Detection device and method for detecting objects subject to cyclic or repetitive motion

• US 7,732,797 B2
• Filed: 09/07/2005
• Issued: 06/08/2010
• Est. Priority Date: 09/08/2004
• Status: Active Grant

• Current Assignee: Renishaw PLC
• Original Assignee: Renishaw PLC
• Inventors: Bell, Colin Timothy, Davies, William Kenneth, Stimpson, Victor Gordon, Maxted, Paul
• Primary Examiner(s): Sohn; Seung C
• Application Number:
  US11/659,848
• Publication Number:
  US 20070217673A1
• Time in Patent Office: 1,735 Days
• Field of Search: 250/559.4, 250/559.29, 250/559.12, 250/559.14, 356/511, 356/638, 356/640, 356/625, 356/602, 356/623, 356/614, 324/642, 382/152
• US Class Current: 250/559.4
• CPC Class Codes: B23Q 17/2442 of a tool
• CPC Class Codes: G05B 2219/37233 Breakage, wear of rotating tool with multident saw, mill, drill

Abstract

A device and method for detecting the presence or absence of an object which has repetitive motion are disclosed comprising, a receiver for receiving a signal from the object, and circuitry for determining the presence or absence of the object to be detected, wherein the circuitry records the signal from the receiver as a pattern of data during at least part of the repetitive motion of the object, compares the data with a previously recorded data pattern and, produces an output signal based on the comparison. The signal may be received during discrete time intervals, and may be light which can be transmitted with varying intensity. The circuitry may determine the value of signal received at a receiver and produce a binary value. The signal received at the receiver can be reflected from the object to be detected.

Claims

1. A device for detecting the presence or absence of an object which has repetitive motion, the device comprising

a receiver for receiving a signal reflected or emitted from the object;

and

circuitry for determining the presence or absence of the object to be detected, characterised in that

the circuitry is configured to record the signal from the receiver as a pattern of data during at least part of the repetitive motion of the object during an inspection of the object, and to compare the data with a data pattern recorded during a previous repetitive motion of the object during the same inspection of the object, and to produce an output signal based on the comparison.

2. A device according to claim 1 wherein, the signal is received during discrete time intervals.

3. A device according to claim 1 wherein, the signal is light.

4. A device according to claim 3 wherein, the light is from a transmitter and the receiver receives light from the transmitter in order to produce the said signal.

5. A device according to claim 1 wherein, the circuitry determines the value of signal received at the receiver and produces a binary value.

6. A device according to claim 5 wherein, if the signal reflected from the object exceeds a predetermined threshold then the value of the data is recorded as a 1.

7. A device according to claim 1 wherein, when the previously recorded data has a correlating relationship with the pattern of data then a tool found signal is issued by the circuit.

8. A device according to claim 1 wherein, when the previously recorded data is no longer matched by the pattern of data then a tool found signal is issued by the circuit.

9. A device according to claim 3 wherein, the transmitted light is transmitted with varying intensity.

10. A method for detecting the presence or absence of an object which has repetitive motion, the method comprising the steps of:

receiving a signal reflected or emitted from the object at a receiver;

recording the signal from the receiver as a pattern of data during at least part of the repetitive motion of the object during an inspection;

comparing the data with a data pattern recorded during a previous repetitive motion of the object during the same inspection of the object; and

producing an output signal based on the comparison.

11. A method according to claim 10 wherein, the pattern of data is a binary pattern.

12. A method according to claim 11 wherein, if the signal reflected from the object exceeds a predetermined threshold then the value of the data is recorded as a 1.

13. A method according to claim 10 wherein, when the previously recorded data has a correlating relationship with the pattern of data then a tool found signal is issued by the circuit.

14. A method according to claim 10 wherein, the signal is light and the light has varying intensity.

15. A device for detecting the presence or absence of an object which has repetitive motion, the device comprising:

a receiver for receiving a signal from the object; and

circuitry for determining the presence or absence of the object to be detected,

characterized in that

the circuitry records the signal from the receiver as a pattern of data during at least part of the repetitive motion of the object during an inspection of the object and produces an object detection output signal either when the pattern matches a pattern recorded during a previous repetitive motion of the object during the same inspection of the object or when the pattern no longer matches the pattern.

16. A detection device for detecting the presence or absence of an object, the device comprising a light transmitter and a light receiver positioned relative to the light transmitter to receive light reflected by the object, comprising:

circuitry for determining the presence or absence of the object to be detected, the circuitry being configured to record the signal from the receiver as a pattern of data during at least part of the repetitive motion of the object during an inspection of the object, and to compare the data with a data pattern recorded during a previous repetitive motion of the object during the same inspection of the object, and to produce an output signal based on the comparison,

transmitted light being transmitted with varying intensity.

17. A detection device according to claim 16 wherein, the varying intensity is a variation between no light and full light transmitted by the light transmitter.

18. A detection device according to claim 16 wherein, the light is transmitted periodically.

19. A detection device according to claim 16 wherein, the period is approximately 10-500 kHz.