GANTRY LOADER, MACHINE TOOL EQUIPPED WITH SAME, AND WORK PROCESSING METHOD

Abstract

To use three handle chucks in simple structure which eliminate the need for centering to efficiently attach and detach a plurality of workpieces by simple facilities.SOLUTION: A gantry loader is configured to: grip an unprocessed work with two of three hand chucks 31, 32 and 33 by moving the three hand chucks by an elevation member 24 to a workpiece stocker 40; move to one of a plurality of workpiece chucks 9 by the elevation member 24 with two unprocessed workpieces gripped; detach a processed workpiece from the workpiece chuck 9; rotate a rotary table 30 in a circumferential direction to attach the unprocessed workpiece to the workpiece chuck 9; move the rotary table 30 by the elevation member 24 to another workpiece chuck 9; after detaching the processed work with the hand chuck, rotate the rotary table 30 at a predetermined angle to attach another unprocessed work to the workpiece chuck 9; and then process the unprocessed work fixed to the plurality of workpiece chucks 9.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gantry loader, a machine tool equipped with the same, and a method for machining a workpiece. [Background technology]

[0002] 2. Description of the Related Art Conventionally, as disclosed in, for example, Patent Document 1, a multi-axis machine or a combined machining tool that simultaneously machines a plurality of workpieces is known.

[0003] Also, a loading device including a rail section and a loader that travels along the rail section is known, as in Patent Document 2. In this loading device, the loader has a rotating section and an arm section that extends and retracts from the rotating section, and the arm section has a plurality of hand sections that hold workpieces. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3833386 [Patent Document 2] JP 2020-78847 A Summary of the Invention [Problem to be solved by the invention]

[0005] When replacing workpieces attached to parallel-arranged spindles or fixtures as in Patent Document 1, two hands for machined workpieces and two hands for unmachined workpieces are installed and the workpieces are replaced simultaneously.

[0006] Even with two hand units as in Patent Document 2, multiple arm units are still required.

[0007] In such a case, four or more chucks would be required, which would not only be expensive but would also make it difficult to center the workpiece and the chuck, hindering productivity improvements.

[0008] The present invention has been made in consideration of these points, and its object is to enable efficient attachment and detachment of multiple workpieces with simple equipment using three hand chucks that have a simple structure and do not require centering. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention uses a rotary table having three rotatable hand chucks.

[0010] Specifically, the first invention is directed to a gantry loader that exchanges multiple workpieces of a machine tool, The gantry loader is Three hand chucks that can attach and detach the above workpieces, a rotary table having the three hand chucks spaced at predetermined intervals in a circumferential direction and rotating the hand chucks at a predetermined angle; and a loader for moving the rotary table to a predetermined position.

[0011] According to the above configuration, the three hand chucks can be indexed to the same position by rotating them in the circumferential direction, so as long as they are positioned by the loader, there is no need to perform new centering when changing the hand chuck. Also, when replacing two workpieces at the same time, three hand chucks are sufficient, making the configuration and control easier.

[0012] In the second invention, in the first invention, The rotary table has a rectangular prism-shaped table body, and the hand chucks are provided on three of four circumferentially consecutive faces of the table body.

[0013] According to the above configuration, since the loader can be easily indexed between -90°, 0°, and +90° with a simple structure, it is possible to obtain a loader that is inexpensive and easy to control.

[0014] In a third aspect of the present invention, in the first or second aspect of the present invention, The rotary table has a triangular prism-shaped table body, and the hand chuck is provided on each of three consecutive faces in the circumferential direction of the table body.

[0015] According to the above configuration, since the loader can be easily indexed between -120°, 0°, and +120° with a simple structure, it is possible to obtain a loader that is inexpensive and easy to control.

[0016] In a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, The hand chuck has a step in the jaw portion so that it can grip both a workpiece with a large outer diameter and a workpiece with a small outer diameter.

[0017] According to the above configuration, a workpiece with a small outer diameter can be gripped by the part of the jaw with a small inner diameter, and a workpiece with a large outer diameter can be gripped by the part of the jaw with a large inner diameter, so that even workpieces with different outer diameters can be efficiently attached and detached on a single rotary table.

