FITTING STRUCTURE OF HORIZONTAL MULTIPLE JOINT ROBOT ARMS

Abstract: This invention relates to a structure for fitting a robot base (1) with a first arm (3) of a horizontal multiple joint type robot. The base (2) of the first arm is fitted rotatably to a slider (6), which is guided linearly in the longitudinal direction of the robot base, and the rotation of the slider and the base is restricted by removable fixing means. The present invention is effective for packaging a robot.

Description: The present invention is directed to an improved arm fitting structure of a horizontal articulated robot, to realize a desired packaging of the robot, and is particularly effective for a large horizontal articulated robot. As shown in Figs. 7A and 7B of the accompanying drawings, a conventional horizontal articulated robot comprises a robot base 1 along which a slider 6' moves vertically, and a base 2' located at a base end of a first arm 3' is fixed to the slider 6'. For packaging, a stopper S₁ is arranged between the base 2' and the first arm 3', and the first arm is horizontally folded. Also a stopper S₂ is disposed between the first arm and a second arm 4, and the second arm 4 is horizontally folded. Then, while ensuring that the second arm 4 does not touch the robot base 1, the arms are folded to reduce the robot to as small a shape as possible. Therefore, as apparent from Fig. 7B, when folding the arms for packaging, the first arm 3' with an arm length L₃ is pivoted and folded around a point O₃ on the base 2', and the second arm 4 with an arm length L₄ is pivoted and folded around a journal point O₄ on the first arm. therefore, no matter how the arms 3 and 4 are folded, a shape thereof as seen from the top of the robot will have large projections due to the arm lengths L₃ and L₄. EP-A-0160951 discloses an arm fitting structure of an articulated robot, comprising a vertical robot base, a linearly movable slider guided longitudinally along said robot base up to an upper portion thereof, an arm base fitted to the slider, a first arm extending horizontally from the arm base and being pivotable relative to the arm base about a first axis, and a second arm being pivotable relative to the first arm about a second axis parallel to the first axis, and, according to the invention, such a structure is characterised in that the vertical robot base has a length at least equal to the combined length of said first and second arms when they are linearly extended, in that the arm base is rotatable relative to the slider about a third axis perpendicular both to the longitudinal direction of the vertical robot base and to the first and second axes, and in that it comprises removable stopping means for restricting the rotation of the arm base relative to the slider. Upon packaging, as shown in Figs. 5 and 6 of the accompanying drawings, the slider 6 is raised, and fastening bolts B₁ forming the stopping means are removed so that the base 2 can freely rotate relative to the slider 6. Then by rotating the base 2, the whole of the arm is turned by 90° on the surface of the slider 6, and the whole arm is folded vertically along the robot base 1. Accordingly, the whole robot can be folded to a compact size and shape, with the whole of the arm hung down along a vertical axis so that the package volume is further reduced. Since the structure fitting the arm to the slider is rotatable, the arm may be set to an optimum configuration for robot operation and packaging. In the accompanying drawings: Fig. 1 is a perspective view showing essential parts of the present invention; Fig. 2 is a sectional view taken along a line Y-Y of Fig. 1; Fig. 3 is an exploded perspective view showing a base fitting portion of a robot arm of the present invention; Fig. 4 is a general perspective view showing an operative state of the robot of the present invention; Fig. 5 is a view showing a rotational state of a base portion of Fig. 2; Fig. 6 is a general perspective view showing a packaging state of the robot of the present invention; Fig. 7A is a general perspective view showing a packaging state of a robot according to a prior art; and Fig. 7B is a top view of Fig. 7A. As schematically shown in Fig. 4, a base 2 of an arm is fitted to a robot base 1 (an axis Z) through a slider, in such a manner that the base 2 is controlled and moved vertically. The base 2 is provided with a first arm 3, and this first arm 3 is horizontally controlled and rotated by a motor M₁. A second arm 4 is fitted to a front end of the first arm 3, through a motor M₂ , in such a manner than the second arm 4 can be horizontally controlled and rotated. A wrist 5 is controllably and operably fitted to a front end of the second arm 4 through a motor M₃. The horizontal articulated robot thus formed is known, and the present invention is intended to improve a structure for fitting the first arm 3. Namely, as shown in Figs. 1, 2 and 3, the slider 6 comprises a fitting base plate 60 from which a square pipe portion 61 protrudes, and a square pipe front end plate 62 thereof is provided with a central engaging hole 63. Reference h₂ represents a screw hole. The base 2 comprises a square pipe 21 for supporting the first arm 3, a flange 22 to be fitted to the slider front end plate 62, and an engaging cylinder 23 protruding from the flange 22; these components being formed integrally as one body. The flange 22 is provided with four bolt holes h₁ , and a front end of the engaging cylinder 23 is provided with four screw holes (not shown) at equidistant intervals. Numeral 7 denotes a circular plate having a diameter larger than that of the engaging hole 63. The circular plate 7 is provided with four bolt holes h₃ matching the screw holes formed at the front end of the engaging cylinder 23. Upon assembly, the engaging cylinder 23 of the base 2 is inserted into the engaging hole 63 from the front end plate 62 side of the slider 6, and the plate 7 is attached to the front end of the engaging cylinder 23 inside the square pipe portion 61 of the slider 6, by bolts B₂ passed through the bolt holes h₃ from the plate 7 side and screwed into the screw holes formed on the front end of the cylinder 23. Bolts B₁ are passed through the bolt holes h₁ of the flange of the base 2 and screwed into the screw holes h₂ of the front end plate 62 of the slider 6. The first arm 3 is fitted to the base 2 and the slider 6 is fitted to the robot base 1 through an LM guide (a linear motion guiding apparatus) LMG comprising a guide piece 11 and rails 10, by known techniques. A large horizontal articulated robot with the first arm fitting structure shown in Figs. 1, 2 and 4 can perform a set control operation in the same way as a conventional robot, without problems. When packaging the thus-obtained robot, the slider 6 is raised, and the bolts B₁ are removed as shown in Fig. 5 to release the flange 22 of the base 2 from the slider front end plate 62. While preventing a detaching of the base 2 from escaping from the slider 6, the plate 7 is slid on an inner surface of the slider front end plate 62 and the flange 22 is slid on an outer surface of the slider front end plate 62, so that the base can be turned by twisting the first arm 3. The first arm 3 is twisted by 90°, and is vertically folded around a shaft 31 as shown in Fig. 6. As apparent from Fig. 6, in a packaging configuration, all of the arms hang down along the robot base 1, thus remarkably reducing the packaging volume compared with a conventional configuration (refer to Figs. 7A and 7B) and greatly reducing packaging and transporting costs. As the means for restricting the rotation of the base 2 relative to the slider 6, the bolts B₁ mentioned above can be replaced by, for example, a fixing plate (not shown) attached to the base and slider from the outside and fixed by fastening bolts (not shown). Alternatively, the square pipe portion 61 of the slider 6 is provided with a cylindrical surface portion and folded projections of the flange portion 22 of the base 2 extend over the cylindrical surface portion, and then the folded projections and cylindrical surface portion are removably fixed to each other by fastening bolts. It is clear that the object of the present invention is also achieved with this arrangement. According to the embodiment, the base 2 can rotate around an axis perpendicular to a plane of the slider 6, and thus the base 2 is rotated from an initial stop position shown in Fig. 1 around the above-mentioned axis by 90° and then stopped with respect to the slider 6. Namely, as shown in Fig. 3, the bolt holes h₁ and screw holes h₂ are disposed at regular angles on a circle having a predetermined radius around an axis perpendicular to the plane of the slider 6. When packaging, as shown in Fig. 6, the base 2 is rotated by 90° and fixed by the bolts B₁ , to advantageously stop the rotation thereof.

