NO136745B - - Google Patents

Description

The present invention relates to the transport or moving of plate material, e.g. glass sheets from a first location to another location, for example in connection with the stacking of sheets, which are carried one after the other along a conveyor belt to a stacking location, or to remove the sheets one by one from the stack and transfer these sheets to a conveyor belt that carries them for further processing, using a separate release or release chamber enclosed in a suction hood used for transfer of the sheet material by means of suction exerted from the suction hood.

In US patent 3,272,351 a device for processing plywood sheets is discussed and in which fig. 2 shows a plywood sheet which is split along the middle by means of a saw 4 and fed forward on a series of belts 2. The two sheets are fed into a stacking device comprising two vacuum conveyors 5 and 6 which are long, narrow structures mounted above the path of the plates and parallel to the belts 2. One of these vacuum conveyors is illustrated in fig. 3, 4 and 5 and each comprises a vacuum chamber where belts 51 run along the lower edges of the chamber. These belts act to drive the plate as it is sucked into sealing engagement with these belts (see column 7, lines 61 - 64). The only air-

current that can take place takes place through the veneer sheet itself, which is porous.

Each of these vacuum conveyors has the form of a long slot which extends in the direction of advance for the veneer sheets with sealing belts at the sides of the slots as the veneer sheets are drawn towards the slots by suction. Inside the elongated slot between the belts there is a complicated valve system with rotary valves to seal the slot when some veneer is not being transported. The valves are opened in sequence at the leading edge of the veneer sheet to allow the suction to be applied. This is best illustrated in fig. 7.

Figs. 4 and 5 show a switch lever 41 connected to a switch 40. The negative pressure affects a release flap valve 30 shown in fig. 5 and which normally closes the left side of the vacuum chamber. The flap valves at the two vacuum conveyors are mounted on a common shaft so that they work together when a veneer sheet is in the stacking position.

When a veneer sheet is to be dropped, the negative pressure over the full length of the conveyor is broken by opening the valves 30. There is no special or separate release chamber above the stacking position as in the present invention.

US patent document 3,272,351 also does not show driven rollers that protrude from the underside of the suction cap so that a limited air flow is allowed over the plate being transported. This is particularly important when transporting non-porous glass sheets,

in contrast to the device known from the aforementioned patent document, in that the porosity in the plates cannot be utilized so that the edges of the plate can be kept in sealing engagement with the belts.

The feature with protruding rollers is known in and of itself from US patent document 3,391,926 where in fig. 2 shows rollers 9 that stick out somewhat from the underside of a suction cap 5.

It is a main purpose of this invention to provide an improved apparatus for transferring sheet material by a suction arrangement, in which sheets are lifted and transferred by means of suction exerted on the upper side of the sheets.

The invention thus relates to an apparatus for transferring plate material, in particular glass plates, from a first location to another location, comprising a suction hood with an open bottom and extending along a transfer path between the said locations, a series of drive rollers arranged in the open bottom of the suction hood so that they come into contact with the upper side of a plate which is sucked against the drive rollers by means of a negative pressure in the suction cap, so that the plate is thereby carried forward along the transfer path, as well as devices which are affected by the plate's movement to reduce the suction in the suction cap to release a plate from the rollers, and the peculiarity of the apparatus according to the invention is that it comprises a separate release chamber delimited in the suction cap adjacent to the other place with devices in connection with the release chamber to reduce or interrupt the suction therein.

It is preferred that the drive rollers are mounted across the transport path. The drive rollers can be cylindrical rollers or can be rollers provided with segments of increased diameter, and these segments are placed at a distance from each other so that a plate being transferred is in contact with at least two of these segments on each roller.

The suction device consists of a suction hood where several drive rollers are framed at the bottom, the hood having an open bottom through which the drive rollers protrude somewhat.

The drive rollers can be cylindrical rollers mounted close to them

the outer drive rollers abutting the end walls of the suction hood, the limited openings between adjacent rollers and between the outer drive rollers and the end walls of the hood creating a throttling device that prevents an undesired large air flow when there is no plate present under the drive rollers.