[0018] The machine tool of the fifth invention comprises: A gantry loader according to any one of the first to fourth aspects of the present invention; a work stocker on which unmachined and machined workpieces are placed; A plurality of work chucks to which the work is fixed; A plurality of processing units for processing the workpiece fixed to the workpiece chuck; and a control unit that controls the rotary table to move to one of the work chucks, remove the machined workpiece with the hand chuck, then rotate the rotary table a predetermined angle to attach an unmachined workpiece to the work chuck, move the rotary table relatively to another of the work chucks, remove the machined workpiece with the hand chuck, and then rotate the rotary table a predetermined angle to attach an unmachined workpiece to the work chuck.

[0019] According to the above configuration, a highly marketable machine tool capable of efficiently exchanging two workpieces can be obtained with a simple configuration of three hand chucks. Note that "moving the rotary table relatively to another one of the workpiece chucks" means that either the rotary table or the workpiece chuck can be moved.

[0020] In the sixth aspect of the present invention, a method for machining a workpiece includes: preparing three hand chucks for mounting and dismounting a workpiece, a rotary table having the three hand chucks spaced at predetermined intervals in a circumferential direction and rotating the hand chucks at a predetermined angle, and a loader for moving the rotary table to a predetermined position; The loader moves the three hand chucks to the work stocker, and the unmachined work is gripped by two of the three hand chucks. With the two unmachined workpieces held in place, the loader moves to one of the multiple workpiece chucks, removing a machined workpiece from one of said workpiece chucks by said free hand chuck; The rotary table is rotated in a circumferential direction to attach the unmachined workpiece to the workpiece chuck; The rotary table is moved relatively to another of the work chucks, and the machined workpiece is removed by the vacant hand chuck. Then, the rotary table is rotated by a predetermined angle to mount another unmachined workpiece on the work chuck. machining the unmachined workpieces fixed to the plurality of work chucks; The loader is moved to the work stocker, and the two machined workpieces are placed on the work stocker.

[0021] According to the above configuration, the three hand chucks can be indexed to the same position by rotating them in the circumferential direction, so as long as they are positioned by the loader, there is no need to re-center the hand chucks when changing them, making control easy. Also, when replacing two workpieces at the same time, three hand chucks are sufficient, making control easy. Note that "moving the rotary table relatively to another workpiece chuck" means that either the rotary table or the workpiece chuck can be moved.

[0022] In a seventh aspect of the present invention, in the sixth aspect of the present invention, The rotary table is rotated by 90° to load and unload the workpiece.

[0023] According to the above configuration, since the indexing is performed between -90°, 0°, and +90°, the indexing can be easily performed with a simple structure, and the control is extremely easy.

[0024] In an eighth aspect of the present invention, in the sixth aspect of the present invention, The rotary table is rotated by 120° to load and unload the workpiece.

[0025] According to the above configuration, indexing between -120°, 0°, and +120° can be performed easily with a simple structure, and control is extremely easy. Effect of the Invention

[0026] As described above, according to the present invention, the three hand chucks have a simple structure and do not require centering, making it possible to efficiently mount and remove multiple workpieces with simple equipment. [Brief description of the drawings]

