JP2017164809A - Crowning method for press brake and press brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crowning method and a press brake, in which, upon executing crowning of a lower table, the crowning is executed by rotating eccentric shafts via a power up mechanism.SOLUTION: There is provided a crowning method for a press brake, in which a front plate 11 and a back plate 13 are arranged at front side or back side of a lower table 5 supported on right and left side frames 3L, 3R in a press brake 1, and the crowning is executed by rotating each of eccentric shafts 23 arranged on the lower table 5 with an interval in lateral direction. A power up mechanism 41 is provided between an actuator 31 for rotating each of the eccentric shafts 23 and each of the eccentric shaft 23. Output from the actuator 31 is strengthened by the power up mechanism 41 and transmitted to each of the eccentric shafts 23 so as to execute crowning by rotating each of the eccentric shafts 23.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a press brake crowning method and a press brake, and more specifically, when an eccentric shaft is rotated to perform crowning of a lower table, the eccentric shaft is increased by a booster mechanism (a booster mechanism). The present invention relates to a crowning method for rotating and crowning and a press brake.

  As is well known, the press brake includes C-shaped left and right side frames. A lower table is provided at the front lower portion of the side frame. An upper table facing the lower table is provided at the front upper part of the side frame so as to be movable up and down. In the press brake having the above-described configuration, a plate-like workpiece is placed and positioned on the lower mold mounted on the lower table. Then, the workpiece is bent by the cooperation of the upper and lower molds by pressurizing the workpiece with an upper mold provided in the upper table.

  When the workpiece is bent as described above, the left and right ends of the lower table are fixed to the left and right side frames, and the left and right ends of the upper table are supported by the side frames so as to be movable up and down. is there. Therefore, the central portions of the upper and lower tables tend to bend in directions away from each other due to the reaction force when the workpiece is bent. Therefore, when the workpiece is bent, the bending angle near the center of the workpiece becomes sweeter (larger) than the bending angles near the left and right ends, and the workpiece becomes a boat shape.

  Therefore, when the workpiece is bent, the center of the lower table is bent upward corresponding to the upward bending of the upper table so that the upper and lower tables are kept parallel. That is, crowning is being performed. Since a large force is required to bend the central portion of the lower table upward, a hydraulic cylinder has been used as the actuator.

  When the crowning operation is performed using the hydraulic cylinder as described above, the hydraulic system is likely to become large, and the maintenance and management of the overall configuration is troublesome, and there is a problem of the temperature rise of the hydraulic oil. Therefore, it has been proposed to perform the crowning by rotating the eccentric shaft (see, for example, Patent Documents 1 and 2).

JP 2000-343127 A JP2015-178131A

  The configurations described in Patent Documents 1 and 2 are configurations in which the output shaft and the eccentric shaft of the motor are directly connected via a coupling. Therefore, a large motor is used as the motor, and it has been desired to reduce the size of the motor in order to save energy and make the overall configuration compact.

  The present invention has been made in view of the problems as described above, and includes a front plate and a rear plate before and after a lower table attached to the lower side of the left and right side frames in a press brake, and a lower mold provided in the lower table A crowning method in a press brake comprising an upper table provided with an upper mold for bending a plate-like workpiece in cooperation with the upper side of the left and right side frames, wherein the upper table is freely movable up and down. A force-increasing mechanism is provided between an actuator for rotating an eccentric shaft provided in the lower table to perform table crowning and the eccentric shaft, and an output of the actuator is increased by the force-increasing mechanism to increase the eccentricity. The shaft is transmitted to the shaft, and the eccentric shaft is rotated to perform crowning.

  In addition, the front plate and the rear plate are arranged before and after the lower table supported by the left and right side frames in the press brake, and a plurality of eccentric shafts provided in the lower table are rotated apart from each other in the left-right direction. A crowning method of a press brake for performing crowning, comprising a force increasing mechanism between an actuator for rotating each eccentric shaft and each eccentric shaft, and increasing an output of the actuator by the force increasing mechanism. It transmits to each said eccentric shaft, and rotates each said eccentric shaft and performs crowning.

  Also, in the crowning method of the press brake, the force-increasing mechanism includes each lever member that extends in a direction intersecting with the axis of each of the left and right eccentric shafts and is provided integrally with each of the eccentric shafts, Actuators that push and pull each link member pivotally connected to the tip of the lever member and the base end side of each link member pivotally connected in a direction intersecting the longitudinal direction of each link member When the eccentric shafts provided separately from each other in the left and right directions are rotated, the eccentric shafts are synchronized and rotated in opposite directions to perform crowning.

  Also, the front plate and the rear plate are arranged on the front and rear of the lower table supported by the left and right side frames in the press brake, and the eccentric shaft mechanisms provided on the lower table are rotated apart from each other in the left-right direction. A method of crowning a press brake for performing crowning, comprising a force-increasing mechanism between each actuator for individually rotating each eccentric shaft mechanism and each eccentric shaft mechanism, and outputting an output of each actuator The force is increased by each force increasing mechanism and transmitted to each eccentric shaft mechanism, and the respective eccentric shaft mechanisms are individually rotated to perform crowning.

  Further, in the crowning method of the press brake, each eccentric shaft mechanism provided separately in the left-right direction has a configuration in which a pair of left and right eccentric shafts are rotatably provided, and the pair of left and right eccentric shafts by the respective force increasing mechanisms. When rotating the shaft, the eccentric shafts are synchronized and rotated in opposite directions to perform crowning.

  In addition, front plates and rear plates are provided on the front and rear of the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake provided with an upper table having an upper mold to be moved up and down on the upper side of the left and right side frames, and an eccentric shaft for crowning the lower table can be rotated to the lower table. And a force-increasing mechanism for increasing the output of the actuator and transmitting it to each eccentric shaft between the actuator for rotating the eccentric shaft and the eccentric shaft.

  In addition, front plates and rear plates are provided on the front and rear of the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake having an upper table with an upper mold to be moved up and down on the upper side of the left and right side frames, wherein left and right eccentric shafts for crowning the lower table are separated in the left-right direction The lower table is rotatably provided, and is provided with a force-increasing mechanism that increases the output of the actuator and transmits it to each eccentric shaft between the actuator for rotating the eccentric shaft and each eccentric shaft. It is what.

  In the press brake, the force-increasing mechanism is provided extending in a direction intersecting with the axis of each of the left and right eccentric shafts, and is provided integrally with each eccentric shaft, Each link member has a distal end portion pivotally connected to the distal end portion of each lever member, and the proximal end portion of each link member pivotally connected to each other is pushed and pulled by the actuator.

