JPH0550792B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention is used in coin handling machines, especially coin sorting machines and coin depositing machines having forced conveyance means, to identify the denomination and authenticity of coins. The present invention relates to a material sensor suitable for.

(Prior art and its problems) There are various types of coin sorting machines (including coin depositing machines and coin depositing and dispensing machines). For example, coins of mixed denominations are sent out one by one from a coin reservoir called a hopper to an inclined passageway, and the coins roll down the inclined passageway due to their own weight, and after passing through a discrimination section consisting of an optical sensor and a material sensor, the discrimination results are obtained. Depending on the denomination, there is a type that is stored in a gold box of the corresponding denomination. In this type of device, when the coin rolls, the coin may jump due to dirt etc. adhering to the inclined passage surface, and if the coin jumps in the discrimination section, the output level of the material sensor changes. However, there was a drawback that the material could not be determined accurately. Another disadvantage of this type of coin sorting machine is that it has a slow processing speed (approximately 600 coins per minute).

On the other hand, coins of mixed denominations are placed on a horizontal rotary disk, and the coins are sent out by centrifugal force.The coins are moved on a passageway by a forced conveyance means such as a belt, and are sorted by a sorting section to be classified into the corresponding denomination. The type of coin sorting machine that stores coins in a gold box has a faster processing speed than the above-mentioned coin sorting machine because the coins are forcibly transported. However, when coins move on the passage, coins of small denominations, such as 1 yen coins and 5 yen coins, are not necessarily restricted to one end of the passage. This occurs due to factors such as smaller diameter coins being pushed by larger diameter coins when coins of various denominations are fed out from the horizontal rotary disk. Therefore, even if a material sensor is attached to this type of coin sorting machine to detect mixed fake coins (including foreign coins), the positional relationship of the moving coins with respect to the material sensor cannot be fixed. The output level of the coins fluctuated even for one denomination of coins, making it impossible to detect mixed counterfeit coins. However, for those with multiple sorting holes in the downstream stage so that the ones with the smallest diameter fall down the passage in order according to the denomination, a regulating member is installed just before the sorting hole, so each denomination can be separated. It is not impossible to detect counterfeit coins by installing individual material sensors in front of the sorting hole. However, providing individual material sensors increases the cost considerably, so it is not preferable in practice.

(Objective of the Invention) The present invention has been made in view of the above-mentioned circumstances.When an object such as a coin is conveyed on a passage, the output level does not fluctuate even if it moves in a direction perpendicular to the direction of conveyance. It is an object of the present invention to provide a material sensor that can reliably obtain an output corresponding to the material mass of an object.

(Means for Solving the Problem) The configuration of the present invention will be explained using FIG. 1 and FIG. 2. The material sensor 100 is entirely molded and integrated with resin or the like, and has a central portion 101 and an upper central portion 10 through which the object to be detected passes.
2 are open. The primary core 103 at the bottom has a primary coil 104 and a secondary coil 1 for excitation.
05 is wound, and secondary cores 106 and 107 are arranged on the upper part, which are separated left and right at the center 102, and secondary coils 108 and 109 are wound around these secondary cores 106 and 107, respectively. ing. The shape of the vertical cross section of the secondary cores 106 and 107 is such that the distance between each lower surface and the upper surface of the primary core 103 increases outward from the open portion of the upper center 102. Figure 2 shows primary cores 103 and 2.
It shows the positional relationship between the secondary cores 106 and 107, and when the primary core 103 is excited by the primary coil 104, magnetic flux lines 110 extending toward the secondary cores 106 and 107 are generated. .

(Operation of the invention) Figure 3A shows the magnetic flux lines 110 when there is no secondary core.
You can see that it is curved and extending outward. Then, above the primary core 103, 1
It was confirmed that when two rectangular parallelepiped secondary cores 106A and 107A separated from the secondary core 103 were arranged, the magnetic flux lines 110 were directed inward as shown in FIG. 3B. However, secondary cores 106A and 1
If the shape of 07A is like this, the magnetic flux lines 110 are not uniformly oriented as shown in the figure, so the sum of the coil differential outputs for detection, which will be described later, passes through the central part 101. It changes due to the left and right shift of the object. Therefore, if the bottom surfaces of the secondary cores 106 and 107 are sloped as shown in FIG. The outward slope of the magnetic flux lines 110 at the secondary cores 106 and 107 further decreases
The magnetic flux densities are also almost equal at the bottom of the plane.

