Locking mechanism and building inspection hatch

Abstract

To provide a lock mechanism capable of surely preventing careless rotation of an operation shaft and being easily mounted on an inner frame, and a building inspection hole provided with such a lock mechanism.SOLUTION: A lock mechanism 1 includes: an operation shaft 8 provided at a position opposed to an inner surface of an outer frame in an inner frame; a bearing 9 for rotatably mounting the operation shaft 8 to the inner frame; an operation receiving part 8E provided on the operation shaft 8 and receiving the rotating operation to the operation shaft 8; a locking part 10 provided on the operation shaft 8 and detachably locked to the outer frame by the rotation of the operation shaft 8; and a spring member 11 inserted between the bearing 9 and the operation shaft 8 and having a sandwiching part 11C sandwiching the operation shaft 8 therebetween.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The technology disclosed in the present invention relates to a locking mechanism and a building inspection hatch. [Background technology]

[0002] Patent document 1 describes a structure for a ceiling inspection hatch that is equipped with a locking means for keeping the inner frame closed by rotating a locking shaft that is rotatably attached to the inner frame and faces in the vertical direction, thereby engaging a claw piece located near the lower end of the locking shaft with the outer frame.

[0003] In this structure, the lock shaft has a flat portion on the back surface that abuts against the outer surface of the upright wall when the claw is in the locked state, with the flat portion facing perpendicular to the outer surface of the upright wall, and the lock shaft has a flat portion that connects to this flat portion. The connecting portion of these flat portions has a corner, and a spring presses the lock shaft against the outer surface of the upright wall of the inner frame, thereby forming a click mechanism that restricts rotation in the unlocking direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-301599 Summary of the Invention [Problem to be solved by the invention]

[0005] In outdoor building inspection hatches, it is desirable to prevent the locking shaft of the inner frame of the building inspection hatch from accidentally rotating in the unlocking direction even if vibrations caused by wind or the like act on the locking shaft.

[0006] For example, in the structure described in Patent Document 1, as described above, the lock shaft is pressed against the outer surface of the rising wall of the inner frame by a spring, thereby restricting rotation of the lock shaft in the unlocking direction.

[0007] However, with a structure in which the end of a spring is inserted into a hole in the raised wall of the inner frame and the spring presses the locking shaft against the raised wall of the inner frame, it is difficult to attach the spring to the inner frame in a way that generates the desired rotation restriction force.

[0008] Furthermore, in such a structure, rotation of the lock shaft may loosen the attachment of the spring to the inner frame.

[0009] An object of the present invention is to provide a locking mechanism that can reliably prevent inadvertent rotation of an operating shaft and that can be easily attached to an inner frame, and a building inspection hatch equipped with such a locking mechanism. [Means for solving the problem]

[0010] The first aspect of the locking mechanism is a locking mechanism that locks the inner frame to the outer frame when the inner frame is positioned inside the outer frame of a building inspection hatch, and includes an operating shaft that is provided in the inner frame at a position facing the inner surface of the outer frame, a bearing that rotatably attaches the operating shaft to the inner frame, an operating receiving portion that is provided on the operating shaft and receives rotational operation of the operating shaft, a locking portion that is provided on the operating shaft and locks the inner frame to the outer frame in a manner that allows it to be engaged or disengaged with by rotation of the operating shaft, and an insert member that is inserted between the bearing and the operating shaft and has a clamping portion that clamps the operating shaft therebetween.

[0011] In this locking mechanism, an insert is inserted between the bearing and the operating shaft, and the clamping portion of the insert is clamped between the operating shaft, making it easy to attach to the inner frame. Furthermore, in the locking mechanism, the bearing restricts the rotation of the insert, and the clamping portion clamps and contacts the operating shaft, so frictional force acts on the rotation of the operating shaft, providing resistance to its rotation. This makes it possible to more reliably prevent inadvertent rotation of the operating shaft than with a structure in which a spring presses the operating shaft against the inner frame.

[0012] In the lock mechanism of the second aspect, the holding portion of the bearing that rotatably holds the operating shaft presses the pinching portion of the insertion member against the operating shaft.

