Workpiece holding device and work-piece holding method

Abstract

To position a workpiece accurately and perform work for mounting an extension member for holding the workpiece simply.SOLUTION: A pair of rotary positioners 25A and 25B provided which a workpiece holding device 100 has comprise an annular holding part 27 that holds a workpiece W and a support part that supports the annular holding part 27 rotatably. The annular holding part 27 comprises a pair of first fixing mechanisms 39A and 39C that fix the workpiece W while pinching the workpiece in a first direction D1 along a radial direction of the annular holding part 27, and a pair of second fixing mechanisms 39B and 39D that fix the workpiece W while pinching the workpiece W in a second direction D2 that is orthogonal to the first direction D1. Either of the first fixing mechanisms comprises a placement base 41 on which the work-piece W is placed. The placement base 41 is provided with a butting member 43 having a butting part 44 which the workpiece W butts against and a fixing part 45 that positions the butting member 43 in a direction in which the member approaches or gets away from the workpiece W.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a workpiece holding device and a workpiece holding method that hold a workpiece in any posture. [Background technology]

[0002] A known conventional workpiece holding device is a rotary positioner that rotates an annular holding part that holds a workpiece such as a steel material on its inner circumference to change the position of the workpiece held by the rotary drive part (Patent Document 1). This rotary positioner is equipped with four fixing mechanisms that hold the workpiece by pressing it against the radial direction of the annular holding part. The fixing mechanisms are provided with dedicated fixing jigs or with dedicated attachments that are suitable for the type and size of the steel material (e.g., H-shaped steel, square steel pipe, etc.).

[0003] When the rotating positioner of the above-mentioned Patent Document 1 holds an H-shaped steel workpiece, in consideration of the storage and transportation of the workpiece in the factory, one flange of the workpiece is placed on the mounting table, and the web of the workpiece is often pressed against it from the left and right directions by a fixing mechanism that can move forward and backward in the radial direction of the annular holding part. In this case, the other flange is pressed against it from the top and bottom directions. In this way, the workpiece is clamped and held from a total of four directions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5883700 Summary of the Invention [Problem to be solved by the invention]

[0005] When a workpiece is held by the rotary positioner as described above, it is necessary to align the workpiece with the center of rotation of the annular holding part. In the case of a column-type or pipe-type workpiece, the left-right fixing mechanisms are positioned near the workpiece in advance, and the workpiece is lowered to a predetermined holding position using the positions of these fixing mechanisms as an index, and then placed on the mounting table. This makes it easy to position the workpiece left-right on the mounting table.

[0006] However, when the workpiece is an H-shaped steel, the pair of wide flanges must be lowered to a specified holding position with the flanges facing up and down, and the fixing members in the left and right directions must be spaced apart so as not to interfere with the lower flanges. Therefore, when the workpiece is lowered to the desired holding position, there is no position indicator, making it difficult to position the workpiece in the left and right directions on the mounting table.

[0007] In addition, after placing the workpiece in a predetermined holding position on the mounting table, it is necessary to attach extension members that extend the left and right fixing members inward. In this case, the installation work of the extension members is complicated, such as supporting a heavy member and screwing it in at multiple points, and this places a heavy burden on the worker.

[0008] Therefore, the present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide a work holding device and a work holding method that can position the workpiece with high precision and easily perform the installation work of an extension member for holding the workpiece. [Means for solving the problem]

[0009] The present invention comprises the following configurations. (1) A work holding device having a pair of rotation positioners that holds both ends of a long workpiece and rotates the workpiece to place the workpiece in an arbitrary position, The rotational positioner includes: An annular holding portion that is formed in an annular shape and holds the workpiece radially inward in a position in which the radial direction of the annular ring is oriented vertically; a support portion that supports the annular holding portion rotatably around an axial direction of the ring; Equipped with The annular holding portion is A pair of first fixing mechanisms are provided on the inner peripheral side of the annular ring, and advance and retreat in a first direction along a radial direction of the annular holding portion to clamp and fix the workpiece in the first direction; A pair of second fixing mechanisms each move forward and backward in a second direction perpendicular to the first direction and along a radial direction of the annular holding portion to clamp and fix the workpiece in the second direction; Equipped with One of the pair of first fixing mechanisms is a base fixing mechanism including a mounting table having a mounting surface on which the work is placed and which is movable in a radial direction of the annular holding portion, The mounting table has: A butting member extending upward from the mounting table and having a butting portion against which the workpiece butts; a fixing portion that positions the abutting member along the placement surface in a direction toward or away from the workpiece and fixes the abutting member to the placement table; It is provided with Work holding device. (2) A method for holding a long workpiece by rotating the workpiece while holding both ends of the workpiece with a pair of rotary positioners, the method comprising the steps of: The rotational positioner includes: The workpiece is held radially inward in a position in which the radial direction of the ring is oriented vertically, and the workpiece is supported rotatably around the axial direction of the ring. The annular holding portion is A pair of first fixing mechanisms are provided on the inner peripheral side of the annular ring, and advance and retreat in a first direction along a radial direction of the annular holding portion to clamp and fix the workpiece in the first direction; A pair of second fixing mechanisms each move forward and backward in a second direction perpendicular to the first direction and along a radial direction of the annular holding portion to clamp and fix the workpiece in the second direction; Equipped with One of the pair of first fixing mechanisms is a base fixing mechanism including a mounting table having a mounting surface on which the workpiece is placed that is movable in a radial direction of the annular holding portion, A butting member having an butting portion that extends upward from the mounting table and butts against the work is positioned and fixed to the mounting table in a direction approaching or receding from the work along the mounting surface; When placing the workpiece on the placement table, the workpiece is lowered while being brought into contact with the abutment portion, and placed on the placement table. Workpiece holding method. Effect of the Invention

