EP1606475B1 - Formwork support - Google Patents

Abstract

The aim of the invention is to improve the load-bearing capacity of formwork supports during shock-type stress that is effective especially perpendicular to or at an angle from the longitudinal axis of the support. Said aim is achieved by a formwork support which is made essentially of wood and is provided with a top chord, a bottom chord, and a web that connects the two chords. The web and/or at least one of the chords comprises at least one recess in at least one final area of the support said recess being filled with a filling material that has shock-absorbing properties. The invention also relates to a method for producing such a formwork support.

Description

Technical area

The present invention relates to a formwork support with a top flange and a bottom flange and a web connecting them, which consist essentially of wood, and a method for its preparation.

State of the art

Shuttering of the type mentioned are widely used in construction. The formwork beams are in construction site u. a. exposed to pronounced mechanical loads, in particular shock and impact stresses, such as those caused by a fall of the carrier of a scaffold or the like. There is the risk that the formwork beams are damaged in such a way that they no longer have sufficient dimensional stability or even carrying capacity.

To remedy this situation, various protective arrangements for formwork supports are known in the prior art, in which usually the support ends are provided with caps or the like. For example, DE 43 04 438 A1, which forms the closest prior art, discloses a Holzgurtträger in which a top flange is connected by lattice .oder Vollwandsteg with a lower flange, the strap ends are protected by a cap and at least two edges on the Face of the straps are chamfered. Furthermore, the AT 403 305 B discloses a formwork support with a top flange and a bottom flange and at least one connecting web, wherein the end face of the top flange and the bottom flange a frontal protection is provided, which consists of a castable or sprayable plastic, directly by casting or injection molding is integrally formed on the upper belt or lower belt.

These guards have been found to be quite capable of protecting the formwork beam from shock loads acting on the free beam end (i.e., in the beam longitudinal direction). In practice, however, the most frequent impact stresses occur essentially transversely or obliquely to the longitudinal axis of the carrier, in particular when the carrier falls off a scaffold or the like. In such a stress transversely or obliquely to the longitudinal direction of the impact is usually at an outer edge of the belt. Due to the usually I-shaped carrier cross-section in the belt end, particularly critical stresses occur transversely to the fiber direction in the form of a massive deformation and / or a splitting of the straps. Further high and thus critical stress concentrations therefore occur, due to the carrier geometry and the anisotropy of the wood, in the region of the web / belt connection, in particular with different material properties of the belt and web. As a result of the impact of the carrier is usually no longer usable because he does not have sufficient inertia, but at least no sufficient dimensional stability more.

It should be noted that in a fall of a formwork support from a scaffold or the like both ends of the carrier are always claimed, the last incident carrier end is accelerated when the first end of the carrier is hit, then hit with even greater force on the ground. Here are very high stresses in the carrier transverse direction.

One approach to protect the formwork support against such stresses, for example, was to reinforce the support by screwed or riveted steel dowels or - bolts, so as to increase its strength (EP 0 255 110 B1). This approach led to some improvement in the load carrying capacity of the load in transverse and oblique directions, but often suffered damage the formwork support in normal construction site operation does not effectively prevent.

Presentation of the invention

It is an object of the present invention to provide a generic formwork support whose load-carrying capacity or resistance is improved in the case of impact-like stresses, in particular in the transverse direction of the beam or in the direction of beam obliquity.

This object is solved by the subject matter of independent claims 1 and 13.

The present invention is based on the idea to protect the formwork support not only by means of outer baffle elements, but specifically designed the inner structure such that the deformation capability and hereby also the carrying capacity of the carrier are considerably increased. For this purpose, a formwork support according to the invention with the features of claim 1 is provided.

Due to the construction according to the invention of the formwork support, in particular by the shock-absorbing filling material, this can escape excessive stress peaks at high stresses due to deformation. In this way, the load-bearing capacity of the formwork support can be increased to a surprising extent in the event of impact loads, in particular also in the transverse or oblique direction. At the same time, the carrier still has a simple construction, since a known, generic carrier can be easily modified in the sense of the invention.

