EP0384374B1 - Coin selector - Google Patents

Coin selector Download PDF

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Publication number
EP0384374B1
EP0384374B1 EP90103193A EP90103193A EP0384374B1 EP 0384374 B1 EP0384374 B1 EP 0384374B1 EP 90103193 A EP90103193 A EP 90103193A EP 90103193 A EP90103193 A EP 90103193A EP 0384374 B1 EP0384374 B1 EP 0384374B1
Authority
EP
European Patent Office
Prior art keywords
frequency
converter
voltage
sensors
coin
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.)
Expired - Lifetime
Application number
EP90103193A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0384374A1 (en
Inventor
Massimo Mondardini
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.)
URMET SpA
Original Assignee
URMET SpA
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 URMET SpA filed Critical URMET SpA
Publication of EP0384374A1 publication Critical patent/EP0384374A1/en
Application granted granted Critical
Publication of EP0384374B1 publication Critical patent/EP0384374B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D5/00—Testing specially adapted to determine the identity or genuineness of coins, e.g. for segregating coins which are unacceptable or alien to a currency
    • G07D5/08—Testing the magnetic or electric properties
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D5/00—Testing specially adapted to determine the identity or genuineness of coins, e.g. for segregating coins which are unacceptable or alien to a currency
    • G07D5/02—Testing the dimensions, e.g. thickness, diameter; Testing the deformation

