GB2239228A

GB2239228A - Conveyor belt cleaning apparatus

Info

Publication number: GB2239228A
Application number: GB9027034A
Authority: GB
Inventors: Septimus Hughes
Original assignee: Conveyor Improvements Doncaster Ltd
Current assignee: Conveyor Improvements Doncaster Ltd
Priority date: 1989-12-20
Filing date: 1990-12-13
Publication date: 1991-06-26
Also published as: GB9027034D0; GB8928744D0

Abstract

In a conveyor belt scraper having a scraper assembly extending across the width of the belt, in order that the scraper assembly may be either a multi-blade scraper assembly or a single blade scraper assembly, it includes a cross shaft 10, a plurality of mounting brackets 14 carried by said cross shaft, and a plurality of scraper blades and a single elongate scraper blade 150 which can be connected, selectively, to the mounting brackets. <IMAGE>

Description

Conveyor belt cleaning apparatus.

The invention relates to conveyor belt cleaning apparatus of the kind including a scraper assembly which in use extends transversely of the conveyor belt, the apparatus being attached to a fixed mounting structure, normally to frame structure of the conveyor mechanism.

There are two main types of scraper assembly, that is a first type in which a single scraper element extends the full width of the conveyor belt and is carried between the free ends of locating arms or of other adjustable mounting structure, and a second type in which the assembly includes a number of scraper elements independently and resiliently connected to a cross shaft carried between the free ends of the locating arms or other structure. Each of these two known types of scraper assembly are particularly well suited to certain working conditions. Broadly speaking, multi-blade scrapers are best suited to dry working conditions and single blade scrapers are best suited to wet conditions where the material being scraped off a conveyor belt can be likened to a slurry.

It is known to mount respective scraper blades of a multi-blade scraper assembly between blade carrying arms projecting from non-circular section mounting shaft elements projecting through lengths of square section metal tubes, each square section metal tube having a considerably larger internal dimension than the section of the mounting shaft and the clearance space being filled with a solidified mass of polyurethane which in operation of the cleaning apparatus acts as a resilient connection between the respective scraper blade and the cross shaft to which the square section metal tubes are welded. It is also known for each scraper blade to have a root end portion of substantially inverted U-section to fit snuggly over a respective one of a number of blade carriers carried by the blade carrying arms connected to the cross shaft by resilient means.

These kinds of arrangement work quite well but have one particular drawback, this being that, whichever kind of multi-blade arrangement is in use, when the scraper blades become worn down to such an extent that they need to be renewed, the replacement of the plurality of blades by a new set of blades is time consuming and therefore expensive. The invention has for its object to at least alleviate these disadvantages.

According to one aspect of the invention, there is provided a method of renewing the working efficiency of a multi-blade scraper assembly, the method including the steps of removing the individual scraper blades of the assembly and replacing them by a single scraper blade extending the full length of the assembly and connected at intervals along its length to the plurality of blade carriers.

According to another aspect of the invention, there is provided a scraper assembly for cleaning a conveyor belt, the assembly including a single scraper blade extending the full width of the conveyor belt but connected at intervals along its length to a plurality of blade carriers independently and resiliently connected to a cross shaft carried between the free ends of locating arms or of other mounting structure.

According to yet another aspect of the invention, there is provided a number of parts whereby a conveyor belt cleaning apparatus can be fitted, as required, with a multi-blade or single blade scraper assembly, the number of parts including a cross shaft for connection between the free ends of locating arms or of other adjustable mounting structure, a plurality of mounting brackets adapted to be carried by said cross shaft, a plurality of scraper blades adapted to be carried by respective mounting brackets, and a single elongate scraper blade of substantially the same overall length as said plurality of scraper blades when mounted side by side, the single scraper blade being adapted to be carried by the plurality of brackets in place of said plurality of blades.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which:- Figure 1 is a perspective view of conveyor belt cleaning apparatus of the kind to which the invention relates, Figure 2 is a perspective view, drawn to a scale slightly larger than Figure 1, of a multi-blade scraper assembly forming part of the apparatus, Figure 3 is an end view of the scraper assembly, Figure 4 is a view illustrating the way in which the scraper assembly has been assembled, and Figure 5 is a view similar to Figure 2 which illustrates how the scraper assembly can be converted into a single blade assembly.