[0013] The holding portion of the bearing presses the clamping portion of the insert member against the operating shaft, thereby generating a stronger frictional force against the operating shaft and preventing the clamping portion from loosening its clamping force on the operating shaft.

[0014] In the locking mechanism of the third aspect, the insertion member has an elastic connecting portion that connects the ends of the pair of clip portions together.

[0015] The elasticity of the elastic connecting portion allows the clamping portion to be pressed against the operating shaft, preventing the clamping force of the operating shaft from loosening and also facilitating the attachment of the insertion member.

[0016] In the lock mechanism of the fourth aspect, the bearing is provided with an insertion portion into which the elastic connecting portion of the insertion member is inserted.

[0017] Since the elastic connecting portion of the insert member is inserted into the insertion portion of the bearing, the rotation of the insert member is restricted, a stronger frictional force can be generated against the operating shaft, and the clamping portion can reliably maintain the state in which it clamps the operating shaft.

[0018] In the lock mechanism of the fifth aspect, the clamping portion of the insertion member is provided with a curved portion that curves along the outer circumferential surface of the operating shaft.

[0019] By providing a curved portion on the clamping portion of the insertion member, the contact area between the clamping portion and the operating shaft is increased, which generates a stronger frictional force against the operating shaft and also ensures that the clamping portion can maintain the state in which it clamps the operating shaft.

[0020] The sixth aspect of the building inspection hatch has an outer frame that is fitted into an opening in a building, an inner frame that has a closed position located inside the outer frame and an open position that allows it to come out of the outer frame, and a locking mechanism of any one of the first to fifth aspects.

[0021] With this building inspection hatch, the locking mechanism for the inner frame can be easily installed, and inadvertent rotation of the operating shaft can be prevented. [Effects of the Invention]

[0022] According to the present invention, it is possible to obtain a locking mechanism that can reliably prevent inadvertent rotation of the operating shaft and that is easy to attach to the inner frame, as well as a building inspection hatch equipped with such a locking mechanism. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing a building inspection hatch equipped with a locking mechanism of the first embodiment in a closed state together with an opening in a building, viewed from below. [Figure 2] FIG. 2 is a perspective view showing the building inspection hatch equipped with the locking mechanism of the first embodiment in an open state, as viewed from below. [Figure 3] FIG. 3 is a perspective view showing the building inspection hatch equipped with the locking mechanism of the first embodiment in a closed state, as viewed from above. [Figure 4] FIG. 4 is a partially enlarged perspective view of the building inspection hatch of the first embodiment, showing the vicinity of the locking mechanism. [Figure 5] FIG. 5 is a partially enlarged perspective view showing the building inspection hatch of the first embodiment near the locking mechanism. [Figure 6] FIG. 6 is a partially enlarged perspective view showing the building inspection hatch of the first embodiment near the locking mechanism. [Figure 7] FIG. 7 is an exploded perspective view showing the locking mechanism of the first embodiment. [Figure 8A] FIG. 8A is a cross-sectional view showing the locking mechanism of the first embodiment in a state where the locking portion is locked to the outer frame, taken along a cross section perpendicular to the operating shaft. [Figure 8B] FIG. 8B is a cross-sectional view taken along line BB in FIG. 8A, showing the locking mechanism of the first embodiment. [Figure 9A] FIG. 9A is a cross-sectional view showing the locking mechanism of the first embodiment in a state where the locking portion is not locked to the outer frame, taken along a cross section perpendicular to the operating shaft. [Figure 9B] FIG. 8B is a cross-sectional view taken along line BB in FIG. 9A, showing the locking mechanism of the first embodiment. [Figure 10A]FIG. 10A is a cross-sectional view showing the locking mechanism of the second embodiment in a state where the locking portion is locked to the outer frame, taken along a cross section perpendicular to the operating shaft. [Figure 10B] FIG. 10B is a cross-sectional view taken along line BB in FIG. 10A, showing the locking mechanism according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an example of an embodiment of the present application will be described in detail with reference to the drawings.

[0025] Fig. 1 shows a locking mechanism 1 of a first embodiment and a ceiling inspection hatch 2 equipped with this locking mechanism 1. Figs. 2 and 3 show the ceiling inspection hatch 2 equipped with the locking mechanism 1 of the first embodiment. Furthermore, Figs. 4 to 7 show an enlarged view of the locking mechanism 1.