In this embodiment where the drive rollers are mounted in the bottom of a suction hood, a perforated air choke plate can be mounted across the cap above the rollers and several flexible flaps hang down from the choke plate towards the drive rollers to close off the spaces between adjacent drive rollers from each other, the choke plate is provided with openings which are connected to each closed space. The suction hood is then divided into several suction chambers each connected to one of the drive rollers and each suction chamber is connected to a normal suction chamber which is found on the other side of the throttle plate in the suction hood.

Usually plates, e.g. sheets of glass, carried forward in sequence on a conveyor belt and arriving at the first place in sequence and where there are lifting devices operative to

lift the plate so that it is gripped by the drive elements.

When the drive elements have transferred the plate to the other location, e.g. where it is to be stacked, the suction is interrupted so that the plate can be released from the drive elements and in one device there are suction control devices which are operative to interrupt the suction when a plate has been transferred to another place so that the plate falls from the drive elements at this other place.

Some embodiments may include release devices arranged to be released upon movement of a plate to the second location, and valve means controlled by the release devices for interrupting suction in at least a portion of the suction cap so that the plate may be released when it reaches the second place. It is preferred that the release devices comprise a switch device which is placed in the path of the plate and valve devices consisting of a damping part placed in a hole which connects the cap to a suction channel.

An alternative is an air passage device with low resistance placed next to a drive roller at the beginning of the path through the suction cap, so that the suction is applied when a plate forms a bridge over the said air passage device next to the said roller, but is released when the trailing edge of the plate passes the aforementioned roller, thereby depositing the plate at the second location. It is preferred that a selective active device is acquired to limit the aforementioned air passage device when a plate is to be passed past the second location without releasing the plate at the second location. It can be arranged so that the said roller in the suction hood consists of two discs placed at a distance from each other and with an adjustable damper part between them, the damper part being adjustable to change the throttling of the air flow between the disc parts. An alternative is that the distance between said one roller and the next roller in the suction hood is significantly greater than the distance between other rollers in the hood and that an adjustable damper part is placed in this large space.

In order for the rollers to release one plate while suction is maintained for another plate, a plate can be fitted across the cap above the rollers, suction paths which are positioned at a distance from the chamber below the plate and shut-off devices which can be placed between a selected roller and the plate between the mentioned suction paths so that they divide the suction chamber under the plate and prevent the suction from being interrupted in one part of the chamber when the suction is interrupted in another part of the chamber. The shut-off devices may consist of several rotatable flaps, each of which is placed above a roller and selectively movable to close the space between the rollers and the plate, the flap being moved to the closed position is chosen so that the part of the chamber, in which the suction is released, has a length which depends on the length of the plate being moved. Alternatively, the shut-off devices consist of a sliding shut-off part placed between the top of the rollers and said plate and adjustable in position along the row of the roller.

At least the last roller at the second location may be arranged for vertical movement to a height below the other drive rollers, release devices, e.g. a limit switch, is arranged to be triggered by a plant being moved towards the second location and starts the lowering of the last driving roller so that the plate is deposited at the second location.

At the second location, reception devices can be placed,

on which the plates fall, and these receiving means are arranged in a support which can be raised to receive a plate detached from the drive elements and lowered to lower the plate to a desired level so that the plate can be stored.

In the case of an expansion of the apparatus, there can be several stacking locations over which the drive elements extend, apparatus units that include release devices at each placement location selectively active to build up more stacks at the stacking locations based on selective plate size.

The invention can also be used when removing plates from a stack, which is raised in stages as the plates are pulled from the top of the stack, by raising them close to the drive rollers before the suction is applied, to pull each plate in turn towards the drive rollers which thereby move the plates away from the top of the stack towards another location.

In order to make the invention more clearly understood, some embodiments of this will now be described by means of examples, with reference to the attached drawings, where the device according to the invention is shown in connection with different embodiments of transmission equipment. Fig. 1 is a side view of an embodiment of an apparatus for transferring glass sheets from a first transport device to a second transport device.

Fig. 2 is a front view of the apparatus in fig. 1.

Fig. 3 shows the suction devices in the apparatus shown in figures 1 and 2 seen from the underside. Fig. 4 shows in a similar way as in fig. 3 a modification of the apparatus in fig. 1 to 3. Fig. 5 is a side view, partly in section, of another embodiment of an apparatus for transferring glass sheets from one transport device to another transport device.

