Tread support structure for stairway and stairway

Abstract

To provide a tread support structure of spiral stairs and the stairs, capable of reducing cost, while clearing restriction on design of a tread receiving base.SOLUTION: In a support structure for a spiral staircase in which an outer edge of a tread 10 is supported by a tread receiving base 11,12 in the spiral staircase 100 in which a plurality of treads 10 are arranged while changing directions in a staircase room surrounded by an inner column 6 and a plurality of outer columns 1,2,3,4,5, the tread receiving base 11,12 is formed of a single plate having a vertical portion, and an upper horizontal portion and a lower horizontal portion extending in opposite directions from upper and lower ends of the vertical portion, and has a horizontal length substantially equal to an interval D between adjacent outer columns. The horizontal width of the vertical portion is preferably larger than the vertical widths of the upper horizontal portion and the lower horizontal portion, and is preferably equal to or larger than the 150mm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tread support structure for a spiral staircase and to a staircase. [Background technology]

[0002] Conventionally, spiral staircases have been constructed in which the direction of travel gradually changes midway. A spiral staircase is a staircase surrounded by an inner column and multiple outer columns, with multiple treads arranged in a way that changes direction.

[0003] The multiple treads in a spiral staircase have their inner edges supported by an inner column (center column) in the center of the staircase, and their outer edges supported by tread supports arranged along the outer columns on the outside of the staircase.

[0004] Regarding such a step support, Patent Document 1 describes a support beam made by overlapping and joining an L-shaped first component and an L-shaped second component, and the upper part of the support beam supports the outer edge of the step.

[0005] Furthermore, Patent Document 2 describes a side plate having a joining groove formed on the outer edge of the tread, and the outer edge of the tread is joined to the joining groove to support it.

[0006] Furthermore, Patent Document 3 describes a support base whose upper oblique side and top side are formed in a sawtooth shape, and the upper part of the support base supports the outer edge of the tread. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-028977 [Patent Document 2] Japanese Patent Application Publication No. 2020-147946 [Patent Document 3] Japanese Patent Publication No. 2022-116808 Summary of the Invention [Problem to be solved by the invention]

[0008] Since the heavier the footplate support, the higher the transportation costs, it is preferable to reduce the amount of material used to make it lighter. In addition, when manufacturing the footplate support, it is preferable to reduce waste materials to reduce costs and improve environmental friendliness.

[0009] On the other hand, for spiral staircases, the Building Standards Act regulates the uniformity of riser height and tread width, so the riser height of the tread support and the length of the part on which the tread rests cannot be changed because they are determined by the basic structure of the building (size of the stairwell, height of the second floor, number of stair steps, how the space under the stairs is used, etc.).

[0010] Furthermore, in order to position the step support along the outer columns of the spiral staircase, it is necessary to fix it to the outer columns or to the partitions between adjacent outer columns. However, when designing the step support, it is necessary to take into account the load on the step support, which varies depending on the fixing position.

[0011] The present invention solves the above-mentioned conventional problems and provides a tread support structure for a spiral staircase and a staircase that can achieve cost reduction while overcoming the design constraints of the tread support base. [Means for solving the problem]

[0012] In order to solve the above problems, the support structure for a spiral staircase of the present invention is a support structure for a spiral staircase in which multiple treads are arranged in changing directions in a staircase chamber surrounded by an inner column and multiple outer columns, and in which the outer edges of the treads are supported by a tread support base, wherein the tread support base is made up of a single plate having a vertical portion and an upper horizontal portion and a lower horizontal portion extending in opposite directions from the upper and lower ends of the vertical portion, and whose horizontal length is approximately the same as the distance between adjacent outer columns.

[0013] Preferably, the horizontal width of the vertical portion is greater than the vertical widths of the upper horizontal portion and the lower horizontal portion.

[0014] Preferably, the horizontal width of the vertical portion is 150 mm or more.

[0015] The staircase of the present invention also has a support structure for the spiral staircase. [Effects of the Invention]

[0016] The support structure for a spiral staircase of the present invention is a support structure for a spiral staircase in which multiple treads are arranged in changing directions in a staircase chamber surrounded by inner columns and multiple outer columns, and in which the outer edges of the treads are supported by a tread support base.The tread support base has a vertical section and an upper horizontal section and a lower horizontal section that extend in opposite directions from the upper and lower ends of the vertical section, thereby reducing the amount of material used by the space below the upper horizontal section and the space above the lower horizontal section.Furthermore, since it is made of a single plate, it is easy to manufacture without the need to combine multiple parts.Furthermore, since the horizontal length of the tread support base is approximately the same as the distance between adjacent outer columns, the left and right ends can be fixed to the outer columns without waste.

[0017] Furthermore, by making the horizontal width of the vertical section wider than the vertical width of the upper horizontal section and the lower horizontal section, the strength of the tread support can be increased to withstand loads even when the vertical section cannot be fixed to the partition post between adjacent outer columns.

[0018] Furthermore, by making the horizontal width of the vertical part 150 mm or more, even if the vertical part cannot be fixed to the partition post between adjacent outer columns, the strength of the tread support can be increased to withstand the load.

[0019] Furthermore, since the staircase of the present invention has the support structure for the spiral staircase, it is possible to reduce costs while overcoming design constraints on the tread support base.

[0020] Thus, according to the present invention, it is possible to provide a tread support structure for a spiral staircase and a staircase that can achieve cost reduction while overcoming the design constraints of the tread support base. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a fitting diagram showing a spiral staircase according to the first embodiment. [Figure 2] FIG. 2 is a perspective view showing the attached state of the tread support of the spiral staircase according to the first embodiment. [Figure 3] FIG. 1 is a front view showing a tread support base of a spiral staircase according to a first embodiment. [Figure 4] FIG. 10 is a fitting diagram showing a spiral staircase according to a second embodiment. [Figure 5] FIG. 10 is a perspective view showing the attached state of the tread support of the spiral staircase according to the second embodiment. [Figure 6] FIG. 10 is a front view showing a tread support base of a spiral staircase according to a second embodiment. [Figure 7] FIG. 10 is a fitting diagram showing a spiral staircase according to a third embodiment. [Figure 8] FIG. 10 is a perspective view showing the attached state of the tread support of the spiral staircase according to the third embodiment. [Figure 9] FIG. 10 is a front view showing a tread support base of a spiral staircase according to a third embodiment. [Figure 10] FIG. 10 is a fitting diagram showing a spiral staircase according to a fourth embodiment. [Figure 11] FIG. 10 is a perspective view showing the attached state of the tread support of the spiral staircase according to the fourth embodiment. [Figure 12] FIG. 10 is a front view showing a tread support of a spiral staircase according to a fourth embodiment. [Figure 13] FIG. 10 is a fitting diagram showing a spiral staircase according to a fifth embodiment. [Figure 14] FIG. 10 is a perspective view showing the attached state of the tread support of the spiral staircase according to the fifth embodiment. [Figure 15] FIG. 10 is a front view showing a tread support base of a spiral staircase according to a fifth embodiment. [Figure 16]FIG. 10 is an explanatory diagram of a method for arranging a step support on a rectangular plate material. [Figure 17] FIG. 10 is an explanatory diagram of a method for arranging a step support on a rectangular plate material. DETAILED DESCRIPTION OF THE INVENTION

[0022] 1 to 17, a tread support structure for a spiral staircase according to an embodiment of the present invention will be described. The spiral staircase support structure according to this embodiment relates to a spiral staircase in which the direction of travel gradually changes midway up the stairs. A spiral staircase has multiple treads arranged in changing directions in a staircase chamber surrounded by an inner column and multiple outer columns, and the outer edges of the treads are supported by tread support bases.

