Steel staircase treads and steel staircase

Abstract

To provide steel stair treads that are as lightweight as possible, easy to handle, and have a simple structure, as well as steel staircases that use these steel stair treads to protect recesses of each step.SOLUTION: A steel staircase tread 60 having a rise piece 12 that protrudes upward from a stair-nosing 11a of a tread 11, and used for curing recesses 14 formed by a tread 11, a kick plate 13, and the rise piece 12 during a period until a cementitious material is poured comprises: a rectangular or substantially rectangular tread piece 20 made of resin, a pair of leg pieces 30 made of resin that extend downward along a pair of long sides and / or a pair of short sides of the tread piece 20, and a pair of auxiliary leg pieces 40 made of resin that are provided between the pair of leg pieces 30 among bottom surfaces 24 of the tread piece 20.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a tread for a steel frame staircase and a steel frame staircase. [Background technology]

[0002] In the construction of buildings and other structures, steel staircases are generally used for workers to enter and exit the structure under construction and for carrying in and out construction materials and equipment. Fig. 1 shows an example of a conventional steel staircase in perspective, and Fig. 2 shows an enlarged side view of a step. The illustrated steel staircase 10 has a structure in which a plurality of steps 15 are continuously attached to a stringer 17.

[0003] A rising piece 12 that protrudes upward is provided on the nosing 11a of the tread 11 that forms each step 15, and a recess 14 is formed by the tread 11, riser 13, and rising piece 12. This recess 14 will eventually be filled with a cement-based material such as concrete or mortar and will disappear, but until then the recess 14 will exist.

[0004] Therefore, in both cases where the worker F ascends the steel staircase 10 in the X1 direction as shown in FIG. 3(a) and where the worker F descends the steel staircase 10 in the X2 direction as shown in FIG. 3(b), the worker F's feet are supported at two points by the tops of the rising pieces 12 and the treads 11, which are at different heights. In addition, the worker F's toes are likely to trip on the rising pieces 10. For these reasons, the worker F's feet are likely to become unstable when ascending or descending the steel staircase 10, which poses safety issues when ascending or descending the steel staircase 10, and taking care to ascend or descend safely can lead to excessive stress.

[0005] In addition, since the steel staircase 10 is located at a construction site, dirt such as dust, as well as mud and rainwater, tend to accumulate in the recesses 14 of each step 15. If these accumulate in the recesses, the feet become slippery, which also reduces safety when ascending and descending.

[0006] For the above reasons, what is desired is a curing material that can ensure safety when ascending and descending during the period until cement-based material is poured into the recesses 14 of the steel staircase 10, and a steel staircase that has this curing material in the recesses of each step (a temporary steel staircase).

[0007] Here, Patent Document 1 proposes a tread for steel-framed stairs. This tread for steel-framed stairs is used for steel-framed stairs in which a vertical wall leading to the next step is installed at the base end of the step and a small vertical wall lower than the vertical wall is installed at the opposite tip end. This tread has a tread body having a width smaller than the dimension between the vertical wall and the small vertical wall, and an elastic body provided on the tread body to hold the tread body between the vertical wall and the small vertical wall without rattling. More specifically, two angles of the same length are arranged in parallel with a distance L1, and both ends of these are connected with a cylinder to form a square frame, and a mesh-like tread part is fixed to the upper side by welding or the like, and the elastic body is biased by a spring means so as to protrude from the tread body. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2000-314218 A Summary of the Invention [Problem to be solved by the invention]

[0009] The steel stair tread described in Patent Document 1 is made entirely of metal, and it is clear that such a heavy metal tread would be difficult to handle when transporting and installing it in the recesses of each step of a steel staircase with many steps, and would also be difficult to handle when removing it from the recesses and carrying it out to pour the cement-based material.

[0010] In addition, since the elastic body has a complex structure in which it protrudes from the metal tread body by a spring means, there are concerns about the effort and cost involved in manufacturing, and considering the need to protect the recesses of many steps, this issue becomes more pronounced as the number of treads for steel staircases increases.

