Die changing device for bending machine, and die changing method for bending machine

Abstract

A tool storage drum (60) includes a plurality of storage slots (63) capable of respectively storing a plurality of center tools (32) having different lengths. A center tool unit (70) includes a center arm (72) to which a center tool (32) is mountable, and configured to be switchable, by pivoting of the center arm (72) about a rotation axis (A1) extending in a left-right direction, to a sprung-up state where the center tool (32) is changeable. A transfer unit (80) includes left and right hands (81L, 81R) arranged side by side in the left-right direction and configured to move in the left-right direction while maintaining a distance between the left hand and the right hand. The transfer unit (80) transfers the center tool (32) between the storage slot and the center arm arranged on an extension line of a movement direction of the left and right hands (81L, 81R). The movement direction of the left and right hands (81L, 81R) corresponds to a direction in which the center tool (32) is inserted / removed into / from the storage slot (63) and the center arm (72).

Description

[TECHNICAL FIELD]

[0001] The present disclosure relates to a tool changer for a bending machine and a tool changing method for a bending machine.[BACKGROUND ART]

[0002] A bending machine is known that comprises a top die including a center tool and a large number of reference tools provided on the left and right sides of the center tool, and a bottom die opposing this top die. The bending machine further comprises a bend-beam provided behind the top die and the bottom die and configured to be swingable in an up-down direction.

[0003] While a workpiece is fixed by the top and bottom dies, the bend-beam is swung upward or downward. An end portion of the workpiece protruding rearward from the top and bottom dies is subjected to bending (ironing and bending) by a bending mold mounted to a front upper or lower part of the bend-beam. In the bending machine, prior to the bending, the size of the center tool (length of the tool in a left-right direction) and the number of left and right reference tools are selected depending on the bending length of the workpiece.

[0004] Patent Literature 1 discloses a tool changer for changing a center tool. This tool changer includes a tool magazine and a center tool unit. The tool magazine includes left and right tool storage drums provided at the front of an upper frame. Each tool storage drum stores a plurality of center tools. The center tool unit is provided movably in the left-right direction and pivotably on a tool supporting beam provided at the lower end of the upper frame.[Citation List][Patent Literature]

[0005] [Patent Literature 1] Japanese Patent Publication No. 3268909[SUMMARY OF INVENTION]

[0006] The tool changer disclosed in Patent Literature 1, however, has a drawback in that time during which processing cannot be performed is prolonged. That is, after a used center tool set in a top die is stored in a tool storage drum, a center tool unit must remain on standby until the tool storage drum rotates, and a desired center tool reaches the center tool unit.

[0007] One aspect of one or more embodiments relates to a tool changer mounted on a bending machine including an upper frame provided with a top die including a center tool and movable in an up-down direction, and a lower frame provided with a bottom die opposing the top die, the bending machine configured to bend a workpiece while the workpiece is fixed between the top die and the bottom die. This tool changer includes a tool storage device including a plurality of storage slots capable of respectively storing a plurality of center tools having different lengths, a center tool unit including a center arm to which a center tool is mountable, and configured to be switchable, by pivoting of the center arm about a rotation axis extending in a left-right direction, between a reference state where the center tool is aligned as part of the top die and a sprung-up state where the center tool is changed, and a transfer unit including left and right hands arranged side by side in the left-right direction to move in the left-right direction while maintaining a distance between the left hand and the right hand, the transfer unit configured to transfer the center tool between a storage slot and the center arm arranged on an extension line in a movement direction of the left and right hands. The movement direction of the left and right hands corresponds to a direction in which the center tool is inserted / removed into / from the storage slot and the center arm.

[0008] According to this tool changer, the storage slot and the center arm are arranged on the extension line of the movement direction of the left and right hands, and the movement direction of the left and right hands corresponds to the direction in which the center tool is inserted / removed into / from the storage slot and the center arm.

[0009] Therefore, a used center tool and a scheduled center tool can be held with the left and right hands, respectively, so that there is no need to wait for the operation of the tool storage device, as is required when switching the center tools with one hand. In addition, by moving the left and right hands in the left-right direction, the used center tool can be removed from the center arm with one hand while the scheduled center tool can be mounted to the center arm with the other hand.

[0010] According to the tool changer related to one or more embodiments, the changing operation of the center tool with respect to the center arm can be performed efficiently. This makes it possible to suppress the prolongation of time during which processing cannot be performed.[BRIEF DESCRIPTION OF DRAWINGS]

[0011] [FIG. 1] FIG. 1 is a diagram showing the main part of a tool changer according to a present embodiment. [FIG. 2] FIG. 2 is a front view showing a bending machine according to the present embodiment. [FIG. 3] FIG. 3 is a side view showing the bending machine according to the present embodiment. [FIG. 4] FIG. 4 is a front view showing the main part of the tool changer according to the present embodiment. [FIG. 5] FIG. 5 is a diagram showing the pivoting operation of the center tool unit provided in the tool changer according to the present embodiment. [FIG. 6] FIG. 6 is a perspective view showing the main part of the tool changer according to the present embodiment. [FIG. 7] FIG. 7 is a side view showing the sprung-up state of the center arm according to the present embodiment. [FIG. 8] FIG. 8 is a diagram showing the main part of the tool changer according to the present embodiment. [FIG. 9] FIG. 9 is a diagram showing the main part of the tool changer according to the present embodiment. [FIG. 10] FIG. 10 is a diagram showing a tool changing method according to a first embodiment. [FIG. 11] FIG. 11 is a diagram showing the tool changing method according to the first embodiment. [FIG. 12] FIG. 12 is a diagram showing a tool changing method according to a second embodiment. [FIG. 13] FIG. 13 is a diagram showing a tool changing method according to a third embodiment. [FIG. 14] FIG. 14 is a diagram showing a tool changing method according to the third embodiment. [DESCRIPTION OF EMBODIMENTS]

[0012] Hereinafter, with reference to the drawings, a tool changer for a bending machine according to a present embodiment and a tool changing method for the bending machine will be described.(First Embodiment)

[0013] First, with reference to FIGS. 1 to 3, an overview of a bending machine 1 according to the first embodiment will be described. FIG. 1 is a diagram showing the main part of a tool changer according to the present embodiment. FIG. 2 is a front view showing the bending machine according to the present embodiment. FIG. 3 is a side view showing the bending machine according to the present embodiment. In describing the configuration of the bending machine 1, as directions, left-right, front-rear, and up-down directions are defined for use. The left-right direction and front-rear direction correspond to two directions that are orthogonal in a horizontal plane, while the up-down direction corresponds to a perpendicular direction. In the drawings, rightward, leftward, upward, downward, forward, and rearward are indicated as RT, LT, UP, DN, FR, and RR, respectively. However, these directions are merely conveniently defined directions for describing a processing machine according to the present embodiment.

[0014] A tool changer 50 according to the present embodiment is mounted on the bending machine 1. The bending machine 1 includes an upper frame 20 provided with a top die 30 including a center tool 32, and movable in the up-down direction, and a lower frame 10 provided with a bottom die 14 opposing the top die 30, and bends a workpiece W while the workpiece W is fixed between the top die 30 and the bottom die 14. The tool changer 50 includes a tool storage drum 60 including a plurality of storage slots 63 capable of respectively storing a plurality of center tools 32 having different lengths, a center tool unit 70 including a center arm 72 to which the center tool 32 is mountable, and configured to be switchable, by pivoting of the center arm 72 about a rotation axis A1 extending in a left-right direction, between a reference state where the center tool 32 is aligned as a part of the top die 30 and a sprung-up state where the center tool is changeable, and a transfer unit 80 including a left hand 81L and a right hand 81R arranged side by side in the left-right direction to move in the left-right direction while maintaining a distance between the left hand and the right hand, and configured to transfer the center tool 32 between the storage slot 63 and the center arm 72 arranged on an extension line of a movement direction of the left hand 81L and the right hand 81R. The movement direction of the left hand 81L and the right hands 81R corresponds to a direction in which the center tool 32 is inserted / removed into / from the storage slot 63 and the center arm 72.

[0015] Next, with reference to FIGS. 2 and 3, the detailed configuration of the bending machine 1 according to the first embodiment will be described. The bending machine 1 according to the present embodiment is a machine that bends the workpiece W into a desired shape by performing bending (ironing and bending) on an edge of the plate-like workpiece W and is also referred to as a panel bender. In front of this bending machine 1, a manipulator (not shown) for supplying and positioning the workpiece W is disposed.

[0016] The bending machine 1 includes the lower frame 10, the upper frame 20, the bottom die 14, the top die 30, a bend-beam 40, the tool changer 50, and a control device 100.

[0017] The lower frame 10 is formed with a laterally elongated shape along the left-right direction and is fixed to the front part of a fixed frame 12. On an upper portion of the lower frame 10, the bottom die 14 serving as a fixed tool is provided to extend in the left-right direction.

[0018] The upper frame 20 is formed with a laterally elongated shape along the left-right direction and is fixed to the front part of a movable frame 22. The movable frame 22 is provided above the fixed frame 12 and is configured to be swingable in the up-down direction with a rotary shaft 24 as a fulcrum. The top die 30 serving as a movable tool opposing the bottom die 14 is provided on a lower portion of the upper frame 20.

[0019] The movable frame 22 is provided with a frame drive mechanism (not shown). When the frame drive mechanism is driven and the movable frame 22 swings upward about the rotary shaft 24, the workpiece W pressed by the bottom die 14 and the top die 30 is released. Conversely, when the movable frame 22 swings downward about the rotary shaft 24, the workpiece W is pressed by the bottom die 14 and the top die 30. This pressing can rigidly fix the workpiece W.

[0020] The top die 30 includes the center tool 32 and a plurality of reference tools 34.

[0021] A tool supporting beam 26 is provided on the lower portion of the upper frame 20. At substantially the center of this tool supporting beam 26 in the left-right direction, the center tool 32 held by the center tool unit 70 is provided, which will be described later. On the left side of the center tool 32 in the tool supporting beam 26, one or more reference tools 34 are provided, and on the right side of the center tool 32 in the tool supporting beam 26, one or more reference tools 34 are provided.

[0022] In this bending machine 1, a plurality of center tools 32 having different sizes (tool lengths in the left-right direction) are prepared. For example, 14 types of center tools 32 are prepared in increments of 7.5 mm from 100 mm to 197.5 mm. The center tool unit 70 holds the center tool 32 of any size selected from the plurality of center tools 32. The remaining center tools 32 are stored in the tool storage drum 60, which will be described later. Note that the illustration of the center tools 32 stored in the tool storage drum 60 is omitted in the drawings. Also, the plurality of center tools 32 are not limited to the aforementioned forms. For example, it is also possible to prepare 20 types of center tools 32 in increments of 5.0 mm from 100 mm to 195 mm.

[0023] On the upper portion of each reference tool 34, a tool selecting cylinder 28 is provided. Furthermore, an opening and closing cylinder 36 is provided in the upper frame 20. By operating the selected tool selecting cylinder 28, it is possible to select a necessary reference tool 34 from the left and right reference tools 34. This allows the reference tools 34 that constitute the top die 30 to be brought closer toward the center tool 32 or separated from the center tool 32.

[0024] The size of the center tool 32 and the number of left and right reference tools 34 are determined depending on the bending length of the workpiece W. Then, the center tool 32 is changed by the tool changer 50.

[0025] The bend-beam 40 is disposed behind the bottom die 14 and the top die 30. The bend-beam 40 extends in the left-right direction. The bend-beam 40 is configured to be movable in the front-rear direction and swingable in the up-down direction about a connecting shaft 42 and is driven by a bend-beam drive mechanism (not shown). The bend-beam 40 is operated to move in the up-down direction and the front-rear direction, causing a front end of the bend-beam 40 to draw an arc. A normal bending tool 44 for performing normal bending is provided in a lower portion of the front end of the bend-beam 40. A reverse bending tool 46 for performing reverse bending is provided in an upper portion of the front end of the bend-beam 40.

[0026] The tool changer 50 is a device that changes the center tool 32 forming a part of the top die 30. Details of the tool changer 50 will be described later.

[0027] The control device 100 includes a computer including a hardware processor such as a central processing unit (CPU), a memory, and various interfaces. The memory and various interfaces are connected to the hardware processor via a bus. By executing programs stored in the memory by the hardware processor, various functions provided by the control device 100 are achieved.

[0028] The control device 100 controls the operation of the bending machine 1. In addition, the control device 100 is also a control device that controls the operation of the tool changer 50.

[0029] In such a bending machine 1, the bending of the workpiece W is performed as follows. That is, the control device 100 drives the frame drive mechanism and lowers the movable frame 22 against the workpiece W positioned by the manipulator. When the movable frame 22 lowers, the workpiece W is pressed by the bottom die 14 and the top die 30, and the workpiece W is fixed. The control device 100 drives the bend-beam drive mechanism and swings the bend-beam upward or downward. When the bend-beam is swung upward, normal bending is performed by the normal bending tool 44, and when the bend-beam is swung downward, reverse bending is performed by the reverse bending tool 46.

[0030] Next, with reference to FIGS. 2 to 7, the tool changer 50, which is one of features of the present embodiment, will be described. FIG. 4 is a front view showing the main part of the tool changer according to the present embodiment. FIG. 5 is a diagram showing a pivoting operation of the center tool unit provided in the tool changer according to the present embodiment. FIG. 6 is a perspective view showing the main part of the tool changer according to the present embodiment. FIG. 7 is a side view showing the sprung-up state of the center arm according to the present embodiment.

