Transfer mechanism and transfer device

Abstract

Transfer mechanism and transfer device. It includes: a track; first and second worktables movably arranged on the track; first and second arms, the bases of which are supported by the first and second worktables to be rotatable; and first and second drive mechanisms to move the first and second worktables independently along the track respectively. It is configured that the first and second arms are rotatably connected to each other at a position between the front end side and the base side of each, and the part closer to the front end side than the connection part of the first and second arms is a holding part for holding a workpiece. The movement of the first and second worktables driven by the first and second drive mechanisms in opposite directions relative to each other causes the first and second arms to perform clamping / loosening actions, and the coordinated movement in the same direction causes forward / return actions.

Description

Technical Field

[0001] The present invention relates to a transfer mechanism and a transfer device used in a press device. More specifically, it relates to a transfer mechanism and a transfer device for supplying workpieces to a die, conveying workpieces between dies, and taking out the formed workpieces. Background Art

[0002] As a material (workpiece) transfer device for a press device, there is a three-dimensional transfer device. In an existing three-dimensional transfer press, the workpieces in each forming process of a multi-process worktable are conveyed to the next worktable together by the clamping (holding of the workpiece), upward (rising), forward (advancing), downward (descending), releasing (release of the workpiece holding), and returning (retreating) actions of two feed rods. In addition, stamping is performed during the return action (refer to Patent Document 1).

[0003] In Patent Document 1, a ball screw nut mechanism is used as a mechanism for converting the rotation of a servo motor into a reciprocating linear motion of a feed carriage or the like. On the other hand, a transfer device of a type in which a linear motor is interposed in a linear motion portion has also been developed (refer to Patent Document 2). In this device, a feed carriage is provided on the upper parts of a pair of left and right rods fixed to a press device, and the feed carriage is reciprocally driven by a linear motor interposed between the feed carriage and the rods.

[0004] As transfer devices, in addition to the above-mentioned three-dimensional transfer device, a two-dimensional transfer device that does not move upward or downward is known. In addition, in addition to a transfer device having two feed rods, a single-rod type transfer device in which a holding portion for clamping a workpiece by the force of a spring or air drive is disposed on one feed rod is also known (refer to Patent Documents 3 and 4).

[0005] [Prior Art Documents]

[0006] [Patent Documents]

[0007] Patent Document 1: Japanese Utility Model Laid-Open No. 5-9726

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2005-144555

[0009] Patent Document 3: Japanese Utility Model Laid-Open No. 61-9145

[0010] Patent Document 4: Japanese Patent Application Laid-Open No. 2-142629

[0011] In the transfer device of Patent Document 1, in addition to two feed rods, it is also necessary to transfer the holding parts mounted on these feed rods and the workpieces on all the worktables. In addition, the feed rods with large inertia (intertia: inertia or inertial force) are accelerated and decelerated at high speed and then moved up and down. Therefore, a high-output servo motor is required. On the other hand, in the device of Patent Document 2, the entire feed rod is not driven, but the feed carriage movably provided on the fixed rod is reciprocated by a linear motor. Therefore, the motor output can be reduced. However, clamping and releasing are driven by the linear motor provided on the feed carriage, and moving up and down is driven by the linear motor provided on the clamping carriage. Therefore, this device also needs to drive a relatively large inertia and cannot dispense with a high-output motor.

[0012] In the transfer devices of Patent Documents 3 and 4, since the clamping action is performed by springs and cylinders, a motor is not required. However, since the entire feed rod is moved forward and backward, a high-output motor is required for driving the feed rod. Summary of the Invention

[0013] An object of the present invention is to provide a transfer mechanism and a transfer device that can be driven by a low-output motor and can reduce the number of motors.

[0014] The transfer mechanism 10 of the present invention is characterized by comprising: a rail 11; a first worktable 12 and a second worktable 13 movably provided on the rail 11; a first arm 18 and a second arm 19, the bases 25 of which are rotatably supported by the first worktable 12 and the second worktable 13; and a first drive mechanism 15 and a second drive mechanism 16 that independently move the first worktable 12 and the second worktable 13 along the rail 11, the transfer mechanism being configured such that the first arm 18 and the second arm 19 are rotatably connected to each other at a portion 17 between the front end side and the base side of each of them, the portions closer to the front end side than the connection portion 17 of the first arm 18 and the second arm 19 being holding portions (finger portions) 21, 22 for holding the workpiece W, and the movement of the first worktable 12 and the second worktable 13 driven by the first drive mechanism 15 and the second drive mechanism 16 in opposite directions relative to each other causes the first arm 18 and the second arm 19 to perform a clamping or releasing action, and the coordinated movement of the first worktable 12 and the second worktable 13 in the same direction causes the first arm 18 and the second arm 19 to perform a forward or return action.

