Abstract:
The invention relates to a gripping head for grasping devices for manipulating a long workpiece in a horizontal arrangement. A gripping head with two clamping jaws which can be adjusted independently of one another can be used. In addition, a device for feeding long workpieces into a processing machine, and discharging them therefrom is proposed. At least one of the grasping devices may have a gripping head for gripping in a frictionally locking fashion one end of the workpiece which is conveyed here by the horizontal conveying means, and drive means for pulling the workpiece to be straightened into the processing section and for pushing the straightened workpiece out onto the at least one horizontal conveying means by means of the gripping head.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a gripping head having the features of the preamble of claim  1 ; a device for feeding long workpieces into a processing machine, and discharging them therefrom, having the features of the preamble of claim  10  or  11 , and a method for bend-straightening long workpieces having the features of the preamble of claim  12 . 
       TECHNOLOGICAL BACKGROUND 
       [0002]    Devices and/or methods for moving workpieces, in particular, linearly, i.e. horizontally or vertically in processing machines can be found in DE 101 14 263 C1, DE 36 01 075 C1 and DE 38 34 546 A1. 
         [0003]    Bend-straightening machines in which a long workpiece is supported vertically only at its ends in different workpiece positions at least between the bend-straightening steps are known from DE 101 44 135 C1. For this purpose, use is made of, in each case, a grasping device which has a gripping head and which also permits the workpiece to rotate about its longitudinal axis and which defines a processing section in the straightening press. The straightening press can be moved into the respectively desired bend-straightening positions along the workpiece which is supported only at its ends. In order to grasp workpieces of differing lengths, the grasping devices have variable spacing along the processing section. The workpiece which is to be processed can basically be inserted into its supports on the grasping devices by means of a crane device. This work-intensive charging process of the bend-straightening machine can be simplified by virtue of the fact that the grasping devices have pivoting means which permit a workpiece which is held ready next to the processing section and parallel thereto to be grasped and pivoted, in an approximately 180 degree pivoting step from the feeding-in position transverse with respect to its longitudinal direction into the processing section of the bend-straightening machine. At present, it is conventional to feed radially with the lifting means or the like. The last-mentioned bend-straightening machines from which the invention proceeds are marketed by the applicant as their ASV-L series. The bend-straightening process takes place automatically over the entire length of the workpiece and with high precision. 
       SUMMARY OF THE INVENTION 
       [0004]    In order to be able to simplify the manipulation, in particular feeding in and discharging as well as, if appropriate, also the turning of large workpieces in a production line and/or processing line which can, in particular, also comprise a bend-straightening machine for long workpieces, and, in particular, to be able to integrate the straightening system into continuous line production, a gripping head having the features of claim  1  is proposed. Accordingly, there is provision that the gripping head has two clamping jaws which can be adjusted independently of one another and can be rotated about a center of rotation of the gripping head. The center of rotation of the gripping head is located within the gripping head and ideally coincides with a center point axis of the workpiece. As a result, it becomes possible, inter alia, to feed in a long workpiece which is conveyed on a horizontal conveying means, such as a roller way, in the longitudinal direction of said workpiece, independently of the cross section thereof, as a straight prolongation of a processing section. The gripping head can for this purpose permit frictionally locking gripping of an end region of the long workpiece which is conveyed here by the horizontal conveying means. In addition it is possible to provide for the unstraightened workpiece to be pulled into the processing section by means of the gripping head and a drive means. In order to discharge the long workpiece out of the bend-straightening machine, the gripping head can push the straightened workpiece onto the same horizontal conveying means, or a horizontal conveying means located opposite, as a straight prolongation of the processing section. Correspondingly, at least one of the grasping devices can be moved virtually along the entire processing section together with the long workpiece, held tight by its gripping head, along the processing section. The gripping head is preferably configured in a continuously opened fashion on the inside. It is preferably closed on the circumferential side. This permits the workpiece to be fed through it over its entire length. The arrangement and dimensioning of the gripping head are preferably selected such that it can be moved through a press frame, in particular along the processing section. 