[0023] (Embodiment 1) Figure 1 is an installation diagram showing a spiral staircase 100 according to the first embodiment, Figure 2 is a perspective view showing the installation state of the tread support of the spiral staircase 100, and Figure 3 is a front view showing the tread support of the spiral staircase 100. The installation diagrams of this application are arranged with front views of the spiral staircase as seen from the inside of the staircase room on the top and left and right sides of the plan view, based on the position of the columns in each view. For convenience of explanation, the tread support and columns are mainly shown, and the plan view is drawn so that the position and shape of the spiral tread can be seen. Also, in the perspective view showing the installation state of the tread support, the top of the inner column 6 is drawn lower than it actually is so that the installation state of the tread support is not hidden for convenience of explanation.

[0024] The spiral staircase 100 is a staircase room surrounded by an inner column 6 and outer columns 1, 2, 3, 4, and 5, and has six treads 10a, 10b, 10c, 10d, 10e, and 10f (hereinafter also referred to as "treads 10") arranged in a counterclockwise direction, changing direction by 180 degrees from the lower floor to the upper floor.

[0025] The distance D between adjacent outer posts (the distance from the center of one post to the center of the other post) is all the same, for example, 910 mm. A stud 7 is provided in the center between adjacent outer posts. In addition, splices 8 for fixing treads 10 are attached to the outer posts 2, 4 at the corners.

[0026] The inner edge of the tread 10 is fixed to and supported by the inner column 6. Meanwhile, the outer edge of the tread 10 is supported by tread supports 11 and 12 arranged in a stepped pattern along the outer columns 1, 2, 3, 4 and 5. The spiral staircase 100 according to the first embodiment is made up of six 180-degree steps, but the first half of the treads 10a, 10b and 10c and the second half of the treads 10d, 10e and 10f are all identical in configuration with three 90-degree steps, so only the first half will be described below.

[0027] The treads 10a, 10b, and 10c are shaped to have three 90-degree steps so as to meet the uniformity of the rise height and tread width regulated by the Building Standards Act.

[0028] A step support 11 is attached between the outer columns 1 and 2. The lower end of the step support 11 is fixed to the outer column 1, and a riser 13 is fixed below that. The upper end of the step support 11 is fixed to a support column 8 attached to the outer column 2. The lower horizontal part of the step support 11 (described later) is fixed to a stud 7 between the outer columns 1 and 2.

[0029] A step support 12 is attached between the outer columns 2 and 3. The lower end of the step support 12 is fixed to a support column 8 attached to the outer column 2. The upper end of the step support 12 is fixed to the outer column 3, and a riser 13 is fixed above it. The vertical part of the step support 12 (described later) is attached to a stud 7 between the outer columns 2 and 3.

[0030] As shown in Figures 1 and 2, the lower horizontal portion of the step support base 11 supports the outer edge of the step 10a, the upper horizontal portion of the step support base 11 and the lower horizontal portion of the step support base 12 support the outer edge of the step 10b, and the upper horizontal portion of the step support base 12 supports the outer edge of the step 10c.

[0031] Next, the step board supports 11 and 12 will be described in detail. Fig. 3(a) is a front view of the step board support 11. Fig. 3(b) is a front view of the step board support 12. The ends of each member are shaped to match the members to be joined.

[0032] The step support 11 is made of a single plate having a vertical portion 11a and an upper horizontal portion 11b and a lower horizontal portion 11c that extend in opposite directions from the upper and lower ends of the vertical portion 11a. The horizontal length L11 of the step support 11 is approximately the same as the distance D between adjacent outer posts shown in Figure 1. Here, being made of a single plate means that it is made by processing the shape from a single piece of wood material such as plywood, without combining multiple components.

[0033] The horizontal width W11a of the vertical portion 11a is preferably wider than the vertical width W11b of the upper horizontal portion 11b and the vertical width W11c of the lower horizontal portion 11c. The horizontal width W11a of the vertical portion 11a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads.

[0034] The step support 12 is composed of a single plate having a vertical portion 12a and an upper horizontal portion 12b and a lower horizontal portion 12c that extend in opposite directions from the upper and lower ends of the vertical portion 12a. The horizontal length L12 of the step support 12 is approximately the same as the distance D between adjacent outer columns shown in Figure 1.

[0035] The horizontal width W12a of the vertical portion 12a is preferably wider than the vertical width W12b of the upper horizontal portion 12b and the vertical width W12c of the lower horizontal portion 12c. The horizontal width W12a of the vertical portion 12a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads.

[0036] Here, the positions at which tread support 11 and tread support 12 are fixed to the studs 7 between the outer columns are different. That is, tread support 11 has its lower horizontal portion 11c fixed to the stud 7, while tread support 12 has its vertical portion 12a fixed to the stud 7. As a result, tread support 11, whose lower horizontal portion 11c is fixed to the stud 7, is less able to withstand the vertical load from the upper tread supported by the upper horizontal portion than tread support 12, whose vertical portion 12a is fixed to the stud 7. For this reason, when the tread support is fixed in a position like tread support 11, it is more effective to increase the horizontal width of the vertical portion.

[0037] Figure 3(c) shows the tread support bases 11, 12 and riser 13 arranged on a single rectangular plate for manufacturing. The horizontal length L10 of the rectangular plate is approximately the same as the distance D between adjacent outer columns shown in Figure 1. The two tread support bases are arranged so that at least two pairs of horizontal sides of each are adjacent, and then two tread support bases are cut out. Specifically, the upper edge of the upper horizontal portion 11b of tread support base 11 is adjacent to the lower edge of the upper horizontal portion 12b of tread support base 12, and the upper edge of the lower horizontal portion 11c of tread support base 11 is adjacent to the lower edge of the lower horizontal portion 12c of tread support base 12. Because the rise height of the stairs is uniform, if the vertical widths of the horizontal portions are the same, the adjacent sides of these adjacent horizontal portions will be the same distance apart.

[0038] As mentioned above, of the tread support bases 11 and 12, the vertical portion 11a of the tread support base 11 is not fixed to the stud 7, so it is effective to widen the horizontal width W11a of the vertical portion 11a. In the arrangement shown in Figure 3(c), by widening the horizontal width W11a of the vertical portion 11a in the direction opposite to the side corresponding to the riser, it is possible to efficiently use a single rectangular plate material while improving strength.