[0015] In such a transfer mechanism, it is preferable that the first workbench 12 and the second workbench 13 are respectively composed of workbench bodies 12b and 13b having inclined guides 12a and 13a, and arm bases 12c and 13c provided to be movable along the inclined guides 12a and 13a. The bases of the first arm 18 and the second arm 19 are supported by the arm bases 12c and 13c so as to be rotatable. The inclined guides 12a and 13a of the first workbench 12 and the second workbench 13 are inclined in opposite directions so as to gradually separate upward from each other.

[0016] In the transfer mechanism 10 having such inclined guides 12a and 13a, it is preferable that the arm bases 12c and 13c are biased downward by a biasing force 20 toward the inclined guides 12a and 13a.

[0017] In addition, in any of the transfer mechanisms 10, it is more preferable that a plurality of sets of the first workbenches 12 and the second workbenches 13 are provided on the rail 11, and the first drive mechanism 15 moves the plurality of first workbenches 12 together, and the second drive mechanism 16 moves the plurality of second workbenches 13 together.

[0018] The transfer devices 40 and 45 of the present invention are characterized in that two of the transfer mechanisms 10 are arranged opposite to each other. In such transfer devices 40 and 45, it is preferable that the first workbench 12 of the two opposed transfer mechanisms 10 is driven by one first drive mechanism 15, and the second workbench 13 is driven by one second drive mechanism 16.

[0019] The transfer mechanism of the present invention does not require driving the entire feed rod, and can perform forward / return actions and clamping / loosening actions only by the first and second drive mechanisms that move the first and second workbenches along the rail. Therefore, the drive mechanism can be driven at high speed by a motor with low output, and the number of motors can be reduced.

[0020] If the first and second worktables are further moved separately from each other, the first and second arms and the first and second holding parts are opened, and at the same time, the front end moves laterally toward the base side and separates from the workpiece in the mold. Conversely, if the first and second worktables are moved closer to each other, the first and second arms and the first and second holding parts are closed, and at the same time, the front end moves laterally toward the mold side and approaches the workpiece in the mold. Therefore, the cooperation between the mold and the holding part is good, and space saving can be achieved. In addition, by the forward / return motion, when the first and second worktables move in the same direction, if the moving speeds of the respective worktables are changed, the worktables move relatively in opposite directions. By moving relatively in opposite directions like this, the forward / return motion can be performed while the first and second arms perform the clamping / loosening action. Thus, high-speed conveyance can be achieved.

[0021] The first and second worktables are respectively composed of a worktable main body having an inclined guide and an arm base provided so as to be movable along the inclined guide. The bases of the first and second arms are rotatably supported by the arm base. When the inclined guides of the first and second worktables are inclined in opposite directions so as to gradually separate upward, if the first worktable is brought closer to the second worktable, first, the worktable main body approaches the arm base. In addition, the first and second arms and the holding part are closed to clamp the workpiece. After clamping the workpiece, if the first and second worktables are further brought closer to each other, the arm bases cannot approach further. Therefore, the arm bases rise, and the first and second arms can be moved upward.

[0022] If the first and second worktables are separated from each other from this state, the arm bases descend. Thereby, the first and second arms can be moved downward. In addition, if the first and second worktables are further separated from each other, the first and second arms release the workpiece. Therefore, there is no need to separately provide an upward / downward drive source.

[0023] When the first and second worktables are composed of the worktable main body having the inclined guide and the arm base, when the arm base is biased downward toward the inclined guide, the clamping action is more reliable. In addition, when the first and second worktables are moved in the direction of separating from each other, the descending action of the arm base is more reliable.

