KR20100012670A

KR20100012670A - Door release device for fire door

Info

Publication number: KR20100012670A
Application number: KR1020080074185A
Authority: KR
Inventors: 신양섭
Original assignee: 삼화금속 주식회사
Priority date: 2008-07-29
Filing date: 2008-07-29
Publication date: 2010-02-08

Abstract

The present invention discloses a door release device for a fire door. The present invention provides a case having a hook insertion port to which the hook provided in the fire door enters and exits; A hinge assembly inside the case to lock and release the hook of the fire door by forward and reverse rotation, and a hook holder having a driven gear on one side of the outer periphery; An interlock shaft that is rotatably supported by the case with a driving gear engaged with the driven gear of the hook holder; A release motor having a reduction gear having a deceleration force greater than a closing force acting on the fire door, so as to be electrically coupled with the interlock shaft, and the hook holder being driven in a direction to release the locking of the hook according to an external fire detection signal; do.

The present invention can not only easily close the fire door as necessary during fire or non-fire, but also reliably prevent the release of the fire door by the impact from the outside in the open state of the fire door.

Description

Door release device for fire doors

The present invention relates to a fire door that is installed in the entrance or passage of various building structures to prevent the spread of flames and smoke to an adjacent area in the event of a fire. More specifically, the fire door in the case of non-fire The present invention relates to a door release device for a fire door that is restrained in an open state and automatically releases restraint of a fire door in case of fire.

In general, various building structures have passages for entry and exit, especially in large buildings such as buildings or apartments where many people reside in the building, and several passageways such as elevators and emergency stairs and / or corridors are provided together. have.

Therefore, in the event of a fire, there is a high possibility that the flames will spread rapidly through these passages and spread to a large fire disaster, and in fact, many fire accidents in apartments have led to large fires by spreading the flames rapidly through these passages. .

As a result, mandatory installation of fire doors that block spaces in order to suppress or delay the spread of fire in case of emergency in the case of large group residential buildings such as buildings and apartments, in particular, the entrance and the boundary of each passage, etc. have.

For example, as shown in FIG. 1, the fire door D is provided with a rotational force in the closing direction by a door closer C, an auto hinge, or the like, and is applied to the wall W of the building. Normally lock the hook (H) of the fire door (D) to lock the door (D) in the open state, and release the restraint of the hook (H) in response to the fire signal of the fire detection means (not shown) As a result, the door release R is installed and configured to automatically close the fire door D.

On the other hand, the fire door (D) is required to be artificially closed as needed even during normal (non-fire), but should not be abnormally closed in the undesired situation, for example by a physical impact from the outside.

Therefore, in the fire door (D), the function of the door release (R) is very important because the door release (R) for restraining and releasing the fire door (D) must be able to satisfy the above various conditions.

2 to 3c show the most general configuration of such a door release (R).

The conventional door release (R) is composed of upper and lower bodies (1a) (1b) hooks for locking the hook (H) of the fire door (D) in the interior of the case (1) having a hook insertion opening (1c) on one side The holder 2 and the holder lockers 5 for fixing the hook holder 2 in the locked state of the hook H are hinged and are elastically biased in a direction facing each other. A solenoid 6 is provided on the case 1b to release the lock of the holder locker 5 in response to the signal of the fire detector.

The hook holder 2 has a hook-shaped first holder 3 having a hook catching groove 3a on which the hook H is fitted, and a hooking jaw 4a at one end thereof. 3) and an L-shaped second holder 4 connected to the lower part so as to be relatively rotatable.

The first holder 3 engages the locking protrusion 5a of the holder locker 5 to be described later when the first holder 3 is selectively rotated on the outer circumference of the head portion 3b forming the hook locking groove 3a. It has a forced release surface 3c for forcibly detaching from the engaging groove 4a of the 2nd holder 4. As shown in FIG.

The first and second holders 3 and 4 of the hook holder 2 have lugs 3d and 4b corresponding to each other at the other end thereof, and the adjusting screw 7 has a compression coil spring 7a. Through the lug (3d) of the first holder (3) and then screwed to the lug (4b) of the second holder (4) is integrally connected to each other by the elasticity of the compression coil spring (7a) It is supposed to rotate together.

The holder locker (5) has a locking projection (5a) fitted to the hooking jaw (4a) of the hook holder (2) and the second holder (4) on one side, and is connected to the shaft (6a) of the solenoid (6) on the other side. Has a release pin 5b.