According to one embodiment of the present invention, the at least one recess in the web is located adjacent to the upper flange and / or the lower flange. In this way, the critical transition region between web and strap can be particularly be effectively secured, so that in particular a splitting of the belt due to the initiated by the web pressure force can be effectively prevented.

Against this background, it is also provided according to a further aspect of the present invention that the at least one recess in the upper flange and / or in the lower flange is located adjacent to the web. As a result, the bridge is also relieved at the same time, as this is claimed in total uniformly and without voltage spikes, which increases its load capacity.

A particularly advantageous Tragyerhalten also results when the two aforementioned objectives are combined in such a way that the at least one recess extends from the web in the upper flange and / or the lower flange. As a result, stress peaks in the transition region between web and straps can be completely eliminated, which significantly relieves both the straps and the web, so that overall the load capacity is significantly increased against jerky stresses.

A particularly effective damping behavior is achieved according to a development of the present invention in that the filling material substantially fills the at least one recess.

According to a further aspect of the present invention, the recesses according to the invention can also be very advantageously combined with a forehead protector which at least partially covers an end face of the formwork support located in the end region. As a result, the load-bearing capacity of the formwork support is particularly favorable in the case of impact loads both in the transverse direction and in the longitudinal direction of the support.

In this case, it is particularly preferred according to the invention that the end protection at least partially surrounds the end region of the formwork support, in order in this way also to carry the load Contribute the wearer in the transverse or oblique direction. At the same time the clasping of the formwork support, in particular the straps, a splitting or splintering of the wearer when hammering nails or screwing screws reliably prevented.

In order to achieve a simple production of the formwork support according to the invention and to avoid joints in the formwork support, it is preferred according to a development of the present invention that the end protection is formed integrally with the filling material of at least one recess.

It has proved to be particularly advantageous that the filling material and / or the forehead protection is formed by a plastic material which is preferably sprayed or poured. The use of a plastic material allows on the one hand advantageous damping properties and on the other hand a simple, fast and cost-effective production process of the formwork support according to the invention.

It is particularly preferred that the plastic material is PUR, in particular polyurethane-based polyether-based and polyester-based resin. These materials can be processed in high-pressure or low-pressure processes and are therefore also ideal for pouring in at comparatively low pressures. Furthermore, they have also proved to be advantageous due to the excellent damping properties. Furthermore, the PUR can be advantageously filled with additives such as glass fiber, talc, etc.

Other preferred materials are rubber, especially EPDM rubber, and thermoplastic elastomers (TPE). In particular, TPE-S (based on styrene-ethylene-butadiene-styrene), TPE-V (based on EDM / polypropylene) and TPE-U (based on polyurethane) have proved advantageous on account of their excellent damping properties.

It should be noted, however, that the filling material and / or the forehead protection can also be applied individually or integrally as a semi-finished part (s), for example by means of adhesive or the like.

According to a further aspect, the present invention provides that the forehead protection and / or the filling material has at least one reinforcing element, which is preferably made of steel, aluminum or fiber-reinforced plastic. In this way, the formwork support according to the invention, additional strength can be imparted without affecting the advantageous deformation properties, so that the load capacity of the wearer can be further increased in shock-like stresses. For this purpose, it is inventively preferred that the reinforcing elements are formed by rings which engage around the upper flange and / or the lower flange in particular. In this way, the straps are reliably secured against splitting in transverse or oblique stress.

Further, the present invention provides a method of manufacturing a formwork beam according to claim 13. The inventive method allows an industrially feasible and thus economical production of a novel formwork support, which has a significantly improved load capacity at impact load, in particular in the transverse direction and oblique direction, respectively.

With regard to a comparatively simple implementation of the method and simple apparatus for carrying it out, casting the filler over injection molding has the advantage that lower pressures are used. As a result, the seal between a casting or injection mold and the outer contour of the support end is simplified.

