EP0170484A2 - Anzeiger für die abgelaufene Zeit - Google Patents

Anzeiger für die abgelaufene Zeit Download PDF

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Publication number
EP0170484A2
EP0170484A2 EP85305231A EP85305231A EP0170484A2 EP 0170484 A2 EP0170484 A2 EP 0170484A2 EP 85305231 A EP85305231 A EP 85305231A EP 85305231 A EP85305231 A EP 85305231A EP 0170484 A2 EP0170484 A2 EP 0170484A2
Authority
EP
European Patent Office
Prior art keywords
potential difference
state
indicator element
cell
circuit
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.)
Withdrawn
Application number
EP85305231A
Other languages
English (en)
French (fr)
Other versions
EP0170484A3 (de
Inventor
Robin Andras Benedek
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.)
Johnson Matthey PLC
Original Assignee
Johnson Matthey PLC
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 Johnson Matthey PLC filed Critical Johnson Matthey PLC
Publication of EP0170484A2 publication Critical patent/EP0170484A2/de
Publication of EP0170484A3 publication Critical patent/EP0170484A3/de
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G04—HOROLOGY
    • G04F—TIME-INTERVAL MEASURING
    • G04F1/00—Apparatus which can be set and started to measure-off predetermined or adjustably-fixed time intervals without driving mechanisms, e.g. egg timers
    • G04F1/005—Apparatus which can be set and started to measure-off predetermined or adjustably-fixed time intervals without driving mechanisms, e.g. egg timers using electronic timing, e.g. counting means

