GB1570287A

GB1570287A - Surface cleaning device

Info

Publication number: GB1570287A
Application number: GB5056075A
Authority: GB
Original assignee: Brockway Engineering Co Ltd
Current assignee: Brockway Engineering Co Ltd
Priority date: 1977-02-08
Filing date: 1977-02-08
Publication date: 1980-06-25

Description

(54) SURFACE CLEANING DEVICE (71) We, BROCKWAY ENGINEERING COMPANY LIMITED, of Lowndes Road, Stourbridge, West Midlands, a British Com- pany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a device for cleaning a surface, such as the load bearing surface of a conveyor belt.

The present invention consists in a device for cleaning a surface having relative movement thereto comprising a scraper element mounted for rotation about an axis extending at least partially across the said surface, said element having an edge extending circumferentially about the axis and making an acute angle with a plane containing the said axis, said plane extending normal to the said surface and at an angle to the direction of relative movement, whereby the said edge makes contact with the said surface at an angle to the direction of relative movement.

Preferably the angle made by the edge of the plane containing the axis is in the same sense as the angle made by the said plane to the direction of relative movement.

In other arrangements, the element may be rotated so that its peripheral speed is different from the relative speed between the device and the surface. The speed of the element may be slower, by retarding the rotary movement of the element, or the device may be driven either in the opposite direction to that of the relative movement or in the same direction and at a greater speed.

Normally the device will be stationary and it will be the surface which moves, as in the type of construction with which this invention is particularly concerned wherein the device is arranged to clean the surface of the return run of a conveyor belt.

Preferably the device comprises a roller of which the rolling surface is constituted by the edge or edges of one or more scraper elements. The roller of the device may comprise a series of discs in one example but preferably, the roller of the device comprises a scraper element of helical form.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying draw- ings in which: Figure 1 is a front view of a device according to the invention, shown mounted to the support framework of a conveyor belt of which the lower return run of the belt is shown lying on the device.

Figure 2 is a plan view of the device shown in Figure 1 with the conveyor belt removed, and Figure 3 is an end view of the device as shown in Figure 1.

The device shown in the drawings is arranged to clean the load bearing surface of a conveyor belt 10 for which purpose it is arranged below the return run of the conveyor belt which is partially supported by the device, and the device, for this purpose, may be a replacement for a normal idler return roller arrangement.

The device oomprises two rollers 11, 12 each comprising two scraper elements 13, 14 each of which is in the form of a helix of wire. The two helic elements 13, 14 of each roller 11, 12 are intermeshed so as to be in the form of a two start screw-thread.

The two elements of each roller 11, 12 are supported on three rods 15 which extend between two annular end plates 16 to which they are connected at equal distances apart.

At each end of the roller a dished circular carrier plate (not shown) is welded to the rods 15 and each carrier plate has an axle portion (not shown) mounted for rotation in a bearing assembly 19.

The two rollers 11, 12 are mounted in a support frame 20 comprising support brackets 21 having notches 22 in which the outer housings of the bearing assemblies 19 are located. The support frame also comprises two tubes 23 disposed parallel to one another and secured at their ends to flanges of respective angle-section members 24 bolted or otherwise secured to strut members 25 of a conveyor belt support framework. The bearing support brackets 21 at the middle of the device are formed from a single plate of U-shaped cross-sectional shape the free ends of which are secured to the two tubes 23 and the outer bearing support brackets 21 are welded to the respective angle-section members 24.

As shown in Figure 2 each element 13, 14 has an angled contact with the surface of the belt 10. This is due to the angle of the plane normal to the surface in which the axis of rotary movement of the rollers 11, 12 and thus of the scraper elements 13, 14 lies with respect to the direction of movement of the belt relative to the device and due to the helix angle of the elements 13, 14. This angled contact is such that if the element were to be rolled about that axis along the surface, unconstrained laterally it would trace notionally a line on that surface at an acute angle to the direction of relative movement. In this way a transverse scraping action occurs between each scraper element 13, 14 and the belt 10 when, as in use, lateral movement is prevented.

The axes of rotary movement of the two rollers are oppositely inclined relative to the direction of belt movement and the helical scraper elements of the rollers are oppositely handed so that the lateral thrust of the one is equal and opposite to that of the other and there are no resultant transversely directed forces to be transmitted to the start members of the framework of the conveyor from the device.

The open framework construction of the rollers formed by the wire helices and supporting rods employed in this particularly described embodiment enables debris cleaned from the belt to fall free of the device.

In general, the greater the helix angle of a helical element, the greater the scraping action. The angle of contact between each scraper element and the surface due to the disposition of the element relative to the axis of rotary movement, i.e. the helix angle in this particularly described embodiment, is preferably supplementary to the angle of contact imposed by the angle of the plane containing the axis of rotary movement of the scraper element relative to the direction of relative movement between the device and the surface; as in the embodiment shown in the accompanying drawings.

In any construction of device according to the invention the number of scraper elements in contact with the width of the belt is desirably as large as possible commensurate with the existance of gaps within the element large enough to permit clearance of debris detached from the belt: thus the number of starts of the helices in any roller has to be increased when the helical angle is increased. The particular optimum arrangement of number of starts of helices, heljcal angles and angles of inclination of the rollers for any arrangement of a device according to the invention has to be deter- mined for the particular task of cleaning it is required to perform.

