The present invention relates to a cantilever system, in particular for a balcony platform, affixed to a load-bearing structure, preferably a separating floor.

In the new building and rehabilitation of an agglomeration of buildings, occasion- nally the need arises to install a certain number of balconies within a short time period and at a lowest possible cost. Hence, use is frequently made of balcony arrangements with prefabricated balcony platforms which can be produced efficiently in a desired number and are subsequently installed on the building.

As used in the following specification, the terms up and down, upwards and downwards and the like refers to the direction in which the balcony elements will be positioned when installed on a building. In accordance with common practice, the rear edge of the balcony denotes its side facing towards the wall of the building. The direction towards the front edge of the balcony is understood to be the direction perpendicularly outward from the wall when the balcony has been installed, even though the front edge may in fact be curved.

Important quality and cost factors of such balcony arrangements are requirements regarding fire safety, strength, attachment and support, thermal isolation between the balcony platform and separating floor (cold bridge), safety and time spent on the construction site in installing the balcony platform, as well as the post- installation of balustrade, drain system, sun-shading, and perhaps balcony glazing. The maintenance expected during the life of the balcony is also an important quality factor.

Existing balcony arrangements can be divided into three main categories:

1 ) concrete, 2) welded metal structures, and 3) pressure impregnated/compreg- nated wood. Problems suffered by the existing solutions are, among others: Concrete:

- Building/wall structure must be reinforced due to the weight of the platform element

- Cutouts in the wall panelling for entering the platform member create a cold bridge (large heat transfer) between the balcony and separating floor

- Extensive post-installation work associated with any adjustment for skew- ness of the building (separating floor/panelling)

- Extensive procedure for installing the balcony platform

o Personal safety

o Long installation time on the construction site due to casting, setting, and fitting of uprights

o Use of heavy and expensive lifting equipment

o Need for scaffolding

o Subsequent installation of balustrade and drain system after the uprights and scaffolding have been taken down

- Extensive need for maintenance

Welded structures:

- A weld is the weakest point of the structure

- Welded arrangements are labour-intensive and expensive

- Welded aluminium arrangements don't satisfy fire safety requirements

- Welded steel structures are heavy and places strict demands on attachment/mounting

- Extensive need for maintenance

Compregnated wood:

- Not fire rated

- Built on construction site

- Best suited for private homes and do-it-yourself building

- Extensive need for maintenance

Figs. 1 a and b (prior art) illustrate in more detail some of the problems faced when installing concrete prefabricated balcony platforms. DE 8302805 U discloses a balcony platform comprised of closely positioned load- bearing, cantilevered light metal hollow profile sections. The profile sections extend continuously along the entire balcony, in parallel with a wall. The profile section adjacent to the wall is provided with a hook-like part and serves as a quick connect to a mounting bracket.

EP 1477400 A1 describes a prefabricated installable balcony comprised of load- bearing, cantilevered profile sections extending perpendicularly outwardly relative to the wall, as well as a top cover. The publication discloses a connecting member serving as a quick connect.

DE 19846816 A1 describes a balcony structure having load-bearing supporting profile sections extending perpendicularly outwardly relative to the wall, as well as a top cover. The profile sections are attached to the load-bearing structure through an elongate connecting member suspended on a hook of the bracket. A cover bracket projects from the separating floor.

JP 8199692 A describes a prefabricated balcony provided with hook-like connecting members allowing for a quick installation.

Much of the time spent on installing concrete prefabricated platforms is hence due to the weight of the platform, e.g. in that it is necessary to establish support legs and that safety measures must be taken to avoid fall and clamp injuries. Many of the same problems are also experienced in the installation of steel or wooden prefabricated balcony platforms.

Normally, balconies made of compregnated wood don't satisfy requirements for fire safety, aesthetics etc. which may be put on balcony arrangements for multi- floor buildings. In general, locally built wooden balconies are too time-consuming to install for them to be able to compete with prefabricated elements of steel or concrete. Another problem with the existing balcony arrangements is that the balcony platform is often poorly thermally insulated against the separating floor. Fig. 1 a shows a typical prior-art solution in which the platform is mounted on an angle bracket 503, which, in turn, is fastened to the separating floor 410. Poor or insufficient thermal insulation allows large amounts of heat to conduct from separating floor 410 to a lower-temperature balcony platform 100'. Hence, during winter, in cold regions, the attachment points at the rear edge of the platform will form a "cold bridge" into the house.

