Patent Publication Number: US-9849499-B2

Title: Device and method for transferring workpieces into and out of a tool

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a method and device for transferring work pieces into and out of a tool, in particular a multi-staged cutting and processing tool, wherein a blank is cut out of a clamped flat strip in an upper part. 
     A method and device are known from EP2 036 629 B1 for fine blanking and forming of a work piece made from a flat strip, wherein a plurality of processing stages lie in a circular path. The work pieces are transferred from one processing stage to the next by way of a rotatable cutting plate. This results in the cutting plate having both a cutting function and a transport function, which leads on one hand to a complicated design of the fine blanking tool and on the other hand encourages wear in the cutting plate due to the continuous sequence of aligning and locating in order to cut the work pieces and the rotational movement to transport the work pieces. Therefore, continuous monitoring of the active elements is required to maintain the precision and accuracy of the fine-blanked parts. 
     There is also a device known from EP 2 444 172 A1 for removing precision-punched or fine-blanked parts from a tool. The device makes use of a linearly movable cross slide to transport the work piece, the cross slide being movable into the work space between the working parts when the tool is opened, and out of the tool when it is closed. For multi-staged tools, this means that each work operation can only be carried out after the cross slide is moved out of the tool. The time it takes to open the tool must be accounted for, increasing the finishing time per part and decreasing productivity. Also, the linear slides require sufficient space and therefore make compact tool design difficult. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a device and a method for transferring work pieces in and out of multi-staged cutting and processing tools that eliminates the need to move the slide into and out of the tool while at the same time increasing the number of strokes and economic efficiency, degree of precision in the parts, improved compactness in the tool, and a simplified design. 
     Of significance is that the slide is designed as a rotary slide including a plurality of transfer openings and a discharge opening. Also, the cutting stage and the individual processing stages are designed with a discharge stage as separate, mutually-supporting components arranged about a rotating axis of the rotary slide, the axis being supported at the lower block. The transfer openings and the discharge opening lie in a circular path that coincides with the circular paths of the active elements of the cutting stage, the processing stages and the discharge stage. The transfer openings have a distance from one another that is identical to the arc distance between the active elements in the circular paths. 
     This is achieved in that the rotary slide comprises a slide plate in which the transfer openings and the discharge opening are matched to the size and shape of the cutting and processing stages in order to accommodate the blanks. The slide plate is connected to a linear drive that is arranged approximately tangential to the lower pressure plate and the lower frames coaxial to the circular path. The drive executes a horizontal pivoting motion of the plate about a rotating axis fixed at the lower block of the lower part. The slide plate connection is such that the transfer openings located in the circular path and the discharge opening of the slide plate seize the blanks after the plate pivots in the direction of the cutting stage by an amount equal to the arc distance of the cutting stage and the processing stages in the circular path. These openings can then drop the blanks from the cutting stage into the subsequent processing stages after the slide plate pivots hack from the cutting stage. 
     According to a preferred embodiment of the device according to the invention, the slide plate can be clamped between the frames of the active elements of the processing stages of the upper and the lower parts upon closing in such a way that the active elements can process the blanks through the transfer openings. The slide plate thus becomes an integral part of the tool. 
     In another embodiment of the invention, the distance from the rotating axis of the slide plate to the far edge of the flat strip away from the slide plate is equal to the radius of the slide plate. This makes it possible to provide two mirror-imaged rotary slides in the travel direction of the flat strip opposite one another, having pivot directions opposite to one another for transferring the blanks and work pieces. The two rotary slides are disposed offset relative to one another in the direction of travel of the strip at a distance that is equal to about four times the arc distance of the cutting stage and the first processing stage in the circular path. 
     In another useful embodiment of the device according to the invention, the slide plate is disposed in a plane that allows horizontal pivoting of the slide plate with the transfer openings and the discharge opening directly over the respective active elements of the cutting stage and processing stages when the tool is open. In this way, the transfer openings and the discharge opening reach a position in which they can accommodate the blanks and grasp them for transport. 
     According to another embodiment of the invention, the slide plate is designed as a section of a circular disc provided with a dog at the periphery thereof facing the linear drive. The dog is connected to a carriage guided in a guide rail of the linear drive for purposes of executing the pivot motion of the slide plate about the rotating axis. 
