| 摘要 |
PCT No. PCT/GB88/00610 Sec. 371 Date Jan. 19, 1990 Sec. 102(e) Date Jan. 19, 1990 PCT Filed Jul. 25, 1988 PCT Pub. No. WO89/01193 PCT Pub. Date Feb. 9, 1989.In CNC machining, the radius of the circle described by a tool tip has been set manually using a separate setting machine. The present invention allows such a radius to be set automatically. A rotary datuming touch trigger probe has internal and external cylindrical datum surfaces 40 and 41. Threee piezo-electric crystals 47a, 47b, and 47c are mounted between a mounting member 43 for the cylindrical surfaces and a collar 44 fixed to a machining table 46. The tip of a tool forming part of a boring head is brought into engagement with the surfaces by driving the tool along the U-axis and when engagement occurs it is sensed by the piezo-electric crystals which send a signal to a computer. The procedure is repeated with the tool tip 180 DEG and 270 DEG around the cylindrical surfaces from its original position allowing the computer to determine the radius of the tool tip relative to the axis of the datum surfaces. Other forms of rotary datuming probes are also described. |
