| 摘要 |
<p>A crank mechanism for a hammer drill comprising: a crank plate 152 capable of being rotated about an axis of rotation 814, the crank plate 152 having a recess 172 with an entrance 512 formed within a surface of the crank plate 152; a crank pin 154 comprising a bearing 170 rigidly attached to one end of the crank pin 154, the bearing being of sufficient size and shape relative to the size and shape of the recess that it is able to be located within the recess in a pivotal manner; wherein the size and shape of the bearing in relation to the size and shape of the entrance is such that when the bearing is in at least one orientation relative to the entrance, it is able to pass through the entrance of the recess and locate within the recess and when the bearing is located within the recess and it is orientated to at least one second orientation relative to the entrance, it is prevented passing through the entrance and exiting the recess.</p> |