[0027] [Figure 1] 1 is a perspective view showing a machine tool including a gantry loader according to a first embodiment of the present invention. [Diagram 2]Regarding the first embodiment of the present invention, (a) is an oblique view showing how a machined workpiece is unloaded from a first work chuck, (b) is an oblique view showing how the rotary table is rotated to determine the loading position of an unmachined workpiece, and (c) is an oblique view showing how an unmachined workpiece is attached to the first work chuck. [Diagram 3] Regarding the first embodiment of the present invention, (a) is an oblique view showing how the machine moves in front of the second work chuck to determine the unloading position of the second machined work, (b) is an oblique view showing how the second machined work is unloaded from the second work chuck, and (c) is an oblique view showing how the rotary table is rotated to determine the loading position of the second unmachined work. [Figure 4] Regarding the first embodiment of the present invention, (a) is an oblique view showing the state where a second unmachined workpiece is loaded onto the second work chuck, and (b) is an oblique view showing the state where the two work chucks are released and machining of the two unmachined workpieces begins. [Diagram 5] Regarding the first embodiment of the present invention, (a) is an oblique view showing how the machine moves up to above the work stocker and determines the discharge position, (b) is an oblique view showing how the second machined workpiece has been discharged to the work stocker, and (c) is an oblique view showing how the machine moves up to above the third unmachined workpiece and determines its clamp position. [Figure 6] Regarding embodiment 1 of the present invention, (a) is an oblique view showing how the third unmachined workpiece is clamped, (b) is an oblique view showing how the ejection position of the first machined workpiece is determined, and (c) is an oblique view showing how after the first machined workpiece is ejected, it moves to the position of the fourth unmachined workpiece. [Figure 7] FIG. 1A is a perspective view showing how the rotary table is rotated to determine the clamping position of the fourth unmachined workpiece according to the first embodiment of the present invention, and FIG. 1B is a perspective view showing how the fourth unmachined workpiece has been clamped. [Figure 8]Regarding the second embodiment of the present invention, (a) is an oblique view showing how the rotary table moves up to the front of the first work chuck to determine the unloading position, (b) is an oblique view showing how the first machined workpiece is unloaded from the first work chuck, and (c) is an oblique view showing how the rotary table is rotated to determine the loading position of the first unmachined workpiece relative to the first work chuck. [Figure 9] Regarding the second embodiment of the present invention, (a) is an oblique view showing the first unmachined workpiece being loaded onto the first work chuck, (b) is an oblique view showing the second work chuck moving in front of the second work chuck to determine the unloading position for the second machined workpiece, and (c) is an oblique view showing the unloading of the second machined workpiece. [Figure 10] Regarding embodiment 2 of the present invention, (a) is an oblique view showing how the loading position of the second unmachined workpiece is determined for the second workpiece chuck, (b) is an oblique view showing how the second unmachined workpiece has been loaded, and (c) is an oblique view showing how the two workpieces are released from the two workpiece chucks and machining of the two unmachined workpieces begins. [Figure 11] Regarding the second embodiment of the present invention, (a) is an oblique view showing how the rotary table is moved up to above the work stocker and rotated 30° to determine the discharge position, (b) is an oblique view showing how the second machined workpiece is discharged to the work stocker, and (c) is an oblique view showing how the rotary table is moved up to above the third unmachined workpiece and how its clamp position is determined. [Figure 12] Regarding the second embodiment of the present invention, (a) is an oblique view showing how the third unmachined workpiece is clamped, (b) is an oblique view showing how the rotary table is rotated 120 degrees to determine the discharge position of the first machined workpiece, and (c) is an oblique view showing how the first machined workpiece is discharged. [Figure 13]FIG. 11A is a perspective view showing the state of moving to the fourth unmachined workpiece and determining its clamping position, and FIG. 11B is a perspective view showing the state of clamping the fourth unmachined workpiece, relating to the second embodiment of the present invention. [Figure 14] 10A shows a rotary table and a work chuck according to another embodiment, in which FIG. 10A shows how the unloading position of the smaller workpiece is determined, and FIG. 10B is an enlarged perspective view of the rotary table and its surroundings in a state in which a small unmachined workpiece and a large unmachined workpiece are clamped at their corresponding clamping positions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0029] (Embodiment 1) FIG 1 shows a machine tool 1 including a gantry loader 20 according to a first embodiment of the present invention. This machine tool 1 is, for example, a grinding machine, and is equipped with a bed 2 to be placed on a mounting surface in a factory or the like. The machine tool 1 may be another machining machine such as a lathe. The machine tool 1 is equipped with a controller 41 as a control unit that controls the entire machine tool 1. This controller 41 is, for example, composed of a microcomputer.

[0030] The bed 2 is provided with two X-axis tables 3 that are movable in the X-axis direction, and each X-axis table 3 is equipped with a Z-axis table 4 that is movable in the Z-axis direction. Each Z-axis table 4 is provided with a spindle 5 as a processing unit that can rotate with a tool 5a attached. In this embodiment, two spindles 5 are provided. Two or more spindles 5 may be provided in the machine tool 1. Although not described in detail, the tool 5a can be automatically replaced from a tool stocker under the control of the controller 41.