[0011] The present invention has been made in consideration of the above problems, and aims to provide a tread material for steel frame stairs that is as lightweight as possible, has excellent handling properties, and is not complicated in structure, and a steel frame staircase in which the recesses of each step are protected by this tread material for steel frame stairs. [Means for solving the problem]

[0012] In order to achieve the above object, one aspect of the present invention is a tread material for steel frame stairs, A staircase tread for a steel frame, which has a raised piece protruding above the nose of the tread, and is used for curing a recess formed by the tread, the riser, and the raised piece until a cement-based material is poured into the recess, A resin tread piece having a rectangular or approximately rectangular shape in plan view; A pair of resin leg pieces extending downward along a pair of long sides and / or a pair of short sides of the tread; The present invention is characterized in that it has an auxiliary leg piece made of resin, which is provided on the underside of the tread between the pair of legs.

[0013] According to this aspect, a tread for steel frame stairs can be formed that is as light as possible, easy to handle, and not complicated in structure, by having a tread made of resin that is rectangular or approximately rectangular in plan view, a pair of legs made of resin, and a resin auxiliary leg piece provided between the pair of legs on the underside of the tread. Then, by placing and curing this tread for steel frame stairs in the recesses of each step or landing, safety during ascent and descent can be guaranteed until the cement-based material is poured into the recesses.

[0014] In addition, by providing the auxiliary leg between the pair of legs, it is possible to prevent the tread from bending too much with the pair of legs as the fulcrum, and it is possible to form a tread for a steel frame staircase that is lightweight overall but has high rigidity. Here, the auxiliary leg may be one or more.

[0015] Also, by setting the height of the steel staircase treads so that when they are placed in the recesses, they are about the same height as the rising pieces or slightly higher than the rising pieces, preventing tripping caused by the rising pieces and allowing the feet to step on the steel staircase treads with a stable footing. Also, the planar shape and dimensions of the steel staircase treads are generally rectangular or approximately rectangular in plan view, like steps that are generally rectangular in plan view, and are set to planar dimensions that can be easily accommodated in the recesses of each step.

[0016] Another aspect of the steel staircase tread of the present invention is as follows: The one auxiliary leg piece is provided in the center of the pair of legs.

[0017] According to this embodiment, by providing one auxiliary leg piece at the center position of a pair of legs, it is possible to form a tread for steel frame stairs that is lightweight and highly rigid while keeping the structure as simple as possible.

[0018] Another aspect of the steel staircase tread of the present invention is as follows: The leg piece and the auxiliary leg piece are both characterized in that their cross-sectional widths narrow downward.

[0019] According to this embodiment, the leg piece and the auxiliary leg piece each have a cross-sectional shape in which their cross-sectional width narrows downward, so that the storage space formed by the step piece, the leg piece, and the auxiliary leg piece can be made as large as possible, and obstacles (protruding members) present on the step or landing can be easily stored. Such obstacles include spacers for installing reinforcing bars with a specified cover when pouring cement-based materials into the recesses.

[0020] Another aspect of the steel staircase tread of the present invention is as follows: The step piece is characterized in having a mesh structure having a plurality of openings in a plan view.

[0021] According to this embodiment, the tread has a mesh structure with multiple openings when viewed in a plane, which prevents dust and other debris, mud, rainwater, etc. from accumulating on the upper surface of the tread, thereby increasing safety when ascending and descending and making the tread material for steel frame stairs even lighter.

[0022] Another aspect of the steel staircase tread of the present invention is as follows: The openings may be partially or entirely formed in a honeycomb shape in plan view.

[0023] According to this aspect, since the planar shape of some or all of the openings is a honeycomb shape, the rigidity of the step can be increased even while having the openings.

[0024] Another aspect of the steel staircase tread of the present invention is as follows: The step is characterized in that it further comprises a plurality of straight beams along the long and short sides of a rectangle when viewed in plan.

[0025] According to this aspect, the step further includes a plurality of straight beams along the long and short sides of the rectangle in plan view, thereby further increasing the rigidity of the lightweight step having an opening.

