Provided is a feeler for workpieces being machined, including a rocking arm configured to feel the workpiece, a first sensor configured to measure the position of the rocking arm and at least one additional sensor operatively connected to the rocking arm and configured to detect external perturbations acting on the feeler.

Device for controlling the sharpening state of a blade (2) having a cutting edge (20) delimited by two sides (21, 22) converging towards a plane (X) that contains the cutting edge itself. The device comprises two control surfaces each of which is in contact with a corresponding side (21, 22) of the cutting edge (20) and is connected with a transducer (R4), which produces an electrical displacement signal (S4) proportional to a displacement of the control surface with respect to said plane (X). Furthermore, the device comprises a processing unit (E) that receives said displacement signals (S4) and compares them, emitting an error signal if the comparison produces a value that exceeds a predetermined limit. The control surfaces are the surfaces that delimit an external groove (40) of a roller (4) that is free to translate along an axis (A4) perpendicular to said plane (X) and spaced from the blade (2) by an amount such that said cutting edge (20) passes in said groove (40).

Device for controlling the sharpening state of a blade (2) having a cutting edge (20) delimited by two sides (21, 22) converging towards a plane (X) that contains the cutting edge itself. The device comprises two control surfaces each of which is in contact with a corresponding side (21, 22) of said cutting edge (20) and is connected with at least one transducer (R1, R2, R4), which produces an electrical displacement signal (S1, S2; S4) proportional to a displacement of the control surface with respect to said plane (X). Furthermore, the device comprises a processing unit (E) that receives said displacement signals (S1, S2, S4) and compares them, emitting an error signal if the comparison produces a value that exceeds a predetermined limit. The processing unit is connected to means (101, 102) for supporting and moving sharpening means (100).

Systems and methods are provided for detecting contact between a manufacturing apparatus and an article being worked upon by the manufacturing apparatus. Vehicles that include the article are also provided. The system includes the manufacturing apparatus configured to perform a process on the article, a signal transmitter configured to apply an input signal to the article with during the process such that the input signal is conducted through the article, a signal receiver configured to monitor a first component of the manufacturing apparatus to detect conduction of the input signal through the first component with during the process, and a signal processor configured to determine whether contact has occurred between the first component of the manufacturing apparatus and the article based on the detection of the input signal by the signal receiver.