PREFABRICATED SPIRAL STAIRCASE

Abstract

The present invention relates to a prefabricated spiral staircase in which the heights between treads can be freely and finely adjusted, thus being conveniently assembled and installed at installation sites having different story heights.

Description

TECHNICAL FIELD

The present invention relates to a prefabricated spiral staircase in which the heights between treads can be freely and finely adjusted, thus being conveniently assembled and installed at installation sites having different story heights.

BACKGROUND ART

Staircases are divided into linear staircases and curved staircases.

Linear staircases have linear shapes, and refer to staircases having a ladder form.

Curved staircases are basically divided into spiral staircases with a center pole and double helical staircases without a center pole.

Spiral staircases can be assembled at installation sites in the manners described in patent documents 1 and 2, unlike double helical staircases.

As shown in FIGS. 1 and 2, the prefabricated spiral staircase 1 of patent document 1 includes: a post 2 configured to be placed upright and fastened via anchor bolts 3, and fabricated to have a height suitable for the height of a corresponding story; spacer-bushes 5 configured to be inserted over the post 2; treads 4 configured to be inserted over the post 2 alternately with the spacer-bushes 5; brackets 7 fastened to the treads 4 in an integrated manner, and configured to include coupling holes 6 adapted to be inserted over the post 2; and handrails 8 configured to be inserted into a plurality of coupling holes 9 formed at the outer ends of the treads 4, and each configured to be inserted into all the coupling holes 9 formed in vertically adjacent two of the treads 4. Of the treads 4, a fastening tread 4a configured to be installed at the uppermost end is fixedly installed on the slab 10 of a corresponding story or the like, and some of the coupling holes 9 configured to enable the handrails 8 to be coupled thereto are formed in the fastening tread 4a.

By the way, a story height, e.g., the height between a first floor and a second floor, at an installation site usually and slightly varies depending on the construction situation of a building or the like. For such a difference, in the case of the prefabricated spiral staircase 1 of patent document 1, the spacer-bushes 5 suitable for a story height must be prepared or the spacer-bushes 5 must be cut or attached through welding or the like at a site on each occasion, thereby making installation inefficient or causing material to be wasted.

Meanwhile, in patent document 1, the fastening treads 4a are more weakly supported than the fastening treads 4a supported by side plates because the fastening treads 4a are held by the handrails 8, i.e., stringers, composed of U-shaped rods.

Furthermore, the fastening treads 4a of patent document 1 are installed in such a way that they are inserted over the post 2, and thus the treads 4 are simply disposed stepwise. Accordingly, the treads 4 are unstably fastened, and may be shaken while a user is walking up and down the staircase.

The simple stepwise insertion and disposition and the support of treads using rods may provide a sensation of instability a user.

To remove this sensation of instability, patent document 2 discloses a prefabricated octagonal spiral staircase.

The prefabricated octagonal spiral staircase of patent document 2 is now described with reference to FIGS. 3 and 4. The prefabricated octagonal spiral staircase includes: a center pillar 16; outside stringer segments 10; and treads 20 installed between the center pillar 16 and the outside stringer segments 10.

• One side of each of the treads 20 is coupled to the center pillar 16, and the opposite side of each of the treads 20 is coupled to the side plate 11 of a corresponding one of the outside stringer segments 10.

However, in patent document 2, the prefabricated octagonal spiral staircase can be rarely installed unless the prefabricated octagonal spiral staircase is prepared for the dimensions determined through the sufficient understanding of the circumstances of an installation site.

In other words, the center pillar 16 is composed of eight segments 17, 18 and 19, and notches to which corresponding treads 20 are coupled and the number of which is equal to the number of corresponding treads 20 are formed in each of the segments.

Accordingly, story heights at all installation sites cannot be accommodated by the center pillar 16 in which the notches have been formed in advance, and thus assembly parts suitable for each installation site must be fabricated.

As described above, the staircases of patent documents 1 and 2 cannot be prefabricated for all installation sites and thus have poor versatility, with the result that the assembly and installation properties thereof are considerably degraded.

