| 摘要 |
A cultivator or rotary harrow has tined soil working members that are driven about upwardly extending axes. At least one, but preferably substantially all, of the soil working members have an overload release between the driving system and the tines so that when an immovable object is encountered by a tine, the drive to the respective soil working member is temporarily disconnected. The release can be between two parts that are normally spring biased together to maintain the driving engagement to the soil working member. In one form, a pinion gear to the soil working member has an outer toothed portion that can rotate relative to a central portion that is connected to the rotary shaft mounting the soil working member. Ball members in channels formed in the central portion are biased radially into recesses of the toothed portion. In another form, ball members are biased radially to engage the soil working member to its corresponding rotary shaft. Also, the upper end of the rotary shaft can be secured to a pinion by a split ring held in a spacing sleeve. The lower shaft end can be attached to a tine support and normally connected for rotation by a lower part that is fitted in a recessed part in the bottom of the support and spring biased in the recess. Upon a tine striking an immovable object, the parts ride out of engagement, but the parts reconnect upon passing the object.
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