  In the press brake, each of the left and right eccentric shafts has a plurality of eccentric shafts arranged in parallel in the left-right direction, and the plurality of eccentric shafts provided in parallel rotate in the same direction in synchronization. It is the composition which is done.

  In addition, front plates and rear plates are provided on the front and rear of the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake having an upper table having an upper mold to be moved up and down on the upper side of the left and right side frames, wherein left and right eccentric shaft mechanisms for crowning the lower table are separated in the left-right direction. The lower table is rotatably provided, and in order to individually operate each eccentric shaft mechanism, the output of each actuator is increased between each individually provided actuator and each eccentric shaft mechanism to A force-increasing mechanism that individually transmits to each eccentric shaft mechanism is provided.

  In the press brake, the force-increasing mechanism is a toggle mechanism.

  In the press brake, the eccentric shaft mechanism includes a plurality of eccentric shafts arranged in parallel in the left-right direction, and the toggle mechanism includes each lever provided integrally with each eccentric shaft provided in parallel. The distal end portion of each member is provided with the distal end portion of each link member pivotally connected, and the base end side portion pivotally connected to each other of the link members is pushed and pulled by the actuator.

  Further, in the press brake, the actuator is a servo motor, and a member that pushes and pulls the pivotally connected portion of each link member is a ball nut that is reciprocally screwed to a ball screw rotated by the servo motor. is there.

  In the press brake, the ball screw is disposed in a plane parallel to the plate surface of the lower table, and the rotation shaft of the servo motor is disposed in a plane parallel to the plate surface of the lower table. is there.

  In addition, front plates and rear plates are provided on the front and back of the lower table attached to the lower side of the left and right side frames in the press brake. A press brake having an upper table with an upper mold to be moved up and down on the upper side of the left and right side frames, wherein left and right eccentric shafts for crowning the lower table are separated in the left-right direction The lower table is rotatably provided, and the free end side of each intensifying link mechanism in which the base end side is connected to the left and right eccentric shafts is connected to both end sides of a connecting member that can be extended and contracted, and the connecting member The connecting member is provided with an actuator for performing the telescopic operation.

  In the press brake, the connecting member includes a ball screw mechanism at both ends, and an actuator that individually operates the ball screw mechanisms at both ends.

  Further, in the press brake, the intensifying link mechanism includes a distal end portion of each link member pivotally connected to a distal end portion of each lever member having a proximal end portion connected to each eccentric shaft provided adjacent thereto. The one link member in each link member is provided longer than the other link member, and the base end side of the other link member is pivotally connected to an intermediate position in the one link member, and the one link The end of the connecting member is connected to the base end side of the member.

  In addition, front plates and rear plates are provided on the front and rear of the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake having an upper table with an upper mold to be moved up and down on the upper side of the left and right side frames, wherein left and right eccentric shafts for crowning the lower table are separated in the left-right direction The lower table is provided rotatably, and is provided with a force-increasing mechanism that increases the output of the actuator and transmits it to each eccentric shaft between the actuator and the eccentric shaft for rotating each eccentric shaft, In addition, biasing means for assisting the operation of the actuator when the eccentric shaft is rotated by the actuator is provided.

  In addition, front plates and rear plates are provided on the front and rear of the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake having an upper table with an upper mold to be moved up and down on the upper side of the left and right side frames, wherein left and right eccentric shafts for crowning the lower table are separated in the left-right direction The lower table is rotatably provided, and the free end side of each intensifying link mechanism in which the base end side is connected to the left and right eccentric shafts is connected to both ends of the extendable connecting member. It is configured to have a ball screw mechanism on both ends, and has an actuator that individually operates the ball screw mechanisms on both ends, and each actuator is operated by each actuator. When that includes a biasing means for assisting the operation of each actuator.

  In addition, front plates and rear plates are provided on the front and back of the lower table attached to the lower side of the left and right side frames in the press brake. A press brake having an upper table with an upper mold to be moved up and down on the upper side of the left and right side frames, wherein left and right eccentric shafts for crowning the lower table are separated in the left-right direction The lower table is rotatably provided, and both end sides of an extendable connecting member are connected to the free end side of each intensifying link mechanism in which the base end side is connected to the left and right eccentric shafts. An actuator for rotating the provided ball screw mechanism is provided in the connecting member, and when each of the force-increasing link mechanisms is operated by the actuator via the connecting member, Biasing means for assisting the operation of the actuator is provided in each energizing linkage.

  In the press brake, the urging means is a compression spring.

  According to the present invention, when the eccentric shaft is rotated to perform press brake crowning, the output of the actuator is increased by interposing the force increasing mechanism between the actuator for rotating the eccentric shaft and the eccentric shaft. To communicate. Therefore, the actuator can be reduced in size and size, and energy can be saved.

1 is an explanatory perspective view schematically showing an overall configuration of a press brake according to an embodiment of the present invention. It is the isometric view explanatory drawing which looked at the structure which performs crowning of a lower table from the back surface (rear surface) of the lower table. It is the isometric view explanatory drawing which looked at the cross section of a part of eccentric shaft unit concerning a 1st embodiment, and was seen from the back. It is action explanatory drawing which shows the structure of the boost (boost) mechanism of 1st Embodiment for rotating the eccentric shaft with which the eccentric shaft unit was equipped. It is action explanatory drawing which shows the structure of the boost (boost) mechanism of 2nd Embodiment for rotating the eccentric shaft with which the eccentric shaft unit was equipped. It is a back surface (rear surface) perspective explanatory drawing of the lower table which shows the structure which concerns on 3rd Embodiment. The lower table which concerns on 3rd Embodiment is shown, (A) is plane explanatory drawing, (B) is a back surface (rear surface) explanatory drawing. It is a back perspective explanatory view showing the composition of the lower table concerning a 4th embodiment. The structure of the lower table which concerns on 5th Embodiment is shown, (A) is a plane explanatory drawing, (B) is a back surface explanatory drawing. FIG. 10 is a perspective explanatory view of the toggle mechanism shown in FIG. 9. FIG. 10 is an explanatory plan view of the toggle mechanism shown in FIG. 9. FIG. 10 is an explanatory plan view of the toggle mechanism shown in FIG. 9. It is back surface explanatory drawing which shows the structure of a toggle mechanism part. It is a back perspective explanatory view showing the composition of the lower table concerning a 6th embodiment. FIG. 15 is an explanatory rear view illustrating the configuration of the toggle mechanism illustrated in FIG. 14. FIG. 15 is an explanatory rear view illustrating an operation state of the toggle mechanism illustrated in FIG. 14. FIG. 15 is an explanatory rear view illustrating an operation state of the toggle mechanism illustrated in FIG. 14. It is a back surface explanatory view showing the composition of the lower table concerning a 7th embodiment. The structure of the lower table which concerns on 7th Embodiment is shown, (A) is a plane explanatory drawing, (B) is a back surface explanatory drawing. It is back surface explanatory drawing which shows the operation state of a toggle mechanism. It is back surface explanatory drawing which shows the operation state of a toggle mechanism.

