PURPOSE: To reduce dust adhesion to a dust collecting part, by enabling a dust removing member for removing dust from the dust collecting part to be also used as a preliminary dust collecting part in combination for reducing a dust adhesion amount.
CONSTITUTION: During filtering, coarse dust is at first filtered by a prefilter 18 or separated from sucked air by collision. Only dust not separated by this mechanism is collected by a filter 15. Therefore, preliminary filtration is performed before reaching the filter 15 and the clogging of the filter 15 can be remarkably reduced as compared with a conventional apparatus. In removing dust, the support arm 21 of the prefilter 18 is reciprocally operated toward a direction parallel to the filter 15, that is, horizontally through a handle 19 and the top part of a filter material 22 is brought into contact with the bottom part of the filter to apply vibration to said filter 15. By this operation, the filter 15 and the prefilter 18 are mutually vibrated to simultaneously release and fall dusts therefrom.
OOKUMA YOUICHIROU
NAGASAWA KOUMEI
