Abstract:
A plurality of clamp devices for clamping a cable or a pipe connected to an end effector of a robot are mounted to a robot wrist portion. A first clamp device has a base and a clamp portion configured to slide linearly with respect to the base and be also capable of turning about an axis perpendicular to the slide direction. A second clamp device has a base and a clamp portion configured to be capable of turning about an axis perpendicular to the installation surface of the base. A third clamp device has a revolving unit fitted to the circumference of the arm and configured to be capable of pivotal motion in the circumferential direction of the arm and a clamp portion provided on the circumference of the revolving unit to be capable of turning about an axis in the radial direction of the revolving unit. The clamp portions of these clamp devices are adapted to clamp the cable or the pipe extending to the end effector.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an industrial robot, and more particularly, to a guide device for guiding a pipe or a cable connected to an end effector at the tip of a robot wrist. 
     2. Description of the Prior Art 
     Generally, in an industrial robot, an end effector suitable for various jobs is mounted to a wrist at the tip of an arm, and a piping member or a wiring member for supply of power and liquid and supply and exhaust of air is connected to the end effector. 
     FIG. 7 shows the configuration of a six-axis robot as one of industrial robots. The six-axis robot fixed to an installation surface as shown in FIG. 7 is capable of turning by turning axes J 1  to J 6  at turning angles of θ, W, U, γ, β and α. This robot has a wrist  20  at the tip of an arm  10 , and an end effector is mounted to the wrist  20 . 
     In the prior art, taps or holes provided in required portions of the robot body for installation of the equipment are used for installation of a cable or like wiring member or a pipe or like piping member connected to the end effector. 
     FIG. 8A illustrates the installation of the piping member or the wiring member in the prior art. In FIG. 8A, there is shown the state of the piping member or the wiring member attached to the arm and the wrist at the tip of the arm. The wrist  20  has turning axes  21 ,  22  and  23  connected together, and these turning axes are different from one another in axial direction of turning. An end effector  5  is mounted to one end of the wrist  20  so that it can turn about the turning axis  23  and also can be exchanged. Further, the other end of the wrist  20  is mounted to the arm  10  through the turning axis  21  so that the wrist  20  can turn. 
     The installation of the piping member or the wiring member is made by means of supporting its intermediate portion with a clamp portion  9  fixed to the arm  10 , while holding its end portion in place to a clamp portion  6  fixed to the end effector  5 . 
     According to the installation of the piping member or the wiring member in the prior art, there is a problem in that the wiring member and/or the piping member makes contact with a robot itself or its peripheral equipment to cause wear of the wiring member and/or the piping member, resulting in a need for periodical maintenance. 
     Generally, when the turning axes of the wrist portion are actuated for wrist motion, the wiring member and/or the piping member moves flexibly with respect to the arm according to the wrist motion. However, in case of a wiring member and/or a piping member of insufficient length, it is not possible to cope with the above flexible motion, resulting in hindrance from carrying out the wrist motion. In this connection, the prior art is configured to meet the flexible motion of the wiring member and/or the piping member by slackening the wiring member and/or the piping member ranging from the arm to the end effector. FIG. 8A shows the installation of the wiring member and/or the piping member slackened. 
     However, when each turning axis is turned for the wrist motion, the slack of the wiring member and/or the piping member causes contact of the wiring member and/or the piping member with the robot itself or its peripheral equipment. Further, it is feared that the wiring member and/or the piping member gets twisted round the wrist portion to hinder from carrying out the wrist motion, depending on the past motions of the wrist. 
     Further, the slack of the wiring member and/or the piping member has to be adjusted for each and every robot. Thus, much time is required for the installation of the wiring member and/or the piping member, which is a problem. 
     FIG. 8B shows how, during one motion, in which turning of the turning axes  21  and  23  causes contact of the slack portion of the wiring member and/or the piping member with the wrist portion, the wiring and/or the piping member can be damaged. 
     OBJECT AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to prevent a wiring member and/or a piping member from interfering with a robot itself or its peripheral equipment. 
     The present invention relates to a device for guiding a wiring member and/or a piping member connected to an end effector at the tip of a robot wrist via a robot arm. This guide device is adapted to attach a cord-shaped body such as a wiring member and a piping member to a robot, more particularly, to an arm and a wrist portion. The cord-shaped body may include only a wiring member or a piping member, or a bundle of both the wiring member and the piping member, or a body formed by housing the wiring member and the piping member in one pipe. Further, each wiring member or piping member may be configured in a bundle of wiring members or piping members or a body formed by housing the wiring members or the piping members in one pipe, without being limited to a single wiring member or a single piping member. 
