Patent Publication Number: US-7210328-B2

Title: Metal sheet folding device with depositing/positioning device

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a metal sheet folding device, particularly a folding press, which is comprised of a table beam that is stationarily arranged on a machine frame; a press beam on the machine frame that is adjustable in guide arrangements in relation to the press table beam and provided with a driving device; and a depositing and positioning device for depositing at least one metal sheet plate or workpiece for intermediately positioning the latter and fully clasping it by means of the gripping equipment of a handling device. 
   2. Prior Art 
   A stationary stacking table for readying plate-like workpieces that are to be received by a handling device that is displaceable along the folding press in a linear guiding arrangement for serving a folding press, is known from patent document JP 2002 153929. In addition, provision is made for a stationary receiving device arranged within the gripping range of the handling device. The receiving device serves for intermediately depositing the workpieces, so that the gripping device can be repositioned between two folding steps carried out on a workpiece if this is required for carrying out the subsequent folding step. The device for intermediately depositing the workpiece is fitted with holding devices, so that after the workpiece has been deposited, it can be retained in a reference position for the gripping operation without any change in the position. The necessary clasping operation requires a method and adjustment of the handling device outside of the immediate vicinity of the folding press, resulting in longer periods of idling of the folding press. 
   SUMMARY OF THE INVENTION 
   The problem of the invention is to provide a metal sheet folding system with a depositing and positioning device that reduces the time span that has to be expended for fully clasping the workpiece with a gripping device between individual work steps. 
   The problem is resolved in that the depositing device is adjustably supported on the machine frame, preferably on the beam of the press table, and adjustable in a linear guide arrangement in the direction of the longitudinal expanse of the table beam over at least part of the length of the latter. A surprising advantage is gained in this manner in that while a folding step is still in progress, the depositing device is already adjusted independently of the handling device for the next gripping operation and set to a position that permits the workpiece to be deposited and clasped without displacing the handling device, thus saving idle time. 
   Beneficial in this connection is an embodiment of the metal sheet folding equipment where the depositing/positioning device is formed by support consoles that are adjustable independently of each other in relation to one another in the guide arrangement, such support consoles forming with cantilevered arms an alignment plane extending approximately perpendicular to the adjustment and work plane of the press beam. This permits changing the spacing between the support consoles directly via the adjusting servo-drives, so that such spacing can be adapted to the metal sheet plates or workpieces that are to be received and positioned. 
   Beneficial, however, is also an embodiment in which the support console is formed by two profiled legs arranged at right angles relative to one another. One of said profiled legs is extending perpendicularly to the set-up surface of the metal sheet folding machine, and the other profiled leg is extending perpendicularly to the adjustment and work plane, which permits obtaining a simple engineering solution for the construction of the support console. 
   However, an embodiment where the support device is formed by a carriage that is fitted with cantilevered arms and adjustably arranged in the guide arrangement, is advantageous as well in that the controlling and regulating expenditure is reduced in this way. 
   Possible are also advantageous embodiments of the metal sheet folding device where the cantilevered arms are extending perpendicularly to the adjustment and work place, and/or where at least one cantilevered arm is supported on the carriage in a linear guide and adjustable therein in relation to the other cantilevered arm, and/or where the cantilevered arm is adjustable by means of an adjusting servo-cylinder or spindle drive, because the support device can be quickly adapted to changed requirements in this way. 
   A low weight is gained and the force due to mass and the required driving output are consequently reduced owing to the fact that the carriage is formed by a sheet metal component. 
   Owing to the fact that the support consoles are adjustable in relation to each other or synchronously with each other via adjusting servo-drives, for example electric motors that are controllable independently of each other, and/or the servo-drive is arranged on the carriage, and/or the servo-drive is in driving connection with a toothed rack arranged on the machine frame or the press table beam and extending parallel to guide rails, e.g. flat track guides, round bar guides etc., and/or the servo-drive is formed by a spindle drive, very rapid adjustment movements and thus short adjustment periods are achieved. 
   However, an embodiment of the metal sheet folding device in which the adjusting servo-drive is formed by a servo-cylinder to which a pressure medium is admitted, is advantageous as well in that it permits achieving a simplified solution that is consequently favorable in terms of cost. 
   A quite universally adjustable depositing/positioning device is obtained with other advantageous embodiments as well, so that extensive refitting work can be dispensed with in many cases when changing to different workpieces. 
