| 摘要 |
<p>1463796 Removing dust generated in industrial processes R HIRDES 30 June 1975 [26 July 1974] 27568/75 Heading F4X A dust extraction device attachable to a hand-operated machine, e.g. a rotary drill 3 or grinding wheel, comprises a housing 1 connectible to a suction source through a nozzle 2. The housing adjacent the drill tip 3<SP>11</SP> is formed by a flat disc 1<SP>11</SP> having a first aperture surrounded by a resilient sealing lip 11 to contact the workpiece and a second aperture 12 is formed in the face of the disc remote from the lip. The apertures are in register to allow the drill to pass therethrough and the aperture 12 both allows suction air to flow thereinto concentrically around the drill and also acts as an inspection orifice during operation. The device is positioned relative to the machine by clamps 4 and a clamping screw 8, rods 5 surrounded by helical springs 6 passing through the clamps being secured to the housing 1 and held in position by grub screws 7 so as to bias the housing from the machine. The housing comprises a cylindrical cover member 1<SP>1</SP> provided with the nozzle 2 and the disc 1<SP>11</SP> is rotatable relative thereto by co-operating collars 10<SP>1</SP>, 10<SP>11</SP>. The crosssectional area of the aperture 12 and nozzle are substantially similar.</p> |
