Simple staircase

Abstract

The present invention discloses an improvement for suppressing the slipping of shoes in a simple staircase installed on an inclination such as a slope or a mountain path. A beam member 3 of each step in this simple staircase 1 has a tubular section 11 that is stepped on with the arch portion or heel portion of a shoe 61 of a person climbing or descending the staircase 1, and a flange section 13 that is stepped on with the front half of the shoe 61 of a person climbing the staircase 1. An upper surface 11A of the tubular section 11 is curved in an arc shape and bulges further upward than an upper surface 13A of the flange section 13. A plurality of large protrusions 15 having a relatively large size are installed upright in a plurality of locations in the vicinity of an open edge of the upper surface 11A of the tubular section 11. A plurality of small protrusions 17 having a relatively small size are installed upright on the upper surface 13A of the flange section 13.

Description

simple stairs

[0001] The present invention relates to stairs that can be easily installed on inclined surfaces such as mountain slopes and slopes.

[0002] The mountain path stairs described in Patent Documents 1 and 2 each comprise two flexible long girder supports, a number of girder members fixed between them at regular intervals in the longitudinal direction, and a number of piles that secure the girder members to the ground, and can be easily installed on a slope.

[0003] Japanese Utility Model Application No. 60-57117 (Japanese Utility Model Application Laid-Open No. 61-173544) Microfilm Japanese Utility Model Application Laid-Open No. 3-49136

[0004] There is a demand for this type of simple staircase to prevent slippage between the shoes and the beams of people going up and down the stairs. It is especially desirable that the surface of the beams or the soles of the users' shoes are not slippery even when they are wet or covered with snow or mud due to snowfall or rain. It is also especially desirable that slippage be prevented when people are going down the stairs. Furthermore, it is desirable that the stairs can be used on slopes with steeper inclines than conventional stairs.

[0005] An object of the present invention is to improve the ability to prevent slippage between shoes and beam members in simple stairs.

[0006] Another object is to make the simple staircase applicable to steeper slopes.

[0007] Other objects of the present invention will become apparent from the following description.

[0008] The simplified staircase according to one embodiment includes a plurality of beam members each forming a plurality of steps, one or more vertical connecting members connecting the beam members in the vertical direction at intervals, and a plurality of fixing stakes for fixing the beam members to the sloping ground. At least one beam member has one or more first protrusions erected at one or more locations on the front portion of its upper surface and one or more second protrusions erected at one or more locations on the rear portion of its upper surface. The one or more second protrusions are higher in height than the one or more first protrusions.

[0009] According to one embodiment, the one or more secondary projections are larger in lateral dimension than the one or more primary projections.

[0010] According to one embodiment, the one or more secondary projections are larger in vertical dimension than the one or more primary projections.

[0011] According to one embodiment, the one or more first projections or the one or more second projections are elongated in the transverse direction and curved in a wave-like shape in a plan view.

[0012] According to one embodiment, at least one beam member has a tube portion for receiving the arch or heel portion of the sole of a shoe of a person going up or down the simple staircase, and a flange portion protruding forward from the front end of the tube portion for receiving the front half of the sole of a shoe of a person going up or down the simple staircase. One or more first protrusions are provided on the upper surface of the flange portion, and one or more second protrusions are provided on the upper surface of the tube portion.

[0013] According to one embodiment, one or more second projections are provided on the upper surface of the cylindrical portion near the rear end thereof.

[0014] According to one embodiment, the upper surface of the cylindrical portion is curved in an arc shape in a side view and bulges upward from the upper surface of the flange portion.

[0015] According to one embodiment, the simple staircase has a front half portion from the highest point on the top surface of the tubular portion to the boundary with the flange portion, which is inclined rearward and upward relative to the top surface of the flange portion.

[0016] According to one embodiment, one or more longitudinal connecting members are attached to each girder member by fixed pegs without the use of separate fasteners.

[0017] According to one embodiment, the beam members have lateral connection mechanisms for connecting laterally with other beam members.

