MANDRIN AUTO-SERREUR POUR PERCEUSES OU APPAREILS ANALOGUES

Ce mandrin comprend un manchon cylindrique (10) qui se fixe axialement à l'arbre de la perceuse, une bague (29) principalement conique et munie de lobes (32) qui s'accouplent axialement et solidairement au manchon, une douille (23) qui centre l'outil et un ressort (26), la douille et le ressort étant logés dans la cavité (19) du manchon, et une cage (34) présentant un alésage central (41) qui reçoit l'outil et des trous radiaux (44) recevant des mors ou billes (35). La cage peut se déplacer axialement par ressort au manchon et elle peut être fixée à la bague (29) de façon démontable au moyen d'une bague (43) qui se visse sur un filetage (38) de la cage qui émerge de la bague principale. A self-gradually locking chuck for drills or similar devices particularly suitable for portable drills used in surgery. It includes a cylindrical sleeve which can be coaxially fixed to a rotating shaft, a ferrule having a conical section provided internally with lobes, a cylindrical portion at one of its ends for engagement with said sleeve and a cylindrical portion at the other end. A first mounting, perforated longitudinally by a hole, includes a central portion having locking jaws which are movable in holes in a direction convergent upon the axis of the chuck and two second mountings opposite to the central body. A spring and centering device are provided. A cylindrical ferrule is threaded to a part of the first mounting as it projects from the first-mentioned ferrule. The first mounting and ferrule move axially in relation to each other and in relation to the cylindrical sleeve in which the ferrule can be releasably secured to the cylindrical ferrule by a retaining device. The second mountings are releasably secured to the sleeve by a retaining device.