Lock mechanism and fitting

Abstract

To provide a lock mechanism having an air-tight case for covering an arm to be engaged with an interlocking bar, which is easily installed.SOLUTION: The lock mechanism of a fitting comprises a body part, an air-tight case for covering the body part, and a lever handle. The body part comprises an arm to be engaged with an interlocking bar installed on the frame body of the fitting. The air-tight case has a flange part disposed along the opening of the frame body. The air-tight case has a recess on the rear side of the flange part.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a locking mechanism.

Background Art

[0002] Conventionally, as a fitting such as a vertical sliding window or a horizontal sliding window, there is known one including a frame body, a shoji screen that can be opened and closed and stored in the frame body, an operation handle for opening and closing the shoji screen, and a locking mechanism for locking the shoji screen.

[0003] For example, as a locking mechanism, there is known one in which an interlocking member (interlocking bar) is moved via an operation handle so that the shoji screen can be locked by a locking pin and a locking piece (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When arranging the locking mechanism in the frame body, in order to ensure airtightness between the indoor and outdoor areas, conventionally, it has been considered to attach parts without gaps or attach an airtight sealant to the handle mounting opening on the indoor side. However, with the above methods, ensuring airtightness between the indoor and outdoor areas is not sufficient, and there is a problem that the user feels uncomfortable cold air when operating the locking mechanism with the handle. Therefore, it has been considered to cover the arm of the locking mechanism with an airtight case, but it has been physically difficult to engage the locking mechanism with the locking pin of the interlocking bar and attach the locking mechanism having the airtight case to the handle mounting opening.

[0006] The present disclosure has been made in view of the above, and is a locking mechanism having an airtight case that covers an arm engaged with an interlocking bar, and an object thereof is to provide a locking mechanism that can be easily attached.

Means for Solving the Problems

[0007] The present disclosure is a locking mechanism for a fitting, comprising a main body portion, an airtight case that covers the main body portion, and a handle lever. The main body portion includes an arm that engages with an interlocking bar provided on a frame of the fitting. The airtight case has a flange portion disposed along an opening of the frame, and a recess is formed on the back side of the flange portion of the airtight case. It relates to a locking mechanism.

Brief Description of the Drawings

[0008]

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MODE FOR CARRYING OUT THE INVENTION

[0009] FIGS. 1 and 2 are perspective views of a sliding window 100 as a fitting in which a sub-block 1a as a lock mechanism according to the present embodiment is used. FIG. 1 shows the closed state of the sliding window, and FIG. 2 shows the open state of the sliding window. In the following description, the prospective direction is the direction along the depth of the fitting, and in FIGS. 1 and 2, the front side may be described as the indoor side and the back side as the outdoor side. The plane along the prospective direction may be described as the prospective plane. The finding direction is the direction along the left and right of the window surface of the sliding window 100. The plane along the finding direction may be described as the finding plane.

[0010] The sliding window 100 has a frame body 11 arranged in an opening formed in a building (not shown), a shoji 12 housed inside the frame body 11, an operator handle 13, and a sub-block 1. Hereinafter, the sliding window 100 as a fitting will be described as a vertical sliding window. However, the lock mechanism of the present disclosure may be applied to a horizontal sliding window, or may be applied to a vertical opening window or a horizontal opening window.

[0011] The frame body 11 is configured by framing an upper frame, a lower frame, and a pair of vertical frames in a rectangular shape corresponding to the shape of the opening of the building. The frame body 11 and the shoji 12 may be made of a metal such as aluminum, or may be, for example, a resin composite sash in which the outdoor side is made of aluminum and the indoor side is made of resin, or may be made only of resin.

[0012] The shoji 12 is arranged inside the inner peripheral side of the frame body 11 so as to be openable and closable. The shoji 12 is configured by housing one or a plurality of glass plates 121 inside a frame body formed by framing an upper frame, a lower frame, and left and right vertical frames in a rectangular shape. A pair of stays 123 for supporting the opening and closing operation of the shoji 12 are provided above and below the shoji 12, respectively. The stays 123 are respectively bridged between the upper frame and the upper frame, and the lower frame and the lower frame.

[0013] The operator handle 13 is provided on the indoor-side finding surface of the lower frame of the frame body 11. The operator handle 13 is configured to be able to open and close the shoji 12 by transmitting a rotational force to the shoji 12 through an operation arm attached from the lower frame to the shoji 12.