[0024] In any of the transfer mechanisms, when a plurality of sets of the first and second worktables are provided on the track, and the first drive mechanism moves a plurality of the first worktables together and the second drive mechanism moves a plurality of the second worktables together, a plurality of workpieces can be conveyed to the next worktable together.

[0025] The transfer device of the present invention can convey large workpieces through the coordinated actions (or coordinated movements) of the first arm and the second arm that face each other. In such a transfer device, when the first workbench of the two opposing transfer mechanisms is driven by a first drive mechanism and the second workbench is driven by a second drive mechanism, the number of drive mechanisms can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1A FIG. [X] is a top view showing an embodiment of the transfer mechanism of the present invention in a released state, Figure 1B and Figure 1C FIGS. [X] and [X] are a front view and a side view thereof.

[0027] Figures 2A - 2C FIGS. [X], [X], and [X] are a rear perspective view, an exploded perspective view, and a front perspective view of the first workbench (also serving as the second workbench), respectively, Figure 2D FIG. [X] is a front perspective view of the arm base.

[0028] Figure 3A and Figure 3B FIGS. [X] and [X] are a top view and a front view showing the clamping state of the transfer mechanism shown in Figure 1A FIG. [X].

[0029] Figure 4A and Figure 4B FIGS. [X] and [X] are a top view and a front view showing the clamping and upward state of the transfer mechanism shown in Figure 1A FIG. [X].

[0030] Figure 5 FIG. [X] is a top view showing an embodiment of the transfer device of the present invention.

[0031] Figure 6A FIG. [X] is a top view showing another embodiment of the transfer device of the present invention, Figure 6B and FIG. [X] is a front view thereof.

[0032] Figure 7A and Figure 7B FIGS. [X] and [X] are a top view and a front view showing yet another embodiment of the transfer device of the present invention in a released state.

[0033] Figure 8 FIGS. [X] and [X] are a top view and a front view showing the clamping state of the transfer device shown in Figure 7A FIG. [X].

[0034] Figure 9A and Figure 9B FIGS. [X] and [X] are a top view showing the clamping state and the released state of another embodiment of the transfer mechanism of the present invention, Figure 9C FIG. [X] is Figure 9B a front view of FIG. [X], Figure 9D and FIG. [X] is a top view of the state where the pliers fulcrum is removed. DETAILED DESCRIPTION OF THE INVENTION

[0035] Figure 1A The transfer mechanism 10 shown is composed of a rail 11, a first and second workbench 12 and a second workbench 13 arranged on the rail 11 in a freely sliding manner, a clamp mechanism 14 arranged across the two workbenches, a first drive mechanism 15 and a second drive mechanism 16 for driving the respective workbenches 12, 13 along the rail 11. The clamp mechanism 14 is composed of the first arm 18 and the second arm 19 and a pin (clamp fulcrum) 17 for rotatably connecting the parts between the front end side and the base side of the respective arms 18, 19. A tension spring 20 is interposed between the first workbench 12 and the second workbench 13.

[0036] As Figure 1B shown, the thickness near the front ends of the first arm 18 and the second arm 19 is set to be half, and they are connected by the pin (clamp fulcrum) 17 so as to be rotatable in the horizontal plane. The portions closer to the front end side than the pin 17 are holding portions 21, 22 for gripping the workpiece W. The base portions of the arms 18, 19 are respectively mounted on the workbenches 12, 13 so as to be rotatable about a support shaft (arm fulcrum) 25. As in the present embodiment, in the case where each of the arms 18, 19 is formed of a single plate, the front end side of one arm may be formed in a single-peak U-shaped (convex) shape, the front end side of the other arm may be formed in a double-peak U-shaped (concave) shape, and they may be connected and combined in a state where the convex and concave portions of each other are engaged by the pin 17. Alternatively, one arm may be formed of two plates sandwiching the arm formed of another plate. Or, they may be respectively formed of two plates.

[0037] The first workbench 12 and the second workbench 13 are reversed left and right and are substantially the same, so the first workbench 12 on the left side will be mainly described. The workbench 12 is composed of a workbench main body 12b having an inclined guide 12a and an arm base 12c arranged so as to be slidable along the inclined guide 12a. The tension spring 20 is interposed between the respective arm bases 12c, 13c and applies a force in the direction of shortening the distance between the arm bases 12c, 13c. The inclined guides 12a, 13a of the two workbenches 12, 13 are inclined in opposite directions so as to gradually separate upward. That is, they are inclined such that the opposite sides of the two workbenches 12, 13 are lower and the other sides are higher.

