EP0004604B1 - Stair tread and method for its manufacture - Google Patents

Description

The invention relates to a stair step consisting of a formwork that essentially forms the lost surface of miter-cut and glued formwork panels, in the interior of which a reinforcement is arranged, and a hardened filler made of cement-bound concrete poured into the space between the reinforcement and the formwork , which connects the formwork with the reinforcement, and with adhesive bridges between the concrete and the formwork.

Such a step is known from DE-U-6 806 225. The lost formwork used there consists of individual slabs, which, however, have to be insensitive to water, i.e. marble slabs and other natural stone slabs, asbestos cement fiber boards, plastic slabs or the like, so that the connection of these slabs with cement-bound concrete as filler compound does not cause any difficulties. The individual panels, which can be roughened on the inside, are mitred and glued together. After installing reinforcement, the interior of the lost formwork is filled with cement-bound concrete. The roughening of the inside of the slabs forms adhesive bridges between the concrete and the formwork.

Another step is known from DE-U-7 523 309. The lost formwork can consist of thin-walled natural stone, artificial stone, ceramic, wood or the like. The individual panels of the formwork are butted together. The reinforcement consists of bars, strips or mats, preferably glass fiber mats.

A briefly hardening, shrink-free, plastic-bound concrete is used as the filling compound, i.e. not a conventional concrete that would harden with the use of cement. The plastic-bound concrete has no water, so that its processing poses no problems, especially with lost wooden formwork. However, this plastic-bound concrete has the disadvantage of a relatively high price. The lost formwork can be provided with an adhesive on its inner surface, which forms an adhesive bridge to the load-bearing element, ie the plastic-bound concrete with its reinforcement. In most cases, however, this adhesive is not required.

FR-A-847 443 discloses reinforced flat plates, that is to say essentially two-dimensional structures, in which the plate forming the visible surface consists of a material which is not very resistant, for example glass, porcelain or other transparent or translucent materials. This visible panel can also be made of wood or metal. In any case, it is provided with a reinforcement on the back to achieve the necessary strength. For this purpose, a reinforcement made of ribs arranged in a grid-like manner is first glued to the back of the visible plate with the aid of an adhesive substance, the ribs having a dovetail-shaped cross section in order to form undercuts in this way, which are later poured out with concrete. An enamel melt or other decorative adhesive can be used as the adhesive substance in connection with a transparent glass plate, for example. The reinforcement ribs initially attached can be made of steel or other resistant material. The identical material of the visible plate can also be used. At the points of the adhesive substance where there is no reinforcement, pebbles, grit or the like which form adhesive bridges are embedded before the concrete, mortar or the like is poured between the reinforcement ribs. The concrete reaches into the spaces between the pebbles and the undercuts of the reinforcing ribs.

The invention has for its object to develop a stair step of the type described in such a way that it has the decorative advantages of a surface made of wood while maintaining the use of a cheap filling compound made of cement-bound concrete with the possibilities of easy installation of reinforcement. The use of the previously expensive, relatively expensive plastic-bound concrete should be dispensable and the possibility should be created to calculate and use stair steps with the appearance of wood as fully-fledged static components, as is possible with stair steps made of reinforced natural or artificial stone.

According to the invention this is achieved in that the lost formwork is made of wood and a separating layer of synthetic resin is provided between the interior surface of the wooden formwork and the concrete, with which the wooden formwork is glued in the area of the miter joints, and that as adhesive bridges between the Concrete and the wooden formwork forming undercuts and / or anchoring means connecting the concrete are provided.

The use of the separating layer made of synthetic resin makes it possible for the first time on a stair step to use cement-bound, reinforced concrete in connection with a surface made of wood, because the separating layer prevents the water contained in the concrete from penetrating into the wood when hardening; the danger of the destruction of the wood and the destruction of the bond between the wooden formwork and the concrete is thus eliminated. The synthetic resin layer also performs its second function, namely the creation of the connection between the lost formwork and the concrete, by bonding bridges between it and the concrete through the anchoring means, e.g. B. pebbles, chippings or the like held by the synthetic resin layer are created. With these anchoring means, e.g. B. pebbles, grit or the like. It is a relatively coarse-grained material, that is about within the order of one to ten millimeters. This material is sprinkled on the synthetic resin. A sanding process is also conceivable. As soon as the synthetic resin has set and the pebbles, the chippings or the like are firmly anchored, the filling compound made of concrete, also lightweight concrete, can be poured in, so that the pebbles, the chippings or the like are partially formed by the concrete and partially enter into a connection with the concrete, so that the adhesive bridges are made in this way. A third advantage of the separating layer made of synthetic resin can be seen in the fact that its arrangement in the area of the miter joints results in reinforcement and stiffening precisely at these sensitive points of the stair step, in particular also at the edge that is used on the later stairs and thus on is most likely to be impaired. The miter surfaces are connected to each other and stiffened by the synthetic resin, so that edges with a phase are formed on the step that are especially designed for stress.

