| 摘要 |
A fastener in accordance with this invention is a pin member usable with a collar to fasten a joint. The pin member comprises a head and an integrally formed shank extending therefrom. The shank includes a locking portion formed with a plurality of ribs separated from each other by locking grooves, the depth of which are all substantially equal to each other. At least one of the ribs is formed with a portion symmetrical about a line extending at a right angle to the axis of the shank and a portion asymmetrical about that line. Preferably all of the ribs have a radiused crest.
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