MODULE SYSTEM

FIELD OF THE INVENTION The present invention relates to the field of staircases and a method of mounting a staircase.

BACKGROUND OF THE INVENTION

Staircases generally consist of a pair of strings and multiple treads arranged between the strings at a fixed distance along the longitudinal extension of the strings. Due to the different spaces into which staircases are to be mounted, the dimensions and slope of the staircase may vary greatly and therefore, staircases are most often produced individually for each customer or in small production series for groups of identical houses. As a consequence, staircases can seldom be pre-fabricated and stored but are instead produced upon order, for which the delivery times are long.

In the case of outdoor staircases, these are often constructed in place in order to adapt to the ground conditions of the installation site. This is a time-consuming and therefore costly process.

To allow the installation of staircases of different angles with the same pair of strings, strings with adjustable treads or tread supports have been developed. JP2006328775 discloses such a staircase assembly, comprising angle adjustable tread support members spaced in the longitudinal extension of a string. The tread supports are turnably mounted at each string and can therefore be fixed in different positions based on the slope of the staircase. A problem with this kind of staircase assembly is that it requires numerous operations for mounting the tread supports to a correct angle.

SUMMARY OF THE INVENTION

It would be advantageous to simplify the mounting process of staircases and to provide a staircase which can be pre-fabricated. To better address this concern, in a first aspect of the invention there is provided a string assembly for a staircase comprising a string and multiple tread supports, the tread supports having a support surface for supporting a tread. Each tread support is pivotally arranged at a fixed relative distance along the longitudinal extension of the string. The string assembly further comprises a first side element and a second side element, arranged in parallel, and the tread supports are pivotally arranged between the first side element and the second side element. Each tread support is pivotally moveable at least between a retracted position, in which the tread support does not protrude from the side elements of the string, and a mounting position, in which the support surface of the tread support is arranged horizontally. One of the first side element and the second side element further comprises a set of fixing members at a fixed relative distance along the longitudinal extension of the string and at a portion of said side element that covers the tread support when in a mounting position, so arranged for fixing the mounting position of each tread support.

The string assembly can be pre-fabricated and is adjustable to any site at which a staircase is to be installed by cutting the length and end angles of the side elements accordingly. The pivotal arrangement of the tread supports further enables adjusting the tread supports to a horizontal position

independently of the slope with which the staircase is mounted. Having the tread supports pivotally arranged between the first side element and the second side element of the string further allows packaging the string assembly in a compact manner, without any parts protruding from the side elements. When the string assembly is to be packaged and delivered to the installation site of the staircase, the tread supports are arranged in the retracted position, providing for an easy handling of the string assembly.

The fixing members provide an easy way of fixing the tread supports in a mounting position. The fixing members can furthermore be provided at the inner side element such that the surface of the outer side element is clean.

In accordance with an embodiment of the string assembly, the width of the first side element and the second side element of the string is at least as large as the height of the tread supports. This enables arranging the tread supports such that they do not protrude from the side elements of the string.

In accordance with an embodiment of the string assembly, each of the first side element and the second side element, at least at facing sides, is provided with a set of engagement members at a fixed relative distance along the longitudinal extension of the string, for pivotal engagement with the tread supports. The engagement portions being arranged at facing sides of the side elements of the string assembly, provide a visual advantage as the outer surface of at least the outer side element of the string assembly is clean.

In accordance with an embodiment of the string assembly, the string further comprises a holding member extending between the first side element and the second side element at a portion not covering the tread supports. The holding member, extending between the two side elements, provides stability to the string. Furthermore, when the tread supports are in the retracted position, the holding member can be adjusted such to prevent a pivotal movement of the tread supports towards a mounting position. This is particularly advantageous during transportation of the string assembly, as it reduces the risk of damaging the tread supports during this stage. In line with the inventive concept, more than one holding member can be provided at the string.

