Patent ID: 12240027

DESCRIPTION OF EMBODIMENT

Hereinafter, the present embodiment will be described with reference toFIGS.1to8.

Note that in the description and the claims of the present application, the term “provided” means not only directly provided but also indirectly provided via another member. The term “lateral direction” is one of the horizontal directions, which is a lateral direction of the press brake, and is also referred to as the Y-axis direction. The phrase “inside in the lateral direction” means the center side of the press brake in the lateral direction. The term “front-rear direction” is a horizontal direction orthogonal to the lateral direction, which is a depth direction of the press brake, and is also referred to as the L-axis direction. In the drawings, “FF” indicates the front direction, “FR” indicates the rear direction, “L” indicates the left direction, “R” indicates the right direction, “U” indicates the upward direction, and “D” indicates the downward direction.

As shown inFIG.1, a press brake10according to the present embodiment is a working machine that bends a plate-shaped workpiece (a sheet metal) W by the collaboration between an upper tool (punch tool)12and a lower tool (die tool)14. The press brake10includes with a main frame16, and the main frame16includes a pair of side plates18that are separated and opposed to each other in the lateral direction, and a plurality of connecting members (not shown) that integrally connect the pair of side plates18. The pair of side plates18are first (left side) and second (right side) side plates18.

A lower table20extending in the lateral direction is provided at the lower part of the front surface side (the front side) of the main frame16. A lower tool holder22, which retains the lower tool14so as to be installable and removeable, is provided on the upper side of the lower table20. Further, an upper table24extending in the lateral direction is provided at the upper part of the front surface side of the main frame16so as to be able to ascend and descend (so as to be vertically movable). The upper table24is ascended and descended by the driving of an elevating hydraulic cylinder (not shown) or an elevating motor (not shown) as an elevating actuator for a table provided at an appropriate position on the main frame16. An upper tool holder26, which retains the upper tool12so as to be installable and removable, is provided on the lower side of the upper table24. In lieu of configuring the upper table24so as to be able to ascend and descend, the lower table20may be configured so as to be able to ascend and descend.

A back gauge device28for positioning the workpiece W in the front-rear direction with respect to the lower tool14is provided on the back side (the rear side) of the lower table20in the main frame16. In the schematic partial cross-sectional view ofFIG.1, the back gauge device28provided inside in the lateral direction of the second (right side) side plate18is illustrated on the back side (the rear side) of the lower table20. The specific configuration of the back gauge device28will be described below.

As shown inFIGS.1to6, a pair of support blocks (guide blocks)30, which are separated and opposed to each other in the lateral direction, are provided on the back side of the lower table20in the main frame16. The pair of support blocks30are first (left side) and second (right side) support blocks30. The first support block30is fixed to the first side plate18, and the second support block30is fixed to the second side plate18. Each of the support blocks30has, on the back side thereof, a guide portion30gextending vertically. Each of the support blocks30includes, inside in the lateral direction thereof, a protrusion30pthat protrudes in the rear direction. Further, an elevating member32extending vertically is provided via a slide rail34to the guide portion30gof each of the support blocks30so as to be able to ascend and descend. The pair of elevating members32are first (left side) and second (right side) elevating members32. The first elevating member32includes, on the back side thereof, two protrusions32pand32bthat are vertically separated. The second elevating member32includes, on the lower end side thereof, an extending portion32eextending downward. Note that the drawings of the present application show, as an example, a state in which the pair of elevating members32are positioned at the lowest position.

A ball screw36extending vertically is provided between the two protrusions32pand32bof the first elevating member32so as to be rotatable. An elevating motor38that causes the ball screw36to rotate is provided, via a bracket40, to the protrusion32bof the first elevating member32. An output shaft of the elevating motor38is interlocked and connected to the ball screw36via two pulleys42and44and a timing belt46. The ball screw36is ascended and descended while being rotated by the driving of the elevating motor38. Further, a nut member48screwed into the ball screw36is provided to the protrusion30pof the first support block30. The back gauge device28includes one ball screw mechanism for elevation, which includes the ball screw36and the nut member48. Note that in lieu of providing the ball screw36to the first elevating member32so as to be rotatable, the ball screw36may be provided to the first support block30so as to be rotatable. In this case, the nut member48is provided not to the first support block30but to the first elevating member32.