PRIOR ART DOCUMENTS

Patent Documents

(Patent document 1) Korean Patent Application Publication No. 10-2004-0101161

(Patent document 2) U.S. Pat. No. 5,737,884

DISCLOSURE

Technical Problem

The present invention has been conceived to overcome the above-described problems, and an object of the present invention is to provide a prefabricated spiral staircase which can improve versatility so that the prefabricated spiral staircase can be applied to any installation site even when story height varies, thereby considerably improving the assembly and installation properties thereof.

Technical Solution

In order to accomplish the above object, a prefabricated spiral staircase set forth in claim 1 of the present application includes: a base configured to be fastened to a floor; a center pole configured such that the lower end thereof is installed on the base; a plurality of spacers configured to be inserted over the center pole; treads each configured such that one side thereof is inserted over the center pole between corresponding adjacent two of the spacers; outside stringers each disposed on the opposite side of the tread; and coupling members each configured to couple the opposite side of the tread to the outside stringer; wherein each of the spacers includes a cylindrical pipe, and a lower or upper cap configured to be inserted over the lower or upper side of the cylindrical pipe.

In the prefabricated spiral staircase set forth in claim 2 of the present application, one or more height adjustment disks are further disposed internally between the lower cap and the lower end of the cylindrical pipe or between the upper cap and the upper end of the cylindrical pipe.

In the prefabricated spiral staircase set forth in claim 3 of the present application, the center pole is a male threaded pole, and nuts are each engaged with the center pole so that the lower cap applies pressure to the one side of the tread.

In the prefabricated spiral staircase set forth in claim 4 of the present application, the outside stringers are configured such that at least a plurality of linear side plates is assembly together and form a rectangular shape when viewed in a plan view.

In the prefabricated spiral staircase set forth in claim 5 of the present application, each of the coupling members includes: a bracket configured to be disposed in a recession formed by cutting out a portion of the opposite side of the tread; first fastening metal elements configured to insert and fasten the bracket into the opposite side of the tread; and second fastening metal elements configured to insert and fasten the bracket into the inner surface of a corresponding one of the linear side plates.

In the prefabricated spiral staircase set forth in claim 6 of the present application, each of the brackets includes: a bracket body configured to have an outer surface adapted to come into contact with the inner surface of the linear side plate and an inner surface adapted to come into contact with a side surface of the tread; first through holes configured to penetrate through the inner and outer surfaces of the bracket body, and to be supported by the first fastening metal elements; and second through holes configured to penetrate through the top surface of the bracket body and the outer surface of the bracket body or through the bottom surface of the bracket body and the outer surface of the bracket body, and to be supported by the second fastening metal elements.

A spacer coupling structure for a prefabricated spiral staircase set forth in claim 7 of the present application includes a center pole configured to be fastened to a floor; a plurality of spacers configured to be inserted over the center pole; and treads each configured such that one side thereof is inserted over the center pole between corresponding adjacent two of the spacers; wherein each of the spacers comprises a cylindrical pipe, and a lower or upper cap configured to be inserted over the lower or upper side of the cylindrical pipe.

Advantageous Effects

According to the present invention, the following effects are achieved.

The height of each of the spacers can be adjusted by selectively inserting and removing a corresponding upper or lower cap over and from the cylindrical pipe, and thus assembly and installation can be easily performed even when story height varies depending on an installation site.

One or more disks are disposed internally between the upper cap and the cylindrical pipe or between the lower cap and the cylindrical pipe, and thus the range of differences in story height can be more rapidly dealt with. Furthermore, the disks are disposed in the inside, and thus a neat appearance can be provided, thereby enabling the present invention to be considerably useful for indoor application.

The nuts are engaged with the male threaded center pole, and thus the lower cap applies pressure to one side of a corresponding tread, thereby firmly supporting the tread and enabling the staircase to be stably used.

The outside stringers are configured such that at least a plurality of linear side plates are coupled to one another and form rectangular outside stringers when viewed in a plan view, and thus the rectangular outside stringers have more desirable spatial efficiency than arc-shaped outside stringers. In other words, in the case where three surfaces are walls, the corners of the rectangular outside stringers form a right angle, and thus a wasted space can be removed, thereby providing significantly desirable spatial efficiency.

Each of brackets is disposed in a corresponding recession formed through a side surface of a corresponding one of the treads, is fastened to the corresponding tread, and then is fastened to a corresponding side plate. Accordingly, a separate recession or the like does not need to be formed in the side plate, thereby being considerably useful for the fabrication of a prefabricated staircase. Furthermore, a stable staircase can be constructed due to high torsional resistance.