Accordingly, when the hook (H) enters the hook insertion hole (1c) by opening the fire door (D) as shown in Figure 3a, the hook holder (2) is rotated in the opposite direction of elasticity, the hook (H) as shown in Figure 3b The holder locker 5, which is fitted in the locking groove 3a and restrained on the forced release surface 3c of the head portion 3b of the first holder 3, is rotated in the elastic direction so that the locking projection 5a is removed. The holder locker 5 is rotated in the opposite direction of elasticity by the release pin 5b connected to the solenoid 6 in case of fire. When the restraint of (4) is released, the hook holder 2 rotates in the elastic direction and returns to the initial state as shown in Fig. 3A, thereby releasing the restraint of the fire door D.

When the fire door D is to be closed during non-fire, when the fire door D is pulled with a predetermined force in the state of FIG. 3B, only the first holder 3 of the hook holder 2 as shown in FIG. 3C has its elastic direction. The fire door D is closed by turning slightly so that the forced release surface 3c of the head portion 3b disengages the locking projection 5a of the holder locker 5 from the locking projection 4a of the second holder 4. It becomes possible.

The remaining symbols 2a and 5c are torsion springs for elastically biasing the hook holder 2 and the holder locker 5, 8 is a cover covering the solenoid 6, and 9a and 9b cover the door release to the wall. Bracket for attaching.

By the way, in the conventional door release device for fire doors, the hook holder 2 and the holder locker 5 are hinge-assembled to the case 1 and face each other by the torsion springs 2a and 5c. Since the structure is configured to restrain the fire door D by being elastically biased and release it by the solenoid 6, there is a problem that the restraint of the fire door D is easily released when an external shock is applied.

That is, the hook holder 2 which locks the hook H of the fire door D, and the holder locker 5 which locks the hook holder 2 in the locked state are supported by the elasticity of the torsion spring 2, 5c. By the rotational operation, both of which are rotated in the opposite direction of elasticity in the open state of the fire door D, so that the restrained state is maintained only by the locking protrusion 5a, which impacts the fire door D or the wall W from the outside. In this case, the hook holder 2 and the holder locker 5 are vibrated about each hinge by the strong impact force acting momentarily, and the restoration elasticity of each torsion spring 2a, 5c is complex. When the lock holder 2 is released from the restraint, the fire door D is easily closed even in an unfired state.

The present invention was devised in view of the above-described conventional problems, and it is possible to close the fire door forcibly even if it is necessary even in the event of fire, while ensuring that the restraint of the fire door is released by an impact from the outside, thereby ensuring that the fire door is not released. It is an object of the present invention to provide a door release device for a fire door that can stably maintain the open state of the fire door, and can quickly release the restraint of the fire door in case of fire.

In order to achieve the above object, the door release device for a fire door according to the present invention comprises: a case having a hook insertion opening through which a hook provided at the fire door enters and exits; A hinge assembly inside the case to lock and release the hook of the fire door by the forward and reverse rotation, and a hook holder having a driven gear on one side of the outer periphery; An interlock shaft that is rotatably supported by the case with a driving gear engaged with the driven gear of the hook holder; A release motor having a reduction gear having a deceleration force greater than a closing force acting on the fire door, so as to be electrically coupled with the interlock shaft, and the hook holder being driven in a direction to release the locking of the hook according to an external fire detection signal; It is characterized by.

According to one preferred feature of the present invention, it is provided with a rotation limiting means for limiting the amount of rotation of the release motor when driving the release motor to prevent damage to the release motor.

According to another preferred feature of the invention, it further comprises an impact preventing means for preventing the impact damage of the reducer during the external impact in the state that the fire door is locked in the open state.

According to the present invention, the hook holder for locking the hook of the fire door and the reducer of the interlock shaft and the release motor are firmly coupled by the gear bite to secure the fire door in the open state by the deceleration force of the reducer, in case of fire Of course, it is possible to simply close the fire door when necessary in the case of non-fire, and in particular, it is possible to reliably prevent the restriction of the fire door is released by the impact from the outside, unlike the prior art.

Accordingly, it is possible to keep the door open stably regardless of the big and small impacts that can be frequently applied in the open state, and to prevent the spread of fire by quickly releasing the restraint of the fire door in case of fire. .

Therefore, this invention has the effect which contributes greatly to the improvement of reliability, safety, etc. of a fire door.

