Industrial robot

Abstract

A spot welding robot including a base and an arm assembly mounted on the base. The arm assembly includes a lower arm mounted at a lower end on the base for a swingable movement about a substantially horizontal first axis, a swingable member mounted on the lower arm at an upper end portion of the lower arm for a swingable movement about a second axis which is parallel with the first axis, and an upper arm mounted at one end portion on the swingable member for a swingable movement about a third axis which is perpendicular to the second axis. The swingable member has a portion extending in a direction opposite to the direction in which the upper arm extends. A driving motor is provided on the swingable member for driving the upper arm to produce the swingable movement of the upper arm about the third axis.

We claim: 
     
       1. An industrial robot including a base, a lower arm mounted at a lower end on said base for a swingable movement about a substantially horizontal first axis, first motor means provided on said base for driving said lower arm to produce the swingable movement of said lower arm about said first axis, a swingable member mounted on said lower arm at an upper end portion of said lower arm for a swingable movement about a second axis which is parallel with said first axis, second motor means provided on said base for driving said swingable member to produce the swingable movement of said swingable member about said second axis, an upper arm mounted at one end portion on said swingable member for a swingable movement about a third axis which is perpendicular to said second axis, said upper arm projecting in one direction from said upper end portion of said lower arm and provided at the other end portion with a robot hand, said swingable member having a portion extending in a direction opposite to said one direction beyond said one end portion of said upper arm, third motor means.Iadd., .Iaddend.mounted on said portion of said swingable member .Iadd.and intersected by a plane defined by the swingable movement of said upper arm about said third axis, .Iaddend.for driving said upper arm to produce the swingable movement of said upper arm about said third axis. 
     
     
       2. The industrial robot of claim 1 in which said lower arm has a longitudinal axis and said horizontal first axis and said second axis are perpendicular to said longitudinal axis. 
     
     
       3. The industrial robot of claim 1 including a link extending generally parallel to said lower arm for interconnecting said swingable member and said second motor means. 
     
     
       4. The industrial robot of claim 1 in which said robot hand carries welding electrodes. 
     
     
       5. The industrial robot of claim 1 in which said robot hand is mounted for pivotal movement in relation to said upper arm. 
     
     
       6. The industrial robot of claim 1 in which said portion of the swingable member on which said third motor means is mounted is separate from said .[.swingable member.]. .Iadd.upper arm .Iaddend.and does not move when the upper arm is moved about said third axis. .Iadd. 
     
     
       7.  An industrial robot including a base, a lower arm mounted at a lower end on said base for a swingable movement about a substantially horizontal first axis, first motor means provided on said base for driving said lower arm to produce the swingable movement of said lower arm about said first axis, a swingable member mounted on said lower arm at an upper end portion of said lower arm for a swingable movement about a second axis which is parallel with said first axis, second motor means provided on said base for driving said swingable member to produce the swingable movement of said swingable member about said second axis, an upper arm mounted at one end portion on said swingable member for a swingable movement about a third axis which is perpendicular to said second axis, said upper arm projecting in one direction from said upper end portion of said lower arm and provided at the other end portion with a robot hand, said lower arm, said swingable member and said upper arm comprising an arm assembly, said arm assembly having a portion extending in a direction opposite to said one direction beyond said one end portion of said upper arm, third motor means, mounted on said portion of said arm assembly and intersected by a plane defined by the swingable movement of said upper arm about said third axis, for driving said upper arm to produce the swingable movement of said upper arm about said third axis. .Iaddend..Iadd. 
     
     
       8.  An industrial robot including: a base;   an arm assembly including a lower arm mounted at a lower end portion on said base for a swingable movement about a substantially horizontal first axis; a swingable member mounted on said lower arm at an upper end portion of said lower arm for a swingable movement about a second axis which is parallel with said first axis; and an upper arm mounted at a first end portion on said swingable member for a swingable movement about a third axis which is perpendicular to said second axis and provided at a second end portion with a robot hand, said upper arm projecting in one direction from said upper end portion of said lower arm;   first motor means for driving said lower arm to produce the swingable movement of said lower arm about said first axis;   second motor means for driving said swingable member to produce the swingable movement of said swingable member about said second axis; and   third motor means, mounted on a portion of said arm assembly and intersected by a plane defined by the swingable movement of said upper arm about said third axis, for driving said upper arm to produce the swingable movement of said upper arm about said third axis, at least a portion of said third motor means mounted on the arm assembly extending beyond said second axis in a direction opposite to said one direction. .Iaddend..Iadd.   
     
     
       9.  The industrial robot of claim 8, in which said second and third axes intersect. .Iaddend..Iadd.10. The industrial robot of claim 8, in which said third motor means for driving said upper arm about said third axis is mounted on a portion of said arm assembly situated above said lower arm. 
     
