JPH048891B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Industrial Field of Application) The present invention relates to a sensing plate device for an automatic door that also serves as an electrical device.

(Prior technology) High-frequency oscillation type proximity switches used in automatic doors of buildings, etc. have a sensing plate made of two conductive plates embedded in the mat part, and oscillate a high frequency of 1 to 20MHz in the oscillation part. The sensing plate is used as part of the oscillation circuit. When the human body approaches the mat, the frequency of the oscillation circuit changes due to stray capacitance and resistance loss between the human body and the sensing plate, and the output level changes as the sharpness Q changes. The change is taken out to the outside and operates the switch part,
This controls the opening and closing of the automatic door.

Figures 3A and 3B show the structure and embedding of a conventional sensing plate device, and show two sensing plates 1 and 2.
A resin frame 3 is sandwiched between them, and a printed circuit board circuit (oscillation circuit) 4 with electronic elements such as transistors mounted thereon is disposed, and lead wires 5 and 6 from the printed circuit board 4 are connected to sensing terminals, respectively. It is connected to plates 1 and 2 by soldering or the like. and,
After making predetermined adjustments, it is fixed with a mold 7 and is buried under the floor near the entrance of the automatic door. Power is supplied to the printed circuit board circuit 4 via the transmission line 8, and the detection signals detected by the sensing plates 1 and 2 are transmitted to a switch circuit separately installed in the automatic door drive section, and this opening/closing signal is It is designed to control the opening and closing of the door.

Now, to explain the principle of such a sensing plate device, first, FIG. 4 shows sensing plates 1 and 2 without a feeder.
This is an example of using the oscillator as part of an oscillator, and shows part of the Hartley type LC oscillator. The oscillation condition for this oscillator is that the feedback reactance is capacitive C _c
Therefore, the condition is that Z ₁ and Z ₂ are inductive reactances. The reactance curves of the inductive reactances Z ₁ and Z ₂ are shown in FIG. In FIG. 5, the solid line shows the characteristics of the base side of transistor Q ₁ , and the broken line shows the characteristics of transistor Q ₁
As shown in FIG. 6, the case where the resonant frequency shifts to f ₀₁ ' due to the addition of capacitance C _b when the hand approaches the sensing plate 1 is shown by the dashed line. And now, as shown in Figure 5, f ₀₁
If the adjustment is made so that <f ₀₂ , this condition is satisfied in the area shown by diagonal lines. However, it is well known that the actual oscillation frequency is near the frequency f ₀₁ where the reactance is large.

Here, in FIG. 4, the tuning circuit provided on the base side of the transistor Q ₁ has a fixed capacitance C 2 and a coil, with the capacitance of the sensing plates 1 and ₂ being C ₁ .
At L ₁ The tuning circuit on the collector side is the adjustment capacitor C ₃
and in coil L ₂ becomes. Then, according to equation (2), the oscillation output is adjusted to the maximum by adjusting the variable capacitor _C3 so as to meet the conditions shown in FIG. In such a state, when a hand or the like is brought close to the sensing plates 1 and 2 as shown in Figure 6, the capacitance on the ground side (sensing plate 2) is C _a between it and the human body, and the capacitance between the ground side (sensing plate 2) and the sensing plate 1 is There is a capacitance C _b between sensing plates 1 and 2, and the capacitance C ₁ between sensing plates 1 and 2 is (1/(1/C _a +1/
C _b )) increases. Here, the capacitance C _a has a large opposing area between the human body, etc. and the ground, so C _b ≪C _a
Therefore, it can be assumed that almost C _b is added.
As a result, the sensing plate capacitance (C ₁ + C _b ) is obtained, and the tuning frequency decreases by this amount according to equation (1), and the resonant frequency
Since f ₀₁ and f ₀₂ are detuned, the oscillation output decreases. The automatic door is switched by detecting this change. This is the basic principle of automatic doors, and even if the oscillation circuit is changed, the operation shown in FIG. 6 will not change. In addition to the capacitance, a loss resistance R is also added, which acts to reduce the sharpness Q of the circuit, and in this case as well, the oscillation output is reduced and the detection signal can be large.

In this case, the fact that the sensing plates 1 and 2 as shown in FIG. Aerial line・
"Transmission Circuit", page 70. That is, the sensing plates 1 and 2 act as a type of capacitor if the supply line is ignored, as shown in Figure 7A, but if one of the capacitors is opened, Then, when the supply line is arranged as shown in Fig. 7B, since the sensing plate 2 and the supply line are at the same potential, a part of the high-frequency current begins to radiate. Eventually, the state will be as shown in Figure C, and the dipole antenna will be in the state shown in Figure 8.If the sensing plate 2 is incompletely grounded, the sensing plate 1
Radio waves are radiated between the source and the supply line, and maximum radiation occurs when the length of the supply line becomes, for example, λ/4 of the wavelength λ.

