Abstract:
A device for cutting tubular and rod-shaped work pieces using the whirling method includes a whirling unit on which a holder mounted so as to rotate, connected with a drive, for a saw blade having internal teeth is disposed. The holder and saw blade are provided with corresponding reference mechanisms for fixation of the saw blade in a defined position. The device also includes a mechanism for automatic replacement of the saw blade. A saw blade having internal teeth is also provided for use in this device. The saw blade has at least two indexing bores and at least two gripping openings, which are disposed offset relative to one another.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Applicants claim priority under 35 U.S.C. §119 of European Application No. 09013935 filed on Nov. 6, 2009. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a device for cutting tubular and rod-shaped work pieces using the whirling method, including a whirling unit on which a holder mounted so as to rotate, connected with a drive, for a saw blade having internal teeth is disposed, whereby holder and saw blade are provided with corresponding reference means for fixation of the saw blade in a defined position. The invention furthermore relates to a saw blade with internal teeth for use in this device. 
     2. The Prior Art 
     The whirling method is a chip-lifting method in which the tool circles around the work piece in the manner of a spiral whirling. The cutting depth is produced using one or more blades that rotate at a high cutting speed in a single work cycle. In this connection, the inner mantle surface formed by the cutting tool rolls on the cylindrical outer mantle surface of the work piece to be processed. This movement process is superimposed on the constantly circular movement of the cutting tool. 
     The whirling method has the advantage that a great number of cutting tools, particularly separating steels, can be disposed next to one another, and stand in engagement with the work piece over a larger segment region, at the same time. In whirling cutting, a whirling saw tool with internal teeth is used in this connection. The cutting teeth of the whirling tool with internal teeth can penetrate tangentially into the work piece. Because of the whirling method, the effective penetration radius of the whirling tool has to cover only the wall thickness of the work piece. If this work piece is a solid material, the whirling tool has to penetrate only to the center point of the solid material because the other half of the work piece is cut off by means of the circular movement of the whirling tool. 
     Use of the whirling method for cutting tubular and rod-shaped work pieces has proven itself; in particular, in this connection, the processing times can be clearly reduced. Replacement of the saw blade with internal teeth, however, proves to be time-consuming because the heavy saw blades have to be removed from the tool holder and clamped into it by hand. This procedure is all the more complicated if the saw blade has a high temperature due to a cutting process that took place within a short period of time. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a remedy for these disadvantages. The invention is based on the task of providing a device of the type previously stated, which allows time-optimized replacement of the saw blade, even at a high saw blade temperature. According to the invention, this task is accomplished by a device for cutting tubular and rod-shaped work pieces using the whirling method having a means for automatic replacement of the saw blade. 
     With the invention, a device for cutting tubular and rod-shaped work pieces using the whirling method is provided, which allows time-optimized replacement of the saw blade even at high saw blade temperatures. Hereinafter, the term “saw blade” subsumes all ring-shaped tools with internal teeth that are suitable for cutting tubular and rod-shaped work pieces. This term also includes, for example, milling tools configured in ring shape. 
     In a further aspect of the invention, the whirling unit is disposed within a unit portal, whereby another support portal is disposed parallel to the unit portal, and connected with the unit portal by way of at least one rail. A change-over device is mounted on the at least one rail so as to be displaced via a drive. In this way, a precise, defined linear displacement of the changeover device within a rigidly connected support system is brought about. Thus, bringing in and removing a saw blade can take place on a defined spatial axis. 
     In an embodiment of the invention, the changeover device has at least one holder for a saw blade that comprises holder fingers that correspond with gripping openings present in the saw blade. In this way, time-optimized, reliable holding of a saw blade is made possible. 
     In another embodiment of the invention, the change-over device has two arms disposed to lie opposite one another. The arms form a holder for a saw blade and at least one holder finger is disposed on the arms in each instance. In this connection, the arms are preferably configured as clamping arms, in such a manner that they are suitable for handling and clamping a work piece to be processed. In this way, a combined pick-up is brought about, which, in the form of an integrated component, not only can perform a tool replacement but also can be used to handle and clamp a work piece to be processed. In this way, the installation space required is clearly reduced. The method steps “handling and clamping the work piece” and “performing a tool replacement” can therefore take place on one and the same linear rail, with one and the same drive. 
     In a further aspect of the invention, the clamping arms are mounted in floating manner and have clamping jaws that can be braced against one another, whereby a fixation mechanism is provided that is set up in such a manner that the clamping arms are locked in place only when the two clamping jaws rest against the work piece. In this way, the risk of incorrect bracing of the work piece when it is clamped in place is counteracted. Slight unevenness of the rod-shaped work piece can therefore be balanced out. 
