Patent Publication Number: US-3876084-A

Title: Apparatus for the movement of workpieces in a press

Description:
United States Patent [1 1 Munch et al.  
 [ APPARATUS FOR THE MOVEMENT OF WORKPIECES IN A PRESS [75] Inventors: Werner Munch; Wolfgang Michael,  
 both of Goeppingen, Germany [73] Assignee: L. Schuler GmhH, Goeppingen,  
 Germany 221 Filed: Mar. 15,1974  
  2| Appl. No.: 451,676  
 [30] Foreign Application Priority Data Mar 15, I9 3 Germany 2312861 52 us. Cl 214/t BB; l98/2l8 [5 l] Int. Cl. 865g 37/00 [58] Field of Search 214/1 BB, 1 BT, l B, l BS; I98/2l8 [56] eferences Cited UNITED STATES PATENTS 2,980,266 4/]96l Boros 2l4/l BB 3521.76] 7/l970 Wallis .l 2l4/l BB 3.753.489 8/l973 Tomioka 214/1 BB X 3162,05 l0/l973 Radobenko 2l4/l BB X Apr. 8, 1975 Primary ExaminerFrank E. Werner Attorney, Agent, or Firm-Craig &amp; Antonelli [57] ABSTRACT Apparatus for moving and handling workpieces in a press including a reciprocatable slide supporting workpiece handling means such as grippers as well as devices for operating same in response to relative movement of the devices and the slide. A mechanical drive connection between a main drive shaft and the slide is provided, which includes a slide crankshaft. The mechanism for moving the device with respect to the slide includes an operating shaft extending through and along the axis of the slide crankshaft. Cam and lever linkages are provided for controlling the respective rotation of the slide crankshaft and the operating shaft for the devices in such a manner that the slide is at a standstill position in respective opposite terminal positions and relative movement of the device and the slide takes place only when said slide is in said terminal position. Other preferred embodiments utilize coaxial slide crankshafts and operating shafts for devices which control the work holders or grippers wherein the devices are operated at other than the standstill end positions.  
 24 Claims, l0 Drawing Figures APPARATUS FOR THE MOVEMENT OF WORKPIECES IN A PRESS BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to an apparatus for the movement of workpieces in a press of the type which in cludes a slide reciprocatable by means of a slide crank and a connecting rod. This slide carries one or more devices for the operation of workpiece holding means. For example, the workpiece handling means may include one or more grippers which seize the workpiece and hold same during the conveying step or which pivot the workpiece. The workpiece handling means can also serve for lifting workpieces out of press tools. The workpieces can furthermore be withdrawn, by means of the workpiece handling means, from a stack and fed to the tools of a press, or conveyed in a gang or multiple-die press from one tool to the next, or withdrawn from a press tool and fed to a stack or another convey ing device.  
  In previously contemplated systems of the abovediscussed type, the workpiece handling means is actuated, for example, hydraulically, which is rather disadvantageous for structural and operational reasons, due to the movements of the slide, in which the workpiece handling means participates. For example, complex arrangements are required for sealing and feeding and discharging pressure medium to the hydraulic drive for the workpiece handling means.  
  The invention contemplates simplifying the drive of the device for operating the workpiece handling means and to render such drive safe in operation. The present invention also contemplates utilization of one or both of reciprocating and revolving movement in the drive of the devices.  
  More particularly, the present invention contemplates providing drive apparatus for the device or devices which derives movement from a device operating shaft coaxially disposed with respect to a slide crankshaft of the drive for the slide. The present invention further contemplates a preferred embodiment with a device operating crankshaft which is pivotal about the same axis as extends through a pin connecting the slide crank with a slide connecting rod, which slide connecting rod is connected for movement with the slide. The present invention also contemplates a preferred em bodiment where the transmission of movement from the device operating shaft to the device crankshaft is by way of a rack-and-pinion drive.  
  With the apparatus of the present invention, the device operating shaft and slide crankshaft are advantageously positioned for rotation about a common axis with a resultant simplification of the rotating mechanism therefor. Also, in the above-mentioned and below described preferred embodiments, the device crankshaft and the pin connecting the slide crankshaft to the slide connecting rod are also made coaxial with one another, with a consequent further simplification of the driving mechanisms and compactness of construction. Further, since the drive for the devices controlling the work handling means is by way of direct mechanical interconnection, rather than hydraulic drive means, problems regarding control and sealing of a pressure medium are avoided.  
