U.S. patent number 3,739,895 [Application Number 05/171,922] was granted by the patent office on 1973-06-19 for method and apparatus for testing coins employing dimensional categorizing means.
Invention is credited to Guy L. Fougere, John L. Rothery.
United States Patent |
3,739,895 |
Fougere , et al. |
June 19, 1973 |
**Please see images for:
( Certificate of Correction ) ** |
METHOD AND APPARATUS FOR TESTING COINS EMPLOYING DIMENSIONAL
CATEGORIZING MEANS
Abstract
A coin selector and a method of coin selection are disclosed
which utilize a coin presence sensor array including a primary
sensor and a series of secondary sensors, which together with
combinatorial circuitry provide signals indicative of the size
category of a coin and signals indicative of the acceptance ratio
of the coin and compare the signals with predetermined values for
acceptable coins.
Inventors: |
Fougere; Guy L. (Lincoln,
MA), Rothery; John L. (Marblehead, MA) |
Family
ID: |
22625654 |
Appl.
No.: |
05/171,922 |
Filed: |
August 16, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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91871 |
Nov 23, 1970 |
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812127 |
Apr 1, 1969 |
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Current U.S.
Class: |
194/325;
194/339 |
Current CPC
Class: |
G07D
5/02 (20130101); G07D 5/08 (20130101) |
Current International
Class: |
G07D
3/00 (20060101); G07D 5/08 (20060101); G07D
3/14 (20060101); G07D 5/00 (20060101); G07f
003/02 () |
Field of
Search: |
;194/99,102,1R,1A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tollberg; Stanley H.
Parent Case Text
This application is a continuation-in-part of our copending
application Ser. No. 91,871, filed Nov. 23, 1970, which is a
continuation-in-part of our application Ser. No. 812,127, filed
Apr. 1, 1969, both now abandoned.
Claims
I claim:
1. A device for determining the authenticity and denomination of
coins of a plurality of acceptable denominations comprising,
a passageway along which coins may travel,
means for causing a magnetic field to move relative to a coin in
the passageway,
at least two coin presence sensors spaced apart in the direction of
coin travel, the distance between the sensors being such that when
the edge of a coin of the largest acceptable diameter of one
acceptable denomination is at a first sensor the chord of that coin
along the line between the sensors is shorter than the spacing of
the sensors and when the edge of a coin of the smallest acceptable
diameter of another acceptable denomination is at the first sensor
the chord of that coin along the line between sensors is longer
than the spacing of the sensors,
means to establish the coin path in the region of the sensors,
means to measure the duration of concurrent presence of a coin at
at least two of the sensors,
means to measure the interval subsequent to the presence of a coin
at the first sensor and prior to the arrival of the coin at a
second sensor,
means to compare each of the measurements with standards for
acceptable coins, and
means to produce an output signal if a measurement is within a
predetermined tolerance of a standard.
2. A device for determining the authenticity and denomination of
coins of a plurality of acceptable denominations comprising,
a coin passageway,
means for causing a magnetic field to move relative to a coin in
the passageway,
an array of coin presence sensors down the passageway from at least
a portion of the magnetic field,
the array including a primary sensor and secondary sensors each
spaced from the primary sensor and secondary sensors each spaced
from the primary sensor distances less than a given chordal
dimension of an acceptable denomination coin and greater than the
chordal dimension of the next smaller acceptable denomination
diameter coin,
means to determine the coin path in the region of the array,
means to generate a signal denoting the occlusion of each
sensor,
a logic circuit using the signals to determine whether a coin is
large enough to be particular acceptable denomination and small
enough not to be the next larger acceptable denomination, the logic
circuit having an output representative of the denomination
determined,
means to measure the duration of concurrent signals,
means to measure the interval between the end of a signal and the
beginning of another signal,
means to compare each of the measurements with standards for
acceptable coins, and
means to produce an output signal if a measurement is within a
predetermined tolerance of a standard.
3. A device for determining the authenticity and denomination of
coins of a plurality of permissible denominations comprising,
a coin track,
first means for comparing a value related to a chordal dimension of
the coin with predetermined values, and
second means for comparing a value related to the coin velocity and
chordal dimension with predetermined values,
wherein the first means includes a primary sensor and two or more
secondary sensors, each secondary sensor being spaced by a
different distance than the other secondary sensors (a) from the
primary sensor in the direction of coin travel and (b) normal to
the crack transversely of the direction of coin travel, at least
one of the sensors being spaced from the track in a direction
normal to the track a distance less than the diameter of the
smallest permissible coin,
a first circuit to determine if said chordal dimension is at least
equal to the distance between the primary sensor and one of the
secondary sensors, and
wherein the second means includes means for producing a magnetic
field in a zone through which the coin passes before the coin
reaches at least one of said sensors, and
a second circuit for examining the time that a coin, whose said
chordal dimension is at least equal to the distance between the
primary and one of the secondary sensors, is sensed concurrently by
those sensors, and a coin, whose said chordal dimension is less
than the distance between the primary sensor and one of the
secondary sensors, takes to travel between those sensors.