[0031] As shown in FIGS. 2 and 3, the tool changer 50 includes the tool storage drum 60, the center tool unit 70, and the transfer unit 80. The center tool 32 is changed by the center tool unit 70 and the transfer unit 80. The changeable center tool 32 is stored in the tool storage drum 60.

[0032] The tool storage drum 60 is attached at the front of the upper frame 20 and is disposed above the center tool unit 70, which will be described later. The tool storage drum 60 is a rotary tool storage device that stores the plurality of center tools 32. The tool storage device applicable to the tool changer 50 may include a configuration other than a rotary configuration, such as a lifting-type configuration for raising and lowering in the up-down direction. The tool storage drum 60 includes a chain 61, a drum drive mechanism 62, and the plurality of storage slots 63.

[0033] The chain 61 runs over a pair of sprockets (not shown). The pair of sprockets is rotatable about a pair of rotary shafts A21 and A22 extending in the left-right direction, and the rotary shafts A21 and A22 of the pair are spaced apart in the up-down direction. The chain 61 is provided with the plurality of storage slots 63 arranged at regular intervals along a running direction of the chain 61. Instead of the chain 61, a belt may be used.

[0034] The drum drive mechanism 62 includes, for example, a drive motor, gears, and others, and rotationally drives one of the sprockets. When the one sprocket is rotationally driven, the chain 61 rotationally runs accordingly.

[0035] As shown in FIG. 6, the plurality of storage slots 63 rotate in accordance with the rotational run of the chain 61. Under the control of the control device 100, the chain 61 rotationally runs, so that any storage slot 63 of the plurality of storage slots 63 is positioned at a drum lowest position. The lowest position of the drum is the lowest position of a rotational trajectory of the storage slot 63, where the center tool 32 can be inserted / removed by the transfer unit 80. In the following description, the rotational run of the chain 61 and the rotation of the plurality of storage slots 63 along the chain 61 may be represented as the rotation of the tool storage drum 60.

[0036] The storage slot 63 stores the center tool 32. The storage slot 63 is composed of a pair of holding members 63a and 63b that hold the center tool 32. The pair of holding members 63a and 63b face each other to sandwich the center tool 32 from opposite sides.

[0037] For example, in the storage slot 63 at the lowest position of the drum, one holding member 63a is located at the front, and the other holding member 63b is located at the rear. The front holding member 63a has a flange shape protruding rearward, while the rear holding member 63b has a flange shape protruding forward. A flange length of the rear holding member 63b in the front-rear direction is set shorter than a flange length of the front holding member 63a in the front-rear direction.

[0038] The front holding member 63a and the rear holding member 63b are arranged with a certain distance apart, creating a space extending in the left-right direction between the pair of holding members 63a and 63b. This space allows the center tool 32 to be inserted / removed into / from the storage slot 63. The direction in which the center tool 32 is inserted / removed into / from the storage slot 63 corresponds to the left-right direction.

[0039] A plunger 63c for positioning and fixing the center tool 32 to be stored is provided at a flange tip of the rear holding member 63b. Another plunger 63c is similarly provided on the front holding member 63a. The plunger 63c may be provided on only one of the front holding member 63a and the rear holding member 63b.

[0040] As shown in FIG. 2, the center tool unit 70 is mounted at the front of the upper frame 20 and is disposed below the tool storage drum 60. The center tool unit 70 is a unit that holds the center tool 32 to align the center tool as a part of the top die 30 and that allows the center tool 32 to be changed.

[0041] As shown in FIG. 4, the center tool unit 70 is mainly composed of a unit base 71, the center arm 72, an arm pivot mechanism 73, and an arm moving mechanism 74.

[0042] The unit base 71 is a member that supports the center arm 72. The upper frame 20 is provided with a guide member (not shown) extending in the left-right direction, and the unit base 71 is configured to be movable in the left-right direction via the guide member.

[0043] The center arm 72 is attached to the unit base 71. The center arm 72 is configured to be rotatable about the rotation axis A1 extending in the left-right direction. The center tool 32 is mounted to the tip of the center arm 72. As shown by a solid line in FIG. 5, the center arm 72 can pivot between a downward state (hereinafter referred to as a "reference state") where the center tool 32 is aligned as a part of the top die 30 and an upward state (hereinafter referred to as a "sprung-up state") where the center tool 32 is located above, as shown by a two dot chain line in FIG. 5. This sprung-up state is a state that allows the center tool 32 to be changed, that is, a state that allows the center tool 32 to be inserted / removed into / from the center arm 72 by the transfer unit 80.

[0044] As shown in FIGS. 5 and 7, the center arm 72 includes an arm body 72a, a holder 72b, and a piston 72c. The center tool 32 mounted to the center arm 72 is composed of a tool body 32a, a holding block 32b that holds the tool body 32a, and a holding piece 32c with a T-shaped cross-section provided at the tip of the holding block 32b.

[0045] The base end of the arm body 72a is rotatably attached to the unit base 71, and the holder 72b for holding the center tool 32 is attached to the tip of the arm body 72a. The holder 72b is provided with a space extending in the left-right direction. This space is formed to be more than one size larger than the holding piece 32c of the center tool 32, and the piston 72c is provided in this space.

[0046] The piston 72c is provided with a slot 72c1 extending in the left-right direction. The slot 72c1 is designed to be slightly larger than the holding piece 32c of the center tool 32, allowing the holding piece 32c of the center tool 32 to be inserted / removed into / from the holder 72b through the slot 72c1. That is, the direction in which the center tool 32 is inserted / removed into / from the center arm 72 corresponds to the left-right direction.

[0047] As shown in FIG. 7, a gap is provided in the up-down direction between the space of the holder 72b and the piston 72c, allowing the piston 72c to move in the up-down direction by an air cylinder built in the arm body 72a. When the piston 72c is pulled downward by the air cylinder, connecting portions of the center arm 72 and the center tool 32 come into close contact with each other. This allows the center tool 32 to be fixed to the center arm 72. When the piston 72c is pushed upward by the air cylinder, a clearance occurs at the connection between the center arm 72 and the center tool 32. This allows the center tool 32 to be inserted / removed into / from the center arm. The air cylinder operates in conjunction with the changing operation of the center tool 32 under the control of the control device 100.

[0048] As shown in FIG. 4, the arm pivot mechanism 73 includes, for example, a drive motor, gears, and others, and rotationally drives the center arm 72. By operating the arm pivot mechanism 73, the center arm 72 can be switched between the reference state and the sprung-up state.

[0049] The arm moving mechanism 74 includes, for example, an air cylinder, and can move the unit base 71, that is, the center arm 72 in the left-right direction. By operating the arm moving mechanism 74, the center arm 72 can be moved and positioned in the left-right direction.

[0050] The center arm 72 is positioned so that the center of the center arm 72 in the left-right direction coincides with a machine center of the bending machine 1 in the left-right direction. Currently, the center tool 32 is positioned at the machine center of the bending machine 1. If necessary, by operating the arm moving mechanism 74, the center arm 72 can be positioned at a position shifted leftward or rightward from the machine center. Thus, the center tool 32 can be positioned at the position shifted leftward or rightward from the machine center.

[0051] As shown in FIG. 2, the transfer unit 80 is attached at the front of the upper frame 20 and disposed below the tool storage drum 60 and above the center tool unit 70. The transfer unit 80 transfers the center tool 32 between the tool storage drum 60 and the center tool unit 70. Specifically, the transfer unit 80 transfers the center tool 32 stored in the storage slot 63 at the lowest position of the drum, to mount the center tool to the center arm 72 at a sprung-up position. Furthermore, the transfer unit 80 transfers the center tool 32 mounted to the center arm 72 at the sprung-up position, to store the center tool in the storage slot 63 at the lowest position of the drum.

[0052] As shown in FIG. 4, the transfer unit 80 is mainly composed of a left hand 81L, a right hand 81R, a guide rail 82, and a hand moving mechanism 83.

[0053] The left hand 81L and the right hand 81R are arranged side by side in the left-right direction with a certain distance apart. The left hand 81L and the right hand 81R hold the center tool 32 from both left and right sides.

[0054] As shown in FIG. 6, the left hand 81L includes a housing 81a and left and right fingers 81b and 81c mounted on the housing 81a. The left and right fingers 81b and 81c are arranged side by side in the left-right direction. The left and right fingers 81b and 81c can move in mutually approaching directions and mutually separating directions by being driven by a finger drive mechanism housed in the housing 81a (not shown). When the left and right fingers 81b and 81c move in the mutually approaching directions, the left and right fingers 81b and 81c can be closed to hold the center tool 32. When the left and right fingers 81b and 81c move in the mutually separating directions, the left and right fingers 81b and 81c can be opened to release the center tool 32. The housing 81a may be the finger drive mechanism itself.

[0055] The left finger 81b is mainly composed of a finger base 81b1 and a finger body 81b2. The finger base 81b1 is a member that couples the finger drive mechanism and the finger body 81b2. The finger base 81b1 of the left finger 81b extends diagonally upward and leftward, that is, in a direction away from the center of the hand. The finger body 81b2 is provided at the tip of the finger base 81b1 and extends forward.

[0056] The right finger 81c is mainly composed of a finger base 81c1 and a finger body 81c2, similarly to the left finger 81b. The finger base 81c1 of the right finger 81c extends diagonally upward and rightward, in a direction away from the center of the hand. The finger body 81c2 is attached to the tip of the finger base 81c1 and extends forward.

[0057] Thus, the left and right finger bodies 81b2 and 81c2 are attached to the housing 81a via the finger base 81b1. The left finger body 81b2 is spaced in an upper left direction relative to the housing 81a, while the right finger body 81c2 is spaced in an upper right direction relative to the housing 81a. That is, the left and right finger bodies 81b2 and 81c2 are arranged at positions away from the housing 81a. Thus, the housing 81a is disposed relatively below the left and right finger bodies 81b2 and 81c2.

[0058] The right hand 81R is composed of the housing 81a and the left and right fingers 81b and 81c mounted on the housing 81a, and its configuration is the same as in the left hand 81L.

[0059] As shown in FIG. 2, the guide rail 82 is attached at the front of the upper frame 20 and extends in the left-right direction. As shown in FIG. 4, the left and right hands 81L and 81R are slidably attached to the guide rail 82 and can move along the guide rail 82. The left and right hands 81L and 81R are attached to the guide rail 82 in an integrated state with each other. Therefore, the left and right hands 81L and 81R move in the left-right direction while maintaining a spacing from each other.

[0060] In addition, the storage slot 63 and center arm 72 are arranged on an extension line of the movement direction of the left and right hands 81L and 81R. In the present embodiment, the storage slot 63 is located to the left of the center arm 72. The left and right hands 81L and 81R can transfer the center tool 32 between the storage slot 63 and the center arm 72.

[0061] The hand moving mechanism 83 is composed of, for example, an electric actuator, and moves the left and right hands 81L and 81R in the left-right direction. The hand moving mechanism 83 can move the left and right hands 81L and 81R in the left-right direction and position the hands at predetermined positions under the control of the control device 100.

[0062] Next, with reference to FIGS. 1, 8, and 9, a relative relation between the tool storage drum 60, the center tool unit 70, and the transfer unit 80 will be described. FIGS. 8 and 9 are diagrams showing the main part of the tool changer according to the present embodiment. FIGS. 1, 8, and 9 show the storage slot 63 at the lowest position of the drum, the center arm 72 in the sprung-up state, and the left and right hands 81L and 81R. The center arm 72 of the center tool unit 70 is positioned so that the center of the center arm 72 in the left-right direction coincides with the center of the bending machine 1 in the left-right direction (machine center).

[0063] As shown in FIG. 1, the spacing between the left hand 81L and the right hands 81R is set to distance Da. As described above, since the left and right hands 81L and 81R move in the left-right direction while maintaining the spacing between the hands, the spacing between the left hand 81L and the right hand 81R remains at distance Da regardless of their positions in the left-right direction.

[0064] The tool storage drum 60 is disposed at a position offset to the left of the center tool unit 70, and the storage slot 63 is also disposed at a position offset to the left of the center arm 72. A spacing between the machine center of the storage slot 63 and the machine center of the center arm 72 is set to distance Db.

[0065] These distances Da and Db are set to the same value. Based on such distances Da and Db, four positions are set for the left and right hands 81L and 81R to operate. The four positions include a storage position Pc1, a change position Pc2, a left standby position Pc3, and a right standby position Pc4.

[0066] As shown in FIGS. 1 and 8, the storage position Pc1 is where the left and right hands 81L and 81R are below the storage slot 63, and their respective machine centers coincide. As shown in FIGS. 8 and 9, the change position Pc2 is where the left and right hands 81L and 81R are above the center arm 72, and their respective machine centers coincide. The change position Pc2 is also a position that is a distance Dm to the right of the storage position Pc1.

[0067] The left standby position Pc3 is a position that is a distance Dm to the left of the storage position Pc1. The right standby position Pc4 is a position that is a distance Dm to the right of the change position Pc2.

[0068] The distance Dm described above is the same as the distances Da and Db. Therefore, the left and right hands 81L and 81R are at two adjacent positions of the four positions Pc1 to Pc4 described above.

[0069] That is, as shown in FIG. 1, when the left hand 81L is at the left standby position Pc3, the right hand 81R is at the storage position Pc1. As shown in FIG. 8, when the left hand 81L is at the storage position Pc1, the right hand 81R is at the change position Pc2. As shown in FIG. 9, when the left hand 81L is at the change position Pc2, the right hand 81R is at the right standby position Pc4.

