GB1590714A

GB1590714A - Apparatus for holding an article against a conveyor

Info

Publication number: GB1590714A
Application number: GB405078A
Authority: GB
Original assignee: ROUSE GLASS MACHINERY Ltd JOHN
Current assignee: ROUSE GLASS MACHINERY Ltd JOHN
Priority date: 1978-05-30
Filing date: 1978-05-30
Publication date: 1981-06-10

Description

(54) APPARATUS FOR HOLDING AN ARTICLE AGAINST A CONVEYOR (71) We, JOHN ROUSE (GLASS MACHINERY) LIMITED, a British Company, of Butlers Leap, Clifton Road, Rugby, Warwickshire, 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: The invention relates to apparatus for holding an article against a conveyor and is particularly, but not exclusively, concerned with apparatus for holding glass-sheet against a conveyor which moves the sheet through an edge grinding machine.

Glass sheet edge grinding machines normally support the glass-sheet on conveyor means either horizontally or slightly out of the vertical to enable its edges to be ground. Where the sheet is supported horizontally, it normally rests on a belt conveyor which carries it through the machine. In order to ensure that the sheet is held firmly against the conveyor to prevent yawing, two rows of spring-loaded rollers normally engage the upper surface of the sheet adjacent the edges to be ground. As the sheet is conveyed through the machine, the leading edge engages the rollers in succession which subsequently ride up onto the sheet.

Certain drawbacks arise when using such rollers.

Firstly, the spacing of the rollers in each row is usually such that only sheets above a certain minimum length can be machined. Whilst this is not important when the user is grinding sheets above that size, the machine is useless when the user wants to grind smaller sheets. Of course, additional rollers could be added to help overcome this problem but they would add significantly to the cost of the machine.

Secondly, the bearings of the rollers are prone to rapid wear as they are under load continuously. Thirdly, it is difficult to ensure even spring loading of the rollers throughout. Therefore, if the leading edge of the sheet simultaneously engages corresponding rollers in each row which are not evenly loaded, the sheet will sometimes yaw: In a vertical sheet edging machine, the sheet has to be clamped against the conveyor to prevent it from slipping downwards. In order to clamp the sheet, the conveyor normally comprises a chain.iike track which carries a large number of spring-loaded jaws for clamping the glass. Such conveyors are very expensive mainly due to the complexity of each jaw and the length of time it takes to assemble.

An object of the present invention is to provide apparatus in which at least some of the foregoing disadvantages are less likely to occur.

According to one aspect of the invention, there is provided apparatus for holding an article against a conveyor comprising a member having a surface movable towards the conveyor, support means adajcent the conveyor for said member, and an inflatable envelope arranged in a space defined between the member and the support means so that inflation of the envelope by fluid under pressure urges the member towards the conveyor relative to the support means to hold the article against the conveyor.

The member preferably includes an inflatable tube which extends longitudinally of the conveyor. The support means may be in the the form of an elongate member which slidably supports a plurality of closely adjacent members through which said inflatable tube exerts the said force for holding the article against the conveyor. With such an arrangement, inflation of the tube causes the elements to move relatively to the elongate member towards the conveyor. Each element may be in the form of a housing, each housing defining a passageway so that the housings together define a single elongate passage formed from the individual passageways and which houses the elongate member, the passageway being dimensioned so that a portion thereof forms the space through which the elongate tube extends. Each housing may be formed with a recess in an edge adjacent the conveyor, the recesses together forming a single elongate recess which guides an endless belt for holding the article against the conveyor when the tube is inflated.

The elongate member may be channel shaped in cross-section and, in such a case, each of the elements may comprise a block which fits inside the channel, said inflatable tube being disposed between the inside surface of the channel and the block so that inflation of the tube moves each block towards the mouth of the channel. Preferably, each said block is formed with a recess in a surface remote from the tube, the recess in the blocks together forming a single elongate recess which guides an endless belt for holding the article against the conveyor.

According to another aspect of the invention, there is provided an edging machine for a flat workpiece including two parallel conveyors, and two sets of apparatus for holding the workpiece against the respective conveyors to enable opposite edges of the workpiece to be machined, each set of apparatus comprising a member disposed adjacent its associated conveyor which has a surface movable toward that conveyor, support means adjacent that conveyor for the member and an inflatable envelope arranged in a space between the member and the support means so that inflation of the envelope by fluid under pressure urges the member towards the conveyor relative to the suppprt means to hold the article against the conveyor.