4. A device as defined in claim 3 wherein the distance between at
least one secondary sensor and the primary sensor is greater than
the maximum acceptable predetermined dimension of a permissible
coin.
5. A device as defined in claim 3 wherein the distance between at
least one secondary sensor and the primary sensor is less than the
maximum acceptable predetermined dimension of a permissible
coin.
6. A device as defined in claim 3 wherein the distance between each
secondary sensor and the primary sensor is greater than the maximum
acceptable predetermined dimension of one permissible coin and less
than the minimum acceptable predetermined dimension of another
permissible coin.
7. A device as defined in claim 3 wherein, for a coin whose said
chordal dimension is less than the distance between the primary and
any of the secondary sensors, the second circuit means examines the
time interval between the instant the coin ceases being sensed by
one of said primary and secondary sensors until it is sensed by the
other of said primary and secondary sensors.
8. A device as defined in claim 3 including a third circuit for
comparing the time with predetermined values representative of
acceptable coins, the third circuit means providing a signal
indicative of the denomination of acceptable coins.
9. A device as defined in claim 3 including means for sensing the
arrival of a coin at a point prior to said first means and said
second means and including means for enabling the first and second
circuits to perform their intended functions, the enabling means
being actuated by the arrival sensing means.
10. A device as defined in claim 3 wherein the second circuit
includes a signal gate responsive to the primary sensor and the
secondary sensors, a signal source and a counter, the signal from
the signal source being directed to the counter through the signal
gate, the signal received by the counter being representative of
the combined property of the coin as it travels between the
sensors.
11. A device as defined in claim 3 wherein the first circuit
includes at least a first and a second coincidence gate, the first
coincidence gate being responsive to signals indicating concurrent
coin presence at the primary sensor and a secondary sensor, and the
second coincidence gate being responsive to signals indicating
initial coin presence at one of the sensors and the concurrent
absence of a coin at the primary sensor and a secondary sensor, the
first gate when enabled indicating the existence of a coin in the
device within the group of coins whose said chordal dimensions is
at least equal to the distance between the primary and secondary
sensors and the second gate when enabled indicating the existence
of a coin in the device within the group of coins whose said
chordal dimension is less than the distance between the primary and
secondary sensors.
12. A device as defined in claim 3 wherein the second circuit
includes a signal gate responsive to each of the coincidence gates,
a pulse source and a counter, the signal from the pulse source
being directed to the counter through the signal gate, the signal
received by the counter being representative of the duration of
presence signals, the device including means for receiving
information from the counter and from the coincidence gates and for
comparing such information with predetermined values characteristic
of acceptable coins, and means for providing a signal
representative of the denomination of the coin if said values are
equal to the predetermined values.
13. A device as defined in claim 3 including at least a first and
second secondary sensor and where the first circuit comprises
first, second, third and fourth coincidence gates;
the first coincidence gate being responsive to signals indicating
concurrent coin presence sensing by the first secondary sensor and
the primary sensor;
the second coincidence gate being responsive to signals
concurrently indicating a concurrent coin presence sensing by the
second secondary sensor and the primary sensor, and the absence of
concurrent coin presence sensing by the first secondary sensor and
the primary sensor;
the third coincidence gate being responsive to signals indicating
absence of coin presence sensing by the first secondary sensor and
concurrent coin presence sensing by the second secondary sensor and
primary sensor;
and the fourth coincidence gate being responsive to signals
indicating absence of coin presence sensing by the first secondary
sensor, absence of concurrent coin presence sensing by the second
secondary sensor and primary sensor and previous coin presence
sensing by the second secondary sensor, each of the coincidence
gates providing a signal when it is enabled.
14. A device as defined in claim 13 wherein the second circuit
includes a signal gate responsive to each of the coincidence gates,
a pulse source and a counter, the signal from the pulse source
being directed to the counter through the signal gate, and
including means for receiving output information from the counter
and from the coincidence gates, means for comparing such
information with predetermined values characteristic of acceptable
coins, and means for providing a signal representative of the
denomination of the coin if said values are within a predetermined
tolerance of predetermined values.