The operation of this invention will be explained using FIGS. 4A and 4B. As shown in FIG. 4A, x=0 when the coin 120 as the object to be detected passes the leftmost part of the center part 101 of the sensor 100, and the coin 120
The coil output MS when is shifted to the right is shown in Figure B. In FIG. 4B, A indicates the differential output between the secondary coils 105 and 108 in FIG. 1, and B indicates the differential output between the secondary coils 105 and 109, respectively. In this invention, the material of the object is detected by adding these differential outputs A and B. However, if the secondary core has a structure as shown in FIG. However, by adding an inclination as shown in FIG. 3C, it becomes a constant straight line as shown in characteristic C. Therefore, even if the coin 120 shifts from side to side, the material of the object can always be accurately detected.

(Embodiment of the invention) A material sensor 100 that operates on the principle described above is
An example of application to a coin sorting machine is shown in Fig. 5.

Reference numeral 401 denotes a rotating disk, in which mixed denomination coins 420 are moved along the surrounding wall 402 due to the centrifugal force caused by rotation, and two or more coins are prevented from stacking on top of each other by a thickness regulating member (not shown). ,
The sheets are sent out one by one from the outlet 403 to the passage 404. The coin 420 sent out is pulled by the pulley 405
And by the round belt 407 stretched on 406,
It is forcibly conveyed on the passage 404 in the N direction in the figure. Since the speed of the round belt 407 is set faster than the speed at which the coins 420 are sent out from the rotating disk 401, the continuous coins 420 are separated and conveyed. The coin 420 passes over the sensor 200 (described later) installed in the passage 404, and further passes through the center portion 101 of the material sensor 100. The material of the coin 420 is determined by the outputs of these two sensors.
The diameter and presence or absence of holes are determined. If the coin is determined to be a counterfeit coin or an abnormal coin, when the sensor 410 detects the coin, the elongated hole 411 provided at the bottom of the passage
A branching plate (not shown) protrudes from the counter by driving a solenoid or the like, and these counterfeit coins are sorted toward the right in FIG. 5, pass through a guide 412, and are stored in a storage section (not shown) provided below. . The sensor 410 and the branch plate are paired, and a plurality of pairs are provided in the downstream of the passage 404 corresponding to each denomination. When the coin 420 reaches the corresponding sorting location, the corresponding branch plate protrudes onto the passage 404, so that the coin is reliably stored in the storage section for each denomination. In addition, in the event that the coin 420 becomes jammed in the sorting section, etc., the pulley 40
The pulley 405 side can be rotated upwards using the shaft 6 as a fulcrum, and the round belt 407 can be moved upwards through the opening 102 at the top center of the material sensor 100, making it easy to remove stuck coins. be able to.

FIG. 6 shows a block diagram of the control system. First, the basic processing of the output of the material sensor 100 will be explained.

The outputs of the secondary coils 108 and 109 and the secondary coil 105 of the primary core 103 are connected to an amplifier 50, respectively.
1,511,521, half wave rectifier 502,51
2,522 and low pass filters 503, 51
3,523 to the addition/subtraction circuit 542, and the difference output A between the secondary coils 105 and 108;
The difference output B between the secondary coils 105 and 109 is calculated, and the sum value C of the difference outputs A and B is determined. Then, this added value C is sent to the A/D converter 543.
The signal is converted into a digital signal at a predetermined timing, and this signal is sequentially stored in the RAM 541 via the CPU 500. At this time, the previously stored value and the current value are compared, and if the current value is larger, this value is stored as the maximum value. Coin 420 is material sensor 1
As the value approaches 00, the sum C of the differential outputs increases as shown in FIG. 7, and conversely decreases when the center of the coin 420 passes beyond the center CL of the material sensor 100. The peak of the signal is the maximum value
Since it is stored in the RAM 541, it is read out and the authenticity and denomination of the coin are determined based on whether or not it falls within the range of reference values for each denomination previously stored in the ROM 540. FIG. 8 shows a comparison of the levels of the addition signal C for various coins.
The level of signal C decreases in the order of yen coins, 10 yen coins, 5 yen coins, 500 yen coins, 100 yen coins, and 50 yen coins, and the difference between 500 yen coins and South Korean 500 won becomes extremely small. However, the material can be reliably identified. In addition, the secondary cores 106 and 1
The shape of the slope 07 is finally determined experimentally so that the sum C of the differential outputs is constant. In this case, it is desirable to determine the inclination angle by using a trajectory that keeps the magnetic flux density constant as a rough guide.

In the material sensor described above, the material sensor 10
When the temperature T of the 0 environment changes, the coil impedance changes, the current flowing through the secondary coils 105, 108, and 109 changes, and the differential outputs A and B also change, so more accurate discrimination can be performed. In this case, the output C or ROM540 corresponds to the temperature T.
It is necessary to correct the reference value within. An example of this will be explained below.

