| 摘要 |
The device for releasably securing stationarily a finely angularly adjusted shaft in an instrument with respect to the body thereof includes a cylindrical flange formed in the body and rotatably supporting the shaft therein and provided with a plurality of cut-out portions arranged circumferentially spaced from each other, a rotatable clamping ring rotatably fitted around the flange and having in its periphery wedge-shaped recesses the arrangement of which corresponds to that of the cut-out portions, and clamping members each received in the respective cut-out portion and wedge-shaped recess aligned therewith so that each clamping member is interposed between the outer surface of the shaft and the respective recess, thereby permitting the shaft to be releasably secured stationarily with respect to the body by rotating the clamping ring in one direction in which each clamping member is urged against the shaft by the wedge-shaped recess, while the shaft is released to freely rotate when the clamping ring is rotated in the opposite direction. According to the present invention, the device comprises a pivot pin arranged at the side of the respective cut-out portions preferably at the side opposite to the direction of rotation of the clamping ring for the clamping action of the shaft, and the respective clamping member is formed with a ear portion having an opening formed therein which is pivotally engaged with the respective pivot pin so that the clamping member is positively prevented from being rollingly rotated in the cut-out portion during the rotation of the clamping ring thereby preventing undesired rotation of the shaft which might be caused by the rotation of the clamping members at the moment the shaft is secured stationarily by the clamping members during the rotation of the clamping ring. The clamping members may be formed integrally in a clamping member supporting ring. A rotation preventing ring having at least a stopper recess is provided around the cylindrical flange and the stopper recess is engaged with stopper lug(s) formed in the body so as to stationarily secure the rotation preventing ring with respect to the body. The rotation preventing ring is preferably interposed between the rotatable clamping ring and a C-ring secured to the shaft for preventing the removal of the clamping ring from the shaft. The rotation of the clamping ring is positively prevented from being transmitted to the C-ring by the interposition of the rotation preventing ring thereby preventing rotation of the shaft.
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