[0026] Another aspect of the steel staircase tread of the present invention is as follows: The cross-sectional width of the auxiliary leg piece is smaller than that of the leg piece, The auxiliary leg piece is characterized in that it has reinforcing ribs at regular intervals in a direction along the long side or the short side.

[0027] According to this aspect, the cross-sectional width of the auxiliary leg piece is smaller than that of the leg piece, and the auxiliary leg piece is provided with reinforcing ribs at regular intervals in the direction along the long side or short side, thereby making it possible to make the cross-sectional width of the auxiliary leg piece as small as possible to expand the storage space, while effectively reinforcing the strength of the auxiliary leg piece with multiple reinforcing ribs.

[0028] Another aspect of the steel staircase tread of the present invention is as follows: The step is characterized in that a plurality of minute protrusions are provided on the tread surface of the step piece.

[0029] According to this aspect, by providing a plurality of minute protrusions on the tread surface of the tread piece, the anti-slip performance of the tread surface can be improved.

[0030] Another aspect of the steel staircase tread of the present invention is as follows: It is characterized by its overall yellow color.

[0031] According to this aspect, the entire steel staircase tread is yellow, which can call the attention of workers when ascending and descending the steel staircase. Also, by coloring the members installed in dangerous places in the construction site yellow, it can be shown that the site is well managed for safety.

[0032] In addition, one aspect of the steel staircase according to the present invention is as follows: A steel staircase, comprising: a step formed by the tread, the riser, and the rising piece; and a plurality of steps continuously attached to a stringer, The steel staircase treads are placed in the recesses of each step, and the convex members on the upper surface of the treads are accommodated in the storage space formed by the leg piece, the auxiliary leg piece, and the step piece, thereby protecting the recesses.

[0033] According to this aspect, the steel stair treads of the present invention are installed in the recesses of each step of a steel staircase, and the recesses are cured with the convex members on each tread housed in the accommodation space, thereby preventing interference between the steel stair treads and the convex members, while resulting in a highly safe steel staircase in which the recesses are cured with the steel stair treads.

[0034] In addition, the steel staircase treads of the present invention should be installed and cured not only on each step but also on the recesses of the landing. Here, the convex members are spacers or the like for installing reinforcing bars with a predetermined cover when pouring cement-based materials into the recesses, as described above. Effect of the Invention

[0035] As can be understood from the above description, the steel staircase tread material of the present invention can provide a steel staircase tread material that is as light as possible, easy to handle, and not complicated in structure. In addition, the steel staircase in which the recesses of each step and landing are cured with the steel staircase tread material of the present invention can ensure safety during ascent and descent until the cement-based material is poured into the recesses. [Brief description of the drawings]

[0036] [Figure 1] FIG. 1 is a perspective view of an example of a conventional steel staircase. [Diagram 2] FIG. 2 is an enlarged side view of a step of a conventional steel staircase. [Diagram 3] FIG. 1A is a diagram showing the condition of the ground under a worker's feet when ascending a conventional steel staircase, and FIG. 1B is a diagram showing the condition of the ground under a worker's feet when descending a conventional steel staircase. [Figure 4] FIG. 2 is a perspective view of an example of a tread for a steel frame staircase according to an embodiment, seen obliquely from above. [Diagram 5] 5 is a view taken in the direction of the arrow V in FIG. 4, and is a plan view of an example of a tread for steel frame stairs according to an embodiment, seen from above. [Figure 6] 6 is a view taken in the direction of an arrow VI in FIG. 4, and is a perspective view of an example of a tread for steel frame stairs according to an embodiment, seen obliquely from below. [Figure 7] 5, and is a side view of the steel frame staircase tread member according to the embodiment, seen from the short side thereof. FIG. [Figure 8] 8 is a view taken along the line VIII-VIII of FIG. 5, and is a longitudinal cross-sectional view of the tread for steel frame stairs according to the embodiment cut in the short side direction at a midpoint in the longitudinal direction. [Figure 9] 9 is a view taken along the line IX-IX in FIG. 5, and is a longitudinal cross-sectional view of the tread for steel frame stairs according to the embodiment cut in the short side direction at another intermediate position in the longitudinal direction. [Figure 10] FIG. 5 is an enlarged view of a portion X in FIG. [Figure 11] FIG. 2 is a perspective view showing a state in which a tread for a steel frame staircase according to an embodiment is installed on a step and a landing. [Figure 12] FIG. 2 is a perspective view of an example of a steel staircase according to an embodiment. [Figure 13] FIG. 13 is a diagram showing the state of a worker's feet when ascending a steel staircase according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Hereinafter, an example of a steel staircase tread and a steel staircase according to an embodiment will be described with reference to the accompanying drawings. In this specification and the drawings, substantially the same components are designated by the same reference numerals to avoid redundant description.

