Hand-tight drill chuck with lock

A hand-tight drill chuck with a lock, comprising:

• a drill body,
• a ring member,
• a clamping jaw, and
• a self-locking structure,
• wherein the ring member has an internal thread while an outer side of the clamping jaw has a thread, the ring member and the clamping jaw are threadedly connected, the self-locking structure comprises a ring of teeth, a ring of the teeth is arranged on the drill body or arranged on a component fixed to the drill body;
• wherein the self-locking structure further comprises an elastic piece having an arcuate portion, the elastic piece is arranged on the ring member, both ends of the arcuate portion are restricted, the elastic piece is provided with a lock portion and a groove or a protrusion that cooperate with a ring of the teeth between the two ends of the arcuate portion, the drill chuck is provided with a rotation sleeve, and the rotation sleeve is provided with a control structure so that the self-locking structure is in a self-locking state or an unlocked state,
• wherein the control structure comprises a metal member having an elastic portion between two ends which are inserted into an inner wall of the rotation sleeve, the elastic portion of the metal member is provided with a protrusion or groove matched with the groove or the protrusion of the elastic piece, when the groove or the protrusion of the elastic piece tightly withstands against and is engaged with the protrusion or the groove of the metal member by elasticity, the drill chuck is in a self-locking state.