Spiral stairway, design method for spiral stairway, manufacturing method for spiral stairway

Abstract

To increase a degree of freedom in designing a spiral stairway and to reduce construction burden at a construction site while reliably satisfying legal dimensions of a tread surface stipulated by the Building Standards Act even in a residential structure with small pillar dimensions, wall material thickness, and floor area.SOLUTION: In a spiral stairway 1 in plan view, imaginary X-axis and Y-axis are defined with the center 4a of a pillar 4 as an imaginary origin. When a plurality of imaginary lines 30 (31 to 35) are set around the center 4a in a plan view, an end side surface 8a of a nosing 8 of a tread 10 or a riser 7 is positioned on the imaginary lines 31 to 35. Neighboring two of the imaginary lines 31 to 35 define angle ranges θ1 to θ4 of tread surfaces 21 to 24 of the treads 11 to 14. Imaginary lines 32 to 34 disposed midway around the center 4a pass through the center 4a. The angle ranges θ1 to θ4 around the center 4a are not constant. The imaginary line 31 defining the tread surface 21 of the first step tread 11 does not pass through the center 4a of the pillar 4.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a spiral staircase, a spiral staircase design method, and a spiral staircase manufacturing method. [Background technology]

[0002] When placing stairs in a home, the type of staircase is selected appropriately depending on the relative positions of the living rooms and hallways. There are folding stairs that turn 90 degrees in the ascending and descending direction, and folding stairs that turn 180 degrees in the ascending and descending direction. These types of stairs are collectively called spiral staircases. Spiral staircases are effective in homes with small floor space, and are often used.

[0003] Regarding the installation of stairs, the Building Standards Act stipulates that the tread must be at least 150mm. For spiral staircases, the shortest distance (straight line length, tread length) from the position 300mm from the narrow side of the spiral tread (the wall surface on the spiral staircase's column side) to the nosing of the next tread must be at least 150mm. Increasing the number of tread steps is an effective way to ascend and descend stairs in homes with limited floor space, but as mentioned above, it can be difficult to meet the requirement of a tread length of 150mm.

[0004] As mentioned above, spiral staircases have many design constraints, so they also require ingenuity in their design methods. A method for designing spiral staircases, specifically a method for positioning treads, is known, as described in Patent Document 1. Patent Document 1 describes a method for ensuring a tread surface length of 150 mm by moving the center of rotation of the tread, which has a fixed angle around the pillar. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6678409 specification Summary of the Invention [Problem to be solved by the invention]

[0006] In the case of the tread positioning method described in Patent Document 1, the smaller the column dimensions and wall thickness, the farther the center of rotation required to meet the tread length requirement of 150 mm or more moves away from the column, resulting in the first and last steps of the spiral staircase connecting to the straight staircase moving toward the straight staircase. This can affect the design of the straight steps, and depending on the floor area, it may be impossible to ensure sufficient tread space on the straight steps when the spiral staircase requires a tread length of 150 mm or more. For example, in homes constructed with 2x4 or lightweight steel frames, the column dimensions and wall thickness are smaller than in traditional wood-frame construction, making it difficult to design a spiral staircase with a fixed tread angle. Furthermore, the farther the center of rotation moves from the column, the more difficult it becomes to understand the layout of the treads around the column, increasing the tedious work of shifting the center at the spiral staircase construction site.

[0007] Against the above background, the object of the present invention is to provide a spiral staircase, a design method for a spiral staircase, and a manufacturing method for a spiral staircase that can increase the degree of freedom in designing a spiral staircase while reliably meeting the legal dimensions of the treads stipulated by the Building Standards Act even in residential structures with small pillar dimensions, wall material thickness, and floor area, and that can further reduce the construction burden at the construction site. [Means for solving the problem]

[0008] The present invention relates to the following spiral staircase, spiral staircase design method, and spiral staircase manufacturing method.

[0009] (1) In plan view, the center of the pillar is the virtual origin, and the two virtual axes are the virtual X-axis and the virtual Y-axis, which pass through the origin and are perpendicular to each other. a plurality of treads arranged around the pillar; When a plurality of virtual lines are set around the center in a plan view, The end side surface of the nosing of the tread or the riser is disposed on the imaginary line, The two adjacent imaginary lines define an angle range of the tread surface of the tread, one of the plurality of virtual lines is disposed on the virtual axis; Among the plurality of virtual lines, the virtual line disposed at the middle around the center passes through the center, The angular range of the tread surface of each of the treads around the center is not constant, A spiral staircase characterized in that one of the imaginary lines that define the angle range of the tread surface of the tread of the first or last step does not pass through the center of the column.

[0010] (2) The spiral staircase is disposed within a range of 90 degrees or approximately 90 degrees around the center of the column; The spiral staircase described in (1) above, wherein one of the imaginary lines that define the angle range of the tread surface of the tread of the last or first step is positioned on the imaginary axis.

[0011] (3) The spiral staircase is disposed within a range of 180 degrees or approximately 180 degrees around the center of the column; The angular range of the tread surfaces of the two treads in the middle around the center is defined by the imaginary line disposed on the imaginary axis, The spiral staircase described in (1) above, wherein one of the imaginary lines that define the angle range of the tread surface of at least one of the treads of the last step and the first step does not pass through the center of the column.

[0012] (4) The spiral staircase is arranged within a range of 180 degrees or approximately 180 degrees around the center, The spiral staircase described in (1) above, wherein one of the virtual lines defining the angle range of the tread surface of the tread of the last or first step is positioned on the virtual axis, and the virtual line defining the angle range of the tread surface of the tread of the intermediate step is positioned offset from the virtual axis.

[0013] (5) The spiral staircase according to any one of (1) to (4), wherein the imaginary line that does not pass through the center of the pillar is arranged parallel to the imaginary axis.

[0014] (6) A spiral staircase described in any one of (1) to (5), wherein the imaginary line that does not pass through the center of the column has a shift dimension from the center that is less than 1 / 2 of the wall thickness of the column.

[0015] (7) A spiral staircase as described in any one of (1) to (6), wherein the angle range of each of the tread surfaces of the treads is largest for the treads having the tread surfaces divided by the virtual lines arranged on the virtual axis, and the angle range decreases stepwise or continuously for the treads farther from the tread surface with the largest angle range.

[0016] (8) A design method for a spiral staircase having a plurality of treads, in a plan view, in which the center of the pillar is set as a virtual origin, and virtual X-axis and Y-axis that pass through the origin and are perpendicular to each other are set as two virtual axes, 1) determining the dimensions of the pillar and the thickness of the wall material to be placed around the pillar; 2) determining the tread length of each of the treads at a position 300 mm away from the wall surface of the wall material; 3) creating a provisional layout diagram for each tread based on the conditions input in steps 1) and 2); 4) A step of resetting the angle range of each of the tread surfaces in the temporary allocation diagram created in step 3); 5) recalculating the tread length of each of the treads in the angle range of each of the treads reset in step 4); 6) A step of recreating an allocation diagram for each of the treads based on the conditions obtained from steps 4) and 5); A design method for a spiral staircase.

[0017] (9) The method further comprises step 7) of setting a displacement dimension of the first or last step from the center of the column after recalculating the tread length of each step in step 5), The design method for a spiral staircase according to (8) above, wherein in step 6), a layout diagram for each of the treads is recreated from the conditions obtained from steps 4), 5), and 7).