Fig. 6 is a front view of the apparatus in fig. 5.

Fig. 7 is a cross-section of a side rip saw, another apparatus for transferring glass sheets. Fig. 8 is a side view, partly in section, of yet another apparatus for transferring glass plates. Fig. 9 shows the use of an embodiment of the suction device for transferring glass sheets to a stacking location.

Fig. 10 shows the device in fig. 9 seen from above.

Fig. 11 shows the corresponding fig. 9 another apparatus for transferring glass sheets to a stacking location. Fig. 12 is a side view showing another embodiment of an apparatus used for selective stacking of plates at several stacking locations. Fig. 13 is a side view of part of another embodiment of the apparatus used with a stacking arrangement as shown in fig. 12.

Fig. 14 is a half plan view of part of the embodiment shown in fig.

13 seen from above.

Fig. 15 is a schematic representation of the control devices used in the embodiment shown in fig. 13 and 14. Fig. 16 is a side view of a further embodiment of the apparatus for use when stacking glass sheets. Fig. 17 is a side view of yet another embodiment of the apparatus for use when stacking glass plates.

Fig. 18 is a perspective view of part of the apparatus shown in fig.

17, and

Fig. 19 shows an alternative construction for the part of the apparatus shown in fig. 17.

In the drawings, the same designations will indicate the same or corresponding parts.

With reference to fig. 1 and 2 there is shown a transport device for glass plates consisting of a series of rotatable rollers which are operated in a known manner and by known devices the glass plates, supported thereon, are conveyed horizontally to a transfer point, generally indicated at 2. The last rollers 1 form a first place from where the glass sheets are to be transferred to another location formed by the first rollers indicated at 14 on another transport device. The transport rollers 1 and 14 are supported by a base 13. The rollers 14

is also driven to transport a plate, once it has been moved to the rollers, rapidly away from the transfer point. A vertically adjustable stacking table or similar can be placed under the transfer point 2 so that the glass sheets, when desired, can be transferred from the transport rollers 1 to the stack or taken away from

the stack and moved to the transport rollers 14.

At the transfer point, a series of driven horizontal rollers 3 are mounted in bearings which hang down from a beam 4 so that the underside of the rollers 3 is separated along and above the path for the movement of the glass sheets. All the rollers 1, 3 and 14 can be of a known shape, usually they are cylindrical and have protruding rings of suitable material placed at intervals, e.g. rubber that grips the glass plates being fed. The peripheries of the rollers in contact with the glass plates are thus the periphery of the protruding rings. However, the rollers can be of the usual cylindrical shape.

At the transfer point in the space between each pair of successive drive rollers 3 is a suction chamber 5 whose lower end is shaped as shown in fig. 1 to fit closely but not to be in contact with the periphery of the rollers 3. The lower end of each suction chamber has a flared hood-like shape as shown in fig. 2. Each suction chamber has a bottom wall formed by horizontal plates 6, shown in fig. 3 with holes 7. The underside of each plate is at a height slightly above, e.g. 1.2 mm above the height of the lowest point of the peripheries of the rollers 3. The suction chambers 5 are connected through respective channels 8 to a common suction manifold connected by a channel 10 to a fan unit, which is not shown.

The rollers 3 are made to rotate in the usual way. E.g. there can be a chain connection between the rollers 3 and the rollers have suitable chain drives 11, fig. 2, to provide a common drive connection,

while one of the rollers has a protruding drive shaft which carries a drive device 12. The beam 4 is supported from the base 13 by means of struts which have been omitted in order to obtain a clear drawing.

The glass sheets are guided at intervals one after the other on the drive rollers in the transport device 1 to the transfer location. Suction acting on the suction chambers 5 causes a glass plate S, as it is introduced under the rollers 3 at the first place formed by the end rollers 1 of the drive device, to be held by suction with its upper side in contact with the peripheries of the rollers 3. The presence of the plate near the bottom of the suction chambers fretnbringsr asi begr3m$.i:u,g the airflow that occurs, due to the limited opening between the glass plate and the bottom of the first suction chamber, so that a reduced pressure is created above the plate and causes the plate to be lifted against the first rollers and then held against the rollers 3, which are driven to move this plate to be deposited on the rollers 14 at the second location while the plate is passed under the effective area of the suction and falls due to its own weight onto the upper side of the rollers 14. Alternatively, when the plate is just below the transfer point, suction can be interrupted briefly to drop the plate onto the storage table.

