Abstract:
A cutting device for rod-shaped workpieces has two actuating levers each in the form of a two-arm pivot lever. The two-arm pivot levers each have a first arm as an actuator and a second arm having a shearing edge. The actuators move the shearing edges relative to one another. The pivot levers each have an end face. The end faces rest against one another in the shearing position. The second arms each have a detachable cutting insert, and the shearing edges are arranged on the cutting inserts. The actuators can be engaged by a drive device for pivoting the actuators in opposite direction relative to one another.

Description:
BACKGROUND OF INVENTION  
         [0001]    1. Field of the Invention.  
           [0002]    The invention relates to a cutting device for workpieces, for example, rods, bolts and the like, in particular, for threaded bolts. The cutting device comprises two shearing edges movable relative to one another and two actuating levers.  
           [0003]    2. Description of the Related Art  
           [0004]    For installing pipelines, in particular, for suspending pipelines, screw-tightened pipe clamps are usually employed that must be positioned by means of threaded rods. Usually, they must be cut to a particular size, sometimes on site. For this purpose, saws, cut-off machines or other special cutting devices are used. When employing saws and cut-off machines, the cut end of the thread is deformed or a burr is generated so that it is possible only with difficulty to screw a nut onto the threaded rod. In the case of special cutting devices, two actuating levers are used that are provided at their free end with a cutting jaw, respectively, for cutting the threaded rod. In this case, there is also a burr or deformation at the end of the thread that makes screwing of a nut onto the thread significantly more difficult. Moreover, such special cutting devices are relatively large.  
         SUMMARY OF INVENTION  
         [0005]    It is an object of the present invention to configure a cutting device of the aforementioned kind such that, while it has a compact configuration, a proper cropping or cutting of the workpieces is possible.  
           [0006]    In accordance with the present invention, this is achieved in that the actuating levers are two-arm pivot levers having a first arm configured as an actuating arm (actuator) and a second arm that is provided with the shearing edge, respectively.  
           [0007]    In the cutting device according to the invention, two-arm pivot levers are used for the shearing action. With the first lever arm (actuating arm) the pivot levers are pivoted relative to one another in the required direction. The second lever arm is provided with the shearing edges for properly separating or cutting the workpiece to the required length. As a result of the two-arm configuration of the pivot levers, the cutting device according to the invention has a compact size. Despite of its compact size, the cutting device is able to perform a clean cut for separating the workpieces. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0008]    [0008]FIG. 1 is a side view of a cutting device according to the invention.  
         [0009]    [0009]FIG. 2 is a section along the line II-II of FIG. 1.  
         [0010]    [0010]FIG. 3 is an illustration corresponding to FIG. 1 of two cutting inserts in the initial position. 
     
    
     DETAILED DESCRIPTION  
       [0011]    The cutting device is designed to cut or crop rods, bolts and the like, particularly, however, threaded rods, very precisely to the required length in a simple way. The cutting device is configured such that no burrs and the like are formed in the area that is cut. This is particularly advantageous for cutting threaded rods because as a result of the precise cutting action the thread is not damaged so that, for example, nuts can be screwed without problem onto the cut-off end of the threaded rod.  
         [0012]    The cutting device has two pivot levers  1 ,  2  that are pivotably supported by means of bolts  4 ,  5  between two brackets  3  extending transversely to the pivot levers  1 ,  2 . The bolts  4 ,  5  connect the brackets  3  with one another and serve as a pivot axis for the two-arm levers  1 ,  2 . The lower actuating arms  6 ,  7  of the pivot levers  1 ,  2  illustrated in FIG. 1 are loaded relative to one another by a pressure spring (not illustrated). The pressure spring is positioned in recesses  8 ,  9  provided in the actuating arms (actuators)  6 ,  7 ; the recesses  8 ,  9  extend perpendicularly to the bolts  4 ,  5 . The pressure spring loads the pivot levers  1 ,  2  such that the upper arms  10 ,  11  of the pivot lever are loaded in a direction toward one another. In the end position illustrated in FIG. 1, the pivot levers  1 ,  2  rest with plane end faces  12 ,  13  areally against one another. At the level of the bolts  4 ,  5  the end faces  12 ,  13  pass into slanted surfaces  14 ,  15  that diverge relative to one another beginning at the end faces  12 ,  13 . The surfaces  14 ,  15  are positioned at an acute angle  16  relative to one another. This angle  16  determines the maximum pivot travel that can be performed by the two pivot levers  1 ,  2  when the actuating arms (actuators)  6 ,  7  are moved in a direction toward one another. As soon as the slanted surfaces  14 ,  15  contact one another, the maximum pivot travel of the pivot levers  1 ,  2  is reached.  
