The device of the tripod stand

In the system of the vertical axis, the upper supporting surface of the bronze sleeve is a guide. A steel ring attached to the base of the visual pipe glides along it. For centering is a steel cylindrical axis, on the lower part of which a safety nut closed by a cap is screwed up. There is a gear between the sleeve and the stand, which is included in the ending with an endless leading screw. Through the ring the gear is pressed to the sleeve springs. The springs are designed so that the moment of friction force arising from the rotation of the gear relative to the sleeve s is twice as much as the friction force between the steel ring and the supporting surface of the sleeve. Therefore, with a gross hoverning of the level on the rail, the pipe rotates with the gear quite easily and is installed in the right direction quite reliably without a clamping screw. When the leading screw is rotated, the gear remains motionless, and the visual pipe slowly rotates around the vertical axis. In some designs of levels, an elevated screw is used, with which you can raise or lower one of the ends of the pipe or level. Elevation screws require a small pitch of threads and therefore wear out quickly. Recently, they are performed in the form of a mobile wedge. When rotating the screw head, the movable wedge moves. At the same time, he moves the pin, which, in turn, transfers movement to the tide of the body of the visual pipe. When the screw is unscrewed, the spring moves the wedge to the right and the pin drops down. Correctioning screws of levels and nets of threads: correctional screws serve to bring the main geometric elements of the tool in conjugation, determined by this geometric scheme. In modern tools, as a rule, the preservation of the perpendicularity of the horizontal axis of the rotation of the pipeline of the vertical axis of the rotation of the tool guarantees the manufacturer. Therefore, pipe stands are not supplied with correctional screws. Consider the correctional screws of the levels and nets of threads.