         [0005]    As is already the case in the known bend-straightening machines of the ASV-L series from MAE, the two grasping devices for the workpiece ends may be vertically adjustable in order to lower the workpiece, in each case, onto the anvils of the bend-straightening machines in the various bend-straightening positions of said workpiece. However, the straightening anvils for supporting the long workpiece can instead also basically be raised and remain lowered along the processing section between the bend-straightening sections during the longitudinal movement of the bend-straightening machine. As is already provided in DE 101 44 135 C1 and the ASV-L series from MAE, the workpiece is supported by being grasped by the two grasping devices in each case at the ends independently of its length and is turned into any desired rotational position about the longitudinal direction of the workpiece. 
         [0006]    The subject matter of the invention is also the device for feeding long workpieces into a processing machine, and discharging them therefrom, and a method for continuous line production and/or processing of long workpieces as claimed in claim  10  or  11 , which are each of independently inventive significance. 
         [0007]    While, according to the device for feeding in long workpieces and discharging them according to a first embodiment there is provision to permit the horizontal transportation of the long workpiece within the processing section by drive means for horizontally moving the gripping head, an alternative embodiment (according to claim  11 ) provides for roller blocks to be arranged between the two grasping devices, which roller blocks can be moved parallel to the grasping devices and consequently along the processing section. The roller blocks have horizontal supporting means, like rollers which correspond to a roller way and which can optionally be shifted under the processing section in such a way that they support the long workpiece at least while said workpiece is fed into the processing section and discharged therefrom. During the processing steps for the long workpiece, the horizontal supporting means can be shifted back transversely with respect to the processing section into a position in which they do not impede the processing machine. The propulsion movement of the workpiece can either take place by means of rotary drives at the rollers or alternatively in turn by means of the gripping head. 
         [0008]    A gripping head which also permits long workpieces with a nonround cross section to be handled, and allows automatic bend-straightening thereof, and which is also of independently inventive significance, can be found in claims  3 ,  4 ,  5  and  8 . The devices are suitable for processing workpieces of different lengths, wherein differences in the length between 3 m and 40 m, in particular between 4 m and 30 m, are possible. 
         [0009]    The abovementioned and the claimed components which are described in the exemplary embodiments and are to be used according to the invention are not subject, in terms of their size, shape, material selection and technical design, to any particular exceptional conditions, with the result that the selection criteria which are known in the field of application can be used without restriction. 
         [0010]    Further details, features and advantages of the subject matter of the invention can be found in the dependent claims and the following description of the associated drawing and table in which, for example, an exemplary embodiment of a bend-straightening machine, a feeding-in discharging device and a gripping head are presented. Individual features of the claims or of the embodiments can also be combined with other features of other claims and embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0011]    In the drawing: 
           [0012]      FIG. 1  shows a bend-straightening machine in a side view without a workpiece; 
           [0013]      FIGS. 2  A/B show the same bend-straightening machine in a feeding-in position ( FIG. 2A ) and in the workpiece-gripping position ( FIG. 2B ); 
           [0014]      FIGS. 3A-E  show the same bend-straightening machine with a workpiece in its bend-straightening position: before the second gripping head ( FIG. 3A ) closes, with both gripping heads closed ( FIG. 3B ), with the second gripping head ( FIG. 3C ) opened, and in a view from above ( FIG. 3D ) and during the discharging of the long workpiece ( FIG. 3E ); 
           [0015]      FIGS. 4A-E  show an alternative embodiment of a processing station for long workpieces as a sequence in a view from above; 
           [0016]      FIG. 5  shows an optional grasping device for a bend-straightening machine according to  FIGS. 1 to 4 ; 
           [0017]      FIG. 6  shows an alternative grasping device for the linear processing of long workpieces; 
           [0018]      FIGS. 7A-C  of the grasping device according to  FIG. 6  show the gripping head in an end side view for processing longitudinal workpieces with different cross-sectional shapes; 