[0038] The upper part of the workbench main body 12b is composed of a plate having a substantially triangular shape, and a groove for a guide is formed through the plate in parallel with the inclined surface of the substantially triangular plate as the inclined guide 12a. The inclined guide 12a may be formed of a protrusion or the like in addition to the groove. As Figures 2A - 2DAs shown, a groove 12e into which the upper part of the workbench main body 12b is inserted is formed on the lower surface of the arm base 12c. In addition, two guide rollers 12f that slide or roll in the groove of the inclined guide 12a are installed at the lower end of the arm base 12c. The guide rollers 12f are connected to the arm base 12c via guide pins 12g, and these guide rollers 12f roll in the groove of the inclined guide 12a in a rotatable manner. A pin or a slider may be provided instead of the guide rollers 12f. A sliding portion 26 that moves along the rail 11 is provided at the lower end of the workbench main body 12b (refer to Figure 1C ). The rail 11 and the sliding portion 26 may be constituted by a linear ball guide sandwiching balls in addition to a sliding linear guide. The rail 11 is supported by a support member 27.

[0039] In the present embodiment, the groove of the inclined guide 12a penetrates the plate of the workbench main body 12b, but shallow grooves that do not penetrate may be provided on both sides. In addition, the workbench main body 12b is a plate with an inclined surface at the upper end, and a groove 12e into which the upper part of the plate is inserted is formed in the lower part of the arm base 12c. Conversely, a groove may be formed at the upper end of the workbench main body 12b into which the lower part of the arm base 12c is inserted.

[0040] In addition, in the present embodiment, the two arm bases 12c and 13c are urged to approach each other by a tension spring 20. In addition, the two arms 18 and 19 are urged in the direction of closing toward the base side around a pin (pliers fulcrum) 17. Therefore, for example, when the workbenches 12 and 13 approach each other from the Figure 1A , Figure 1B state, the arm bases 12c and 13c do not rise along the grooves of the inclined guides 12a and 13a, and the closing operation takes precedence as in Figure 3A , Figure 3B . Thus, the switch operation is stable.

[0041] As described above, in the present embodiment, since the two arm bases 12c and 13c are urged to approach each other by a tension spring 20, a single tension spring can serve as a biasing device for the two arm bases 12c and 13c (the biasing device between the arm bases 12c and 13c and the workbench main bodies 12 and 13). In addition, the magnitudes of the acting forces can be made the same. However, tension springs may be respectively installed between the workbench main bodies 12b and 13b and the arm bases 12c and 13c to bias each arm base 12c and 13c obliquely downward along the groove of the inclined guide 12a. As the tension spring, a tension coil spring is preferably used. A compression coil spring may also be interposed between the workbench main bodies 12b and 13b and the arm bases 12c and 13c.

[0042] The holding portions 21 and 22 are formed to have a gap that is the same as or slightly narrower than the thickness or diameter of the workpiece W when closed (refer toFigure 3A )。It is also possible to paste an elastically deformable sheet or the like on the surfaces of the holding parts 21 and 22 that come into contact with the workpiece to absorb manufacturing errors or control errors. The swinging angle of one arm 18 around the arm fulcrum 25 preferably has the state where the arm 18 is opened and is horizontal with respect to the longitudinal direction of the first connecting rod 28 as 0°, the initial arm angle (the angle when released) is about 0° to 30°, and the angle when clamping is about 60° to 80°. When the initial arm angle is near 0°, it is necessary to apply an initial force around the arm fulcrum 25 through the torsion spiral spring 20a or the leaf spring so that the arms 18 and 19 move toward the clamping side when the two arm bases 12c and 13c are about to approach (refer to Figure 9A 、 Figure 9B ). It is also possible to use the torsion spiral spring 20a for applying the initial force around the arm fulcrum 25 as an alternative to the tension spring 20. If the initial arm angle is about 30°, the clamping / loosening operation can be performed only by the tension spring 20. The ratio of the length of the base side of the arm 18 (the distance between the pliers fulcrum 17 and the arm fulcrum 25) to the length of the holding part 21 is preferably about 2:1 to 5:1. Thus, the force amplification effect generated by the pliers mechanism 14 is about 2 to 5 times.

