Tire tread buffing apparatus and method

A method for manufacturing a retreaded tire including buffing a tire casing, such method comprising:

• mounting a tire casing to be retreaded so that the tire casing may be rotated about a central axis;
• taking an outer measurement of the tire casing indicative of the distance from the central axis to an outer surface of the tire casing;
• moving a cutting device into contact with the tire casing to remove rubber from the tire casing through a series of iterative cutting passes of the cutting device over the tire casing;
• acquiring electrical signals indicative of the amount of rubber remaining as a result of the difference between a cutting depth of a cutting device and a resulting outer measurement of the tire casing;
• determining a target outer measurement for the tire casing to be retreaded;
• determining an offset for at least one of the last of the iterative cutting passes made on the tire casing such that the offset is employed to alter the position of the cutting device and permit the tire casing to have an outer measurement that matches substantially the target outer measurement;
• applying and curing a tread to the tire casing in a manner to attach such tread and generate a retreaded tire.

A buffing machine for removing rubber from a tire casing to produce a tire casing with a predetermined target circumference, the buffing machine adapted to rotatably mount the tire casing onto a rim, the rim associated with a rim motor arranged to rotate the rim, the buffing machine comprising:

• a cutting device including an electric motor and disposed on a moveable arm such that the cutting device is adapted to selectively engage a tire casing to be retreaded at a cutting depth;
• a position sensor associated with the moveable arm and disposed to provide a cutting depth signal indicative of the position of the cutting device in a radial direction from a central axis about which the tire casing is rotatable, such position signal also being disposed to provide a circumference signal indicative of an initial circumference of the tire casing;
• and,
• an electronic controller connected to the position sensor and the cutting device, the electronic controller being disposed (a) to receive and process cutting depth signals and the initial circumference signal, (b) to move the cutting device into contact with the tire casing at cutting depth while receiving an electrical signal indicative of the amount of rubber being left behind after the cutting device has engaged the tire casing, and, (c) based on a final target outer measurement for the tire casing, to determine a subsequent cutting depth offset which is derived from the electrical signal indicative of the amount of rubber being left behind after the cutting device has engaged the tire casing such that the cutting device may be moved to a cutting dept that will result in a final outer measurement of the tire casing that substantially corresponds to the final target outer measurement.