Means may be provided for orientating the workpiece with respect to the direction of movement of the conveyors. Said means preferably comprises an arm adjacent each conveyor which moves into the path of the workpiece on the conveyor and engages its leading edge. A trigger device operable by the workpiece may be provided for moving the arms into and out of the path of the workpiece. A further device may be provided which prevents the arms from moving until the trailing edge of the workpiece has moved to a position beyond the path of the arms. Preferably, each arm has an adjustable workpiece engaging stop thereon.

Apparatus in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which Figure 1 is a schematic elevation of part of a machine incorporating apparatus in accordance with the invention Figure 2 is an end elevation of the part of the machine shown in Figure 1; Figure 3 is a cross-section through a supporting bar showing one type of tube housing in detail; Figure 4 is a perspective view showing a squaring device on a machine similar to that in Figure 1, the machine being shown partly broken away; Figure 5 is a view similar to Figure 3 but illustrating a different type of tube housing; Figure 6 is an elevation showing how housings can be arranged at spaced apart positions on the supporting bar; and Figure 7 is a cross section through apparatus in accordance with the invention for use in a vertical glass sheet edging machine.

Referring firstly to Figures 1 to 4, a machine, such as a glass-sheet edging machine, includes two parallel conveyors 10 for moving a sheet of material 2 through the machine. Each conveyor is preferably of the endless belt type driven by a motor powered roller 12, the belt being tensioned by an adjustable roller 13. Each belt is supported between the rollers by means indicated at 14.

Directly above each conveyor 10 is arranged a supporting bar 15 on which is slidably mouth ted a plurality of housings 16 shown in greater.

detail in Figure 3. Each bar 1.5 is parallel withy its associated conveyor 10. Each housing comet prises sides 17 and ends 18, the lattet being re- cessed at 19 to receive an endless belt 20. The housing 16 is formed with a rectangular aperture 22 which slidably receives the bar 15. As shown in Figure 3, a space is defined between the underside of the bar 15 and the lower end 18 of the housing. When the housings are in position on the bar as shown in Figures 1 and 4, the aforesaid spaces align to define an elon- gate passage which houses a gas-tight tube 23 of flexible material. The tube is connected. to a source of fluid P such as compressed air. The belt 20 passes around rollers 21 which may be; rotatably mounted on plates 15a secured to the bar 15 or otherwise suitably supported.

The belt 20 is driven at the same peripheral speed as the conveyor belt .10 and the lower run of belt 20 moves in the same; direction as the upper run of the conveyor belt 10. The belts 10, 20 are preferably of the toothed kind.

The belts 20 are guided by plates 26 over their end rollers.

When each tube 23 is in a deflated-con- dition, the lower runs of belts 20 rest lightly on the conveyor belts'l0. When cornpressed air is introduced in each tube 23, the tubes in flate and urge the lower runs of belts 20 into firm engagement with the conveyors 10. When a sheet of glass or other material is fed on to the parallel conveyors 10 (which are moving at equal speeds) it is gripped between the belts 20 and the conveyors 10 (with.the tubes 23 in flated) and the successive housings 16. ride up on to the top of the sheet -2 as it moves towards the right as viewed in Figure 1. -As the trailing edge of the sheet moves to the right of the extreme left-hand housing on each bar-IS, that housing moves downwardly and is followed by the subsequent housings as they clear.the-trail- ing edge. As shown in Figure 2, the source of pressure P may be common to both tubes 23.

In this manner, equal pressure is applied to both tubes 23 and, therefore, an equal load isoapplied to each edge of the sheet 2. This helps to prevent yawning of the sheet 2 as it travels through the machine. However it is possible for a sheet of glass to be fed into the machine so that its straight leading edge is not exactly aright angles to the direction of travel. . This is particularly the case where a long, narrow sheet of glass (such as that indicated at .2a in Figure 4) is fed through the machine so that its ends can be ground. To ensure that the leadingkedge of the sheet is correctly orientated, two arms 30 are arranged slightly in board of each conveyor 10. The arms 30 are identical and are slidably mounted on a rotatable square cross-section bar 31. The bar 31 is rotatable through an angle 0 by a double acting ram 32 fed with fluid via first and second solenoid valves (not shown).

