Slides for endless belt conveyors

Slides for use on an endless belt conveyor belt and wear pads for use on slides for endless belt conveyors.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to slides for endless belt conveyors and wear pads for use on slides for endless belt conveyors.

2. Discussion of the Prior Art

Slides, which have been referred to as idlers have been used for some time to support conveyor belts. For example, U.S. Pat. No. 6,854,593 issued to Boudreau et al on Feb. 15, 2005, discloses a slide referred to therein as a pad-type idler, for slidably supporting a continuous conveyor belt. The pad-type idlers are supported on a metal support above a base. When conveying a liquid-containing substance, e.g. in the food processing industry, liquid falls onto the slides where it accumulates. The presence of a liquid between the belt and the slides results in drag (skin friction drag) between the belt and the slides which causes the belt to slow down or stop.

U.S. Pat. No. 5,799,780 issued to Steeb et al (hereinafter Steeb) on Sep. 1, 1998, discloses a slide, referred to therein as a wear bar, for slidably supporting a continuous conveyor belt. The first embodiment of Steeb is a feed idler assembly, which includes a generally U-shaped frame defined by a base, a pair of legs on opposite ends of the base and a pair of shorter intermediate supports between the legs. Plates are attached to the top ends of the legs of the intermediate supports. Wear bars are attached to the tops of the plates. A conveyor belt sliding over the wear bars forms a trough which is useful for conveying materials in the manufacturing and mining industries.

The fixed wear bars of Steeb are intended to replace rotatable idler rollers. The Steeb patent discloses two different types of wear bars, namely those used for a feed idler assembly (seeFIGS. 8ato8cin particular) and one for a return idler assembly (seeFIGS. 11ato11c). The feed idler wear bar has a flat top surface and tapered side surfaces. The return idler is a flat plate. The Steeb return idlers cause the edges of the conveyor belt to wear, because the belt has a slightly bowed profile upon its return and accordingly contacts the edges of the return idlers.

GENERAL DESCRIPTION OF THE INVENTION

In one aspect, the invention relates to a wear pad for use on a slide of an endless track conveyor belt comprising an elongated body having a flat top surface for slidably supporting a conveyor belt during travel of the belt over the top surface between leading and trailing edges of the top surface; and a plurality of grooves in said top surface extending between the leading and trailing edges of the body for discharging liquid falling onto the top surface, whereby drag between the wear pad and the belt is reduced.

In another aspect, the invention relates to a slide for use on an endless belt conveyor, said slide comprising a crossbar extending perpendicular to the path of travel of the endless belt; and a wear pad on said crossbar for supporting said belt during travel of the belt, said wear pad extending perpendicular to said path of travel; a spacer between said pad and said crossbar for spacing said pad from said crossbar; and retaining means for retaining said pad and spacer on said crossbar.

In another aspect, the invention relates to a slide for use on an endless belt conveyor, said slide comprising a crossbar extending perpendicular to the path of travel of the endless belt; the top of said crossbar having a hole therethrough; a wear pad on said crossbar for supporting said belt during travel of the belt, said wear pad extending perpendicular to said path of travel and having a threaded hole therethrough, a synthetic fluorine-containing resin bolt in said threaded hole extending through said hole in said crossbar; and locking means for retaining said pad on said crossbar.

In another aspect, the invention relates to a return slide for use on an endless belt conveyor, which includes a pair of rollers and an endless belt extending around said rollers, said slide comprising a base for extending perpendicular to the path of travel of the endless belt beneath said rollers; and a wear pad on said base for supporting said belt during travel of the belt beneath said rollers, said wear pad having a top surface which is convex along its length for positioning beneath an endless belt with the pad extending perpendicular to said path of travel.

In another aspect, the invention relates to a hanger assembly used for suspending a return slide from an endless belt conveyor frame comprising a hanger plate having a top end for suspending the hanger from the conveyor frame; a bottom end for supporting one end of a return slide; a keyhole slot in said bottom end for receiving a bar for connecting the hanger plate to one end of a return slide; and a clip for locking said bar in said slot.

