Abstract: An apparatus for testing the authenticity of coins, tokens or other flat metal articles includes a coin passage with a lower and an upper side wall. A coin moves in a condition of bearing against the lower side wall along the coin passage past at least one inductive measuring element having a coil (S). The coil (S) can be fed with a first current (I.sub.1) from a first current of voltage source (19) and a second current (I.sub.2) from a second current or voltage source (21). A capacitive element (C.sub.1) is connected between the coil (S) and the first current or voltage source (19) so that the coil(S) and the capacitive element (C.sub.1) form an impedance (Z.sub.1). The phase shift (.phi..sub.1) between the first current (I.sub.1) and the voltage across the impedance (Z.sub.1) serves as a criterion for acceptance or rejection of the coin.

Abstract: A coin mechanism includes a piezoelectric film sensor in contact with a coin debounce device. When a coin is inserted into the coin mechanism, the coin strikes the coin debounce device as it travels along a coin path. Micro-movement of the coin debounce device is sensed with the piezoelectric film sensor. The coin mechanism changes from a quiescent mode of operation to an active mode of operation in response to sensing the presence of the coin in the coin path. Coin recognition can then be performed. Overall power consumption of the coin mechanism can be reduced.

Abstract: A coin selector is provided which is adapted to electronically sample coins and compare the sampling data to stored data for genuine coins. The stored data can be preset or can be acquired and stored in memory by using a key coin. Data stored determines if a key coin is authentic and if it is, places the selector processor in a condition to accept and store new or modified data for determining the authenticity of other coins.

Abstract: A coin validator with an improved coin processing rate, performs primary validation testing on coins at a primary validation station as successive coins roll down a coin rundown path. Unacceptable coins pass to a coin reject path but coins found acceptable by the primary validation testing are deflected by a solenoid operated gate to a coin accept path. The acceptable coins pass a further sensor coil. Auxiliary coin testing is carried out by a microprocessor by analyzing the time taken for the coin to reach and move away form the further sensor. The microprocessor performs undertimer and overtimer routines FIGS. 3A, B and if the coin arrives within the under and overtimer ranges t.sub.1, t.sub.2, the coin is accepted. When the coin throughput rate is increased, the undertimer is switched off in order to permit the coin throughput rate for valid coins to be increased, without loss of security.

Abstract: The invention provides a money sorting method and unit that can detect such a counterfeit as foreign money for which material, outer diameter and other features are very similar to a genuine coin, and that can decrease damage caused by the continuous trial of entry of counterfeit money. Sensors detect the material of a coin entered from a coin entry section, and at the same time, the outer diameter of the coin is detected by three sensors with a highly accurate method utilizing time ratio, pattern on the surface of the rolling coin is detected by converting output of the sensors to a basic pattern, and genuineness of the entered coin is judged based on these detection results.

Abstract: The energy of the sound radiation caused by the impact of the coin to be analyzed upon a hard surface is split into different frequency bands, the energy of every such band is obtained and the ratios between them are then worked out, obtaining parameters that are then compared against values representing valid coins. The device includes a bank of filters (6, 7 and 8), integrators (9, 10 and 11) connected to the outlet of the filters and capable of being activated from a microprocessor (17) and an analogue-digital converter to which the output of the various integrators is then connected through a multiplexer.

Abstract: A coin diameter measuring circuit uses a pair of coils coupled in the feedback path of an oscillator so that the oscillator frequency depends on the inductances of the coils and the mutual inductance therebetween. The coils are switched between aiding and opposing configurations when the coin passes between them, the oscillator frequency in each configuration is measured, and the difference between the frequencies is determined to provide an indication of the mutual indictance of the coils and, thus, the diameter of the coin. Preferably, the diameter is determined by the difference between the measured mutual inductance with the coin present and the coin absent.

Abstract: A coin identification device for detecting a change in magnetic field due to eddy currents produced in a coin and identifying the coin on the basis of the detected change includes a path along which the coin moves, a sensor including two coils juxtaposed at a predetermined interval along the path and disposed such that a central axis of each of the two coils is in line with a direction perpendicular to an obverse or reverse of the coin moving along the path, and two magnetic impedance elements disposed respectively within the two coils to extend along the central axes of the two coils, and an identification circuit for outputting an identification signal for identification of the coin by differentially amplifying outputs of the two magnetic impedance elements.

