Broach sharpening machine

A broach sharpening machine, of the type comprising a first sharpening slide arranged to impart, to a grinding wheel supported by it, a movement having a constant stroke away from and towards said broach in a direction transverse to the longitudinal axis of the broach, a second and a third slide mobile along two axes which form a contained angle, the axis of movement of said second slide being parallel to said longitudinal axis, and a feeler unit arranged to determine the position of said grinding wheel relative to each tooth of said broach in succession, characterised in that said third slide supports both said feeler unit and said first slide, and that said feeler unit comprises an articulated parallelogram constituted by a frame rotatable relative to said third slide about an axis perpendicular to the broach axis and to the axis of movement of said second slide, a drag link, and two resilient cranks which connect said drag link and said frame together;

• the feeler unit also comprising first means for detecting the movements of said frame about its axis of rotation, and second means for detecting the axial movement of said drag link, this latter comprising coupling means arranged to engage with the teeth of said broach positively and in succession, resilient means being connected to said frame in order to move said coupling means towards said broach teeth.