| 摘要 |
The retention device is rotatably fixed to the cutting blade (2) via a second rotary axis (7b) and a spring component (4) works in conjunction with and extends between the cutting blade and the plough. When the cutting blade collides with a minor obstruction, the blade and the arm (7) pivot under the effect of the obstruction from the normal position against spring force effect, to allow the blade lower edge part to pass over the obstruction. After this, the blade is pressed by spring force back to its normal position and that of the arm. - The plough is provided with a stop (8) for the cutting blade and/or arm. When the bladqe encounters a large obstruction, blade and arm pivot, towards the stop. In this position the cutting blade rotates around the second rotary axis so that the blade lower edge part passes over the obstruction, after which the blade is pushed back to its normal position and that of the arm. |
