Abstract:
A device for comminuting a residual sheet metal grid includes a grid supply system defining a grid supply plane and supplying the grid in a longitudinal direction; and a cutting assembly including a plurality of shearing teeth extending along a transverse direction transverse to the longitudinal direction. The shearing teeth can include a cutting edge, a cutting edge portion, or both a cutting edge and a cutting edge portion. The cutting assembly can be constructed and arranged to cut the metal grid along the longitudinal direction and the transverse direction.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to German Utility Model Application DE 20 2004 016 214.8, filed on Oct. 20, 2004, the entire contents of which are hereby incorporated by reference. 
     TECHNICAL FIELD 
     The description relates to a residual grid cutting device for comminuting residual sheet metal grids which have been processed with sheet metal processing machines. 
     BACKGROUND 
     Specific geometric shapes are cut out by means of a laser or stamped out by stamps from large metal sheets by sheet metal processing machines. A residual sheet metal grid is left over as a waste product requiring disposal. The residual sheet metal grid can be removed from the sheet metal processing machine manually or automatically and discarded in a container in a complete or folded state. However, residual sheet metal grids of this type are generally large and unwieldy. This impairs the production operation because wide transport paths are necessary, the process reliability may suffer and the space inside the container is not fully used. Therefore, it has already been proposed to stamp or cut up the residual grids, for example, with a laser machine. Whilst the laser machine cuts up the residual sheet metal grids, it is not available for processing the sheet metal. The comminution of the residual sheet metal grids therefore impedes optimum use of the laser machine for processing sheet metal. 
     As an alternative, it has been proposed to break down the residual sheet metal grids into strips by means of a guillotine shears following the production of the parts. However, those strips still have the same width as the original residual sheet metal grids. Handling such strips remains difficult. Furthermore, containers are not properly used. 
     SUMMARY 
     According to one aspect, a device for cutting up residual sheet metal grids includes a cutting mechanism which has, transversely to the residual grid supply direction, a plurality of shearing teeth which are constructed and arranged in such a manner that the residual sheet metal grids are cut into pieces both in relation to the residual grid width and in relation to the residual grid length. With a residual grid cutting device of this type, planar residual sheet metal grids or residual sheet metal grids having slight deformations which are produced during processing on stamping or laser machines can be cut up into small pieces. The number of pieces relative to the residual grid width can be determined by the number of shearing teeth. The residual grid pieces obtained in this manner can be of a size that allows optimum use of the space in a container. The residual grid cutting device can be operated in isolation or can be arranged downstream of a sheet metal processing machine and consequently be linked thereto. Long transport paths can thereby be prevented and the residual sheet metal grids can be comminuted by the residual grid cutting device directly after being processed by the sheet metal processing machine. 
     In one embodiment, at least one cutting edge or one cutting edge portion of a shearing tooth can be orientated in such a manner that it comes into engagement with the residual sheet metal grid, during a cutting operation, first by means of a first end and then by means of a second end. This means that cutting is carried out by the shearing teeth, not stamping. The cutting edge comes into contact with the residual sheet metal grid only gradually during the cutting operation. Less force is thereby required in order to comminute the residual sheet metal grid. Consequently, the residual grid cutting device can be operated so as to optimize the forces applied. For example, a configuration of the cutting edge is also possible in which the cutting edge has two cutting edge portions which are orientated obliquely relative to the residual grid supply plane and together form a tip which comes into engagement first with the residual sheet metal grid. The ends of the cutting edge portions remote from the tip come into engagement with the residual sheet metal grid later. 
     It is possible to bring about engagement of the cutting edge in the residual sheet metal grid, which engagement continues with the cutting movement, if at least one cutting edge of a shearing tooth is orientated obliquely relative to the residual grid supply plane. This means that the engagement of the cutting edge in the residual sheet metal grid extends during the cutting movement from one end of the cutting edge to the other end of the cutting edge. 
     In one embodiment, the shearing teeth have at least one cutting edge which is orientated transversely to the residual grid supply direction. The cutting edge can form an angle α in the range 0&lt;α≦90° relative to the residual grid supply direction. The orientation of the cutting edge determines the shape of the residual grid pieces into which the residual sheet metal grid is comminuted. If a first cutting edge of a cutting tooth is orientated perpendicularly to the residual grid supply direction, another cutting edge can be orientated parallel with the residual grid supply direction so that rectangular residual grid pieces are cut out. It is also possible to orientate a cutting edge parallel with the residual grid supply direction and to orientate a second cutting edge at an angle in the order of 0&lt;α≦90° relative to the residual grid supply direction so that a saw-toothlike cutting edge is produced. 
