| 摘要 |
A tilt adjustment device for use as part of a boom stand for supporting lights, microphones and the like, or as an adaptor for converting an existing stand into a boom stand. The device includes first and second fixtures adapted to be coupled respectively to an upright tubular member of the stand and a boom arm. One of the fixtures includes a pair of arms and the other includes a boss which is received between the arms and which has respective end faces confronting corresponding inner faces of the arms. The fixtures are coupled together for pivotal movement about an axis extending between the arms through the boss for permitting tilting of the boom arm with respect to the support member. A shaft extends along the axis and clamping washers are provided on the shaft for drawing the respective arms inwardly and clamping them against end faces of the boss for securing the boom arm in a selected angular position. Friction washers disposed between end faces of the boss and the confronting faces of the arms are restrained against turning with respect to the boss and have friction faces that bear against the arms. Each washer has a relieved annular area around the shaft and a corresponding raised area around its marginal portion so that frictional forces engendered between the washer and the arm react at locations spaced radially from the shaft for resisting slipping of the fixtures with respect to one another when a load is applied to the boom arm member. |
