Mechanical open-ended spanner

摘要

The mechanical open-ended spanner is used for releasing or tightening polygonal screws or nuts. It remains on the screw during the entire screwing operation and undergoes a type of idling when pulled back against the screwing direction. Hooks (A) which can only tilt forwards (+x) are made in the inner sides of the spanner head (see Fig. 1) of half-round shape. These hooks are kept constantly upright or are pressed (-x) against the screw by springs (B). If pressure is exerted in screwing direction (+y), the screw is squeezed from several sides between the hooks so that it sticks in the mechanism and turns with it. If the spanner is moved against the screwing direction (-y), the hooks tilt away forwards (+x) and slip over the screw. The main possible use is in all technical areas where nuts or screws have to be tightened or released. The invention is used in particular in the case of screws which are difficult to reach and are provided with a long threaded part or are damaged ("turned half-round"), since these labour-intensive screwing operations are considerably reduced. <IMAGE>