GB2282787A

GB2282787A - Conveyor belts.

Info

Publication number: GB2282787A
Application number: GB9320355A
Authority: GB
Inventors: Alan William Atkinson; David Richard Bridge
Original assignee: T&N Technology Ltd
Current assignee: Federal Mogul Technology Ltd
Priority date: 1993-10-02
Filing date: 1993-10-02
Publication date: 1995-04-19
Anticipated expiration: 2013-10-02
Also published as: GB2282787B; GB9320355D0

Abstract

A conveyor belt (10) for use in transporting newly-moulded glassware comprises a glassware-engaging layer (14) made of heat-resistant metallic material. At least part of the layer is coated with particles (44) of heat-resistant material having dimensions up to 150 microns. The particles (44) form a coating (42) which increases the coefficient of friction so that glassware is less likely to be pushed off the belt by cooling air jets. <IMAGE>

Description

Conveyor Belts This invention is concerned with conveyor belts which are suitable for use in transporting hot glassware. In particular, conveyor belts in accordance with the invention can be used to transport newly-manufactured containers made out of glass.

The most common machine used for manufacturing containers out of glass, is the individual section, or "IS" machine. An IS machine has a row of sections each of which operates to manufacture gobs of molten glass into containers. The sections are successively supplied with gobs from a common source and each deposits containers on a dead plate of the section which is located adjacent to a common conveyor belt of the machine. The conveyor belt runs parallel to the row of sections and acts to carry away containers from all the sections. Each section has a wipeout mechanism operable to sweep containers across the dead plate and on to the conveyor along an arcuate path at a speed which matches that of the conveyor belt as the containers arrive on the conveyor belt.

Since the containers arriving on the conveyor belt are hot and sticky, so that they can be easily marked, the conveyor belt has to be resistant to the temperatures involved, and have an upper surface which leaves no, or substantially no, impression on the containers.

Furthermore, in addition to having sufficient strength and flexibility, the conveyor belt must also not deliver a significant thermal shock to the containers so that a risk of damage to the containers is avoided. Present conveyor belts meet these criteria to varying degrees but none is entirely satisfactory.

Some conveyor belts are formed by a woven mass of glass fibres. Such a belt has limited heat resistance and can leave impressions on the glass particularly where a coarse weave is employed. Furthermore, in order to reduce friction, such belts often have to be impregnated with a lubricant, eg graphite, which is inconvenient and may lead to contamination of the glass.

It is also known to form such conveyor belts from woven metal wires. In order to provide sufficient strength, the wire has to be of a substantial diameter so that there is a risk that the wires will leave impressions on the glass. Also, as a substantial quantity of metal is present, a risk of thermal shock is involved.

Another known type of conveyor belt comprises metal slats joined side-by-side. This type of belt is, however, expensive and there is also a high risk of thermal shock.

GB Patent Application No. 9316122.2 filed on 4 August, 1993 discloses a conveyor belt which overcomes the abovementioned problems. This belt comprises a supporting layer having a thickness of lmm to 20mm, and a glass-engaging surface layer having a thickness up to lmm. The supporting layer is formed from fibres which are predominantly glass fibres. The glass-engaging layer is formed from a network of wires made from a heat-resistant metallic material.

Although the conveyor belt described in the abovementioned GB Patent Application is found to be satisfactory in many respects, in some circumstances, it is found that the containers are pushed off the belt when cooling air is directed on to them resulting in the containers breaking.

It is an object of the present invention to reduce the possibility of glassware containers being accidently pushed off conveyor belts of the type described in the abovementioned GB Patent Application, the invention also being applicable to other types of conveyor belts for hot glassware which have metallic glassware-engaging surfaces.

The invention provides a conveyor belt suitable for use in transporting hot glassware, the conveyor belt comprising a glassware-engaging layer made of heatresistant metallic material, at least part of said glassware-engaging layer having a coating thereon which is formed from particles of heat-resistant material adhered to the heat-resistant metallic material, the particles having dimensions up to 150 microns.

In a conveyor belt according to the invention, the coating is found to increase the co-efficient of friction between the glassware-engaging layer and the glassware so that there is less chance of the glassware being pushed off the belt. The coating is found not to significantly increase the risk of the glassware being marked.

The particles may suitably have dimensions in the range 5 to 45 microns.

The particles may be formed from the same heatresistant metallic material as the glassware-engaging layer, thereby avoiding a thermal expansion mismatch or any electrolytic effects. The particles may, however, be formed from another metallic material or a carbide. The particles may be of stainless steel. The particles may be applied by spraying, eg plasma or flame spraying.

The coating may only extend across a central region of the conveyor belt, ie not along the edges thereof. This enables the glassware to slide easily on to the conveyor belt until they reach said central region where the higher co-efficient of friction prevents them from easily sliding off.

