Abstract:
An apparatus for machining an elongated workpiece with a tool a support column having a generally planar and vertical front wall and a pair of generally planar, parallel, and vertical side walls projecting rearward from respective outer edges of the front wall. A workpiece holder on the front wall can hold the workpiece forward of the front wall in a vertical orientation. A vertical guide secured to one of the side walls carries a vertical slide shiftable along the vertical guide. A front horizontal guide on the vertical slide forward of the front wall from the guide carries tool holder shiftable in the front horizontal guide on the vertical slide forward of the front wall and is adapted to hold the tool.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a machining apparatus. More particularly this invention concerns an apparatus for grinding, milling, boring, lathing, or otherwise machining an elongated workpiece. 
     BACKGROUND OF THE INVENTION 
     A standard apparatus for machining an elongated workpiece with a tool is described in German patent document 10 2008 037145. It has a support column having a generally planar and vertical front wall on which is mounted a workpiece holder for holding the workpiece forward of the front wall in a vertical orientation. A pair of vertical guides on the front is walls flank the workpiece holder and each carry a vertically shiftable vertical slide forward of the front wall. Each vertical slide in turn has a horizontal guide on which is mounted a respective tool holder horizontally shiftable in the respective horizontal guide on the vertical slide forward of the front wall and adapted to hold a respective tool. Thus horizontal movement of the holders on the respective vertical slides engages the tools horizontally with the workpiece in the workpiece holder and vertical movement of the vertical slides in the respective guide moves the tools vertically along the tool. 
     The problem with this construction is that it is quite wide. The guides and workpiece holder must move vertically in their own paths so that the apparatus has to be wide enough measured horizontally parallel to the front wall to accommodate all this equipment. This is disadvantageous in an operation where a number of such apparatuses need to be accommodated and, often, served by a single person or automatic loader/unloader. 
     OBJECTS OF THE INVENTION 
     It is therefore an object of the present invention to provide an improved machining apparatus for elongated workpieces. 
     Another object is the provision of such an improved machining apparatus for elongated workpieces that overcomes the above-given disadvantages, in particular that is of reduced width. 
     SUMMARY OF THE INVENTION 
     An apparatus for machining an elongated workpiece with a tool a support column having a generally planar and vertical front wall and a pair of generally planar, parallel, and vertical side walls projecting rearward from respective outer edges of the front wall. A workpiece holder on the front wall can hold the workpiece forward of the front wall in a vertical orientation. A vertical guide secured to one of the side walls carries a vertical slide shiftable along the vertical guide. A front horizontal guide on the vertical slide forward of the front wall from the guide carries tool holder shiftable in the front horizontal guide on the vertical slide forward of the front wall and is adapted to hold the tool. Thus horizontal movement of the holder on the vertical slide engages the tool horizontally with the workpiece in the workpiece holder and vertical movement of the vertical slide in the guide moves the tool vertically along the workpiece. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The above and other objects, features, and advantages will become more readily apparent from the following description, it being understood that any feature described with reference to one embodiment of the invention can be used where possible with any other embodiment and that reference numerals or letters not specifically mentioned with reference to one figure but identical to those of another refer to structure that is functionally if not structurally identical. In the accompanying drawing: 
         FIG. 1  is a small-scale elevational front view of a first embodiment of the apparatus according to the invention; 
         FIG. 2  is a view like  FIG. 1  of a second apparatus according to the invention; 
         FIG. 3  is a view like  FIG. 1  of a third apparatus according to the invention; 
         FIGS. 3   a - 3   c  are front views showing the machine of  FIG. 3  in different positions for end machining; 
         FIG. 3   d  is a top view of a fourth apparatus according to the invention; 
         FIG. 4  is a front view of a fifth apparatus in accordance with the invention; 
         FIG. 5  is a top view of the fifth apparatus; and 
         FIG. 6  is a front view of a sixth apparatus of this invention. 
     
    
    
     DETAILED DESCRIPTION 
     As seen in  FIG. 1  a machining apparatus according to the invention has a machine frame formed by a column  1  of square cross-section and having vertical and planar side walls  2  and  2 ′ and a similarly vertical and planar front wall  3  extending between front edges of the side walls  2  and  2 ′. The front wall  3  defines a plane E ( FIG. 3   d ), and the side walls  2  define parallel planes F perpendicular thereto. The side wall  2  carries a pair of vertical guide rails  5  on which a vertical slide  4  can shift vertically parallel to a vertical axis Z. An actuator  6  carried at the top of the wall  2  engages via an unillustrated ball screw with the vertical slide  4  to shift it up and down. The vertical slide  4  in turn is provided with a pair of vertically spaced and horizontally extending guide rails  16  on which a horizontal slide  15  can travel under the control of an unillustrated drive like the actuator  6 . This slide  15  in turn carries a tool holder  10  that is pivotal on the slide  15  about a horizontal axis  17  perpendicular to the plane E. The holder  10  holds tools  14  and  14 ′ and a grab  11 . 
     A workpiece holder  8  is provided on the front wall  3  and comprises a driven headstock  9  and a coaxial tailstock  22 . The headstock  9  can be moved along vertical guide rails  19  on the front wall  3  above the tailstock  22 . An actuator  6 ′ like the actuator  6  can vertically displace the headstock  9 . During machining the workpiece  7  is rotated about a vertical axis A. 
     A conveyor  26  transports unmachined workpieces  7  to a loading/unloading station  20  and moves machined workpieces  7  away from it. For loading, the grab  11  removes a workpiece  7  from the station  20  and fit it to the headstock  9  and tailstock  22 . For unloading the grab  11  takes the finished workpiece  7  and places it in the station  20 , with appropriate movement of the slide  15  in its guide  16  and of the holder  10  about its axis  17 . 