[0026] The ceiling inspection hatch 2 is an example of a building inspection hatch. In addition to the ceiling inspection hatch 2, the building inspection hatch may also be, for example, a wall inspection hatch provided on the wall of a building.

[0027] The ceiling inspection hatch 2 has an outer frame 3 and an inner frame 4. The outer frame 3 is adapted to be fitted into an opening 6 (see FIG. 1) in a ceiling 5, and essentially forms the outer contour of the ceiling inspection hatch 2. In the example disclosed herein, the outer frame 3 is a square frame-shaped member. The outer frame 3 and the inner frame 4 are formed, for example, from an extruded aluminum material. As shown in FIGS. 8A to 9B, a notch 3C is provided below the locking mechanism 1 of the outer frame 3 to prevent interference when the inner frame 4 is opened or closed. When the inner frame 4 is in the closed position, the notch 3C is hidden by the lower flange 4B and is not exposed.

[0028] The inner frame 4 is disposed inside the outer frame 3. In the example disclosed in the present application, the inner frame 4 is a square frame-shaped member corresponding to the outer frame 3.

[0029] An inner plate 7 is fixed to the inside of the inner frame 4, and the inside of the inner frame 4 is covered with the inner plate 7.

[0030] A hinge (not shown) is provided between one side 4A of the inner frame 4 and one side 3A of the outer frame. The inner frame 4 is attached to the outer frame 3 by this hinge so as to be rotatable in the directions of arrows S1 and S2 shown in Fig. 2. The inner frame 4 rotates between the closed position shown in Figs. 1 and 3 and the open position shown in Fig. 2.

[0031] When the inner frame 4 is in the closed position (the state shown in Figures 1 and 3), the inner frame 4 is located inside the outer frame 3, and the ceiling inspection hatch 2 is closed by the inner frame 4 including the inner plate 7. In this state, the inner plate 7 is flush with the ceiling 5, creating an appearance that is integrated with the ceiling 5.

[0032] In contrast, when the inner frame 4 is in the open position (the state shown in Figure 2), the inner frame 4 including the inner panel 7 is positioned so as to come out of the outer frame 3, and the ceiling inspection hatch 2 is in an open state. By opening the ceiling inspection hatch 2 in this way, it becomes possible to access the upper side of the ceiling 5 (the attic) from the lower side (the room side) of the ceiling 5.

[0033] 4 to 6, a bottom flange 4B, a top flange 4C, and a middle flange 4D are formed on the inner frame 4. The bottom flange 4B extends outward (indicated by arrow D1) and inward (indicated by arrow D2) from the inner frame 4. In contrast, the top flange 4C and the middle flange 4D extend outward from the inner frame 4.

[0034] A locking mechanism 1 is provided on the inner frame 4. In this embodiment, the locking mechanism 1 is provided on the outer side of the inner frame 4, on an opposite side 4E of the inner frame 4 opposite to the side 4A on which the hinge is provided (see FIG. 2).

[0035] 7, the lock mechanism 1 has an operating shaft 8, a bearing 9, a locking portion 10, and a spring member 11. The spring member 11 is an example of an insert member.

[0036] The operating shaft 8 is a cylindrical member, and is rotatably attached to the inner frame 4 by a bearing 9. The operating shaft 8 is positioned at an opposite side 4E opposite to the inner surface 3B of the outer frame 3 (see FIGS. 8A and 8B).

[0037] A large-diameter portion 8B having a larger diameter than the shaft body 8A is formed on the lower end side of the operating shaft 8, and a step portion 8C is formed between the shaft body 8A and the large-diameter portion 8B. The operating shaft 8 is inserted into a through-hole formed in the lower flange 4B at the position of the large-diameter portion 8B, and the lower end of the operating shaft 8 protrudes below the lower flange 4B.