Preferably, the glassware-engaging layer is formed by a network of wires. These wires may be knitted, braided, or woven into a sheet. In order to make the belt more flexible, in the case of a woven sheet, the weave thereof may extend at approximately 45 degrees to the direction of the belt. The pitch of such a sheet may be 200 to 4000 wires per meter, eg with 0.12mm diameter wire there may be 5 to 10 wires per cm ( a pitch of 500-1000). The wires may have a diameter of O.lmm to 0.5mum. The sheet may be in a flattened form, ie hammered or rolled flat to reduce the risk of marking the glassware, the hammering or rolling being performed before the coating is applied.

A conveyor belt according to the invention may also comprise a supporting layer having a thickness of lmm to 20mm, the glassware-engaging layer having a thickness of up to lmm and overlying the supporting layer and being secured thereto, the supporting layer being formed from fibres which are predominantly glass fibres. The supporting layer gives the belt sufficient strength that the glasswareengaging layer can be made sufficiently thin to avoid the dangers of thermal shock and with fine wires at a close spacing so that there is little danger of significant marking of the glassware. The glassware-engaging layer may be secured to the supporting layer by fasteners or stitches made of heat-resistant material, eg wire staples may be used.The glassware-engaging layer may be wrapped around the supporting layer and may contain abrasion-resistant fibres, eg of aramid, adjacent to the surface thereof which faces away from the glassware-engaging layer.

There now follow detailed descriptions, to be read with reference to the accompanying drawings, of four conveyor belts which are illustrative of the invention.

In the drawings: Figure 1 is a diagrammatic, perspective view of the first illustrative conveyor belt; Figure 2 is a cross-sectional view taken through the first illustrative conveyor belt; Figures 3 and 4 are views similar to Figure 2 but of the second and third illustrative conveyor belts, respectively; Figure 4 is similar to Figure 1 but shows the fourth illustrative conveyor belt; and Figure 5 is an cross-sectional view, on an enlarged scale, taken through a wire used to form a glasswareengaging layer of the any of the illustrative conveyor belts, showing the wire being coated with particles.

The first illustrative conveyor belt 10, the second illustrative conveyor belt 20, the third illustrative conveyor belt 30 and the fourth illustrative conveyor belt 40 are all suitable for use in transporting hot glassware.

Each of the illustrative conveyor belts comprises a supporting layer 12 which, in the case of the first belt 10 the second belt 20 and the fourth belt 40, are approximately 8mm in thickness and, in the case of the belt 30, is approximately lOmm in thickness. The supporting layer 12, in all four cases, is made from woven glass fibres.

The illustrative conveyor belts all comprise a glassware-engaging layer 14 which has a thickness of approximately 0.5mm and overlies the supporting layer 12 and is secured thereto. The surface layer 14 is, in all four cases, formed by a network of wires 16 made from stainless steel. These wires are approximately 0.25mm in diameter. In the drawings, in the interests of clarity, the wires 16 are shown much larger in diameter and further apart than they would be in reality.

In the belts 10, 20 and 30, the wires 16 are woven into a sheet which is then attached to the supporting layer 12. In the case of the belt 40, the sheet is knitted instead of woven from wires of 0.12 mm in diameter with about 8 wires per cm. In all cases, the sheet, prior to attachment, is rolled to flatten it to give it a smoother upper surface. The pitch of the woven sheet is approximately 2000 wires per metre so that during the rolling process, the wires can be crushed down into the spaces between them.

As shown in Figure 1, the weave of the sheet formed by the wires 16 of the belts 10, 20 and 30, extends at approximately 450 to the longitudinal direction 18 of the belt.

The wires 16 which form the glassware-engaging layers 14 of the illustrative conveyor belts 10, 20, 30 and 40 have a coating 42 thereon. The coating 42 is formed from particles 44 of heat-resistant material, specifically stainless steel. The particles (not shown in Figures 1 to 4) are adhered to the material of the wire 16. These particles 44 may have a dimension up to 150 microns, before they adhere to the wire, but preferably have dimensions in the range 5 to 45 microns.

The particles 44 are applied by plasma spraying and are introduced into the plasma and directed on to the wires 16 after the wires 16 have been formed into a sheet but before the sheet is secured to the supporting layer 12.

The particles 44 are directed against the surface of the sheet which will face away from the supporting layer 12, ie the surface on which the glassware will rest. The particles are only directed against a central portion of the sheet which forms a central portion of the layer 14 away from the wrapped over edges thereof. The arrow 46 in Figure 5 indicates the direction of travel of the particles 44 as they approach the wires.