  Hereinafter, the press brake according to the embodiment of the present invention will be described with reference to the drawings. The overall configuration of the press brake is a well-known configuration. For easy understanding, the overall configuration of the press brake will be briefly described.

  Referring to FIG. 1, a press brake 1 according to an embodiment of the present invention includes C-shaped left and right side frames 3L and 3R on both sides in the left-right direction (X-axis direction). The left and right ends of the plate-like lower table 5 are supported on the lower portions on the front side of the side frames 3L, 3R. The left and right ends of the upper table 7 as a ram are supported on the front upper portions of the side frames 3L and 3R so as to be movable up and down. In order to move the upper table 7 up and down, ram lifting and lowering operation devices 9L and 9R each composed of, for example, a hydraulic cylinder or a ball screw mechanism are mounted on the front upper portions of the side frames 3L and 3R.

  In the above configuration, a plate-like workpiece is placed and positioned on a lower mold (not shown) mounted on the lower table 5. Then, by lowering the upper table 7, the work is pressurized with an upper mold (not shown) mounted on the upper table 7. In this way, when the workpiece is pressurized, the workpiece is bent by the cooperation of the upper and lower molds.

  As described above, when the workpiece is bent by the upper and lower molds mounted on the upper and lower tables 7 and 5, the central portions in the left and right directions of the upper and lower tables 7 and 5 are separated from each other by the reaction force. Tend to curve. Therefore, in order to keep the upper and lower molds mounted on the upper and lower tables 7 and 5 in a parallel state and bend the workpiece, the central portion in the left and right direction of the lower table 5 is curved in a convex shape upward. Crowning is performed.

  More specifically, the lower table 5 is attached to front lower portions of the side frames 3L and 3R via bolts or the like (not shown). A front plate 11 and a rear plate 13 are provided before and after the lower table 5, respectively. The front plate 11, the lower table 5, and the rear plate 13 are integrally provided via left and right pivots 15L and 15R penetrating the front plate 11 in the front-rear direction.

  A substantially rectangular through hole that penetrates the front plate 11, the lower table 5, and the rear plate 13 in the front-rear direction at a symmetrical position with the center position in the left-right direction (X-axis direction) in the press brake 1. 17L and 17R are formed. In the through holes 17L and 17R, an eccentric shaft for pressing the lower table 15 upward with respect to the front plate 11 and the rear plate 13 to bend the central portion of the lower table 15 in a convex shape upward. Units (eccentric shaft mechanisms) 19L and 19R are internally provided.

  More specifically, as shown in FIG. 3, the eccentric shaft units 19L and 19R have front and rear bearing blocks whose movement in the vertical direction is restricted in the through holes 17L and 17R in the front plate 11 and the rear plate 13, respectively. 21F and 21B are provided apart from each other in the front-rear direction. In other words, the plate thickness of the front and rear bearing blocks 21F and 21B is substantially equal to the plate thickness of the front plate 11 and the rear plate 13. The front-rear direction interval is substantially equal to the front-rear direction interval between the front plate 11 and the rear plate 13. Front and rear ends of a pair of left and right eccentric shafts 23 having the same configuration are rotatably supported on the bearing blocks 21F and 21B.

  More specifically, the bearing blocks 21F and 21B are each provided with a bearing flange 25, and both front and rear ends of the eccentric shaft 23 are rotatably supported by the bearing flange 25. Between the front and rear bearing flanges 25, the eccentric shaft 23 is provided with a large-diameter eccentric portion 23E. A lift block 29 is supported on the eccentric portion 23E via a plurality of bearings 27.

  The elevating block 29 is disposed between the front and rear bearing blocks 21F and 21B so as to be movable up and down. A pressing plate 29 </ b> A that presses the upper surface of the through holes 17 </ b> L and 17 </ b> R formed in the lower table 5 is provided on the upper surface of the elevating block 29. The lifting block 29 is restricted from rotating so as not to follow when the eccentric shaft 23 rotates. Between the lower surface of the elevating block 29 and the lower surfaces of the through holes 17L and 17R in the lower table 5, there is provided a clearance that allows the lower table 5 to move up and down by the rotation of the eccentric shaft 23. It is what.

  As understood from the above configuration, when the eccentric shafts 23 provided in the eccentric shaft units 19L and 19R are rotated in the same direction, the elevating blocks 29 move up and down with respect to the front and rear bearing blocks 21F and 21B. become. Here, since the bearing blocks 21F and 21B in the eccentric shaft units 19L and 19R are in a state in which the vertical movement is restricted by the front plate 11 and the rear plate 13, the front plate 11 and the rear plate are moved when the lifting block 29 is moved upward. The lower table 5 is pressed upward against the plate 13. That is, a crowning operation is performed.

  By the way, since the eccentric shaft units 19L and 19R are provided with a plurality of eccentric shafts 23, the load when the crowning is performed by pressing the lower table 5 upward is shared by the eccentric shafts 23. Is. Therefore, each eccentric shaft 23 can be made thinner compared to the case where a single eccentric shaft is used, and the vertical dimension can be suppressed to achieve a compact size. Note that the left and right eccentric shaft units 19L and 19R provided in the left and right through holes 17L and 17R have a symmetrical configuration and their operating directions are opposite to each other.

  In order to operate the left and right eccentric shaft units 19L, 19R in synchronization, as shown in FIG. 2, an operating device (actuator) 31 is provided on the rear surface of the rear plate 13. More specifically, a support bracket 33 is attached to the rear surface of the rear plate 13, and a servo motor 35 is attached to the support bracket 33. The support bracket 33 is provided with a ball screw 37 that is rotated by the servo motor 35 vertically and rotatably. A nut member 39 is screwed onto the ball screw 37 so as to be movable up and down. Therefore, when the servo motor 35 is rotated forward and backward, the ball screw 37 is rotated forward and backward, and the nut member 39 is moved up and down.

  In order to rotate the eccentric shafts 23 in the left and right eccentric shaft units 19L and 19R, boosting mechanisms (boost mechanisms) 41L and 41R are provided between the operating device 31 and the eccentric shafts 23, respectively. Yes. The force-increasing mechanism 41 has a function of increasing the output of the operating device 31 and transmitting it to the eccentric shafts 23. In the present embodiment, the force-increasing mechanism 41 is constituted by a toggle mechanism. It is configured.