The height of the upper side of the rollers 3 above the level of the rollers 1 is

depending on the application of the appliance. If the apparatus is only to transfer glass plates of a certain thickness, the difference in level between the upper points of the peripheries of the rollers 1 and the lowest points of the peripheries of the rollers 3 is theoretically only equal to the thickness of the plate, but in practice slightly greater than this. If the device is to transfer plates of different thickness without adjusting the level of the rollers 3 for each thickness, then the difference in level will be slightly greater than the thickness of the thickest plate to be transferred. If the device is to carry out a predetermined lifting of the plate, e.g. transfer it over an obstacle,

the difference in level must be set accordingly.

Where the difference in level is not too great, there is suction

is normally exerted on the glass plate sufficient to effect an initial lifting of the plate into engagement with the drive rollers 3. If, however, the level difference is too great for the suction to effect an initial lifting, means must be acquired to start the initial lifting of the plate up to an area where the suction can work, i.e. sufficiently close to the underside of the suction chamber to provide the necessary reduced pressure to pull the plate into engagement with the drive rollers 3. Eg. the last roller or rollers in the transport device 1 can be mounted for a vertical movement to lift a plate supported on them, up to the vicinity of the suction at the transfer point, the leading edge of the plate being moved under the first suction chamber.

The release of the plate from the rollers 3 can be carried out only with the help of

of gravity when the plate is moved out of the effective area for the suction and falls under its own weight, e.g. down onto the rollers 14. Alternatively, the deposition of the plate can be carried out mechanically, e.g. by means of a roller or rollers mounted at the end of the transfer site, adjacent to the other site, slightly below the level of the rollers 3 so that they take the plate away from the action of suction and remove the air restriction thus interrupting the suction. Such a downstream roller or rollers can be mounted on a beam 4 slightly below the level of the rollers 3 or it can be mounted in an auxiliary frame, which can be moved vertically relative to the beams 4 to lower these rollers and thereby take the plate away from the rollers 3. The movement of such an auxiliary frame can be started by a limit switch, which is activated by a leading edge, or broken by the trailing edge of the plate being transferred as it is passed past the downstream end of the transfer location. Alternatively, the suction can be interrupted from at least the suction chamber or chambers located below or when the plate is below these chambers. This interruption of the suction can be controlled, e.g. by a limit switch, which is actuated by the advanced plate and acts to open the chamber or chambers to the atmosphere. In another method of carrying out the deposition of a plate, this can be done pneumatically by a suitably positioned air nozzle or nozzles or even by reversing the air flow through at least the downstream chamber(s) 5 so that air is blown through the bottom of these chambers and interrupts the suction thereby allowing the plate to fall down. This airflow from these chambers will also assist in pushing the plate downwards towards the rollers 14 at the other location.

Fig. 4 illustrates a modified form of the bottom plate in the suction chamber. Instead of being provided with holes 7 at an equal distance from each other, each bottom plate in each chamber is formed with a slot 15, which extends parallel to the rollers 3. Flg. 4 also shows additional rollers 16 which are mounted inside the suction chambers 5 with peripheries that protrude slightly through the slits 15 so that the lowest points of the peripheries of the rollers 16 are at the same level as the lower points of the rollers 3. The additional rollers 16 are at some applications desirable to prevent contact between the upper side of a glass plate being transferred and the suction chamber 5, especially when the plates are relatively thin and therefore flexible. The rollers 16 are driven with the same drive device as the rollers 3 or they can be run-on rollers.

When these rollers 16 are follow-up rollers, this can usually be achieved

a better advance of the glass plate, when these rollers are placed with their lowest points of the peripheries at a level only slightly above the lowest points of the peripheries of the rollers 3.

