AN APPARATUS FOR PERFORMING THE METHOD, AND USE OF BOTH THE METHOD AND THE APPARATUS The invention relates to a method of removing a cover sheet adhering to a plate and in the rim area/areas of the plate. The invention also relates to an apparatus for performing the method, and use of both the method and the apparatus.

Finally, the invention relates to a work station.

In connection with the handling of plates of different types, e. g. window panes either of glass or of plastics material, and also other plates where it may be desirable that the surfaces are kept intact and without scratches, these surfaces will normally be covered with a suitable sheet. This sheet adheres to the underlying plate, either by a corona effect, i. e. static electric- ity, or by means of an adhesive. There are many forms of methods and ap- paratuses for removing this sheet subsequently, and such methods are dis- closed e. g. by the Japanese applications having the publication numbers 10297816,11322186,514728.

However, none of these apparatuses and methods discloses how the sheet may be removed in selected areas on the plate. Such a method is expedi- ent in connection with plates where a working or joining process has to be carried out at the rim area of the plate, or the plate has to be mounted in a frame or the like, it being desired at the same time that the predominant plate area should be protected by the sheet, e. g. pane elements which are to be arranged in gates, doors and in windows, it being desirable here to remove the sheet in the entire rim area corresponding to 2-3 cm measured from the edge and inwards toward the centre of the plate and then to place them in the opening of the gate. This is to ensure that the surface remains

protected during transport, while, of course, it is necessary to expose the rim areas in order to achieve the necessary adhesion in the frame or to avoid conflict with seals-sealing elements. The way this is done today, it is exclusively a manual operation, comprising manually cutting away sheet in the rim area by means of a template placed over the plate and manually removing the sheet. However, this a very time-consuming process, and also involves the risk of damaging the underlying plate, and, in case of un- fortunate dimensioning, such damage may be present within the visible area.

Accordingly, the object of the present invention is to provide a method and an apparatus which solve the above-mentioned problems, it being thus possible to perform automated removal of cover sheet in the rim areas on plates, which must be covered by such a sheet in general.

This is achieved with a process of the type defined in the opening para- graph, and where also a pressure element carrying a tape adhering to the cover sheet in a first area is caused to contact the cover sheet in a rim area, where the cover sheet disposed in the first area is subsequently loos- ened in a second area from the underlying plate and adheres to the adhe- sive tape, and where a cutting/separating instrument in the second area subsequently separates the sheet adhering to the adhesive tape from the remaining cover sheet.

The plate, which must thus have removed its sheet in the rim areas, is transported via an expedient transport device to the apparatus, where at least a sensor, preferably a photocell, records the front edge of the plate/pane. A pressure element, preferably in the form of a rotatable roll/drum around which an adhesive tape is placed with the adhesive side facing toward the plate, is caused to engage in the rim area and substan- tially corresponding to the width which is to be removed. The tape will now

adhere to the cover sheet itself and with an adhesive force which exceeds the adhesion which exists between the cover sheet and the plate.

After contact in what is here called the first area, the adhesive tape will have a direction of movement such that the tape is moved with the adhe- sive face with sheet away from the plate itself, whereby the cover sheet in the rim area will be lifted from the plate itself. The first area will typically comprise an additional pressure roll placed after the tape pressure roll has applied tape. The additional pressure roll serves to press the tape firmly against the sheet and therefore typically has a face of attack which is 1-1.5 mm closer to the pane. A cutting instrument, e. g. in the form of a knife whose cutting edge faces toward the direction of movement of the plate and the adhesive tape, will separate the lifted sheet from the remaining sheet, and then the adhesive tape with sheet disappears on a second instrument, e. g. in the form of a roll on which the adhesive with sheet is wound. The second instrument, however, may also be configured as a vacuum machine if desirable. Typically, the cutting instrument and the additional pressure roll has interposed between them a flat metal member across which the tape runs before separation of the rim sheet takes place.

The structure may also be configured such that the plate/pane is stationary, while the pressure element itself is moved relative to the plate.

As mentioned, the actual instrument for separating the rim area may be formed as a knife with the cutting edge facing toward the direction of movement, and with the tip penetrating the lifted sheet, but, of course, it may also be configured in another manner, e. g. as a circular saw having a direction of rotation in or against the direction of movement. Alternatively, this separation device may be configured in another way than as a knife, e. g. a laser may be used which operates in a wavelength expedient relative to the plastics.