  These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic sectional view along line II of FIG 2;  
  FIG. 2 is a part-sectional schematic top view, of the apparatus of the present invention;  
  FIG. 3 is a sectional schematic view along line lllIII of FIG. 2;  
  FIG. 4 is a sectional schematic view along line IV-IV of FIG. 2;  
  FIG. 5 is a schematic view showing an embodiment of the apparatus of the present invention in use on a multi-gang press; and  
  FIGS. 6-10 are diagrammatic views showing positions and movements of the slide and of the device of the apparatus of FIGS. 1-5 during a press stroke.  
 DETAILED DESCRIPTION OF THE DRAWINGS Throughout the various views, like reference numer als are used to depict like structures.  
  In a press frame or in a housing 1 attached thereto, a shaft 2 is disposed which makes one revolution per press stroke.  
  U.S. Pat. No. 3,707,908 discloses a transfer press arrangement of the type generally contemplated by the present invention, it being noted that shaft 2 of the present application could be connected to a driving connection such as indicated by reference numerals 8 and 10 in this patent. For further background information related to the environment of the present invention, see U.S. Pat. Nos. l,426,039&#39;, 2,352,632; 2,929,485; 3,105,399; 3,529,542; and 3,499,334. A cam disk 3 is connected for rotation with the shaft 2. This cam disk 3 drives, by way of a cam roller 4 in contact therewith, a rocking lever 6 in a swingably reciprocating motion. The rocking lever 6 is supported with respect to the housing I by means of a rocker arm 5. The free end 7 of the rocking lever 6 is hingedly joined to a rack 8 guided in the housing I for reciprocatory motion. A pinion 9 is arranged in the housing in meshing engagement with this rack 8. The pinion 9 is connected for rotation with a slide crankshaft 10 which, in turn, is connected at end 1] extending out of housing 1 for rotation with a slide crank 12. A slide connecting rod 13 is articulated to the free end of the slide crank 12 by pin 28. The other free end of slide connecting rod 13 is connected at a slide 14 (see FIGS. 5 to 10).  
  Another cam disk 15 is joined for rotation with the shaft 2. A rocking lever 18 is supported with respect to the housing I by means ofa rocker arm 17 and is driven to swing to and fro by this cam disk 15 via a cam roller 16 contacting the latter. The free end 19 of the rocking lever 18 is articulated to a rack 20 which is mounted to reciprocate in the housing I. Apinion 22 meshing with the rack 20 is connected to a device operating shaft 21, which shaft 21 is rotatably mounted in the slide crankshaft 10. A further pinion 24 is connected for rotation with the end 23 of shaft 21 extending out of the slide crankshaft 10. The pinion 24 and a further pinion 26, are in meshing engagement with a rack 25 mounted in the slide crank 12 to be reciprocatable therein. Pinion 26 is coaxial with and rotatable with respect to pin 28 of slide crank 12. Rotation pinion 26 effects movement of device operating crankshaft 27.  
  The operating crankshaft 27 carries an operating crank 29 for rotation therewith. A device connecting rod 31 is connected to crankshaft 27 by means of a crankpin 30. The connecting rod 31 is connected to a device 32 which is reciprocatable on the slide 14. The reciprocating motion of the device 32 with respect to slide 14 is translated into the motion required to actuate workpiece handling means such as grippers and the like. The length a of this relative motion of device 32 and slide 14, FIGS. 6 to 10, is equal to twice the length of the operating crank 29.  
  The gear train (2-6, 8-10, 12, 13) for imparting reciprocating motion to the slide 14 is designed (appropriately curved cam surface) to effect a standstill terminal positions as illustrated in FIGS. 6, 7, 9 and 10.  
  The gear train (2, 27, 29-31) for imparting relative movement of device 32 and slide 14 is designed (appropriately curved sam surface on 15 and in relationship to cam surface on 3) so that such relative movement only takes place when the slide 14 is at one of the respective terminal positions.  
  Therefore, the device 32 on the slide 14 does not exe cute any motions, either, during the reciprocating movements of the slide; the distance a between the two end positions of the device 32 on the slide 14 remains the same during the reciprocating motions of the slide.  
  As schematically illustrated in FIGS. 6 to 10, the slide 14 and the device 32 thereon execute the following motions during a swinging movement ofthe slide crank 12 of l80.  
