| 摘要 |
In a hollow earth auger head assembly a plurality of bit-holding pockets a re provided, spaced circumferentially from one another around an open mouth of an auger head, and bits taken selectively from a multiplicity of types of cutting teeth, have a shank portion that seats in any and all of the pockets. A retaining pin extends chordally, off-set from a diameter, through holes in the pocket and into a retaining pin receiv er in the bits. In those bits that are intended to rotate in the pocket, the retaining receiver takes the form of an annular channel. In those bits that are not supposed to rotate, the retaining pin extends through a linear passage in or along a flat on the bit shank. In certain embodiments of sockets a chordal plug or weldment defines a space with one flat side against which a tail of the shanks of certain bits designed not to rotate bear.
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