   Finally, an embodiment of the metal sheet folding device is advantageous where each support console or the carriage are connected to a controller of the sheet metal folding device via a strand of supply cable lines, e.g. a strand of trailing cables, for supplying, e.g. control signals and/or energy and/or a supply system, for example for a pressure medium, because the depositing/positioning device is integrated in this way in the overall control system of the metal sheet folding equipment. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For the sake of better understanding, the invention is explained in greater detail with the help of the exemplified embodiments shown in the figures, in which: 
       FIG. 1  is a simplified schematic representation of the metal sheet folding device as defined by the invention; 
       FIG. 2  is a detailed view of the metal sheet folding device as defined by the invention, with sections according to lines II—II in  FIG. 3 ; 
       FIG. 3  is a top view of a detail of the metal sheet folding device; 
       FIG. 4  is a simplified schematic representation of another embodiment of the metal sheet folding device as defined by the invention; and 
       FIG. 5  is a detailed view of the other embodiment of the metal sheet folding device. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   It is noted herewith by way of introduction that identical components are provided in the different embodiments with identical reference numbers and identical component designations, whereby the disclosures contained throughout the specification can be applied in the same sense to identical components with identical reference numbers and identical component designations. Furthermore, the positional data selected in the specification such as, for example “top”, “bottom”, “lateral” etc., relate to the directly described and shown figure, and are applicable in the same sense where a position has changed. Moreover, individual features or combinations of features of the different exemplified embodiments shown and described herein may represent independent inventive solutions, or solutions as defined by the invention. 
     FIGS. 1 to 3  show a metal sheet folding device  1 , particularly a folding press for reshaping the metal sheets  2  into the workpieces  3  between the folding dies  4  and  5 , which are adjustable relative to each other. The machine frame  8 , which is substantially formed by the C-shaped lateral stands  6  that are aligned parallel to each other and spaced apart, and the corresponding connecting sections  7 , has a table beam  9  secured on the lateral stands  6  that is anchored in a fixed manner on the faces of legs of the lateral stands  6 , for example screwed or welded, etc., to said faces. The lateral stands  6  with the table beam  9  are directly supported on the set-up surface  10 , or supported thereon via set-up elements. A press beam  13  that is adjustable via the drives  12 , e.g. hydraulic cylinders or spindle drives, is supported opposite the table beam  9  in the guide arrangements  11  on the additional legs of the C-shaped lateral stands  6 . The die chucks  16  for chucking the folding dies  4 ,  5  are arranged on faces of the press beam  14  and the table beam  9  opposing each other. The folding dies  4 ,  5  are adapted to conform to the folding operation to be carried out, whereby the standard equipment for such folding operations comprises a lower folding die with a V-shaped recess, and an upper die with a profiling approximately matching the V-shaped profiling of the lower die. Such dies are exchangeably secured in the die chucks  16  of the table beam  9  and the adjustable press beam  14 . The folding dies are usually assembled from several individual dies, so that the length of the die can be selected as required for the intended folding length. 
   The metal sheet plate  2  is reshaped to a preset folding angle by linearly folding it between the folding dies. The engagement between said dies is adjustable, whereby the depth of immersion required for obtaining the preset folding angle is set by controlling the drives  12  via the controller  17  of the folding press  1 . 
   It is noted that the folding device  1  comprises a number of measuring, controlling and regulating systems, as well as sensors and safety devices of the type known in the prior art, which need not be addressed here in greater detail. 
   Such metal sheet folding devices  1  are fed in many cases with a handling system  18 , particularly a multi-axis robot especially when workpieces  3  are produced in series. The metal sheet plate  2  or workpiece  3  is usually retained by the handling device  18  during one or several successive folding operations, and the required sequence of movements is jointly performed by the handling device  18  as well. 
   Such a handling device  18  is preferably displaceably arranged parallel to the table beam  9  and displaced on the set-up surface  10 , for example in guides over at least a length  19  of the table beam  9 . In this way, several work positions and sets of dies can be arranged distributed over the length  19  of the table beam  9  or press beam  13 , so that the metal sheet folding device  1  can be fitted for a number of different reshaping operations, which permits achieving high economy in the production of the workpieces  3 . 
