| 摘要 |
PROBLEM TO BE SOLVED: To airtightly seal a work support stand 31 and the peripheral edge part of an opening 10 at the closing position of the rising end of the work support stand 31 by an inexpensive and simple structure when the opening 10 of the bottom wall part 9 of each of load lock chambers 5 and 6 is opened and closed by the vertically-travelling work support stand 31. SOLUTION: The work support stand 31 is supported by a balance chain 50 and a balancing elastic mechanism 65, which has an energizing spring 68 contracted in its length direction when tension of a predetermined value or more is applied to the balance chain 50 by the rising drive force of the work support stand 31 to energize the front end of the work support stand 31 in a rising direction, is connected in series. An elastic mechanism 72 for a lift means having an energizing spring 75, which is contracted in the lift direction of the work support stand 31 when rising drive force of a predetermined value or more is applied to the work support stand 31 from a lift chain 63 to energize the rear end of the work support stand 31 in a rising direction, is provided between the work support stand 31 and the lift chain 63. The work support stand 31 is pressed to the bottom wall part 9 around the opening 10 at the closing position by the energizing force of the elastic mechanisms 65 and 72.
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