In particular, the fastening of the brackets to the side plates is performed in inclined directions, and thus the support of the treads for the side plates becomes more firm.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a conventional prefabricated spiral staircase;

FIG. 2 is an exploded perspective view showing the essential part of FIG. 1;

FIG. 3 is a perspective view showing another conventional prefabricated spiral staircase;

FIG. 4 is a schematic plan view of FIG. 3;

FIG. 5 is a perspective view showing a prefabricated spiral staircase according to a preferred embodiment of the present invention;

FIG. 6 is a plan view of FIG. 5;

FIGS. 7 to 11 are perspective views showing the installation of a center pole on a base;

FIGS. 12 to 14 are perspective views showing the installation of the lowermost spacer;

FIG. 15 a sectional view taken along line 15-15 of FIG. 14;

FIGS. 16 to 20 are perspective views showing the steps of the assembly of treads and a first outside stringer segment.

FIG. 21 is a sectional view showing the coupling of a spacer according to a preferred embodiment of the present invention;

FIG. 22 is a sectional view showing the coupling of a tread and a side plate according to a preferred embodiment of the present invention;

FIGS. 23 and 24 are perspective views showing a bracket according to a preferred embodiment of the present invention when viewed from an outside and an inside; and

FIG. 25 is a perspective view showing the installation state of a staircase after poles have been connected to each other.

MODE FOR INVENTION

Preferred embodiments of the present invention will be described with reference to the accompanying drawings below.

Referring to FIGS. 5 and 25, a prefabricated spiral staircase 100 according to a preferred embodiment of the present invention includes: a base 200 configured to be fastened to a floor FL; a center pole 300 configured such that the lower side thereof is installed on the base 200; a plurality of spacers 400 configured to be inserted over the center pole 300; treads 500 each configured such that the inner side thereof is inserted over a portion of the center pole 300 between corresponding adjacent two of the spacers 400; outside stringers 600a to 600d configured to be disposed on the outer sides of the treads 500; and coupling members 900 configured to couple the outer sides of the treads 500 to the outside stringers 600a to 600d.

As shown in FIG. 8, the base 200 includes a first base 210 configured to be fastened to the floor FL, and a second base 260 configured to be coupled to the first base 210 and support the lower portion of the center pole 300.

As shown in FIG. 7, the first base 210 is formed in a disk shape, and an insertion hole 211 configured to receive the lower end side of the center pole 300 is formed at the center of the first base 210.

Furthermore, first through holes 213 are formed along the edge of the first base 210.

First fasteners 215 or the like are inserted into and caught in the floor FL through the first through holes 213, thereby pressing and fastening the first base 210 into the floor FL.

Furthermore, a plurality of first female threaded holes 217 is formed around the insertion hole 211 of the first base 210.

The second base 260 configured to hold the lower side of the center pole 300 is engaged with and fastened to the plurality of first female threaded holes 217.

As shown in FIG. 8, the second base 260 is formed in a cylindrical shape, and a second female threaded hole 261 configured to be engaged with the center pole 300 is formed at the center of the second base 260.

The second female threaded hole 261 is disposed at a location corresponding to that of the insertion hole 211.

A plurality of second through holes 265 configured such that bolts, i.e., second fasteners 263 configured to be engaged with the plurality of first female threaded holes 217, are disposed therein is formed in the second base 260.

The second fasteners 263 are engaged with and caught in the first female threaded holes 217 though the second through holes 265, as through the first through holes 213, thereby pressing and fastening the second base 260 into the first base 210.

The center pole 300 is a male threaded pole. As shown in FIG. 15, the center pole 300 is engaged with the second female threaded hole 261 of the second base 260. The lower end 301 of the center pole 300 is moved downward through the insertion hole 211 of the first base 210 until the lower end 301 comes into contact with and is stopped by the floor FL.

When the center pole 300 has been engaged with the second female threaded hole 261, it is preferred that a loosening prevention nut 310, such as that of FIG. 10, is engaged with the center pole 300 and pushes the top surface of the second base 260 so as to prevent the second base 260 from being loosened due to bolt loosening or the like.

In particular, it is preferred that the loosening prevention nut 310 is implemented using a washer-based nut.