15. A method for determining the authenticity and denomination of
coins of a plurality of permissible denominations comprising,
propelling a coin at a velocity influenced by the motion relative
thereto of a magnetic field,
subsequent to affecting the velocity of the coin, passing the coin
by at least two coin presence sensors spaced apart in the direction
of coin travel, the distance between the sensors being such that
when the edge of a coin of the largest acceptable diameter of one
acceptable denomination is at a first sensor the chord of that coin
along the line between the sensors is shorter than the spacing of
the sensors and when the edge of a coin of the smallest acceptable
diameter of another acceptable denomination is at the first sensor
the chord of that coin along the line between sensors is longer
than the spacing of the sensors,
measuring the duration of concurrent presence of a coin at least
two of the presence sensors,
measuring the interval subsequent to the presence of a coin at a
first sensor and prior to the presence of the coin at a second
sensor,
comparing each of the measurements with standards for acceptable
coins, and
producing an output signal if a measurement is within a
predetermined tolerance of a standard.
16. A method for determining the authenticity and denomination of
coins of a plurality of permissible denominations comprising,
affecting the velocity of a coin by causing the coin to move with
respect to a magnetic field,
subsequent to affecting the velocity of the coin, passing the coin
by an array of sensors at least two of the sensors of the array
being spaced apart in the direction of coin travel, the distance
between the sensors being such that when the edge of a coin of the
largest acceptable diameter of one acceptable denomination is at a
first sensor the chord of that coin along the line between the
sensors is shorter than the spacing of the sensors and when the
edge of a coin of the smallest acceptable diameter of another
acceptable denomination is at the first sensor the chord of that
coin along the line between sensors is longer than the spacing of
the sensors,
generating a signal denoting the occlusion of each sensor of the
array,
measuring the duration of concurrent signals,
measuring the interval between the end of a signal and the
beginning of another signal,
comparing each of the measurements with values representative of
acceptable coins, and
producing an output signal if a measurement is within a
predetermined tolerance of a value.
17. The method of claim 16 wherein signals are also introduced to a
logic circuit which operates on the signals to produce an output
signal representative of the denomination of the coin.
Description
This invention relates to coin selectors and, more particularly, to
a system for determining the denomination of coins and for ejecting
undesired and counterfeit coins.
Throughout this specification and in the appended claims, the term
"coin" is intended to mean genuine coins, tokens, counterfeit
coins, slugs, washers, and any other item which may be used by
persons in an attempt to use coin-operated devices.
An "acceptable" coin is an authentic coin of the monetary system in
which the device is intended to operate and of a denomination which
the device is intended selectively to receive for value.
It is known to utilize two properties of a coin to determine its
denomination. The result of that determination is in many instances
indicative of the coin's authenticity. Devices have been proposed
in which a coin entering the device is acted upon by a magnetic
field provided by a magnet mounted adjacent to a coin passageway
and the coin's motion relative to the magnetic field causes eddy
currents to flow within the coin. Associated with these eddy
currents are magnetic fields which interact with the magnet,
producing a force opposing the coin's motion through the magnetic
field. The effect of an electrically conductive, non-ferromagnetic
coin passing through a stationary magnetic field is the retardation
of the coin in an amount directly proportional to the coin's
electrical conductivity divided by its density, called the
acceptance ratio. Therefore, the coin's velocity sensed downstream
of the magnetic field is one examinable indicium of coin
authenticity and denomination. The length of a chord of the coin is
a second examinable indicium. By comparing the results of the
examination of these indicia with corresponding known values for
authentic coins of particular denominations desired to be accepted,
determinations of acceptability are made.
It is one objective of this invention to provide a coin selector
having substantially improved reliability and effectiveness in
sensing the denomination of coins and which is economical to
manufacture and maintain.
Another objective of this invention is to provide a coin selector
having the capabilities of accepting a large number of permissible
coin denominations and of being able to be modified easily on site
to permit acceptance of additional or different coins.
In accordance with the present invention, the examinations are made
by coin presence sensors such as photoelectric devices which
transmit electrical output signals to a combinatorial circuit where
the determination is made. If the coin is acceptable, a signal
indicative of the denomination is transmitted to an accumulator and
to the device being operated, such as a vending machine.
In a device designed to accept three or four coins, for example,
three sensors can be utilized in a two-step examination process.
The sensors include a primary sensor and a pair of secondary
sensors spaced from the primary sensor in the direction of coin
movement, the secondary sensors being spaced apart both in the
direction of coin movement, and upwardly from the coin support
track. In the first examination phase, the sensors, together with
the combinatorial circuit, classify all coins offered as falling in
one of five size categories, namely, (a) coins large enough to
concurrently cover all three sensors; (b) coins only large enough
to cover the third at a time when at least one of the others is
uncovered; (c) coins large enough to cover concurrently the primary
sensor and one of the two secondary sensors but not large enough to
cover, at any time, the other secondary sensor; (d) coins not large
enough to cover the higher of the secondary sensors but large
enough to cover the other secondary sensor and primary sensor,
successively but not concurrently, and (e) coins not large enough
to cover any of the sensors.
