket, as discussed further below.

In a preferred embodiment, the spacing of the links310is less than the spacing of the links320such that the edges of the conveyor belt are reinforced by being more dense, heavier, and stronger. As shown inFIG. 2, links310are formed, preferably, having a conventional 1×1 spacing, that is, the mesh opening defined by the links310is 1″ in the lateral direction and 1″ in the longitudinal direction, On the other hand, links320are spaced further apart in a 3×1, 4×1, or similar pattern, that is, the opening defined by the links320is 3″ or 4″ in the lateral direction and 1″ in the longitudinal direction. By spacing the links in the middle portion further apart, the weight of the picket is reduced and thus, the overall weight and material need for the conveyor belt are reduced. One skilled in the art will recognize that 3×1 and 4×1 are merely examples of link spacing and other spacing patterns could be used to even further reduce the weight of the belt. Similarly, while the 1×1 pattern is illustrated for links310, a conventional ½×1 pattern could also be used depending upon the fatigue conditions, or still further, any mesh opening between the ½×1 and the 1×1 could be used depending upon the intended dimensions of the sprocket teeth.

FIG. 3discloses a further preferred embodiment in which picket160′ having multiple links310disposed on each edge120,130so as to define tension bearing elements, and one or more links310disposed in one or more locations in the middle region of the picket. By providing one or more, preferably two, of the denser, more closely spaced links310on the edges and in the middle of the picket160′, the weight of the overall conveyor belt is not significantly increased and the denser links310, when engaged by sprocket teeth, are able to assist in spreading the load over a greater width of the belt and reduce deflection by balancing the forces imparted by the adjacent teeth.

FIG. 4illustrates yet a further preferred embodiment of the present invention, wherein picket160″ includes links310on each edge120,130and the middle portion, and further includes links330having a greater width than both links310and320. More particularly, the sections of the belt nearest to the sprocket locations, i.e., links310, are narrower than the remaining sections of the belt in or to decrease deflection in the fatigue prone region of the belt.

Referring toFIG. 5, a sprocket200in accordance with a preferred embodiment of the present invention is shown. Sprocket200is a dual tooth sprocket in that the each outer peripheral edge includes a row of sprocket teeth210, with a smooth supporting surface220disposed therebetween. The ability to use a double tooth sprocket allows the belt to be more evenly loaded across the width and the narrow links310permit there to be less deflection at the drive engagement points. While a dual tooth sprocket is preferred, one skilled in the art will appreciate that two narrow sprockets with a single row of teeth could also be used to engage the narrow links310of the belt100. As illustrated inFIG. 6, the sprocket teeth210engage the second and forth open areas (counting from left to right in the illustration) defined by links310of the conveyor belt100, while the supporting surface220supports the open area disposed therebetween. The first open area defined by link310on each edge of the conveyor belt is preferably not used to engage sprocket teeth since the edges of the conveyor belt are already the most susceptible to damage and fatigue. In accordance with the present invention, the number and spacing of the sprocket engagement points can be varied depending upon the application and desired product loads.

The above-described embodiments illustrate preferred relationships between links within a picket configured for use with a dual tooth sprocket. Such descriptions are not limited to the illustrated lineal pitch, and can of course be used with any desired pitch. Similarly, the pickets and hence the conveyor belts can be manufactured to any preferred width depending upon the desired application. During the manufacturing process of the conveyor belt100, each picket will have fixed openings in the picket, i.e., the even numbered openings, and variable openings, i.e., the odd numbered openings, that may be adjusted slightly in order to meet the customer demands. More particularly, the openings of all the links310are referred to as 1×1, yet the odd numbered links310may in actuality be 0.75×1 or 1.2×1 in order to render a finished conveyor belt having the desired width. Thus, for purposes of the present invention, links310are understood to be substantially similar is spacing even though manufacturing constraints may require slight variations from the specified width. This of course also applies to links320and330.

While the present invention has been described with respect to a particular embodiment of the present invention, this is by way of illustration for purposes of disclosure rather than to confine the invention to any specific arrangement as there are various alterations, changes, deviations, eliminations, substitutions, omissions and departures which may be made in the particular embodiment shown and described without departing from the scope of the claims.