In a further development of the method according to the invention, the fixed connection of the web to the upper and lower belt takes place before the introduction of the at least one recess. This means that the preparation of the carrier itself from the introduction of the Recesses can be decoupled, so that any carrier can be subsequently provided with the required or advantageous for the individual application recesses.

It is particularly preferred according to the invention that the at least one recess is sawn or milled from one end face of the web and / or the at least one belt. Thanks to this measure, the at least one recess can be made in a particularly simple manner, and in particular can also be easily introduced to already finished carriers.

Furthermore, according to a further aspect, the method provides that a forehead protector is applied which at least partially covers an end face of the form carrier which is located in the end region, wherein it is particularly preferred for the filling material and / or the forehead protector, in particular integrally, to be applied by spraying or spraying Pouring on a plastic material will be applied. Alternatively, it is of course possible to apply filler material and / or the forehead protection individually or integrally as a semi-finished part (s), for example by means of adhesive or the like.

Brief description of the drawings

Fig. 1

shows a schematic perspective view of a first embodiment of the formwork support according to the invention;

Fig. 2a)

shows a schematic side view of the embodiment shown in Figure 1;

Fig. 2b)

shows a schematic sectional view of the first embodiment of the formwork support according to the invention, wherein the section along the line AA in Fig. 2a) is guided;

Fig. 2c)

shows a schematic sectional view of the first embodiment of the formwork support according to the invention, wherein the section along the line B-B in Fig. 2a) is guided;

Fig. 3

shows a schematic exploded view of a second embodiment of the formwork support according to the invention.

Detailed description of preferred embodiments

Preferred embodiments of the formwork support according to the invention will now be described in detail with reference to the accompanying drawings.

Figures 1 and 2 show schematically a first embodiment of a formwork support 1 according to the invention. The formwork support 1 comprises a top flange 2, a bottom flange 4 and a connecting web 6, all of which consist essentially of wood. The web 6 may be a solid web or, for example, a truss structure or the like. In the present exemplary embodiment, the straps 2, 4 each have a recess 8 in an end region 1 'of the carrier 1 which extends from the end face 1 "of the form carrier 1 into the straps 2, 4. Moreover, the recesses 8 are in the present embodiment arranged such that they are each adjacent to the web 6, that is adjacent thereto, but it is also possible according to the invention that the recesses 8 extend into the web 6 or are provided only in the web 6, in which case an arrangement of the recesses adjacent to the straps 2, 4 is preferred.

The recesses 8 each have a filling material 10, which has shock-absorbing properties and in the present embodiment, the recesses 8 substantially fills. Although a large filling of the recesses 8 is preferred, embodiments with cavities or recesses in the filler 10 are possible. In addition, it is According to the invention, the filling material 10 has at least one width of the overlap (Ü) in the web transverse direction between the web 6 and the grooves 2,4.

Furthermore, the formwork support 1 is provided with a forehead protection 12, which as best seen in FIG. 2 b) is formed integrally with the filling material 10. The frontal protection 12 covers an end face 1 "located in the end region 1 'of the formwork support 1, at least in sections. The frontal protection 12 may also completely cover the end face 1 "of the formwork support 1. In addition, the forehead protection 12 in the present embodiment also surrounds the side surfaces of the upper flange 2 and the lower flange 4.

The filling material 10 and the end protection 12 are each formed of a shock-absorbing material, in particular a thermoplastic elastomer (TPE), preferably TPE-S (based on styrene-ethylene-butadiene-styrene), TPE-V (based EDM / polypropylene) of TPE-U (polyurethane-based), a rubber, preferably an EPDM rubber, or a PUR, preferably a polyether-based or polyester-based PUR casting resin.