[0018] 1 is a perspective view showing a simple staircase according to one embodiment installed on sloping ground; FIG. 1 is a perspective view of a girder member of the simple staircase, viewed diagonally from above the front right; FIG. 2 is a perspective view of the girder member, viewed diagonally from above the front left; FIG. 3 is a plan view of the girder member; FIG. 4 is a left side view of the girder member; FIG. 5 is a right side view of the girder member (also showing an example of the positional relationship with the shoe when a user goes up the stairs); FIG. 6 is a right side view of the girder member (also showing an example of the positional relationship with the shoe when a user goes down the stairs); FIG. 7 is a front view of the girder member; FIG. 8 is a rear view of the girder member; FIG. 9 is a bottom view of the girder member; FIG. 10 is a photograph and explanatory diagram of a structure for connecting two girder members horizontally, viewed from the bottom; FIG. 11 is a plan view of a modified vertical connecting member; FIG. 12 is a left side view showing an example of a structure for attaching a vertical connecting member to a girder member using a fixed stake;

[0019] An embodiment of the present invention will be described below.

[0020] As shown in Figure 1, a simple staircase 1 according to one embodiment is installed on a sloping ground 2, such as a mountain trail, a pylon inspection route, or a slope. In the following description, when describing the positional relationship or direction of the simple staircase 1 and its components, the directions or sides in front, behind, right, left, up, and down as seen from a person climbing the simple staircase 1 will be referred to as the "front," "rear," "right," "left," "up," and "down" directions or sides. The left-right direction will also be referred to as the "horizontal" direction, the front-back direction will be referred to as the "vertical" direction, and the up-down direction will be referred to as the "vertical" direction.

[0021] The simple staircase 1 has a plurality of girder members 3 that form each of the multiple steps of the staircase, one or more (e.g., a pair of left and right) vertical connecting members 5 that vertically connect the girder members 3 of different steps to each other, and one or more (e.g., a pair of left and right) fixing stakes 7 that fix each girder member 3 to the ground 2.

[0022] The girder member 3 is a horizontally long, columnar object that is installed on the ground 2 with its longitudinal direction roughly aligned with the horizontal direction. The girder member 3 has sufficient strength and rigidity required for an outdoor staircase, and is weather-resistant to withstand wind and rain. It is desirable that the girder member 3 be as lightweight as possible so that it can be easily carried by people, and that it be low-cost. Taking these conditions into consideration, the girder member 3 is made of, for example, FRP (fiber reinforced plastic), and is manufactured as a single unit by molding, for example, but the material and manufacturing method are not limited to this.

[0023] Each girder member 3 is fixed to the ground 2 using, for example, a pair of left and right fixing posts 7. Specifically, first through-holes 19 (see FIG. 4 ) are provided at two locations near the left and right ends of the rear of the girder member 3, and two fixing posts 7 are inserted into these first through-holes 19, respectively. The fixing posts 7 are driven into the ground to their maximum depth using a hand hammer or similar. The heads 7A of the fixing posts 7 are larger than the inner diameter of the first through-holes 19, and these heads 7A press the girder member 3 against the ground 2, thereby fixing the girder member 3 to the ground 2. The surface of the fixing posts 7 that enter the ground has many convex or concave portions (not shown), which make it difficult for the fixing posts 7 to be pulled out of the ground. It is desirable that the fixing posts 7 have sufficient strength and rigidity to penetrate and split underground tree roots and rocks, and also be resistant to corrosion and deterioration. Taking such conditions into consideration, the fixed piles 7 are made of, for example, rust-proof or rust-resistant steel, but the material is not limited to this.

[0024] One or more vertical connecting members 5, for example, a pair of left and right vertical connecting members 5, connect multiple girder members 3 on different floors in the vertical direction at an arbitrary interval. Each vertical connecting member 5 is, for example, a long, thin rod or rope, and has a length of, for example, about 5 to 10 meters. It is placed vertically on the sloping ground 2 and fixed to multiple girder members 3. That is, each girder member 3 has two second through holes 23 (see FIG. 4) near the left and right ends of its front part. Parts for fixing each vertical connecting member 5 are attached to each of these two second through holes 23, and each vertical connecting member 5 is fixed to the parts. This fixing method can be a known method, for example, the method shown in FIG. 8 of the aforementioned Patent Document 2. According to this method, a J-shaped hook bolt is inserted into the second through-hole 23 with its threaded portion projecting upward and its hook portion projecting downward, and a rod- or rope-shaped vertical connecting member 5 is sandwiched between the hook portion of the hook bolt and the underside of the girder member 3. Then, by tightening a nut threaded onto the threaded portion of the hook bolt, the vertical connecting member 5 is firmly fixed between the hook portion and the underside of the girder member 3.