     It is also an advantage that the slide plate comprises stop plates with stops at the frames of the active elements of the lower part for limiting the displacement of the linear drive to the arc distance between the fine blanking stage and the processing stages. 
     Another preferred embodiment of the device according to the invention provides that the transfer opening for the cutting stage is provided with claws for gripping the cut blank. The transfer openings for the processing stages are provided with transport masks for aligning and fixing the blanks. The opening fix discharging the finished work piece is provided with transport magnets for lifting and feeding to a chute. 
     According to another preferred embodiment of the device according to the invention, the discharge stage comprises an ejector fixed to the upper block of the upper part and located in the circular path. The ejector separates the finished work piece from the transport magnets of the discharge opening to a discharge chute. 
     In another preferred embodiment of the invention, the chute is disposed perpendicular to the circular path and parallel to the direction of travel of the strip. The chute is connected to at least one conveyor belt for removing the finished work pieces, the direction of removal of the conveyor belt being perpendicular to the chute. 
     The object is further achieved by transferring the blanks between the cutting stage and the processing stages when the tool is open using a reversible slide plate of a rotary slide. The plate includes transfer openings and a discharge opening. The rotary slide seizes the blank cut in the cutting stage by making a first pivot motion by an amount equal to the arc distance between the cutting stage and the processing stages and bringing it to the first processing stage in a second direction of identical arc distance opposite to the first pivot motion for processing. At the same time the blanks from the first processing stage and from the other processing stages are shifted to the next respective processing stage, and the finished work piece is discharged. 
     The method according to the invention proceeds substantially with the following steps: 
     a) holding the flat strip at the guide plate of the upper part when opening the tool, which is done by lowering the lower part; 
     b) pivoting the slide plate and the transfer openings and discharge opening thereof that lie in the circular path until the first transfer opening facing the cutting stage sits over the cutting stage, and the remaining transfer openings sit over the processing stages, and the discharge opening sits over the last processing stage, 
     c) ejecting the blanks from the cutting stage and the processing stages to the respective transfer openings and ejecting the finished work piece into the discharge opening, 
     d) pivoting the slide plate in a direction opposite to step b) with the blanks seized by the transfer openings until the slide plate releases the cutting stage, and the transfer openings with the blanks reach the next processing stages, 
     e) aligning and centering the blanks in the processing stages and accommodating the finished work piece in the discharge opening, and 
     f) clamping the slide plate between the frames of the active elements of the processing stages of the upper and lower parts simultaneously with the clamping of the strip material in the cutting stage when closing the upper and lower parts in the position reached according to step e), such that the active elements of the processing stages can process the blanks through the transfer openings, a new blank is cut in the cutting stage and the finished work piece is pushed out of the discharge opening by an ejector to a chute for removal. 
     One particular advantage is that the rotary slide is driven by a linear drive attached at the lower block and running tangentially coaxial to the circular path. The displacement of such linear drive matches the arc distance between the cutting and the processing stages in the circular path so that it is certain that the respective transfer and discharge opening always sits over or reaches the corresponding active elements, and so that the cutting stage is exposed for the next cutting process. 
     In another embodiment of the method according to the invention, rotary slides are used on both sides of the flat strip to transfer the cut and processed blanks. The pivot directions of the rotary slides are directed opposite to one another so that the entire width of the flat strip can be used for cutting. 
     In another preferred embodiment of the method according to the invention, the far side edges of the flat strip are guided over the periphery of the respective slide plate of the respective rotary slide, resulting in the rotary axes of the rotary slide being equal distances away from the flat strip, respectively. 
     Other advantages, features and details of the invention can be found in the following description with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in more detail below using an example of the manufacture of a fine-blanked part with internal cogging. It is understood that stamped or fine-blanked parts of other configurations are also covered by the invention. 