[0039] In other words, the length of the top edge of the horizontal part of the tread support is determined by the outer periphery width of the tread, which is designed to meet the standard required for the width of the tread surface, so the position of the vertical edge that contacts this (the right edge in the figure) basically cannot be moved, but the left edge of the vertical edge that is not subject to this restriction can be moved. Details of how to arrange the tread support on the rectangular plate material will be explained later.

[0040] The support structure for a spiral staircase according to the first embodiment is a spiral staircase support structure in which the outer edges of the treads 10 are supported by tread holders 11, 12 in a spiral staircase 100, which is composed of a staircase chamber surrounded by an inner column 6 and multiple outer columns 1, 2, 3, 4, and 5, and in which multiple treads 10 are arranged in different directions. The tread holders 11, 12 have vertical sections 11a, 12a, and upper horizontal sections 11b, 12b and lower horizontal sections 11c, 12c that extend in opposite directions from the upper and lower ends of the vertical sections 11a, 12a. This reduces the amount of material used by the space below the upper horizontal sections 11b, 12b and above the lower horizontal sections 11c, 12c. Furthermore, because the structure is made of a single plate, it is easy to manufacture without the need to combine multiple components. Furthermore, the horizontal lengths L11, L12 of the step board supports 11, 12 are approximately the same as the distance D between the adjacent outer posts, so the left and right ends can be fixed to the outer posts without any waste.

[0041] Furthermore, by making the horizontal width W11a of the vertical portion 11a wider than the vertical widths of the upper horizontal portion 11b and the lower horizontal portion 11c, the strength of the tread support 11 can be increased to withstand loads even when the vertical portion 11a cannot be fixed to the partition 7 provided between adjacent outer columns 1 and 2.

[0042] Furthermore, by making the horizontal width of the vertical portion 11a 150 mm or more, even if the vertical portion 11a cannot be fixed to the partition 7 provided between the adjacent outer columns 1 and 2, the strength of the tread support 11 can be increased to withstand the load.

[0043] (Embodiment 2) Fig. 4 is an installation diagram showing a spiral staircase 200 according to the second embodiment, Fig. 5 is a perspective view showing the installation state of the tread support base of the spiral staircase 200, and Fig. 6 is a front view showing the tread support base of the spiral staircase 200. Note that the same components as those of the spiral staircase 100 according to the first embodiment are given the same reference numerals and their explanations will be omitted. The same functions and effects are also applicable.

[0044] The spiral staircase 200 is a staircase room surrounded by an inner column 6 and outer columns 1, 2, 3, 4, and 5, and has four treads 20a, 20b, 20c, and 20d (hereinafter also referred to as "treads 20") arranged in a counterclockwise direction, changing direction by 180 degrees from the lower floor to the upper floor.

[0045] The inner edge of the tread 20 is fixed to and supported by the inner column 6. Meanwhile, the outer edge of the tread 20 is supported by tread holders 21, 22 arranged in a stepped pattern along the outer columns 1, 2, 3, 4, 5. The spiral staircase 200 according to the second embodiment is made up of four 180-degree steps, but the first half of the treads 20a, 20b and the second half of the treads 20c, 20d are both made up of the same two 90-degree steps, so only the first half will be described below.

[0046] The treads 20a, 20b are shaped to have two 90-degree steps so as to meet the uniformity of the rise height and tread width regulated by the Building Standards Act.

[0047] A step support 21 is attached between the outer columns 1 and 2. The lower end of the step support 21 is fixed to the outer column 1, and a riser 23 is fixed below that. The upper end of the step support 21 is fixed to a support column 8 attached to the outer column 2. The horizontal part of the step support 21 (described later) is fixed to a stud 7 between the outer columns 1 and 2.

[0048] A step support 22 is attached between the outer columns 2 and 3. The lower end of the step support 22 is fixed to a support column 8 attached to the outer column 2. The upper end of the step support 22 is fixed to the outer column 3, and a riser 23 is fixed above it. The upper horizontal part (described below) of the step support 12 is attached to a stud 7 between the outer columns 2 and 3.

[0049] As shown in Figures 3 and 4, the horizontal portion of the step support 21 supports the outer edge of the step 20a, and the upper horizontal portion of the step support 22 supports the outer edge of the step 20b.

[0050] Next, the step board supports 21 and 22 will be described in detail. Fig. 6(a) is a front view of the step board support 21. Fig. 6(b) is a front view of the step board support 22. The ends of each member are shaped to match the members to be joined.

[0051] The step support 21 is made of a single plate having a horizontal portion 21b, and the vertical width of the horizontal portion 21b is W21b. The horizontal length L21 of the step support 21 is approximately the same as the distance D between adjacent outer posts shown in Figure 4.

[0052] The step support 22 is composed of a single plate having a vertical portion 22a and an upper horizontal portion 22b and a lower horizontal portion 22c that extend in opposite directions from the upper and lower ends of the vertical portion 22a. The horizontal length L22 of the step support 22 is approximately the same as the distance D between adjacent outer columns shown in Figure 4. Note that if the lower horizontal portion 22c is not shaped for joining, its lower end surface will be the same as the lower end surface of the vertical portion, and so its vertical width W22c will be as shown in the figure.

[0053] The horizontal width W22a of the vertical portion 22a is preferably wider than the vertical width W22b of the upper horizontal portion 22b and the vertical width W22c of the lower horizontal portion 22c. The horizontal width W22a of the vertical portion 22a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads.

[0054] Figure 6(c) shows the state in which a single rectangular plate is arranged to manufacture the tread support bases 21, 22 and riser member 23. The horizontal length L20 of the rectangular plate is approximately the same as the distance D between adjacent outer columns shown in Figure 4. In the arrangement shown in Figure 6(c), the horizontal width W22a of the vertical portion 22a of the tread support base 22 is widened in the opposite direction to the side corresponding to the riser, thereby improving strength and efficiently utilizing a single rectangular plate.

[0055] (Embodiment 3) 7 is a fitting diagram showing a spiral staircase 300 according to the third embodiment, FIG. 8 is a perspective view showing the mounting state of the step support of the spiral staircase 300, and FIG. 9 is a front view showing the step support of the spiral staircase 300.

[0056] The spiral staircase 300 is a staircase room surrounded by an inner column 6 and outer columns 1, 2, 3, 4, and 5, and has five treads 30a, 30b, 30c, 30d, and 30e (hereinafter also referred to as "treads 30") arranged in a counterclockwise direction, changing direction by 180 degrees from the lower floor to the upper floor.

[0057] The inner edge of the tread 30 is fixed to and supported by the inner pillar 6. On the other hand, the outer edge of the tread 30 is supported by step supports 31, 32, 33, and 34 arranged in a stepped pattern along the outer pillars 1, 2, 3, 4, and 5.

[0058] The treads 30a, 30b, 30c, 30d, and 30e are shaped to have five 180-degree steps so as to meet the uniform rise height and tread width regulated by the Building Standards Act.