  That is, as shown in FIG. 4, long levers extending in the direction intersecting (orthogonal to) the axis of each eccentric shaft 23 at the rear end of each eccentric shaft 23 in the left and right eccentric shaft units 19L and 19R. The base end portion of the member 43 is fixed integrally. The distal end portions of the lever members 43 in the eccentric shaft units 19L and 19R are pivotally connected to the connecting member 47 via hinge pins 45. That is, the tip end portions of the lever members 43 are pivotally connected to each other via the connecting member 47.

  The distal ends of the left and right link members 49L and 49R are pivotally connected to the hinge pins 45 of the left and right force-increasing mechanisms 41L and 41R. The base end portions of the left and right link members 49L and 49R are pivotally connected to each other via a pivot 51. A push-pull member 53 that pushes and pulls the pivot 51 in the upward direction, that is, the direction intersecting the longitudinal direction of the link members 49L and 49R is pivotally attached to the pivot 51. As shown in FIG. 2, the push-pull member 53 is attached to the nut member 39 in the operating device 31 as an example of an actuator.

  Therefore, when the servo motor 35 is driven and the ball screw 37 is rotated forward and backward to move the nut member 39 up and down, the push-pull member 53 is moved up and down integrally. As can be understood from FIG. 4, when the push / pull member 53 is lowered from the raised position, the depression angles of the link members 49L and 49R of the left and right link members 49L and 49R are gradually increased. In other words, the distal end portions of the lever members 43 in the left and right eccentric shaft units 19L and 19R are pressed and rotated outwardly, in other words, the distal end portions of the lever members 43 are separated from each other.

  As described above, the lever members 43 in the left and right eccentric shaft units 19L and 19R are rotated. Accordingly, the eccentric shafts 23 in the left and right eccentric shaft units 19L and 19R are rotated in opposite directions in synchronization. Thus, when each eccentric shaft 23 is rotated, each eccentric shaft 23E in each eccentric shaft 23 is gradually raised from the lowered position. Therefore, the pressing plate 29A provided in each lifting block 29 in the left and right eccentric shaft units 19L, 19R presses the lower table 5 upward to perform crowning.

  As described above, when the eccentric shafts 23 are rotated to perform crowning, the eccentric shafts 23 are rotated via the force-increasing mechanisms 41L and 41R configured by a toggle mechanism. Therefore, when the eccentric shaft 23 is rotated, the output of the operating device 31 is increased to rotate. Therefore, the operating device 41 can be reduced in size and size. The operating device (actuator) for moving the push-pull member 53 up and down (push-pull) is not limited to the configuration as described above, and for example, a fluid pressure cylinder or the like can be used.

  By the way, in the said description, the case where each eccentric shaft 23 with which left-right eccentric shaft unit 19L, 19R was equipped was operate | moved by the common actuator 31 was demonstrated. However, the eccentric shafts 23 in the left and right eccentric shaft units 19L and 19R can be individually operated by separate operating devices as shown in FIG.

  Referring to FIG. 5, left and right eccentric shaft units 55L and 55R corresponding to the left and right eccentric shaft units 19L and 19R described above are housed in the through holes 17L and 17R in the same manner as the eccentric shaft units 19L and 19R. Is. The eccentric shaft units 55L and 55R are provided with left and right eccentric shafts 57L and 57R corresponding to the eccentric shaft 23, respectively. The eccentric shafts 57L and 57R are configured to be bilaterally symmetric and are configured to rotate in opposite directions to each other, which is different from the configuration of the eccentric shaft units 19L and 19R described above. However, since the other configuration is the same configuration and performs the same function, a detailed description of the eccentric shaft units 55L and 55R will be omitted.

  The base ends of the left and right lever members 59L and 59R corresponding to the lever member 43 are integrally attached to the eccentric shafts 57L and 57R provided in the left and right eccentric shaft units 55L and 55R. Further, the distal ends of the link members 61L and 61R corresponding to the link members 49L and 49R are pivotally connected to the distal ends of the lever members 59L and 59R via hinge pins 63, respectively. The base ends of the link members 61L and 61R are pivotally connected to the push / pull member 67 via a pivot 65. The push / pull member 67 corresponds to the push / pull member 53 described above. Since the structure of the actuator (actuator) 69 that moves the push-pull member 67 up and down is the same as that of the actuator 31 described above, the same reference numerals are given to the constituent elements having the same function, and the description is repeated. Is omitted. The nut member 39 and the push / pull member 67 are integrally connected via a connecting rod 71.

  With the above configuration, the lever members 59L and 59R and the link members 61L and 61R for rotating the pair of left and right eccentric shafts 57L and 57R in the left and right eccentric shaft units 55L and 55R are toggle mechanisms 73L as an example of a force-increasing mechanism. , 73R. Therefore, when the servo motor 35 in the left and right actuators 69 is driven to rotate the ball screw 37 forward and backward, the nut member 39 is moved up and down. Therefore, the link members 61L and 61R are pushed and pulled through the push / pull member 67.

  As is clear from FIG. 5, when the push-pull member 67 is lowered from the raised position, the lower end sides of the lever members 59L and 59R and the link members 61L and 61R in the left and right toggle mechanisms 73L and 73R are separated from each other. It is rotated as follows. That is, the pair of eccentric shafts 57L and 57R provided in the left and right eccentric shaft units 55R and 55L are rotated in opposite directions. And the eccentric part with which each eccentric shaft 57L and 57R was equipped will be raised gradually from lower side, and will push the lower table 5 upward.

  As described above, when the lower ends of the link members 61L and 61R are turned away from each other, the included angle between the link members 61L and 61R gradually increases. Therefore, the output of the servo motor 35 is transmitted from the ball screw 37 and the nut member 39 to the eccentric shafts 57L and 57R via the toggle mechanisms 73L and 73R. That is, the output of the servo motor 35 is increased and transmitted to the eccentric shafts 57L and 57R. Therefore, the servo motor 35 can be reduced in size and size.

  By the way, in the configuration shown in FIG. 5, the actuating device 69 for actuating the left and right eccentric shaft units 55L and 55R is individually provided. Therefore, the left and right eccentric shaft units 55L and 55R can be individually operated. That is, the left and right crowning in the lower table 5 can be performed individually.

  Therefore, for example, when step bending is performed sequentially on the left side, center portion, and right side of the lower table 5, as in step bending, crowning corresponding to the bending position of the workpiece becomes possible. is there. Accordingly, bending with higher accuracy is possible.