Figs. 5 and 6 show a further embodiment of the transfer apparatus which consists of a series of rollers 17 corresponding to the rollers 3 and mounted so that they can be driven together in a series of suction chambers 18 with the usual hood shape. Each roller 17 is mounted in its own suction chamber at a level so that the peripheries of the rollers protrude slightly through the openings 19 in the bottom plates of these suction chambers. The suction chambers are separated from each other in the hood by partitions 18a and the rings on the rollers protrude slightly through the bottom plates in the suction chamber.

The rollers are driven by a suitable chain connection around the chain drives 20 on the shafts for the rollers, these chain drives being mounted on the outside of the suction hood. An axle carries a drive device 21 with a connection to an external drive device.

The suction chambers 18 are connected to a common chamber 22 which leads

to a suction channel 23 and the roof of each of the individual suction chambers 18 is formed with a flow-limiting slot 24

of suitable size to prevent unwanted strong air flow when there is no glass plate present under the suction chambers. When a plate is present, the suction to the channel 23 causes a reduced pressure to be created around the rollers 17 so that the plate is held by suction against these rollers and is moved forward to the other location.

Fig. 7 shows a further embodiment of a transmission device corresponding to that in fig. 5 and 6. The individual suction chambers are omitted and the drive rollers 17 are placed in a common suction hood 18b, which forms the lower extension of a common chamber 22, which leads to the suction channel 23. In this embodiment, the drive rollers 17 are ordinary cylindrical rollers and placed closely next to each other with the outer drive rollers next to the end walls of the suction hood. The limited opening between the adjacent rollers 17 and the outer rollers and the end walls of the suction cap creates a limited airflow and thereby prevents unwanted strong airflow when there is no plate under the rollers 17. The gaps between the peripheries of adjacent rollers 17 and between these rollers and the end walls of the hood are of a size such that the restriction of the air flow provided by this is of the same order of magnitude as provided by the opening between the upper side of a glass plate being transferred and the lower edges of the walls of the suction hood 18. The rollers 17 can protrude from the bottom of the suction hood at a distance of approx. 1.2 mm. When a glass plate is under a part of the hood and effectively closes a space between adjacent rollers, a reduced pressure is created in the space bounded by the rollers and the glass plate and the plate is held against the rollers 17 by suction.

Fig. 8 shows how the simplified device in fig. 7 may be modified to provide more separate suction connection to the spaces between adjacent rollers. A choke plate 24

with throat holes 24a are placed over the spaces between adjacent rollers and between the end rollers and the end walls of the hood 18. A plurality of flexible flaps 24b are mounted and hang down from the plate 24 to rest on the drive rollers 17. In this way, the spaces between adjacent rollers 17 and between the upstream and downstream rollers and adjacent end walls of the hood 18 effectively separated from each other. The flaps 24b are sufficiently rigid to prevent an unwanted air flow between each flap and the roller on which they rest.

Fig. 9 and 10 illustrate stacking of the plates using such equipment. Glass sheets are sent along a roller conveyor 25

to a position below the transfer apparatus generally denoted by 26. This transfer apparatus has the same construction as illustrated in fig. 1 to 3. At the first location on the conveyor 25 below the transfer apparatus 26, the glass plates are sucked against the rollers 3 and are thereby moved in a direction normal to their forward direction on the transport device 25 to another location, which constitutes a stacking location generally denoted by 27.

At the stacking place 27 there is a receiving table 28 above which the end rollers 23 are mounted on a vertically movable frame 29, which

can be moved by an impact mechanism so that the rollers 3 on

the frame 29 projects slightly below the level of the lowest point of the peripheries of the other rollers 3. As a sheet of glass is guided in the direction of the arrow towards the stacking place, the leading edge of the sheet engages under the rollers of the frame 29, which mechanically takes it away from the suction of the transfer apparatus and thus interrupting the suction and allowing the plate to fall towards the receiving table. A stationary stopper 30, which has a rubber face, is placed

to receive the leading edge of the plate which is dropped onto the table.

This stops the movement of the plates and ensures to some extent that

the plates come into place in the stack on the stacking table. The drive connections for the rollers on the frame 29 are arranged to adapt to the vertical movement of the frame.