[0070] Based on such relations, the control device 100 controls the hand moving mechanism 83 to position the left and right hands 81L and 81R at the four positions Pc1 to Pc4 described above, or to move them by distance Dm along the left-right direction. As a result, the control device 100 controls the left and right hands 81L and 81R to transition between three states.

[0071] As shown in FIG. 1, a first state is a state where one hand 81R (81L) of the left and right hands 81L and 81R is at a position corresponding to the storage slot 63 (storage position Pc1). In the mechanical configuration of the present embodiment, the above state corresponds to a state where the right hand 81R is at the storage position Pc1, and in this state, the left hand 81L is at the left standby position Pc3.

[0072] As shown in FIG. 8, a second state is a state where one hand 81R (81L) is at a position corresponding to the center arm 72 (change position Pc2), and the other hand 81L (81R) is at a position corresponding to the storage slot 63 (storage position Pc1). In the mechanical configuration of the present embodiment, the above state corresponds to a state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1.

[0073] As shown in FIG. 9, a third state is a state where only one hand 81L (81R) of the left and right hands 81L and 81R is at a position corresponding to the center arm 72 (change position Pc2). In the mechanical configuration of the present embodiment, the above state corresponds to a state where the left hand 81L is at the change position Pc2, and in this state, the right hand 81R is at the right standby position Pc4.

[0074] Next, with reference to FIGS. 10 and 11, a tool changing method using the tool changer 50 will be described. FIGS. 10 and 11 are diagrams showing the tool changing method according to the first embodiment. This tool changing method is executed under the control of the control device 100.

[0075] In the following description, the center tool 32 to be newly mounted at the center arm 72 is referred to as "scheduled center tool 32A", and the center tool 32 already mounted to the center arm 72 is referred to as "used center tool 32B".

[0076] As shown in FIG. 10, the state where the left hand 81L is at the left standby position Pc3 and the right hand 81R is at the storage position Pc1 is defined as an initial state of the left and right hands 81L and 81R (S10). Currently, the left and right hands 81L and 81R are in an open state. Also, at the lowest position of the drum, an empty storage slot 63 is disposed in which the center tool 32 is not stored.

[0077] In step S11, the control device 100 moves the left and right hands 81L and 81R to the right and positions the left hand 81L and the right hand 81R at the storage position Pc1 and the change position Pc2, respectively. Then, the control device 100 rotates the tool storage drum 60 to position, at the lowest position of the drum, the storage slot 63 in which the scheduled center tool 32A is stored. The control device 100 closes the left hand 81L and holds the scheduled center tool 32A with the left hand 81L.

[0078] In step S12, the control device 100 causes the center arm 72 to which the used center tool 32B is mounted, to pivot into the sprung-up state. After the center arm 72 pivots, the control device 100 closes the right hand 81R and holds the used center tool 32B with the right hand 81R. The control device 100 pulls the piston 72c (see FIG. 7) upward to release the fixation of the used center tool 32B to the center arm 72.

[0079] In step S13, the control device 100 moves the left and right hands 81L and 81R to the right. Currently, the scheduled center tool 32A is pulled out from the storage slot 63, and the used center tool 32B is pulled out from the center arm 72. The control device 100 positions the left hand 81L and the right hand 81R at the change position Pc2 and the right standby position Pc4, respectively. During the process of positioning the left hand 81L at the change position Pc2, the scheduled center tool 32A is inserted into the center arm 72. The control device 100 pulls the piston 72c (see FIG. 7) downward to fix the scheduled center tool 32A to the center arm 72.

[0080] In step S14 of FIG. 11, the control device 100 opens the left hand 81L and hands over the scheduled center tool 32A of the left hand 81L to the center arm 72. Once the scheduled center tool 32A is handed over, the control device 100 causes the center arm 72 to which the scheduled center tool 32A is mounted, to pivot into the reference state.

[0081] In step S15, the control device 100 moves the left and right hands 81L and 81R to the left and positions the left hand 81L and the right hand 81R at the left standby position Pc3 and the storage position Pc1, respectively. During the process of positioning the right hand 81R at the storage position Pc1, the used center tool 32B is inserted into the storage slot 63.

[0082] In step S16, the control device 100 opens the right hand 81R and hands over the used center tool 32B to the storage slot 63. Once the used center tool 32B is handed over, the control device 100 rotates the tool storage drum 60 to place, at the lowest position of the drum, an empty storage slot 63 in which the center tool 32 is not stored.

[0083] In step S17, the control device 100 moves the left and right hands 81L and 81R to the right and positions the left hand 81L and the right hand 81R at the storage position Pc1 and the change position Pc2, respectively. Then, when performing a new tool changing operation, the operations of and after step S11 described above are repeated.

[0084] In the series of operations described above, the processes of steps S10 to S11 and S15 to S17 are conducted during the processing operation of the bending machine 1. And the process of steps S12 to S14 is conducted during the non-processing operation of the bending machine 1.

[0085] Thus, according to the tool changer 50 of the present embodiment, the storage slot 63 and the center arm 72 are arranged on the extension line of the movement direction of the left and right hands 81L and 81R, and the movement direction of the left and right hands 81L and 81R corresponds to a direction in which the center tool 32 is inserted / removed into / from the storage slot 63 and the center arm 72.

[0086] Therefore, the used center tool 32B and the scheduled center tool 32A can be held with the left hand 81L and the right hand 81R, respectively, so that there is no need to wait for the rotation of the tool storage drum 60, as is required when switching the center tool 32 with one hand. In addition, by moving the left and right hands 81L, 81R in the left-right direction, the used center tool 32B can be removed from the center arm 72 with one hand 81R (81L) while the scheduled center tool 32A can be mounted to the center arm 72 with the other hand 81L (81R).

[0087] Therefore, according to the tool changer 50 of the present embodiment, the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently. This makes it possible to suppress the prolongation of time during which processing cannot be performed.

[0088] In the present embodiment, the distance Db in the left-right direction between the storage slot 63 and the center arm 72 is the same as the distance Da in the left-right direction between the left hand 81L and the right hand 81R.

[0089] According to this configuration, when the other hand 81L (81R) is at the storage position Pc1, one hand 81R (81L) is at the change position Pc2. Consequently, by moving the left and right hands 81L, 81R by a certain distance in the left-right direction, the used center tool 32B can be removed from the center arm 72 with one hand 81R (81L) while the scheduled center tool 32A can be removed from the storage slot 63 with the other hand 81L (81R). In addition, directly to the center arm 72 from which the used center tool 32B is removed with one hand 81R (81L), the scheduled center tool 32A removed from the storage slot 63 can be mounted with the other hand 81L (81R). Thus, since the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently, it is possible to suppress the prolongation of time during which processing cannot be performed.

[0090] In the present embodiment, the left and right hands 81L and 81R are configured, respectively, to be movable in mutually approaching directions and mutually separating directions, and each hand includes left and right fingers 81b and 81c configured to hold the center tool 32 from both left and right sides, and the housing 81a on which the left and right fingers 81b and 81c are mounted. Each of the left and right fingers includes finger base 81b1, 81c1 extending diagonally upward away from the center of the hand, and the finger body 81b2, 81c2 extending forward from the finger base 81b1, 81c1 to hold the center tool 32.

[0091] According to this configuration, the housing 81a is disposed at the position relatively lower than the left and right finger bodies 81b2, 81c2. This allows for the suppression of situations where the center tool 32 stored in the storage slot 63 interferes with the housing 81a when the tool storage drum 60 is rotated.

[0092] In the present embodiment, the tool changer 50 further includes the control device configured to control the left and right hands.

[0093] According to this configuration, the control device 100 can control the left and right hands 81L and 81R to appropriately change the center tool 32.

[0094] In the present embodiment, the control device 100 controls the movement and positioning of the left and right hands 81L and 81R in the left-right direction to transition between three states. The three states include a state where one of the left and right hands 81L and 81R is at the storage position corresponding to the storage slot, the state where one hand 81R (81L) is at the change position Pc2 corresponding to the center arm 72, and the other hand 81L (81R) of the left and right hands 81L, 81R is at the storage position Pc1, and the state where the other hand 81L (81R) is at the change position Pc2.

[0095] According to this configuration, by transitioning the state of the left and right hands 81L and 81R just once, it is possible to remove the used center tool 32B from the center arm 72 with one hand 81R (81L) while mounting the scheduled center tool 32A to the center arm 72 with the other hand 81L (81R). Thus, since the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently, it is possible to suppress the prolongation of time during which processing cannot be performed.

[0096] In the present embodiment, the tool storage drum 60 is disposed at the position shifted to the left of the center tool unit 70. The control device 100 performs the following steps (1a) to (8a). (1a) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R from the state where the right hand 81R is at the storage position Pc1 to the state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1. (2a) Closing the left hand 81L, thereby holding, with the left hand 81L, the scheduled center tool 32A stored in the storage slot 63. (3a) Closing the right hand 81R, thereby holding, with the right hand 81R, the used center tool 32B mounted to the center arm 72 in the sprung-up state. (4a) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R to the state where the left hand 81L is at the change position Pc2. (5a) Opening the left hand 81L to hand over the scheduled center tool 32A to the center arm 72. (6a) Moving the left and right hands 81L and 81R to the left, thereby transitioning the left and right hands 81L and 81R to the state where the right hand 81R is at the storage position Pc1. (7a) Opening the right hand 81R to hand over the used center tool 32B to the storage slot 63. (8a) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R to the state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1.

[0097] According to this configuration, the left hand 81L manages the scheduled center tool 32A, and the right hand 81R manages the used center tool 32B. Consequently, during the movement of the left and right hands 81L and 81R to the right, it is possible to remove the used center tool 32B from the center arm 72 with the right hand 81R while mounting the scheduled center tool 32A to the center arm 72 with the left hand 81L. Thus, since the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently, it is possible to suppress the prolongation of time during which processing cannot be performed.(Second Embodiment)

[0098] Hereinafter, a tool changer 50 for a bending machine 1 according to a second embodiment and a tool changing method for the bending machine will be described. The configuration of the bending machine 1 and the tool changer 50 according to the second embodiment is the same as that of the first embodiment, but the flow of the tool changing method differs. Hereinafter, the differences from the first embodiment will be mainly described.

[0099] FIG. 12 is a diagram showing the tool changing method according to the second embodiment. In the tool changing method according to the second embodiment, since a process from step S10 to step S14 is the same as in the first embodiment, the description will start from a process of step S15a following step S14.

[0100] In step S15a, a control device 100 moves left and right hands 81L and 81R to the left and positions the left hand 81L and the right hand 81R at a storage position Pc1 and a change position Pc2, respectively.

[0101] In step S16a, the control device 100 rotates a tool storage drum 60 to position, at the lowest position of the drum, a storage slot 63 in which a new scheduled center tool 32C is stored. The control device 100 closes the left hand 81L and holds the new scheduled center tool 32C with the left hand 81L.

[0102] In step S17a, the control device 100 moves the left and right hands 81L and 81R to the left and positions the left hand 81L and the right hand 81R at a left standby position Pc3 and the storage position Pc1, respectively. During a process of positioning the left and right hands 81L and 81R, the new scheduled center tool 32C is pulled out from the storage slot 63, and a used center tool 32B is inserted into the storage slot 63.

[0103] In step S18a, the control device 100 opens the right hand 81R to hand over the used center tool 32B to the storage slot 63. Once the used center tool 32B is handed over, the control device 100 operates the tool storage drum 60 to place, at the lowest position of the drum, an empty storage slot 63 in which any center tool 32 is not stored.

[0104] In step S19a, the control device 100 moves the left and right hands 81L and 81R to the right and positions the left hand 81L and the right hand 81R at the storage position Pc1 and the change position Pc2, respectively. During a process of positioning the left hand 81L at the storage position Pc1, the new scheduled center tool 32C is temporarily inserted into the storage slot 63. Then, to perform a tool changing operation for the new scheduled center tool 32C, an operation of and after step S12 shown in the first embodiment is conducted.

[0105] In the present embodiment, the tool storage drum 60 is disposed at a position shifted to the left of a center tool unit 70. The control device 100 performs the following steps (1b) to (10b). (1b) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R from a state where the right hand 81R is at the storage position Pc1 to a state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1. (2b) Closing the left hand 81L, thereby holding, with the left hand 81L, a scheduled center tool 32A stored in the storage slot 63. (3b) Closing the right hand 81R, thereby holding, with the right hand 81R, the used center tool 32B mounted to a center arm 72 in a sprung-up state. (4b) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R to a state where the left hand 81L is at the change position Pc2. (5b) Opening the left hand 81L to hand over the scheduled center tool 32A to the center arm 72. (6b) Moving the left and right hands 81L and 81R to the left, thereby transitioning the left and right hands 81L and 81R to a state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1. (7b) Closing the left hand 81L, thereby holding, with the left hand 81L, a new scheduled center tool 32C in the storage slot 63. (8b) Moving the left and right hands 81L and 81R to the left, thereby transitioning the left and right hands 81L and 81R to a state where the right hand 81R is at the storage position Pc1. (9b) Opening the right hand 81R to hand over the used center tool 32B to the storage slot 63. (10b) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R to a state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1.

[0106] According to this configuration, the left hand 81L manages the scheduled center tool 32A and the right hand 81R manages the used center tool 32B in the same manner as in the first embodiment. Consequently, during the movement of the left and right hands 81L and 81R to the right, it is possible to remove the used center tool 32B from the center arm 72 with the right hand 81R while mounting the scheduled center tool 32A to the center arm 72 with the left hand 81L. Thus, since the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently, it is possible to suppress the prolongation of time during which processing cannot be performed.