Definitions

  • the present invention relates to a coin selection device, and more precisely to a selection device of the frequency-deviation kind, in which the coins to be selected cross the alternating magnetic field of a plurality of probes or sensors arranged in succession along the path of said coins, each sensor including a high-frequency oscillator with at least one induction coil wound on a corresponding magnetic core which has polar expansions arranged facing the coin path, and in which the passage of the coin in front of the expansion of the core causes a frequency deviation which depends on the characteristic parameters of said coin and constitutes the measured datum on which the criterion for accepting or rejecting said coin is based.
  • the parameters suitable for the identification of a coin are constituted by its thickness, its diameter and by the nature of its material, and three sensors, respectively sensitive to said parameters and arranged in succession along the path of the coin, are used to detect them (US-A-4749074).
  • each sensor to the passage of the coins is represented, in terms of frequency and amplitude, by a bell-shaped curve with a maximum value located at a frequency "f” or respectively at an amplitude "V" which is characteristic of each series of coins, and the acceptance criterion is based on the fact that the coin being examined must be within a preset neighborhood of said maximum value defined by corresponding minimum and maximum threshold values such that fmi ⁇ f ⁇ fma or respectively Vmi ⁇ V ⁇ Vma, where fmi, fma and Vmi, Vma are the corresponding minimum and maximum threshold values expressed in terms of frequency or amplitude, respectively.
  • the geometric parameters of thickness and diameter are detected directly in terms of frequency, while a response in terms of amplitude is preferably detected for the nature of the material, in order to increase detection sensitivity; the datum thus detected is converted to a frequency by means of an A/F (amplitude/frequency) converter.
  • the operating frequency of the oscillators is variable for each sensor and is in the range of 1 MHz; the frequency signals are digitized and processed by successive logic circuits in order to actuate the selector.
  • the values of the minimum and maximum acceptance threshold are influenced by several parameters, and they mainly depend on the mechanical structure of the selector and on its operating temperature, which as is known considerably affects the behavior of electronic components with long- and middle-term thermal drifts.
  • the influence of the mechanical parameters on the spacing of the thresholds and therefore on the selectivity of the selector may be kept within narrow and constant limits by a corresponding uniformity in the quality of manufacture, on one hand, and by adjusting each selector after production by means of direct measurements performed with specimen coins, on the other hand.
  • the influence of the operating temperature as regards the widening of the acceptance range is decisive, to the detriment of selectivity, if the operating temperature can vary within substantial limits, for example comprised between -30 and +50°C, as typically occurs in selectors intended to be fitted to public telephones installed outdoors or in any case in non-conditioned locations.
  • a differential measurement between the frequency (or amplitude) at rest and the one determined by, and measured at, the passage of the coins has so far been used to reduce the effect of temperature on selectivity.
  • the minimum and maximum acceptance thresholds are therefore currently set at the response frequencies actually measured for the maximum and minimum limits of the operating temperature, and this entails a considerable widening of the acceptance range, with a consequent considerable reduction in the selectivity of the device for the intermediate temperature values comprised between the two extremes.
  • the essential aim of the present invention is to eliminate this severe disadvantage by providing an improved selector, of the kind comprising frequency-deviation sensors as specified, the selectivity whereof is substantially independent from the excursion of the operating temperature, in that said temperature does not affect the setting of the acceptance thresholds, so that said setting depends substantially or predominantly on the mechanical parameters alone of the selector, which can be optimized in any way, and on the unavoidable variations of the characteristic values within the range of each kind of coin for which the selector is preset.
  • Another important object of the present invention is to provide a selector as specified, wherein the substantial selectivity independence from the operating temperature is obtained with structurally simple means which do not require sophisticated and selected components and are therefore economical and practically free from maintenance and/or periodic checks and adjustments.
  • Another important object of the present invention is to provide a coin selector as specified, the selectivity whereof is also independent from the variations of the power supply voltage, and the power consumption whereof is comprised within very narrow limits, so as to be particularly suitable for use in the field of public telephones using sets enabled by tokens and/or coins.
  • the reference numeral 10 indicates the guiding channel for the coins M, which are inserted in an opening 11 of the channel which by virtue of known electromechanical routing means (not illustrated) feeds the coins to a cash-registering section or alternately to a return slot, depending on whether the coin is accepted or rejected by the selection device.
  • Said device substantially comprises an impact sensor S which, when struck by the coins, emits a signal for energizing the various circuits of the selector through a square wave shaper 101, and three sensors or probes A-B-C coupled to the guiding channel 10 and arranged in succession along the path of the coin with an appropriate mutual spacing which is in any case not lower than the diameter of the largest-size coin to be processed in the selector.
  • each of the sensors A and B comprises a pair of cylindrical magnetic cores ma-mb which are arranged mutually facing on the opposite walls of the channel and are provided with corresponding portions wa-wb of respective induction coils.
  • the sensor C normally comprises a single magnetic core mc, preferably in the shape of an ellipsoid, on which a corresponding induction coil wc is wound.
  • the coils wa-wb-wc are fed by respective oscillators 12, 13 and 14 tuned to frequencies "fo" which differ for each sensor but are all comprised between 0.5 and 1 MHz; the rest frequency "fo" of each oscillator is chosen according to known criteria in relation to the value measured by the respective sensor.
  • the response at the output of the various oscillators is represented, in terms of frequency and/or amplitude, by a bell-shaped curve the maximum value whereof is located at a frequency "f" which is in theory characteristic or typical for each parameter and for each series of coins.
  • the coin acceptance or rejection criterion is based on the fact that each tested coin is comprised within a preset neighborhood of the value of the typical frequency "f", for example a neighborhood comprised between +/-5% f, and this check is performed by a microprocessor ⁇ P which is a part of a logic processing, control and power supply circuit generally indicated by 20 in figure 1.
  • the microprocessor is programmed to analyze the useful signal of each sensor in order to find the absolute maximum value thereof and to compare said maximum value to corresponding minimum and maximum threshold values in order to give an acceptance or rejection response which correspondingly activates said mechanical routing means.
  • an amplitude/frequency converter 15 is interposed between the output of the oscillator 13 and the microprocessor; said converter comprises an RMS/DC transducer, indicated by 15a, which converts the effective value of the output signal of the oscillator into a corresponding direct voltage value, and a V/f converter, indicated by 15b, adapted to produce an AC signal the frequency whereof is proportional to the input direct voltage produced by the transducer 15a.
  • the circuit 20 comprises, besides the microprocessor ⁇ P, a memory MM, for example of the EPROM type, an OR-type circuit 21 for enabling and maintaining activation, a stabilized power supply source 23 and an electronic activation control switch 22 receiving an activation signal cc and a switch off signal cs and generating at least one reset signal cr for the impact sensor S.
  • the minimum and maximum threshold values to which the microprocessor compares the datum arriving from the respective sensors are not fixed but may vary depending on the operating temperature according to respective values which may be set in tables and stored in the memory MM of the circuit 20 or expressed by corresponding algorithms, according to preset mathematical functions, also stored in the form of computing routines.
  • a voltage source 17 is used, which is selectively insertable at the input of the converter 15 by means of a switch 16 which is activated by the control circuit 20.
  • the source 17, which is also temperature-stabilized, is adapted to produce a voltage V which, when converted into a frequency f′r by the converter 15, constitutes a reference datum from which a differential value, dependent on the operating temperature, can be obtained.
  • the reference frequency f'r is generated by the converter 15, which is powered by the source 17, at a given temperature, for example 25°C, in thermally stable conditions, and the datum f' (25°C) constitutes said reference value f'r which, after having been possibly acquired automatically, is stored in the memories MM of the circuit 20.
  • the microprocessor ⁇ P transitorily connects the output of the source 17 to the input of the converter 15 through the switch 16 upon each passage of a coin, before or after reading the signal of the material sensor 13.
  • a so-called operating frequency f't is thus generated by said converter 15; said frequency differs from the stored reference frequency f'r by an amount which depends on the influence of environmental temperature on the components of the circuit blocks which constitute the converter 15 considered as a whole.
  • the microprocessor ⁇ P computes the difference f't - f'r in order to obtain, upon each passage of a coin, a differential datum ⁇ ft which depends on the effect of the temperature.
  • care is to be taken to ensure that the thermal sensitivity of the circuit blocks of the converter 15 is greater than, or equal to, that of the remaining circuit components, so that the obtained differential datum ⁇ ft has a restrictive nature with respect to all the components of the device.
  • Said differential datum which can be substantially converted to a temperature measurement, is used by the microprocessor ⁇ P to determine, upon each readout of the sensors, triggered by the passage of a coin, corresponding correct maximum and minimum acceptance thresholds for the signals arriving from all of said sensors.
  • the correct threshold values for the readout of each sensor are advantageously stored in the form of corresponding tables TA-TB-TC (figure 2) in which a minimum and a maximum threshold, pre-calculated exclusively according to the mechanical parameters of the selector (the influence whereof is determined during adjustment) and of the statistical variance of the parameters of the coin for each kind of coin, correspond to each differential datum ⁇ ft.
  • the increment step of the differential data is chosen in relation to the intended selectivity, for example every 5°C, if the corresponding frequency variation of the converter 15 is significant for such a temperature variation.
  • Figure 2 illustrates in flowchart form the operating sequence of the microprocessor for setting the acceptance thresholds related to a generic measurement: - before or after the passage of a generic coin, the microprocessor receives a "start" command and consequently controls the switch 16 to connect the input of the converter 15 to the source 17.
  • the datum f't corresponding to the operating frequency is read.
  • the read datum f't is compared to the reference frequency f'r stored in the memory MM, the differential datum ⁇ ft is calculated, and the address for the tables TA-TB-TC, also stored in the ROM, is obtained.
  • the corresponding value of the respectively minimum and maximum correct thresholds H-K is read at the outputs Ua-Ub-Uc.
  • the microprocessor ⁇ P executes the routine for finding the maximum values of the signals arriving from the sensors A-B-C, for identifying the frequencies related to said maximum values and for comparing them with the acceptance range defined by said correct thresholds to emit an acceptance or rejection signal in the form of an identification code (for example six bits long) for the tested coin which correspondingly activates the electromechanical routing means associated with the channel 10.
  • an identification code for example six bits long

