Machine for machining workpieces with cutting teeth, especially saw blades

A machine for machining workpieces (10) which have cutting teeth (12), especially saw blades, comprising

• a machine bed (20) on which a pivot axis (A) is fixed,
• a guide body (22) which defines a lift axis (D) extending transversely of the pivot axis (A),
• a reciprocating slide (24) which is guided on the guide body (22) for reciprocating along the lift axis (D),
• a saddle (26) which defines a spindle axis (E) extending transversely of the lift axis (D) and is guided on the reciprocating slide (24) for infeeding motion,
• a tool spindle (28) which is supported on the saddle (26) so as to be driven in rotation about the spindle axis (E) and is adapted to receive a tool (30) adapted to be driven in rotation,
• a workpiece slide guide means (40) which extends transversely of the pivot axis (A) and defines an adjustable angle with the lift axis (D),
• a workpiece slide (42) which is guided on the workpiece slide guide means (40) and defines a central plane (G), at right angles to the pivot axis (A), together with a workpiece support (44) integrally formed on the workpiece slide (42),
• a feeler means (60) which determines the distance of the cutting teeth (12) of the workpiece (10) from the workpiece support (44), adopting a measuring position, at least at times, which is reached by the tooth tip (18) of a cutting tooth (12), oriented in the direction of the pivot axis (A), of a workpiece (10) received in the workpiece support (44) when the workpiece slide (42) is shifted in the direction of the pivot axis (A) from a loading position remote from said pivot axis (A),
• an advance means (50) including an advance finger (58) adapted for intermittent engagement with a respective tooth face (14) so as to advance the same into a desired position at which it lies in a plane including the pivot axis (A),
• a numerical control means (80) for controlling movements of the saddle (26) and the workpiece slide (42) in response to signals from the feeler means (60) characterized in that
• the feeler means (60) comprises a barrier (70) the length(L) of which, as measured in said central plane (G) transversely of the workpiece slide guide means (40), is greater than the greatest tooth pitch (T) occurring of workpieces (10),
• the control means (80) is programmed such that the feeler means (60) becomes active before the advance means (50) so as to scan the tooth tip (18) of a cutting tooth (12) irrespective of the position of the corresponding tooth face (14), and
• the control means (80) furthermore is programmed such that the workpiece (10) is scanned once more at the tooth tip (18) of the cutting tooth (12) whose tooth face (14) is in the desired position, and the position of the workpiece slide (42) is corrected if said tooth tip (18) does not lie on the pivot axis (A).