The object of the present invention is to provide a balcony system as well as a method of installation overcoming at least one of the problems set forth above.

The objects of the present invention are achieved by a cantilever system, in particular for a balcony platform, affixed to a load-bearing structure, preferably a separating floor, the cantilever system comprising: a mounting bracket for attachment to the load-bearing structure and extending in the width direction of the balcony platform, the mounting bracket being formed with a receptacle for connecting to a hook-shaped connecting member extending in the width direction of the balcony and in parallel with the mounting bracket, and further characterized in that one or more cantilevered floor sections, at the fastening lateral ends thereof, are mounted to the hook-shaped connecting member along the entire width direction of the balcony platform, the floor sections being arranged adjacent to each other whereby a self-supporting cantilever system is obtained.

Preferred embodiments of the cantilever system are set forth with particularity in claims 2 through 9.

Preferably, the balcony platform is made as lightweight as possible, using hollow aluminium profiles screwed together by way of bolts and brackets, for example.

The balcony system may also include brackets for mounting external or internal rain gutters, baluster pins, and/or adapters facilitating the installation of balustrade, handrail, and/or glazing glass. Profiled plates (covers) and other visible members may be clipped to the balcony to provide a desired surface texture and colour. An aluminium balcony platform, if desired, can be fire-insulated by way of rock wool or similar fibres to obtain a desired fire resistance. Such insulation additionally reduces step sound, and may also reduce the heat loss from normally heated rooms to a colder outdoor balcony.

Additional advantages of the invention are:

- No need for temporary fitting of uprights, casting, and setting (as in the case of concrete)

- Fire insulation enables use at large heights involving fire rating requirements

- Prefabricated brackets embedded into the platform allows for the quick and accurate affixation of hand rails, sun screens, and/or glazing immediately after the balcony platform has been lifted in place and fixed

- Elimination/reduction of heat transport at thermally insulated wall mountings and/or separating floor brackets

- Adjustable wall mountings/separating floor brackets in case of skewnesses and deviations from tolerances in the separating floor and wall panelling of the building

- Preinstalled drain system can be delivered as standard (selectable whether external or internal)

- No-maintenance treated aluminium surfaces

- Lower purchase, installation, and maintenance costs

The invention is described in more detail in the following with reference to the attached drawings, in which:

Figs. 1 a, 1 b illustrate a method of installing a concrete prior art balcony

Fig. 2 shows a cantilever system according to the invention in the form of a balcony platform mounted to a load-bearing structure,

Fig. 3 shows a detail of the main components of the cantilever system,

Fig. 4 shows the balcony platform of Fig. 2 before the installation has been fully completed,

Fig. 5 shows a detail of the main components of the cantilever system before final assembly, Fig. 6 shows a detail of the main components of the cantilever system fully installed, and

Fig. 7 shows two assembled floor profile sections of the cantilever system.

The figures are schematic illustrations of the principles of the invention.

Accordingly, the figures are not necessary to scale, some details are depicted schematically, and other details have been excluded from the figures. In an actual platform, screws, bolts, brackets, mountings, etc. will be present which are well known to a person skilled in the art, but are not shown in the schematic drawings.

Referring to the drawings, a cantilever system 1 , herein in the form of a balcony platform, is shown mounted to a load-bearing structure 3. A mounting bracket 5 is secured to the load-bearing structure 3. Mounting bracket 5 is formed with a receptacle 6 for being connected to a hook-shaped connecting member 10. Mounting bracket 5 with receptacle 6 and the hook-shaped connecting member 10 extends in the width direction of the balcony. A number of cantilevered floor profile sections 15 are secured to the hook-shaped connecting member 10 along the entire width direction of the balcony platform. The combination of mounting bracket 5 with receptacle 6, mounting bracket 5 and deeply cantilevered floor profile sections 15 provides a self-supporting cantilever system.