[0018] (10) A method for manufacturing a spiral staircase, in which the treads are manufactured in a shape designed by the design method described in (8) or (9). [Effects of the Invention]

[0019] According to the present invention, even in a residential structure with small pillar dimensions, wall material thickness, and floor area, the legal dimensions of the treads specified by the Building Standards Act can be reliably met, while increasing the degree of freedom in designing a spiral staircase and further reducing the construction burden at the construction site. [Brief explanation of the drawings]

[0020] [Figure 1] Fig. 1(A) is a schematic perspective view of a spiral staircase according to one embodiment of the present invention, and Fig. 1(B) is a vertical cross-sectional view showing a part of the configuration of the spiral staircase. [Figure 2] FIG. 2 is a plan view of a first example of a spiral staircase in which the ascending and descending direction is a 90-degree bent staircase around the pillar. [Figure 3] FIG. 3 is a schematic diagram showing the main parts of the spiral staircase configuration example 1. [Figure 4] FIG. 4 is a flowchart illustrating an example of a method for designing a spiral staircase. [Figure 5] FIG. 5 is a provisional allocation diagram. [Figure 6] FIG. 6 is a schematic diagram of a second example of a spiral staircase. [Figure 7] FIG. 7 is a schematic diagram of a third example of a spiral staircase. [Figure 8] FIG. 8 is a schematic diagram of a fourth example of a spiral staircase. [Figure 9] FIG. 9 is a plan view of a fifth example of a spiral staircase in which the ascending and descending direction turns back at approximately 180 degrees around the pillar. [Figure 10] FIG. 10 is a schematic diagram showing the main parts of a fifth example of a spiral staircase. [Figure 11] FIG. 11 is a provisional allocation diagram in the configuration example 5. [Figure 12] FIG. 12 is a schematic diagram of a sixth example of a spiral staircase. [Figure 13]FIG. 13 is a schematic diagram of a seventh example of a spiral staircase. [Figure 14] FIG. 14 is a schematic diagram of a spiral staircase configuration example 8. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0022] <Outline of spiral staircase> Figure 1(A) is a schematic perspective view of a spiral staircase according to one embodiment of the present invention. Figure 1(B) is a vertical cross-sectional view showing part of the configuration of spiral staircase 1. As shown in Figures 1(A) and 1(B), spiral staircase 1 is a staircase that includes a section where the ascending and descending direction is not straight. Staircases where the ascending and descending direction turns at 90 degrees are called spring-folded stairs, and stairs where the ascending and descending direction turns back at 180 degrees are called turning stairs. Figure 1(A) shows a spring-folded staircase as an example.

[0023] The spiral staircase 1 is connected to, for example, straight staircases 2 and 3 that ascend and descend in a straight direction, and together with the straight staircases 2 and 3 arranged at one end and the other end of the spiral staircase 1, a staircase is formed.

[0024] The spiral staircase 1 is arranged around a column 4 whose cross section is rectangular and which extends in the vertical direction, and is arranged between an inner wall material 5 arranged along and around the column 4 and an outer wall material 6.

[0025] The spiral staircase 1 has risers 7 and treads 10 arranged alternately around the pillars 4 in the ascending and descending direction. Side panels (not shown) are attached to each of the wall materials 5 and 6, and the risers 7 and treads 10 are arranged between these side panels. The risers 7, treads 10, and side panels are sometimes sold individually as a complete assembly kit.

[0026] As clearly shown in Figure 1(B), the treads 10 are arranged horizontally, and the risers 7 are arranged vertically. The number of treads 10 is the number of steps in the spiral staircase 1. For the tread 10 directly above the riser 7, the part that protrudes horizontally from the riser 7a (front surface) of the riser 7 is the nosing 8. The amount that the nosing 8 protrudes from the riser 7a is the nosing protrusion. In plan view, the area on the top surface of the tread 10 from the end side surface 8a of the nosing 8 around the column 4 to the end side surface 8a of the nosing 8 of the adjacent tread 10 is the tread surface 20. In plan view, the distance from the end side surface 8a of the nosing 8 of one tread 10 to the end side surface 8a of the nosing 8 of the adjacent tread 10 is the tread length L20.

[0027] The wall material 5 is arranged on the inside of the curve of the spiral staircase 1. The wall material 5 has a portion 5a that is aligned with one side of the pillar 4 and portions 5b and 5c that are aligned with a pair of opposing side surfaces of the pillar 4, and these portions 5b and 5c extend in a direction away from the spiral staircase 1.

[0028] In plan view, the spiral staircase 1 is a spiral staircase in which the center 4a of the pillar 4 is set as a virtual origin O, and virtual X-axis and Y-axis that pass through the origin O and are perpendicular to each other are set as two virtual axes.

[0029] <Configuration of a folding staircase with an approximately 90-degree angle around the pillar> <Configuration example 1> Figure 2 is a plan view of a first configuration example of a spiral staircase 1, which is a folding staircase with an ascending and descending direction of approximately 90 degrees around the pillar. Figure 3 is a schematic diagram showing the main parts of the first configuration example of a spiral staircase 1. The spiral staircase 1 shown in Figures 2 and 3 is arranged at an angle of 90 degrees or within a range of approximately 90 degrees around the center of the pillar 4. In this specification, when explanations are given using plan views, the explanations will be based on the state seen from above unless otherwise specified.

[0030] As shown in Figures 1(A), 2, and 3, spiral staircase 1 has four steps, with four treads 10 (11-14) arranged around pillar 4. In this specification, multiple treads are collectively referred to as tread 10, and the nth step (n is an integer) is referred to as tread 1n. In configuration example 1, spiral staircase 1 is a staircase that progresses upward as it moves to the right. Wall thickness W is the length of one side of pillar 4 plus twice the thickness of wall material 5. If the length of one side of pillar 4 is 105 mm and the thickness of wall material 5 is 12.5 mm, wall thickness W is 105 + (12.5 x 2) = 130 mm.

[0031] In a plan view, the center 4a of the column 4 is defined as a virtual origin O, and two virtual axes are defined as virtual X- and Y-axes that pass through the origin O and are perpendicular to each other. A plurality of virtual lines 30 (31-35) are set around the center 4a. In this specification, the plurality of virtual lines are collectively referred to as virtual line 30, and the nth virtual line (n is an integer) is referred to as virtual line 3n. Since this embodiment uses a center-mounted nosing, the end side surface 8a of the nosing 8 of the tread 10 is positioned on the virtual lines 31-35. The tread surface 20 of the tread 10 (the angle range θ of the tread surface 20) is defined by the two adjacent virtual lines 30, 30. The tread surface 20 is defined by the two virtual lines 30, 30 (end side surfaces 8a, 8a), the inner wall material 5, and the outer wall material 6. In this specification, multiple treads are collectively referred to as tread 20, and the tread of the nth step (n is an integer) tread 1n is referred to as tread 2n. The actual extent of each tread 10 around the center 4a is such that one end is the end side surface 8a and the other end is the riser 7a. Therefore, tread 20 is a part of the top surface of tread 10.

[0032] In the spiral staircase 1, the treads 21, 24 (tread 21 of tread 11 in configuration 1) on the first or last step 11, 14 are the treads to be adjusted in position, so that the treads 22, 23, 24 on the steps other than those on the other steps can be designed and constructed with less effort.

[0033] Specifically, the imaginary line 31, which is one of the imaginary lines 31, 32 that define the tread surface 21 of the first step 11, does not pass through the center 4a of the pillar 4. By ensuring that the imaginary line 31 does not pass through the center 4a in this way, the tread surface 21 of the first step can be used as an adjustment surface when designing the tread surfaces 22 to 24 of the other steps.

[0034] It is preferable that the imaginary line 31, which does not pass through the center 4a of the column 4, be arranged parallel to the X-axis, as this allows the nosing 8 of the tread 11 at the end of the spiral staircase 1 to be oriented more naturally relative to the wall members 5 and 6. The imaginary line 31 may also be inclined relative to the X-axis.

