The thickness in the width direction of a pair of side wall sections 4 is made as uniform as possible. In use, a load is applied to the pivot 3 from the side of the first and second connecting sections 5, 6 which connect the pair of side wall sections 4. A crimped section 13a is formed on the outer periphery at the opposite end surfaces of the pivot 3b, on the half on the side of the connecting sections 5, 6. Therefore, the outer peripheral surface of the opposite ends of the pivot 3b comes into contact with the inner peripheral surface of the through hole 11 on the load support side. Consequently, the load is sufficiently supported by the contact surface, and even after being used for a long time of period, lost motion is prevented from occurring on the support section at the opposite ends of the pivot 3 with respect to the pair of side wall section 4.