Abstract:
Disclosed is a gripping system for receiving a processing tool, and to a storage system. These processing tools are used in processing machines or centres in the woodworking industry. Also disclosed is a processing machine with the above-mentioned storage system. This processing machine is used for processing elongate pieces of wood.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a gripping device for holding a cutting tool and a storage system. Such cutting tools are used, for example, in machine tools and machining centers of the woodworking industry. The present invention further relates to a machine tool having the aforesaid storage system. Such a machine tool is used in particular for machining elongated pieces of wood. 
       PRIOR ART 
       [0002]    A wide variety of cutting tools are generally used in the production of wooden window scantlings because different profiles need to be created on these workpieces. In turn this means that a relatively large number of cutting tools or cutting units (hereafter also referred to as “tools”) have to be kept available and must be inserted into a machine tool as required. 
         [0003]    In the prior art, various measures are disclosed for storing tools, and there is a requirement to optimize the tool change times and thus to carry out the preparation time for providing a tool at the same time as machining a workpiece. For this reason, a plurality of converters are usually used between the tool magazine and the tool change spindle. 
         [0004]    Disk-type changers and chain-type changers are well-known as tool magazines. Disk-type changers require a relatively large amount of space due to their size and, while this is not the case with chain-type changers, the manufacturing costs for the chains of the chain-type changer are comparatively high. Depending on the specific requirement of a machine tool, a decision therefore has to be made as to whether a disk-type changer or a chain-type changer will be used. 
         [0005]    For example, DE 10 2012 201 776 A1 is known which shows a disk-type changer for holding cutting tools and/or cutting units for a machining device. The disk-type changer (magazine) comprises a first holding device having a plurality of first holders for cutting tools and/or cutting units, these holders being arranged on a first circumference. In addition, a second holding device with a plurality of second holders is provided, the second holders being arranged on a second circumference which is smaller than the first circumference. The first and second holding devices are arranged in such a manner that the second circumference lies inside the first circumference. 
         [0006]    EP 2 371 481 A1 which shows a tool magazine is also known. During a tool change, a spindle unit is moved into a transfer position and a gripping element of an arm carries out a tool transfer. A slide which removes a tool from the tool magazine and transfers it to a gripping device is used to remove a tool from the tool magazine. The gripping device in turn supplies the relevant tool to the spindle unit. 
       SUBJECT MATTER OF THE INVENTION 
       [0007]    The aim of the present invention is to provide a gripping device with which it is easier and faster to change a cutting tool or cutting unit (“tool”). In addition, according to the present invention, the intention is to design a compact storage system for cutting tools. 
         [0008]    One idea of the present invention is to remove tools from a tool store/tool magazine and to insert them directly into a holder of a machining spindle. Accordingly, the tool is picked up by a gripping device in such a manner that the region (HSK taper) provided for fixing the tool in a holder of a machining spindle is exposed. 
         [0009]    Claim  1  provides a gripping device which achieves at least one or all of the above-mentioned aims. The same applies to claim  9  which provides a storage system, and claim  15  which relates to a method. The features of the dependent claims relate to further preferred embodiments which can each be combined with one of the independent claims or with each other. 
         [0010]    Very fast tool change cycles can be implemented with the gripping device according to the invention. The gripping device can also prepare a tool change parallel to machining which results in a reduction of the non-productive times. In addition, it is possible due to the gripping device to shift from a stationary tool magazine or linear changer to a tool magazine, for example a disk-type changer, which moves with a tool change spindle. The gripping device can also be designed as a shuttle and thus supply tools from a simple, stationary tool magazine. 
         [0011]    A storage system with a tool magazine which has a plurality of levels has the advantage that a large number of tools can be stored compactly and inexpensively. If necessary, different tools can also be picked from different tool magazines. It is possible to reduce the non-productive times in combination with the gripping device previously mentioned. 