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Testing Of Coins (AREA)
EP90103193A 1989-02-23 1990-02-20 Coin selector Expired - Lifetime EP0384374B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT6712189 1989-02-23
IT8967121A IT1232018B (it) 1989-02-23 1989-02-23 Selezionatore di monete perfezionato

Publications (2)

Publication Number Publication Date
EP0384374A1 EP0384374A1 (en) 1990-08-29
EP0384374B1 true EP0384374B1 (en) 1993-10-20

Family

ID=11299765

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90103193A Expired - Lifetime EP0384374B1 (en) 1989-02-23 1990-02-20 Coin selector

Country Status (3)

Country Link
EP (1) EP0384374B1 (it)
DE (1) DE69003968D1 (it)
IT (1) IT1232018B (it)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69311812T2 (de) * 1992-10-14 1997-10-02 Tetrel Ltd Münzprüfer
JP3877118B2 (ja) * 1999-12-09 2007-02-07 株式会社日本コンラックス コイン検査方法および装置

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2547761A1 (de) * 1975-10-24 1977-04-28 Pruemm Geb Heuser Margot Elektronischer muenzpruefer
US4460003A (en) * 1981-08-21 1984-07-17 Mars, Inc. Coin presence sensing apparatus
DE3486213T2 (de) * 1983-11-04 1994-01-13 Mars Inc Münzprüfer.
US4749074A (en) * 1985-10-11 1988-06-07 Matsushita Electric Industrial Co., Ltd. Coin sorting apparatus with reference value correction system

Also Published As

Publication number Publication date
DE69003968D1 (de) 1993-11-25
IT8967121A0 (it) 1989-02-23
EP0384374A1 (en) 1990-08-29
IT1232018B (it) 1992-01-23

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