Abstract: An arrangement for checking coins wherein the coins (1) move in the checking operation along a side wall (6) of a coin passage (2) and past two coil halves (4a, 4b) which are disposed opposite each other on both sides of the coin passage (2) and which are connected in series in phase opposition. The coin half (4b) which is disposed on the same side of the coin passage (2) as the side wall (6) is of lower resistance than the other coin half (4a) and preferably comprises stranded wire.

Abstract: A coin discriminator system having a massive body integrally incorporated into one of the side walls of a passage channel for coins and which projects slightly outwardly form the level of the side wall towards the passage channel. The rolling coin strikes the transducer to produce mechanical vibrations which are transformed into electrical vibrations by a transducer and an electronic device. The massive body has a curved or spherical surface in relation to the projecting section of the wall. The base of the passage channel through which the coins roll has a slant so that the coins rolling along the channel abut against the side wall of the channel in which the massive body has been positioned.

Abstract: A coin discrimination apparatus and method is provided in which an oscillating electromagnetic field is generated on a single sensing core. The oscillating electromagnetic field is composed on one or more frequency components. The electromagnetic field interacts with a coin, and these interactions are monitored and used to classify the coin according to its physical properties. All frequency components of the magnetic field are phase-locked to a common reference frequency. The phase relationships between the various frequencies are fixed, and the interaction of each frequency component with the coin can be accurately determined without the need for complicated electrical filters or special geometric shaping of the sensing core. In one embodiment, a sensor having a core, preferably ferrite, which is curved, such as in a U-shape or in the shape of a section of a torus, and defining a gap, is provided with a wire winding for excitation and/or detection.

Abstract: A coin validator is provided with at least two reference positions (U, D) for determining a diameter related characteristic of a coin being validated. In order to reduce the running to the testing station, the timing of a trailing point of the coin passing a first reference position (U) is used to determine the diameter related characteristic. Embodiments using optical inductive and piezo-electric sensors associated with the reference positions are disclosed. An inductive sensor for a coin validator comprises an elongate coil, which, when in use, is arranged such that the magnetic field is substantially constant across the width of the passageway. The use of coils of this type have the advantage of wrap around coils but enable the coin passageway to be shallower and be opened. A coin validator is described wherein the backwall of a coin passageway is movable to and fro so that the depth of the coin passageway can be adjusted.

Abstract: A selector device for selecting objects (1) inserted by way of payment into a dispenser of goods or services via an insertion orifice (10), the device comprising a transport member (100) provided with a housing (110) designed to receive the objects singly and suitable for bringing an object (1) placed in said housing (110) into a measurement zone (ZM) where sensors (301, 302, 303) are disposed for verifying conformity of the object (1). According to the invention, the selector device also comprises drive mechanisms (200, 210) suitable for imparting a non-reversible continuous movement to said transport member (100) along a path during which the housing (110) passes from an initial position (P1) of communication with the insertion orifice (10) to a final or waiting position (P2), while passing through the measurement zone (ZM) in continuous manner, the sensors (301, 302, 303) for verifying conformity receiving sampling signals sampling the movement of the transport member (100).

Abstract: A coin discrimination apparatus and method is provided in which an oscillating electromagnetic field is generated on a single sensing core. The oscillating electromagnetic field is composed on one or more frequency components. The electromagnetic field interacts with a coin, and these interactions are monitored and used to classify the coin according to its physical properties. All frequency components of the magnetic field are phase-locked to a common reference frequency. The phase relationships between the various frequencies are fixed, and the interaction of each frequency component with the coin can be accurately determined without the need for complicated electrical filters or special geometric shaping of the sensing core. In one embodiment, a sensor having a core, preferably ferrite, which is curved, such as in a U-shape or in the shape of a section of a torus, and defining a gap, is provided with a wire winding for excitation and/or detection.

Abstract: A disc ejector including a hopper for storing a multiplicity of deposited metal discs; a rotary disc for trapping these discs one by one and transporting them towards an exit; structure for forcing the discs out of the rotary disc one by one at the exit;a rotary sweeper for removing the discs from the rotary disc;structure for receiving the removed discs and guiding them to a predetermined reference point;a check device provided near the reference point for determining if the disc is genuine; anda gate for selecting true discs from false disks, wherein true and false discs are accordingly ejected from separate outlets.

