GB2390072A

GB2390072A - Vacuum belt, encircles vacuum belt guide

Info

Publication number: GB2390072A
Application number: GB0202825A
Authority: GB
Inventors: Stephen Richard Ashton
Original assignee: Ashton Ind Sales Ltd
Current assignee: Ashton Ind Sales Ltd
Priority date: 2002-02-07
Filing date: 2002-02-07
Publication date: 2003-12-31
Also published as: GB0202825D0

Abstract

A vacuum belt apparatus, suitable for the transporting of glass sheets, comprises a continuous belt 1 with a plurality of perforations 4, driving means 2 and a belt guide 3 at least partially encircled by the belt 1. The belt guide 3 comprises a duct or manifold 14 with at least one upper surface aperture or bore 17, the duct 14 communicating with a vacuum pump 15. The belt may feature two rows of driving teeth 1. The driving means may comprise two drums 2. The belt apparatus may be used in combination with an arrising or edge smoothing or grinding apparatus, or multiple belts 1 may be combined with multiple arrising apparatus.

Description

IMPROVEMENTS IN AND RELATING TO BELT CONVEYORS

The field of the present invention relates to the transferring of sheet glass from one

location to another location, in particular as it applies to an arrissing line.

5 Background of the Invention

In order to manufacture toughened or tempered glass sheet and to prevent the glass shattering during the tempering process, the raw cut edges of each sheet of glass must be smoothed prior to the tempering process. This is accomplished by arrissing or grinding all the edges of each sheet. Machines for arrissing can comprise grinding wheels or two 10 or three continuous grinding belts coated or impregnated with, for example, silicone carbide or diamond grit. The belts in a two belt machine can be arranged to cross-over one another in an X configuration. Thus when a single edge of a glass sheet is offered to the belts at the cross-over point, the top and bottom of the edge is ground by the belts.

l he edge is arrissed by passing the full length of the edge across the grinding belts. Such 15 machines are known as cross-belt arrissing machines. A third belt can be orientated in an upright position for grinding the substantially perpendicular surface at the edge of the glass sheet.

On manually operated systems, each machine can only arriss one edge of a glass sheet at 20 any one time and in order to arriss more than one edge, the glass sheet must be rotated and each edge to be arrissed offered to the machine in turn. In high throughput arrissing lines for random size processing of rectangular glass sheets, each edge of a glass sheet is arrissed by a separate machine with a combination of roller and belt conveyors transporting each glass sheet between arrissing machines in such a manner that each edge 25 is offered to a different arrissing machine.

The arrissing machines are sited adjacent the conveyors which are used to offer the edges of the glass sheets for arrissing. Phe roller conveyors comprise a plurality of driven parallel rollers and retaining parapets located at opposing ends of the rollers which 30 transport the glass sheets past each arrissing machine. The rollers are orientated at an

acute angle to one parapet of the conveyor to impart a force component orthogonal to the direction of travel of the glass sheets. The glass sheets are hence forced towards a parapet ofthe conveyor adjacent the arrissing machines facilitating arrissing. Within the parapet walls are additionally provided freely rotating wheels, known as datum edge 5 guide wheels, the axes of which are substantially perpendicular to the plane described by the rollers, for facilitating easy movement of the glass sheets against the parapet walls.

The rollers directly adjacent to the grinding belts are shortened and the parapet removed in order to provide the belts with an unsupported edge to be arrissed.

10 The arrissing line described hereinbefore is poorly adapted to process small rectangular glass sheets as the grinding belts tend to push the lightweight glass sheets away on contact leading to uneven arrissing. Larger and heavier sheets do not suffer this drawback. More generally, the glass sheets, particularly those that are small and hence lightweight, can potentially slip on the conveyors under fast acceleration and 1 5 deceleration.

US 3 848 752 (Branch) discloses an apparatus for transferring glass sheets from a first location to a second location comprising a succession of rotatable driven rollers, and suction means arranged above the transfer path. The suction means are arranged to 20 operate so that suction is applied between the rollers to draw the sheets against the rollers.

The sheets are then advanced by the rollers while sectionally held against the lower surfaces of the rollers.

A disadvantage with the aforementioned apparatus is the continuous relative movement 25 between the surface of the rollers and the surface of the glass sheet which leads to damage to the surface of the glass sheet by dust and other detritus. l he problem is exacerbated when the glass sheet carries a soft surface coating.

Another method of transporting glass sheet is disclosed in DE 37 14 291 Al which 30 describes a continuous belt conveyor comprising a plurality of suction cups which are

: apparently able to retain glass sheet in fixed position on the belt.