     
        .Iaddend..Iadd.11.  The industrial robot of claim 10, in which a longitudinal axis of said upper arm passes through said third motor means for driving said upper arm about said third axis. .Iaddend..Iadd.12. The industrial robot of claim 10, in which a longitudinal axis of said upper arm lies in a plane which passes through said third motor means for 
     
     
        driving said upper arm about said third axis. .Iaddend..Iadd.13.  The industrial robot of claim 8, in which said portion of the arm assembly, on which is mounted said third motor means for driving said upper arm, is fixed relative to said third axis, whereby the third motor means for driving said upper arm does not move with said upper arm about said third axis. .Iaddend..Iadd.14. An industrial robot including: a base;   an arm assembly including a lower arm mounted at a lower end portion on said base for a swingable movement about a substantially horizontal first axis; a swingable member mounted on said lower arm at an upper end portion of said lower arm for a swingable movement about a second axis which is parallel with said first axis; and an upper arm mounted at a first end portion on said swingable member for a swingable movement about a third axis which is perpendicular to said second axis and provided at a second end portion with a robot hand, said upper arm projecting in one direction from said upper end portion of said lower arm;   first motor means for driving said lower arm to produce the swingable movement of said lower arm about said first axis;   second motor means for driving said swingable member to produce the swingable movement of said swingable member about said second axis; and   third motor means, mounted on a portion of said arm assembly and intersected by a plane defined by the swingable movement of said upper arm about said third axis, for driving said upper arm to produce the swingable movement of said upper arm about said third axis, said third motor means for driving said upper arm being positioned with a center of gravity thereof located beyond the second axis in a direction opposite to said one direction. .Iaddend..Iadd.15. An industrial robot including:   a base;   an arm assembly including a lower arm mounted at a lower end portion on said base for a swingable movement about a substantially horizontal first axis; a swingable member mounted on said lower arm at an upper end portion of said lower arm for a swingable movement about a second axis which is perpendicular to a longitudinal axis of said lower arm; and an upper arm mounted at a first end portion on said swingable member for a swingable movement about a third axis which is perpendicular to said second axis, said upper arm projecting in one direction from said upper end portion of said lower arm;   first motor means for driving said lower arm to produce the swingable movement of said lower arm about said first axis;   second motor means for driving said swingable member to produce the swingable movement of said swingable member about said second axis; and   third motor means, mounted on a portion of said swingable member extending from said upper end portion of said lower arm in a direction opposite to said one direction, and intersected by a plane defined by the swingable movement of said upper arm about said third axis, for driving said upper arm to produce the swingable movement of said upper arm about said third   
     
     
        axis. .Iaddend..Iadd.16.  An industrial robot including: a base;   an arm assembly including a lower arm mounted at a lower end portion on said base for a swingable movement about a substantially horizontal first axis, and an upper arm assembly situated above the lower arm for a swingable movement about a second axis which is spaced from and parallel with said first axis, the upper arm assembly comprising a first portion extending in one direction beyond the lower arm and a second portion extending in a direction opposite to said one direction beyond the lower arm, said first portion being mounted for a swingable movement about a third axis which is perpendicular to said second axis;   first motor means for driving said lower arm to produce the swingable movement of said lower arm about said first axis;   second motor means for driving said upper arm assembly to produce the swingable movement of said upper arm assembly about said second axis; and   third motor means, mounted on said second portion of said upper arm assembly and intersected by a plane defined by the swingable movement of said first portion of the upper arm assembly about said third axis, for driving said first portion of the upper arm assembly to produce the swingable movement of said first portion of the upper arm assembly about   
     
     
        said third axis. .Iaddend..Iadd.17.  The industrial robot of claim 16, in which said second portion of the upper arm assembly, on which is mounted said third motor means for driving said first portion of the upper arm assembly, is fixed relative to said third axis, whereby the third motor means for driving said first portion of the upper arm assembly does not move with said first portion about said third axis. .Iaddend..Iadd.18. An industrial robot including: a base;   a lower arm mounted at a lower end portion on said base, and first motor means for swinging the lower arm about a first substantially horizontal axis;   an arm assembly above said lower arm including a swingable member mounted on an upper end portion of said lower arm for a swingable movement about a second axis which is parallel with said first axis, and an upper arm mounted at one end portion on said swingable member, said upper arm having a longitudinal axis disposed above the upper end portion of said lower arm, and having a robot hand at an opposite end portion thereof;   second motor means for swinging said swingable member about said second axis; and   third motor means mounted on said arm assembly at said one end portion of said upper arm for swinging said upper arm about a third axis which is perpendicular to said second axis, said third motor means being intersected by a plane defined by the swinging of said upper arm about   
     
     
        said third axis. .Iaddend..Iadd.19.  The industrial robot of claim 18, wherein the second and third axes intersect. .Iaddend.