Method for constructing stairs

Abstract

To provide a method for constructing stairs capable of easily positioning each part of stairs without performing stair layout work, and improving workability of the stairs.SOLUTION: In constructing stairs 1 according to design reference modules M inside a stair chamber 2 of a building designed by arranging a wall according to the modules M, the stairs 1 are constructed by building multiple types of stair configuring members starting from the floor, the multiple types of stair configuring members include one stair configuring member and the other stair configuring member provided consecutively to each other, a step for attaching the one stair configuring member to a predetermined position according to the modules and a step for attaching the other stair configuring member to a position that is continuous with the one stair configuring member are provided, one surface in the one stair configuring member attached to the predetermined position is taken as a ruler surface that may position the other stair configuring member according to the modules, and the other stair configuring member is arranged along the rule surface when attaching the same.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a method for constructing stairs.

Background Art

[0002] Conventionally, when constructing stairs in a building such as a house, after the building frame is assembled to a certain extent, the layout of the beam members and treads of the stairs is marked, and the stairs are constructed according to the marked positions. However, since the layout work not only takes time but also requires high accuracy, in recent years, the stairs have been unitized in a factory or the like in advance to significantly reduce the on-site work (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of a building frame constructed by a wooden frame construction method, it is difficult to avoid displacement from the design dimensions due to bending of the building frame, assembly dimension errors, etc., and eventually, layout work may be required.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to easily position each part of the stairs without performing layout work and improve the constructability of the stairs.

Means for Solving the Problems

[0006] In order to solve the above problems, the method for constructing a staircase according to the present invention is to construct a staircase according to the module inside a staircase room formed by a through-hole from a lower floor to an upper floor in a building designed by arranging walls according to a module serving as a design standard. The staircase room has a floor of the lower floor and a wall surface of the wall orthogonal to the floor of the lower floor. The staircase is constructed by assembling a plurality of types of staircase components from the floor. The plurality of types of staircase components include one staircase component and another staircase component provided continuously with each other. A step of attaching the one staircase component to a predetermined position according to the module. A step of attaching the other staircase component to a position continuous with the one staircase component. One side surface of the one staircase component attached to the predetermined position serves as a reference surface that can position the other staircase component according to the module. The other staircase component is arranged along the reference surface when it is attached.

Advantages of the Invention

[0007] According to the present invention, it is possible to easily position each part of the staircase without performing layout work, and the constructability of the staircase can be improved.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, although various technically preferable limitations are imposed on the embodiments described below for carrying out the present invention, the technical scope of the present invention is not limited to the following embodiments and illustrated examples. Note that the directions in the following embodiments and illustrated examples are set only for the convenience of explanation.

[0010] [Regarding the Outline of the Staircase and the Staircase Room] FIG. 1 is a plan sectional view showing a state in which the staircase 1 of the present embodiment is provided in the staircase room 2. The staircase 1 is a spiral staircase 1 having a turning portion for changing the traveling direction in the middle portion from the lower floor to the upper floor. In the present embodiment, the spiral staircase 1 is such that the direction at the start of going up and the direction when finishing going up are exactly opposite, and includes a lower floor straight portion 1a, a lower turning portion 1b, an upper turning portion 1c, and an upper floor straight portion 1d. Note that the turning portion is configured to go up from the right side to the left side in FIG. 1.

[0011] Further, the staircase room 2 communicates between the upper and lower floors in a building such as a house. The building structure is covered with a fireproof covering material 5, and the building structure constituting the staircase room 1 is also covered with the fireproof covering material 5. As the fireproof covering material 5, a 12.5 mm thick gypsum board is used in the present embodiment, but other types of fireproof covering materials 5 may be used. The building structure is constructed by a wooden frame construction method. Therefore, as shown in FIG. 1, the staircase room 2 is defined by columns 3 which are frame members arranged at regular intervals, intermediate columns 4 arranged in the center between adjacent columns 3, and a fireproof covering material 5 attached to the side surfaces of the staircase room 2 of these columns 3 and intermediate columns 4. Further, the square timber constituting the column 3 is 105 mm square. Therefore, the dimension from the center (core axis) of the column 3 to the surface of the fireproof covering material 5 attached to the surface of the column 3 is set to 65 mm.

[0012] Further, a column 3 is also provided at the center of the staircase room 2. Also, this central column 3 is arranged at an interval from a front-side column 3 (not shown) erected at the center of the front side of the staircase room 2. An intermediate column 4 (not shown) is arranged between these columns 3, and a fireproof covering material 5 is attached to the surfaces of the column 3 and the intermediate column 4. As a result, a handrail wall 6 composed of the column 3, the intermediate column 4, and the fireproof covering material 5 is formed from the center position to the front side of the staircase room 2. The staircase 1, which is a spiral staircase, is installed so as to wrap around such a handrail wall 6 (central column 3). The handrail wall 6 is set higher than the height of the staircase 1.

[0013] The central pillar 3 (3a) is arranged at equal intervals in the left - right direction with respect to the right pillar 3 (3b) and the left pillar 3 (3d), and is also arranged at equal intervals in the front - back direction with respect to the front pillar 3 and the rear pillar 3 (3c). Also, pillars 3 are arranged at the left - right inner - corner parts on the rear side in the staircase room 2. The intervals between the pillar 3 at the inner - corner part and the other pillars 3 adjacent on the wall line are also set at equal intervals. That is, the intervals in the front - back, left - right directions among the six pillars 3 shown in FIG. 1 are all in an equal state. It is assumed that a base angle member as a base for fixing the fire - resistant coating material 5 is attached to the pillar 3 at each inner - corner part.

[0014] The intervals of the respective pillars 3 as described above are based on the reference dimension (module: M) in building design. In this embodiment, 910 mm is defined as 1 module (M). More specifically, when designing the floor plan of a building, a reference line L which is the center line connecting the centers of pillars and walls is used, and the interval between parallel reference lines L is defined as 1 module. Since the pillar 3 is 105 mm square as described above, the center line passes through a position 52.5 mm from the surface of the pillar 3. In other words, the length from the center line of the pillar 3 to the surface of the pillar 3 is 52.5 mm. When a 12.5 - mm - thick fire - resistant coating material 5 is attached to the surface, the length from the center line of the pillar 3 to the surface of the fire - resistant coating material 5 becomes 65 mm.

[0015] Also, the staircase room 2 has a rough floor surface 7 before the floor finishing material such as a flooring material is constructed, and the staircase 1 is installed on the upper surface of this rough floor surface 7. Also, the upper end part of the staircase 1 is connected to the upper - floor floor 9 provided on the upper - floor beam 8. In FIG. 3, the arrow A shown on the rough floor surface 7 indicates the upward direction of the spiral staircase 1.

[0016] 〔Regarding the staircase construction set〕 FIG. 2 shows a staircase construction set in which all the components used for constructing the spiral staircase 1 in a building such as a wooden house are assembled. The set for step - by - step construction includes a jig bar set 10 containing a plurality of jig bars (bar - shaped jigs), a spacer set 20 containing a plurality of spacers, a surrounding receiving member set 30 containing a plurality of surrounding receiving members (receiving members: inner - surrounding receiving members, outer - surrounding receiving members), a side girder set 40 containing a plurality of side girders (lower - floor side girders, upper - floor side girders), a surrounding step board set 50 containing a plurality of surrounding step boards and a plurality of decorative kick - in boards, etc., a step board set 60 containing a plurality of step boards and a plurality of decorative kick - in boards, etc., a top - most frame set 70 containing a top - most frame and a top - most frame support, a bottom - most kick - in board set 80 containing a kick - in board for the bottom - most step, etc., and a staircase width board set 90 containing a plurality of staircase width boards.

[0017] (Jig bar set) First, the jig bar set 10 includes a first jig bar 11, a second jig bar 12, a third jig bar 13, a fourth jig bar 14, a fifth jig bar 15, and a sixth jig bar 16. These plurality of jig bars 11 - 16 are composed of square bars set to a plurality of lengths and are used in a state of standing vertically in the up - down direction. Also, as shown in FIG. 3, these plurality of jig bars 11 - 16 are fixed to the building's frame by fixing materials such as screws.

[0018] The first jig bar 11 and the second jig bar 12 are set to the same length (height). And the first jig bar 11 is screw - fixed to the central column 3a through the fire - resistant coating material 5 on the back side. As shown in FIG. 4, the lower end of the first inner - surrounding receiving member 31 is placed on the upper end surface of this first jig bar 11. The second jig bar 12 is arranged at a position shifted 93 mm backward from the center of the column 3b adjacent to the right side of the central column 3a and is screw - fixed to the frame side. A base for screw - fixing (such as a stud 4, a base - angle material, etc.) may be incorporated on the frame side. Also, as shown in FIG. 5, etc., the downward - protruding portion 33b of the first outer - surrounding receiving member 33 arranged in the lower - surrounding portion 1b is placed on the upper end surface of this second jig bar 12. Also, this second jig bar 12 functions as a positioning means for the right - hand lower - floor side girder 41. Details of the positioning means will be described later.

[0019] The third jig bar 13 is set to be longer (higher) than the first jig bar 11 and the second jig bar 12. Then, it is placed closely against the right inner corner on the back side and is screwed to the base angle member attached to the column 3 at the right inner corner through the refractory coating material 5. Also, on the upper end surface of this third jig bar 13, as shown in FIG. 5 etc., the upper end part of the first outer circumferential receiving member 33 arranged in the lower circumferential part 1b and the lower end part of the second outer circumferential receiving member 34 are placed in a connected state.

[0020] The fourth jig bar 14 is set to be longer (higher) than the third jig bar 13. Then, it is screwed to the column 3c on the back through the refractory coating material 5 on the back side. Note that the first jig bar 11 and the fourth jig bar 14 are arranged on the same reference line L and face each other. Also, on the upper end surface of this fourth jig bar 14, as shown in FIG. 5 etc., the upper end part of the second outer circumferential receiving member 34 arranged in the lower circumferential part 1b is placed.

[0021] The fifth jig bar 15 is set to be longer (higher) than the fourth jig bar 14. Then, it is placed closely against the left inner corner on the back side and is screwed to the base angle member attached to the column 3 at the left inner corner through the refractory coating material 5. Also, on the upper end surface of this fifth jig bar 15, as shown in FIG. 5 etc., the upper end part of the first outer circumferential receiving member 33 arranged in the upper circumferential part 1c and the lower end part of the second outer circumferential receiving member 34 are placed in a connected state.

[0022] The sixth jig bar 16 is set to be longer (higher) than the fifth jig bar 15. Then, it is arranged in alignment with the center of 3d adjacent to the left side of the central column 3a, and the back side surface of the sixth jig bar 16 is arranged in alignment with the center (the position of the reference line L) of the left column 3d. Also, on the upper end surface of this sixth jig bar 16, as shown in FIG. 5 etc., the upper end part of the second outer circumferential receiving member 34 arranged in the upper circumferential part 1c is placed.

[0023] (Fitting set) Subsequently, the fitting set 20 includes a plurality of fittings 21. These fittings 21 are all rectangular plates set to the same size, with the longitudinal dimension set to 150 mm and the transverse dimension set to 93 mm. Also, the thickness dimension is not particularly limited but is set to about 10 - 30 mm.

[0024] As shown in FIG. 14, the fitting 21 is used to press and fix the decorative kick-in plate 54 attached directly below the spiral treads 51, 52, 53 to the lower spiral treads 51, 52, 53 or the rectangular tread 61 side.

[0025] Also, as shown in FIGS. 3 and 6, the fitting 21 is used for positioning the second jig bar 12. That is, the positioning of the second jig bar 12, which functions as a positioning means for the right lower floor side girder 41, can be performed using the width dimension of the fitting 21. The positioning operation of the second jig bar 12 will be described later.