[0035] For the imaginary line 31 that does not pass through the center 4a of the pillar 4, the offset dimension D1 from the center 4a is preferably equal to or less than half the wall thickness W. The offset dimension D1 is the distance between the imaginary line 31 and the center 4a. For example, if the wall thickness W is 130 mm, the offset dimension D1 is preferably 65 mm or less, and if the wall thickness W is 114 mm, the offset dimension D1 is preferably 57 mm or less. An example of the offset dimension D1 is 30 mm to 50 mm. Setting the offset dimension D1 in this range can prevent problems with the connection between the spiral staircase 1 and the straight staircases 2 and 3. Specifically, because the pillar spacing in a house is fixed at a module (typically 910 mm), depending on the conditions of the straight staircases 2 and 3, the treads of the straight staircases 2 and 3 may protrude by the offset dimension. On the other hand, straight staircases 2 and 3 typically have four steps (each with a tread surface of 227.5 mm) within a 910 mm module. If the first step 11 significantly extends into the straight staircase 2, shortening the tread surface of only the last step of the straight staircase 2 would adversely affect the design and could prevent the 150 mm tread length from being achieved. Furthermore, shortening the tread surfaces of each step of the straight staircase 2 by the amount of the first step 11 extending outward would require the straight staircase 2 to be custom-designed, increasing the manufacturing cost. Furthermore, if the offset dimension D1 becomes too large, it may become impossible to secure the brackets for the step 11 to the columns 4. For example, if the step angle range is fixed, as in the configuration described in Patent Document 1, the offset dimension cannot be adjusted, so the step may fall outside the range supported by the brackets, potentially resulting in the brackets being unable to support the step. Setting the upper limit of the offset dimension D1 as described above can mitigate these problems.

[0036] Of the multiple imaginary lines 31-35, imaginary lines 32-34, which are located midway around the center 4a, pass through the center of the column 4. The imaginary lines 31 and 32 define the tread surface 21 of the first tread 11 around the column 4. The imaginary lines 32 and 33 define the tread surface 22 of the second tread 12 around the column 4. The imaginary lines 33 and 34 define the tread surface 23 of the third tread 13 around the column 4. The imaginary lines 34 and 35 define the tread surface 24 of the fourth (final) tread 14 around the column 4. One of the multiple imaginary lines 30 is positioned on an imaginary axis, and in this embodiment, the imaginary line 35 that defines the tread surface 24 of the final (fourth) tread 14 is positioned on the Y-axis. The imaginary line 35 is also the line on which the end side surface 8a of the nosing 8 of the straight staircase 3 is located.

[0037] Furthermore, the angular range θ (θ1 to θ4) of the tread surfaces 21 to 24 of each of the treads 11 to 14 around the center 4a of the pillar 4 is not constant. In this specification, when multiple angular ranges are collectively referred to, it is referred to as the angular range θ, and when referring to the nth angular range (n is an integer), it is referred to as the angular range θn. As will be described later, the tread surface 20 of each of the treads 10 has a tread length L20 that is close to but not less than 150 mm, and the angular range θ of the tread surface 20 of each of the treads 10 is set to a convenient value that is easy to manufacture. As a result, the angular range θ (θ1 to θ4) of the tread surfaces 21 to 24 of each of the treads 11 to 14 around the center 4a of the pillar 4 is not constant.

[0038] The angle ranges θ1 to θ4 of the treads 21 to 24 are largest for the step 14 having the tread 34 defined by the imaginary line 35 arranged on the imaginary axis, and may decrease stepwise or continuously for the step 10 farthest from the step 14 having the tread 24 with the largest angle range θ. This configuration allows the angle range θ of the tread surface 20 of the step 10 to be regularized, preventing a loss of design aesthetics due to random tread lengths L20 among the step 10, and preventing the design aesthetics of the spiral staircase 1 from being impaired.

[0039] In this embodiment, the angle ranges θ1 to θ4 of the tread surfaces 21 to 24 are largest for the fourth step 14, whose tread surface 24 is defined by an imaginary line 35 positioned on the Y-axis, and decrease stepwise or continuously for steps 10 farther from the fourth step 10. The angle range θ4 for the fourth step 14 is, for example, 24.0 degrees, the angle ranges θ2 and θ3 for the second and third step 13, 12 are, for example, 23.0 degrees, and the angle range θ1 for the first step 11 is, for example, 20.0 degrees. The angle range θ may be set in units of 1 degree or 0.5 degrees, as in this embodiment, or preferably in units that facilitate cutting of the steps 10.

[0040] As a result of the angle range θ being set in units that are easy to separate, the tread lengths L21-14 of each tread 10 are not integer values. In configuration example 1, the tread lengths L21, L22, L24, and L24 of the treads 11, 12, 13, and 14 are 157.31 mm, 152.36 mm, 152.52 mm, and 153.17 mm, respectively. However, because the angle range θ is set in units that are easy to separate, cutting of each of the treads 11-14 can be easily performed.

[0041] As explained above, imaginary line 35, one of imaginary lines 31-35, is positioned on the Y-axis, and imaginary lines 32-34, which are positioned midway between imaginary lines 31-35, pass through the center of column 4. The angular ranges θ1-θ4 of each tread 21-24 around center 4a are not constant, and imaginary line 31, which defines tread 21 of first tread 11, does not pass through center 4a of column 4. This configuration allows imaginary lines 31-35 to be set based on the easy-to-understand imaginary line, imaginary line 35 on the imaginary axis, while still meeting the legal tread dimensions (150 mm or more) set forth in the Building Standards Act, even in residential structures with small column dimensions, wall thickness, and floor area. Moreover, imaginary line 31, which does not pass through center 4a of column 4, allows more room for adjusting the positions of imaginary lines 32-34, increasing the degree of freedom in designing spiral staircase 1. Furthermore, the end side surfaces 8a of the nosings 8 of the treads 12-14 are positioned on the imaginary lines 32-35 that pass through the centers 4a of the columns 4, making it easier to understand the layout of the treads 12-14 at the construction site. This makes it easier to perform construction based on the columns 4, further reducing the construction burden.

[0042] <How to design a spiral staircase> Next, an example of a design method for a spiral staircase 1 will be explained. Figure 4 is a flowchart for explaining an example of a design method for a spiral staircase 1. When explaining with reference to the flowchart, other figures will also be referenced as appropriate. A spiral staircase is designed, for example, using a computer. A designer designs the spiral staircase 1 by calculations and drawings using a computer.

[0043] When designing the spiral staircase 1, first, a coordinate system is set in plan view with the center 4a of the pillar 4 as a virtual origin O, and two virtual axes, an X axis and a Y axis that pass through the origin O and are perpendicular to each other, (step S1). Next, the directions in which to ascend and descend on the spiral staircase 1 and in which to turn are set (step S2). In the case of configuration example 1, it is set that, in plan view, going clockwise will lead to climbing toward the upper floor and then turning 90 degrees around the pillar 4.

[0044] Next, the dimensions of the pillar 4 and the thickness of the wall materials 5 and 6 to be placed around the pillar 4 are set (step S3). This step S3 corresponds to step 1) of the present invention. In the case of configuration example 1, for example, the pillar 4 is set to have a side length of 105 mm, the wall materials 5 and 6 are set to have a thickness of 12.5 mm, and the wall thickness W is set to 105 + (12.5 × 2) = 130 mm.

[0045] Next, a virtual line 30 (a reference virtual line) arranged on the virtual axis is set (step S4). In the case of configuration example 1, the virtual line 30 arranged on the virtual axis is a virtual line 35 arranged on the Y axis.

[0046] Next, the tread length L20' of the tread surface 20 of each tread 10 at a position 300 mm away from the wall surface of the inner wall material 6 is provisionally set (Step S5). In the case of Configuration Example 1, the tread length L20' is set to 150 mm. Note that the tread length L20' may be 150 mm or more, and is preferably set to a value slightly larger than 150 mm (for example, 152 mm) to allow for some leeway. Step S5 is an example of step 2) of the present invention.

[0047] Next, a provisional layout diagram for each tread 10 is created based on the conditions set in steps S1 to S4 (step S6). Step S6 is an example of step 3) of the present invention. FIG. 5 shows the provisional layout diagram. As shown in FIG. 5, the provisional layout diagram includes a column 4 and wall materials 5 and 6, and treads 21' to 24' are defined by imaginary lines 31' to 35'. Imaginary line 35' is positioned on the Y-axis. Imaginary lines 34', 33', and 32' are positioned in order from imaginary line 35'. Imaginary lines 34', 33', and 32' are positioned so that they pass through the center 4a of the column 4 and so that tread lengths L24', L23', and L22' are 150 mm. Imaginary line 31' does not pass through the center 4a of the column 4 and is positioned so that the tread length L21' of tread 11' is 150 mm. With this design, the tread lengths L21'-L24' of the tread surfaces 21'-24' of each tread board 11'-14' are set to 150 mm, and the angle range θ1'-θ4' of the tread surfaces 21'-24' is determined. After the tread surfaces 21'-24' are defined by the imaginary lines 32'-35', the imaginary line 31' is shifted from the center 4a of the column 4 by an eventual shift dimension D1' to ensure the tread length L21' of the tread surface 21' of the tread board 11'. At this point, the tread lengths L21'-L24' of each tread board 11'-14' are constant, but the angle range θ1'-θ4' varies.