The height of the center pole 300 may be adjusted based on the height of a corresponding story by connecting such center poles 300.

In other words, as shown in FIG. 25, the center poles 300, i.e., male threaded poles, may be coupled to each other via a nut 330 similar to a turnbuckle.

Each of the spacers 400 includes a cylindrical pipe 410, a lower cap 430 configured to be inserted over the lower side of the cylindrical pipe 410, and an upper cap 450 configured to be inserted over the upper side of the cylindrical pipe 410.

The cylindrical pipe 410 is formed in a cylindrical shape. It is preferred that the height of the cylindrical pipe 410 is slightly smaller than the ordinary height between the treads 500. The reason for this is that the height of the cylindrical pipe 410 is considerably useful to selectively increase and decrease the height between the treads 500 at an installation site.

Each of the lower and upper caps 430 and 450 includes a horizontal plates 431 or 451 configured to cover the lower surface of the cylindrical pipe 410, and a vertical wall 433 or 453 configured to protrude from the edge of the horizontal plate 431 or 451 so as to be inserted over the outer surface of the cylindrical pipe 410. It will be apparent that through holes 435 and 455 configured to be inserted over the center pole 300 are formed at the centers of the horizontal plates 431 and 451, respectively.

Accordingly, the height is increased by the thickness of the horizontal plate 431 of the lower cap 430 when the lower cap 430 is inserted over the cylindrical pipe 410, and is increased by twice the above thickness when the lower and upper caps 430 and 450 are inserted over the cylindrical pipe 410.

In particular, it is preferred that height adjustment disks 440 and 460 are further disposed in the corresponding spacer 400.

In other words, when the height adjustment disks 440 and 460 are inserted into an inside between the lower cap 430 and the lower end 411 of the cylindrical pipe 410 or into an inside between the upper cap 450 and the upper end 413 of the cylindrical pipe 410, the intervals between the treads 500 can be finely adjusted.

It is preferred that a plurality of thin ring-shaped disks is prepared as the disks 440 and 460 and a required number of thin ring-shaped disks are used.

In the present embodiment, each of the lower disk 440 and the upper disk 460 is implemented using two disks 441 and 443 or 461 and 463.

As described above, in the present embodiment, the height of the spacer 400 can be variously and finely adjusted through the insertion or removal of the disks 440 and 460 as well as the upper and lower caps 450 and 430, and thus the treads 500 can be easily assembled and installed at predetermined intervals even when the height of a story varies depending on each installation site.

Accordingly, once the spacers 400 according to the present embodiment have been prepared, installation can be rapidly and accurately performed at any installation site without an effort to produce or machine a separate part so as to adjust the height.

In this case, since the lower cap 430a of the lowest one 400a of the plurality of spacers 400 needs to be inserted over the outer circumferential surface of the second base 260, as shown in FIGS. 11 and 15, a through hole 435a larger than the through holes 435 of the spacers 400 above the lowest spacer 400a is formed.

The reference symbols of the respective parts of the lowest or starting spacer 400a are merely made distinct by adding the lowercase character “a” to the corresponding reference symbols of the other spacers 400, and the functions of the corresponding parts are identical.

Furthermore, as shown in FIG. 21, it is preferred that the disks 440 and 460 are coupled and supported inside the upper and lower caps 450 and 430 via screws 445 and 465.

As shown in FIGS. 12 and 15, it is preferred that accommodation holes 447 and 467 configured to accommodate portions of the screws 445 and 465 are formed in the inner circumferential surfaces of the disks 440 and 460, and female threads 446 and 466 are preferably formed in the upper and lower caps 450 and 430 so that the female threads 446 and 466 correspond to the accommodation holes 447 and 467.

It is preferred that short or long screws are prepared as the screws 445 and 465 depending on the heights of the disks 440 and 460. The reason for this is to prevent the screws 445 and 465 from protruding above the upper and lower horizontal plates 431 and 451 when the screws 445 and 465 have engaged with the female threads 446 and 466.

As shown in FIG. 17, once the first spacer 400a has been installed, one side of a first tread 500 is inserted over the center pole 300 and disposed on the top surface of an upper cap 450a, the corresponding lower cap 430 of a second spacer 400 is inserted over the center pole 300, and then a pressure nut 700 is engaged with the center pole 300 and applies pressure to the lower cap 430, as in the case of the first spacer 400a. Then the lower cap 430 pushes and stably supports the one side of the tread 500.

