| 摘要 |
<p>Turf maintenance machines have working units which are desirably counterbalanced at least partially in the working position to allow floating over ground contours. Known machines tend to have a relatively wide variation in the counterbalanced weight over the range of working levels. The invention provides a machine with a gas spring (67) which applies an almost constant force and is located to act so that the resultant weight of its associated unit is substantially constant at all working levels. Preferably this is achieved by having the inner end of a lifting and lowering arm (23) supporting a lateral unit (15) welded to a sleeve (39), freely rotatable on a shaft (27), which carries a pair of cranks (43, 47) to which the gas spring and an hydraulic lifting and lowering ram (51) are pivotally connected. The machine may have two lateral units (15, 17) on opposite sides and a central unit all counterbalanced by gas springs.</p> |