[0031] A Y-axis table 7 that is movable in the Y-axis direction is mounted on a pair of columns 6 extending vertically from the bed 2, and a main shaft (C-axis 8) is provided on each Y-axis table 7. A work chuck 9 is rotatably provided on this C-axis 8. Although not shown, actuators that move each table 3, 4, 7 are not particularly limited and may be constituted, for example, by an air cylinder, an electric motor, a hydraulic cylinder, or the like.

[0032] The machine tool 1 is provided above the bed 2 with a gantry loader 20 for exchanging a plurality of workpieces.

[0033] The gantry loader 20 includes, for example, four vertical support columns 21 and two horizontal traveling rails 22, and one horizontal rail 23 is provided for horizontal movement on these two traveling rails 22. A lifting member 24 is provided on this horizontal rail 23 so as to be movable up and down. Although not shown, the actuator for moving the horizontal rail 23 and the lifting member 24 is not particularly limited and may be, for example, an air cylinder, an electric motor, or a hydraulic cylinder. With this configuration, the lifting member 24 can move within a predetermined range on the bed 2. The loader is made up of these support columns 21, traveling rails 22, horizontal rails, lifting members, and actuators for driving them.

[0034] The lifting member 24 is provided with a rotatable rotary table 30. Although not shown, the rotary table 30 is adapted to be rotated by a motor such as a servo motor, the rotation angle of which can be easily controlled.

[0035] As shown in an enlarged view in FIG. 2, the rotary table 30 has a rectangular prism-shaped (rectangular parallelepiped) table body 30a, and hand chucks 31, 32, and 33 are provided at predetermined intervals in the circumferential direction on three of four consecutive faces of the table body 30a. The hand chucks 31, 32, and 33 have, for example, openable and closable claw members, and are capable of attaching and detaching a workpiece of a predetermined size. The three hand chucks 31, 32, and 33 may be configured to be rotatable so that the posture of the workpiece can be changed. The rotary table 30 is configured to rotate the hand chucks 31, 32, and 33 by a predetermined angle under the control of a controller 41.

[0036] A work stocker 40 on which unmachined and machined workpieces are placed is provided on the side of the bed 2. The work stocker 40 may be in the form of a conveyor through which the workpieces are carried in and out.

[0037] Although details will be described later, in this embodiment, the controller 41 is configured to control the following: move the rotary table 30 to one of the work chucks 9, remove the machined workpiece with the hand chucks 31, 32, and 33, then rotate the rotary table 30 a predetermined angle to attach an unmachined workpiece to the work chuck 9, move the rotary table 30 relatively to another one of the work chucks 9, remove the machined workpiece with the hand chucks 31, 32, and 33, and then rotate the rotary table 30 a predetermined angle to attach an unmachined workpiece to the work chuck 9.

[0038] - Gantry loader operation - Next, an operation of the gantry loader 20 according to this embodiment will be described. Hereinafter, the controller 41 controls the operation of the entire machine tool 1 in accordance with a preset program.

[0039] First, as shown in FIG. 1, unmachined workpieces WB1, WB2, . . . are arranged on the work stocker 40.

[0040] Next, the first and second unmachined workpieces WB1, WB2 are chucked by the hand chucks 32, 33.

[0041] Next, in this state, the rotary table 30 is moved to the position of the first work chuck 9 using the traveling rail 22 and the horizontal rail 23, and the first machined workpiece WA1 is indexed.

[0042] Next, as shown in FIG. 2(a), the machined workpiece WA1 is unloaded from the first workpiece chuck 9.

[0043] Next, as shown in FIG. 2(b), the rotary table 30 is rotated by 90 degrees to determine the loading position of the unmachined workpiece WB1.

[0044] Next, as shown in FIG. 2(c), a first unmachined workpiece WB1 is attached to a first workpiece chuck 9.