[0038] [Steel staircase tread and steel staircase according to the embodiment] An example of a tread member for steel frame stairs and a steel frame staircase according to an embodiment will be described with reference to Figs. 4 to 13 .

[0039] Here, Fig. 4 is a perspective view of an example of a steel frame staircase tread according to the embodiment, seen from diagonally above. Also, Fig. 5, Fig. 6, and Fig. 10 are respectively a view seen from the V direction of Fig. 4, which is a plan view of an example of a steel frame staircase tread according to the embodiment, seen from the top, a view seen from the VI direction of Fig. 4, which is a perspective view of an example of a steel frame staircase tread according to the embodiment, seen from diagonally below, and an enlarged view of the X part of Fig. 4. Also, Fig. 7, Fig. 8, and Fig. 9 are respectively a view seen from the VII direction of Fig. 5, which is a side view of the steel frame staircase tread according to the embodiment, seen from the short side, a view seen from the VIII-VIII arrow of Fig. 5, which is a vertical cross-sectional view of the steel frame staircase tread according to the embodiment cut in the short side direction at a midway position in the longitudinal direction, and a view seen from the IX-IX arrow of Fig. 5, which is a vertical cross-sectional view of the steel frame staircase tread according to the embodiment cut in the short side direction at another midway position in the longitudinal direction. Furthermore, Figure 11 is an oblique view showing the state in which the tread material for steel staircases of the embodiment is installed on the step and landing, Figure 12 is an oblique view of an example of a steel staircase of the embodiment, and Figure 13 is a diagram showing the state of a worker's feet when climbing the steel staircase of the embodiment.

[0040] The steel frame stair tread 60 has a resin tread 20 that is rectangular in plan view, a pair of resin leg pieces 30 that extend downward along a pair of long sides 21 of the tread 20, and a resin auxiliary leg piece 40 that is provided on the underside 24 of the tread 20 between the pair of leg pieces 30 (in the illustrated example, the center position of the pair of leg pieces 30) and extends parallel to the leg piece 30. The auxiliary leg piece 40 in the illustrated example has the same height as the leg piece 30, and the pair of leg pieces 30 and auxiliary leg pieces 40 of the same height can maintain the stable posture of the steel frame stair tread 60, but for example, when the heights of the intended installation locations of the leg piece 30 and auxiliary leg piece 40 are different, the heights of both the auxiliary leg piece 40 and the leg piece 30 may differ slightly depending on the height of the intended installation location.

[0041] Here, "rectangle in plan view" includes shapes with chamfered corners and curved shapes. In addition to the rectangular shape in plan view shown in the figures, the step 20 may have a generally rectangular shape in plan view, such as a shape with curved edges bulging out to the side or a shape with triangular edges bulging out to the side.

[0042] In addition, in the illustrated example, the leg pieces 30 are provided at positions corresponding to the long sides 21 of the tread piece 20, but the leg pieces may also be provided at positions corresponding to the short sides 22 of the tread piece 20, and in this embodiment, one or more auxiliary leg pieces extending parallel to the leg pieces are provided between the leg pieces at positions corresponding to a pair of short sides 22. Furthermore, a form may be provided that includes both a pair of leg pieces 30 at positions corresponding to a pair of long sides 21, and a pair of leg pieces at positions corresponding to a pair of short sides 22.