  The present invention is not limited to the embodiment described above, and can be implemented in other forms by making appropriate changes. In other words, as the force-increasing mechanism, instead of the toggle mechanism as described above, an eccentric shaft is provided with, for example, a large-diameter sector gear, and the sector gear is rotated by a small-diameter gear, or the sector gear is configured as a worm gear. It is also possible to use a structure that rotates with a worm.

  Furthermore, the configuration of the boosting mechanism (boost mechanism) may be configured to rotate the eccentric shaft via a lever crank mechanism using a “lever”, for example.

  The place where the actuator is provided is not limited to the rear plate, but may be a front plate. Further, it may be a part of a frame such as the left and right side frames.

  In the above description, the case where the eccentric shaft units 55L and 55R for crowning the lower table are provided on both the left and right sides of the lower table 5 has been described. However, in the case where the press brake is small, it is also possible to adopt a configuration in which an eccentric shaft unit is provided at one position in the center of the lower table 5. Moreover, when the lower table 5 is long in the left-right direction, it is also possible to have a configuration in which eccentric shaft units are provided at the central portion of the lower table 5 and at three locations on the left and right sides. That is, the number of eccentric shaft units can be set to a desired number.

  FIG. 6 shows a configuration of a boosting (boost) mechanism of the third embodiment for rotating the eccentric shaft provided in the eccentric shaft unit. In this embodiment, the same reference numerals are given to components having the same functions as the components in the above-described embodiments, and redundant description is omitted.

  In the third embodiment, eccentric shaft units 55L and 55R are disposed in through holes 17L and 17R formed in the front plate 11, the lower table 5, and the rear plate 13, respectively. The left and right eccentric shafts 57L and 57R (see FIG. 7B) provided in the eccentric shaft units 55L and 55R are lever members 59L that constitute a part of the long toggle mechanisms 73L and 73R that are the force-increasing link mechanisms. , 59R are attached integrally.

  And the front-end | tip part of link member 61L, 61R is pivotally connected via the hinge pin 63 to the front-end | tip part of each lever member 59L, 59R. In the link members 61L and 61R, one link member 61R is configured to be longer than the other link member 61L. The base end portion of the other link member 61L is pivotally connected to an intermediate position of the one link member 61R via a pivot shaft 81.

  In the above configuration, the lever members 59L and 59R and the link members 61L and 61R constitute an intensifying link mechanism (toggle mechanisms 73L and 73R). Then, both ends of a telescopic connecting member 83 for rotating the eccentric shafts 57L and 57R via the force-increasing link mechanism are provided at the distal end portions (free end portions) of the left and right link members 61R in the left and right force-increasing link mechanisms. The parts are pivotally connected via a pivot 85. The connecting member 83 is divided into a first connecting portion 83A having a ball screw 87 rotatably and a second connecting portion 83B having a ball nut 89 screwed to the ball screw 87. The first connecting portion 83A is provided with a servo motor 91 for rotating the ball screw 87.

  Therefore, the entire length of the connecting member 83 can be adjusted by rotating the servo motor 91 and adjusting the screwed state of the ball screw 87 and the ball nut 89. Therefore, the eccentric shafts 57L and 57R in the left and right eccentric shaft units 55L and 55R can be rotated by the servo motor 91. That is, it is possible to adjust the crowning of the lower table 5 by driving the left and right eccentric shaft units 55L and 55R.

  FIG. 8 shows a fourth embodiment for rotating the eccentric shaft provided in the eccentric shaft unit. In this embodiment, the connecting member 83 for operating the left and right eccentric shaft units 55L and 55R via the left and right toggle mechanisms 73L and 73R is divided into three parts.

  That is, the end portions of the first connecting member 83A including the ball screw 87 are pivotally connected to the link member 61R in the toggle mechanisms 73L and 73R. And between the 1st connection part 83A of both sides, the 2nd connection part 83B provided with the ball nut 89 screwed together with the said ball screw 87 at both ends is arrange | positioned.

  With the above configuration, the connecting member 83 can be expanded and contracted by rotationally driving the ball screw 87 by the servo motors 91 provided in the first connecting portions 83A on both sides. Therefore, the eccentric shafts provided in the left and right eccentric shaft units 55L and 55R can be rotated to crown the lower table 5.

  In the above configuration, since the servo motor 91 is provided, the servo motor 91 can be downsized. In addition, as a structure which expands / contracts the connection member 83, it is also possible to use the fluid pressure cylinder which can be expanded / contracted, for example instead of the ball screw mechanism mentioned above.

  FIG. 9 shows a fifth embodiment. In the fifth embodiment, the left and right eccentric shaft units 55L and 55R provided in the left and right through holes 17L and 17R formed in communication with the front plate 11, the lower table 5 and the rear plate 13 are connected to the left and right toggles. It is the structure which act | operates separately by the mechanisms 93L and 93R.

  Since the left and right toggle mechanisms 93L and 93R have the same or bilateral configuration, only one toggle mechanism 93L will be described, and the other toggle mechanism 93R will not be described. In addition, the same reference numerals are given to components having the same functions as the components in the above-described embodiment, and redundant description is omitted.

  Referring to FIG. 10, the eccentric shaft unit 55L operated by the toggle mechanism 93L is provided with left and right eccentric shafts 57L and 57R (see FIG. 11). The eccentric shafts 57L and 57R include lever members 59L and 57L. The base end of 59R is attached. The front ends of the lever members 59L and 59R are pivotally connected to the front ends of the T-shaped link members 95L and 95R via hinge pins 63 (see FIG. 13). The base ends of the link members 95L and 95R are pivotally connected to the push / pull member 67 via the pivot 65.

  The push / pull member 67 is moved up and down by a servo motor 35 attached to the rear plate 13. That is, the servo motor 35 is supported by a support bracket 33 attached to the rear surface of the rear plate 13. A ball screw 37 rotated by a servo motor 35 is supported on the support bracket 33 vertically and rotatably. A nut member 39 integrally connected to the push-pull member 67 is screwed to the ball screw 37 so as to be movable up and down.

  Therefore, the push-pull member 67 is moved up and down via the nut member 39 by rotating the ball screw 37 forward and backward by the servo motor 35. Therefore, the eccentric shafts 57L and 57R in the eccentric shaft unit 55L are rotated via the toggle mechanism 93L including the link members 95L and 95R and the lever members 59L and 59R.

  As already understood, the eccentric shafts 57L and 57R are rotated by the servo motor 35 as an actuator. As described above, the biasing means for assisting the operation of the servo motor 35 is provided when the eccentric shafts 57L and 57R are rotated by the servo motor 35.

