JP2005174667A - Magnetic proximity sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superior magnetic proximity sensor superior in safety in which detection action is difficult to be disabled even by a permanent magnet of a dummy. <P>SOLUTION: The magnetic proximity sensor is constituted by combining a magnet block M and a sensor block S with a built-in reed switch, the sensor block S is provided with the plurality of reed switches S1, S2 and a detection circuit making action detection signal output when either one or more reed switches S1, S2 are opened or closed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetic proximity sensor using a reed switch.

Recently, in buildings such as houses, doors such as windows and doorways, and magnet blocks with permanent magnets built in doors and sensor blocks with built-in reed switches are installed in pairs. In accordance with the opening / closing operation, a security sensor of a type in which a reed switch is opened / closed to output an operation detection signal and an alarm is notified is widely adopted.
This type of security sensor uses a magnetic proximity sensor composed of a permanent magnet and a reed switch, and outputs a warning by connecting to a warning device wirelessly or by wire.
Patent Document 1 shown below describes this type of magnetic proximity sensor technology used for crime prevention.
Japanese Patent Laid-Open No. 10-12109

By the way, in the above conventional security sensor, since the permanent magnet is attached to the window, the attachment position can be visually recognized from the outside, and the general attachment position is known even if the attachment position is not visible. Many.
Therefore, it is possible for a malicious person who knows such a fact to prepare a magnet (hereinafter referred to as a dummy magnet) in order to disable detection operation using a reed switch, and to enter by opening a door or window. Sex cannot be denied.
The present invention has been proposed in view of such circumstances, and its purpose is to provide a magnetic proximity sensor that is superior in terms of safety, in which it is difficult to make the reed switch insensitive even if a dummy magnet is used. Is to provide.

In order to achieve the above object, a magnetic proximity sensor according to claim 1 is configured by combining a magnet block and a sensor block incorporating a reed switch. The sensor block includes a plurality of reed switches and a plurality of reed switches. The detection circuit is configured to output an operation detection signal when any one or more of the reed switches are opened or closed.
Here, when using a normally closed type reed switch, the plurality of reed switches and detection circuits are connected in series, and when at least one of them is opened. Outputs a detection signal, and in the case of using a normally open type reed switch, it is connected in parallel, and when at least one of them is closed, the detection signal may be output. I can do it.
In claim 2, in claim 1, the sensor block includes a plurality of reed switches whose directions are different from each other, and the magnet block includes a plurality of structures including permanent magnets corresponding to the reed switches. Each structure is arranged to face the reed switch.
According to a third aspect of the present invention, in the first aspect, the sensor block includes a plurality of reed switches whose directions are different from each other, and the magnet block integrally includes a plurality of permanent magnets facing each other in correspondence with the reed switch. It has a built-in structure.

Since the magnetic proximity sensor according to claim 1 is configured by combining a magnet block having a permanent magnet, a plurality of reed switches, and a sensor block incorporating the detection circuit, the detection circuit includes a plurality of detection circuits. When the reed switches are in a positional relationship of receiving magnetic force from the corresponding magnet blocks, no operation detection signal is output, otherwise, an operation detection signal is output.
Therefore, even if the operation of some reed switches is made insensitive by the dummy magnet, the output of the operation detection signal cannot be prohibited.
In the second and third aspects, since the magnetic flux detection directions of the plurality of reed switches are different, it is more difficult to hold all of the reed switches in an insensitive state by using one magnet. Since the magnet block is composed of individual structures with individual permanent magnets built in, the dummy magnet can be configured so that no magnetic force can be applied to all the reed switches, and has an excellent crime prevention effect. It becomes.
Further, in claim 3, since the magnet block is an integral structure including a plurality of permanent magnets, the number, position, and direction of the magnets cannot be determined from the outside, and the number of parts is small, so that the mounting work is easy. .