     The guide device for the wiring member and/or the piping member according to the present invention comprises a clamp device having a support portion and a clamp portion capable of loose motion with respect to the support portion and adapted to clamp the wiring member and/or the piping member. In mounting the clamp device to the robot, the support portion is disposed on a robot portion, and the direction of loose motion of the clamp portion is placed to cross the drive axis direction of the robot portion, on which the support portion is disposed. 
     Arrangement of the guide device of the present invention is determined such that the direction of loose motion of the clamp portion and the drive axis direction of the robot portion, on which the support portion is disposed, may cross each other in mounting the clamp device to the robot portion. With the above configuration, when the wiring member and/or the piping member expand and contract with respect to the arm, the loose motion of the clamp portion occurs. The loose motion of the clamp portion makes it possible to displace the wiring member and/or the piping member according to the wrist motion without making contact with the robot or its peripheral equipment. Thanks to the displacement of the wiring member and/or the piping member, the robot may perform a smooth wrist motion. 
     The robot portion, on which the support portion is disposed, may be an arm, a turning portion or the like, and the loose motion of the clamp portion may include a translation motion and a turning motion. The guide device of the present invention may take various modes on the basis of the robot portion and the state of loose motion. Incidentally, cross angle between the direction of loose motion of the clamp portion and the drive axis direction of the robot portion can be of any degrees, without being limited to right angle. With this cross angle, force applied to the wiring member and/or the piping member as the result of its flexible motion is decomposed into components in the directions of loose motion of the clamp portion, causing the clamp portion to move loosely. Consequently, the wiring member and/or the piping member is prevented from interfering with the robot or its peripheral equipment. 
     In the first mode of the present invention, a mounting portion of the clamp device is set on the arm side, a base is adapted for the support portion, and the clamp portion to clamp the wiring member and/or the piping member is configured to be guided in a linear direction with respect to the base and is also capable of turning about an axis perpendicular to the slide direction. Then, the base is disposed on the arm with the slide direction of the clamp portion substantially aligned with the longitudinal direction of the arm. 
     According to the first mode of the present invention, flexible motion of the wiring member and/or the piping member cause the clamp portion to slide and turn with respect to the arm so that the wiring member and/or the piping member are displaced to a position free from interference with the robot and its peripheral equipment according to the wrist motion. Thus, the wiring member and/or the piping member can be prevented from interfering with the robot and its peripheral equipment, permitting a smooth wrist motion. 
     In the second mode of the present invention, a mounting portion of the clamp device is set on the arm side, a revolving unit capable of loose motion along the circumference is adapted for the support portion, and the clamp portion to clamp the wiring member and/or the piping member is configured to be capable of turning about an axis which connects the revolving center of the revolving unit and the clamp portion. Then, the clamp portion is placed on the arm with the revolving unit disposed on the circumference of the arm. 
     According to the second mode of the present invention, flexible motion of the wiring member and/or the piping member cause the clamp portion to revolve and turn with respect to the arm so that the wiring member and/or the piping member are displaced to a position free from interference with the robot and its peripheral equipment according to the wrist motion. Thus, the wiring member and/or the piping member can be prevented from interfering with the robot and its peripheral equipment, permitting a smooth wrist motion. 
     In the third mode of the present invention, a mounting portion of the clamp device is set on the wrist side, a base is adapted for the support portion, and the clamp portion to clamp the wiring member and/or the piping member is configured to be capable of turning about an axis perpendicular to the installation surface of the base. Then, the clamp portion is placed on the wrist or a wrist casing such that the turning axis of the clamp portion may be aligned with or in parallel to the swing axis of the wrist. 
     According to the third mode of the present invention, flexible motion of the wiring member and/or the piping member cause the clamp portion to turn with respect to the wrist so that the wiring member and/or the piping member are displaced to a position free from interference with the robot and its peripheral equipment according to the wrist motion. Thus, the piping member and/or the wiring member can be prevented from interfering with the robot and its peripheral equipment, permitting a smooth wrist motion. 
