| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a wrench with versatility capable of coping with fastening or loosening of a tool to be fastened of an arbitrary size by a simple using method.SOLUTION: A wrench is used for fastening or loosening a tool to be fastened having a square outer shape. The wrench includes a support board having an opening to accept the tool to be fastened and at least two wrench pieces applied to at least two precipitous side surfaces of the tool to be fastened which face the opening of the support board. The wrench pieces are arranged along the circumferential direction of the opening of the support board and are opened/closed in the circumferential direction of the opening with fulcrums as centers. The plurality of wrench pieces are opened/closed in the circumferential direction of the opening synchronously with each other and adhered/separated to/from the side surfaces of the tool to be fastened.</p> |