[0048] Next, the angle ranges θ1' to θ4' of the treads 11' to 14' in the provisional layout are reset (Step S7). This Step S7 is an example of Step 4) of the present invention. When designing the spiral staircase 1 of Configuration Example 1, the non-integer angle range θ1' to θ4' shown in FIG. 5 is rounded to integers to become the angle range θ1 to θ4 shown in FIG. 2. As an example, the angle ranges θ2 to θ4 other than the angle range θ1 of the first tread 11 are each set to values ​​obtained by rounding off the angle range θ2' to θ4' in the provisional layout. In addition, the angle range θ1 of the tread surface 21 of the first tread 11 is set so that the sum of the angle ranges θ1 to θ4 of the tread surfaces 21 to 24 is 90 degrees. As a result, the angle range θ1 to θ4 of the treads 21 to 24 has a minimum unit of 1 degree, and is, for example, 20 degrees, 23 degrees, 23 degrees, and 24 degrees, for a total of 90 degrees.

[0049] The angle ranges θ1' to θ4' of all treads 21' to 24' in the provisional layout diagram may be rounded off or rounded up to the nearest integer. However, in this case, the sum of the angle ranges θ1 to θ4 of the treads 21 to 24 will exceed 90 degrees, which will affect the design of the straight staircase 2 on the tread 11 side. Therefore, it is preferable that the sum of the angle ranges θ1 to θ4 be 90 degrees. There are various possible methods for resetting the angle ranges θ1 to θ4 of the treads 21 to 24, such as rounding up and down the angle ranges θ4, θ3, and θ2 alternately, and finally adjusting them to the angle range θ1 of the first tread 21.

[0050] Furthermore, if the minimum unit of the angle range θ1 to θ4 is 0.5 degrees, the angle range θ2 to θ4 may be rounded up or down to the nearest value in increments of 0.5 degrees, and the first-stage angle range θ1 may be adjusted so that the sum of the angle ranges θ1 to θ4 is 90 degrees.

[0051] Next, the tread lengths L21 to L24 of the treads 11 to 14 are recalculated within the re-set angle ranges θ1 to θ4 of the treads 11 to 14 (step S8). This step S8 is an example of step 5) of the present invention. The recalculated tread lengths become the final tread lengths L22, L23, and L24 of Configuration Example 1. The tread length L21 is adjusted in the next step.

[0052] The tread length L21 determines the position of the end side surface 8a of the nosing 8 of the first tread 11, and the offset dimension D1 from the center 4a of the column 4 is adjusted (step S9). This step is an example of step 7) of the present invention. At this time, it is preferable to set the offset dimension D1 to a convenient numerical value (for example, in 1 mm increments) while ensuring that the tread length L21 of the tread 11 is 150 mm or more. This allows the offset dimension D1 to be set so that the tread 11 is positioned so that it can easily be connected to the straight staircase 2.

[0053] Next, a layout plan for each of the treads 11-14 is created based on the conditions set in steps S7-S9 (step S10). This step is an example of step 6) of the present invention. This layout plan is the official layout plan for the treads 11-14. Based on this layout plan, the material is cut and processed to manufacture the treads 11-14.

[0054] The design method described above ensures that the tread lengths L21-L24 of each tread 11-14 are at least 150 mm, while the angle range θ1-θ4 of each tread 21-24 can be set to convenient values ​​that facilitate manufacturing. Furthermore, even in residential structures with small column dimensions, wall thickness, and floor area, the legal tread dimensions (150 mm or more) stipulated by the Building Standards Act can be reliably met. Furthermore, the imaginary line 31, which does not pass through the center 4a of the column 4, allows for more room for adjustment of the position of the imaginary lines 32-34, increasing the design flexibility of the spiral staircase. Furthermore, because the end side surfaces 8a of the nosings 8 of the treads 12-14 pass along the imaginary lines 32-35, which are imaginary lines that pass through the center 4a of the column 4, the installer can easily understand the layout of the treads 12-14. This facilitates the installation of the treads 12-14 based on the column 4, thereby reducing the construction burden.

[0055] The above describes an embodiment of the present invention. However, the present invention is not limited to the above embodiment. Various modifications of the present invention are possible within the scope of the claims. Below, configurations that differ from the above embodiment will be mainly described, and similar configurations will be assigned similar reference numerals and detailed description will be omitted.

[0056] <Configuration example 2> Figure 6 is a schematic diagram of a configuration example 2 of a spiral staircase 1. The spiral staircase 1 of configuration example 2 shown in Figure 6 differs from the spiral staircase 1 of configuration example 1 in that the tread 11 of the first step of the spiral staircase 1 is positioned closer to the Y-axis of the X-axis and Y-axis, that among multiple virtual lines 31 to 35, virtual line 31 is positioned on the Y-axis, which is also a virtual axis, and that virtual line 35 does not pass through the center 4a of the column 4. The schematic diagram of configuration example 2 corresponds to the schematic diagram of configuration example 1 (Figure 3) arranged symmetrically about the Y-axis.

[0057] In configuration example 2, the imaginary line 31 that defines the tread surface 21 of the first tread 11 is positioned on the imaginary Y axis. Also, the imaginary line 35 that defines the tread surface 24 of the final (fourth) tread 14 does not pass through the center 4a of the pillar 4.

[0058] When designing the spiral staircase 1 of Configuration Example 2, the tread surface 21 of the first tread 11 is defined by imaginary lines 31 and 32 passing through the center 4a of the pillar 4, and the tread surface 24 of the fourth tread 14 is defined by an imaginary line 34 passing through the center 4a of the pillar 4 and an imaginary line 35 that does not pass through the center 4a. In Configuration Example 1, the position of imaginary line 31 was set using a shift dimension D1 in accordance with the setting of imaginary lines 32 to 35, whereas in Configuration Example 2, the position of imaginary line 35 is set using a shift dimension D4' in accordance with the setting of imaginary lines 31 to 34. Then, the shift dimension D4 is adjusted (step S9).

[0059] In configuration example 2, the virtual line placed on the virtual axis (the reference virtual line) is virtual line 31 placed on the Y-axis. Also, when designing spiral staircase 1 in configuration example 2, in step S6, after treads 21'-23' are partitioned by virtual lines 31'-34', virtual line 35' is shifted from center 4a of column 4 by eventual shift dimension D4' to ensure tread length L24' of tread 24' of tread board 14'.

[0060] <Configuration example 3> Figure 7 is a schematic diagram of Configuration Example 3 of a spiral staircase 1. The spiral staircase 1 of Configuration Example 3 shown in Figure 7 differs from the spiral staircase 1 of Configuration Example 2 in the ascending direction in plan view. In Configuration Example 2, the ascending direction of the stairs is clockwise in plan view, whereas in Configuration Example 3, the ascending direction of the stairs is counterclockwise in plan view. Other than this, Configuration Examples 2 and 3 have the same configuration and are designed in the same way.

[0061] <Configuration Example 4> Figure 8 is a schematic diagram of configuration example 4 of a spiral staircase 1. The spiral staircase 1 of configuration example 4 shown in Figure 8 differs from the spiral staircase 1 of configuration example 1 in the ascending direction in plan view. In configuration example 1, the ascending direction of the stairs is clockwise in plan view, whereas in configuration example 4, the ascending direction of the stairs is counterclockwise in plan view. Furthermore, the schematic diagram of configuration example 4 corresponds to the schematic diagram of configuration example 1 (Figure 3) arranged symmetrically about the Y axis. Other than this, configuration examples 1 and 4 have the same configuration and are designed in the same way.