           [0019]      FIG. 8  shows an alternative design (O shape) of a bend-straightening machine in an end-side schematic illustration; and 
           [0020]      FIG. 9  shows a plan view of a laterally open bend-straightening machine (C shape) in a highly simplified schematic illustration. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0021]    As is apparent from  FIG. 1 , a bend-straightening machine which is denoted in its entirety by  100  comprises a press frame  1  which can be moved horizontally along guide rails  4 ,  4 A,  4 B and has a vertically acting straightening head  1 A and vertically acting straightening anvils  1 B,  1 C with variable spacing. Two grasping devices  2 A,  2 B are, like the press frame  1 , displaceable longitudinally along the guide rails  4 ,  4 B of a machine base  5  in a motor-driven fashion. It is alternatively possible to provide that the press frame  1  is arranged in a stationary fashion which is not illustrated in the figures. 
         [0022]    The grasping devices  2 A and  2 B define, together with the straightening head  1 A and the straightening anvils  1 B and  1 C a processing section WP (represented by dot-dashed lines) which coincides with the workpiece W which is clamped in for the purpose of processing ( FIGS. 3A-C ). Correspondingly, the processing zone which is defined by the straightening head  1 A and straightening anvils  1 B,  1 C is a partial section of the processing section WP. As a result of the mobility of the press frame  1  along the processing section WP and of the guide rails  4 ,  4 A,  4 B parallel thereto, the bend-straightening zones can be correspondingly shifted along the processing section. The processing section WP also passes (according to the definition) entirely or partially through the gripping heads  8 A,  8 B, which are provided on the grasping devices  2 A and  2 B and are also described in more detail further below, for the purpose of supporting and driving in rotation the horizontally arranged workpiece W. Consequently, the processing section WP is at least as long as the longest possible workpiece W, which can be processed in the bend-straightening machine, together with the length of the gripping heads. 
         [0023]    In order to straighten deformations which occur directly at the workpiece end, it is, of course, also possible to move the straightening press beyond the gripping head and to move the straightening anvil/anvils under the workpiece end which projects out of the gripping head. 
         [0024]    In each case a horizontal conveying means  3  extends at at least one head end WPA and/or WPB of the processing section WP, as is clear in particular from  FIGS. 1 to 4 , for example as a roller way  3 A,  3 B, as a left-hand and right-hand prolongation EPA and EPB of the processing section WP. Likewise, a horizontal conveying means  3  can also extend as just one of the two prolongations EPA or EPB (not illustrated). 
         [0025]    In the base position, illustrated in FIG.  2 A/B, of the grasping devices  2 A,  2 B, the gripping zones of the gripping heads  8 A,  8 B are located with their center, in particular with their center of rotation, approximately in the center of the workpiece W. Owing to the vertical adjustability of the grasping devices, which can be implemented, for example, by vertical adjustability of the gripping heads, the height of the gripping head is set or pre-set in accordance with the thickness of the workpiece W, and the gripping head is therefore adapted to the height of the workpiece center relative to the roller way  3 A,  3 B. Basically, the height of the horizontal conveying means  3  can also be adapted. As is apparent from FIG.  2 A/B, the workpiece W moves, when pushed in the direction of the processing section WP, over the end of the roller way  3 A, with the result that said workpiece W projects out from the roller way. In this context, the right-hand end of the workpiece is pushed forward through the gripping head  8 A, of the left-hand grasping device  2 A in the drawing, as far as the gripping zone of the gripping head  8 B in the right-hand grasping device  2 B. Subsequently, the gripping or clamping means of the second gripping head  8 B are moved against the end zone of the workpiece W which surrounds the right-hand workpiece end WB, and is clamped to said end zone. The gripping head  8 B together with the workpiece W is then moved to the right along the processing section WP by means of the right-hand grasping device  2 B. For this purpose, a suitable drive is provided. During this time, the gripping means of the left-hand grasping device  2 A remain opened, with the result that the workpiece can be guided through the left-hand grasping device  2 A more or less unimpeded. 
