| 摘要 |
<p>A dust extraction shroud for a hammer, which surrounds a drill bit mounted in the hammer, and which lies adjacent the work surface which is being penetrated by the drill bit, when the hammer is in use. The shroud is connected to a vacuum cleaner so that the air and dust, generated by the drilling action, in the shroud is removed and sucked into the vacuum cleaner. The shroud comprises a body portion defining:- at least one first inlet adapted to engage the surface of the workpiece and to surround a location at which said working member penetrates the surface; at least one first outlet adapted to be connected to a source of suction; at least one second inlet for enabling air to enter said body portion and travel to at least one said first outlet; a third inlet for allowing said working member to pass through said body portion and at least one said first inlet; and first sealing means arranged in said third inlet for surrounding said working member and resisting flow of air from the interior of said body portion out of said third inlet; wherein said body portion includes at least one protruding portion defining a respective said second inlet between said protruding portion and part of said body portion adjacent thereto, and on a side of said protruding portion remote from the or each said first inlet. <IMAGE></p> |