[0062] The above is an example of a folding staircase with a 90-degree angle around the pillar. Next, we will explain the configuration of a folding staircase with a 180-degree angle around the pillar.

[0063] <The staircase has a 180-degree turn around the pillar in the ascending and descending direction> <Configuration example 5> Figure 9 is a plan view of Configuration Example 5 of a spiral staircase 1, in which the ascending and descending direction is a staircase that turns around 180 degrees or approximately 180 degrees around the pillar. Figure 10 is a schematic diagram showing the main parts of Configuration Example 5 of a spiral staircase 1. The spiral staircase 1 of Configuration Example 5 shown in Figures 9 and 10 is arranged in a range of approximately 180 degrees around the center of the pillar 4. The spiral staircase 1 of Configuration Example 5 has eight steps, with eight treads 11 to 18 arranged around the pillar 4. The spiral staircase 1 of Configuration Example 5 is a staircase that progresses upward as you go from left to right.

[0064] In plan view, multiple imaginary lines 31-39 are set around the center 4a. Two adjacent imaginary lines 30, 30 define the tread surfaces 21-28 of the treads 11-18. The imaginary lines 31-35 have the same configuration as in Configuration Example 1. In Configuration Example 5, the configuration of Configuration Example 1 is supplemented by the addition of treads 15-18 having tread surfaces 25-28 defined by imaginary lines 35-39.

[0065] In the spiral staircase 1, the positions of the treads 21, 28 on at least one of the treads 11, 18 on the first and last steps (in configuration example 5, both) are set as the treads to be adjusted, thereby reducing the effort required for designing and constructing the treads 22-27 on the treads 12-17 on steps other than those on the other steps.

[0066] Specifically, the imaginary line 31, which is one of the imaginary lines 31, 32 that define the tread surface 21 of the first tread 11, does not pass through the center 4a of the column 4. By ensuring that the imaginary line 31 does not pass through the center 4a, the tread surface 21 of the first tread 11 can be used as an adjustment surface during the design of the treads 22-27 of the other steps (especially treads 22-24). Furthermore, the imaginary line 39, which is one of the imaginary lines 38, 39 that define the tread surface 28 of the final step (eighth step), does not pass through the center 4a of the column 4. The imaginary line 39 is also the line on which the end side surface 8a of the nosing 8 of the straight staircase 3 is located. By ensuring that the imaginary line 39 does not pass through the center 4a, the tread surface 28 of the eighth tread 18 can be used as an adjustment surface during the design of the treads 22-27 of the other steps (especially treads 25-27). As described above, in the fifth configuration example, the imaginary lines 31 and 39 that define the tread surfaces 21 and 28 of the last and first step treads 11 and 18 do not pass through the center 4a of the pillar 4.

[0067] It is preferable that the imaginary lines 31 and 39, which do not pass through the center 4a of the column 4, be arranged parallel to the X-axis, as this allows the nosing at the end of the spiral staircase 1 to face the wall members 5 and 6 in a more natural direction. Note that the imaginary lines 31 and 39 may be inclined with respect to the X-axis.

[0068] For at least one of the imaginary lines 31, 39 that do not pass through the center 4a of the column 4, the offset D1, D8 from the center 4a is preferably equal to or less than half the wall thickness W. Setting these offsets D1, D8 minimizes the need for a proper fit between the spiral staircase 1 and the straight staircases 2, 3. Specifically, because the spacing between columns in a house is fixed (typically 910 mm), the steps of the straight staircases 2, 3 may extend beyond the offset by the offset, depending on the conditions of the straight staircases 2, 3. Meanwhile, the straight staircases 2, 3 typically have four steps (each with a tread of 227.5 mm) within a 910 mm module. If the first or eighth step 10 extends significantly beyond the straight staircases 2, 3, shortening the tread of the last step on the spiral staircase side on the straight staircase 2, 3 side can adversely affect the design and may prevent the required 150 mm tread length from being achieved. Furthermore, if the tread surfaces of the straight staircases 2 and 3 were shortened and divided evenly to account for the protrusion of the first or eighth step 11 or 18, the straight staircase would have to be custom-designed, increasing the manufacturing costs. Furthermore, if the offset dimensions D1 and D8 were too large, the brackets for the steps 11 and 18 might not be able to be secured to the columns 4. For example, as in the configuration described in Patent Document 1, if the step angle range is fixed, the offset dimension cannot be adjusted, so the brackets might fall outside the range that can be supported by the brackets, potentially making it impossible for the step to be supported by the brackets. Setting the upper limits of the offset dimensions D1 and D8 as described above can mitigate these problems.

[0069] It is preferable that the shift dimension D1 of the imaginary line 31 and the shift dimension D8 of the imaginary line 39 are the same, in order to prevent the shift dimension value from being biased towards either the tread 11 or 18.

[0070] Of the multiple imaginary lines 31-39, imaginary lines 32-38, which are located in the middle around the center 4a, pass through the center of the pillar 4. Imaginary lines 35 and 36 define the tread surface 25 of the fifth step 15 around the pillar 4. Imaginary lines 36 and 37 define the tread surface 26 of the sixth step 16 around the pillar 4. Imaginary lines 37 and 38 define the tread surface 27 of the seventh step 17 around the pillar 4. Imaginary lines 38 and 39 define the tread surface 28 of the eighth (final) step 18 around the pillar 4. One of the multiple imaginary lines 31-39 is located on an imaginary axis, and in this embodiment, imaginary line 35, which is located on the Y-axis, defines the tread surfaces 24 and 25 of the two steps 14 and 15 in the middle around the center 4a.

[0071] Furthermore, the angle range θ (θ1 to θ8) of the tread surfaces 21 to 28 of each of the treads 11 to 18 around the center 4a of the pillar 4 is not constant. As will be described later, the tread surfaces 21 to 28 of each of the treads 11 to 16 have tread lengths L21 to L28 that are close to but not less than 150 mm, while the angle range θ1 to θ8 of the treads 11 to 18 are set to simple values ​​that are easy to manufacture. As a result, the angle range θ1 to θ8 of the tread surfaces 21 to 28 of each of the treads 11 to 18 around the center 4a of the pillar 4 is not constant.

[0072] The angle range θ1 to θ8 of each of the treads 21 to 28 may be largest for the step 14, 15 having the tread 24, 25 defined by the imaginary line 35 arranged on the imaginary axis (Y-axis), and may decrease stepwise or continuously for the step 10 farthest from the step 14, 15 having the tread 24, 25 with the largest angle range θ. This configuration imparts regularity to the angle range θ of the treads 21 to 28 of the treads 11 to 18, suppressing a loss of design aesthetics due to random tread lengths L21 to L28, and preventing the design aesthetics of the spiral staircase 1 from being impaired.

[0073] In this embodiment, the angle ranges θ1 to θ8 of the treads 21 to 28 are largest for the fourth and fifth steps 14, 15, which have treads 24, 25 defined by a virtual line 35 positioned on the Y axis, and decrease stepwise or continuously for steps 10 farther from the fourth and fifth steps 14, 15. The angle range θ for the fourth and fifth steps 14, 15 is, for example, 24.0 degrees, the angle ranges θ2, θ3, θ6, θ7 for the second, third, sixth, and seventh steps 12, 13, 16, 17 are, for example, 23.0 degrees, and the angle ranges θ1, θ8 for the first and eighth steps 11, 18 are, for example, 20.0 degrees. In configuration example 5, the angle ranges θ1 to θ8 of the treads 21 to 28 are set symmetrically about the Y axis. The minimum unit of the angle range θ1 to θ8 may be 1 degree as in this embodiment, or may be 0.5 degrees. The minimum unit of the angle range θ1 to θ8 is preferably set to a unit that makes it easy to cut the treads 11 to 18.