[0026] (Spiral receiving member set) Subsequently, the spiral receiving member set 30 includes a first inner spiral receiving member 31 and a second inner spiral receiving member 32 provided on the inner peripheral side (center side) in the spiral direction, and a first outer spiral receiving member 33 and a second outer spiral receiving member 34 provided on the outer peripheral side in the spiral direction. The first inner spiral receiving member 31 and the second inner spiral receiving member 32 are arranged vertically and fixed to the end of the handrail wall 6 with screws. There are two sets of the first outer spiral receiving member 33 and the second outer spiral receiving member 34. The first set of the first outer spiral receiving member 33 and the second outer spiral receiving member 34 are arranged closely against the right entrance corner on the back side of the staircase room 2 with their ends connected in the orthogonal direction and fixed with screws. The second set of the first outer spiral receiving member 33 and the second outer spiral receiving member 34 are arranged closely against the left entrance corner on the back side of the staircase room 2 with their ends connected in the orthogonal direction and fixed with screws. On the upper surface of the upper end of the second outer spiral receiving member 34 of the first set, the downward protruding portion 33b of the first outer spiral receiving member 33 of the second set is placed.

[0027] Since the first inner circumferential receiving member 31 and the second inner circumferential receiving member 32 have the same shape except for the different mounting directions, the description of the shape of the second inner circumferential receiving member 32 will be simplified.

[0028] As shown in FIGS. 2, 4, etc., the first inner circumferential receiving member 31 includes a first side plate portion 31a that is applied to the right side surface at the end of the handrail wall 6, and a second side plate portion 31b that is applied to the back surface at the end of the handrail wall 6. The first side plate portion 31a and the second side plate portion 31b are integrally formed in a state of being orthogonal to each other in a plan view. The first side plate portion 31a is formed in a rectangular shape. On the other hand, the second side plate portion 31b is formed in a stepped shape where the side closer to the first side plate portion 31a is lower and the side opposite to the first side plate portion 31a is higher. The upper end surface of the first side plate portion 31a is located below the upper end surface of the lower step in the second side plate portion 31b. Also, the lower end surfaces of the first side plate portion 31a and the second side plate portion 31b are flush.

[0029] Also, on each of the step plate side surface of the upper end portion of the first side plate portion 31a, the step plate side surface of the upper end portion of the lower step in the second side plate portion 31b, and the step plate side surface of the upper end portion of the higher step in the second side plate portion 31b, there are attached step plate fixing bars 31c on which the circumferential step plates 51, 52, 53 are placed and fixed.

[0030] And such a first inner circumferential receiving member 31 is screwed to the back side of the handrail wall 6 in a state of being placed on the upper end surface of the first jig bar 11 screwed to the back side of the handrail wall 6 as shown in FIGS. 4, etc. At this time, the first side plate portion 31a is in contact with the right side surface of the end of the handrail wall 6, and the second side plate portion 31b is screwed in a state of being in contact with the back surface of the end of the handrail wall 6.

[0031] In addition, the thickness dimensions of the first side panel portion 31a and the second side panel portion 31b are set to 28 mm. Since the dimension from the center of the column 3a disposed at the end of the handrail wall 6 to the surface of the fire-resistant coating material 5 attached to the surface of the column 3a is set to 65 mm, the dimension from the center of the column 3a to the surfaces of the first side panel portion 31a and the second side panel portion 31b will be set to 93 mm.

[0032] Since the second inner circumferential receiving member 32 also has the same shape as the first inner circumferential receiving member 31, it includes a first side panel portion 32a and a stepped second side panel portion 32b, and a step plate fixing bar 31c is attached to each step plate side surface. Then, as shown in FIG. 4 and the like, such a second inner circumferential receiving member 32 is screwed and fixed to the end of the handrail wall 6 in a state of being placed on the upper end surface of the first inner circumferential receiving member 31. At this time, the first side panel portion 32a is in contact with the back surface of the end of the handrail wall 6, and the second side panel portion 32b is screwed and fixed in a state of being in contact with the left side surface of the end of the handrail wall 6.

[0033] The first outer circumferential receiving member 33 includes a lower side, an upper side located above the lower side, and a connecting side connecting one end of the lower side and the other end of the upper side, and is a plate material formed in a crank shape in side view. The overall length of the first outer circumferential receiving member 33 corresponds to 1M (module) of the reference dimension. Therefore, both ends in the length direction can be screwed and fixed to the column 3. The upper side has a lower connecting portion 33a formed by notching the upper half of one end of the upper side. The upper connecting portion 34a of the other end of the lower side of the second outer circumferential receiving member 34 to be described later is connected to the lower connecting portion 33a. The lower side has a downward protruding portion 33b integrally formed at the other end of the lower side and protruding downward. This downward protruding portion 33b is for arranging the circumferential step plate 51 at an appropriate height position, and its protruding dimension is based on the design dimension of the first step 1. Such a downward protruding portion 33b functions as a positioning means for the right lower floor side girder 41. Further, on each of the step plate side surfaces of the upper edge portions on the lower side and the upper side, there is attached a step plate fixing bar 33c on which the surrounding step plates 51, 52, 53 are placed and fixed.

[0034] The second outer surrounding receiving member 34 includes a lower side, an upper side located above this lower side, and a connecting side connecting one end of the lower side and the other end of the upper side, and is a plate material formed to have a crank shape in a side view. The overall length of the second outer surrounding receiving member 34 is a dimension corresponding to 1M of the reference dimension. Therefore, it is easy to fix both ends in the length direction to the column 3 with screws. The lower side has an upper connecting portion 34a formed by notching the lower half of the other end portion on the lower side. To this upper connecting portion 34a, a lower connecting portion 33a at one end on the upper side of the first outer surrounding receiving member 33 is connected. That is, the upper connecting portion 34a of the second outer surrounding receiving member 34 is placed and fitted on the upper surface of the lower connecting portion 33a of the first outer surrounding receiving member 33. In the present embodiment, these lower connecting portion 33a and upper connecting portion 34a are simply in a fitted state, but it is not limited to this, and they may be joined with an adhesive or screwed. Further, on each of the step plate side surfaces of the upper edge portions on the lower side and the upper side, there is attached a step plate fixing bar 34c on which the surrounding step plates 51, 52, 53 are placed and fixed.

[0035] And this second outer surrounding receiving member 34 is arranged in a direction orthogonal to the first outer surrounding receiving member 33 in a plan view. Therefore, the lower connecting portion 33a of the first outer surrounding receiving member 33 of the first set and the upper connecting portion 34a of the second outer surrounding receiving member 34 are arranged at the right entrance corner on the back side of the staircase room 2 in a state of being connected in the orthogonal direction. The lower connecting portion 33a of the first outer surrounding receiving member 33 of the second set and the upper connecting portion 34a of the second outer surrounding receiving member 34 are arranged at the left entrance corner on the back side of the staircase room 2 in a state of being connected in the orthogonal direction. In addition, the step plate fixing bar 33c provided on the upper side of the first outer circumferential receiving member 33 and the step plate fixing bar 34c provided on the lower side of the second outer circumferential receiving member 34 are arranged at positions where they do not interfere with each other when the first outer circumferential receiving member 33 and the second outer circumferential receiving member 34 are arranged perpendicular to each other in a plan view. At this time, the kicking fixing bar 55 and the stop log 21 may also be arranged at positions where they do not interfere with each other. That is, the step plate fixing bar 33c, the step plate fixing bar 34c, the kicking fixing bar 55, and the stop log 21 may be arranged at positions where they do not interfere with each other. Further, the step plate fixing bar 33c and the step plate fixing bar 34c adjacent to each other in the orthogonal direction have the same height position on the upper surface. Furthermore, as described above, on the upper surface of the upper end portion of the first set of second outer circumferential receiving members 34, the downward protruding portion 33b of the second set of first outer circumferential receiving members 33 is placed. In such a state where the two sets of receiving members are continuous, the height differences of the step plate fixing bars 33c and 34c of each step are equal.

[0036] (Side girder set) Subsequently, the side girder set 40 includes a pair of lower floor side girders 41 and a pair of upper floor side girders 42 that support the rectangular step plate 61 in the straight portion of the spiral staircase 1. The pair of lower floor side girders 41 are provided in the lower floor straight portion 1a of the spiral staircase 1, and the pair of upper floor side girders 42 are provided in the upper floor straight portion 1d of the spiral staircase 1. These lower floor side girders 41 and upper floor side girders 42 are so-called sazara girders with their upper edges notched in a zigzag shape like a staircase as shown in FIGS. 2, 6, 16, etc., and by being notched in this way, they are provided with a plurality of stepped portions. The lower edges of the lower floor side girders 41 and upper floor side girders 42 extend obliquely in a straight line along the ascending and descending directions of the staircase 1. Each of the plurality of stepped portions of the lower floor side girders 41 and upper floor side girders 42 has a horizontal first surface on which the rectangular step plate 61 is placed and a vertical second surface along the decorative kicking plate 62. And on the side surface of the staircase 1 at the upper end portion of each stepped portion, step plate fixing bars 41b and 42b on which the rectangular step plate 61 is placed and fixed are attached, and the upper surfaces of these step plate fixing bars 41b and 42b and the first surface of each stepped portion are flush. In addition, the pair of lower floor side girders 41 and the pair of upper floor side girders 42 are fixed to the building body side (columns 3, 3a, 3b, and intermediate columns 4) with screws.

[0037] Further, a vertical surface 41a perpendicular to the first surface of the uppermost step portion is formed at the upper end portion of the lower-side beam 41. In other words, when the lower-side beam 41 is installed at a predetermined position in the staircase chamber 2, the vertical surface 41a is formed by vertically cutting the end portion closest to the surrounding portion. As shown in FIG. 6(b), this vertical surface 41a is arranged to be flush with the surface of the second side plate portion 31b of the first inner surrounding receiving member 31 provided at the end portion of the handrail wall 6.

[0038] That is, when installing the left lower-side beam 41 (on the handrail wall 6 side) of the pair of lower-side beams 41 in the staircase chamber 2 and fixing it to the housing, the surface of the second side plate portion 31b of the first inner surrounding receiving member 31 provided at the end portion of the handrail wall 6 is used as a straight-edge surface (reference surface), and the vertical surface 41a of the lower-side beam 41 is aligned with that surface so as to be flush. Then, when the lower-side beam 41 is fixed to the housing side at the position thus aligned, the lower-side beam 41 will be arranged at the designed position. At this time, the dimension from the position of the front-end face on the front side of the first side plate portion 31a of the first inner surrounding receiving member 31 to the front-end portion of the uppermost step portion of the lower-side beam 41 is equal to the length dimension of the first surface (horizontal plane of the upper surface) of the other step portions. In other words, it corresponds to the depth dimension of the rectangular step plate 61 to be placed.

[0039] Further, when the pair of lower-side beams 41 are installed, the height dimension from the lower end face to the upper end face of the pair of lower-side beams 41 is set to be equal to the height dimensions of the first jig bar 11 and the second jig bar 12.

[0040] On one hand, when installing the lower floor side beam 41 on the right side (opposite to the handrail wall 6) of the pair of lower floor side beams 41 in the staircase room 2 and fixing it to the building body, use the front side surface of the upper end of the second jig bar 12 as the reference surface (datum surface), and make the vertical surface 41a of the lower floor side beam 41 contact exactly with this surface. Further, make the upper end surface of this lower floor side beam 41 contact exactly with the lower end surface of the downward protruding part 33b of the first outer surrounding receiving member 33. Then, when fixing the lower floor side beam 41 to the building body side at the position aligned in this way, the lower floor side beam 41 will be arranged at the designed position. That is to say, the second jig bar 12 and the first outer surrounding receiving member 33 will function as the positioning means for the right lower floor side beam 41 as described above. In addition, as described above, the second jig bar 12 itself is positioned by the spacer 21 and arranged at the designed position. To explain in more detail, since the width dimension of the spacer 21 is set to 93 mm, when the spacer 21 is applied to the right side surface of the staircase room 2 and, as shown in Fig. 3(b), align one side surface (front end surface) in the width direction of the spacer 21 with the center line (reference line L) of the right column 3b, the other side surface (rear end surface) in the width direction will be arranged at a position 93 mm from the center line (reference line L) of the right column 3b. Then, after making the front side surface of the second jig bar 12 contact exactly with the other side surface in the width direction of this spacer 21 and fixing the second jig bar 12 to the building body side, even if the spacer 21 is removed, the front side surface of the second jig bar 12 will be arranged at a position 93 mm from the center line (reference line L) of the right column 3. Therefore, just by making the vertical surface 41a of the right lower floor side beam 41 contact exactly with the front side surface of the second jig bar 12 and then fixing it to the building body, the right lower floor side beam 41 will be arranged at the designed position.