[0045] Next, as shown in FIG. 3(a), the horizontal rail 23 is used to move the rotary table 30 to a position in front of the second work chuck 9, thereby determining the unloading position of the second machined work WA2.

[0046] Next, as shown in FIG. 3(b), the second machined workpiece WA2 is unloaded from the second workpiece chuck 9.

[0047] Next, as shown in FIG. 3(c), the rotary table 30 is rotated by 90 degrees to determine the loading position of the second unmachined workpiece WB2.

[0048] Next, as shown in FIG. 4(a), a second unmachined workpiece WB2 is loaded onto a second workpiece chuck 9.

[0049] Next, as shown in FIG. 4(b), the rotary table 30 moves away from the two work chucks 9, and starts machining the two unmachined workpieces WB1 and WB2.

[0050] Then, while the unmachined workpiece is being machined, the lifting member 24 moves to above the workpiece stocker 40 to determine the discharge position, as shown in Fig. 5(a). In this embodiment, hand chucks are provided at 90° intervals on the outer periphery of the rotary table 30, which is advantageous in that it is not necessary to rotate the rotary table 30 from the position in which the second unmachined workpiece WB2 is loaded.

[0051] Next, as shown in FIG. 5(b), the lifting member 24 is lifted and lowered to discharge the second machined workpiece WA2 into the workpiece stocker 40.

[0052] Next, as shown in FIG. 5(c), the lifting member 24 is moved horizontally to above the third unmachined workpiece WB3, and its clamp position is determined.

[0053] Next, as shown in FIG. 6(a), the lifting member 24 is lifted and lowered to clamp the third unmachined workpiece WB3.

[0054] Next, as shown in FIG. 6(b), the rotary table 30 is rotated by 90 degrees to determine the discharge position of the first machined workpiece WA1.

[0055] Next, as shown in FIG. 6(c), after the first machined workpiece WA1 is discharged, the lifting member 24 is moved horizontally to the position of the fourth unmachined workpiece WB4.

[0056] Next, as shown in FIG. 7(a), the rotary table 30 is rotated 180° above the fourth unmachined workpiece WB4 to determine its clamp position.

[0057] Next, as shown in FIG. 7(b), the lifting member 24 is lifted and lowered to clamp the fourth unmachined workpiece WB4.

[0058] Then, return to the state shown in FIG. 1 and repeat the same process.

[0059] In this manner, the three hand chucks 31, 32, 33 are moved to the work stocker 40 by the lifting member 24, the unmachined workpiece is gripped by two of the three hand chucks 31, 32, 33, and in a state in which the two unmachined workpieces WB1, WB2 are gripped, the lifting member 24 is moved to one of the two work chucks 9, the machined workpiece WA1 is removed from one of the work chucks 9 by the vacant hand chuck 31, and the rotary table 30 is rotated in the circumferential direction to remove the unmachined workpiece WB1. After it is attached to a work chuck 9, the rotary table 30 is moved to another work chuck 9 by the lifting member 24, the machined work WA2 is removed by the free hand chuck 32, the rotary table 30 is rotated 90° and another unmachined work WB2 is attached to the work chuck 9, the unmachined workpieces fixed to the multiple work chucks 9 are machined, and it is moved to a work stocker 40 by the lifting member 24, and the two machined workpieces WA1, WA2 are placed on the work stocker 40, respectively.

[0060] In this embodiment, the rotary table 30 is rotated in 90° increments to load and unload the workpiece. Since the table can be indexed to -90°, 0°, and +90°, the lifting member 24 can be easily indexed with a simple structure, and is inexpensive and easy to control.

[0061] As described above, according to the present invention, the three hand chucks have a simple structure and do not require centering, making it possible to efficiently mount and remove multiple workpieces using simple equipment. FIG.

[0062] In this embodiment, the three hand chucks 31, 32, and 33 can be indexed to the same position by rotating them in the circumferential direction, so there is no need to perform new centering when changing the hand chucks as long as they are positioned by the lifting member 24. When replacing two workpieces at the same time, three hand chucks are sufficient, making the configuration and control easier.

