| 摘要 |
<p>A hedge trimmer having two counter reciprocating cutting blades, each of the blades having a yoke at one end defining a cam follower slot, the cutting blades being held together by mounting means which hold the yokes in close face-to-face contact, and a double cam drive engagable with the cam follower slots, the double cam drive being so designed that one cam cannot interfere with the cam follower slot which is adapted to be engaged by the other cam. The cams are so positioned with respect to each other that the periphery of one cam entirely surrounds the periphery of the other cam. The cams, which are circular, are mounted upon one side of a drive member with the axes of the two cams lying on opposite sides of the axis of the drive member. Preferably the axis of one of the cams is spaced further away from the axis of the drive member than the other cam member, this cam engaging a cutting blade of lower mass than the other cutting blade in order to counterbalance the inertial forces created by the reciprocating cutting blades. Alternatively, the blades may be of equal mass and the axial spacing of the cams equal to achieve counterbalance.</p> |
