Abstract:
The invention describes a method and an apparatus removing a plurality of die-cut products from an operating area of a die-cutting apparatus having multiple dies. The die-cut products are simultaneously picked up at a pick-up point in the operating area. Then they are simultaneously moved to a delivery point outside the operating area. At the delivery point, the die-cut products are released simultaneously. The operations of picking up moving and releasing are carried out in such a manner that the die-cut products at the delivery point are situated at substantially at the same position with respect to one another as those which they adopt at the pick-up point.

Description:
This is a continuation of Application No. PCT/NL01/00516, filed Jul. 6, 2001. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a method for removing a plurality of die-cut products from an operating area of a die-cutting apparatus having multiple dies. 
     BACKGROUND OF THE INVENTION 
     A die-cutting apparatus having multiple dies cuts a plurality of products out of a base material in a single stroke. For this purpose, the base material is positioned between a top table and a bottom table, on which the dies are arranged. During the die-cutting, the bottom table and the top table are pressed against one another and the dies penetrate into the base material. A stroke consists in the bottom table and the top table being moved towards one another, a die-cutting operation and the bottom table and top table being moved away from one another. The operating area of the die-cutting apparatus is formed by the area where the dies are located. 
     The base material is fed continuously to the die-cutting apparatus and is shaped as a long strip which slides onwards a certain distance after each die-cutting operation. The strip of base material is supported by conveyor rollers. 
     After each die-cutting operation, the die-cut products have to be removed from the dies. It is known to use a blowing device for this purpose, which blows the die-cut products off the dies, after which they are collected. It is also known to use ejectors which eject the die-cut products from the dies, after which they are likewise collected. The products are generally removed in a direction which is at right angles to the direction in which the strip of base material slides onwards. 
     When using multiple dies in a die-cutting apparatus, it may be necessary for the die-cut products to be sorted on the basis of origin. In this case, after the die-cutting, die-cut products. originating from a specific die must not be mixed with die-cut products originating from a different die. If the die-cut products are blown off or ejected from the dies, it is not easy to ensure that this is the case. Moreover, methods of this type for removing the die-cut products from the dies have the drawback that it is not altogether certain whether all products will reach a location which is designated for their collection. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a method for removing a plurality of die-cut products from the operating area of a die-cutting apparatus having multiple dies, in which die-cut products which originate from different dies are not mixed with one another and in which the die-cut products reliably reach the location which is designated for their collection. 
     This object is achieved by a method which comprises the following steps: substantially simultaneously picking up a plurality of die-cut products at a pick-up point in the operating area; substantially simultaneously moving the die-cut products from the pick-up point to a delivery point outside the operating area; and substantially simultaneously releasing the die-cut products at the delivery point; the die-cut products being fixed with respect to one another at positions which substantially correspond to positions with respect to one another which they adopt at the pick-up point. 
     The method advantageously comprises the following step: moving the die-cut products from the delivery point to a discharge point located outside the die-cutting apparatus; separate die-cut products being held at different positions. 
     The method is preferably characterized by moving a transfer member between the pick-up point and the delivery point; bringing the transfer member into an operative state when it is at the pick-up point; and bringing the transfer member into an inoperative state when it is at the delivery point; the transfer member being designed to pick up a plurality of die-cut products at the pick-up point and to release the die-cut products at the delivery point, said transfer member also being designed to fix the die-cut products with respect to one another at positions which substantially correspond to positions with respect to one another which they adopt at the pick-up point. 
     The die-cut products are always removed from the operating area of the die-cutting apparatus between two die-cutting operations. For this purpose, the transfer member is moved to the pick-up point after each die-cutting operation, the pick-up point being the location where the products are situated after the die-cutting. The transfer member is then activated, so that it is able to pick up the die-cut products. This takes place in such a manner that the die-cut products substantially retain their positions with respect to one another. Then, the transfer member, together with the die-cut products is moved to the delivery point, which is located outside the operating area of the die-cutting apparatus. At the delivery point, the transfer member is deactivated, with the result that the transfer member releases the die-cut products. The positions which the die-cut products adopt with respect to one another at the delivery point substantially correspond to the positions with respect to one another which they adopt at the pick-up point. 
