System and method for evaluating a tipping moment experienced by a movable press member

• US 6,556,928 B2
• Filed: 06/10/2002
• Issued: 04/29/2003
• Est. Priority Date: 11/03/1998
• Status: Expired due to Term

• Current Assignee: The Minster Machine Company (Nidec Corporation)
• Original Assignee: The Minster Machine Company (Nidec Corporation)
• Inventors: Schoch, Daniel A.
• Primary Examiner(s): Noland, Thomas P.
• Application Number:
  US10/166,551
• Publication Number:
  US 20030018409A1
• Time in Patent Office: 323 Days
• Field of Search: 702/41, 702/113, 702/189, 702/190, 100/99, 100/48, 100/43, 738/625.41, 738/625.5, 738/659, 700/206
• US Class Current: 702/41
• CPC Class Codes: B30B 15/28 Arrangements for preventing distortion of, or damage to, presses or parts thereof
• CPC Class Codes: G05B 19/4065 Monitoring tool breakage, life or condition
• CPC Class Codes: G05B 2219/37435 Vibration of machine
• CPC Class Codes: G05B 23/0232 based on qualitative trend analysis, e.g. system evolution

Abstract

A system is provided for monitoring the operation of a press machine over a series of press running cycles. A plurality of press operating events associated with the operation of the press machine are defined. Each press operating event has a modifiable control function associated therewith. An arrangement of accelerometers measures the press machine vibrational activity associated with each press operating event that occurs during the series of press running cycles. A processor processes the vibration measurements associated with the press operating events to identify the presence of a vibration trend therein meeting a defined trending criteria. A controller is responsive to trend identification signals generated by the processor for modifying the respective control function of each press operating event which is associated with identification of the vibration trend.

Claims

1. A method of monitoring the operation of a press machine having an operatively movable press member, said method comprising the steps of:

defining at least two load measurement locations associated with said movable press member;

providing a measure of the load developed within said movable press member at each respective one of said at least two load measurement locations and generating load measurement signals representative thereof;

determining a tipping moment experienced by said movable press member based upon the generated load measurement signals; and

evaluating the determined tipping moment relative to a predefined tipping moment severity level.

2. The method as recited in claim 1, wherein the load measurement providing step further includes the step of:

providing a respective load sensor coupled to said movable press member at each respective one of said at least two load measurement locations.

3. The method as recited in claim 2, wherein said movable press member includes at least one of a press machine slide and a press machine stripper plate.

4. The method as recited in claim 1, wherein the at least two load measurement locations includes a first measurement location and a second measurement location each configured at a respective lateral side of said movable press member.

5. The method as recited in claim 1, wherein the at least two load measurement locations includes a first measurement location and a second measurement location each respectively configured at a forward side and a rearward side of said movable press member.

6. The method as recited in claim 1, wherein the at least two load measurement locations includes a pair of measurement locations spaced equidistantly from a reference axis.

7. The method as recited in claim 6, wherein the tipping moment determination step further comprises the steps of:

computing the difference between the respective load measurement signals associated with each respective one of said pair of measurement locations and generating a difference signal representative thereof; and

computing the tipping moment as a function of the generated difference signal and the displacement of either one of said pair of measurement locations relative to the reference axis.

8. The method as recited in claim 1, wherein the press machine monitoring activity occurs substantially continuously over at least the duration of the press machine slide travel.

9. The method as recited in claim 1, wherein the tipping moment evaluation step further includes the step of:

controlling the operation of the movable press member in accordance with the evaluation results.

10. A system for monitoring the operation of a press member machine having an operatively movable press member, comprising:

measurement means for providing a measure of the load developed within said movable press member at each respective one of at least two load measurement locations thereof and for generating load measurement signals representative thereof;

processor means, responsive to said load measurement signals generated by said measurement means, for determining a tipping movement experienced by said movable press member; and

evaluation means for evaluating the determined tipping movement relative to a predefined tipping movement severity level.

11. The system as recited in claim 10, wherein said measurement means further comprises:

a respective load sensor coupled to said movable press member at each respective one of said at least two load measurement locations.

12. The system as recited in claim 11, wherein said movable press member includes at least one of a press machine slide and a press machine stripper plate.

13. The system as recited in claim 10, wherein the at least two load measurement locations includes a first measurement location and a second measurement location each configured at a respective lateral side of said movable press member.

14. The system as recited in claim 10, wherein the at least two load measurement locations includes a first measurement location and a second measurement location each respectively configured at a forward side and a rearward side of said movable press member.

15. The system as recited in claim 10, wherein the at least two load measurement locations includes a pair of measurement locations spaced equidistantly from a reference axis.

16. The system as recited in claim 15, wherein said processor means further comprises:

first means for computing the difference between the respective load measurement signals associated with each respective one of said pair of measurement locations and generating a difference signal representative thereof; and

second means for computing the tipping moment as a function of the generated difference signal and the displacement of either one of said pair of measurement locations relative to the reference axis.

17. The system as recited in claim 10, wherein the press machine monitoring activity occurs substantially continuously over at least the duration of the press machine slide travel.

18. The system as recited in claim 10, wherein said evaluation means further comprises:

a controller to control the operation of said movable press member in accordance with the evaluation results.