Tool detecting apparatus

• US 5,029,097 A
• Filed: 06/01/1989
• Issued: 07/02/1991
• Est. Priority Date: 06/03/1988
• Status: Expired due to Term

• Current Assignee: Hitachi VIA Mechanics Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Seiko Limited
• Inventors: Otani, Tamio, Kanaya, Yasuhiko, Michigami, Norio
• Primary Examiner(s): Smith, Jerry
• Assistant Examiner(s): Gordon, Paul
• Application Number:
  US07/360,094
• Time in Patent Office: 761 Days
• Field of Search: 364/474.35, 364/474.28, 364/474.37, 364/513, 364/559, 364/563, 356/373, 356/375, 356/376, 356/384, 901/47, 382/8, 382/14, 382/46
• US Class Current: 700/193
• CPC Class Codes: G05B 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/37345 Dimension of workpiece, diameter
• CPC Class Codes: G05B 2219/49177 Runout, eccentricity, unbalance of tool or workpiece
• CPC Class Codes: G05B 2219/50294 Tool offset length by going to a reference and recording distance

Abstract

A tool detecting apparatus including a first detection part having a plurality of arrayed light-receiving elements receiving a beam of light passing around a tool placed in an optical path and a memory circuit for sequentially storing binary signals corresponding to the outputs of the light-receiving elements scanned at a predetermined time interval thereby updating its previous contents, and at least one of a second detection part, third detection part and a fourth detection part. The second detection part includes a state detection circuit and a timing circuit while the third detection part includes a holding circuit and an arithmetic circuit. The fourth detection part includes another arithmetic circuit.

Claims

1. A tool detecting apparatus comprising:

first detecting means including a plurality of arrayed light-receiving elements receiving a beam of light passing around a tool placed in an optical path, and memory means for sequentially storing a group of binary signals corresponding to the outputs of said light-receiving elements scanned at a predetermined time interval thereby updating its previous contents; and

detecting/arithmetic processing means for detecting said tool in response to an output of said first detecting means, said detecting/arithmetic processing means including at least one of second, third and fourth detecting means,

said second detecting means including means for detecting displacement of a tool-holding spindle from its original position thereby detecting the current position of said spindle, means for detecting, on the basis of the contents of said memory means, the timing of detection of a predetermined portion of said spindle by said light-receiving elements, and means for calculating, on the basis of the position of said spindle detected at said detection timing, a correction value required for correcting the amount of displacement of said spindle at the time of machining,

said third detecting means including means for holding the maximum number of said light-receiving elements covered by the shadow of said tool while said tool makes one revolution, and means for calculating the diameter of said tool on the basis of the held maximum number of said shaded light-receiving elements, and

said fourth means including means for detecting a most significant and a least significant bit position where a level change occurs in the binary signals sequentially stored in said memory means and calculating the amount of eccentricity of said tool on the basis of the difference between said positions.

2. A tool detecting apparatus according to claim 1, wherein said detecting/arithmetic processing means includes said second detecting means.

3. A tool detecting apparatus according to claim 1, wherein said detecting/arithmetic processing means includes said third detecting means.

4. A tool detecting apparatus according to claim 1, wherein said detecting/arithmetic processing means includes said fourth detecting means.

5. A tool detecting apparatus according to claim 1, wherein said detecting/arithmetic processing means includes said second and third detecting means.

6. A tool detecting apparatus according to claim 1, wherein said detecting/arithmetic processing means includes said second and fourth detecting means.

7. A tool detecting apparatus according to claim 1, wherein said detecting/arithmetic processing means includes said third and fourth detecting means.

8. A tool detecting apparatus according to claim 1, wherein said detecting/arithmetic processing means includes said second, third and fourth detecting means.

9. A tool detecting apparatus according to claim 1, wherein said correction value calculating means includes means for previously setting an amount of reference displacement of said spindle from its reference position when said light-receiving elements are traversed by the shadow of said predetermined portion of said tool held on said spindle in a relation satisfying machining specification requirements, and arithmetic means responsive to said timing detecting means for comparing the value of the position of said spindle detected by said spindle position detecting means with said reference displacement of said spindle and generating the result of comparison as said correction value.

10. A tool detecting apparatus according to claim 1, wherein said tool diameter calculating means calculates the diameter of said tool on the basis of the maximum number of said shaded light-receiving elements and the distance between said arrayed light-receiving elements.

11. A tool detecting apparatus according to claim 1, wherein said third detecting means further includes means for previously setting the diameter of said tool and means for comparing the output of said tool diameter calculating means with the set value of said tool diameter.

12. A tool detecting apparatus according to claim 1, wherein said tool eccentricity calculating means further includes means for previously setting the diameter of said tool and means for comparing said calculated amount of eccentricity of said tool with the set value of said tool diameter.