[0059] A step support 31 is attached between the outer columns 1 and 2. The lower end of the step support 31 is fixed to the outer column 1, and a riser 35 is fixed below that. The upper end of the step support 31 is fixed to a support column 8 attached to the outer column 2. The lower horizontal part of the step support 31 (described later) is fixed to a stud 7 between the outer columns 1 and 2.

[0060] A step support 32 is attached between the outer columns 2 and 3. The lower end of the step support 32 is fixed to a support column 8 attached to the outer column 2. The upper end of the step support 32 is fixed to the outer column 3. The lower horizontal part (described below) of the step support 32 is attached to a stud 7 between the outer columns 2 and 3.

[0061] A step support 33 is attached between the outer columns 3 and 4. The lower end of the step support 33 is attached to the outer column 3. The upper end of the step support 33 is fixed to a support column 8 attached to the outer column 4. The vertical part of the step support 33 (described later) is attached to a stud 7 between the outer columns 3 and 4.

[0062] A step support 34 is attached between the outer columns 4, 5. The lower end of the step support 34 is fixed to a support column 8 attached to the outer column 4. The upper end of the step support 34 is fixed to the outer column 5. The vertical portion (described below) of the step support 34 is attached to a stud 7 between the outer columns 4, 5. For convenience in creating the drawing, the height position of the step support 34 (left and right direction in the drawing) is shown lower than it actually is.

[0063] As shown in Figures 7 and 8, the lower horizontal portion of step support base 31 supports the outer edge of step 30a, the upper horizontal portion of step support base 31 and the lower horizontal portion of step support base 32 support the outer edge of step 20b, the upper horizontal portion of step support base 32 and the lower horizontal portion of step support base 33 support the outer edge of step 20c, the upper horizontal portion of step support base 33 and the lower horizontal portion of step support base 34 support the outer edge of step 20d, and the upper horizontal portion of step support base 34 supports the outer edge of step 30e.

[0064] Next, the step board supports 31, 32, 33, and 34 will be described in detail. Fig. 9(a) is a front view of step board support 31. Fig. 9(b) is a front view of step board support 33. Fig. 9(d) is a front view of step board support 32. Fig. 9(e) is a front view of step board support 34. The ends of each member are shaped to match the members to be joined.

[0065] The step board support 31 is composed of a single plate having a vertical portion 31a and an upper horizontal portion 31b and a lower horizontal portion 31c that extend in opposite directions from the upper and lower ends of the vertical portion 31a. The horizontal length L31 of the step board support 31 is approximately the same as the distance D between adjacent outer posts shown in Figure 7.

[0066] The horizontal width W31a of the vertical portion 31a is preferably wider than the vertical width W31b of the upper horizontal portion 31b and the vertical width W31c of the lower horizontal portion 31c. The horizontal width W31a of the vertical portion 31a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads.

[0067] The step board support 32 is composed of a single plate having a vertical portion 32a and an upper horizontal portion 32b and a lower horizontal portion 32c that extend in opposite directions from the upper and lower ends of the vertical portion 32a. The horizontal length L32 of the step board support 32 is approximately the same as the distance D between adjacent outer posts shown in Figure 7.

[0068] The horizontal width W32a of the vertical portion 32a is preferably wider than the vertical width W32b of the upper horizontal portion 32b and the vertical width W32c of the lower horizontal portion 32c. The horizontal width W32a of the vertical portion 32a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads.

[0069] The step board support 33 is composed of a single plate having a vertical portion 33a and an upper horizontal portion 33b and a lower horizontal portion 33c that extend in opposite directions from the upper and lower ends of the vertical portion 33a. The horizontal length L33 of the step board support 33 is approximately the same as the distance D between adjacent outer posts shown in Figure 7.

[0070] The horizontal width W33a of the vertical portion 33a is preferably wider than the vertical width W33b of the upper horizontal portion 33b and the vertical width W33c of the lower horizontal portion 33c. The horizontal width W33a of the vertical portion 33a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads.

[0071] The step support 34 is composed of a single plate having a vertical portion 34a and an upper horizontal portion 34b and a lower horizontal portion 34c that extend in opposite directions from the upper and lower ends of the vertical portion 34a. The horizontal length L34 of the step support 34 is approximately the same as the distance D between adjacent outer posts shown in Figure 7.

[0072] The horizontal width W34a of the vertical portion 34a is preferably wider than the vertical width W34b of the upper horizontal portion 34b and the vertical width W34c of the lower horizontal portion 34c. The horizontal width W34a of the vertical portion 34a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads.

[0073] Here, the tread support bases 31, 32 and the tread support bases 33, 34 are fixed to the studs 7 between the outer columns at different positions. That is, the lower horizontal portions 31c, 32c of the tread support bases 31, 32 are fixed to the studs 7, while the vertical portions 33a, 34a of the tread support bases 33, 34 are fixed to the studs 7. As a result, the tread support bases 33, 34 in which the lower horizontal portions 31c, 32c are fixed to the studs 7 are less able to withstand vertical loads than the tread support bases 33, 34 in which the vertical portions 33a, 34a are fixed to the studs 7. For this reason, when the tread support bases 33, 34 are fixed to the studs 7 at their respective positions, it is more effective to increase the horizontal width of the vertical portions.

[0074] Figure 9(c) shows the state in which the step holders 31, 33 are arranged on a single rectangular plate material in order to manufacture them. The horizontal length L30 of the rectangular plate material is approximately the same as the distance D between adjacent outer columns shown in Figure 7. When arranging the two step holders, at least two pairs of horizontal sides of the two step holders are arranged adjacent to each other, and then two step holders are cut out from this state. Specifically, the upper edge of the upper horizontal portion 31b of the step holder 31 is adjacent to the lower edge of the upper horizontal portion 33b of the step holder 33, and the upper edge of the lower horizontal portion 31c of the step holder 31 is adjacent to the lower edge of the lower horizontal portion 33c of the step holder 33.

[0075] As mentioned above, of the tread support bases 31 and 33, the vertical portion 31a of the tread support base 31 is not fixed to the stud 7, so it is effective to widen the horizontal width W31a of the vertical portion 31a. In the arrangement shown in Figure 9(c), by widening the horizontal width W31a of the vertical portion 31a in the direction opposite to the side corresponding to the riser, it is possible to efficiently use a single rectangular plate material while improving strength.

[0076] Figure 9(f) shows the state in which the step holders 32, 34 are arranged on a single rectangular plate material in order to manufacture them. The horizontal length L30 of the rectangular plate material is approximately the same as the distance D between adjacent outer columns shown in Figure 7. When arranging the two step holders, at least two pairs of horizontal sides of the two step holders are arranged adjacent to each other, and then two step holders are cut out from this state. Specifically, the upper edge of the upper horizontal portion 32b of the step holder 32 is adjacent to the lower edge of the upper horizontal portion 34b of the step holder 34, and the upper edge of the lower horizontal portion 32c of the step holder 32 is adjacent to the lower edge of the lower horizontal portion 34c of the step holder 34.