[0107] In addition, the new scheduled center tool 32C can be held with the left hand 81L before the used center tool 32B is stored in the storage slot 63 with the right hand 81R. Consequently, the left hand 81L can smoothly receive the new scheduled center tool 32C.(Third Embodiment)

[0108] Hereinafter, a tool changer 50 for a bending machine 1 according to a third embodiment and a tool changing method for the bending machine will be described. The configuration of the bending machine 1 and the tool changer 50 according to the third embodiment is the same as that of the first embodiment, but the flow of the tool changing method differs. Specifically, in the first embodiment, the scheduled center tool 32A is managed by the left hand 81L, whereas in the third embodiment, a scheduled center tool 32A is managed by a right hand 81R. Hereinafter, the differences from the first embodiment will be mainly described.

[0109] With reference FIGS. 13 and 14, the tool changing method by the tool changer 50 will be described. FIGS. 13 and 14 are diagrams showing the tool changing method according to the third embodiment. This tool changing method is executed under the control of the control device 100.

[0110] As shown in FIG. 13, a state where the left hand 81L is at a left standby position Pc3 and the right hand 81R is at a change position Pc2 is defined as an initial state of the left and right hands 81L and 81R (S20). Currently, the left and right hands 81L and 81R are in an open state. Also, at a drum lowest position, an empty storage slot 63 is disposed in which any center tool 32 is not stored.

[0111] In step S21, the control device 100 rotates a tool storage drum 60 to position the storage slot 63 storing the scheduled center tool 32A at the lowest position of the drum. The control device 100 closes the right hand 81R and holds the scheduled center tool 32A with the right hand 81R.

[0112] In step S22, the control device 100 moves the left and right hands 81L and 81R to the right to position the left hand 81L and the right hand 81R at the change position Pc2 and a right standby position Pc4, respectively.

[0113] In step S23, the control device 100 causes a center arm 72 to which a used center tool 32B is mounted, to pivot into a sprung-up state. After the center arm 72 pivots, the control device 100 closes the left hand 81L and holds the used center tool 32B with the left hand 81L. The control device 100 pulls a piston 72c (see FIG. 7) upward to release the fixation of the used center tool 32B to the center arm 72.

[0114] In step S24 of FIG. 14, the control device 100 moves each of the left and right hands 81L and 81R to the left. At this time, the used center tool 32B is pulled out from the center arm 72. The control device 100 positions the left hand 81L and the right hand 81R to a storage position Pc1 and the change position Pc2, respectively. During a process of positioning the left hand 81L and the right hand 81R to the storage position Pc1 and the change position Pc2, respectively, the scheduled center tool 32A is inserted into the center arm 72, and the used center tool 32B is inserted into the storage slot 63. The control device 100 pulls the piston 72c (see FIG. 7) downward to fix the scheduled center tool 32A to the center arm 72.

[0115] In step S25, the control device 100 opens the right hand 81R to hand over the scheduled center tool 32A to the center arm 72. Once the scheduled center tool 32A is handed over, the control device 100 causes the center arm 72 to which the scheduled center tool 32A is mounted, to pivot into a reference state.

[0116] In step S26, the control device 100 opens the left hand 81L to hand over the used center tool 32B to the storage slot 63. Once the used center tool 32B is handed over, the control device 100 operates the tool storage drum 60 to place, at the lowest position of the drum, an empty storage slot 63 in which any center tool 32 is not stored. The processing in step S26 may be performed simultaneously with the processing in step S25.

[0117] In step S27, the control device 100 moves the left and right hands 81L and 81R to the left and positions the left hand 81L and the right hand 81R at the left standby position Pc3 and the storage position Pc1, respectively. Then, when performing a new tool changing operation, the operations of and after step S21 described above are repeated.

[0118] In the series of operations mentioned above, the processes of steps S20 to S22 and S26 to S27 are performed during a processing operation of the bending machine 1. In addition, the process of steps S23 to S25 is performed during a non-processing operation of the bending machine 1.

[0119] Thus, in the present embodiment, the tool storage drum 60 is disposed at a position shifted to the left of the center tool unit 70. The control device 100 performs each of processes (1c) to (7c) below. (1c) Closing the right hand 81R in a state where the right hand 81R is at the storage position Pc1, thereby holding, with the right hand 81R, the scheduled center tool 32A in the storage slot 63. (2c) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R to a state where the left hand 81L is at the change position Pc2. (3c) Closing the left hand 81L, thereby holding, with the left hand 81L, the used center tool 32B mounted to the center arm 72 in a sprung-up state. (4c) Moving the left and right hands 81L and 81R to the left, thereby transitioning the left and right hands 81L and 81R to a state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1. (5c) Opening the right hand 81R to hand over the scheduled center tool 32A to the center arm 72. (6c) Open the left hand 81L to hand over the used center tool 32B to the storage slot 63. (7c) Move the left and right hands 81L and 81R to the left, thereby transitioning the left and right hands 81L and 81R to a state where the right hand 81R is at the storage position Pc1.

[0120] According to this configuration, the right hand 81R can manage the scheduled center tool 32A, while the left hand 81L can manage the used center tool 32B. Consequently, there is no need to wait for the rotation of the tool storage drum 60, as is required when switching the center tool 32 with one hand. Additionally, during the movement of the left and right hands 81L and 81R to the left, the used center tool 32B can be removed from the center arm 72 with the left hand 81L, while the scheduled center tool 32A can be mounted on the center arm 72 with the right hand 81R. Thus, since the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently, it is possible to suppress the prolongation of time during which processing cannot be performed.

[0121] As above, the tool changer 50 for the bending machine 1 according to the first to third embodiments has been described. Furthermore, the tool changing method for the bending machine 1 also functions as part of the present embodiment. That is, the tool changer 50 for the bending machine 1 includes the tool storage drum 60 including the plurality of storage slots 63 capable of respectively storing the plurality of center tools 32 having different lengths, the center tool unit 70 including the center arm 72 to which the center tool 32 is mountable, and configured to be switchable, by pivoting of the center arm 72 about the rotation axis A1 extending in the left-right direction, between the reference state where the center tool 32 is aligned as a part of the top die 30 and the sprung-up state where the center tool 32 is changeable, and the transfer unit including the left hand 81L and the right hand 81R arranged side by side in the left-right direction to move in the left-right direction while maintaining the distance between the left hand and the right hand, and configured to transfer the center tool between the storage slot and the center arm arranged on the extension line of the movement direction of the left and right hands 81L and 81R. This tool changing method involves changing the center tool between the storage slot 63 and the center arm 72, while transitioning the left and right hands 81L, 81R to three states including the state where one hand 81R (81L) of the left and right hands 81L and 81R is at the storage position Pc1 corresponding to the storage slot 63, the state where the one hand 81R (81L) is at the change position Pc2 corresponding to the center arm 72, and the other hand 81L (81R) of the left and right hands 81L, 81R is at the storage position Pc1, and the state where the other hand 81L (81R) is at the change position Pc2.

[0122] According to the tool changing method of the present embodiment, the storage slot 63 and the center arm 72 are arranged on the extension line of the movement direction of the left and right hands 81L and 81R. Consequently, the left and right hands 81L and 81R can each hold the used center tool 32B and the scheduled center tool 32A, respectively, so there is no need to wait for the rotation of the tool storage drum 60.

[0123] In addition, only by transitioning the state of the left and right hands 81L and 81R once, the used center tool 32B can be removed from the center arm 72 with one hand 81R (81L) while mounting the scheduled center tool 32A to the center arm 72 with the other hand 81L (81R).

[0124] Therefore, according to the tool changing method of the present embodiment, the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently. Consequently, it is possible to suppress the prolongation of time during which processing cannot be performed.

[0125] In each of the embodiments described above, the tool storage drum 60 is disposed at the position shifted to the left of the center tool unit 70. However, the tool storage drum 60 may be disposed at a position shifted to the right of the center tool unit 70. In this case, in the tool changing method, the movements of the left and right hands 81L and 81R described in the first to third embodiments can be interchanged.

[0126] As above, the present embodiment has been described, and it should not be understood that the discussions and drawings that form part of the embodiment limit the embodiment. This embodiment will reveal various alternative forms of implementation, examples, and operational techniques to those skilled in the art.

[0127] The disclosure of this application relates to the subject matter described in Japanese Patent Application No. 2023-097656, filed with the Japan Patent Office on June 14, 2023, and all its disclosures are incorporated herein by reference.

Examples

first embodiment

(First Embodiment)

[0013]First, with reference to FIGS. 1 to 3, an overview of a bending machine 1 according to the first embodiment will be described. FIG. 1 is a diagram showing the main part of a tool changer according to the present embodiment. FIG. 2 is a front view showing the bending machine according to the present embodiment. FIG. 3 is a side view showing the bending machine according to the present embodiment. In describing the configuration of the bending machine 1, as directions, left-right, front-rear, and up-down directions are defined for use. The left-right direction and front-rear direction correspond to two directions that are orthogonal in a horizontal plane, while the up-down direction corresponds to a perpendicular direction. In the drawings, rightward, leftward, upward, downward, forward, and rearward are indicated as RT, LT, UP, DN, FR, and RR, respectively. However, these directions are merely conveniently defined directions for describing a processing machine...

second embodiment

(Second Embodiment)

[0098]Hereinafter, a tool changer 50 for a bending machine 1 according to a second embodiment and a tool changing method for the bending machine will be described. The configuration of the bending machine 1 and the tool changer 50 according to the second embodiment is the same as that of the first embodiment, but the flow of the tool changing method differs. Hereinafter, the differences from the first embodiment will be mainly described.

[0099]FIG. 12 is a diagram showing the tool changing method according to the second embodiment. In the tool changing method according to the second embodiment, since a process from step S10 to step S14 is the same as in the first embodiment, the description will start from a process of step S15a following step S14.

[0100]In step S15a, a control device 100 moves left and right hands 81L and 81R to the left and positions the left hand 81L and the right hand 81R at a storage position Pc1 and a change position Pc2, respectively.

[0101]In...

third embodiment

(Third Embodiment)

[0108]Hereinafter, a tool changer 50 for a bending machine 1 according to a third embodiment and a tool changing method for the bending machine will be described. The configuration of the bending machine 1 and the tool changer 50 according to the third embodiment is the same as that of the first embodiment, but the flow of the tool changing method differs. Specifically, in the first embodiment, the scheduled center tool 32A is managed by the left hand 81L, whereas in the third embodiment, a scheduled center tool 32A is managed by a right hand 81R. Hereinafter, the differences from the first embodiment will be mainly described.

[0109]With reference FIGS. 13 and 14, the tool changing method by the tool changer 50 will be described. FIGS. 13 and 14 are diagrams showing the tool changing method according to the third embodiment. This tool changing method is executed under the control of the control device 100.

[0110]As shown in FIG. 13, a state where the left hand 81L is...

[TECHNICAL FIELD]

[0001] The present disclosure relates to a tool changer for a bending machine and a tool changing method for a bending machine.[BACKGROUND ART]

[0002] A bending machine is known that comprises a top die including a center tool and a large number of reference tools provided on the left and right sides of the center tool, and a bottom die opposing this top die. The bending machine further comprises a bend-beam provided behind the top die and the bottom die and configured to be swingable in an up-down direction.

[0003] While a workpiece is fixed by the top and bottom dies, the bend-beam is swung upward or downward. An end portion of the workpiece protruding rearward from the top and bottom dies is subjected to bending (ironing and bending) by a bending mold mounted to a front upper or lower part of the bend-beam. In the bending machine, prior to the bending, the size of the center tool (length of the tool in a left-right direction) and the number of left and right reference tools are selected depending on the bending length of the workpiece.

[0004] Patent Literature 1 discloses a tool changer for changing a center tool. This tool changer includes a tool magazine and a center tool unit. The tool magazine includes left and right tool storage drums provided at the front of an upper frame. Each tool storage drum stores a plurality of center tools. The center tool unit is provided movably in the left-right direction and pivotably on a tool supporting beam provided at the lower end of the upper frame.[Citation List][Patent Literature]

[0005] [Patent Literature 1] Japanese Patent Publication No. 3268909[SUMMARY OF INVENTION]

[0006] The tool changer disclosed in Patent Literature 1, however, has a drawback in that time during which processing cannot be performed is prolonged. That is, after a used center tool set in a top die is stored in a tool storage drum, a center tool unit must remain on standby until the tool storage drum rotates, and a desired center tool reaches the center tool unit.

[0007] One aspect of one or more embodiments relates to a tool changer mounted on a bending machine including an upper frame provided with a top die including a center tool and movable in an up-down direction, and a lower frame provided with a bottom die opposing the top die, the bending machine configured to bend a workpiece while the workpiece is fixed between the top die and the bottom die. This tool changer includes a tool storage device including a plurality of storage slots capable of respectively storing a plurality of center tools having different lengths, a center tool unit including a center arm to which a center tool is mountable, and configured to be switchable, by pivoting of the center arm about a rotation axis extending in a left-right direction, between a reference state where the center tool is aligned as part of the top die and a sprung-up state where the center tool is changed, and a transfer unit including left and right hands arranged side by side in the left-right direction to move in the left-right direction while maintaining a distance between the left hand and the right hand, the transfer unit configured to transfer the center tool between a storage slot and the center arm arranged on an extension line in a movement direction of the left and right hands. The movement direction of the left and right hands corresponds to a direction in which the center tool is inserted / removed into / from the storage slot and the center arm.

