Electricity: motive power systems – Positional servo systems – Program- or pattern-controlled systems
Reexamination Certificate
1999-12-07
2001-09-04
Dang, Khanh (Department: 2837)
Electricity: motive power systems
Positional servo systems
Program- or pattern-controlled systems
C901S016000
Reexamination Certificate
active
06285152
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an industrial robot having a direct-acting mechanism.
BACKGROUND ART
A horizontal multi-joint type pelletizing robot shall be described with reference to the drawings.
FIG. 2
is a sectional side view showing a prior-art horizontal multi-joint type pelletizing robot, which represents a mechanism of a horizontal or vertical acting shaft of a prior-art industrial robot having a direct-acting mechanism in the horizontal and vertical direction.
The supporting frame
1
has a rectangular parallelepiped box-shaped structure, in which the front face is opened, and which comprises top plate
11
, back plate
12
, bottom plate
13
, two unillustrated side plates, and middle plate
14
whose three sides are fixed to the top plate
11
and both side plates are disposed inside. The upper surface of the top plate
11
, the lower surface of the bottom plate
13
, and the front surface of the middle plate
14
are machined so as to be parallel or vertical to each other. At the bottom plate
13
, fitting hole
15
is machined by being centered on the basis of the machined surface of the middle plate
14
.
A direct-acting guide,
2
is fixed at the machined surface of the front surface of the middle plate
14
. A power transmission device
4
such as a gear box, which has a convex part
41
precisely processed at the lower surface. The power transmission device
4
is positioned within a horizontal plane by fitting the convex part
41
into the fitting hole
15
, and furthermore, positioned so as to be at a predetermined position and have a predetermined posture with respect to the direct-acting guide
2
by adjusting an unillustrated positioning tool, and fixed at the bottom plate
13
. A motor,
5
is fixed to the power transmission mechanism
4
, and an unillustrated drive shaft of the motor
5
is coupled with the power transmission device
4
. A feed screw
6
comprised of a screw body
61
, a nut part
62
, an upper bearing
63
, and a lower bearing
64
.
At the lower end part of the screw body
61
, an unillustrated spline is formed, which is engaged with an unillustrated gear of the power transmission device
4
. The lower bearing
64
is fixed to the power transmission device
4
, and the upper bearing
63
is fixed to the machined surface of the upper surface of the top plate
11
. The feed screw
6
is parallel to the direct-acting guide
2
, and is adjusted and positioned at a predetermined space. An arm supporting slider
7
is slidably supported by the direct-acting guide
2
, and fixed to the nut part
62
. The arm supporting slider
7
is driven by the motor
5
via the power transmission device
4
and feed screw
6
to vertically move along the direct-acting guide
2
.
An arm part
8
is comprised of a first arm
81
, second arm
82
, and a wrist
83
. The first arm
81
, second arm
82
, and wrist
83
are rotatably attached around respective unillustrated vertical shafts of the arm supporting slider
7
, the first arm
81
, and the second arm
82
, respectively, and driven by an unillustrated motor. At the front end of the wrist
83
, an unillustrated hand, etc. is attached, whereby the hand holds articles.
Thus, this horizontal multi-joint type pelletizing robot works to carry articles held by the hand to an optional location and load them following commands by an unillustrated controller.
However, in
FIG. 2
when the feed screw
6
is attached to the supporting frame
1
, it is difficult to correctly adjust and position the feed screw
6
. The feed screw
6
must be positioned on the basis of both the direct-acting guide
2
and power transmission device
4
. This problem is described as follows.
For positioning of the feed screw
6
, the following procedures are required: (1) the power transmission device
4
is fixed to the bottom plate
13
; (2) the lower end part of the screw body
61
is inserted into the power transmission device
4
, and the lower bearing
64
is fixed to the power transmission device
4
; (3) the upper bearing
63
is temporarily fixed to the power transmission device
4
; and (4) on the basis of the attaching position of the lower bearing
64
, while measuring the distance and inclination of the feed screw
6
from the direct-acting guide
2
, the fixing positions of the nut part
62
and upper bearing
63
are finely adjusted so that a predetermine parallel condition is obtained.
Thus, the simultaneous fine adjustments of the two fixing positions of the nut part
62
and upper bearing
63
on the basis of the attaching position of the lower bearing
64
are troublesome operations and take time.
Also, unless the feed screw
6
is removed, since the power transmission device
4
cannot be removed from the supporting frame
1
, in order to replace and fix the power transmission device
4
, the feed screw
6
must be removed, and positioning of the feed screw
6
must be performed at each time of replacement.
Furthermore, since the supporting frame
1
needs precise machining for the three surfaces of the top plate
11
, bottom plate
13
, and middle plate
14
, machining man-hours increase, and the cost also increases.
SUMMARY OF THE INVENTION
The object of the invention is, therefore, to provide an industrial robot in which the feed screw can be easily positioned in relation to the direct-acting guide, while having a power transmission device that can be removed from the supporting frame while the feed screw is left attached to the supporting frame.
In order to solve the above problems, a feed screw supporting member is attached to a supporting frame. The feed screw is positioned and fixed to the feed screw supporting member at a predetermined relative position from the direct-acting guide, and a power transmission device is positioned based on the feed screw, and fixed to the screw supporting member. Also, a space is provided between the supporting frame and power transmission device by which, while the feed screw is left attached to the feed screw supporting member, the power transmission device is removed from the feed screw supporting member, and the front end of the feed screw is pulled and removed from the power transmission device provided, whereby the power transmission device can be pulled out from the supporting frame.
REFERENCES:
patent: 5085556 (1992-02-01), Ohtomi
patent: 5087169 (1992-02-01), Tiibke
Fujii Nobuaki
Matsushita Shigeo
Ookura Masahiko
Armstrong Westerman Hattori McLeland & Naughton LLP
Dang Khanh
Kabushiki Kaisha Yaskawa Denki
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