In accordance with an embodiment of the string assembly, each tread support further comprises an adjusting portion at a fixed distance from the support surface of the tread support, arranged for, during mounting, adjusting the pivotal angle of the tread support into said mounting position. The string assembly further comprises an adjusting tool comprising a first end and a second end, the first end having a first engagement member for engagement with the adjusting portion of one of the tread supports, and the second end having a second engagement member for engagement with the adjusting portion of an adjacent tread support. The first and the second engagement members of the adjusting tool are arranged at a predetermined distance corresponding to the distance between the adjusting portions of two adjacent tread supports in the mounting position. The adjusting tool provides an efficient aid for mounting the tread support in a mounting position, and locking the tread support therein while the tread support is being fixed in the mounting position. When a first tread support is mounted in a predetermined position, the adjacent tread support is adjusted into its mounting position by engagement of the first engagement member of the adjusting tool with the adjusting portion of the already mounted tread support, and by engagement of the second engagement member of the adjusting tool with the adjusting portion of the adjacent tread support. When the adjusting tool is engaged at both ends, and the support surface of the tread support is horizontal, the tread support can be fixed in the mounting position.

In accordance with an embodiment of the string assembly, the adjusting portion of the tread supports comprises a hole, a non-through hole, a hook, a protruding pin or similar. The outer surface of the tread support can be held clean when the adjusting portion, comprising a non-through hole, a hook, a protruding pin or similar, is provided on the inner surface of the tread support.

In accordance with an embodiment of the string assembly, the first and the second engagement members of the adjusting tool comprise protruding pins, or holes or similar, arranged to engage with the adjusting portions of the tread supports. These provide easy ways of engaging the adjusting tool with adjusting portions of the tread supports.

According to a second aspect of the invention, there is provided a staircase module system comprising a pair of string assemblies, and further comprising treads for, in a mounting position, being arranged at the support surface of each parallel pair of tread supports and fixed thereat. When a staircase is ordered, based on the dimension of the site at which the staircase is to be installed, the length and end angle of the string assemblies are cut accordingly. The string assemblies and the treads can then be packaged in a compact layer and delivered to the site of installation in a short time.

According to a third aspect of the invention, there is provided a method of mounting a staircase module system comprising the steps of adjusting the length and end angle of the pair of string assemblies according to the space available for the staircase, fixing the upper end and the lower end of each string assembly to an upper and a lower anchoring point respectively. The method further comprises the steps of pivoting the first tread support from the lower end of each of the string assemblies to a mounting position and fixing said tread supports by means of the corresponding fixing member of one of the first side element and the second side element of each string assembly. Thereafter, according to the method, the adjacent tread supports are pivoted and fixed, one by one, by means of the corresponding fixing member of one of the first side element and the second side element of each string assembly. A final step of the method comprises mounting and fixing a tread on each parallel pair of tread supports.

According to another embodiment for mounting a staircase module system, there is provided a method comprising the steps of adjusting the length and end angle of the pair of string assemblies according to the space available for the staircase, fixing the upper end and the lower end of each string assembly to an upper and a lower anchoring point respectively. The method further comprises the steps of pivoting the first tread support from the lower end of each of the string assemblies to a mounting position and fixing said tread supports by means of the corresponding fixing member of one of the first side element and the second side element of each string assembly. The method thereafter comprises pivoting and locking the adjacent tread support by means of the adjusting tool, in a mounting position and fixing said adjacent tread support by the corresponding fixing member, and pivoting and locking the following tread supports, one by one, in a mounted position by means of the adjusting tool and fixing said tread supports by the

corresponding fixing members. Finally, a last step comprises mounting and fixing a tread on each parallel pair of tread supports. Applying this method for mounting stairs only requires a normal screw driver and a spirit level or the like as complementary tools. It is therefore an efficient way of mounting a staircase, both in terms of time and of work effort. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail and with reference to the appended drawings in which:

Fig. 1 is a perspective inner side view of an embodiment of the string assembly according to the present invention;

Fig. 2 is a perspective outer side view of an embodiment of the string assembly according to the present invention;

Fig. 3 is a perspective inner side view of two tread supports and an adjusting tool used to mount the string assembly according to a method of the present invention; and

Fig. 4 is a perspective inner side view of an embodiment of the string assembly in a retracted position according to the present invention.

DESCRIPTION OF EMBODIMENTS

In the figures, like numbers represent like elements.

Referring to Fig. 1 , there is provided a string assembly 100 with a string comprising a first side element 1 and a second side element 2. The first side element 1 and the second side element 2 are arranged in parallel and at a distance from each other. Each side element 1 , 2 is elongated and has a rectangular cross-section. In the exemplifying embodiment of Fig. 1 , a width w and thickness t of the side elements 1 , 2 are defined, the width being larger than the thickness. The width, w, is at least as large as the height, h, (see Fig. 3 of the tread supports 3), which are pivotally arranged between the first side element 1 and the second side element 2. The axis of the pivotal

arrangement is perpendicular to the side elements 1 , 2, such that the tread supports 3 can pivot in a plane which is parallel to the longitudinal extension of the string.