     In the fourth mode of the present invention, a mounting portion of the clamp device is set on the arm side, a movable unit capable of revolution and sliding along a cylindrical surface is adapted for the support portion, and the clamp portion to clamp the wiring member and/or the piping member is configured to be capable of turning about an axis which connects the revolving center of the movable unit and the clamp portion. Then, the clamp portion is placed on the arm with the movable unit disposed on the circumference of the arm. 
     According to the fourth mode of the present invention, flexible motion of the wiring member and/or the piping member cause the clamp portion to revolve, slide and turn with respect to the arm so that the wiring member and/or the piping member are displaced to a position free from interference with the robot and its peripheral equipment according to the wrist motion. Thus, the wiring member and/or the piping member can be prevented from interfering with the robot and its peripheral equipment, permitting a smooth wrist motion. 
     Further, the present invention involves a robot having the above guide device. The robot of the present invention includes a robot comprising the guide device according to at least one of the first to fourth modes described above, or may also include a robot, to which a combination of the above modes or all the above modes are applied. 
     Incidentally, in the guide device of the present invention, the wiring member and/or the piping member can be attached to the translation axis or the turning axis of the robot without being limited to the arm and the wrist portion. 
     According to the present invention, the wear caused by contact of the wiring member and/or the piping member with the robot itself and its peripheral equipment can be reduced by preventing the wiring member and/or the piping member from interfering with the robot itself and its peripheral equipment, allowing maintenance operations of the robot and the wiring member and/or the piping member to reduce. Further, the life of the robot and the wiring member and/or the piping member can be extended, permitting less running cost. 
     Furthermore, the time taken for the installation of the wiring member and/or the piping member can be reduced, permitting less cost required for alteration of a system including the robot. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects and features of the invention will become apparent from the following description of preferred embodiments of the invention with reference to the accompanying drawings, in which: 
     FIGS. 1A and 1B are views respectively showing the first embodiment of a guide device according to the present invention when applied to a wrist portion of a robot; 
     FIGS. 2A to  2 C illustrate respectively the first embodiment of a clamp device for use in the guide device of FIG.  1 A: 
     FIGS. 3A and 3B illustrate respectively the second embodiment of a clamp device for use in the guide device of FIG.  1 A: 
     FIGS. 4A to  4 C illustrate respectively the third embodiment of a clamp device for use in the guide device of FIG. 1A; 
     FIGS. 5A and 5B are views showing respectively the second embodiment of a guide device according to the present invention when applied to a wrist portion of a robot; 
     FIGS. 6A and 6B illustrate respectively the fourth embodiment of a clamp device for use in the guide device of FIG. 5A; 
     FIG. 7 is a view showing an industrial robot in the prior art; and 
     FIG. 8 illustrates the posture of a wiring member or a piping member connected to an end effector of a robot. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A robot having a guide device according to the present invention may be applied to an industrial robot. An industrial robot having six axes, for instance, may have the configuration as shown in FIG.  7 . In the robot shown, arms actuated for turning or translation motion with a plurality of turning axes or translation axes are connected to a robot body fixed to an installation surface. An end effector may be mounted to a wrist  20  at the tip of the arm  10  so that it can be exchanged. 
     FIG. 1A shows the first embodiment of a guide device according to the present invention when applied to a wrist portion of the robot. 
     In FIG. 1A, the arm  10  has a wrist  20  mounted at the tip and having a plurality of turning axes. The wrist  20  has a first turning axis  21 , a second turning axis  22  and a third turning axis  23  mounted in this order from the side of the arm  10 , and the end effector  5  is mounted to the third turning axis  23  so that it can be exchanged. Incidentally, the first turning axis  21  and the second turning axis  22  and also the second turning axis  22  and the third turning axis  23  are placed respectively to cross axially each other at right angles. 
     The wrist  20  makes a swing motion according to a swing angle of the second turning axis  22 . 
     The guide device shown in FIG. 1A comprises a first guide device  1 , a second guide device  2  and a third guide device  3 . These guide devices support the wiring member and/or the piping member  4  attached to the end effector  5  mounted at the tip of the wrist  20 , and are also adapted to guide the wiring member and/or the piping member by varying the relation between the position of the wiring member and/or the piping member and that of each guide device according to the wrist motion. 
     The first guide device  1  has a base  1   a  also serving as a sliding unit and a turning clamp portion  1   b  and is placed on the arm  10 . The second guide device  2  has a revolving unit  2   a  and a turning clamp portion  2   b  and is placed adjacent to the first turning axis  21  in the neighborhood of the wrist  20  of the arm  10 . The third guide device  3  has a base  3   a  and a turning clamp portion  3   b  and is placed on the third turning axis  23 . 