The particles 44 arrive at the wires 16 in a molten condition and, on engaging them, flow across the surface of the wires and solidify thereon. The particles 44 splash on the surface and solidify into the coating 42 which is rough and predominantly on the upper surfaces of the wires 16.

The coating 42 is found to adhere strongly to the wires 16, although, if necessary, the wires can be beaded before coating to roughen its surface and increase adhesion.

The illustrative conveyor belts 10, 20 and 30 differ in the manner in which the glassware-supporting layer 14 is secured to the supporting layer 12. In the first illustrative conveyor belt 10, the longitudinal edges of the layer 14 are folded over the longitudinal edges of the layer 12 and staples 19, made of stainless steel, are inserted so that they pass through the layer 14 both above and below the layer 12. In the case of the conveyor belt 20, the layer 14 is wrapped completely around the layer 12 so that the layer 14 overlaps itself at 22. The overlapping portion is welded together to secure the layer 14 to the layer 12. In the case of the belt 30, the layer 12 has longitudinally-extending slots 24 in its longitudinal edges and the layer 14 has its longitudinal edges received in these slots 24.Staples 26, made of stainless steel, secure the edges of the layer 14 in the slots 24.

Since woven metal sheets are only obtainable in limited widths, the layer 14 of the belts 10, 20 and 30 has to be joined at intervals. These joins can be obtained by intermeshing the sheet with its neighbour and welding or brazing or sewing together, by overlying the sheet with its neighbour and welding, brazing or sewing together, or by folding over and adopting the same fastening measures. In all cases, the joint is rolled or hammered to be flat and co-planar with the remainder of the layer 14, prior to the application of the coating 42.

The knitted sheet of the fourth belt 40 is bent over the edges of the supporting layer 12 in similar manner to the sheet of the belt 20 and is secured to the supporting layer 12 by staples (not shown).

The illustrative conveyors belts 10, 20, 30 and 40 each have a glassware-engaging layer 14 which has a lower coefficient of friction in the edge regions thereof adjacent to the turned over edges thereof, and a central region which has a higher coefficient of friction. This arrangement enables glassware to slide easily on to the belt across an edge region thereof and be transported resting on the coating 42 with little likelihood of being pushed off the belt by air cooling jets.

Claims

CLAINS

1. A conveyor belt suitable for use in transporting hot glassware, the conveyor belt comprising a glasswareengaging layer made of heat-resistant metallic material, at least part of said glassware-engaging layer having a coating thereon which is formed from particles of heatresistant material adhered to the heat-resistant metallic material, the particles having dimensions up to 150 microns.

2. A conveyor belt according to claim 1, wherein the particles have dimensions in the range 5 to 45 microns.

3. A conveyor belt according to either one of claims 1 and 2, wherein the particles are formed from the same heatresistant metallic material as the glassware-engaging layer.

4. A conveyor belt according to claim 3, wherein the particles are stainless steel.

5. A conveyor belt according to any one of claims 1 to 4, wherein the particles have been applied to the glasswareengaging layer by plasma spraying or flame spraying.

6. A conveyor belt according to any one of claims 1 to 5, wherein the coating only extends across a central region of the belt.

7. A conveyor belt according to any one of claims 1 to 6, wherein the glassware-engaging layer is formed by a network of wires.

8. A conveyor belt according to claim 7, wherein the wires are knitted into a sheet.

9. A conveyor belt according to claim 7, wherein the wires are woven into a sheet.

10. A conveyor belt according to claim 9, wherein the glassware-engaging layer has its weave extending at approximately 45 degrees to the direction of the belt.

11. A conveyor belt according to any one of claims 8 to 10, wherein the glassware-engaging layer has a pitch of 200 to 4000 wires per meter.

12. A conveyor belt according to any one of claims 7 to 11, wherein the wires have a diameter of O.lmm to 0.5mm.

13. A conveyor belt according to any one of claims 8 to 12, wherein the sheet is in a flattened form.

14. A conveyor belt according to any one of claims 7 to 13, wherein the belt also comprises a supporting layer having a thickness of lmm to 20mm, the glassware-engaging layer having a thickness of up to lmm and overlying the supporting layer and being secured thereto, the supporting layer being formed from fibres which are predominantly glass fibres.

15. A conveyor belt according to claim 14, wherein the glassware-engaging layer is secured to the supporting layer by fasteners or stitches made of heat-resistant material.

16. A conveyor belt according to either one of claims 14 and 15, wherein the glassware-engaging layer is wrapped around the supporting layer.

17. A conveyor belt according to any one of claims 14 to 16, wherein the supporting layer contains abrasionresistant fibres.

18. A conveyor belt suitable for use in transporting hot glassware substantially as hereinbefore described with reference to, and as shown in, Figures 1 and 2, or Figure 3, or Figure 4, of the accompanying drawings.