         [0012]    The present invention provides a gripping device for picking a tool from a tool magazine and for transferring said tool to a machining unit, in particular a machining spindle. The gripping device comprises: a basic body and a gripping mechanism joined to said basic body, the gripping mechanism being configured to create a force-fit connection to an outer circumference of a tool holder. In addition to the force-fit connection, a form-fit connection can also be created. The outer circumference of a tool holder of the tool is preferably designed to be cylindrical and preferably adjoins the HSK taper. 
         [0013]    In this way it is possible for an HSK taper of a tool to be exposed and the tool can thus be inserted directly into a holder of a machining unit, in particular a machining spindle. The outer circumference of a tool holder is essentially cylindrical and in particular comprises an HSK gripper groove which, among other things, is provided for holding the tool in a tool magazine, in particular in a tool clamp. 
         [0014]    In one embodiment, the gripping mechanism has two gripper jaws which in sections comprise a gripping portion for gripping the outer circumference of a tool holder. The gripper jaws are preferably each pivotable relative to the basic body by means of a rotary axis, or the gripper jaws can be moved towards each other in parallel. According to a modification, the gripper jaws can have a common rotary axis. 
         [0015]    The gripper jaws can have a first cut-out for a support pin and/or an alignment region for a entrainer pin which is preferably designed as a cut-out. The alignment region is preferably provided on an end portion of the gripper jaws. It is possible to align the tool via the entrainer pin. 
         [0016]    The gripper jaws have a reduced thickness in the region of an end portion. In this way, a collision with the holding disk (disk-type changer) or holding devices of a chain-type changer can be prevented. 
         [0017]    In one embodiment, the gripping mechanism can have a support element which is fixed to the basic body or is formed integrally with the basic body, said support element having in sections a protrusion. This protrusion is preferably formed in such a manner that it may intrude into an HSK gripper groove and in this way prevents the tool from tilting. In particular, the protrusion is formed in sections along a circumference and intrudes into an HSK gripper groove in a circumferential portion or the protrusion is a pin (pressure element) which intrudes into a hole on the tool. The protrusion can be rigid or flexible. 
         [0018]    In a further aspect, a possibly horizontal hole can be provided in the tool holder and the tool can be moved via a pin that is inserted or pushed through. 
         [0019]    The present invention further relates to a storage system for cutting tools, comprising a tool magazine with a plurality of levels, in particular a disk-type tool magazine with a plurality of holding disks, and at least one gripping device which is movable relative to the tool magazine along a preferred vertical guide. Due to the arrangement of a plurality of levels, the tool magazine and therefore also the storage system can be of a very compact design. Thus it is possible to integrate the storage system in a machine tool. Due to the individual features described above, the said gripping device can be constructed in particular according to claim  1 . 
         [0020]    A tool is held on or in a tool clamp of the tool magazine, the tool clamp preferably being provided on a holding disk. As a result, the tool is held in the tool magazine, or is held clamped. 
         [0021]    The gripping device can further be configured to create a force-fit connection or a force-fit and form-fit connection to an outer circumference of a tool holder of a tool. In this version, the tool can be released from a tool clamp by providing a force-fit connection. 
         [0022]    The levels of the tool magazine, preferably the plurality of holding disks of the disk-type tool magazine, are preferably independently movable, in particular rotatable. Thus, for example, it is possible to manually remove a tool while simultaneously operating a different level of the tool magazine. 
         [0023]    In a further version, a rotating mechanism is provided which is configured to rotate the at least one, preferably two, gripping devices about a vertical axis. In this way, the non-productive times can be further shortened. The rotating mechanism is preferably mounted on a second slide movable in the horizontal direction. 
         [0024]    Moreover, a machine tool with a storage system is provided. The storage system is integrated in the machine tool and comprises a tool magazine with a plurality of levels, in particular a disk-type tool magazine with a plurality of holding disks. 