[0010] According to the present invention, the workpiece can be positioned with high accuracy, and the attachment work of the extension member for holding the workpiece can be easily performed. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a workpiece holding device provided in a welding system. [Diagram 2] FIG. 2 is a schematic configuration diagram of a main part of the rotary positioner as viewed from the side. [Diagram 3] FIG. 3 is a partially enlarged view of the mounting table to which the abutment members are fixed. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is a schematic perspective view of a mounting table to which an abutment member is fixed. [Figure 6] FIG. 6 is an exploded perspective view of the abutment member and the guide plate. [Figure 7] FIG. 7 is a schematic diagram showing a state in which a workpiece smaller than the workpiece shown in FIG. 2 is held by a rotary positioner. [Figure 8A] FIG. 8A is a schematic diagram showing the operation of the rotation positioner, and is an operation explanatory diagram showing a state in which the arc portion 27a of the annular holding portion is released. [Figure 8B] FIG. 8B is a schematic diagram showing the operation of the rotary positioner, and is an operation explanatory diagram showing a state in which a workpiece is accommodated in the inner peripheral portion of the annular holding portion. [Figure 8C]FIG. 8C is a schematic diagram showing the operation of the rotary positioner, and is an explanatory diagram showing a state in which the arc portion of the annular holding portion is closed to hold the workpiece. [Figure 9] FIG. 9 is a schematic diagram showing a state in which the annular holding portion is rotated. [Figure 10] FIG. 10 is a cross-sectional view of a fixing mechanism to which the first extension member and the second extension member are attached. [Figure 11] FIG. 11 is a perspective view of the first extension member. [Figure 12] FIG. 12 is a perspective view of the second extension member. [Figure 13] FIG. 13 is an explanatory diagram, partly in section, showing in a step-by-step manner a procedure for attaching the second extension member to the first extension member fixed to the fixing mechanism. [Figure 14] FIG. 14 is a schematic cross-sectional view showing another joining mode between the first extension member and the second extension member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. A work holding device according to the present invention will be described having a configuration including a pair of rotation positioners that rotates a long workpiece while holding both ends of the workpiece when welding the workpiece, and puts the workpiece in an arbitrary position. However, the configuration shown here is merely an example, and the present invention is not limited to this embodiment, and can be applied to applications other than welding.

[0013] <Work holding device> 1 is a schematic diagram of a workpiece holding device 100 provided in a welding system 200. Welding system 200 includes workpiece holding device 100 and a welding device 300. Welding device 300 includes rails 11, a welding carriage 13 that moves on rails 11, a welding robot 15 mounted on welding carriage 13, and a welding control device 17, and further includes a welding power source, a welding wire supply, etc., which are not shown.

[0014] A welding torch 19 is provided at the tip of the arm of the welding robot 15. A welding wire (not shown) is fed to the welding torch 19, and power for welding is supplied between the welding wire and the workpiece W. This generates an arc at the tip of the welding wire, making it possible to weld the workpiece W. This welding device 300 makes it possible to weld any position on the workpiece W by controlling the movement of the welding carriage 13 and the position and posture of the welding torch 19 by the welding robot 15.

[0015] The workpiece holding device 100 includes a rail 21, a pair of workpiece carriages 23A, 23B that move on the rail 21, and rotary positioners 25A, 25B mounted on the workpiece carriages 23A, 23B, respectively. The pair of rotary positioners 25A, 25B hold the workpiece W at positions spaced apart from each other in the longitudinal direction of the workpiece W along the rail 21. The holding positions of the workpiece W by the rotary positioners 25A, 25B can be adjusted by moving the workpiece carriages 23A, 23B.

[0016] <Rotational positioner> The rotary positioners 25A, 25B have an annular holding portion 27, a support portion 29, and a lifting arm mechanism 31. The annular holding portion 27 is formed in an annular shape and holds the workpiece W on the radially inner side in an orientation in which the radial direction of the annular ring faces the vertical direction. The support portion 29 supports the annular holding portion 27 rotatably around the axial direction of the annular ring.

[0017] The workpiece carriages 23A and 23B are provided below the rotary positioners 25A and 25B, respectively, and enable the rotary positioners 25A and 25B to move along the rails 21.

[0018] For example, the rotary positioners 25A and 25B do not rotate the workpiece W when the welding robot 15 is welding a straight portion of the workpiece W, and rotate the workpiece W when the welding robot 15 is welding an arc portion (corner portion) of the workpiece W. This makes it possible to perform continuous welding without interrupting the arc not only on the straight portion of the workpiece W but also on the arc portion.

[0019] FIG. 2 is a schematic diagram of the main parts of the rotary positioners 25A and 25B seen from the side. The annular holding part 27 holds the workpiece W in the inner peripheral part S of the annular ring. A gear 33 is formed on the outer periphery of the annular holding part 27. The support part 29 has a pinion gear 35 that meshes with the gear 33. The pinion gear 35 is connected to a rotary drive part 37 such as a motor, and is rotated by the rotary drive part 37. The rotation of the pinion gear 35 is transmitted to the gear 33, which rotates the annular holding part 27. The rotary drive part 37 may be provided in at least one of the pair of rotary positioners 25A and 25B, and the other rotary positioner may be driven by the rotation of the other rotary positioner. In addition, the rotary drive part 37 may be provided in both rotary positioners 25A and 25B, and both may be controlled synchronously.

[0020] <Fixing mechanism> Four fixing mechanisms 39A, 39B, 39C, and 39D for holding the workpiece W are provided on the inner periphery S of the annular holding portion 27. Here, the up-down direction (vertical direction) in the rotation position of the annular holding portion 27 shown in FIG. 2 is defined as a first direction D1, and the left-right direction (horizontal direction) perpendicular to the first direction D1 is defined as a second direction D2. In addition, the direction perpendicular to the first direction D1 and the second direction D2 is defined as a third direction D3 (see FIG. 1). The third direction D3 is the axial direction of the ring of the annular holding portion 27.

[0021] The workpiece W is, for example, an H-shaped steel, and has a pair of flanges Wf and a web Ww connecting the pair of flanges Wf. Generally, the workpiece W is often stored and transported with the flanges Wf oriented vertically, so when the workpiece W is held by the rotary positioners 25A and 25B, it is preferable to hold the workpiece W in an orientation in which the pair of flanges Wf are oriented vertically.

