Tool life monitoring and tracking apparatus

• US 4,351,029 A
• Filed: 12/05/1979
• Issued: 09/21/1982
• Est. Priority Date: 12/05/1979
• Status: Expired due to Term

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Maxey, Robert E. L., Brecker, James N.
• Primary Examiner(s): Ruggiero, Joseph F.
• Application Number:
  US06/100,674
• Time in Patent Office: 1,021 Days
• Field of Search: 364/474, 364/475, 364/105, 364/119, 364/506, 364/511, 364/483, 364/550, 340/679, 340/680, 318/571, 318/563, 318/565, 318/39, 318/650, 318/561, 409/145, 409/148, 409/150, 409/151, 409/153, 409/154, 409/156, 409/80, 408/9, 408/10, 408/11, 408/12, 408/13, 408/16, 324/142, 324/76 A, 73/104, 73/105, 73/117, 73/117.3, 73/117.4, 73/116
• US Class Current: 702/34
• CPC Class Codes: G01N 3/58 Investigating machinability by cutting tools; Investigating the cutting ability of tools
• CPC Class Codes: G05B 19/4065 Monitoring tool breakage, life or condition
• CPC Class Codes: G05B 2219/37252 Life of tool, service life, decay, wear estimation
• CPC Class Codes: Y10T 408/172 Responsive to Tool

Abstract

Net power consumed by one or more tools, continuously or intermittently is totalized and compared with a predetermined energy limit characterizing the life expectancy of a tool for optimum and safe use on a machine tool. Digital and computer techniques are used in order to keep track of the usage of the various tools within their respective life expectancies.

Claims

1. A system for monitoring tool life on a machine tool having at least one operative tool thereon, comprising:

means for instantaneously and recurrently deriving a measuring signal characteristic of power consumed by said machine tool for the purpose of relative motion between said workpiece and said tool;

said measuring signal deriving means being operable in one of an idle position mode and a working position mode of said tool relative to said workpiece;

means for combining an idle position measuring signal and a working position measuring signal for deriving a signal indicative of net power consumed by said tool;

means for integrating said indicative signal as a function of time for obtaining a past history characteristic signal;

means responsive to said integrating means for comparing said characteristic signal with a reference signal representative of the life expectancy of said tool.

2. The system of claim 1 with said measuring signal deriving means comprising voltage to frequency converter means for providing a pulse train having a pulse rate characteristic of said measuring signal;

counter means for counting pulses in said pulse train during a sample time interval, and offset storage means operative to store a count from said counter means when in the idle position mode;

said combining means being operable to subtract said idle position count from a count derived from said counter means in the working position mode.

3. The system of claim 2 with means responsive to said power signal indicative means and to a predetermined maximum net power limit for setting an alarm when said net power limit is exceeded.

4. The system of claim 3 with said alarm setting being effective when said net power limit has been exceeded during a predetermined minimum time interval.

5. The system of claim 2 with means responsive to said comparing means for providing a command signal for changing said tool when the threshold of said reference signal has been reached by said life status signal.

6. The system of claim 5 with means responsive to said integrating means for providing an indication of excessive energy being used with said tool.

7. The system of claim 5 with means for storing an indication of said life status signal operative after and before an interruption in the use of said tool.