         [0025]    A method for transferring a tool to a machining unit, in particular a machining spindle, comprises the following steps: At least force-fit or force- and form-fit gripping of a tool with a gripping device on an outer circumference of a tool holder of the tool, removal of the tool from a tool magazine, in particular from a tool clamp of a holding disk, and transfer of the tool from the gripping device into a holder of a machining unit, in particular a machining spindle. 
         [0026]    In this way, the tool can be transferred directly into the machining unit from the tool magazine by means of the gripping device, especially as the HSK taper protrudes relative to said gripping device, once the gripping device creates a force-fit or force- and form-fit connection to the tool on a circumference of the tool holder. 
         [0027]    The method is preferably carried out using the previously described gripping device or machine tool and the previously described storage system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is a perspective view of a gripping device according to an embodiment of the present invention. 
           [0029]      FIG. 2  shows the gripping device illustrated in  FIG. 1  before picking up a tool. 
           [0030]      FIG. 3  is a view corresponding to  FIG. 2  seen from a different viewing direction. 
           [0031]      FIG. 4  shows a tool gripped with the gripping device before the transfer into a machining spindle. 
           [0032]      FIG. 5  shows a tool gripped with the gripping device. 
           [0033]      FIG. 6  shows the gripping device during the transfer of a tool from a holding disk of a tool magazine. 
           [0034]      FIG. 7  shows a tool magazine with a plurality of adjacently arranged, disk-shaped holding disks. 
           [0035]      FIG. 8  shows a plurality of adjacently arranged tool magazines with a plurality of holding disks. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0036]    Embodiments of the present invention will be described in detail in the following. Further modifications of certain individual features referred to in this context can each be combined with one another to form new embodiments. 
         [0037]      FIG. 1  shows an embodiment of a gripping device  10  according to the invention. The gripping device  10  comprises a basic body  11  which is provided with compressed air connections  12 . A medium for the operation of gripper jaws  13  is supplied through the compressed air connections  12  as a result of which the gripper jaws  13  of the gripping device  10  can be opened and closed pneumatically. 
         [0038]    In the present embodiment, the basic body  11  comprises compressed air connections  12  which operate a pneumatic mechanism for pivoting the gripper jaws  13 . In an alternative embodiment, the gripper jaws  13  can also be operated hydraulically. It is also possible in further versions to provide an electric motor on the basic body  11  which is used for operating the gripper jaws  13 . 
         [0039]    The gripper jaws  13  are each connected to the basic body  11  by means of a pivot joint  14  and in this way are pivotable between an open position ( FIG. 1 ) and a closed position ( FIG. 5 ). 
         [0040]    While in the present embodiment one pivot joint  14  is provided for each of the gripper jaws  13 , according to a modification of the present embodiment the gripper jaws can also be attached to a common pivot joint with a common rotary axis. The gripper jaws can also be designed as parallel grippers. 
         [0041]    A support element  15  which has a contact surface  15   a  for a tool holder of a tool  20  is attached to the basic body  11  between the gripper jaws  13 . The contact surface  15   a  has a radius such that said surface can rest against an outer circumference of a tool holder of the tool  20 . In addition, in the region of the contact surface  15   a , a protrusion  15   b  is provided which intrudes into an HSK gripper groove  23  of the tool  20  when a tool  20  is picked up. 
         [0042]    Although the support element  15  in the present embodiment is formed as a separate component from the basic body, said support element  15  can also be formed integrally with the basic body  11 . The support element  15  is used to support the tool  20  picked up with the gripping device  10  and secure it against tilting. 
         [0043]    Each of the gripper jaws  13  comprises a first cut-out  13   a  which is dimensioned according to a support pin  24   a  of the tool  20  such that the support pin  24   a  can be inserted into the cut-out  13   a.    
         [0044]    Each gripper jaw  13  further comprises a gripping portion  13   c  for a circumference of the tool holder  22  of a tool  20 . A shoulder  13   a  is also provided in this region. The radius of the gripping portion  13   c  corresponds to that of the contact surface  15   a  of the support element  15 . 
