KR101876743B1 - Electric damper with mechanical micro air volume control function - Google Patents

Abstract

The present invention provides an electric damper with a mechanical fine air volume control function, capable of improving air conditioning efficiency through improvement of proper air flow volume distribution. According to the present invention, either or both of sub blocking plates comprise: a lower member coupled to a blocking plate by a fixing pin; and an upper member coupled to the lower member by a rotational pin. A second torsion spring to press the upper member towards the blocking plate is installed in the rotational pin, and a supporting protrusion protruding towards the blocking plate and a rotational angle adjustment piece covering the outside of the lower member are formed on both sides of the upper member.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electric damper having a mechanical micro-

The present invention relates to an electric damper for controlling the amount of air flow inside a duct by further comprising an auxiliary blocking plate mechanically operated on a blocking plate in a multi-stage electric damper, more specifically, The present invention provides an electric damper having a mechanical micro-volume control function capable of enhancing the efficiency of cooling and heating through reduction of noise of an exhaust noise and improvement of distribution of a proper air volume, will be.

Generally, an electric damper is a component installed on a duct of an air system to control the amount of air flow.

The electric damper has various configurations. As a representative example, a "electric damper having an air volume control function" of Korean Registered Patent Application No. B1-1505642 (Feb. 25, 2015) filed by the present inventor has been proposed The air conditioner according to the present invention is characterized in that an air blower is installed at the upper end of a flue connected to a hood of a multi-unit house, and the open angle between the flue and the hood is controlled to be multi- Is controlled by a control unit electrically connected to a circuit board by a first switch assembly operation, the electric damper comprising: The control unit is further provided with a wind speed sensor installed inside the discharge end of the electric damper to sense the discharge wind pressure and notify the sensed value to the microcomputer of the control unit. The amount of discharge can be reduced by opening the blocking plate to a large extent or by opening the blocking plate to a small size to reduce the amount of discharge, or the microcomputer provided on the circuit board of the control unit is provided with an operation signal of the electric damper So that the fan control means is electrically connected to the fan so that the fan operates simultaneously when the electric damper is operated. And when the signal of the first switch assembly is present, the microcomputer drives the electric damper several seconds after the fan is driven.

Another example is an "electric damper" of the Korean Utility Model Registration Utility (Y1) 20-0477580 (Jul. 2015.06.06), which is configured to open and close an exhaust duct for taking out the inside air connected to the ventilator to the outside The electric damper according to claim 1, further comprising a tubular body connected to the exhaust duct, the tubular body being formed by connecting an intake surface formed on a blowing surface of the blower by the blower and a blower surface blowing the blower A body portion having an inclined surface which is inclined from an upper portion to a lower portion at a position spaced apart from the intake surface by a predetermined distance in the direction of the outflow surface and is formed so as to protrude from the inner circumferential surface to the central portion; A damper lid installed in a hinge-coupled manner, and a damper cover provided between the inclined surface and the intake surface to penetrate the body portion A motor having a motor rotation shaft installed on the outside of the body portion and a hinge bar which is coupled to the motor rotation shaft and rotates while passing through the through hole and has a hinge bar for applying a force to the damper lid, And that the inclined surface and the damper lid are coupled with a magnetic force in a state in which the ventilator is not operated.

In the conventional electric damper, when the damper lid is operated, the actuating force of the damper lid is rotated by the driving force of the motor at a predetermined angle. However, in such a case, there is a problem in that the circuit configuration for controlling the amount of emission when the excessive suction force is generated at the discharge side is complicated, it is difficult to expect sensitive operation, and exhaust noise is generated at the time of discharge, There is a demand for an electric damper of a new construction capable of solving the same problem.

Therefore, the inventor of the present invention has solved the problem that the conventional electric dampers have a configuration in which the air flow rate is controlled by rotating the blocking plate only in multi-stages, so that the air flow rate changes according to the suction force on the discharge side in a state in which the blocking plate is rotated (B1) 10-1702268 (Feb. 27, 2017), which is incorporated herein by reference in its entirety, discloses an electric damper having a mechanical airflow control function.

