Device for tightening or loosening screws or nuts

摘要

The device has the function of a spanner. It is suitable for different head sizes and has a ratchet action, i.e. it is not necessary to remove it from the head during slackening. This is achieved in that the screw (5) is surrounded by a self-locking strap loop (2) which draws together during clockwise rotation and opens during anticlockwise rotation. The drawing-together is supported by rolling up on the curved face (6). The self-locking is brought about substantially by the nose (8) having a small radius of curvature. The strap loop is composed of elastic material on the side facing the screw and of high-strength material having a high modulus of elasticity on the outside. The fastening points of the strap loop lie at the points (3) and (4), and possibly also at the nose (8). <IMAGE>