[0014] The sub-block 1a as a lock mechanism is provided on the indoor-side prospective surface of the vertical frame of the frame body 11. As shown in FIG. 5, the sub-block 1a has an arm 50a that can engage with an engagement pin 143 provided on the interlocking bar 14. The sub-block 1a is configured to be able to slide the interlocking bar 14 in the vertical direction by transmitting the rotational force of the handle lever 2 to the interlocking bar 14 through the arm 50a.

[0015] The interlocking bar 14 is provided on the prospective surface on the outdoor side of the vertical frame of the frame body 11. As shown in FIG. 5, the interlocking bar 14 has an engaging portion 142 that can engage with an engaging portion 122 provided on the prospective surface on the side of the vertical frame of the shoji 12 that abuts against the frame body 11. In the state where the interlocking bar 14 is slid to the lowermost position, the engagement between the engaging portion 122 and the engaging portion 142 is released, and the shoji 12 is in the unlocked state. When the user operates the operator handle 13 and inserts the engaging pin of the engaging portion 122 into the engaging portion 142 and then operates the handle lever 2 to slide the interlocking bar 14 upward, the shoji 12 is completely pulled inward and the engaging portion 122 and the engaging portion 142 engage with each other, and the shoji 12 is in the locked state. A plurality of sets of the engaging portion 122 and the engaging portion 142 may be provided.

[0016] As shown in FIG. 3, the sub-block 1a has a handle lever 2, a handle pedestal 3, an airtight case 4 as an airtight structure, a main body portion 5a having an arm 50a, and a back plate 6.

[0017] The handle lever 2 is provided for the user of the sub-block 1a (hereinafter, may be simply described as "user") to transmit a rotational force to the arm 50a. As shown in FIG. 11, the handle lever 2 has a substantially L-shaped configuration and has a grip portion 21, a handle shaft 22, and a support portion 23. The grip portion 21 and the support portion 23 may be integrally formed of resin. The handle shaft 22 is a metal rod having a rectangular cross-sectional shape, and the tip end portion can engage with the shaft hole 501 of the arm 50a shown in FIG. 9. The base end side of the handle shaft 22 is immersed in and supported by the support portion 23.

[0018] The support portion 23 is provided at the longitudinal end of the gripping portion 21 and has a substantially cylindrical shape extending in a direction orthogonal to the longitudinal direction. The support portion 23 supports the handle shaft 22 and is configured to be insertable into the hole portion 31 of the handle pedestal 3 described later. As shown in FIGS. 11 and 12, a pair of opposing flat portions 231 as non-interference portions are provided on the outer periphery of the support portion 23. The flat portion 231 is a surface orthogonal to the short direction of the handle lever 2. The configuration of the non-interference portion is not limited to the flat portion 231, and any portion that does not interfere with the convex portion 312 when the support portion 23 is inserted into the hole portion 31 at a predetermined angle described later may be used. For example, a concave portion corresponding to the shape of the convex portion 312 may be used. A groove portion 232 is provided on the base end side of the support portion 23 relative to the flat portion 231 on the side portion of the support portion 23.

[0019] The handle pedestal 3 fixes the handle lever 2 to the main body portion 5a and the back plate 6 via the airtight case 4. As shown in FIG. 7, the handle pedestal 3 has a substantially rectangular parallelepiped shape and has a hole portion 31, a holding portion 32, a fixing portion 33, and a screw hole 34. The handle pedestal 3 is made of, for example, resin.

[0020] The hole portion 31 is a hole portion into which the handle shaft 22 and the support portion 23 of the handle lever 2 can be inserted. A pair of opposing convex portions 312 are provided on a part of the inner surface of the hole portion 31. The shape of the convex portion 312 is not particularly limited. For example, the tip is flat, and the flat surface is orthogonal to the longitudinal direction of the handle pedestal 3. The convex portion 312 is configured such that the support portion 23 can be completely inserted into the hole portion 31 only when the positions of the pair of flat portions 231 coincide with the positions of the convex portion 312. That is, the support portion 23 can be inserted into the hole portion 31 of the handle pedestal 3 only at a predetermined angle (in this embodiment, the angle formed by the longitudinal direction of the handle lever 2 and the longitudinal direction of the handle pedestal 3 is 90 degrees). On the other hand, even if the support portion 23 is inserted into the hole portion 31 of the handle pedestal 3 at an angle other than 90 degrees (for example, 80 degrees) described above, the insertion of the support portion 23 is restricted by the convex portion 312. The convex portion 312 is disposed at a position corresponding to the groove portion 232 in a state where the support portion 23 is completely inserted into the hole portion 31 with respect to the hole portion 31. In this state, the handle lever 2 is rotatable with respect to the handle shaft 22.