In the above-described prior art, a shutoff plate is installed inside the main body so as to control the flow of air, and a drive shaft horizontally disposed on the shutoff plate is drawn out to the outside of the main body. The control damper is configured to rotate the shut-off plate by engaging a drive motor rotating in the forward and reverse directions controlled by the multi-stage rotation by the means. The auxiliary blocking plate is structured such that an air inflow space is formed between the blocking plate and the lower blocking plate is axially coupled to the fixing pin provided on the blocking plate, And the auxiliary blocking plate is urged toward the blocking plate by the elastic force of the torsion spring having both ends thereof supported by the blocking plate and the auxiliary blocking plate. The air inlet space is configured to face the suction port when the blocking plate is partially open, The auxiliary blocking plate is configured such that rotation of the auxiliary blocking plate is restricted by a stopper provided on the blocking plate.

However, in the case of the above-described auxiliary blocking plate, there is a problem that the blocking plate is not operated smoothly in a state where the blocking plate is slightly opened at the first stage, and a technique for operating it sensitively to the air flow has been demanded.

KR 101505642 B1 2015.03.25. KR 200477580 Y1 2015.07.06. KR 101702268 B1 2017.02.02.

Therefore, the inventor of the present invention has researched a problem that the auxiliary blocking plate, which mechanically operates on the blocking plate in the conventional multi-stage electric damper, does not smoothly rotate the auxiliary blocking plate according to the weak air volume .

That is, in the present invention, the auxiliary blocking plate is mechanically operated at one side or both sides of the blocking plate electrically opened and closed, and the auxiliary blocking plate is divided into upper and lower two stages, Which is capable of improving the efficiency of cooling and heating through reduction of noise of the ventilation noise as well as proper distribution of the airflow distribution by allowing the auxiliary member to be rotated smoothly, The present invention has been completed based on the technical problem of the invention.

According to an aspect of the present invention, in the present invention, a shutoff plate is installed in a first duct to control the flow of air, a drive shaft horizontally disposed on a shutoff plate is drawn out to the outside of the main body, The control panel is rotatable by a control means to rotate the control panel in a counterclockwise direction, and the control panel is rotatable, and the control panel further includes an auxiliary blocking plate mechanically operated on one side or both sides thereof, The blocking plate is configured such that an air inflow space is formed between the blocking plate and the lower end is axially coupled to the fixing pin provided on the blocking plate and the auxiliary blocking plate is blocked by the elastic force of the first torsion spring, And the air inflow space is configured to face the suction port when the blocking plate is partially opened , The sub-blocking plate is in an electric damper that has a mechanical micro air volume control function is configured to be rotated is limited by the stopper installed on the shield plate;

The one or both of the auxiliary blocking plates may include a lower member coupled to the blocking plate with a fixing pin; A lower member coupled to the lower member by a pivot pin; A second torsion spring for pressing the upper member toward the blocking plate is provided on the pivot pin; The support member is formed at both sides of the upper member with protruding protrusions protruding toward the shut-off plate, and a rotation angle adjusting piece is formed to cover the outer side of the lower member.

Second, the second torsion spring has a weaker elastic force than the first torsion spring.

Thirdly, the stopper is provided with an elastic support member to elastically support the auxiliary blocking plate.

Fourthly, the elastic support member adjusts the elastic force of the upper member constituting the auxiliary blocking plate on the basis of the adjustment indication protrusions having different heights formed on the side of the elastic support member, so that the elastic force of the upper member can be controlled .

In the case of using the electric damper having the mechanical micro air volume control function provided in the present invention, when the suction force from the discharge port side is strengthened in a state that the blocking plate is partially opened, the auxiliary blocking plate rotates to reduce the discharge space between the main body and the blocking plate, The air inflow space formed between the shielding plate and the auxiliary shielding plate is directed toward the discharge port so that the airflow is not disturbed.

Particularly, in the present invention, the auxiliary shielding plate is divided into the lower member and the upper member, and the upper member, which constitutes the auxiliary blocking plate, is sensitively rotated even when the upper member has a weak air volume, It can be controlled.

Therefore, when the present invention is used, it is possible to eliminate the problems caused by over discharge of air through the improvement of the proper airflow distribution, drastically reduce the noise generated thereby, and prevent the discharge of the room air, It is possible to expect a great effect.