[0043] Return to Figure 1A , the first drive mechanism 15 and the second drive mechanism 16 are composed of a first connecting rod 28 fixed to the front surface (the lower side in the figure) of the first workbench 12 on the left side in the figure via a gasket 28a, a second connecting rod 29 fixed to the back surface (the upper side in the figure) of the second workbench 13 on the right side via a gasket 29a, and a first motor M1 and a second motor M2 that independently drive these connecting rods 28 and 29. A gap 29b is provided between the first workbench 12 and the second connecting rod 29. Each of the motors M1 and M2 and the connecting rods 28 and 29 can be connected via a rotation-linear motion conversion mechanism such as a combination of a ball screw and a ball nut (refer to Figure 4A and Figure 4B ) and the like.

[0044] Next, the operation of the transfer mechanism 10 configured as described above, particularly the operation around the arm, will be described. In this transfer mechanism 10, as Figure 1A shown, the state where the two workbenches 12 and 13 are separated is the released state. In this state, the arms 18 and 19 expand from each other, and the front ends move (recede) toward the rail 11 side. The holding parts 21 and 22 also expand and move away from the workpiece W placed on a mold or a stop table or the like. In addition, as Figure 1B shown, the arm bases 12c and 13c descend to the lower end.

[0045] If the workbench bodies 12b and 13b are driven from this state by the drive mechanisms 15 and 16 so as to approach each other, then as Figure 3AAs shown, the distance between the base sides of the arms 18 and 19 becomes narrower. In addition, the first arm 18 and the second arm 19 rotate around the arm fulcrum 25 in a closed manner. As a result, the holding portions 21 and 22 are closed to clamp the workpiece W on the mold (clamping action). At this time, the stretched tension spring 20 is relaxed, but the tensile force remains. The acting force of the tension spring 20 can be used as the clamping force for the workpiece.

[0046] If from Figure 3A , Figure 3B state, if the left and right table bodies 12b and 13b are further approximated to each other, the holding portions 21 and 22 clamp the workpiece W, so the arms 18 and 19 will not close further. In addition, as Figure 4A , Figure 4B shown, the arm bases 12c and 13c rise along the inclined guides 12a and 13a (upward movement). At this time, the holding portions 21 and 22 rise while clamping the workpiece W. For example, the formed workpiece W is lifted from the mold or the like. The rising end is restricted by the upper stopper 12h. If the movements of the table bodies 12b and 13b are symmetric about the left and right and the angles of the inclined guides 12a and 13a are the same, the arm bases 12c and 13c rise at a right angle with respect to the rail 11. Here, according to the control of the rotational speeds of the first motor M1 and the second motor M2, it is also possible to rise along an arbitrary trajectory such as an inclination. The descending trajectory is the same.

[0047] If from Figure 4A , Figure 4B state, if the first table 12 and the second table 13 are simultaneously moved in the same direction (for example, Figure 4A right direction) at the same speed by the drive mechanisms 15 and 16, the workpiece W moves in this direction. For example, it is conveyed to the table of the next mold or the like (forward movement). In addition, from Figure 3A , Figure 3B state, if the first table 12 and the second table 13 are simultaneously moved in the same direction (for example, Figure 3A right direction), and if the first table 12 is moved faster than the second table 13 at this time, it is also possible to convey the workpiece W while rising to the table of the next mold or the like. When the movements of the tables 12 and 13 are accurately synchronized, the force of the holding portions 21 and 22 grasping the workpiece W does not relax, and the workpiece W can be stably conveyed.

[0048] After the workpiece W is conveyed to the next table, they move in opposite directions to separate the distances between the first table 12 and the second table 13. Even if the distances between the first table 12 and the second table 13 are separated, since the tension spring 20 applies a force in the direction to close the arms 18 and 19, the arms 18 and 19 grasp the workpiece W. In addition, the first arm base 12c and the second arm base 13c descend along the inclined guides 12a and 13a, and the workpiece W also descends (refer toFigure 3B , downward movement). The descending end is restricted by the lower stopper 12j. Additionally, during the conveyance of the workpiece W, if the first table 12 is moved slower than the second table 13, the workpiece W can also be conveyed while descending. By performing upward and downward movements during the conveyance, high-speed conveyance can be achieved.

