Holder 11, in order for plural insertion components 33 and connected section 31a and 32a to leave being first setting distance, when the plural arm components it has with 31 which are formed and 32, the annular section 33b which becomes the annular form which leaves being second setting distance from the medial axis of the perforation hole 33d is formed in insertion component 33, optional position and arm component connected section 31of a 31 and 32 and 32a are connected from among all amounts of annular section 33b of insertion component 33, position and arm component 31 of desire of annular section 33b of insertion component 33In order, to become a state where connected section 31of a 32 and 32a have been connected, as arm component 31 and 32 becomes movement possible inside this contact surface of the head surface, position and arm component while a state where connected section 31of a 31 of desire of annular section 33b of insertion component 33 and 32 and 32a have been connected is maintained, with normal direction of the head surface connected section 31a and 32a arm component 31 and 32 features that it becomes time motion possible with normal direction of the head surface by time motion doing vis-a-vis annular section 33b.ホルダ11であって、複数の挿入部材33と、連結部31a、32aが第一設定距離で離れるように形成されている複数のアーム部材31、32とを備え、挿入部材33には、貫通孔33dの中心軸から第二設定距離で離れる円環形状となる円環部33bが形成されており、挿入部材33の円環部33bの全部分の内から任意の位置とアーム部材31、32の連結部31a、32aとが連結されると、挿入部材33の円環部33bの所望の位置とアーム部材31、32の連結部31a、32aとが連結された状態となるように、頭部表面の当接面内でアーム部材31、32が移動可能となるとともに、挿入部材33の円環部33bの所望の位置とアーム部材31、32の連結部31a、32aとが連結された状態を維持したまま、頭部表面の法線方向で連結部31a、32aが円環部33bに対して回動することにより、頭部表面の法線方向でアーム部材31、32が回動可能となることを特徴とする。