Here, conventional oscillation circuits and switch circuits (for example, Japanese Patent Publication No. 62-8048, Japanese Patent Publication No. 62-8049)
A specific example of this is shown in FIG. 9A, in which two sensing plates 10 and 11 are used as part of the oscillation element, and the sensing plates 10 and 11 are A high frequency oscillation circuit 12 disposed between 10 and 11, a loading coil L2 and a resistor R4 interposed between the sensing plate 10 and the input part of the high frequency oscillation circuit 12, and the output level of the high frequency oscillation circuit 12. A switch circuit 13 connected to the high frequency oscillation circuit 12 and the high frequency oscillation circuit 12 and the switch circuit 13 for detecting and controlling the opening and closing of the door.
Chiyoke coil L3, which is inserted into the power supply lines 14, 15 and the signal line 16, respectively, which are connected between
It includes L4 and L5.

As mentioned above, the sensing plate 10 originally functions as a capacitor, and since the loading coil L2 and the resistor R4 are inserted into the input section of the oscillation circuit 12, the oscillation frequency of the oscillation circuit 12 is dependent on the inductance L4. Capacity Ca Ca=C ₆ +C ₂・C ₃ /C ₂ +C ₃ ...(3) On the sensing plates 10 and 11 side, loading coil L2, stray capacitance C _c , and debinding capacitor
Since it is only necessary to make C ₃ resonate, adjustment is extremely easy. That is, the equivalent circuit of the resonance system of the oscillation circuit 12 and sensing plates 10 and 11 in FIG. 9A is shown in FIG. 9B, and the resonance frequency ₀₁ on the oscillation circuit 12 side is Therefore, the resonance frequency ₀₂ on the sensing plates 10 and 11 side is Therefore, it turns out that it is sufficient to set ₀₁ ≒ ₀₂ .

Note that the sharpness Q of resistor R4 decreases when an object that is not a pure conductor, such as a human, approaches, but when a conductor such as a metal approaches, the resistance becomes almost 0, so only the frequency changes. This is to prevent the output level from becoming high due to changes in the output level. Therefore, the resistor R4 may be connected in series or in parallel with the loading coil _L2 .

In this way, when manufacturing the oscillation circuit 12, the above (3)
A highly sensitive automatic door switch can be obtained by determining the capacitance Ca from the relationship of the equation and adjusting the inductance of the loading coil L2, that is, the number of turns of the core, from the sensing plate capacitance C _c . Further, when the oscillation circuit is buried underground, stray capacitance C _c and leak resistance R _c are added, but these effects are removed by the divide capacitors C2 and C3. In other words,
The oscillation frequency of the oscillation circuit 12 is determined by the capacitance Ca and the inductance L1, and by adjusting the inductance of the loading coil L2 according to the size of the stray capacitance C _c to bring it closer to the oscillation frequency, a switch with good sensitivity can be obtained. .