         [0026]    From  FIG. 3A  it is apparent that the gripping head  8 B is in a frictionally locking connection with the workpiece W and is already shifted along the guide rail  4 B as far to the right as the workpiece length requires in order to be able to be subsequently also clamped in at its left-side end zone WA by the gripping head  8 A, as is illustrated in  FIG. 3B  for bend-straightening processes. The gripping heads  8 A/ 8 B can rotate about the longitudinal axis of the workpiece, with the result that the workpiece can be measured and bend-straightened in a customary fashion. For this purpose, the press frame  1  moves along the processing section WP in order to arrive at all the necessary bend-straightening positions along the workpiece. For the pushing out of the workpiece W from the processing section WP which is necessary after the processing of the workpiece W has ended, the workpiece W can either be pushed back into the original position shown in FIG.  2 A/B or pushed in the opposite direction onto the roller way  3 B located opposite, as illustrated in  FIG. 3C . For this purpose, the corresponding grasping device moves the gripping head (in the exemplary embodiment the left-hand one) along the processing section WP with the gripping head  8 A closed and the gripping head  8 B opened to the right. 
         [0027]    In order to move contours of the press frame  1  which impede the gripping head out of the way of, for example, the straightening anvils or the straightening head, it may be necessary to raise and/or lower the workpiece W, for example along the vertical direction arrows  45 . Alternatively or additionally, the anvils  1 B,  1 C and/or the straightening head  1 A can also be moved, in particular, in the vertical direction in such a way that conveying in or out of the workpiece W is possible, or movement through at least one gripping head is possible. 
         [0028]    A plan view of a bend-straightening machine, in particular according to  FIGS. 3A to 3C , can be seen in  FIG. 3D . In order to be able to move out of the way of the contours of the press frame  1  with its components such as, for example, the straightening head  1 A and/or the straightening anvils  1 B,  1 C when conveying the workpiece W in or out or when positioning or centering said workpiece W, it may be expedient if the gripping heads  8 A,  8 B or the grasping devices  2 A,  2 B can be moved in the horizontal direction in accordance with the direction arrows  40 , transversely with respect to the processing section WP. Mobility of the gripping heads  8 A,  8 B or of the grasping devices  2 A,  2 B in all the spatial directions, in particular in the vertical direction (vertical adjustability), in the axial direction WP and/or in the horizontal direction along the direction arrows  40  (such as, for example, according to  FIG. 9 ), i.e. substantially perpendicularly with respect to the guide rails  4 A,  4 B and rotationally about the center of rotation of the gripping head  8 A,  8 B, also serves to perform the centering of the workpiece W in the device  100 , which is necessary for the bend-processing. 
         [0029]    The transportation sequence according to  FIGS. 4A-4E  clarifies the horizontal conveyance of the long workpiece in an alternative embodiment:  FIG. 4A  shows a situation of feeding in a long workpiece W including the length measurement thereof. In accordance with the result of the length measurement, the position of two or more roller blocks  30 , positioned between the grasping devices  2 A/B, along the guide rail  4 B is adapted to the workpiece length, as illustrated in  FIG. 4B . The horizontal support means  33  which are associated with the roller blocks  30  can basically also be embodied as support rollers, such as are also used for the roller way  3 A/ 3 B. From  FIG. 4C  it is apparent how, when the barrier  20  is opened, the long workpiece W is shifted into the grasping position of the gripping heads, with support from the horizontal support means  33 . The horizontal support means  33  are subsequently pulled back from their position underneath the processing section WP into a position shown in  FIG. 4D . The processing of the long workpiece W can subsequently occur in various processing positions, as with a bend-straightening machine, while the long workpiece is temporarily clamped in at its end regions by the gripping heads  8 A and  8 B. From  FIG. 4E  it is apparent that after the processing of the long workpiece has taken place the latter can be shifted in its entirety together with the roller blocks  30  and the grasping devices  2 A/B (to the right in the drawing). While the workpiece is subsequently transported away via a roller way  3 B, it can be supported by means of the horizontal support means  33  which are again shifted under the processing section WP. A still unprocessed long workpiece of a different length and/or with a different cross section is already moved forward in this illustration through the roller way  3 A as far as a barrier  20  for the next processing cycle. The propulsion movement of the workpiece can take place either by means of rotary drives on the rollers and/or in turn by means of the gripping head. 
         [0030]    As is apparent from  FIG. 5 , a three-point bearing by means of rollers can serve as a gripping head, as is already used in the ASV-L series from MAE. However, novel gripping heads, as illustrated in  FIGS. 6 and 7  and described below, are preferred. 
