摘要 |
Agricultural tractors having variable-track wheels for working in different conditions, particularly in row-crops, are known. The track-width of their driving wheels has sometimes been made power-adjustable by fixing brackets having respective grooves on the periphery of each hub and releasably clamping the brackets to respective helical rails fixed inside each rim and engaging the grooves. Due to the increasing size and power of tractors, and also to eventual wear of the components, it is difficult to achieve effective clamping. In an attempt to solve the problem, shims have been inserted where necessary between the brackets and the periphery of each hub. It is now proposed to solve the problem more positively by providing at least some of the brackets of each wheel with screws by which the brackets so provided can be adjusted in position radially of the hub before being fixed thereto.
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