Abstract: A parking meter contains both optical detection elements, to detect the presence and the diameter of inserted coins, and conventional coils which are inductively coupled to a passing coin and which load a RF oscillator. The optical detection information is used to control the sampling of the frequency of the oscillators which are loaded by the metal in the falling coins. This provides a synergistic way to combine optical detection with electromagnetic detection to achieve compact recognition templates which readily perform difficult discrimination. Addition of a temperature compensation algorithm makes the resulting system extraordinarily insensitive to temperature-dependent variation in the permeability of a falling coin.

Abstract: A method of classifying a test article as one of a plurality of acceptable denominations of articles of currency, comprising applying a statistical classification process which employs discriminant surfaces derived from previous test articles known to be valid or invalid and is arranged to distinguish therebetween, characterized by applying also an acceptance boundary test which limits the acceptance volume for each denomination so as to exclude forgeries for which the discriminant surfaces were not derived.

Abstract: A coin sorter has a circular sorting track with an upstanding rim. A diverter mechanism is located at the rim and may be actuated to move a selected coin away from the rim to an off-sort depression inwardly of the rim and then to an off-sort opening at the end of the depression. The diverter mechanism is actuated by a coin recognition system that includes an induction coil located beneath the track in advance of the diverter mechanism. Signals from the induction coil are read at spaced positions of a coin passing over the coil and compared with stored ranges of acceptable signals for coins of various denominations. The diverter mechanism is actuated to divert a coin to the off-sort opening when the signals for that coin do not fall within a range of acceptable values. The ranges of acceptable values can be established by calibrating the coin recognition system by processing a plurality of known acceptable coins of a denomination.

Abstract: A coin discrimination apparatus and method is provided. Coins, preferably after cleaning, e.g. using a trommel, are singulated by a coin pickup assembly configured to reduce jamming. A coin rail assists in providing separation between coins as they travel past a sensor. The sensor provides an oscillating electromagnetic field generated on a single sensing core. The oscillating electromagnetic field is composed of one or more frequency components. The electromagnetic field interacts with a coin, and these interactions are monitored and used to classify the coin according to its physical properties. All frequency components of the magnetic field are phase-locked to a common reference frequency. The phase relationships between the various frequencies are fixed, and the interaction of each frequency component with the coin can be accurately determined without the need for complicated electrical filters.

Abstract: An apparatus and method of validating coins involves taking two independent measurements of the tested item, and determining whether both measurements lie within respective ranges for a particular coin type, the range for at least one of the measurements being dependent upon at least one other measurement.

Abstract: Disclosed is a comparative type detector for a coin-collecting mechanism. The comparative type detector includes a movable slot way portion having parallelly arranged and downward open first and second slot ways, as well as a main slide way and a secondary slide way located below and aligned with the first and the second slot ways, respectively. The second slot way and the secondary slide way together define a space for positioning a sample coin therein, and the first slot way and the main slide way together define a passage for a coin inserted into the coin-collecting mechanism to pass therethrough. Electric eyes are fixedly mounted at front and rear ends of the first slot way respectively slightly higher and lower than a reference line which is defined by a line parallel to a bottom surface of the secondary slide way and tangent to a top point of the sample coin.

Abstract: A coin or banknote validator is calibrated to accept items of value by taking successive measurements of items and using them to update acceptability data which defines at least one acceptability criterion for testing. Each measurement is first checked against a suitability criterion, and is only used for updating the acceptability data if the suitability criterion is met. In this way, the acceptability data can be derived without storing all the individual measurements, while still rejecting those measurements which are statistically unsound. The suitability criteria is such that if a measurement differs from the current acceptability data by more than a predetermined amount, the criterion is not met. To avoid problems resulting from the first measurement being unsound, this first measurement is discarded if it does not lie within a predetermined range of the second measurement.

Abstract: A method of testing coins comprising at least taking two measurements of an unknown coin: and accepting said unknown coin as corresponding to a first coin type if the point defined by the measurements lies, in the space defined by the axes of the measurements, on a first side of a discriminant surface at which the Mahalanobis distances of the centers of the distribution of said first coin type and a second coin type are in a predetermined relationship, characterized in that said relationship corresponds (at least approximately) to equality of the sums of the respective Mahalanobis distances with respective predetermined constants at least one of which is non-zero.