[0074] As a result of the angle range θ1 to θ8 being set in easily divisible units, the tread lengths L21 to L28 of each tread 11 to 18 are not integer values. In configuration example 5, the tread lengths L21, L22, L23, and L24 of treads 11, 12, 13, and 14 are 157.31 mm, 152.36 mm, 152.52 mm, and 153.17 mm, respectively. Furthermore, the tread lengths L28, L27, L26, and L25 of treads 18, 17, 16, and 15, which are symmetrical to treads 11, 12, 13, and 14 about the Y axis, are 157.31 mm, 152.36 mm, 152.52 mm, and 153.17 mm, respectively. However, because the angle range θ1 to θ8 is set in easily divisible units, cutting of treads 11 to 18 can be easily performed.

[0075] As explained above, imaginary line 35, one of imaginary lines 31-39, is positioned on the Y-axis, and imaginary lines 32-38, which are positioned midway between imaginary lines 31-39, pass through the center of column 4. Furthermore, the angular ranges θ1-θ8 of the treads 21-28 around center 4a are not constant, and imaginary lines 31, 39, which separate the treads 21, 28 of the first and eighth treads 11, 18, do not pass through center 4a of column 4. This configuration allows imaginary lines 31-39 to be set based on the easily understandable imaginary line 35 on the imaginary axis, while still meeting the legal tread dimensions (150 mm or more) set forth in the Building Standards Act, even in residential structures with small column dimensions, wall thicknesses, and floor areas. Furthermore, imaginary lines 31, 39, which do not pass through center 4a of column 4, allow for more room for adjusting the positions of imaginary lines 32-38, increasing the degree of freedom in designing spiral staircases. Furthermore, because the end side surfaces 8a of the nosings 8 of the treads 12-17 pass along imaginary lines 32-38 passing through the center 4a of the column 4, the layout of the treads 12-17 is easy to understand at the construction site. This makes it easier to install the treads based on the column 4, reducing the construction burden. Furthermore, after adjusting the angle ranges θ2-θ7 of the treads 22-27, the angle ranges θ1-θ8 of the treads 21-28 can be adjusted using the two imaginary lines 31-39 on both treads 11-18. This prevents either tread 11-18 from being significantly misaligned with the X-axis, minimizing the adjustment required for the tread length of the straight staircases 2-3 connected to the spiral staircase 1. This reduces the effort required for designing and installing the straight staircases 2-3.

[0076] <How to design a spiral staircase> Next, an example of a design method for the spiral staircase 1 of Configuration Example 5 will be described. Differences from the design method for the spiral staircase 1 of Configuration Example 1 will be mainly described with reference to Fig. 4 .

[0077] In the case of configuration example 5, the direction of ascending and descending and the direction of turning on the spiral staircase 1 are set in the design (step S2). In the case of configuration example 5, it is set that, in plan view, going clockwise will lead to climbing towards the upper floor and turning 180 degrees around pillar 4.

[0078] In the case of configuration example 5, when a virtual line (a reference virtual line) to be placed on the virtual axis is set (step S4), the virtual line to be placed on the virtual axis is virtual line 35 placed on the Y axis.

[0079] In the case of configuration example 5, in the provisional setting (step S5) of the tread surface lengths L21' to L28' of the treads 11' to 18', the tread surface lengths L21' to L28' are set to, for example, 150 mm.

[0080] In the case of Configuration Example 5, a temporary layout diagram for each tread 11'-18' is created (step S6), resulting in the temporary layout diagram shown in FIG. 11. FIG. 11 is a temporary layout diagram for Configuration Example 5. As shown in FIG. 11, in the temporary layout diagram, a column 4 and wall materials 5 and 6 are created, and treads 21'-28' are defined by virtual lines 31'-39'. Virtual line 35' is positioned on the Y axis, and virtual lines 34', 33', 32', and virtual lines 36', 37', and 38' are positioned in order from virtual line 35' so that they pass through the center 4a of the column 4 and so that tread lengths L22'-L27' are 150 mm. Virtual lines 31' and 39' do not pass through the center 4a of the column 4 and so that tread lengths L21' and L28' of treads 11' and 18' are 150 mm. With this design, the tread lengths L21'-L28' of the tread surfaces 21'-28' of each tread board 21'-28' are set to 150 mm, and the angle range θ1'-θ8' is determined. After the tread surfaces L21'-L28' are defined by the imaginary lines 32'-38', the imaginary lines 31', 39' are shifted from the center 4a of the column 4 by the eventual shift dimensions D1', D8' to ensure the tread lengths L21', L28' of the tread surfaces 21', 28' of the tread boards 11, 18. At this point, the tread lengths L21'-L28' of each tread board 11'-18' are constant, and the angle ranges θ1'-θ8' are variable.

[0081] In Configuration Example 5, the angle ranges θ1' to θ8' of each step 11' to 18' in the provisional layout diagram are reset (Step S7) to integers. As an example, the angle ranges θ2 to θ7 other than the angle ranges θ1 and θ8 of the first and eighth step 11, 18 shown in FIG. 9 are set to values ​​obtained by rounding off the angle ranges θ2' to θ7' in the provisional layout diagram shown in FIG. 11. Furthermore, the angle ranges θ1 and θ8 of the first and eighth step 11, 18 shown in FIG. 9 are set so that the sum of the angle ranges θ1 to θ8 of the tread surfaces 21 to 28 is 180 degrees. As a result, in Configuration Example 5, for example, the angle ranges θ1 to θ8 of the tread surfaces 21 to 28 are 20 degrees, 23 degrees, 23 degrees, 24 degrees, 24 degrees, 23 degrees, 23 degrees, and 20 degrees, totaling 180 degrees. In addition, in the case of configuration example 5, the angle range θ1 to θ8 can be adjusted for either the tread surfaces 21, 28 of the treads 11, 18 of the first or final step, and the angle range θ22 to θ27 of the tread surfaces 22 to 27 of the treads 12 to 17 of the other steps can be rounded up or down so that the total of the angle ranges θ1 to θ8 becomes 180 degrees.

[0082] The angle ranges θ1' to θ8' of all treads 21' to 28' in the provisional layout diagram may be rounded up or down to the nearest integer. However, in this case, the sum of the angle ranges θ1 to θ8 of treads 21 to 28 exceeds 180 degrees, which would affect the design of the straight staircases 2 and 3 on the tread 11 and tread 18 sides. Therefore, it is preferable that the sum of the angle ranges θ1 to θ8 be 180 degrees. Various methods can be considered for resetting the angle ranges θ1 to θ8 of the treads 21 to 28, such as rounding up and down the angle ranges θ4, θ3, θ2 and the angle ranges θ6, θ7, θ8 alternately, and finally adjusting them to the angle ranges θ1 and θ8 of the first and eighth step treads 21 and 28.

[0083] Furthermore, if the minimum unit of the angle range θ1 to θ8 is 0.5 degrees, the angle range θ2 to θ7 may be rounded up or down to the nearest value in increments of 0.5 degrees, and both the first and last step angle ranges θ1, θ8 may be adjusted so that the total of the angle ranges θ1 to θ8 becomes 180 degrees. Furthermore, if the minimum unit of the angle range θ1 to θ8 is 0.5 degrees, the angle may be adjusted in either the first or last step angle range θ1, θ8 so that the total of the angle ranges θ1 to θ8 becomes 180 degrees.

[0084] In the case of Configuration Example 5, the tread lengths L21 to L28 of the treads 11 to 18 are recalculated within the reset angle ranges θ1 to θ8 of the treads 11 to 18 (Step S8). The recalculated tread lengths become the tread lengths L22 to L27 of Configuration Example 5. Meanwhile, the tread lengths L21 and L28 are adjusted in the next step.

[0085] Specifically, offset dimensions D1 and D8 from the center 4a of the column 4 are set for the end side surfaces 8a of the nosings 8 of the first and eighth treads 11 and 18 (Step S9). It is preferable to set the offset dimensions D1 and D9 to easy-to-round values ​​(for example, in 1 mm increments) while ensuring that the tread surface lengths L21 and L28 of the treads 11 and 18 are 150 mm or more. This allows the offset amounts D1 and D8 to be set so that the treads 11 and 18 are positioned so that they can easily connect to the straight staircase.