Such specific features and other advantages of the present invention will become more apparent from the following description of the preferred embodiments with reference to the accompanying drawings.

4 to 7 show a first embodiment of the door release device for a fire door according to the present invention, and the parts not shown will be described with reference to FIG.

The door release device (R) for the fire door according to the present invention includes a case (10), a hook holder (20) for hinge assembly inside the case (10) to lock the hook (H) of the fire door (D), and a case ( 10) the hinge assembly therein is coupled to the hook shaft 20 through the linkage shaft 30 and the interlock shaft 30 according to the fire detection signal from the outside to transfer the power of the release motor 40 to the hook holder 20. It comprises a release motor 40 for releasing the locking.

The case 10 is divided into lower and upper bodies 11 and 12 coupled to each other, and has a hook insertion hole 13 through which the hook H of the fire door D enters and exits on one side. A hinge shaft 14 is provided to which the hook holder 20 is rotatably assembled to one side of the hook insertion hole 13 in the case 10.

One side of the upper body 12 is formed with an assembly hole 15 through which the upper end of the interlock shaft 30 penetrates, and a cover 16 that shields the exposure of the release motor 40 on the upper body 12. Is installed.

Hook holder 20 is configured in the form of a hook (hook) having a hook catching groove 21 to be hooked to the hook (H) of the fire door (D), approximately the middle portion is coupled to the hinge shaft (14). A driven gear 23 meshing with the drive gear 31 of the interlocking shaft 30 to be described later is formed on the outer circumference of the head 22 forming the hook locking groove 21.

Hook hook groove 21 is formed so as to overlap the hook insertion hole 13 of the case 10, and thus the head 22 is positioned to prevent the separation of the hook (H) across the hook insertion hole (13).

The interlock shaft 30 is rotatably supported at the lower end by the lower body 11, and the upper end thereof protrudes a predetermined length upward through the assembling hole 15 of the upper body 12.

The interlock shaft 30 has a drive gear 31, which is located inside the case 10 and engaged with the driven gear 23 of the hook holder 20, in the middle of the body, and above the upper body 12. It has a driven bevel gear 32 integrally engaged with the driven bevel gear 42 of the release motor 40 to be described later in the upper end.

The release motor 40 includes a speed reducer 41 for lowering the speed of the rotating shaft at a constant rate, which is fixed when the hook holder 20 locks the hook H when the fire door D is opened. This is to maintain the fire door (D) in the open state irrespective of the return force of the door closer (C).

That is, the rotation shaft of the release motor 40 does not exert a force greater than the return force of the door closer C by the reduction ratio of the reduction gear 41 composed of a plurality of gears (gear rows) continuously engaged with each other. In this case, by setting the reduction ratio so that it does not rotate naturally, the fire door D can be kept in the open state despite the return force of the door closer C unless the release motor 40 is driven by the power source. will be.

Here, when the force greater than the return force of the door closer (C) in the closing direction of the fire door (D), more specifically the external force greater than the deceleration ratio of the release motor 40, reducer 41 is released motor (40). Even if the) is not driven, the fire door D can be forced to close.

Therefore, the reduction ratio of the speed reducer 41 is set to be larger than the closing force (return force) acting on the fire door D by the door closer C, but is set to such an extent that a person can be forcibly closed if necessary. desirable.

The output shaft 41a of the reducer 41 is provided with a driven bevel gear 42 that meshes with the driven bevel gear 32 of the interlock shaft 30.

On the other hand, the release motor 40 is automatically powered by the external fire detection signal is driven by the bar, after the hook holder 20 is rotated by a predetermined angle required to release the hook (H) release motor 40 To protect the power, the power applied to it should be cut off.

To this end, the present invention is provided with a rotation limit means 50 for shutting off the power of the release motor 40 in the event of fire.

The rotation limit means 50 may be configured in various forms. For example, a limit lever integrally attached to the output shaft 41a of the reduction gear 41 and pivoted together as shown in FIG. The limit switch 51 is attached to the speed reducer 41 and cuts off the power of the release motor 40 according to the contact with the limit lever 53 when the limit lever 53 is rotated forward (a hook release direction). Is made of.

In addition, the stopper restricts excessive reverse rotation of the hook holder 20 (locking direction of the hook) by contacting the limit lever 53 during the reverse rotation of the limit lever 53 at a predetermined angle away from the limit switch 51. : 52 may be provided together, such a stopper 52 is not necessarily required.