By the way, the temperature T is determined by the material sensor 1 of the coin 420.
It can be detected by the output level of the secondary coil 105 when it is not near 00. To detect the absence of coins, for example, the output C of the adder/subtractor circuit 542 and the output of the secondary coil 105 are sampled alternately, and if the sum value C of the differential outputs does not change for a predetermined time (a predetermined number of times), and When the value is at the level when there is no coin nearby, it is determined that there is no coin, and the value of the secondary coil 105 read at this time is stored in advance in the ROM 540 for each temperature (for example, 1°C pitch). By comparing the temperature T
can be detected. After the maximum value of the sum C of the differential outputs (Fig. 7) is determined based on this temperature information, this maximum value is corrected and compared with a reference value in a predetermined range to determine authenticity and denomination. . Alternatively, the reference value for each denomination in a predetermined range may be corrected based on the above temperature information, and then the judgment may be made by comparing it with the maximum value of the sum of the differential outputs. You can calculate it each time based on the
Write the correction value for each temperature in advance to ROM540,
The correction value may be extracted directly from the address corresponding to the detected temperature. Further, the temperature detection timing may be immediately after turning on the power, immediately after a start command is given, or when the flow of coins stops during coin processing.

Next, FIG. 9 shows the configuration of a hole detection sensor 200. This sensor 200 is a known differential magnetic sensor, and when a coin 420 passes, a difference occurs between the outputs of the upper secondary coil 202 and the lower secondary coil 203, and this difference DS is taken out as an output. its output
As shown in FIG. 6, the DS is input to an A/D converter 543 via an amplifier 531, a half-wave rectifier 532, and a low-pass filter 533, and is converted into a digital quantity. Figure 10A shows an example of the output DS for a 5 yen coin with a hole, Figure 11 shows an example of the output DS for a 1 yen coin without a hole, and Figure B shows the respective differential outputs.
Figure C shows the ternary output.

The hole detection operation of the sensor 200 for the coin 420 will be explained according to the flow shown in FIG.

The output DS of the sensor 200 is the A/D converter 543
However, according to the channel switching signal from the CPU 500, the sum C of the differential output, the output of the secondary coil 105, and the output of the sensor 200 DS = f(t)
are repeatedly written to the RAM 541 as sampling values (step S1). The number of samplings is approximately several hundred times per sheet. Assuming that the sampling period is α, each time the output DS of the sensor 200 is read, f'(t) = f, which approximately corresponds to the differential coefficient.
(t-α)-f(t) is also calculated and stored, and f
Based on the value of (t), it is determined that the coin 420 has passed over the sensor 200 (step S2). Then, the maximum value Max{f'(t)} and the minimum value Min{f'(t)} are detected among the stored differential coefficients f'(t) (step S3), and from these two values differential coefficient
Threshold S ₊ for pulsing f′(t)
and S _- are calculated (step S4). The threshold on the positive side is S ₊ =K1×Max×{f′(t)}, and the threshold on the negative side is S ₋ =K1×Min×{f′(t)}.
K1 is a constant and can be set arbitrarily in the design, but for example
Set it to 0.2. This is to deal with fluctuations in output level. As a result, the individual values of the differential coefficient f'(t) stored in the RAM 541 are compared with the thresholds S ₊ and S _- and pulsed into three values (step S5). That is, “1” if f′(t)≧S ₊ , “0” if _S− <f′(t)<S ₊ , f′(t)≦
S _-
If so, "-1" is newly stored in the RAM 541.
Then, the maximum width part is the part marked “+1”.
t1 and the maximum width part t2 at the point where it is “-1”
(distinguished by the number of consecutive addresses that are +1 (or -1)) (step
S6), and the time t1′ when those values are multiplied by the constant K2.
t2' is calculated (step S7). time width t1′ and
The reason why t2' is not fixed is to be able to respond to changes in the conveyance speed. Read the data from the address of RAM541 corresponding to time t1' portion, determine whether there is "-1", and then
Read the data from the address of RAM541 corresponding to the t2′ part, determine whether there is “+1”, and read “-
1, +1” hits the corresponding area, it is determined that the coin with the hole has passed (step
S8). Further, if there is no corresponding pulse at times t1' and t2', and there is no pulse (+1, -1) at a location other than times t1' and t2', the coin is determined to be a coin without holes (step S9). Furthermore, there is no corresponding pulse at times t1' and t2', but when a pulse occurs at a location other than time t1' and t2' (for example, -
If there is +1 instead of 1), it is determined that the coin is deformed and has been bent. The signal DS that is determined to be such a deformed coin is, for example, as shown in Figure 13A, and its differential waveform is as shown in Figure 13B,
The three-value output is shown in Figure C.

Next, an example will be described in which the diameter of a coin is determined based on the output values of both the sensor 200 and the material sensor 100.

Figure 14 shows a coin 420 and each sensor 100, 20.
0 positional relationship is shown. When the coin 420 without a hole is conveyed in the direction of the arrow, the output of the sensor 200 becomes the 15th coin.
The output C of the sensor 100 is as shown in Figure A, and the output C of the sensor 100 is as shown in Figure B. First, the output DS of the sensor 200 =
f(t) rises, and then when the coin 420 reaches the position of the sensor 100, C=g(t) rises.