[0022] Among the fixing mechanisms 39A, 39B, 39C, and 39D possessed by the annular holding portion 27, the fixing mechanisms 39A and 39C are first-direction fixing mechanisms that advance and retreat in a first direction D1 along the radial direction of the annular holding portion 25, and sandwich and fix the workpiece W in the first direction. The fixing mechanisms 39B and 39D are second-direction fixing mechanisms that advance and retreat in a second direction D2, and sandwich and fix the workpiece W in the second direction D2. The annular holding portion 27 holds the workpiece W by sandwiching it from four sides perpendicular to the longitudinal direction of the rail 21 with the multiple fixing mechanisms 39A, 39B, 39C, and 39D. The tips of the multiple fixing mechanisms 39A, 39B, and 39D come into contact with the workpiece W.

[0023] In the rotational position of the annular holding part 27 shown in FIG. 2, the fixing mechanism 39C arranged at the lowest position includes a mounting table 41 having a mounting surface 41a on which the workpiece W is placed and which is movable in the radial direction of the annular holding part 27. Hereinafter, this fixing mechanism 39C is also referred to as a base fixing mechanism. A butting member 43 is fixed to the mounting table 41 of the base fixing mechanism by a fixing part 45. The butting member 43 has a standing part 43a that extends toward the upper side (vertical direction) of the mounting table 41 and has a butting part 44, the details of which will be described later, and a bottom part 43b that extends along the mounting surface 41a perpendicular to the extending direction of the standing part 43a. The butting member 43 shown here is a plate-like body formed in an L-shape in a side view, but the shape is not limited to this. The standing part 43a extends toward the upper side of the mounting surface 41a to a height H that is 100 mm or more. The abutting portion 44 is, for example, a flat surface extending in the first direction D1. The fixing portion 45 positions the abutting member 43 along the mounting surface 41a in a direction approaching or receding from the workpiece W, i.e., in a predetermined position in the second direction D2, and fixes the abutting member 43 to the mounting table 41.

[0024] When the workpiece W is placed on the placement table 41, the abutment member 43 lowers the workpiece W while bringing it into contact with the abutment portion 44 of the standing portion 43a, thereby positioning the workpiece W at a predetermined position in the second direction D2.

[0025] <Lifting arm mechanism> 1 and 2, the rotary positioners 25A and 25B are equipped with a lifting arm mechanism 31 that cuts off a portion of the annular holding portion 27 to open and close it. The lifting arm mechanism 31 cuts off a predetermined region of the annular holding portion 27, which in this configuration is a circular arc portion 27a that is the shorter arc from position P1 to position P2, to allow it to be opened and closed. The lifting arm mechanism 31 separates the circular arc portion 27a of the annular holding portion 27 from the remaining portion 27b of the annular holding portion 25, thereby enabling the workpiece W to be inserted from the outside of the annular holding portion 27 into the inner peripheral portion S.

[0026] <Abutment parts and fixing parts> Next, the abutment member 43 and the fixing portion 45 of the base fixing mechanism will be described in detail. 3 is a partial enlarged view of the mounting table 41 to which the abutment member 43 is fixed. The mounting table 41 is provided radially inside the annular holding portion 27 of the fixing mechanism 39C. The mounting table 41 is flat, and the tip of the fixing mechanism 39C is fixed to the back side surface of the mounting surface 41a. In addition, a pair of guide portions 51A, 51B are provided on both sides of the fixing mechanism 39C of the mounting table 41 so as to be movable forward and backward in the first direction D1.

[0027] The guide portions 51A and 51B have a cylindrical main body portion 55 fixed to an attachment base portion 53C integrated with the annular holding portion 27, and a leg portion 57 fitted into an inner peripheral surface of the main body portion 55. One end of the leg portion 57 is fixed to the mounting table 41 similarly to the fixing mechanism 39C. The guide portions 51A and 51B guide the mounting table 41 such that the mounting surface 41a of the mounting table 41 moves in parallel in response to the displacement of the fixing mechanism 39C in the first direction D1.

[0028] Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3. Fig. 5 is a schematic perspective view of the mounting table 41 to which the abutting member 43 is fixed. As shown in Figs. 4 and 5, a flat guide plate 61 is fixed to one end of the mounting table 41 in the arrangement direction of the fixing mechanism 39C and the guide parts 51A and 51B. The guide plate 61 is fixed to the mounting surface 41a of the mounting table 41 by a plurality of bolts 59, and its plate surface is parallel to the mounting surface 41a. The guide plate 61 protrudes in the third direction D3 by a length L1 from the left end of the mounting table 41 shown in Fig. 4.

[0029] 6 is an exploded perspective view of the abutment member 43 and the guide plate 61. A groove 63 is formed in the bottom 43b of the abutment member 43, the groove 63 being recessed in the plate thickness direction and extending along the second direction D2. A long hole 65 is formed in the groove bottom surface 63a of the groove 63, which is a through hole along the longitudinal direction of the groove 63. The groove 63 is formed such that the groove width Lg in the first direction D1 is equal to or slightly smaller than the plate thickness tg of the guide plate 61. As a result, the protruding end 61a of the guide plate 61 is fitted in a state where it is sandwiched by the groove 63 in the plate thickness direction.

[0030] The abutment member 43 is fixed to the guide plate 61 by bolts 67. The guide plate 61 has a plurality of screw holes 69 formed in an end face of the protruding end portion 61a, and the bolts 67 are screwed into the screw holes 69 of the guide plate 61 through elongated holes 65 of the abutment member 43. By appropriately selecting a hole to be used for fixing from the plurality of screw holes 69, the attachment position of the abutment member 43 in the second direction D2 can be changed. In addition, the elongated holes 65 enable fine adjustment of the position in the second direction D2 of the abutment member 43 attached at the position of the selected screw hole 69.