As described above, when the spacers 400 are assembled, a number of pressure nuts 700 equal to the number of spacers are engaged, and thus each of the treads 500 is firmly supported without shaking.

Protrusions 437 and 457 are formed at the centers of the top surface of the lower cap 430 and the bottom surface of the upper cap 450, respectively.

Of the protrusions 437 and 457, the protrusion 437 used for the lower cap 430 functions as a mounting surface configured such that a corresponding one of the pressure nuts 700 is mounted thereon, and also functions as a reinforcement member configured to prevent damage from being caused even when the pressure nut 700 is strongly tightened because the thickness of the protrusion 437 is considerably thicker than that of the horizontal plate 431.

For reference, only the through hole 435a is disposed in the horizontal plate 431a of the lower cap 430a of the lowest spacer 400a.

As shown in FIGS. 16 to 20, each of the treads 500 is a plate formed in a shape similar to a fan shape (because the treads are disposed stepwise to form a spiral shape), a through hole 510 configured to be inserted over the center pole 300 is formed in one (inner) side of the tread 500, and recessions 510 each formed by cutting out a portion of the tread 500 in a left square bracket shape are formed in the opposite (outer) side of the tread 500.

Furthermore, as shown in FIG. 19, a recession 530 or 550 formed by cutting out a portion of a corresponding tread 500 in an “L” shape fitting a newel 630a or 650a may be further formed in the opposite (outer) side of the tread 500 depending on the location of the tread 500.

It is preferred that protrusions 439 and 459 configured to be inserted into the through hole 510 are formed at the centers of the upper and lower caps 450 and 430 so as to prevent the through hole 510 of the tread 500 from shaking when disposed between the upper cap 450 on the lower side thereof and the lower cap 430 on the upper side thereof.

The recessions 510 are composed of recessions in a shape the upper, lower and outer sides of which are open.

Brackets 910 which will be described later are disposed in the recessions 510.

As shown in FIGS. 5 and 6, outside stringers 600a to 600d are formed in a rectangular shape when viewed in a plan view, and include: a first outside stringer segment 600a, i.e., a starting point; a second outside stringer segment 600b configured to be connected to the first outside stringer segment 600a; a third outside stringer segment 600c configured to be connected to the second outside stringer segment 600b; and a fourth outside stringer segment 600d, i.e., an ending point, configured to be connected to the third outside stringer segment 600c.

The first outside stringer segment 600a includes: a first linear side plate 610a; a first linear handrail 620a; first upper and lower newels 630a and 640a configured to be coupled to the upper and lower ends of the first linear side plate 610a and the upper and lower ends of the first linear handrail 620a; and first balusters 650a configured to be disposed between the top surface of the first linear side plate 610a and the bottom surface of the first linear handrail 620a.

The second outside stringer segment 600b is coupled to the first outside stringer segment 600a at a right angle, and includes: a second linear side plate 610b configured such that the lower end thereof is coupled to the first upper newel 630a; a second linear handrail 620b configured such that the lower end thereof is coupled to the first upper newel 630a; a second newel 630b configured to be coupled to the upper ends of the second linear side plate 610b and the second linear handrail 620b; and second balusters 650b configured to be disposed between the top surface of the second linear side plate 610b and the bottom surface of the second linear handrail 620b.

The third outside stringer segment 600c is coupled to the second outside stringer segment 600b at a right angle, and includes: a third linear side plate 610c configured such that the lower end thereof is coupled to the second upper newel 630b; a third linear handrail 620c configured such that the lower end thereof is coupled to the second upper newel 630b; a third newel 630c configured to be coupled to the upper ends of the third linear side plate 610c and the third linear handrail 620c; and third balusters 650c configured to be disposed between the top surface of the third linear side plate 610c and the bottom surface of the third linear handrail 620c.