Instead of using rollers on the frame 29, it can be placed

other devices to interrupt the suction. The plates can be lowered by interrupting the suction in the downstream suction chambers.

During operation, glass plates are guided one after the other along the transport device 25 to the first place under the transfer apparatus 26 where a limit switch 40, which is actuated by the leading edge of each plate, stops the operation of the transport device 25. Suction is then carried out in the transfer apparatus 26 so that the plate is lifted and at suction held firmly against the rollers 3, which are now driven to transfer the plate to the second place at the stacking place. The plates fall one after the other onto the receiving table 28 and when each plate is deposited on the transport device 25 this is started again to bring the next plate under the suction transfer apparatus. As each plate falls onto the receiving table, this table is lowered in steps corresponding to the thickness of one plate at a time so that each plate deposited from the transfer apparatus falls only a short distance and a stack of plates is gradually built up on the table.

When a stack is completed it is removed from the table for packing or storage and the table is raised back up to its top position to form another stack. In addition to the stopper device 30, other devices can be used, e.g. air jets to place the successive plates one after the other

when they are formed in a stack and if desired it can be blown

a material that separates them from each other, e.g. wood flour, on

the upper side of each plate when stacked, thus avoiding abrasion between the plates. The transport device 25 can carry single plates one after the other or it can carry portions of plates placed side by side on the conveyor belt, each portion consisting of several plates. In this case, the transfer apparatus simultaneously picks up all the plates in a portion and transfers these plates one after the other to the stacking location. Fig. 11 illustrates a stacking arrangement in which the transport device 25 is aligned with the transfer apparatus and the stacking location. With this arrangement, the transport device 25 is continuously active and the suction is continuously performed on the transfer apparatus, which is arranged so that its rollers 3 move the plates forward at the same speed as the speed of the plates on the transport device 25. Fig. 12 illustrates a selective stacking device in which the transfer apparatus 26 extends over several stack spaces, indicated

at 31, 32 and 33 where the plates are selectively stacked according to size. Each location has a detector device 34, which measures the size of a plate carried by the transfer apparatus 26 by engagement between the leading edge and the trailing edge of the plate. Each detector device is connected to a control location whose measurement result is connected to devices for driving a vertically movable frame 35, which carries the end rollers 3 above each location so that these rollers are movable from a raised position in line with the rest of the transfer rollers 3 to a lower position below the level of the lowest point of the peripheries of the other transfer rollers 3. When a detector device 34 measures that the plate being moved is off

a size determined for a particular stacking location, the control devices to which it is connected lower the corresponding frame 35 so that the plate is removed from the suction above the stacking location and placed in this location.

The place of selective deposition of the plates can be automatic

controlled or controlled by an operating device from a control panel. One of the stacking locations may be reserved for defective or damaged plates and an automatic inspection device may be provided in the transfer apparatus to detect such plates

and to control the apparatus so that such plates are placed at the reserved place.

It is common to deposit slabs at appropriate locations based on a selective size. At least two storage locations for each plate size are preferred so that plates of a given size can continue to be taken to one location, while a stack of plates of this size is removed from the other location.

The transfer apparatus 26 in fig. 9 and 10 may have any of the forms illustrated in fig. 1 to 3 or fig. 1, 2 and 4 or fig. 5 and 6 or fig. 7 or fig. 8.

In the drawings in fig. 9, 10, 11 and 12 show mechanical devices for interrupting the suction and releasing a plate. However, fig. 13, 14 and 15 a preferred embodiment, in which the deposition of a glass plate is carried out by controlling the suction exerted on the plate. Fig. 13 shows parts of a transfer apparatus for use in a selective stacking device of the type shown in fig. 12, in which a majority of stacking locations are used. The part of the apparatus shown in fig. 13 is for use over one of the stacking locations, similar transfer equipment is placed over each of the other stacking locations. In use, a succession of glass plates is moved in the direction of the arrow by means of the drive rollers 3. The plates are held against the lower peripheries of the rollers 3 by suction. The rollers 3 are mounted inside a suction chamber with a roof