[0038] An operation receiving groove 8D is formed at the lower end of the operating shaft 8. The operation receiving groove 8D is an example of an operation receiving portion, and is a portion that receives a rotational force on the operating shaft 8 from a tool such as a screwdriver when the operating shaft 8 is rotated. Specifically, the operating shaft 8 can be rotated by applying a rotational force to the operating shaft 8 in the circumferential direction (the directions of arrows R1 and R2: see Figure 7). The operation receiving groove 8D is an example of an operation receiving portion. Instead of the operation receiving groove 8D, it is possible to adopt, for example, a portion having a shape that matches the tool to be used.

[0039] The upper end side of the operating shaft 8 is fitted into a groove-shaped recess formed in the upper flange 4C, and the upper end 8F protrudes above the upper flange 4C. A locking portion 10 is attached to the upper end 8F of the operating shaft 8. Specifically, the upper end 8F passes through the locking portion 10, and the locking portion 10 is fixed to the operating shaft 8 by crimping the upper end of the operating shaft 8. This allows the locking portion 10 to rotate integrally with the operating shaft 8. In the intermediate flange 4D, a groove-shaped recess is provided in the mounting portion of the shaft main body 8A to allow clearance for the shaft main body 8A, and is formed to accommodate the shaft main body 8A.

[0040] The locking portion 10 is in contact with the upper surface of the upper flange 4C, and this restricts downward movement of the operating shaft 8 and the locking portion 10 relative to the inner frame 4.

[0041] Depending on the rotation angle of the operating shaft 8, the locking portion 10 can take a locking position (see FIGS. 4 and 6) where it protrudes more outward from the inner frame 4, or a non-locking position (see FIG. 5) where it protrudes less.

[0042] When the inner frame 4 is positioned inside the outer frame 3 and the locking portion 10 is in the locking position, as shown in Figure 3, the locking portion 10 is locked to the upper end of the outer frame 3, restricting rotation of the inner frame 4 relative to the outer frame 3 in the direction of arrow S1, and locking the inner frame 4 relative to the outer frame 3.

[0043] In contrast, when the locking portion 10 is in the unlocked position, the locking portion 10 is not locked to the upper end of the outer frame 3, and the locking portion 10 can be engaged with and disengaged from the outer frame 3. When the locking portion 10 is in the unlocked position, the inner frame 4, which is closing the ceiling inspection hatch 2, is not restricted from rotating in the direction of arrow S2, and the inner frame 4 can rotate in the direction of arrow S1 to open the ceiling inspection hatch 2.

[0044] A stopper 10A is formed on the locking portion 10. As shown in FIGS. 8A and 8B, when the locking portion 10 has rotated in the direction of arrow R1 from the unlocked position to the locked position, the stopper 10A faces the inner frame 4. If the locking portion 10 and operating shaft 8 attempt to rotate further in the direction of arrow R1, the stopper 10A abuts the inner frame 4 and prevents this rotation. Conversely, as shown in FIGS. 9A and 9B, even when the locking portion 10 has rotated in the direction of arrow R2 from the unlocked position to the locked position, the stopper 10A abuts the inner frame 4 and prevents further rotation of the locking portion 10 and operating shaft 8 in the direction of arrow R2.

[0045] The bearing 9 has a holding portion 9A formed in the center in the width direction and a pair of mounting portions 9B formed on both sides in the width direction of the holding portion 9A. A mounting hole 9C passes through the mounting portion 9B, and the bearing 9 is fixed to the inner frame 4 by a rivet 12 that passes through the mounting hole 9C and a mounting hole 4F (see FIG. 8A) formed in the inner frame 4.

[0046] The retaining portion 9A is formed in a curved shape so as to surround the shaft main body 8A of the operating shaft 8 from the opposite side of the inner frame 4. The inner surface of the retaining portion 9A surrounds the outer periphery of the shaft main body 8A, and holds the operating shaft 8 rotatably relative to the inner frame 4.

[0047] Also, as shown in FIG. 8B, the lower surface 9D of the holding portion 9A is in contact with the stepped portion 8C, thereby restricting the upward movement of the operating shaft 8 and the locking portion 10 relative to the bearing 9 and the inner frame 4.

[0048] As shown in FIG. 7, a spring member 11 is inserted between the bearing 9 and the operating shaft 8.