The fourth outside stringer segment 600d, i.e., an ending point, is coupled to the third outside stringer segment 600c at a right angle, and includes: a fourth linear side plate 610d configured such that the lower end thereof is coupled to the third newel 630c; a fourth linear handrail 620d configured such that the lower end thereof is coupled to the third newel 630c; a fourth newel 630d configured to be coupled to the upper ends of the fourth linear side plate 610d and the fourth linear handrail 620d; and fourth balusters 650d configured to be disposed between the top surface of the fourth linear side plate 610d and the bottom surface of the fourth linear handrail 620d.

A 4′-th inside stringer segment 600d′ facing the fourth outside stringer segment 600d is installed.

The 4′-th inside stringer segment 600d′ includes: a 4′-th newel 630d′ configured to correspond to the fourth newel 630d; a 4″-th newel 630d″ configured to be fastened to the uppermost end of the center pole 300; a 4′-th handrail 620d′ configured to be coupled to the 4′-th newel 630d′ and the 4″-th newel 630d″; and 4′-th balusters 650d′ configured to be disposed between the top surface of the last tread 500b and the bottom surface of the 4′-th handrail 620d′.

It is preferred that at least the first upper newel 630a, the first lower newel 640a, and the second newel 630b are disposed on the floor and function as pillars.

The fourth newel 630d and the 4′-th newel 630d′ are fastened to the wall of the slab of a second floor or the like.

Each of the first to fourth linear side plates 610a to 610d and the first to fourth linear handrails 620a to 620d includes an inclined linear plate inclined from the lower end thereof toward the upper end thereof.

Each of the first to fourth linear side plates 610a to 610d is formed in a plate shape in which the height thereof is larger than a thickness between an outer surface 1a thereof and an inner surface 1b thereof, and each of the first to fourth linear handrails 620a to 620d is formed in a plate shape in which the height thereof is smaller than that of the corresponding one of the first to fourth linear side plates 610a to 610d.

Furthermore, it is preferred that machining is performed such that the upper and lower sides thereof are parallel or approximately parallel to the horizontal direction so as to deal with the height differences between the outside stringer segments 600a to 600d.

In other words, as shown in FIG. 20, the first linear side plate 610a includes: an inclined linear plate 611a; and upper and lower horizontal plates 613a and 615a disposed on the upper and lower sides of the inclined linear plate 611a.

In the same manner, the first linear handrail 620a includes an inclined linear plate 621a and upper and lower horizontal plates 623a and 625a in a form identical to that of the first linear side plate 610a.

Accordingly, each of the opposite second to fourth linear side plates 610b to 610d includes: an inclined linear plate; and upper and lower horizontal plates disposed on the upper and lower sides of the inclined linear plate.

Furthermore, each of the second to fourth linear handrails 620b to 620d includes an inclined linear plate and upper and lower horizontal plates in a form identical to that of each of the second to fourth linear side plates 610b to 610d.

Since the upper and lower horizontal plates are disposed, the height differences between segments in upward and downward directions are prevented during the assembly of the segments, and thus the segments seem to be continuously connected to one another in their appearance.

Although it is preferred that the handrails are formed in a bar shape rather than a plate shape, it is preferred that the handrails are formed in a plate shape because there occurs the inconvenience in which separate bars need to be connected so as to prevent height differences.

As shown in FIG. 22, each of the coupling members 900 includes: a bracket 910 disposed in a corresponding one of the recessions 510 of the treads 500; first fastening metal elements 930 configured to insert and fasten the bracket 910 into a corresponding one of the treads 500; and second fastening metal elements 950 configured to insert and fasten the bracket 910 into an inner surface of a corresponding one of the linear side plates 610.

As shown in FIGS. 23 and 24, the bracket 910 includes: a bracket body 911; first through holes 913 configured to penetrate through the outer and inner surfaces 911a and 911b of the bracket body 911; and second through holes 915 or 917 configured to penetrate through the top and outer surfaces 911c and 911a of the bracket body 911 or through the bottom and outer surfaces 911d and 911a of the bracket body 911.

The first through holes 913 are horizontal through holes configured to penetrate through two surfaces, i.e., the inner and outer surfaces 911b and 911a, which are spaced apart from each other.

The second through holes 915 or 917 are divided into 2a-th through holes 915 and 2b-th through holes 917 according to the present embodiment and then described below.

In other words, the 2a-th through holes 915 are through holes configured to penetrate through two adjacent surfaces, i.e., the top and outer surfaces 911c and 911a, of the bracket body 911.