The second phase of examination determines if a function dependent
upon both the coin's velocity and chordal length is within
prescribed limits. This is accomplished by causing the
combinatorial circuit to measure the duration of occlusion of
sensors. The circuit compares the duration of the signals with
predetermined values representative of acceptable coins and, if the
comparison is favorable, produces a signal indicating that the coin
in the device is deemed acceptable denomination.
In the drawings:
FIG. 1 is a front elevational and schematic diagram of a coin
selector device for determining the authenticity and denomination
of a coin formed in accordance with this invention;
FIG. 2 is a schematic elevational diagram of a sensor array
illustrating the location of the individual sensors with respect to
various representative coin diameters;
FIG. 3 is a diagram of a combinatorial circuit used in conjunction
with the sensor array of FIG. 2 to provide the logic determination
required in the evaluation of coins; and
FIG. 4 is a sensor signal sequence table illustrating the operation
of the individual sensors for four representative coins.
It should be noted that the drawings are not intended to be
dimensionally proportionate or scale representations of the devices
illustrated. It will be clear to those skilled in the art that,
whereas the invention has been described in terms of AND and OR
logic elements, alternative logical elements may be used without
departing from the invention. Similarly, the word signal has been
used in most cases to represent the relatively high output voltage
of certain devices having two output voltages but the invention is
not limited to the disclosed use of such signals.
DETAILED DESCRIPTION
Coin Selector Device
In FIG. 1, there is illustrated a coin selector device 10 having a
coin support track 12 and two inclined surfaces 14, 16, the two
inclined surfaces together making up a meander path. The device 10
also is provided with a solenoid controlled coin arrestor 18, a
magnetic coin scavenger 19, an eddy current brake magnet 20 and an
array of coin presence sensing means 21 for sensing various
properties of a coin to determine the coin's acceptability. The
selector device also includes a coin acceptance gate 22, a coin
acceptance passageway 23 and a coin rejection passageway 24.
A coin is inserted into the coin selector device 10 by dropping it
into a funnel shaped entrance 26 from which it drops downwardly
toward the support track 12 the coin being slowed in its travel by
the meander path surfaces 14, 16 and the coin is brought to rest on
the support track 12 by the arrestor 18 which constitutes a
mechanical stop. As the coin passes down toward the track 12, it
passes a coin arrival sensor 28 which senses the presence of a coin
in the system and initiates operation of various electronic
components described below.
Many sensing devices are suitable, such as mechanical or inductive
switches, but a preferred sensor is a photoelectric device, for
example, a photosensitive transistor operating in conjunction with
a light source on opposite sides of the coin passageway with the
sensor providing signals indicative of when the sensor is occluded
or obscured.
While the coin is held in a stationary position on the support
track 12 by the arrestor 18, it resides adjacent to the magnetic
coin scavenger 19 which may be a permanent magnet or other means
known in the art for removing ferromagnetic coins or objects from
the system, so they do not become trapped by its other magnets. At
a predetermined period of time after the coin is sensed by the coin
arrival sensor 28, the solenoid (not shown) which controls the
arrestor 18 is actuated to remove the arrestor from the path of the
coin permitting the coin to pass down the track. If the coin is
ferromagnetic, it will be prevented from moving down the track by
the magnet 19. Any one of several known mechanisms can be used to
remove the ferromagnetic coin from the system, for example, the
magnetic coin eliminator described in U.S. Pat. application Ser.
No. 66,126, filed Aug. 21, 1970 as a continuation of Ser. No.
808,943, filed Mar. 20, 1969.
A coin released by arrestor 18 is accelerated and decelerated in a
manner which is dependent upon the coin's physical properties. In
this embodiment when a coin is released it proceeds to roll down
the support track 12 and passes through a magnetic field produced
by the magnet 20. The magnet 20, a permanent magnet or an
electromagnet is located on one side of the support track 12. The
magnetic field circuit is completed by a second magnet or a plate
(not shown) of ferromagnetic material such as mild steel which may
be located directly opposite the magnet 20 in order to provide a
field across the passageway through which the coin passes. The eddy
currents induced in the coin as the coin moves through the magnetic
field magnetically interact with the magnet 20, producing a
retarding force on the coin. The magnitude of the retarding force
exerted on the coin is directly proportional to the velocity of
entry of the coin into the magnetic field and the coin's
conductivity. The preferred strength of the magnetic field is such
as to reduce the velocity of the coins intended to pass through the
system by between 10 and 50 per cent. The change in coin velocity
as it passes through the magnetic field is an indicia of the coin's
acceptability.
