| 摘要 |
<p>The invention is directed to a dust seal arrangement for a portable tool such as drill, hammer-drill, rotary hammer or the like having a bit receiving end for receiving a tool bit therein. The dust seal arrangement includes a dust seal (15) which coacts with the tool bit (60) and the bit receiving end (13) of the tool. The tool bit (60) and tool receiving end (13) have respective surfaces (32), (43) disposed in surrounding relation to the common longitudinal axis of the tool bit (50) end tool receiving end (13). The dust seal (15) has a first end portion (27) defining an axially extending opening (29) of predetermined dimension, shaped to coact with the surface (32) of the tool bit (50) to provide a first interference fit therewith. A second end portion (35) of the dust seal (15) is axially spaced from the first end portion (27) and is connected thereto. The second end portion (35) has a second axially extending opening (39) of predetermined dimension shaped to coact with the surface (43) of the bit receiving end (13) to provide a second interference fit therewith. The second interference fit is lighter then the first interference fit such that the seal (15) moves substantially in unison with the bit (50) while slipping upon the contacted surface (43) of the bit receiving end (13). </p> |