[0025] The shape of each vertical connecting member 5 is not limited to a thin rod or rope shape. For example, the vertical connecting member 5 may be a net-like or perforated sheet-like component as shown in Figures 1 to 3 of Patent Document 2. In this case, similar to the fixing method described in Patent Document 2, the vertical connecting member 5 may be fixed to the girder member 3 by a fastener using a screw bolt inserted through the second through-hole 23. Note that, although Figures 1 to 3 of Patent Document 2 show two net-like or perforated sheet-like vertical connecting members connecting multiple girder members, instead, a single net-like or perforated sheet-like vertical connecting member with a wider width than that described in Patent Document 2 may be used to connect multiple girder members 3 in the vertical direction.

[0026] The vertical connecting members 5 maintain a constant positional relationship (spacing) between the multiple beam members 3. Furthermore, even if some soil on the sloping ground surface 2 is washed away or collapsed by running water, the vertical connecting members 5 connect the multiple beam members 3 to other beam members 3, preventing them from being washed away or falling along with the soil.

[0027] The vertical connecting members 5 have sufficient strength, rigidity, and weather resistance for the above purposes. Furthermore, since the simplified stairs 1 also need to be curved on a curved ramp, it is desirable that the vertical connecting members 5 have a certain degree of flexibility so that they can be bent. Furthermore, it is desirable that the vertical connecting members 5 be as lightweight as possible and low-cost so that they can be easily carried by people. Taking these conditions into consideration, the vertical connecting members 5 are made of, for example, FRP (fiber reinforced plastic), but the material is not limited to this.

[0028] The girder member 3 will be described in more detail below with reference to FIGS. 2 to 11.

[0029] As shown in Fig. 4, the horizontal dimension (length) L1 of the beam member 3 is approximately the minimum value that would be required for the width of a staircase for people to ascend and descend, for example, about 40 cm to about 60 cm (e.g., 50 cm). The vertical dimension (depth) D1 of the beam member 3 is approximately the minimum value that would be required to support the shoes of a person climbing the stairs and prevent them from slipping when they step on the beam member 3, for example, about 8 cm to about 12 cm (e.g., about 10 cm) (i.e., about one-third to one-half the vertical dimension of an average adult shoe). As shown in Fig. 5, the vertical dimension (height) H1 of the beam member 3 is approximately the minimum value that would be required for the height of a single staircase step, for example, about 7 cm to about 12 cm (e.g., about 9 cm).

[0030] The girder member 3 has a tubular portion 11 and a flange portion 13, which are formed as an inseparable, integrated part, for example, by molding. As can be seen from Figures 1, 2, 5, and 6, the tubular portion 11 has a shape that resembles a hollow, approximately elliptical cylindrical object (the minor diameter in the vertical direction of the approximately elliptical cross section is, for example, about 7 cm to about 8 cm, and the major diameter in the vertical direction is, for example, about 10 cm to about 13 cm) with its left and right ends closed, cut along a linearly inclined plane extending from the upper front to the lower rear, and removing a portion equivalent to about one-third of the area of ​​the lower front side in a side view.

[0031] As shown in Figure 4, first through holes 19 are provided in two locations near both the left and right ends of the tubular portion 11. Around each first through hole 19, a pocket 21 is formed, which is recessed downward from the upper surface 11A of the tubular portion 11 and has a flat bottom. This pocket 21 accommodates the head of the fixed post 7 inside, preventing the head from protruding above the upper surface 11A of the tubular portion 11.

[0032] A surface 35 (Fig. 5) corresponding to the inclined cut surface of the cylindrical portion 11 is the contact surface that comes into contact with the inclined ground surface 2. The cylindrical portion 11 corresponds to the riser, nosing, and part of the tread (the part close to the nosing) of a typical staircase. The external shape of the cylindrical portion 11, which is a roughly elliptical cylinder, imitates the logs that have long been used as primitive, simple staircases, and easily blends in with the mountain landscape.

[0033] As shown in FIGS. 6 and 7, the cylindrical portion 11 is usually stepped on by the arch or heel of the sole of the shoe 61 of a person going up or down the simple staircase 1.

[0034] The flange 13 of the beam member 3 extends over almost the entire length of the cylindrical portion 11, protruding forward from the front end near the top of the cylindrical portion 1 by a certain distance, for example, about 3 cm to 5 cm (e.g., 3.5 cm), and is generally rectangular in plan view (FIG. 4). The flange 13 corresponds to part of a tread in a typical staircase (i.e., the flat portion that is located forward, for example, about 6 cm to 12 cm, or for example, about 7 cm to 10 cm, from the nosing).