     It is advantageous if locking takes place mechanically and with shape fit. In this way, a high degree of process safety in clamping the work piece is achieved. 
     In an embodiment of the invention, the holder of the whirling unit comprises indexing pins that correspond with indexing bores present in the saw blade. In this way, automatic fixation of a saw blade brought in by the changeover device, in a defined position, is made possible. Preferably, the indexing pins have bracing elements for a force-fit connection with the saw blade. The bracing elements can preferably be activated pneumatically, hydraulically, or electrically. 
     Alternatively, in place of the indexing pins, indexing bores can, also be disposed in the holder of the whirling unit, which bores correspond with indexing bolts present on the saw blade. In this case, the indexing bores preferably have locking elements for a force-fit and/or shape-fit connection with the indexing bolts of the saw blade. 
     In a further aspect of the invention, the change-over device has a displaceable carriage for bringing in and removing saw blades. At least one holder for a saw blade is disposed on the displaceable carriage. In this connection, it is advantageous if the holder has at least one holding pin that corresponds with a holding opening disposed in the saw blade. In this way, reliable loading and unloading of the changeover device with saw blades is made possible. 
     In an advantageous embodiment of the invention, the carriage is disposed on a telescope rail by way of which it can be moved. In this way, the required construction space is optimized. 
     In an embodiment of the invention, means for positioning the tool holder in a defined rotational position are disposed on the whirling unit. In this way, identical placement of the tool holder during every tool replacement process is made possible, so that no additional position adjustments by means of the changeover device are necessary. 
     In an embodiment of the invention, a handling device for loading and unloading the carriage with saw blades is provided. In this way, fully automatic loading and unloading of the whirling unit with saw blades, without any operating personnel required, is made possible. As a result, a continuous production process is guaranteed. 
     In a further aspect of the invention, the handling device has means for reading tool data out of a data memory disposed on a saw blade. In this way, fully automatic selection of a suitable saw blade is made possible, against the background of the work piece to be processed. 
     The invention is furthermore based on the task of providing a saw blade for use in a device for cutting tubular and rod-shaped work pieces, which blade allows time-optimized saw blade replacement even at high tool temperatures. According to the invention, this task is accomplished by a saw blade with internal teeth wherein at least one indexing bore or at least one indexing bolt and at least two gripping openings are present, which are disposed offset relative to one another. 
     In a further aspect of the invention, at least one holding opening is provided, which is disposed offset relative to the gripping openings and the indexing bores. This holding opening allows fixation of the saw blade on the carriage for providing material to the changeover device. A locking bolt of the carriage can be guided by means of the at least one holding opening. In this way, the saw blade is fixed in place on the carriage. The gripping openings required for holding the saw blade on the changeover device are not obstructed in this way. 
     In a further embodiment of the invention, means for storing tool data in memory are provided. In this way, identification of a saw blade required for the cutting process is made possible. The means for storage in memory can be not only tactile but also optical (bar code) or electronic (RFID chip) data carriers. For reading out the data, a corresponding reader is simply disposed on the handling device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention. 
       In the drawings, 
         FIG. 1  is a schematic representation of a whirling cutting device in a view from the rear; 
         FIG. 2  shows the device from  FIG. 1  in a spatial representation; 
         FIG. 3  is a detailed view of the pick-up of the device from  FIG. 1 ; 
         FIG. 4  is a detailed representation of the carriage of the device from  FIG. 1 ; 
         FIG. 5  shows the tool holder of the whirling unit of the device from  FIG. 1 ; 
         FIG. 6  shows a saw blade for use in the device from  FIG. 1 ; 
         FIG. 7  shows another embodiment of a tool holder of the whirling unit; and 
         FIG. 8  shows another embodiment of a saw blade for use in the tool holder according to  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The whirling cutting device selected as an exemplary embodiment comprises a whirling unit  1  having a work piece clamping device  11  as well as a pick-up  2 , which are disposed in a frame system  3 . In this connection, frame system  3  is essentially formed from two portals  31 ,  32  that are disposed parallel to one another and are connected with one another, on the head side, by way of a connection beam  33 . In this connection, the whirling unit is attached to the unit portal  31 ; the support portal  32  serves for the bearing of connection beam  33 . A rail  34  is attached to connection beam  33 , on which rail pick-up  2  is disposed in displaceable manner. 
     Whirling unit  1  comprises a tool holder  12  that is connected with a drive—not shown. The drive has an angle generator that allows precise positioning of the tool holder. Tool holder  12  is connected with a cross table arrangement by means of which it can be moved on defined curves, by way of a control. 