When the glass sheet 2a is just nipped between the belts 10, 20 the leading edge actuates the first solenoid valve and causes the arms 30 to move through angle 0 into the positions shown.

Stop faces 33 on the arms 30 engage the leading edge of the sheet 2a as it continues to move and causes the sheet to yaw and move into the correct orientation if its leading edge is skewed.

The stop faces 33 may comprise adjustable stops. The leading edge then actuates the second solenoid valve which moves the arms 30 clear of the glass. Once the sheet has been squared by the arms 30 it then passes fully beneath the housings 16 so that its ends can be ground. The right hand arm 30 as viewed in Figure 4 is rotatably mounted in a bearing 32 carried by the adjacent conveyor support means 14. The right hand set of conveyors is movable towards or away from the other set and on doing so the right hand arm 30 slides along the bar 31. If the two sets of conveyors are adjusted so that they lie close together, the left hand arm can be pushed along the bar 31 by the right hand arm into a clearance space (not shown) between the upper and lower runs of the left hand conveyor belt 10. The arms 30 will not operate in that condition but this is usually unimportant when grinding very short pieces of glass. A spring 33 returns the left hand arm 30 into its original position when the left and right hand conveyors are moved sufficiently apart once more. A device (not shown) may be provided for preventing the arms 30 moving upwardly until the trailing edge of the sheet is well clear of their lines of travel. In that way,the arms 30 would not be triggered by a second sheet fed into the machine before the trailing edge of the previous sheet had cleared the arms 30.

In order to reduce friction between the sides 17 of the housings and the tube 23, the bar 15 may be provided with side plates 24 as shown in Figure 5.

In Figures 1 and 4, adjacent housings on each bar 15 touch each other. However, it is envisaged that the housings may be mounted in a spaced configuration as shown in Figure 6 where pegs 25 on the bar 15 locate in vertical slots 26 in the housings.

The apparatus of the invention is particularly well suited for use in a glass sheet edging machine as the edges to be ground will be held firmly and there is little likelihood of the sheet yawing. Also, the length of the sheet which can be ground is considerably less than that which can be ground on a machine of similar size which uses spring loaded rollers to hold the sheet down.

The load applied to the sheet 2 by the belts 20 can easily be increased by increasing the pressure of source P.

When using the apparatus of the invention in a vertical glass sheet edging machine the belt 20 will extend horizontally with its periphery inclined slightly to the vertical. In such a case, the pressure in tube 23 will be increased to provide a grip between the conveyor and associated belt 20 sufficient to prevent the sheet slipping downwards. Figure 7 shows an arrangement particularly suitable for vertical glass sheet edging machines. Two channel cross-section members 40 slidably support a plurality of blocks 41 equivalent to the housings 16 of Figures 1 to 4. The blocks 41 are recessed to receive inner runs 42 of endless belts 43 the outer runs 44 of which pass alongside the members 40.

The belts 43 pass around pulleys (not shown) at their ends which transmit drive to the belts.

Each member 40 contains an air bag 45 which extends behind all adjacent blocks 41. Admission of compressed air to the bags 45 urges the blocks 41 and inner runs 42 towards each other. In use, a glass sheet 46 is gripped between the inner runs 42 and is carried through the machine by the belts 43. It is envisaged that the grip on the sheet 46 effected by the belts 43 will be sufficient to prevent the sheet slipping downwards under the force of gravity.

Sheets of various thicknesses may be gripped between the belts 43 and it is envisaged that if equal pressures are fed to tubes 45, the blocks 41 will move equal distances within their respective members 40 so that the centre line C of all sheets will remain fixed. This is particularly useful as it reduces the need to make grinding wheel adjustments when sheets of various thicknesses are being ground in succession. Two such arrangements as shown in Figure 7 would normally be used on the vertical glass sheet edging machine positioned one adjacent each edge to be machined.

Whilst the apparatus is particularly applicable to glass sheet edging machines, it may be used in machines which edge sheets of timber or metal, or in other machines where an article is to be held against a conveyor.

WHAT WE CLAIM IS: 1. Apparatus for holding an article against a conveyor comprising a member having a surface movable towards the conveyor, support means adjacent the conveyor for said member, and an inflatable envelope arranged in a space defined between the member and the support means so that inflation of the envelope by fluid under pressure urges the member towards the conveyor relative to the support means to hold the article against the conveyor.

