GB2127973A - Monitoring a power press electrically - Google Patents

Monitoring a power press electrically Download PDF

Info

Publication number
GB2127973A
GB2127973A GB08228459A GB8228459A GB2127973A GB 2127973 A GB2127973 A GB 2127973A GB 08228459 A GB08228459 A GB 08228459A GB 8228459 A GB8228459 A GB 8228459A GB 2127973 A GB2127973 A GB 2127973A
Authority
GB
United Kingdom
Prior art keywords
press
signal
strain
monitoring
during
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08228459A
Other versions
GB2127973B (en
Inventor
Alec Thomas Harris
Derek James Pasquire
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BL Technology Ltd
Original Assignee
BL Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BL Technology Ltd filed Critical BL Technology Ltd
Priority to GB08228459A priority Critical patent/GB2127973B/en
Publication of GB2127973A publication Critical patent/GB2127973A/en
Application granted granted Critical
Publication of GB2127973B publication Critical patent/GB2127973B/en
Expired legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/0094—Press load monitoring means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/28—Arrangements for preventing distortion of, or damage to, presses or parts thereof
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/0061—Force sensors associated with industrial machines or actuators
    • G01L5/0071—Specific indicating arrangements, e.g. of overload
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/0061—Force sensors associated with industrial machines or actuators
    • G01L5/0076—Force sensors associated with manufacturing machines

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Presses And Accessory Devices Thereof (AREA)
  • Control Of Presses (AREA)

Abstract

The operation of a power press is monitored during operation by means of a strain gauge fitted to a part of the press subject to strain during operation, the output of the strain gauge being digitised. The digitised signal for each press cycle is then compared with a standard signal, and comparison of the two makes it possible to detect malfunction of the dies or other faults.