[0035] As shown in Figure 4, second through holes 23 are provided in two locations near both the left and right ends of the flange 13. Around each second through hole 23, a pocket 25 is formed, which is recessed downward from the upper surface 13A of the flange 13 and has a flat bottom. The bottom of this pocket 25 provides a seat for a device for fixing the vertical connecting member, such as the locking nut of the hook bolt described above or the head of the screw bolt described above.

[0036] As shown in Figure 6, in most cases, the flange 13 is stepped on by the part of the sole (the part that is subjected to a large load and kicking force when climbing) directly below the ball of the foot 65 (the base of the five toes) from the ball of the big toe to the ball of the little toe of the foot 63 of a person climbing the simple staircase 1, in other words, the front half of the sole (the part forward of the arch).

[0037] As can be seen from Figure 5, the upper surface 13A of the flange 13 is flat. When the inclination angle θ of the sloping ground 2 on which the girder member 3 is installed relative to the horizontal direction 41 is a predetermined angle θ (for example, approximately 30 degrees to approximately 45 degrees, e.g., approximately 35 degrees), the flange upper surface 13A is horizontal. A contact surface 37 that will come into contact with the sloping ground 2 is located at the bottom of the front end of the flange 13. The contact surface 37 of the flange 13 is located on an extension of the contact surface 35 of the tubular portion 11.

[0038] 5, the upper surface 11A of the tubular portion 11 is curved in an arc shape in a side view and bulges upward from the upper surface 13A of the flange portion 13 by a predetermined height H2 (e.g., about 10 mm to about 30 mm, e.g., about 15 mm). Therefore, a portion of the upper surface 11A of the tubular portion located near the boundary line with the upper surface 13A of the flange is inclined upward and rearward from the upper surface 13A by a predetermined angle φ (e.g., about 10 degrees to about 30 degrees, e.g., about 20 degrees). When the upper surface 13A of the flange is horizontal, the front half portion 11B of the upper surface 11A (the portion close to the upper surface 13A of the flange) is inclined upward and rearward from the horizontal.

[0039] The upward bulge of the tubular upper surface 11A and the upward rearward inclination of its front half 11B prevent the shoes of a person descending the simple staircase 1 from slipping backward (for the person) when stepping on the beam member 3. The above-mentioned bulge and inclination of the tubular upper surface 11A also make it possible to install the beam member 3 on a sloped ground 2 that is slightly steeper than the inclination angle θ (for example, about 40 degrees) shown in Figure 5 (an angle smaller than the above-mentioned predetermined angle φ, for example, about 10 degrees). In other words, when the beam member 3 is installed on such a steeply inclined ground 2, the flange upper surface 13A inclines upward and forward, but the front half 11B of the tubular upper surface 11A provides a level footing.

[0040] As shown in FIG. 4 , a plurality of small protrusions 17 are erected at intervals in the horizontal and vertical directions on the upper surface 13A of the flange 13, substantially along the entire length of the flange 13 (excluding the pockets 25, 25 at both ends). As can be seen from FIGS. 2 to 4 , the small protrusions 17 are arranged in multiple horizontal columns (e.g., 10 columns) and multiple vertical rows (e.g., 2 rows). Each small protrusion 17 has a horizontally elongated shape in plan view, with its horizontal dimension being longer than its vertical dimension. For example, the thickness of the small protrusion 17 in plan view is, for example, about 3 mm to about 7 mm (e.g., about 4 mm), its vertical dimension including curvature is, for example, about 7 mm to about 12 mm (e.g., about 10 mm), and its horizontal dimension is, for example, about 20 mm to about 40 mm (e.g., about 30 mm). The height of each small protrusion 17 is, for example, about 3 mm to about 7 mm (e.g., about 4.5 mm). Each small protrusion 17 is curved in a wave shape in plan view, and has a portion extending in the horizontal direction and a portion extending in a direction oblique to the horizontal direction.

