Workpiece transfer system

Abstract

To provide a workpiece transfer system in which a balancer handles heavy workpieces in cooperation with a robot, while the robot handles light workpieces.SOLUTION: A workpiece transfer system comprises: a vertical articulated robot 10; and a balancer 20 which has a C arm 25 configured to constantly move three-dimensionally in a perpendicularly drooped state. For handling a heavy workpiece Wr, a robot wrist part 16 is attached with a robot-side connection mechanism 18 instead of a robot hand 17, and connected with a balancer-side connection mechanism 29, and the balancer 20 grips, with a hand device 28, the heavy workpiece Wr, the hand device being attached to a balancer wrist part 26 at a lower end of the C arm 25, and the balancer handles the heavy workpiece Wr following guidance of the vertical articulated robot 10. For handling a light workpiece Ws, the robot-side connection mechanism 18 and the balancer-side connection mechanism 29 are separated from each other, and the robot wrist part 16 is attached with the robot hand 17 instead of the robot-side connection mechanism 18, and the vertical articulated robot 10 performs handling independently.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to, for example, a workpiece transport system, and more particularly to a workpiece transport system in which a balancer and a vertical articulated robot transport a workpiece separately and in which the balancer and a vertical articulated robot transport a workpiece in cooperation with each other. [Background technology]

[0002] The transport device disclosed in Patent Document 1 includes a balancer with a multi-joint structure and a vertical multi-joint robot, the tips of the balancer and the robot are connected by a connection mechanism, a hand device provided at the tip of the balancer grasps a workpiece, and the vertical multi-joint robot guides the hand device in a state where the load of the workpiece is almost not borne by the workpiece, thereby transporting the workpiece. When handling a workpiece, the operation of the balancer side is performed outside the operation of the vertical multi-joint robot side, and there is no interference between the vertical multi-joint robot and the balancer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-262304 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, there has been a need to be able to perform, in the same work area, for example, the task of lining up and packing multiple small, light-weight items into a box in a fast tact time, and then the task of stacking a heavy box packed with multiple items to a height of 1m on a 1m square pallet, even if it is at a slower tact time.

[0005] Recently, there are more opportunities to adopt collaborative robots that have high safety performance and can be operated in a shared area with workers. In addition, there are many cases where it is desirable to use a robot with as small an output as possible due to the demand for energy saving and space saving. Therefore, when we considered whether a small vertical articulated robot with low output, including a collaborative robot, could be applied to the work transport device disclosed in Patent Document 1, we found that it could be applied to the task of packing items into boxes, but it would be difficult to apply it to the task of stacking boxes filled with items on a pallet.

[0006] The present invention is intended to solve the above-mentioned problems. That is, the main object of the present invention is to provide a work transport system that includes a vertical articulated robot and a balancer, and in a connected state, the articulated robot guides the tip of the balancer with almost no load of the work, so that the balancer can handle heavy workpieces, and the articulated robot can handle small workpieces in a short tact time by releasing the connection with the tip of the balancer.

[0007] Another object of the present invention is to provide a conveying system in which the direction of a balancer's hand device can be easily changed to match the planar posture in which the workpiece is placed or to be placed when gripping and loading / unloading the workpiece.

[0008] Yet another object of the present invention is to provide an improved conveying system in which, although the independent second working range of the balancer is larger than and encompasses the first working range of the vertical articulated robot, when the vertical articulated robot and the balancer are connected, the working range of the balancer is disadvantageously narrowly limited to the first working range. The objective of the present invention is to provide a conveying system in which the working range of the balancer extends to an expanded range of the first working range even when guided by the vertical articulated robot. [Means for solving the problem]

[0009] In order to solve the above problems, the inventors have devised a transport system in which a small vertical articulated robot alone handles multiple small workpieces that can be transported by a small vertical articulated robot in a fast tact time, and a balancer and a small vertical articulated robot are connected to transport heavy workpieces, allowing the work to be safely performed even at a slower tact time, and have worked diligently on the development of this system. As a result, the present invention has been devised.

[0010] Furthermore, the inventors found that when the balancer and the vertical articulated robot are connected and the balancer loads and unloads workpieces onto a pallet, if the workpieces are stacked on the pallet facing in the same direction, there is a risk that the workpieces will easily collapse if the pallet sways sideways. Therefore, it is necessary to stack the workpieces on the pallet facing in a direction that differs by 90° for each layer, and it takes a lot of time to adjust the planar posture for this task.

[0011] Currently, in order to unload a workpiece by changing the direction in which the hand device attached to the tip of the balancer grips it, the vertical articulated robot must guide the balancer so that the center of the hand device coincides with the center of the planned unloading area, and the tip of the vertical articulated robot must be rotated around the center of the hand device, and when changing the unloading direction of the workpiece by 90 degrees, the tip of the vertical articulated robot must be rotated in half directions around the center of the hand device, which makes the operation very slow. Therefore, there is a demand for a system that allows the hand device to easily change the direction in which it grips the workpiece for unloading.

[0012] Furthermore, the inventors have discovered that although the independent second working range of the balancer is larger than and encompasses the first working range of the vertical articulated robot, when the vertical articulated robot and the balancer are connected, the working range of the balancer is disadvantageously limited narrowly within the first working range.

[0013] Specifically, it was found that if the working range of a vertical articulated robot in a planar view is, for example, a 1m radius, and the working range of the balancer is, for example, a 1.5m radius, a vertical articulated robot placed to the side of a 1m square pallet will not be able to handle workpieces at both corners at the front of the pallet, and that even if the vertical articulated robot alone can stack workpieces on a pallet to a height of 1m and the balancer is 1.5m high, when the balancer is connected to the vertical articulated robot, the height to which the balancer can stack workpieces on the pallet is limited to 1m.

[0014] Based on the above-mentioned findings, the inventors have organized their ideas. In conclusion, the present invention can be summarized as a workpiece transport system including a vertical articulated robot and a balancer having an articulated structure.

[0015] Therefore, in order to solve the above problem, the work transport system of a first aspect of the present application is configured to include a vertical multi-joint robot having a robot hand attached to a robot wrist section and handling a small, heavy workpiece that can be transported by a robot using the robot hand within a first operating range of a required size, and a multi-joint structure balancer that is attached to the vertical multi-joint robot, having a C-arm whose upper end is supported freely rotatably and moves in three dimensions while always hanging down vertically, the lower end of the C-arm being a balancer wrist section, a hand device is attached to the balancer wrist section, and a lifting balance mechanism keeps the hand device stationary while handling the small, heavy workpiece or before and after gripping the heavy workpiece that cannot be transported by a robot, and handles the heavy workpiece within a second operating range of a required size that includes the first operating range in response to guidance of the vertical multi-joint robot connected to the C-arm.