[0077] Here, which of the step board supports 31, 32, 33, and 34 should be combined and arranged on one rectangular plate material can be arranged in a state where the vertical part can be expanded by combining step board supports 31 and 32, which have their vertical part shifted to one side, with step board supports 33 and 34, which are in the center. This can also be done in the other embodiments described below.

[0078] As mentioned above, of the tread support bases 32, 34, the vertical portion 32a of the tread support base 32 is not fixed to the stud 7, so it is effective to widen the horizontal width W32a of the vertical portion 32a. In the arrangement shown in Figure 9(g), by widening the horizontal width W32a of the vertical portion 32a in the direction opposite to the side corresponding to the riser, it is possible to efficiently use a single rectangular plate material while improving strength.

[0079] (Embodiment 4) 10 is a fitting diagram showing a spiral staircase 400 according to the fourth embodiment, FIG. 11 is a perspective view showing the mounting state of the step support of the spiral staircase 400, and FIG. 12 is a front view showing the step support of the spiral staircase 400.

[0080] The spiral staircase 400 is a staircase room surrounded by an inner column 6 and outer columns 1, 2, 3, 4, and 5, and has seven treads 40a, 40b, 40c, 40d, 40e, 40f, and 40g (hereinafter also referred to as "treads 40") arranged in a counterclockwise direction, changing direction by 180 degrees from the lower floor to the upper floor.

[0081] The inner edge of the tread 40 is fixed to and supported by the inner pillar 6. On the other hand, the outer edge of the tread 40 is supported by step supports 41, 42, 43, and 44 arranged in a stepped pattern along the outer pillars 1, 2, 3, 4, and 5.

[0082] The treads 40a, 40b, 40c, 40d, 40e, 40f, and 40g are shaped to have seven steps of 180 degrees so as to meet the uniform rise height and tread width regulated by the Building Standards Act.

[0083] A step support 41 is attached between the outer columns 1 and 2. The lower end of the step support 41 is fixed to the outer column 1, and a riser 45 is fixed below that. The upper end of the step support 41 is fixed to a support column 8 attached to the outer column 2. The vertical part of the step support 41 (described later) is fixed to a stud 7 between the outer columns 1 and 2.

[0084] A step support 42 is attached between the outer columns 2 and 3. The lower end of the step support 42 is fixed to a support column 8 attached to the outer column 2. The upper end of the step support 42 is fixed to the outer column 3. The upper horizontal part (described later) of the step support 42 is attached to a stud 7 between the outer columns 2 and 3.

[0085] A step support 43 is attached between the outer columns 3 and 4. The lower end of the step support 43 is attached to the outer column 3. The upper end of the step support 43 is fixed to a support column 8 attached to the outer column 4. The upper horizontal part (described below) of the step support 43 is attached to a stud 7 between the outer columns 3 and 4.

[0086] A step support 44 is attached between the outer columns 4, 5. The lower end of the step support 44 is fixed to a support column 8 attached to the outer column 4. The upper end of the step support 44 is fixed to the outer column 5. The lower horizontal portion (described below) of the step support 44 is attached to a stud 7 between the outer columns 4, 5. For convenience in creating the drawing, the height position of the step support 44 (left and right direction in the drawing) is shown lower than it actually is.

[0087] As shown in Figures 10 and 11, the lower horizontal portion of step support base 41 supports the outer edge of step 40a, the upper horizontal portion of step support base 41 and the lower horizontal portion of step support base 42 support the outer edge of step 40b, the upper horizontal portion of step support base 42 supports the outer edge of step 40c, the vertical portion of step support base 42 and the lower horizontal portion of step support base 43 support the outer edge of step 40d, the upper horizontal portion of step support base 43 supports the outer edge of step 40e, the upper vertical portion of step support base 43 and the lower horizontal portion of step support base 44 support the outer edge of step 40f, and the upper horizontal portion of step support base 44 supports the outer edge of step 40g.

[0088] Next, the step board supports 41, 42, 43, and 44 will be described in detail. Fig. 12(a) is a front view showing the step board support 41. Fig. 12(b) is a front view showing the step board support 42. Fig. 12(d) is a front view showing the step board support 43. Fig. 12(e) is a front view showing the step board support 44. The ends of each member are shaped to match the members to be joined.

[0089] The step board support 41 is composed of a single plate having a vertical portion 41a and an upper horizontal portion 41b and a lower horizontal portion 41c that extend in opposite directions from the upper and lower ends of the vertical portion 41a. The horizontal length L41 of the step board support 41 is approximately the same as the distance D between adjacent outer posts shown in Figure 10.

[0090] The horizontal width W41a of the vertical portion 41a is preferably wider than the vertical width W41b of the upper horizontal portion 41b and the vertical width W41c of the lower horizontal portion 41c. The horizontal width W41a of the vertical portion 41a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads.

[0091] The step support 42 is composed of a single plate having a vertical portion 42a, an upper horizontal portion 42b and a lower horizontal portion 42c that extend in opposite directions from the upper and lower ends of the vertical portion 42a, an upper vertical portion 42d that extends upward from the end of the upper horizontal portion 42b, and an upper horizontal portion 42e that extends to the left from the top end of the upper vertical portion 42d. The horizontal length L42 of the step support 42 is approximately the same as the distance D between adjacent outer posts shown in Figure 10.

[0092] The horizontal width W42a of the vertical portion 42a is preferably wider than the vertical width W42b of the upper horizontal portion 42b and the vertical width W42c of the lower horizontal portion 42c. The horizontal width W42a of the vertical portion 42a is preferably 150 mm or greater, and more preferably 180 mm or greater. This makes it easier to support vertical loads. The same applies to the horizontal width W42d of the upper vertical portion 42d.

[0093] The step board support 43 is composed of a single plate having a vertical portion 43a, an upper horizontal portion 43b and a lower horizontal portion 43c that extend in opposite directions from the upper and lower ends of the vertical portion 43a, and an upper vertical portion 43d that extends upward from the end of the upper horizontal portion 43b. The horizontal length L43 of the step board support 43 is approximately the same as the distance D between adjacent outer posts shown in Figure 10.

[0094] The horizontal width W43a of the vertical portion 43a is preferably wider than the vertical width W43b of the upper horizontal portion 43b and the vertical width W43c of the lower horizontal portion 43c. The horizontal width W43a of the vertical portion 43a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads. The same applies to the horizontal width W43d of the upper vertical portion 43d.

[0095] The step support 44 is made up of a single plate having a vertical portion 44a and an upper horizontal portion 44b and a lower horizontal portion 44c that extend in opposite directions from the upper and lower ends of the vertical portion 44a. The horizontal length L44 of the step support 44 is approximately the same as the distance D between adjacent outer posts shown in Figure 10.

[0096] The horizontal width W44a of the vertical portion 44a is preferably wider than the vertical width W44b of the upper horizontal portion 44b and the vertical width W44c of the lower horizontal portion 44c. The horizontal width W44a of the vertical portion 44a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads.