Definitions

  • This invention relates to electrically operated apparatus for indicating the lapse of a pre-determined time period.
  • This may be a continuous, uninterrupted period or it may be the aggregate of a series of discontinuous time periods of equal or unequal length.
  • Apparatus according to the invention may be used for indicating the end or the approach of the end of the shelf life of material, such as gold bonding wire, which deteriorates within a relatively short period of its manufacture. It may also be used for indicating when, for example, electronic equipment which is required to be periodically aligned or adjusted is due for such attention. Apparatus according to the invention is, however, especially well adapted for use in connection with the maintenance of equipment in the quality assurance field.
  • the invention provides an electrically operated apparatus for indicating the lapse of a predetermined time period the apparatus comprising an indicator element which is changeable from a first state to a second state when an electrical potential difference greater than a specified value is applied thereto and is automatically revertable to the first state when the electrical potential difference applied to the element is equal to or less that the specified value, in combination with a circuit with means for controlling as a function of time a potential difference, applied to the indicator element.
  • a potential difference is applied to the indicator element such that at the beginning of the time period the potential difference is greater than the specified value so that the indicator element changes from the first state to the second state and at the end of the time period the potential difference is less than or equal to the specified value and the element reverts to the first state to indicate the lapse of the period.
  • the present invention provides a method for indicating the lapse of a predetermined time period comprising applying a potential difference to an indicator element which is changeable from a first state to a second state when an electrical potential difference greater than a specified value is applied thereto and is automatically revertable to the first state when the electrical potential difference applied to the element is equal to or less that the specified value, the potential difference being controlled as a function of time.
  • the applied potential difference is provided R 88 by a source of electric current of known capacity by which any be / meant a source of electric current that will supply a known current at a substantially constant potential difference for a known time period, at the end of which period or fairly shortly thereafter the source is discharged or effectively discharged.
  • the source is effectively discharged when its potential difference has been reduced to a value equal to or lower than the specified value as defined above of potential difference referred to in the immediately preceding definition.
  • the source of electric current of known current may be any suitable type of electric cell or battery such as one or more silver oxide cells. These cells have a relatively constant voltage during discharge and this voltage falls rapidly when the completely discharged condition is closely approached.
  • An indicator element is a device having a high electrical resistance, usually not less than 500 kilohm, which changes from a first to a second state when there is applied to it, via, for example, suitable terminals, an electrical potential difference greater than a specified value and which reverts automatically to the said first state upon the reduction of the applied potential difference to a value equal to or less than the specified value.
  • the indicator element may be any suitable electrically operated device.
  • Particularly suitable is an optical shutter comprising or consisting of an electrochromic device or a sheet of liquid crystal material.
  • the material is associated with an oscillator or has an oscillator secured to or embedded in it.
  • the optical shutter is transparent and in the other opaque.
  • the applied potential difference is controlled as a function of time by the circuit, in which a current flows, with a means for controlling the magnitude of the current.
  • the means for controlling the magnitude of the current in the circuit may be a bleed resistor connected in parallel with the indicator device, or a current controlling circuit suitably incorporated in the circuit of the apparatus according to the invention.
  • means are provided for reducing the current to a very low if not insignificant value at the end of each time period and then re-establishing it at or effectively at its previous value at the beginning of the next succeeding time period without, in either case, the potential difference applied to the indicator element being materially affected.
  • a bleed resistor When a bleed resistor is provided in parallel with the indicator device as a means for controlling the magnitude of the current in the circuit, this resistor may simply be disconnected at the end of each time period and reconnected at the beginning of the next succeeding time period.
  • Apparatus according to this invention may also include a sensor and an associated latch circuit.
  • This apparatus will indicate either that a predetermined time period has elapsed or that certain physical conditions have changed to above or below a preset limit so that for example the apparatus will indicate that equipment which has been moved requires recalibration before the predetermined time period has elapsed.
  • Weighing scales used in shops and in trade should be recalibrated after a certain time period or after the weighing scales have been moved.
  • Apparatus which includes a sensor that detects movement can be fixed onto a weighing scales so that the indicator element will show that the weighing scales need recalibration either after the predetemined time period has elapsed or the scales have been moved.
  • the sensor is used to measure or detect a physical condition such as movement, acceleration, temperature, pressure, humidity, electro-magnetic radiation, magnetic field, electric field, alpha particles, beta particles, fluid flow or level or the presence of a certain gas or fluid.
  • a physical condition such as movement, acceleration, temperature, pressure, humidity, electro-magnetic radiation, magnetic field, electric field, alpha particles, beta particles, fluid flow or level or the presence of a certain gas or fluid.
  • the sensor may be a mercury tilt switch which is normally either on or off.
  • the latch circuit may be a means of shorting the terminals of the source of electric current in its simplest form.
  • An apparatus as described as above may be used to indicate the end of the shelf life of a material which deteriorates after a certain period of time. The material may also deteriorate if it is subjected to for example high humidity or high temperature.
  • An apparatus comprising a source of electric current connected by a circuit, which has a means to control the potential difference (a resistor), to an indicator element with a sensor and associated latch circuit can be used to indicate that a material has reached the end of its shelf life. If the sensor is a temperature measuring sensor the apparatus can also indicate that the material should be disposed of if it has been subjected to a temperature above a set limit.
  • Some chemical products and pharmaceutical products are examples of materials which have a certain shelf life as long as they are kept in certain conditions, eg in a refrigerator, but which deteriorate rapidly if the temperature rises.
  • a silver oxide cell 1 is connected via a switch 2 to the input terminals 3 of a high input impedance, 30-100 Hz oscillator 4, the output terminals 5 of which are connected to the input terminals 6 of a sheet 7 of liquid crystal material which acts as an optical shutter.
  • the input resistance of this optical shutter is at least 500 kilohms.
  • a series-connected resistor 9 and switch 10 In parallel with the input terminals 3 of oscillator 4 are a series-connected resistor 9 and switch 10.