After the coin passes by magnet 20, it passes between a light
source (not shown) on one side of the track 12 and a sensor array
21 on the other. Here a determination the coin's acceptability and
denomination is made. This sensor array is described in greater
detail below. After the coin passes the sensor array 21, it rolls
off the track 12 and drops downwardly toward a coin acceptance gate
22. The gate is solenoid actuated and extends into the coin
passageway. If the coin sensor array together with logic circuitry
discussed hereafter determines that the coin passing through the
system is not acceptable, the gate is not removed from the
passageway and the coin bounces from the gate 22 into the rejection
passageway 24. If the sensors and logic system determines that an
acceptable coin has passed through the system, a signal is
transmitted to the gate solenoid which retracts the gate 22 from
the coin passageway and the coin drops into the acceptance
passageway 23.
Coin Sensor Array
Turning now to FIG. 2, the coin sensor array 21 is schematically
illustrated so that the principle of its operation may be
described. In the following description, coin movement in FIG. 2
will be assumed to be from the viewer's left to right.
The sensor array 21 is primarily designed for the recognition of at
least four different denomination coins which, for simplicity of
discussion, shall be considered to be the 5, 10, 25 and 50 cent
pieces of U.S. coinage. The coin sensor array 21 comprises a
primary sensor 42 and a series of secondary sensors 44 and 46
spaced from the primary sensor 42, with the entire array 21 mounted
in a fixed relationship to the coin support track 12 which supports
the edge of the coins being examined. Secondary sensor 46 is spaced
from the primary sensor 42 by a distance which is (1) greater than
the chord length along the line between sensors 42 and 46 of the
largest coins of the acceptable denomination of smallest diameter,
namely a 10 cent piece, when that coin is resting in the track
between the sensors with one edge just barely obscuring sensor 42;
and the largest coins of the acceptable denomination of smallest
diameter (2) less than the chord length along that line of the
smallest coins of the acceptable denomination of the second
smallest diameter, namely a 5 cent piece, when that coin is resting
on the track between the sensors with one edge just barely
obscuring sensor 42. The location of sensors 42 and 46 above the
coin support track 12 is less than the diameter of the smallest
acceptable coin of all, namely the smallest acceptable 10 cent
piece.
The second secondary sensor 44 is spaced from the primary sensor 42
by a distance which is (1) greated than the chord length along the
line between sensors 42 and 44 of the largest coins of the
acceptable denomination of second largest diameter, namely the 25
cent piece, when that coin is resting on the track between the
sensors with one edge just barely obscuring sensor 42; and (2) less
than the chord length along that line of the smallest coins of the
acceptable denomination of largest diameter, namely the 50 cent
piece, when that coin is resting on the track between the sensors
with one edge just barely obscuring sensor 42. The location of
sensor 44 above the coin support is greater than the diameter of
the largest coins of the acceptable denomination of second smallest
diameter, the 5 cent piece, and less than the diameter of the
smallest coins of the acceptable denomination of second largest
diameter, the 25 cent piece.
It can be seen that the three sensors 42, 44 and 46 are arrayed so
that sensor 44 is never obscured by either 10 or 5 cent pieces but
is obscured by both 25 and 50 cent pieces and, that sensors 42 and
44 can be concurrently obscured (i.e.: sensor 42 will be obscured
during part of the period when sensor 44 is obscured by the 50 cent
piece but not by the 25 cent piece. Likewise, sensor 46 is obscured
by all acceptable coins and the sensors 46 and 42 are concurrectly
obscured by the three larger coins, the 5, 25 and 50 cent pieces,
but are not concurrently obscured by the smallest acceptable coin,
the 10 cent piece. By the use of a relatively simple logic system
described below, the information provided by these three sensors
can be used to classify all coins into five categories as follows:
(a) coins large enough to concurrently cover all three sensors; (b)
coins only large enough to cover a selected to of the three sensors
concurrently but large enough to cover the third at a time when at
least one of the others is uncovered; (c) coins large enough to
cover concurrently the primary sensor and one of the two secondary
sensors but not large enough to cover, at any time, the other
secondary sensor; (d) coins not large enough to cover the higher of
the secondary sensors but large enough to cover the other secondary
sensor and primary sensor, successively but not concurrently and
(e) coins not large enough to cover any of the sensors.