     The die-cut products are advantageously moved onwards from the delivery point to a discharge point located outside the die-cutting apparatus, where, by way of example, they are collected in receptacles. When the die-cut products are being moved onwards, they are held at different positions, so that products which originate from different dies are not mixed with one another. 
     If the die-cut products comprise a material which can be attracted by magnetic forces, the transfer member preferably comprises an electrically actuable magnet. 
     The invention also relates to a die-cutting apparatus having multiple dies and to a removal device for removing a plurality of die-cut products from an operating area of a die-cutting apparatus having multiple dies. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The method according to the invention and a preferred embodiment of a removal device for use with this method will be explained in more detail in the description which follows with reference to the appended drawing, in which identical reference numerals denote identical or similar components, and in which: 
     FIG. 1 shows a side view of a removal device according to the invention, in a pick-up position; 
     FIG. 2 diagrammatically depicts the removal device shown in FIG. 1; 
     FIG. 3 shows a side view of the removal device according to the invention in a delivery position; 
     FIG. 4 diagrammatically depicts the removal device shown in FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a removal device for removing a plurality of die-cut products from the operating area of a die-cutting apparatus having multiple dies. The removal device is denoted overall by the reference numeral  1 . 
     The removal device  1  comprises a transfer member which can be moved in linear fashion and is denoted overall by the reference numeral  10 . The transfer member  10  comprises an extraction head  11 , which in this example is designed as an electrically actuable magnet, and a transfer rod  12 , the extraction head  11  being arranged at a first end  13  of the transfer rod  12 . Over a section of its length, the transfer rod  12  is surrounded by a guide  14 , which is provided, for example, with a ball jacket, by means of which the transfer rod  12  can be supported successfully and can be guided with the minimum possible play. The guide  14  is attached to a holder  15 , for example by means of screws, and the holder in turn, in the installed state, is connected to a bottom table, which can be displaced in a vertical direction, of a die-cutting apparatus. In FIG. 1, the bottom table is shown by means of a dashed line, although only in part, and is denoted overall by reference numeral  50 . The bottom table  50  bears the dies, which are situated in the area which, in FIG. 1, is denoted by reference numeral  51 . 
     The transfer rod  12  may be designed as a single rod, but with a view to stability is preferably designed as a double rod, in which case the two rods are arranged substantially parallel to one another and-each of the two rods is supported and guided by a ball jacket in the guide  14 . 
     At its second end  16 , the transfer rod  12  is connected to a first end  17  of a first connecting rod  18 , it being impossible for the transfer rod  12  and the first connecting rod  18  to move with respect to one another. The transfer rod  12  and the first connecting rod  18  could therefore also be designed as a single unit. 
     At its second end  19 , the first connecting rod  18  is pivotably connected to a first rod head  20  of an adjustment rod  21 . The adjustment rod  21  is shaped in such a manner that its length can be adjusted as desired. In this example, the adjustment rod  21  comprises a connector  22  which is provided with an internal screw thread, two lock nuts  23 , said first rod head  20  and a second rod head  24 . Both rod heads  20 ,  24  are provided with a screw thread, one of the two rod heads  20 ,  24  and one of the two lock nuts  23  being provided with a left-hand screw thread, and the other of the two rod heads  20 ,  24  and the other of the two lock nuts being provided with a right-hand screw thread. The connector  22  is provided with both types of screw thread. The length of the adjustment rod  21  can be varied by turning the connector  22 . The lock nuts  23  are used to lock the connector  22 . 
     The adjustment rod  21  could also be designed with a fixed length. An adjustable length is advantageous if the removal device  1  is not arranged fixedly at one defined die-cutting apparatus, but rather must be usable for more than one die-cutting apparatus. 
     The first rod head  20  of the adjustment rod  21  is preferably connected by means of a ball joint to the second end  19  of the first connecting rod  18 , since a ball joint is able to absorb forces acting in different directions. Using a ball joint, any lateral movement of the adjustment rod  21  will be transmitted to a lesser extent to the first connecting rod  18  and the transfer rod  12  than when using a different type of joint. 