The remaining reference numerals 17 and 18 are brackets attached to the front and rear surfaces of the case 10 to fix the door release R to a housing (not shown) built in the wall W. It is a slot for access of the hook H.

Operation of the first embodiment of the door release device for a fire door according to the present invention configured as described above is as follows.

First, FIG. 6A illustrates a state in which the fire door D is closed, and the hook holder 20 is rotated slightly in the clockwise direction in the drawing so that the head 22 opens the hook insertion hole 13 of the case 10. At this time, the limit lever 53 of the rotation limiting means 50 is separated from the stopper 52 as shown by the virtual line in FIG. 7 so that one end thereof is in contact with the limit switch 51, and the power is cut off. to be.

In this state, when the fire door D is opened, the hook H provided on the outer surface enters into the hook insertion hole 13 of the case 10 and pushes the hook holder 20, thereby. The holder 20 is rotated counterclockwise.

Then, the head 22 of the hook holder 20 is shielded across the hook insertion hole 13 of the case 10, thereby fixing the hook H to the hook locking groove 21.

At this time, since the force applied to the opening of the fire door (D) is greater than the return force of the door closer (C), the release motor 40 and the reduction gear 41 is forcibly rotated in the reverse direction (the reverse direction of the release), rotation limit means ( The limit lever 53 of 50 is rotated counterclockwise to be separated from the limit switch 51.

On the other hand, even if the limit lever 53 is separated from the limit switch 51 as described above, since it is non-fire, power is cut off by an external fire detector (not shown), and the release motor 40 is not driven.

After the fire door D is opened and the hook H is locked by the hook holder 20 as described above, the reduction ratio of the reduction gear 41 of the release motor 40 is greater than the return force of the door closer C. Since the fire door D is largely set, the fire door D is not automatically closed and is kept open until the fire door D is forcibly closed by a force of a certain size or more.

In particular, the door release device (R) of the present invention, unlike the conventional lock which is locked by the elasticity of the torsion spring, the hook holder 20, the linkage shaft 30 and the reducer 41 are of course firmly coupled to the gear bite. Since the deceleration ratio of the release motor 40 and the reducer 41 is set to be larger than the return force of the door closer C, even if a large physical shock is applied while the fire door D is opened, The flow hardly occurs and is fixed by the reducer 41 in a stable state so that the locking of the hook H is not abnormally released.

Next, when a fire occurs in a state in which the fire door D is opened, power is applied to the release motor 40 by a signal of a fire detector.

Then, the release motor 40 is driven in the forward direction (hook locking release direction), and thus the interlock shaft 30 connected to the output shaft 41a of the reduction gear 41 by the driven and driven bevel gears 32 and 42 is At the same time, the hook holder 20 is rotated clockwise by the driven gear 23 engaged with the driving gear 31 thereof.

At this time, the limit lever 53 fixed to the output shaft 41a of the reduction gear 41 also rotates, and when the limit lever 53 comes into contact with the limit switch 51, the power applied to the release motor 40 is applied. This blockage stops driving of the release motor 40.

When the hook holder 20 rotates in the clockwise direction, the head 22 is released from the hook insertion hole 13 of the case 10 to release the blocking of the hook insertion hole 13, and accordingly the hook holder 20 Hook of the hook (H) was caught in the hooking groove 21 of the release is released so that the hook (H) can come out of the case (10).

Then the fire door (D) is automatically closed by rotating to the initial position by the return force of the door closer (C).

On the other hand, when the fire door (D) is fixed in the open state even when the non-fire is pulled with a predetermined force (greater than the deceleration force of the reducer), the hook holder 20 in the situation that the power is not applied to the release motor 40 ) Can be forcibly rotated in the unlocking direction, so that the fire door (D) can be easily opened and closed if necessary even in the case of non-fire.

8 to 9D show a second embodiment of the door release device R for the fire door according to the present invention, which is used to prevent damage of the reducer 41 during impact in the above-described configuration of the first embodiment. The shock preventing means 60 for preventing is further configured. Therefore, for the remaining parts except for the impact preventing means 60 has the same configuration and operation and effect as the above-described first embodiment will not be repeated for convenience.

The shock preventing means 60 of this second embodiment is a holding lever 61 which is integrally connected to the hook holder 20 and rotatably installed on the same hinge shaft 14, and the hook holder. The locker (64) and the hook holder (20) for locking the holding lever (61) when the lock (20) of the fire door (D) locks the hook (H). And an unlock key 26 to unlock the locker 64 upon release.