     In some constructions, the cutting teeth have two cutting edges which are orientated transversely to the residual grid supply direction. The cutting edges preferably converge at a tip. 
     In such an orientation of the cutting edges, a saw-toothlike contour can be obtained. Depending on the construction of the shape of the saw teeth, lateral movement of the residual sheet metal grid or the cutting mechanism may be necessary in order to ensure that not only zig-zag-like strips, but also pieces which are actually smaller are sheared off and splitting of the residual sheet metal grid is brought about relative to the width thereof. 
     In a particularly preferred configuration, it may be provided that the cutting edges of a shearing tooth are of different lengths. This means that an asymmetrical saw-tooth shape is produced. With a saw-tooth shape of this type, lateral movement of the residual sheet metal grid or the cutting mechanism is not necessary in order to bring about comminution in the longitudinal and transverse direction of the residual sheet metal grid. 
     The cutting mechanism is preferably in the form of a step type shearing device which has, transversely to the residual grid supply direction, a plurality of shearing teeth which can be driven by at least one stroke device and which can be moved past a support face for the residual sheet metal grid. 
     The contour of the support face is advantageously adapted to the contour of the shearing teeth. Variable possible uses result when a stroke device is provided for each shearing tooth. This means that the cutting teeth can be moved individually, in particular individually one after the other, in the case of relatively thick residual sheet metal grids in order to comminute the residual sheet metal grid into individual pieces. By the stroke devices being controlled in a suitable manner, however, the shearing teeth can also be moved simultaneously if, for example, relatively thin metal sheets have to be comminuted. Shearing teeth of the same type can be arranged on the individual stroke devices, in particular shearing teeth which have the same dimensions. 
     In some embodiments, the device includes a shearing tooth holder, on which the shearing teeth are arranged and which can be driven by at least one stroke device. This means that the shearing teeth are moved together irrespective of the thickness of the residual sheet metal grid. It is advantageous for the shearing teeth to have different heights. The stroke device must therefore apply smaller forces for shearing off the residual grid pieces. The shearing teeth do not all have to be moved simultaneously through the metal sheet. 
     If the cutting mechanism is in the form of a step type shearing device, the residual grid is not automatically drawn in. Therefore, it is advantageous for the residual grid supply system to be in the form of a drivable residual grid transport device. 
     In a preferred configuration, it is provided that the residual grid cutting device is operated in a clocked manner and the advance of the residual grid transport device is adapted to the size, in particular the depth, of the shearing teeth or a stop which limits the advance is provided for the residual sheet metal grid. During clocked operation, the residual sheet metal grid is moved forwards between two strokes of the shearing teeth. The forward movement is of such a magnitude that not only are strips separated from the residual sheet metal grid, but also the strips further broken down into smaller pieces. It may be necessary for cutting edges produced in a first cutting operation to be crossed by the cutting edges of the cutting teeth in a second cutting operation. As an alternative or in addition, at least one stop may be provided for the residual sheet metal grid and determines the extent to which the residual sheet metal grid is moved under the shearing teeth. 
     The advance or the position of the stop can be adjusted in such a manner that an overlapping cut is produced. The at least one stop can be arranged on a shearing tooth. In particular, each shearing tooth can have a stop. 
     Consequently, the stop can be moved with the shearing tooth. The shearing teeth can be moved so far upwards that the residual sheet metal grid can be moved completely under the cutting teeth, if necessary. If the shearing teeth are changed in order to obtain a different cutting geometry, the stop is also automatically changed. The advance is thereby always correctly adjusted to the shearing tooth depth of the shearing tooth currently being used. 
     In some other implementations, the shearing teeth are arranged on mutually opposite shearing tooth holders. It is particularly preferable for the shearing tooth holders to be in the form of rotatable shafts. This means that the residual sheet metal grids can be separated into identical pieces in a rotary cutting operation. The shearing teeth can be arranged on the shearing tooth holders in such a manner that the shearing teeth draw in the residual sheet metal grid during cutting. Therefore, the residual grid supply system does not have to be drivable. It is also advantageous in this configuration for the cutting edges of the shearing teeth not to engage simultaneously in the residual sheet metal grid over the length of the cutting edges thereof. In that manner, cutting is brought about instead of the metal sheet being stamped. The shearing teeth can be arranged in such a manner that the metal sheet is not completely cut, but instead is partially deformed. The maximum force occurring is thereby reduced. 
     The shearing teeth are advantageously arranged on cutter wheels which are arranged on a shaft in a rotationally secure manner. The production of the cutting mechanism is thereby simplified. Individual cutter wheels with shearing teeth fitted thereto can further be readily exchanged. 