[0008] According to this tool changer, the storage slot and the center arm are arranged on the extension line of the movement direction of the left and right hands, and the movement direction of the left and right hands corresponds to the direction in which the center tool is inserted / removed into / from the storage slot and the center arm.

[0009] Therefore, a used center tool and a scheduled center tool can be held with the left and right hands, respectively, so that there is no need to wait for the operation of the tool storage device, as is required when switching the center tools with one hand. In addition, by moving the left and right hands in the left-right direction, the used center tool can be removed from the center arm with one hand while the scheduled center tool can be mounted to the center arm with the other hand.

[0010] According to the tool changer related to one or more embodiments, the changing operation of the center tool with respect to the center arm can be performed efficiently. This makes it possible to suppress the prolongation of time during which processing cannot be performed.[BRIEF DESCRIPTION OF DRAWINGS]

[0011] [FIG. 1] FIG. 1 is a diagram showing the main part of a tool changer according to a present embodiment. [FIG. 2] FIG. 2 is a front view showing a bending machine according to the present embodiment. [FIG. 3] FIG. 3 is a side view showing the bending machine according to the present embodiment. [FIG. 4] FIG. 4 is a front view showing the main part of the tool changer according to the present embodiment. [FIG. 5] FIG. 5 is a diagram showing the pivoting operation of the center tool unit provided in the tool changer according to the present embodiment. [FIG. 6] FIG. 6 is a perspective view showing the main part of the tool changer according to the present embodiment. [FIG. 7] FIG. 7 is a side view showing the sprung-up state of the center arm according to the present embodiment. [FIG. 8] FIG. 8 is a diagram showing the main part of the tool changer according to the present embodiment. [FIG. 9] FIG. 9 is a diagram showing the main part of the tool changer according to the present embodiment. [FIG. 10] FIG. 10 is a diagram showing a tool changing method according to a first embodiment. [FIG. 11] FIG. 11 is a diagram showing the tool changing method according to the first embodiment. [FIG. 12] FIG. 12 is a diagram showing a tool changing method according to a second embodiment. [FIG. 13] FIG. 13 is a diagram showing a tool changing method according to a third embodiment. [FIG. 14] FIG. 14 is a diagram showing a tool changing method according to the third embodiment. [DESCRIPTION OF EMBODIMENTS]

[0012] Hereinafter, with reference to the drawings, a tool changer for a bending machine according to a present embodiment and a tool changing method for the bending machine will be described.(First Embodiment)

[0013] First, with reference to FIGS. 1 to 3, an overview of a bending machine 1 according to the first embodiment will be described. FIG. 1 is a diagram showing the main part of a tool changer according to the present embodiment. FIG. 2 is a front view showing the bending machine according to the present embodiment. FIG. 3 is a side view showing the bending machine according to the present embodiment. In describing the configuration of the bending machine 1, as directions, left-right, front-rear, and up-down directions are defined for use. The left-right direction and front-rear direction correspond to two directions that are orthogonal in a horizontal plane, while the up-down direction corresponds to a perpendicular direction. In the drawings, rightward, leftward, upward, downward, forward, and rearward are indicated as RT, LT, UP, DN, FR, and RR, respectively. However, these directions are merely conveniently defined directions for describing a processing machine according to the present embodiment.

[0014] A tool changer 50 according to the present embodiment is mounted on the bending machine 1. The bending machine 1 includes an upper frame 20 provided with a top die 30 including a center tool 32, and movable in the up-down direction, and a lower frame 10 provided with a bottom die 14 opposing the top die 30, and bends a workpiece W while the workpiece W is fixed between the top die 30 and the bottom die 14. The tool changer 50 includes a tool storage drum 60 including a plurality of storage slots 63 capable of respectively storing a plurality of center tools 32 having different lengths, a center tool unit 70 including a center arm 72 to which the center tool 32 is mountable, and configured to be switchable, by pivoting of the center arm 72 about a rotation axis A1 extending in a left-right direction, between a reference state where the center tool 32 is aligned as a part of the top die 30 and a sprung-up state where the center tool is changeable, and a transfer unit 80 including a left hand 81L and a right hand 81R arranged side by side in the left-right direction to move in the left-right direction while maintaining a distance between the left hand and the right hand, and configured to transfer the center tool 32 between the storage slot 63 and the center arm 72 arranged on an extension line of a movement direction of the left hand 81L and the right hand 81R. The movement direction of the left hand 81L and the right hands 81R corresponds to a direction in which the center tool 32 is inserted / removed into / from the storage slot 63 and the center arm 72.

[0015] Next, with reference to FIGS. 2 and 3, the detailed configuration of the bending machine 1 according to the first embodiment will be described. The bending machine 1 according to the present embodiment is a machine that bends the workpiece W into a desired shape by performing bending (ironing and bending) on an edge of the plate-like workpiece W and is also referred to as a panel bender. In front of this bending machine 1, a manipulator (not shown) for supplying and positioning the workpiece W is disposed.

[0016] The bending machine 1 includes the lower frame 10, the upper frame 20, the bottom die 14, the top die 30, a bend-beam 40, the tool changer 50, and a control device 100.

[0017] The lower frame 10 is formed with a laterally elongated shape along the left-right direction and is fixed to the front part of a fixed frame 12. On an upper portion of the lower frame 10, the bottom die 14 serving as a fixed tool is provided to extend in the left-right direction.

[0018] The upper frame 20 is formed with a laterally elongated shape along the left-right direction and is fixed to the front part of a movable frame 22. The movable frame 22 is provided above the fixed frame 12 and is configured to be swingable in the up-down direction with a rotary shaft 24 as a fulcrum. The top die 30 serving as a movable tool opposing the bottom die 14 is provided on a lower portion of the upper frame 20.

[0019] The movable frame 22 is provided with a frame drive mechanism (not shown). When the frame drive mechanism is driven and the movable frame 22 swings upward about the rotary shaft 24, the workpiece W pressed by the bottom die 14 and the top die 30 is released. Conversely, when the movable frame 22 swings downward about the rotary shaft 24, the workpiece W is pressed by the bottom die 14 and the top die 30. This pressing can rigidly fix the workpiece W.

[0020] The top die 30 includes the center tool 32 and a plurality of reference tools 34.

[0021] A tool supporting beam 26 is provided on the lower portion of the upper frame 20. At substantially the center of this tool supporting beam 26 in the left-right direction, the center tool 32 held by the center tool unit 70 is provided, which will be described later. On the left side of the center tool 32 in the tool supporting beam 26, one or more reference tools 34 are provided, and on the right side of the center tool 32 in the tool supporting beam 26, one or more reference tools 34 are provided.

[0022] In this bending machine 1, a plurality of center tools 32 having different sizes (tool lengths in the left-right direction) are prepared. For example, 14 types of center tools 32 are prepared in increments of 7.5 mm from 100 mm to 197.5 mm. The center tool unit 70 holds the center tool 32 of any size selected from the plurality of center tools 32. The remaining center tools 32 are stored in the tool storage drum 60, which will be described later. Note that the illustration of the center tools 32 stored in the tool storage drum 60 is omitted in the drawings. Also, the plurality of center tools 32 are not limited to the aforementioned forms. For example, it is also possible to prepare 20 types of center tools 32 in increments of 5.0 mm from 100 mm to 195 mm.

[0023] On the upper portion of each reference tool 34, a tool selecting cylinder 28 is provided. Furthermore, an opening and closing cylinder 36 is provided in the upper frame 20. By operating the selected tool selecting cylinder 28, it is possible to select a necessary reference tool 34 from the left and right reference tools 34. This allows the reference tools 34 that constitute the top die 30 to be brought closer toward the center tool 32 or separated from the center tool 32.

[0024] The size of the center tool 32 and the number of left and right reference tools 34 are determined depending on the bending length of the workpiece W. Then, the center tool 32 is changed by the tool changer 50.

[0025] The bend-beam 40 is disposed behind the bottom die 14 and the top die 30. The bend-beam 40 extends in the left-right direction. The bend-beam 40 is configured to be movable in the front-rear direction and swingable in the up-down direction about a connecting shaft 42 and is driven by a bend-beam drive mechanism (not shown). The bend-beam 40 is operated to move in the up-down direction and the front-rear direction, causing a front end of the bend-beam 40 to draw an arc. A normal bending tool 44 for performing normal bending is provided in a lower portion of the front end of the bend-beam 40. A reverse bending tool 46 for performing reverse bending is provided in an upper portion of the front end of the bend-beam 40.

[0026] The tool changer 50 is a device that changes the center tool 32 forming a part of the top die 30. Details of the tool changer 50 will be described later.

[0027] The control device 100 includes a computer including a hardware processor such as a central processing unit (CPU), a memory, and various interfaces. The memory and various interfaces are connected to the hardware processor via a bus. By executing programs stored in the memory by the hardware processor, various functions provided by the control device 100 are achieved.

[0028] The control device 100 controls the operation of the bending machine 1. In addition, the control device 100 is also a control device that controls the operation of the tool changer 50.

[0029] In such a bending machine 1, the bending of the workpiece W is performed as follows. That is, the control device 100 drives the frame drive mechanism and lowers the movable frame 22 against the workpiece W positioned by the manipulator. When the movable frame 22 lowers, the workpiece W is pressed by the bottom die 14 and the top die 30, and the workpiece W is fixed. The control device 100 drives the bend-beam drive mechanism and swings the bend-beam upward or downward. When the bend-beam is swung upward, normal bending is performed by the normal bending tool 44, and when the bend-beam is swung downward, reverse bending is performed by the reverse bending tool 46.

[0030] Next, with reference to FIGS. 2 to 7, the tool changer 50, which is one of features of the present embodiment, will be described. FIG. 4 is a front view showing the main part of the tool changer according to the present embodiment. FIG. 5 is a diagram showing a pivoting operation of the center tool unit provided in the tool changer according to the present embodiment. FIG. 6 is a perspective view showing the main part of the tool changer according to the present embodiment. FIG. 7 is a side view showing the sprung-up state of the center arm according to the present embodiment.

[0031] As shown in FIGS. 2 and 3, the tool changer 50 includes the tool storage drum 60, the center tool unit 70, and the transfer unit 80. The center tool 32 is changed by the center tool unit 70 and the transfer unit 80. The changeable center tool 32 is stored in the tool storage drum 60.

[0032] The tool storage drum 60 is attached at the front of the upper frame 20 and is disposed above the center tool unit 70, which will be described later. The tool storage drum 60 is a rotary tool storage device that stores the plurality of center tools 32. The tool storage device applicable to the tool changer 50 may include a configuration other than a rotary configuration, such as a lifting-type configuration for raising and lowering in the up-down direction. The tool storage drum 60 includes a chain 61, a drum drive mechanism 62, and the plurality of storage slots 63.

[0033] The chain 61 runs over a pair of sprockets (not shown). The pair of sprockets is rotatable about a pair of rotary shafts A21 and A22 extending in the left-right direction, and the rotary shafts A21 and A22 of the pair are spaced apart in the up-down direction. The chain 61 is provided with the plurality of storage slots 63 arranged at regular intervals along a running direction of the chain 61. Instead of the chain 61, a belt may be used.

[0034] The drum drive mechanism 62 includes, for example, a drive motor, gears, and others, and rotationally drives one of the sprockets. When the one sprocket is rotationally driven, the chain 61 rotationally runs accordingly.

[0035] As shown in FIG. 6, the plurality of storage slots 63 rotate in accordance with the rotational run of the chain 61. Under the control of the control device 100, the chain 61 rotationally runs, so that any storage slot 63 of the plurality of storage slots 63 is positioned at a drum lowest position. The lowest position of the drum is the lowest position of a rotational trajectory of the storage slot 63, where the center tool 32 can be inserted / removed by the transfer unit 80. In the following description, the rotational run of the chain 61 and the rotation of the plurality of storage slots 63 along the chain 61 may be represented as the rotation of the tool storage drum 60.

[0036] The storage slot 63 stores the center tool 32. The storage slot 63 is composed of a pair of holding members 63a and 63b that hold the center tool 32. The pair of holding members 63a and 63b face each other to sandwich the center tool 32 from opposite sides.

[0037] For example, in the storage slot 63 at the lowest position of the drum, one holding member 63a is located at the front, and the other holding member 63b is located at the rear. The front holding member 63a has a flange shape protruding rearward, while the rear holding member 63b has a flange shape protruding forward. A flange length of the rear holding member 63b in the front-rear direction is set shorter than a flange length of the front holding member 63a in the front-rear direction.

[0038] The front holding member 63a and the rear holding member 63b are arranged with a certain distance apart, creating a space extending in the left-right direction between the pair of holding members 63a and 63b. This space allows the center tool 32 to be inserted / removed into / from the storage slot 63. The direction in which the center tool 32 is inserted / removed into / from the storage slot 63 corresponds to the left-right direction.

[0039] A plunger 63c for positioning and fixing the center tool 32 to be stored is provided at a flange tip of the rear holding member 63b. Another plunger 63c is similarly provided on the front holding member 63a. The plunger 63c may be provided on only one of the front holding member 63a and the rear holding member 63b.

[0040] As shown in FIG. 2, the center tool unit 70 is mounted at the front of the upper frame 20 and is disposed below the tool storage drum 60. The center tool unit 70 is a unit that holds the center tool 32 to align the center tool as a part of the top die 30 and that allows the center tool 32 to be changed.

[0041] As shown in FIG. 4, the center tool unit 70 is mainly composed of a unit base 71, the center arm 72, an arm pivot mechanism 73, and an arm moving mechanism 74.