[0041] The small protrusions 17 on the flange upper surface 13A are particularly useful for preventing slippage between a person's shoes and the beam 3 when climbing the simple staircase 1. As previously mentioned, as shown in FIG. 6 , people climbing stairs 1 often step on the flange 13 with the front half of their shoe soles and apply a kicking force to the front half of the sole to move forward. To transfer this kicking force to the ground, the front half of the sole of many shoes has slip-reducing irregularities. The horizontally elongated, wavy curved shape of the small protrusions 17 on the flange upper surface 13A, their relatively small vertical dimensions, and their arrangement in multiple rows and columns allow the small protrusions 17 to engage with the irregularities on the front half of the sole, making it difficult for the shoe 61 to slip vertically and horizontally. In this way, the small protrusions 17 on the flange upper surface 13A primarily prevent slippage between the shoe 61 and the beam 3 of a person climbing stairs 1.

[0042] The gaps between these small protrusions 17 provide a path for mud, soil, snow, etc., to flow out of the flange upper surface 13A when it gets on the flange upper surface 13A, thereby preventing the mud, soil, snow, etc. from accumulating on the flange upper surface 13A. This action also helps prevent slippage between the shoe 61 and the beam member 3.

[0043] As can be seen from Figures 4 to 7, multiple large protrusions 15 are erected at intervals in the horizontal direction at multiple locations along substantially the entire length of the tubular portion 11 (excluding the pockets 21, 21 at both ends), near the rear end of the tubular portion 11, slightly rearward and downward from the top of the upper surface 11A of the tubular portion 11. As can be seen from Figures 2 to 7, each large protrusion 15 on the tubular portion upper surface 11A is larger in horizontal dimension, vertical dimension, and height than each small protrusion 17 on the flange upper surface 13A (e.g., approximately 1.3 to 3 times larger, with the height being particularly notably approximately 3 times larger). Multiple large protrusions 15 (e.g., six) are arranged in a horizontal row. Each large protrusion 15 has a horizontally elongated shape in a plan view, and its horizontal dimension is larger than its vertical dimension. For example, the thickness of the large protrusion 15 in a plan view is, for example, about 3 mm to about 7 mm (e.g., about 5 mm), the vertical dimension including the curvature is, for example, about 10 mm to about 20 mm (e.g., about 15 mm), and the horizontal dimension is, for example, about 45 mm to 70 mm (e.g., about 55 mm). The height of each protrusion 16 is, for example, about 10 mm to about 20 mm (e.g., about 15 mm). Furthermore, each large protrusion 15 is curved in a wavy shape in a plan view, and has a portion extending laterally and a portion extending diagonally relative to the horizontal direction.

[0044] The multiple large protrusions 15 on the upper surface 11A of the tubular portion help prevent slippage between a person's shoes 61 and the beam members 3 when going up and down the simple staircase 1. As mentioned above, as shown in FIG. 6, people going up the stairs 1 usually step on the tubular portion 13 with the arch of their shoe sole or the area nearby. Also, as shown in FIG. 7, people going down the stairs 1 usually step on the tubular portion 13 with the heel of their shoe sole. Therefore, whether going up or down the stairs, the multiple large protrusions 15 on the upper surface 11A of the tubular portion usually come into contact with the arch or heel of the shoe sole. The arch portion of the sole of most shoes is relatively deeply recessed upward, and the heel portion has a slip-preventing unevenness. The large height of the plurality of large projections 15 on the upper surface 11A of the tubular portion allows the large projections 15 to engage with the large recesses in the arch and heel of the sole, thereby preventing the shoe 61 from slipping in the vertical direction. The wavy shape of the large projections 15 also prevents the shoe 61 from slipping in the lateral direction.

[0045] Furthermore, in the unlikely event that the heel of a person descending the stairs 1 slips on the tube portion 11 and slides backward (forward from the person's perspective), the heel is caught by the large protrusion 15 that stands tall on the upper surface 11A of the tube portion. As described above, the large protrusion 15 is relatively large in size, and therefore has great strength, so that even if the heel of the shoe 61 hits it with great force, it can withstand the impact and firmly stop the heel.

[0046] 4, the lateral spacing (gap width) S between the multiple large protrusions 15, 15, ... is set to be wide enough to allow mud and snow on the upper surface 11A of the tubular portion to be washed away outside the tubular portion 11, but narrow enough so that the heel portion of the shoe heel 61 cannot pass through the gap. As a result, as described above, when the heel portion of the shoe 61 of a person descending the stairs 1 slips, the heel portion is highly reliably caught by the large protrusions 15, 15, .... Considering the shoe sizes of not only adults but also children, the gap distance S between the large protrusions 15, 15, ... is preferably, for example, about 1 cm to about 5 cm, and more preferably about 1 cm to about 3.5 cm.