  That is, an end plate 99 is provided on the lateral sides of the link members 95L and 95R. The end plate 99 is integrally provided at both ends of a plurality of guide rods 97 that are long in the left-right direction. A left and right L-shaped slide plate 101 having a left and right cross section that is movable toward and away from each other is movably supported at an intermediate position in the left and right direction of the guide rod 97.

  The left and right slide plates 101 are pivotally connected to the distal ends of the arm portions 95LA and 95RA provided in the link members 95L and 95R via the pivot shaft 102. The arm portions 95LA and 95RA are provided so as to protrude in a direction intersecting the longitudinal direction of the link members 95L and 95R. Therefore, the link members 95L and 95R are T-shaped.

  A plurality of coil springs 103 are mounted between the end plate 99 and the slide plate 101. The coil spring 103 constitutes an urging means for assisting the operation of the servo motor 35. That is, the coil spring 103 is compressed and always functions in a direction in which the left and right slide plates 101 approach each other.

  Each of the hinge pins 63 described above is also provided with a seat plate 105 (see FIG. 13). Between the seat plates 105, a plurality of coil springs 107 as urging means are mounted.

  In the above configuration, when the servomotor 35 is operated to move the push-pull member 67 up and down in FIG. 13, the pivot 65 pivotally attached to the left and right link members 95L and 95R is moved up and down. Accordingly, the eccentric shafts 57L and 57R in the eccentric shaft unit 55L are rotated via the link members 95L and 95R and the lever members 59L and 59R.

  As described above, when the eccentric shafts 57L and 57R are rotated through the push-pull member 67, that is, when the push-pull member 67 is lowered and the lower table 5 is crowned in FIG. Assists in a direction in which the left and right slide plates 101 are pressed toward each other. Further, the coil spring 107 assists in a direction in which the left and right hinge pins 63 are separated.

  That is, the coil springs 103 and 107 as urging means assist driving of the servo motor 35 when the lower table 5 is crowned. Therefore, the servo motor 35 can be reduced in size and energy can be saved. In the above configuration, the left and right eccentric shaft units 55L and 55R can be individually operated. Therefore, when step bending of the work is performed by changing the position of the lower table 5 in the left-right direction, the lower table 5 can be crowned corresponding to each bending position.

  FIG. 14 shows a sixth embodiment. This embodiment corresponds to a combination of the above-described embodiment shown in FIGS. 9 to 13 and the embodiment of the connecting member 83 in the embodiment shown in FIG. Therefore, the duplicate description is abbreviate | omitted as attaching | subjecting the same code | symbol to the component which show | plays the same function.

  In the sixth embodiment, the left and right toggle mechanisms 93L and 93R are configured to work together. That is, in the sixth embodiment, the servo motor 35 in the embodiment shown in FIG. 9 is omitted. Then, in the link member 95L in the toggle mechanisms 93L and 93R, as shown in FIG. 15, the arm portion 95LA is formed so as to largely protrude upward from the pivot 102 portion. In the above configuration, the left and right arm portions 95LA are provided with the connecting member 83 according to the embodiment shown in FIG.

  Also in the sixth embodiment, the plurality of coil springs 103 and 107 assist the operation of the servo motor 91, and the same effects as described above can be obtained.

  18 to 21 show a seventh embodiment. In the seventh embodiment, the left and right toggle mechanisms 93L and 93R are provided with coil springs as urging means, and the left and right toggle mechanisms 93L and 93R are interlocked by a single servo motor. .

  More specifically, the toggle mechanisms 93L and 93R have lever members 59L and 59R attached to the eccentric shafts 57L and 57R in the left and right eccentric shaft units 55L and 55R (see FIG. 21), similarly to the configuration described above. . Link members 61L and 61R are pivotally connected to the lever members 59L and 59R via hinge pins 63, respectively. The link members 61L and 61R are pivotally connected via a pivot 65. With the above configuration, toggle mechanisms 93L and 93R are configured by the lever members 59L and 59R and the link members 61L and 61R.

  And in order to link both toggle mechanisms 93L and 93R, the front-end | tip part of each link member 61L in both toggle mechanisms 93L and 93R is pivotally connected by the connection member 83. As shown in FIG. Therefore, both the toggle mechanisms 93L and 93R are operated in conjunction with each other by rotating the ball screw 87 forward and backward by the servo motor 91 provided in the connecting member 83 to expand and contract the connecting member 83. Therefore, the eccentric shafts 57L and 57R in the left and right eccentric shaft units 55L and 55R are simultaneously rotated in conjunction with each other to perform crowning.

  As described above, the biasing means for assisting the rotation of the eccentric shafts 57L and 57R when performing crowning is configured as follows (see FIG. 20).

  In other words, the urging means includes urging means 109A and 109B that assist the link members 61L and 61R individually. That is, the urging means 109 </ b> A includes a seat plate 113 pivotally attached to the rear plate 13 via the pivot 111. In addition, a seat plate 117 pivotally attached to the link member 61L via the pivot 115 is provided. A coil spring 119 is mounted between the seat plates 113 and 117. The coil spring 119 acts and assists so as to press the link member 61L.

  The biasing means 109 </ b> B includes a seat plate 123 pivotally attached to the rear plate 13 via a pivot 121. Further, a bracket 127 pivotally attached to the link member 61R via the pivot 125 is provided. A rod 129 provided integrally with the bracket 127 penetrates the seat plate 123 slidably, and a seat plate 131 is provided at the tip of the rod 129. A coil spring 133 is mounted between the seat plate 123 and the seat plate 131.

  That is, the urging means 109B acts to assist the pulling of the link member 61R.

  As can be understood from the above description, according to the present invention, when the eccentric shaft in the press brake is rotated to perform crowning, the eccentricity is made via a toggle mechanism as an example of a booster mechanism (a booster mechanism). The shaft is rotated. Therefore, the actuator for rotating the eccentric shaft can be downsized.

  Further, an urging means for assisting an operation of a toggle mechanism (intensifying link mechanism) for rotating the eccentric shaft is provided. Therefore, the actuator can be further downsized due to the synergistic effect of the effect of the toggle mechanism and the effect of the urging means.

  By the way, the biasing means is not limited to the coil spring as described above, and a gas spring, for example, can also be used.