[0016] Furthermore, in order to solve the above-mentioned problems, in a work transport system according to a first different aspect of the present application, the robot wrist can chuck and unchuck the robot side connection mechanism instead of the robot hand, and the robot side connection mechanism chucked to the robot wrist can chuck and unchuck the balancer side connection mechanism provided on the side of the balancer wrist, and when handling the heavy workpiece, the robot wrist is equipped with the robot side connection mechanism and connected to the balancer side connection mechanism, the hand device equipped to the balancer wrist grasps the heavy workpiece, and the balancer handles it according to the guidance of the vertical articulated robot, and when handling the light workpiece, the robot side connection mechanism is detached from the balancer side connection mechanism, and the robot wrist detaches the robot side connection mechanism and attaches the robot hand, so that the vertical articulated robot handles it alone (see Figures 1, 3, 4A, 4B, 5A, and 5B).

[0017] As a work transport system according to a second aspect of the present application, in the first aspect, in addition to the configuration of the above-mentioned first invention aspect, the hand device provided at the lower end of the freely rotatable C-arm may be freely rotatably arranged coaxially with respect to the C-arm and configured to rotate by a required angle relative to the C-arm in accordance with the posture of the workpiece by a wrist rotation actuator attached to the C-arm (see Figures 4A, 4B, and 11).

[0018] A work transport system according to a third aspect of the present application, in the first or second aspect, may have a connection mechanism support section consisting of an upper horizontal section guided along the C-arm to be able to stroke the required dimension in the vertical direction, a lower horizontal section extending in the direction of the robot wrist axis, and an intermediate connecting section connecting the upper horizontal section and the lower horizontal section together at a required distance, and an actuator attached to the C-arm, wherein the upper horizontal section is positioned at either a lowered position or an raised position by the actuator, and the balancer side connection mechanism is provided at the protruding end of the lower horizontal section, so that the center of the balancer side connection mechanism is offset from the center of the C-arm by the required dimension (see Figures 4B and 5).

[0019] As a work transport system according to a fourth aspect of the present application, in the first or second aspect, a horizontal extension bracket of a required length is provided protruding horizontally from the lower side of the C-arm in the direction of the robot wrist axis, the balancer side connection mechanism is provided at the extension end of the horizontal extension bracket, and the center of the balancer side connection mechanism is offset from the center of the C-arm by a required dimension (see Figure 6).

[0020] As a work transport system according to a fifth aspect of the present application, in the first or second aspect, it may have a horizontal guide of a required length protruding horizontally from the lower side of the C-arm in the direction of the robot wrist axis, and a horizontally movable block that is slidable on the horizontal guide and fixed at an appropriate position, the balancer side connection mechanism is provided on the horizontally movable block, and the center of the balancer side connection mechanism is variably offset from the center of the C-arm (see Figure 7).

[0021] As a work transport system according to a sixth aspect of the present application, in the first or second aspect, it may have a vertical guide attached to the side of the C-arm, and a lifting block guided by the vertical guide and fixed at an appropriate height position, and the balancer side connection mechanism may be provided on the lifting block (see Figure 8).

[0022] As a workpiece transport system according to a seventh aspect of the present application, in the first or second aspect, instead of the connection mechanism support part, it may have a balancer side connection mechanism fixed to the lower end of the C-arm, and an upper balancer side connection mechanism that is slidable up and down from an upper position close to the second balancer side connection mechanism of the C-arm to a position higher by a required dimension and is positioned so as not to interfere with the second balancer side connection mechanism in a plan view (see Figure 9).

[0023] As a work transport system relating to an eighth aspect of the present application, in the first or second aspect, the vertical articulated robot may be installed on a first fixed post of a required height, and the balancer may be installed on a second fixed post that is higher than the first fixed post by a required amount, and when the vertical articulated robot and the balancer work together to handle the heavy workpiece, the multiple arms on the balancer side may operate outside the multiple arms on the vertical articulated robot side so that the arms do not interfere with each other (see Figure 1).

[0024] As a work transport system relating to the ninth aspect of the present application, in the first or second aspect, the vertical articulated robot may solely handle and box up a plurality of small workpieces placed on a table in succession to form a boxed body of heavy workpieces, and further include the table and the pallet when the plurality of heavy workpieces that have been boxed up in succession on the table are loaded in succession onto a pallet placed on the floor by the hand device of the balancer (see Figures 1 and 2).

[0025] As a work transport system according to the tenth aspect of the present application, in the first or second aspect, a conveyor for transporting small-weight workpieces, a second conveyor for transporting small-weight workpieces, and a conveyor for transporting large-weight workpieces may be arranged within the operating range of the vertical articulated robot (see Figure 10).

[0026] As a workpiece transport system relating to an eleventh aspect of the present application, in the second aspect, when the robot side connection mechanism is connected to the balancer side connection mechanism and the balancer moves and handles based on the guidance of the articulated robot, the division of control between the control unit of the balancer and the control unit of the vertical articulated robot may be such that the control unit of the balancer only controls the elevation angle of the A-arm which determines the height of the C-arm, and the control unit of the vertical articulated robot, in addition to controlling its own movement, also unifies the extension and contraction movement of the actuator attached to the C-arm, the chucking movement of the hand device, and the rotation angle of the hand rotation drive means. Effect of the Invention

[0027] The main object of the present invention is to provide a work transport system which comprises a vertical articulated robot and a balancer, and which, when connected, allows the articulated robot to guide the tip of the balancer with almost no load of the workpiece, enabling the balancer to handle heavy workpieces, and which allows the articulated robot to handle small workpieces in a fast tact time by disconnecting from the tip of the balancer.

[0028] In addition, according to the present invention, a conveying system can be provided in which the direction of the balancer's hand device can be easily changed to match the planar posture in which the workpiece is placed or to be placed when grasping and unloading the workpiece.