[0041] Furthermore, since the central column 3a and the right column 3b are arranged on the same reference line L, the rear side surfaces of both will also be arranged on the same vertical plane. And since the vertical surfaces 41a of the pair of lower floor side beams 41 are both arranged at a position 93 mm from the centers of the columns 3a and 3b, the pair of lower floor side beams 41 will be arranged facing each other at the designed positions without particularly performing layout work.

[0042] Next, the upper floor side girder 42 will be described. At the upper end of the upper floor side girder 42, as shown in FIGS. 2 and 16 etc., an upward protruding portion 42a is integrally formed with a slight gap left between it and the side surface of the upper floor beam 8. More specifically, the upward protruding portion 42a is formed in a prismatic shape, and the front side surface is provided with a slight gap left between it and the end faces of the upper floor beam 8 and the upper floor slab 9. The upper end surfaces of the upward protruding portions 42a of the pair of upper floor side girders 42 arranged in this way are horizontal. Also, between the upward protruding portions 42a of the pair of upper floor side girders 42, the uppermost sill receiving member 72 described later is arranged. Then, the uppermost sill 71 is placed and fixed on the upper end surfaces of these upward protruding portions 42a and the upward facing surface in the notch portion 72a of the uppermost sill receiving member 72.

[0043] Of the pair of upper floor side girders 42, the right upper floor side girder 42 has its lower end placed on the higher step (the upper end surface of the second inner circumferential receiving member 32) of the second side plate portion 31b in the second inner circumferential receiving member 32 and is screwed to the building body. That is, it is screwed to the handrail wall 6 (the central pillar 3a, the intermediate pillar 4, the front pillar 3). Also, of the pair of upper floor side girders 42, the left upper floor side girder 42 has its lower end placed on the upper side front end upper surface of the second outer circumferential receiving member 34 in the second circumferential receiving member set and is screwed to the building body. That is, it is screwed to the left side surface of the staircase room 2 (the left pillar 3d, the intermediate pillar 4, the front pillar 3).

[0044] (Circular step plate set) Subsequently, as shown in FIGS. 7 to 11, FIG. 13, FIG. 14 etc., the circular step plate set 50 includes a plurality of circular step plates 51, 52, 53 provided at the circular portion of the staircase 1, and a plurality of decorative kick-in plates 54 and a plurality of kick-in fixing bars 55 fixed below the step noses of these plurality of circular step plates 51, 52, 53. Two sets of the plurality of circular step plates 51, 52, 53, the plurality of decorative kick-in plates 54 and the plurality of kick-in fixing bars 55 are included. The first set of the surrounding step plates 50 is fixed and supported with respect to the first inner surrounding receiving member 31 that constitutes the lower surrounding portion 1b of the surrounding portion of the staircase 1, the first outer surrounding receiving member 33, and the second outer surrounding receiving member 34. The second set of the surrounding step plates 50 is fixed and supported with respect to the second inner surrounding receiving member 32 that constitutes the upper surrounding portion 1c of the surrounding portion of the staircase 1, the first outer surrounding receiving member 33, and the second outer surrounding receiving member 34.

[0045] The plurality of surrounding step plates 51, 52, 53 include the lower first surrounding step plate 51, the middle second surrounding step plate 52, and the upper third surrounding step plate 53. As shown in FIG. 7(b), these plurality of surrounding step plates 51, 52, 53 are shaped to become thinner as they go toward the portion arranged on the center side (inner peripheral side) in the surrounding portion of the staircase 1 in plan view.

[0046] More specifically, among the surrounding step plates 51, 52, 53, the portion arranged on the center side (inner peripheral side) in the surrounding portion of the staircase 1 is processed to have a shape that matches the end of the handrail wall 6. Therefore, the shapes of the portions arranged on the center side (inner peripheral side) of each of the surrounding step plates 51, 52, 53 are different from each other. That is, the portion on the center side of the lower first surrounding step plate 51 is formed linearly so as to fit exactly with one surface (right side surface or back side surface) of the handrail wall 6. Also, the portions on the center side of the middle second surrounding step plate 52 and the upper third surrounding step plate 53 are notched in an L shape so as to fit exactly with two orthogonal surfaces of the handrail wall 6.

[0047] Also, among the surrounding step plates 51, 52, 53, the portion arranged on the outer peripheral side in the surrounding portion of the staircase 1 has a shape along the wall surface of the staircase room 2. That is, the portion arranged on the outer peripheral side of the middle second surrounding step plate 52 is formed at a right angle so as to fit exactly into the entrance corner portion of the staircase room 2. Also, the portions on the outer peripheral side of the lower first surrounding step plate 51 and the upper third surrounding step plate 53 are formed linearly so as to fit exactly with the wall surface of the staircase room 2.

[0048] Note that the dimensions of each circumferential step plate 51, 52, 53 in the width direction (the direction orthogonal to the elevating direction of the staircase 1) need to be such that they can fit between the handrail wall 6 of the staircase room 2 and the outer peripheral wall surface. Therefore, the width dimensions of each circumferential step plate 51, 52, 53 are appropriately adjusted on-site. In that case, if the central part is to be processed, fine adjustment is required. Therefore, as shown by the dashed line in Fig. 7(b), the outer peripheral part is appropriately cut to adjust the width dimension.

[0049] Insertion grooves 51a, 52a, 53a into which the upper ends of the decorative kick-in plates 54 are inserted are formed on the lower surfaces of the step nose portions of each circumferential step plate 51, 52, 53. The insertion grooves 51a, 52a, 53a are formed along the width direction (the direction orthogonal to the elevating direction of the staircase 1) in the step nose portions of each circumferential step plate 51, 52, 53. The width dimension of the decorative kick-in plate 54 is set to be substantially equal to the width dimension in the width direction of the step nose portion of each circumferential step plate 51, 52, 53. The lengths of the respective insertion grooves 51a, 52a, 53a are also set to be substantially equal. The groove width of each insertion groove 51a, 52a, 53a is set to be longer than the thickness dimension of the decorative kick-in plate 54.

[0050] A kick-in fixing bar 55 is fixed to the back surface (the surface opposite to the decorative surface) at the upper end of the decorative kick-in plate 54. Therefore, the decorative kick-in plate 54 and the kick-in fixing bar 55 may be handled as one member. The decorative kick-in plate 54 and the kick-in fixing bar 55 provided integrally in this way are in a state where the upper end of the decorative kick-in plate 54 protrudes slightly above the upper surface of the kick-in fixing bar 55. The protruding dimension of the upper end of the decorative kick-in plate 54 is set to be substantially equal to the groove depth of each insertion groove 51a, 52a, 53a. Therefore, as shown in Fig. 7(c) etc., when the upper end of the decorative kick-in plate 54 is inserted into each insertion groove 51a, 52a, 53a, the upper surface of the kick-in fixing bar 55 comes into contact with the lower surfaces of each circumferential step plate 51, 52, 53. Then, the kick-in fixing bar 55 is screwed to the lower surfaces of each circumferential step plate 51, 52, 53.

[0051] When constructing the second circumferential step plate 52 in the middle section and the third circumferential step plate 53 in the upper section, for the decorative kick-in plate 54, as shown in FIGS. 8 to 11, FIG. 13, FIG. 14, etc., the lower end portion thereof is sandwiched between the kick-in side end portions of the circumferential step plates 51 and 52 located below and the respective circumferential receiving members 31 to 34. Also, the lower end portion of the decorative kick-in plate 54 is fixed to the kick-in side end faces of the respective circumferential step plates 51, 52, and 53 with screws.

[0052] The plurality of circumferential step plates 51, 52, and 53 are respectively fixed to the first inner circumferential receiving member 31, the second inner circumferential receiving member 32, the first outer circumferential receiving member 33, and the second outer circumferential receiving member 34. More specifically, each of the circumferential step plates 51, 52, and 53 is placed on the step plate fixing bars 31c, 32c, 33c, and 34c of the respective circumferential receiving members 31, 32, 33, and 34. Then, the step plate fixing bars 31c, 32c, 33c, and 34c of the respective circumferential receiving members 31, 32, 33, and 34 are fixed to the lower surfaces of the respective circumferential step plates 51, 52, and 53 with screws.

[0053] The construction of the plurality of circumferential step plates 51, 52, and 53 is carried out starting from the first circumferential step plate 51 in the lower section. Next, the second circumferential step plate 52 in the middle section is constructed, and then the third circumferential step plate 53 in the upper section is constructed. Also, for the circumferential step plate set 50, the construction of the first set on the lower side is carried out, and then the construction of the second set on the upper side is carried out. That is, the construction of the plurality of circumferential step plates 51, 52, and 53 is carried out from the bottom to the top of the staircase 1. Note that the construction of the first set of the circumferential step plate set 50 is carried out prior to the construction of the step plate set 60 including the plurality of rectangular step plates 61.

[0054] Note that the plurality of circumferential step plates 51, 52, and 53 in the present embodiment are made of MDF (Medium Density Fiberboard), which is a medium-density fiberboard formed by fibrillating wood raw chips into powder and then molding them. Also, the thickness dimension of the plurality of circumferential step plates 51, 52, and 53 is set to about 30 mm.

[0055] (Step plate set) Subsequently, as shown in FIGS. 12, 17, etc., the step board set 60 includes a plurality of rectangular step boards 61 provided on the lower straight portion 1a and the upper straight portion 1d of the staircase 1, and a plurality of decorative kicking-in boards 62 and a plurality of kicking-in fixing bars 63 fixed below the step noses of each of these plurality of rectangular step boards 61. The plurality of rectangular step boards 61, the plurality of decorative kicking-in boards 62, and the plurality of kicking-in fixing bars 63 include the number of steps corresponding to the plurality of steps other than the turning portion.

[0056] The rectangular step board 61 is formed in a rectangular shape in plan view, and an insertion groove 61a into which the upper end portion of the decorative kicking-in board 62 is inserted is formed on the lower surface of the step nose portion of each rectangular step board 61. The insertion groove 61a is formed along the width direction (the direction orthogonal to the ascending and descending direction of the staircase 1) of the step nose portion of each rectangular step board 61. The width dimension of the decorative kicking-in board 62 is set to be substantially equal to the width dimension in the width direction of the step nose portion of the rectangular step board 61. The length of the insertion groove 61a is also set to be substantially equal. The groove width of each insertion groove 61a is set to be longer than the thickness dimension of the decorative kicking-in board 62.

[0057] The kicking-in fixing bar 63 is fixed to the back surface (the surface opposite to the decorative surface) at the upper end portion of the decorative kicking-in board 62. Therefore, the decorative kicking-in board 62 and the kicking-in fixing bar 63 may be handled as one member. The decorative kicking-in board 62 and the kicking-in fixing bar 63 provided integrally in this way are in a state where the upper end portion of the decorative kicking-in board 62 protrudes slightly above the upper surface of the kicking-in fixing bar 63. The protruding dimension of the upper end portion of the decorative kicking-in board 62 is set to be substantially equal to the groove depth of the insertion groove 61a of the rectangular step board 61. Therefore, as shown in FIG. 12(b), etc., when the upper end portion of the decorative kicking-in board 62 is inserted into the insertion groove 61a, the upper surface of the kicking-in fixing bar 63 comes into contact with the lower surface of the rectangular step board 61. Then, the kicking-in fixing bar 63 is screwed and fixed to the lower surface of the rectangular step board 61. Note that the kicking-in fixing bar 63 is arranged such that in a cross-sectional view, the depth dimension of the horizontal plane (upper surface, lower surface) is longer than the height dimension of the vertical plane. In the fixing operation to the decorative kicking-in board 62, screw fixing is performed from the lower surface side. That is, since a wide surface can be used as the screw fixing surface, screw fixing becomes easy. That is, a square bar with a rectangular cross-section is used for the kicking-in fixing bar 63, and the wide surface is used as the screw fixing surface.