   For carrying out a folding operation on the metal sheet plate  2  or workpiece  3  that has already been partly reshaped previously, the latter is picked up by means of a gripping device  20 , which is hinged on an arm  21  of the handling device  18 , whereby preferably two rotating devices  22  are interconnected, forming the two axles of rotation  23 ,  24  extending vertically relative to each other. The metal sheet plate or workpiece is then positioned between the folding dies  4 ,  5 , and the folding step is carried out by adjusting the press beam  13 . 
   In a feasible embodiment, provision is made on the gripping device  20  for an optical detection system for acquiring the position of the workpiece for identifying it, and in order to exactly position the gripping device  20  on the metal sheet plate  2  or workpiece  3  when the latter is picked up for the first time from a stack, or also after it has been intermediately deposited, for example if it has to be fully clasped. 
   As shown in the exemplified embodiment, the gripping device  20  is fitted with the suction cups  25 ; however, it is possible to employ finger-like grippers, magnetic gripper etc. as well. 
   As mentioned above, the metal sheet plate  2  or workpiece  3  is retained by the gripping device  20  while it is being reshaped by folding. The arm  21  of the handling device  18  is jointly performing the required adjustment movement. The sequence of movements is realized by controlling drives of the handling device  18  via the controller  17  of the folding device  1  as well, using a network of the control system. 
   The gripping position of the gripping device  20  on the metal sheet plate  2  or workpiece  3  often has to be changed between two successive folding operations carried out on the metal sheet plate  2  or workpiece  3  that has already been partly shaped previously. 
   A depositing/positioning device  26  serves for carrying out a seizing step in which the metal sheet plate  2  or workpiece  3  is fully clasped. For this purpose, the latter is deposited on said device  26  in a defined position, retained in the position in which it is deposited, and picked up again after the gripping position has been changed by adjusting the gripping device  20 . As shown by way of example by the broken lines, it may be necessary to seize the metal sheet plate  2  or workpiece  3  on the surfaces  27 ,  28  opposing one another. However, it may be naturally necessary also to newly position or reposition the gripping device in its gripping position on the same surface  27 ,  28  for subsequent folding steps in order to permit the metal sheet plate  2  or workpiece  3  to be inserted between the folding dies  4 ,  5  for carrying out another folding operation. 
   Now, the figures show that in a feasible embodiment of the depositing/positioning device  26 , provision is made for the two support consoles  29 ,  30  arranged on the table beam  9  of the folding device  1 . Said support consoles are adjustably supported in the linear guide arrangements  31 , which are extending, for example in the direction of the length  19  of the table beam  9 , and arranged on a surface  33 . The support consoles  29 ,  30  are displaceable independently of one another by means of the servo-drives  36 , e.g. electric motors and a toothed-rack drive  37 . The servo-drives  36  are actuated and controlled in accordance with a program sequence by the controller  17  of the folding device  1 . 
   As shown in the exemplified embodiment, the support consoles  29 ,  30  are each formed by the two profiled legs  31 ,  32  arranged at right angles in relation to one another, whereof the profiled leg  39  is aligned parallel to the surface  33 , and displaceably supported in the guide arrangement  31  formed by the guide rails  34 ,  35 . The other profiled leg  38  is forming a cantilevered arm  40 , whereby the top sides  41  of the cantilevered arms  40 , said top sides being aligned with each other, are forming the alignment plane  43  extending perpendicularly to the adjustment and work plane  42 . On the top sides  41  of the cantilevered arms  40  of the support consoles  29 ,  30 , said arms extending parallel to each other with an adjustable spacing  44  from one another, the cantilevered arms  45  pointing at each other are detachably secured as required, and can be positioned in the direction of a length of the cantilevered arms  40 . In end areas pointing at each other, the cantilevered arms  45  are provided with at least one support means  46 , which is designed to serve also as a holding means  47 , and is formed, for example by a suction cup to which vacuum is admitted, or by an electromagnet etc. A support plane  48  formed by the holding means  46  is preferably extending parallel to the alignment plane  43  and perpendicularly to the adjustment and work plane  42 . 
   As shown in  FIG. 2 , such a design assures that the surface  27  and  28  of the gripping device  20  opposing one another can now freely access the metal sheet plate  2  or workpiece  3  received by the holding device  26 . 
   Owing to the fact that the support consoles  29  and  30  can be adjusted independently of one another, the spacing  44  can be adapted to the given outside dimensions of the metal sheet plate  2  or workpiece  3  to be received. 
