| 摘要 |
PURPOSE: A screw piece for insulation of a concrete wall is provided to firmly secure insulation and finishing material to the concrete wall by employing screw thread of double sheet structure. CONSTITUTION: A screw piece(40) for insulation of a concrete wall comprises a cone-shaped head(41), a rod type shaft(42), main thread(43), and sub thread(44). A tool joint groove(42) is formed on the top of the head. The shaft has a sharp projection(46) on the tip. The main and sub thread are formed in a double structure from the top to the bottom of the shaft. The main and sub threads are projected in the shape of thin plate.
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