The holding lever 61 is formed in an L shape and overlaps the lower portion of the hook holder 20. The holding lever 61 has a locking groove 62 in which the rocker 64 is elastically fitted at one end portion corresponding to the driven gear 23 of the hook holder 20.

The holding lever 61 is provided with lugs 63 and 25 perpendicularly to the other end thereof and the corresponding end of the hook holder 20, and the screw 66 is hooked through the compression coil spring 67. FIG. It penetrates the lug 25 of the holder 20 and then is screwed to the lug 63 of the holding lever 61 so as to be elastically connected to the hook holder 20 to rotate together with the hook holder 20 as well as to counterpart. Rotation is also possible.

That is, the compression coil spring 67 is located between the lug 25 of the hook holder 20 and the head of the screw 66 so that the two are integrally overlapped by the elastic force, and the compression coil spring is connected. When a force greater than the elasticity of (67) is applied to each other can be rotated with respect to each other, by the tightening and loosening of the screw 66 can also control the mutual coupling force.

The rocker 64 may be independently hinged to the case 10, but is preferably rotatably coupled to the interlock shaft 30 to be elastically held toward the holding lever 61 by the torsion spring 65 as shown. It is biased (elastic bias).

The rocker 64 has a thickness greater than that of the holding lever 61 so that the release key 26 described later can be contacted with the holding lever 61.

The release key 26 is formed to protrude from the lower surface of the head 22 of the hook holder 20. Of course, although the hook holder 20 may be formed over the entire surface of the hook holder H, the locker 64 may be removed from the locking groove 62 of the holding lever 61 when unlocking the hook H. Likewise, the hook holder 20 is provided to protrude only below the head 22, which may be any.

Accordingly, one end of the holding lever 61 corresponding to the release key 26 is formed stepped so that the release key 26 protruding from the lower surface of the hook holder 20 may be located.

Release key 26 is bent in the outer peripheral surface approximately convex in the middle portion to release the locker 64 to be released from the locking groove 62 of the holding lever 61 when the hook holder 20 is pulled in the release direction Only the front end portion thereof has a configuration in contact with the rocker 64 during the rotation.

Next, operation of the second embodiment of the door release device for fire doors according to the present invention configured as described above will be described.

First, the second embodiment of the door release device for fire doors of the present invention is the same as the above-described first embodiment except that the holding lever 61 rotates together with the hook holder 20 during the locking and releasing operation of the hook H. It's quite the same. However, in this case, the operation of the impact preventing means 60 is distinguished from the first embodiment in that the parallel operation, the following will mainly describe the operation of the impact preventing means (60).

9A shows that the fire door D is not opened, in which case the holding lever 61 is slightly rotated clockwise in the drawing together with the hook holder 20. Accordingly, the locker 64 has a release key ( It is pushed in the direction opposite to the elasticity by 26 and is separated from the locking groove 62 of the holding lever 61.

In this state, when the hook (H) enters the hook insertion hole (13) of the case (10) by the opening of the fire door (D) and the hook holder (20) rotates counterclockwise, the holding lever (61) is also the hook holder. It is rotated with (20). Accordingly, as shown in FIG. 9B, the hook H is inserted into the hook engaging groove 21 of the hook holder 20 and locked, and as shown in FIG. 9D, the locker 64 is the head of the hook holder 20. The counter-clockwise rotation is performed by restoring elasticity of the torsion spring 65, while being restrained by the release key 26 provided in the reference numeral 22 so as to be elastically fitted to the locking groove 62 of the holding lever 61.

Then, since the holding lever 61 is firmly fixed in the locked state of the hook H, even if a strong shock is applied from the outside, the shock transmitted to the reducer 41 of the release motor 40 is transmitted to the holding lever 61 and the rocker. 64 effectively blocks.

That is, the door release device (R) for the fire door of the present invention is connected to the hook holder (20) for locking the hook (H) and the reducer (41) of the interlock shaft (30) and the release motor (40) by a gear bite Although the fire door D is kept open by the 41, there is a risk of damage to the reducer 41 in the event of an impact from the outside. In the second embodiment, the hook holder 20 is compressed by the compression coil spring 67. Since the holding lever 61 is integrally coupled to the rocker 64 is fixed to the rocker 64, even if an impact is applied, the holding lever 61 and the rocker 64 are properly blocked to prevent damage to the reducer 41.