[0063] Therefore, according to the gantry loader 20 of this embodiment, the three hand chucks 31, 32, and 33 have a simple structure and do not require centering, so that multiple workpieces can be efficiently attached and detached with simple equipment.

[0064] (Embodiment 2) 8 to 13 show a second embodiment of the present invention, which differs from the first embodiment in the shape of the rotary table 130. In the following embodiments, the same parts as those in Figs. 1 to 7 are given the same reference numerals and detailed description thereof will be omitted.

[0065] The rotary table 130 of this embodiment has a triangular prism-shaped table body 130a, and hand chucks 31, 32, and 33 are provided on three consecutive circumferential faces of the table body 130a. In this embodiment, the rotary table 30 is rotated by 120° to load and unload a workpiece.

[0066] In this embodiment, the X-axis table 3 and the Z-axis table 4 are provided on the C-axis 8 side where the work chuck 9 is located, rather than on the spindle 5 side. Although not shown, the spindle 5 side is provided on the Y-axis table 6.

[0067] Next, the operation of the gantry loader 20 according to this embodiment will be described.

[0068] As in the first embodiment, as shown in FIG. 8(a), the lifting member 24 uses the traveling rail 21 and the horizontal rail 23 to move to just before the first work chuck 9 and determine the unloading position.

[0069] Next, as shown in FIG. 8(b), the lifting member 24 or the Z-axis table 4 is moved to unload the first machined workpiece WA1 from the first workpiece chuck 9.

[0070] Next, as shown in FIG. 8(c), the rotary table 130 is rotated 120 degrees to determine the loading position of the first unmachined workpiece WB1 relative to the first workpiece chuck 9.

[0071] Next, as shown in FIG. 9(a), the lifting member 24 or the Z-axis table 4 is moved to load the first unmachined workpiece WB1 onto the first workpiece chuck 9.

[0072] Next, as shown in FIG. 9(b), the X-axis table 3 is moved to move the rotary table 130 to a position in front of the second work chuck 9, and the unloading position of the second machined work WA2 is determined.

[0073] Next, as shown in FIG. 9(c), the lifting member 24 or the Z-axis table 4 is moved to unload the second machined workpiece WA2.

[0074] Next, as shown in FIG. 10(a), the rotary table 30 is rotated by 120 degrees to determine the unloading position of the second unmachined workpiece WB2 relative to the second workpiece chuck 9.

[0075] Next, as shown in FIG. 10(b), the lifting member 24 or the Z-axis table 4 is moved to unload the second unmachined workpiece WB2.

[0076] Next, as shown in FIG. 10(c), the lifting member 24 moves away from the two work chucks 9, and machining of the two unmachined workpieces WB1 and WB2 begins.

[0077] 11(a), the lifting member 24 moves to above the work stocker 40 and determines the discharge position of the second machined workpiece WA2. Unlike the first embodiment, the hand chucks are provided in 120° increments, so the workpiece cannot be discharged in the current position. However, the second machined workpiece WA2 can be brought directly below by simply returning the angle by 30°, making control easy.

[0078] Next, as shown in FIG. 11(b), the lifting member 24 moves up and down to discharge the second machined workpiece WA2 into the workpiece stocker 40.

[0079] Next, as shown in FIG. 11(c), the lifting member 24 moves to above the third unmachined workpiece WB3 and determines its clamp position.

[0080] Next, as shown in FIG. 12(a), the lifting member 24 moves up and down to clamp the third unmachined workpiece WB3.

[0081] Next, as shown in FIG. 12(b), the rotary table 130 is rotated 120 degrees to determine the discharge position of the first machined workpiece WA1.

[0082] Next, as shown in FIG. 12(c), the lifting member 24 is moved up and down to discharge the first machined workpiece WA1.

[0083] Next, as shown in FIG. 13(a), the lifting member 24 moves to above the fourth unmachined workpiece WB4 and determines its clamp position.

[0084] Next, as shown in FIG. 13(b), the lifting member 24 is lifted and lowered to clamp the fourth unmachined workpiece WB4.

[0085] After this, the state returns to that shown in FIG. 1, and the same process is repeated.

