Door magnetic alarm for fire exit door

Abstract

The utility model discloses a door magnetic alarm for a fire exit door, which belongs to the technical field of door magnetic alarms and comprises an alarm shell and a permanent magnet shell, and a protection mechanism is arranged in the inner wall of the alarm shell. By adding the protection mechanism, when the toothed plate and the magnet move along with the door plate and get away from or get close to the door magnetic switch, the toothed plate and the magnet can keep meshing with the driving gear at the bottom of the door magnetic switch under the pulling and rotating action of the spring and the hinge seat, and drive the rotating driving gear to drive the worm to drive the worm gear to rotate, so that the magnetic blocking grating is opened or closed; therefore, when the magnet is far away from the door magnetic switch, one side of the door magnetic switch is of the magnetism blocking sealing structure, a new magnet is prevented from approaching and inducing the door magnetic switch to recognize closing of the door, when the door plate is closed and the magnet returns, the magnetism blocking grating is opened, the magnetic field of the door plate magnet acts on the magneto-dependent sensor again, and closing of the door can be correctly recognized. The normally-closed fire exit door is effectively monitored, and fire-fighting hidden dangers caused by malicious long-term opening of the normally-closed fire exit door are prevented.

Description

Technical Field

[0001] This utility model relates to the field of door magnetic alarm technology, and in particular to a door magnetic alarm for fire doors. Background Technology

[0002] A door magnetic alarm consists of two parts: a switch and a magnet. The switch is a reed switch connected by a lead wire and encapsulated. The magnet is a magnet of corresponding magnetic field strength encapsulated in a plastic or alloy housing. When the two are separated or brought close to a certain distance, the switch is activated, thereby sensing the change in the position of the object. It is generally used in urban security applications.

[0003] In existing door magnetic alarm switches, the switch and the magnet are in a corresponding state. When the door is opened, the magnetic reed in the switch loses its magnetic field and triggers the alarm circuit. When the door is closed, the conductive sheet inside the magnetic reed is remagnetized and connected, thus disconnecting the alarm circuit.

[0004] The drawback of this structure is that, when the door is open but not closed, replacing the magnet on the door with a magnet of the same magnetic field strength and bringing it close to the door magnetic switch can induce the door magnetic switch to recognize that the door is closed. The alarm circuit can also be automatically disconnected or remotely manually disconnected, thus losing the function of the door magnetic alarm. For normally closed fire doors, users may use this method to keep the door open for convenience without triggering the alarm, which is not effectively monitored and increases the risk of fire.

[0005] To address the aforementioned issues, a magnetic door alarm for fire doors is proposed. Utility Model Content

[0006] The main purpose of this utility model is to provide a door magnetic alarm for fire doors, which solves the problems mentioned in the background art.

[0007] The objective of this utility model can be achieved by adopting the following technical solution:

[0008] A door magnetic alarm for fire doors includes an alarm housing and a permanent magnet housing, wherein a protective mechanism is provided in the inner wall of the alarm housing;

[0009] The protective mechanism includes a magnetic shielding grille rotatably mounted to the inner wall of the alarm housing. A worm gear is nested on one end of the magnetic shielding grille shaft, and a worm is meshed on one side of the worm gear. The bottom end of the worm passes through the alarm housing and is fitted with a drive gear. A toothed plate with a toothed structure meshes on the outer side of the drive gear.

[0010] Furthermore, the protective mechanism also includes a first fixing frame and a second fixing frame fixed at one corner of the bottom of the alarm housing and the permanent magnet housing.

[0011] Furthermore, one end of the toothed plate is rotatably mounted to the second fixed frame via a hinge seat, and a spring is clamped between the inner sidewall of the toothed plate and the inner wall of the second fixed frame.

[0012] Furthermore, the exterior of the magnetic shielding grille is provided with a sealing plate of the same material as the alarm housing and integrally installed.

[0013] Furthermore, a control circuit board is horizontally placed inside the alarm housing, and a lithium battery is electrically connected to the top of the control circuit board. A magnetic sensor is fixed to one side of the outer wall of the control circuit board by a bracket, and a permanent magnet is encapsulated inside the permanent magnet housing.

[0014] Furthermore, the alarm housing is fixed to the door frame, and the permanent magnet housing is fixed to the door panel.