     The wiring member and/or the piping member  4  is clamped and is also supported as being capable of loose motion by the respective clamp portions of the first guide device  1 , the second guide device  2  and the third guide device  3 . The tip portion of the wiring member and/or the piping member is supported with the clamp portion  6  of the end effector  5  as being fixed in place. With the above configuration, the wiring member and/or the piping member can be displaced in association with the loose motion including the turning motion and the translation motion of each guide portion according to the wrist motion. 
     FIG.1B shows the state, in which the first turning axis  21 , the second turning axis  22  and the third turning axis  23  in the wrist portion of the robot shown in FIG. 1A are turned respectively in a direction a, a direction b and a direction c. 
     When each turning axis of the wrist  20  is turned, the respective clamp portions of the first guide device  1 , the second guide device  2  and the third guide device  3  turn or perform the translation motion. As a result, the wiring member and/or the piping member  4  is held in place in a stable state without getting twisted round the arm  10  or the wrist  20 . A description will now be given of the first guide device  1 , the second guide device  2  and the third guide device  3  with reference to FIGS. 2A to  4 C. 
     The first guide device  1  has the base  1   a  and the turning clamp portion  1   b , as shown in FIG.  2 A. The base  1   a  also serves as the sliding unit, which causes the turning clamp portion  1   b  to perform the translation motion. A guide such as a groove  1   d  formed in the base  1   a , for instance, may be applied to perform the translation motion of the turning clamp portion. The turning clamp portion  1   b  is adapted to clamp the wiring member and/or the piping member  4  and is also configured to turn about an axis  1   f . In the turning clamp portion  1   b , the translation motion along the groove  1   d  and the turning motion about the axis  1   f  are caused by force applied from the wiring member and/or the piping member  4  clamped by the turning clamp portion  1   b.    
     The direction of the axis  1   f  of the turning clamp portion  1   b  is configured to cross the direction of translation motion of the sliding unit at substantially right angles. With the above configuration, the force applied from the piping member  4  is decomposed into components in the directions of translation motion and turning, permitting a smooth displacement of the wiring member and/or the piping member  4 . 
     FIG. 2B shows the state, in which the turning clamp portion  1   b  of FIG. 2A performs the translation motion in the direction shown by an arrow A, and is also turned in the direction shown by an arrow B. In contrast with the case shown in FIG. 2B, FIGS. 2C shows the state, in which the turning clamp portion  1   b  of FIG. 2A performs the translation motion in the direction shown by an arrow A, and is also turned in the direction shown by an arrow B′ (a direction opposite to the direction shown by the arrow B). 
     The second guide device  2  has the revolving unit  2   a  and the turning clamp portion  2   b , as shown in FIG.  3 A. The revolving unit  2   a  is adapted to turn the turning clamp portion  2   b  along the circumference of the arm  10 . A bearing mechanism  2   c  provided on the revolving unit  2   a , for instance, may be applied to perform the turning motion of the turning clamp portion. The turning clamp portion  2   b  is adapted to clamp the wiring member and/or the piping member  4  and is also configured to turn about an axis  2   f . The turning motion of the revolving unit  2   a  and that of the turning clamp portion  2   b  are caused by force applied from the wiring member and/or the piping member  4  clamped by the turning clamp portion  2   b.    
     An axis  2   g  of the revolving unit  2   a  crosses the axis  2   f  of the turning clamp portion  2   b  at substantially right angles. With the above configuration, the force applied from the piping member  4  may be decomposed into components in the turning directions of the revolving unit  2   a  and the turning clamp portion  2   b , permitting a smooth displacement of the wiring member and/or the piping member  4 . 
     FIG. 3B shows the state, in which the revolving unit  2   a  of FIG. 3A revolves in the direction shown by an arrow C and the turning clamp portion  2   b  is turned in the direction shown by an arrow D. 
     The third guide device  3  has the base  3   a  and the turning clamp portion  3   b , as shown in FIG.  4 A. The base  3   a  is fixed to the wrist or a wrist casing  7  to support the turning clamp portion  3   b  as being capable of turning. The turning clamp portion  3   b  is adapted to clamp the wiring member and/or the piping member  4  and is also configured to turn about an axis  3   f . The turning motion of the turning clamp portion  3   b  is caused by force applied from the wiring member and/or the piping member  4  clamped by the turning clamp portion  3   b.    