[0021] The procedure for assembling the handle lever 2 to the handle pedestal 3 will be described below. As shown in Fig. 13, with the position of the flat portion 231 aligned with the position of the convex portion 312, the handle shaft 22 and the support portion 23 are inserted into the hole portion 31 at a position where the longitudinal direction of the handle lever 2 is orthogonal to the longitudinal direction of the handle pedestal 3. Thereafter, the handle lever 2 is rotated to any position within the operating region y1 of the handle lever 2 shown in Fig. 14, and the tip end portion of the handle shaft 22 is inserted into the shaft hole 501 of the arm 50a shown in Fig. 9. Thereafter, the handle lever 2 is rotated to a position where the screw hole 34 is exposed, and the screw F1 shown in Fig. 4 is inserted through the screw hole 34 to fix the handle lever 2 and the handle pedestal 3 to the airtight case 4 and the back plate 6. After fixing, as shown in Fig. 15, the handle lever 2 is rotated to be parallel to the handle pedestal 3. After fixing, in any position within the operating region y1, the position of the flat portion 231 does not coincide with the position of the convex portion 312, and the convex portion 312 is engaged and fixed to the groove portion 232. With the above-described configuration of the handle lever 2 and the handle pedestal 3, washers, O-rings, etc. are not required, the number of parts of the sub-block 1a can be significantly reduced, and the airtightness between the handle lever 2 side and the airtight case 4 side can be ensured.

[0022] On the back side of the hole portion 31 that abuts against the airtight case 4, as shown in Fig. 7, a cylindrical portion 311 having a substantially cylindrical shape with the periphery of the hole portion 31 protruding is formed. The edge of the cylindrical portion 311 is a surface perpendicular to the protruding direction of the cylindrical portion 311 that can abut against the airtight case 4.

[0023] The holding portion 32 protrudes from the back side of the handle pedestal 3 and has a substantially cylindrical shape. The holding portion 32 is provided so as to coincide with the position of the screw head of the screw F2 that fixes the airtight case 4 to the back plate 6 when the handle pedestal 3 is assembled to the airtight case 4 as shown in Fig. 4. The holding portion 32 can be used as a positioning means when assembling the handle pedestal 3 by holding the screw head of the screw F2 on the inner peripheral side. With the holding portion 32, it is not necessary to perform hole processing for positioning on the main body portion, and the airtightness of the lock mechanism can be further improved.

[0024] The fixing part 33 protrudes from the back side of the handle pedestal 3 and has a substantially square tube shape. As shown in FIG. 4, when the handle pedestal 3 is fixed to the back plate 6 via the airtight case 4, the fixing part 33 is provided so as to be insertable into the fixing hole 61 of the back plate 6. Since the rotation of the handle pedestal 3 is restricted by the holding part 32 and the fixing part 33, the number of screws for fixing the sub-block 1a can be minimized. Further, since it is not necessary to form holes for positioning and fixing in the airtight case 4 or the main body part 5a, the airtightness between the indoor side and the outdoor side can be ensured.

[0025] As shown in FIG. 4, the screw hole 34 is a screw hole that can be screwed with a screw F1 for fixing the handle pedestal 3 to the back plate 6 via the airtight case 4 and the main body part 5a. On the back side of the handle pedestal 3, a cylindrical part having a substantially cylindrical shape and protruding around the screw hole 34 is formed.

[0026] The airtight case 4 as an airtight structure closes the opening on the outdoor side where the main body part 5a is disposed, thereby ensuring the airtightness between the expected surface on the indoor side of the vertical frame of the frame body 11 where the handle lever 2 is disposed and the found surface on the outdoor side of the vertical frame of the frame body 11 where the opening 111 for inserting the sub-block 1a is formed. The airtight case 4 makes it difficult for outside air to flow to the back side of the vertical frame, and it is possible to make it difficult for the user to feel unpleasant cold air when operating the handle lever 2.

