Abstract:
The invention relates to a method for separating workpieces, in particular forged tins, by means of at least one driving device and one clamping device, in which the work piece is maintained, whereby the work piece is cut through by means of at least one sawing device. According to the method, the workpiece may be rotatably driven in relation to the sawing device, for the separation thereof.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a method for separating workpieces, in particular forged bushes, with at least one driving device and one clamping device, in which the workpiece is held, the workpiece being cut through with at least one sawing device and, for cutting-through, the workpiece being driven rotatably with respect to the sawing device, and also to an apparatus for carrying out the method.  
         [0002]     Such methods and apparatuses are already known on the market in various forms and designs. Circular saws and band saws with which workpieces can be cut through are known. With these, a workpiece is clamped on the machine frame in such a way that it remains immovable during working. In the case of a circular saw, the workpiece is cut through with a rotating saw blade. In the case of a band saw, the workpiece is cut through by means of a moving endless sawing band. In both cases, the tool moves, but the workpiece does not.  
         [0003]     It is disadvantageous that a change in the cut shape may occur if the workpiece consists of a hard material and it cannot easily be cut through. Parallelism cannot be achieved on the cut-through workpiece without further finishing work.  
         [0004]     To cut completely through a workpiece by means of a rotary driven saw blade, its diameter must either be equal to the diameter of the workpiece to be cut through or else larger by a multiple than that of the workpiece in order that a good cutting performance can be achieved.  
         [0005]     Since the saws usually operate at high speed, it is possible in the case of such methods and apparatuses for heat to develop at the workpiece, since both the saw blade and the endless sawing band move only in a small region of the circumference of the workpiece during the cutting-through of the workpiece.  
         [0006]     The surface roughness is also not optimal in the case of the aforementioned methods and apparatuses, since the saws do not run uniformly through the workpiece. To achieve good quality, it is therefore essential to carry out finishing work on the workpiece, which is undesired.  
         [0007]     The larger the workpiece, the longer it takes to cut through the workpiece, whereby on the other hand the costs with regard to wear of the tools, energy, etc. increase. This is time-consuming, costly and energy-intensive, which is undesired.  
         [0008]     The object of the present invention is to eliminate the aforementioned disadvantages and provide a method and an apparatus which make it possible to cut through workpieces without finishing work being necessary on the workpiece with regard to surface roughness and parallelism. It is likewise desired for the saw blade to pass through the workpiece with low wear. Furthermore, the development of heat at the workpiece and at the tool is to be minimized. Furthermore, the working time is to be reduced considerably.  
         [0009]     DE 29 49 921 discloses an apparatus for mechanically working the circumference of workpieces in the form of rings or bushes, in which the workpiece to be worked on is moved with respect to a tool or a cutting tool.  
         [0010]     U.S. Pat. No. 4,412,401 discloses an apparatus for cutting through tubes of relatively large diameter, a tube resting on corresponding roller elements, and it being possible for it to be cut to length by means of a circular cross-cut saw by turning of the tube.  
         [0011]     A similar machine for cutting through tubes is disclosed by U.S. Pat. No. 4,901,611, a workpiece that is to be worked resting on two roll elements and it being possible for to be cut through by means of a transversely movable saw.  
         [0012]     DE 1 502 693 describes an apparatus for clamping and at the same time turning workpieces on two roll elements, the workpiece being embraced by means of a belt element for driving or for rotary driving. A corresponding rotatably pivotable circular cross-cut saw cuts through the workpiece.  
       SUMMARY OF THE INVENTION  
       [0013]     The features of the characterizing clauses of claims  1  and  4  lead to the achievement of this object.  
         [0014]     The saw blade moves counter to the workpiece, the development of heat being reduced.  
         [0015]     Finishing work is no longer necessary on the workpiece, since both the saw blade and the workpiece move on a prescribed path. This has the effect that there is no change in the cut shape, i.e. the parallelism. The surface roughness is now only minimal and the saw blade runs uniformly through the workpiece.  
         [0016]     It is also of advantage to reduce the diameter of the saw blade considerably in comparison with the diameter of the workpiece to be cut through, whereby costs and energy are saved. Moreover, the working time for sawing through the workpiece can be reduced significantly.  
         [0017]     Since the sawing-through takes place in the case of the present invention without coolants or additives, it is of advantage that chips that are produced can be collected and melted down again without having to be passed on to a separate refining operation.  
         [0018]     When this method is used, there is also far less wearing of saw blades than in the case of previously known methods, since the saw blade engages only in the outer, rotating circumferential region of the workpiece.  
         [0019]     The apparatus has a drive device which is connected to the clamping device and with which the workpiece to be worked on is held. In addition, the workpiece lies on the rollers of the receiving device. The workpiece is supported on the rollers and held in a resilient and/or damping manner during working.  
