JPS6133796B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that detects an object by a change in capacitance, and more particularly to a proximity detection device that can prevent erroneous door opening/closing operations immediately before the door is in a fully closed position.

The proximity detection device is attached to the front edge of the door of an elevator, etc., and detects a person or object on the path of the door without contact when the door is closed or fully opened, and then reverses the door or stops the door from starting to close. It is used to make someone do something.

As this type of proximity detection device, there is one constructed as shown in FIGS. 1 and 2.

In Figure 1, 1 is the detection object installed at the front edge of the door;
2 is an antenna that constitutes the detection object 1, 2a is a connection line of the antenna 2, 3 is a shield plate that constitutes the detection object 1, 4 is the ground capacitance of the antenna 2, and 5 is a detection unit that An oscillation circuit 6 whose resonant circuit includes a capacitance 4 and a variable reactance circuit that can be changed by an electric signal (for example, the reactance of a variable capacitance element depending on a voltage), and a frequency-voltage conversion circuit 7 that generates a voltage corresponding to the oscillation frequency of the oscillation circuit 6. , a delay feedback circuit 8 which gives a time delay to the output of the frequency-voltage conversion circuit 7 and provides negative feedback to the variable reactance circuit in the oscillation circuit 6 so as to cancel out the ground capacitance 4. Reference numeral 9 denotes an output section, and an AC amplifier circuit 10 that selectively amplifies the variation in the output 5a of the detection section 5;
A polarity discrimination circuit 11 that discriminates between positive and negative output pulses of the AC amplifier circuit 10, a flip-flop circuit 12 that is set by the positive pulse output 11a and reset by the negative pulse output 11b, and a flip-flop circuit 12.
An output relay 1 that outputs a door reversal command or a command 9a that creates a condition to prevent the door from starting to close.
Consists of 3.

In FIG. 1, when an object approaches the antenna 2, the ground capacitance 4 increases, the oscillation frequency of the oscillation circuit 6 decreases, and the output of the frequency-voltage conversion circuit 7 increases. This output 5a is applied to the variable reactance circuit in the oscillation circuit 6 through the delay feedback circuit 8 so as to cancel out the increase in the ground capacitance 4. Therefore, a positive pulse output is obtained at the output 5a for a time corresponding to the time delay of the delayed feedback circuit 8. Conversely, when the object moves away from the antenna 2, the ground capacitance 4 decreases, the output of the frequency-voltage conversion circuit decreases, and the output 5a is connected to the delay feedback circuit 8.
A negative pulse output is obtained for a time corresponding to the time delay of . In the AC amplifier circuit of the output section 9, the output 5a
Only the positive pulses and negative pulses are selectively amplified, and the polarity discrimination circuit 11 generates a positive pulse output 11a and a negative pulse output 11b as outputs. Positive pulse output 11
The flip-flop circuit 12 is set by a, energizes the output relay 13, and outputs an output 9 as a door reversal command or a command to stop the door from starting to close.
generate a. The flip-flop circuit 12 is reset by the negative pulse output 11b, canceling the above-mentioned set condition and preparing to begin closing the door.

That is, when the door is fully open, the flip-flop circuit 12 is set by the positive pulse output 11a generated when an object approaches the antenna 2, and issues a command to prevent the door from starting to close. If the object remains close to the antenna 2, the flip-flop circuit 12
remains set and the command to stop the door from starting to close is maintained.

Next, when the object leaves the antenna 2, a negative pulse output 11b is generated and preparations are made to start closing the door.

When the proximity detection device as described above is applied to a double sliding door, it may be configured as shown in FIG. 2.

In the figure, detecting bodies 1a and 1b are installed at the front edges of doors 14a and 14b, and antennas 2a and 2b inside the detecting bodies 1a and 1b are connected by connection lines 2aa and 2ba, and are connected to a detecting section 5. Both doors 14a,
A change in the sum of the ground capacitances 4a and 4b of the antennas 2a and 2b arranged at the antenna 14b is converted into an electric signal by the detection unit 5, and the output unit 9 detects the approach or separation of an object from the antenna. 15 is a cam provided on the door 14a, 16 is a switch provided on the fixed part, and the switch 16 is operated by the cam 15 from the position immediately before fully closing the doors 14a and 14b to the fully closed position,
It emits an output 16a. When the door is close to fully closed, the antennas 2a and 2b detect the opposing doors 14b and 14a, and the panels 3b and 3a, respectively, and the switch 16 is activated to prevent the door from becoming impossible to close. The output 16a controls the amplification degree of the AC amplifier circuit 10 of the output section 9 to lower the detection sensitivity.