         [0031]    FIGS.  6  and  7 A-C show a gripping head  8  in the manner of a two-jaw chuck. A base housing  11  is attached via vertically movable guide scales  12  to the grasping devices  2 A,  2 B which are known from  FIGS. 1 to 4 , and can be vertically adjusted with respect to the latter. The base housing  11  has a large-area central recess  11 A for pushing through workpieces W which are to be processed. On its side facing the processing section WP, the base housing  11  is adjoined by a live ring  13  which bears a rotary head  14 , which can rotate 360° about a center of rotation D in its circumferential direction. The live ring  13  is suitable for at least partially feeding through the workpiece W insofar as it comprises on the circumference a substantially closed, ring-like component, that has in the center at least one opening or a variable passage. The rotation between the base housing  11  and the rotary head  14  occurs by means of a circumferential toothing and a geared motor (not illustrated), wherein the rotary head  14  can rotate through 360° or else infinitely relative to the base housing  11 . The rotary head  14  accomodates two motor-driven spindles  15 A,  15 B in a lateral orientation, and in the present, and in this regard preferred, case a non-central orientation. Each of the two spindles is connected to one of two clamping jaws  18 A,  18 B which are located opposite one another and are adjustable independently of one another along guide rails  16 A,  16 B and with guide carriages  17 A,  17 B. The guide rails  16 A,  16 B can be arranged on one of the sides of the workpiece W or (as illustrated) on various sides. The clamping jaws secure the workpiece W which can be moved in the axial direction through the chock without a collision by virtue of the open design for the purpose of loading and unloading. By means of the clamping jaws  18 A,  18 B, the workpiece W can be centered with its virtual workpiece axis, which is intended to come to be located in the processing section WP, from a clamping position into a processing position. The center of rotation D (i.e. its rotational axis) of the gripping head then coincides with the virtual or actual workpiece axis. Gripping heads with features of the type denoted above are of independently inventive significance. 
         [0032]    As is apparent from  FIGS. 7A-C , it is possible to use the same pair of clamping jaws to clamp round, square, rectangular and other polygonal cross-sectional shapes of the workpiece. A large clamping range is covered, for example round and square rods in the range of dimensions from 120 to 150 mm or rectangular ones up to 120×600 mm, without manual intervention. The independent adjustability of the upper jaw and lower jaw equalizes the different jaw geometries  19 A,  19 B (prismatic at the top and straight at the bottom) and workpiece cross sections. Clamping jaws with features of the type denoted above are of independently inventive significance. 
         [0033]    Although the gripping heads in the figures are represented with, in each case, two clamping jaws which are different from one another, it is also possible instead to use three or more clamping jaws which are different from one another, without departing from the inventive concept. 
         [0034]    In the case of round rods, the prismatic jaw is rotated downward for the purpose of better centering. The free rotatability is particularly advantageous. Round rods can therefore be measured in a rotating fashion and shaping errors can therefore be filtered out better. The true running vectors on round rods can be positioned precisely upward, with the result that the straightening process proceeds in an optimum way. 
         [0035]    An end-side schematic view of a bend-straightening machine  100  with a closed machine frame  120  can be seen in  FIG. 8 . Arranged within the frame  120  is a guide rail  4 B along which the gripping heads  8 A,  8 B and/or the grasping devices  2 A,  2 B can be moved. In order to be able to move out of the way of, in particular, the contours of the anvils  1 B,  1 C and/or of the straightening head  1 A, the gripping heads  8 A,  8 B can be moved vertically along the direction arrows  40 ,  45 , i.e. in the height direction and/or horizontally, i.e. substantially perpendicularly to the line of action of the straightening head  1 A within the frame  120 . 
         [0036]    A schematic, highly simplified illustration of a view of a bend-straightening machine  100  which is preferably open on one side can be seen in  FIG. 9 , wherein the frame of the machine can have an approximately C-shaped profile. The workpiece W can be fed in along the processing section WP. This corresponds to travel along the dashed line. Alternatively, the workpiece can firstly be arranged parallel to the processing section in front of the press frame  1  (i.e. in front of the opening of the C-shaped frame), along the travel according to the continuous line in  FIG. 9 , before said workpiece is then moved along the direction arrow  40  into the processing position, with the result that its position after this horizontal movement corresponds to the processing section WP. Collisions of the gripping heads  8 A,  8 B with the anvils or the straightening head can therefore be avoided. 
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                 LIST OF REFERENCE SYMBOLS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1   
                 Press frame 
                 17B 
                 Guide carriage 
               