Summary of the Invention

In a first embodiment of the invention, a vacuum belt apparatus for transporting sheet S glass comprising a continuous belt which is perforated by a plurality of perforations, driving means for driving the belt, a belt guide, at least partially encircled by the belt, for guiding the belt onto the driving means, the belt guide comprising a duct and at least one aperture in the upper surface of the duct, the duct communicating with a vacuum pump.

The driving means can comprise two drums, each one located at opposite ends ofthe belt 10 guide, at least one of which is driven by a motor.

Optionally the evacuation of air provided by the vacuum pump can be regulated by locating a valve between the duct and vacuum pump, or alternatively at the at least one aperture. One advantage of regulating the evacuation of air provided by the vacuum 1 S pump is to reduce the degree of evacuation permitting maneuvering of glass sheets on the belt. Each perforation can comprise a cylindrical bore. Alternatively they may comprise an elongate slot. Furthermore each perforation may terminate in an inverted frustro-conical 20 opening or alternatively at a opening with chamfered edges. One advantage with the latter design of perforation is the increase in working area under vacuum contacting the underside of each glass sheet. Furthermore such perforations are less likely to become clogged with dust, dirt, glass powder and water.

25 The belt can compri se at least one row of teeth protruding from the surface of the belt for engagement with the driving means for driving the belt. In particular the belt may comprise two rows of teeth. Each tooth can be of square, frustro-conical or triangular cross-section. 30 A second embodimcot of the invention comprises a method of transporthlg sheet glass

comprising the steps of evacuating the belt guide of the vacuum belt apparatus according to any one of the preceding claims; driving the belt; and feeding a sheet of glass onto the belt. Alternatively the method can comprise the steps of driving the belt of the vacuum belt apparatus according to any one of the preceding claims; evacuating the belt guide; 5 and feeding a sheet of glass onto the belt.

A third embodiment ofthe invention provides an arrissing line for sheet glass comprising at least one combination of an arrissing machine and a vacuum belt apparatus as hereinbefore described for conveying the sheet glass to, from and through the arrissing 10 machine, the vacunrn belt apparatus located adjacent the arrissing machine for firmly retaining the sheet glass in a fixed position relative to the belt during the arrissing process. In this way, moving glass sheet is retained at a fixed distance relative to the grinding belts. The arrissing line can be inside or outside track or a combination of inside and outside track. The arrissing line can include at least one roller conveyor for 15 transporting the sheet glass.

In an arrissing line comprising four arrissing machines and four vacuum belt apparatus in combination, the arrissing line may be laid out in one of the configurations selected from a G. an L, a U. an S or other configuration to suit site conditions. l he an arrissing 20 line may optionally comprise a vacuum belt apparatus for conveying sheet glass towards the arrissing machine, and a valve located between the duct and vacuum pump and/or at the at least one aperture, for regulating the evacuation of air provided by the vacuum pump, being actuable to reduce the evacuation of the vacuum pump whereby to permit sheet glass conveyed by the apparatus to be maneuvered or aligned prior to arrival at the 25 arrissing machine. Thus sheet glass which is not correctly aligned prior to arriving at the arrissing machine can be adjusted manually or by other means.

The arrissing line can comprise a second embodiment of vacuum belt apparatus which includes a belt guide with a duct comprising a closeended manifold and an elongate 30 block of substantially rectangular cross-section joined to the upper surface of the

s manifold and lying the length of the manifold overhanging the manifold on one side, the interior of the manifold communicating directly with the interior of the block, and the apparatus additionally comprising two pulleys located adjacent to the manifold and below the overhang ofthe block, the pulleys directing the portion ofthe belt passing underneath 5 the block back up towards the lower surface ofthe block, thereby relocating the belt away from the arrissing machine.

In a fourth embodiment of the invention, a method of arrissing or edge grinding sheet glass is provided comprising the steps of retaining a sheet glass on the belt of a vacuum 10 belt apparatus as described hereinabove; and offering the edge of the sheet glass to an arrissing machine.

Brief Description of the Drawings

Some embodiments of the invention will now be illustrated for the purposes of 15 exemplification by reference to the accompanying drawings, in which: Figure I is an exploded view of a first embodiment of vacuum belt apparatus; Figures 2a-2d are views of a second embodiment of vacuum belt apparatus, in which; Figure 2a is a cross-sectional view of a manifold and block; Figure 2b is an overhead view of the apparatus; 20 Figure 2c is a side view of the apparatus; Figure 2d is an end view of the apparatus; and Figure 3 is an overhead view of part of an arrisssing line comprising the second embodiment of vacuum belt apparatus.

25 Detailed Description of Embodiments

Figure I shows a first embodiment ofthe invention comprising a resilient continuous belt ( 1), driven by a rotating drum (2), the belt ( I) being guided onto the drum (2) by a belt guide (3).