Due to the inventive design of the formwork support 1 with the shock-absorbing material 10 in the recesses 8 of the formwork 1 receives an excellent load capacity for impact or sudden stresses, which is significantly increased in particular in transverse or oblique direction of the carrier over conventional carriers. This is achieved, inter alia, by; that thanks to the shock-absorbing filling material, so to speak, an internal suspension of the carrier is achieved, so that it can escape excessive stress peaks in the event of impact or sudden stresses due to deformation. Nevertheless, the carrier still has a simple construction, and in particular requires no elaborate reinforcements such as steel bolts, steel caps or the like.

The formwork support 1 described can be produced, for example, as follows. First, a top flange 2, a Bottom belt 4 and a web 6, which consist essentially of wood, connected together to form a formwork support. Alternatively, it can also be assumed directly from a commercially available formwork support, which has a top flange 2, a bottom flange 4 and a web 6. Subsequently, in the present exemplary embodiment, the recesses 8 are sawed or milled into the web 6 from the end face 1 "of the formwork support 1. The filling material 10 is then introduced into the recesses 8 in each case.

It has proven to be particularly advantageous to apply the filler 10 and optionally an additional end shield 12 integrally by spraying or pouring a plastic material on the formwork support 1. As a result, a faster and more economical production process is achieved, wherein achieved by the spraying or pouring of the plastic material, a particularly good bond between the filler 10 and the end shield 12 and the formwork support 1, since the plastic material can penetrate into the pores of the wood.

Fig. 3 shows schematically a second preferred embodiment of the formwork support 1 according to the invention. Identical or corresponding components are in each case provided with the same reference symbols in FIGS. 2 and 3, and a repeated description of these components is therefore unnecessary. The embodiment shown in Fig. 3 differs from the first embodiment initially in that the forehead protection 12 as such is not made in one piece, but has two straps respectively associated portions which are integral with the filling material 10 of the recesses 8, and above also has a middle, the web associated portion 12 '. This arrangement has the advantage that in the area of the belts 2, 4 or the web 6 each material can be used as a forehead protection, which is tailored to the particular requirements. Thus, it is conceivable, for example, to provide the high-stress belt ends with a high-quality damping material as the frontal protection 12, while in the region of the web, a central portion 12 'is used, which has sufficient damping and sealing properties, but otherwise also in view of the design and the recognition value of the formwork support can be designed.

In addition, the forehead protection in the present embodiment, more precisely, the portions 12 associated with the straps 2, 4, respectively, a reinforcing element 14, which also extends into the provided in the recesses 8 reinforcing material 10. The reinforcing elements 14 are formed in the present embodiment by rings which surround the free end portions of the straps 2, 4, respectively. In this way, the formwork support 1 according to the invention receives in addition to its excellent damping properties a further improved strength, whereby a harmful splitting of the belt ends is effectively prevented.

The reinforcing elements 14 may in principle be arranged at any desired location within the end protection 12 and / or the filling material 10. However, in view of a particularly good effectiveness of the reinforcing elements 14, it is advantageous that the reinforcing elements or rings 14 directly surround the free ends of the straps 2, 4, i. abut directly against these, and are surrounded shock-absorbing to the outside of the filler 10 and / or the frontal protection 12.

The reinforcing elements 14 are preferably made of steel, aluminum or fiber-reinforced plastic. Instead of rings, other reinforcing elements may also be used, for example strips of wood, wood-based materials, metal, plastic or fiber materials, which are arranged so as to reinforce the belt-wood transversely or obliquely to the fiber direction in the region of the belt ends.

The production of the second embodiment of the formwork support 1 according to the invention shown in FIG. 3 also corresponds in principle to that of the first embodiment. It is too Note that the reinforcing elements 14 are preferably pushed after the introduction of the recesses 8 on the ends of the straps 2, 4, to then inject the plastic material for the filling material 10 and the forehead protection 12 integrally or stepwise or to pour. As a result, no separate attachment of the reinforcing elements 14 is required at the strap ends, since the fasteners are included during the ejection or pouring of the plastic material and connected to the strap ends.