       Shown are: 
         FIG. 1  is a perspective view of a cutting and processing tool made of an upper part and a lower part in the closed state; 
         FIG. 2  is a perspective view of the bottom of the upper part of  FIG. 1 ; 
         FIG. 3  is a direct view of the bottom of the upper part according to  FIG. 2 ; 
         FIG. 4  is a perspective view of the lower part without flat strip and pusher slides in the closed state of the tool; 
         FIG. 5  is a direct view of the lower part in the open state of the tool according to  FIG. 4 ; 
         FIG. 6  is a perspective view of the lower part with rotary slides without flat strip in the closed state of the tool; 
         FIG. 7  is an enlarged view of the mounting of the flat strip on the upper part; 
         FIG. 8  is a perspective view of the slide plate as seen from the bottom side with claws and transport masks; 
         FIG. 9  is a direct view of the lower part with rotary slides pivoted underneath the belt strip in the open state of the tool without flat strip; 
         FIG. 10  is a direct view of the lower part with the rotary slides pivoted back in the closed state of the tool with the flat strip; and 
         FIG. 11  is a perspective representation of the lower part with rotary slides pivoted back in the closed state of the tool, with the blanks and the finished work piece associated with the transfer openings and the discharge opening. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
       FIG. 1  shows a cutting and processing tool  1  for cutting a blank  2  and processing it into a finished work piece  57  (see  FIG. 11 ). The cutting and processing tool  1  is made up essentially of an upper part  3  and a lower part  4 . The upper part  3  is immovably fixed, by way of the upper block  5  thereof, to a machine table, which is not further shown, and is fixed by way of the lower block  6  thereof by a ram of a press, such that the blank  2  is cut out upward from a flat strip  7  from below, which is to say, toward the upper part, in the cutting stage  8  and  8 . 1 . 
     The cutting and processing tool  1  has two cutting stages  8  and  8 . 1  separated from one another in the direction of travel R of the strip and a plurality of processing stages  9  to  12  and  9 . 1  to  12 . 1  per cutting stage, respectively, as well as one discharge stage each  13  and  13 . 1 . As shown in  FIGS. 2 and 3 , the upper active elements of the cutting stages  8  and  8 . 1 , for example a cutting punch  14  with internal punch insert  15  and embossing die  16 , are disposed in a guide plate  18  that sits atop a pressure plate  17 . The guide plate  18  is designed as a longitudinal polyhedral member  19  with two chamfers  20  and  20 . 1  with which each of the cutting stages  8  and  8 . 1  is associated, respectively. The upper active elements of cutting stages  8  and  8 . 1  in the guide plate  18  lie in circular paths K 1  and K 2  superimposed over center points P 1 /P 2 , respectively. The upper parts of the processing stages  9  to  12  and  9 . 1  to  12 . 1  are located in the circular path as separate upper components A, B. C and D in the form of circular segments and an ejector  58 . Components A through D each have separate pressure plates  21  and frames  22  in which the upper active elements  23  are held, for example an embossing bell, hole punch, ejector, setting, clamping and cogging punches. 
     The chamfer angle α at the guide plate  18  is matched with the central angle φ of the circular-segment components A, B, C and D such that it is equal to 0.5 times the mid-point angle φ. As a result component A sits directly against the chamfers  20  and  20 . 1  of the guide plate  18  next to cutting stages  8  and  8 . 1  in circular paths K 1  and K 2 , respectively. 
     As shown in  FIG. 2  in conjunction with  FIG. 7 , strip guides  24  are provided centered on each longitudinal side  44  of the upper block  5 . Each of the guides consists of rolls  25  separated by a distance equal to the width BR of the flat strip  7 . The guide plate  18  comprises strip holders  26 . As soon as the lower part executes a lowering motion to open the tool, the flat strip  7  is held in position by the strip guides  24  and the strip holders  26  so that a sufficient amount of free space results below the flat strip  7  for corresponding transfer operations. Reference is made at this point to  FIGS. 4 through 6 .  FIG. 4  represents the basic design of the lower part  4  in the closed state without the flat strip  7  and the rotary slide  37 , which will be described below. The lower part  4  comprises a lower block  6  on which are arranged the lower parts of the cutting stages  8  and  8 . 1  such as the cutting plate  27 , cutting plate inserts  28  and embossing dies  29 , as well as the lower active elements  35  of the processing stages  9  to  12  and  9 . 1  to  12 . 1 . 