         [0045]    A second cut-out  13   d , which is dimensioned according to approximately half the circumference of an entrainer pin  24   b  of a tool  20 , is provided on each of the gripper jaws  13  in an end region of said gripper jaws  13  directed away from the basic body  11 . In this case, the second cut-out  13   d  of the gripper jaws  13  cooperates with that of the second gripper jaw  13  to enclose the corresponding entrainer pin  24   b  at least in sections in the closed state of the gripping device  10 . At the same time, the tips of the gripper jaws  13  do not touch in the present embodiment. 
         [0046]    Each gripper jaw  13  has a reduced thickness starting from the first cut-out  13   a  towards the end region. In this manner, this region of the gripper jaws  13  can be guided via a holding disk  101  of a tool magazine. By contrast, the portion of the gripper jaws  13  directed towards the basic body  11  has a greater thickness in order to impart greater stability to the gripper jaws  13  in the attachment region to the basic body  11  (pivot joints  14 ). Due to the described change in thickness of the gripper jaws  13 , a step  13   e  is formed in order to prevent a collision with the tool magazine, in particular with a holding disk  101 , on removing a tool therefrom. 
         [0047]      FIG. 2  shows a schematic representation of a tool  20  in addition to the gripping device  10  already described. The representation of the tool  20  is kept consciously abstract and only the holding region of the tool  20  is shown in greater detail in the figures and is described below. Purely by way of example, it can be a milling cutter, a saw tool, a drilling tool, etc. or units with a plurality of tools. 
         [0048]    Located in the holding region of the tool  20  is the HSK taper  21  which is used for clamping the tool  20  in a machining spindle  200  (see  FIG. 4 ). The circumference of the tool holder  22 , which comprises an HSK gripper groove  23 , extends adjacent to the HSK taper  21 . 
         [0049]    Support pins  24   a  and an entrainer pin  24   b , arranged separately from each other, are provided in the holding region of the tool  20  adjacent to the HSK taper  21  or the circumference of the tool holder  22 . The support and entrainer pins  24   a ,  24   b  are arranged circumferentially around the HSK holder  21  at an angle of 120° to each other. 
         [0050]    During insertion of the tool  20  into a holder of the machining spindle  200  described later, the entrainer pin  24   b  is connected to said machining spindle and a medium, for example, can be transferred into the tool  20  via the support pin  24   a . The entrainer pin  24   b  is responsible, among other things, for transferring a torque of the unit axle of the machining spindle  200  to an inner portion of the tool  20 . 
         [0051]      FIG. 6  is an illustration which shows a detail of a tool magazine having a holding disk  101 . The holding disk  101  is rotatably supported about a vertically extending shaft which is inserted into a centrally arranged cut-out  102  of said holding disk  101 . 
         [0052]    Holders  103  are provided at equidistant angles to each other on the outer circumference of the holding disk  101 , said holders each comprising tool clamps  104 . Tools (cutting tools or cutting units)  20  can be inserted into each of these holders  103  and be stored there suspended. The tool clamps  104  serve as support for the HSK gripper groove  23  of the tools  20 . 
         [0053]    Purely by way of example,  FIG. 6  shows two tools  20  in corresponding holders  103 . Each holder  103  and the tool clamp  104  attached thereto comprises an indentation  105  directed towards the center of the holding disk  101  into which the entrainer pin  24   b  of a tool  20  is pushed. In this state, the support pins  24   a  of the tools are located outside the holder  103 . 
         [0054]      FIG. 7  shows a first embodiment of a storage system having a tool magazine  100 . The tool magazine  100  comprises a plurality of holding disks  101  (in this specific example, four holding disks) which are joined together via a common support column  120 . In this case, the holding disks  101  are arranged concentrically one above the other. Due to the arrangement of the holding disks  101  in a concentric manner one above the other, it is possible to provide an extremely compact type of construction which can be integrated in a machine tool. 