[0058] As shown in FIG. 12 and the like, the plurality of rectangular stepped plates 61 are placed on the horizontal first surface of each step portion of the lower floor side girder 41 in the lower floor straight portion 1a, and are also placed on the upper surface of the step plate fixing bar 41b that is flush with the first surface. Then, the step plate fixing bar 41b at each step portion of the lower floor side girder 41 is screw-fixed to the lower surface of each rectangular stepped plate 61. Further, the decorative kicking-in board 62 is provided along the vertical second surface at each step portion of the lower floor side girder 41. In the present embodiment, it is assumed that the decorative kicking-in board 62 is in close contact with the vertical second surface at each step portion of the lower floor side girder 41.

[0059] As shown in FIG. 17 and the like, the plurality of rectangular stepped plates 61 are placed on the horizontal first surface of each step portion of the upper floor side girder 42 in the upper floor straight portion 1d, and are also placed on the upper surface of the step plate fixing bar 42b that is flush with the first surface. Then, the step plate fixing bar 42b at each step portion of the upper floor side girder 42 is screw-fixed to the lower surface of each rectangular stepped plate 61. Further, the decorative kicking-in board 62 is provided along the vertical second surface at each step portion of the upper floor side girder 42. In the present embodiment, it is assumed that the decorative kicking-in board 62 is in close contact with the vertical second surface at each step portion of the upper floor side girder 42.

[0060] In the lower floor straight portion 1a of the staircase 1, the plurality of rectangular stepped plates 61 are constructed in order from the top, excluding the lowermost rectangular stepped plate 61. Note that the lowermost rectangular stepped plate 61 is constructed in a later process. When constructing a plurality of rectangular step plates 61 in the lower straight portion 1a, the decorative kicking-in plate 62 has its lower end portion sandwiched between the kicking-in side end portion of the rectangular step plate 61 located below and the vertical second surface at each step portion of the lower floor side girder 41. Also, the lower end portion of the decorative kicking-in plate 62 is screwed to the kicking-in side end surface of the rectangular step plate 61 located below. Note that the lower end portion of the decorative kicking-in plate 54 fixed to the first surrounding step plate 51 located above is screwed to the kicking-in side end surface of the rectangular step plate 61 located most upward in the lower straight portion 1a.

[0061] In the upper straight portion 1d of the staircase 1, a plurality of rectangular step plates 61 are constructed in order from the bottom. When constructing a plurality of rectangular step plates 61 in the upper straight portion 1d, the decorative kicking-in plate 62 has its lower end portion sandwiched between the kicking-in side end portion of the rectangular step plate 61 located below and the vertical second surface at each step portion of the upper floor side girder 42. Also, the lower end portion of the decorative kicking-in plate 62 is screwed to the kicking-in side end surface of the rectangular step plate 61 located below. Note that the lower end portion of the decorative kicking-in plate 62 located most downward in the upper straight portion 1d may be screwed to the kicking-in side end surface of the third surrounding step plate 53 located below it.

[0062] Note that the plurality of rectangular step plates 61 in this embodiment are composed of MDF (Medium Density Fiberboard), which is a medium-density fiberboard formed by fiberizing wood raw chips into powder and then molding them. Also, the thickness dimension of the plurality of rectangular step plates 61 is set to about 30 mm.

[0063] (Topmost frame set) Subsequently, as shown in FIGS. 15 to 18 and the like, the topmost frame set 70 includes a topmost frame 71 provided at the staircase 1 side end portion of the upper floor 9 corresponding to the topmost step of the staircase 1, and a topmost frame receiving wood 72 that supports the topmost frame 71.

[0064] On the lower surface of the portion corresponding to the stepped nose portion in the uppermost frame 71, an insertion groove 71a into which the upper end portion of the decorative kick-in plate 62 is inserted is formed. The insertion groove 71a is formed along the length direction of the uppermost frame 71. The width dimension of the decorative kick-in plate 62 is set to be substantially equal to the dimension in the length direction of the uppermost frame 71. The length of the insertion groove 71a is also set to be substantially equal. The groove width of the insertion groove 71a is set to be longer than the thickness dimension of the decorative kick-in plate 62. And, as shown in FIG. 18(b), the decorative kick-in plate 62 is integrally formed by inserting the upper end portion into the insertion groove 71a of the uppermost frame 71 and being fixed with screws.

[0065] The uppermost frame 71 is formed in a stepped shape having a notch portion 71b formed by notching the upper surface at the edge on the upper floor 9 side in an L shape. An end portion of the floor finishing material 9a laid on the upper surface of the upper floor 9 is arranged in the notch portion 71b. That is, the notch portion 71b functions as a housing portion for the end portion on the staircase 1 side of the floor finishing material 9a. Note that the upper surface of the uppermost frame 71 and the upper surface of the floor finishing material 9a are substantially flush.

[0066] The uppermost frame receiving timber 72 is formed in a stepped shape having a notch portion 72a formed by notching the edge on the staircase 1 side at the upper end portion in an L shape. The notch portion 72a includes a surface facing the staircase 1 side and an upward-facing surface. The uppermost frame 71 is placed on the upward-facing surface of this notch portion 72a, and furthermore, the end surface on the upper floor 9 side of the uppermost frame 71 is in contact with the surface facing the staircase 1 side. At this time, the upper end surface of the uppermost frame receiving timber 72 and the upward-facing surface in the notch portion 71b of the uppermost frame 71 are flush, and the floor finishing material 9a is laid on the upper surface as described above. That is, the end portion on the staircase 1 side of the floor finishing material 9a is arranged straddling the uppermost frame 71 and the uppermost frame receiving timber 72.

[0067] Such uppermost frame receiving beam 72 is arranged between upper protruding portions 42a on a pair of upper floor side girders 42 on the left and right as described above. And the uppermost frame 71 is placed and fixed on the upper end surfaces of these upper protruding portions 42a and the upward-facing surface in the notch portion 72a of the uppermost frame receiving beam 72. That is, the uppermost frame receiving beam 72 is set to have a shorter dimension than the uppermost frame 71. Also, the uppermost frame receiving beam 72 is set to have a shorter dimension than the distance between the upper protruding portions 42a on the pair of upper floor side girders 42. Therefore, the uppermost frame receiving beam 72 does not require on-site dimension adjustment, and neither measurement nor layout work is necessary, contributing to the improvement of the constructability of the staircase 1.

[0068] (Lowermost kicking board set) Subsequently, as shown in Fig. 19 etc., the lowermost kicking board set 80 includes a floor kicking fixing bar 81 fixed to the rough floor surface 7 of the lower floor, and a base plywood 82 and a lowermost decorative kicking board 83 that constitute the kicking surface at the lowermost stage of the staircase 1 including the floor kicking fixing bar 81.

[0069] And, as shown in Fig. 19, a kicking fixing bar 63 is pre-screwed to the lower surface of the lowermost rectangular step board 61. The upper edge portion of the base plywood 82 is screwed to the front portion of such a kicking fixing bar 63. This kicking fixing bar 63 is such that when the lowermost rectangular step board 61 is placed on the horizontal first surface at the lowermost step portion of a pair of lower floor side girders 41 and the step board fixing bar 41b of the pair of lower floor side girders 41 is screwed to the lower surface of the lowermost rectangular step board 61, the front portion of the kicking fixing bar 63 is flush with the end surfaces of the pair of lower floor side girders 41. Note that the length of this kicking fixing bar 63 is set to be approximately equal to the distance between the pair of lower floor side girders 41.

[0070] The floor kicking fixing bar 81 is arranged between the portions located on the most front side of a pair of lower floor side girders 41 and is screwed to the rough floor surface 7. And the lower edge portion of the base plywood 82 is screwed to the front portion of this floor kicking fixing bar 81. When this floor kicking-in fixing bar 81 is fixed to the rough floor surface 7, after being arranged so that the front surface of the floor kicking-in fixing bar 81 is flush with the end surfaces of the pair of lower-story side girders 41, it is fixed with screws. Further, the length of this floor kicking-in fixing bar 81 is set to be approximately equal to the interval between the pair of lower-story side girders 41. Therefore, the floor kicking-in fixing bar 81, the kicking-in fixing bar 63 fixed to the lower surface of the lowermost rectangular step board 61, and the end surfaces of the pair of lower-story side girders 41 are in a state of being formed in a rectangular frame shape. The base plywood 82 is fixed with screws to the portion formed in such a rectangular frame shape.

[0071] In this embodiment, the kicking-in fixing bar 63 fixed to the lower surface of the lowermost rectangular step board 61 and the floor kicking-in fixing bar 81 are set to be approximately equal to the interval between the pair of lower-story side girders 41, but it is not limited to this, and they may be set to be shorter than the interval between the pair of lower-story side girders 41 (they may be considerably shorter). That is, the kicking-in fixing bar 63 for the lowermost step and the floor kicking-in fixing bar 81 are set to be approximately equal to or shorter than the interval between the pair of lower-story side girders 41. If the lengths of the kicking-in fixing bar 63 for the lowermost step and the floor kicking-in fixing bar 81 are shorter than the interval between the pair of lower-story side girders 41, for example, even when the interval between the pair of lower-story side girders 41 becomes narrower due to variations in construction accuracy, etc., the kicking-in fixing bar 63 for the lowermost step and the floor kicking-in fixing bar 81 do not require on-site dimensional adjustment.

[0072] The decorative kicking-in board 83 for the lowermost step is a board material for decorating the kicking-in surface at the lowermost step of the staircase 1, and is set to be approximately equal to the vertical and horizontal dimensions of the base plywood 82. And such a decorative kicking-in board 83 for the lowermost step is joined to the surface of the base plywood 82 fixed with screws to the kicking-in surface at the lowermost step of the staircase 1 by an adhesive or the like.

[0073] (Stair nosing set) Subsequently, as shown in FIG. 20 and the like, the stair nosing set 90 includes a plurality of stair nosings 91 to 98 provided at the joining portion between the staircase 1 and the wall surface of the staircase room 2. The stair nosings 91 to 98 include various shapes according to the shape of the staircase 1. For example, the staircase skirting 91 is the same as the skirting provided at the joint between a normal floor and a wall, and is provided on the wall near the staircase 1. Also included are those having notches such as the staircase skirtings 92 to 97 into which the step noses of the respective treads 51, 52, 53, 61 and the decorative kick-in boards 54, 62 of the staircase 1 fit. Further included is that provided at the inner corner of the staircase 1, such as the staircase skirting 98.

[0074] [Regarding the construction method of the staircase] Subsequently, the construction method of the staircase 1 will be described. For the construction of the staircase 1, a jig bar set 10, a spacer set 20, a surrounding receiving member set 30, a side girder set 40, a surrounding tread set 50, a tread set 60, a topmost frame set 70, a bottommost kick-in board set 80, and a staircase skirting set 90 are used.

[0075] In the construction of the staircase 1, first, the construction of the staircase room 2 is carried out. The staircase room 2 is erected by arranging the intermediate columns 4 between a plurality of columns 3 erected based on a module which is a reference dimension, and a fireproof covering material 5 is attached to the side surface of the staircase room 2 of these columns 3 and intermediate columns 4 to define a space. Furthermore, a column 3a is erected at the center of the staircase room 2. Although not shown in the figure, an intermediate column 4 is erected between this column 3a and the front column 3, and a handrail wall 6 is constructed by attaching a fireproof covering material 5 around it. Thereby, the staircase room 2 can be made into a space for ascending the staircase 1 with the handrail wall 6 winding around. Note that in the staircase room 2 of the present embodiment, the right side of the handrail wall 6 is the upward entrance side (lower floor side) of the staircase 1, and the left side of the handrail wall 6 is the downward entrance side (upper floor side) of the staircase 1.