Abstract: A coin discriminating apparatus includes a plurality of light emitting elements for projecting light onto a coin, a light receiver for optically detecting light reflected by the coin, and a scattering member, disposed on an opposite side of the coin from a light receiver, for scattering light emitted from the plurality of light emitting elements. The light receiver receives light reflected by the coin and light scattered by the scattering member and produces pattern data. The coin discriminating apparatus further includes a coin discriminator for detecting a diameter of the coin based on the pattern data produced by the light receiver, tentatively determining a denomination of the coin, and comparing the pattern data of the coin produced by the light receiver with reference pattern data of a coin of the tentatively determined denomination.

Abstract: A method of categorizing coins/tokens by energizing detect coils with a single pulse detecting the back EMF curve of the decaying pulse information, analyzing the unmodified back EMF curve to extract therefrom a number of variables and processing those variables to provide values proportional to the variables, and comparing the values of the coin/token to at least one of a number of reference values to determine into which of a number of predetermined categories the coin/token falls.

Abstract: Coin validation apparatus comprising a coin path (2, 5, 6); an impact element (14) disposed in the coin path to be contacted by a coin (10); an impact transducer (8) arranged to generate an output signal in dependence on vibration of the impact element (14); and control means (7) for determining a coin parameter based on the output signal; characterised in that the impact element (14) is shaped to create multiple impacts with a passing coin (10).

Abstract: A method for recognizing permitted and prohibited coins permits precise and trouble-free assignment of coins by a procedure in which, during a learning step, characteristic values of reference coins are determined without contact and the measured values of coins to be investigated are compared with the characteristic values. The measured values are determined during rolling of the coins through a chute (6). Light barriers (204a-e, 205a-e) which determine blocking times when the coins roll through are used for the measurement.

Abstract: A coin box monitoring circuit for use in pay telephones, providing coin detection, coin volume totalization, and full coin box signaling to the telephone central office. An included coin chute assembly has three channels that cause nickels, dimes, and quarters to pass through specific locations within each channel. Light sources and light detectors detect the passage of coins. A microprocessor is utilized to control the light sources, monitor the detectors, and volumetrically count the coins passing through the coin chute. On reaching a full condition, a microprocessor then controls a relay to signal that the predetermined coin box level has been reached.

Abstract: Methods and validation apparatus for achieving improved acceptance and rejection for coins, bills and other currency items. One aspect includes modifying item acceptance criteria by creating and defining three-dimensional acceptance clusters, the data for which are stored in look-up tables in memory associated with a microprocessor. A second aspect involves fraud prevention by temporarily tightening or readjusting item acceptance criteria when a potential fraud attempt is detected. A third aspect relates to minimizing the effects of counterfeit items such as slugs on the self-adjustment process for the item acceptance criteria. A final aspect relates to calculation of a relative value of the acceptance criteria in order to conserve memory space and minimize computation time.

Abstract: Apparatus for validating items of value is described. The apparatus includes a measurement circuit including an inductor, the complex impedance of which varies in accordance with the interaction between a test item of value and a magnetic field within which the inductor is located. Circuitry is provided for extracting first and second periodic signals from the measurement circuit, and a circuit is provided for timing the interval between corresponding portions of the first and second periodic signals. A processing element then determines the value of a parameter related to at least one of the real and imaginary parts of said complex impedance, as a measure of the validity of said test item, from the outputs of the timing circuit.

Abstract: In a coin detection system, a coin passes between conductive plates which form a capacitor, which provides part of the frequency controlling capacitance of an LC tuned oscillator circuit. The presence of a coin between the conductive plates alters the capacitance, and consequently alters the output frequency of the oscillator circuit. The oscillator output is supplied to the clock of a counter, optionally following frequency division in a frequency divider. The counter counts the number of clock pulses received in a 10 ms period, and the count value is provided to a microprocessor via a shift register. The count value will be a measure of the frequency of the output of the oscillator. The microprocessor uses the output to determine whether a valid coin has been received, and if so, what the denomination of the valid coin is.

Abstract: A coin diameter discriminating device wherein a coin is received in a coin transport mechanism which is rotated by a motor at an accurately controlled angular velocity. By such arrangement, the coin is carried along a predetermined path at an accurately controlled or regulated velocity past at least one optical sensor that provides a change of state output upon detecting an edge of the coin. The sensor is arranged to start a time counter that is stopped by a predetermined reference event such as the coin transport mechanism having rotated to a predetermined angular orientation. The time count in the counter therefore corresponds to the angular orientation of the coin transport mechanism at the time of detecting the coin edge, which also accurately corresponds to the diameter of the coin. The time count is then compared to corresponding time count ranges each of which relates to known standards of an acceptable coin denomination.