Referring now to Figure 1 of the drawings, the apparatus there illustrated for cleaning a conveyor belt (shown in chain-dotted liners) includes a scraper assembly generally indicated 10 secured at its opposite ends to locating arms constituted by respective leaf springs 12 so as to bear against the underside of the belt.

The leaf springs 12 are mounted at their ends remote from the scraper assembly on respective mounting blocks 14 which are provided with respective stub shafts 16 of hexagonal cross section. The stub shafts extend rotatably through plain cylindrical bores of respective fixing brackets 20, provided with apertured plates 22, which can be bolted to fixed frame structure (not shown) of the conveyor concerned. Respective circular plates 26 are welded to the fixing brackets 20.

The circular plates 26 form part of respective detent means which are provided for releasably securing the mounting blocks in an angularly adjusted position. Each detent means includes a fixing lug 28 having a boss portion 30 with a hexagonal bore by means of which it can be located on the respective stub shaft 16. Each detent means also includes a locating peg 32 by means of which the respective fixing lug can be secured to the adjacent circular plate 26. As shown, each circular plate has a plurality of holes 34 arranged on two pitch circle diameters and in which the respective pegs can be engaged.Each fixing lug has two sets of three holes 36 and these are spaced apart in such a way that by their selective use the fixing lug concerned can be secured to the adjacent circular plate in angular increments of adjustment one sixth of those of the angular spacing of the holes in either one of the sets of holes 34 in the adjacent plate. The stub shafts are axially located by respective collars 38 capable of being fixed on said shafts by screws 40.

The mounting blocks 14 on which the leaf springs 12 are mounted are of composite construction, each block having an open ended metal casing 42 and a centrally located metal sleeve 44 for the location of the stub shaft 16, the space 46 surrounding the sleeve within the casing being filled with polyurethane. The metal sleeve 44 extends outwards from one side of the casing, as shown, and is provided with a screwthreaded hole for the reception of a locking screw 49 by means of which the stub shaft concerned can be axially located in the block. The part of the sleeve located within the width of the casing has been provided with four equally spaced welded on protuberances 50 (constituted by lengths of square. section material) so that these form an effective key within the mass of polyurethane.

One side of the metal casing of the block is provided with a welded on length of flat metal bar 56, this being apertured to receive bolts 57,57 for mounting the respective leaf springs thereon.

During the installation of the cleaning apparatus, the mounting blocks can be subjected to torsion, to appropriately pre-load the scraper assembly 10 against the conveyor belt concerned, by means of levers (not shown) which can be connected to the outer ends of the stub shafts 16. The appropriate amount of pre-load can be maintained in the installation by the use of the detent means referred to above.

Referring now to Figures 2 to 4, the scraper assembly 10 there illustrated, and forming part of the apparatus of Figure 1, includes a mounting shaft having a central shaft 110 of square section hollow tube on which has been moulded a square section sheathing of a synthetic plastics material 112, the external surfaces of the tube and of the sheathing being set at an angle of 450 to each other as shown. A plurality of scraper elements, generally indicated 114, are individually mounted side by side on the mounting shaft.

As best shown in Figure 3, each scraper element includes a length of square section hollow shaft 116 with an internal dimension such that it can be slide mounted on the square section sheathing of the mounting shaft. A mounting bracket 118 is welded to the length of hollow shaft 116 to provide a surface against which an upstanding blade carrier plate 122 is welded. A pair of abutment plates 126 welded to a back face of the blade carrier plate are arranged to abut as shown against the side surfaces of the mounting bracket so that the blade carrier plate is secured to said bracket in an upstanding condition.