Typically, 4 stations will be active at the same time, viz. 2 corresponding to the lower rim side of the pane and on the front and rear sides and 2 upper ones corresponding to the upper rim side of the pane and on the front and rear sides.

By providing a method according to the invention and as additionally stated in claim 2, it is ensured that a distinct and firm adhesion is achieved be- tween the adhesive tape and the sheet.

By providing a method according to the invention and as additionally stated in claim 3, it is ensured that the activation of the apparatus takes place at the proper location. It should be mentioned here that the activation may be such that it takes place on both of the two long sides at the same time and on the upper side as well as on the lower side of the plate. Subsequently, a corresponding cutting-away of sheet will typically take place on the two short sides, as the instruments (in the form of pressure elements and knife/separation instruments), which are to be moved now, will have a di- rection of movement perpendicular to the long sides. Optionally, it suffices merely to turn the plate itself where the rim area is to be cut away.

By providing a method according to the invention and as additionally stated in claim 4, an expedient configuration of the pressure element is achieved and in such a manner that a distinct, tight location of attack on the cover sheet is obtained.

By providing a method according to the invention and as additionally stated in claim 5, it is ensured that the sheet does not curl or stretch, but that an expedient removal of the rim area takes place.

By providing a method according to the invention and as additionally stated in claim 6, it is ensured that the waste resulting from the process, viz. the

rim sheet itself, is disposed of in a simple and distinct manner. Optionally, this sheet, which has thus been wound on to the tape, is subsequently treated such that tape and sheet are separated and the tape is optionally re-used.

By providing a method according to the invention and as additionally stated in claim 7, an expedient width and an expedient force of attack on the rim area are achieved.

The invention also relates to an apparatus as defined in claim 8, which pro- vides the advantages mentioned above. This apparatus is arranged such that the transport device may e. g. be rolls, which partly have their point of attack on the edge of the plate, as the plate may be placed edgeways, and partly roll perpendicularly to these to ensure that the plate does not tip, fol- lowing which the pressure element will be activated as soon as the front edge of the plate reaches the area of activity. The adhesive tape is thus caused to engage the rim areas on preferably both the upper and the lower rim area and preferably on both sides of the plate, and then the cutting in- strument is subsequently caused to engage corresponding to exactly the area at which the desired width of the separated cover sheet is achieved.

Claims 9-11 define additional expedient embodiments, including, as stated in claim 11, a sensor which detects the front edge of the plate.

The invention is particularly useful for plates as stated in claim 12 and for plates as stated in claim 13.

Finally, the invention relates to a work station as stated in claim 14, which work station is composed of the components according to claims 8-11 and by performance of the method according to claims 1-7.

The invention will now be explained more fully with reference to the draw- ing, in which fig. 1 shows a detail view of the construction area where the pressure element exerts its pressure on the rim area of the plate, fig. 2 shows a plate with cover sheet removed in the entire rim area, fig. 3 shows an example of the apparatus according to the invention, fig. 4 shows a detail view of the construction area where the pressure element exerts its pressure on the rim area of the pane, and where the knife arrangement is different from that shown in fig.

1, fig. 5 shows a work station for performing total delamination in the rim area.

Fig. 3 shows a work station for removal of sheet on the longitudinal sides of a plate 1, said plate 1 being in this case a transparent pane which is cov- ered with a cover sheet 2 on the upper as well as the lower face. Adhesion between cover sheet and plate takes place by means of an adhesive or by static electricity. The plate is advanced via a transport device 12 to the ap- paratus where the rim area of the plate is exposed. The apparatus com- prises a roll of tape/adhesive 15 spaced from the actual area where the process is carried out. From there, the adhesive tape/strip 15 is moved with the adhesive side facing toward the plate 1 across a pressure element 4 which is configured as a rotatable wheel. The adhesive sheet is passed on to another roll, the so-called second element 11, which is likewise config- ured as a drum around which the used tape with cut sheet is wound.

