Material or article handling – Horizontally swinging load support – Swinging about pivot
Reexamination Certificate
2001-11-05
2003-12-02
Underwood, Donald W. (Department: 3652)
Material or article handling
Horizontally swinging load support
Swinging about pivot
C414S744300, C901S015000
Reexamination Certificate
active
06655901
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 manufacturing equipment and the like. More particularly, the present invention relates to a three-dimensionally movable transfer robot for transferring workpieces such as wafers between a wafer processing apparatus and a wafer stocker (which is located outside the processing apparatus) for example.
2. Description of the Related Art
As shown in
FIG. 11
, in manufacturing liquid crystal panels for example, a transfer robot (not shown) is used for taking out a plurality of substrates
7
stored in a stocker
62
one by one for placement in a desired processing chamber or for returning the processed substrates
7
into the stocker
62
. The stocker
62
may be in the form of a cabinet including an opposite pair of side walls
62
a
. Each of the side walls
62
a
may be inwardly formed with a plural pairs of slots
62
b
for receiving the opposite side edges of the respective substrates
7
inserted into the stocker.
FIGS. 12 and 13
of the accompanying drawings illustrate two types of prior art transfer robots disclosed in JP-A-11-238779 for example. Specifically,
FIG. 12
illustrates a first type of prior art transfer robot R
1
which includes a hand
80
, a hand moving mechanism
8
for moving the hand
80
in an X direction (not shown) which extends horizontally, and a link mechanism
9
for moving the entire hand moving mechanism
8
. The link mechanism
9
includes a machine base
90
, a first arm
91
having a base end and a free end, a second arm
92
also having a base end and a free end, a first connecting portion
93
a
, a second connecting portion
93
b
, and a third connecting portion
93
c
. The first arm
91
is rotatably connected at the base end to the machine base
90
via the first connecting portion
93
a
and connected at the free end to the base end of the second arm
92
via the second connecting portion
93
b
. The free end of the second arm
92
is rotatably connected to an intermediate base member
81
of the hand moving mechanism
8
via the third connecting portion
93
c.
In the above-described transfer robot R
1
, the entire hand moving mechanism
8
is movable in both the Z direction (vertically) and the Y direction (extending horizontally but perpendicular to the X direction) by the rotation of the first and the second arms
91
,
92
of the link mechanism
9
. Moreover, by controlling the relative angle between the second arm
92
and the intermediate base member
81
in accordance with the inclination of the second arm
92
, it is possible to constantly keep the posture of the hand moving mechanism
8
horizontal.
FIG. 13
illustrates a second type of transfer robot R
2
. The transfer robot R
2
has a structure which is basically identical to that of the above-described transfer robot R
1
. Thus, the portions which are identical or similar to those of the transfer robot R
1
are designated by the same reference signs as those used for the transfer robot shown in FIG.
12
. The transfer robot R
2
differs from the transfer robot R
1
of
FIG. 12
in that the first arm
91
, which has a base end
91
a
and a free end
91
b
, is so rotatable as to allow the free end
91
b
to pass under the first connecting portion
93
a
. As compared with the transfer robot R
1
, the transfer robot R
2
is suitable for transferring workpieces at a lower position, because the hand moving mechanism
8
is capable of horizontally moving at a lower position.
However, the above-described transfer robot R
2
also has the following drawbacks.
A transfer robot needs to be capable of moving a hand horizontally and vertically along a straight line in as wide an area as possible while having a simple structure. However, the link mechanism
9
of the transfer robot R
2
is a so-called two-arm type mechanism which provides the hand with only a relatively narrow movable range in the Y direction and the Z direction. Specifically, since the length of the first arm
91
needs to be smaller than a distance between a floor surface and the connecting portion
93
a
, it is not possible to make the first arm
91
longer beyond a certain limit so that the maximum height of the hand
80
cannot be increased. If the length of the second arm
92
is increased for solving the above-described problem, it becomes difficult to move the hand
80
horizontally at a lower position, though the maximum height of the hand
80
increases.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a transfer robot which is capable of properly transferring workpieces linearly in a wide range.
Another object of the present invention is to provide a robotic transfer system incorporating such a robot.
In accordance with a first aspect of the present invention, there is provided a transfer robot which comprises a machine base, at least one hand for holding a workpiece, a hand moving mechanism for moving the hand horizontally reciprocally at least in an X direction, a first arm, a second arm, and a driving mechanism. The first arm has a base end and a free end. The base end of the first arm is connected to the machine base via a first connecting portion having an axis extending in the X direction, and the first arm is rotatable about the axis of the first connecting portion for allowing the free end to pass under the first connecting portion. The second arm also has a base end and a free end. The free end of the second arm is connected to the hand moving mechanism via a second connecting portion having an axis extending in the X direction. The driving mechanism causes the first arm to rotate about the axis of the first connecting portion while also rotating the hand moving mechanism about the axis of the second connecting portion. The transfer robot further includes an intermediate arm mechanism connected to the free end of the first arm via a third connecting portion having an axis extending in the X direction. The intermediate arm mechanism is also connected to the base end of the second arm via a fourth connecting portion having an axis extending in the X direction. The driving mechanism causes the intermediate arm mechanism to rotate about the axis of the third connecting portion while also causing the second arm to rotate about the axis of the fourth connecting portion.
According to the present invention, the link mechanism for moving the hand moving mechanism of the transfer robot includes a intermediate arm mechanism in addition to the first and the second arms. Therefore, by appropriately rotating the intermediate arm mechanism in addition to the first and the second arms, it is possible to make a movable range of the hand moving mechanism in the horizontal and the vertical directions larger than that of the prior art transfer robot which utilizes a two-arm type link mechanism. Further, the free end of the first arm can pass under the first connecting portion while keeping the posture of the intermediate arm mechanism generally horizontal. Therefore, the existence of the intermediate arm mechanism does not undesirably increases the height of the free end of the second arm. Thus, the hand moving mechanism can move horizontally at a relatively low position.
On the other hand, it is also possible to increase the maximum height of the hand moving mechanism by extending the intermediate arm mechanism generally vertically together with the first and the second arms. Moreover, it is also possible to increase the stroke of horizontal movement of the hand moving mechanism. Therefore, the transfer robot according to the present invention is useful in the case where the hand moving mechanism is required to move horizontally and vertically in a wide range. Further, according to the present invention, a size reduction of the transfer robot can be realized by increasing the movable range of the hand moving mechanism.
In one embodiment of the present invention, the intermediate arm mechanism includes only a single
Hoshijima Kohta
Tsubota Ryusuke
Daihen Corporation
Merchant & Gould P.C.
Underwood Donald W.
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