An electromagnetic brake50that secures the ball screw36in a nonrotatable manner is provided to the protrusion32pof the first elevating member32. The electromagnetic brake50is configured to secure the ball screw36by a braking force in a nonrotatable manner when the power of the press brake10is turned off. Note that the electromagnetic brake50is a body separated from the elevating motor38, but the elevating motor38may include the electromagnetic brake. The back gauge device28may include another brake (not shown) that secures the ball screw36in a nonrotatable manner in lieu of the electromagnetic brake50.

A plurality of tension springs52are provided in parallel between the protrusion30pof the second support block30and the extending portion32eof the second elevating member32, as balancers that reduce gravity acting on the second elevating member32. The plurality of tension springs52are urging members that urge the second elevating member32upward. The upper end portion of each of the tension springs52is locked to the protrusion30pof the second support block30via a bracket54, and the lower end portion of each of the tension springs52is locked to the lower end portion of the extending portion32eof the second elevating member32.

As shown inFIGS.5to8, a square pipe-shaped stretch56extending in the lateral direction is provided between the upper end portion of the first elevating member32and the upper end portion of the second elevating member32. The stretch56includes connecting portions56jand56con one end side and the other end side in the lateral direction thereof, respectively. The connecting portion56jof the stretch56is connected, so as to be rotationally movable (swingable), to the upper end portion of the first elevating member32via a first connecting bolt58as a first connecting pin. The first connecting bolt58is screwed into the upper end portion of the first elevating member32. The connecting portion56cof the stretch56is connected, so as to be rotationally movable, to the upper end portion of the second elevating member32via a second connecting bolt60as a second connecting pin. The second connecting bolt60is screwed into the upper end portion of the second elevating member32.

A support mechanism62that supports the stretch56from below is provided on the upper end side of the first elevating member32. The support mechanism62includes a support base64provided on the upper end side of the first elevating member32and extending inside in the lateral direction. The support mechanism62includes an adjusting screw66that is provided by being screwed into a distal end portion of the support base64and that contacts (supports) the stretch56from below, and upper and lower lock nuts68and70that prevent the adjusting screw66from being loosened. The support mechanism62adjusts levelness of the stretch56when the stretch56moves rotationally around the first connecting bolt58.

As shown inFIGS.3,5, and6, a pair of Y-axis sliders72is provided to the stretch56so as to be movable in the lateral direction via a plurality of guide rails74. Each of the Y-axis sliders72extends in the front-rear direction. A Y-axis motor76, which causes each of the Y-axis sliders72to move in the lateral direction with respect to the stretch56, is provided on the back side of each of the Y-axis sliders72. A rack member78extending in the lateral direction is provided on the back surface of the stretch56. A pinion80is provided to an output shaft of each of the Y-axis motors76, and each of the pinions80is engaged with the rack member78. Note that as an example, the drawings of the present application show a state in which the pair of Y-axis sliders72are most separated in the lateral direction.

An L-axis slider82is provided on the upper surface of each of the Y-axis sliders72so as to be movable in the front-rear direction via a pair of guide rails84. An L-axis motor86, which causes each of the L-axis sliders82to move in the front-rear direction with respect to each of the Y-axis sliders72, is provided at the rear end portion of each of the Y-axis sliders72. A ball screw88extending in the front-rear direction is provided on the upper surface of each of the Y-axis sliders72so as to be rotatable, and each of the ball screws88is interlocked and connected to an output shaft of each of the L-axis motors86via a coupling90. A nut member92is provided to the rear end portion of each of the L-axis sliders82, and each of the nut members92is screwed into each of the ball screws88.