COMBINATORIAL CIRCUIT
Coin Size Categorization Circuit
While many different combinatorial circuits or logic systems can be
used to provide the desired results a specific circuit or logic
system 47 is illustrated in FIG. 3 which should be read in
combination with the sensor signal sequence table shown in FIG. 4.
The logic system utilizes four coincidence gates 48, 50, 52, 54 and
two bi-stable multivibrators or flip-flops 56, 58. Each gate
represents one acceptable coin and is set to produce an output
signal when all of its input signals are in the high state. Each
gate is responsive to signals from the three coin property sensing
array sensor 42, 44, 46, as well as signals from the flip-flop 56.
For illustrative purposes, the signals from the sensors are
considered to be "high" when the sensors are lighted and not
obscured, and "low" when they are obscured by a coin.
Examining first the 50 cent piece coincidence gate 48, it can be
seen that gate 48 will produce a low signal only when a coin large
enough to obscure all three sensors 42, 44, 46 passes through the
system. The output from each sensor 42, 44, 46 is directed through
an inverter 60, 62, 64, respectively, which then leads to the
inputs of the gate 48. The fourth input to the gate 48 comes from
the flip-flop 56 which is set by a signal from the sensor 44.
Before a coin obscures the sensors, the sensors produce a high
signal which results in the impressing of a low signal, because of
the inverters 60, 62, 64, on the input of the gate 48. Furthermore,
the flip-flop 56, which is reset by the entry of a coin into the
system such as by a signal from the coin arrival sensor 28, will
not provide a proper signal on the input to the gate until the
sensor 44 is covered setting the flip-flop 56. As a large coin
passes down the support track 12 after passing the eddy current
magnet, it first covers sensor 44 which sets the flip-flop 56 to
provide the desired high signal on the input lead 66 of the gate 48
as well as producing the enabling high signal, because of the
inverter 62, on the input lead 68. The coin then obscures sensor 46
producing a high signal, because of the inverter 64, on the lead 70
and then obscures sensor 42 producing a high signal on the lead 72
because of inverter 60. The condition of four simultaneous high
signals on the inputs to the gate 48 occurs only when all three
sensors are simultaneously obscured (see FIG. 4) resulting in the
generation of a low signal on the output lead 74 of the gate 48
until the trailing edge of the coin passes the first sensor 44.
Therefore, a low signal on the output lead 74 indicates that a coin
large enough to cover all three sensors simultaneously has passed
the sensor array 21. This coin size category includes 50 cent
pieces.
Similarly, it can be seen that the only time all four input leads
of coincidence gate 50 are high is when the coin is large enough to
cover sensor 44, thus triggering the flip-flop 56, and large enough
to cover the sensors 42 and 46 concurrently but not large enough to
cover the sensor 44 during the time that sensors 42 and 46 are
covered. This is because the output from sensor 44 is fed directly
to the gate 50 rather than through the inverter 62 whereas the
output from the sensors 46 and 42 are fed to inverters 64 and 60
respectively before going to the gate 50.
Looking now at the coincidence gate 52, representing a coin size
category which includes the 5 cent piece, a high signal will be
produced on input lead 76 coming from the flip-flop 56 only when
the flip-flop 56 had not been set by a coin obscuring the sensor 44
since the output from the flip-flop 56 to the gate 52 is opposite
to the one that is fed to the coincidence gates 48 and 50.
Furthermore, it can be seen that the output signal from the sensor
44 goes directly to the input lead 78 rather than through the
inverter 62 so that a high signal exists on lead 78 only when
sensor 44 is not obscured. Input leads 80 and 82 representing
sensors 46 and 42 respectively lead to those sensors through
inverters 64 and 60 respectively thus experiencing simultaneous
high signals only when those sensors are obscured concurrently.
A similar analysis of coincidence gate 54 shows that it will
receive four high input signals only when sensor 44 has not been
obscured at all and sensors 42 and 46 are not concurrently
obscured. Coincidence gates 52 and 54 have a fifth input, namely,
inputs 84, 86 derived from flip-flop 58. The purpose of this input
is to indicate that a coin has passed through the system which has
a diameter at least equal to the height of the sensor 46 above the
track. Since gate 54 is enabled when none of the three sensors 42,
44, 46 are covered, it is appreciated that that condition also
exists when no coin passes through the system. To avoid this
ambiguity, the flip-flop 58 is reset by a coin entering the system
by means of the arrival sensor 30 to produce a low signal on the
inputs 84, 86 and, when sensor 46 becomes obscured by a coin, the
flip-flop 58 is set and produces a high signal on the inputs 84, 86
thus enabling the gates 52, 54 if the other conditions are met.
