GB2221440A - Conveyor belt cleaning apparatus - Google Patents

Abstract

In a conveyor belt cleaning apparatus including a scraper assembly which in use extends transversely of the conveyor belt, so that worn parts of the scraper assembly can easily be replaced, the assembly includes a plurality of scraper blades 120 each having a root end of inverted U-section to fit snuggly over a respective one of a number of cross bars 78 carried by blade carrying arms 76 connected to a cross shaft 60 by resilient means. <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. In particular, the invention relates to apparatus of this kind in which the scraper assembly includes a number of scraper elements independently and resiliently connected to a cross shaft carried between the free ends of locating arms or of other adjustable mounting structure.

It is known for example to mount respective scraper blades of the scraper elements to 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. This kind of arrangement works quite well but has one particular drawback, this being that when the scraper blades become worn down to such an extent that they need to be renewed, the replacement of the entire scraper assembly is a fairly expensive exercise.

The invention has for its object to at least alleviate this disadvantage.

According to one aspect of the invention, there is provided conveyor belt cleaning apparatus including a scraper assembly which in use extends transversely of the conveyor belt, said scraper assembly including a number of scraper blades independently and resiliently connected to a cross shaft carried between the free ends of locating arms or of other adjustable mounting structure, the scraper blades each having a root end portion of substantially inverted U-section to fit snuggly over a respective one of a number of cross bars carried by blade carrying arms connected to the cross shaft by resilient means. Preferably, the scraper blades will be of a composite construction, each including a synthetic plastics main body portion moulded onto the root end portion made of metal.A series of upstanding metal pins or the like will preferably be formed on the root end portion to provide an effective reinforcement for the main body portion of synthetic plastics material. Nut and bolt assemblies or the like will preferably be provided for insertion through aligned holes in the root end portions of the blades and in the cross bars.

According to another aspect of the invention, there is provided a set of scraper blades for renewing the blades of a scraper assembly of the kind referred to above, each scraper blade preferably being of a composite construction including a synthetic plastics main body portion moulded onto a root end portion made of metal.

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 embodying the invention, Figure 2 is a perspective view of a part of a scraper assembly forming part of the apparatus, and Figure 3 is a view similar to Figure 2 and which illustrates the way in which a scraper blade embodying the invention can be applied to an earlier construction of apparatus.

Referring now to the drawings, the apparatus there illustrated for cleaning a conveyor belt (shown in chain-dotted lines in Figure 1) includes a scraper assembly generally indicated 100 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 18 of respective fixing brackets 20, provided with apertured plates 22, which can be bolted to fixed frame structure (not shown) on 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 100 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.

The scraper assembly 100 includes a number of scraper elements 102 independently connected to a cross shaft 104 of square section bar which is carried between the free ends of the leaf springs.

Respective taper plug and socket fixings, generally indicated 106 are provided for connecting the opposite ends of the cross shaft 104 to the free ends of the respective leaf springs. The taper plug portions of the fixings are carried at the ends of respective lengths of hexagonal bar 108 and the latter extend non-rotatably through pairs of brackets 110,110 welded to the cross shaft and are axially located therein by screws (not shown).

Referring now in particular to Figure 2, each scraper element includes a length of square section metal tube 112 through which extends a respective mounting shaft 114 to which is welded a blade carrying arm 116 extending through a central slot in the tube 112. At the free ends of the blade carrying arms are welded respective cross bars 118 which carry respective scraper blades generally indicated 120. The square section metal tube 112 of each scraper element has a considerably larger internal dimension than the square section of the mounting shaft 114, as shown, but the clearance space is filled by a solidified mass of polyurethane which in operation of the cleaning apparatus acts as a resilient connection between the cross shaft 104 and the respective scraper blades.

The scraper blades, generally indicated 120, which are connected to the respective cross bars 118, are of a composite construction, each including a polyurethane main body portion 122 moulded onto a root end portion 124 made of metal.

As shown in Figure 2, each root end portion is of substantially inverted U-section to fit snuggly over the respective cross bar 118. A series of upstanding metal pins 126 welded to the root portion provide an effective reinforcement for the main body portion of polyurethane.

One side wall of each root end portion 124 of each scraper blade is slotted at 128 to accommodate the respective blade carrying arm where it joins the cross bar 118. On opposite sides of the slot 128 said root end portion is formed with holes 130 which extend completely through the root end portion and coincide with holes 132 in the cross bar 118 when the scraper blade has been mounted thereon. Nut and bolt assemblies 134 are provided for insertion through the aligned holes to retain the scraper blades on the cross bars.

It will be seen from Figure 1 that the blade carrying arms are of two different lengths so that alternate scraper blades are staggered. In other words there are two rows of scraper blades, one being located slightly in advance of the other.

The blades are of a width such that adjacent blades overlap, as shown.

Thus there is provided conveyor belt cleaning apparatus of the kind in which the scraper assembly includes a number of scraper elements independently and resiliently connected to a cross shaft, the arrangement being such that the scraper blades can be renewed when worn in a very simple and relatively inexpensive manner. All that is required is the removal of the nut and bolt assemblies 134 and the substitution of new scraper blades for the worn ones. The fact that the main body portions of the scraper blades are of polyurethane is advantageous in protecting the endless belt from damage but is not absolutely essential; the main body portions as well as the root end portions could be made of metal.

In Figure 3 there is illustrated the way in which a scraper blade embodying the invention can be applied to an earlier construction of apparatus.

As shown in Figure 3, the earlier construction of apparatus included a scraper blade 78 of rectangular shape welded to the free ends of blade carrying arms 76 projecting from a mounting shaft 74 (the mounting shaft extending through a solidified mass of polyurethane in a length of square section metal tube 72 welded to a cross shaft 60 as in the later construction described above). When worn down and requiring renewal, the scraper blade can be cut down, as shown, and the remaining part of the blade can be drilled so that, in effect, it becomes the cross bar 118 to which a scraper blade embodying the invention can be secured by means of a pair of nut and bolt assemblies 134. The scraper assembly of the earlier construction (substantially as shown in Figure 1 of our co-pending application for patent No. 87.24069) can be removed for modification in the manner just described and can then be replaced with a new set of scraper blades at a fraction of the cost of replacing the scraper assembly with a completely new assembly of the old type.

Claims (7)

CLAIMS:

1. Conveyor belt cleaning apparatus including a scraper assembly which in use extends transversely of the conveyor belt, said scraper assembly including a number of scraper blades independently and resiliently connected to a cross shaft carried between the free ends of locating arms or of other adjustable mounting structure, the scraper blades each having a root end portion of substantially inverted U-section to fit snuggly over a respective one of a number of cross bars carried by blade carrying arms connected to the cross shaft by resilient means.

2. Conveyor belt cleaning apparatus according to claim 1, in which the scraper blades are of a composite construction, each including a synthetic plastics main body portion moulded onto the root end portion made of metal.

3. Conveyor belt cleaning apparatus according to claim 2, in which a series of upstanding metal pins or the like are formed on the root end portion to provide an effective reinforcement for the main body portion of synthetic plastics material.

4. Conveyor belt cleaning apparatus according to any one of the preceding claims, in which nut and bolt assemblies or the like are provided for insertion through aligned holes in the root end portions of the blades and in the cross bars.

5. A set of scraper blades for renewing the blades of a scraper assembly as claimed in claim 1.

6. A set of scraper blades as claimed in claim 5, each scraper blade being of a composite construction including a synthetic plastics main body portion moulded onto a root end portion made of metal.

7. Conveyor belt cleaning apparatus constructed, arranged and adapted to be used substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.