[0047] As can be seen from Figures 3, 8 and 10, a plurality of reinforcing ribs 51 are provided on the inner surface of the girder member 3 to increase the strength while reducing the overall weight of the girder member 3.

[0048] 3 and 8, the two first through holes 19 on the left and right sides of the girder member 3 are each defined by a linearly extending cylindrical wall 31 having a length close to the overall height H1 of the girder member 3. These two cylindrical walls 31 regulate the direction of the fixed piles 7 inserted into the two first through holes 19.

[0049] As can be seen from Figures 2 to 12, two walls at both lateral ends of the girder member 3 are each provided with a connecting mechanism for connecting the girder member 3 to another girder member 3 in the lateral direction without any gaps. The lateral connecting mechanism includes an engaging protrusion 27 and an engaging recess 33. For example, the engaging protrusion 27 is provided on the left end wall of the girder member 3, and the engaging recess 33 is provided on the right end wall. A bolt through-hole 29 is drilled in the center of the engaging protrusion 27, passing through it in the lateral direction. A bolt through-hole 34 is drilled in the center of the engaging recess 33, passing through it in the lateral direction.

[0050] The engaging protrusion 27 protrudes to the right from the outer surface of, for example, the left end wall of the girder member 3. The shape of the engaging protrusion 27 is a trapezoidal column extending vertically, and in plan view, it is a trapezoid whose dimensions increase toward the right. The engaging recess 33 is recessed to the left from the outer surface of, for example, the right end wall of the girder member 3. The shape of the engaging recess 3 corresponds to the shape of the engaging protrusion 27. Therefore, by inserting the engaging protrusion 27 of one girder member 3 vertically into the engaging recess 33 of another girder member 3, a fit is formed that has virtually no gap between them and will not separate even if pulled laterally.

[0051] As shown in Figure 12, when the engaging protrusion 27 of one girder member 3 is fully engaged with the engaging recess 33 of another girder member 3, the bolt through-hole 29 in the engaging protrusion 27 and the bolt through-hole 34 in the engaging recess 33 are aligned in a straight line. Then, by inserting a connecting bolt 53 into the bolt through-holes 29, 34 and tightening a nut 55, the engaging protrusion 27 and the engaging recess 33 are firmly fastened together. In this way, the two girder members 3, 3 are connected laterally, doubling the width of the staircase 1. If three or more girder members 3, 3 are connected laterally in the same way, the width of the staircase 1 can be tripled or more.

[0052] Fig. 12 shows a vertical connecting member 71 according to a modified example. Fig. 13 shows an example of a method for vertically connecting a girder member 3 to a girder member 3 of another floor using the vertical connecting member 71.

[0053] As shown in Figure 12, the vertical connecting member 71 according to this modified example is slender, rod-like, or rope-like, and is made of a strong yet flexible material such as FRP. The overall length of the vertical connecting member 71 corresponds to the maximum allowable distance (e.g., approximately several tens of centimeters to approximately 1 meter) between two vertically aligned beam members 3, 3. The front end of the vertical connecting member 71 is provided with multiple (e.g., three) pile engagement rings 73 at different vertical positions, and the rear end is also provided with multiple (e.g., two) pile engagement rings 73 at different vertical positions. When a fixed pile 7 is inserted through the central hole of each pile engagement ring 73, the inner surface of the central hole abuts against the outer surface of the fixed pile 7 with moderate pressure. Due to the friction between the pile engagement rings 73 and the fixed pile 7, the vertical connecting member 71 will not detach from the fixed pile 7 unless a person attempts to remove it from the fixed pile 7 with considerable force.

[0054] As shown in Figure 13, when one girder member 3 is fixed to the ground with a fixed pile 7, the fixed pile 7 is inserted into one pile engagement ring 73 at the front end of a vertical connecting member 71 from another adjacent girder member 3 (not shown) and, at the same time, into one pile engagement ring 73 at the rear end of another vertical connecting member 71 from another adjacent girder member 3 (not shown), thereby attaching those vertical connecting members 71 to that girder member 3. In this case, there is no need to separately fix the vertical connecting member 71 to the girder member 3 using a separate part, which simplifies the installation of the simple staircase 1. The distance between the two girder members 3 can be adjusted in multiple stages by selecting the pile engagement ring 73 through which the fixed pile 7 is passed.