[0086] Next, based on the conditions set in steps S7 to S9, a layout diagram for each of the treads 11 to 18 is recreated (step S9). This layout diagram is the official layout diagram for the treads 11 to 18. Based on this layout diagram, the material is cut and processed to manufacture the treads 11 to 14.

[0087] In this way, according to configuration example 5, which is a staircase with a turning angle of approximately 180 degrees, it is possible to increase the freedom of design for spiral staircases while reliably meeting the legal dimensions of the treads set forth in the Building Standards Act even in residential structures with small pillar dimensions, wall material thickness, and floor area, and further reduce the construction burden at the construction site.

[0088] <Configuration Example 6> Figure 12 is a schematic diagram of Configuration Example 6 of a spiral staircase 1. The spiral staircase 1 of Configuration Example 6 shown in Figure 12 differs from the spiral staircase 1 of Configuration Example 5 in the direction of ascent in plan view. In Configuration Example 5, the ascent direction of the stairs is clockwise in plan view, whereas in Configuration Example 5, the ascent direction of the stairs is counterclockwise in plan view. Other than this, Configuration Examples 5 and 6 have the same configuration and are designed in the same way.

[0089] <Configuration Example 7> FIG. 13 is a schematic diagram of Configuration Example 7 of a spiral staircase 1. Configuration Example 7 differs from Configuration Example 5 in the virtual line 30 arranged on the virtual axis. In Configuration Example 5, virtual line 35 was arranged on the Y axis, whereas in Configuration Example 7, virtual line 39 is arranged on the X axis. That is, virtual line 39 that defines the tread surface 28 of the tread 18 of the final step (the eighth step) is arranged on the X axis. Furthermore, in Configuration Example 7, virtual line 35 is arranged offset from the Y axis. This allows the allocation of the offset dimension D1 to be concentrated on tread 11 of treads 11, 18.

[0090] In the spiral staircase 1, the position of the tread 21 on either the first or last step tread 11, 18 (in configuration example 7, tread 11) is set as the tread to be adjusted, thereby reducing the effort required to design and construct the treads 22 to 27 on steps other than those other than those.

[0091] Specifically, the imaginary line 31, which is one of the imaginary lines 31, 32 that define the tread surface 21 of the first tread 11, does not pass through the center 4a of the pillar 4. By ensuring that the imaginary line 31 does not pass through the center 4a in this way, the tread surface 21 of the first tread 11 can be used as a surface for adjusting the design of the tread surfaces 22 to 28 of the other steps. On the other hand, the imaginary line 39, which is one of the imaginary lines 38, 39 that define the tread surface 28 of the final (eighth) step 18, is positioned on the X-axis and passes through the center 4a of the pillar 4.

[0092] Of the multiple imaginary lines 31-39, imaginary lines 32-39 other than imaginary line 31 pass through the center of the pillar 4. In addition, imaginary lines 32-37 that define the tread surfaces 22-27 of the treads 12-17 of the middle steps (second to seventh steps) are positioned offset from the imaginary axes (X-axis and Y-axis).

[0093] According to the configuration of Configuration Example 7, the offset dimension can be concentrated on tread 11 of treads 11 and 18, so the design of spiral staircase 1 does not affect the design of the treads of straight staircase 3 connected to tread 18. Therefore, the design and construction of straight staircase 3 connected to tread 18 does not require much effort.

[0094] <How to design a spiral staircase> Next, an example of a design method for the spiral staircase 1 of Configuration Example 7 will be described. Differences from the design method for the spiral staircase 1 of Configuration Example 5 will be mainly described while showing Fig. 4 .

[0095] In the case of configuration example 7, when the virtual line 30 (reference virtual line) arranged on the virtual axis is set (step S4), the virtual line 30 arranged on the virtual axis is the virtual line 39 arranged on the X-axis.

[0096] In the case of configuration example 7, in creating a temporary layout diagram for each of the treads 11'-18' (step S6), an imaginary line 39' that defines the tread surface 28' of the eighth tread 18' is placed on the X axis. Then, starting from this imaginary line 39', imaginary lines 38'-31' are placed in order so that the tread surface lengths L28'-L21' of each of the treads 18'-11' are 150 mm or more.

[0097] <Configuration Example 8> Figure 14 is a schematic diagram of Configuration Example 8 of a spiral staircase 1. The spiral staircase 1 of Configuration Example 8 shown in Figure 14 differs from the spiral staircase 1 of Configuration Example 7 in the ascending direction in plan view. In Configuration Example 7, the ascending direction of the stairs is clockwise in plan view, while in Configuration Example 8, the ascending direction of the stairs is counterclockwise in plan view. Due to this configuration, in Configuration Example 8, the imaginary line 31 is aligned on the X-axis. In other words, the imaginary line 31 that defines the tread surface 21 of the first tread 11 is aligned on the X-axis. This allows the allocation of the offset dimension D8 to be concentrated on tread 18 of the treads 11 and 18. Other than this, Configuration Examples 7 and 8 have the same configuration and are designed in the same way.

[0098] <Other configuration examples> In each of the configuration examples described above, offset dimensions D1, D8 from the center 4a of the column 4 were set for the end side surface 8a of the nosing 8 of at least one of the treads 11, 18 of the first and eighth steps (Step S9). However, this does not have to be the case. If the tread surface lengths L21, L28 of the treads 11, 18 are secured to be 150 mm or more at the time of Step S8, Step S9 may be omitted.

[0099] In addition, in the above-mentioned configuration examples, the end side surface 8a of the stair nosing 8 is positioned on the imaginary line 30 (31-39). However, this is not necessarily the case. Each tread 11-18 may be designed so that the riser 7a of the riser 7 is positioned on the imaginary line 30 (31-39). In this case, the riser 7 is installed on the imaginary line and arranged around the column 4, resulting in a riser-centered configuration. With a riser-centered configuration, the riser 7a of the riser 7 is positioned on the imaginary line 30, and the position of the nosing 8 is offset by the dimension of the nose projection (end cover). The dimension between the risers 7a is the dimension between the imaginary lines 30, 30. The angle range θ (θ1-θ8) of the tread surface 20 of the tread 10 is defined by two adjacent imaginary lines 30, 30. Even with this riser-centered configuration, each tread 11-18 can be designed in the same way as the stair nosing-centered configuration shown in Configuration Examples 1-8 above. [Example]

[0100] Using a computer, the design method described in the examples was used to design spiral staircases as Examples 1 to 4. The design conditions for Examples 1 to 4 were as follows: Example 1 90-degree 4-step spiral staircase Length of one side of pillar 4: 105 mm Wall material 6 thickness: 12.5 mm Wall thickness W: 130mm An imaginary line that does not pass through the center 4a of the pillar 4: an imaginary line 31 (the position of the tread surface 21 of the first step 11 is the object of adjustment) House structure: Traditional wooden frame structure Example 2 90-degree 4-step spiral staircase Length of one side of pillar 4: 89 mm Wall material 6 thickness: 12.5 mm Wall thickness W: 114mm An imaginary line that does not pass through the center 4a of the pillar 4: an imaginary line 31 (the position of the tread surface 21 of the first step 11 is the object of adjustment) House structure: 2x4 (two-by-four) structure Example 3 180-degree spiral staircase with 8 steps Length of one side of pillar 4: 105 mm Wall material 6 thickness: 12.5 mm Wall thickness W: 130mm Imaginary lines that do not pass through the center 4a of the pillar 4: imaginary lines 31, 39 (the positions of the treads 21, 28 of the treads 11, 18 on the first and eighth steps are subject to adjustment) House structure: Traditional wooden frame structure Example 4 180-degree spiral staircase with 8 steps Length of one side of pillar 4: 89 mm Wall material 6 thickness: 12.5 mm Wall thickness mm: 114mm Imaginary lines that do not pass through the center 4a of the pillar 4: imaginary lines 31, 39 (the positions of the treads 21, 28 of the treads 11, 18 on the first and eighth steps are subject to adjustment) House structure: 2x4 (two-by-four) structure