     The machining apparatus of  FIG. 2  serves for end machining. Here the workpiece  7  is clamped centrally in a vise  29  fixed on the front wall  3  forward of the plane E so that it is vertically fixed and nonrotatable. On the right-hand side wall  2 ′ of the machine, a second guide  5 ′, vertical slide  4 ′, slide  15 ′, and tool holder  10 ′ are provided, symmetrically to the first guide  5 , vertical slide  4 , guide  16 , etc. This assembly can also is move parallel to the vertical axis Z and horizontally parallel to the axis X. The symmetrical arrangement of the two tool assemblies allows workpieces  7  to be machined simultaneously on both ends. While the workpiece  7  is securely clamped in the vise  29  the tools  14  are rotated. 
     In  FIG. 3  the system is identical to that of  FIG. 2  except that instead of the vise  29  the front wall  3  carries an upper vertically shiftable headstock  9  like in  FIG. 1  and an also driven lower headstock  18  axially aligned with the upper headstock  9 . This way the workpiece  7  can have its sides machined along its full length as in  FIG. 1 , and by moving it axially back and forth between the chucks of the headstocks  9  and  18  it is also possible to machine both ends of the workpiece  7 , for instance drilling a hole in the end. A tailstock center  28  is advantageously provided on the workpiece holder  10 . This enables the workpiece  7  to be supported whenever machining does not allow clamping in the lower headstock  18 . 
     To machine the lower end of the workpiece  7 , it is first clamped in the headstock  9  and this lower end is machined by the tool  14  as shown in  FIG. 3   a . The headstock  9  then travels downward ( FIG. 3   b ) and transfers the workpiece  7  to the chuck of the lower headstock  18  and then returns to its original upper position, whereupon the workpiece holder  10  moves horizontally and pivots about its axis  17  until its tool  14  is concentric to the lower headstock  18 . The upper end of the workpiece  7  projecting up from the lower headstock  18  can then be machined ( FIG. 3   c ). 
       FIG. 3   d  shows how vertical slides  4  and  4 ′ movable vertically along the side-wall guides  5  and  5 ′ can carry is respective horizontal guide rails  32  and  32 ′ on which respective intermediate slides  33  and  33 ′ can shift horizontally forward and back parallel to the horizontal axis Y and perpendicular to the plane E. In turn the front horizontal guides  16  and  16  are fixed on the vertically and horizontally movable slides  33  and  33 ′ and carry the tool slides  15  and  15 ′. Here also tool holders  23  and  23 ′ are pivotal about vertical axes  17  on the slides  15  and  15 ′ and carry the various machining, drilling, and grinding tools  14 . The holder  23  also carries, in addition to the grab  11  and tools  14 , a steady rest  21  for holding the workpiece  7  on center during machining, if necessary. This arrangement allows the distance between tool engagement of the workpiece and machine frame to be significantly shortened. As a result, the flow of force is improved and the rigidity of the machine is significantly enhanced. 
     In the grinding machine of  FIGS. 4 and 5 , two vertical slides  4  and  4 ′, and horizontal slides  15  and  15 ′ are able to move vertically via shoes  27  ( FIG. 5 ) on the guides  5  and  5 ′ along the side walls  2  and  2 ′ of the column  1 , as is the case with the apparatus for end machining of  FIG. 3 . A grinding spindle head  24  with grinding wheel  25  carried on the slide  15 ′ can be shifted horizontally toward the workpiece  7  on the horizontal guide  16 . A multifunction unit  23  is associated with grinding spindle head  24  on the opposite side of workpiece  7 . This unit  23  is rotatably supported on the horizontal slide  15  about a vertical pivot axis  17 . 
     Various modules on the multifunction unit  23  include the self-centering steady rest  21  and two sensors  12  that support and effect in-process measurement of the workpiece  7 . The sensors  12  are concentric relative to the steady rest  21 , thereby enabling the workpiece diameter to be gauged during grinding and support to be simultaneously provided by the steady rest  21 . In addition, the grinding wheel  25  can be dressed by a unit  13  carried on the slide  15 . Loading and unloading is effected with the grab  11 , as in  FIG. 1 . 
     The arrangement of vertical slides  4  and  4 ′ on both walls  2  and  2 ′, and of the workpiece holder on the front wall  3  of the column  1  produces an especially rigid construction for the machine. The grinding machine is nevertheless extremely compact and takes up only a small footprint. In addition, the machine can be flexibly employed because the multifunction unit  23  together with different tools  14  and the steady rest  21  enable complex machining procedures to be performed. A total of only four controlled linear axes is required since the grab  11 , the sensor  12 , and the dressing unit  13  are all mounted on the multifunction unit  23  that is movable in two axes. For loading and unloading, the grab  11  removes workpieces  7  from the station  20  and feeds them to the headstock  9 . As this occurs, the horizontal slide travels along the guide rails  16 , while the tool holder  10  pivots about the pivot axis  17 . 
       FIG. 6  shows a four-axis grinding machine for synchronous grinding. Here two grinders  24  and  24 ′ are disposed in mirror-inverted fashion, and can move in the X axis and Z axis on the respective vertical slides  4  and  4 ′ and horizontal slides  15  and,  15 ′. This arrangement enables, for example, a main bearing  30  of a crankshaft to be ground. Similarly, the crank pins  31  of a center-clamped crankshaft can be machined using the pendulum-stroke method.