1 is an external perspective view showing a preferred embodiment of an electric damper having a mechanical micro air volume control function provided by the present invention.
FIG. 2 is a perspective view showing an example of a blocking plate and an auxiliary blocking plate applied to an electric damper having a mechanical airflow control function of the present invention. FIG.
Fig. 3 is an exploded perspective view of Fig.
4 is a cross-
5 is a cross-sectional view showing a state in which another embodiment of the elastic support strip applicable to the present invention is applied
6 is a cross-sectional view schematically showing various embodiments in which an auxiliary blocking plate is applied to a blocking plate in the present invention
7 is a cross-sectional view of a state in which the auxiliary blocking plate is operated in a state in which the blocking plate applied to the electric damper having the function of adjusting the mechanical micro air flow rate is partially opened;
8 is a cross-sectional view showing a state in which a shut-off plate applied to an electric damper having a mechanical micro-airflow control function is fully opened and forced or exhausted from the intake port side
Fig. 9 is an example of application of the electric damper having the mechanical micro air volume control function provided in the present invention to a facility for forced exhaust or power exhaustion by a suction force in a loop fan

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of an electric damper having a mechanical micro air volume control function provided by the present invention will be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external perspective view showing a preferred embodiment of an electric damper having a mechanical micro air flow rate control function according to the present invention; FIG.

The outer appearance of the electric damper 1 having the mechanical micro air volume control function provided in the present invention is the same as that of the conventional art. The intake dam 3 and the discharge mouth (not shown) are connected to both sides of the cylindrical body 2, The bracket 5 is provided on the outer side of the duct 100 and the case 6 is provided on the bracket 5 so that air can be flowed from the suction port 3 to the discharge port 4, Is assembled.

A drive motor 7 including a speed reducer and a circuit board 8 including a rotation control means are fixed to the bracket 5 inside the case 6, The blocking plate 10 is installed in a state of being coupled to the driving shaft 11 so that the blocking plate 10 is rotated forward or backward by an electric signal and the blocking plate 10 is provided with an auxiliary blocking plate (12).

FIG. 2 is a perspective view illustrating a blocking plate and an auxiliary blocking plate applied to an electric damper having a mechanical airflow control function according to the present invention, FIG. 3 is an exploded perspective view of FIG. 2, and FIG. 4 is a sectional view of FIG. will be.

The electric damper 1 having a mechanical micro air flow rate control function provided in the present invention is disposed inside the main body 2 as shown in the drawing and has a drive shaft 11 coupled to the main body 2 at a right angle to the air flow direction, In the state of being coupled to the bracket 5 by means of the rotation control means provided on the circuit board 8 when rotated by the power of the constant-speed rotating drive motor 7 mounted on the bracket 5, The configuration of the auxiliary blocking plate 12 provided on the blocking plate 10 for pivoting is actively improved.

The opening of the blocking plate 10 is in the range of 90 to 180 degrees, and any one of various configurations such as a method using a plurality of limit switches, an encode or volume switch, a method using a PCB integrated pattern method, . These configurations are well known in the art and are not shown in detail in the present invention.

The shielding plate 10 applied to the present invention is formed by bonding or inserting a shielding packing 10b made of a rubber material which is in contact with the inner surface of the body 2 to the edge side of the body 10a made of an iron plate or a synthetic resin plate, The shaft portion 10c in which the shaft 11 is inserted is formed symmetrically.

The body 10a constituting the blocking plate 10 is provided with the auxiliary blocking plate 12 so that when the suction force of the blocking plate 10 from the outlet port 4 is increased The discharge space A formed between the inner surface of the main body 2 and the blocking packing 10b is narrowed by the rotation of the auxiliary blocking plate 12 so as to obstruct the air flow so that the air flow can be discharged.

The auxiliary shielding plate 12 may be applied to one side or both sides of the shielding plate 10.

In the case of the construction in which the auxiliary shielding plate 12 is coupled to the shielding plate 10, an electric damper having a mechanical airflow control function of Korean Registered Patent Application No. B1-1 1022268 (Feb. In the present invention, the configuration of the auxiliary blocking plate 12 is further improved so that the phase member 14 constituting the auxiliary blocking plate 12 is sensitively rotated even in a weak air volume, So that the operation can be smoothly performed.

The auxiliary blocking plate 12 provided in the present invention is divided into the lower member 13 and the upper member 14 and a first pin coupling hole 13a is formed at the lower end of the lower member 13 A side plate 13b is formed on both sides so as to face the blocking plate 10 and an air inflow space 15 is formed between the auxiliary blocking plate 12 and the blocking plate 10, (13b) is formed of a triangular plate which gradually widens from the side of the first pin coupling hole (13a) formed at the lower end, and is made of thin plate of aluminum or synthetic resin so as to be sensitive to the air flow.