     Tool holder  12  is essentially drum-like and configured to be conical, for removal of chips. In tool holder  12 , around its circular opening, a contact flange  13  is disposed, for precision-fit contact of a saw blade  4 . For centering saw blade  4  in tool holder  12 , contact flange  13  is provided circumferentially with a bevel—not shown—which corresponds with a corresponding bevel  42  of the blade carrier ring  41  of saw blade  4 . On the circumference, four indexing pins  14  are disposed on contact flange  13 , offset by 90 degrees relative to one another, in each instance, which pins engage into corresponding indexing bores  43  of saw blade  4 . Indexing pins  14  have bracing elements  141  activated by spring pressure, by way of which elements saw blade  4  can be braced in tool holder  12 . Offset by 45 degrees relative to indexing pins  14 , in each instance, four t-nuts  15  are affixed to the circumference of contact flange  13 . T-nuts  15  engage into corresponding indentations  44  of blade carrier ring  41  of saw blade  4 . T-nuts  15  serve for torque transfer and for centering of saw blade  4 . A gear mechanism  16  for accommodating a drive belt—not shown—is disposed on the circumference of the drum-shaped tool holder  12 . 
     Pick-up  2  surrounds two clamping arms  21  that are disposed in a housing  20 , lying opposite one another, and can be moved in opposite directions, centered relative to the work piece diameter, by way of a clamping drive  22 . Clamping jaws  210  that can be braced against one another are disposed on clamping arms  21 . Housing  20  is mounted to float on a drive flange  201 , by way of which pick-up  2  can be moved along the rails  34  of connection beam  33 . This floating mounting can be fixed in place by way of a mechanical locking mechanism—not shown. A rod-shaped work piece to be processed can be clamped between clamping jaws  210 , whereby when the two clamping jaws  210  lie against the work piece, the position of the pick-up housing  20  is fixed in place by way of clamping elements of the mechanical locking mechanism. Clamping jaws  210  can be moved toward one another by way of a servo-controlled clamping drive  22 . Different clamping forces can be set by way of the servo-controlled clamping drive, so that thin-walled pipe sections can be clamped without being irreversibly deformed. 
     On their side facing whirling unit  1 , holders  23  are disposed on clamping jaws  210 , which hold two pneumatic cylinders  24  that lie opposite one another, in each instance. By way of pneumatic cylinders  24 , holding fingers  241  can be moved to pass through gripping openings made in saw blade  4 . In this way, fixation of saw blade  4  on holders  23 , in the correct position, is brought about. 
     Pick-up  2  is displaceably mounted on rails  34  of connection beam  33  of frame system  3  by way of pick-up housing  20 . The movement along rails  34  takes place by way of a spindle axle  35  disposed on connection beam  33 , which axle is connected with a spindle drive  36  and guided by means of the drive flange  201 . 
     Loading holders  23  of pick-up  2  with saw blades  4  takes place by way of a change-over carriage  5  that is attached to support portal  32  of frame system  3 . In the exemplary embodiment, change-over carriage  5  has two tool holders  51 , whereby one of the tool holders  51  serves to hold the new saw blade, and the other tool holder  51  serves to hold the removed saw blade  4 . Change-over carriage  5  is connected with a telescope guide  52  by way of which it can be moved by means of a slide chain drive  53 . For an exact transfer position, the change-over carriage can be mechanically locked in place in defined positions, in each instance. The positions of the telescope carriages of telescope guide  52 , in each instance, are clearly defined by way of built-in braking units—not shown. In  FIG. 4 , change-over carriage  5  is shown with telescope guide  52  completely extended. 
     Tool holder  51  comprises a contact flange  510  that describes an arc, which covers 135 degrees of blade carrier ring  41  of a saw blade  4  in the exemplary embodiment. At its opposite ends, two holding bolts  511  are formed onto the contact flange  510 , lying opposite one another, which bolts correspond with holding openings  46  disposed in blade carrier ring  41  of saw blade  4 . An indexing pin  512  is disposed centered between holding bolts  511  on contact flange  510 . Indexing pin  512  engages into an indexing bore  43  of saw blade  4 , and thereby guarantees that saw blade  4  is held in the proper position. 
     For providing material to the tool carriage  5 , in the exemplary embodiment a supply wagon  6  is provided, on which saw blades  4  are kept available and replaced saw blades can be deposited. Loading and unloading of change-over carriage  5  takes place manually in the exemplary embodiment. A handling device can also be provided, however, which takes over loading and unloading of change-over carriage  5 . When different saw blades  4  are used, these blades can be equipped with a data carrier in which the essential tool data are stored. These data can then be read by way of a reader disposed on the handling unit, thereby making it possible to identify different saw blades. Identification of the different saw blades can also take place by way of combinations of switches disposed on change-over carriage  5 . By means of specific recesses in the saw blades  4 , different switch combinations assigned to the saw blade type, in each instance, are addressed in this connection. 