On the other hand, when power is applied to the release motor 40 due to the fire, and the release motor 40 is rotated in the forward direction (locking release direction of the hook), the holding lever (locked to the locker 64 as shown in Figure 9c at the beginning of release) 61 is rotated slightly in the clockwise direction while deforming the compression coil spring 67 only the hook holder 20 in the state in which it remains.

Then, the release key 26 provided in the hook holder 20 pushes the rocker 64 in the opposite direction of elasticity as shown by the virtual line in FIG. Thus, the holding lever 61 is rotated clockwise together with the hook holder 20 to escape the restraint from the rocker 64. At this time, when the locker 64 exits from the catching groove 62, the holding lever 61 is rapidly rotated by the restoring elasticity of the compression coil spring 67, and again overlaps with the hook holder 20, and then rotates together.

Further, even when the fire door D is manually closed by necessity during non-fire, it is operated in the same manner as the unlocking operation in the above-described fire.

1 is a cross-sectional view schematically showing a state in which a fire door automatic closing device according to the present invention is attached to a fire door;

2 is an exploded perspective view showing a conventional door release device for a fire door;

3a to 3c are plan views showing the operation of the conventional door release device for fire doors,

Figure 4 is an exploded perspective view showing a first embodiment of the door release device for a fire door according to the present invention;

Figure 5 is a perspective view of the excerpts showing the combined state of Figure 4,

6A and 6B are plan views showing the operation of the first embodiment of the door release device for a fire door according to the present invention;

7 is a side view schematically showing a rotation limiting means of the door release device of the present invention;

8 is an exploded perspective view showing a second embodiment of a door release device for a fire door according to the present invention;

9A to 9D are plan views showing the operation of the second embodiment of the door release device of the present invention.

10: Case 13: Hook Inlet

14: hinge axis 15: assembly hole

20: hook holder 21: hook hook groove

22: Head 23: Driven Gear

25: Lug 26: Release Key

30: linkage shaft 31: drive gear

32: driven bevel gear 40: release motor

41: reducer 41a: output shaft

42: original bevel gear 50: rotation limit means

51: limit switch 53: limit lever

60: impact preventing means 61: holding lever

62: locking groove 63: lug

64: rocker 65: torsion spring

66: screw 67: compression coil spring

D: Fire Door H: Hook

Claims

It is a door release device which fixes the fire door installed in the building in the open state and automatically releases the fire door by the smoke detection signal in case of fire.

A case having a hook insertion opening through which the hook provided at the fire door enters and exits;

A hinge holder assembled to the inside of the case to lock and release the hook of the fire door by forward and reverse rotation, and having a driven gear on one side of the outer circumference;

An interlock shaft that is rotatably supported by the case with a driving gear engaged with the driven gear of the hook holder;

A release motor having a reduction gear having a deceleration force greater than a closing force acting on the fire door, so as to be electrically coupled to the interlock shaft, and driven in a direction in which the hook holder releases the locking of the hook according to an external fire detection signal; Door release device for a fire door comprising a.

The fire door release device according to claim 1, further comprising rotation limiting means for limiting the amount of rotation of the release motor when the release motor is driven.

The limit switch of claim 2, wherein the rotation limiting means is a limit switch that cuts off the power applied to the release motor by contacting the limit lever fixed to the output shaft of the reducer and the limit lever rotated by the release motor. Door release device for a fire door, characterized in that made.

The fire door according to any one of claims 1 to 3, further comprising an impact preventing means for preventing an impact damage of the speed reducer during an external impact when the fire door is locked in an open state. Door release device.

The method of claim 4, wherein the impact preventing means,

A holding lever overlapping a lower portion of the hook holder and being coaxially hinged with the hook holder, integrally coupled with the hook holder by elastic means, interlocking with each other, and having a locking groove at one end thereof;

A locker rotatably assembled to the interlock shaft and elastically fitted to the locking groove of the holding lever in a locked state of the hook;

And a release key formed at a lower surface of the head of the hook holder to release the locker from the locking groove of the holding lever during the initial rotation of the hook holder.

The method of claim 5, wherein the elastic means,

A screw is vertically formed to overlap each other end of the hook holder and the holding lever so as to vertically pass through the lug of the hook holder, and then screwed to the lug of the holding lever, and the head of the screw and the lug of the hook holder A door release device for a fire door, interposed therebetween, comprising a compression coil spring for elastically closely contacting a reholder to a holding lever.