[0049] If driven from this state in a manner that further separates the table bodies 12b and 13b, the arm bases 12c and 13c will not descend further. Therefore, as the table bodies 12b and 13b separate, the arms 18 and 19 open, and the holding parts 21 and 22 open (refer to Figure 1A , Figure 1B ). Thereby, the workpiece W is placed on the next table (release action). At this time, as shown in Figure 1A , the holding parts 21 and 22 move (recede) in a manner that separates from the center of the die or the like. Additionally, in this state, the first table 12 and the second table 13 move together in the return direction (return action), and stamping is performed during this period. When the tables 12 and 13 return to the original tables, it starts over from the initial clamping action.

[0050] Furthermore, when the upper die is large and it is not sufficient to avoid interference with the upper die only by moving the holding parts 21 and 22 toward the rail 11 side, a return action for only half the pitch can be performed. In this state, the transfer mechanism is stopped, stamping is performed, and after the upper die rises, the remaining half-pitch return action is continued. Thus, since the holding parts 21 and 22 retract (stand by) at the intermediate position between the dies of adjacent processes, interference between the holding parts 21 and 22 and the dies can be further avoided.

[0051] Next, a description will be given of an embodiment of a single-rail type three-dimensional transfer device with reference to Figure 5 . This transfer device 30 basically directly uses the transfer mechanism 10 of Figure 1A . A plurality of clamp mechanisms (holding mechanisms) 31 each composed of a first arm 18 and a second arm 19, etc. are provided on a single rail 11 so as to be freely movable. Only two are shown in Figure 5 , but depending on the number of processing steps of the press equipment, etc., there can be three or more, for example, five to ten, etc. The clamp mechanisms 31 are arranged at intervals with the pitch of the die (feed pitch). Similar to the clamp mechanism 14 of Figure 1A , Figure 1B , each clamp mechanism 31 includes: a first arm 18, a second arm 19, a pin 17, tables 12 and 13, and a tension spring 20.

[0052] In addition, the table bodies 12b of the respective first tables 12 of the transfer mechanism are connected to each other by the first connecting rods 28, and are driven to travel together in the same direction and by the same distance along the track 11 by the first motor M1. The first connecting rods 28 are fixed to the front surfaces of the table bodies 12b ( Figure 5 on the lower side). In the present embodiment, an external thread 32 is connected to the output shaft of the first motor M1, and the first connecting rod 28 is fixed to a nut 33 that is screwed onto the external thread 32. Both ends of the external thread 32 are rotatably supported by bearings 35, 35 such as ball bearings provided on the frame 34. Preferably, the external thread 32 and the nut 33 are a ball screw and a ball nut.

[0053] The same applies to the second tables 13. The table bodies 13b of the second tables 13 of the transfer mechanism are connected to each other by the second connecting rods 29, and are driven to travel via the nut 33 and the external thread 32 by the second motor M2. In addition, the second connecting rods 29 are fixed to the back surfaces of the table bodies 13b opposite to the first connecting rods 28 ( Figure 5 on the upper side). Thereby, interference or sliding contact between the first connecting rod 28 and the second connecting rod 29 is avoided.

[0054] Preferably, the first motor M1 and the second motor M2 are servo motors, whereby it is possible to easily control the stop positions, moving speeds, synchronous movements, etc. of the first table 12 and the second table 13 respectively. In addition, according to the control programs of the first motor M1 and the second motor M2, the conveying direction of the workpiece can also be Figure 5 either the right direction or the left direction. In addition, the feed pitch (the length of forward and return) of the workpiece can be arbitrarily selected.

[0055] In the transfer device 30, the weights of the plurality of tables 12, 13, arms 18, 19 and connecting rods 28, 29 are supported by the track 11 and the support members ( Figure 1B symbol 27). Therefore, compared with a transfer device using a feed rod, the inertia of the moving part is small. Therefore, even a low-output motor can be driven at high speed. In addition, since no motor or speed reducer is provided in the movable part, the motor load can be further reduced.