  • a piece of card 8 or other suitable material bearing the legend "RE-CALIBRATE", preferably in fluorescent ink.
  • the apparatus is intended to indicate the lapse of a predetermined time period and hence that equipment, such as a thermocouple, for example, is due for re-calibration.
  • switches 2 and 10 are closed when the equipment is brought into service, whereupon the cell 1 begins to discharge via the resistor 9 which acts as a bleed resistor. It is in part discharged through the input circuit of oscillator 4 but here the current drain is by comparison negligibly small.
  • Oscillator 4 when energised in this way applies a low frequency (30-100 Hz) oscillating (alternating) voltage to the optical shutter 7 from its output terminals 5.
  • the liquid crystal material of this optical shutter has a 'first state' in which it is transparent and a 'second state' in which it is opaque (or essentially so). Upon the closure of switch 2 (assuming cell 1 is not discharged) the liquid crystal material is converted to its second state and becomes opaque, thus making it impossible to read the legend RE-CALIBRATE.
  • switch 10 Upon the closure of switch 10 (switch 2 also being closed) the cell 1 discharges through the bleed resistor 9 and becomes discharged or effectively discharged after a period which depends upon the value of resistor 9, the type of cell employed and to a lesser extent the ambient temperature.
  • Cell 1 and resistor 9 are so chosen that the period from 'switch-on', corresponding to the bringing into service of the equipment, to the time when the cell is discharged or effectively discharged, at which point the liquid crystal material of optical shutter 7 reverts to its first (transparent) state and the legend RE-CALIBRATE is visible through the material, corresponds to the "calibration period" of the equipment, upon the expiry of which period the equipment needs to be re-calibrated. The length of this period will depend upon the nature of the equipment and the use to which it is put. It is assumed here that the equipment is either used continuously or is subject to a known and predictable regime of use.
  • the cell 1 should have a rapid fall-off in voltage as it approaches exhaustion (that is, until it is discharged or effectively discharged) and should preferably have a relatively constant voltage during discharge prior to this.
  • a discharge characteristic of such a cell is shown in fig. 2.
  • a suitable cell is a DURACELL (Registered Trade Mark) cell, type D350, which has a nominal voltage of 1.5 volts and a nominal capacity of 100 mAh. Its voltage stays substantially constant until very near the end of its life when it falls rapidly to zero as indicated in fig. 2. If it is required that the apparatus of figure 1 should indicate the lapse of, say, 1000 hours, the resistor R would need to have a value of kilohms. The period of 1000 hours is, for example, a typical figure for the life of a platinum/platinum-rhodium thermocouple before re-calibration is required, when the thermocouple is used continuously at 1000°C.
  • DURACELL Registered Trade Mark
  • switch 10 should be closed at the beginning of each period of use and opened at the end of it, this process being repeated until the cell 1 is discharged or effectively discharged, whereupon the word RE-CALIBRATE becomes visible through the optical shutter.
  • switch 10 may, of course, be omitted.
  • switch 2 may also be omitted so as to prevent the accidental switching off of the cell or battery during use. In this case, the cell or battery would simply be connected into the circuit upon the bringing into service of the equipment with which the apparatus of fig. 1 is to be used.
  • the first embodiment of the apparatus is also shown as a schematic diagram in figure 3.
  • the device comprises a cell 11 which is connected to input terminals of an oscillator gate 13.
  • the output terminals of the oscillator gate 13 are connected to input terminals of an optical shutter 14.
  • a resistor 12 is connected in parallel with the oscillator.
  • the device comprises a cell 11, a resistor 12, an oscillator 13, an optical shutter 14, a sensor 15 and a latch circuit 16.
  • the sensor 15 is connected in parallel with the resistor 12 with an output to an input terminal of the oscillator gate 13 via a latch circuit 16.
  • Suitable sensors have two states, on or off, for example a mercury tilt switch. Such a sensor will normally be in the off position until the physical condition which it is measuring, eg movement, causes it to switch to the on postion. Latch circuit 16 will then come into effect and the potential difference supplied to optical shutter 14 will decrease causing optical shutter 14 to revert to its first state.
  • the device is similar to the second embodiment and enables sensors with a continuous output to be used.
  • a comparator 17 is connected between the sensor and the latch circuit. Comparator 17 enables the output from sensor 15 to be compared with a preset value such that when the physical condition being measured by sensor 15 results in the output from sensor 15 reaching the preset value latch circuit 16 will come into effect.
  • Sensor 15 may measure temperature, pressure, humidity, electro-magnetic radiation, magnetic fields, electric fields, alpha particles, beta particles, fluid flow or level or it may detect the presence of a particular fluid or compound.
  • a circuit diagram for the second embodiment of the invention is shown in figure 6.
  • a cell 21 is connected to an oscillator gate 23A, 23B, 23C, 23D, 23E, 23F which is connected to an optical shutter 24.
  • a resistor 22 is connected across the terminals of cell 21.
  • a sensor 25A is connected in parallel with resistor 22.
  • a latch circuit comprises 26A, 26B, 26C and 26D. The values of resistors 25B and 26D are chosen so that the power consumption of latch circuit 26A, 26B, 26C and 26D and sensor 25A is minimal.
  • Gates 26A and 26B are NOR gates, 1/4 of a quad 2-input device type 4001B.
  • Gates 23A, 23B and 23C are exclusive OR gates, 1/4 of a quad 2-input device type 4070B.
  • a type of optical shutter could for example be used which would be 'open' (transparent) when the equipment is in use and would only close when the cell is discharged or effectively discharged.
  • the legend visible when the shutter is open could be IN SERVICE, or SERVICEABLE or something similar.
  • apparatus according to the invention can be used in many fields other than the indication of the expiry of the "calibration period" of equipment.
  • the legend displayed could be, for example, RE-ALIGN, SHELF-LIFE ENDED, REPLACE and so on.
  • the indicator element may be one which is not an optical shutter but which has two messages imprinted on it. One message would be visible in the absence of an applied potential difference whilst the other message would become visible upon the application of a potential difference (a.c. or d.c.). The second message could add to or replace the first message.
  • apparatus according to the invention is particularly useful in the quality assurance field and where any equipment requires periodic attention. It would also be of considerable value in connection with equipment for the armed forces which requires periodic checking and in connection with precision laboratory equipment.
  • a particular advantage of apparatus according to the invention is that it is fail safe in that failure of the cell or the battery will have the same effect as its being discharged or effectively discharged at the end of the period being measured. In other words, if the cell or battery fails, the apparatus will (prematurely) read RE-CALIBRATE or RE-ALIGN and so on.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electric Clocks (AREA)
  • Measurement Of Unknown Time Intervals (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
EP85305231A 1984-08-01 1985-07-23 Anzeiger für die abgelaufene Zeit Withdrawn EP0170484A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8419578 1984-08-01
GB848419578A GB8419578D0 (en) 1984-08-01 1984-08-01 Elapsed time indicator