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

FIGS. 1A and 1B are diagrams showing the basic configuration and operation of the proximity magnetic sensor of the present invention.
Here, the sensor block S shows an example in which two reed switches S1 and S2 are connected in series.
The sensor block S incorporates reed switches S1 and S2 made of two ferromagnetic materials, each having a contact. As such reed switches S1 and S2, known ones can be adopted, and the structure thereof will be described later with reference to FIG. 1A.
According to the magnetic proximity sensor of the present invention, when the sensor block S and the magnet block M are attached to be opposed to the two members 106 and 107, respectively, as shown in FIG. Since both the reed switches S1 and S2 receive a magnetic force by the permanent magnets M1 and M2 of the magnet block M, the contact points of the two lead electrodes are magnetized to the N and S poles, and are attracted to each other to come into contact. On the other hand, when the magnet block M is moved away from the sensor block S as shown in (b) while the contact is closed, the reed switches S1 and S2 are demagnetized to open the contact.
Using this principle, the detection circuit A of the sensor block S is configured to output an operation detection signal in accordance with the opening / closing operation of the contacts of the reed switches S1 and S2.

In the example of FIG. 1, since the reed switches S1 and S2 are connected in series, an operation detection signal is not output when the respective contacts are held closed, and at least one of the reed switches S1 and S2 opens the contact. However, in the configuration in which the reed switches S1 and S2 are connected in parallel, the operation detection signal is not output when the respective contacts are held open, and the reed switches S1 and S2 are output. When at least one of S2 closes the contact, an operation detection signal may be output (see operations in FIGS. 3 and 4 described later).
FIG. 1A shows a basic structure of a reed switch built in the sensor block S.
Each of the reed switches S1 and S2 has a structure in which a pair of ferromagnetic lead wires 101 and 101 provided with contacts on the lead electrodes 102 and 102 are covered with a glass tube 103 filled with a gas 105, When an external magnetic field acts on the lead wires 101 and 101, the lead electrodes 102 and 102 of both the lead wires 101 and 101 are magnetized and are attracted to each other to close the contact point, but when the external magnetic field disappears from the lead wires 101 and 101, The structure is such that the magnetization of the lead electrodes 102 and 102 is eliminated and the contacts are opened.

FIG. 2 is an operation explanatory diagram for the dummy magnet of the magnetic proximity sensor of the present invention, and FIGS. 3 and 4 show configurations of a reed switch and a detection circuit built in the sensor block of the magnetic proximity sensor of the present invention. Yes. 3 shows a mode in which the reed switches S1 and S2 are connected in series, and FIG. 4 shows a mode in which the reed switches S1 and S2 are connected in parallel.
As shown in FIG. 5, the magnetic proximity sensor of the present invention has a magnet block M attached to the open / close door W2 and a sensor block S attached to the door frame W1, or the magnet block M is attached to the window sash 200 as shown in FIG. In addition, the sensor block S is used by being attached to the window frame 201.

In the magnetic proximity sensor configured as described above, the magnet block M is attached particularly in the structure in which the reed switch and the detection circuit as shown in FIG. 3 are built in the sensor block. When the window is closed, since the two pairs of magnets M1, M2 and the reed switches S1, S2 are close to each other, the contacts of the reed switches S1, S2 are both closed. Since the magnets M1, M2 and the reed switches S1, S2 are separated from each other, the contacts are both opened, and the magnetic proximity sensor S transmits an operation detection signal at that time.
Therefore, even if the dummy magnet m is brought close to the sensor block S from the outside through the sash or window glass, the reed switch S1 on the side close to the dummy magnet m keeps the contact closed, but the other reed switch S2 The magnetic force does not act. Therefore, when the window is opened, the corresponding permanent magnet of the magnet block M is separated from the other reed switch S2, so that the contact of the reed switch S2 is opened, and the detection circuit A outputs an operation detection signal. An alarm is output from the receiver that has received the motion detection signal.
That is, according to the configuration of such a magnetic proximity sensor, even if a malicious person tries to hold the reed switches S1 and S2 in the closed state using the dummy magnet m that he / she owns, all of the magnetic force by the dummy magnet m is obtained. This does not act on the reed switches S1 and S2, and as a result, the output of the operation detection signal from the sensor block S of the magnetic proximity sensor cannot be prohibited, so that the alarm operation cannot be easily stopped.