[0076] Next, as shown in Fig. 3(a), each of the jig bars 11 to 16 included in the jig bar set 10 is installed. First, the first jig bar 11 is applied to the center on the back surface of the handrail wall 6 and fixed to the central column 3a with screws through the fireproof covering material 5. That is, the first jig bar 11 will be arranged approximately at the center of the staircase room 2.

[0077] Subsequently, the second jig bar 12 is installed at a predetermined position by using the wooden block 21 of the wooden block set 20. To explain in more detail, the wooden block 21 with a width dimension set to 93 mm is applied to the right side surface of the staircase room 2, and as shown in FIG. 3(b), one side surface (front end surface) in the width direction of the wooden block 21 is arranged so as to align with the center line (reference line L) of the right pillar 3b. The wooden block 21 may be temporarily fixed to the right side surface of the staircase room 2. Then, the front side surface of the second jig bar 12 is brought into perfect contact with the other side surface (rear end surface) in the width direction of the wooden block 21, and the second jig bar 12 is fixed to the housing side with screws. At this time, the front side surface of the second jig bar 12 is arranged at a position 93 mm from the center line (reference line L) of the right pillar 3. The wooden block 21 is removed from the right side surface of the staircase room 2.

[0078] Subsequently, the third jig bar 13 is arranged in close contact with the right inner corner of the staircase room 2 and fixed with screws. At this time, the third jig bar 13 is fixed to the base angle member attached to the pillar 3 provided at the inner corner with screws.

[0079] Subsequently, the fourth jig bar 14 is placed in perfect contact with the center in the left - right direction on the rear side surface of the staircase room 2 and fixed to the rear pillar 3c with screws through the fire - resistant coating material 5. At this time, the fourth jig bar 14 is arranged so that its center (core axis) aligns with the center line (reference line L) of the rear pillar 3c.

[0080] Subsequently, the fifth jig bar 15 is arranged in close contact with the left inner corner of the staircase room 2 and fixed with screws. At this time, the fifth jig bar 15 is fixed to the base angle member attached to the pillar 3 provided at the inner corner with screws.

[0081] Subsequently, the sixth jig bar 16 is placed against the left side surface of the staircase room 2 and fixed to the left pillar 3d with screws through the fire - resistant coating material 5. At this time, the sixth jig bar 16 is arranged so that its rear side surface aligns with the center line (reference line L) of the left pillar 3d.

[0082] Next, as shown in FIGS. 4, 5, etc., a first inner circumferential receiving member 31 and a second inner circumferential receiving member 32 are attached to the back side end of the handrail wall 6. The first inner circumferential receiving member 31 and the second inner circumferential receiving member 32 have the same shape, but the mounting directions are different.

[0083] First, with the first inner circumferential receiving member 31 placed on the upper end surface of the first jig bar 11 fixed to the back side of the handrail wall 6, it is screwed to the back side end of the handrail wall 6. The first inner circumferential receiving member 31 is integrally formed with the first side plate portion 31a and the second side plate portion 31b orthogonal to each other in plan view. When screwing it to the back side end of the handrail wall 6, the first side plate portion 31a is applied to the right side surface of the end of the handrail wall 6, and the second side plate portion 31b is applied to the back surface of the end of the handrail wall 6. Then, the first side plate portion 31a and the second side plate portion 31b are each screwed to the central column 3a via the fireproof coating material 5.

[0084] Subsequently, with the second inner circumferential receiving member 32 placed on the upper end surface of the first inner circumferential receiving member 31, it is screwed to the back side end of the handrail wall 6. The second inner circumferential receiving member 32 is integrally formed with the first side plate portion 32a and the second side plate portion 32b orthogonal to each other in plan view. When screwing it to the back side end of the handrail wall 6, the first side plate portion 32a is applied to the back side surface of the end of the handrail wall 6, and the second side plate portion 32b is applied to the left side surface of the end of the handrail wall 6. Then, the first side plate portion 32a and the second side plate portion 32b are each screwed to the central column 3a via the fireproof coating material 5.

[0085] Next, as shown in FIG. 5, etc., two sets of a first outer circumferential receiving member 33 and a second outer circumferential receiving member 34 are attached to the side surface of the staircase room 2. The first outer circumferential receiving members 33 of each set and the second outer circumferential receiving members 34 of each set have the same shape, but the attachment locations and attachment directions are different.

[0086] First, the first outer circumferential receiving member 33 located in the lower circumferential portion 1b of the staircase 1 is tightly applied to and screwed to the right side surface of the staircase room 2 as shown in FIG. 5, etc. Incidentally, since the overall length of the first outer circumferential receiving member 33 corresponds to 1M (module) as described above, when the rear end portion of the first outer circumferential receiving member 33 is placed close to the right inner corner portion of the staircase chamber 2, the front end portion will reach the right pillar 3b. When screwing and fixing the first outer circumferential receiving member 33 of the lower circumferential portion 1b, the rear end face (the rear end face of the lower connecting portion 33a) is applied against the rear side surface of the staircase chamber 2, and further, the lower end face of the downward protruding portion 33b is placed against the upper end face of the second jig bar 12. At this time, the upper surfaces of the lower side and the upper side are horizontal. Also, as shown in FIG. 6(b), the front end portion of the downward protruding portion 33b protrudes to the front side from the front side surface of the second jig bar 12. When in such a state, both end portions of the first outer circumferential receiving member 33 are screwed and fixed to the right side surface of the staircase chamber 2.

[0087] Subsequently, as shown in FIG. 5 and the like, the second outer circumferential receiving member 34 located in the lower circumferential portion 1b of the staircase 1 is exactly applied against the rear side surface of the staircase chamber 2 and screwed and fixed. Incidentally, since the overall length of the second outer circumferential receiving member 34 also corresponds to 1M (module) which is the reference dimension, when the right end portion of the second outer circumferential receiving member 34 is placed close to the right inner corner portion of the staircase chamber 2, the right end portion will reach the rear pillar 3c. When screwing and fixing the second outer circumferential receiving member 34, the right end face (the right end face of the upper connecting portion 34a) is applied against the right side surface of the staircase chamber 2, and further, the left end portion is placed against the upper end face of the fourth jig bar 14. At this time, the upper surfaces of the lower side and the upper side are horizontal. Also, the left end portion protrudes to the right side from the fourth jig bar 14. When in such a state, both end portions of the second outer circumferential receiving member 34 are screwed and fixed to the rear side surface of the staircase chamber 2.

[0088] Subsequently, as shown in FIG. 5 and the like, the first outer circumferential receiving member 33 located in the upper circumferential portion 1c of the staircase 1 is exactly applied against the rear side surface of the staircase chamber 2 and screwed and fixed. And when the left end portion of the first outer circumferential receiving member 33 whose overall length is set to 1M is placed close to the left inner corner portion of the staircase chamber 2, the right end portion will reach the rear pillar 3c of the staircase chamber 2. When screwing and fixing the first outer circumferential receiving member 33 of the upper circumferential portion 1c, press the left end face (the left end face of the lower connecting portion 33a) against the left side face of the staircase chamber 2, and further place the lower end face of the downward protruding portion 33b on the upper face of the left end portion of the lower circumferential portion 1b. At this time, the upper faces of the lower side and the upper side are horizontal. When it is in such a state, screw and fix both end portions of the first outer circumferential receiving member 33 to the side face on the back side of the staircase chamber 2.

[0089] Subsequently, as shown in FIG. 5 and the like, screw and fix the second outer circumferential receiving member 34 located in the upper circumferential portion 1c of the staircase 1 against the left side face of the staircase chamber 2 exactly. And when the back side end portion of the second outer circumferential receiving member 34 whose overall length is set to 1M is arranged close to the inner corner portion on the left side of the staircase chamber 2, the front side end portion will reach the column 3c on the left side of the staircase chamber 2. When screwing and fixing the second outer circumferential receiving member 34 of the upper circumferential portion 1c, press the back side end face (the back side end face of the upper connecting portion 34a) against the side face on the back side of the staircase chamber 2, and further place the front side end portion on the upper face of the sixth jig bar 16. At this time, the upper faces of the lower side and the upper side are horizontal. Also, the front side end portion protrudes to the front side of the sixth jig bar 16. When it is in such a state, screw and fix both end portions of the second outer circumferential receiving member 34 to the side face on the left side of the staircase chamber 2.

[0090] Next, as shown in FIG. 6 and the like, attach a pair of lower floor side girders 41 to the side face of the handrail wall 6 and the side face of the staircase chamber 2. The pair of lower floor side girders 41 have the same shape, are arranged facing each other, and are respectively screwed and fixed. Vertical surfaces 41a necessary for accurately arranging the pair of lower floor side girders 41 are formed at the upper end portions of the pair of lower floor side girders 41.

[0091] First, as shown in FIG. 6 and the like, press the lower floor side girder 41 on the left side (the handrail wall 6 side) against the right side face of the handrail wall 6 exactly and screw and fix it. At this time, taking the surface of the second side plate portion 31b of the first inner circumferential receiving member 31 provided at the back side end of the handrail wall 6 as a reference surface (datum surface), align the vertical surface 41a of the lower floor side girder 41 with that surface so as to be flush. That is, arrange the vertical surface 41a of the lower floor side girder 41 so that it is not located on the back side or the front side of the surface (back side) of the second side plate portion 31b of the first inner circumferential receiving member 31, and arrange the lower floor side girder 41 so that no step is formed between the vertical surface 41a of the lower floor side girder 41 and the second side plate portion 31b of the first inner circumferential receiving member 31. Then, when the lower floor side girder 41 is fixed to the right side surface of the handrail wall 6 at the position thus aligned, the lower floor side girder 41 will be arranged at the designed position.

[0092] Subsequently, as shown in FIG. 6 and the like, the lower floor side girder 41 on the right side (opposite side of the handrail wall 6) is closely applied to the right side surface of the staircase room 2 and fixed with screws. At this time, taking the front side surface at the upper end of the second jig bar 12 as a reference surface (datum surface), bring the vertical surface 41a of the lower floor side girder 41 into close contact with that surface. Also, align by bringing the upper end surface of this lower floor side girder 41 into close contact with the lower end surface of the downward protruding portion 33b of the first outer circumferential receiving member 33 of the lower circumferential portion 1b. Then, when the lower floor side girder 41 is fixed to the right side surface of the staircase room 2 at the position thus aligned, the lower floor side girder 41 will be arranged at the designed position.

[0093] Next, as shown in FIGS. 7 to 11 and the like, a plurality of circumferential step plates 51, 52, 53 and the decorative kick-in plate 54 in the lower circumferential portion 1b are attached. In the lower circumferential portion 1b, as described above, construction is carried out starting from the lower first circumferential step plate 51, then the middle second circumferential step plate 52 is constructed, and then the upper third circumferential step plate 53 is constructed.

[0094] First, as shown in FIG. 7, a decorative kick-in plate 54 corresponding to the first circumferential step plate 51 is disposed at a position corresponding to below the step nose portion of the first circumferential step plate 51, and the first circumferential step plate 51 is disposed so as to span between the first side plate portion 31a of the first inner circumferential receiving member 31 and the lower side of the first outer circumferential receiving member 33. At this time, the upper end portion of the decorative kick-in plate 54 is in a state of being inserted into the insertion groove 51a formed on the lower surface of the step nose portion of the first circumferential step plate 51. Then, after the upper end portion of the decorative kick-in plate 54 inserted into the insertion groove 51a is placed in close contact with the side surface of the step nose tip of the insertion groove 51a, a kick-in fixing bar 55 is fixed to the lower surface of the first circumferential step plate 51 with screws.