[0055] When the fixed piles 7 are used for both fixing the girder members 3 and fixing the vertical connecting members as described above, a longer (for example, several meters to 10 meters) rod- or rope-like vertical connecting member capable of vertically connecting three or more tiers of girder members 3 can be used instead of the vertical connecting member 71 having the length between adjacent girder members 3 shown in Figure 12. Such a longer vertical connecting member has multiple pile engaging rings 73 as shown in Figure 12 not only at both ends but also at various points in the middle. In this case, too, the spacing between the girder members 3 can be changed by selecting the pile engaging rings 73 with which the fixed piles 7 engage.

[0056] As a further modification, one or more vertical connecting members in the form of a net or a perforated sheet, as shown in Figures 1 to 3 of Patent Document 2, may be used, and the net or perforated sheet vertical connecting members may be attached to each girder member 3 using only fixed piles 7, without using any additional mounting fixtures.

[0057] The simple staircase and its components according to the embodiment described above are merely examples for the purpose of illustration, and the present invention can be embodied in various different forms without departing from the spirit and scope of the present invention.

[0058] 1: Simple staircase, 2: Inclined ground, 3: Beam member, 5: Vertical connecting member, 7: Fixed pile, 11: Cylindrical portion, 11A: Upper surface of cylindrical portion, 11B: Front half of upper surface of cylindrical portion, 13: Flange portion, 13A: Upper surface of flange portion, 15: Large projection, 17: Small projection, 27: Engaging convex portion, 29: Bolt-through hole in engaging convex portion, 33: Engaging recess, 34: Bolt-through hole in engaging recess, 35: Ground contact surface of cylindrical portion, 61: Shoe, 71: Vertical connecting member according to modified example, 73: Pile engagement ring

Claims

1. For simple stairs that can be installed on sloping ground, a plurality of beam members each forming a plurality of stages; a plurality of fixing piles for fixing the plurality of girder members to the sloping ground; Equipped with Each girder member has a horizontally long tubular portion that is installed horizontally on the sloping ground, The cylindrical portion is The top surface of each step corresponds to the part including the nosing; one or more main protrusions disposed on the upper surface and protruding upward; and The upper end surface of the main projection is inclined upward and forward in side view, and the front upper end of the main projection forms an acute angle in side view.

2. The simple staircase according to claim 1, The upper surface of the cylindrical portion is the highest peak between the rear end and the front end of the upper surface; an upwardly inclined surface inclined forward and upward from the rear end to the highest part; and The main protrusion is a simple staircase disposed on the upwardly inclined surface.

3. The simple staircase according to claim 2, A simple staircase in which the height of the front upper end of the main protrusion is higher than the highest part of the top surface of the cylindrical portion.

4. The simple staircase according to claim 1, Each of the main projections has a protruding height within the range of 10 mm to 20 mm.

5. The simple staircase according to claim 1, a plurality of the main protrusions are arranged laterally on the upper surface of the cylindrical portion; Each of the main projections extends laterally over a horizontal length in the range of 45 mm to 70 mm and is curved in a wavy shape in a plan view; A simple staircase in which there is a gap between adjacent main projections.

6. The simple staircase according to claim 5, A simple staircase in which the horizontal dimension of the gap is within the range of 10 mm to 35 mm.

7. The simple staircase according to claim 2, The upper surface of the cylindrical portion has a downwardly inclined surface that slopes downward from the highest point to the front end.

8. The simple staircase according to claim 7, Each of the beam members further includes a horizontally elongated flange portion extending forward from a front end portion of the cylindrical portion, an upper surface of the flange portion is lower than the upper surface of the cylindrical portion and is substantially horizontal; A simple staircase in which one or more auxiliary protrusions protruding upward are provided on the upper surface of the flange portion.

9. The simple staircase according to any one of claims 7 and 8, A simple staircase in which the front-to-rear dimension of the cylindrical portion is in the range of 70 mm to 80 mm.

10. The simple staircase according to claim 1, Each of the plurality of beam members has one lateral end wall and another lateral end wall, the one end wall having a protrusion and / or a first through hole, and the other end wall having a recess and / or a second through hole, A simple staircase configured so that the first and second beam members are connected laterally by engaging the convex portion of the first beam member with the convex portion of the second beam member and / or by fastening the one end wall and the other end wall to each other with fasteners inserted through the first and second through holes.

11. The beam member for a simple staircase according to any one of claims 1 to 8 and claim 10.