[0086] In this embodiment, since the indexing is performed between -120°, 0°, and +120°, it is possible to obtain a lifting member 24 that is simple in structure and can be easily indexed, and is inexpensive and easy to control. Since there is no surface without a hand chuck as in the above-mentioned embodiment 1, there is no waste in the rotation of the rotary table 130 itself.

[0087] Therefore, the gantry loader 20 according to this embodiment also has three hand chucks that are of a simple structure and do not require centering, making it possible to efficiently load and unload multiple workpieces with simple equipment.

[0088] (Other embodiments) The present invention may have the following embodiments.

[0089] For example, as shown in Fig. 14, the two workpieces to be handled may be of different sizes. In this case, it is preferable that the hand chucks 31', 32', and 33' have unequal gripping portions, a portion X with a small inner diameter for gripping an unmachined workpiece WB1' with a small outer diameter, and a portion Y with a large inner diameter for gripping an unmachined workpiece WB2' with a large outer diameter. In this way, even two workpieces of different sizes can be easily handled by the hand chucks 31', 32', and 33' provided on one rotary table 30.

[0090] In the above embodiment, a microcomputer has been described as an example of the control unit (controller 41). However, the control unit may be configured in any physical manner as long as it controls the machine tool 1. For example, the control unit may utilize software (programs) such as a microcomputer or a programmable logic controller (PLC). Alternatively, the control unit may be realized by combining hardware (circuit components).

[0091] It should be noted that the above-described embodiments are essentially preferred examples, and are not intended to limit the scope of the present invention, its applications, or uses. [Explanation of symbols]

[0092] 1 Machine tools 2 beds 3 X-axis table 4 Z-axis table 5 Spindle (processing part) 5a Tools 5b Tool Stocker 6 Column 7 Y-axis table 8 C-axis 9 Work chuck 20 Gantry Loader 21 Support column (loader) 22 Running rail (loader) 23 Horizontal rail (loader) 24 Lifting member (loader) 30 Rotary Table 30a Table body 31 Hand chuck 31, 32, 33 Hand chuck 40 Work Stocker 41 Controller (control unit) 130 Rotary Table 130a Table body WA1, WA2 Machined workpiece WB1, WB2 Unmachined workpiece

Claims

1. A gantry loader for exchanging a plurality of workpieces of a machine tool, Three hand chucks that can attach and detach the above workpieces, a rotary table having the three hand chucks spaced at predetermined intervals in a circumferential direction and rotating the hand chucks at a predetermined angle; and a loader that moves the rotary table to a predetermined position. The rotary table has a triangular prism-shaped table body, and the hand chuck is provided on each of three consecutive circumferential faces of the table body. A gantry loader comprising:

2. A gantry loader according to claim 1; a work stocker on which unmachined and machined workpieces are placed; A plurality of work chucks to which the work is fixed; A plurality of processing units for processing the workpiece fixed to the workpiece chuck; and a control unit that controls the rotary table to move to one of the work chucks, remove the machined workpiece with the hand chuck, rotate the rotary table by a predetermined angle, and attach an unmachined workpiece to the work chuck, move the rotary table relatively to another one of the work chucks, remove the machined workpiece with the hand chuck, and then rotate the rotary table by a predetermined angle to attach an unmachined workpiece to the work chuck. A machine tool characterized by:

3. Providing a gantry loader as described in claim 1, The loader moves the three hand chucks to the work stocker, and the unmachined work is gripped by two of the three hand chucks. While holding the two unmachined workpieces, the loader moves to one of a plurality of work chucks; removing a machined workpiece from one of the work chucks by the free hand chuck; The rotary table is rotated in a circumferential direction to attach the unmachined workpiece to the workpiece chuck; The rotary table is moved relatively to another of the work chucks, and the machined workpiece is removed by the vacant hand chuck. Then, the rotary table is rotated by a predetermined angle to mount another unmachined workpiece on the work chuck. machining the unmachined workpieces fixed to the plurality of work chucks; The loader is moved to the work stocker, and the two machined workpieces are placed on the work stocker. A method for machining a workpiece, comprising:

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