2. Apparatus according to Claim 1, in which the envelope is an elongate tube which, in use, extends through said space longitudinally of the conveyor.

3. Apparatus according to Claim 2, in which the support means is an elongate member which slidably supports a plurality of closely adjacent members through which said inflatable tube exerts the said force for holding the article against the conveyor.

4. Apparatus according to Claim 3, in which

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. by a double acting ram 32 fed with fluid via first and second solenoid valves (not shown). When the glass sheet 2a is just nipped between the belts 10, 20 the leading edge actuates the first solenoid valve and causes the arms 30 to move through angle 0 into the positions shown. Stop faces 33 on the arms 30 engage the leading edge of the sheet 2a as it continues to move and causes the sheet to yaw and move into the correct orientation if its leading edge is skewed. The stop faces 33 may comprise adjustable stops. The leading edge then actuates the second solenoid valve which moves the arms 30 clear of the glass. Once the sheet has been squared by the arms 30 it then passes fully beneath the housings 16 so that its ends can be ground. The right hand arm 30 as viewed in Figure 4 is rotatably mounted in a bearing 32 carried by the adjacent conveyor support means 14. The right hand set of conveyors is movable towards or away from the other set and on doing so the right hand arm 30 slides along the bar 31. If the two sets of conveyors are adjusted so that they lie close together, the left hand arm can be pushed along the bar 31 by the right hand arm into a clearance space (not shown) between the upper and lower runs of the left hand conveyor belt 10. The arms 30 will not operate in that condition but this is usually unimportant when grinding very short pieces of glass. A spring 33 returns the left hand arm 30 into its original position when the left and right hand conveyors are moved sufficiently apart once more. A device (not shown) may be provided for preventing the arms 30 moving upwardly until the trailing edge of the sheet is well clear of their lines of travel. In that way,the arms 30 would not be triggered by a second sheet fed into the machine before the trailing edge of the previous sheet had cleared the arms 30. In order to reduce friction between the sides 17 of the housings and the tube 23, the bar 15 may be provided with side plates 24 as shown in Figure 5. In Figures 1 and 4, adjacent housings on each bar 15 touch each other. However, it is envisaged that the housings may be mounted in a spaced configuration as shown in Figure 6 where pegs 25 on the bar 15 locate in vertical slots 26 in the housings. The apparatus of the invention is particularly well suited for use in a glass sheet edging machine as the edges to be ground will be held firmly and there is little likelihood of the sheet yawing. Also, the length of the sheet which can be ground is considerably less than that which can be ground on a machine of similar size which uses spring loaded rollers to hold the sheet down. The load applied to the sheet 2 by the belts 20 can easily be increased by increasing the pressure of source P. When using the apparatus of the invention in a vertical glass sheet edging machine the belt 20 will extend horizontally with its periphery inclined slightly to the vertical. In such a case, the pressure in tube 23 will be increased to provide a grip between the conveyor and associated belt 20 sufficient to prevent the sheet slipping downwards. Figure 7 shows an arrangement particularly suitable for vertical glass sheet edging machines. Two channel cross-section members 40 slidably support a plurality of blocks 41 equivalent to the housings 16 of Figures 1 to 4. The blocks 41 are recessed to receive inner runs 42 of endless belts 43 the outer runs 44 of which pass alongside the members 40. The belts 43 pass around pulleys (not shown) at their ends which transmit drive to the belts. Each member 40 contains an air bag 45 which extends behind all adjacent blocks 41. Admission of compressed air to the bags 45 urges the blocks 41 and inner runs 42 towards each other. In use, a glass sheet 46 is gripped between the inner runs 42 and is carried through the machine by the belts 43. It is envisaged that the grip on the sheet 46 effected by the belts 43 will be sufficient to prevent the sheet slipping downwards under the force of gravity. Sheets of various thicknesses may be gripped between the belts 43 and it is envisaged that if equal pressures are fed to tubes 45, the blocks 41 will move equal distances within their respective members 40 so that the centre line C of all sheets will remain fixed. This is particularly useful as it reduces the need to make grinding wheel adjustments when sheets of various thicknesses are being ground in succession. Two such arrangements as shown in Figure 7 would normally be used on the vertical glass sheet edging machine positioned one adjacent each edge to be machined. Whilst the apparatus is particularly applicable to glass sheet edging machines, it may be used in machines which edge sheets of timber or metal, or in other machines where an article is to be held against a conveyor. WHAT WE CLAIM IS:

1. Apparatus for holding an article against a conveyor comprising a member having a surface movable towards the conveyor, support means adjacent the conveyor for said member, and an inflatable envelope arranged in a space defined between the member and the support means so that inflation of the envelope by fluid under pressure urges the member towards the conveyor relative to the support means to hold the article against the conveyor.