50. The openings 51 and 52 are arranged in the ceiling above the rollers and the suction is carried out at these openings from a hood (not shown) in a similar way as in fig. 7 and 8. The rollers 3 are placed closely so that the openings between the rollers provide a limited air flow when there is no glass plate under the rollers. Mounted on the underside of the roof 50, a number of flaps 53 are mounted so that they can swing on shafts 49, which can rotate selectively and are held in position by spring bolts 54 (Fig. 14) so that a flap is lowered, as indicated at 53a, for to lie close to the roller below it and thereby effectively close off a part of the suction chamber between the flap 53a and a certain locking flap 54 which is placed at the end of the suction chamber close above one of the rollers 3. The flap 53 which is lowered is chosen in accordance with the length of the glass plate is transferred so that the distance between the flaps 54 and 53a is approximately equal to the length of a plate. As a sheet of glass is passed under the rollers 3, it is held against the rollers by suction existing on both

sides of the flap 53a due to the two openings 51 and 52.

As the plate is moved forward, the leading edge of the plate breaks a

switch 55 (fig. 15) which starts a pneumatic cylinder which controls a rotatable damper 56 located in the opening 51. The damper 56 is moved so as to interrupt the suction through the opening 51 and the air then flows past the plate and between the rollers 3 to reduce the vacuum in the part of the suction chamber between the flaps 53a and 54. The switch 55 is positioned so that the vacuum is released when the plate lies immediately below the part of the suction chamber between the flaps 53a and 54. In this way, successive plates can be dropped in a specific position onto a stacking table or a trolley 57 to then form a stack of plates 58 with the leading edge of the plates against the stopper device 30 as indicated in fig. 15.

When the vacuum between the flaps 53a and 54 is reduced, the air flow into this part of the suction chamber is very strong and has the effect of pushing the plate downwards. The purpose of dividing the suction chamber into two parts by lowering one of the flaps 53

is that when suction is reduced in a portion of the suction chamber to the left of the submerged flap, suction is maintained in the chamber to the right of the submerged flap due to opening 52. Consequently, as one plate falls onto the stack, other plates become right of the submerged flap still held against the rollers by suction. If a plate that is moved past the rollers is not to be stored on the stack, then the damper part 56 becomes

not moved to reduce suction so that the plate continues to be held by suction and is moved on to a similar transfer apparatus over the next stacking location.

As shown in a plan section in fig. 14, the apparatus includes a number of horizontal channels which are arranged side by side in an integrating unit, each channel being as shown in fig. 13. Fig. 14 shows only half the width of the entire apparatus and this half includes four channels 60, 61, 62 and 63. Vertical partitions 64, 65

and 66 extends horizontally and provides separate suction chambers for the different channels. The damper parts 56 for each channel are

mounted on a common shaft and the shaft 49 for the rotating flaps 53 extends over the entire channel. In this way, the position of the damper parts 56 and the flaps 53 is always the same in each channel.

By dividing the suction area into a number of separate narrows

channels, glass sheets of different widths can be processed. The spaces between the partitions 64, 65 and 66 are half

of the narrowest plate width that can be processed so that for all plates used, at least half of the plate's surface will be exposed to suction.

Fig. 15 shows mechanical pushers 70 which are moved by double-acting pneumatic cylinders 71. The pushers 70 grip the rear edge of each plate as it has fallen onto the stack 58 in order to

avoid a push back from the fixed stop device 30. The cylinders 71 are provided with air pipes 72, which are connected to

a four-way solenoid valve 73. The solenoid valve 73 is connected to an air supply at pipe 74 via a filter 75, regulator 76

and a lubricator 77. The switch 55 is connected to a control unit 78 connected to a direct current source via connection points 79. The control unit 78 provides an output at the connection points 80 for connection to a solenoid valve which controls the operation of the damper device 56

depending on the operation of the switch 55. Another delayed output is provided at the connection points 81 connected to a solenoid valve 73 to control the operation of the pneumatic cylinders 71.