[0095] Subsequently, as shown in FIG. 8, a decorative kick-in plate 54 corresponding to the second circumferential step plate 52 is disposed at a position corresponding to below the step nose portion of the second circumferential step plate 52. At this time, the lower end portion of the decorative kick-in plate 54 has a positional relationship in which it is sandwiched with a gap between the kick-in side end portion of the first circumferential step plate 51 and the connecting side of the first outer circumferential receiving member 33. That is, the lower end portion of the decorative kick-in plate 54 is in a state of being located between the kick-in side end portion of the first circumferential step plate 51 and the connecting side of the first outer circumferential receiving member 33. Moreover, there is a gap with respect to at least one of the kick-in side end portion of the first circumferential step plate 51 and the connecting side of the first outer circumferential receiving member 33. Thereby, for example, even when there are variations in the construction accuracy of the building frame, the variations in the construction accuracy can be absorbed by utilizing the gap. Then, in a subsequent process, the spacer 21 is brought into close contact with the back surface of the outer peripheral side end portion of the decorative kick-in plate 54, and the spacer 21 is fixed to the side surface of the staircase room 2, so that the positional relationship between the decorative kick-in plate 54 inclined according to the variation of the frame and the first circumferential step plate 51 is fixed as it is, and the lower circumferential portion 1b can be arranged at the designed position. And after the decorative kick-in plate 54 on the middle stage side is arranged in this way, a step plate fixing bar 31c fixed to the first side plate portion 31a of the first inner circumferential receiving member 31 on which the lower first circumferential step plate 51 is placed and a step plate fixing bar 33c fixed to the lower side of the first outer circumferential receiving member 33 are fixed to the lower surface of the first circumferential step plate 51 with screws.

[0096] Subsequently, as shown in FIG. 9, the second circumferential step plate 52 is disposed so as to span between the upper end surface of the lower step of the second side plate portion 31b of the first inner circumferential receiving member 31 and the upper side of the first outer circumferential receiving member 33 and the lower side of the second outer circumferential receiving member 34. At this time, the upper end portion of the decorative kick-in plate 54 is in a state of being inserted into the insertion groove 52a formed in the lower surface of the step nose portion of the second circumferential step plate 52. Then, after arranging the upper end portion of the decorative kick-in plate 54 inserted into the insertion groove 52a to fit exactly against the side surface of the step nose tip of the insertion groove 52a, the kick-in fixing bar 55 is fixed to the lower surface of the second circumferential step plate 52 with screws.

[0097] Subsequently, as shown in FIG. 10, the step plate fixing bar 31c fixed to the second side plate portion 31b of the first inner circumferential receiving member 31 on which the middle second circumferential step plate 52 is placed, and the step plate fixing bar 33c fixed to the upper side of the first outer circumferential receiving member 33 and the lower side of the second outer circumferential receiving member 34 are fixed to the lower surface of the second circumferential step plate 52 with screws. Furthermore, the lower end portion of the decorative kick-in plate 54 corresponding to the second circumferential step plate 52 is fixed to the kick-in side end surface of the first circumferential step plate 51 with screws.

[0098] Subsequently, as shown in FIG. 11, the decorative kick-in plate 54 corresponding to the third circumferential step plate 53 is disposed at a position corresponding to the lower part of the step nose portion of the third circumferential step plate 53. At this time, the lower end portion of the decorative kick-in plate 54 has a positional relationship of being sandwiched between the kick-in side end portion of the second circumferential step plate 52 and the connecting side of the second outer circumferential receiving member 34. Furthermore, the third circumferential step plate 53 is disposed so as to span between the upper end surface of the higher step of the second side plate portion 31b of the first inner circumferential receiving member 31 and the upper side of the second outer circumferential receiving member 34. At this time, the upper end portion of the decorative kick-in plate 54 is in a state of being inserted into the insertion groove 53a formed in the lower surface of the step nose portion of the third circumferential step plate 53. Then, after arranging the upper end portion of the decorative kick-in plate 54 inserted into the insertion groove 53a to fit exactly against the side surface of the step nose tip of the insertion groove 53a, the kick-in fixing bar 55 is fixed to the lower surface of the third circumferential step plate 53 with screws. Also, the lower end of the decorative kick-in plate 54 corresponding to the third circumferential step plate 53 is screwed to the kick-in side end face of the second circumferential step plate 52. Furthermore, the decorative kick-in plate 54 corresponding to the first circumferential step plate 51 of the upper circumferential part 1c is arranged at a position corresponding to below the step nose part of the first circumferential step plate 51 in the upper circumferential part 1c. At this time, the lower end of the decorative kick-in plate 54 is in a positional relationship sandwiched between the kick-in side end of the third circumferential step plate 53 in the lower circumferential part 1b, the first side plate part 32a of the second inner circumferential receiving member 32, and the downward protruding part 33b of the first outer circumferential receiving member 33 in the upper circumferential part 1c.

[0099] Next, as shown in FIG. 12, the rectangular step plates 61 and the decorative kick-in plates 62 from the second step from the bottom in the lower floor straight part 1a are attached. In the lower floor straight part 1a, as described above, the construction is carried out in order from the top except for the lowermost rectangular step plate 61.

[0100] First, the decorative kick-in plate 62 corresponding to the rectangular step plate 61 at the fourth step from the bottom is arranged at a position corresponding to below the step nose part of the rectangular step plate 61 at the fourth step from the bottom. Subsequently, the rectangular step plate 61 at the fourth step from the bottom is provided by bridging between the steps of the pair of lower floor side girders 41. At this time, the upper end of the decorative kick-in plate 62 is in a state of being inserted into the insertion groove 61a formed on the lower surface of the step nose part of the rectangular step plate 61 at the fourth step from the bottom. Then, after arranging the upper end of the decorative kick-in plate 62 inserted into the insertion groove 61a to fit exactly against the step nose tip side surface of the insertion groove 61a, the kick-in fixing bar 63 is screwed to the lower surface of the rectangular step plate 61 at the fourth step from the bottom.

[0101] Subsequently, the step plate fixing bar 41b fixed to the steps of the pair of lower floor side girders 41 is screwed to the lower surface of the rectangular step plate 61 at the fourth step from the bottom. At this time, the lower end of the decorative kick-in plate 54 provided below the step nose part of the first circumferential step plate 51 in the lower circumferential part 1b is in a state of being sandwiched between the kick-in side end of the rectangular step plate 61 at the fourth step from the bottom, the first side plate part 31a of the first inner circumferential receiving member 31, and the downward protruding part 33b of the first outer circumferential receiving member 33. Thereafter, the lower end of the decorative kick-in plate 54 corresponding to the first circumferential step plate 51 in the lower circumferential portion 1b is screwed to the kicking end face of the rectangular step plate 61 at the fourth step from the bottom.

[0102] Subsequently, the decorative kick-in plate 62 corresponding to the rectangular step plate 61 at the third step from the bottom is arranged at a position corresponding to the lower part of the step nose portion of the rectangular step plate 61 at the fourth step from the bottom. Then, the rectangular step plate 61 at the third step from the bottom is provided so as to be bridged between the stepped portions of the pair of lower floor side girders 41. Also, after arranging the upper end of the decorative kick-in plate 62 inserted into the insertion groove 61a of the rectangular step plate 61 at the third step from the bottom to fit exactly against the side face of the step nose tip of the insertion groove 61a, the kicking fixing bar 63 is screwed to the lower face of the rectangular step plate 61 at the third step from the bottom.

[0103] Subsequently, the step plate fixing bar 41b fixed to the stepped portions of the pair of lower floor side girders 41 is screwed to the lower face of the rectangular step plate 61 at the third step from the bottom. At this time, the lower end of the decorative kick-in plate 62 provided below the step nose portion of the rectangular step plate 61 at the fourth step from the bottom is in a state of being sandwiched between the kicking side end of the rectangular step plate 61 at the third step from the bottom and the second face of the stepped portions of the pair of lower floor side girders 41. Thereafter, the lower end of the decorative kick-in plate 62 provided below the step nose portion of the rectangular step plate 61 at the fourth step from the bottom is screwed to the kicking end face of the rectangular step plate 61 at the third step from the bottom.

[0104] The method of attaching the rectangular step plate 61 and the decorative kick-in plate 62 at the second step from the bottom is the same as the method of attaching the rectangular step plate 61 and the decorative kick-in plate 62 at the third step from the bottom. When the construction reaches this point, the staircase 1 can move back and forth between the lower floor and the lower circumferential portion 1b. Note that the attachment of the lowermost rectangular step plate 61 is a subsequent process.

[0105] Next, as shown in FIG. 13, a plurality of surrounding step plates 51, 52, 53 and the decorative kick-in plate 54 in the upper surrounding portion 1c are attached. In the upper surrounding portion 1c as well, similar to the case of the lower surrounding portion 1b, construction is carried out starting from the lowermost first surrounding step plate 51, then the construction of the middle second surrounding step plate 52 is carried out, and then the construction of the uppermost third surrounding step plate 53 is carried out. Note that on the lowermost first surrounding step plate 51, the decorative kick-in plate 54 that was previously set at the kick-in side end of the uppermost third surrounding step plate 53 in the lower surrounding portion 1b is attached by screwing the kick-in fixing bar 55. Also, in a later process, at the kick-in side end face of the uppermost third surrounding step plate 53, the lower end portion of the decorative kick-in plate 62 corresponding to the lowermost rectangular step plate 61 among the rectangular step plates 61 provided in the upper floor straight portion 1d is screwed. That is, after the kick-in fixing bar 63 is screwed to the lower surface of the lowermost rectangular step plate 61 in the upper floor straight portion 1d and the positional relationship between the rectangular step plate 61 and the decorative kick-in plate 62 is determined, the lower end portion of the decorative kick-in plate 62 is screwed to the kick-in side end face of the uppermost third surrounding step plate 53. This makes it less likely for floor noise (such as creaking) to occur.

[0106] Next, as shown in FIG. 14, the backing blocks 21 are placed in contact with the back surfaces of the outer peripheral side ends of the respective decorative kick-in plates 54 in the lower surrounding portion 1b and the upper surrounding portion 1c, and these backing blocks 21 are screwed to the side surface of the staircase room 2. As a result, each decorative kick-in plate 54 is less likely to bend in the direction of the back side of the decorative kick-in plate 54, so it is less likely for a gap to occur between each decorative kick-in plate 54 and the respective step plates 51, 52, 53, 61 in contact therewith, and thus it is less likely for floor noise (such as creaking) to occur. Also, if the backing blocks 21 were not provided, when a pushing force is generated on the surface of each decorative kick-in plate 54, it would bend and become a rattling state, and a gap would occur between it and the later-attached edge board 96. Therefore, by providing the backing blocks 21 in this way, the rigidity of each decorative kick-in plate 54 can be ensured, so even when a pushing force is generated on the surface of each decorative kick-in plate 54, it is less likely for a gap to occur with the edge board 96.

[0107] In addition, when the backing block 21 is brought into contact with the back surface of the outer peripheral side end of each decorative kicking-in plate 54, the backing block 21 may be strongly pushed from the back side to the front side of the decorative kicking-in plate 54 and then fixed to the side surface of the staircase chamber 2. Thereby, the outer peripheral side end of the decorative kicking-in plate 54 can be pushed in the direction of the stepped nose tip side surface of the insertion grooves 51a, 52a, 53a and the direction of the kicking-in side ends of the respective step plates 51, 52, 53, 61 located in the lower stage, so that a gap is less likely to occur between each decorative kicking-in plate 54 and each step plate 51, 52, 53, 61 in contact therewith.

[0108] Next, as shown in FIGS. 15 to 18, the upper straight portion 1d of the staircase 1 is constructed. For the construction of the upper straight portion 1d, first, the uppermost frame receiving timber 72 is attached, then, a pair of upper floor side girders 42 are attached, and after that, a plurality of rectangular step plates 61 and a plurality of decorative kicking-in plates 62 are attached, and then the uppermost frame 71 is attached.