[0049] The spring member 11 is formed by bending a wire-shaped metal material at a predetermined position, and a resilient connecting portion 11A bent into a small-diameter arc is formed in the center portion. The portion from the resilient connecting portion 11A to both end portions 11B is made into a pair of clamping portions 11C, and the resilient connecting portion 11A connects the ends of the clamping portions 11C together. The resilience of the resilient connecting portion 11A biases the clamping portions 11C in directions toward each other, and the spring member 11 is configured to clamp the operating shaft 8 between the pair of clamping portions 11C.

[0050] In particular, in this embodiment, an annular fitting groove 8E is formed in the circumferential direction in the shaft main body 8A of the operating shaft 8. Furthermore, a curved portion 11D that curves along the outer circumferential surface of the operating shaft 8 is formed in a part of the clamping portion 11C. The two curved portions 11D are fitted into the fitting groove 8E, whereby the spring member 11 is attached to and supported by the operating shaft 8. In this state, the two curved portions 11D are in linear (arc-shaped) contact with the operating shaft 8 in the fitting groove 8E.

[0051] In this embodiment, the elastic connecting portion 11A is located farther from the inner frame 4 than the operating shaft 8, and the spring member 11 is arranged so that the clamping portion 11C extends obliquely from the elastic connecting portion 11A toward the inner frame 4.

[0052] The distance between the two curved portions 11D of the spring member 11 (the bending angle due to the elastic connecting portion 11A) is set so that, when the spring member 11 is attached to the operating shaft 8, the curved portions 11D come into close contact with the fitting groove 8E due to the elasticity of the spring member 11. Therefore, the spring member 11 contacts the operating shaft 8 at the two curved portions 11D so as to sandwich the operating shaft 8. Then, as the spring member 11 contacts the operating shaft 8, a frictional force (resistance force) acts against the rotation of the operating shaft 8 relative to the spring member 11.

[0053] When the spring member 11 is attached to and supported by the operating shaft 8, the inner surface of the holding portion 9A of the bearing 9 is in contact with the spring member 11, and the holding portion 9A presses the clamping portion 11C of the spring member 11 against the operating shaft 8.

[0054] An insertion hole 9E is formed in the center of the holding portion 9A of the bearing 9, penetrating in the plate thickness direction. An elastic connecting portion 11A of the spring member 11 is inserted into the insertion hole 9E, and the elastic connecting portion 11A partially protrudes from the opposite side of the inner frame 4. The spring member 11 is positioned between the inner frame 4 and the bearing 9, but by fitting the elastic connecting portion 11A into this insertion hole 9E, the spring member 11 is partially exposed from the bearing 9. By inserting the elastic connecting portion 11A, which is a part of the spring member 11, into the insertion hole 9E, the spring member 11 is fixed to the bearing 9 and is prevented from inadvertently rotating around the operating shaft 8. The insertion hole 9E is an example of an insertion portion.

[0055] Next, the operation of this embodiment will be described.

[0056] As shown in Figures 3, 8A and 8B, when the inner frame 4 is positioned inside the outer frame 3 and the locking portion 10 is in the locking position, the locking portion 10 is locked to the outer frame 3, so that the inner frame 4 is locked in the closed position relative to the outer frame 3.

[0057] In this state, by using the operating groove 8D to rotate the operating shaft 8 in the direction of arrow R2, and rotating the locking portion 10 to the unlocked position as shown in Figures 5, 9A and 9B, the locking portion 10 will no longer be locked to the outer frame 3, and the lock of the inner frame 4 to the outer frame 3 will be released, allowing the inner frame 4 to rotate from the closed position to the open position.

[0058] Incidentally, when ceiling inspection hatch 2 is installed outside a building, a rotational force may act on operating shaft 8 relative to inner frame 4 due to vibrations caused by wind or the like, for example.

[0059] In this embodiment, the clamping portions 11C of the spring member 11 contact the operating shaft 8 at two locations that clamp the operating shaft 8, thereby applying a frictional force that resists the rotation of the operating shaft 8. Therefore, compared to a configuration that does not have a member that generates such resistance to the rotation of the operating shaft 8, or a conventional configuration in which a spring presses the operating shaft against the inner frame to apply frictional force, a resistance force can be reliably applied to the rotation of the operating shaft 8. As a result, even if a rotational force acts on the operating shaft 8 due to vibrations caused by wind or the like, the rotation of the operating shaft 8 can be prevented, and it is possible to prevent the operating shaft 8 and the locking portion 10 from accidentally rotating from the locked state to the locked state.

