| 摘要 |
PROBLEM TO BE SOLVED: To provide a durable spike that can maintain spike functions for a longer period by avoiding looseness and rotation resulted from wear or uneven wear of its spike body and stem or preventing degradations in the spike functions, accidental spike release, and resultant stem breakage and accidental spike-body separation. SOLUTION: A spike head 1 of a harder metal has on its back face 11 a fitting projection or male portion 12, from which a mounting stem portion 13 extends in a setback fashion ensuring a step 12a. At least either of the fitting male portion 12 and the mounting stem portion 13 has a cross section presenting a polygon, ellipse or the like other than a circle. A threaded portion 15 further extends from the mounting stem portion 13. A spike body 2 of a less hard metal has, in its end face 23 butting against the back face 11 of the spike head 1, a fitting hole 28 conforming to the fitting male portion 12 and a through hole 29 conforming to and receiving the mounting stem portion 13 which extends through it. With the fitting male portion 12 and mounting stem portion 13 fitted in the fitting hole 28 and through hole 29, the spike head 1 and spike body 2 are protected against relative rotation and separation.
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