[0031] The worker can measure the mounting position of the abutting member 43 by using a scale 71 and an indicator 73 shown in FIG. 5. The scale 71 is provided on the bottom 43b of the abutting member 43 along the second direction D2. As shown in FIG. 4, the indicator 73 is a plate whose base end is fixed to the guide plate 61 by a bolt 59, bent so as to straddle the bottom 43b of the abutting member 43, and whose tip is provided so as to point to the graduations of the scale 71. The scale 71 and the indicator 73 function as a position measuring unit 75 that measures the position of the abutting member 43 in the second direction D2. The position measuring unit 75 enables the abutting portion 44 of the abutting member 43 to be accurately positioned according to the workpiece W. The scale 71 and the indicator 73 may be provided on the guide plate 61 and the indicator 73 on the abutting member 43.

[0032] The mounting position of the abutting member 43 is changed according to the size and shape of the workpiece W held by the rotary positioners 25A and 25B. Fig. 7 is a schematic diagram showing a state in which a workpiece Wa, which is smaller in size than the workpiece W shown in Fig. 2, is held by the rotary positioner. When holding the workpiece Wa, the height of the mounting table 41 is changed by the fixing mechanism 39C, or an attachment 77 as shown in Fig. 7 is placed on the mounting table 41, so that the center position of the workpiece Wa coincides with the rotation center O of the annular holding part 27. In this case as well, by placing the workpiece Wa on the attachment 77 while contacting the abutment part 44 of the abutment member 43, the positioning of the workpiece Wa in the second direction D2 can be accurately performed.

[0033] <Rotational positioner operation> Next, the operation of the rotary positioners 25A and 25B will be described. Here, the operation of holding the workpiece Wa shown in Fig. 7 on the rotary positioners 25A and 25B will be exemplified. In this procedure, the web Ww of the workpiece Wa, which is an H-shaped steel, is mounted on the workpiece holding device 100 in a posture along the vertical direction.

[0034] 8A, 8B, and 8C are schematic diagrams showing the operation of rotary positioners 25A and 25B, and Fig. 8A is an explanatory diagram showing a state in which arc portion 27a of annular holding portion 27 is opened. Fig. 8B is an explanatory diagram showing a state in which workpiece Wa is accommodated in inner peripheral portion S of annular holding portion 27. Fig. 8C is an explanatory diagram showing a state in which arc portion 27a of annular holding portion 27 is closed to hold workpiece Wa.

[0035] First, before the workpiece Wa is loaded onto the workpiece holding device 100, the annular holding portion 27 is rotated by the rotation drive portion 37 to align the first direction D1 with the vertical direction as shown in FIG. 2 (pre-loading rotation process).

[0036] 8A, the worker uses the lifting arm mechanism 31 to lift the arc portion 27a that divides the annular holding portion 27 at a predetermined position, and separates it from the remaining portion 27b of the annular holding portion 27 (arrow PS1). This makes the workpiece Wa available for storage in the inner peripheral portion S (releasing process).

[0037] Then, the handle portion 89 of the fixing mechanism 39C is rotated to adjust the height of the mounting table 41 according to the size of the workpiece Wa to be mounted. This operation also includes the operation of adding an attachment 77 as necessary (height adjustment process).

[0038] Next, the handle portions 89 of the fixing mechanisms 39A, 39B, and 39D are rotated to adjust the tip positions of the fixing mechanisms 39A, 39B, and 39D so as not to interfere with the workpiece Wa to be mounted (jig avoidance process). Note that in this procedure, the first extension members 81 are attached to the fixing mechanisms 39A, 39B, and 39D in advance in consideration of the size of the workpiece Wa to be mounted, but the attachment may be performed at another timing, such as after the closing process described later.

[0039] Then, the workpiece Wa is inserted into the inner periphery S of the annular holding part 27 along the arrow PS2 while being suspended by a crane or the like (not shown). At this time, as shown in FIG. 8B, the workpiece Wa is lowered along the arrow PS3 while the lower flange Wf of the workpiece Wa is brought into contact with the abutment part 44 of the abutment member 43, and the lower flange Wf of the workpiece Wa is placed on the attachment 77 (placement process). Note that, depending on the workpiece Wa to be held, a placement position of the abutment member 43 where the center position of the workpiece Wa coincides with the rotation center of the annular holding part 27 is determined in advance, and the abutment member 43 is positioned so that the workpiece Wa is placed at the placement position. The abutment member 43 is placed at a position that does not interfere with the operation of placing the workpiece Wa on the attachment 77 and the operation of pressing the workpiece Wa by the fixing mechanisms 39B and 39D described later.

[0040] As described above, the worker brings at least a part of the workpiece Wa into contact with the abutment portion 44 before the workpiece Wa is placed on the attachment 77 or the mounting table 41. Then, the worker places the workpiece Wa on the attachment 77 or the mounting table 41 while maintaining the contact state. When the workpiece Wa comes into contact with the abutment portion 44, the abutment member 43 is positioned at a position where the center of the workpiece Wa coincides with the rotation center O of the annular holding portion 27 in the second direction D2. In other words, by placing the workpiece Wa on the attachment 77 or the mounting table 41 while keeping the workpiece Wa in contact with the abutment portion 44, the workpiece Wa is positioned at the rotation center O of the annular holding portion 27 in the second direction D2. The contact of the workpiece Wa with the abutment portion 44 is performed simultaneously or sequentially by each of the rotary positioners 25A and 25B shown in FIG. 1.

[0041] 8C, the arc portion 27a of the annular holding portion 27 is closed as indicated by the arrow PS3 (closing step). Then, the second extension member 83 is attached to the first extension member 81 of the fixing mechanisms 39B and 39D (extension member attachment step). The first extension member 81 and the second extension member 83 will be described in detail later.

[0042] Then, the upper flange Wf of the workpiece Wa is pressed by the fixing mechanism 39A, and the workpiece Wa is sandwiched between the fixing mechanism 35A and the attachment 77 on the mounting table 41. Furthermore, the tips of the second extension members 83 attached to the fixing mechanisms 39B and 39D are pressed against the web Ww of the workpiece Wa, and the workpiece Wa is sandwiched between the fixing mechanisms 39B and 39D. As a result, the workpiece Wa is sandwiched and held in the first direction D1 and the second direction D2 by the four fixing mechanisms 39A, 39B, 39C, and 39D (clamping process).