[0043] The tread 20, leg piece 30, and auxiliary leg piece 40 form a storage space 35 below the tread 20. This storage space 35 is designed to accommodate protruding members P (see FIG. 11) such as spacers for placing reinforcing bars in the recesses 14, 18 when the steel frame staircase tread 60 is installed in the recesses 14, 18 of the step 15 of the steel frame staircase or the recesses 19 of the landing 18. This allows the steel frame staircase tread 60 to be installed in the recesses 14, 18 without interfering with the various types of protruding members P in the recesses 14, 18.

[0044] The length t1 of the long side 21 and the length t2 of the short side 22 of the tread 20 (see Figure 5) are set slightly smaller than the planar dimensions of the rectangular step 15 (see Figure 1) that is provided on a typical steel frame staircase, so that the steel frame staircase tread 60 can be smoothly inserted and installed into the recess 14 of the step 15, and the installed steel frame staircase tread 60 is less likely to slip within the recess 14, which is preferable.

[0045] As an example, the length t1 can be set to about 850 mm to 1200 mm, such as 870 mm, and the length t2 can be set to about 200 mm to 250 mm, such as 235 mm.

[0046] Moreover, the height t3 (see FIG. 7) of the steel staircase tread 60 is set to be about the same height as the rising piece 12 that forms the recess 14 or slightly higher than the rising piece 12 when it is placed in the recess 14 of the step 15, which is preferable because it prevents tripping over the rising piece 12 and allows the footing to be stable when stepping on the tread 20 of the steel staircase tread 60. As an example, the height t3 can be set to about 50 mm to 60 mm, for example 52 mm.

[0047] The steel staircase tread 60 is made entirely of resin, and is lighter and easier to handle than conventional metal curing materials. The resin material can be made of relatively hard and versatile materials such as polypropylene (PP), polyethylene (PE), and polystyrene (PS).

[0048] In addition, it is preferable that the steel staircase tread 60 is yellow in its entirety. For example, it may be produced by mixing a yellow dye into a resin material and molding it as one piece, or by coloring it yellow after molding (by applying paint or immersing it in paint, etc.).

[0049] The entire steel staircase tread 60 is yellow in color, which alerts workers to be careful when ascending or descending the steel staircase, and since the components installed in potentially dangerous locations on the construction site are yellow, it is preferable because it shows that the site has thorough safety management.

[0050] The steel staircase tread 60 can be manufactured efficiently by integral molding using a resin material. In addition, since the entire tread is made of resin and is as lightweight as possible, it can be easily installed in the recesses 14, 19 of the many steps 15 and landings 18 of the steel staircase 10, and can also be easily removed before pouring cement-based materials into the recesses 14, 19.

[0051] A narrow beam 25 extending in the longitudinal direction is provided on the step 20 at a position corresponding to the pair of long sides 21 (directly above the pair of leg pieces 30). More specifically, a beam 25 is provided at a position corresponding to the long sides 21, and a separate beam 25 is similarly provided at an interval t2'. Thus, a pair of beams 25 are provided at each of a pair of ends along the longitudinal direction of the step 20 (the areas of the long sides 21).

[0052] Between the pair of beams 25, a plurality of openings are provided along the longitudinal direction, each of which has a trapezoidal, triangular or rectangular shape (one example of a rectangle) in plan view, which is half the honeycomb shape.

[0053] A beam 26 parallel to the long side 21 is also provided at the center of the step 20 in a plan view (directly above the auxiliary leg 40).

[0054] As shown in Figures 8 and 9, the beams 25, 26 in the illustrated example extend so as to be continuous with the leg piece 30 and the auxiliary leg piece 40, thereby enhancing the unity of the leg piece 30, the auxiliary leg piece 40 and the tread piece 20.

[0055] On the other hand, at positions of the step 20 corresponding to the short sides 22 and at multiple locations between the pair of short sides 22, multiple beams 27 extending parallel to the short sides 22 and perpendicular to the beams 25, 26 are provided spaced apart in the longitudinal direction.

[0056] Here, the height of the beams 25, 26, 27 can be set to, for example, about 20 mm, and therefore the height t4 of the leg piece 30 and the auxiliary leg piece 40 in FIG. 7 can be set to about 30 to 40 mm, which is the difference between the height t3 and the beam 25, etc.