     The cutting plate  27  is located in the center of the tool along with the guide plate  18  in the direction of travel R of the strip and has a longitudinal polyhedron-shaped member  30 , which is the same identical shape and form as the guide plate  18 , with two chamfers  31  and  31 . 1 , with which each of the lower parts of the cutting stage  8  and  8 . 1  is associated, respectively. The lower parts of the cutting stages  8  and  8 . 1  lie in the cutting plate  27  in a circular path K 3  and K 4  superimposed about the center point P 3 /P 4 . The lower active elements of processing stages  9  to  12  and  9 . 1  to  12 . 1  lie in the circular path as separate lower components E, F, G and H in the form of circular segments, as does a chute  32  of discharge stages  13  and  13 . 1 . Components E to H each comprise separate lower pressure plates  33  and lower frames  34  in which are accommodated the lower active elements  35 , such as an anvil, cutting plate inserts, punches for drawing, calibrating and supporting, as well as ejectors. 
     The chamfer angle α 1  on the cutting plate  18  is matched to the central angle φ 1  of the circular-segment lower components E, F, G and H in such a way that it is 0.5 times the central angle φ 1 . This causes component E to come to sit directly against the chamfers  31  and  31 . 1 , respectively, of the cutting plate  27  on the respective circular paths K 3  and K 4  along with the lower active elements of cutting stages  8  and  8 . 1 , respectively (see  FIG. 5 ). 
     A rotating axis DA of a slide plate  36  of a rotary slide  37  is positioned in perpendicular alignment with the center points P 1 /P 2  of the lower circular paths K 1 /K 2  and the center points P 3 /P 4  of circular paths K 3 /K 4 —as shown in  FIG. 6 . The rotating axis DA is held by an attachment plate  38  supported on the lower block  6 . The plate sits directly against the longitudinal sides LS of the cutting plate  27  above the chamfer  31  and  31 . 1 , respectively. 
     The rotating axis DA is a distance b away from the far side edge SR of the flat strip  7 , the distance being equal to the radius r of the slide plate  36  (see  FIG. 10 ). The rotary slide  37  is attached to the top side OS of the lower block  6  directly at the end face S. This slide comprises a linear drive  39  with a guide rail  40  and carriage  41  for executing a reversible pivoting motion of the slide plate  36  about the rotating axis DA in circular path K 1 /K 2  and K 3 /K 4  by an amount equal to the arc distance BA between the cutting stage  8  and  8 . 1  and the first processing stage  9  and  9 . 1  following the cutting stage  8  and  8 . 1 . Here, the guide rail  40  is disposed in such a way that it runs tangentially along the exterior periphery of the lower frames  34  which is coaxial to the circular path K 3 /K 4 . 
     Stops  42 . 1  and  42 . 2  are associated with the carriage  41  that runs along the guide rail  40  and are attached at the exterior periphery of the lower frames  34  at a distance which allows the path of displacement of the carriage  41  on the guide rail  40  to be limited to the arc distance BA. To accomplish this, the slide plate  36  is provided with corresponding stop plates  59  which are associated with the stops  42 . 1  and  42 . 2 . 
     The lower part of the discharge stage  13  and  13 . 1  includes the chute  32 , which is attached at the lower block  6 . The chute slopes downward from the chute entrance  43 , which lies in the circular path K 3 /K 4 , to a conveyor belt  45  and  45 . 1  running along the longitudinal sides  44  of the lower part  4  for taking away the finished work pieces. 
       FIG. 8  shows a perspective view of the slide plate  36 , designed as a section of a circular disk, which is able to pivot about the rotating axis DA and thereby about the center points P 1 /P 2  and P 3 /P 4  of the upper and lower circular paths K 1 /K 2  and K 3 /K 4 . The slide plate  36  is provided with transfer openings  46 ,  47 ,  48  and  49  and a discharge opening  50 . The transfer openings  46  to  49  and the discharge opening  50  lie in a circular path K 5  that coincides with circular paths K 1 /K 2  and K 4 /K 5 . The K 4 /K 5  distance between the openings is equal to the arc distance BA of the center point separations of the upper and lower active elements  23  and  35  of processing stages  9  to  12  and  9 . 1  to  12 . 1  on the circular paths. 
     The slide plate  36  has a protrusion  55  at the exterior periphery  51  thereof for attaching a dog  53  connected to the carriage  41  of the linear drive  39 . The dog executes a reversible pivoting motion between stops  42 . 1  and  42 . 2  about the rotating axis DA. 