Another major advantage of the new stair tread is that it can be easily manufactured and installed by concrete specialists, because the use of cement-bound concrete is no specialty or requires special knowledge for the professional groups working with it. The lost formwork with the immunization through the synthetic resin separating layer can be produced centrally in large quantities, while further processing, in particular the installation of the reinforcement and pouring with concrete, can take place locally at the processing location.

The stair step can be assembled from a lost wooden formwork from four or five individual slabs to form free steps, whereby if the wall formwork is not installed on the wall, the opening of the wooden formwork serving to introduce the filling compound can be closed by a wooden plate or the like. But it is also possible that the wooden formwork is composed of at least two panels.

It is particularly advantageous for the wooden formwork to be made of veneered wood, so that chipboard, blockboard or the like can be used for the other parts or layers of the wooden formwork, which have the advantage of being free from warping over natural solid wood. The use of veneered wood gives great freedom of design, so that the various decorative effects of each type of wood can be fully appreciated.

The separating layer can consist of polyester, acrylic, epoxy resin or the like. What is essential is a synthetic resin that is impermeable to water, so that the lost wooden formwork is effectively protected against the water attack by the concrete.

It is also possible that the individual panels of the lost wooden formwork, for better anchoring with the concrete, have recesses on the inside, undercuts, in particular dovetail-shaped grooves, which are covered by the separating layer made of synthetic resin. This measure can be used alone or else in connection with sanding or the like. It is also possible to insert holders into the dovetail-shaped grooves, which, on the other hand, anchor themselves in the concrete when it penetrates. The holders can be designed as plastic injection molded parts.

The miter on the individual panels of the lost wooden formwork is cut at a greater angle than 45 °, preferably 46.5 °, so that a substantial stiffening is achieved in the area of this edge, but on the other hand the visible gap filled with synthetic resin on the outer surface remains as small as possible. It is also easily possible to rework the steps on the outer surface in the area of these edges.

Such steps can be made in different ways. A particularly advantageous manufacturing process is characterized in that the lost formwork is formed from individual panels of wood and these individual panels are connected and sealed at the same time in the unwound state on the later outside of the stair step with a slight mutual distance in the area of the miter joints by an adhesive tape and that the miter surfaces and the surface of the wooden formwork delimiting the interior are provided with a separating layer made of synthetic resin, on which anchoring means forming undercuts between the concrete and the wooden formwork and / or a connection arriving with the concrete are arranged as bonding bridges. The adhesive tape is used in the unwound state of the individual plates, ie the individual plates are placed next to one another on a flat surface in the required assignment and connected to one another with an adhesive tape. If three panels collide in the area of a corner of a step, it is advisable to secure and seal one of these edges with the adhesive tape only at a later point in the manufacturing process. The miter surfaces and the surface of the wooden formwork delimiting the interior are provided with the synthetic resin, that is, for example, painted or sprayed. Then she can Wooden formwork erected and the angular positioning of the individual panels, the plastic resin after attaching the anchoring z. B. the pebbles, grit or the like. Are brought to hardening. The reinforcement is then installed and the interior of the wooden formwork - possibly using an auxiliary formwork - is poured with cement-bound concrete and hardened. It is particularly pointed out that the miter joints in the area of the miter surfaces are connected and stiffened by the synthetic resin, so that a perfect edge is formed at the step here. The addition of a phase does not have a disruptive effect either.

The opening of the wooden formwork used for introducing the filling compound can also be covered by a wooden plate after the filling compound has hardened, so that in this way steps are created which have six visible surfaces. If the stairs are integrated into a wall, this cover is not required.