[0043] In this manner, the annular holding portion 27 is rotated with the workpiece Wa held by the annular holding portion 27, and the attitude of the workpiece Wa can be changed to any desired position. 9 is a schematic diagram showing a state in which the annular holding part 27 is rotated. The annular holding part 27 is rotated (PS4) by driving the pinion gear 35 to rotate, and this allows the posture of the workpiece Wa to be freely changed. The direction of rotation can be freely controlled in both forward and reverse directions.

[0044] <First extension member and second extension member to be attached to the fixing mechanism> Next, a detailed description will be given of the pair of second fixing mechanisms 39B and 39D that sandwich the workpiece Wa in the direction (second direction D2) perpendicular to the clamping direction (first direction D1) of the workpiece Wa by the fixing mechanism 39C that serves as the base fixing mechanism. The fixing mechanisms 39B and 39D have different mounting positions but the structure itself is the same, so here, the fixing mechanism 39B will be described as an example. The fixing mechanism 39D has a structure in which the fixing mechanism 39B is inverted in the second direction D2.

[0045] FIG. 10 is a cross-sectional view of the fixing mechanism 39B to which the first extension member 81 and the second extension member 83 are attached. The fixing mechanism 39B includes a nut portion 85, a screw shaft 87, a handle portion 89, and a contact portion 91. The nut portion 85 is fixed to the mounting base portion 53B of the annular holding portion 27. The screw shaft 87 is engaged with the nut portion 85 and can be extended and retracted toward the radially inner side of the annular holding portion 27, which is the second direction D2. The handle portion 89 is provided at the tip of the screw shaft 87 on the radially inner side of the annular holding portion 27. The handle portion 89 is rotated by an operator to rotate the screw shaft 87 and move the screw shaft 87 in the radial direction. The contact portion 91 is fixed to the screw shaft 87 together with the handle portion 89 by a bolt 92.

[0046] The fixing mechanism 39B of this configuration further includes a first extension member 81 whose base end side is removably connected to the contact portion 91 of the fixing mechanism 39B, and a second extension member 83 whose base end side is removably connected to the tip of the first extension member 81 opposite the base end side.

[0047] FIG. 11 is a perspective view of the first extension member 81. The first extension member 81 has a first extension connecting portion 93 connected to the contact portion 91 shown in FIG. 10, a cylindrical first shaft portion 95 extending from the first extension connecting portion 93, and a first extension contact portion 97 provided at the end of the first shaft portion 95 opposite to the first extension connecting portion 93. A through hole 95a is formed in the first shaft portion 95 at a position corresponding to a circumferential groove 117a (FIG. 10) described later. The first extension connecting portion 93 is formed to have a larger diameter than the first shaft portion 95, and can be fixed to the contact portion 91 by a bolt 94. The first extension contact portion 97 has an outer circumferential surface formed to have a larger diameter than the first shaft portion 95, and an inner circumferential surface formed to have the same diameter as the inner circumferential surface of the first shaft portion 95.

[0048] 12 is a perspective view of the second extension member 83. The second extension member 83 has a second extension connecting portion 111 connected to the first extension contact portion 97 shown in FIG. 10, a cylindrical second shaft portion 113 extending from the second extension connecting portion 111, and a second extension contact portion 115 provided on the end of the second shaft portion 113 opposite to the second extension connecting portion 111. The second extension connecting portion 111 and the second extension contact portion 115 have a larger diameter than the second shaft portion 113.

[0049] The second extension connecting portion 111 has an insertion shaft 117 extending toward the first extension contact portion 97 and the first shaft portion 95 of the first extension member 81 shown in Fig. 10. The insertion shaft 117 is inserted into the inner circumference of the first extension contact portion 97 and the first shaft portion 95. The outer diameter of this insertion shaft 117 is equal to or slightly smaller than the inner diameter of the first shaft portion 95 and the inner diameter of the inner peripheral surface of the first extension contact portion 97, and is sized to be freely inserted and removed from the first shaft portion 95 without rattling. The insertion shaft 117 may be formed integrally with the second extension connecting portion 111, or may be configured such that the two are formed separately and then joined.

[0050] A circumferential groove 117a is formed around the entire outer periphery of the insertion shaft 117. When the tip of the insertion shaft 117 is inserted into the first shaft portion 95 from the first extension contact portion 97 of the first extension member 81 and the second extension connecting portion 111 is abutted against the first extension contact portion 97, the axial positions of the through hole 95a and the circumferential groove 117a coincide. In this state, the tip of a fastening member 119 such as a thumbscrew is inserted from the through hole 95a into the circumferential groove 117a to fix the second extension member 83 to the first extension member 81, so that the second extension member 83 is prevented from coming off the first extension member 81.

[0051] 13 is an explanatory diagram showing, in partial cross section, a step-by-step procedure for attaching the second extension member 83 to the first extension member 81 fixed to the fixing mechanism 39B. The extension member is attached to ensure the extension length Le required to hold the workpiece W from the contact portion 91 of the fixing mechanism 39B to the position where the workpiece W is abutted. The longer the extension length Le, the heavier the extension member becomes, and the harder it is to handle. Therefore, from the viewpoint of workability, it is preferable to divide the extension member into a plurality of relatively short pieces and connect them together.

[0052] As in the configuration example described above, when attaching two extension members, the first extension member 81 and the second extension member 83, to the contact portion 91 of the fixing mechanism 39B, first, the first extension connecting portion 93 of the first extension member 81 is fixed to the contact portion 91 with a fixing bolt 94. Then, the insertion shaft 117 of the second extension member 83 is inserted along the inner circumferential surface of the first shaft portion 95 from the first extension contact portion 97 side of the fixed first extension member 81. The second extension member 83 is inserted until the second extension connecting portion 111 abuts against the first extension contact portion 97.