  FIGS. 6, 7: The slide crank 12 has swung into the lefthand terminal position. During this motion, the device 32 on the slide 14 has retained its end position shown in full lines. After reaching the left-hand end position of the slide 14, the device operating crank 29 swings from its right-hand end position into its left-hand end position, whereby the device 32 on the slide 14 is moved by the path length a into the left-hand end position shown in dot-dash lines. Thereby. the device 32 is operated and the workpiece is, for example, gripped, released. lifted out of a tool. or otherwise manipulated (through the relative movement of device 32 and slide 14).  
  FIG. 8: After this movement of the device 32 has been completed, the latter remains in its position on the slide 14 until the slide 14 has returned into the righthand final position (FIG. 9). Intermediate positions of the slide 14 and of the device 32 between the two end positions of the slide are shown in FIG. 8. After reaching the right-hand end position of the slide 14 (FIG. 9), the operating crank 29 also executes a pivoting motion by 180, so that the device 32 returns from its left-hand end position, shown in dot-dash lines, into the righthand end position, shown in full lines (FIG. 10). By this movement of the device 32, the work handling means is again actuated along the lines of seizing, releasing, lifting, or other manipulation of the workpiece. After this motion of the device 32 has been terminated, the slide 14 returns, by pivoting the slide crank 12, from the righthand end position according to FIG. 10 into the left-hand end position according to FIG. 6. During this motion, the device 32 is at a standstill on the slide 14.  
  The required motions are imparted to the slide 14 by the gear train 2-6, 8-10, 12, 13, and to the device 32 by the gear train 2, 15, 18, 20-22, 24-31.  
  The cam disk 3 for the slide movement is designed so that the slide 14 is at a standstill for the desired time period in the two end positions. Furthermore, the cam disk 15 for the movement of the device 32 is designed so that the device 32 reciprocates on the slide 14 only in the end positions of the slide. Therefore, the cam disk 15 also has the effect that the device 32 does not execute any motions with respect to the slide 14 during the reciprocating movements of the slide.  
 In the embodiment of this invention according to FIG. 5, two sets of apparatus as described and illustrated with respect to FIGS. 1 to 4 and 6 to 10 are provided in opposition to each other in the interior of a gang or multiple-die press indicated schematically by four columns 33 of the press frame thereof. Each of the two slides 14 is equipped with eight devices 32 connected to one another by means of rods 34, so that the devices 32&#39; directly driven by the operating connecting rods 31 transmit their motions to the remainder of the devices 32. The workpiece handling means which are operated, for example, by the devices 32, 32&#39; are indicated schematically by opened jaws 35 of gripper bars, the legs of which are disposed one on top of the other, but are placed into the plane of the drawing to simplify the illustration. The jaws 35 seize a piece of sheet metal (workpiece) and convey same from one tool of the gang press to the next. After reaching a left-hand final position, for example, the jaws are opened by a corresponding movement of the devices 32, thereby releasing the sheet-metal piece, after which they return on the slides 14 onto the right-hand end position, again seize the piece of sheet metal by a corresponding, opposite movement of the devices 32, and execute, together with the slides 14, the next conveying motion of the piece of sheet metal, and so forth.  
  The present invention also contemplates other non illustrated embodiments, wherein, instead of swinging to and fro in an arc of 180, the slide crank 12 revolves, either without any standstill at respectively I or after coming to a standstill after Embodiments are also contemplated wherein the slide crank 12 can swing to and fro in the end positions without coming to a respective standstill. Embodiments are also contemplated where the device 32 is reciprocated on the slide 14 during the motions of the slide, with or without being arrested. These motions can be produced, as shown in the preferred embodiments, by an appropriate construction of the cam drives 3-6 and/or 15-18, or by articulated drives. Since details of gripper assemblies and other work handling means operable in response to relative movement of a device such as schematically illustrated at 32 and a slide such as schematically depicted at 14, would be known to one skilled in the art to the extent that, one so skilled, given the present disclosure and the state of the art, could construct and use same, details thereof have not been included herein so as not to obscure the present invention.  
  While we have shown and described several embodiments in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to those skilled in the art and we therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.  