DESCRIPTION OF SYMBOLS 1 Press brake 3L, 3R Side frame 5 Lower table 7 Upper table 11 Front plate 13 Rear plate 15L, 15R Axis 17L, 17R Through-hole 19L, 19R Eccentric shaft unit 23 Eccentric shaft 23E Eccentric part 29 Elevating block 29A Press plate 31 Actuator (Actuator)
35 Servo motor 37 Ball screw 39 Nut member 41L, 41R Boosting mechanism (boost mechanism)
43 lever member 45 hinge pin 47 connecting member 49L, 49R link member 51 pivot 53 push-pull member 55L, 55R eccentric shaft unit 57L, 57R eccentric part 59L, 59R lever member 61L, 61R link member 63 hinge pin 65 pivot 67 push-pull member 69 operation Device (actuator)
73L, 73R Toggle mechanism (Intensification mechanism)
83 connecting member 83A first connecting portion 83B second connecting portion 85 pivot 87 ball screw 89 ball nut 91 servo motor 93L, 93R toggle mechanism 95L, 95R T-shaped link member 97 guide rod 99 end plate 101 slide plate 103 coil spring ( Energizing means)
105 Seat plate 107 Coil spring (biasing means)
109A, 109B Energizing means 111 Pivot 113 Seat plate 115 Pivot 117 Seat plate 119 Coil spring 121 Pivot 125 Pivot 127 Bracket 129 Rod 131 Seat plate 133 Coil spring

The present invention has been made in view of the problems as described above, and includes a front plate and a rear plate before and after a lower table attached to the lower side of the left and right side frames in a press brake, and a lower mold provided in the lower table. A crowning method in a press brake comprising an upper table provided with an upper mold for bending a plate-like workpiece in cooperation with the upper side of the left and right side frames, wherein the upper table is freely movable up and down. A force-increasing mechanism comprising a toggle mechanism is provided between an actuator for rotating an eccentric shaft provided in the lower table for crowning the table and the eccentric shaft, and the output of the actuator is supplied to the force-increasing mechanism. Is increased and transmitted to the eccentric shaft, and the eccentric shaft is rotated to perform crowning.

In addition, the front plate and the rear plate are arranged before and after the lower table supported by the left and right side frames in the press brake, and a plurality of eccentric shafts provided in the lower table are rotated apart from each other in the left-right direction. A crowning method of a press brake for performing crowning, comprising a force-increasing mechanism constituted by a toggle mechanism between an actuator for rotating each eccentric shaft and each eccentric shaft, and an output of the actuator is The force is increased by a force-increasing mechanism and transmitted to the eccentric shafts, and the eccentric shafts are rotated to perform crowning.

Also, the front plate and the rear plate are arranged on the front and rear of the lower table supported by the left and right side frames in the press brake, and the eccentric shaft mechanisms provided on the lower table are rotated apart from each other in the left-right direction. A crowning method of a press brake for performing crowning, comprising a force-increasing mechanism constituted by a toggle mechanism between each eccentric shaft mechanism and each actuator for individually rotating each eccentric shaft mechanism, The outputs of the actuators are increased by the force-increasing mechanisms and transmitted to the eccentric shaft mechanisms, and the eccentric shaft mechanisms are individually rotated to perform crowning.

In addition, front plates and rear plates are provided on the front and rear of the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake provided with an upper table having an upper mold to be moved up and down on the upper side of the left and right side frames, and an eccentric shaft for crowning the lower table can be rotated to the lower table. provided, between the actuator and the eccentric shaft for rotating said eccentric shaft, it is transmitted to the Kihen mandrel prior to energizing the output of the actuator, which is provided with a boosting mechanism which is composed of a toggle mechanism It is.

In addition, front plates and rear plates are provided on the front and rear of the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake having an upper table with an upper mold to be moved up and down on the upper side of the left and right side frames, wherein left and right eccentric shafts for crowning the lower table are separated in the left-right direction A toggle mechanism that is provided in the lower table so as to be rotatable, and between an actuator for rotating the eccentric shaft and each of the eccentric shafts, an output of the actuator is increased and transmitted to each of the eccentric shafts. It is equipped with a boosting mechanism.

In addition, front plates and rear plates are provided on the front and rear of the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake having an upper table with an upper mold to be moved up and down on the upper side of the left and right side frames, wherein left and right eccentric shafts for crowning the lower table are separated in the left-right direction The lower table is rotatably provided, and each eccentric shaft is individually operated to increase the output of each actuator between each eccentric shaft and each eccentric shaft. Each of them is provided with a force-increasing mechanism composed of a toggle mechanism that individually transmits them.

In the press brake, the eccentric shaft includes a plurality of eccentric shafts arranged in parallel in the left-right direction, and the toggle mechanism includes each lever member provided integrally with each eccentric shaft provided in parallel. The distal end portion of each link member is pivotally connected to the distal end portion, and the proximal end portion of each link member pivotally connected to each other is pushed and pulled by the actuator.

In addition, front plates and rear plates are provided on the front and rear of the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake having an upper table with an upper mold to be moved up and down on the upper side of the left and right side frames, wherein left and right eccentric shafts for crowning the lower table are separated in the left-right direction The lower table is configured to be rotatable, and includes a toggle mechanism that increases the output of the actuator and transmits it to each eccentric shaft between the eccentric shaft and an actuator for rotating each eccentric shaft. And an urging means for assisting the operation of the actuator when the eccentric shaft is rotated by the actuator.

Claims (21)