         [0020]     The rollers of the receiving device rest on elements which permit sprung and/or damped mounting. The rollers themselves may be freely movable or actively driven and have a drive of their own, for example in the form of a servo motor or electric motor.  
         [0021]     A linear guide may be used as the guiding device for the movement of the receiving device in the Z direction, but any other guiding device known according to the prior art is possible.  
         [0022]     The same applies to the infeeding device in the form of the spindle, which ensures the advancement of the saw blade in the direction of the workpiece. Instead of a spindle, a hydraulic device, a rail or a linear drive may similarly be provided. Here, too, no limits are to be imposed on the invention.  
         [0023]     Furthermore, in the case of the apparatus it is possible to provide a catching device, which catches the cut-through workpiece and consequently prevents the saw blade from becoming jammed and damaged.  
         [0024]     It is also intended to be within the scope of the present invention for very long forged, preferably multiply forged, bushes to be received on individual rollers or roller elements, in order to saw individual rings off these bushes. In this case it is also intended to be within the scope of the present invention for it to be possible for a plurality of saw blades to be arranged one behind the other or one next to the other, in order to saw a number of rings off the bush simultaneously in the way described above.  
         [0025]     Furthermore, it has proven to be advantageous in the case of the present invention to use such apparatuses not only for sawing rings off rolls or forged bushes; turned or drawn round stock, tubes, shafts, etc. can also be worked in the way described above and corresponding rings or disks sawn off. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]     Further advantages, features and details of the invention emerge from the description which follows of preferred exemplary embodiments dots on the basis of the drawing, in which:  
         [0027]      FIG. 1  shows a front view of the apparatus for separating workpieces according to the present invention;  
         [0028]      FIG. 2  shows a side view of the apparatus according to  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0029]     According to  FIG. 1 , an apparatus R 1  has a machine frame  1 , on which a sawing device  2  is movably arranged, and also a clamping device  3  with a driving device  4  and a receiving device  5  for a workpiece  6 . Here, the workpiece  6  is a singly or multiply forged copper bush.  
         [0030]     The machine frame  1  comprises two side supports  7 ,  8 , which butt with their respective ends against a ceiling  9  and a base  10 . Arranged between the two supports  7 ,  8  are at least two cross members  11 ,  12 .  
         [0031]     Arranged on these cross members  11  and  12  is a compound slide  13  of the sawing device  2 , which has a base plate  14  and a plate  15  pivotably mounted on it. The compound slide  13  can be made to move with respect to the cross member  11 ,  12  in a Y direction and is also mounted in such a way that it can be fixed in a desired position.  
         [0032]     The plate  15  has on its upper side a guide  16 , into which one end of an infeeding device  17 , in particular a spindle, enters. The other end of the spindle  17  is connected to a driving element  18 . The spindle  17  is guided in a further guide  19 , which is assigned to the upper side of the base plate  14 .  
         [0033]     Arranged spaced apart from one another on the plate  15  are two transverse struts  20 ,  21 , with a shaft  22  which is mounted with its one end in the transverse strut  20  and passes through the transverse strut  21  being provided. With its other end, it is in connection with a driving element  23 . This driving element  23  rests on a plate  24  protruding from the transverse strut  21 .  
         [0034]     On the shaft  22  there is also at least one saw blade  25  arranged displaceably by means of a connecting piece  26 .  
         [0035]     The clamping device  3  has a frame  27 . Fastened on one side of this frame are clamping jaws  28 , which firmly clamp the workpiece  6  between them. On the other side, the frame  27  is connected to a drive shaft  29 , which connects the frame  27  and consequently the clamping device  3  to the driving device  4 .  
         [0036]     The receiving device  5 , on which the workpiece  6  rests during working, is guided by means of slide elements  30 ,  31  on guide rails  32 ,  33 . The slide elements  30 ,  31  and the guide rails  32 ,  33  together form the guiding device  34 . The slide elements  30 ,  31  can be fixed re-releasably in a desired position with respect to the guide rails  32 ,  33 .  
         [0037]     Arranged on the slide elements  30 ,  31  are two transverse struts  35 ,  36 , in which an element  37  is telescopically mounted respectively at the end. Arranged around the element  37  are springs  38 , which bring about additional resilience.  
         [0038]     Arranged on each element  37  is a plate  39 , on which in turn an element  40  for receiving and mounting rollers  41 ,  42  is fastened.  
         [0039]     The elements  37  with the springs  38  allow a movement of the rollers  41 ,  42  in the X direction represented. Furthermore, the rollers  41 ,  42  can be made to move along the guide rails  32 ,  33  in a Z direction by means of the slide elements  30 ,  31 .  
         [0040]     Likewise assigned to the receiving device  5  is a catching device  55 , which serves for receiving a sawn-through workpiece. The catching device  55  is fastened in the interior of the workpiece  6  by means of fixing elements  56 .  