As shown in FIG. 2, both doors 14a, 14b
Ground capacitances 4a, 4b of antennas 2a, 2b
The sum of antennas 2a, 2b and shielding plate 3a,
3b structure, detecting objects 1a and 2a are connected to doors 14a and 14
For example, the state when installing in door 14a, 14b
Depending on whether it is grounded or insulated, etc.
In addition, in elevators, the characteristic curve of ground capacitance differs depending on the material of the door at each landing, such as whether the door is made of metal or resin, as shown in Figure 3. Become something.

That is, in FIG. 3, characteristic curves A and D show typical examples of characteristics, and curves B and C correspond to the above-mentioned curves A and D.
This shows a case where the following are complicatedly mixed. First, characteristic curve A is for an elevator with a grounded door or doorstop made of metal facing the detection side of the antennas 2a and 2b, and when the detection side approaches the grounded door, etc. It shows that the capacitance increases monotonically as the state becomes fully closed.

Next, characteristic curve D is obtained when both the detection side of antennas 2a and 2b and the metal material facing this detection side or the left and right antennas 2a and 2b of a double door are electrically connected and configured to have the same potential. Alternatively, if the door, doorstop, etc. that houses the antennas 2a and 2b are made of resin, etc., the influence of the door, doorstop, etc. facing the detection side is extremely small, and as the door becomes fully closed. This shows that the number of grounded metal bodies (for example, sill materials, etc.) detected by the antennas 2a and 2b decreases, and the ground capacitance decreases monotonically.

Furthermore, the characteristic curve B or C indicates that the antennas 2a and 2bb on the detection side are electrically connected, and the left and right doors (panels) that house the antennas 2a and 2b are connected to each other.
is grounded, the effect of the other door (panel) is that as the doors get closer to each other, the ground capacitance increases, and that the sills other than the other door
This is a case where the ground capacitance decreases as the doors approach each other due to the effects of rails, etc., which are complicatedly intertwined. In other words, characteristic curve B is a case in which the influence of the other door is greatly apparent from a distance, and the influence of the sill, rail, etc. does not appear unless you are very close, and between the operation start point P ₃ and the fully closed point P ₂ shows that the ground capacitance increases once and then decreases. In addition, characteristic curve C, contrary to curve B above, appears only when the influence of the other door is extremely close,
This is a case where the influence of the sill, rail, etc. is greatly visible from a distance, and the ground capacitance decreases once and then increases between the operation start point P ₃ and the fully closed point P ₂ .

In FIG. 3, P ₁ is the fully open position of the doors 14a and 14b, P ₂ is the fully closed position, and P ₃ is the starting point of the switch 16. In the case of characteristics A to C in which the sum of ground capacitances 4a and 4b tends to increase near the fully closed position _P2 when the door is closed, this is equivalent to when an object approaches antenna 2a or antenna 2b, resulting in malfunction. However, the amplification degree of the AC amplifier circuit 10 of the output section 9 is controlled so that the switch 16 operates at position _P3 and its output 16a does not lead to malfunction and the detection operation continues with the switch fully closed. .

Similarly, when the doors 14a, 14b start opening operation from the fully closed position _P2 , if the sum of the ground capacitances 4a, 4b tends to increase, in the case of characteristics B to D, there is no object on the antennas 2a, 2b. However, in the case of the above characteristic B, the ground capacitance decreases and the flip-flop circuit 1
2 is reset and no malfunction occurs. but,
In the case of characteristics C and D, the door is not reset and remains fully open, making it impossible to close the door thereafter.

Such malfunctions can be prevented by controlling the amplification degree of the AC amplifier circuit 10 using the output 16a of the switch 16 when the door is opened as well as when the door is closed. However, since priority may be given to ensuring detection sensitivity near the fully closed position P ₂ when the door is closed, when the door opening speed is faster than the door closing speed near the fully closed position P ₂ , the capacitances 4a and 4b are The rate of change is different, making it essentially difficult to eliminate malfunctions. In addition, the output 16a of the switch 16
Accordingly, it is possible to control the degree of amplification of the AC amplifier circuit 10 by distinguishing between when the door is closed and when the door is open, but this has the disadvantage that the device becomes complicated.

The present invention is intended to improve the above-mentioned problems, and aims to provide a proximity detection device that eliminates malfunctions when opening a door from a closed position and that operates stably. The proximity detection device according to the present invention detects the proximity or separation of an object from a change in ground capacitance of an antenna placed at the front edge of a door that automatically opens and closes, and outputs this as a voltage value. an output section that amplifies the output voltage value of the detection section, discriminates the polarity of the amplified detection result, and outputs a signal for controlling the opening/closing state of the door based on the discriminated polarity; A switch that operates between a position immediately before the door is fully closed and a fully closed position that causes disturbance in the ground capacitance of the antenna, and an output that controls the output section based on the operation of this switch,
The output section control section holds the output section when the door is open and inverts it when the door is closed by using the output of the output section, and the output section control section holds the output section when the door is open or closed, and inverts it when the door is closed. This configuration eliminates the influence of capacitance disturbances on the detection unit.