In other constructions of device in order that the whole width -of the belt is subject to the scraping action of the device, the inboard ends of the rollers may be arranged to overlap one another or two rollers can be arranged each to extend across the total width of the belt but be disposed one behind the other relative to the movement of the belt.

In the construction described with reference to the accompanying drawings, the wire helices forming the scraper elements 13, 14 are indicated as being formed from wire of circular cross-sectional shape. In another, similar construction, the wire forming the helices is of rectangular - cross-sectional shape oriented so as to present a corner of that shape for contact with the bolt. In such a construction, there is a sharp line contact between the element and the belt.

WHAT WE CLAIM IS:- 1. A device for cleaning a surface having relative movement thereto comprising a scraper element mounted for rotation about an axis extending at least partially across the said surface, said element having an edge extending circumferentially about the axis and making an acute angle with a plane containing the said axis, said plane extending normal to the said surface and at an angle to the direction of relative movement, whereby the said edge makes contact with the said surface at an angle to the direction of relative movement.

2. A device according to claim 1 Where- in the angle made by the edge to the plane containing the axis is in the same sense as the angle made by the said plane to the direction of relative movement.

3. A device according to claim 1 or claim 2 comprising a roller of which the rolling surface is formed by the edge or edges of one or more scraper elements.

4. The device according to claim 3 wherein the roller is driven.

5. A device according to claim 2 or 3 in which the roller has its rolling surface formed by a scraper element in the form of a helix.

6. The device of claim 5 and comprising another scraper element in the form of a helix, the elements being intermeshed so as to be in the form of a two-start screw thread.

7. The device of any one of preceding claims 3 to 6 and including another roller, the rollers being constructed and arranged

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. bolted or otherwise secured to strut members 25 of a conveyor belt support framework. The bearing support brackets 21 at the middle of the device are formed from a single plate of U-shaped cross-sectional shape the free ends of which are secured to the two tubes 23 and the outer bearing support brackets 21 are welded to the respective angle-section members 24. As shown in Figure 2 each element 13, 14 has an angled contact with the surface of the belt 10. This is due to the angle of the plane normal to the surface in which the axis of rotary movement of the rollers 11, 12 and thus of the scraper elements 13, 14 lies with respect to the direction of movement of the belt relative to the device and due to the helix angle of the elements 13, 14. This angled contact is such that if the element were to be rolled about that axis along the surface, unconstrained laterally it would trace notionally a line on that surface at an acute angle to the direction of relative movement. In this way a transverse scraping action occurs between each scraper element 13, 14 and the belt 10 when, as in use, lateral movement is prevented. The axes of rotary movement of the two rollers are oppositely inclined relative to the direction of belt movement and the helical scraper elements of the rollers are oppositely handed so that the lateral thrust of the one is equal and opposite to that of the other and there are no resultant transversely directed forces to be transmitted to the start members of the framework of the conveyor from the device. The open framework construction of the rollers formed by the wire helices and supporting rods employed in this particularly described embodiment enables debris cleaned from the belt to fall free of the device. In general, the greater the helix angle of a helical element, the greater the scraping action. The angle of contact between each scraper element and the surface due to the disposition of the element relative to the axis of rotary movement, i.e. the helix angle in this particularly described embodiment, is preferably supplementary to the angle of contact imposed by the angle of the plane containing the axis of rotary movement of the scraper element relative to the direction of relative movement between the device and the surface; as in the embodiment shown in the accompanying drawings. In any construction of device according to the invention the number of scraper elements in contact with the width of the belt is desirably as large as possible commensurate with the existance of gaps within the element large enough to permit clearance of debris detached from the belt: thus the number of starts of the helices in any roller has to be increased when the helical angle is increased. The particular optimum arrangement of number of starts of helices, heljcal angles and angles of inclination of the rollers for any arrangement of a device according to the invention has to be deter- mined for the particular task of cleaning it is required to perform. In other constructions of device in order that the whole width -of the belt is subject to the scraping action of the device, the inboard ends of the rollers may be arranged to overlap one another or two rollers can be arranged each to extend across the total width of the belt but be disposed one behind the other relative to the movement of the belt. In the construction described with reference to the accompanying drawings, the wire helices forming the scraper elements 13, 14 are indicated as being formed from wire of circular cross-sectional shape. In another, similar construction, the wire forming the helices is of rectangular - cross-sectional shape oriented so as to present a corner of that shape for contact with the bolt. In such a construction, there is a sharp line contact between the element and the belt. WHAT WE CLAIM IS:-

1. A device for cleaning a surface having relative movement thereto comprising a scraper element mounted for rotation about an axis extending at least partially across the said surface, said element having an edge extending circumferentially about the axis and making an acute angle with a plane containing the said axis, said plane extending normal to the said surface and at an angle to the direction of relative movement, whereby the said edge makes contact with the said surface at an angle to the direction of relative movement.

4. The device according to claim 3 wherein the roller is driven.

so that the lateral thrust of the one is equal and opposite to that of the other.

8. A device for cleaning a surface and substantially as described herein with reference to and as shown in the accompanying drawings.