[0029] Furthermore, according to the present invention, although the independent second working range of the balancer is larger than and encompasses the first working range of the vertical articulated robot, when the vertical articulated robot and the balancer are connected, there is the disadvantage that the working range of the balancer is narrowly limited to the first working range.It is possible to provide an improved work transport system so that the working range of the balancer extends to an expanded range of the first working range even when guided by the vertical articulated robot. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is an overall perspective view of a workpiece transport system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a planar operating area of ​​a vertical articulated robot and a planar operating area of ​​a balancer in the workpiece transport system according to the embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram showing a process of connecting the robot wrist and the robot hand in the workpiece transport system according to the embodiment of the present invention. [Figure 4A] FIG. 4A relates to a workpiece transport system according to a modified example of the present invention, and shows a prototype in which a connection mechanism support part is provided in a small protruding manner on the lower side surface of the C-arm and a balancer-side connection mechanism is provided on the connection mechanism support part. [Figure 4B] FIG. 4B is a diagram showing a configuration in which a connection mechanism support part of a Z-shaped bracket is provided on a C-arm so as to be movable up and down, and a balancer-side connection mechanism is provided on this, thereby expanding the operating range of handling of the hand device of the balancer. [Figure 5A] FIG. 5A is a diagram showing a state in which the connection mechanism support part of the Z-shaped bracket is held fixed at the top of the C-arm and the articulated robot has raised the connection part with the balancer by 1 m from a state in which the hand device is holding a heavy workpiece, in accordance with an embodiment of the present invention. [Figure 5B] FIG. 5B is a diagram showing a state in which the articulated robot has raised the connection part with the balancer by 1 m with the connection mechanism support part fixed to the lowest position relative to the C-arm, from a state in which the hand device is gripping a heavy workpiece with the connection mechanism support part fixed to the highest position in the work transportation system according to an embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing a configuration of a work transport system according to a modified example of the present invention, in which a balancer-side connection mechanism is provided at the tip of a connection mechanism support part, which is a rod-shaped horizontally protruding member, and an offset dimension from the center of the balancer-side connection mechanism to the center of the C-arm is a required length. [Figure 7]FIG. 7 relates to a work transport system according to a modified example of the present invention, and shows a configuration in which the system has a horizontal guide protruding horizontally from the C-arm, and a horizontally movable block which is slidable on the horizontal guide and fixed with a bolt or the like, in which a balancer-side connection mechanism is provided on the horizontally movable block, and the offset dimension from the center of the balancer-side connection mechanism to the center of the C-arm is variable. [Figure 8] FIG. 8 is a diagram showing a configuration of a workpiece transport system according to a modified example of the present invention, which includes a vertical guide and a lifting block, and in which the height position of the connection mechanism support part is vertically variable, enabling the upper handling range of the balancer to be expanded. [Figure 9] FIG. 9 is a diagram showing a configuration relating to a workpiece transport system of a modified example of the present invention, which has a balancer-side connection mechanism fixed to the lower part of the C-arm and a second balancer-side connection mechanism provided so as to be capable of sliding up and down, in which balancer-side connection mechanisms are provided on both sides and a robot-side connection mechanism is selectively connected to the upper or lower balancer-side connection mechanisms. [Figure 10] FIG. 10 is a diagram showing a modified example of a workpiece transport system according to the present invention, in which a conveyor for transporting small-weight workpieces, a second conveyor for transporting small-weight workpieces, and a conveyor for transporting heavy workpieces are arranged within the operating range of a vertical articulated robot. [Figure 11] Fig. 11(A) is a diagram showing a state in which a balancer cooperates with an articulated robot to spread heavy workpieces on a pallet in a work transport system according to an embodiment or a modified example of the present invention, and Fig. 11(B) is a diagram showing the hand device rotating around the center of the planar orientation of the workpiece while aligning the center of the planar shape of the hand device with the center of the planar orientation of the workpiece at the gripping position or the lowering position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] [Outline of the structure of the work transport system 1] As shown in FIG. 1, the work transport system 1 of the embodiment of the present invention comprises a balancer 20 and a vertical articulated robot 10 (hereinafter, sometimes simply referred to as the articulated robot), and the tip of the articulated robot 10 can be freely connected to and disconnected from the tip of the balancer 20. When the tips are connected to each other, a hand device 28 provided at the tip of the balancer 20 grasps a heavy workpiece (in FIG. 1, a plastic case C is shown as a whole containing a required number of small workpieces Ws without symbols; FIG. 3(D) shows a heavy workpiece Wr). The articulated robot 10 can guide the hand device 28 with almost no load of the workpiece, thereby handling the heavy workpiece. Apart from this handling, the tip of the articulated robot 10 can be disconnected from the tip of the balancer 20, and the articulated robot 10 can handle the small workpiece Ws by itself.

[0032] In this embodiment, a first fixed post 81 of a required height and a second fixed post 82 of a required height higher than the first fixed post 81 are installed on a system installation stand 80 having casters with stoppers on all four sides of the bottom surface, and the vertical articulated robot 10 is installed on the first fixed post 81, and the balancer 20 is installed on the second fixed post 82. The reason for providing the first fixed post 81 and the second fixed post 82 is to increase the operating range even if the length of each of the swivel bases 12 and 22 is shortened. The difference in length between the first fixed post 81 and the second fixed post 82 is to set the operating range of the balancer 20 higher so that it is included below the operating range of the vertical articulated robot 10.

[0033] As shown in Fig. 2, the vertical articulated robot 10 and the balancer 20 are placed on the side of the pallet P on a line passing through the center of the pallet P, which is, for example, 1 m square. Since the operating area R2 (for example, 1.5 m radius) of the balancer 20 is larger than the operating area R1 (for example, 1 m radius) of the vertical articulated robot 10, the vertical articulated robot 10 is placed at a position closer to the pallet P. This is so that when handling is performed in cooperation with the vertical articulated robot 10, particularly when handling is performed near the robot, both arms of the vertical articulated robot 10 and the balancer 20 can operate smoothly. The vertical articulated robot 10 and the balancer 20 may be placed in parallel with the pallet P.

[0034] [Configuration of vertical articulated robot 10] The vertical articulated robot 10 shown in FIG. 1 and FIG. 4B includes, for example, a connection plate 11 mounted and fixed on a first fixed post 81 at a required height, a rotating base 12 that is horizontally rotatable with respect to the connection plate 11 and can rotate horizontally approximately 360 degrees by a driving means (not shown), a first arm 13 whose base end is pivotally supported on the upper part of the rotating base 12 and whose tip side can be tilted up and down in a vertical plane by a driving means (not shown) attached to the rotating base 12, and a first arm 13 whose base end is pivotally supported on the tip of the first arm 13. The robot comprises a second arm 14, the tip of which can be tilted up and down in the same plane as the vertical plane on which the first arm 13 is tilted up and down by a driving means (not shown) attached to the pivot portion on the first arm 13 side, a third arm 15, the base end of which is provided at the tip of the second arm 14 and attached to the tip of the second arm 14, and which can be tilted up and down in the same plane as the vertical plane on which the second arm 14 is tilted up and down by two driving means (not shown), and a robot wrist 16, which is provided at the tip of the third arm 15 and can be rotated freely approximately 360 degrees.

[0035] The vertical articulated robot 10 has a configuration in which a robot hand 17 shown in Fig. 3 or a robot side connection mechanism 18 shown in Fig. 4B is selectively attached in an interchangeable manner to a robot wrist section 16 rotatably provided at the tip of a third arm 15, which has a first operating range R1 of a required size shown in Fig. 2 when the robot wrist axis is facing downward. When the robot hand 17 is attached, the robot handles a small, heavy workpiece Ws by itself, and when the robot side connection mechanism 18 is attached, it connects to a balancer side connection mechanism 29 attached to the side of the tip of the balancer 20 to guide the balancer 20.

[0036] Fig. 3 shows a process diagram for attaching a robot hand 17 to the robot wrist section 16. As shown in Fig. 3(A) and (B), the vertical articulated robot 10 is capable of attaching a robot hand 17 placed on a jig stand to the robot wrist section 16, and furthermore, as shown in Fig. 3(C), the robot hand 17 can grasp a small weight workpiece Ws.

[0037] As shown in Fig. 3(A), the robot wrist 16 has a flange 16a and a plurality of chuck jaws 16b protruding downward from a central hole of the flange 16a. As shown in Fig. 3(B), the robot hand 17 has a flange 16a and a plurality of chuck jaws 16b protruding downward from a central hole of the flange 16a, but is not limited to this configuration and is configured to have a chuck function that is suitable for the type of small and heavy workpiece Ws. Any of the gripping means may be used, such as gripping by magnetic suction, gripping by air suction, gripping by lifting up with a scraper, or other gripping means.