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 4, an output 16a of a switch 16 for detecting the positions of doors 14a and 14b controls the amplification degree of an AC amplifier circuit 10 at the output section, and is also applied to a reset signal generating circuit 17. The reset signal generating circuit 17 generates a reset pulse 17a when the output 16a of the switch 16 disappears at position _P3 in FIG.
2.

The proximity detection device constantly detects door 14.
When the antennas 2a, 14b are in the fully open position, the antennas 2a,
When an object approaches 2b, the flip-flop circuit 12 is set, and the output 9a of the output section 9 prevents the doors 14a and 14b from starting to close. When an object approaches the antennas 2a and 2b during the door closing operation, the flip-flop circuit 12 is set, and the output 9a of the output section 9 prevents the doors 14a and 14b from closing, and causes the door to open. This prevents the door from being caught between the doors 14a and 14b. Door 1
4a, 14b near the fully closed position during the door closing operation, the switch 16 is actuated by the cam 15, and the output 16a controls the amplification degree of the AC amplifier circuit 10 of the output section 9 to decrease, and the antennas 2a, 2
Doors 14a, 14b facing b and palm plate 3
a and 3b are not detected, the output from the AC amplifier circuit 10 to the polarity discrimination circuit 11 is stopped, and the flip-flop circuit 12 is maintained as it is without being set or reset. When the doors 14a, 14b open from the fully closed position, the sum of the ground capacitances 4a, 4b increases due to the influence of the palms and the plates 3b, 3a of the doors 14b, 14a, which the antennas 2a, 2b face, Flip-flop circuit 12 is set. Furthermore, when the doors 14a and 14b are opened and the switch 16 is removed from the cam 15, and the output 16a is no longer emitted, the flip-flop circuit 12 is reset by the reset signal generating circuit 17, and the door 14 is
This prevents the flip-flop circuit 12 from remaining set when the flip-flop circuits a and 14b are fully open.

In the above embodiment, the antennas 2a and 2b of the detection bodies 1a and 1b installed on the doors 14a and 14b are
Although the description has been made of a self-balanced type in which there is one delay feedback circuit 8 in each case, it is clear that the same function can be obtained by the device described below.

(a) A self-balancing type different from the above embodiments, or a type that converts changes in ground capacitance due to proximity and separation of objects into pulses.

(b) A plurality of antennas are provided in the detection bodies 1a and 1b, and the ground capacitance of each antenna constitutes an impedance bridge, and a flip-flop circuit or counter circuit etc. A device that stores the proximity of an object and releases the memory when the object moves away from the antenna.

(C) A type in which a plurality of switches are provided that operate depending on the position of the doors 14a and 14b, and the switch that controls the amplification level when the door is closed and the switch that generates the reset signal when the door is opened are differentiated.

As explained above, the present invention detects when the door is opened based on the detection results of the switch that detects the operating state of the door between the position immediately before the door is fully closed and the fully closed position, which causes disturbance of the ground capacitance of the antenna. A control signal is sent from the output unit control unit to the output unit to hold this value and invert it when the door is closed. Since the structure eliminates this, malfunctions in opening and closing the door can be prevented, and the door can be opened and closed stably.

[Brief explanation of the drawing]

Figure 1 is a block circuit diagram of a conventional proximity detection device, Figure 2 is a configuration diagram of a conventional proximity detection device applied to a double sliding door, and Figure 3 is the ground capacitance of the antenna depending on the position of the door in Figure 2. FIG. 4 is a diagram corresponding to FIG. 2 showing an embodiment of the proximity detection device according to the present invention. 1a, 1b... Detection object, 2a, 2b... Antenna, 4a, 4b... Ground capacitance, 5... Detection section, 9... Output section, 10... AC amplifier circuit, 11
... Polarity discrimination circuit, 12 ... Flip-flop circuit, 13 ... Output relay, 14a, 14b ...
Door, 15...Cam, 16...Switch, 17...
In the reset signal generation circuit, the same parts in the figures are indicated by the same reference numerals.

Claims (1)

[Claims] 1. A detection unit that detects the approach or separation of an object from changes in ground capacitance of an antenna placed at the front edge of a door that automatically opens and closes, and outputs this as a voltage value. , an output section that amplifies the output voltage value of the detection section, discriminates the polarity of the amplified detection result, and outputs a signal for controlling the opening/closing state of the door based on the discriminated polarity; A switch operates between the position immediately before the door is fully closed and the position where the door is fully closed, which causes disturbance in the ground capacitance, and an output is sent out to control the output section based on the operation of this switch. and an output control section that holds the output section when the door is open and reverses it when the door is closed, and a detection section that detects disturbances in the ground capacitance of the antenna. A proximity detection device characterized by having a configuration that eliminates the influence on 2. A proximity detection device characterized in that the output section control section is configured to send a reset signal to a flip-flop of the output section which is set/reset according to the discriminated polarity.