• Fig. 1 eine perspektivische Ansicht der Treppenstufe,
• Fig. 2 einen Schnitt gemäß der Linie 11-11 in Fig. 1,
• Fig.3 eine Draufsicht auf einen Teil der verlorenen Schalungsplatte von innen gemäß der Linie 111-111 in Fig. 2,
• Fig. 4 die Darstellung einer Ecke der Treppenstufe gemäß Fig. 2 in vergrößernder Darstellung,
• Fig. 5 die Darstellung einer Ecke der Treppenstufe in einer anderen Ausführungsform,
• Fig. 6 eine schematische Ansicht der beiden Platten für eine Trittstufe in einem ersten Verfahrensschritt,
• Fig. 7 die Platten gemäß Fig. 6 in einem weiteren Verfahrensschritt,
• Fig. die Platten in einem noch weiter fortgeschrittenen Herstellungsstadium und
• Fig. 9 eine Ansicht einer Kellertreppe, belegt mit Trittstufen gemäß Fig. 6 bis 8 und Setzstufen.

The invention is further described using a preferred exemplary embodiment: It shows

• 1 is a perspective view of the step,
• 2 shows a section along the line 11-11 in Fig. 1,
• 3 is a plan view of part of the lost formwork panel from the inside according to line 111-111 in FIG. 2,
• 4 shows an enlarged view of a corner of the stair step according to FIG. 2,
• 5 shows the representation of a corner of the step in another embodiment,
• 6 shows a schematic view of the two plates for a step in a first method step,
• 7 shows the plates according to FIG. 6 in a further method step,
• Fig. The plates in an even more advanced manufacturing stage and
• Fig. 9 is a view of a basement staircase, covered with steps according to FIGS. 6 to 8 and risers.

The step 1 has a lost wooden formwork 2, which forms the surface of the step 1 visible from the outside. According to FIG. 2, the wooden formwork 2 is composed of various miter-cut panels 3. As a rule, five plates 3 are used for the production of free steps. If step 1 is to be completely closed, a sixth plate is used.

The lost wooden formwork 2 consisting of the panels 3 is provided on its inner surface and in the area of the miter joints on the miter surfaces with a separating or connecting layer 4 made of synthetic resin. Pebbles, grit or the like 5 are embedded or anchored in this separating layer 4 in the region of the inner surface, in such a way that their essential surface protrudes from the separating layer 4. In this way, adhesive bridges are formed between the plates 3 and the concrete 8. The synthetic resin connects the miter surfaces of the plates 3 to one another.

A reinforcement 7, for example made of a steel mat, is introduced into the interior 6 thus formed in a positionally correct and non-displaceable manner. The remaining space is poured with cement-bound concrete 8, also lightweight concrete, so that the reinforcement 7 is enclosed and the concrete 8 also forms the pebbles, the chips or the like. 5. The water contained in the cement-bound concrete 8 cannot attack or negatively influence the lost wooden formwork 2 due to the arrangement of the separating layer 4 made of synthetic resin.

Fig. 3 shows a partial view of a plate 3 of the lost formwork 2, on which the separating and connecting layer 4 is applied, which holds the pebbles, the chips or the like. 5 firmly anchored. The pebbles, the chips or the like have a size of about 1 to 10 mm.

4 shows an enlarged view for the purpose of illustration. The panels 3 of the lost formwork 2 are mitred at 46.5 °. The separating layer 4, which holds the pebbles, the chips or the like 5 firmly anchored, is applied on the inside and in the area of the miter surfaces. These pebbles, chippings or the like 5 are firmly enclosed by the concrete 8, as is the reinforcement 7, so that continuous adhesion is thereby achieved.

5 shows a possibility of how, instead of or in addition to the pebbles, grit or the like which form the bonding bridges, recesses having undercuts can be provided in the individual plates 3 on the inner sides, which in particular in the corner regions provide a perfect connection to the concrete 8 guarantee. Dovetail-shaped grooves 9 have proven themselves as recesses. Other shapes are also conceivable.