Furthermore, the 2b-th through holes 917 are through holes configured to penetrate through two adjacent surfaces, i.e., the bottom and outer surfaces 911d and 911a, of the bracket body 911.

In the same manner, the second fastening metal elements 950 are divided into 2a-th fastening metal elements 950a and 2b-th fastening metal elements 950b and then described.

It is preferred that the bracket body 911 is formed in a hexahedron shape having front and rear surfaces 911e and 911f, the inner and outer surfaces 911b and 911a, and the top and bottom surfaces 911c and 911d.

When the bracket body 911 is formed in a hexahedron shape, the 2a-th through holes 915 correspond to 2a-th inclined through holes 915 having a positive slope from a top (i.e., the top surface) to a bottom (i.e., the outer surface), and the 2b-th through holes 917 correspond to 2b-th inclined through holes 917 having a negative slope from a bottom (i.e., the bottom surface) to a top (i.e., the outer surface).

The plurality of first through holes 913 (which is three in number in the present embodiment) is disposed in a direction from a front side to a rear side. The number of first through holes 9130 is determined based on the specifications of a staircase.

The first fastening metal elements 930, such as nails or screws, are inserted into the first through holes 913 and fastened to a side of the tread 500, and thus the first fastening metal elements 930 function to fasten the bracket body 911 to the tread 500.

The 2a-th inclined through holes 915 are disposed above locations between the first through holes 913, and the 2b-th through holes 917 are disposed immediately below the first through holes 913.

The 2a-th and 2b-th fastening metal elements 950a and 950b, such as nails or screws, are inserted into the 2a-th and 2b-th inclined through holes 915 and 917 and fastened to the inner surface 1b of the side plate 610, and thus the 2a-th and 2b-th fastening metal elements 950a and 950b function to fasten the bracket body 911 to the side plate 610.

In particular, the 2a-th and 2b-th fastening metal elements 950a and 950b are fastened in inclined directions, and thus provide stronger resistance against load or torsion than the 2a-th and 2b-th fastening metal elements 950a and 950b fastened in horizontal directions, thereby increasingly ensuring safety.

Stop protrusions configured to stop the head portions of nails or screws are formed inside the first through holes 913 and the 2a-th and 2b-th inclined through holes 915 and 917.

Meanwhile, it is preferred that a flange 960 is further formed around the front, rear, and inner edges of the bottom surface 911d of the bracket body 911.

The flange 960 supports lower end edges of the recession 510 of the tread 500, thereby sustaining larger load.

In particular, when the flange 960 is disposed in a stepped groove 515 formed around the recession 510, the flange 960 is disposed in the same plane in which the bottom surface of the tread 500 is disposed, thereby providing a desirable appearance.

Furthermore, it is preferred that a downwardly extended portion 970 configured to extend downward is further formed on an outer side of the bottom surface 911d of the bracket body 911.

Third through holes 981 configured such that third fastening metal elements 980, such as nails, screws, or the like, are coupled through the third through holes 981 are further formed in the downwardly extended portion 970.

Stop protrusions configured to stop the head portions of the third fastening metal elements 980 are formed inside the third through holes 981.

The downwardly extended portion 970 comes into tight contact with the inner surface 1b of the side plate 610 and is fastened to the inner surface 1b of the side plate 610 via the third through holes 981, thereby sustaining considerably large load.

It is preferred that finishing plates (not shown) having a color identical to that of the tread 500 are attached to the top and bottom surfaces 911c and 911d of the bracket 910 via adhesive, magnets, screws, or the like.

When the finishing plate are fastened via screws, it is preferred that female threads are formed on the top surface 911c of the bracket 910 and the front and rear surfaces of the flange 960.

As described above, although the present invention has been described with reference to the preferred embodiments of the present invention, it will be apparent to those skilled in the art that the present invention may be changed or modified and then practiced in various manners without departing from the spirit and scope of the present invention set forth in the attached claims.

For example, although the outside stringers have been described as including the side plates, the handrails, the newels, and the balusters in a broad sense in the detailed description of the present embodiment, it will be apparent that the outside stringers may include only side plates and may form a spiral staircase in a narrow sense, which is applied to the present embodiment without change.