[0097] Here, the positions at which the step holders 42, 43, 44 and the step holder 41 are fixed to the studs 7 between the outer columns are different. That is, the upper horizontal portions 42b, 43b and the lower horizontal portion 44c of the step holders 42, 43, 44 are fixed to the studs 7, while the vertical portion 41a of the step holder 41 is fixed to the stud 7. As a result, the step holders 42, 43, 44, whose upper horizontal portions 42b, 43b and lower horizontal portion 44c are fixed to the stud 7, are less able to withstand vertical loads than the step holder 41, whose vertical portion 41a is fixed to the stud 7. For this reason, when the step holders 42, 43, 44 are fixed to the studs 7 in the same positions, it is more effective to increase the horizontal width of the vertical portions.

[0098] Figure 12(c) shows the state in which the step holders 41, 42 are arranged on a single rectangular plate material in order to manufacture them. The horizontal length L40 of the rectangular plate material is approximately the same as the distance D between adjacent outer columns shown in Figure 10. When arranging the two step holders, at least two pairs of horizontal sides of the two step holders are arranged adjacent to each other, and then the two step holders are cut out from this state. Specifically, the upper side of the upper horizontal portion 41b of the step holder 41 is adjacent to the lower side of the upper horizontal portion 42b of the step holder 42, and the upper side of the lower horizontal portion 41c of the step holder 41 is adjacent to the lower side of the lower horizontal portion 42c of the step holder 42.

[0099] As mentioned above, of the tread support bases 41, 42, the vertical portion 42a of the tread support base 42 is not fixed to the stud 7, so it is effective to widen the horizontal width W42a of the vertical portion 42a. In the arrangement shown in Figure 12(d), by widening the horizontal width W42a of the vertical portion 42a in the direction opposite to the side corresponding to the riser, it is possible to efficiently use a single rectangular plate material while improving strength.

[0100] Figure 12(f) shows the state in which the step holders 43, 44 are arranged on a single rectangular plate material in order to manufacture them. The horizontal length L40 of the rectangular plate material is approximately the same as the distance D between adjacent outer columns shown in Figure 10. When arranging the two step holders, at least two pairs of horizontal sides of the two step holders are arranged adjacent to each other, and then the two step holders are cut out. Specifically, the upper side of the upper horizontal portion 43b of the step holder 43 and the lower side of the lower horizontal portion 44c of the step holder 44 are arranged adjacent to each other.

[0101] As mentioned above, because the vertical portions 43a, 44a of the tread support bases 43, 44 are not fixed to the studs 7, it is effective to widen the horizontal widths W43a, W44a of the vertical portions 43a, 44a. In the arrangement shown in Figure 12(f), the horizontal width W43a of the vertical portion 43a and the horizontal width W44a of the vertical portion 44a are widened in the direction opposite to the side corresponding to the riser, thereby improving strength and efficiently utilizing a single rectangular plate material.

[0102] (Embodiment 5) 13 is a fitting diagram showing a spiral staircase 500 according to the fifth embodiment, FIG. 14 is a perspective view showing the mounting state of the step support of the spiral staircase 500, and FIG. 15 is a front view showing the step support of the spiral staircase 500.

[0103] The spiral staircase 500 is a staircase room surrounded by an inner column 6 and outer columns 1, 2, 3, 4, and 5, and has eight treads 50a, 50b, 50c, 50d, 50e, 50f, 50g, and 50h (hereinafter also referred to as "treads 50") arranged in a counterclockwise direction, changing direction by 180 degrees from the lower floor to the upper floor.

[0104] The inner edge of the tread 50 is fixed to and supported by the inner column 6. Meanwhile, the outer edge of the tread 50 is supported by tread holders 51, 52, 53, and 54 arranged in a stepped pattern along the outer columns 1, 2, 3, 4, and 5. The spiral staircase 500 according to the fifth embodiment is composed of eight 180-degree steps, but the first half of the treads 50a, 50b, 50c, and 50d and the second half of the treads 50e, 50f, 50g, and 50h all have the same configuration of four 90-degree steps, so only the first half will be described below.

[0105] The treads 50a, 50b, 50c, and 50d are shaped to have four 90-degree steps so as to meet the uniform rise height and tread width regulated by the Building Standards Act.

[0106] A step support 51 is attached between the outer columns 1 and 2. The lower end of the step support 51 is fixed to the outer column 1, and a riser 55 is fixed below that. The upper end of the step support 51 is fixed to a support column 8 attached to the outer column 2. The vertical part of the step support 51 (described later) is fixed to a stud 7 between the outer columns 1 and 2.

[0107] A step support 52 is attached between the outer columns 2 and 3. The lower end of the step support 52 is fixed to a support column 8 attached to the outer column 2. The upper end of the step support 52 is fixed to the outer column 3. The lower horizontal part (described later) of the step support 52 is attached to a stud 7 between the outer columns 2 and 3.

[0108] As shown in Figures 13 and 14, the lower horizontal part of the step support base 51 supports the outer edge of step 50a, the upper horizontal part of the step support base 51 supports the outer edge of step 50b, the lower horizontal part of the step support base 52 supports the outer edge of step 50c, and the upper horizontal part of the step support base 52 supports the outer edge of step 50d.

[0109] Next, the step board supports 51 and 52 will be described in detail. Fig. 15(a) is a front view of the step board support 51. Fig. 15(b) is a front view of the step board support 52. The ends of each member are shaped to match the members to be joined.

[0110] The step board support 51 is made up of a single plate having a vertical portion 51a and an upper horizontal portion 51b and a lower horizontal portion 51c that extend in opposite directions from the upper and lower ends of the vertical portion 51a. The horizontal length L51 of the step board support 51 is approximately the same as the distance D between adjacent outer posts shown in Figure 13.

[0111] The horizontal width W51a of the vertical portion 51a is preferably wider than the vertical width W51b of the upper horizontal portion 51b and the vertical width W51c of the lower horizontal portion 51c. The horizontal width W51a of the vertical portion 51a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads.

[0112] The step support 52 is composed of a single plate having a vertical portion 52a, an upper horizontal portion 52b and a lower horizontal portion 52c that extend in opposite directions from the upper and lower ends of the vertical portion 52a, a lower vertical portion 52d that extends downward from the end of the lower horizontal portion 52c, and a lower horizontal portion 52e that extends to the right from the lower end of the lower vertical portion 52d. The horizontal length L52 of the step support 52 is approximately the same as the distance D between adjacent outer posts shown in Figure 13.

[0113] The horizontal width W52a of the vertical portion 52a is preferably wider than the vertical width W52b of the upper horizontal portion 52b and the vertical width W52c of the lower horizontal portion 52c. The horizontal width W52a of the vertical portion 52a is preferably 150 mm or more, and more preferably 180 mm or more. This makes it easier to support vertical loads. The same applies to the horizontal width W52d of the lower vertical portion 52d.