  A front plate and a rear plate are provided before and after the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A crowning method in a press brake having an upper table provided with a mold, which is movable up and down on the upper side of the left and right side frames, and an eccentric shaft provided in the lower table for crowning the lower table. A booster mechanism is provided between the actuator for rotating and the eccentric shaft, and the output of the actuator is increased by the booster mechanism and transmitted to the eccentric shaft, and the eccentric shaft is rotated to perform crowning. A method of crowning a press brake, characterized in that   A front plate and a rear plate are arranged on the front and rear of the lower table supported by the left and right side frames in the press brake, and a plurality of eccentric shafts provided on the lower table are spaced apart in the left-right direction to rotate the crown. A press brake crowning method, comprising: an actuator for rotating the eccentric shafts, and an eccentric mechanism between the eccentric shafts; and the output of the actuator is increased by the boost mechanism to A method of crowning a press brake, wherein the crowning is performed by transmitting to an eccentric shaft and rotating each of the eccentric shafts.   3. The press brake crowning method according to claim 2, wherein the force-increasing mechanism extends in a direction intersecting with the axis of each of the left and right eccentric shafts, and is provided integrally with each of the eccentric shafts. The link member having the distal end portion pivotally coupled to the distal end portion of each lever member and the proximal end portion pivotally coupled to each link member are pushed in a direction intersecting the longitudinal direction of each link member. The actuator includes a pulling actuator, and when rotating the eccentric shafts separated from each other in the left and right directions, the eccentric shafts are synchronized and rotated in opposite directions to perform crowning. The press brake crowning method.   A front plate and a rear plate are arranged before and after the lower table supported by the left and right side frames in the press brake, and each eccentric shaft mechanism provided in the lower table is rotated in the left-right direction to rotate the crown. A press brake crowning method, comprising a force-increasing mechanism between each eccentric shaft mechanism and each actuator for individually rotating each eccentric shaft mechanism, and outputting the output of each actuator, A press brake crowning method, wherein the force is increased by each force increasing mechanism and transmitted to each eccentric shaft mechanism, and each eccentric shaft mechanism is individually rotated to perform crowning.   5. The press brake crowning method according to claim 4, wherein each of the eccentric shaft mechanisms spaced apart in the left-right direction includes a pair of left and right eccentric shafts so as to be rotatable. A crowning method for a press brake, characterized in that when the eccentric shafts are rotated, the respective eccentric shafts are synchronized and rotated in opposite directions to perform crowning.   A front plate and a rear plate are provided before and after the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake provided with an upper table having a mold on the upper side of the left and right side frames so as to freely move up and down, and an eccentric shaft that performs crowning of the lower table is rotatably provided on the lower table, A press brake comprising a force-increasing mechanism for increasing the output of the actuator and transmitting it to each eccentric shaft between the actuator for rotating the eccentric shaft and the eccentric shaft.   A front plate and a rear plate are provided before and after the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake provided with an upper table having a mold on the upper side of the left and right side frames so as to be movable up and down, wherein left and right eccentric shafts for crowning the lower table are separated from each other in the left and right direction and the lower part A force-increasing mechanism for increasing the output of the actuator and transmitting it to each eccentric shaft is provided between the actuator for rotating the eccentric shaft and each eccentric shaft. Press brake characterized by.   8. The press brake according to claim 7, wherein the force-increasing mechanism is provided so as to extend in a direction intersecting with the axis of each of the left and right eccentric shafts, and is provided integrally with each of the eccentric shafts. And each link member having a distal end portion pivotally connected to the distal end portion of each lever member, and a proximal end portion pivotally connected to each link member are pushed and pulled by the actuator. Press brake.   The press brake according to claim 7 or 8, wherein each of the left and right eccentric shafts includes a plurality of eccentric shafts arranged in parallel in the left-right direction, and the plurality of eccentric shafts provided in parallel are synchronized with each other. A press brake characterized by being configured to rotate in the same direction.   A front plate and a rear plate are provided before and after the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake provided with an upper table having a mold on the upper side of the left and right side frames so as to freely move up and down, and left and right eccentric shaft mechanisms that perform crowning of the lower table are separated in the left and right direction, and A lower table is rotatably provided, and each eccentric shaft mechanism is individually operated to increase the output of each actuator between each separately provided actuator and each eccentric shaft mechanism. A press brake comprising a force-increasing mechanism for individually transmitting to a shaft mechanism.   The press brake according to any one of claims 6 to 10, wherein the force-increasing mechanism is constituted by a toggle mechanism.   The press brake according to claim 11, wherein the eccentric shaft includes a plurality of eccentric shafts arranged in parallel in the left-right direction, and the toggle mechanism is provided integrally with each eccentric shaft provided in parallel. The distal end portion of each link member is pivotally connected to the distal end portion of each lever member, and the proximal end portion of each link member that is pivotally connected is pushed and pulled by the actuator. Press brake.   12. The press brake according to claim 7, wherein the actuator is a servo motor, and a member that pushes and pulls a pivot connection portion of each link member is a ball screw rotated by the servo motor. A press brake characterized by being a ball nut screwed so as to freely reciprocate.   14. The press brake according to claim 13, wherein the ball screw is disposed in a plane parallel to the plate surface of the lower table, and a rotation axis of the servo motor is in a plane parallel to the plate surface of the lower table. A press brake characterized by being arranged.   A front plate and a rear plate are provided before and after the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake provided with an upper table having a mold on the upper side of the left and right side frames so as to be movable up and down, wherein left and right eccentric shafts for crowning the lower table are separated from each other in the left and right direction and the lower part A table is provided rotatably, and is provided with a free end side of each intensifying link mechanism in which a base end side is connected to the left and right eccentric shafts, and both ends of a connecting member that can be extended and contracted are connected. An actuator for performing an operation is provided in the connecting member.   16. The press brake according to claim 15, wherein the connecting member includes a ball screw mechanism at both ends, and an actuator that individually operates the ball screw mechanisms at both ends.   The press brake according to claim 15 or 16, wherein the force-increasing link mechanism pivots the distal end portion of each link member to the distal end portion of each lever member having a proximal end portion connected to each eccentric shaft provided adjacent thereto. The link member is provided with one link member longer than the other link member, and the base end side of the other link member is pivotally connected to an intermediate position of the one link member. The press brake is characterized in that an end portion of the connecting member is connected to a base end side of the one link member.   A front plate and a rear plate are provided before and after the lower table attached to the lower side of the left and right side frames in the press brake. A press brake having an upper table with a mold on the upper side of the left and right side frames so as to freely move up and down. A table, and a force-increasing mechanism for increasing the output of the actuator and transmitting it to each eccentric shaft between the actuator for rotating each eccentric shaft and the eccentric shaft; and A press brake comprising biasing means for assisting the operation of the actuator when the eccentric shaft is rotated by the actuator.   A front plate and a rear plate are provided before and after the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake provided with an upper table having a mold on the upper side of the left and right side frames so as to be movable up and down, wherein left and right eccentric shafts for crowning the lower table are separated from each other in the left and right direction and the lower part The table is provided rotatably, and is provided with both ends of an extendable connecting member connected to the free end of each intensifying link mechanism in which the base end side is connected to the left and right eccentric shafts. Provided with a ball screw mechanism and an actuator that individually operates the ball screw mechanisms on both ends, and when each of the force-increasing link mechanisms is operated by each of the actuators. , Press brake, characterized in that it comprises a biasing means for assisting the operation of each actuator.   A front plate and a rear plate are provided before and after the lower table attached to the lower side of the left and right side frames in the press brake, and the plate-shaped workpiece is bent in cooperation with the lower mold provided on the lower table. A press brake provided with an upper table having a mold on the upper side of the left and right side frames so as to be movable up and down, wherein left and right eccentric shafts for crowning the lower table are separated from each other in the left and right direction and the lower part The table is rotatably provided, and the both end sides of the extendable connecting member are connected to the free end side of each intensifying link mechanism in which the base end side is connected to the left and right eccentric shafts. An actuator for rotating a ball screw mechanism is provided in the connecting member, and the actuating link mechanism is operated by the actuator via the connecting member when the actuating link mechanism is operated. Press brake, characterized in that the biasing means is provided in each energizing link mechanism to assist the operation of Yueta. 21. The press brake according to claim 18, wherein the urging means is a compression spring.

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