[0101] (Conditions common to Examples 1 to 4) Provisional setting value of tread length in step S5: 152 mm

[0102] When the design was performed under the above conditions, the angle range θ1' to θ8' of the treads 11' to 18', the tread surface lengths L21' to L28', and the offset dimensions D1', D8' of the imaginary lines 31', 39' dividing the tread surfaces 21', 28' of the first and eighth treads 11', 18' obtained in creating the provisional layout diagram (Step S6) were the values ​​shown in Table 1 for Examples 1 and 2, and the values ​​shown in Table 2 for Examples 3 and 4. Furthermore, when the angle range θ1', θ8' of each tread 11', 18' in the provisional layout diagram was reset (Step S7), the angle range θ1 to θ8 of the treads 11 to 18 was the value shown in Table 1 for Examples 1 and 2, and the value shown in Table 2 for Examples 3 and 4. As a result of this resetting, the tread lengths L21 to L28 of the treads 11 to 18 were recalculated (Step S8), resulting in the values ​​shown in Table 1 for Examples 1 and 2, and the values ​​shown in Table 2 for Examples 3 and 4. For the treads 11 and 18, the tread lengths L21 and L28 and the offset dimensions D1 and D8 recalculated in Step S8 are shown in parentheses. Next, the offset dimensions D1 and D8 from the center 4a of the column 4 were adjusted for the virtual lines 31 and 39 of the first and eighth treads 11 and 18 (Step S9). The offset dimensions D1 and D8 obtained through this adjustment and the tread lengths L21 and L28 calculated from the offset dimensions D1 and D8 were the values ​​without parentheses shown in Table 1 for Examples 1 and 2, and the values ​​without parentheses shown in Table 2 for Examples 3 and 4. Note that for the first and eighth treads 11, 18, the difference between the parenthesized and non-parenthesized values ​​for tread surfaces 21, 28 (157.308 - 149.707 = 7.601 mm) does not strictly match the difference between the parenthesized and non-parenthesized values ​​for offset dimensions D1, D8 (30 - 22.345 = 7.655 mm). This is because tread lengths L21, L28 are the lengths 300 mm from the surface of the inner wall material 5, and are not the perpendicular distances to imaginary lines 31, 39 that define the tread surfaces 21, 28 of the first and eighth treads 11, 18. [Table 1] [Table 2]

[0103] In all of Examples 1 to 4, by appropriately setting the positions (shift dimensions D1, D8) of the tread surfaces 21, 28 of the first and eighth step treads 11, 18, it was possible to design the spiral staircase 1 while ensuring a minimum tread length of 150 mm or more.

[0104] In Examples 1 and 3, when the tread lengths were recalculated in step S8, the tread lengths L21 and L28 of the treads 11 and 18 were 149.707 mm, less than 150 mm. Even in this case, by adjusting the offset dimensions D1 and D8 from 22.345 mm to 30 mm in step S9, the tread lengths L21 and L28 of the treads 11 and 18 were able to be 157.308 mm, more than 150 mm. In this way, with the simple configuration of adjusting the offset dimensions D1 and D8, the tread lengths L21 to L28 of all treads 21 to 28 were able to be 150 mm or more.

[0105] In Examples 2 and 4, when the tread lengths were recalculated in step S8, the tread lengths L21 and L28 of the treads 11 and 18 were 153.102 mm, which was greater than 150 mm. Even in this case, by adjusting the offset dimensions D1 and D8 to smaller values ​​in step S9 (from 38.052 mm to 35 mm), it was possible to shorten the offset dimensions D1 and D8 while keeping the tread lengths L21 and L28 to the minimum necessary value (150.066 mm) greater than 150 mm.

[0106] As a comparative example, when the shift dimensions D1 and D8 are both set to zero in step S9, the tread lengths L21 and L28 of the first and eighth step treads 11 and 18 are both 127.554 mm, which is less than 150 mm and does not meet the requirement of 150 mm or more as required by the Building Standards Act. [Industrial Applicability]

[0107] According to the present invention, a spiral staircase, a spiral staircase design method, and a spiral staircase manufacturing method can be provided. [Explanation of symbols]

[0108] 1 Spiral Staircase 4 pillars 4a Center of the pillar 7. Kickboard 8 Nosing 8a End side 10~18 Treadboard 20~28 treads 30~39 Virtual line D1, D8 offset dimensions L21~L28 Tread length (tread dimensions) W Column wall thickness θ,θ21~θ28 angle range

Claims

1. In a plan view, the center of the pillar is set as a virtual origin, and a virtual X-axis and a virtual Y-axis that pass through the origin and are perpendicular to each other are set as two virtual axes. a plurality of treads disposed around the pillar; When a plurality of virtual lines are set around the center in a plan view, The end side surface of the nose of the tread or the riser is disposed on the imaginary line, The two adjacent imaginary lines define an angle range of the tread surface of the tread plate, one of the plurality of virtual lines is disposed on the virtual axis; Among the plurality of virtual lines, the virtual line disposed at the middle around the center passes through the center, The angular extent of the tread surface of each of the treads about the center is not constant, A spiral staircase, characterized in that one of the imaginary lines defining the angular range of the tread surface of the first or last step does not pass through the center of the column.

2. the spiral staircase is disposed at or within about 90 degrees of the center of the column; 2. The spiral staircase according to claim 1, wherein one of the imaginary lines defining the angular range of the tread surface of the tread of the last step or the first step is disposed on the imaginary axis.

3. the spiral staircase is disposed at or about 180 degrees around the center of the column; The angular range of the tread surfaces of the two treads in the middle around the center is defined by the imaginary line disposed on the imaginary axis, 2. The spiral staircase according to claim 1, wherein one of the imaginary lines defining the angular range of the tread surface of at least one of the treads of the last step and the first step does not pass through a center of the column.

4. The spiral staircase is disposed at or about 180 degrees around the center; A spiral staircase as described in claim 1, wherein one of the virtual lines defining the angular range of the tread surface of the tread of the final step or the first step is positioned on the virtual axis, and the virtual line defining the angular range of the tread surface of the tread of the intermediate step is positioned offset from the virtual axis.

5. The spiral staircase according to claim 1 , wherein the imaginary line that does not pass through the center of the column is arranged parallel to the imaginary axis.

6. The spiral staircase according to any one of claims 1 to 5, wherein the imaginary line that does not pass through the center of the column has a shift dimension from the center that is less than or equal to 1 / 2 of the wall thickness of the column.

7. 2. The spiral staircase of claim 1, wherein the angular range of each of the tread surfaces of the step is largest for the step having the tread surface partitioned by the virtual line arranged on the virtual axis, and the angular range decreases stepwise or continuously for the step farther from the step with the largest tread surface.

8. A method for designing a spiral staircase having a plurality of treads, in which the center of the pillar is set as a virtual origin in a plan view, and virtual X-axis and Y-axis passing through the origin and perpendicular to each other are set as two virtual axes, 1) determining the dimensions of the pillar and the thickness of the wall material to be placed around the pillar; 2) determining the tread length of each of the treads at a position 300 mm away from the wall surface of the wall material; 3) creating a provisional layout diagram for each step based on the conditions input in steps 1) and 2); 4) A step of resetting the angle range of each of the tread surfaces in the provisional allocation diagram created in the step 3); 5) recalculating the tread length of each of the treads in the angle range of each of the treads reset in step 4); 6) A step of recreating an allocation diagram of each of the treads based on the conditions obtained in steps 4) and 5); A method for designing a spiral staircase.

9. The method further includes step 7) of setting a shift dimension of the first or last step from the center of the column after recalculating the step length of each step in step 5), 9. A method for designing a spiral staircase according to claim 8, wherein in said step 6), a layout diagram for each of said treads is recreated from the conditions obtained in said steps 4), 5), and 7).

10. A method for manufacturing a spiral staircase, comprising the steps of: manufacturing the treads in a shape designed by the design method according to claim 8 or 9.

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