Abstract: In a process for the classification of an article such as a banknote described by of a k-dimensional feature vector (AGF) which is prepared by a preliminary processing system (7), a test specimen is either assigned to one of n target classes or classified as a counterfeit. For the n target classes n recognition units (15.1 to 15.n) are used, exactly one of the n target classes being recognisable by one recognition unit (15.j) using a respective feature vector (AGFj) prepared for that class. A recognised target class is transmitted by an output unit (14) to a service system (11). There are assigned to a target class in a learning phase several k-dimensional target vectors which are compared with the feature vector during the classification. The recognition unit (15.j) is advantageously a neural network, one neuron comparing the feature vector (AGFj) with one of the target vectors.

Abstract: A coin detection device includes one or more optical sensors positioned along a coin path and capable of detecting movement of a coin thereby, a coil energizable to generate an electromagnetic field in the region of the coin path, a processor connected to the optical sensor or sensors so as to receive signals therefrom and connected to a detector which is capable of detecting the coin as it enters and leaves the region of the coil, the processor is operable to establish an optical size time based upon signals received from the optical sensor or sensors and a magnetic size time based upon signals received from the detector and to further establish a ratio of the magnetic size time to the optical size time, or magnetic to optical size ratio, the established ratio is then evaluated to determine if the tested coin is a valid coin.

Abstract: A device for sensing predetermined characteristics of an object such as a coin in order to determine the validity or genuineness of the coin and in some cases also the size and/or denomination of the coin, the device including a combination of optical sensors and an associated electro-magnetic sensors which operate together to expose the coin in different positions to the field produced by the electro-magnetic sensors so that if there are variations in the coin such as variations in the materials from with the coin is made these can be sensed and used to determine the coin's validity.

Abstract: In a coin handling apparatus, a single sensor (30) detects impacts of the coin at different positions within the apparatus, and uses the output to determine the route taken by the coin through the apparatus, and the speed of the coin.

Abstract: A coin discrimination sensor and coin handling system for discriminating among desired and undesired coins, comprised of an excitation coil for producing an alternating magnetic field. These alternating magnetic fields couple to the desired and undesired coins to induce eddy-currents. The sensor also is comprised of a detection coil for detecting eddy-currents from desired and undesired coins. The detection coil produces a differential voltage corresponding to the composition of the desired and undesired coins being sensed.

Abstract: Money items are validated by determining whether n measured properties lie within an n-dimensional ellipse associated with a particular money item. The center of the ellipse lies on the statistical mean of the property measurements for that particular item, and each axis is related to the standard deviation for a respective property measurement.

Abstract: Money items are validated by determining whether n measured properties lie within an n-dimensional ellipse associated with a particular money item. The center of the ellipse lies on the statistical mean of the property measurements for that particular item, and each axis is related to the standard deviation for a respective property measurement.

Abstract: A coin validator has a sensor circuit including two sensor coils each of small diameter, the coils being positioned such that they are passed in succession by a coin moving through a test section of the validator. The sensor circuit derives a signal representing the difference between the coil outputs so that bimetallic coins having a different outer ring material from the core material are easily detected.

Abstract: A differential type sensing unit which includes a winding core having a winding shaft is described. In one embodiment, a post extends from the winding shaft and is located intermediate first and second winding ends of the winding shaft. The post facilitates reversing the winding direction of a conductor wound on the winding shaft. The conductor is wound such that the sensing unit includes a first sensing coil and a second sensing coil formed in a series opposing configuration. The sensing unit may be integrated with a driving unit to include driving coils formed over the top of the sensing coils.

Abstract: A method for identifying metallic coins and tokens, comprising: applying an input signal to an ac-bridge; bringing a coin/token in the vicinity of one arm of the ac-bridge; sensing an output signal of the ac-bridge; and associating the output signal with presence of the coin/token in the vicinity of the arm of the ac-bridge.