Referring now to Figure 4, each scraper element includes a scraper blade 128 secured to the respective blade carrier plate by a pair of screws 130 with nuts 132. The opposite longitudinal edges of the scraper blade are both sharpened so that when one edge has become worn down the blade can be inverted to bring the other sharpened edge into use. An edge portion of a sheet 134 of a synthetic plastics material is sandwiched as shown between the blade and carrier plate for the remainder of the sheet to overlie the bracket 118, thus preventing the build-up of dirt thereon as the scraper blade scrapes dirt from the conveyor belt concerned.

When the scraper elements have been located side by side, each length of square section hollow shaft 116 having been slide mounted on the square section sheathing of the mounting shaft as shown in Figure 4, the operative scraper edges of the scraper blades 128 are located in line as shown in Figures 1 and 2. However, in this mode of use of the scraper assembly, each scraper element is capable of a certain amount of resilient movement on the mounting shaft relative to the remainder of the elements.

The opposite ends of the assembly are shown to have been provided with frusto-conical end pieces 136, these having been welded to the opposite ends of the central shaft 110. The frusto-conical end pieces form part of respective taper plug and socket fixings for securing the scraper assembly at a required angle betwen the pair of locating arms as shown in Figure 1, the locating arms being formed with the respective taper sockets 138 in which the end pieces are fitted and respective screws 146 being provided for engaging screwthreaded holes 137 in said end pieces for drawing the latter into tight engagement with the taper sockets.

Referring now in particular to Figure 5, this view indicates, diagrammatically, how the multiblade scraper assembly can be converted into a single blade scraper, either as a result of the plurality of blades having become worn down and needing replacement or when changing working conditions dictate. As shown, the method simply involves the removal of the plurality of individual scraper blades 128 and their replacement by a single elongate scraper blade 150 of substantially the same overall length as the plurality of scraper blades when mounted side by side. The single elongate scraper blade is provided with spaced pairs of holes 152 so that it can be secured to the respective blade carriers by means of the same pairs of nuts and bolts which previously secured the plurality of scraper blades in position.

Thus there is provided means whereby the working efficiency of a multi-blade scraper assembly can very simply be renewed or indeed whereby a scraper assembly can be made of either multi-blade or single blade type to suit changing working conditions. However, various modifications may be made. For example, the scraper assembly may be mounted in position in any convenient manner. It will also be understood that each scraper blade of the multi-blade scraper assembly could be secured to its respective mounting bracket by a single bolt located centrally of the blade and bracket, the single elongate scraper blade then having a correspondingly fewer number of holes 152.

Claims

CLAIMS:

1. A method of renewing the working efficiency of a multi-blade scraper assembly, the method including the steps of removing the individual scraper blades of the assembly and replacing them by a single scraper blade extending the full length of the assembly and connected at intervals along its length to the plurality of blade carriers.

2. A scraper assembly for cleaning a conveyor belt, the assembly including a single scraper blade extending the full width of the conveyor belt but connected at intervals along its length to a plurality of blade carriers independently and resiliently connected to a cross shaft carried between the free ends of locating arms or of other mounting structure.

3. A number of parts whereby a conveyor belt cleaning apparatus can be fitted, as required, with a multi-blade or single blade scraper assembly, the number of parts including a cross shaft for connection between the free ends of locating arms or of other adjustable mounting structure, a plurality of mounting brackets adapted to be carried by said cross shaft, a plurality of scraper blades adapted to be carried by the respective mounting brackets, and a single elongate scraper blade of substantially the same overall length as said plurality of scraper blades when mounted side by side, the single scraper blade being adapted to be carried by the plurality of brackets in place of said plurality of blades.

4. A method of renewing the working efficiency of a multi-blade scraper assembly, substantially as hereinbefore described with reference to the accompanying drawings.

5. A method of converting a multi-blade scraper assembly to single blade type, or vice versa, to suit changing working conditions, substantially as hereinbefore described with reference to the accompanying drawings.

6. A scraper assembly constructed, arranged and adapted to be used substantially as hereinbefore described with reference to and as illustrated by Figure 5 of the accompanying drawings.