| 摘要 |
The invention relates to a manually actuable toy sand dredger having a pivotable extension arm and two levers for raising and lowering the extension arm and for actuating a dipper shovel. A design which is used in kindergarten sandpits, for example, uses a four-bar mechanism as an extension arm, the web of which is mounted on one side and is connected to the lever to permit movement of the extension arm. The other lever is fastened to a crank which acts via a connecting rod on a rocker, to the extension of which there is fastened the dipper shovel. In addition to the danger of dirt collecting in the joints, there is also a danger that children playing with this toy will be injured, as the set of rods of the four-bar mechanism and/or the dipper shovel come so close to one another that there are points where catching or cutting may occur. According to the invention this danger is to be eliminated by means of a rigid extension arm which accommodates at least two pulleys or pinions in bearing blocks. A lever is fastened to the extension arm. The other lever is connected to a pulley or a pinion, the movements of which are transmitted via a belt or chain drive to the other pinion and from thence via a lever to the dipper shovel. The whole drive can be protected very well in this manner. Limiting the stroke can reliably eliminate the danger of catching or cutting.
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