   However, the fact that the support consoles  29  and  30  can be synchronously adjusted is important as well in that this permits driving the entire depositing/positioning/holding device  26  along the table beam  9  into a position in which a metal sheet plate  2  or workpiece  3  can be deposited and fully gripped by said device with a minimum of idle time. This can take place without influencing a folding operation that is in progress at the time an adjustment is made, and travel time for the handling device is significantly reduced. 
   As shown in  FIG. 2 , the support consoles  29  and  30 , which are independent of each other, are each supplied by means of their own supply cable harnesses  48 , e.g. so-called trailing cable caterpillars for transmitting control signals, energy, pressure medium etc. 
   Now,  FIGS. 4 and 5  show another embodiment of the metal sheet folding device  1  with the sheet-depositing/positioning device  26 . 
   According to said embodiment, a carriage  50  equipped with the servo-drive  36  is arranged in the guide arrangements  31  on the table beam  9  and displaceable in the longitudinal direction of the table beam  9 . In the exemplified embodiment shown, the guide arrangement is comprised of the round bar guides  51  and  52 , which are secured on the table beam  9 . The carriage  50  is supported on said bar guides, for example via rollers or rotating ball bushings. The servo-drive  36  is, for example an electric motor  53 , which, via a pinion, is in driving connection with a rack secured on the table beam  9 . 
   The carriage  50  is preferably made of a lightweight construction, e.g. in the form of a U-shaped sheet metal component with a base leg  55  and the lateral legs  56  and  57  extending approximately at right angles to the base leg. The electric motor  53  of the servo-drive  36  is secured, for example on one of the lateral legs  56  and  57 , or between said legs on a connecting strut  58 . The guide elements  59  cooperating with the round bar guides  51  and  52  are arranged in the base leg  55  and/or the lateral legs  56  and  57 . One of the two cantilevered arms  40  is secured on the top side  60  of the base leg  55 , said top side extending parallel to the face  14  of the table beam, and cantilevered in the vertical direction in relation to the surface  33 . The other cantilevered arm  40  extending parallel thereto is adjustable in the linear guide  61  of the base leg  55  in relation to the stationary cantilevered arm  40 , as indicated by the double arrow  62 , so that the spacing  44  between the cantilevered arms  40  can be adjusted as required in accordance with the given outside dimensions of the metal sheet plate  2  or workpiece  3  to be deposited on the support device  26 , for carrying out the gripping operation. 
   The cantilevered arm  40  is adjusted, for example via an electric motor-driven spindle drive  63  provided on the carriage  50 , or via a pressure-operated cylinder. 
   The cantilevered arms  40  are fitted with the holding means  47 , e.g. suction cups, which are adjustable in the direction of the length of the cantilevered arms  40 . As already described above, however, it is possible also to make provision on the cantilevered arms  40  for the support arms  45 , which in turn can be provided with the holding means  47 . According to another embodiment, it is possible to make provision that the support arms  45  can be adjusted lengthwise, or to employ servo-cylinders, servo-spindles etc. as supports for the holding means  47 . 
   Furthermore, it is noted that positioning/stop elements can be provided on the cantilevered arms  40  and/or support arms  45 , on which the metal sheet plate  2  or workpiece  3  can be positioned. 
   However, according to a preferred embodiment, provision is made that the gripping device  20  is operated with an optical position detection system, in which case no mechanical positioning aids are required. 
   As already described above as well, provision can be made for the supply cable strand  48 , e.g. the trailing chain cable harness  49  for controlling and supplying the drives and sensors with energy; control signals; pressure medium etc. 
   The exemplified embodiments show possible design variations of the metal sheet folding equipment, whereby it is noted here that the invention, however, is not limited to the design variations specifically shown herein, but that also various combinations of the individual design variations among one another are feasible, and that due to the instruction for technical execution of the present invention, such variation possibility falls within the scope of the skills of the expert engaged in the present technical field. 
   Therefore, any and all conceivable design variations feasible by combining individual details of the design variation shown and specified herein, are jointly covered by the scope of protection as well. 
   For the sake of good order, it is finally pointed out that in the interest of superior understanding of the structure of the metal sheet folding equipment, the latter and its components are to some extent shown untrue to scale and/or enlarged and/or reduced. 
   Most of all, the individual embodiments shown in  FIGS. 1 ,  2 ,  3 ;  4 ,  5  may form the object of independent inventive solutions. Their problems and solutions as defined by the invention are disclosed by the detailed descriptions of said figures.