[0027] As shown in FIG. 4, the airtight case 4 is a box-shaped body in which the main body part 5a is disposed inside, and has an opening corresponding to the operating region of the arm 50a. The airtight case 4 is composed of two members, a lid member 41 and a mounting member 42. By disposing the main body part 5a between the lid member 41 and the mounting member 42 and fitting and fixing the lid member 41 and the mounting member 42, the main body part 5a can be disposed inside the airtight case 4. The airtight case 4 is made of, for example, resin.

[0028] The lid member 41 is a member on the side that contacts the handle pedestal 3. FIG. 6 is a view of the airtight case 4 viewed from the lid member 41 side. As shown in FIG. 6, the lid member 41 has screw holes 411 and 413 and a shaft hole 412.

[0029] The shaft hole 412 is a hole through which the handle shaft 22 is inserted. The diameter of the shaft hole 412 is smaller than the outer diameter of the cylindrical portion 311. Around the shaft hole 412, a stepped portion 412a, which is a recess capable of arranging the cylindrical portion 311, is provided. The stepped portion 412a is configured to be larger than the outer diameter of the cylindrical portion 311 so as to absorb mounting errors, and to prevent the shaft hole 412 from being exposed to the outside during mounting. The end of the cylindrical portion 311 and the stepped portion 412a are fixed with their surfaces in contact with each other. Thereby, it is possible to prevent air flowing in from the opening where the arm 50a operates from leaking to the indoor side.

[0030] The screw holes 411 and 413 are holes through which the screws F2 and F1 are inserted, respectively. Around the screw hole 411, a stepped portion 411a, which is a recess capable of arranging the holding portion 32, is provided. Around the screw hole 413, a stepped portion 413a, which is a recess capable of arranging the cylindrical portion formed around the screw hole 34, is provided. The stepped portion 411a and the stepped portion 413a have the same configuration as the stepped portion 412a, and the end of the holding portion 32 and the stepped portion 411a are fixed with their surfaces in contact with each other. The end of the cylindrical portion formed around the screw hole 34 and the stepped portion 413a are fixed with their surfaces in contact with each other. Thereby, it is possible to prevent air flowing in from the opening where the arm 50a operates from leaking to the indoor side.

[0031] As shown in FIG. 4, the mounting member 42 is a member on the side that contacts the back plate 6. FIG. 8 is a view of the mounting member 42 as viewed from the lid member 41 side. The mounting member 42 has convex portions 421 at positions corresponding to the convex portions 52a and 52b of the second plate member 52 described later, respectively. The convex portion 421 is integrally formed as a thick portion of the mounting member 42 formed of, for example, resin. The mounting member 42 has holes through which the screws F1 and F2 can be inserted.

[0032] As shown in FIG. 6, the airtight case 4 has a flange 414 arranged along the opening 111 of the frame body 11 and a recess 415 provided on the back side of the flange 414. The recess 415 enables the sub-block 1a to be easily attached to the frame body 11. The function of the recess 415 will be described in detail later.

[0033] As shown in FIG. 4, the main body portion 5a is composed of an arm 50a, a first plate member 51, and a second plate member 52. The arm 50a is rotatably sandwiched by the first plate member 51 and the second plate member. The main body portion 5a is made of, for example, metal.

[0034] As shown in FIG. 9, the arm 50a has a tip portion having a substantially U-shaped form protruding from the airtight case 4, a shaft hole 501 into which the tip of the handle shaft 22 is inserted and engaged, a locking hole 502a, and an unlocking hole 502b. The arm 50a is rotatably fixed within a predetermined operating range about the shaft hole 501 as the axis. The tip portion of the arm 50a can be engaged with an engaging portion 122 provided on the prospective surface on the side that contacts the frame body 11 of the vertical frame of the shoji 12.

[0035] The first plate member 51 is a plate-like member disposed on the lid member 41 side, and the second plate member 52 is a plate-like member disposed on the mounting member 42 side. The pair of plate members, the first plate member 51 and the second plate member 52, has a substantially H-shaped form and has hole portions through which screws F1 and F2 can be inserted. A hole portion through which the handle shaft 22 can be inserted is formed in the first plate member 51.