[0038] To connect, as shown in Fig. 3(A), the robot wrist 16 faces downward, is positioned directly above the robot hand 17 placed on the jig stand T2, and is lowered after aligning the center. Then, as shown in Fig. 3(B), the flange 16a is brought into close contact with the flange 16a, the control system wiring is electrically connected, and the multiple chuck jaws 16b of the robot wrist 16 enter the central hole of the flange 16a of the robot hand 17 and the multiple chuck jaws 16b are expanded, thus completing the connection, and the robot hand 17 can lift the robot wrist 16 together with the robot wrist 16. To separate from the chucked state, the robot wrist 16 is lowered to a state where it is placed on the jig stand T2, the chuck diameter of the multiple chuck jaws 16b is reduced, and then the robot wrist 16 is raised, completing the separation.

[0039] [Balancer 20 Configuration] As shown in FIG. 1, the balancer 20 includes a connection plate 21 mounted and fixed on a second fixed post 82, a swivel base 22 which can rotate horizontally approximately 360 degrees relative to the connection plate 21, an A arm 23 which has a weight (not shown) at its base end and is pivoted to a bifurcated portion at the upper part of the swivel base 22 at its midpoint near the base end and whose protruding end side can be tilted up and down, a B arm 24 which is supported by the protruding end of the A arm 23 and can rotate horizontally approximately 360 degrees relative to the A arm 23 while always remaining horizontal, and a C arm 25 which is supported by the protruding end of the B arm 24 so as to always maintain a vertical hanging state and can rotate horizontally approximately 360 degrees relative to the B arm 24, the lower end of the C arm 25 being a balancer wrist 26 to which a hand device 28 corresponding to the balancer wrist 26 can be attached and detached so as to be able to grip a heavy workpiece Wr. The structure for attaching and detaching the balancer wrist portion 26 to the hand device 28 may be a structure having an appropriate gripping function.

[0040] As a structure for enabling the C-arm 25 to maintain its position in a vertically hanging state and move in three dimensions, the B-arm 24 may not always be an arm that is horizontally rotatable while always maintaining a horizontal state as described above, but may be configured to be controlled to be tilted up and down like the second arm 14 of the vertical articulated robot 10, and may maintain the position of the C-arm 25 in a vertically hanging state using two parallel link mechanisms as in Patent Document 1. The hand device 28, configured to have a gripping function according to the type of heavy workpiece Wr, is prepared on the jig placement table T2.

[0041] The connection structure between the balancer wrist 26 and the hand device 28 may be the same as the connection structure between the robot wrist 16 and the robot hand 17 shown in Figures 3(A) and (B). In this embodiment, the hand device 28 is a clamping type hand device that is a pneumatic gripper or an electric gripper, but it may be gripping by magnetic suction, gripping by air suction, gripping by lifting up with a scraper, or any other gripping means.

[0042] The vertical axis (not shown) connecting the swivel base 22 and the A arm 23, the vertical axis (not shown) connecting the A arm 23 and the B arm 24, and the vertical axis (not shown) connecting the B arm 24 and the C arm 25 are all arranged in the vertical direction and can follow the horizontal guidance of the vertical articulated robot 10 with almost no resistance.

[0043] The B arm 24 is connected and supported by a parallel link mechanism 27a provided along the swivel base 22, so that the B arm 24 can always be kept horizontal even if the elevation angle of the A arm 23 varies.

[0044] The swivel base 22 is configured so that the moment around the connecting shaft (horizontal shaft: not shown) with the swivel base 22 is almost balanced by the lifting balance mechanism 27, specifically a weight (not shown) provided at the base end of the arm, and further has an operation function of lifting up and down the arm tip side by the extension and retraction operation of the air cylinder device 27b provided on the upper part of the swivel base 22 and connected to the base end of the arm. The swivel base 22 can maintain a required inclination state so that the weight of the workpiece to be gripped by the hand device 28 is measured and reflected in the operation of the air cylinder device 27b, and the stationary state is maintained before and after the workpiece is gripped. In addition, when the swivel base 22 detects, for example, by a pressure sensor, that the lifting or lowering force of the robot acts on the hand device 28, the air cylinder device 27b extends or retracts to assist the vertical guidance of the robot, so that the hand device 28 can follow.

[0045] The components of the balancer 20 of claim 1 of the present invention include a C-arm 25 whose upper end 25a is supported freely rotatably and which is always movable in three dimensions in a vertically hanging state, and whose lower end constitutes a balancer wrist 26, and a hand device 28 is attached to the balancer wrist 26, and a lifting balance mechanism 27 is used to keep the hand device 28 stationary before and after grasping a workpiece, and the hand device 28 follows the guidance of the vertical articulated robot 10 connected to the C-arm 25 to handle the workpiece.

[0046] [Connection structure between robot side connection mechanism 18 and balancer side connection mechanism 29] The vertical articulated robot 10 can handle small workpieces Ws weighing up to about 15-20 kg in a fast tact time, but cannot handle large workpieces Wr weighing more than 20 kg and up to about 30-40 kg on its own. In contrast, the balancer 20 has a multi-joint structure, but is capable of handling large workpieces Wr weighing about 30-40 kg because the swivel base 22 is structured so that the lifting force is supported by the lifting balance mechanism 27. However, the balancer 20 does not have an active function to handle on its own. Therefore, in the work transport system 1 according to the present invention (claim 1), the balancer 20 is connected to the vertical articulated robot 10 from the side thereof in order to handle the workpieces, and handling can be performed by the guidance of the vertical articulated robot 10.

[0047] For this reason, the vertical articulated robot 10 and the balancer 20 each have a connection mechanism that allows them to be freely connected and disconnected from each other, so that in the same work area, the vertical articulated robot 10 can handle small, heavy workpieces Ws by itself in a fast tact time, and the balancer 20 can handle large, heavy workpieces Wr by being guided by the vertical articulated robot 10.

[0048] The balancer 20 is provided with a balancer-side connection mechanism 29 having an upward flange 29a on the upper side of the hand device 28 that is gripped by the balancer wrist 26. In this case, in the configuration of a prototype included in the present invention, as shown in Fig. 4A, conventionally, the connection mechanism support part 40A protruding with a minimum offset to the side of the lower end of the freely rotatable C-arm 25, the balancer wrist support part 26A, and the balancer wrist shaft 26 were integral with the C-arm 25.

[0049] The connection structure between the robot side connection mechanism 18 and the balancer side connection mechanism 29 may be the same as the connection structure between the robot wrist 16 and the robot hand 17 described above. That is, as described above, the robot wrist 16 has a flange 16a and a plurality of chuck jaws 16b protruding downward, and the structure for connecting to the robot hand 17 is also present at the bottom of the robot side connection mechanism 18. The robot side connection mechanism 18 has a flange 18a, and the plurality of chuck jaws 18b enter and expand holes in the flange 29a at the center of the upper surface of the balancer side connection mechanism 29, and the flange 29a of the balancer side connection mechanism 29 on the side of the balancer wrist 26 and the flange 18a of the robot side connection mechanism 18 come into close contact with each other, and the positioning means is fitted in place.