[0114] Here, the positions at which tread support base 51 and tread support base 52 are fixed to the studs 7 between the outer columns are different. That is, tread support base 52 has its lower horizontal portion 52c fixed to the stud 7, while tread support base 51 has its vertical portion 51a fixed to the stud 7. As a result, tread support base 52, whose lower horizontal portion 52c is fixed to the stud 7, is less able to withstand vertical loads than tread support base 51, whose vertical portion 51a is fixed to the stud 7. For this reason, when the tread support base is fixed in a position like tread support base 52, it is more effective to increase the horizontal width of the vertical portion.

[0115] Figure 15(c) shows the state in which the step holders 51, 52 are arranged on a single rectangular plate material in order to manufacture them. The horizontal length L50 of the rectangular plate material is approximately the same as the distance D between adjacent outer columns shown in Figure 13. When arranging the two step holders, at least two pairs of horizontal sides of the two step holders are arranged adjacent to each other, and then the two step holders are cut out. Specifically, the upper side of the upper horizontal portion 51b of the step holder 51 and the lower side of the lower horizontal portion 52c of the step holder 52 are arranged adjacent to each other.

[0116] As mentioned above, of the tread support bases 51, 52, the vertical portion 52a of the tread support base 52 is not fixed to the stud 7, so it is effective to widen the horizontal width W52a of the vertical portion 52a. In the arrangement shown in Figure 15(d), by widening the horizontal width W52a of the vertical portion 52a in the direction opposite to the side corresponding to the riser, it is possible to efficiently use a single rectangular plate material while improving strength.

[0117] The method for arranging step supports on rectangular plates (design procedures) will be described in detail below with reference to Figures 16 and 17, using the step supports of Embodiments 1 and 4 of the present application as examples. Here, we will use a 910 module design as an example, and describe a design using a column spacing (center-to-center spacing) of 910 mm, standard plate materials that form the basis for the rectangular plates, measuring 910 mm x 1820 mm or 910 mm x 2730 mm, and a plate thickness of 24 mm (hereinafter, mm will be omitted). These are standard designs and materials, and using them will save extra costs.

[0118] By configuring a 910mm column spacing with a single plate tread base, the spiral staircase uses two tread bases for a 90-degree turn and four tread bases for a 180-degree turn. Since building stairs are designed and delivered to each site, it is easier to respond quickly to individual designs by producing and shipping two tread bases for use within 90 degrees or four tread bases for use within 180 degrees for each building order. Therefore, by taking two tread bases that make up the smallest unit of 90 degrees from one rectangular plate, efficient inventory management of rectangular plate materials is also possible. It is best to think of a 180-degree turn as two 90-degree turns.

[0119] The step support of embodiment 1 will be described with reference to Figure 16. First, a standard board material of 910 x 1820, with the same width as the column spacing, is cut into four pieces of 910 x 450, which are the size of rectangular board material A. If the rise height of the staircase is 230 mm or less as required by the Building Standards Act and the vertical width of the horizontal part is 100 mm, and the cutting width is 20 mm or less, the step support can be placed if there is one vertical part on the step support.

[0120] Two step support pedestals are placed here. In this case, a vertical section is temporarily set to the same width as the horizontal section, and the upper step support 12' is placed to the right, and the lower step support 11' is placed to the left. In this case, the upper and lower positions are selected so that there is no interference with the vertical sections. This state is shown in Figure 16(a). Step support 11' corresponds to step support 11, and step support 12' corresponds to step support 12.

[0121] The tread support base of a spiral staircase is designed using various techniques, such as shifting the axis of the center shaft, to ensure the effective tread surface of the spiral staircase tread, and the resulting tread length on the outer periphery cannot be easily changed. Therefore, as a rule, adjustments to change the dimensions of the upper surface of the tread support base on which the tread rests are not made. Also, since the rise height of a single staircase must be uniform, the length of the surface (edge) corresponding to the so-called riser cannot be changed. The surfaces (edges) whose length cannot be changed are shown in bold in Figure 16(b).

[0122] In this application, in order to widen the vertical section to ensure strength and attach it to a stud, the sides with room to widen the vertical section from the arrangement in Figure 16(a) are sides 11y and 12y opposite sides 11x and 12x that correspond to the riser of the tread support, and these are widened in the direction of the arrow shown in Figure 16(b). In this case, as mentioned above, ensuring a width of 150 mm or more, more preferably 180 mm or more, will enable it to withstand the tread load.

[0123] However, even if there is room for widening, widening the width will increase the area of ​​the finished tread support, resulting in increased weight and transportation costs, and will also increase restrictions on the use of the space under the stairs, such as restrictions on the placement and height of windows, so it is preferable to take these factors into consideration and set the width appropriately within the range that will allow for strength.In other words, it is preferable to limit the widening of the vertical sections sandwiched between the horizontal sections to a range that does not reach the pillars on the side in the widening direction.

[0124] As mentioned above, the step support base is also roughly the same length as the column spacing, and even if it is moved to the left or right, it still takes up most of the width. Step support base 12 in Figure 1 runs from the left side of column 3 to the left side of column 2, and its length is the same as the column spacing D. Step support base 11 runs from the right end of column 4 to roughly the center of column 3 (depending on the shape and design of the surrounding step), and is shorter than D by about half the thickness of the column. Therefore, when step support base 11 is placed under rectangular plate material A, moving it to the left end as shown in Figure 16(a) leaves the right end free, and there is also a margin on the right side of the vertical section. This ensures the width of the vertical section.

[0125] In contrast, for example, the mating ends of the tread support bases 33 and 34 in Figure 7 are designed to be longer than the center of the pillar 3, so that the tread surface is flat after joining. Therefore, the length is closer to the pillar spacing D, making it less likely that a gap will be created. By not processing the shapes of the surfaces of these contacting ends to match the parts that will be joined together, it is possible to design them in a way that ensures a longer gap.

[0126] As a result of the widening shown in FIG. 16(b), the final cutting arrangement is as shown in FIG. 16(c).

[0127] 17(d), it may be possible to rotate one of the step support bases 11 so that the faces (sides) whose lengths cannot be changed face each other. In this case, the width is increased by the sides 11y and 12y opposite the sides 11x and 12x corresponding to the risers, but this has the advantage that the amount of width increase is not restricted by the position of the other step support base. In this case too, the amount of width increase can be determined within the aforementioned restrictions.

[0128] However, if the components are rotated, it may be difficult for the operator to distinguish between up and down during manufacturing, and there may be inconsistencies that require attention, such as the direction of the part number markings on the components, the direction of marking when installing the components, and the direction when packaging, which may not be desirable in terms of production efficiency. Therefore, the arrangement shown in Figure 16(c) is more preferable.