Therefore, a low signal on the output lead 92 of gate 54 indicates
that a coin large enough to obscure sensor 46 but not sensor 44 and
not large enough to obscure sensors 46 and 42 concurrently has
passed the sensor array 21. This coin size category includes the 10
cent piece.
The output leads 74, 88, 90 and 92 from the gates 48, 50, 52, 54
respectively lead to a gate 94 which produces a high output signal
when the signal on any one of its inputs, leads 74, 88, 90 or 92 is
low. The output signal from the gate 94 is directed through a
differentiator 95 and an OR gate 96 to the flip-flop 58. The
flip-flop 58 is reset as soon as a high output signal from gate 94
indicates it has become disabled by the completion of a coin size
categorization signal. As was mentioned above the flip-flop 58 is
also reset by a signal from the coin arrival sensor 30 indicating
that a coin has entered the device.
The output signal from the gate 94 is also directed to the coin
acceptance ratio examination phase of the combinatorial circuit 47
as described below. In addition to the leads 74, 88, 90 and 92
leading to the gate 94 corresponding individual leads 74', 88', 90'
and 92' are also provided to make available individual signals
indicating the size category of the coin passing through the coin
selector device. When a coin does not obscure sensor 46, either
because it is too small or it does not reach the sensor 46, no
signal occurs on any of the leads 74', 88', 90' and 92'. This
completes the discussion of size category determination.
Coin Velocity and Chordal Length Examination Circuit
FIG. 3 also illustrates the remainder of the logic system which
completes the combinatorial circuit 47 allowing comparison of the
signals generated by the various sensors which form the coin
property sensing array 21 with predetermined signals to determine
whether or not an acceptable coin has passed through the system.
Four flip-flops 102, 104, 106 and 108 are provided representing the
acceptable coins, in this case a 50, 25, 5 and 10 cent piece,
respectively. An enabling lead from the corresponding coincidence
gates 48, 50, 54, 52 is fed into each of the flip-flops 102, 104,
106 and 108, so that a low signal on any one of the gate output
leads 74', 88', 90' and 92' partially enables one of the flip-flops
102, 104, 106 and 108. Since only one of these output leads can
have a low signal at any one time, the remaining three flip-flops
are disabled.
Each of the flip-flops, 102, 104, 106 and 108 are connected to a
decoder 110 which is fed by a counter 112. A timing oscillator or
clock 114 is gated to the counter 112 along lead 115 by a
coincidence gate 116 which directs a desired signal to the counter
112 only when all of its inputs are high. The other inputs to the
gate 116 are the output lead from the gate 94, a lead 117 from the
"set" output of the flip-flop 58 indicating that a proper size coin
is in front of the coin sensor array 21, and a lead 118 from the
decoder 110. The decoder lead 118 represents a high count stop so
that once the counter gets beyond the highest count that an
acceptable coin will have, the signal on lead 118 automatically
disables gate 116 to prevent recycling of the counter.
The timing oscillator signal is converted by a circuit 119 into
positive pulses referred to as A-clock pulses and negative pulses
referred to as B-clock pulses, the pulses being out of phase with
one another. The positive pulses are fed to the counter 112 and the
negative pulses are directed to the decoder 110 in order to trigger
the decoder to read the counter 112 intermediate the transitions
between high and low state of the positive pulses.
For a four coin set as described in this embodiment, the decoder
provides a series of four sets of output signals, each set
consisting of a low and high count for each particular coin. Each
of these sets of decoder output signals are directed to the
corresponding one of the flip-flops 102, 104, 106 and 108, the low
count signal being an enabling signal and the high count signal
being a disabling signal. The fourth enabling signal to each
flip-flop is a signal on the common lead 120 from the output of the
coincidence gate 116 so that the flip-flop cannot be enabled unless
the gate 116 has all four inputs as desired, in this case high.
This prevents setting of these flip-flops if the counter or decoder
is erroneously triggered by stray signals.
When a coin which fits within a size category corresponding to
either 10, 5, 25 or 50 cent pieces, passes through the coin
selector 10 the gate 116 is enabled and the positive pulses are fed
to the counter 112. The number of pulses fed to the counter 112,
and hence to the decoder 110, are related to the size of the coin
and are inversely proportional to the velocity of the coin that is
passing through the system. As soon as the gate 48, 50, 52 or 54
which enabled the gate 94 becomes disabled, the gate 116 becomes
disabled and the counter stops receiving pulses.