     The axis  3   f  of the turning clamp portion  3   b  is placed to cross the surface of the second turning axis  22  of the wrist  20  of the robot at substantially right angles such that the axis  3   f  may be aligned with or in parallel to the axis  22   f  of the second turning axis  22 . With the above configuration, the force applied from the piping member  4  may be decomposed into components in the turning directions of the turning clamp portion  3   b , permitting a smooth displacement of the wiring member and/or the piping member  4 . 
     FIG. 4B shows the state, in which the second turning axis  22  of FIG. 4A has been pivoted about the axis  22   f  in the direction shown by an arrow b. FIG. 4C shows the state, in which the turning clamp portion  3   b  has been pivoted about the axis  3   f  in the direction shown by an arrow E according to the pivotal motion of the second turning axis  22 . 
     FIG. 5A shows the second embodiment of a guide device according to the present invention when applied to the wrist portion of the robot. The second embodiment is different from the first embodiment of FIG. 1A in that a fourth guide device is used instead of the first guide device  1 . That is, the guide device of FIG. 5A comprises the second guide device, the third guide device and the fourth guide device. 
     The second guide device  2  has the revolving unit  2   a  and the turning clamp portion  2   b  and is placed adjacent to the first turning axis  21  in the neighborhood of the wrist  20  of the arm  10 . 
     The third guide device  3  has the base  3   a  and the turning clamp portion  3   b  and is placed on the third turning axis  23 . 
     The fourth guide device  8  has a movable unit  8   a  and a turning clamp portion  8   b  and is placed on the arm  10 . 
     The wiring member and/or the piping member  4  is clamped and is also supported by the respective clamp portions of the fourth guide device  8 , the second guide device  2  and the third guide device  3  in a manner such that it can move loosely. The tip portion of the wiring member and/or the piping member is fixedly supported with the clamp portion  6  of the end effector  5 . With the above configuration, the wiring member and/or the piping member can be displaced in association with the loose motion including the turning motion and the translation motion of each guide portion according to the wrist motion. 
     FIG. 5B shows the state, in which the first turning axis  21 , the second turning axis  22  and the third turning axis  23  in the wrist portion of the robot shown in FIG. 5A has been turned in the direction a, the direction b and the direction c, respectively. When each turning axis of the wrist  20  is turned, the respective clamp portions of the fourth guide device  8 , the second guide device  2  and the third guide device  3  turn (in the directions shown by arrows C, D, E, F and H in the drawing) or perform the translation motion (in the direction shown by an arrow G in the drawing). As a result, the wiring member and/or the piping member is held in place in a stable state without getting twisted round the arm  10  or the wrist  20 . 
     The fourth guide device  8 . has the movable unit  8   a  and the turning clamp portion  8   b , as shown in FIG.  6 A. The movable unit  8   a  is adapted to cause the turning claim portion  8   b  to turn along the circumference (shown by an arrow F in the drawing) of the arm  10  and also to slind in the longitudinal direction (shown by an arrow G in the drawing) of the arm  10 . Balls  11  provided in the movable unit  8   a , for instance, are rolled on the cylindrical surface of the arm  10  to perform the turning and slide motions of the turning clamp portion  8   b.    
     The turning clamp portion  8   b  is adapted to clamp the wiring member and/or the piping member  4  and is also configured to turn about an axis (as indicated by an arrow H in the drawing). The turning motions of the movable unit  8   a  and the turning clamp portion  8   b  and the slide motion of the movable unit  8   a  are caused by force applied from the wiring member and/or the piping member  4  clamped by the turning clamp portion  8   b.    
     The axis of the movable unit  8   a  and that of the turning clamp portion  8   b  are placed to cross each other at substantially right angles. With the above configuration, the force applied from the wiring member and/or the piping member  4  is decomposed into components in the turning directions of the movable unit  8   a  and the turning clamp portion  8   b  and in the direction of the translation motion of the movable unit  8   a , permitting a smooth displacement of the wiring member and/or the piping member  4 . 
     FIG. 6B shows the state, in which the movable unit  8   a  revolves in the direction shown by the arrow F and also slides in the direction shown by the arrow G, and the turning clamp portion  8   b  is turned in the direction shown by the arrow H. 
     As has been described in the foregoing, according to the present invention, it is possible to prevent the wiring member and/or the piping member from interfering with the robot itself or its peripheral equipment.