4. Apparatus according to Claim 3, in which

each member is in the form of a housing, each housing defining a passageway so that the housings together define a single elongate passage formed from the individual passageways and which houses the elongate member, the passageway being dimensioned so that a portion thereof forms the space through which the elongate tube extends.

5. Apparatus according to Claim 4, in which each housing is formed with a recess in an edge adjacent the conveyor, the recesses together forming a single elongate recess which guides an endless belt for holding the article against the conveyor when the tube is inflated.

6. Apparatus according to Claim 3, in which the elongate member is channel shaped in cross-section and each of the members comprises a block which fits inside the channel, said inflatable tube being disposed between the inside surface of the channel and the block so that inflation of the tube moves each block towards the mouth of the channel.

7. Apparatus according to Claim 6, in which each said block is formed with a recess in a surface remote from the tube, the recess in the blocks together forming a single elongate recess which guides an endless belt for holding the article against the conveyor.

8. Apparatus according to any of Claims 1 to 5, in which the housings are held spaced apart along the elongate member by means of pegs on said elongate member which locate in slots in the housings.

9. An edging machine for a flat workpiece including two parallel conveyors, and two sets of apparatus for holding the workpiece against the respective conveyors to enable opposite edges of the workpiece to be machines, each set of apparatus comprising a member disposed adjacent its associated conveyor which has a surface movable towards that conveyor, support means adjacent that conveyor for the member, and an inflatable envelope arranged in a space between the member and the support means so that inflation of the envelope by fluid under pressure urges the member towards the conveyor relative to the support means to hold the article against the conveyor.

10. An edging machine according to Claim 9, in which each envelope is an elongate tube which extends longitudinally of the associated conveyor.

11. An edging machine according to Claim 10, in which each support means is an elongate member which slidably supports a plurality of closely adjacent members through which said inflatable tube exerts the said force for holding the article against the associated conveyor.

12. An edging machine according to Claim 11 , in which each member is in the form of a housing defining a passageway so that the housings on each elongate member together define a singe elongate passage formed from the individual passage ways and which houses the elongate member, the passageway being dimensioned so that a portion thereof forms the space through which the elongate tube extends.

13. An edging machine according to Claim 12, in which each housing is formed with a recess in an edge adjacent the associated conveyor: the recesses together forming a single elongate recess which guides an endless belt for holding the article against that conveyor when the tue is inflated.

14. An edging machine according to any of Claims 9 to 13, in which each conveyor is in the form of an endless conveyor belt.

15. An edging machine according to any of Claims 9 to 14, in which means is provided for orientating the workpiece with respect to the direction of movement of the conveyors.

16. An edging machine according to Claim 15, in which said means comprises an arm adjacent each conveyor which moves into the path of the workpiece on the conveyor and engages its leading edge.

17. An edging machine according to Claim 16, in which a trigger device operable by the workpiece is provided for moving the arms into and out of the path of the workpiece.

18. An edging machine according to Claim 16 or Claim 17, in which a further device is provided which prevents the arms from moving until the trailing edge of the workpiece has moved to a position beyond the path of the arms.

19. An edging machine according to any of Claims 16, 17 or 18, in which each arm has an adjustable workpiece engaging stop thereon.

20. An edging machine according to Claim 11, in which each elongate member is channel shaped in cross-section and each of the members comprises a block which fits inside the channel, the associated inflatable tube being disposed between the inside surface of the channel and the associated blocks so that inflation of the tube moves the blocks towards the mouth of the channel.

21. An edging machine according to Claim 20, in which the conveyors and the apparatus for holding the workpiece against the conveyors are mirror images of each other.

22. An edging machine according to any of Claims 9 to 21, in which equal fluid pressure is applied to the members which hold the workpiece against the conveyor.

23. Apparatus for holding an article against a conveyor constructed and arranged substantially as described herein with reference to and as illustrated in Figures 1 to 4, Figure 5, Figure 6 or Figure 7 of the accompanying drawings.