[0056] Next, referring to Figure 6A , Figure 6BAn embodiment of a three-dimensional transfer device of the double-rail type will be described. The transfer device 40 is basically a device formed by relatively combining two sets of the three-dimensional transfer devices 30 of the single-rail type. The holding parts 21 and 22 are arranged opposite to each other, and the ends of a workpiece W are clamped by the holding parts 21 and 22 of their respective clamp mechanisms. In addition, after moving upward, forward, and downward while holding the workpiece by the holding parts on both sides, it can be conveyed to the next die by releasing. After releasing, it returns to the position of the original die. Stamping is performed during the return.

[0057] In addition, two external threads, two nuts, two motors M1 and M2 can also be used for each single-rail type transfer device. However, in the Figure 6A device, the first link rods 28 of the transfer mechanism on the inner side (the upper side in the figure) and the first link rods 28 of the transfer mechanism on the outer side (the lower side in the figure) are connected by the first cross bar 41. Thus, the external threads 32, nuts 33, and motor M1 can be used in common. The second link rods 29 are also connected by the second cross bar 42 in the same way. Thus, the number of components can be reduced and the control can be simplified.

[0058] Figure 7A and Figure 7B An embodiment of a two-dimensional transfer device of the double-rail type is shown. The transfer device 45 does not have an upward / downward mechanism. That is, as Figure 7B shown, the worktables 12 and 13 are not divided into a main body and an arm base, but are configured as one body, or multiple components are fixed as one body. The workpiece W is clamped by the holding parts 21 and 22 of the clamp mechanism 46 on the die (refer to Figure 8 ), moves forward while maintaining the same feeding height, and is released in the next die (refer to Figure 7A ). Then, the clamp mechanism 46 that does not hold the workpiece returns, and stamping is performed during this period. When upward / downward movement of the workpiece W is required, it is performed by a die buffer or a lifting mechanism assembled in the die.

[0059] In Figure 7A , Figure 7B the two-dimensional transfer device 45, the first link rods 28 are connected to each other by the first cross bar 41, and the second link rods 29 are connected to each other by the second cross bar 42. In addition, the three-dimensional transfer devices 30 and 40 can perform two-dimensional movements by controlling the motors. However, Figure 7A , Figure 7B the transfer device 45 is a two-dimensional dedicated device that omits the upward / downward mechanism, so the inertia is further reduced, and it can be driven at high speed by a motor with low output.

[0060] In addition, when the first workbench 12 and the second workbench 13 are moved in the same direction by forward / return actions, if the moving speeds of the workbenches 12 and 13 are changed, the workbenches 12 and 13 move relatively in opposite directions. By moving relatively in opposite directions in this way, the first arm 18 and the second arm 19 can perform clamping / loosening actions while performing forward / return actions, thereby enabling the conveyance to be further speeded up.

[0061] Figures 9A - 9C As shown in the conveyance mechanism 50, a torsion coil spring 20a is interposed between the arm base 12c of the first workbench 12 and the first arm 18, and the torsion coil spring 20a applies a rotational force in the direction of clamping the first arm 18, that is, the counterclockwise direction in the figure. The coil portion of the torsion coil spring 20a is disposed around the support shaft 25, one end is locked to the first arm 18, and the other end is locked to the arm base 12c. A torsion coil spring 20a is also interposed between the second workbench 13 and the second arm 19, and the torsion coil spring 20a applies a rotational force in the direction of clamping the second arm 19, that is, the clockwise direction.

[0062] However, as Figure 9B shown, if the arms 18 and 19 are rotated until the left and right support shafts 25 and 25 are aligned with the pins 17, the arms 18 and 19 do not protrude inward, and it is easy to avoid interference between the arms and the die during stamping. However, in this state, even if a force is applied in the direction of bringing the left and right arm bases 12c and 13c closer to each other, no component force for rotating the arms 18 and 19 is generated. Therefore, as Figure 9A shown, if torsion coil springs 20a and 20a that apply a rotational force to the arms 18 and 19 are provided, an initial rotational force can be applied by the torsion coil spring 20a. In addition, once the rotation starts, the clamping / loosening action and the upward / downward action can be continued smoothly.

[0063] As described above, the torsion coil springs 20a and 20a, particularly as Figure 9B shown, in the case where the arms 18 and 19 are extended until the left and right support shafts 25 and 25 are aligned with the pins 17 connecting the arms 18 and 19, they can assist the action of the tension coil spring 20 that applies a force in a manner of bringing the arm bases 12c and 13c closer to each other. In addition, when sufficient clamping force can be ensured only by providing the torsion coil springs 20a and 20a, the tension coil spring 20 can be omitted.