[0036] The first plate member 51 and the second plate member 52 rotatably sandwich the arm 50a and hold the arm 50a at the locking position and the unlocking position by click fitting so that the user can discriminate between the locked state and the unlocked state of the sub-block 1a by the operating feeling of the handle lever 2. As used in this specification, "click fitting" not only means a simple fitting between members, but also means a fitting accompanied by an operating feeling such as a sound feeling and a tactile feeling generated when the arm 50a moves to the locking position and the unlocking position along with the operation of the handle lever 2. Thus, the above click fitting is intended to transmit an operating feeling to the user as a sound and a tactile feeling to the fingers. Also, the above click fitting can hold the arm 50a against the force of the arm 50a moving from the locking position to the unlocking position due to the self-weight of the arm 50a, wind pressure, vibration, etc. The above click fitting can be realized by the following configuration.

[0037] As shown in FIG. 9, the first plate member 51 and the second plate member 52 sandwich the locations where the locking hole 502a and the unlocking hole 502b of the arm 50a are provided, except for the locations where holes through which the screws F1 and F2 can be inserted and a hole through which the handle shaft 22 can be inserted are provided, and are biased in the direction of sandwiching the arm 50a. As shown in FIG. 10, the second plate member 52 has a convex portion 52a and a convex portion 52b. The convex portion 52a and the convex portion 52b are formed integrally with the second plate member. This can reduce the number of parts of the sub-block 1a.

[0038] FIG. 9 is a view of the main body portion 5a as viewed from the side of the first plate member 51, and shows the position where the arm 50a engages with the engaging portion 122. At this position, as shown in FIG. 10, the convex portion 52a of the second plate member fits into the locking hole 502a. When the user operates the handle lever 2 in FIG. 9 and the arm 50a rotates downward, the convex portion 52a is overcome by the locking hole 502a, and the operating feeling is transmitted to the user's fingers. When the user operates the handle lever 2 and moves the arm 50a to the lowermost position in the operating region, the unlocking hole 502b enters the convex portion 52b, the operating feeling is transmitted to the user's fingers, the convex portion 52b of the second plate member fits into the unlocking hole 502b, and the engagement between the arm 50a and the engaging portion 122 is disengaged, and the shoji 12 is in the unlocked state. By providing the convex portions 52a and 52b that fit with the locking hole 502a and the unlocking hole 502b on the main body portion 5a itself, the above click fit can be realized without increasing the number of parts. Further, convex portions 421 are formed at positions corresponding to the convex portions 52a and 52b of the mounting member 42, respectively. Thereby, the above fitting force can be increased without increasing the number of parts. In the present embodiment, the convex portions 421 corresponding to the convex portions 52a and 52b are formed separately, but the present invention is not limited to this, and a long convex portion 421 may be used as long as it can correspond to the convex portions 52a and 52b.

[0039] The back plate 6 is a plate-shaped member that fixes the handle lever 2, the handle pedestal 3, the airtight case 4, and the main body portion 5a to the vertical frame of the frame body 11. By fixing the respective members via the back plate 6, the mounting accuracy of each member can be improved, and the airtightness of the sub-block 1a can be further improved. In addition to the above, since the sub-block 1 can be firmly fixed, the crime prevention performance can be improved. The back plate 6 is made of, for example, metal. The back plate 6 is provided with a fixing hole 61 through which the fixing portion 33 of the handle pedestal 3 can be inserted. In addition to the above, the back plate 6 is formed with a hole portion into which screws F1 and F2 can be screwed, and a hole portion through which a fixture for fixing the back plate 6 to the vertical frame can be inserted.

[0040] Next, with reference to FIGS. 18 to 22, a state in which the opening of the frame body 11 where the sub-block 1a is disposed is closed by the airtight case 4 will be described.

[0041] FIG. 18 is a view of the sub-block 1a disposed on the prospective surface of the frame body 11 (vertical frame) viewed from the finding direction. The right side where the handle lever 2 and the handle pedestal 3 in FIG. 21 are disposed is the indoor side, and the left side where the arm 50a is disposed is the outdoor side. FIG. 19 is a cross-sectional view taken along line B-B in FIG. 21. The handle pedestal 3 and the airtight case 4 are fixed in contact with each other on their surfaces.