[0042] The unit base 71 is a member that supports the center arm 72. The upper frame 20 is provided with a guide member (not shown) extending in the left-right direction, and the unit base 71 is configured to be movable in the left-right direction via the guide member.

[0043] The center arm 72 is attached to the unit base 71. The center arm 72 is configured to be rotatable about the rotation axis A1 extending in the left-right direction. The center tool 32 is mounted to the tip of the center arm 72. As shown by a solid line in FIG. 5, the center arm 72 can pivot between a downward state (hereinafter referred to as a "reference state") where the center tool 32 is aligned as a part of the top die 30 and an upward state (hereinafter referred to as a "sprung-up state") where the center tool 32 is located above, as shown by a two dot chain line in FIG. 5. This sprung-up state is a state that allows the center tool 32 to be changed, that is, a state that allows the center tool 32 to be inserted / removed into / from the center arm 72 by the transfer unit 80.

[0044] As shown in FIGS. 5 and 7, the center arm 72 includes an arm body 72a, a holder 72b, and a piston 72c. The center tool 32 mounted to the center arm 72 is composed of a tool body 32a, a holding block 32b that holds the tool body 32a, and a holding piece 32c with a T-shaped cross-section provided at the tip of the holding block 32b.

[0045] The base end of the arm body 72a is rotatably attached to the unit base 71, and the holder 72b for holding the center tool 32 is attached to the tip of the arm body 72a. The holder 72b is provided with a space extending in the left-right direction. This space is formed to be more than one size larger than the holding piece 32c of the center tool 32, and the piston 72c is provided in this space.

[0046] The piston 72c is provided with a slot 72c1 extending in the left-right direction. The slot 72c1 is designed to be slightly larger than the holding piece 32c of the center tool 32, allowing the holding piece 32c of the center tool 32 to be inserted / removed into / from the holder 72b through the slot 72c1. That is, the direction in which the center tool 32 is inserted / removed into / from the center arm 72 corresponds to the left-right direction.

[0047] As shown in FIG. 7, a gap is provided in the up-down direction between the space of the holder 72b and the piston 72c, allowing the piston 72c to move in the up-down direction by an air cylinder built in the arm body 72a. When the piston 72c is pulled downward by the air cylinder, connecting portions of the center arm 72 and the center tool 32 come into close contact with each other. This allows the center tool 32 to be fixed to the center arm 72. When the piston 72c is pushed upward by the air cylinder, a clearance occurs at the connection between the center arm 72 and the center tool 32. This allows the center tool 32 to be inserted / removed into / from the center arm. The air cylinder operates in conjunction with the changing operation of the center tool 32 under the control of the control device 100.

[0048] As shown in FIG. 4, the arm pivot mechanism 73 includes, for example, a drive motor, gears, and others, and rotationally drives the center arm 72. By operating the arm pivot mechanism 73, the center arm 72 can be switched between the reference state and the sprung-up state.

[0049] The arm moving mechanism 74 includes, for example, an air cylinder, and can move the unit base 71, that is, the center arm 72 in the left-right direction. By operating the arm moving mechanism 74, the center arm 72 can be moved and positioned in the left-right direction.

[0050] The center arm 72 is positioned so that the center of the center arm 72 in the left-right direction coincides with a machine center of the bending machine 1 in the left-right direction. Currently, the center tool 32 is positioned at the machine center of the bending machine 1. If necessary, by operating the arm moving mechanism 74, the center arm 72 can be positioned at a position shifted leftward or rightward from the machine center. Thus, the center tool 32 can be positioned at the position shifted leftward or rightward from the machine center.

[0051] As shown in FIG. 2, the transfer unit 80 is attached at the front of the upper frame 20 and disposed below the tool storage drum 60 and above the center tool unit 70. The transfer unit 80 transfers the center tool 32 between the tool storage drum 60 and the center tool unit 70. Specifically, the transfer unit 80 transfers the center tool 32 stored in the storage slot 63 at the lowest position of the drum, to mount the center tool to the center arm 72 at a sprung-up position. Furthermore, the transfer unit 80 transfers the center tool 32 mounted to the center arm 72 at the sprung-up position, to store the center tool in the storage slot 63 at the lowest position of the drum.

[0052] As shown in FIG. 4, the transfer unit 80 is mainly composed of a left hand 81L, a right hand 81R, a guide rail 82, and a hand moving mechanism 83.

[0053] The left hand 81L and the right hand 81R are arranged side by side in the left-right direction with a certain distance apart. The left hand 81L and the right hand 81R hold the center tool 32 from both left and right sides.

[0054] As shown in FIG. 6, the left hand 81L includes a housing 81a and left and right fingers 81b and 81c mounted on the housing 81a. The left and right fingers 81b and 81c are arranged side by side in the left-right direction. The left and right fingers 81b and 81c can move in mutually approaching directions and mutually separating directions by being driven by a finger drive mechanism housed in the housing 81a (not shown). When the left and right fingers 81b and 81c move in the mutually approaching directions, the left and right fingers 81b and 81c can be closed to hold the center tool 32. When the left and right fingers 81b and 81c move in the mutually separating directions, the left and right fingers 81b and 81c can be opened to release the center tool 32. The housing 81a may be the finger drive mechanism itself.

[0055] The left finger 81b is mainly composed of a finger base 81b1 and a finger body 81b2. The finger base 81b1 is a member that couples the finger drive mechanism and the finger body 81b2. The finger base 81b1 of the left finger 81b extends diagonally upward and leftward, that is, in a direction away from the center of the hand. The finger body 81b2 is provided at the tip of the finger base 81b1 and extends forward.

[0056] The right finger 81c is mainly composed of a finger base 81c1 and a finger body 81c2, similarly to the left finger 81b. The finger base 81c1 of the right finger 81c extends diagonally upward and rightward, in a direction away from the center of the hand. The finger body 81c2 is attached to the tip of the finger base 81c1 and extends forward.

[0057] Thus, the left and right finger bodies 81b2 and 81c2 are attached to the housing 81a via the finger base 81b1. The left finger body 81b2 is spaced in an upper left direction relative to the housing 81a, while the right finger body 81c2 is spaced in an upper right direction relative to the housing 81a. That is, the left and right finger bodies 81b2 and 81c2 are arranged at positions away from the housing 81a. Thus, the housing 81a is disposed relatively below the left and right finger bodies 81b2 and 81c2.

[0058] The right hand 81R is composed of the housing 81a and the left and right fingers 81b and 81c mounted on the housing 81a, and its configuration is the same as in the left hand 81L.

[0059] As shown in FIG. 2, the guide rail 82 is attached at the front of the upper frame 20 and extends in the left-right direction. As shown in FIG. 4, the left and right hands 81L and 81R are slidably attached to the guide rail 82 and can move along the guide rail 82. The left and right hands 81L and 81R are attached to the guide rail 82 in an integrated state with each other. Therefore, the left and right hands 81L and 81R move in the left-right direction while maintaining a spacing from each other.

[0060] In addition, the storage slot 63 and center arm 72 are arranged on an extension line of the movement direction of the left and right hands 81L and 81R. In the present embodiment, the storage slot 63 is located to the left of the center arm 72. The left and right hands 81L and 81R can transfer the center tool 32 between the storage slot 63 and the center arm 72.

[0061] The hand moving mechanism 83 is composed of, for example, an electric actuator, and moves the left and right hands 81L and 81R in the left-right direction. The hand moving mechanism 83 can move the left and right hands 81L and 81R in the left-right direction and position the hands at predetermined positions under the control of the control device 100.

[0062] Next, with reference to FIGS. 1, 8, and 9, a relative relation between the tool storage drum 60, the center tool unit 70, and the transfer unit 80 will be described. FIGS. 8 and 9 are diagrams showing the main part of the tool changer according to the present embodiment. FIGS. 1, 8, and 9 show the storage slot 63 at the lowest position of the drum, the center arm 72 in the sprung-up state, and the left and right hands 81L and 81R. The center arm 72 of the center tool unit 70 is positioned so that the center of the center arm 72 in the left-right direction coincides with the center of the bending machine 1 in the left-right direction (machine center).

[0063] As shown in FIG. 1, the spacing between the left hand 81L and the right hands 81R is set to distance Da. As described above, since the left and right hands 81L and 81R move in the left-right direction while maintaining the spacing between the hands, the spacing between the left hand 81L and the right hand 81R remains at distance Da regardless of their positions in the left-right direction.

[0064] The tool storage drum 60 is disposed at a position offset to the left of the center tool unit 70, and the storage slot 63 is also disposed at a position offset to the left of the center arm 72. A spacing between the machine center of the storage slot 63 and the machine center of the center arm 72 is set to distance Db.

[0065] These distances Da and Db are set to the same value. Based on such distances Da and Db, four positions are set for the left and right hands 81L and 81R to operate. The four positions include a storage position Pc1, a change position Pc2, a left standby position Pc3, and a right standby position Pc4.

[0066] As shown in FIGS. 1 and 8, the storage position Pc1 is where the left and right hands 81L and 81R are below the storage slot 63, and their respective machine centers coincide. As shown in FIGS. 8 and 9, the change position Pc2 is where the left and right hands 81L and 81R are above the center arm 72, and their respective machine centers coincide. The change position Pc2 is also a position that is a distance Dm to the right of the storage position Pc1.

[0067] The left standby position Pc3 is a position that is a distance Dm to the left of the storage position Pc1. The right standby position Pc4 is a position that is a distance Dm to the right of the change position Pc2.

[0068] The distance Dm described above is the same as the distances Da and Db. Therefore, the left and right hands 81L and 81R are at two adjacent positions of the four positions Pc1 to Pc4 described above.

[0069] That is, as shown in FIG. 1, when the left hand 81L is at the left standby position Pc3, the right hand 81R is at the storage position Pc1. As shown in FIG. 8, when the left hand 81L is at the storage position Pc1, the right hand 81R is at the change position Pc2. As shown in FIG. 9, when the left hand 81L is at the change position Pc2, the right hand 81R is at the right standby position Pc4.

[0070] Based on such relations, the control device 100 controls the hand moving mechanism 83 to position the left and right hands 81L and 81R at the four positions Pc1 to Pc4 described above, or to move them by distance Dm along the left-right direction. As a result, the control device 100 controls the left and right hands 81L and 81R to transition between three states.

[0071] As shown in FIG. 1, a first state is a state where one hand 81R (81L) of the left and right hands 81L and 81R is at a position corresponding to the storage slot 63 (storage position Pc1). In the mechanical configuration of the present embodiment, the above state corresponds to a state where the right hand 81R is at the storage position Pc1, and in this state, the left hand 81L is at the left standby position Pc3.

[0072] As shown in FIG. 8, a second state is a state where one hand 81R (81L) is at a position corresponding to the center arm 72 (change position Pc2), and the other hand 81L (81R) is at a position corresponding to the storage slot 63 (storage position Pc1). In the mechanical configuration of the present embodiment, the above state corresponds to a state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1.

[0073] As shown in FIG. 9, a third state is a state where only one hand 81L (81R) of the left and right hands 81L and 81R is at a position corresponding to the center arm 72 (change position Pc2). In the mechanical configuration of the present embodiment, the above state corresponds to a state where the left hand 81L is at the change position Pc2, and in this state, the right hand 81R is at the right standby position Pc4.

[0074] Next, with reference to FIGS. 10 and 11, a tool changing method using the tool changer 50 will be described. FIGS. 10 and 11 are diagrams showing the tool changing method according to the first embodiment. This tool changing method is executed under the control of the control device 100.

[0075] In the following description, the center tool 32 to be newly mounted at the center arm 72 is referred to as "scheduled center tool 32A", and the center tool 32 already mounted to the center arm 72 is referred to as "used center tool 32B".

[0076] As shown in FIG. 10, the state where the left hand 81L is at the left standby position Pc3 and the right hand 81R is at the storage position Pc1 is defined as an initial state of the left and right hands 81L and 81R (S10). Currently, the left and right hands 81L and 81R are in an open state. Also, at the lowest position of the drum, an empty storage slot 63 is disposed in which the center tool 32 is not stored.

[0077] In step S11, the control device 100 moves the left and right hands 81L and 81R to the right and positions the left hand 81L and the right hand 81R at the storage position Pc1 and the change position Pc2, respectively. Then, the control device 100 rotates the tool storage drum 60 to position, at the lowest position of the drum, the storage slot 63 in which the scheduled center tool 32A is stored. The control device 100 closes the left hand 81L and holds the scheduled center tool 32A with the left hand 81L.

[0078] In step S12, the control device 100 causes the center arm 72 to which the used center tool 32B is mounted, to pivot into the sprung-up state. After the center arm 72 pivots, the control device 100 closes the right hand 81R and holds the used center tool 32B with the right hand 81R. The control device 100 pulls the piston 72c (see FIG. 7) upward to release the fixation of the used center tool 32B to the center arm 72.

[0079] In step S13, the control device 100 moves the left and right hands 81L and 81R to the right. Currently, the scheduled center tool 32A is pulled out from the storage slot 63, and the used center tool 32B is pulled out from the center arm 72. The control device 100 positions the left hand 81L and the right hand 81R at the change position Pc2 and the right standby position Pc4, respectively. During the process of positioning the left hand 81L at the change position Pc2, the scheduled center tool 32A is inserted into the center arm 72. The control device 100 pulls the piston 72c (see FIG. 7) downward to fix the scheduled center tool 32A to the center arm 72.

[0080] In step S14 of FIG. 11, the control device 100 opens the left hand 81L and hands over the scheduled center tool 32A of the left hand 81L to the center arm 72. Once the scheduled center tool 32A is handed over, the control device 100 causes the center arm 72 to which the scheduled center tool 32A is mounted, to pivot into the reference state.

