| 摘要 |
A pin for a sweeper used to scrape scale off the inner wall of a pipe has a shaft portion, an anchoring portion at the lower end of the shaft portion for being driven into the sweeper body to prevent the pin from falling out, and a head portion at the upper end of the shaft portion. The head portion has a plurality of spaced, generally pyramidal projections for contacting and scraping off scale. The projections are arranged in such a manner that the tip portions thereof do not overlap one another when the head portion is viewed from the side. The head portion may alternatively include a plurality of stacked plate-shaped bodies each of which has corner portions. The plate-shaped bodies are stacked on one another and are successively angular offset in the same direction in such a manner that equal angles are formed between corresponding corner portions of mutually adjacent ones of the plate-shaped bodies. |