[0109] As shown in FIG. 15, the uppermost frame receiving timber 72 is arranged with the notch portion 72a facing the back side and then fixed to the back surface of the upper floor beam 8 with screws. At this time, the upper end surface of the uppermost frame receiving timber 72 and the upper surface of the upper floor 9 are flush. Further, the uppermost frame receiving timber 72 is arranged such that there is a gap between the right end portion of both ends in the length direction and the left side surface of the handrail wall 6, and there is a gap between the left end portion and the left side surface of the staircase chamber 2. The interval dimensions of the gaps on both sides in such an uppermost frame receiving timber 72 are set to be equal. And the upper end portions of a pair of upper floor side girders 42 are arranged in these gaps.

[0110] Subsequently, as shown in FIG. 16, a pair of upper floor side girders 42 are attached. For the right upper floor side girder 42 of the pair of upper floor side girders 42, the lower end portion is placed on the upper end surface of the second side plate portion 32b of the second inner circumferential receiving member 32. Also, for the left upper floor side girder 42, the lower end portion is placed on the upper surface of the front side end portion on the upper side of the second outer circumferential receiving member 34.

[0111] Further, a decorative kick-in plate 62 corresponding to the lowermost rectangular step plate 61 among the plurality of rectangular step plates 61 in the upper straight portion 1d is temporarily placed on the kicking side end surface of the upper third circumferential step plate 53 in the upper circumferential portion 1c. Therefore, when arranging the pair of upper floor side girders 42, the vertical surfaces at the lower end portions of the pair of upper floor side girders 42 are brought into contact with the back side surface of the decorative kick-in plate 62 and sandwiched between the kicking side end surface of the upper third circumferential step plate 53 in the upper circumferential portion 1c. More specifically, the vertical surfaces at the lower end portions of the pair of upper floor side girders 42 are made to exactly contact the back side surface of the temporarily placed decorative kick-in plate 62, and further, the temporarily placed decorative kick-in plate 62 is brought into close contact with the kicking side end surface of the upper third circumferential step plate 53 in the upper circumferential portion 1c without any gap.

[0112] Furthermore, when arranging the pair of upper floor side girders 42, the upper end portions of the pair of upper floor side girders 42 are arranged in the gaps on both sides in the uppermost frame receiving wood 72, and are arranged so that the upper end surfaces of the upward protruding portions 42a are in a horizontal state. At this time, the height position of the upper end surface of the upward protruding portion 42a is equal to the height position of the upward facing surface in the notch portion 72a of the uppermost frame receiving wood 72.

[0113] That is, the pair of upper floor side girders 42 are aligned with the height position of the upward facing surface in the notch portion 72a of the uppermost frame receiving wood 72 at the upper end portions, and the lower end portions are horizontally aligned with the kicking side end surface of the upper third circumferential step plate 53 in the upper circumferential portion 1c. Therefore, even if there are variations in the body, the pair of upper floor side girders 42 can be arranged at the designed positions in the upper straight portion 1d of the staircase 1. As a result, compared with the case of trying to absorb the variations in the body only by designing the shape and dimensions of the pair of upper floor side girders 42, it becomes easier to arrange the pair of upper floor side girders 42 at the designed positions. Once the pair of upper floor side girders 42 are arranged in the above state, the right upper floor side girder 42 is fixed to the left side surface of the handrail wall 6 with screws. More specifically, it is fixed to the central column 3a, the front column 3, and the intermediate column 4 located inside the handrail wall 6 with screws through the fireproof coating material 5. Also, the upper-story side girder 42 on the left side is screwed to the left side surface of the staircase chamber 2. More specifically, it is screwed to the left pillar 3d, the front pillar 3, and the intermediate pillar 4 located inside the left side surface in the staircase chamber 2 via the fireproof coating material 5.

[0114] Next, as shown in FIG. 17, a plurality of rectangular tread plates 61 and decorative kick-in plates 62 in the upper-story straight portion 1d are attached. In the upper-story straight portion 1d, as described above, the construction is carried out in order from the bottom.

[0115] On the kick-in side end face of the upper third turn tread plate 53 in the upper side turning portion 1c, the decorative kick-in plate 62 is screwed in a later process. Therefore, when attaching the first rectangular tread plate 61 from the bottom, the rectangular tread plate 61 is arranged such that the upper end portion of the decorative kick-in plate 62 is inserted into the insertion groove 61a on the lower surface at the step nose portion of the rectangular tread plate 61. At this time, the first rectangular tread plate 61 from the bottom is placed on and bridged over the horizontal first surface at the lowermost step portion of the pair of upper-story side girders 42.

[0116] Subsequently, the lower end portion of the decorative kick-in plate 62 corresponding to the second rectangular tread plate 61 from the bottom is arranged so as to be sandwiched between the kick-in side end portion of the first rectangular tread plate 61 from the bottom and the vertical second surface of the second step portion of the pair of upper-story side girders 42.

[0117] Subsequently, with the upper end portion of the decorative kick-in plate 62 inserted into the insertion groove 61a of the first rectangular tread plate 61 from the bottom, the kick-in fixing bar 63 fixed in advance to the decorative kick-in plate 62 is screwed to the lower surface of the first rectangular tread plate 61 from the bottom.

[0118] Subsequently, the tread plate fixing bar 42b attached to the upper end portion of the step portion on which the first rectangular tread plate 61 from the bottom is placed among the pair of upper-story side girders 42 is screwed to the lower surface of the first rectangular tread plate 61 from the bottom. Thereafter, the lower end portion of the decorative kick-in plate 62 corresponding to the second rectangular tread plate 61 from the bottom is screwed to the kick-in side end of the first rectangular tread plate 61 from the bottom.

[0119] Then, the construction of the second rectangular step plate 61 from the bottom, the third rectangular step plate 61 from the bottom, and the fourth rectangular step plate 61 from the bottom shall be carried out in the same manner as the construction of the first rectangular step plate 61 from the bottom described above.

[0120] When the fourth rectangular step plate 61 from the bottom is placed and spanned on the horizontal first surface of the uppermost step portion of the pair of upper floor side girders 42, and the step plate fixing bar 42b is screwed to the lower surface of the fourth rectangular step plate 61 from the bottom, as shown in Fig. 18, the uppermost frame 71 and the decorative kicking-in plate 62 are attached.

[0121] The uppermost frame 71 and the uppermost decorative kicking-in plate 62 are integrally provided as described above. That is, as shown in Fig. 18(b), the upper end portion of the decorative kicking-in plate 62 is inserted into the insertion groove 71a of the uppermost frame 71 and screwed. Therefore, when attaching the uppermost frame 71 and the decorative kicking-in plate 62, among the uppermost frame 71 and the decorative kicking-in plate 62 formed in this way, the lower end portion of the decorative kicking-in plate 62 is inserted between the kicking-in side end portion of the fourth rectangular step plate 61 from the bottom and the upward protruding portion 42a of the pair of upper floor side girders 42. Also, at this time, place the uppermost frame 71 on the upward-facing surface of the notch portion 72a of the uppermost frame receiving member 72. Then, screw-fix the uppermost frame 71 from the notch portion 71b toward the upward-facing surface of the notch portion 72a of the uppermost frame receiving member 72. Furthermore, screw-fix the lower end portion of the decorative kicking-in plate 62 to the kicking-in side end surface of the fourth rectangular step plate 61 from the bottom.

[0122] Next, as shown in Fig. 19, attach the lowermost rectangular step plate 61 and the lowermost decorative kicking-in plate 83 in the lower floor straight portion 1a.

[0123] First, as shown in Fig. 19(b), screw-fix the kicking-in fixing bar 63 to the lower surface of the lowermost rectangular step plate 61 in advance. Then, arrange the floor kicking-in fixing bar 81 between the pair of lower floor side girders 41 and screw-fix it to the rough floor surface 7.

[0124] Subsequently, the lowermost rectangular step board 61 to which the kicking fixing bar 63 is fixed is placed and bridged on the horizontal first surface of the lowermost step portion of the pair of lower floor side girders 41, and the step board fixing bar 41b of the pair of lower floor side girders 41 is screwed to the lower surface of the lowermost rectangular step board 61. At this time, the floor kicking fixing bar 81, the kicking fixing bar 63 fixed to the lower surface of the lowermost rectangular step board 61, and the end faces at the lower ends of the pair of lower floor side girders 41 are in a state of being formed in a rectangular frame shape.

[0125] Subsequently, the lower end of the decorative kicking board 62 whose upper end is inserted into the insertion groove 61a of the second rectangular step board 61 from the bottom in the lower floor straight portion 1a is screwed to the kicking side end face of the lowermost rectangular step board 61.

[0126] Thereafter, the base plywood 82 is screwed to the portion formed in a rectangular frame shape as described above. And, the decorative kicking board 83 for the lowermost step is adhered and attached to the surface of the base plywood 82 thus screwed. Thereby, the attachment of the lowermost rectangular step board 61 and the decorative kicking board 83 for the lowermost step is completed.

[0127] Next, as shown in FIG. 20, various staircase edge members 91 to 98 included in the staircase edge member set 90 are provided at the mating portion between the staircase 1 and the wall surface of the staircase room 2. Note that before attaching the staircase edge members 91 to 98, a finishing material such as wall cloth may be attached to the side surface of the staircase room 2 including the side surface of the handrail wall 6.

[0128] The construction of the staircase 1 is performed as described above. Note that if the procedure is changed among the construction methods consisting of the above-described steps and the construction efficiency is not impaired or the strength of the staircase 1 is not impaired, it may be appropriately changed in consideration of the site conditions and the like.

[0129] 〔Regarding effects〕 According to the present embodiment, the following excellent effects are obtained. That is, the construction method of the staircase 1 in this embodiment is to construct the staircase 1 according to the module M inside the staircase room 2 formed by a through-hole from the lower floor to the upper floor in a building designed by arranging walls according to the module M which is the design standard. The staircase room 2 has a rough floor surface 7 as the floor of the lower floor and wall surfaces of walls orthogonal to the rough floor surface 7 (side surfaces of the staircase room 2, side surfaces of the handrail wall 6). The staircase 1 is constructed by assembling a plurality of types of staircase components (fixture bar set 10, backing wood set 20, surrounding receiving member set 30, side girder set 40, surrounding tread board set 50, tread board set 60, topmost frame set 70, lowermost kicking board set 80, staircase ledger set 90) from the rough floor surface 7. The plurality of types of staircase components include one staircase component (backing wood 21, first fixture bar 11, second fixture bar 12, first inner surrounding receiving member 31, etc.) and another staircase component (second fixture bar 12, lower floor side girder 41, etc.) that are continuously provided with each other. It has a step of attaching one staircase component to a predetermined position in accordance with the module M and a step of attaching another staircase component to a position continuous with the one staircase component. One side surface of the one staircase component attached to the predetermined position serves as a reference surface for positioning the other staircase component in accordance with the module M. Since the other staircase component is arranged along the reference surface when it is attached, by attaching one staircase component to a predetermined position in accordance with the module M and arranging the other staircase component along the reference surface which is one side surface of this one staircase component, it becomes possible to attach the other staircase component to a predetermined position in accordance with the module M. As a result, the positioning of each part of the staircase 1 can be easily performed without performing layout work, and the constructability of the staircase 1 can be improved.

[0130] In addition, the plug 21 included in the plurality of types of staircase components is set to a predetermined width dimension (93 mm). After temporarily fixing one of the plurality of plugs 21 (see FIGS. 3 and 6) at a position along the reference line L indicating the position of the module M in the design, along one side surface (the end surface on the back side) of this one plug 21, arranging a second jig bar 12, which is one of the plurality of rod-shaped jigs, and fixing it to the wall surface; and after removing the temporarily fixed one plug 21, arranging a right lower floor side girder 41, which is one of the plurality of side girders, along one side surface (the side surface on the front side) of the second jig bar 12 and fixing it to the wall surface. Therefore, the plug 21 and the second jig bar 12 are attached at predetermined positions according to the module, and by simply arranging the right lower floor side girder 41 along the reference surface, which is one side surface (the side surface on the front side) of the second jig bar 12, the right lower floor side girder 41 can be attached at a predetermined position according to the module M. As a result, the positioning of the lower floor side girder 41 of the staircase 1 can be easily performed without performing ink marking work, and the constructability of the staircase 1 can be improved.