[0050] [Supports small and heavy workpieces Ws and Wr] [Relationship between the operating range of the articulated robot 10, the operating range of the balancer 20, and handling] When handling a small and heavy workpiece Ws, if the handling is within the operating range of the articulated robot 10, the robot wrist 16 facing downward is lowered and attached to the robot hand 17 placed on the jig placement table T2, and the workpiece can be handled by the robot hand 17 in a fast tact time.

[0051] The balancer 20 can handle a heavy workpiece Wr by being guided by the articulated robot 10. In this case, the downward-facing robot wrist 16 is lowered to release the chuck of the robot hand 17 and place it on the jig stand T2, the robot wrist 16 is connected to the robot-side connection mechanism 18 on the jig stand T2 and raised, and the robot-side connection mechanism 18 is moved directly above the balancer-side connection mechanism 29 on the side of the balancer wrist 26 to align it and then lowered, thereby mechanically connecting the robot-side connection mechanism 18 and the balancer-side connection mechanism 29.

[0052] In addition, when the robot control unit 83 controls the connection part lifting actuator 41, wrist portion rotating actuator 26a, and chuck drive means of the hand device 28 of the balancer 20, a power supply circuit and a control circuit are connected to the connection part lifting actuator 41, wrist portion rotating actuator 26a, and chuck drive means of the hand device 28 from the robot side when the robot side connection mechanism 18 and the balancer side connection mechanism 29 are connected.

[0053] The handling motion range of the balancer 20 is larger than that of the articulated robot 10. Therefore, handling of a heavy workpiece Wr that is outside the handling motion range of the articulated robot 10 (for example, the range indicated by symbols a and b in FIG. 2) is performed by the balancer 20. However, since the handling of the balancer 20 is performed under the guidance of the articulated robot 10, the handling motion range is limited to be smaller than the handling motion range that the balancer 20 originally has. Therefore, in this embodiment, a measure is provided to expand the handling of the balancer 20 under the guidance of the articulated robot 10, which will be described in detail later.

[0054] When a plurality of types of light weight workpieces Ws and a plurality of types of small weight workpieces Ws are to be handled, a plurality of types of robot hands and a plurality of types of hand devices are prepared on the jig placement table T2 and are selectively used.

[0055] According to the work transport system 1 having the above-described configuration, for example, as shown in FIG. 1, the vertical articulated robot 10 can independently handle the task of aligning and packing multiple small workpieces Ws (parts or products) placed on the table T1 into a plastic case C placed on the table T1 in a fast tact time by mounting the robot hand 17 thereon. Then, for the task of stacking a boxed body (heavy workpieces Wr) in which multiple small workpieces Ws are packed into a plastic case C to a height of 1 m on a 1 m square pallet P placed on the floor (palletizing task), the robot connects and guides the tips of the balancer 20 and the boxes, and the hand device 28 of the balancer 20 grasps the boxes and arranges them in a spread-out state on the pallet P, and the boxes can then be stacked in multiple tiers to a height of 1 m.

[0056] Furthermore, when the articulated robot 10 pallets a small workpiece Ws onto a pallet P, both corners of the 1 m square pallet P on the side facing the robot are outside the handling range, and the robot alone cannot handle the small workpiece Ws. Therefore, in this case too, it is necessary to connect the articulated robot 10 to a balancer 20 and handle the small workpiece Ws using the hand device 28 of the balancer 20.

[0057] 11(A) shows the state in which the balancer 20 cooperates with the articulated robot 10 to spread heavy workpieces Wr on a pallet P. The size, number, and planar orientation (direction) of the heavy workpieces Wr are shown as an example. Regarding the number of layers, when stacking multiple layers on a 1m square pallet P, the workpieces are usually stacked up to a height of 1m, but may be stacked up to a height of 1.5m upon special request.

[0058] In terms of the laying method, in order to prevent the load from shifting even if the pallet P sways sideways, when laying in one layer as shown in Fig. 11(A), the layout in the next layer is rotated 90 degrees as a whole from the layout in Fig. 11(A). Therefore, as shown in Fig. 11(B), it is necessary to change the orientation of each heavy workpiece Wr by 90 degrees and place it in a planar position.

[0059] When considering the handling of the above example, several problems were found.

[0060] The first problem is that it is necessary to adjust the planar posture of the hand device 28 of the balancer 20 to the planar posture of the workpiece at the gripping position, and to adjust the planar posture of the workpiece required at the position where the workpiece gripped by the hand device 28 is to be lowered. Incidentally, in order to adjust the planar posture of the hand device 28 to the planar posture of the workpiece at the gripping position or the lowering position, as shown in FIG. 11(B), the multi-joint robot 10 is operated so that the connection part with the balancer 20 at the tip of the robot rotates around the center of the planar posture of the workpiece while guiding the multi-joint robot 10 to adjust the center of the planar shape of the hand device 28 of the balancer 20 (the center of the C-arm 25) to the center of the planar posture of the workpiece at the gripping position or the lowering position. If the multi-joint robot 10 tries to move around the center of the hand device 28, the hand device 28 of the balancer 20 also moves away from the center. Therefore, it was difficult to control and took a long time to adjust the posture.

[0061] Therefore, the workpiece transport system 1 of this embodiment is configured as follows to solve the first problem. As shown in Fig. 4A, the balancer wrist 26 provided at the lower end of the freely rotatable C-arm 25 was conventionally integral with the C-arm 25, whereas as shown in Fig. 4B, in this embodiment, the balancer wrist 26 is provided coaxially with the C-arm 25 so as to be free to rotate, and is attached to the C-arm 25. By guiding the articulated robot 10 with a wrist rotation actuator 26a (for example, a combination of a rotation motor and a gear mechanism) as shown in Fig. 11(B), the center of the C-arm 25 is aligned with the center of the planar orientation of the workpiece, and then the wrist rotation actuator 26a is rotated by a required angle α°, so that the planar orientation of the hand device 28 can be easily aligned with the planar orientation of the heavy workpiece Wr to be grasped or the planar orientation of the heavy workpiece Wr required at the position where the workpiece is to be lowered.

[0062] Conventionally, since the C-arm 25 is free to rotate, the balancer wrist 26 at the lower end of the C-arm 25 is free to rotate as one unit with the C-arm 25. However, in this embodiment, the balancer wrist 26 can be controlled to rotate separately from the free rotation of the C-arm 25 by the wrist rotation actuator 26a, making control easier and enabling the posture adjustment time to be significantly reduced.

[0063] Next, as a second problem, the range in which the balancer 20 connected to the articulated robot 10 can handle under the guidance of the articulated robot 10 is limited to be significantly smaller than the original operating range of the balancer 20 separated from the articulated robot 10. For example, when the robot hand 17 has an operating radius of 1 m facing downward, when the balancer 20 places a heavy workpiece Wr at a required position on the pallet P under the guidance of the articulated robot 10, it can be performed within the operating radius of 1 m of the robot hand 17 as shown in FIG. 2, but the front corners of the pallet P (the ranges of symbols a and b in FIG. 2) are outside the range and therefore cannot be performed. In addition, the height that the balancer 20 can stack on the pallet P under the guidance of the articulated robot 10 is limited to 1 m. Depending on the site, there is a need for stacking up to 1.5 m, but this cannot be met.

[0064] Therefore, the workpiece conveying system 1 of this embodiment is configured as follows to solve the second problem.