[0057] Between the beams 25, 26 and the beam 27, there are provided an opening 28 having a honeycomb shape in a plan view, an opening 29 having a rectangular shape in a plan view, and an opening having a triangular shape in a plan view.

[0058] In this way, because the tread piece 20 has a mesh structure with numerous openings 28, 29, etc., combined with the fact that the tread piece 60 for steel frame stairs is made of resin, the tread piece 20 can be made even lighter, which leads to an even lighter weight of the tread piece 60 for steel frame stairs.

[0059] In addition, while the tread 20 has numerous openings 28, 29, etc., the tread 20 is provided with a plurality of beams 25, 26 extending in the longitudinal direction and a plurality of beams 27 extending in the lateral direction, and further, some of the openings include openings 28 which have a honeycomb shape when viewed in a plane, thereby increasing the rigidity of the tread 20 and forming a tread 20 which is load-bearing when stepped on by workers, etc.

[0060] In addition, the presence of numerous openings 28, 29, etc. on the tread surface 23 of the tread 20 prevents dust and other debris, mud, rainwater, etc. from accumulating on the tread surface 23 of the tread 20, thereby eliminating the slippery feeling caused by such debris, rainwater, etc., thereby increasing safety for workers ascending and descending when the steel staircase tread 60 is installed in the recess 14 of the step 15.

[0061] 4, 5, 10, etc., a large number of minute protrusions 50 are provided on the tread surface 23 of the step 20. The height t9 (see FIG. 10) of the minute protrusions 50 can be set to about 1 mm to 5 mm, for example, 2 mm.

[0062] In this way, by providing a large number of tiny convexities 50 on the tread surface 23 of the tread 20, the anti-slip performance of the tread surface 23 can be improved, and together with the above-mentioned elimination of the accumulation of dirt, mud, rainwater, etc., the safety of workers when ascending and descending can be further increased.

[0063] As shown in FIG. 7, both the leg piece 30 and the auxiliary leg piece 40 have a cross-sectional shape in which the cross-sectional width narrows downward.

[0064] Specifically, the leg piece 30 has a width t6 at its lower end which is narrower than the width t5 at the joint with the step piece 20, and the auxiliary leg piece 40 has a width t8 at its lower end which is narrower than the width t7 at the joint with the step piece 20.

[0065] For example, the width t5 can be set to about 24 mm to 26 mm, e.g., 25 mm, the width t6 can be set to about 22 mm to 24 mm, e.g., 23 mm, the width t7 can be set to about 5 mm to 8 mm, e.g., 7 mm, and the width t8 can be set to about 4 mm to 7 mm, e.g., 6 mm.

[0066] In this way, since both the leg piece 30 and the auxiliary leg piece 40 have a cross-sectional shape in which their cross-sectional width narrows downward, and the width of the auxiliary leg piece 40 is narrower than that of the leg piece 30, the storage space 35 can be set as wide as possible, making it possible to store protruding members P of various sizes and shapes.

[0067] As shown in FIG. 6, the auxiliary leg piece 40 is provided with reinforcing ribs 45 at regular intervals in the longitudinal direction.

[0068] By providing a plurality of reinforcing ribs 45 in this manner, the cross-sectional width of the auxiliary leg piece 40 can be made as small as possible to widen the accommodation space 35, while effectively reinforcing the strength of the auxiliary leg piece 40.

[0069] FIG. 11 shows a state in which steel staircase treads 60 are installed in the uppermost step 15 among a plurality of steps 15 and in each of the recesses 14, 19 of the landing 18 following the uppermost step 15.

[0070] In the illustrated example, a plurality of (four in the illustrated example) angled convex members P, which are spacers for reinforcing bars, are welded to the landing 18, and each steel frame stair tread 60 is installed in the recess 19 with the convex members P accommodated in the accommodation space 35 of each steel frame stair tread 60. Although not shown in the illustration, a convex member is also welded to the tread of the step 15.