Description

SPECIFICATION Monitoring a power press This invention relates to a method of monitoring the operation of a power press during operation, and includes both means for monitoring power presses and power presses that include such means.
According to the invention a method of monitoring the operation of a power press during operation includes:a) fitting a strain responsive signal generating device to a member ofthe press that is subject to strain during operation ofthe press; b) digitising the signal generated by the device and calibrating the signal such that it represents the press loads during operation; c) storing the digitised signal for each press cycle; d) comparing the stored signal with a standard signal; e) generating a further signal to represent differ.
ences found between the stored signal and the standard signal.
Typically the further signal will be displayed to enable malfunction or faults to be rectified. The invention provides an accurate means for monitoring press loads during setting up and during press operation which can be utilised not only to reduce the peak press loadsto a value necessary to produce a satisfactory product but also to detect any malfunction of the dies, two blanks being pressed or any other fault that causes variations in the press load to occur. In effectthe "profiles" of actual press load and "ideal" press load are continuously monitored and discrepances between them can be evaluated to optimise press setting up and operation. it has been found that manyfeatures ofthe profile can be identified as specific operating events during the press cycle.
In the practice several strain responsive signal generating devices may be employed on each press and each strain responsive signal generating device may comprise a strain gauge bridge network; and the devices may be attached to convenient parts on the press structure such as the frame and press connecting rods.
The signal from the strain responsive device may be calibrated using a load cell orfrom known press data.
The invention will now be described by of example with reference to the accompanying drawings in which; Figure lisa block diagram of a press monitoring arrangement according to the invention; and Figure 2 is an example of a typical trace obtained during press operation.
Referring to Figure 1, strain gauge bridge networks 11 are fitted to members of a press that are subjectto strain during operation such as the connecting rods and/or to other parts of a power press (not shown), and the signals derived therefrom are fed to a pre-set gain sensing amplifier 12 which has the gain set by reference to a load cell or known press data such that the amplifier output represents the actual instantaneous press load.
The output of the amplifier is fed to a suitable recorder 13 and digitised by a AID convertor circuit 14 whose output is fed to the monitoring microprocessor 15. Atiming control logic circuit 20 triggered by either a pre-determined strain level fed from a press stroke detector 19, or by a suitable signal derived from switching device (not shown) activated by rotation of the press atthe appropriatetime during the press cycle, initiates sequential monitoring operation bythe microprocessor circuit 15. The digital output signal of the A/D circuit 14 is fed to a microprocessor monitoring system 15which can store known strain profile data and compare such data with real time monitored data.Comparison of data providing meansformes- sage generation on VDU/printer, ie split panel, overload contition etc. A communication link is also procided from the monitoring system microprocessor to a central monitoring computer or PC.
The amplifier 12 is provided with a closed loop stabilizer feedback circuit consisting of an integrator 17 and error detection circuit 18forautomatically zeroing the output of the amplifierwith the press under no strain. During press operation with the press stroke detector 19 detecting press strain above the predetermined strain level the integrator circuit 17 is suppressed by a signal from the detector to prevent self compensation action of the stabilizer circuittaking place.
Figure 2 illustrates a typical trace of press load plotted against time during a single operation of the press. The peak load is indicated by the letter'A', and it has been found that such a trace is consistently produced during normal operation. However,the other peaks (typically B, C) and troughs also represent significant events which may indicate a problem developing which can be dealt with before press operation is adversely affected.
Thusthe digital/analogue values ofthe strain signal when fed to a visual display unit 13, orto a recording/monitoring system 15 allows, a) the press to be set up efficiently without excessive loads being produced, b) a true stamping count to be made without free runs, which produce a reduced peak load, being recorded, c) a safety cut out to be actuated if the load becomes excessive during operation, and d) press/die malfunction/fault information to be presented on VDU/printer 16 in English text.
CLAIMS (Filed on 11 Nov82) 1. A method of monitoring the operation of a power press during operation which includes:a) fitting a strain responsive signal generating device to a member ofthe press that is subject to strain during operation of the press; b) digitisingthesignal generated bythe device and calibrating the signal such that it represents the press The drawing(s) originally filed were informal and the print here reproduced is taken from a later filed formal copy.
This print takes account of replacement documents later filed to enable the application to comply with the formal requirements of the Patents Rules 1982.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Monitoring a power press This invention relates to a method of monitoring the operation of a power press during operation, and includes both means for monitoring power presses and power presses that include such means. According to the invention a method of monitoring the operation of a power press during operation includes:a) fitting a strain responsive signal generating device to a member ofthe press that is subject to strain during operation ofthe press; b) digitising the signal generated by the device and calibrating the signal such that it represents the press loads during operation; c) storing the digitised signal for each press cycle; d) comparing the stored signal with a standard signal; e) generating a further signal to represent differ. ences found between the stored signal and the standard signal. Typically the further signal will be displayed to enable malfunction or faults to be rectified. The invention provides an accurate means for monitoring press loads during setting up and during press operation which can be utilised not only to reduce the peak press loadsto a value necessary to produce a satisfactory product but also to detect any malfunction of the dies, two blanks being pressed or any other fault that causes variations in the press load to occur. In effectthe "profiles" of actual press load and "ideal" press load are continuously monitored and discrepances between them can be evaluated to optimise press setting up and operation. it has been found that manyfeatures ofthe profile can be identified as specific operating events during the press cycle. In the practice several strain responsive signal generating devices may be employed on each press and each strain responsive signal generating device may comprise a strain gauge bridge network; and the devices may be attached to convenient parts on the press structure such as the frame and press connecting rods. The signal from the strain responsive device may be calibrated using a load cell orfrom known press data. The invention will now be described by of example with reference to the accompanying drawings in which; Figure lisa block diagram of a press monitoring arrangement according to the invention; and Figure 2 is an example of a typical trace obtained during press operation. Referring to Figure 1, strain gauge bridge networks 11 are fitted to members of a press that are subjectto strain during operation such as the connecting rods and/or to other parts of a power press (not shown), and the signals derived therefrom are fed to a pre-set gain sensing amplifier 12 which has the gain set by reference to a load cell or known press data such that the amplifier output represents the actual instantaneous press load. The output of the amplifier is fed to a suitable recorder 13 and digitised by a AID convertor circuit 14 whose output is fed to the monitoring microprocessor 15. Atiming control logic circuit 20 triggered by either a pre-determined strain level fed from a press stroke detector 19, or by a suitable signal derived from switching device (not shown) activated by rotation of the press atthe appropriatetime during the press cycle, initiates sequential monitoring operation bythe microprocessor circuit 15. The digital output signal of the A/D circuit 14 is fed to a microprocessor monitoring system 15which can store known strain profile data and compare such data with real time monitored data.Comparison of data providing meansformes- sage generation on VDU/printer, ie split panel, overload contition etc. A communication link is also procided from the monitoring system microprocessor to a central monitoring computer or PC. The amplifier 12 is provided with a closed loop stabilizer feedback circuit consisting of an integrator 17 and error detection circuit 18forautomatically zeroing the output of the amplifierwith the press under no strain. During press operation with the press stroke detector 19 detecting press strain above the predetermined strain level the integrator circuit 17 is suppressed by a signal from the detector to prevent self compensation action of the stabilizer circuittaking place. Figure 2 illustrates a typical trace of press load plotted against time during a single operation of the press. The peak load is indicated by the letter'A', and it has been found that such a trace is consistently produced during normal operation. However,the other peaks (typically B, C) and troughs also represent significant events which may indicate a problem developing which can be dealt with before press operation is adversely affected. Thusthe digital/analogue values ofthe strain signal when fed to a visual display unit 13, orto a recording/monitoring system 15 allows, a) the press to be set up efficiently without excessive loads being produced, b) a true stamping count to be made without free runs, which produce a reduced peak load, being recorded, c) a safety cut out to be actuated if the load becomes excessive during operation, and d) press/die malfunction/fault information to be presented on VDU/printer 16 in English text. CLAIMS (Filed on 11 Nov82)
1. A method of monitoring the operation of a power press during operation which includes:a) fitting a strain responsive signal generating device to a member ofthe press that is subject to strain during operation of the press; b) digitisingthesignal generated bythe device and calibrating the signal such that it represents the press The drawing(s) originally filed were informal and the print here reproduced is taken from a later filed formal copy.
This print takes account of replacement documents later filed to enable the application to comply with the formal requirements of the Patents Rules 1982.
loads during operation; c) storing the digitised signal for each press cycle; d) comparing the stored signal with a standard signal; e) generating a further signal to represent differencesfound between the stored signal and the standard signal.
2. A method as claimed in claim 1, wherein the strain responsive signal generating device comprises a strain guage bridge network.
3. A method as claimed in claim 1 or claim 2, wherein the strain responsive signal generating device is calibrated using a load cell or from known press data.
4. A method of monitoring the operation of a power press during operation substantially as herein before described with reference to the accompanying drawings.
GB08228459A 1982-10-05 1982-10-05 Monitoring a power press electrically Expired GB2127973B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08228459A GB2127973B (en) 1982-10-05 1982-10-05 Monitoring a power press electrically