The engagement of the lower member 13 is performed by fixing the pin engagement piece 16 to the shield plate 10 below the shaft holding portion 10c formed at the center of the blocking plate 10, And the first pin coupling hole 13a formed on the lower side of the lower member 13 is passed through the fixing pin 17 and the stop pin 17 10 and the first torsion spring 18 having both ends thereof are grounded together so as to press the lower member 13 toward the blocking plate 10. [

A second pin coupling hole 13c is formed in the upper end of the lower member 13 and a pivot pin 19 is formed in the second pin coupling hole 13c. And a third pin coupling hole 14a formed at the lower end thereof is fitted so that the phase member 14 can be rotated about the pivot pin 19. [

At this time, the second torsion spring 20 is assembled together with the pivot pin 19 so that the upper member 14 is pressed toward the blocking plate 10. [

The upper member 14 is formed with supporting protrusions 14b projecting toward the blocking plate 10 at both sides so that the air inflow space 15 can be formed between the blocking plate 10 and the upper member 14 And a rotation angle adjusting piece 14c is formed on the lower side of the upper member 14 so as to cover the outer side of the lower member 13. [

The rotation angle adjusting piece 14c is spaced apart from the lower member 13 when the upper member 14 and the lower member 13 are positioned in equilibrium. When the upper member 14 is rotated outwardly, And the lower member 13 is provided with a wind pressure so as to provide the function of allowing the lower member 13 to be turned outwardly together with the upper member 14. [

On the other hand, the first torsion spring 18 coupled to the fixing pin 17 provides stronger force than the elastic force of the second torsion spring 20 coupled to the pivot pin 19. This is because the upper member 14 supported by the second torsion spring 20 having a weak elastic force is sensitive to the first torsion spring 18 having a strong elastic force in a state where the upper member 14 is first rotated And the operation of the first lowering member 13 to be supported can be sequentially performed.

In the meantime, the present invention includes a stopper 21 for preventing the auxiliary blocking plate 12 from being excessively rotated by the air flow.

The stopper 21 is located between the pinch portion 10c to which the drive shaft 11 is coupled and the first pin engagement hole 13a of the lower member 13. The stopper 21 is fixed to both sides of the support pin 21a, The fixing piece 21b is fixed to the body 10a constituting the blocking plate 10 from the outside of the auxiliary blocking plate 12 so that the auxiliary blocking plate 12 is fixed to the fixing pin 17 So that it can be stopped by the support base 21a of the stopper 21 when making a call arc around the center.

On the other hand, the stopper 21 is provided with a structure in which the elastic supporter 22 is further coupled to the auxiliary blocking plate 12 as a means for preventing the auxiliary blocking plate 12 from being excessively collided with the stopper 21 .

The elastic supporter 22 is configured such that one end thereof is fixed to the supporter 21a and the other end thereof is formed into a hook shape toward the upper end of the auxiliary blocking plate 12. [ In the present invention, an example is shown in which the elastic supporter 22 is fixed to the supporter 21a with a fixing screw 23.

FIG. 5 is a cross-sectional view showing a state in which another embodiment of the elastic support which can be applied to the present invention is applied.

5, the upper member 14 constituting the auxiliary blocking plate 12 is provided with adjustment indication protrusions 14d having different heights so as to be positioned on the side of the elastic support portion 22, The height of the elastic supporter 22 can be adjusted to adjust the elasticity of the upper member 14 when the upper member 14 is rotated.

That is, in the present invention, three adjustment display projections 14d are formed on the upper member 14 so that the lower member 13 is lower and gradually higher toward the upper end of the upper member 14. When the upper member 14 needs to be operated more sensitively in the course of the construction of the present invention, the adjustment display protrusion 14d, which is formed to be higher than the elastic support member 22, When the upper member 14 needs to be dullly operated, the tension may be adjusted so as to correspond to the lower adjustment control projection 14d by pressing the elastic support 22.

In the present invention, for example, the height of the three control display protrusions 14d is designed to have a tension corresponding to a wind pressure of 200 CMH, a medium height of 250 CMH, and a low height of 300 CMH. In this case, CMH refers to m³ / h in cubic meter per hour.