30 The surface of the belt (1), prepared from a polyurethane elastomer reinforced with a

rubber-derived backing, is perforated by a plurality of perforations (4) arranged in a linear arrangement parallel to the direction of travel of the belt (1) as indicated by the large arrow.

5 Each perforation comprises a narrow bore (7) connecting a first surface (5) and a second surface (6) of the belt (1), terminating in an inverted frustro-conical or funnel-shaped opening (8) at the first surface (5).

Protruding from the second surface (6) of the belt (1) are two opposing parallel rows of 10 square teeth (9, 10) located on either edge of the belt ( 1) and parallel to the direction of travel of the belt (1) as indicated by the arrow. The two rows of teeth (9, 10) define a channel (1 1) into which the plurality of perforations open.

Rotating drum (2) is provided with a plurality of substantially equally spaced parallel 15 ridges (12) which lie on the periphery of the drum (2) substantially perpendicular and joined to two parallel circular end pieces (13). The cross-section of the ridges (12) is configured to permit the ridges (12) to engage the two rows of teeth (9, 10) on the belt (I). One of the two drums shown in Figure 1 is rotated by a drive belt (not shown) which is in turn connected to a motor spindle (not shown).

The belt guide (3) comprises a close-ended manifold (14) of rectangular cross-section connected directly to a vacuum pump ( 15). Joined to the upper surface of the manifold (14) is an elongate block (16) ol rectangular cross-section lying the length of the manifold. A plurality of belt guide bores (17) are located singly at regularly spaced 25 intervals along the length ofthe block (16) connecting the upper surface ofthe block (16) with the inside surface of the manifold (14). Each belt guide bore (17) opens into a chamfered rectangular recess (18) set into the upper surface ofthe block (16). The cross-

section of the block is adapted to be inserted into the channel (11) of the belt (1) permitting the two rows of teeth (9, 10) to be supported on the upper surface of the 30 manifold (14) either side of the block (16).

In use, when the vacuum pump (15) is engaged, each of the recesses (18) set into the upper surface of the block (16) are evacuated. A proportion of the recesses (18) will be in alignment with the perforations (4) and thereby firmly retain any sheet of glass placed flat on the belt under negative pressure. When the belt ( 1) is set in motion, a proportion 5 of the recesses (18) will always be in alignment with the perforations (4) at any one moment in time thereby maintaining the pressure preventing any sheet of glass placed flat on the belt (1) from sliding relative to the belt (1).

Figure 2a shows a second embodiment of the invention in which, when viewed in cross 10 section, the block (16) overhangs the manifold (14) on one side only. The block (16) is hollow and connects to the manifold (14), as shown in Figure 2a and 2b, through a single elongate slot (20). The upper surface of the block (16) is provided with a plurality of elongate apertures (21) orientated end to end and located in displaced arrangement with the slot (20).

Figures 2c and 2d illustrate the second embodiment in more detail and additionally shows two pulleys (22), located adjacent the manifold ( 14) and under the overhang of the block (16), which feed the portion of the belt (1) passing underneath the block (16) near the undersurface of the block (16). Ihe pulleys (2) thus enable the belt (1) to be driven 20 without that portion of the belt (1) passing underneath the block (16) impinging on one of the grinding belts (23) of a cross-belt arrissing machine. Such machines are used to grind the edges of glass sheets prior to their tempering. Arrissing prevents the glass shattering during the tempering process.

25 Figure 3 illustrates the vacuum belt apparatus ol the invention when used on an arrissing line in combination with rollers. in figure 3 a conventional cross-belt arrissing machine (30) is located adjacent a plurality of parallel rollers (3 1) which support and convey glass sheet. The rollers immediately adjacent the arrissing machine (30) are shortened to accommodate the vacuum belt of the present invention directly in front of the arrissing 30 machine (30).

In use the glass sheets are conveyed to the arrissing machine (30) on the rollers (31) which are driven by a motor (not shown) via a plurality of drive belts (not shown). In practice, the rollers (31) are not necessarily orientated perpendicular to the direction of travel of the glass sheets as shown in figure 3 but may desirably be orientated at an angle 5 such that they continually push each glass sheet towards the ends of the rollers nearest the arrissing machine (30). As glass sheet passes onto the belt ( I), the glass is retained firmly on the surface of the belt (1) by negative pressure and conveyed to the grinding belts (23) to be arrissed. The vacuum belt assembly is set sufficiently away from the arrissing machine (30) to permit the edge ofthe glass sheet to be arrissed to overhang the 10 belt (1).

In one embodiment evacuation is controlled by a valve (not shown) located between the manifold (14) and vacuum pump (15). In another embodiment, the pressure in each recess (18) is controlled by the provision of valves (not shown) located in each belt guide 15 bore (17).