         [0041]     In  FIG. 2 , a supporting plate  43  is provided for the driving element  18  of the spindle  17 , which bears against the base plate  14  of the compound slide  13  of the sawing device  2 . Also arranged on the compound slide  13  is a joint  44 , which pivotably connects the plate  15  to the base plate  14 .  
         [0042]     The clamping device  3  has transverse bracing means  45 ,  46 , which are arranged on the frame  27 .  
         [0043]     In  FIG. 3 , a further exemplary embodiment of the present invention is represented. There, the workpiece  6  is clamped in a vertical or else horizontal position by the clamping jaws  28  of the clamping device  3  and also if appropriate by further clamping jaws  47 .  
         [0044]     These clamping jaws  47  are fastened on a frame  48  of a further clamping device  49 , which is arranged on the ceiling  9  by means of a telescopic linkage  50 . The displacing of this linkage  50  takes place according to the size of the workpiece to be held, for example by means of a piston-cylinder unit.  
         [0045]     The driving device  4  to which the clamping device  3  is connected has on its circumference a guiding device  51 , which serves for the rotary reception of a holding arm  54 . 1 . The latter can be driven about an axis A 3  in the direction of the double-headed arrow represented.  
         [0046]     The holding arm  54 . 1  is adjoined by a holding arm  54 . 2 , which moves with respect to the latter in a Z direction and on which the sawing device  2  is mounted. Moving of the holding arms  54 . 1 ,  54 . 2  with respect to one another takes place for example by means of a piston-cylinder unit. The sawing device  2  corresponds to the type described above.  
         [0047]     The mode of operation of the present invention is as follows:  
         [0048]     The workpiece  6  is placed on the rollers  41  and  42  of the receiving device  5  and clamped in the clamping device  3  by the clamping jaws  28 . Depending on the size of the workpiece  6 , the rollers  41 ,  42  of the receiving device  5  may be moved apart or toward one another by means of the guiding device  34  in the Z direction represented, so that the rollers  41 ,  42  bear off-center and laterally against the workpiece  6 . They support the workpiece  6  during working, since the surface of the latter is not uniform.  
         [0049]     The clamping device  3  together with the clamped workpiece  6  is subsequently set in rotation about an axis A 1  by the driving device  4  by means of the drive shaft  29 .  
         [0050]     If the workpiece  6  is driven, the rollers  41  and  42  also rotate under the workpiece  6  about an axis A 2  in each case. The connection of these rollers  41 ,  42  to the element  37  and the springs  38  has the effect of absorbing shocks which may occur due to irregularities of the surface on the workpiece  6 , in particular in the case of forged bushes.  
         [0051]     In order to saw through the workpiece  6  at a desired point, the sawing device  2  on the machine frame  1  is manually and/or automatically made to move into the desired position.  
         [0052]     Once the sawing device  2  is in the desired position, the plate  15  is moved by the spindle  17 , which is driven by the driving element  18 , about the joint  44  so far in the direction of the arrow Z′ that the saw blade  25  engages in the workpiece  6 . The saw blade  25  is driven by means of the driving element  23  during the infeeding of the plate  15  and can saw through the workpiece  6 , the workpiece  6  being driven during the sawing operation. The advancement of the sawing device  2  or of the saw blade  25  takes place continuously and controllably, while the workpiece  6  is rotatably driven.  
         [0053]     It should be emphasized particularly here that the driving movements of the saw blade  25  and of the workpiece  6  are counter to one another, so that faster sawing-through of the workpiece  6  can be carried out.  
         [0054]     It is also intended to be within the scope of the present invention for example for the workpiece  6  to be clamped between three roller elements  40 ,  41  if appropriate of a clamping roller resting on top, it then being possible if appropriate to dispense with the driving device  4 . This is then driven for example by one of the three rollers  41 ,  42 . This is likewise intended to be within the scope of the present invention.  
         [0055]     In the case of the further exemplary embodiment according to  FIG. 3 , the workpiece  6  is not set in rotation, but is firmly clamped between the clamping jaws  28  of the clamping device  2  and the clamping jaws  47  of the clamping device  49 . The workpiece  6  is fixed.  
         [0056]     The holding arm  54 . 1 , which is adjoined by the holding arm  54 . 2 , is driven in a controllable manner rotatably around the driving device  4  about the axis A 3 .  
         [0057]     Mounted on the holding arm  54 . 2  is the sawing device  2 , which can also be made to move with respect to the holding arms  54 . 1 ,  54 . 2  in an X direction for the setting of a desired position.  
         [0058]     For sawing through the workpiece  6 , the holding arm  54 . 1 ,  54 . 2  with the sawing device  2  fastened to it rotates about the axis A 3  around the workpiece  6  and in this way cuts through the workpiece  6  at any desired height with a saw blade  25  preferably driven counter to it, with infeeding of the sawing device  2  toward the workpiece  6 .