[0081] In step S15, the control device 100 moves the left and right hands 81L and 81R to the left and positions the left hand 81L and the right hand 81R at the left standby position Pc3 and the storage position Pc1, respectively. During the process of positioning the right hand 81R at the storage position Pc1, the used center tool 32B is inserted into the storage slot 63.

[0082] In step S16, the control device 100 opens the right hand 81R and hands over the used center tool 32B to the storage slot 63. Once the used center tool 32B is handed over, the control device 100 rotates the tool storage drum 60 to place, at the lowest position of the drum, an empty storage slot 63 in which the center tool 32 is not stored.

[0083] In step S17, the control device 100 moves the left and right hands 81L and 81R to the right and positions the left hand 81L and the right hand 81R at the storage position Pc1 and the change position Pc2, respectively. Then, when performing a new tool changing operation, the operations of and after step S11 described above are repeated.

[0084] In the series of operations described above, the processes of steps S10 to S11 and S15 to S17 are conducted during the processing operation of the bending machine 1. And the process of steps S12 to S14 is conducted during the non-processing operation of the bending machine 1.

[0085] Thus, according to the tool changer 50 of the present embodiment, the storage slot 63 and the center arm 72 are arranged on the extension line of the movement direction of the left and right hands 81L and 81R, and the movement direction of the left and right hands 81L and 81R corresponds to a direction in which the center tool 32 is inserted / removed into / from the storage slot 63 and the center arm 72.

[0086] Therefore, the used center tool 32B and the scheduled center tool 32A can be held with the left hand 81L and the right hand 81R, respectively, so that there is no need to wait for the rotation of the tool storage drum 60, as is required when switching the center tool 32 with one hand. In addition, by moving the left and right hands 81L, 81R in the left-right direction, the used center tool 32B can be removed from the center arm 72 with one hand 81R (81L) while the scheduled center tool 32A can be mounted to the center arm 72 with the other hand 81L (81R).

[0087] Therefore, according to the tool changer 50 of the present embodiment, the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently. This makes it possible to suppress the prolongation of time during which processing cannot be performed.

[0088] In the present embodiment, the distance Db in the left-right direction between the storage slot 63 and the center arm 72 is the same as the distance Da in the left-right direction between the left hand 81L and the right hand 81R.

[0089] According to this configuration, when the other hand 81L (81R) is at the storage position Pc1, one hand 81R (81L) is at the change position Pc2. Consequently, by moving the left and right hands 81L, 81R by a certain distance in the left-right direction, the used center tool 32B can be removed from the center arm 72 with one hand 81R (81L) while the scheduled center tool 32A can be removed from the storage slot 63 with the other hand 81L (81R). In addition, directly to the center arm 72 from which the used center tool 32B is removed with one hand 81R (81L), the scheduled center tool 32A removed from the storage slot 63 can be mounted with the other hand 81L (81R). Thus, since the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently, it is possible to suppress the prolongation of time during which processing cannot be performed.

[0090] In the present embodiment, the left and right hands 81L and 81R are configured, respectively, to be movable in mutually approaching directions and mutually separating directions, and each hand includes left and right fingers 81b and 81c configured to hold the center tool 32 from both left and right sides, and the housing 81a on which the left and right fingers 81b and 81c are mounted. Each of the left and right fingers includes finger base 81b1, 81c1 extending diagonally upward away from the center of the hand, and the finger body 81b2, 81c2 extending forward from the finger base 81b1, 81c1 to hold the center tool 32.

[0091] According to this configuration, the housing 81a is disposed at the position relatively lower than the left and right finger bodies 81b2, 81c2. This allows for the suppression of situations where the center tool 32 stored in the storage slot 63 interferes with the housing 81a when the tool storage drum 60 is rotated.

[0092] In the present embodiment, the tool changer 50 further includes the control device configured to control the left and right hands.

[0093] According to this configuration, the control device 100 can control the left and right hands 81L and 81R to appropriately change the center tool 32.

[0094] In the present embodiment, the control device 100 controls the movement and positioning of the left and right hands 81L and 81R in the left-right direction to transition between three states. The three states include a state where one of the left and right hands 81L and 81R is at the storage position corresponding to the storage slot, the state where one hand 81R (81L) is at the change position Pc2 corresponding to the center arm 72, and the other hand 81L (81R) of the left and right hands 81L, 81R is at the storage position Pc1, and the state where the other hand 81L (81R) is at the change position Pc2.

[0095] According to this configuration, by transitioning the state of the left and right hands 81L and 81R just once, it is possible to remove the used center tool 32B from the center arm 72 with one hand 81R (81L) while mounting the scheduled center tool 32A to the center arm 72 with the other hand 81L (81R). Thus, since the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently, it is possible to suppress the prolongation of time during which processing cannot be performed.

[0096] In the present embodiment, the tool storage drum 60 is disposed at the position shifted to the left of the center tool unit 70. The control device 100 performs the following steps (1a) to (8a). (1a) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R from the state where the right hand 81R is at the storage position Pc1 to the state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1. (2a) Closing the left hand 81L, thereby holding, with the left hand 81L, the scheduled center tool 32A stored in the storage slot 63. (3a) Closing the right hand 81R, thereby holding, with the right hand 81R, the used center tool 32B mounted to the center arm 72 in the sprung-up state. (4a) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R to the state where the left hand 81L is at the change position Pc2. (5a) Opening the left hand 81L to hand over the scheduled center tool 32A to the center arm 72. (6a) Moving the left and right hands 81L and 81R to the left, thereby transitioning the left and right hands 81L and 81R to the state where the right hand 81R is at the storage position Pc1. (7a) Opening the right hand 81R to hand over the used center tool 32B to the storage slot 63. (8a) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R to the state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1.

[0097] According to this configuration, the left hand 81L manages the scheduled center tool 32A, and the right hand 81R manages the used center tool 32B. Consequently, during the movement of the left and right hands 81L and 81R to the right, it is possible to remove the used center tool 32B from the center arm 72 with the right hand 81R while mounting the scheduled center tool 32A to the center arm 72 with the left hand 81L. Thus, since the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently, it is possible to suppress the prolongation of time during which processing cannot be performed.(Second Embodiment)

[0098] Hereinafter, a tool changer 50 for a bending machine 1 according to a second embodiment and a tool changing method for the bending machine will be described. The configuration of the bending machine 1 and the tool changer 50 according to the second embodiment is the same as that of the first embodiment, but the flow of the tool changing method differs. Hereinafter, the differences from the first embodiment will be mainly described.

[0099] FIG. 12 is a diagram showing the tool changing method according to the second embodiment. In the tool changing method according to the second embodiment, since a process from step S10 to step S14 is the same as in the first embodiment, the description will start from a process of step S15a following step S14.

[0100] In step S15a, a control device 100 moves left and right hands 81L and 81R to the left and positions the left hand 81L and the right hand 81R at a storage position Pc1 and a change position Pc2, respectively.

[0101] In step S16a, the control device 100 rotates a tool storage drum 60 to position, at the lowest position of the drum, a storage slot 63 in which a new scheduled center tool 32C is stored. The control device 100 closes the left hand 81L and holds the new scheduled center tool 32C with the left hand 81L.

[0102] In step S17a, the control device 100 moves the left and right hands 81L and 81R to the left and positions the left hand 81L and the right hand 81R at a left standby position Pc3 and the storage position Pc1, respectively. During a process of positioning the left and right hands 81L and 81R, the new scheduled center tool 32C is pulled out from the storage slot 63, and a used center tool 32B is inserted into the storage slot 63.

[0103] In step S18a, the control device 100 opens the right hand 81R to hand over the used center tool 32B to the storage slot 63. Once the used center tool 32B is handed over, the control device 100 operates the tool storage drum 60 to place, at the lowest position of the drum, an empty storage slot 63 in which any center tool 32 is not stored.

[0104] In step S19a, the control device 100 moves the left and right hands 81L and 81R to the right and positions the left hand 81L and the right hand 81R at the storage position Pc1 and the change position Pc2, respectively. During a process of positioning the left hand 81L at the storage position Pc1, the new scheduled center tool 32C is temporarily inserted into the storage slot 63. Then, to perform a tool changing operation for the new scheduled center tool 32C, an operation of and after step S12 shown in the first embodiment is conducted.

[0105] In the present embodiment, the tool storage drum 60 is disposed at a position shifted to the left of a center tool unit 70. The control device 100 performs the following steps (1b) to (10b). (1b) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R from a state where the right hand 81R is at the storage position Pc1 to a state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1. (2b) Closing the left hand 81L, thereby holding, with the left hand 81L, a scheduled center tool 32A stored in the storage slot 63. (3b) Closing the right hand 81R, thereby holding, with the right hand 81R, the used center tool 32B mounted to a center arm 72 in a sprung-up state. (4b) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R to a state where the left hand 81L is at the change position Pc2. (5b) Opening the left hand 81L to hand over the scheduled center tool 32A to the center arm 72. (6b) Moving the left and right hands 81L and 81R to the left, thereby transitioning the left and right hands 81L and 81R to a state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1. (7b) Closing the left hand 81L, thereby holding, with the left hand 81L, a new scheduled center tool 32C in the storage slot 63. (8b) Moving the left and right hands 81L and 81R to the left, thereby transitioning the left and right hands 81L and 81R to a state where the right hand 81R is at the storage position Pc1. (9b) Opening the right hand 81R to hand over the used center tool 32B to the storage slot 63. (10b) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R to a state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1.

[0106] According to this configuration, the left hand 81L manages the scheduled center tool 32A and the right hand 81R manages the used center tool 32B in the same manner as in the first embodiment. Consequently, during the movement of the left and right hands 81L and 81R to the right, it is possible to remove the used center tool 32B from the center arm 72 with the right hand 81R while mounting the scheduled center tool 32A to the center arm 72 with the left hand 81L. Thus, since the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently, it is possible to suppress the prolongation of time during which processing cannot be performed.

[0107] In addition, the new scheduled center tool 32C can be held with the left hand 81L before the used center tool 32B is stored in the storage slot 63 with the right hand 81R. Consequently, the left hand 81L can smoothly receive the new scheduled center tool 32C.(Third Embodiment)

[0108] Hereinafter, a tool changer 50 for a bending machine 1 according to a third embodiment and a tool changing method for the bending machine will be described. The configuration of the bending machine 1 and the tool changer 50 according to the third embodiment is the same as that of the first embodiment, but the flow of the tool changing method differs. Specifically, in the first embodiment, the scheduled center tool 32A is managed by the left hand 81L, whereas in the third embodiment, a scheduled center tool 32A is managed by a right hand 81R. Hereinafter, the differences from the first embodiment will be mainly described.

[0109] With reference FIGS. 13 and 14, the tool changing method by the tool changer 50 will be described. FIGS. 13 and 14 are diagrams showing the tool changing method according to the third embodiment. This tool changing method is executed under the control of the control device 100.

[0110] As shown in FIG. 13, a state where the left hand 81L is at a left standby position Pc3 and the right hand 81R is at a change position Pc2 is defined as an initial state of the left and right hands 81L and 81R (S20). Currently, the left and right hands 81L and 81R are in an open state. Also, at a drum lowest position, an empty storage slot 63 is disposed in which any center tool 32 is not stored.

[0111] In step S21, the control device 100 rotates a tool storage drum 60 to position the storage slot 63 storing the scheduled center tool 32A at the lowest position of the drum. The control device 100 closes the right hand 81R and holds the scheduled center tool 32A with the right hand 81R.

[0112] In step S22, the control device 100 moves the left and right hands 81L and 81R to the right to position the left hand 81L and the right hand 81R at the change position Pc2 and a right standby position Pc4, respectively.

[0113] In step S23, the control device 100 causes a center arm 72 to which a used center tool 32B is mounted, to pivot into a sprung-up state. After the center arm 72 pivots, the control device 100 closes the left hand 81L and holds the used center tool 32B with the left hand 81L. The control device 100 pulls a piston 72c (see FIG. 7) upward to release the fixation of the used center tool 32B to the center arm 72.

[0114] In step S24 of FIG. 14, the control device 100 moves each of the left and right hands 81L and 81R to the left. At this time, the used center tool 32B is pulled out from the center arm 72. The control device 100 positions the left hand 81L and the right hand 81R to a storage position Pc1 and the change position Pc2, respectively. During a process of positioning the left hand 81L and the right hand 81R to the storage position Pc1 and the change position Pc2, respectively, the scheduled center tool 32A is inserted into the center arm 72, and the used center tool 32B is inserted into the storage slot 63. The control device 100 pulls the piston 72c (see FIG. 7) downward to fix the scheduled center tool 32A to the center arm 72.

[0115] In step S25, the control device 100 opens the right hand 81R to hand over the scheduled center tool 32A to the center arm 72. Once the scheduled center tool 32A is handed over, the control device 100 causes the center arm 72 to which the scheduled center tool 32A is mounted, to pivot into a reference state.

[0116] In step S26, the control device 100 opens the left hand 81L to hand over the used center tool 32B to the storage slot 63. Once the used center tool 32B is handed over, the control device 100 operates the tool storage drum 60 to place, at the lowest position of the drum, an empty storage slot 63 in which any center tool 32 is not stored. The processing in step S26 may be performed simultaneously with the processing in step S25.

[0117] In step S27, the control device 100 moves the left and right hands 81L and 81R to the left and positions the left hand 81L and the right hand 81R at the left standby position Pc3 and the storage position Pc1, respectively. Then, when performing a new tool changing operation, the operations of and after step S21 described above are repeated.