[0129] Referring to Figure 17, the step support of embodiment 4 will be described. First, a standard 910 x 2730mm board with the same width as the column spacing is divided into four sections, resulting in a rectangular board B measuring 910 x 680mm. If the rise height of the staircase is 230mm or less as required by the Building Standards Act and the vertical width of the horizontal section is 100mm, and the cutting width is 20mm or less, a step support can be placed on one side of the step support with two vertical sections. All of the above-mentioned embodiments can be combined with a step support with two vertical sections and one vertical section. Even if there are two step support with two vertical sections at 180 degrees as shown in Figure 12, by combining it with another step support with one vertical section, a compatible arrangement can be achieved, as shown in Figures 12(c) and 12(f).

[0130] Two step support bases are placed here. At this time, a vertical section with the same width as the horizontal section is temporarily set, and the upper step support base 42' is placed to the right, and the lower step support base 41' is placed to the left. At this time, the upper and lower positions are selected so that there is no interference with the vertical sections. This state is shown in Figure 17(a). Step support base 41' corresponds to step support base 41, and step support base 42' corresponds to step support base 42.

[0131] The restrictions and procedures for this widening are the same as those described above, which allows for the widening shown in Figure 17(b). In this case, the widening of the upper vertical portion 42d of the step support 42 causes most of the upper horizontal portion 42e to be included in the upper vertical portion 42d. Here, referring to the position of the step support 42 in Figure 10, it can be seen that this widening allows the upper vertical portion 42d to hang on the pillar 3, making it possible for the upper vertical portion 42d to be joined to the pillar.

[0132] In this way, when the tread support base has an upper vertical section extending upward from the end of the upper horizontal section, the strength of the tread support base can be improved by widening the horizontal width of the upper vertical section in the direction opposite to the side corresponding to the riser, making it wide enough to be fixed to a pillar such as an outer column, a support column, or a partition column. The same applies when there is a lower vertical section extending downward from the end of the lower horizontal section.

[0133] As mentioned above, the rectangular plate material sizes are 450 and 680, and the tread support bases are positioned vertically along the top and bottom edges. This makes it possible to simultaneously finish two component edges in one cut with a fixed cutting width of 20 mm for a staircase with a riser height of 230 mm, making this size optimal for production. Also, by widening the opposing vertical edges so that they are 20 mm apart when widened, this part can also be cut in one go with the cutter, making it optimal. Figure 16(c) shows such widening.

[0134] Furthermore, the upper and lower sides are the sides of a rectangular plate, and if the rectangular plate is prepared in advance, there is no need to cut those sides when manufacturing the step support base, so the cutting process time after an order is reduced and parts can be produced and shipped quickly, making it possible to ship quickly even in the case of made-to-order production. The same effect can be expected by positioning each step support base at the left and right ends.

[0135] The width of the material cut out for the step support is approximately the same as the distance between the posts (in the above cases, 910). This, along with the above arrangement, reduces waste material and reduces the amount of waste. In addition, by placing other staircase parts, such as riser material 13, in the remaining rectangular part and cutting them out at the same time, waste can be further reduced.

[0136] Furthermore, if we take into consideration the size error of rectangular plates due to the cutting section when dividing a standard plate into four pieces, it goes without saying that this can be accommodated by changing the cutting width of the router by 20 mm and designing the production equipment accordingly.

[0137] If the rise height is less than 230 mm, by first cutting a rectangular plate material of size 450 or 680 to the desired size using a running saw or similar, the step support can be cut out in a shorter time than if the entire piece were manufactured using a running saw or similar tool, taking into account the speed of the running saw and the speed of the router.

[0138] Furthermore, when the design module is a meter module, it can be similarly designed and manufactured by using meter-sized items as the column spacing and standard plate material.

[0139] In this way, according to the support structure for a spiral staircase according to this embodiment (embodiments 1-5), it is possible to achieve cost reduction while overcoming the design constraints of the tread support base.

[0140] In this application, the vertical section was widened. One of the reasons for this is that, when the space under the stairs is used as a living room, toilet, storage room, etc., it is easier to ensure a higher ceiling or to install window frames at a higher position compared to when the horizontal section is widened. Also, when the number of studs is increased, a wider vertical surface will provide greater overlap with the reinforcing base (studs), increasing strength.

[0141] The support structure for a spiral staircase according to the embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and various other modifications are possible.

[0142] For example, the end portions of each member of the step support are shown as being shaped to match the members to be joined, but the ends can also be butted together without any processing, or can be processed into a miter joint.

[0143] Also, the description here is for a design in which the support base is fixed directly to the pillars of the staircase, and the length of the support base is related to the dimension D of the pillar spacing (center-to-center spacing), but in addition to this, there are also cases where, for structural reasons, wall materials such as gypsum board or furring strips are sandwiched between the pillars and the support base, in which case the length of the support base is adjusted in the design to be shorter by the thickness of these materials, but the thickness of the wall material is thinner than D and can be said to be roughly within the dimension D, and there is some leeway in the design of the placement and widening of the step support base on the rectangular plate material.

[0144] In addition, in the above embodiment, it was described that the inner edge of the tread is fixed to and supported by the inner post, but this can be achieved by forming a notch in the inner post itself and inserting the tip of the tread into it to fix it, or by fixing a small piece holder to the center post and placing the tread on top of it to fix it.

[0145] In the above embodiment, the arrangement is described as changing direction counterclockwise from the lower floor to the upper floor, but the arrangement may be clockwise from the lower floor to the upper floor. [Explanation of symbols]

[0146] 1 outer column 2 Outer column 3 Outer column 4 Outer column 5 Outer column 6 Inner pillar 7 Studs 8 pillars 10 Treadboard 11 Stepboard cradle 12 Stepboard cradle 13 Keage wood 20 Treadboard 21 Stepboard cradle 22 Stepboard cradle 23 Keage wood 30 Treadboard 31 Stepboard cradle 32 Stepboard cradle 33. Pedal support platform 34. Pedal support platform 35. A talented individual who can kick a ball. 40 pedals 41. Pedal support platform 42. Pedal support platform 43. Pedal support platform 44. Pedal support platform 45. A talented individual who can kick a ball. 50 pedals 51. Pedal support platform 52. Pedal support platform 53. Pedal support platform 54. Pedal support platform 55. A talented individual who can kick a ball. 100-turn stage 200-turn stage 300-turn stage 400 Return Phase 500-turn stage

Claims

1. A spiral staircase in which a plurality of treads are arranged in a staircase surrounded by an inner column and a plurality of outer columns, with the outer edge of the treads supported by a tread support, The support structure for a spiral staircase is characterized in that the tread support is composed of a single plate having a vertical portion and an upper horizontal portion and a lower horizontal portion extending in opposite directions from the upper and lower ends of the vertical portion, and its horizontal length is approximately the same as the distance between adjacent outer columns.

2. 2. The support structure for a spiral staircase according to claim 1, wherein the horizontal width of the vertical portion is wider than the vertical widths of the upper horizontal portion and the lower horizontal portion.

3. 2. The support structure for a spiral staircase according to claim 1, wherein the horizontal width of the vertical portion is 150 mm or more.

4. A staircase having a spiral staircase support structure according to any one of claims 1 to 3.

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