         [0055]    Although the holding disks  101  can be driven via a common shaft, it is preferable according to the present invention for each holding disk  101  to be decoupled from a drive motor  125 . Alternatively, each holding disk  101  can also have a separate drive. In this way it is possible to move each holding disk  101  individually. This can be used to further shorten the non-productive times. 
         [0056]    The support column  120  of the holding disks  101  is supported relative to a stand  130  which further holds the drive motor  125 . 
         [0057]    Provided adjacent to the tool magazine  100  is a vertically aligned guide  50  which comprises a pair of parallel guide rails  51  running in the vertical direction. A first slide  52  is movable vertically up and down along the guide rails  51 . The first slide  52  for its part has two guide rails  53  running horizontally, along which a second slide  54  is traversably arranged. 
         [0058]    The second slide  54  bears a rotating mechanism  60  which can perform a pivoting movement of two gripping devices  10  about an axis running in the vertical direction. At the same time, the gripping devices  10  are aligned in different directions (in the present example, in opposing directions). 
         [0059]      FIG. 8  illustrates a further embodiment. The embodiment illustrated in  FIG. 8 . differs essentially compared to the embodiment illustrated in  FIG. 7  in that a plurality of magazines  100 ′ are provided which, in the present case, merely comprise two holding disks  101  arranged one above the other. This arrangement can be provided to load a plurality of machining spindles  200  with tools  20  in parallel. 
         [0060]    In the embodiments illustrated in  FIGS. 7 and 8 , it can be seen that the tool magazines  100 ,  100 ′ are not limited to a specific number of holding disks  101  but rather two, three, four or more holding disks  101  can be provided. 
         [0061]    Moreover, it is pointed out that a tool magazine with only one holding disk  101  can be used for the functioning of the gripping device  10 , or alternatively a chain-type changer can also be used. 
         [0062]    In the embodiments configured in  FIGS. 7 and 8 , two gripping devices  10 , which are rotated by means of a common rotating mechanism  60 , are arranged in pairs. However, it is also possible to attach only one gripping device, three gripping devices or four gripping devices to the rotating mechanism  60 . 
         [0063]    According to a further version of the embodiment described above, only one gripper jaw  13  is attached movably to the basic body  11  while a further gripper jaw  13  is fixed to the basic body  11 . 
         [0064]    In a further modification, the gripping device  10  has no pivotable gripper jaw  13 . Rather, a gripping holder, which is formed similarly to a holder  103  of the previously described tool magazine  100 , 100 ′, is provided on the gripping device. According to this version, on picking up a tool  20  from the tool magazine  100 ,  100 ′, the gripping device is traversed into the vicinity of the holder  103  such that a pusher provided on said tool magazine pushes a tool  20  out of the holder  103  into the gripping holder of the gripping device. One or more protrusions (similar to the protrusion  15   b ) intrude during this process into the HSK gripper groove  23  in order to hold the tool  20  during the transfer to a machining spindle  200 . 
         [0065]    In a further modification of the present invention, a pusher is provided in the region of the tool magazine which pushes a tool into a gripping device in such a manner that the gripping device does not need to exert any movement to exert a force for holding the tool. Purely by way of example, spring elements can provide a force-fit connection between a circumferential surface of the tool holder  22  and the gripping device according to this version. 
         [0066]    It can also be provided alternatively or additionally that the gripping device engages in an HSK taper  21  and thus holds or at least secures the tool during the transfer into a machining spindle. Accordingly, during the transfer, the tool can be additionally gripped in the HSK taper or an HSK taper gripper pulls the tool out of the tool clamp in the tool magazine and pushes it into a gripper clamp before the tool is picked up by the machining spindle. The HSK taper is released again when transferred into a holder of a machining spindle. 
         [0067]    Moreover, according to a further aspect, the tool magazine can comprise a pusher which moves a tool out of a holder of the tool magazine such that the tool can be supplied directly to a machining spindle in an extended position of said pusher. 