In another aspect, the invention relates to a hanger assembly used for suspending a return slide from an endless belt conveyor frame comprising a hanger plate having a vertical top end portion; a flange on said top end portion for suspending the hanger from the conveyor frame; a web connected at one end to a lower end of said top portion for extending inwardly towards one end of a conveyor slide; a vertical bottom end portion connected to a second end of said web, a keyhole slot in said bottom end portion for receiving a bar for connecting the hanger plate to one end of a return slide; and a clip for locking said bar in said slot.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIG. 1, the slides and wear pads of the present invention are intended for use in a conveyor assembly of the type including an inclined endless belt for receiving material to be conveyed from a chute2located above the belt. The belt1passes around a tail pulley3and a driven head pulley4. The pulleys3and4include axles6and7mounted in pillow block bearings8and9, respectively. The bearings8and9are mounted on the ends of a frame indicated generally at10, which includes a plurality of legs12and sides13(one shown) supported by the legs.

During travel over the top of the pulleys3and4, the belt1is supported by transition slides14and troughing slides15. When passing beneath the pulleys3and4the belt is supported by return slides17. Each of the transition and troughing slides14and15includes a frame defined by a tubular base18with plates19on the ends thereof for mounting the assembly on the main frame10of the conveyor. The top ends of vertical center posts21extending upwardly from the middle of the base18are interconnected by a crossbar22.

A wear pad24in accordance with the present invention is mounted on the crossbar22. Inclined wear pads25are mounted on arms26connected to and extending outwardly and upwardly from the ends of the crossbar22. Inclined side posts28extend between the base18and the arms26for supporting the latter. The basic difference between the transition and troughing slide assemblies14and15is the angle of the inclined wear pads25with respect to the horizontal. The troughing wear pads and the supporting arms26have a greater inclination for forming a deep material conveying trough. The wear pads24and25, which are formed of a Teflon (trade-mark for polytetrafluoroethylene) composite, are similar to the pads disclosed by U.S. Pat. No. 6,854,592, issued Feb. 15, 2005.

The pad24can optionally include cylindrical or frusto-conical wear indicators of the types described in applicant's Canadian Patent Application 2,327,646 and U.S. Pat. No. 6,854,593, respectively and which are incorporated herein by reference.

Referring toFIGS. 2 to 6, the wear pad24in accordance with the present invention is basically an elongated rectangular parallelepipedic body with a flat, rectangular bottom surface29and a flat rectangular top surface30over which the belt1slides. The top of the front and rear ends31(the leading and trailing ends in the direction of belt travel) of the pad24are beveled. Holes32in the pad24receive bolts33for mounting the pad on the crossbar22. The pad is spaced apart from the crossbar22by a pair of spacers35. The bolts33extend through the spacers35and the crossbar22. Nuts36are threaded onto the bottom ends of the bolts33beneath the crossbar22.

As mentioned above, when conveying liquid-containing material, e.g. in the food processing industry, liquid tends to accumulate on the wear pads24. The liquid literally sucks the belt1against the pads24which can slow down or stop the belt. Drag on the belt by the liquid is reduced by providing a plurality of grooves or channels38extending between the leading and trailing edges (in the direction of belt travel) in the top of each pad24. Liquid landing on the pads24is discharged via the grooves38. While the dimensions of the pad24and the grooves38are not critical, in a thirty inch long pad, three 0.25 by 0.25 inch grooves38spaced slightly over an inch apart in the center of the pad are effective. Of course, additional grooves with different dimensions can be used in the top of the pad24.

The wear pad24can also be mounted on the arms26in place of the wear pads25.

It will be appreciated that while the wear pad of the present invention has been described in a particular environment, i.e. on a specific slide assembly, the wear pad can be used on different endless belt conveyor slides. Moreover, the number of grooves and the dimensions thereof can vary depending upon, inter alia, the belt width and the speed of belt travel over the pads.

Referring toFIG. 7, in another embodiment, a wear pad125, in accordance with the present invention, does not include grooves but otherwise has all of the same elements as wear pad24shown inFIGS. 3 to 6and described above and can be used in place of wear pad24on conveyor assemblies of the type shown inFIG. 1and described herein.

Referring toFIGS. 8 to 14, in another embodiment, wear pad32and crossbar34can be used in place of wear pads24and25and crossbar22and arm26respectively in a conveyor assembly of the type shown inFIG. 1and described herein.