               
                 1A   
                 Straightening head 
                 18A 
                 Clamping jaw 
               
               
                 1B   
                 Straightening anvil 
                 18B 
                 Clamping jaw 
               
               
                 1C   
                 Straightening anvil 
                 19A 
                 Prismatic jaw geometry 
               
               
                 2A   
                 Grasping device 
                 19B 
                 Straight jaw geometry 
               
               
                 2B   
                 Grasping device 
                 20  
                 Barrier 
               
               
                 3   
                 Horizontal conveying 
                 30  
                 Roller blocks 
               
               
                   
                 means 
                 33  
                 Horizontal supporting 
               
               
                 3A   
                 Roller way 
                   
                 means 
               
               
                 3B   
                 Roller way 
                 40  
                 Horizontal direction 
               
               
                 4   
                 Guide rails 
                   
                 arrow 
               
               
                  4A/B 
                 Guide rails 
                 45  
                 Vertical direction 
               
               
                 5   
                 Machine base 
                   
                 arrow 
               
               
                 8   
                 Gripping head 
                 100 
                 Bend-straightening 
               
               
                 8A   
                 Gripping head 
                   
                 machine 
               
               
                 8B   
                 Gripping head 
                 120 
                 Machine frame 
               
               
                 11   
                 Base housing 
                   
                   
               
               
                 11A  
                 Central recess 
                   
                   
               
               
                 12   
                 Guide scales 
                 D 
                 Center of rotation 
               
               
                 13   
                 Live ring 
                 EPA 
                 Prolongation 
               
               
                 14   
                 Rotary head 
                 EPB 
                 Prolongation 
               
               
                 15A  
                 Spindle 
                 W 
                 Workpiece 
               
               
                 15B  
                 Spindle 
                 WA 
                 Workpiece end 
               
               
                 16A  
                 Guide rail 
                 WB 
                 Workpiece end 
               
               
                 16B  
                 Guide rail 
                 WP 
                 Processing section 
               
               
                 17A  
                 Guide carriage 
                 WPA 
                 Head end of processing 
               
               
                   
                   
                   
                 section 
               
               
                   
                   
                 WPB 
                 Head end of processing 
               
               
                   
                   
                   
                 section