     Claws  54  placed in the transfer opening  46  can seize the blank  2  cut in cutting stages  8  and  8 . 1  as soon as the transfer opening  46  arrives over cutting stage  8  and  8 . 1  by way of the pivot motion about the rotating axis DA. The transfer openings  47  to  49  are provided with transport masks  55  that enable the blanks  2  to be exactly fixed and aligned relative to the respective processing stage. The discharge opening  50  comprises transport magnets  56  that fix the finished work piece  58  and position it for discharge by way of the chute entrance  43 . 
     The method according to the invention is explained below with the aid of  FIG. 7, 9 through 11 . 
       FIG. 7  shows the position of the flat strip  7  on the upper block  5 . When the lower part  4  is lowered to open the tool  1 , the flat strip  7  is held by the strip holders  26  located on the guide plate  18  and the strip guides  24  attached to the upper block  5  in such a way that a sufficient amount of free space exists above cutting stages  8  and  8 . 1 . 
     The slide plates  36  have made a horizontal pivot motion—as shown in  FIG. 9 —under the flat strip  7  about rotating axis DA in the direction of the arrows in circular path K 5  in arc distance BA in a plane that lies directly above the active elements. Thus, the first transfer opening  46  facing the cutting stage  8  and  8 . 1  comes to lie above the active elements of the cutting stage  8  and  8 . 1 . At the same time, the transfer openings  47  to  49  have moved over the corresponding active element of the processing stages, and the discharge opening  50  has moved over the corresponding active elements of the processing stages  9  to  11  and  9 . 1  to  11 , and the discharge opening  50  has reached processing stage  12 . The protrusion  52  of slide plate  36  is then located at stop  42 . 2 , which is positioned at the outer periphery of the lower frames  34 . 
     In simultaneous fashion, the blank  2  cut in cutting stage  8  and  8 . 1 , the processed blanks  2  in the other processing stages  9  to  11  and  9 . 1  to  11 . 1 , and the finished work piece  57  are ejected to transfer openings  46  to  49 , and the finished work piece  58  is ejected to discharge opening  50 . 
     Slide plate  36  pivots back in a direction opposite to the first pivot motion by the arc distance BA in circular path K 5  together with seized blanks  2  and the finished work piece  57 . The slide plate  36  releases the cutting stage  8  and  8 . 1 . Transfer openings  46  to  49  with blanks  2  reach processing stages  9  to  12 . The blanks are placed in the correct position in processing stages  9  to  12  and  9 . 1  to  12 . 1  using the claws  54  and transport masks  55  located in the transfer openings  46  to  49 . The finished work piece  57  was transported simultaneous to this through the discharge opening  50  by way of the transport magnets  56  to the chute entrance  43  of the discharge stage  13  and  13 . 1 . 
       FIGS. 10 and 11  show the position of the transport strip  7  and slide plates  36  in a direct view and in a perspective view of the lower part  4  when the tool  1  is in the closed state. In this state, the flat strip  7  is clamped between the guide plate  18  of the upper part  3  and the cutting plate  27  of the lower part  5 , and the cutting process can proceed in cutting stage  8  and  8 . 1 . At the same time as the clamping of the flat strip  7  in cutting stage  8  and  8 . 1 , the slide plate  36  is also clamped between the lower frames  34  and the upper frames  22 . The transfer openings  46  to  49  and the discharge opening  50  have assumed a position such that the upper and lower active elements  23  and  35  can process the blanks  2  through the openings  46  to  50 , and the finished work piece  57  can be separated from the transport magnets  56  by way of the ejector  58 . At the same time, the cutting process in cutting stage  8  and  8 . 1  begins again, and the transfer process described above continues as described after the tool  1  is opened. 
     The flat strip  7  is guided over the center of the tool  1  in such a way that the respective far side edges SR of the flat strip  7  facing away from the slide plate  36  are guided over the periphery  51  of the slide plate  36  so that a rotary slide  37  can be used to transfer cut and processed blanks  2  and finished work pieces  57  on each side of the flat strip  7 , the pivoting directions of the slides being opposite directions to one another. The rotary slides  37  are offset in the direction BD of travel R of the strip by about four times the arc distance BA such that a sufficient cycle time is available for each processing cycle.