The wear pad32has a rectangular main top surface36which contacts the belt4. The top side edges38of the wear pad32are bevelled while the bottom surface40is rectangular. Two threaded holes42are provided in the wear pad32for receiving a bolt44. The bolt44is made from Teflon suitable for use in the food industry. The bolt44includes a threaded section46and a cylindrical head46. The base48includes a bore50therethrough for receiving a cotter pin52.

The wear pad32can optionally include cylindrical or frusto-conical (indicated by33) wear indicators of the types described in applicant's Canadian patent no. 2,327,646 and U.S. Pat. No. 6,854,593 respectively and which are incorporated herein by reference.

The crossbar34is made from steel and is generally c-shaped in cross section and includes two holes54(one toward each end of the crossbar34in a similar fashion to holes30in crossbar10) for receiving bolts44.

To mount the wear pad32, a bolt44is screwed into each threaded hole42.

The wear pad32is then mounted on the crossbar34by dropping the base48of the bolts44into the holes54. A cotter pin52inserted into each bore50prevents the wear pad32from being removed from the crossbar34.

With reference toFIGS. 16 and 17, return slides17in accordance with the invention, can be used with a conveyor assembly of the type described with reference toFIG. 1. Each return slide17includes an elongated steel base30having a generally C-shaped cross section. The base130is arcuate, i.e. upwardly bowed or convex when viewed from the front or rear. A wear pad131mounted on the base130is also convex when viewed from the front or rear. Longitudinally extending grooves133in the sides of the pad131receive inverted L-shaped brackets134for retaining the pad on the base130. The brackets134are welded to the sides135of the base130. The use of a return pad131with a top surface, which is convex in a direction perpendicular to the direction of travel of the conveyor belt1beneath the pulleys3and4substantially reduces wear on the edges of the belt. It will be appreciated that, when passing around the driven pulley4, the belt1tends to be concave even after the contents of the belt have been dropped. Thus, when it passes beneath the pulley4, the belt1tends to define a shallow, transversely extending inverted trough. The slide131accommodates this belt configuration, reducing belt wear. It will also be appreciated that neither the base130nor the wear pad131need be arcuate. It is merely necessary for the top, belt engaging surface of the pad131to be bowed upwardly perpendicular to the path of travel of the belt1beneath the pulleys3and4.

The base130is suspended from the sides13of the conveyor frame10by hangers137. As best shown inFIG. 18, each hanger137includes a metal plate which is bent to define a large downwardly tapering, vertical top end140, a central inclined web142and a smaller downwardly tapering bottom end143. A rectangular flange144extends inwardly over the web142at the top of the hanger. Holes145in the flange144receive bolts or screws (not shown) for suspending the hangers from the frame sides2.

A keyhole slot147in the bottom end143of the hanger receives one end148of a short bar149, the other end150of which supports one end151of the slide base130. In the use position, the outer end148of the bar149is horizontal, and the inner end150is inclined slightly upwardly to match the slope of the base130. The outer end148of the bar149includes diametrically opposed flats, i.e. notches153for locking the bar in the slot146.

Referring toFIG. 20, a novel clip55for locking the hanger137on the bar149includes a generally C or boomerang-shaped thin metal body with a horizontal top arm56and an inclined bottom arm57. A threaded hole59in the top arm56receives a screw61, and a hole62in the arm57at the bottom of the vertical corner63of the body receives a rivet65. When the bar149is in the narrow bottom of the keyhole slot147and the clip55is in position with the top arm56extending over the bar, the bar149is locked in position and cannot escape from the hanger. When the conveyor is being transported from one location to another, the return slide can be dislodged from the hangers137, i.e. the bar148can bounce out of the slot147in the hanger. The clip55prevents such accidental release of the slide.

If the return slide or a portion thereof is to be replaced, the slide can be removed from the hangers137by removing the screws61and lifting the slide. The bars149cause the clips55to pivot around the rivets65to release the slide. The rivets65are long enough to permit the clip to rotate, but sufficiently short that when rotated by the bars149the bottom arm57of the clip remains in position covering the bottom end of the keyhole slot147. When the bars149are inserted in the slots147and lowered, the bars engage the arms57to cause the clips to rotate to the bar locking positions. The screws61are replaced in the holes59to lock the return slide in the hangers137.

It will be appreciated by those skilled in the art to which the present invention relates that the clip55can be used with hangers for suspending straight return slides or even roller assemblies from a conveyor frame.