The string assembly 100 further comprises multiple tread supports 3, pivotally arranged between the first side element 1 and the second side element 2 at a fixed relative distance along the longitudinal extension of the string. The tread supports 3 comprise a support surface 31 , arranged to support a tread of a staircase. The tread supports 3 are generally rectangular or square and have a rounded lower edge. The rounded lower edge enables pivoting one tread support 3 without interfering with an adjacent tread support. The height, h, of the tread supports 3 is preferably close to the width, w, of the side elements 1 , 2. This provides flexibility of the string assembly in terms of pivotal positioning of the tread supports 3. Other applicable shapes of the tread support 3 are also possible within the inventive concept.

The tread supports are distributed along the side elements 1 ,2 at a distance allowing each tread support 3 to be pivotally moveable between a retracted position and a mounting position. In the retracted position, the complete tread support 3 is arranged between the first side element 1 and the second side element 2 (see Fig. 4). In this retracted position, it does not protrude from the side elements 1 ,2 of the string. Furthermore, in the mounting position, the tread support 3 is pivoted upwards until the support surface 31 is horizontal. In the exemplifying embodiment of Figs. 1 -2, the tread supports 3 partly protrude from the side elements 1 , 2 when in the mounting position. However, according to another embodiment, the tread supports do not protrude from the side elements 1 , 2 when in the mounting position.

Each side element 1 , 2 of the string assembly is further provided with a set of engagement members 4 positioned at a fixed relative distance along the longitudinal extension of the side elements 1 , 2. The tread supports 3 are pivotally arranged at these engagement members 4. In the exemplifying embodiment of Fig. 1 , the engagement members 4 comprise holes which can receive a protruding element. The protruding element can be a part of the tread support 3. The protruding element can also be an external engaging element, such as for example a bolt, a pin, or a screw, which engages each side element 1 , 2 with a tread support 3. Other engagement members for a pivotal arrangement of the tread supports at the first and second side elements 1 , 2 of the string are possible within the inventive concept, for example protruding portions which are received by an aperture in the tread supports 3. The tread support 3 is thus engaged with the string on both its sides by the engagement members 4 of each of the first side element 1 and the second side element 2.

In the exemplifying embodiment of Fig. 1 , the first side element 1 further comprises a set of fixing members 5 at a fixed relative distance along the longitudinal extension of the string. The fixing members 5 are arranged at a portion of the side element 1 which covers the tread support 3 in a mounting position. Here, the fixing members 5 comprise holes which can receive a fixing element such as a bolt, a screw, a pin, a nail or the like. The fixing member 5 can also comprise a mark for indicating a suitable position at which a fixing element can be inserted. The fixing members 5 are arranged in this manner such to fix the tread supports in the mounting position.

The string further comprises a holding member 8 (partly visible in Fig. 1 ) extending between the first side element 1 and the second side element 2. The holding member 8 is arranged at a portion of the side elements not covering the tread supports 3. The holding member 8 comprises a screw, a bolt, a bar, a pin or similar, which at one side is received in the first side element 1 and at a second side is received in the second side element 2. The length of the holding element is at least as long as the distance between the facing sides of the first and the second side elements 1 ,2. Optionally, a holding element 8 can be provided between each tread support 3 of the string assembly 100 according to an embodiment of the inventive concept.

Continuing now with the tread supports 3, these are further provided with adjusting portions 6. The adjusting portions 6 are arranged at a fixed distance from the support surface 31 of each tread support 3. The adjusting portions 6, in the exemplifying embodiment, comprise non-through holes. However, through holes or hook-like elements can also be used as adjusting portions 6 within the inventive concept. The adjusting portions 6 are further arranged such that the distance between the adjusting portions 6 of two adjacent tread supports 3 in a mounting position corresponds to the distance between the engagement members 4 of the side elements 1 , 2 of the string at which the corresponding tread supports 3 are arranged. In Fig. 1 , the first side element 1 is considered to represent an inner side of the string assembly 100. The inner side refers to the side which faces the second string assembly in a staircase, the staircase comprising a pair of string assemblies and multiple treads. Each tread is supported at opposite ends by the support surfaces 31 of the tread supports 3 of the two string assemblies 100. Fig. 1 therefore shows an inner side view of the string assembly 100.