[0053] In this way, the weight of the second extension member 83 is supported by the first extension member 81, resulting in a temporary fixed state, and the workload of the worker who continues to hold the second extension member 83 can be reduced. In addition, the first extension member 81 and the second extension member 83 are positioned simply by inserting the second extension member 83 into the first extension member 81 until it butts against the first extension member 81, and in this positioned state, the second extension member 83 can be easily fixed to the first extension member 81 by the fastening member 119. Note that since the circumferential groove 117a is formed around the entire circumference of the insertion shaft 117, there is no need to be aware of the rotational position when inserting the second extension member 83, improving workability. In addition, the second extension member 83 can be fixed to the first extension member 81 by the simple task of screwing the fastening member 119.

[0054] In addition, in this configuration, the first extension member 81 and the second extension member 83 are used, but other extension members may be further combined as necessary. For example, other extension members may be further added in the same manner as the joining form of the first extension member 81 and the second extension member 83 described above. In that case, the types of workpieces that can be held can be further increased.

[0055] As described above, according to the workpiece holding device 100 having this configuration, the second extension member 83 can be joined to the first extension member 81 by a simple operation. This allows various types of workpieces, such as steel materials of various shapes such as H-shaped steel, aluminum materials, etc., to be more simply and accurately positioned and held in the annular holding portion 27. This allows the posture of the workpiece to be more accurately controlled, and the desired welding can be performed with high precision.

[0056] <Modification of extension member> 14 is a schematic cross-sectional view showing another joining form between the first extension member 81A and the second extension member 83A. In this modification, an insertion shaft 117 is provided in the first extension member 81A, and a through hole 113a is provided in the second extension member 83A. The insertion shaft 117 is inserted into the second shaft portion 113 of the second extension member 83A, and the fastening member 119 is fixed by protruding from the through hole 113a to the circumferential groove 117a. This also makes it possible to connect the first extension member 81A and the second extension member 83A by a simple operation.

[0057] The present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these are included in the scope of protection sought.

[0058] As described above, the present specification discloses the following: (1) A work holding device having a pair of rotation positioners that holds both ends of a long workpiece and rotates the workpiece to place the workpiece in an arbitrary position, The rotational positioner includes: An annular holding portion that is formed in an annular shape and holds the workpiece radially inward in a position in which the radial direction of the annular ring is oriented vertically; a support portion that supports the annular holding portion rotatably around an axial direction of the ring; Equipped with The annular holding portion is A pair of first fixing mechanisms are provided on the inner peripheral side of the annular ring, and advance and retreat in a first direction along a radial direction of the annular holding portion to clamp and fix the workpiece in the first direction; A pair of second fixing mechanisms each move forward and backward in a second direction perpendicular to the first direction and along a radial direction of the annular holding portion to clamp and fix the workpiece in the second direction; Equipped with One of the pair of first fixing mechanisms is a base fixing mechanism including a mounting table having a mounting surface on which the work is placed and which is movable in a radial direction of the annular holding portion, The mounting table has: A butting member extending upward from the mounting table and having a butting portion against which the workpiece butts; a fixing portion that positions the abutting member along the placement surface in a direction toward or away from the workpiece and fixes the abutting member to the placement table; It is provided with Work holding device. According to this workpiece holding device, when the workpiece is held by the annular holding portion, the workpiece can be accurately positioned in the second direction by placing the workpiece on the mounting table while contacting it with the abutment portion of the abutment member positioned by the fixed portion.

[0059] (2) The fixing portion includes a linear groove formed in the abutting member and parallel to the mounting surface, The workpiece holding device according to (1), wherein the groove has a pair of groove side walls that sandwich the end of the mounting table in the thickness direction of the mounting surface. According to this workpiece holding device, the abutment member is fixed to the mounting table with the groove side wall of the recessed groove in surface contact with the mounting table, so that even if a large impact is applied to the abutment member from the workpiece when the workpiece is brought into contact with the abutment member, the positional displacement of the abutment member due to the impact can be suppressed.

[0060] (3) The fixing portion is formed at an end portion of the mounting table on a side sandwiched in the concave groove, and includes a plurality of screw holes formed parallel to the mounting surface; a plurality of through holes formed at positions corresponding to the plurality of screw holes in a groove bottom of the recessed groove of the abutment member; Including, The workpiece holding device according to (2), wherein the abutment member is screwed into one of the screw holes through the through hole with the end of the mounting table clamped in the groove. According to this workpiece holding device, the position of the abutment member can be easily changed by screwing the abutment member into any one of the screw holes in the mounting table.

[0061] (4) The work holding device according to (3), wherein the through hole is a long hole that runs along the groove. According to this workpiece holding device, the position of the abutment member can be finely adjusted.

[0062] (5) A work holding device described in any one of (1) to (4), wherein the abutment member has an upright portion having the abutment portion and a bottom portion extending along the placement surface perpendicular to the upright portion. According to this workpiece holding device, by having a bottom portion extending perpendicular to the standing portion against which the workpiece abuts, the force that the standing portion receives from the workpiece can be easily received by the bottom portion.

[0063] (6) The workpiece holding device according to any one of (1) to (5), wherein the abutment portion extends to a height of 100 mm or more above the placement surface. According to this workpiece holding device, even when a small workpiece is held by the annular holding portion, the workpiece can be reliably brought into contact with the abutment portion before being placed on the placement table.

[0064] (7) The workpiece holding device according to any one of (1) to (6), further comprising a position measuring unit that measures a position of the abutment member relative to the mounting table. According to this workpiece holding device, the position measuring unit can position the abutment member with high accuracy.

[0065] (8) The work holding device described in (7), wherein the position measurement unit has a scale provided on either the abutment member or the mounting table, and an indicator provided on the other of the two, which indicates a position on the scale. According to this workpiece holding device, the relative position between the abutment member and the mounting table can be measured by the scale and the indicator.