DESCRIPTION OF REFERENCE SYMBOLS

100: prefabricated spiral staircase

210 and 260: first and second bases

300: center pole

400: spacer

410: cylindrical pipe

450 and 430: upper and lower caps

440 and 460: disks

500: treads

600a to 600d: outside stringers

610a to 610: linear side plates

620a to 620d: linear handrails

630a to 630d: newels

650a to 650d: balusters

700: (pressure) nuts

900: coupling members

910: bracket

911: bracket bodies

913: first through holes

915 and 917: second inclined through holes

930: first fastening metal elements

950: second fastening metal elements

960: flanges

970: downwardly extended portions

980: third fastening metal elements

984: third inclined through holes

Claims

1. A prefabricated spiral staircase, comprising:

a base configured to be fastened to a floor;

a center pole configured such that a lower end thereof is installed on the base;

a plurality of spacers configured to be inserted over the center pole;

treads each configured such that one side thereof is inserted over the center pole between corresponding adjacent two of the spacers;

outside stringers each disposed on an opposite side of the tread; and

coupling members each configured to couple the opposite side of the tread to the outside stringer;

wherein each of the spacers comprises a cylindrical pipe, and a lower or upper cap configured to be inserted over a lower or upper side of the cylindrical pipe; and

wherein one or more height adjustment disks are further disposed internally between the lower cap and a lower end of the cylindrical pipe or between the upper cap and an upper end of the cylindrical pipe.

2. The prefabricated spiral staircase of claim 1 wherein the center pole is a male threaded pole, and nuts are each engaged with the center pole so that the lower cap applies pressure to the one side of the tread.

3. The prefabricated spiral staircase of claim 1 wherein the outside stringers are configured such that at least a plurality of linear side plates is assembled together and form a rectangular shape when viewed in a plan view.

4. The prefabricated spiral staircase of claim 3 wherein each of the coupling members comprises: a bracket configured to be disposed in a recession formed by cutting out a portion of the opposite side of the tread; first fastening metal elements configured to insert and fasten the bracket into the opposite side of the tread; and second fastening metal elements configured to insert and fasten the bracket into an inner surface of a corresponding one of the linear side plates.

5. The prefabricated spiral staircase of claim 4 wherein each of the brackets comprises: a bracket body configured to have an outer surface adapted to come into contact with the inner surface of the linear side plate and an inner surface adapted to come into contact with a side surface of the tread; first through holes configured to penetrate through the inner and outer surfaces of the bracket body, and to be supported by the first fastening metal elements; and second through holes configured to penetrate through a top surface of the bracket body and the outer surface of the bracket body or through a bottom surface of the bracket body and the outer surface of the bracket body, and to be supported by the second fastening metal elements.

6. A spacer coupling structure for a prefabricated spiral staircase, comprising:

a center pole configured to be fastened to a floor;

a plurality of spacers configured to be inserted over the center pole; and

treads each configured such that one side thereof is inserted over the center pole between corresponding adjacent two of the spacers;

wherein each of the spacers comprises a cylindrical pipe, and a lower or upper cap configured to be inserted over a lower or upper side of the cylindrical pipe; and

wherein one or more height adjustment disks are further disposed internally between the lower cap and a lower end of the cylindrical pipe or between the upper cap and an upper end of the cylindrical pipe.

7. The prefabricated spiral staircase of claim 2 wherein the outside stringers are configured such that at least a plurality of linear side plates is assembled together and form a rectangular shape when viewed in a plan view.

8. The prefabricated spiral staircase of claim 7 wherein each of the coupling members comprises: a bracket configured to be disposed in a recession formed by cutting out a portion of the opposite side of the tread; first fastening metal elements configured to insert and fasten the bracket into the opposite side of the tread; and second fastening metal elements configured to insert and fasten the bracket into an inner surface of a corresponding one of the linear side plates.

9. The prefabricated spiral staircase of claim 8 wherein each of the brackets comprises: a bracket body configured to have an outer surface adapted to come into contact with the inner surface of the linear side plate and an inner surface adapted to come into contact with a side surface of the tread; first through holes configured to penetrate through the inner and outer surfaces of the bracket body, and to be supported by the first fastening metal elements; and second through holes configured to penetrate through a top surface of the bracket body and the outer surface of the bracket body or through a bottom surface of the bracket body and the outer surface of the bracket body, and to be supported by the second fastening metal elements.