The example shown in fig. 16 is substantially similar to that shown

in fig. 8. Each roller 3 in the cap, except the first roller 3a is connected by a flexible flap 80 which is in contact with the periphery of the roller to provide a separate suction chamber with a separate suction exercise for each roller. The first roller 3a is a drive roller, but it is narrow and has rings. Above the roller 3a is an opening 81 which provides a small air resistance. During operation,

as the glass plate is passed under the rollers in the direction of arrow A, it forms a bridge between the opening of the first roller 3a and the next roller 3, thereby providing a limited air flow so that the suction can be exerted over all the rollers and the plate is held against them by suction. When the trailing edge of the plate passes past the first roller 3a and ceases to provide such a limited air flow, the opening 81 allows a large air flow so that the vacuum is reduced over the others

the rollers and the glass plate fall onto the stack 58. Adjustment flaps 53 according to size are placed for the same reason as previously described with reference to fig. 13. Each flap 53

is built into a separate chamber and when it is lowered it closes off a hole in the side wall of the chamber. In this way, the suction is not released for all the rollers holding a plate perpendicular to the submerged flap. An adjustable restriction device 82 is placed over the opening 81 with low resistance so that the required air flow can be adjusted. A damper part 56

is placed in the opening 81 so that when it is necessary for a plate to be sent on without being placed on the stack 81, the damper part 56 can be moved by a pneumatic cylinder to limit the opening 81. The previously described disconnection effect will not occur. Fig. 16 also shows air nozzles 83 to direct air between the top of the stack 58 and the next plate falling onto the stack. Fig. 17 shows a further embodiment in which the suction is released by passing the rear edge of the plate over the first roller in the suction chamber. The operation is generally similar to that described for fig. 16. In this case, the damper part is placed on the first roller 3b which is shown more clearly in fig. 18. The roller 3b consists of two freely rotatable disks 85 and 86 with the valve damper plate 87 placed between them. A pneumatic cylinder 88 and a crank connection are arranged to move the plate 87 between open and closed positions. An adjustable opening 90 with little resistance is arranged above the first roller 3b. With the damper part 87 open, the airflow passes the plate 87 when the rear edge of the plate is clear of it, thereby reducing the vacuum above the rollers 3 and allowing the plate to fall onto the stack. When the damper part is closed or almost closed, this provides a high resistance to the air flow and the plate will not fall down. In this case, the previously described adjustable flaps 53 are replaced by size by an adjustable rod 91 which carries a closing device 92 on the end. The rod is moved axially to locate the rod device 92 at the relevant location depending on the length of the plate being used. The locking device 92 thereby separates the suction chamber into two parts. One part has the hole 90 and the other part has the adjustable suction hole 93 on the opposite side of the locking device 92. The suction is not reduced in the other part of the suction chamber when the plate falls onto the stack.

In the embodiment as shown in fig. 17 and 18, the roller 3b is not driven.

In an alternative construction, the roller 3b in fig. 17 and 18 be replaced by the arrangement shown in fig. 19. In this case, the roller 3c is driven and is a smooth cylinder similar to the other rollers 3. However, it is placed at a distance from the next rollers sufficient to provide a low resistance to the air and the damper valve plate 9 4 is placed between the first and the second the roller so that it can be operated to increase air resistance when a plate is to be transferred and is not dropped. The operation of the modified embodiment shown in fig. 19, on the other hand, is the same as already described in fig. 17.

It will be understood that the examples in Figs. 16 to 19 can be

used for selective stacking with several stacking places of the type shown in fig. 12. Further, a complete apparatus includes a number of parallel channels with partitions providing separate suction chambers located across the conveyor belt, as described in fig. 14. -

The invention thus provides an improved transfer apparatus for glass plates which is particularly applicable in automatic warehouses for the selective storage of glass plates according to their size.

Claims (1)

Apparatus for transferring plate material, particularly glass plates, from a first location to another location, comprising an open bottom suction hood and extending along a transfer path between said locations, a series of drive rollers arranged in the open bottom of the suction hood so that they in contact with the upper side of a plate which is sucked against the drive rollers by means of a negative pressure in the suction cap, so that the plate is thereby carried forward along the transfer path, as well as devices which are affected by the plate's movement to reduce the suction in the suction cap in order to release a plate from the rollers , characterized in that it comprises a separate release chamber (18) delimited in the suction cap adjacent to the second location with devices (56) in connection with the release chamber to reduce or interrupt the suction therein.