[0015] The beneficial technical effects of this utility model are as follows:

[0016] This invention adds a protective mechanism to a traditional magnetic door alarm. The toothed plate and magnet follow the movement of the door panel, moving away from or near the magnetic door switch. Under the pulling and rotating action of the spring and hinge seat, they maintain engagement with the drive gear at the bottom of the magnetic door switch, causing it to rotate. The drive gear drives the worm gear to rotate, opening or closing the magnetic barrier. Thus, when the magnet is away from the magnetic door switch, one side of the switch has a magnetic barrier sealing structure, preventing new magnets from approaching and inducing the magnetic door switch to recognize the door as closed. When the door panel closes and the magnet returns, the magnetic barrier opens, and the magnetic field of the door panel magnet acts on the magnetic sensor again, correctly recognizing the door as closed. This effectively monitors normally closed fire doors, preventing them from being maliciously opened for extended periods and posing fire hazards. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a preferred embodiment of a magnetic door alarm for fire doors according to the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of a preferred embodiment of a magnetic door alarm for fire doors according to the present invention, after removing the door frame and door panel;

[0019] Figure 3 This is a schematic diagram of the structure of the alarm housing and the permanent magnet housing after separation in a preferred embodiment of a door magnetic alarm for fire doors according to the present invention;

[0020] Figure 4 This is a schematic diagram of the internal structure of the alarm housing in a preferred embodiment of a magnetic door alarm for fire doors according to the present invention;

[0021] Figure 5In a preferred embodiment of a magnetic door alarm for fire doors according to this utility model, Figure 4 Enlarged view of point A in the middle.

[0022] The annotations in the attached figures are explained as follows:

[0023] 1. Door frame; 2. Door panel; 3. Alarm housing; 301. Control circuit board; 302. Lithium battery; 303. Magnetic sensor; 4. Permanent magnet housing; 401. Permanent magnet; 5. Protective mechanism; 501. Magnetic barrier; 502. Worm gear; 503. Worm; 504. Drive gear; 505. First fixed frame; 506. Second fixed frame; 507. Toothed plate; 508. Hinge seat; 509. Spring; 6. Sealing plate. Detailed Implementation

[0024] To enable those skilled in the art to understand the technical solution of this utility model more clearly, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of this utility model is not limited thereto.

[0025] like Figures 1-5 As shown, this embodiment provides a door magnetic alarm for fire doors, including an alarm housing 3 and a permanent magnet housing 4. A protective mechanism 5 is provided in the inner wall of the alarm housing 3. The protective mechanism 5 includes a magnetic blocking grille 501 rotatably mounted to the inner wall of the alarm housing 3. A worm gear 502 is nested on a shaft at one end of the magnetic blocking grille 501. A worm 503 is meshed on one side of the worm gear 502. The bottom end of the worm 503 passes through the alarm housing 3 and is fitted with a drive gear 504. A toothed plate 507 with a toothed structure meshes on the outer side of the drive gear 504.

[0026] In the above structure, the worm gear 502 and the worm 503 are both encapsulated in the inner wall of the alarm housing 3. The magnetic blocking grille 501 is made of magnetic shielding material, such as ferrite, permalloy, etc. After the magnetic blocking grille 501 rotates and closes, it forms a magnetic shielding wall, thereby achieving the purpose of shielding the magnetic field, changing the effect of the magnetic field on the magnetic sensor 303, and realizing the purpose of preventing external magnetic elements from inducing the magnetic sensor 303.

[0027] The protective mechanism 5 also includes a first fixing frame 505 and a second fixing frame 506 fixed at one corner of the bottom of the alarm housing 3 and the permanent magnet housing. The first fixing frame 505 serves to protect the drive gear 504, and the second fixing frame 506 serves to support the rotation of the toothed plate 507.

[0028] One end of the toothed plate 507 is rotatably mounted to the second fixed frame 506 via a hinge seat 508. A spring 509 is clamped between the inner side wall of the toothed plate 507 and the inner wall of the second fixed frame 506. When the toothed plate 507 moves in and out of the first fixed frame 505, it follows the door panel 2 in an arc motion. However, since the other end is in a hinged state and is pulled by the spring 509, it can mesh with the teeth of the drive gear 504 during the arc motion.

[0029] The magnetic blocking grille 501 is equipped with a sealing plate 6 made of the same material as the alarm housing 3 and installed as a single piece. This arrangement is to maintain the airtightness of the alarm housing 3 without affecting the entry of the magnetic field.