Claims

Claims

1. A vacuum belt apparatus for transporting sheet glass comprising a continuous belt which is perforated by a plurality of perforations, driving means for driving the belt, a belt guide, at least partially 5 encircled by the belt, for guiding the belt onto the driving means, the belt guide comprising a duct and at least one aperture in the upper surface of the duct, the duct communicating with a vacuum pump.

2. A vacuum belt apparatus according to claim 1 wherein the driving 10 means comprise two drums, each one located at opposite ends of the belt guide, at least one of which is driven by a motor.

3. A vacuum belt apparatus according to claims 1 and 2 additionally comprising means to regulate the evacuation of air provided by the 1 S vacuum pump.

4. A vacuum belt apparatus according to claim 3 wherein the means to regulate the evacuation of air provided by the vacuum pump comprises a valve located between the duct and vacuum pump.

S. A vacuum belt apparatus according to claim 3 or claim 4 wherein the means to regulate the evacuation of air provided by the vacuum pump comprises a valve located at the at least one aperture.

25 6. A vacuum belt apparatus according to any one of the preceding claims wherein each perforation comprises a cylindrical bore.

7. A vacuum belt apparatus according to claim 6 wherein each perforation comprises terminates in an inverted frustro-conical opening.

X. A vacuum belt apparatus according to any one of claims 1 to 5 wherein each perforation comprises an elongate slot.

9. A vacuum belt apparatus according to claim 8 wherein each perforation 5 terminates at a opening with chamfered edges.

10. A vacuum belt apparatus according to any one of the preceding claims wherein the belt comprises at least one row of teeth protruding from the surface of the belt for engagement with the driving means for driving 10 the belt.

A vacuum belt apparatus according to claim 10 wherein the belt comprises two rows of teeth.

15 12. A vacuum belt apparatus according to claim 10 or claim 1 1 wherein the teeth are of square cross-section.

13. A vacuum belt apparatus according to claim 10 or claim I I wherein the teeth arc of frustro-conical cross-section.

14. A vacuum belt apparatus according to claim 10 or claim 1 I wherein the teeth are of triangular cross-section.

15. A method of transporting sheet glass comprising the steps of evacuating 25 the belt guide of the vacuum belt apparatus according to any one of the preceding claims; driving the belt; and feeding a sheet of glass onto the belt. 16. A method oftransporting sheet glass comprising the steps of driving the 30 belt of the vacuum belt apparatus according to any one of the preceding

claims; evacuating the belt guide; and feeding a sheet of glass onto the belt. 17. An arrissing line for sheet glass comprising at least one combination of 5 an arrissing machine and a vacuum belt apparatus according to any one of claims 1 to 14 for conveying the sheet glass to, from and through the arrissing machine, the vacuum belt apparatus located adjacent the arrissing machine for firmly retaining the sheet glass in a fixed position relative to the belt during the arrissing process.

18. An arrissing line according to claim 17 including at least one roller conveyor for transporting the sheet glass.

19. An arrissing line according to claim 17 or claim 18 comprising four 15 arrissing machines and four vacuum belt apparatus.

20. An arrissing line according to claim 19 wherein the arrissing line is laid out in one of the configurations selected from a G. an L, a U or an S configuration. 21. An arrissing line according to any one of claims 17 to 20 comprising a vacuum belt apparatus according to claim 4 or claim 5 for conveying sheet glass towards the arrissing machine, the valve being actuable to reduce the evacuation of the vacuum pump whereby to permit sheet 25 glass conveyed by the apparatus to be maneuvered or aligned prior to arrival at the arrissing machine.

22. An arrissing line according to any one of claims 17 to 21 wherein the vacuum belt apparatus includes a duct comprising a close-ended 30 manifold and an elongate block of substantially rectangular cross

section joined to the upper surface of the manifold and lying the length of the manifold overhanging the manifold on one side, the interior of the manifold communicating directly with the interior of the block, and the apparatus additionally comprising two pulleys located adjacent to 5 the manifold and below the overhang ofthe block, the pulleys directing the portion of the belt passing underneath the block back up towards the lower surface of the block, thereby relocating the belt away from the arrissing machine.

10 23. A method of arrissing or edge-grinding sheet glass comprising the steps of retaining a sheet glass on the belt of a vacuum belt apparatus according to any one of claims 1 to 14, and offering the edge of the sheet glass to an arrissing machine.

15 24. A vacuum belt apparatus substantially as described herein in accordance with the description and figures.

25. An arrissing line substantially as described herein in accordance with the description and figuecs.

26. A method of transporting sheet glass substantially as described herein in accordance with the description and figures.

27. A method of arrissing or edge-grinding sheet glass substantially as 25 described herein in accordance with the description and figures.