6A and 6B are views showing the positional relationship between a sensor block and a magnet block in another example of the proximity magnetic sensor of the present invention.
Here, FIG. 6A is composed of one sensor block S and two magnet blocks MA and MB. Between the two reed switches S1 and S2 incorporated in the sensor block S, The magnetic buffer layer BF is provided, and the magnetic force generated by the permanent magnets M1 and M2 incorporated in the corresponding magnet blocks MA and MB leaks to the other reed switches S2 and S1, and the respective contacts are not simultaneously opened and closed. ing. Here, since the magnetic buffer layer BF forms a parallel magnetic flux circuit together with the reed switch S1 when the reed switch S1 receives a magnetic force by the permanent magnet M1, it is desirable to form the magnetic buffer layer BF from a material having a small magnetic resistance. However, instead of such a buffer layer, a ferromagnetic material (not shown) is added to both ends of the reed switches S1 and S2, and the magnetic lines of force of the permanent magnets M1 and M2 can easily pass through the reed switches S1 and S2. It may be.
Such a magnetic material buffer layer BF and the ferromagnetic material added to the reed switches S1 and S2 are only from the permanent magnets M1 and M2 incorporated in the magnet blocks MA and MB corresponding to one of the reed switches S1 and S2. Needless to say, a structure that allows the magnetic force to pass therethrough is desired, and if there is such an action, other alternative means can be adopted as appropriate.
In FIG. 6B, since the directions of the reed switches S1 and S2 are different, the magnetic buffer layer BF is not provided, but the magnetic force by the permanent magnets M1 and M2 incorporated in the corresponding magnet blocks MA and MB is different from that of the other. It is desirable to provide it when there is a possibility that the contacts may be simultaneously opened and closed due to leakage to the reed switches S2 and S1.

FIG. 7 is a diagram showing a positional relationship between a sensor block and a magnet block in another example of the proximity magnetic sensor of the present invention.
In this example, one sensor block S is combined with one magnet block M ′, but a plurality of permanent magnets M1 and M2 are integrally incorporated in the magnet block M ′.

FIGS. 8A and 8B are diagrams illustrating an example in which the proximity magnetic sensor shown in FIG. 7 is used as a security sensor.
Here, the example attached to the sliding window sash 200 and the window frame 201 is shown. The integrally formed magnet block M ′ has a U-shaped cross section and is attached to the indoor side surface of the window sash 200 so that the plurality of permanent magnets M1 and M2 are arranged to face each other through a space. The other sensor block S is formed in a size that can be accommodated according to the space of the magnet block M ′, and is attached to the window frame 201.
In such a structure, when the window is closed, the sensor block S is surrounded by the magnet block M ′, and when the window is opened, the magnet block M ′ is separated from the sensor block S. The contacts of the switches S1 and S2 are opened and an alarm is output.
As described above, there are various ways of attaching the plurality of reed switches S1 and S2, but in any case, from the outside of the window, the dummy magnets can simultaneously hold the plurality of reed switches in the insensitive state. In particular, if at least one reed switch S1 (S2) is attached to the bottom surface or indoor surface of the sensor block body S or the direction thereof is changed, the insensitive operation by the dummy magnet from the outside becomes almost impossible, and it is more excellent. You can get a crime prevention effect.