[0071] As shown in Fig. 12, by installing steel staircase treads 60 in the recesses 19, 14 of the upper and lower landings 18 and the steps 15 connecting them, a steel staircase 80 is formed in which each recess 19, 14 is covered with the steel staircase treads 60. Here, handrails 70 are attached to the steel staircase 80.

[0072] As shown in Figure 13, by installing non-slip steel staircase tread material 60 in the recesses 14 of each step 15, the recesses 14 are cured to have flat tread surface 23, making it easy to ascend and descend, and preventing slipping when ascending and descending, a steel staircase 80 is created that can guarantee safety when ascending and descending until the cement-based material is poured into the recesses 14.

[0073] Furthermore, even when there are many steps 15, the steel staircase 80 can be easily formed by smoothly installing the lightweight steel staircase treads 60 in the recesses 14 of each step 15, and when pouring the cement-based material, the steel staircase treads 60 can be smoothly removed from the recesses 14 of each step 15.

[0074] The present invention is not limited to the configurations shown here, and may be implemented in other embodiments in which other components are combined with the configurations and the like set forth in the above embodiments. In this regard, the present invention may be modified without departing from the spirit of the present invention, and may be appropriately determined according to the application form. [Explanation of symbols]

[0075] 10: Steel staircase 11: Step piece 11a: Nosing 12: Rising piece 13: Knob 14: Recess 15: Step 17: stringer 18:Landing 19: Recess F: Worker (at feet) P: Convex member 20: Step piece 21: Long side 22: Short side 23:Top surface (tread surface) 24: Bottom surface 25: Beam (longitudinal end beam) 26: Beam (longitudinal central beam) 27: Beam (short direction beam) 28: Opening (honeycomb opening) 29: Opening (rectangular opening) 30: Leg piece 35: Containment Space 40: Auxiliary leg piece 45: Reinforcement rib 50: Micro-projection 60: Steel staircase tread 70: Handrail 80: Steel staircase

Claims

1. A staircase tread for a steel frame, which has a raised piece protruding above the nose of the tread, and is used for curing a recess formed by the tread, the riser, and the raised piece until a cement-based material is poured into the recess, A resin tread piece having a rectangular or approximately rectangular shape in plan view; A pair of resin leg pieces extending downward along a pair of long sides and / or a pair of short sides of the tread; A tread material for steel frame stairs, characterized in that it has an auxiliary leg piece made of resin provided between the pair of legs on the underside of the tread.

2. 2. The tread for a steel frame staircase according to claim 1, wherein one of the auxiliary leg pieces is provided at a central position of the pair of leg pieces.

3. 2. The tread for a steel frame staircase according to claim 1, wherein the leg piece and the auxiliary leg piece each have a cross-sectional shape in which their cross-sectional width narrows downward.

4. 2. The steel staircase tread material according to claim 1, wherein the tread piece has a mesh structure having a plurality of openings in a plan view.

5. 5. The tread for a steel frame staircase according to claim 4, wherein a planar shape of part or all of the openings is a honeycomb shape.

6. 5. The steel staircase tread material according to claim 4, wherein the step further comprises a plurality of straight beams along the long and short sides of a rectangle in plan view.

7. The cross-sectional width of the auxiliary leg piece is smaller than that of the leg piece, 2. The tread member for a steel frame staircase according to claim 1, wherein the auxiliary leg piece is provided with reinforcing ribs at regular intervals along the long side or the short side.

8. 2. The tread material for steel frame stairs according to claim 1, wherein a plurality of minute protrusions are provided on the tread surface of the tread piece.

9. 2. The tread material for steel frame stairs according to claim 1, characterized in that the tread material is yellow in color as a whole.

10. A steel staircase, comprising: a step formed by the tread, the riser, and the rising piece; and a plurality of steps continuously attached to a stringer, A steel staircase, characterized in that a tread material for a steel staircase as described in any one of claims 1 to 9 is installed in the recess provided in each step, and a convex member present on the upper surface of the tread is accommodated in the storage space formed by the leg piece, the auxiliary leg piece and the step piece, thereby protecting the recess.

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