8 to 8 illustrate the manufacture of a step using the example of a step. It is supposed to be a step that does not need to have a wooden end face, which should be placed on the raw staircase of a cellar staircase, for example, between two walls. So only the two plates 3 are required. these are first mitered at the common edge, so that the miter surfaces 11 are formed. These two plates 3 are then positioned with their later outer side pointing upwards on a flat base with a slight mutual distance between them and connected to one another along the common edge with an adhesive tape 10. The structure from the two plates 3 is then turned over and brought into the position according to FIG. 6, the connecting and separating layer 4 made of synthetic resin being applied in such a way that the surface of the plates 3, which will later form the interior, as well as the miter surfaces 11 and the dovetail-shaped grooves 9 are reached or covered by the synthetic resin. Then one of the two plates 3 is erected vertically, as shown in FIG. 7. The angle of 90 ° is maintained and the synthetic resin is cured by means of auxiliary and holding means 12, which are only shown schematically. So that the plates 3 are connected at an angle and firmly together. This wooden formwork 2 then reaches an auxiliary formwork 13, where the reinforcement 7 is inserted and poured out with the concrete 8 or with lightweight concrete. The concrete 8 also simultaneously produces the adhesive bridges in the dovetail grooves 9. In addition, holders 14 can be inserted into the dovetail-shaped grooves 9 before the concrete 8 is poured in, as can be seen in FIG. 9.

FIG. 9 shows an application of the step 17 according to FIGS. 6 to 8 in connection with risers 18, in which only a single plate 3 is used. this plate 3 does not have to be mitred.

Claims (9)

1. Stairway step constituted by a permanent formwork which essentially forms the step surface, this formwork being made of formwork slabs (3) cut with mitred edges and adhesive-bonded there, a reinforcement (7) being located in the space (6) inside the formwork, and by hardened filler of cement-bound concrete (8), cast into the space between the reinforcement (7) and the formwork, said concrete joining the formwork to the reinforcement, and with adehesive-bonded joints between the concrete (8) and the formwork, characterised in that the permanent formwork consists of wood and that a separating layer (4) of synthetic resin is provided between that surface of the wooden formwork (2) which delimits the interior space (6) and the concrete (8), with which layer the wooden formwork is at the same time adhesive-bonded in the region of the mitred joints, and that anchorage-means, forming undercuts and/or entering into a connection with the concrete (8), are provided as adhesive-bonded joints between the concrete (8) and the wooden formwork (2).

2. Stairway step according to Claim 1, characterised in that the anchorage-means are composed of pebbles, stone chippings, or the like, bonded with the separating layer (4) of synthetic resin.

3. Stairway step according to Claim 1 or Claim 2, characterised in that the wooden formwork (2) consists of wood which is veneered on the outside.

4. Stairway step according to one of Claims 1 to 3, characterised in that the separating layer (4) consists of polyester resin, acrylic resin, epoxy resin, or the like.

5. Stairway step according to Claim 1 or Claim 2, characterised in that, for better anchorage to the concrete (8), the individual slabs (3) of the permanent wooden formwork (2) possess recesses, located on the inner side and having undercuts, in particular dovetail grooves (9), these recesses being covered by the separating layer of synthetic resin. ,

6. Stairway step according to Claim 5, characeterised in that holders (14) are pushed into the dovetail grooves (9), these holders anchoring themselves in the concrete (8).

7. Stairway step according to Claim 1, characterised in that the mitred edges are cut, in the individual slabs (3) of the permanent wooden formwork (2), at an angle greater than 45°, preferably at 46.5° .

8. Process for producing a stairway step (1) constituted by a permanent formwork which essentially forms the step surface, this formwork being made of formwork slabs cut with mitred edges and adhesive-bonded there, a reinforcement (7) being fitted into the space inside the formwork, and the space between the reinforcement (7) and the formwork being filled by casting a filler of cement-bound concrete (8) into said space, characterised in that the permanent formwork is formed by individual wooden slabs (3) and that these individual slabs (3) are connected, in the deployed state, with a small mutual clearance, on the side of the stairway step which will later be the outside, in the region of the mitred joints, by means of an adhesive tape (10), and are the same time sealed, and that the mitred surfaces and the surface of the wooden formwork which delimits the interior space are provided with a separating layer (4) of synthetic resin, on which anchorage-means, forming undercuts and/or entering into a connection with the concrete (8), are located, as adhesive-bonded joints between the concrete and the wooden formwork.

9. Process according to Claim 8, characterised in that the opening in the wooden formwork, serving for introducing the filler, is also covered by a wooden slab.

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