         [0068]    While, according to the described embodiments and modifications to the tool  20 , entrainer pins  24  are provided, the gripping device  10  described here is not limited to use for tools  20  with entrainer pins  24 . In addition, according to a further version, tools with only one entrainer pin can be transferred. 
         [0069]    The changeover process for replacing a tool  20  is presented as follows. 
         [0070]    First, a holding disk  101  of the tool magazine  100 ,  100 ′ is rotated in such a manner that a holder  103  with a corresponding tool  20 , which is to be supplied to the machining spindle  200 , is pivoted into a transfer position. 
         [0071]    The first slide  52  is traversed vertically along the guide rails  51  of the guide  50  in such a manner that a gripping device  10  reaches a level of the appropriate holding disk  101 . 
         [0072]    Subsequently, the gripping device  10  is traversed along the guide rails  53  by moving the second slide  54  towards the tool  20  to be picked up. 
         [0073]    Once the contact surface  15   a  of the support element  15  touches the circumference of the tool holder  22  and the protrusion  15   b  intrudes into the HSK gripper groove  23 , the gripper jaws  13  of the gripping device  10  are closed and, on closing of the gripper jaws  13 , the gripping portion  13   c  of said gripper jaws  13  rests on the circumference of the tool holder  22  of the tool  20 . At the same time, the support pins  24   a  are enclosed in sections by the first cut-outs  13   a  and the second cut-outs  13   d  of the gripper jaws  13 . The cut-outs  13   d  are used for alignment and touch the entrainer pin  24   b  on closing the gripping device. 
         [0074]    Closing of the gripping device  10  by moving the gripper jaws  13  results in a combination of form-lock and force-lock once the protrusion  15   b  intrudes into the HSK gripper groove 23  and the gripping portions  13   c  (and  15   b ) are resting on an outer circumference of the tool holder  22 . The gripper jaws  13  create a force-fit connection via the gripping portions  13   c.    
         [0075]    Once the gripping device  10  has picked up the tool  20 , as illustrated in  FIG. 6 , the second slide  54  is traversed horizontally and the tool  20  is removed from the holder  103  or pulled from the tool clamp  104  of the tool magazine  100 . 
         [0076]    By means of a subsequent pivoting movement of the rotating mechanism  60 , the gripping device  10 , which has just picked up the tool  20 , is rotated towards a machining spindle  200  whereas the further gripping device  10  also mounted on the rotating mechanism  60  is pivoted towards the tool magazine  10 . Where applicable, a tool which has just been removed from a machining spindle  200  is clamped in this further gripping device  10 . 
         [0077]    By means of a movement in the vertical direction, the tool  20  is transferred to the machining spindle  200 . As the HSK taper  21  is arranged in such a manner that it extends above the gripper jaws  13  of the gripping device  10  (in other words it is exposed in the gripped state of the gripping device), the tool  20  can be clamped in the machining spindle  200  via the HSK taper  21 . 
         [0078]    Subsequently, the gripper jaws  13  are opened and the machining spindle  200  is traversed into a machining region (not illustrated) of the machine tool. 
         [0079]    While the machining spindle  200  carries out a machining process with the inserted tool  20 , the tool  20  picked up in the further gripping device  10  can be transferred to the tool magazine  100 . For this, the second slide  54  is traversed towards the tool magazine  100  and the tool  20  is pushed into a holder  103 . The entrainer pin  24   b  intrudes thereby into the indentation  105 . Subsequently, the gripper jaws  13  are opened and the gripping device  10  is moved away from the tool magazine  100 . The tool is suspended in the holding disk  101  in that the HSK gripper groove  23  intrudes into a corresponding portion of the tool clamp  104 . 
         [0080]    Subsequently, a new tool  20 , for example, which is to be transferred to the machining spindle  200 , can be selected and picked up. During the changeover, the machining spindle  200  carries out a machining process on a workpiece.