Claims: An arm fitting structure of an articulated robot, comprising a vertical robot base (1), a linearly movable slider (6) guided longitudinally along said robot base (1) up to an upper portion thereof, an arm base (2) fitted to the slider, a first arm (3) extending horizontally from the arm base (2) and being pivotable relative to the arm base (2) about a first axis, and a second arm (4) being pivotable relative to the first arm (3) about a second axis parallel to the first axis, characterised in that the vertical robot base (1) has a length at least equal to the combined length of said first (3) and second arms (4) when they are linearly extended, in that the arm base (2) is rotatable relative to the slider about a third axis perpendicular both to the longitudinal direction of the vertical robot base (1) and to the first and second axes, and in that it comprises removable stopping means (B₁) for restricting the rotation of the arm base (2) relative to the slider (6). An arm fitting structure according to claim 1, wherein the arm base (2) is rotationally fixed to the slider (6) by screw bolts (B₁) such that when said screw bolts are loosened, the base (2) can rotate relative to the slider (6), but can not separate therefrom, due to a plate (7). An arm fitting structure according to claim 2, wherein the arm base (2) can be rotated relative to the slider (6) around the first axis by 90° from an initial stop position to a second stop position in which it can be fixed.

Inventors: ITO SUSUMU FANUC MANSION HARIM, TANAKA AKIRA FANUC DAI- VIRA-K, TORII NOBUTOSHI, ITO, SUSUMU FANUC MANSION HARIMOMI 7-204, TANAKA, AKIRA FANUC DAI-3 VIRA-KARAMATSU, TORII, NOBUTOSHI
Applicants: FANUC LTD, FANUC LTD.
Application year: 1989
Main classification: B25J9
IPC codes: B25J18, B25J9