[0065] As shown in FIG. 4B, a C-arm 25 (an arm that is always hanging down) whose upper end is supported freely rotatably on the tip of a B-arm 24 is provided with a connection mechanism support part 40 which is a Z-shaped bracket, and an actuator 41 (e.g., an air cylinder device) for raising and lowering the connection mechanism support part 40 which moves the connection mechanism support part 40 in the vertical direction relative to the C-arm 25, and a balancer side connection mechanism 29 is provided on the protruding end of the connection mechanism support part 40, thereby solving the second problem mentioned above.

[0066] Conventionally, and in a prototype included in the scope of the present invention, as shown in FIG. 4A, a balancer-side connection mechanism 29 was provided on a connection mechanism support part 40A that protruded with a small offset dimension from the lower side surface of a C-arm 25, whose upper end is supported freely rotatably on the tip of a B-arm 24.

[0067] In the following description, an air cylinder device is used as the actuator 41 for lifting the connection mechanism support part, and the piston of the air cylinder device is connected to the connection mechanism support part 40, and when the piston is retracted, the connection mechanism support part 40 is fixed at the lowest position in the stroke range relative to the C-arm 25. However, the orientation of the air cylinder device may be changed so that when the piston of the air cylinder device is retracted, the connection mechanism support part 40 is fixed at the highest position in the stroke range relative to the C-arm 25. The actuator 41 for lifting the connection mechanism support part may be composed of a rack of a required length guided in the vertical direction along the C-arm 25, a servo motor fixed to the C-arm 25, and a pinion fixed to the output shaft of the servo motor and meshing with the rack, and the upper end part 40a of the connection mechanism support part 40 is fixed to the rack.

[0068] The connection mechanism support part 40 is generally Z-shaped and comprises an upper horizontal part 40a whose upper end is guided vertically along the C-arm 25 to be able to stroke by a required dimension, for example 500 mm, a lower horizontal part 40b extending horizontally in the direction of the robot wrist axis, and an intermediate connecting part 40c which connects the upper horizontal part 40a and the lower horizontal part 40b together at a required distance, for example 300 mm. The upper horizontal part 40a is positioned at either a lowered position or an elevated position by an actuator 41 for raising and lowering the connection mechanism support part.

[0069] Since the balancer-side connection mechanism 29 is provided at the protruding end of the lower end horizontal portion 40b of the connection mechanism support portion 40, the center of the balancer-side connection mechanism 29 is offset by a required dimension (300 mm longer than conventionally) from the center of the C-arm 25. Therefore, the planar range of handling of the balancer 20 guided by the articulated robot 10 can be expanded to the peripheral portion in planar view within the planar operating range of the main body of the balancer 20 when the connection mechanism support portion 40 is not provided.

[0070] When the piston rod of the air cylinder device 41, which is an actuator for raising and lowering the connection mechanism support part, is in a retracted state, and the connection mechanism support part 40 is fixed to the lowest position in the stroke range of the C-arm 25, the height to which the articulated robot 10 can be moved by the balancer 20's guidance is limited by the movement limit in the height direction of the articulated robot 10, just as when the connection mechanism support part 40 is not provided. For this reason, this is applied when, for example, workpieces are piled up to 1 m on a pallet P.

[0071] Then, by switching the piston rod of the air cylinder device to an extended state, the connection mechanism support part 40 is fixed at the top of the stroke range with respect to the C-arm 25. At this time, the height limit to which the balancer 20 can be moved by the guidance of the articulated robot 10 is 500 mm higher (1.5 m high) than when it is fixed at the lowest position, and the work can be handled up to a position on the pallet P that is 500 mm higher (1.5 m high).

[0072] This does not mean that it is necessary to switch the piston rod from the retracted state to the extended state when stacking up to 1m is completed, and then to stack up to 1.5m. When stacking from 1m to 1.5m, when the hand device 28 is lowered to grasp a workpiece, as shown in the left half of FIG. 5B, the piston rod of the air cylinder device 41, which is an actuator for raising and lowering the connection mechanism support part, is extended, so that the connection mechanism support part 40 is fixed at the top of the stroke range with respect to the C-arm 25, and the hand device 28 can be lowered to a level where it can grasp the workpiece. Then, when the hand device 28 grasps the workpiece and rises, the air cylinder device 41 is contracted, so that the connection mechanism support part 40 is fixed at the bottom of the stroke range with respect to the C-arm 25, and the hand device 28 can stack the workpiece to a height exceeding 1m by being guided by the articulated robot 10. After that, to continue stacking the workpiece to a height exceeding 1m, the air cylinder device 41 is alternately extended and contracted to grasp and stack the workpiece.

[0073] In Fig. 5A, the connection mechanism support part 40 is held in a fixed state at the top of the C-arm 25, the left side of Fig. 5A shows the hand device 28 of the balancer 20 gripping the heavy workpiece Wr guided by the articulated robot 10, and the right side of Fig. 5A shows the state in which the articulated robot 10 has raised the connection part with the balancer by 1 m. With this operation, the hand device 28 can perform a handling operation of lifting the heavy workpiece Wr onto the pallet P to a height of about 1 m guided by the articulated robot 10.

[0074] The left side of FIG. 5B shows that the connection mechanism support part 40 is held in a state fixed to the top of the C-arm 25, and the hand device 28 of the balancer 20 grasps the heavy workpiece Wr by the guidance of the articulated robot 10, and the right side of FIG. 5B shows that the air cylinder device 41 operates after the hand device 28 grasps the heavy workpiece Wr, the connection mechanism support part 40 is lowered 500 mm to the bottom relative to the C-arm 25, and the state is held fixed, and the articulated robot 10 raises the connection part with the balancer by 1 m. By operating the connection mechanism support part 40, the articulated robot 10 can be guided 500 mm higher than when the connection mechanism support part 40 is not operated. With this operation, the hand device 28 can perform a handling operation of lifting the heavy workpiece Wr to a height of about 1.5 m on the pallet P by the guidance of the articulated robot 10.

[0075] As shown in Fig. 4A, when the connection mechanism support part 40A is provided, the operating area of ​​the balancer 20 is limited by the guidance of the articulated robot 10, and in particular, handling up to a height of about 1 m is possible, and the planar operating area of ​​the balancer 20 is limited to a radius of about 1 m by the guidance of the articulated robot 10, and handling at both corners of the pallet P indicated by symbols a and b in Fig. 2 is not possible. In comparison, as shown in Fig. 4B, when the connection mechanism support part 40, which is a Z-shaped bracket, is provided, handling up to a height of about 1.5 m is possible, and when the connection mechanism support part 40 is provided, handling up to a radius of about 1.3 m is possible by expanding the offset amount by 300 mm, and handling at both corners of the pallet P indicated by symbols a and b in Fig. 2 is possible.

