Conveyors: power-driven – Conveyor having impinging fluid to feed – shift or discharge... – Having cleaning means
Reexamination Certificate
2002-08-29
2004-07-27
Ridley, Richard (Department: 3651)
Conveyors: power-driven
Conveyor having impinging fluid to feed, shift or discharge...
Having cleaning means
C414S940000, C384S015000
Reexamination Certificate
active
06766895
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a work conveying system and a traveling path sealing structure therefor. In particular, the present invention is concerned with an improvement in a work conveying system and a traveling path sealing structure wherein, in a production line installed within a clean room for the production of, for example, semiconductor components, liquid crystal display panels, medical supplies, drugs, or processed foods, dust generated in the interior of a traveling path (guide rail) in the work conveying system is prevented from leaking out into the clean room, and the work conveying system is adapted to convey a workpiece to each of plural processing stations.
2. Description of the Prior Art
In a semiconductor integrated circuit or a liquid crystal display panel, the deposition of dust causes a lowering of product yield. In the case of medical supplies, drugs and processed foods, it is desirable to produce them in a sterile and sanitary environment. In this connection, intra-clean room production lines are utilized in a wide variety of fields, and various technical developments have been made with respect to various processing chambers and work conveying systems installed within clean rooms.
An overhead traveling type work conveying system which is one type of work conveying system has been developed. According to this work conveying system, the mode of layout of various process devices to be installed within a clean room is not restricted and it is possible to select an optimum layout, that is, it is possible to utilize the interior of the clean room effectively and it is thereby possible to reduce the equipment cost and operation cost of the clean room. The adoption of such an optimal layout is also advantageous in that the work conveying system which can be a source of dust (particles) can be kept separate from apparatuses such as the various processing chambers installed within the clean room.
The present applicant previously invented a work conveying system provided with moving means capable of moving a work holding means arbitrarily in three dimensions in the upper ceiling space within the clean room (see Japanese Patent Laid Open No. 2000-243808).
In applicant's previous work conveying system, a pair of horizontal fixed guide rails are laid in parallel within a ceiling space and one or plural horizontal traveling guide rails extend between the pair of fixed guide rails and are adapted to travel along the fixed guide rails. On each traveling guide rail is provided a traveling block which can travel along the traveling guide rail. The horizontal moving means includes the fixed guide rails, traveling guide rail(s), and a traveling block. Further, the traveling block is provided with a vertical moving means for moving the work holding means up and down. The three-dimensional moving means is the combination of the horizontal moving means and the vertical moving means.
The fixed and traveling guide rails, which are each in the form of an elongated duct, contain a drive (including a drive motor and a drive mechanism) for the traveling guide rail and the traveling block, also contain a power supply means, and are in communication with each other. Dust (particles) generated from the drive portion and the various slide connections is confined in the ducts which constitute the fixed and traveling guide rails and is evacuated from one end of a communication path and discharged to the exterior of the clean room. In this way contamination of the clean room caused by dust from within the ducts which constitute the guide rails is prevented to a considerable extent.
While the dust present within the ducts is evacuated from one end of the communication path and is discharged to the exterior of the clean room, there is the danger that the dust may leak into the clean room from an elongated gap in the duct, where the drive portion thereof extends through the duct or where a connecting member, for connection between the traveling block and the drive portion, extends through the duct.
FIG. 17
illustrates a sealing structure in this work conveying system, which closes an elongated gap
028
formed to allow for a connecting member
022
which connects a traveling guide rail
015
with a drive section (including a drive motor
023
and a drive roller
026
) and extends through a duct
017
from a fixed guide rail
014
. In this sealing structure, the connecting member
022
has a zigzag-bent sectional shape and shield plates
041
a
and
041
b
are inserted deep into slits
022
a
and
022
b
of the connecting member
022
, thereby forming a labyrinth to prevent dust generated in the drive and slide portions in the duct from leaking out into the clean room. However, even with such a labyrinth structure, since the dust is evacuated through a long path, it has so far been impossible to completely prevent the dust present in the duct from leaking out into the clean room.
Other examples of overhead traveling type work conveying systems are disclosed in Japanese Patent Laid Open Nos. 1993-116885, 1993-39030, and 1995-291123. In these work conveying systems, a roller provided in a traveling body is adapted to roll on a rail laid on the ceiling. But the drive for the traveling roller is covered with a cover member attached to the traveling body itself, so that dust generated in the drive and in a slide connection between the traveling roller and the rail is released into the clean room. Since the above-described conventional apparatus is not dedicated to a clean room, it is not applicable to a clean room for which a high degree of cleanliness is required.
SUMMARY OF THE INVENTION
It is an object of the present invention to solve the above-mentioned problems of the conventional overhead traveling type work conveying system and to provide a work conveying system and a traveling path sealing structure in the work conveying system which can prevent dust generated by a drive mechanism and various slide connections from leaking out into a clean room, the work conveying system comprising fixed guide rails and a traveling guide rail(s), and to thereby prevent a lowering in the degree of cleanliness of the clean room more effectively.
For achieving the above-mentioned object, in a first aspect of the present invention there is provided a work conveying system comprising a least a work holding means for holding a workpiece and a horizontal moving means for moving the work holding means horizontally in an upper ceiling space within a clean room, the workpiece being conveyed to each of plural processing apparatuses, wherein the horizontal moving means has at least one linear moving mechanism, the linear moving mechanism comprising a traveling path covered with a duct and having a guide in the interior of the duct, a traveling body adapted to engage the guide and travel through the interior of the duct, and a slider located on the exterior of the duct and connected to the traveling body for travel together with the traveling body. The work holding means or another linear moving mechanism is attached to the slider, and cleaning means are disposed at suitable intervals along the traveling path to clean the air present within the duct and to discharge the cleaned air to the exterior.
Since the traveling body, which is one component of the linear moving mechanism provided in the horizontal moving means, is adapted to engage the guide located within the duct and to travel along the traveling path therein, dust generated from a slide connection by which the traveling body and the guide are engaged with each other, is confined within the duct and the possibility of its leaking out into the clean room is decreased. Since cleaning means for cleaning air within the duct and discharging it to the exterior are disposed at suitable intervals along the traveling path, dust laden air is evacuated from the duct, cleaned in a unit serving a relatively short traveling path, and the cleaned air is discharged to the exterior. Thus, it is possible to greatly
Hirata Corporation
Lorusso, Loud & Kelly
Ridley Richard
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