     The shearing teeth are preferably constructed in a triangular manner and a plurality of rows of shearing teeth are provided in a peripheral direction on a shearing tooth holder, the shearing teeth of rows which are adjacent in a peripheral direction being arranged so as to be offset relative to each other. Owing to the triangular construction of the shearing teeth, it is possible for them first to be introduced into the metal sheet by means of a shearing tip. 
     Consequently, the force necessary is reduced. Owing to the geometry of the shearing teeth, it is possible to adjust the cutting gap by adjusting the spacing of the axes of the shafts. The fact that the shearing teeth are arranged so as to be offset relative to each other ensures that the metal sheet is split into pieces. 
     It is particularly preferable for the shearing teeth of a first shearing tooth holder to delimit free spaces whose contours are adapted to the contours of the shearing teeth of a second shaft. This means that the shearing teeth of the various shearing tooth holders are offset relative to each other by a half pitch. Complete separation of the residual sheet metal grid is thereby ensured. 
     According to some aspects, a sheet metal processing unit includes a sheet metal processing machine and a residual grid cutting device. This means that the residual grid cutting device can be linked to a sheet metal processing machine and the comminution of the residual sheet metal grids can be brought about directly after the sheet metal is processed. The residual sheet metal grids do not have to be intermediately stored, which is possible in principle, however, if the residual grid comminution device is operated in isolation. 
     In a preferred configuration, there may be provision for a transport device to be provided for transporting the residual sheet metal grids from the sheet metal processing machine to the residual grid supply system. Consequently, it is ensured that the processed residual sheet metal grids are removed from the sheet metal processing machine and are correctly supplied to the residual grid cutting device. 
     A sorting device can be associated with, in particular integrated in, the residual grid cutting device. Consequently, sorting of the residual pieces in accordance with the type of material can be carried out and those pieces can be conveyed to separate collection containers. 
     The sorting is thereby effected directly after the residual sheet metal grids are cut up so that the sheet metal pieces do not have to be sorted at a later point in time. 
     Other features will be apparent from the description, the drawings and the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective top view of a residual grid cutting device. 
         FIG. 2  shows the cutting mechanism of the residual grid cutting device of  FIG. 1 . 
         FIG. 3  is a cross-section through the residual grid cutting device. 
         FIG. 4   a  is a schematic illustration of four shearing teeth each having a stroke device. 
         FIG. 4   b  is a schematic illustration of four shearing teeth having a common shearing tooth holder. 
         FIG. 5  is a side view of a sheet metal processing unit. 
         FIG. 6  shows part of a cutting mechanism of a residual grid cutting device. 
         FIG. 7  shows a cutter wheel of the arrangement according to  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , a residual grid cutting device  1  includes a cutting mechanism  2  which has a plurality of shearing teeth  4  transversely to the residual grid supply direction  3 . A residual sheet metal grid  6  is supplied to the cutting mechanism  2  by means of a residual grid supply system  5 . The residual sheet metal grid  6  is located in the residual grid supply plane. The residual grid supply system  5  is in the form of a residual grid transport device which can be driven and consequently can move the residual sheet metal grid  6  against at least one stop  7 . The stops  7  are arranged on the shearing teeth  4  in the embodiment and are also moved therewith. When the residual sheet metal grid  6  strikes the stop  7 , the residual sheet metal grid  6  is supported on a support face  8  whose contour is adapted to the shearing teeth  4 . In some embodiments, a stroke device  9  is associated with each shearing tooth  4  in the embodiment. The stroke devices  9  are arranged in a carrier  10  which also acts as a cover. In some embodiments, the shearing teeth  4  can be caused to carry out a stroke movement by means of the stroke devices  9  and moved past the saw-toothlike edge of the support face  8 . 
     In the case of a stroke movement downwards, the cutting edges  11 ,  12  of the teeth  4  engage in the residual sheet metal grid  6 . In this instance, it should be noted that the cutting edges  11 ,  12  are arranged obliquely relative to the residual grid supply plane. This means that the cutting edges  11 ,  12  first come into contact with the residual sheet metal grid  6  at one end  13 ,  14  and, in the case of further stroke movement downwards, the cutting edges  11 ,  12  come  11  into engagement in a continuous manner with the residual sheet metal grid  6  over the length thereof as far as the ends  15 ,  16 . This means that the cutting edges  11 ,  12  are constructed so as to be angled for shearing. Therefore, the shearing teeth  4  carry out a cutting movement. During the cutting movement, the shearing teeth  4  are moved past the edge of the support face  8 . The support face  8  therefore forms an abutment for the residual sheet metal grid  6 . The cutting edges  11 ,  12  are constructed so as to be of different lengths, the cutting edge  11  being orientated obliquely relative to the residual grid supply direction  3 . 