[0042] As shown in FIGS. 20 to 22, the outdoor space Z and the internal space Y of the frame body 11 are closed by the airtight case 4. The frame body 11 is provided with an opening 111 for disposing the sub-block 1a and operating the arm 50a. The periphery of the opening 111 is covered by the airtight case 4. An air flow can flow into the airtight case 4 from the opening 111. However, the airtight case 4 has a configuration in which it has no opening other than the opening 111 so that the air flow flowing into the airtight case 4 through the opening 111 does not flow out to the outside of the airtight case 4. For this reason, the air flowing from the outdoor space Z does not reach the internal space Y of the frame body 11 or the indoor side, and it is possible to make it difficult for the user to feel unpleasant cold air when operating the handle lever 2.

[0043] (Method of attaching the sub-block to the sliding window) The method of attaching the sub-block 1a to the sliding-out window 100 includes the steps of arranging the main body 5a inside the airtight case 4, fixing the back plate 6 to the vertical frame of the frame body 11, inserting and engaging the engagement pin 143 into the hole 50a1 of the arm 50a as shown in FIG. 16, inserting the airtight case 4 into the opening 111 while rotating it about the engagement pin 143 as the central axis as shown in FIG. 17, and fixing the airtight case 4, the main body 5a, the handle pedestal 3, and the handle lever 2 to the back plate 6.

[0044] As shown in FIG. 16, the main body 5a of the sub-block 1a is inserted and fixed into the room side from the opening 111 provided in the vertical frame of the frame body 11 in a state where the hole 50a1 of the arm 50a is engaged with the engagement pin 143. However, since the main body 5a is covered by the airtight case 4 having a flange 414 for closing the opening 111, it is necessary to prevent interference between the flange 414 and the periphery of the opening 111 when inserting the airtight case 4 into the opening 111. In this regard, a recess 415 is provided on the back side of the flange 414 of the airtight case 4. Thereby, when the airtight case 4 is rotated about the engagement pin 143 as the central axis and inserted into the opening 111, the recess 415 can be inserted into the edge of the opening 111, so that the airtight case 4 can be inserted into the opening 111, and interference between the flange 414 and the periphery of the opening 111 can be prevented.

[0045] The present disclosure is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope that can achieve the object of the present disclosure are included in the present disclosure.

Explanation of Reference Numerals

[0046] 1a Sub-block (locking mechanism), 2 Handle lever, 3 Handle pedestal, 4 Airtight case (airtight structure), 414 Flange, 415 Recess, 421 Protrusion, 5a Main body, 50a Arm, 51 First plate member, 52 Second plate member, 6 Back plate, 100 Sliding-out window (fitting), 11 Frame body, 12 Shoji, 122 Engagement portion

Claims

1. A locking mechanism for a building fitting, comprising: a main body portion, an airtight case covering the main body portion, and a handle lever; the main body portion includes an arm that engages with an interlocking bar provided on a frame of the building fitting; the airtight case has a flange portion arranged along an opening of the frame; a recess is formed on a back side of the flange portion of the airtight case; the main body portion, the airtight case, and the handle lever are fixed to the frame; the airtight case is composed of a first member and a second member, and the main body portion is arranged between the first member and the second member; the airtight case is fixed along a direction in which the first member and the second member are fitted together, the locking mechanism.

2. The locking mechanism according to claim 1, wherein the airtight case is fixed in a direction same as the fitting direction.

3. The locking mechanism according to claim 1 or 2, wherein the airtight case is a box-shaped body in which the main body portion is arranged inside.

4. The locking mechanism according to any one of claims 1 to 3, wherein the main body portion, the airtight case, and the handle lever are fixed to the frame via a back plate.

5. The handle lever has a handle pedestal that fixes the handle lever to the main body portion and the back plate via the airtight case, the handle pedestal has a fixing portion protruding toward the back plate side, the back plate has a fixing hole through which the fixing portion can be inserted, the locking mechanism according to claim 4.

6. The handle lever has a handle pedestal that fixes the handle lever to the main body portion and the back plate via the airtight case, the handle pedestal has a cylindrical holding portion protruding toward the back plate side, a fixture for fixing the airtight case to the back plate is held on an inner peripheral side of the holding portion, the locking mechanism according to claim 4.

7. A building fitting comprising the locking mechanism according to any one of claims 1 to 6.

8. A method of attaching the locking mechanism according to any one of claims 1 to 6 to a building fitting, comprising: engaging the arm with an engagement pin of the interlocking bar; inserting the airtight case into the opening from the outdoor side while rotating the airtight case about the engagement pin. A method of attaching the locking mechanism to an escape window.

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