PURPOSE: To improve a lift of a digging tool by forming the periphery of almost semicircular blocks of a circular arc of different radius and the block, placed in a side of protruding from the peripheral surface of a device when it is rotated, in a peripheral radius larger than that of the block in the other side.
CONSTITUTION: The periphery of blocks 10a, 10b of semicircular shape as viewed in the bottom surface is constituted of circular arcs S1, S2 of different radius and a curve S3 of connected these circular arcs. Next, many bits 4... are implanted in point end surfaces of the blocks 10a, 10b and in a part of a protruding side by forming a radius R1, which constitutes the periphery of the part in the protruding side of the blocks 10a, 10b, larger than a radius R2 in a not protruding side. When the ground is excavated by rotating a device 2, the bits 4... in this protruding part are prevented from wearing, because the many bits 4... are implanted in this part, even for a large amount of work in the protruding part of the block 10a. In this way, a lift of a tool can be improved.
SATO SHIGERU
TSUJIMOTO KATSUAKI
JPS5976391A | 1984-05-01 |
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