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08228459A GB2127973B (en) 1982-10-05 1982-10-05 Monitoring a power press electrically

Publications (2)

Publication Number Publication Date
GB2127973A true GB2127973A (en) 1984-04-18
GB2127973B GB2127973B (en) 1986-02-12

Family

ID=10533402

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08228459A Expired GB2127973B (en) 1982-10-05 1982-10-05 Monitoring a power press electrically

Country Status (1)

Country Link
GB (1) GB2127973B (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0181234A2 (en) * 1984-11-09 1986-05-14 Continental Can Company, Inc. Applied force monitor for apparatus for forming products from sheet material
EP0358405A2 (en) * 1988-09-08 1990-03-14 Trw Steering Systems Japan Co., Ltd. Apparatus and method of detecting abnormal load of pressurizing apparatus
EP0417485A2 (en) * 1989-09-12 1991-03-20 Dorst Maschinen und Anlagenbau Otto Dorst und Dipl.-Ing Walter Schlegel GmbH & Co. Press for making dimensionally stable pressed articles from particulate material
EP0596697A1 (en) * 1992-11-05 1994-05-11 Toyota Jidosha Kabushiki Kaisha Device and method for measuring and adjusting pressing load values on a press
EP0612992A2 (en) * 1993-02-25 1994-08-31 Toyota Jidosha Kabushiki Kaisha Method of diagnosing pressing machine based on detected physical value as compared with reference
US5450756A (en) * 1992-11-06 1995-09-19 Toyota Jidosha Kabushiki Kaisha Device and method for measuring and adjusting pressing load values on a press
EP1701146A1 (en) * 2005-03-09 2006-09-13 Riken Optech Corporation Zero point correction circuit of load meter

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2007845A (en) * 1977-09-22 1979-05-23 Fette Wilhelm Gmbh Method of producing data concerning the production of tablets, and a tablet-making press
GB2064134A (en) * 1979-11-24 1981-06-10 British Leyland Cars Ltd Monitoring press forces electrically

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2007845A (en) * 1977-09-22 1979-05-23 Fette Wilhelm Gmbh Method of producing data concerning the production of tablets, and a tablet-making press
GB2064134A (en) * 1979-11-24 1981-06-10 British Leyland Cars Ltd Monitoring press forces electrically