     To optimize the tool replacement, in the exemplary embodiment, a saw blade  4  is used, which consists of four inserts  40  disposed reciprocally, which are delimited by a blade carrier ring  41 . Blade carrier ring  41  is provided with a bevel  42 , for centered introduction of saw blade  4  into the tool holder  12  of whirling unit  1 . On the circumference of blade carrier ring  41 , four indexing bores  43  are made, offset from one another by 90 degrees, in each instance, which correspond with indexing pins  14  of whirling unit  1 . An indentation  44  is furthermore made in blade carrier ring  41 , centered between two indexing bores  43 , in each instance, which indentations correspond with t-nuts  25  of tool holder  12  of whirling unit  1 . On both sides of two indexing bores  43  that lie opposite one another, a gripping opening  45  is furthermore made in blade carrier ring  41 , in each instance. Gripping openings  45  serve to allow the holding fingers  241  of holders  23  to pass through, in order to fix saw blade  4  in place on pick-up  2 . Furthermore, two holding openings  46  are made to lie opposite one another, between two opposite gripping openings  45  and two opposite indentations  44 . Holding openings  46  serve to allow the holding bolts  511  of tool holder  51  of change-over carriage  5  to pass through. The different bores and passage openings are disposed in such a manner that obstruction of tool holder  51  of change-over carriage  5  and of holders  23  of pick-up  2  as well as obstruction of this holder  23  with tool holder  12  of whirling unit  1  is precluded. 
     During the course of a tool replacement, first a saw blade  4  is introduced into a tool holder  51  of change-over carriage  5 , which is completely moved out for this purpose. In this connection, the indexing pins  512  as well as the holding bolts  511  pass through the indexing bore  43  and the holding openings  46  of saw blade  4 , respectively. Saw blade  4  is held in tool holder  51  by means of holding bolts  511 . Subsequently, change-over carriage  5  moves in along telescope guide  52  to such an extent that saw blade  4  assumes the position required for transfer of saw blade  4  to pick-up  2 . Pick-up  2  is moved along rail  34  of frame system  3  in front of saw blade  4 , and the holding fingers  241  are moved through the gripping openings  45  of saw blade  4 . After fixation of saw blade  4  by means of holding fingers  241 , saw blade  4  is released by holding bolts  511  of the change-over carriage. 
     Pick-up  2  now moves along rail  34  of frame system  3 , in front of tool holder  12  of whirling unit  1 , by way of spindle drive  36 , until indexing pins  14  of tool holder  12  pass through indexing bores  43  of saw blade  4 , and blade carrier ring  41  lies against contact flange  13  in tool holder  12 . Bracing elements  141  of indexing pins  14  are now pressed against the indexing bores, under spring pressure, so that saw blade  4  is fixed in place in tool holder  12  of whirling unit  1 . Subsequently, holding fingers  241  are moved out of gripping openings  45  of saw blade  4 , and pick-up  2  is moved out of whirling unit  1 , along rails  34  of connection beam  33 . 
     After the work piece has been passed through whirling unit  1  by means of the work piece feed  11 , for the subsequent cutting process, it is fixed in place between clamping jaws  210  of pick-up  2 . After clamping jaws  210  have been laid against the work piece, the clamping arms are mechanically locked. 
     Subsequent to the cutting process, the cut-off work piece part can be laid down by way of pick-up  2 . Removal of a saw blade from tool holder  12  of whirling unit  1  takes place in the opposite sequence. In this connection, the removed saw blade  4  is laid down in the free tool holder  51 , after corresponding positioning of change-over carriage  5 ; subsequently, change-over carriage  5  is positioned so that a saw blade  4  that was previously laid into the other tool holder  51  can be picked up by pick-up  2 . 
     In the exemplary embodiment according to  FIG. 7 , four indexing bores  17  are disposed on the circumference of contact flange  13  of tool holder  12 , offset by 90 degrees from one another, in each instance, into which corresponding indexing bolts  47  of saw blade  4  engage. Indexing bores  17  have locking elements by way of which indexing bolts  47  of saw blade  4  can be fixed in place in tool holder  12 . 
     Three centering bolts  18  are affixed to the circumference of contact flange  13 , offset by 120 degrees from one another, in each instance. Centering bolts  18  engage into corresponding centering bores  48  of blade carrier ring  41  of saw blade  4 . Centering bolts  18  serve for torque transfer and for centering of saw blade  4 . 
     Although only a few embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.