It should be noted that the second element 11 is positioned relatively to the pressure element 4 such that the second element 11 is disposed after the pressure element has performed its function, and that the outer periphery of the second element is spaced from where the pressure element is active. If this is not the case, the adhesive tape 5 would not have a pull direction away from the plate.

In addition, the construction comprises a cutting/separating instrument 8, which may be constructed in various ways, and which, in this case, is con- structed as a rotating saw cutter and so that the cutting edge contacts the cover sheet after the pressure element 4 has performed its function on the plate. It should be noted that the station is constructed such that it is con- figured symmetrically around the surface extent of the feed direction of the plate, so that delamination of the longitudinal rim area 3 takes place on the upper part of the plate as well as on the lower part of the plate.

The actual function of the pressure element will now be described with ref- erence to figure 1.

This shows a detail view of the area of function, and where a plate 1 with a cover sheet 2 is transported to the area of activity of the apparatus accord- ing to the invention with its front edge 13 at a vertical level, and where a first sensor, which is illustrated in figure 3, detects the beginning of the front edge. The same sensor 9 can thus also detect the rear edge of the plate so that the length of the plate is calculated. This is of importance when the plate is to be delaminated later, as far as the two width sides in the rim area are concerned.

After the sensor has recorded the front edge, activation of the pressure elements 4 will take place, said pressure elements being here configured as rolls optionally coated on their outer periphery with a friction-increasing

means and having a width which at least corresponds to the width of the adhesive strip/tape 5. This adhesive tape is fed from an adhesive roll 15 which is spaced from the actual area of action. The adhesive tape faces inwards toward the pressure element 4 with its non-adhesive side, and with its adhesive side it thus faces toward the plate 1 which passes into the area of action of the pressure element. In the so-called first area 6, a pressure impact is applied to the plate in the rim area, as the adhesive tape/strip 5 is pressed against the rim area in a predetermined width corresponding to the width of the tape or smaller. Support rolls 14 ahead of the area of activity ensure that the plate has the correct position and does not deviate from the plane which is vertical in this case. In a subsequent area, the tape will ex- tend level with the face of the plate to thereby increase the adhesion be- tween the adhesive tape and the cover sheet 2 itself.

At a distance from this, the so-called second area 7 is then reached, in which second area 7 the tape with the adhered sheet is removed, said tape being wound on to a roll/wheel, so-called second element 11, in such a manner that the tape forms an angle of preferably between 30 and 90° with the horizontal plane of the plate. A cutting/separating instrument 8 is ar- ranged in the vertex of the angle itself and in the second area, and where in figure 1 a stationary knife is shown, which substantially corresponds to a razor blade in shape, and with its tip penetrates the cover sheet loosened from the plate so that this cover sheet removed in the rim area and adher- ing to the tape is now wound on to the second element. The knife structure may also be shaped differently, as is shown in figure 4, using a knife 8 which is a rotating saw blade. Here, too, the cutting edge will be active in the area after the first area and referred to as the so-called second area.

In figure 1 as well as in figure 4, removal of the sheet takes place in the rim area on both the upper and the lower face of the plate, it being observed that figure 1 shows an arrangement where the plate is oriented vertically

with its face, while in the arrangement of figure 4 a case is shown where the plate is oriented horizontally with its face. It is observed that some of the rolls are driven by means of drive belts 16.

Figure 2 shows an example of a plate 1 covered with a cover sheet 2, and where cover sheet is removed in the rim area 3. This plate is also suitable for being inserted e. g. into the opening in a gate, as the actual face visible in the gate is still protected by a cover sheet, while the sides to be inserted into the recess in the opening are exposed.

Figure 5 shows a work station where delamination of the entire rim area on plates is carried out, and where this takes place in an automated manner.

As described before, a plate will be transported into the first station 17, with the face oriented vertically. Delamination of the two rim areas now takes place, corresponding to the longitudinal direction of the plate on the front side as well as the rear side. Subsequently, the plate is moved to a second substation 18, in which, instead of the plates being moved for delamination of their rim areas in the width direction, the pressure element is moved so that it performs a vertical movement in the rim areas.