[0030] Inside the alarm housing 3, a control circuit board 301 is horizontally mounted. A lithium battery 302 is electrically connected to the top of the control circuit board 301. A magnetic sensor 303 is fixed to one side of the outer wall of the control circuit board 301 via a bracket. A permanent magnet 401 is encapsulated inside the permanent magnet housing 4. The magnetic sensor 303 is a reed switch. The reed switch consists of two reeds (usually composed of iron and nickel) sealed inside a glass tube. The two reeds overlap but have a small gap between them. A suitable external magnetic field will cause the two reeds to contact.

[0031] The alarm housing 3 is fixed to the door frame 1, and the permanent magnet housing 4 is fixed to the door panel 2.

[0032] The working principle of this device is as follows: When in use, the permanent magnet housing is fixed to the door panel 2, and the alarm housing 3 is fixed to the door frame 1, and the two are installed in alignment.

[0033] When door panel 2 is opened, the permanent magnet housing follows door panel 2 in an arc motion. At this time, toothed plate 507 is in an inclined state and is pulled and pressed onto drive gear 504 by spring 509. When toothed plate 507 slides out of first fixed frame 505, it also makes an arc motion and meshes with drive gear 504 to rotate. Drive gear 504 drives worm 503 at the top to rotate. Worm 503 drives worm wheel 502 to rotate, closing the magnetic barrier grille 501 in the forward direction and keeping the gaps between adjacent magnetic barrier grilles 501 seamless, thus isolating the magnetic field. After the magnetic sensor 303 loses the magnetic field, it disconnects and triggers the voltage monitoring unit on control circuit board 301 to identify that the door has been opened and then activates the alarm to provide an external warning.

[0034] When the door panel 2 returns to its closed position, the toothed plate 507 also makes an arc motion. The inclined toothed plate 507 enters the first fixed frame 505 and abuts against the teeth of the drive gear 504. Under the action of the thrust and the downward pressure of the spring 509, it applies a reverse rotational force to the drive gear 504, so that the magnetic blocking grille 501 is opened, and the magnetic field of the permanent magnet 401 can act on the magnetic sensor 303, so that the monitoring circuit can recognize that the door is closed and can stop the alarm.

[0035] By adopting the above structure, when the door is open but not closed, it is possible to prevent the use of magnetic materials with the same strength as permanent magnet 401 to induce the door magnetic switch to recognize the door closing signal, which in turn facilitates the safe closing of normally closed fire doors in corridors and avoids fire hazards.

[0036] The above are merely further embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed by this utility model, based on the technical solution and concept of this utility model, shall fall within the protection scope of this utility model.

[0037] All standard parts used in this application can be purchased from the market, and can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art. The control method is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art and is common knowledge in the field. Since this application is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail in this application.

Claims

1. A door magnetic alarm for fire doors, comprising an alarm housing (3) and a permanent magnet housing (4), characterized in that: A protective mechanism (5) is provided in the inner wall of the alarm housing (3). The protective mechanism (5) includes a magnetic shield (501) rotatably mounted to the inner wall of the alarm housing (3). A worm gear (502) is nested on one end of the magnetic shield (501). A worm (503) is meshed on one side of the worm gear (502). A drive gear (504) is fitted after the bottom end of the worm (503) passes through the alarm housing (3). A toothed plate (507) with a toothed structure meshes on the outer side of the drive gear (504).

2. A door magnetic alarm for fire doors according to claim 1, characterized in that: The protective mechanism (5) further includes a first fixing frame (505) and a second fixing frame (506) fixed at one corner of the bottom of the alarm housing (3) and the permanent magnet housing.

3. A door magnetic alarm for fire doors according to claim 2, characterized in that: One end of the toothed plate (507) is rotatably mounted to the second fixed frame (506) via a hinge seat (508), and a spring (509) is clamped between the inner side wall of the toothed plate (507) and the inner wall of the second fixed frame (506).

4. A door magnetic alarm for fire doors according to claim 3, characterized in that: The magnetic shielding grille (501) is provided with a sealing plate (6) of the same material as the alarm housing (3) and installed integrally.

5. A door magnetic alarm for fire doors according to claim 4, characterized in that: The alarm housing (3) has a horizontally placed control circuit board (301) inside. The top of the control circuit board (301) is electrically connected to a lithium battery (302). A magnetic sensor (303) is fixed to one side of the outer wall of the control circuit board (301) by a bracket. The permanent magnet housing (4) has a permanent magnet (401) encapsulated inside.

6. A door magnetic alarm for fire doors according to claim 5, characterized in that: The alarm housing (3) is fixed on the door frame (1), and the permanent magnet housing (4) is fixed on the door panel (2).

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