[0060] Furthermore, in conventional configurations, it can be difficult to attach a pressing member or the like to the inner frame 4 in order to stably obtain a desired amount of force (for example, a pressing force against the operating shaft 8) to prevent inadvertent rotation of the operating shaft 8 and the locking portion 10, due to the structure and shape of the inner frame 4. There is also a risk that rotation of the operating shaft 8 may cause the pressing member or the like to loosen from the inner frame 4. In contrast, with the technology disclosed in the present invention, the spring member 11 is not fixed to the inner frame 4, so it is possible to maintain a state in which the spring member 11 can stably exert a frictional force that acts as resistance to rotation of the operating shaft 8. For example, even if the operating shaft 8 rotates, the attachment of the spring member 11 will not loosen.

[0061] Furthermore, in the spring member 11, the clamping portion 11C is connected by the elastic connecting portion 11A, and the elasticity of the elastic connecting portion 11A causes the clamping portion 11C to clamp and press the operating shaft 8. Therefore, compared to the conventional configuration, it is possible to make the resistance to the rotation of the operating shaft 8 (frictional force with the clamping portion 11C) stronger.

[0062] Furthermore, the holding portion 9A of the bearing 9 presses the pinching portion 11C of the spring member 11 against the operating shaft 8. Therefore, compared to the conventional configuration, a stronger frictional force can be generated against the operating shaft 8.

[0063] Furthermore, the elastic connecting portion 11A of the spring member 11 is inserted into the insertion hole 9E of the bearing 9, and the spring member 11 is supported by the bearing 9 by the elastic connecting portion 11A. Therefore, the position and posture of the spring member 11 relative to the bearing 9 can be stably maintained. For example, it is possible to prevent the spring member 11 from accidentally rotating in the circumferential direction of the operating shaft 8, and the position of the spring member 11 relative to the operating shaft 8 is also stabilized, so that the state in which the clamping portion 11C clamps the operating shaft 8 can be stably maintained.

[0064] Furthermore, since the insertion hole 9E of the bearing 9 penetrates the holding portion 9A of the bearing 9 in the plate thickness direction, the elastic connecting portion 11A of the spring member 11 is exposed on the opposite side of the operating shaft 8 and can be seen.

[0065] However, instead of the insertion hole 9E that penetrates the bearing 9, the insertion portion for the elastic connecting portion 11A of the spring member 11 may have a shape that is simply recessed on the operating shaft 8 side without penetrating the bearing 9. In other words, by fitting the elastic connecting portion 11A into this recessed portion, a structure can be realized in which the spring member 11 is supported by the bearing 9. In a structure in which the elastic connecting portion 11A is fitted into the recessed portion of the bearing 9, the spring member 11 is not exposed from the bearing 9.

[0066] Furthermore, curved portion 11D of spring member 11 is curved along the outer peripheral surface of operating shaft 8 (fitting groove 8E in this embodiment), and curved portion 11D is in line contact with the outer peripheral surface of operating shaft 8. Therefore, compared to a conventional configuration in which a spring presses the operating shaft against the inner frame to apply frictional force, it is possible to maintain a stable contact state and suppress wear on the outer peripheral surface of operating shaft 8.

[0067] Furthermore, since curved portion 11D of spring member 11 is fitted into fitting groove 8E of operating shaft 8, the position of spring member 11, particularly the position in the axial direction (longitudinal direction) of operating shaft 8, can be stably maintained.

[0068] However, even in a structure that does not have such an insertion groove 8E, by bending the curved portion 11D of the spring member 11 along the outer peripheral surface of the operating shaft 8, a structure can be realized in which the curved portion 11D is in line contact with the outer peripheral surface of the operating shaft 8.

[0069] Next, a second embodiment will be described. In the second embodiment, the same elements, members, etc. as those in the first embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted. Furthermore, since the specific structure of the ceiling inspection hatch in the second embodiment is the same as that in the first embodiment, illustrations and descriptions thereof will be omitted.

