| 摘要 |
PROBLEM TO BE SOLVED: To provide a core for a concrete form which is released from the form, by elastically deforming and reducing the size of a core form by simple operating procedures and easily maintained in good condition. SOLUTION: This core comprises a core form 3 with an opening part 2 formed across the entire length of the lower surface of a peripheral wall forming a cylindrical form face, and a push plate 4 which is interposed in the opening part 2 and blocks the opening part 2. Reinforcing plates 5 and 6 are protruded inwardly and spaced from each other, on the inner face of a ceiling part 3a at both ends of the core form 3 and the inner faces of both ends of a side wall 3b at both sides of the core form 3, respectively. An elliptic hole 7 with the upper part sloping outwardly is formed in the reinforcing plate 6. A guide plate 8 for extension/contraction is protruded upward on both ends of the push plate 4, and a connecting pin 9 provided at both sides of the guide plate 8 is fitted to the elliptic hole 7 in a freely sliding manner. In addition, link mechanisms 10a and 10b lift the push plate 4 up/down and extend/contract the core form 3 in an interlocking action with the push plate 4, and are installed on the core form 3 and both end sides of the push plate 4, respectively. The link mechanism 10a is connected to a tubular shaft 18 inserted, in a freely sliding manner, into the outer peripheral face of one of the end sides of a shaft bar 17, while the other link mechanism 10b is connected to the other end side of the shaft bar 17. The tubular shaft 18 is moved in an opposite direction to the shaft bar 17 by moving the shaft bar 17 back/forth, and setting the tubular shaft 18 in an interlocking action with the shaft 17. COPYRIGHT: (C)2004,JPO
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