     Owing to the arrangement of the cutting edges  11 ,  12  relative to each other, parallelograms are cut out in the embodiment. Therefore, the residual sheet metal grid  6  is divided up into regular parallelograms. 
       FIG. 3  is a cross-section through the cutting mechanism  2 . It is clearly visible that the cutting edge  12  is also constructed so as to be angled for shearing. The shearing tooth  4  is moved downwards and raised by the stroke device  9 . A control unit  17  is arranged in the rear portion of the cutting mechanism  2 . 
       FIG. 4   a  shows an arrangement of shearing teeth  4  with each including a respective stroke device  9 . Therefore, they can be moved individually or together. They are preferably moved individually in order to cut relatively thick residual sheet metal grids. They may be moved together in order to cut relatively thin metal sheets. The cutting edges  11  are arranged obliquely relative to the residual grid supply plane. All the shearing teeth  4  are of the same height H. 
     According to another embodiment depicted in  FIG. 4   b , the shearing teeth  4   a  to  4   d  are arranged on a common cutting tooth holder  20 . The holder  20  is connected to two stroke devices  9 . Therefore, the shearing teeth  4   a  to  4   d  are moved together. Metal sheets of different thicknesses are still comminuted by a common movement of the shearing teeth  4   a  to  4   d . In order better to distribute the force which has to be applied by the stroke devices  9 , the shearing teeth  4   a  to  4   c  have different heights HI to H 3  so that first the tip of the shearing tooth  4   c  comes into engagement with the residual sheet metal grid, and subsequently the cutting edge lie gradually comes into engagement with the residual sheet metal grid. Subsequently, the tip of the shearing tooth  4   b  and then the cutting edge lib gradually come into engagement with the residual sheet metal grid. Subsequently, the tips of the teeth  4   a  and  4   d  engage in the residual sheet metal grid and the cutting edges  11   a  and lid subsequently cut the residual sheet metal grid. 
       FIG. 5  is a side view of a sheet metal processing unit  25 . The sheet metal processing unit  25  comprises a sheet metal processing machine  26  which comprises a table  27  for transporting metal sheets or residual sheet metal grids. A residual grid cutting device  1  is coupled therewith, the residual grid supply system  5  being arranged in a plane below the table  27 . A transport device  28  is provided in order to place residual sheet metal grids from the table  27  on the residual grid supply system  5 . The residual sheet metal grids are supplied to the cutting mechanism  2  by means of the residual grid supply system  5 . 
     An alternative configuration of a cutting mechanism  30  is illustrated in  FIG. 6 . The cutting mechanism  30  comprises a plurality of shearing teeth  31 ,  32  which are arranged on  13  shearing tooth holders  33 ,  34  which are in the form of rotatable shafts. The rotatable shearing tooth holders  33 ,  34  are coupled for movement by means of gears  35 ,  36 . The shearing teeth  31 ,  32  of the various shearing tooth holders  33 ,  34  are constructed so as to be different. The shearing teeth  31  are constructed in a substantially triangular manner, whereas the shearing teeth  32  have a notch  37 . The shearing teeth  31 ,  32  are each arranged in rows on the shearing tooth holders  33 ,  34 , the shearing teeth  31 ,  32  of rows which are adjacent in a peripheral direction being arranged so as to be offset relative to each other. The shearing teeth  31  of adjacent rows further overlap each other slightly. 
     Four shearing teeth  32  delimit a free space  38 , the contour of the free space  38  being adapted to the shearing teeth  31 . Accordingly, four shearing teeth  31  form a free space  43  which can receive a shearing tooth  32 . Since the shearing teeth  31 ,  32  are arranged on rotatable shafts, the cutting edges  39 ,  40 ,  41 ,  42  of the shearing teeth  31 ,  32  come into engagement with the residual sheet metal grid not by means of the entire length thereof simultaneously, but instead gradually with a continuous cutting movement. 
       FIG. 7  shows a cutter wheel  45 , on which a plurality of shearing teeth  31  are arranged. In particular, they are screwed to the cutter wheel  45 . In that manner, the shearing teeth  31  can be changed relatively readily. The cutter wheel  45  has tappets  46  so that it can be arranged on a shaft in a rotationally secure manner. Since the cutter wheel  45  can be fitted to a shaft, it can readily be changed. 
     Other implementations are within the scope of the following claims.