[0066] (9) The pair of second fixing mechanisms include a nut portion fixed to each mounting base of the annular holding portion; A screw shaft that is engaged with the nut portion and can extend and retract toward the radially inner side of the annular holding portion; A contact portion provided at a radially inner tip of the screw shaft; A first extension member having a base end side detachably connected to the contact portion; A second extension member having a base end side detachably connected to a tip end of the first extension member opposite to the base end side; Equipped with The first extension member is A first extension connecting portion connected to the contact portion; A cylindrical first shaft portion extending from the first extension connecting portion; a first extended contact portion provided at an end portion of the first shaft portion opposite to the first extended connecting portion; having The second extension member is a second extension connecting portion connected to the first extension contact portion; A cylindrical second shaft portion extending from the second extension connecting portion; a second extended contact portion provided at an end portion of the second shaft portion opposite the second extended connecting portion; having One of the first extension member and the second extension member has an insertion axis extending toward the other one, The insertion shaft has a circumferential groove formed over the entire circumference of its outer circumferential surface, The other of the first extension member and the second extension member has a through hole formed at a position corresponding to the circumferential groove, a fastening member having a tip inserted from the through hole to the circumferential groove and configured to prevent the second extension member from coming off the first extension member; A work holding device according to any one of (1) to (8). According to this work holding device, the first extension member and the second extension member can be temporarily fixed by inserting the insertion shaft provided on either one of the first extension member or the second extension member into the other, and the weight of the second extension member is supported by the first extension member. Also, the first extension member and the second extension member can be easily fixed by inserting the fastening member into the circumferential groove from the through hole.

[0067] (10) A female thread is formed in the through hole, The workpiece holding device according to claim 9, wherein the fastening member has a male thread formed thereon that meshes with the female thread. According to this workpiece holding device, the fastening members can be easily fixed by screws.

[0068] (11) The work holding device according to any one of (1) to (10), wherein the work is an H-shaped steel. This workpiece holding device makes it possible to efficiently hold a workpiece while avoiding interference with the flanges formed on both ends of the web of the H-section steel.

[0069] (12) A method for holding a long workpiece by rotating the workpiece while holding both ends of the workpiece with a pair of rotary positioners, the method comprising the steps of: The rotational positioner includes: The workpiece is held radially inward in a position in which the radial direction of the ring is oriented vertically, and the workpiece is supported rotatably around the axial direction of the ring. The annular holding portion is A pair of first fixing mechanisms are provided on the inner peripheral side of the annular ring, and advance and retreat in a first direction along a radial direction of the annular holding portion to clamp and fix the workpiece in the first direction; A pair of second fixing mechanisms each move forward and backward in a second direction perpendicular to the first direction and along a radial direction of the annular holding portion to clamp and fix the workpiece in the second direction; Equipped with One of the pair of first fixing mechanisms is a base fixing mechanism including a mounting table having a mounting surface on which the workpiece is placed that is movable in a radial direction of the annular holding portion, A butting member having an butting portion that extends upward from the mounting table and butts against the work is positioned and fixed to the mounting table in a direction approaching or receding from the work along the mounting surface; When placing the workpiece on the placement table, the workpiece is lowered while being brought into contact with the abutment portion, and placed on the placement table. Workpiece holding method. According to this workpiece holding method, when the workpiece is held in the annular holding portion, the workpiece can be accurately positioned in the second direction by placing it on the mounting table while contacting it with the abutment portion of the abutment member positioned by the fixed portion.

[0070] (13) The pair of second fixing mechanisms include a pair of advance / retract shafts each having one end supported by a mounting base of each of the annular holding portions and each capable of extending and retracting radially inward of the annular holding portion; Among the contact portions provided at the other ends of the pair of the advance / retract shafts, a first extension member is detachably connected to one of the contact portions, and a second extension member is detachably connected to the other of the contact portions, The first extension member is A first extension connecting portion connected to the contact portion; A cylindrical first shaft portion extending from the first extension connecting portion; a first extended contact portion provided at an end portion of the first shaft portion opposite to the first extended connecting portion; having The second extension member is a second extension connecting portion connected to the first extension contact portion; a cylindrical second shaft portion extending from the second extension connecting portion; a second extended contact portion provided at an end portion of the second shaft portion opposite the second extended connecting portion; having The second extension member further includes an insertion shaft that is inserted into the first shaft portion of the second extension connecting portion, A circumferential groove is formed on the outer peripheral surface of the insertion shaft, The first shaft portion has a through hole formed at a position corresponding to the circumferential groove, a fastening member is inserted from the through hole to the circumferential groove to prevent the first extension member from coming off the second extension member; A workpiece holding method as described in (12). According to this workpiece holding method, the first extension member and the second extension member can be temporarily fixed by inserting an insertion shaft provided on either the first extension member or the second extension member into the other, and the weight of the second extension member is supported by the first extension member. Also, the first extension member and the second extension member can be easily fixed by inserting a fastening member into the circumferential groove from the through hole. [Explanation of symbols]

[0071] 25A, 25B Rotary Positioner 27 Annular retaining part 29 Support part 39A,39C Fixing mechanism (1st fixing mechanism) 39B, 39D Fixing mechanism (second fixing mechanism) 41 Placement table 41a Placement surface 43 Stopping member 43a Standing part 43b bottom 44 Stopping part 45 Fixed part 63 Groove 65 long hole 69 Screw hole 71 Scale 73 Indicator 75 Position measurement unit 81 1st extension member 83 Second extension member 85 Nut 87 Screw shaft 91 Contact part 93 1st extension connection part 95 First shaft 95a through hole 97 1st extension contact part 111 2nd extension connection 113 Second shaft 113a Through hole 115 2nd extension contact part 117 Insertion shaft 117a Circumferential groove 119 Fastening members 100 Work holding device D1 1st direction D2 2nd direction W,Wa Work

Claims

1. A work holding device having a pair of rotation positioners that holds both ends of a long workpiece and rotates the workpiece to place the workpiece in an arbitrary position, The rotational positioner includes: An annular holding portion that is formed in an annular shape and holds the workpiece radially inward in a position in which the radial direction of the annular ring is oriented vertically; a support portion that supports the annular holding portion rotatably around an axial direction of the ring; Equipped with The annular holding portion is A pair of first fixing mechanisms are provided on an inner peripheral side of the annular ring, and each of the first fixing mechanisms advances and retreats in a first direction along a radial direction of the annular holding portion to clamp and fix the workpiece in the first direction; a pair of second fixing mechanisms that advance and retreat in a second direction perpendicular to the first direction and along a radial direction of the annular holding portion to clamp and fix the workpiece in the second direction; Equipped with One of the pair of first fixing mechanisms is a base fixing mechanism including a mounting table having a mounting surface on which the work is placed and which is movable in a radial direction of the annular holding portion, The mounting table has: A butting member extending upward from the mounting table and having a butting portion against which the workpiece butts; a fixing portion that positions the abutting member along the placement surface in a direction toward or away from the workpiece and fixes the abutting member to the placement table; It is provided with Work holding device.