     At the second rod head  24 , the adjustment rod  21  is pivotably connected to a first end  25  of a rocker rod  26 . The rocker rod  26  comprises a first arm  27  and a second arm  28 , which are rigidly connected to one another at a fixed angle at a connecting section  29 . In this example, the first arm  27  and the second arm  28  are situated in the same plane, and the first arm  27 , the second arm  28  and the connecting section  29  are formed as a single unit. The connecting section  29  of the rocker rod  26  is rotatably connected to a fixed column  30 , the axis of rotation extending in a direction which is substantially perpendicular to the plane in which the first arm  27  and the second arm  28  are situated, a bearing preferably being used. 
     The second rod head  24  of the adjustment rod  21  is preferably connected to the first end  25  of the rocker rod  26  by means of a ball joint. 
     At its second end  31 , the rocker rod  26  is pivotably connected to a first end  32  of a second connecting rod  33 , which in turn, at its second end  34 , is pivotably connected to a support  35  which, in the installed position, is attached to the bottom table  50  of the die-cutting apparatus. 
     The removal device  1  comprises discharge chutes, which in FIG. 1 are jointly denoted by reference numeral  40 . In this example, the discharge chutes  40  are attached to the holder  15 . The number of discharge chutes  40  is at least equal to the number of dies used in the die-cutting apparatus, since only products originating from one die may be discharged in any one discharge chute  40 . Each discharge chute  40  comprises a collection end  41  for collecting the die-cut products and extends, for example, to as far as a receptacle (not shown) for collecting the die-cut products or a moving belt (not shown), by means of which the die-cut products are moved onwards. 
     The discharge chutes  40  may be made from steel U-sections, but may also comprise a different material or be of a different form. The shape of the assembly of discharge chutes  40  should be such, that the die-cut products in different discharge chutes  40  cannot be mixed with one another. 
     The transfer rod  12 , the first connecting rod  18 , the adjustment rod  21 , the rocker rod  26  and the second connecting rod  33  together form a system of rods which is used to enable accurate control of the movement of the extraction head  11  on the basis of the movement of the bottom table  50  of the die-cutting apparatus. The way in which this rod system operates, as well as the way in which the removal device  1  overall operates, will be described below with reference to FIGS. 1-4, FIGS. 2 and 4 only providing a diagrammatic illustration of the pivot points and the rods. 
     When the die-cutting apparatus is operating, a number of steps are always passed through each stroke. The starting position is defined as the position in which the bottom table  50  is in its lowermost position. From this position, the bottom table  50  is moved upwards, until it meets a top table (not shown), a base material (not shown) being clamped between the top table and a number of dies (not shown) on the bottom table  50 . During a die-cutting operation, both tables are together moved a short distance upwards, during which movement the pressure exerted on the base material by the dies is increased, until the dies penetrate into the base material and cut products out of the base material. Then, the bottom table  50  together with the dies is moved back downwards, with the die-cut products remaining on the dies. The base material, which is generally in strip form, is moved onwards a certain distance before the next stroke. 
     The removal device  1  is used to pick up the die-cut products from the dies. During this operation, it is of essential importance for the movement of the removal device  1  to be adapted to the movement of the tables of the die-cutting apparatus in such a manner that the extraction head  11  cannot become jammed between the top table and the dies on the bottom table  50 . 
     It is also important for the removal device  1  to remove all the die-cut products at each stroke. Therefore, the die-cutting apparatus is generally provided with a security means which signals if a product has remained in place and which is able to stop the movement of the die-cutting apparatus. This security means, which forms part of the die-cutting apparatus, is not shown in the figures. 
     The movement of the removal device  1  is related to the movement of the bottom table  50 . The structure of the system of rods is such that the extraction head  11  moves towards the tables when the bottom table  50  is moving downwards and moves away from the tables when the bottom table  50  is moving upwards. The diagrammatic representation of the removal device  1  in FIGS. 2 and 4 clearly illustrates this relationship between the movements of the removal device  1  and the bottom table  50 . 