[0131] Also, after removing the temporarily fixed one plug 21, the one plug 21 is arranged in contact with the back side surface of the end portion of the decorative kick-in plate 54, which is a kick-in plate, and fixed to the wall surface. Therefore, the decorative kick-in plate 54 is less likely to bend in the direction on the back side of the decorative kick-in plate 54. As a result, it is less likely that a gap will occur between each step plate 51, 52, 53, 61 or the fascia 96 in contact with the decorative kick-in plate 54. Thus, even if there are variations in the construction accuracy of the building structure, for example, the variations in the construction accuracy can be absorbed. Furthermore, floor noise (such as creaking) is less likely to occur. Moreover, since the plug 21 used for attaching the lower floor side girder 41 can be diverted for attaching other parts, it is possible to prevent waste of materials. Therefore, it can contribute to the realization of a decarbonized society by promoting carbon neutrality and the achievement of the SDGs, which have been demanded in recent years.

[0132] Further, a step of arranging a first jig bar 11, which is another one of the plurality of rod-shaped jigs, along one side surface at the end located at the center of the staircase room 2 in the handrail wall 6 and fixing it to the handrail wall 6; a step of placing a first inner circumferential receiving member 31, which is one of the plurality of receiving members, on the upper end surface of the first jig bar 11 and fixing it to the handrail wall 6; and a step of arranging a left lower floor side girder 41, which is another one of the plurality of side girders, along one side surface (the side surface on the back side) of the first inner circumferential receiving member 31 and fixing it to the handrail wall 6. Therefore, by attaching the first inner circumferential receiving member 31 at a predetermined position according to the module and arranging the left lower floor side girder 41 along the reference surface, which is one side surface (the side surface on the back side) of the first inner circumferential receiving member 31, it is possible to attach the left lower floor side girder 41 at a predetermined position according to the module M. As a result, the positioning of the lower floor side girder 41 of the staircase 1 can be easily performed without ink marking work, and the constructability of the staircase 1 can be improved.

[0133] 〔Modification Example〕 Note that the embodiments to which the present invention is applicable are not limited to the above-described embodiments and can be appropriately changed without departing from the gist of the present invention. Hereinafter, modification examples will be described. In each of the following modification examples, elements common to the above-described embodiments are denoted by common reference numerals, and the description will be omitted or simplified.

[0134] In the above-described embodiment, the positioning work of the second jig bar 12 was performed using the template 21. However, in this modification example, as shown in FIG. 1, the positioning work of the second jig bar 12A is performed without using the template 21.

[0135] That is, in this modification example, the front side surface of the side surfaces of the second jig bar 12A is arranged to align with the center line (reference line L) of the right column 3b and fixed to the right column 3b with screws. When the position of the second jig bar 12A is changed in this way, although the position of the right lower floor side beam 41A in the lower straight part 1a is the same as that of the right lower floor side beam 41 in the above embodiment, the shape is different. That is, the right lower floor side beam 41A in this modification has the same arrangement position at the lower end, but as shown in FIG. 6(c), the back side end of the upper end is cut at the position of the reference line L and the vertical surface 41a is formed to be vertically long. Then, the vertical surface 41a formed at the upper end of the right lower floor side beam 41A is brought into close contact with the front side surface at the upper end of the second jig bar 12A arranged and fixed in this way. Further, the upper end surface of the second jig bar 12A and the upper end surface of the right lower floor side beam 41A are aligned.

[0136] Also, if only the position of the second jig bar 12A is changed, a deviation will occur between the pair of lower floor side beams 41, so the position of the first jig bar 11 is also changed. That is, in this modification, the first jig bar 11A is arranged on the right side surface of the central column 3a, and the front side surface among the side surfaces of this first jig bar 11A is arranged in alignment with the center line (reference line L) of the central column 3a and fixed to the central column 3a with screws. When the position of the first jig bar 11A is changed in this way, although the position of the left lower floor side beam 41A in the lower straight part 1a is the same as that of the left lower floor side beam 41 in the above embodiment, the shape is different. That is, the left lower floor side beam 41A in this modification has the same arrangement position at the lower end, but the back side end of the upper end is cut at the position of the reference line L and the vertical surface 41a is formed to be vertically long (not shown). In other words, it has a shape symmetrical to the right lower floor side beam 41A. Then, the vertical surface 41a formed at the upper end of the left lower floor side beam 41A is brought into close contact with the front side surface at the upper end of the first jig bar 11A arranged and fixed in this way. Further, the upper end surface of the first jig bar 11A and the upper end surface of the left lower floor side beam 41A are aligned.

[0137] Further, even if the positions of the first jig bar 11A and the second jig bar 12A are changed, it is not necessary to change the configuration and arrangement in the lower circumferential portion 1b and the upper circumferential portion 1c. That is, for example, as shown in FIG. 6, even when the second jig bar 12A is arranged at a position where its front side surface is aligned with the reference line L, the lower protruding portion 33b of the first outer circumferential receiving member 33 can be placed on the upper end surface of the second jig bar 12A. Furthermore, even when the first jig bar 11A is arranged at a position where its front side surface is aligned with the reference line L, the first side plate portion 31a of the first inner circumferential receiving member 31 can be placed on the upper end surface of the first jig bar 11. Also, even if the positions of the first jig bar 11A and the second jig bar 12A are changed, it is not necessary to change the configuration and arrangement in the upper floor straight portion 1d.

[0138] When the construction method of the staircase 1 in this modified example is adopted, it becomes unnecessary to perform the positioning operation of the second jig bar 12A using the spacer 21, and the spacer 21 is only used to back up each decorative kicking plate 54 in the lower circumferential portion 1b and the upper circumferential portion 1c from the back side. Also, in this modified example, all the jig bars 11A, 12A, 14, 16 except the jig bars (the third jig bar 13 and the fifth jig bar 15) provided at the corner portion of the staircase room 2 are arranged with the front side surface when viewed from the upward direction of the staircase 1 among the side surfaces of the jig bars 11A, 12A, 14, 16 aligned with the position of the reference line L, and the construction of the staircase 1 can be performed based on the unified design.

[0139] According to this modification example, one stepped component, which is the first jig bar 11A or the second jig bar 12A, is attached to a predetermined position conforming to the module M. Along the reference surface, which is one side surface of this one stepped component, by simply arranging another stepped component, which is the lower floor side girder 41, it becomes possible to attach the said other stepped component to a predetermined position conforming to the module M. Thereby, positioning of each part of the staircase 1 can be easily performed without performing an inking operation, and the constructability of the staircase 1 can be improved. Also, the space under the staircase room 2 can be efficiently utilized, the number of processes when constructing the staircase 1 is reduced, and the construction procedures are also unified, thus greatly contributing to the improvement of the constructability of the staircase 1.

Explanation of Signs

[0140] 1 Staircase, 1a Lower floor straight part, 1b Lower side turning part, 1c Upper side turning part, 1d Upper floor straight part 2 Staircase room, 3 Column, 3a Central column, 3b Column on the right side with respect to the central column, 3c Column on the back side with respect to the central column, 3d Column on the left side with respect to the central column, 4 Intermediate column, 5 Fireproof coating material, 6 Handrail wall, 7 Rough floor surface, 8 Upper floor beam, 9 Upper floor, 9a Floor finishing material 10 Jig bar set, 11 First jig bar, 12 Second jig bar, 13 Third jig bar, 14 Fourth jig bar, 15 Fifth jig bar, 16 Sixth jig bar 20 Packing set, 21 Packing 30 Surrounding receiving member set, 31 First inner surrounding receiving member, 31a First side panel part, 31b Second side panel part, 31c Step plate fixing bar, 32 Second inner surrounding receiving member, 32a First side panel part, 32b Second side panel part, 32c Step plate fixing bar, 33 First outer surrounding receiving member, 33a Lower connecting part, 33b Lower protruding part, 33c Step plate fixing bar, 34 Second outer surrounding receiving member, 34a Upper connecting part, 34c Step plate fixing bar 40 Side girder set, 41 Lower floor side girder, 41a Vertical surface, 41b Step plate fixing bar, 42 Upper floor side girder, 42a Upper protruding part, 42b Step plate fixing bar 50 Surrounding step plate set, 51 First surrounding step plate, 51a Insertion groove, 52 Second surrounding step plate, 52a Insertion groove, 53 Third surrounding step plate, 53a Insertion groove, 54 Decorative kicking-in plate, 55 Kicking-in fixing bar 60-piece plate set, 61 rectangular plate, 61a insertion groove, 62 decorative kicking-in plate, 63 kicking-in fixing bar 70 topmost frame set, 71 topmost frame, 71a insertion groove, 71b notch, 72 topmost frame receiving beam, 72a notch 80 bottommost kicking-in plate set, 81 floor kicking-in fixing bar, 82 base plywood, 83 bottommost decorative kicking-in plate 90 staircase width beam set, 91 width beam, 92 width beam, 93 width beam, 94 width beam, 95 width beam, 96 width beam, 97 width beam, 98 width beam L reference line

Claims

1. In a building designed by arranging walls according to a module serving as a design standard, in a method for constructing a staircase in which the staircase is constructed from a lower floor to an upper floor inside a staircase room formed by a void extending from the lower floor to the upper floor, the staircase room has a floor of the lower floor and a wall surface of the wall orthogonal to the floor of the lower floor, the staircase is constructed by assembling a plurality of types of staircase components from the floor, the plurality of types of staircase components include one staircase component and another staircase component that are provided continuously with each other, a step of attaching the one staircase component to a predetermined position according to the module, a step of attaching the other staircase component to a position continuous with the one staircase component, and one side surface of the one staircase component attached to the predetermined position is a reference surface that can position the other staircase component according to the module, The method for constructing a staircase is characterized in that the other staircase component is arranged along the reference surface when it is attached.

2. The plurality of types of staircase components include a plurality of treads, a plurality of kick plates each fixed to each of the treads to form a kicking surface, a plurality of receiving members that receive and support the plurality of treads, a plurality of side girders that are arranged continuously with the plurality of receiving members and receive and support the plurality of treads, a plurality of rod-shaped jigs that support the plurality of receiving members, and a plurality of backing blocks each provided on the back side of each of the kick plates to back up each of the kick plates from the back side, and the backing blocks are set to a predetermined width dimension, after temporarily fixing one of the plurality of backing blocks to a position along a reference line indicating the position of the module in design, arranging one of the plurality of rod-shaped jigs along one side surface of this one backing block and fixing it to the wall surface, The method for constructing a staircase according to claim 1, further comprising a step of arranging one of the plurality of side girders along one side surface of the one rod-shaped jig and fixing it to the wall surface after removing the temporarily fixed one backing block.

3. The method for constructing a staircase according to claim 2, characterized in that after removing the temporarily fixed one backing block, the one backing block is arranged in contact with the back side surface of the end portion of the kick plate and fixed to the wall surface.

4. The said landing chamber is arranged at the center of this landing chamber and has a handrail wall set to a height reaching from the lower floor to the upper floor. The said staircase is formed in a state of surrounding the handrail wall and is a type of staircase whose traveling direction changes as it goes from the lower floor to the upper floor. A step of arranging another one of the plurality of rod-shaped jigs along one side surface at the end portion located at the center of the landing chamber of the handrail wall and fixing it to the handrail wall. A step of placing one of the plurality of receiving members on the upper end surface of the other one of the rod-shaped jigs and fixing it to the handrail wall. A step of arranging another one of the plurality of side girders along one side surface of the one receiving member and fixing it to the handrail wall. The construction method of the staircase according to claim 2, characterized by comprising the above steps.

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