[0118] In the series of operations mentioned above, the processes of steps S20 to S22 and S26 to S27 are performed during a processing operation of the bending machine 1. In addition, the process of steps S23 to S25 is performed during a non-processing operation of the bending machine 1.

[0119] Thus, in the present embodiment, the tool storage drum 60 is disposed at a position shifted to the left of the center tool unit 70. The control device 100 performs each of processes (1c) to (7c) below. (1c) Closing the right hand 81R in a state where the right hand 81R is at the storage position Pc1, thereby holding, with the right hand 81R, the scheduled center tool 32A in the storage slot 63. (2c) Moving the left and right hands 81L and 81R to the right, thereby transitioning the left and right hands 81L and 81R to a state where the left hand 81L is at the change position Pc2. (3c) Closing the left hand 81L, thereby holding, with the left hand 81L, the used center tool 32B mounted to the center arm 72 in a sprung-up state. (4c) Moving the left and right hands 81L and 81R to the left, thereby transitioning the left and right hands 81L and 81R to a state where the right hand 81R is at the change position Pc2 and the left hand 81L is at the storage position Pc1. (5c) Opening the right hand 81R to hand over the scheduled center tool 32A to the center arm 72. (6c) Open the left hand 81L to hand over the used center tool 32B to the storage slot 63. (7c) Move the left and right hands 81L and 81R to the left, thereby transitioning the left and right hands 81L and 81R to a state where the right hand 81R is at the storage position Pc1.

[0120] According to this configuration, the right hand 81R can manage the scheduled center tool 32A, while the left hand 81L can manage the used center tool 32B. Consequently, there is no need to wait for the rotation of the tool storage drum 60, as is required when switching the center tool 32 with one hand. Additionally, during the movement of the left and right hands 81L and 81R to the left, the used center tool 32B can be removed from the center arm 72 with the left hand 81L, while the scheduled center tool 32A can be mounted on the center arm 72 with the right hand 81R. Thus, since the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently, it is possible to suppress the prolongation of time during which processing cannot be performed.

[0121] As above, the tool changer 50 for the bending machine 1 according to the first to third embodiments has been described. Furthermore, the tool changing method for the bending machine 1 also functions as part of the present embodiment. That is, the tool changer 50 for the bending machine 1 includes the tool storage drum 60 including the plurality of storage slots 63 capable of respectively storing the plurality of center tools 32 having different lengths, the center tool unit 70 including the center arm 72 to which the center tool 32 is mountable, and configured to be switchable, by pivoting of the center arm 72 about the rotation axis A1 extending in the left-right direction, between the reference state where the center tool 32 is aligned as a part of the top die 30 and the sprung-up state where the center tool 32 is changeable, and the transfer unit including the left hand 81L and the right hand 81R arranged side by side in the left-right direction to move in the left-right direction while maintaining the distance between the left hand and the right hand, and configured to transfer the center tool between the storage slot and the center arm arranged on the extension line of the movement direction of the left and right hands 81L and 81R. This tool changing method involves changing the center tool between the storage slot 63 and the center arm 72, while transitioning the left and right hands 81L, 81R to three states including the state where one hand 81R (81L) of the left and right hands 81L and 81R is at the storage position Pc1 corresponding to the storage slot 63, the state where the one hand 81R (81L) is at the change position Pc2 corresponding to the center arm 72, and the other hand 81L (81R) of the left and right hands 81L, 81R is at the storage position Pc1, and the state where the other hand 81L (81R) is at the change position Pc2.

[0122] According to the tool changing method of the present embodiment, the storage slot 63 and the center arm 72 are arranged on the extension line of the movement direction of the left and right hands 81L and 81R. Consequently, the left and right hands 81L and 81R can each hold the used center tool 32B and the scheduled center tool 32A, respectively, so there is no need to wait for the rotation of the tool storage drum 60.

[0123] In addition, only by transitioning the state of the left and right hands 81L and 81R once, the used center tool 32B can be removed from the center arm 72 with one hand 81R (81L) while mounting the scheduled center tool 32A to the center arm 72 with the other hand 81L (81R).

[0124] Therefore, according to the tool changing method of the present embodiment, the changing operation of the center tool 32 with respect to the center arm 72 can be performed efficiently. Consequently, it is possible to suppress the prolongation of time during which processing cannot be performed.

[0125] In each of the embodiments described above, the tool storage drum 60 is disposed at the position shifted to the left of the center tool unit 70. However, the tool storage drum 60 may be disposed at a position shifted to the right of the center tool unit 70. In this case, in the tool changing method, the movements of the left and right hands 81L and 81R described in the first to third embodiments can be interchanged.

[0126] As above, the present embodiment has been described, and it should not be understood that the discussions and drawings that form part of the embodiment limit the embodiment. This embodiment will reveal various alternative forms of implementation, examples, and operational techniques to those skilled in the art.

[0127] The disclosure of this application relates to the subject matter described in Japanese Patent Application No. 2023-097656, filed with the Japan Patent Office on June 14, 2023, and all its disclosures are incorporated herein by reference.

Examples

first embodiment

(First Embodiment)

[0013]First, with reference to FIGS. 1 to 3, an overview of a bending machine 1 according to the first embodiment will be described. FIG. 1 is a diagram showing the main part of a tool changer according to the present embodiment. FIG. 2 is a front view showing the bending machine according to the present embodiment. FIG. 3 is a side view showing the bending machine according to the present embodiment. In describing the configuration of the bending machine 1, as directions, left-right, front-rear, and up-down directions are defined for use. The left-right direction and front-rear direction correspond to two directions that are orthogonal in a horizontal plane, while the up-down direction corresponds to a perpendicular direction. In the drawings, rightward, leftward, upward, downward, forward, and rearward are indicated as RT, LT, UP, DN, FR, and RR, respectively. However, these directions are merely conveniently defined directions for describing a processing machine...

second embodiment

(Second Embodiment)

[0098]Hereinafter, a tool changer 50 for a bending machine 1 according to a second embodiment and a tool changing method for the bending machine will be described. The configuration of the bending machine 1 and the tool changer 50 according to the second embodiment is the same as that of the first embodiment, but the flow of the tool changing method differs. Hereinafter, the differences from the first embodiment will be mainly described.

[0099]FIG. 12 is a diagram showing the tool changing method according to the second embodiment. In the tool changing method according to the second embodiment, since a process from step S10 to step S14 is the same as in the first embodiment, the description will start from a process of step S15a following step S14.

[0100]In step S15a, a control device 100 moves left and right hands 81L and 81R to the left and positions the left hand 81L and the right hand 81R at a storage position Pc1 and a change position Pc2, respectively.

[0101]In...

third embodiment

(Third Embodiment)

[0108]Hereinafter, a tool changer 50 for a bending machine 1 according to a third embodiment and a tool changing method for the bending machine will be described. The configuration of the bending machine 1 and the tool changer 50 according to the third embodiment is the same as that of the first embodiment, but the flow of the tool changing method differs. Specifically, in the first embodiment, the scheduled center tool 32A is managed by the left hand 81L, whereas in the third embodiment, a scheduled center tool 32A is managed by a right hand 81R. Hereinafter, the differences from the first embodiment will be mainly described.

[0109]With reference FIGS. 13 and 14, the tool changing method by the tool changer 50 will be described. FIGS. 13 and 14 are diagrams showing the tool changing method according to the third embodiment. This tool changing method is executed under the control of the control device 100.

[0110]As shown in FIG. 13, a state where the left hand 81L is...

Claims

1. A tool changer for a bending machine, mounted on the bending machine comprising an upper frame provided with a top die including a center tool and configured to be movable in an up-down direction, and a lower frame provided with a bottom die opposing the top die, the bending machine configured to bend a workpiece while the workpiece is fixed between the top die and the bottom die, the tool changer comprising: a tool storage device including a plurality of storage slots capable of respectively storing a plurality of center tools having different lengths, a center tool unit including a center arm to which the center tool is mountable, and configured to be switchable, by pivoting of the center arm about a rotation axis extending in a left-right direction, between a reference state where the center tool is aligned as a part of the top die and a sprung-up state where the center tool is changeable, and a transfer unit including left and right hands arranged side by side in the left-right direction and configured to move in the left-right direction while maintaining a distance between the left hand and the right hand, the transfer unit configured to transfer the center tool between a storage slot and the center arm arranged on an extension line of a movement direction of the left and right hands, the movement direction of the left and right hands corresponding to a direction in which the center tool is inserted / removed into / from the storage slot and the center arm.

2. The tool changer for the bending machine according to claim 1, wherein a distance between the storage slot and the center arm in the left-right direction is the same as the distance between the left hand and the right hand in the left-right direction.

3. The tool changer for the bending machine according to claim 1, wherein each of the left and right hands includes: left and right fingers configured to be movable in mutually approaching directions and mutually separating directions, and configured to hold the center tool from both left and right sides, and a housing on which the left and right fingers are mounted, and each of the left and right fingers includes: a finger base extending diagonally upward away from a hand center, and a finger body configured to extend forward from the finger base and hold the center tool.

4. The tool changer for the bending machine according to claim 1, further comprising a control device configured to control the left and right hands.

5. The tool changer for the bending machine according to claim 4, wherein the control device controls movement in the left-right direction and positioning of the left and right hands to transition between three states, and the three states includes: a state where one hand of the left and right hands is at a storage position corresponding to the storage slot, a state where the one hand is at a change position corresponding to the center arm, and the other hand of the left and right hands is at the storage position, and a state where the other hand is at the change position.

6. The tool changer for the bending machine according to claim 5, wherein the tool storage device is disposed at a position shifted to the left of the center tool unit, and the control device is configured to: move the left and right hands to the right, thereby transitioning the left and right hands from a state where the right hand is at the storage position to a state where the right hand is at the change position and the left hand is at the storage position, close the left hand, thereby holding, with the left hand, a scheduled center tool stored in the storage slot, close the right hand, thereby holding, with the right hand, a used center tool mounted to the center arm in the sprung-up state, move the left and right hands to the right, thereby transitioning the left and right hands to a state where the left hand is at the change position, open the left hand to hand over the scheduled center tool to the center arm, move the left and right hands to the left, thereby transitioning the left and right hands to a state where the right hand is at the storage position, open the right hand to hand over the used center tool to the storage slot, and move the left and right hands to the right, thereby transitioning the left and right hands to a state where the right hand is at the change position and the left hand is at the storage position.

7. The tool changer for the bending machine according to claim 5, wherein the tool storage device is disposed at a position shifted to the left of the center tool unit, and the control device is configured to: move the left and right hands to the right, thereby transitioning the left and right hands from a state where the right hand is at the storage position to a state where the right hand is at the change position and the left hand is at the storage position, close the left hand, thereby holding, with the left hand, a scheduled center tool stored in the storage slot, close the right hand, thereby holding, with the right hand, a used center tool mounted to the center arm in the sprung-up state, move the left and right hands to the right, thereby transitioning the left and right hands to a state where the left hand is at the change position, open the left hand to hand over the scheduled center tool to the center arm, move the left and right hands to the left, thereby transitioning the left and right hands to a state where the right hand is at the change position and the left hand is at the storage position, close the left hand, thereby holding, with the left hand, a new scheduled center tool in the storage slot, move the left and right hands to the left, thereby transitioning the left and right hands to a state where the right hand is at the storage position, open the right hand to hand over the used center tool to the storage slot, and move the left and right hands to the right, thereby transitioning the left and right hands to a state where the right hand is at the change position and the left hand is at the storage position.

8. The tool changer for the bending machine according to claim 5, wherein the tool storage device is disposed at a position shifted to the left of the center tool unit, and the control device is configured to: close the right hand in a state where the right hand is at the storage position, thereby holding, with the right hand, a scheduled center tool in the storage slot, move the left and right hands to the right, thereby transitioning the left and right hands to a state where the left hand is at the change position, close the left hand, thereby holding, with the left hand, a used center tool mounted to the center arm in the sprung-up state, move the left and right hands to the left, thereby transitioning the left and right hands to a state where the right hand is at the change position and the left hand is at the storage position, open the right hand to hand over the scheduled center tool to the center arm, open the left hand to hand over the used center tool to the storage slot, and move the left and right hands to the left, thereby transitioning the left and right hands to a state where the right hand is at the storage position.

9. A tool changing method for a bending machine, the bending machine comprising an upper frame provided with a top die including a center tool and configured to be movable in an up-down direction, and a lower frame provided with a bottom die opposing the top die, the bending machine being configured to bend a workpiece while the workpiece is fixed between the top die and the bottom die, a tool changer of the bending machine comprising: a tool storage device including a plurality of storage slots capable of respectively storing a plurality of center tools having different lengths, a center tool unit including a center arm to which the center tool is mountable, and configured to be switchable, by pivoting of the center arm about a rotation axis extending in a left-right direction, between a reference state where the center tool is aligned as a part of the top die and a sprung-up state where the center tool is changeable, and a transfer unit including left and right hands arranged side by side in the left-right direction and configured to move in the left-right direction while maintaining a distance between the left hand and the right hand, the transfer unit configured to transfer the center tool between the storage slot and the center arm arranged on an extension line of a movement direction of the left and right hands, the tool changing method comprising: changing, with the left and right hands, the center tool between the storage slot and the center arm while transitioning between three states including: a state where one hand of the left and right hands is at a storage position corresponding to the storage slot, a state where the one hand is at a change position corresponding to the center arm, and the other hand of the left and right hands is at the storage position, and a state where the other hand is at the change position.

Images