[0076] [Control of the multi-joint robot 10 and balancer 20] The control unit 83 of the articulated robot 10 performs unified control of the rotation angle of the rotation base 12, the elevation angle of the first arm 13, the elevation angle of the second arm 14, the elevation angle and rotation angle of the robot wrist 16, the operation of the robot side connection mechanism 18 and the balancer side connection mechanism 29, the chucking operation of the robot hand 17, the extension and contraction operation of the piston of the air cylinder device 41 which is an actuator for raising and lowering the connection mechanism support part which is a Z-shaped bracket attached to the C arm 25 of the balancer 20, the chucking operation of the hand device 28, and the rotation angle of the hand rotation drive means 29a. The control may be program control by specifying spatial coordinates, or may be teaching control. The control may be performed by recognizing the position and the workpiece with a camera or a sensor. When palletizing, even if the workpieces are stacked in the same plan view position, it is desirable to change the orientation of the workpieces by 90 degrees for each layer, so the height and orientation at which the workpieces are released from the chuck are also included in the objects of control. When calculating the rotation angle when driving the wrist rotation actuator 26a so that the orientation of the hand device 28 matches the orientation before gripping the heavy workpiece Wr and the orientation when placing it on a pallet, it is advisable to use encoders provided on the driving means of the robot and balancer, as well as other angle sensors and cameras that record the positional relationship.

[0077] The control unit 84 of the balancer 20 only controls the elevation angle of the A-arm 24, which determines the height of the C-arm 26. It is easier to construct a program for the extension and contraction movement of the piston of the air cylinder device 41 attached to the C-arm 26, the chucking movement of the hand device 28, and the rotation angle of the hand rotation drive means 29a if the control unit of the articulated robot 10 is in charge of these operations from the viewpoint of recognizing the handling as an extension of the articulated robot 10, but the control unit of the balancer 20 may be in charge of these operations.

[0078] [Modification 1: Claim 4] Instead of the connection mechanism support part 40 provided in the above embodiment, a horizontally extending bracket of a required length may be provided protruding horizontally from the lower side surface of the C-arm 25 in the direction of the robot hand 17, and the balancer side connection mechanism 29 may be provided at the extending end of the horizontally extending bracket, with the center of the balancer side connection mechanism 29 being fixed at an offset dimension of 300 mm from the center of the C-arm 25. This allows the planar range of handling of the balancer 20 guided by the articulated robot 10 to be expanded by 300 mm in offset dimension, and therefore can be expanded to the peripheral part in planar view within the planar operating range of the main body of the balancer 20 when the connection mechanism support part 40 is not provided. [Modification 2: Claim 4]

[0079] As shown in Fig. 6, instead of the connection mechanism support part 40 provided in the above embodiment, a connection mechanism support part 40B, which is a rod-shaped horizontally protruding member, may be provided, and the balancer side connection mechanism 29 may be provided at the tip of the connection mechanism support part 40B, and the offset dimension from the center of the balancer side connection mechanism 29 to the center of the C-arm 25 may be set to 300 mm. In this way, when the robot side connection mechanism 18 is connected to the balancer side connection mechanism 29, the operating range of the handling of the balancer 20 can be expanded by the offset dimension of 300 mm compared to the case where there is no offset, and handling within the range of symbols a and b shown in Fig. 2 becomes possible. Note that the larger the offset dimension is than 300 mm, the more difficult it becomes to handle the robot arm and the balancer arm when handling near the robot, so the offset dimension is kept within 300 mm so as not to make the handling difficult. [Modification 3: Claim 5]

[0080] As shown in Fig. 7, instead of the connection mechanism support part 40 provided in the above embodiment, a connection mechanism support part 40C may be provided in which the offset dimension from the center of the balancer side connection mechanism 29 to the center of the C-arm 25 is variable. The connection mechanism support part 40C may have a horizontal guide 40d of a required length (e.g., 350 mm) protruding from the lower side surface of the C-arm 25 in a horizontally protruding state toward the robot hand 17, and a horizontally movable block 40e that is slidable on the horizontal guide 40d and fixed at an appropriate position by a bolt or the like, and the balancer side connection mechanism 29 is provided on the horizontally movable block 40e. This allows the offset dimension from the center of the balancer side connection mechanism 29 to the center of the C-arm 25 to be variable within the stroke range (300 mm) of the horizontally movable block 40e, and the forward handling range of the balancer 20 can be appropriately expanded within the range of the offset dimension, so that it can be adjusted to the periphery of the palletizing area at the site. [Modification 3: Claim 6]

[0081] As shown in Fig. 8, instead of the connection mechanism support part 40 provided in the above embodiment, a connection mechanism support part 40D whose support part is variable in the vertical direction may be provided. The connection mechanism support part 40D may have a vertical guide 40f having a required length (for example, 600 mm) provided on the side of the C-arm 25, and a lifting block 40g guided by the vertical guide 40f and fixed at an appropriate height position by a bolt or the like, and the balancer side connection mechanism 29 may be provided on the lifting block 40g. As a result, the connection height between the articulated robot 10 and the balancer 20 can be varied within a range of, for example, 500 mm offset in the vertical direction, so that the upper handling range of the balancer 20 can be expanded by 500 mm. [Modification 3: Claim 7]

[0082] 9, instead of the connection mechanism support part 40 provided in the above embodiment, a configuration may be adopted in which a lower balancer side connection mechanism 29 fixed to the lower end of the C-arm 25 and a second balancer side connection mechanism 29A provided to be able to freely move up and down from an upper position close to the lower balancer side connection mechanism 29 of the C-arm 25 to a position higher by a required dimension (for example, 500 mm) so as not to interfere with each other in a plan view may be provided. As a result, when the robot side connection mechanism 18 is connected to the lower balancer side connection mechanism 29, the connection height is fixed at a low position, and when the robot side connection mechanism 18 is connected to the upper second balancer side connection mechanism 29A, the connection height has a stroke of 500 mm from the low position to the high position, so that the heavy workpieces Wr can be stacked on the pallet P by switching between stacking up to 1 m and stacking up to 1.5 m. [Modification 3: Claim 10]

[0083] As shown in Fig. 10, in the above embodiment, instead of the table T1 shown in Fig. 1, a system configuration may be adopted in which a conveyor 71 for transporting small weight workpieces, a second conveyor 72 for transporting small weight workpieces, and a conveyor 73 for transporting heavy weight workpieces are disposed within the operating range of the vertical articulated robot 10. According to this configuration, the vertical articulated robot 10 performs handling by independently gripping a plurality of small weight workpieces Ws at the transport end on the conveyor 71 for transporting small weight workpieces and boxing them in the plastic case C on the conveyor 72 for transporting second small weight workpieces, which is repeated a required number of times, and the balancer 20 cooperates with the vertical articulated robot 10 to transport the heavy weight workpieces Ws that have been boxed by accommodating the required number of small weight workpieces Ws in the plastic case C at the transport end position on the conveyor 72 for transporting second small weight workpieces, onto the conveyor 73 for transporting heavy weight workpieces.

[0084] As described above, according to the work transport system of the present invention, the vertical articulated robot can handle small and heavy workpieces alone, and the balancer can handle small and heavy workpieces in cooperation with the vertical articulated robot, thereby improving the operability of the system.