 We claim:  
  1. Apparatus for moving workpieces in a machine tool comprising:  
 a slide,  
 slide moving means for moving said slide,  
 workpiece handling means including means for holding workpieces for movement with said slide,  
 a device carried by said slide for controlling changes in the operative condition of said workpiece handling means in response to relative movement of said slide and said device,  
 and device moving means for moving said device relative to said slide to effect changes in the operative condition of said workpiece handling means,  
 said slide moving means including a slide crankshaft supporting a slide crank which is operatively connected to said slide to move said slide upon rotational movement of said slide crankshaft and slide crankshaft rotating means for imparting rotational movement to said slide crankshaft,  
 said device moving means including a device operating shaft which is coaxial with and rotatable with respect to said slide crankshaft and device operating shaft rotating means for rotating said device operating shaft with respect to said slide crankshaft.  
  2. Apparatus according to claim 1, wherein said device moving means includes a device crankshaft supporting a device crank which is operatively connected to said device to move said device with respect to said slide upon rotation of said device crankshaft, said device crankshaft being spaced from said device operating shaft.  
  3. Apparatus according to claim 2, wherein said slide crank is operatively connected to said slide by a slide connecting rod pivotally supported at said slide crank, and wherein the pivotal axis of the connectidn between said slide connecting rod and slide crank is coaxial with the axis of rotation of said device crankshaft.  
  4. Apparatus according to claim 3, wherein said device moving means includes a rack carried by said slide crank and pinions at said device operating shaft and device crankshaft for transferring rotation of said device operating shaft to said device crankshaft.  
  5. Apparatus according to claim 4, wherein said slide crankshaft and said device operating shaft are disposed one inside the other.  
  6. Apparatus according to claim 5, wherein a device connecting rod is provided for transmitting movements of said device crankshaft to said device.  
  7. Apparatus according to claim 6, wherein said slide crankshaft rotating means and said device operating shaft rotating means include a common drive shaft.  
  8. Apparatus according to claim 7, wherein said slide crankshaft rotating means has means for rotating said slide crankshaft in an oscillatory manner in respective opposite directions between respective rotative end positions.  
  9. Apparatus according to claim 1, wherein said slide crankshaft and said device operating shaft are disposed one inside the other.  
  10. Apparatus according to claim 9, wherein a device connecting rod is provided for transmitting movements of said device crankshaft to said device.  
  11. Apparatus according to claim 10, wherein said machine tool is a multiple-die press, and wherein a plurality of said devices are connected to said device connecting rod for movement together with respect to said slide which extends adjacent a plurality of dies of said press.  
  12. Apparatus according to claim 11, wherein said workpiece handling means includes gripper means for selectively gripping and releasing workpieces in response to relative movement of said devices and said slide.  
  13. Apparatus according to claim 9, wherein said slide crankshaft rotating means has means for rotating said slide crankshaft in an oscillatory manner in respective opposite directions between respective rotative end positions.  
  14. Apparatus according to claim 1, wherein said slide crankshaft rotating means and said device operat&#39; ing shaft rotating means include a common drive shaft.  
  15. Apparatus according to claim 1, wherein said slide crankshaft rotating means has means for rotating said slide crankshaft in an oscillatory manner in respective opposite directions between respective rotative end positions.  
  16. Apparatus according to claim 15, wherein said rotative end positions are less than 360 apart.  
  17. Apparatus according to claim 15, wherein at least one of said slide crankshaft rotating means and said device operating shaft rotating means include articulated coupling device means.  
  18. Apparatus according to claim 1, wherein said slide crankshaft rotating means includes a rocking lever connected to a rack-and-pinion drive, and wherein said drive operating shaft rotating means includes a further rocking lever connected to a further racleand-pinion drive.  
  19. Apparatus according to claim 18, wherein said slide crankshaft rotating means includes a cam engageable to move said rocking lever, and wherein said device operating shaft rotating means includes a further cam engageable to move said further rocking lever.  
  20. Apparatus according to claim 19, wherein said cam and said further cam are mounted on a common drive shaft for rotation together therewith.  
  21. Apparatus according to claim 20, wherein said slide crankshaft and said device operating shaft are disposed one inside the other.  
  22. Apparatus according to claim 21, wherein said device moving means includes a device crankshaft supporting a device crank which is operatively connected to said device to move said device with respect to said slide upon rotation of said crankshaft, said device crankshaft being spaced from said device operating shaft.  
  23. Apparatus according to claim 20, wherein said cams are configured such that said device is moved with respect to said slide only when said slide is in an end rest position.  
  24. Apparatus according to claim 18, wherein at least one of said slide crankshaft rotating means and said device operating shaft rotating means include articulated coupling drive means.