Although in the present embodiments an injection of the filling material 10 and the end protection 12 has been described, it is of course also possible to attach these elements in other ways to the formwork support 1 according to the invention, without the beneficial effects of the present invention, in particular the excellent damping properties and the correspondingly improved load-bearing capacity under impact loads are impaired. In particular, it is also provided according to the invention that the filling material 10 and / or the end protection 12, which in each case can also be multi-part, are connected to the formwork support 1 by gluing or comparable techniques.

Claims (16)

1. Formwork carrier (1) with an upper belt (2) and a lower belt (4) and a frame (6) connecting them and consisting substantially of wood, wherein
   the frame (6) and/or at least one of the belts (2, 4) has, at least in an end region (1') of the carrier, at least one recess (8), which in the case of a belt (2, 4) is situated at least in the region of a covering (Ü) of the frame (6) and bordering on the frame (6), the at least one recess (8) being provided with a filling material (10) which has shock-absorbing properties.
2. Formwork carrier according to claim 1, characterised in that the at least one recess (8) is situated in the frame (6) adjacent to the upper belt (2) and/or the lower belt (4).
3. Formwork carrier according to one of the preceding claims, characterised in that the at least one recess (10) [sic] extends from the frame into the upper belt (2) and/or the lower belt (2) [sic].
4. Formwork carrier according to one of the preceding claims, characterised in that the filling material (10) substantially fills the at least one recess (8).
5. Formwork carrier according to one of the preceding claims, characterised in that it further has a front protector (12) which at least partly covers a front face (1'') of the formwork carrier (1) situated in the end region (1').
6. Formwork carrier according to one of the preceding claims, characterised in that the front protector (12) is formed integrally with the filling material (10) of at least one recess (8).
7. Formwork carrier according to claim 5 or 6, characterised in that the front protector (12) at least partly surrounds the end region.
8. Formwork carrier according to one of the preceding claims, characterised in that the filling material (10) and/or the front protector (12) is formed by a plastic material which is preferably sprayed on or cast on.
9. Formwork carrier according to one of the preceding claims, characterised in that the filling material (10) and/or the front protector (12) comprises a rubber material, a thermoplastic elastomer or a PUR.
10. Formwork carrier according to one of the preceding claims, characterised in that the filling material (10) and/or the front protector (12) has at least one reinforcing element (14), preferably made of steel, aluminium or fibre-reinforced plastic.
11. Formwork carrier according to claim 10, characterised in that the at least one reinforcing element (14) is formed by a ring which preferably surrounds the upper belt (2) and/or the lower belt (4).
12. Method for producing a formwork carrier (1) consisting substantially of wood, with an upper belt (2) and a lower belt (4) and a frame (6) connecting them, the method comprising the following steps:

    producing a firm connection between the frame (6) and both the upper belt (2) and the lower belt (4) round a formwork carrier (1),

    inserting at least one recess (8) in the frame (6) and/or at least one of the belts (2, 4) at least in an end region (1') of the formwork carrier (1), which in the case of a belt (2, 4) is situated at least in the region of a covering (U) of the frame (6) and bordering on the frame (6) and

    inserting a filling material (10), which has shock-absorbing properties, into the at least one recess (8).
13. Method according to claim 12, characterised in that the firm connection of the frame (6) to the upper and lower belts (2, 4) takes place before the at least one recess (8) is inserted.
14. Method according to claim 12 or 13, characterised in that the at least one recess (8) is sawn in or cut in, starting from a front face of the frame (6) and/or the at least one belt (2, 4).
15. Method according to one of claims 12 to 14, characterised in that a front protector (12) is further applied, which at least partly covers a front face (1") of the formwork carrier (1) situated in the end region (1').
16. Method according to one of claims 12 to 15, characterised in that the filling material (10) and/or the front protector (12) are applied by spraying on or casting on a plastic material.

Images