FIG. 6 is a sectional view schematically showing various embodiments in which an auxiliary blocking plate is applied to a blocking plate in the present invention.

The electric damper 1 having the mechanical micro air flow rate control function provided in the present invention can be applied to the case where the auxiliary shielding plate 12 is applied to one side of the shielding plate 10 as shown in FIG. The auxiliary blocking plate 12 can be applied.

The auxiliary shielding plate 12 may be divided into the upper member 14 and the lower member 13. The auxiliary shielding plate 12 may be selectively applied to one side of the shielding plate 10 or both sides of the shielding plate 10.

The operation of the electric damper 1 having the mechanical micro air flow rate adjusting function of the present invention constructed as described above in the duct 100 will be described.

FIG. 7 is a cross-sectional view illustrating a state in which the auxiliary blocking plate is operated in a state in which the blocking plate applied to the electric damper having the mechanical micro-airflow control function is partially opened.

According to the drawings, a part of the blocking plate 10 is opened, and in this state, a suction force is generated at the discharge port 4 side. At this time, the auxiliary blocking plate 12 is directed toward the suction port 3 which is opposite to the discharge port 4.

The operation of the auxiliary blocking plate 12 constituted by combining the lower member 13 and the upper member 14 is not performed and the suction amount is excessively generated when the suction amount is similar in a state where the blocking plate 10 is opened The upper member 14 is first rotated, and then the lower member 13 is secondarily rotated, so that the entire auxiliary blocking plate 12 is rotated.

That is, when the suction amount increases at the discharge port 4 side, the air flow passing through the discharge space A between the blocking packing 10b provided at the edge of the blocking plate 10 and the inner surface of the main body 2 increases, The air resistance supplied to the air inflow space 15 formed on the side of the upper member 14 constituting the auxiliary blocking plate 12 is strengthened so that the upper member 14 When the rotation angle adjusting piece 14c provided on the upper member 14 is first grounded around the rotation pin 19 and the lower member 13 is grounded, the lower member 13 together with the upper member 14 The air flow is gradually distant from the blocking plate 10 with the lower fixing pin 17 as the center, thereby reducing the amount of air discharged to the discharge port 4 by interfering with the air flow.

On the other hand, when the auxiliary blocking plate 12 configured by combining the lower member 13 and the upper member 14 is rotated in two stages as described above, the stopper 21 of the stopper 21, which controls the turning amount of the auxiliary blocking plate 12, 2 to 4, the elastic supporter 22 provided on the stopper 21 urges the auxiliary blocking plate 12 against the support base 21a So that it is possible to prevent breakage of the auxiliary blocking plate 12 and the like.

The auxiliary shielding plate 12 contacts the stopper 21 when the elastic shielding plate 22 contacts the auxiliary shielding plate 12 and the buffering is performed and a force stronger than the elastic force of the elastic support 22 acts. A little more rotation will reduce air emissions.

FIG. 8 is a cross-sectional view showing a state in which a blocking plate applied to an electric damper having a mechanical micro-air volume control function is fully opened and forced or exhausted from a suction port side.

According to the drawings, the blocking plate 10 is completely opened to be horizontal with respect to the direction of the air flow and is forcedly exhausted by the blower installed on the side of the suction port 3. At this time, the auxiliary blocking plate 12 formed by combining the lower member 13 and the upper member 14 is directed to the opposite side of the discharge port 4, so that the air flow is not hindered. That is, since the air inflow space 15 formed between the blocking plate 10 and the auxiliary blocking plate 12 is positioned in the direction opposite to the flow of air, the auxiliary blocking plate 12 is moved (10), the functionality of the auxiliary blocking plate (12) is lost.

When the blocking plate 10 is fully opened, unlike the case in which the blocking plate 10 is opened counterclockwise as shown in FIG. 9, it rotates in the clockwise direction so that the electric damper 1 is completely closed, .

This operation has the effect of shortening the operation time. In other words, if the blocking plate 10 is rotated counterclockwise by 30 degrees and the blocking plate 10 is fully opened counterclockwise, it is possible to rotate by 240 degrees. If the blocking plate 10 is rotated clockwise to be completely opened, So that it is possible to perform a quick operation.

