DISPOSITIVO PER LA PERFORAZIONE A PERCUSSIONE

摘要

A drill chuck assembly for a percussion or hammer drill in which the chuck body is mounted on a rotatable drill spindle and the hammer impact is transmitted by a ram through the spindle to the bit retained in the chuck. A coupling ring surrounding a coaxial portion of the chuck body and the spindle has three angular positions in one of which the chuck body can be withdrawn axially from the spindle and in the second and third of which the body is retained on the spindle. Formations between a shoulder of the spindle and the coupling ring come into play in the second position to permit limited axial displacement of the chuck body on the spindle and are effective in the third position to prevent such axial displacement.