As shown inFIGS.1,5, and6, an abutting base94is provided on the upper surface of each of the L-axis sliders82, and a mounting shaft96is provided to a distal end portion of each of the abutting bases94. An abutting member98, which has a known configuration that is shown in Patent Literature 2, is provided to each of the mounting shafts96. In other words, the pair of abutting members98are provided to the stretch56via the pair of Y-axis sliders72, the pair of L-axis sliders82, and the like. Each of the abutting members98includes, on a distal end side thereof, an abutting surface98fagainst which an end surface Wf of the workpiece W can be abutted. Each of the abutting members98is configured to be movable in the lateral direction and the front-rear direction with respect to the main frame16. Each of the abutting members98moves in the lateral direction integrally with the Y-axis slider72with respect to the main frame16by the driving of the Y-axis motor76. Each of the abutting members98moves in the front-rear direction integrally with the L-axis slider82with respect to the main frame16by the driving of the L-axis motor86. Each of the abutting members98is configured to be able to be installed to and removed from each of the mounting shafts96and to be able to be folded up with an axial center of each of the mounting shafts96as a center.

Subsequently, the operation and effect of the press brake10according to the present embodiment will be described.

(Normal Action of Press Brake10)

The pair of elevating members32are ascended and descended by the driving of the elevating motor38. Thereby, the stretch56is ascended and descended integrally with the pair of elevating members32, which causes the abutting surface98fof each of the abutting members98to be positioned at a height position corresponding to the lower tool14. Further, each of the abutting members98is moved in the lateral direction integrally with each of the Y-axis sliders72by the driving of each of the Y-axis motors76. Thereby, the interval in the lateral direction between the pair of abutting members98is adjusted according to a bending length of the workpiece W. Further, each of the abutting members98is moved in the front-rear direction integrally with each of the L-axis sliders82by the driving of each of the L-axis motors86, which causes the abutting surface98fof each of the abutting members98to be positioned at a predetermined position in the front-rear direction.

After that, the workpiece W is moved in the rear direction and the end surface Wf of the workpiece W is abutted against the abutting surfaces98fof the pair of abutting members98. Thereby the workpiece W is positioned in the front-rear direction with respect to the lower tool14. Then, the upper table24is lowered, which causes the workpiece W to be bent by the collaboration between the upper tool12and the lower tool14. At this time, since each of the abutting members98is folded up with the axial center of each of the mounting shafts96as a center, it is possible to prevent damage to the abutting member98and the like, which is caused by the folding-up of the workpiece W. Note that after the workpiece W is bent, the upper table24is raised to return to the original state.

(Specific Action of Press Brake10)

In the press brake10, as described above, the connecting portion56jof the stretch56is connected, so as to be rotationally movable, to the upper end portion of the first elevating member32via the first connecting bolt58. The connecting portion56cof the stretch56is connected, so as to rotationally movable, to the upper end portion of the second elevating member32via the second connecting bolt60. The second connecting bolt60is screwed into the upper end portion of the second elevating member32. The support mechanism62that supports the stretch56from below is provided on the upper end side of the first elevating member32. The plurality of tension springs52that reduce the gravity acting on the second elevating member32are provided in parallel between the protrusion30pof the second support block30and the extending portion32eof the second elevating member32. Therefore, by providing only one ball screw mechanism for elevation, which includes the ball screw36and the nut member48, to the back gauge device28, the pair of elevating members32can be ascended and descended by the driving of one elevating motor38.

Prior to bending of the workpiece W, the power of the press brake10is turned off and the ball screw36is secured in a nonrotatable manner by the electromagnetic brake50. Then, the stretch56is moved rotationally around the first connecting bolt58so that the stretch56becomes level by a rotary operation of the adjusting screw66in a state in which the gravity acting on the second elevating member32is reduced by the plurality of tension springs52. As a result, the levelness of the stretch56can be easily adjusted.

(Effect of Press Brake10)

According to the present embodiment, as described above, by providing only one ball screw mechanism for elevation to the back gauge device28, the pair of elevating members32can be ascended and descended by the driving of one elevating motor38and the levelness of the stretch56can be easily adjusted. Therefore, according to the present embodiment, it is possible to simplify the adjustment work of the back gauge device28while reducing the cost of the press brake10.

Note that the present invention is not limited to the description of the present embodiment described above, and can be carried out in various other aspects by making appropriate changes, such as configuring each of the support blocks30so as to be movable in the front-rear direction with respect to the main frame16. Then, the scope of rights included in the present invention is not limited to the description of the present embodiment described above.

The entire contents of Japanese Patent Application No. 2020-102874 (application date: Jun. 15, 2020) are incorporated herein.