The main components of the cantilever system are shown in detail in Fig. 3. Receptacle 6 is in the form of a plate structure extending in the width direction of the balcony. The hook-shaped connecting member 10 is provided, respectively, with an upper hooked flange means 1 1 engaging the upper edge region of the plate structure and with at least a flange means 12 resting on the lower plate region of the mounting bracket. Mounting bracket 5 is further provided with threaded holes 7 for the insertion of bolts 18 in floor section screw slots 17.

Referring particularly to Figs. 2 and 4, the cantilevered floor profile sections 15 are shown fitted to frame profile sections 25 extending along the outside free edge regions of the balcony platform and being mounted to the outer free lateral ends and longitudinal sides of the floor sections. Referring to the drawings, and in particular to Fig. 7, the floor sections 15 are shown as a box/hollow profile section, preferably made of aluminium. The floor section fastening lateral end 16 is further provided with screw slots 17 for attachment of the hook-shaped connecting member 10. Floor profile section 15 is further provided with a tongue and groove means 20 for connecting to one or more parallel extending floor profile sections 15. The cantilever system of the present invention can be prefabricated before installation on a construction site. This reduces the overall building costs and saves time on the construction site. The cantilever system can be customized and is virtually maintenance free. The cantilever system provides for a quick and safe installation on the construction site.

The self-cantilevering balcony platform is installed without any vertical support from below or diagonal suspension. The weight is low so that lightweight lifting equipment may be used. Mounting brackets 5 are quickly and precisely secured to a load-bearing structure 3. Cantilever system 1 , herein in the form of a balcony platform having a pre-fitted balustrade, is quickly installed in mounting brackets 5.

The attachment of mounting brackets 5 to the load-bearing structure 3 is carried out in such a manner that cold bridges are eliminated. The support is accomplished by way of an insulated mounting bracket 5 bolted to the separating floor of the building. The bracket acts as a cold bridge breaker. Hence, the balcony platform does not need support from uprights/vertical columns or diagonal strut suspension to the wall, for example.

The cantilevered floor profile sections 15 are provided with a tongue and groove system for connecting/water trapping between the profile sections. The cantilevered floor profile sections encircling the platform additionally form a foundation for balustrade posts and also act as an integrated rain gutter/flood water drain.

Mounting brackets 5 are attached to the building structure in the "concrete phase" thereof. Then the building is covered with wall panelling, with the steel plate of the mounting bracket protruding out of the panelling. When the balcony platform is installed, the hook-shaped connecting member 10 of the balcony platform is hooked onto the mounting bracket receptacle 6. The balcony platform is then secured at the lower edge thereof by way of bolts between the hook-shaped connecting member 10 and mounting bracket 5.

The hook-shaped connecting member 10 provides a fastening point of the balcony platform to the insulated mounting bracket 5 bolted to the separating floor / edge strip of the building. The hook-shaped connecting member 10 is designed with a downward sloping inward towards the wall to achieve a desired sloping for water run-off on the upper side of floor profile sections 15. In this embodiment, the floor profile sections can be cut at right angles to minimize finishing. The hook-shaped connecting member 10 connects all floor profile sections 15 using three self- threaded bolts in each floor profile section 15. In this embodiment, three upper bolts and one lower bolt are used.

In another embodiment, the floor section fastening lateral end 16 may be tilted at an angle to the vertical direction whereby floor profile section 15 slopes towards its free end.

Floor profile section 15 is a box section having two steps and four screw slots (three upper slots and one lower slot). The steps and screw slots are positioned so that the bolts become symmetrically distributed at an equal distance along the entire balcony platform. The objective for doing this is to optimize the distribution of stresses in the hook-shaped connecting member 10.

As mentioned above, floor profile sections 15 are provided with both upper and lower tongue and groove systems to prevent ingress of water between the profile sections.

The bottom face of the floor profile sections forms the ceiling panel of the balcony platform, and could also have fire-resisting plates attached thereto.

The top face of the floor profile section is made skid-proof by way of grooves. Frame profile sections 25 are bolted to floor profile sections 15. A balustrade may be mounted on the top of frame profile sections 25 or on the outside thereof. Frame profile sections 25 are provided with grooves for the attachment of cover panels on the bottom face of the balcony frame to allow for changing the panelling colour (coloured plates) or material (wood, lightweight concrete).

As discussed above, the invention provides a cantilever system which can be prefabricated, transported to the construction site, and installed in a quick, safe, and cost-efficient manner.