On the other hand, power is supplied to the oscillation circuit 12 via power lines 14 and 15 and the switch coils L3 and L4, and signals are supplied from the oscillation circuit 12 to the switch circuit 13 via the signal line 16 and the switch coil L5. In addition, these chiyoke coils L3 to L5
plays the role of completely preventing high frequency leakage to the power supply section. Therefore, the switch circuit 13 is an automatic reset type amplifier (for example, Japanese Patent Publication No. 56-22170).
and a comparator section, and the automatic reset type amplification section has a level signal input from the oscillation circuit 12 to the non-inverting input terminal of the DC amplification section 131, and a capacitor C8 to the inverting input terminal via the resistor R5. is connected, and the output V ₀ of the DC amplifier 131 is input to one side of the comparator 132, and
Diode D is connected to the inverting input terminal via resistor R6.
2 to the connection point between the capacitor C8 and the resistor R5. Further, the voltage from the variable resistor R7 is given to the other side of the comparator 132 as a reference, and the voltage from the variable resistor R7 is applied to the other side of the comparator 132.
The output of 32 is inputted to the base of transistor Q2 via resistor R8, and the excitation winding RY of the relay is connected to the collector of transistor Q2 together with a diode D3 for surge absorption. _Therefore , the output _V0 of the DC amplifier 131 is as follows _, where the non-inverting input is _V1 , the inverting input _{is V2} , and the amplification factor _{is A1} . . However, if we consider the case where the charge on capacitor C8 is 0, the inverting input is -V, so the output
V ₀ becomes V ₀ = (V ₁ −V) A ₁ ...(7). In other words, the output V ₀ is saturated at +V, and the output V ₀ begins to charge the capacitor C8 through the diode D2, and when it reaches V ₁ ≒ V ₂ , the output
V ₀ becomes almost V ₁ and is no longer charged through diode D2. If there is a discharge due to the leakage current of the capacitor C8, this appears as a difference between V ₁ -V ₂ and the output V ₀ becomes (V ₁ -V ₂ )A ₁ , so it is immediately charged through the diode D2. As this process is repeated, the output V ₀ becomes almost the voltage of the non-inverting input V ₁ and stabilizes. In this state the voltage
When V ₁ is changed by -ΔV ₁ , the difference between the inverting input and the non-inverting input becomes -ΔV ₁ since V ₁ = V ₂ , and the output V ₀ is V ₀ = -ΔV ₁ A ₁ ...( 8) becomes. Similarly, if the voltage V ₁ is changed by +ΔV ₁ , the output V ₀ becomes V ₀ = +ΔV ₁ A ₁ ...(9), but the capacitor C is connected through the diode D2.
8, the output V ₀ is the non-inverting input V ₁
It becomes stable when it becomes equal to +ΔV ₁ . That is, when the non-inverting input changes in the positive direction, this DC amplifier 13
An output of 1 has an amplification factor of 1, and only in the case of a negative change, the amplification factor becomes A ₁ . Then, when changing in the negative direction,
The voltage charged in the capacitor C8 is gradually discharged due to the leakage voltage of the capacitor and the input impedance of the DC amplifier 131, and when it drops by ΔV ₁ , the difference between the inverting input and the non-inverting input becomes 0, and the output becomes It becomes stable at V ₁ −ΔV ₁ . In other words, since ΔV ₁ is a minute value, it can be considered that the state has almost returned to the state at the time of change, and the time period in between can be set appropriately.

Here, the output of the DC amplifier 131 is V ₁
So, if the signal from the oscillation circuit 12 drops by ΔV ₁ , the output will be −ΔV ₁ A ₁ as described above.
This is input to one side of the comparator 132. Thus, the reference voltage V3 is input from the variable resistor R7 to the other side, and it is set as follows: V ₁ >V ₃ >ΔV ₁ (10) ΔV ₁ A ₁ >V ₃ (11). In this way, when the change occurs, V ₁
>V ₃ , so the output of comparator 132 becomes negative, and after the change, V ₃ <ΔV ₁ A ₁ , so the input difference is reversed, the output becomes positive, transistor Q2 turns on, and relay winding RY is energized and the door is opened via this relay contact. However,
If this state is maintained, the voltage across the capacitor C8 gradually decreases, and when it drops to ΔV ₁ , the output of the DC amplifier 131 becomes V ₁ -ΔV ₁ . In this state, the input to the next stage comparator 132 is
Since V ₃ > ΔV ₁ , the input is inverted again and V ₁
>V ₃ and its output becomes negative, turning off transistor Q2 and cutting off the excitation, thereby closing the door.

(Problem to be Solved by the Invention) However, in the conventional sensing plate device as described above, electrical equipment such as road heating and shoe mud remover is wired to the entrance/exit of the automatic door (on the floor of the sensing plate). The drawback is that it will not function properly as an automatic door switch if left in place. In normal use, the sensing plate acts as a capacitor, but as shown in FIG.
When the load heating conductor (wiring) 22 is disposed above, the radio waves output from the sensing plate 21 are absorbed by the conductor 22 as explained in FIGS. 7A to 7C, and the power supply line 23 is This is because it is radiated as an antenna.

That is, as mentioned above, malfunctions of the sensing plate itself can be prevented by attaching in-phase removal filters to the supply lines and feeders, but if the load heating conductor 22 is installed on the sensing plate 21 as shown in FIG. Even if malfunction of the load heating conductor 21 itself can be prevented, as shown in Figure 11, the load heating conductor 2
2, the supply line 23 becomes an antenna, just as shown in FIG. 12, and even if the sensing plate is perfectly installed, malfunctions cannot be avoided.

For this reason, in the past, electrical equipment was not wired on the sensing plate of an automatic door. Furthermore, in extremely cold regions such as northern countries, it is not possible to install road heating near automatic doors, so a pipe that is not related to radio wave absorption is placed above the sensing plate to allow hot water to pass through. The installation work was complicated. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a sensing plate device for an automatic door which can be used as an electric device and which does not have the above-mentioned drawbacks.