Correspondingly, Fig. 2 shows an outer side view of the string assembly. That is, the second side element 2 can here be considered as the outer side of the string assembly 100. In other words, the outer side is that directed away from the rest of the staircase.

Referring now to Fig. 3, each tread support 3 further comprises an engagement portion 7, for engagement with one of the engagement members 4 from the set of engagement members 4 of the side elements 1 , 2 of the string. The engagement portion 7 of the exemplifying embodiment of Fig. 3 comprises a hole which can receive a protruding engagement member 4 from the side elements 1 , 2, or an external engaging element such as a bolt, a pin, a screw or the like. The engagement portion 7 can also be a protruding portion which engages directly with one of the engagement members 4 of the side elements 1 ,2.

Continuing with Fig. 3, there is provided an adjusting tool 10 for use when mounting and fixing the tread supports 3 in the mounting position. The adjusting tool 10 is elongated and comprises a first end 1 1 and a second end 12. The first end 1 1 comprises a first engagement member 13, engageable with any one of the adjusting portions 6 of the tread supports 3. The second end 12 comprises a second engagement member 14 which also is

engageable with any one of the adjusting portions 6 of the tread supports 3. The first engagement member 13 and the second engagement member 14 are arranged at a predetermined distance corresponding to the distance between the adjusting portions 6 of two adjacent tread supports 3 when in the mounting position. In the exemplifying embodiment, the first engagement member 13 and the second engagement member 14 comprise protruding pins which can be received in adjusting portions 6 of the tread supports 3.

To mount a staircase comprising two string assemblies 100 as previously described, and treads resting on the support surface 31 of each tread support 3 of the string assemblies 100, a first step comprises cutting the string assemblies 100 in length and with an angle in accordance with the site at which the staircase is to be installed. After cutting, the string assemblies 100 and treads can be packaged in a compact layer and delivered to the installation site within a short time. The string assemblies 100 are thereafter fixed by its upper and lower end to an upper and a lower anchoring point, respectively. The first tread support 3 from the lower end of each of the two string assemblies 100 are then pivoted to a mounting position, which is defined by the position in which the support surface 31 is horizontal. The tread support 3 is fixed in this position by means of the corresponding fixing member 5 of the first side element 1 or the second side element 2 of the string. In order to maintain the outer side of the string assembly 100 clean, that is free from holes or external members, the fixing of the tread supports 3 is preferably made by means of fixing elements on the inner side of the string assembly. According to the exemplifying embodiment of Figs. 1 -3, that is side element 1 . However, the fixing element can well be located on the outer side of the string assembly 100, that is at side element 2, according to the inventive concept.

When the first pair of tread supports have been mounted, the adjacent tread supports 3 of the two string assemblies 100 of the staircase are pivoted to a mounting position, in which the corresponding support surface 31 is horizontal. The tread supports 3 are locked, one at a time, by means of the adjusting tool 10. For this, the adjusting tool 10 is engaged by its first engagement member 13 with the adjusting portion 6 of the already fixed tread support 3, and by its second engagement member 14 with the adjusting portion 6 of the tread support 3 that is being mounted. When the adjusting tool 10 has been engaged with the adjacent tread supports 3, the tread support 3 that is being mounted is fixed by the corresponding fixing member 5 of the first or second side element 1 , 2 of the string. When the tread support 3 has been fixed, the adjusting tool 10 is removed and used for mounting the next tread support 3. The rest of the tread supports 3 are mounted and fixed in the same manner.

Finally, when the tread supports 3 are all fixed in a mounting position, treads extending from one tread support 3 of a string assembly to a tread support 3 at the same height of the second string assembly 100 are mounted at the support surfaces 31 of the tread supports 3 and fixed.

The mounting of the staircase previously described can also be done without the use of the adjusting tool 10. However, using the adjusting tool 10 to adjust and lock the tread support proves efficient in terms of time.

The first side element 1 , the second side element 2, the tread supports 3, the adjusting tool 10 and the treads can be made of any material, such as wood, metal, plastic or composite material.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments.

Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.