Abstract: An electronic coin analyzer having a low profile that is especially useful for applications previously limited to mechanical devices includes a test coin path aligned with a coin-receiving opening in a faceplate and a rejected coin path laterally offset from the test coin path and aligned with a coin reject slot in the faceplate. An opening is defined between the test coin path and the rejected coin path that is larger than an acceptable coin/token. A coin deflecting surface is selectively positioned in the test coin path at the opening by an electromagnetic actuator in order to laterally deflect coins rolling along the test coin path toward the rejected coin path. Coins not deflected continue rolling past the opening, as a result of inertia, to an accepted coin path. An electronic control is provided having a test coin sensor and a circuit which causes the actuator to withdraw the deflecting surface from the test coin path in response to an acceptable coin.

Abstract: Methods and validation apparatus for achieving improved acceptance and rejection for coins, bills and other currency items. One aspect includes modifying item acceptance criteria by creating and defining three-dimensional acceptance clusters, the data for which are stored in look-up tables in memory associated with a microprocessor. A second aspect involves fraud prevention by temporarily tightening or readjusting item acceptance criteria when a potential fraud attempt is detected. A third aspect relates to minimizing the effects of counterfeit items such as slugs on the self-adjustment process for the item acceptance criteria. A final aspect relates to calculation of a relative value of the acceptance criteria in order to conserve memory space and minimize computation time.

Abstract: The invention relates to a coin/token separator comprising:(a) an inlet through which coins/tokens (C) pass;(b) at least two outlets (29, 30) to receive separated coin/tokens (C); and(c) a separator interposed between (a) and (b) including:(i) an arm (21) pivotable on a floating pivot (28) and movable between a first position in which the coin/token is directed towards one of the outlets (28) and a second position in which the coin/token (C) passes to another of the outlets (30), the arm (21) being normally biased into the first position; and(ii) a solenoid (18) actuated by a signal to move the arm (21) from the first position to the second position.

Abstract: A coin validating system typically used in a coin operated machine electrically couples a stationary coin to the tuning coils of an oscillator circuit. While the coin is in a stationary position and the oscillator is tuned to a first rest frequency, the output frequency and output amplitude of the oscillator is measured. The metal coin will increase the signal frequency from its rest frequency and will decrease the signal amplitude from its rest amplitude. While the coin is stationary, frequency and amplitude are measured and compared with expected parameters of a valid coin. If a match is made, the rest frequency of the oscillator circuit is changed. At the second test frequency, signal frequency and amplitude are measured and compared with expected frequency and amplitude parameters for a valid coin. Only if a match is made at both the high frequency and the low frequency is an accept gate actuated.

Abstract: An unacceptable coin removing apparatus for a coin handling machine includes a rotatable disk for receiving coins deposited into the coin handling machine and feeding coins one by one into a coin passage provided with a reference guide rail and a facing guide rail facing the reference guide rail, transporting belts for transporting coins in the coin passage, sensors for detecting coins, a first projecting member which can be projected from the reference guide rail into the coin passage, a second projecting member which can be projected from the facing guide rail into the coin passage, a coin collecting opening and a controller for controlling the operation of the first projecting member, the second projecting member, the transporting belts and the rotatable disk. When the sensors detect an acceptable coin, the controller does not actuate the first and second projecting members.

Abstract: For the classification of a pattern in particular on a banknote or a coin, a receiving system detects, by a measurement procedure, vectors of a test item, a pre-processing system transforms the measured vectors into local feature vectors ALCi(l) and a learning classification system carries out a plurality of testing operations. A first activity compares in a first testing operation each of the local feature vectors ALCi(l) to a vectorial reference value. It is only if the first testing operation takes place successfully that the first activity, by means of first estimates which are stored in a data base, links the local feature vectors ALC(l) to provided global line feature vectors AGIi.

Abstract: A method for calibrating a coin checking device includes inserting a calibrating module into a coin passage. The coin passage contains at least one coin sensor for determining a coin's physical features. The calibrating module generates measuring signals which simulate an acceptable coin's presence. The measuring signals are received by the at least one coin sensor which in turn outputs sensor signals. The measuring signals and the sensor signals are used to calculate a calibration factor for the coin checking device.

Abstract: A coin validator which discriminates valuable coins includes a coin path along which the coins roll. A leaf spring is fixed at one end and has a spring member which projects into the coin path at the other end when the leaf spring is in a rest position. The leaf spring oscillates when the spring member is struck by a rolling coin. An evaluation circuit produces a timing signal as a function of the elapsed time between the striking of the spring member by the rolling coin and the time when the spring member first approaches the rest position after being struck. A memory stores reference values corresponding to valuable coins and a comparator compares the timing signal to the reference values for discriminating valuable coins.