Publications (2)

Publication Number Publication Date
EP0170484A2 true EP0170484A2 (de) 1986-02-05
EP0170484A3 EP0170484A3 (de) 1986-04-02

Family

ID=10564761

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85305231A Withdrawn EP0170484A3 (de) 1984-08-01 1985-07-23 Anzeiger für die abgelaufene Zeit

Country Status (4)

Country Link
EP (1) EP0170484A3 (de)
JP (1) JPS62247284A (de)
ES (1) ES8707806A1 (de)
GB (1) GB8419578D0 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0326385A1 (de) * 1988-01-28 1989-08-02 Colin Electronics Co., Ltd. Gerät zur Feststellung von Impulswellen
WO1990006564A1 (en) * 1988-11-30 1990-06-14 John Bentley Electric key apparatus
FR2652660A1 (fr) * 1989-07-17 1991-04-05 Guessous Ahmed Karim Vignette d'assurance electronique.
WO1991006838A2 (de) * 1989-11-02 1991-05-16 Badische Tabakmanufaktur Roth-Händle Gmbh Elektrischer verfallsindikator

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2337927A1 (de) * 1973-07-26 1975-02-13 Heuer Sen Vorrichtung zur anzeige des erlaubten oder nichterlaubten parkens von kraftfahrzeugen
JPS5342777A (en) * 1976-09-29 1978-04-18 Seiko Instr & Electronics Ltd Electronic watch
DE2739819A1 (de) * 1977-09-03 1979-06-13 Kieninger & Obergfell Spannungsueberwachungsvorrichtung, vorzugsweise zur ueberwachung der stromquelle einer elektrischen uhr
DE3313087A1 (de) * 1982-04-24 1983-11-03 Satchwell Birka Regelungstechnik Gmbh, 5630 Remscheid Elektronisches zeitwerk
EP0135930A2 (de) * 1983-09-27 1985-04-03 Omron Tateisi Electronics Co. Spannungsversorgung für Zeitverzögerungsschaltung mit Flüssigkristallanzeige

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2337927A1 (de) * 1973-07-26 1975-02-13 Heuer Sen Vorrichtung zur anzeige des erlaubten oder nichterlaubten parkens von kraftfahrzeugen
JPS5342777A (en) * 1976-09-29 1978-04-18 Seiko Instr & Electronics Ltd Electronic watch
DE2739819A1 (de) * 1977-09-03 1979-06-13 Kieninger & Obergfell Spannungsueberwachungsvorrichtung, vorzugsweise zur ueberwachung der stromquelle einer elektrischen uhr
DE3313087A1 (de) * 1982-04-24 1983-11-03 Satchwell Birka Regelungstechnik Gmbh, 5630 Remscheid Elektronisches zeitwerk
EP0135930A2 (de) * 1983-09-27 1985-04-03 Omron Tateisi Electronics Co. Spannungsversorgung für Zeitverzögerungsschaltung mit Flüssigkristallanzeige

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENTS ABSTRACTS OF JAPAN, vol. 2, no. 77, 17th June 1978, page 3176 E 78; & JP - A - 53 42 777 (DAINI SEIKOSHA K.K.) 18-04-1978 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0326385A1 (de) * 1988-01-28 1989-08-02 Colin Electronics Co., Ltd. Gerät zur Feststellung von Impulswellen
US4928700A (en) * 1988-01-28 1990-05-29 Colin Electronics Co., Ltd. Pulse wave detecting apparatus
WO1990006564A1 (en) * 1988-11-30 1990-06-14 John Bentley Electric key apparatus
FR2652660A1 (fr) * 1989-07-17 1991-04-05 Guessous Ahmed Karim Vignette d'assurance electronique.
WO1991006838A2 (de) * 1989-11-02 1991-05-16 Badische Tabakmanufaktur Roth-Händle Gmbh Elektrischer verfallsindikator
WO1991006838A3 (de) * 1989-11-02 1991-07-25 Badische Tabakmanufaktur Elektrischer verfallsindikator

Also Published As

Publication number Publication date
ES8707806A1 (es) 1987-08-16
JPS62247284A (ja) 1987-10-28
EP0170484A3 (de) 1986-04-02
ES545809A0 (es) 1987-08-16
GB8419578D0 (en) 1984-09-05

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Inventor name: BENEDEK, ROBIN ANDRAS