[0070] 10A and 10B, the locking mechanism 21 of the second embodiment differs from the first embodiment in the arrangement and shape of the spring member 11. That is, in the second embodiment, the elastic connecting portion 11A is located close to the opposite side 4E of the inner frame 4, and both end portions 11B are arranged in a direction extending toward the bearing 9. In addition, the elastic connecting portion 11A is formed with a bent portion 11F that is bent upward, so that even if the gap between the operating shaft 8 and the opposite side 4E is narrow, the elastic connecting portion 11A can be arranged in this gap.

[0071] In addition, in the second embodiment, the insertion hole 9E of the bearing 9 is larger in diameter (or longer) than the insertion hole 9E of the bearing 9 in the first embodiment, and the two end portions 11B are inserted into one insertion hole 9E.

[0072] In the second embodiment configured as described above, when a rotational force is applied to the operating shaft 8 due to vibrations caused by wind or the like, the rotation of the operating shaft 8 can be prevented, and it is possible to prevent inadvertent rotation from the locked state to the non-locked state. In other respects as well, the same effects as those of the first embodiment can be achieved.

[0073] With the technology disclosed in this application, in order to prevent inadvertent rotation of the operating shaft 8, it is sufficient to essentially place the spring member 11 between the bearing 9 and the operating shaft 8, and there is no need to join other members or to process the bearing 9 and the operating shaft 8. As a result, the locking mechanisms 1, 62 and ceiling inspection hatch 2 can be constructed at low cost, and the components that make up the locking mechanisms 1, 21 are also easy to assemble.

[0074] Furthermore, because the operating shaft 8 can be rotatably attached to the inner frame 4 by the bearing 9 with the spring member 11 inserted between the bearing 9 and the operating shaft 8, less processing of the inner frame 4 is required. This makes it possible to manufacture the ceiling inspection hatch 2 easily and at low cost.

[0075] Furthermore, by using spring members 11 with different physical properties, for example, different elastic forces of the elastic connecting portions 11A, the resistance force acting on the rotation of the operating shaft 8 can be easily set to a desired magnitude. [Explanation of symbols]

[0076] 1 Locking mechanism 2 Ceiling inspection hatch 3 Outer frame 3B Inner surface 4 Inner frame 5 Ceiling 6 Opening 8 Operation shaft 8D Operation receiving groove 8E Fitting groove 9 Bearing 9A Holding portion 9C Mounting hole 9D Underside 9E Insertion hole 10 Locking portion 11 Spring member 11A Elastic connecting portion 11B Both ends 11C Clamping portion 11D Curved portion

Claims

1. A locking mechanism that locks the inner frame to the outer frame when the inner frame is positioned inside the outer frame of the building inspection hatch, an operating shaft provided in the inner frame at a position facing the inner surface of the outer frame; a bearing for rotatably mounting the operating shaft to the inner frame; an operation receiving portion provided on the operation shaft and receiving a rotation operation of the operation shaft; a locking portion provided on the operating shaft for detachably locking the inner frame to the outer frame by rotation of the operating shaft; an inserting member that is inserted between the bearing and the operating shaft and has a clamping portion that clamps the operating shaft therebetween; A locking mechanism.

2. 2. The locking mechanism according to claim 1, wherein a holding portion of the bearing that rotatably holds the operating shaft presses the clamping portion of the insertion member against the operating shaft.

3. 3. The locking mechanism according to claim 1, wherein the inserting member has an elastic connecting portion that connects the ends of the pair of clip portions together.

4. 4. The locking mechanism according to claim 3, wherein the bearing is provided with an insertion portion into which the elastic connecting portion of the insert member is inserted.

5. 5. The locking mechanism according to claim 1, wherein the clamping portion of the insertion member is provided with a curved portion that curves along the outer circumferential surface of the operating shaft.

6. An outer frame that is fitted into the opening of the building, an inner frame that takes a closed position located inside the outer frame and an open position that is removed from the outer frame; The locking mechanism according to any one of claims 1 to 5, A building inspection hatch having a

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