US patent # 5,788,300 - Canadian patent # 2,158,611
Comments from a satisfied customer:
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..We saw the Dalla-Bona crane with the new modified grapple in operation ... and were so impressed with the efficiency and simplicity of the loading operation using the Dalla-Bona crane that we purchased one....
...We anticipate considerable savings as a result of using this new unit as it will allow us to load and unload with only one person....