(Example)

9 is a diagram illustrating an example of application of the electric damper having the mechanical micro air volume control function provided in the present invention to a facility for forced exhaust or power exhaust from a loop fan by a suction force.

A roof fan 300 is installed on the upper side of the vertical cylinder 200 and a duct 100 connected to the respective generations is connected to the vertical cylinder 200. The electric damper 1 and a blowing fan 400 for forced exhaust are installed. At this time, if there is no blowing fan in the range hood, it is power exhaust, and if there is a blowing fan, it means forced exhaust.

In this state, the suction force of the loop fan 300 is provided to the electric damper 1 on the side of the discharge port 4 when only a part of the electric damper 1 operating in multiple stages is partially opened in one or two stages. 9, when the suction force of the loop fan 300 is stronger than the exhaust amount set in the electric damper 1 and the discharge is performed, according to the present invention, And the air can be mechanically operated by the air movement, thereby reducing the amount of discharged air and enabling the discharge of the regular air amount.

10, when the forced ventilation is performed using the blowing fan 400, the blocking plate 10 of the electric damper 1 is fully opened. According to the present invention, the blocking plate 10, The air inflow space 15 formed between the first and second exhaust ports 12 is turned toward the exhaust port 4 so that the forced exhaust can be smoothly performed.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. Therefore, the scope of protection of the present invention should not be limited to the described embodiment, but should be determined by the equivalents as well as the claims that follow.

1: Electric damper (with mechanical air flow control function)
2: main body 3: inlet
4: Outlet 5: Bracket
6: Case 7: Driving motor
8: circuit board 10: shield plate
10a: Body 10b: Block packing
10c: shank portion 11: drive shaft
12: auxiliary blocking plate 13: lower member
13a: first pin coupling hole 13b: side plate
13c: second pin coupling member 14: upper member
14a: third pin coupling hole 14b: support projection
14c: rotation angle adjustment piece 14d: adjustment indication projection
15: air inlet space 16: pin coupling piece
17: Fixing pin 18: First torsion spring
19: Pivot pin 20: Second torsion spring
21: Stopper 21a: Support
21b: Fixing piece 22:
23: fixing screw 100: duct
200: Vertical year 300: Loop fan
400: Ventilation fan A discharge space

Claims (4)

A shield plate 10 is installed inside the main body 2 so as to control the flow of air and installed in the duct 100 to draw out the drive shaft 11 which is formed in the shield plate 10 to the outside of the main body 2 , The drive shaft (11) is coupled to a driving motor (7) rotating in the forward and reverse directions, the rotation of which is controlled by a rotation control means provided outside the main body (2) An auxiliary blocking plate 12 mechanically operated on one side or both sides of the plate 10 is further provided and the auxiliary blocking plate 12 is provided with an air inflow space 15 between the blocking plate 10 So that the lower end of the first torsion spring 18 is axially coupled to the fixing pin 17 provided on the shield plate 10 and the auxiliary torsion spring 18, The air inlet space 15 allows the blocking plate 12 to be pressed toward the blocking plate 10, And the auxiliary blocking plate 12 is arranged to face the inlet 3 so that the rotation of the auxiliary damper 12 is restricted by the stopper 21 installed on the blocking plate 10, ;
The one or both side auxiliary blocking plate 12 includes a lower member 13 coupled to the blocking plate 10 by a fixing pin 17; (14) coupled to the lower member (13) by a pivot pin (19);
A second torsion spring 20 for pressing the upper member 14 toward the shield plate 10 is installed on the pivot pin 19;
The support member 14b is formed at both sides of the upper member 14 and protrudes toward the blocking plate 10 and the rotation angle adjusting piece 14c is formed to cover the outer side of the lower member 13. [ A mechanical damper having a fine mechanical airflow control function.
The method of claim 1,
Wherein the second torsion spring (20) has a weaker elastic force than the first torsion spring (18).
The method of claim 1,
Wherein the elastic stopper (22) is provided on the stopper (21) to elastically support the auxiliary blocking plate (12).
The method of claim 3,
The elastic supporter 22 is provided on the upper member 14 constituting the auxiliary blocking plate 12 with reference to the adjustment indication protrusion 14d having different heights formed on the side of the elastic supporter 22 And the elastic force of the elastic member is adjusted to adjust an elastic force of the elastic member when the upper member (14) is rotated.

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