         [0013]    The end faces  12 ,  13  of the actuating arms  6 ,  7  of the pivot levers  1 ,  2  can be configured to be stepped (indicated by dashed lines in FIG. 1) so that in the closed position according to FIG. 1 the end faces  12 ,  13  overlap one another, when viewed in the axial direction of the bolts  4 ,  5 . This overlap becomes effective when the shearing action is carried out. This overlap causes advantageously a support action during the shearing step so that the formation of a burr is reliably prevented during the cutting action.  
         [0014]    The cutting device has two brackets  17  positioned between the actuating arms  6 ,  7  of the pivot levers  1 ,  2 . The brackets  17  are used to connect the cutting device to a drive device (not illustrated). Such a drive device is known in the art and is therefore not explained in more detail in this connection. Such drive devices are used in connection with presses or pressing tongs and have rolls that are fastened on a movable drive rod. This movable drive rod is movable in the longitudinal direction of the cutting device. The rolls move on plane slanted surfaces  18 ,  19  that are provided on facing inner sides of the actuating arms  6 ,  7  of the pivot levers  1 ,  2 . When the drive rod with the rolls is extended, the pivot levers  1 ,  2  are pivoted by the rolls such that their end faces  12 ,  13  come to rest against one another.  
         [0015]    The arms  10 ,  11  of the pivot levers  1 ,  2  are provided with a receiving space in the form of a recess  20 ,  21  that extends from the respective end faces  12 ,  13  of the arms  10 ,  11 . As illustrated in FIG. 2, the recesses  20 ,  21  are open in a direction toward the opposite lateral surfaces  22  and  23  of the arms  10 ,  11 . Into the recesses  20 ,  21  the cutting inserts  24 ,  25  are inserted that are identical but mirror-symmetrically arranged to one another. The cutting inserts  24 ,  25  have an opening  26 ,  27 , respectively, for passing fastening screws  28 ,  29  therethrough. The screws  28 ,  29  are screwed into the threaded bores  30 ,  31  provided in the arms  10 ,  11 . The screw heads are recessed within the cutting inserts  24 ,  25 .  
         [0016]    The cutting inserts  24 ,  25  have a substantially rectangular contour and rest with their longitudinal sides  32 ,  33  areally against the longitudinal sides  34 ,  35  of the corresponding recesses  20 ,  21 . Moreover, the cutting inserts  24 ,  25  rest areally with a narrow side  36  on the narrow side  37  of the recesses  20 ,  21 . In this way, the forces occurring during the cutting process to be described in the following are reliably transmitted onto the pivot levers  1 ,  2 .  
         [0017]    The cutting inserts  24 ,  25  project past the end faces  12 ,  13  of the arms  10 ,  11  of the pivot levers  1 ,  2 . On these projecting ends a circular section recess  38 ,  39  is provided that serves as a receptacle for the threaded rod  48  to be separated or cut.  
         [0018]    The two cutting inserts  24 ,  25  are staggered relative to one another in the direction of the pivot axis such that their cutting edges  41 ,  42  are positioned in a common shearing plane  43  that extends perpendicularly to the bolts  4 ,  5  and is positioned in the illustrated embodiment at half the width of the arms  10 ,  11  of the pivot levers  1 ,  2 .  
         [0019]    The receptacles or recesses  38 ,  39  extends across the entire thickness of the cutting inserts  24 ,  25 . When threaded rods  40  are to be cut by the cutting device, the recesses  38 ,  39  of the cutting inserts  24 ,  25  are provided with a thread that matches the thread of the threaded rod  40  that has to be cut. Therefore, when the threaded rod  40  is inserted into the cutting device, the thread of the threaded rod  40  and of the recesses  38 ,  39  engage one another in a positive-locking way.  