Structure of the Invention; (Means for Solving the Problems) The present invention relates to an automatic door sensing plate device that can function as an automatic door sensing plate and as an electric device. The above object of the invention is to detect a frequency fluctuation and a decrease in sharpness caused by a change in the capacitance of the capacitor, which is embedded in the entrance of an automatic door and acts as a capacitor, and when a human body approaches the entrance. An automatic door sensing plate that opens and closes the automatic door; a part of the wiring placed on the automatic door sensing plate; and an electric device with the rest placed around it; and a part of the wiring and the remaining part. This is achieved by providing a chiyoke coil inserted between the two.

(Function) In this invention, in order to prevent malfunctions even when electrical equipment such as road heating is wired on the sensing plate for automatic doors, a chiyoke coil is installed between the wiring part on the sensing plate and the surrounding area. It is intervening. If there is no chiyoke coil, the radio waves from the sensing plate will flow through the electrical wiring to the power line, and not only will it malfunction, but it may not be detected even if someone approaches the sensing plate.
However, by configuring as in this invention,
It is possible to realize a sensing plate device for an automatic door that has no malfunctions.

(Embodiment) As shown in FIGS. 1 and 2, the present invention has a part 3 of wiring for electrical equipment (for example, road heating, shoe mud remover) on a sensing plate 30 for an automatic door.
At the same time, the remaining part 32 of the electrical equipment is arranged around the sensing plate 30, and the wiring 31 of the electrical equipment on the sensing board 30 is connected to the inlet/output parts 33A, 33B, 33C via the chain coils 34, 35, 36. It is designed so that it can function as a sensing plate for automatic doors and as an electrical device. In the example of FIG. 1, the wiring 31 on the sensing plate 30 and the surrounding wiring 3
In the example shown in FIG. 2, the wiring 31 on the sensing plate 30 and the surrounding wiring 32 are connected in series. There is. In the example shown in FIG. 1, two check coils 34 are inserted into the input and output parts 33A of the wiring 31, and in the example shown in FIG. are inserted respectively. Here, a power source 37 and an electric device 31
Chiyoke coil 34 connected in series between
36 is effective in removing high frequencies of the in-phase component. Note that the chain coil 34 shown in FIG. 1 may be wound in parallel around one member.

Thus, according to the chiyoke coil of the present invention, the electrical equipment and the power source are shielded from high frequency noise, so that the above-mentioned malfunction of the sensing plate does not occur.

Effects of the Invention: As described above, according to the automatic door sensing plate device of the present invention, electrical equipment is wired above and around the sensing plate, and chiyoke coils are inserted at the entrances and exits at the top and around the sensing plate. The impedance from the sensing plate side to the power source becomes high, making it possible to obtain the functions of an electrical device without impairing the original function of the sensing plate.

[Brief explanation of drawings]

Figures 1 and 2 are wiring diagrams showing a configuration example of the present invention, Figures 3A and B are structural diagrams showing how a conventional sensing plate device is buried, and Figures 4 to 6 are diagrams showing an automatic door. Figures 7A to 7C are diagrams explaining the principle of automatic door operation, Figure 8 is a diagram showing a dipole antenna,
Fig. 9A is a configuration diagram showing an example of a conventional oscillation circuit and switch circuit, Fig. 9B is a diagram showing its equivalent circuit, and Fig. 10 is a diagram showing an example of a conventional oscillation circuit and a switch circuit. Diagram showing the situation, 1st
1 and 12 are diagrams for explaining inconveniences when electrical equipment is installed. 1, 2... Sensing plate, 3... Resin frame, 4... Printed circuit board circuit (oscillation circuit), 5, 6... Lead wire, 7... Mold, 10, 11... Sensing plate, 12... High frequency oscillation circuit, 13... Switch circuit , 14, 15...power line, 21...sensing plate, 22...conductor (wiring), 23...
Power supply line, 30... Sensing plate, 31, 32... Wiring for electrical equipment, 34, 35, 36... Chi York coil,
37...Power supply.

Claims (1)

[Claims] 1. It is buried in the entrance/exit of an automatic door and acts as a capacitor, and when a human body approaches the entrance/exit,
An automatic door sensing plate that opens and closes the automatic door by detecting frequency fluctuations and sharpness reductions caused by changes in the capacitance of the capacitor, and a portion of the wiring installed on the automatic door sensing plate. an electrical device, the remainder of which is disposed around the wire, and a chiyoke coil inserted between a portion of the wiring and the remainder;
A sensing plate device for an automatic door that can be used both as an electric device and as an electric device.