To automate the process as expediently as possible, it is here arranged such that the first plate has its cover sheet removed vertically down along its front edge. The first roll is then moved to a waiting position, and then the next plate is moved to the area of activity, and the rear edge of the first roll is now moved to the front edge of the second roll. Subsequently, a strip is now moved down, as described before, and in this case it will be the pres- sure element 4 which moves, and in this process a suitable rim area on the rear edge of the first roll is removed, corresponding to the width thereof, and also on the front edge of the second roll. In the second area there will thus be 2 cutting instruments activated relatively to their respective plates.

The first roll is now removed, as the cover sheet has been removed from it

in its entire area, and the second roll is moved to a waiting position, follow- ing which the third plate is moved to the area of activity for the pressure element 4, and the second roll is moved to the front edge of the third roll, so that the rear edge of the second roll adjoins it. The process is now re- peated, so that the rim areas of the front edge of the third roll and of the rear edge of the second roll, corresponding to their width, are now exposed by means of a single strip and the two mentioned cutting instruments.

The process is thus automated, as delamination of two rim areas may be performed by a single run. The apparatus and the method may be used for transparent plates having a cover sheet as well as for non-transparent sheets having a cover sheet. The plates may be made of metal, glass or plastics, the essential point being that these are protected on their plane faces by a sheet suitable for the purpose, which adheres to the plates either by an adhesive itself or by static electricity. Of course, it is also essential to the invention that the adhesive effect between the cover sheet and the ad- hesive tape 5 is greater than the adhesive effect between the cover sheet and the underlying plate.

A typical work station may thus be constructed as follows : The pane is inserted into the machine so that the photocells, which are ar- ranged in the inlet, scan: First, these photocells adjust the height of the two upper tape stations so that these exactly fit the height of the plastics pane.

When the height has been adjusted, the four tape stations are closed around the plastics pane in that the two stations, which are provided on the front side of the plastics plate, are moved toward the plastics plate by means of compressed air.

The plastics pane is now secured between the four tape stations, and the entire pressure from the four tape stations is transferred through the inlet roll which is arranged on each of the four tape stations.

Shortly after the plastics pane has been secured by the 4 inlet rolls, 4 elec- tric motors begin to pull the pane through the 4 separate tape stations.

After the pane has been advanced about 100 mm in the tape station, the pane reaches the next roll (tape applicator roll). This roll, too, is driven, but is not arranged on the same line as the inlet roll.

This tape applicator roll is positioned 1-1.5 m further inwards in the direction of the thickness of the pane. (This means that focus and pressure are re- moved from the inlet roll and to this tape applicator roll.) Tape is now applied to the pane via this tape applicator roll, and at the same time the friction between roll and tape ensures that the pane contin- ues to be driven forwards through the process.

After another about 100 mm the pane arrives at the next roll (pressure roll).

This roll is mounted a further 1-1.5 m ahead of the tape applicator roll. This means that we again have a new focus point, as the focus point is removed from the tape applicator roll and to this pressure roll, and we ensure thereby that the tape is additionally pressed firmly on to the pane to ensure the contact between tape and sheet on the pane. This pressure roll is a non- driven roll.

After the tape has been pressed additionally firmly on to the sheet by this pressure roll, which is mounted centrally in a 150 mm long and 6 mm thick steel plate, tape and sheet are to be pulled off the pane.

This takes place over the end of this steel plate (which has been bevelled with an angle of about 10° relative to vertical, such that the corner of the pane is the first part that gets clear of this steel plate. This means that focus is directed toward pulling the tape off the corner on the pane and not over the entire vertical end of the pane).

The face of this steel plate is arranged at an angle of 3-4° relative to the face of the pane and such that the end around which the tape and the sheet is to be pulled off, is 0.5-1 mm from touching the pane.

When the tape and the sheet begin to leave the plastics pane, the sheet is to be broken to prevent the sheet from being removed from the entire plas- tics pane, but only from an area of about 20 mm from the boundaries of the pane.

This takes place by means of a knife positioned at the same angle with the pane as the above-mentioned steel plate.

The tape with the now adhered part of the sheet about 20 mm is fed via a plurality of rolls (to ensure uniform tension in the sheet across the inclined face on the steel plate) to a collection roll for used tape.

After a further 100 mm there is a driven discharge roll. This roll is disposed at the same plane as the pressure roll. The discharge roll, together with the inlet roll, is to ensure that the speed of the pane through the entire process remains the same.