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0181234A2 (en) * 1984-11-09 1986-05-14 Continental Can Company, Inc. Applied force monitor for apparatus for forming products from sheet material
EP0181234A3 (en) * 1984-11-09 1989-02-22 Continental Can Company, Inc. Applied force monitor for apparatus for forming products from sheet material
EP0358405A2 (en) * 1988-09-08 1990-03-14 Trw Steering Systems Japan Co., Ltd. Apparatus and method of detecting abnormal load of pressurizing apparatus
US4979401A (en) * 1988-09-08 1990-12-25 Trw Steering & Industrial Products (Japan) Co., Ltd. Apparatus and method of detecting abnormal load of pressurizing apparatus
EP0358405A3 (en) * 1988-09-08 1991-07-03 Trw Steering Systems Japan Co., Ltd. Apparatus and method of detecting abnormal load of pressurizing apparatus
AU621146B2 (en) * 1988-09-08 1992-03-05 Trw Steering & Industrial Products (Japan) Co., Ltd. Apparatus and method of detecting abnormal load of pressurizing apparatus
EP0417485A2 (en) * 1989-09-12 1991-03-20 Dorst Maschinen und Anlagenbau Otto Dorst und Dipl.-Ing Walter Schlegel GmbH & Co. Press for making dimensionally stable pressed articles from particulate material
EP0417485A3 (en) * 1989-09-12 1991-07-17 Dorst Maschinen Und Anlagenbau Otto Dorst Und Dipl.-Ing Walter Schlegel Gmbh & Co. Press for making dimensionally stable pressed articles from particulate material
EP0596697A1 (en) * 1992-11-05 1994-05-11 Toyota Jidosha Kabushiki Kaisha Device and method for measuring and adjusting pressing load values on a press
US5450756A (en) * 1992-11-06 1995-09-19 Toyota Jidosha Kabushiki Kaisha Device and method for measuring and adjusting pressing load values on a press
EP0612992A2 (en) * 1993-02-25 1994-08-31 Toyota Jidosha Kabushiki Kaisha Method of diagnosing pressing machine based on detected physical value as compared with reference
EP0612992A3 (en) * 1993-02-25 1995-04-05 Toyota Motor Co Ltd Method of diagnosing pressing machine based on detected physical value as compared with reference.
EP0733435A2 (en) * 1993-02-25 1996-09-25 Toyota Jidosha Kabushiki Kaisha Method of diagnosing pressing machine based on detected physical value as compared with reference
EP0733435A3 (en) * 1993-02-25 1997-09-24 Toyota Motor Co Ltd Method of diagnosing pressing machine based on detected physical value as compared with reference
US5692404A (en) * 1993-02-25 1997-12-02 Toyota Jidosha Kabushiki Kaisha Method of diagnosing pressing machine based on detected physical value as compared with reference
EP1701146A1 (en) * 2005-03-09 2006-09-13 Riken Optech Corporation Zero point correction circuit of load meter

Also Published As

Publication number Publication date
GB2127973B (en) 1986-02-12

Similar Documents

Publication Publication Date Title
US5745376A (en) Method of detecting excessive keyboard force
US3930248A (en) Impact sensing detector
US4030868A (en) Force measurement and analysis particularly relating to rotary tablet presses
US4274282A (en) Sensor for reciprocating press
IE38529L (en) Monitoring a system
GB2127973A (en) Monitoring a power press electrically
WO1982004010A1 (en) A method and apparatus for monitoring a press
JPS569099A (en) Abnormality detecting method of automatic press
GB1173235A (en) Load Indicating Devices for Compacting Press
EP0041578A1 (en) Device for monitoring abnormality in sampled signals
US3999424A (en) Strain-gauge pressure detector for penetrometer
CN116953413B (en) Fault diagnosis system based on components and parts in cubical switchboard
GB2064134A (en) Monitoring press forces electrically
EP0358405A3 (en) Apparatus and method of detecting abnormal load of pressurizing apparatus
KR910006811A (en) Multiple Input Signal Checking Circuit
US6927711B2 (en) Sensor apparatus
CN206632744U (en) A kind of machine safety operates alarming device
JPH05189679A (en) Alarm suppressing information forming system and alarm processing system
JP3048392B2 (en) Satellite monitoring device
JPS59164987A (en) Reactivity monitoring device of fast reactor
JPS5844998A (en) Detecting device for maximum load generating angle of press machine
SU845023A2 (en) Press force meter
JPS5644907A (en) Anomaly monitor device
JPS59193337A (en) Detection of abnormal in blank material
JPS5825899A (en) Method and device for detecting abnormal operation of reciprocating body

Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19931005