         [0020]    In order for the threaded rod  40  to be inserted into the recesses  38 ,  39  of the cutting inserts  24 ,  25 , the actuating arms  6 ,  7  of the pivot levers  1 ,  2  are pressed together. In this way, the arms  10 ,  11  move away from one another. The cutting inserts  24 ,  25  are moved correspondingly to such an extent that they have a spacing relative to one another. The threaded rod  40  can then be inserted into one of the two recesses  38 ,  39 . By means of the thread engagement, the threaded rod  40  is axially secured against movement within the recess  38 ,  39 , respectively. When the arms  6 ,  7  are released, the pivot levers  1 ,  2  are loaded by means of the pressure spring positioned in the recesses  8 ,  9  such that the arms  10 ,  11  together with the cutting inserts  24 ,  25  are pivoted in a direction toward one another. As soon as the recesses  38 ,  39  surround the threaded rod  40  to be cut, the pivot movement of the pivot levers  1 ,  2  is terminated. Since the two recesses  38 ,  39  are semi-circular in shape, the cutting inserts  24 ,  25  surround in this initial position the threaded rod  40  about its circumference. The end faces  12 ,  13  of the arms  10 ,  11  of the pivot levers  1 ,  2  are spaced apart from one another in this position.  
         [0021]    Subsequently, by means of the drive device the rod that supports the pressure rolls is extended. The pressure rolls move onto the slanted surfaces  18 ,  19  of the actuating arms  6 ,  7  and push them apart. This causes the cutting inserts  24 ,  25  to move in a direction toward one another. The shearing edges  41 ,  42  cut the threaded rod  40  in the area of the shearing plane  43  (FIG. 2). The cutting inserts  24 ,  25  overlap one another in the cutting position according to FIG. 2. The two sections  44 ,  45  of the threaded rod  40  produced by the cutting process will not drop out of of the cutting inserts  24 ,  25  after the shearing process because the rod sections  44 ,  45  are secured by the thread engagement with the cutting inserts  24 ,  25 . After the shearing or cutting process, the drive rod with the pressure rolls is retracted by the drive device to such an extent that, for the purpose of removing the threaded rod sections  44 ,  45 , the actuating arms  6 ,  7  of the pivot levers  1 ,  2  can be pressed against one another to such an extent that the threaded sections  44 ,  45  can be removed from the cutting inserts  24 ,  25 .  
         [0022]    Since the recesses  38 ,  39  of the cutting inserts  24 ,  25  are provided with the thread, it is ensured during the shearing process that the threaded rod sections  44 ,  45  cannot tilt relative to one another but are axially aligned relative to one another. The thread of the recesses  38 ,  39  and the threaded rods  40  prevent an undesirable pivot movement of the threaded rod sections  44 ,  45  during the separating process. In this way, the threaded end of the threaded rod section  44 ,  45  that has been cut off is not deformed and no burr is formed. Directly after the shearing process, it is therefore possible without a problem to screw a nut onto the threaded rod end that has been cut off.  
         [0023]    Since the cutting inserts  24 ,  25  are actuated by the two-arm pivot levers  1 ,  2 , the cutting device can be configured to be very compact. The two-arm configuration of the pivot levers  1 ,  2  enables for small pivot angles a satisfactorily large travel for the cutting inserts  24 ,  25  during the shearing process.  
         [0024]    Depending on the size of the threaded rod  40 , different cutting inserts  24 ,  25  can be attached to the pivot levers  1 ,  2 . The threaded rod  40  can be, for example, of the size M8, M10, and M12. The recesses  38 ,  39  in the separating or cutting inserts  24 ,  25  are shaped to match them. Since the cutting inserts  24 ,  25  are detachably mounted on the pivot levers  1 ,  2 , they can be exchanged without a problem within a very short period of time.  
         [0025]    The cutting device is embodied in the form of pressing (cropping) tongs used conventionally for pressing fittings for pipe connections. Such pressing tongs have pressing jaws with which the fittings are, for example, plastically deformed in the radial direction. It is possible to attach such pressing jaws detachably on the pivot levers  1 ,  2  so that the pressing jaws, as needed, can be exchanged simply for cutting inserts  24 ,  25 . The detachable connection can be achieved, aside from screws, by snap-on connections, for example. For driving the pressing jaws and the cutting inserts, the same drive device can be employed. In this way, a tradesman has available a universal device with which, as needed, he can plastically deform fittings for pipe connections or cut threaded rods.  
         [0026]    Instead of threaded rods, the cutting device can also be used, for example, for cutting threaded bolts, rods without a thread, and the like. These parts are inserted such into the recesses  38 ,  39  of the cutting inserts  24 ,  25  that they can be cut to the desired length by means of the shearing edges  41 ,  42 .  
         [0027]    While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.