FIG. 9 shows various modifications of the magnet block M used in the magnetic proximity sensor of the present invention.
(A) is a mode corresponding to the case where the reed switches S1 and S2 are mounted on the same surface of the sensor block S, and the permanent magnets M1 and M2 are arranged in the same direction (a-1), and the permanent magnet M1. , M2 are arranged in a direction orthogonal to each other (a-2). In addition, (a-3) is a character in which characters such as “being crime-preventing” are written on the outer surface when it is attached to a window for use.
Such a magnet block M has an effect of concealing the built-in permanent magnets and also has an effect of preventing the number, position, and direction of the permanent magnets from being determined from the outer surface, but the insensitive operation by the dummy magnets is more difficult. It is desirable to have structural features that make
FIG. 9B shows an example of a magnet block M used for the sensor block S with the reed switches S1 and S2 attached to the side and bottom surfaces, and (b-1) shows a permanent magnet. (B-2) shows a configuration in which the axes of the permanent magnets M1 and M2 are arranged in the same direction. It goes without saying that the plurality of permanent magnets with different directions built into the magnet block M are not necessarily limited to orthogonal ones.

10 and 11 show examples in which the magnetic proximity sensor of the present invention is used as a security sensor. FIG. 10 shows an example of use as a wireless security sensor SA. If the wireless transmission unit 10 is additionally connected to the sensor block S of the security sensor SA, and the detection circuit described above outputs an operation detection signal, The wireless security receiver 20 outputs an alarm or notification. The wireless transmission unit 10 may be built in the sensor block S.
FIG. 11 is a diagram showing an example of use as the wired security sensor SB. A plurality of sensor blocks S... Are wired through signal lines L to form a monitoring loop. If any of the sensor blocks S outputs an operation detection signal, a security receiver connected to the signal lines L. 30 outputs an alarm or notification.

(A), (b) is the basic composition and operation explanatory drawing of the magnetic proximity sensor of the present invention. It is a figure which shows the basic structure of the reed switch incorporated in the sensor block. It is operation | movement explanatory drawing of a sensor block at the time of using a dummy magnet. (A), (b) is a figure explaining an example of a detection circuit, and its operation | movement. (A), (b) is a figure explaining the other example of a detection circuit, and its operation | movement. It is a figure which shows the example which uses the magnetic proximity sensor of this invention as a security sensor. (A), (b) is a figure which shows the positional relationship of the sensor block and magnet block in the other example of the magnetic proximity sensor of this invention. It is a figure which shows the positional relationship of the sensor block in another example of the magnetic proximity sensor of this invention, and a magnet block. (A), (b) is a figure explaining the example and operation | movement which use the magnetic proximity sensor shown in FIG. 7 as a security sensor. (A), (b) is a figure which shows the various deformation | transformation aspect of a magnet block. It is a figure which shows the example which used the magnetic proximity sensor as a wireless security sensor. It is a figure which shows the example which used the magnetic proximity sensor as a wire-type crime prevention sensor.

Explanation of symbols

S Sensor block S1, S2 Reed switch M, MA, MB, M 'Magnet block M1, M2 Permanent magnet A Detection circuit m Dummy magnet SA Wireless security sensor SB Wired security sensor

Claims (3)

Magnetic proximity that combines a magnet block and a sensor block with a built-in reed switch, and opens and closes the reed switch and outputs a detection signal according to the contact / separation operation between the magnet block and the sensor block. In the sensor
The sensor block includes a plurality of reed switches and a detection circuit that outputs an operation detection signal when any one or more of the reed switches are opened or closed. Magnetic proximity sensor. In claim 1,
The sensor block contains a plurality of reed switches whose directions are different from each other.
The magnetic proximity sensor, wherein the magnet block is configured as a plurality of structures including permanent magnets corresponding to the reed switch, and each structure is disposed to face the reed switch. In claim 1,
The sensor block contains a plurality of reed switches whose directions are different from each other.
The magnetic proximity sensor, wherein the magnet block has a structure in which a plurality of permanent magnets facing each other corresponding to the reed switch are integrated.