Receptacles – Closures – Having means for securing or retaining closure in its closed...
Reexamination Certificate
2001-03-20
2002-10-01
Newhouse, Nathan J. (Department: 3727)
Receptacles
Closures
Having means for securing or retaining closure in its closed...
C206S001500, C206S710000, C292S066000
Reexamination Certificate
active
06457598
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wafer transport module and, more specifically, to a door latch transmission mechanism for a module cover for wafer transport module, which can smoothly accurately be moved between the locking position and the unlocking position with less effort.
2. Brief Description of the Prior Art
Before becoming an IC chip, a wafer must be processed through a series of processing procedures including diffusion, printing, etching, masking, reading, and etc. Transport means are used in factory to deliver wafers from one working area to another. These transport means (cassette, boat, POD, or FOUP) are mainly to protect wafers against contamination of dust and external objects.
FIG. 1
illustrates a transport means for this purpose. This transport means is constructed according to U.S. Pat. No. 5,915,562, issued to Nyseth et al., entitled “Transport Module With Latching Door”. The wafer transport module
1
comprises a module body
10
and a module cover
20
. The module body
10
is adapted to carry wafers W, having an opening
11
at one side thereof and a plurality of latch holes
13
disposed around the opening
11
. The module cover
20
comprises an outer cover panel
21
, and at least one door latch
27
respectively slidably disposed on the inside. The outer cover panel
21
of the module cover
20
comprises at least one lock cylinder hole
25
or rotary handle
253
. An implement can be inserted to rotate each lock cylinder hole
25
and rotated to move the respective door latch
27
in and out of a corresponding peripheral through hole
23
of the module cover
20
. Alternatively, the user can directly rotate the rotary handle
253
to move the respective door latch
27
in and out of the corresponding peripheral through hole
23
of the module cover
20
. In order to let the module cover
20
close the opening
11
of the module body
10
tightly to protect storage wafers W against outside dust, the door latch
27
will be moved forwards (toward the corresponding latch hole
13
) and then outwards (toward the outer cover panel
21
) when extending out of the respective peripheral through hole
23
, to engage the corresponding latch hole
13
. To achieve this function, the door latch transmission mechanism of the aforesaid design comprises a rotary wheel
29
. The rotary wheel
29
comprises a protruded center mount
293
aimed at one lock cylinder hole
25
on the outer cover panel
21
for receiving an implement being inserted into the lock cylinder hole
25
for enabling the rotary wheel
29
to be rotated by the implement, at least one first eccentric guide slot
295
and at least one second eccentric guide slot
296
. The door latch
27
comprises a first latch
271
and a second latch
272
. The first latch
271
has a front coupling rod
275
coupled to one first eccentric guide slot
296
of the rotary wheel
29
. The second latch
272
has a front coupling rod
276
coupled to one second eccentric guide slot
296
. When rotating the rotary wheel
29
, the first latch
271
and the second latch
272
are respectively moved. The first latch
271
and the second latch
272
are arranged in a stack. After extended out of the respective peripheral through hole
23
(the X-axis direction), the first latch
271
is forced by the second latch
272
to move in Y-axis direction and to engage the corresponding latch hole
13
. This design of door latch transmission mechanism has numerous drawbacks as outlined hereinafter.
1. Because the second latch forces the first latch into engagement with the corresponding latch hole, dust tends to be produced to contaminate storage wafers during friction between the first latch and the second latch.
2. Because the second latch rubs against the inner surface of the outer cover panel of the module cover during its movement, dust may be produced to contaminate storage wafers due to friction between the second latch and the inner surface of the outer cover panel.
3. During sliding movement of the door latch, much resistance is produced against the movement of the first latch and the second latch, and therefore much effort must be employed to rotate the rotary wheel.
4. Because the second latch is adapted to force the first latch into engagement with the corresponding latch hole, the first latch and the second latch must be will matched. Therefore, the fabrication of the component parts of the door latch transmission mechanism is complicated.
SUMMARY OF THE INVENTION
The invention has been accomplished under the circumstances in view. It is therefore the main object of the present invention to provide a module cover for a wafer transport module, which eliminates the aforesaid drawbacks. It is another object of the present invention to provide a module cover, which greatly reduces the production of dust when operated to close/open the wafer transport module. It is still another object of the present invention to provide a module cover for a wafer transport module, which can easily be opened and closed with less effort. It is still another object of the present invention to provide a module cover for a wafer transport module, which has a simple structure and, is inexpensive to manufacture. To achieve these and other objects of the present invention and according to one aspect of the present invention, the module cover assembly comprises a module cover and at least one door latch transmission mechanism adapted to lock/unlock the module cover. The at least one door latch transmission mechanism each comprises a door latch supported on a roller at the module cover, a latch bolt pivotally coupled between one end of the door latch and a part of the module cover, and a driving wheel coupled to the module cover and rotated to move the door latch forwards and backwards and to further turn the latch bolt in and out of a through hole on the module cover and a respective latch hole on the wafer transport module to lock/unlock the module cover. According to another aspect of the present invention, the driving wheel of each door latch transmission mechanism comprises a center mount coupled to a handle means that is disposed outside the module cover for operation by hand to rotate the driving wheel, and a smoothly arched eccentric guide slot; the door latch of each door latch transmission mechanism comprises an upright coupling rod disposed at one end and coupled to the smoothly arched eccentric guide slot of the respective driving wheel for enabling the door latch to be moved forwards and backwards by the respective driving wheel.
REFERENCES:
patent: 5915562 (1999-06-01), Nyseth
patent: 5931512 (1999-08-01), Fan et al.
patent: 5957292 (1999-09-01), Mikkelsen et al.
patent: 6105782 (2000-08-01), Fujimori et al.
Chen Jone Nan
Hsieh Chang Yu
Newhouse Nathan J.
Prosys Technology Integration, Inc.
Rosenberg , Klein & Lee
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