The diameter determination operation will be explained based on the flowchart of FIG. As mentioned above, sampling
Sum C of differential output of sensor 100, secondary coil 10
5 and the output DS of the sensor 200 are repeated in this order (step S10). sensor 200
The sampling value of the output DS=f(t) and the sum value C=g(t) of the differential output of the sensor 100 is stored, and at the same time, it is compared with the previous value, and if the current value is large, the maximum value is When g(t) falls below a predetermined level after increasing, that is, coin 4
20 has almost completely passed through the subsequent material sensor 100, the maximum value of sampled g(t)
Max{g(t)} is read out (steps S11, 12),
g(t) = t value that satisfies Max {g(t)}×0.4
The address of RAM 541 corresponding to t' is detected (step S13). In other words, the time point t' at which the sum C of the differential outputs reaches 40% of the peak value is searched. peak value 4
There are two parts that correspond to the time, but the one with the earliest time is used. Here, the coefficient 0.4 can be appropriately set depending on the distance between the sensors, the size of the sensor 200, etc., which will be described later. Using the address of g(t'), f(t') is read from the address where the value f'(t') of f(t) at the same time t' is stored. Also f
The maximum value Max{f(t)} of (t) is also read out (step S14), and Pr=f(t')/Max{f(t)} is calculated (step S15). In other words, what percentage of the peak of the sensor 100 corresponds to the output DS of the front-stage sensor 200 at the time when the sum C of the differential outputs of the rear-stage sensor 100 reaches 40% of the peak is calculated. be. If the value of the ratio Pr is large, it means that the proportion of the coin 420 touching the sensor 200 is large. Read out the standard value range for each denomination stored in the ROM540 in advance and set the ratio Pr.
It is determined whether or not the coin falls within the range, and if it falls within any range, the denomination is specified, and if it does not fall within either range, it is determined to be a counterfeit coin (step S16).

Note that an example of the reference value range of the ratio Pr is shown in FIG. Here, the size of Pr and the diameter are reversed for 1 yen and 50 yen, but this is because the aluminum of the 1 yen coin has stronger magnetism than the cupronickel of the 50 yen coin, and has a greater effect on the sensor. For the same material, Pr and the size of the diameter can be set in a proportional relationship. In the above, when g(t)/Max{g(t)} is 0.4,
For example, let this ratio be Cr, and Cr and Pr
You may also seek a relationship with

Although the material, the presence or absence of holes, and the determination of diameter have been explained separately, sampling is common. By taking these three discrimination conditions into account, more reliable coin identification can be achieved. Note that even if a coin jumps in the vertical direction of the sensors 100, 200, there will be no malfunction because the detection is performed by differential action between the two coils.

(Effects of the Invention) In this invention, since the shape of the core is devised, the output is stable even when the coin is displaced in a direction perpendicular to the transport direction, and the material of the coin etc. can be reliably identified.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the structure of the material sensor of the present invention, FIG. 2 is an exploded view thereof, FIGS. 3A to C are diagrams for explaining the shape of the core used in the sensor of the present invention, and FIG. 4 A and B are diagrams for explaining the detection principle of this invention, FIG. 5 is a block diagram showing an example of applying the sensor of this invention to a coin sorting machine, and FIG. 6 is a block diagram showing its control system. Figures 7 and 8 are diagrams for explaining its operation, Figure 9 is a structural diagram of the sensor for identifying the coin denomination, etc., and Figure 10 is a diagram for explaining the operation.
Figures A to C, Figures 11A to C, and Figures 13A to C are diagrams for explaining the operation, Figure 12 is a flowchart showing an example of the operation, and Figure 14 shows the positional relationship of the two sensors. 15A and 15B are timing charts for explaining the operation, FIG. 16 is a flowchart for explaining an example of the operation, and FIG. 17 is a diagram for explaining coin identification. 100...Material sensor, 103...Primary core,
106, 107... Secondary core, 105, 108,
109...Secondary coil, 200...Sensor, 42
0...coin, 500...CPU, 540...
ROM, 541...RAM, 542...addition/subtraction circuit, 543...A/D converter.

Claims (1)

[Claims] 1. A wide primary core, a primary coil wound around the primary core and excited, and a first secondary coil wound around the primary core and electromagnetically induced by the primary coil. a coil, and two pieces, each of which is provided facing the primary core by cutting its central portion, and configured such that the distance between the lower surface and the upper surface of the primary core increases from the central portion toward both ends. and a second core wound around each of these secondary cores.
and a secondary coil, and the material of an object passing between the primary core and the secondary core is detected by the outputs of the first secondary coil and the second secondary coil. Characteristic material sensor.