| 摘要 |
In the case of pneumatic hammer drills, a pneumatic-spring volume which is as small as possible is required in the return phase of the impact member and a pneumatic-spring volume which is as large as possible is required in the impact phase, in order to ensure reliable return of the impact member and avoid sharp pressure peaks during impact. In order to fulfill these opposite requirements, a previously known solution which employs an air chamber with variable volume is improved in that two air chambers (4, 5; 54, 55) are connected in series. This is done not only such that in the return phase only one chamber (4; 54) and in the impact phase both chambers are active with their pneumatic springs; rather, the effect of the arrangement is further increased by subjecting a chamber (5; 55) to elevated gas pressure with the use of a valve (20; 70) and utilisation of the mass inertia of the impact member (6, 36, 56). As a result, inter alia, an increase in the recoil damping in these hand tool machines is achieved. <IMAGE>
|
