| 摘要 |
PROBLEM TO BE SOLVED: To provide a dust collection cup capable of securing dust compression efficiency by air while suppressing an aging decrease in suction air volume. SOLUTION: Openings are formed in a dust collection case 43 disposed in an air passage, and on the outlet side of the openings 73b-73h, other than the opening 73a, shielding plates 75b-75h are turnably mounted while urged in a direction closing the opening 73b-73h. While the amount of the collected dust is a relatively small, air passes through a filter 74a of the opening 73a to compress the collected dust, while securing the suction air volume. When the collected dust increases to close the opening 73a, the shielding plates 75b-75h are sequentially opened by a negative pressure against the urging to make the air pass through filters 74b-74h of the opening 73b-73h and compress the dust while securing the suction air volume. This constitution can secure the dust compression efficiency by the air while suppressing the aging decrease in suction air volume. COPYRIGHT: (C)2011,JPO&INPIT
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