2. The fixing portion includes a linear groove formed in the abutting member and parallel to the placement surface, The recessed groove has a pair of groove side walls that sandwich the end of the mounting table in a thickness direction of the mounting surface. The workpiece holding device according to claim 1 .

3. The fixing portion is formed at an end portion of the mounting table on a side sandwiched in the concave groove, and includes a plurality of screw holes formed parallel to the mounting surface; a plurality of through holes formed at positions corresponding to the plurality of screw holes in a groove bottom of the recessed groove of the abutment member; Including, the abutment member is screwed into any one of the screw holes through the through hole in a state in which an end of the mounting table is sandwiched in the recessed groove, The workpiece holding device according to claim 2 .

4. The through hole is a long hole along the groove. The workpiece holding device according to claim 3.

5. The abutting member has an upright portion having the abutting portion, and a bottom portion extending along the placement surface perpendicular to the upright portion. The workpiece holding device according to claim 1 .

6. The abutment portion extends to a height of 100 mm or more above the placement surface. The workpiece holding device according to claim 1 .

7. a position measuring unit that measures a positioning position of the abutment member relative to the placement table, The workpiece holding device according to claim 1 .

8. the position measurement unit has a scale provided on either the abutting member or the mounting table, and an indicator provided on the other of them, for indicating a position on the scale. The workpiece holding device according to claim 7.

9. The pair of second fixing mechanisms include A nut portion fixed to each mounting base of the annular holding portion; A screw shaft that is engaged with the nut portion and can extend and retract toward the radially inner side of the annular holding portion; A contact portion provided at a radially inner tip of the screw shaft; A first extension member having a base end side detachably connected to the contact portion; A second extension member having a base end side detachably connected to a tip end of the first extension member opposite to the base end side; Equipped with The first extension member is A first extension connecting portion connected to the contact portion; a cylindrical first shaft portion extending from the first extension connecting portion; a first extended contact portion provided at an end portion of the first shaft portion opposite to the first extended connecting portion; having The second extension member is a second extension connecting portion connected to the first extension contact portion; a cylindrical second shaft portion extending from the second extension connecting portion; a second extended contact portion provided at an end portion of the second shaft portion opposite to the second extended connecting portion; having One of the first extension member and the second extension member has an insertion axis extending toward the other one, The insertion shaft has a circumferential groove formed over the entire circumference of its outer circumferential surface, The other of the first extension member and the second extension member has a through hole formed at a position corresponding to the circumferential groove, a fastening member having a tip inserted from the through hole to the circumferential groove and configured to prevent the second extension member from coming off the first extension member; The workpiece holding device according to claim 1 .

10. The through hole is formed with a female screw, The fastening member is formed with a male thread that meshes with the female thread. It is being The workpiece holding device according to claim 9.

11. The workpiece is an H-shaped steel. The workpiece holding device according to any one of claims 1 to 10.

12. A workpiece holding method in which a pair of rotary positioners is used to hold both ends of a long workpiece and rotate the workpiece to place the workpiece in an arbitrary position, The rotational positioner includes: The workpiece is held radially inward in a position in which the radial direction of the ring is oriented vertically, and the workpiece is supported rotatably around the axial direction of the ring. The annular holding portion is A pair of first fixing mechanisms are provided on an inner peripheral side of the annular ring, and each of the first fixing mechanisms advances and retreats in a first direction along a radial direction of the annular holding portion to clamp and fix the workpiece in the first direction; a pair of second fixing mechanisms that advance and retreat in a second direction perpendicular to the first direction and along a radial direction of the annular holding portion to clamp and fix the workpiece in the second direction; Equipped with One of the pair of first fixing mechanisms is a base fixing mechanism including a mounting table having a mounting surface on which the workpiece is placed that is movable in a radial direction of the annular holding portion, A butting member having an butting portion that extends upward from the mounting table and butts against the work is positioned and fixed to the mounting table in a direction approaching or receding from the work along the mounting surface; When placing the workpiece on the placement table, the workpiece is lowered while being brought into contact with the abutment portion, and placed on the placement table. Workpiece holding method.

13. The pair of second fixing mechanisms include a pair of reciprocating shafts, one end of which is supported by each of the mounting bases of the annular holding portions and each of which is capable of extending and retracting radially inward of the annular holding portion; a first extension member detachably connected to one of the contact portions provided at the other end of each of the pair of advance / retract shafts, and a second extension member detachably connected to the other of the contact portions, The first extension member is A first extension connecting portion connected to the contact portion; a cylindrical first shaft portion extending from the first extension connecting portion; a first extended contact portion provided at an end portion of the first shaft portion opposite to the first extended connecting portion; having The second extension member is a second extension connecting portion connected to the first extension contact portion; a cylindrical second shaft portion extending from the second extension connecting portion; a second extended contact portion provided at an end portion of the second shaft portion opposite to the second extended connecting portion; having The second extension member further includes an insertion shaft that is inserted into the first shaft portion and into the second extension connecting portion. A circumferential groove is formed on the outer peripheral surface of the insertion shaft, a through hole is formed in the first shaft portion at a position corresponding to the circumferential groove; a fastening member is inserted from the through hole to the circumferential groove to prevent the first extension member from coming off the second extension member; The workpiece holding method according to claim 12.

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