[0085] Furthermore, according to the workpiece transport system of an embodiment of the present invention, the operational functions of the balancer when working in cooperation with the vertical articulated robot to perform handling can be expanded (the planar posture of the workpiece can be aligned by rotating the hand device, and the planar peripheral range of the balancer's handling can be expanded, as well as the handling height can be increased). [Explanation of symbols]

[0086] 1...Work transport system 10...Vertical articulated robot 11…Connecting plate 12...Rotating base 13…First arm 14…Second arm 15…Third arm 16…Robot wrist 16a...Flange 16b...Chuck jaws 17...Robot hand 17a...Flange 17b...Chuck jaws 18...Robot side connection mechanism 18a...Flange 18b...Chuck jaws 20…Balancer 21…Connecting plate 22...Rotating base 23…A-arm 24…B Arm 25…C-arm 25a...Top end 26…Balancer wrist 26a...Wrist rotation actuator 26A…Balancer wrist shaft support (fixed member without actuator and does not rotate) 27... Lifting balance mechanism 27a...Parallel link mechanism 27b...Air cylinder device 28...Hand device 29...Balancer side connection mechanism 29a...Flange 29A…Second balancer side connection mechanism 40...Connection mechanism support part 40a…Top horizontal part 40b…Lower end horizontal part 40c...Middle connection part 40A…Connection mechanism support part 40B...Connection mechanism support part 40d…Horizontal guide bar 40e…Slide block 40C...Connection mechanism support part 40D...Connection mechanism support part 40f…Up / Down guide 40g…Slide block 40E...Second connection mechanism support part 41...Air cylinder device (actuator) 51...Horizontal guide 52...Horizontal movable block 61...Up / Down guide 62…Lifting block 71...Conveyor for transporting small and heavy workpieces 72...Second small weight workpiece transport conveyor 73...Conveyor for transporting large and heavy workpieces 80…System installation stand 81…First fixed post 82…Second fixed post 83...Robot control unit 84...Balancer control section C…Plastic case P…Palette R1…First operating range R2: Second operating range T1…Table T2: Tool stand Ws: Small weight workpiece Wr...Heavy work

Claims

1. a vertical articulated robot having a robot hand attached to a robot wrist portion and handling a small, heavy workpiece that can be transported by the robot hand within a first operating range of a required size; a balancer having a multi-joint structure that is provided alongside the vertical articulated robot, the balancer having a C-arm that is supported at its upper end so as to be freely rotatable and that moves three-dimensionally at all times in a vertically hanging state, the lower end of the C-arm being a balancer wrist section to which a hand device is attached, and that maintains a stationary state by a lifting balance mechanism while the hand device is handling the light weight workpiece or before and after the hand device grasps the heavy weight workpiece that cannot be transported by a robot, and that handles the heavy weight workpiece within a second operating range of a required size that includes the first operating range in response to guidance of the vertical articulated robot connected to the C-arm, the robot wrist portion can chuck and unchuck a robot-side connection mechanism in place of the robot hand, and further, the robot-side connection mechanism chucked to the robot wrist portion can chuck and unchuck a balancer-side connection mechanism provided on a side of the balancer wrist portion, When handling the heavy workpiece, the robot wrist is equipped with the robot side connection mechanism and connected to the balancer side connection mechanism, the hand device attached to the balancer wrist grasps the heavy workpiece, and the balancer handles it according to the guidance of the vertical articulated robot. When handling the light workpiece, the robot side connection mechanism is detached from the balancer side connection mechanism, and the robot wrist detaches the robot side connection mechanism and attaches the robot hand, so that the vertical articulated robot handles it independently. A work transport system comprising:

2. 2. The work transport system according to claim 1, wherein the hand device provided at the lower end of the freely rotatable C-arm is provided coaxially with respect to the C-arm so as to be freely rotatable, and is adapted to rotate by a required angle relative to the C-arm in accordance with the posture of the work by a wrist rotation actuator attached to the C-arm.

3. 3. The work transport system as described in claim 1 or 2, characterized in that it comprises a connection mechanism support section consisting of an upper horizontal section guided along the C-arm to be able to stroke the required dimension in the vertical direction, a lower horizontal section extending in the direction of the robot wrist axis, and an intermediate connecting section connecting the upper horizontal section and the lower horizontal section together at a required distance, and an actuator attached to the C-arm, wherein the upper horizontal section is positioned at either a lowered position or an raised position by the actuator, and the center of the balancer side connection mechanism is offset by the required dimension from the center of the C-arm by providing the balancer side connection mechanism at the protruding end of the lower horizontal section.

4. 3. The work transport system according to claim 1 or 2, further comprising a horizontal extension bracket of a required length protruding horizontally from a lower side surface of the C-arm in the direction of the robot wrist axis, the balancer side connection mechanism being provided at the extension end of the horizontal extension bracket, and the center of the balancer side connection mechanism being offset from the center of the C-arm by a required dimension.

5. 3. The work transport system according to claim 1 or 2, further comprising: a horizontal guide of a required length protruding horizontally from a lower side surface of said C-arm in the direction of a robot wrist axis; and a horizontally movable block which is slidable on said horizontal guide and fixed at an appropriate position, said balancer side connection mechanism being provided on said horizontally movable block, and a center of said balancer side connection mechanism being offset in a variably dimensional manner from the center of said C-arm.

6. 3. The work transport system according to claim 1, further comprising a vertical guide attached to a side of the C-arm, and a lifting block guided by the vertical guide and fixed at an appropriate height position, the balancer side connection mechanism being provided on the lifting block.

7. 3. The workpiece transportation system according to claim 1, further comprising: a balancer side connection mechanism fixed to a lower end of the C-arm, instead of the connection mechanism support part; and a second balancer side connection mechanism arranged to be slidable up and down from an upper position close to the lower balancer side connection mechanism of the C-arm to a position higher by a required dimension, and positioned so as not to interfere with the lower balancer side connection mechanism in a plan view.

8. The work transport system described in claim 1 or 2, characterized in that the vertical articulated robot is installed on a first fixed post of a required height, the balancer is installed on a second fixed post that is higher than the first fixed post, and when the vertical articulated robot and the balancer work together to handle the heavy workpiece, multiple arms on the balancer side operate outside the multiple arms on the vertical articulated robot side so that the arms do not interfere with each other.

9. The work transport system described in claim 1 or 2, characterized in that it includes a table and a pallet, when the vertical articulated robot alone handles and boxes multiple small workpieces placed on the table in succession to form a boxed body of heavy workpieces, and further loads multiple large workpieces that have been boxed in succession on the table onto a pallet placed on the floor by the hand device of the balancer in succession.

10. 3. A work transport system according to claim 1, wherein a conveyor for transporting a small weight workpiece, a second conveyor for transporting a small weight workpiece and a conveyor for transporting a large weight workpiece are disposed within an operating range of said vertical articulated robot.

11. The work transport system described in claim 2, characterized in that when the robot side connection mechanism is connected to the balancer side connection mechanism and the balancer moves and handles based on the guidance of the articulated robot, the division of control between the balancer control unit and the vertical articulated robot control unit is such that the balancer control unit only controls the elevation angle of the A-arm which determines the height of the C-arm, and the vertical articulated robot control unit controls not only its own operation but also the extension and contraction operation of the actuator attached to the C-arm, the chucking operation of the hand device, and the rotation angle of the hand rotation drive means.

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