Tool for accurate rotation of inserted screw - has scale fixed to tool and marker on screw and on workpiece respectively

摘要

A screw tool for application of a desired tension to the shaft of a screw inserted in a workpiece consists of an attachment on the screw head or nut suitable for rotation by a corresponding lever arm. The arrangement enables the screw head to be rotated accurately through a defined angle. The tool has a disc with a scale coaxial with the attachment rotation axis and an indicator marking to be read against the scale. Scale and marking are mutually relatively rotatable about the attachment axis. The scale and marking are attached to the tool and the workpiece respectively. The disc carrying the scale can be clamped via a spring pressing a bolt against the periphery of the disc.