Patent ID: 8469640

Claim:
A processing machine, comprising: a casing; a tool-holder spindle which extends along a first axis; a drive motor for driving the tool-holder spindle; and a drive mechanism which is for the tool-holder spindle and which mechanically connects the drive motor to the tool-holder spindle, the drive mechanism comprising: a first drive member for rotating the spindle about the first axis thereof relative to the casing; a second drive member for driving the spindle in translation along the first axis thereof relative to the casing, the second drive member being screwed onto a threaded portion of the spindle in such a manner that the spindle advances or returns along the first axis thereof in accordance with the relative rotational speed between the first drive member and the second drive member; and a clutch which has a return configuration for the spindle, in which the second drive member and the drive motor are disengaged, and an advance configuration for the spindle, in which the second drive member and the drive motor are engaged, wherein the clutch comprises: a rotary engagement member which is connected in terms of rotation to the second drive member, the rotary engagement member being movable in terms of rotation about a second axis relative to the casing; at least a first key which is movable relative to the rotary engagement member between a first position for connecting the rotary engagement member to the drive motor and a second position for disengaging the rotary engagement member; and at least a second key which is movable relative to the rotary engagement member between a third position for connecting the rotary engagement member to the casing and a fourth position for disengaging the rotary engagement member, the first key being in the first position and the second key being in the fourth position when the clutch is in the advance configuration for the spindle, the first key being in the second position and the second key being in the third position when the clutch is in the return configuration for the spindle.