Looking at the sensor signal sequence table in FIG. 4, there is
illustrated the time during which the flip-flops 102, 104, 106 and
108 are enabled for acceptable coins. If the counts received by the
decoder during the interval represented by the set and reset dotted
lines in the sequence table is equal to the prescribed acceptable
number for an acceptable coin represented by the flip-flop enabled
by the coin size determination, that flip-flop remains set. The set
flip-flop provides a signal indicating that a coin of acceptable
chordal dimension and velocity has passed through the system and
indicates the denomination of that coin. Since the counts are
representative of the size and velocity of the coin and, for the
reasons described above, since the velocity of an electrically
conductive, non-ferromagnetic coin after it is exposed to the
magnet 18 is related to the coin's acceptance ratio, this
examination of coin size and coin velocity provides an accurate
means for determining the authenticity and denomination of a moving
coin.
Because only one of the flip-flops 102, 104, 106, 108 can be set at
any one time, there is no ambiguity.
A signal from the enabled flip-flop is then fed to a coin
acceptance means 122 which energized the coin acceptance solenoid
(not shown) to remove the coin acceptance gate 22 from the path of
the coin and allow the coin to drop into the coin acceptance
passageway 23. If none of the flip flops 102, 104, 106, 108 are
enabled by the time the coin reaches the coin acceptance gate 22,
the coin will hit the gate and be directed into the coin rejection
passageway 24.
In addition to the enabled flip-flop transmitting a signal to the
coin acceptor 122, a signal also is transmitted to a conventional
pulse maker 124 which in turn sends a weighted signal to a
conventional binary accumulator 126. The weighted signal is
representative of the particular flip-flop that is enabled. For
example, the pulsemaker 124 will transmit a single pulse is the 5
cent flip-flop 108 is enabled, a double pulse if the 10 cent
flip-flop 106 is enabled, five pulses if the 25 cent flip-flop 104
is enabled and ten pulses if the 50 cent flip-flop 102 is enabled.
Alternatively, for a 50 cent whose weighted value is ten times that
of the 5 cent the pulsemaker could gate five pulses into the second
stage of the binary accumulator 126. The accumulator is
conventionally gated to the coin operated device 128 so that the
device may vend at certain predetermined accumulated values.
A pulsemaker disabling coincidence gate 130 is provided having a
pair of inputs, one input coming from the accumulator and
representing a high price disable and the second input coming from
the last of the sensors 42 in the array 21. A high price disabler
lead 132 disables the pulsemaker 124 when the accumulator has
registered a predetermined maximum value, such as the price of the
highest priced item in the coin operated device. A similar high
price disabler lead 134 is directed to a coincidence gate 136 to
prevent acceptance of any coins after the accumulator has
registered the predetermined maximum value. If any additional coins
are inserted into the coin sensing device after the accumulator has
reached its maximum value, the coins will be rejected and returned
to the depositor.
The signal from the sensor 42 is provided to the pulsemaker 124 in
order to disable the pulsemaker until the coin has cleared the
sensor 42 so that it is certain that the counter has completed
registration of an appropriate count for the coin before the
pulsemaker examines each of the flip-flops 102, 104, 106, 108. This
will preclude the pulsemaker from recognizing a signal from one of
the flip-flops during an interim period while the counter is still
recording coin velocity.
While the above discussion pertains to a coin sensing array 21
having a single primary sensor 42 and a series of two secondary
sensors 44, 46 it is clear that the disclosed embodiment can be
modified to use a single secondary sensor or a number greater than
two can be used. Each secondary sensor provides the capability of
accurately evaluating at least two different but similar size
coins. While each secondary sensor together with the primary sensor
42 is capable of examining more than a pair of coins, for maximum
accuracy it is preferred that the secondary sensor be located with
respect to the primary sensor such that the time duration during
which the velocity check of the coin is being made is minimal. For
example, turning to FIG. 2, secondary sensor 24 together with
primary sensor 42 could be used to examine the velocity properties
of all coins larger than the spacing between these two sensors,
namely the 5, 25 and 50 cent pieces. However, the time duration of
a velocity check for the 25 and 50 cent pieces would be undesirably
large and render the coin sensing system less acurate. The acuracy
of the system is increased greatly by the addition of one more
sensor 44 which provides the ability to more closely examine the
coin acceptance ratio of the two larger coins and also the chordal
dimension of the two larger coins. It should also be noted that
while the description above and the accompanying drawings assume
location of the series of secondary sensors ahead, with respect to
coin travel, of the primary sensor 42, the orientation of these
sensors could be reversed with an accompanying modification of the
logic circuitry. Finally, it should be noted that the coin sensing
array described herein is useful not only in the disclosed
embodiment for conductive, non-ferromagnetic coins, but also in any
other coin or token discriminator in which the velocity of a moving
coin or token is dependent in some way upon factors associated with
the denomination and authenticity of the coin.
* * * * *