Material or article handling – Horizontally swinging load support – Swinging about pivot
Reexamination Certificate
1999-05-27
2001-02-20
Underwood, Donald W. (Department: 3652)
Material or article handling
Horizontally swinging load support
Swinging about pivot
C074S490010, C414S917000
Reexamination Certificate
active
06190114
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a transfer robot used for semiconductor manufacturing equipment, liquid crystal display processing equipment and the like. More particularly, the present invention relates to a transfer robot for transferring workpieces between processing chambers under a vacuum.
2. Description of the Related Art
Conventionally, use has been made of various kinds of transfer robots designed for semiconductor manufacturing equipment, liquid crystal display processing equipment and the like.
FIGS. 15-17
of the accompanying drawings illustrate an example of a conventional transfer robot.
AS shown in
FIG. 17
, the conventional transfer robot is provided with a handling member
84
. Though not illustrated, an object to be processed (called “workpiece” hereinafter), such as a silicon wafer, is placed on the handling member
84
. The handling member
84
, which is carried by an arm mechanism, is arranged to move horizontally in a straight line as well as to rotate in a horizontal plane around a central axis P
1
. A plurality of processing chambers
71
-
76
for performing predetermined processing are disposed around the central axis P
1
. With the use of the transfer robot, the workpiece is automatically brought to and taken away from a selected one of the processing chambers
71
-
76
.
Referring to
FIG. 15
, the conventional transfer robot includes a rotatable base
81
and a first arm
82
. The rotatable base
81
is caused to rotate about a first axis P
1
by a driving motor, while the first arm
82
is caused to rotate about the first axis P
1
by another driving motor which is fixed to the rotatable base
81
.
In
FIG. 15
, reference number
83
refers to a second arm which is rotatable about a second axis Q
1
relative to the first arm
82
, while reference numeral
84
refers to a handling member which is rotatable about a third axis R
1
relative to the second arm
83
.
Reference numeral
85
refers to a first rotation-transmitting member which is fixed to the rotatable base
81
coaxially with the first axis P
1
, while reference numeral
86
refers to a second rotation-transmitting member which is fixed to the second arm
83
coaxially with the second axis Q
1
. Reference numeral
87
refers to a third rotation-transmitting member fixed to the first arm
82
coaxially with the second axis Q
1
, while reference numeral
88
refers to a fourth rotation-transmitting member fixed to the handling member
84
coaxially with the third axis R
1
.
A first connecting member
89
is provided between the first rotation-transmitting member
85
and the second rotation-transmitting member
86
. Also, a second connecting member
90
is provided between the third rotation-transmitting member
87
and the fourth rotation-transmitting member
88
. The distance S between the first and second axes P
1
, Q
1
is equal to the distance between the second and third axes Q
1
, R
1
. The radius ratio of the first rotation-transmitting member
85
to the second rotation-transmitting member
86
is 2 to 1. The radius ratio of the fourth rotation-transmitting member
88
to the third rotation-transmitting member
87
is also 2 to 1.
Chain sprockets or pulleys may be used for the first to fourth rotation-transmitting members
85
-
88
. Correspondingly, the first and second connecting members
89
,
90
may be chains or timing belts.
Reference will now be made to the operation of the arm mechanism of the conventional transfer robot.
At the outset, it is assumed that the rotatable base
81
is kept stationary, and that the first, second and third axes P
1
, Q
1
, R
1
are initially located in a common straight line, as shown in FIG.
16
. Starting from this state, the first arm
82
is rotated counterclockwise through an angle &thgr; about the first axis P
1
.
During the above operation, the first rotation-transmitting member
85
is fixed in position, while the second axis Q
1
is moved counterclockwise around the first axis P
1
through the angle &thgr;. (Thus, the second axis Q
1
is shifted from the initial position to a new position Q
11
.) As a result, a Y
1
-side portion of the first connecting member
89
is wound around the first rotation-transmitting member
85
, whereas a Y
2
-side portion of the same connecting member is unwound from the first rotation-transmitting member
85
. Thus, as shown in
FIG. 16
, the first connecting member
89
is moved in a direction indicated by arrows a
1
and a
2
. As a result, the second rotation-transmitting member
86
is rotated clockwise about the second axis Q
1
.
As mentioned above, the radius ratio of the first rotation-transmitting member
85
to the second rotation-transmitting member
86
is 2 to 1. Thus, when the first arm
82
is rotated counterclockwise about the first axis P
1
through the angle &thgr;, the second rotation-transmitting member
86
is rotated clockwise about the second axis Q
11
through an angle 2&thgr;.
At this time, since the second rotation-transmitting member
86
is fixed to the second arm
83
, the second rotation-transmitting member
86
and the second arm
83
are rotated clockwise about the second axis Q
1
through an angle 2&thgr;.
If the second arm
83
did not change its orientation relative to the first arm
82
, the third axis R
1
would be brought to an R
11
position shown by broken lines. Actually, however, the second rotation-transmitting member
86
is rotated clockwise about the second axis Q
11
through an angle 2&thgr;. Therefore, the third axis R
11
is moved clockwise about the second axis Q
11
through the same angle 2&thgr; to be brought to the R
12
position. This means that the third axis third axes P
1
and R
1
even while the first arm
82
is being rotated counterclockwise about the first axis P
1
through an angle &thgr;.
When the second arm
83
is rotated clockwise about the second axis Q
11
through an angle 2&thgr;, thereby bringing the third axis R
11
to the R
12
position, a Y
2
-side portion of the second connecting member
90
is wound around the third rotation-transmitting member
87
, whereas a Y
1
-side portion of the same connecting member is unwound from the third rotation-transmitting member
87
.
As a result, the second connecting member
90
will be shifted in a direction b
1
-b
2
shown in FIG.
16
. Thus, the fourth rotation-transmitting member
88
is rotated counterclockwise about the third axis R
12
.
When the second arm
83
is rotated clockwise about the second axis Q
11
through an angle 2&thgr; as stated above, the fourth rotation-transmitting member
88
is rotated counterclockwise about the third axis R
12
through an angle &thgr; (since the radius ratio of the fourth rotation-transmitting member
88
to the third rotation-transmitting member
87
is 2 to 1). As a result, a point C
0
of the fourth rotation-transmitting member
88
is brought to a position C
1
on the straight line passing through the first and the third axes P
1
, R
12
.
Upon rotation of the first arm
82
about the first axis P
1
in the counterclockwise direction as described above, the handling member
84
is moved along the line passing through the first and the third axes P
1
, R
1
. During this operation, the handling member
84
does not changed its attitude or orientation since it is fixed to the fourth rotation-transmitting member
88
.
The transfer robot having the above-described arrangement is installed at the center of the processing chambers
71
-
76
, as shown in FIG.
17
. Workpieces are transferred by the transfer robot between these chambers
71
-
76
.
Though useful in many respects, the conventional transfer robot has been found disadvantageous in the following points.
First, as shown in
FIG. 15
, the second arm
83
incorporates the fourth rotation-transmitting member
88
and the second connecting member
90
. In this arrangement, the second arm
83
is rendered to have an unduly great thickness H
1
.
Second, since the non-illustrated driving motor for actuating the arm mechanism is mounted on the rotatable b
Kamitani Masashi
Ogawa Hironori
Daihen Corporation
Merchant & Gould P.C.
Underwood Donald W.
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