[0064] It is preferable to provide stoppers between the arms 18 and 19 and the arm bases 12c and 13c so that the arms 18 and 19 do not rotate beyond a right angle with respect to the rail 11. In this case, before the two arms 18 and 19 are connected by the support shaft 25, as Figure 9DAs shown, arms 18 and 19 are rotated to be perpendicular to rail 11. It is sufficient to have torsion coil springs 20a, 20a on only one of the left and right sides, but when they are provided on both sides, the operation is smooth.

[0065] Although several embodiments have been described above, the present invention is not limited to these and various modifications can be made. For example, in the above-described embodiment, the rotation of the motor is converted into the linear motion of the worktable using an external thread (or ball screw) and a nut (or ball nut), but a linear motor can also be interposed between the rail and the worktable to directly perform linear drive. Additionally, a winding element such as a wire rope or a chain can be used to convert the rotation of the motor into the reciprocating linear motion of worktables 12 and 13.

[0066] Alternatively, nuts (or ball nuts) can be fixed to the back surfaces of the plurality of first worktables 12, and one external thread (or ball screw) screwed with them can be rotationally driven by the first motor, and nuts (or ball nuts) can be fixed to the front surfaces of the plurality of second worktables, and they can be driven by the second motor through one external thread (or ball screw).

[0067] In addition, in the case of a double-rail type conveying device, in addition to clamping the end portion of the workpiece by the holding portion, when the relatively arranged holding portions approach the center side, both sides of the workpiece can be clamped, and when they are separated from the center side, the workpiece can be released. In the case of a workpiece having a flange, more stable conveyance can be achieved by clamping the lower surface side of the flange.

Claims

1. A transfer mechanism, comprising: a track; a first workbench and a second workbench, which are movably arranged on the track; a first arm and a second arm, the bases of which are rotatably supported by the first workbench and the second workbench respectively; and a first driving mechanism and a second driving mechanism, which move the first workbench and the second workbench along the track independently respectively. The transfer mechanism is configured to: The first arm and the second arm and a pliers fulcrum for rotatably connecting the parts between the front end side and the base side of the first arm and the second arm respectively form a pliers mechanism, and the part closer to the front end side than the pliers fulcrum is a holding part for holding a workpiece. The opposite-direction movement of the first workbench and the second workbench driven by the first driving mechanism and the second driving mechanism makes the first arm and the second arm perform clamping or releasing actions. The coordinated movement of the first workbench and the second workbench driven by the first driving mechanism and the second driving mechanism in the same direction makes the first arm and the second arm perform forward or return actions.

2. The transfer mechanism according to claim 1, wherein: The first workbench and the second workbench are respectively composed of a workbench main body with an inclined guide and an arm base arranged to be movable along the inclined guide. The bases of the first arm and the second arm are rotatably supported by the arm base. The inclined guides of the first workbench and the second workbench are inclined in opposite directions in a manner of gradually separating upward.

3. The transfer mechanism according to claim 2, wherein: The arm base is biased downward toward the inclined guide.

4. The transfer mechanism according to claim 1, wherein: Multiple sets of the first workbench and the second workbench are arranged on the track. The first driving mechanism moves multiple first workbenches together. The second driving mechanism moves multiple second workbenches together.

5. The transfer mechanism according to claim 2, wherein: Multiple sets of the first workbench and the second workbench are arranged on the track. The first driving mechanism moves multiple first workbenches together. The second driving mechanism moves multiple second workbenches together.

6. The transfer mechanism according to claim 3, wherein: Multiple sets of the first workbench and the second workbench are arranged on the track. The first driving mechanism moves multiple first workbenches together. The second driving mechanism moves multiple second workbenches together.

7. A transfer device, wherein: Two transfer mechanisms are arranged opposite to each other, and the transfer mechanism is the transfer mechanism according to any one of claims 1 to 6.

8. The transfer device according to claim 7, wherein: The first workbenches of the two opposite transfer mechanisms are driven by one first driving mechanism, and the second workbenches are driven by one second driving mechanism.

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