     FIG. 1 shows the removal device  1  in a pick-up position, i.e. the position in which the extraction head  11  is situated above the die-cut products and is picking them up from the dies. The pick-up position is also diagrammatically illustrated in FIG.  2 . In the pick-up position, the bottom table  50  is situated in a low position and the distance between the top table and the dies is such that the extraction head  11  can be moved between the top table and the dies. When the bottom table  50  is moved upwards, this movement, via the second connecting rod  33 , brings about a rotation of the rocker rod  26  about a rotation point  36 . This rotation of the rocker rod  26  and the associated displacement of the first end  25  of the rocker rod  26  results, via the adjustment rod  21  and the first connecting rod  18 , in a linear displacement of the transfer rod  12  which is directed away from the tables. When the transfer rod  12  has been moved away from the tables by a distance which is such that the extraction head.  11  is situated above the collection ends  41  of the discharge chutes  40 , the removal device  1  is in a release position. The release position is shown in FIGS. 3 and 4. 
     In this example, the extraction head  11  moves in a direction which is substantially at right angles to the direction in which the dies move. This is advantageous with a view to utilizing the limited free space which is available in the immediate vicinity of a die-cutting apparatus. 
     In the pick-up position, the extraction head  11  is situated above the die-cut products and is activated in order to pick up the products. In this example, in which the extraction head  11  is an electrically actuable magnet, a magnetic field is generated and, under the influence of the said magnetic field, the products come to bear against the extraction head  11 . During the picking-up operation, the die-cut products substantially retain their positions with respect to one another. 
     During the movement from the pick-up position to the release position, the magnet remains in an operative state. In the release position, the magnet is brought into an inoperative state, so that the die-cut products drop off the magnet. In the release position, the magnet is situated above the collection ends  41  of the discharge chutes  40 , so that die-cut products are collected by the said collection ends  41 . 
     The magnet can be actuated by means of activating means which are already being used to activate the die-cutting apparatus. Another possibility is for the magnet to be actuated with the aid of a switch which is arranged in the guide  14  and is actuated by the transfer rod  12 . 
     The discharge chutes  40  can be omitted if the die-cut products, after they have been released by the extraction head  11 , can remain at the location where they are collected and do not need to be moved any further. 
     In this example, the removal device comprises a system of rods which is secured at a fixed rotation point  36  and converts a movement of the dies into a movement of the extraction head  11 . As a result, a movement of the extraction head  11  is activated mechanically on the basis of a movement of the dies. The activation could also be produced by electronic means, for example. However, mechanical activation is advantageous since activation of this type is relatively unsusceptible to faults. Moreover, a removal device in which the activation takes place by mechanical means can easily be used for different types of die-cutting apparatus, irrespective of the movement characteristics of the dies. 
     It will be clear to the person skilled in the art that the scope of the present invention is not limited to the embodiment discussed above, but rather numerous amendments and modifications to this embodiment are possible without departing from the scope of the invention as defined in the appended claims. 
     For example, the extraction head  11  could be provided with pneumatically actuable suction cups, which are known per se, for picking up the die-cut products and releasing them again, instead of the electrically actuable magnet described above. 
     Another possibility is for the removal device  1  not to be equipped with a system of rods, but rather with a cam system which provides direct activation of the movement of the extraction head  11  on the basis of the movement of the bottom table  50  of the die-cutting apparatus. 
     The movement of the extraction head  11  has to be accurately matched to the movement of the tables of a die-cutting apparatus. In the above text, the removal device  1  has been described in connection with a die-cutting apparatus in which the bottom table  50  undergoes most of the displacement and the top table only undergoes a slight displacement during the die-cutting operation, movements of the removal device  1  being related to movements of the bottom table  50 . The removal device  1  can also be used for other types of die-cutting apparatus, for example die-cutting apparatus in which the top table undergoes most of the movement. In die-cutting apparatus of this type, the removal device  1  may be installed in such a manner that movements of the removal device  1  are related to movements of the top table. 
     In the above text, the removal device  1  has been described as mounted on a die-cutting apparatus, but this does not detract from the fact that the removal device  1  in the unmounted state is also covered by the scope of the invention.