EP0392336A1 - Arrangement used while erecting concrete shutterings - Google Patents

Abstract

In an arrangement used while erecting concrete shutterings, there are provided spacers (1) which are produced as ready-to-use units in each case from an anchor bar (2) and two supporting parts (3), made of corrosion-resistant material or provided with such a material, at the ends of the anchor bar (2), the supporting parts (3) being firmly connected to the anchor bar (2). The supporting parts (3) possess screw-in threads (7), ending in the manner of blind holes, for tension bars (17). The screw-in threads (7) and the corresponding threads on the tension bars (17) advantageously have a special design with regard to their profile. <IMAGE>

Description

The invention relates to a system according to the preamble of claim 1.

For concrete formwork, it is important, on the one hand, to ensure that the required distance between the formwork walls is maintained. In addition, the formwork walls must be clamped together so that they can withstand the pressure of the filled concrete.

In the case of a method which has been customary for a long time, a correspondingly long tensioning rod is used which runs from one side to the other through the formwork. To secure the distance, a plastic tube is pushed onto the tension rod, on the ends of which cones are placed, which come to rest on the formwork walls. The parts of the relevant tensioning rod that protrude from the formwork on both sides are used to attach those parts, such as shims, clamping nuts, etc., with which the formwork is tensioned. In devices of this principle, which is also referred to as "tensioning", the idea of recovering the tensioning rod when dismantling the formwork after the concrete had set played an important role.

The bracing process has a number of problems. When erecting the formwork, the plastic pipes delivered in longer lengths are cut accordingly on the construction site, the separate cones have to be put on, the spacer made on site has to be pushed onto the tensioning rod and this has to be threaded into the formwork. When removing the formwork, the cones have to be removed, the open ends of the plastic pipe have to be closed separately, if necessary, and the remaining conical openings have to be greased with mortar. These are diverse and sometimes very complex work steps.

In addition, cavities in the concrete are always left behind in structures that were built with formwork according to the span principle. This makes it possible for moisture to creep through, allows undesired sound transmission and can also lead to other intolerances or even dangers.

In the case of concrete walls that are subject to higher requirements with regard to impermeability to water, the through-tensioning method with the recovery of tension rods cannot be used because of the remaining voids. Another type of known device must then be used, namely one in which there is a threaded spacer or tie rod made of structural steel which remains in the concrete. The length of this spacer or anchor rod is less than the distance between the formwork walls. Certain conical parts are screwed onto the ends of the anchor rod for bearing against the formwork walls, which consist of a steel inner body with a thread and a rotatable outer body made of plastic with a conical jacket area exist. Tension rods or similar tensioning elements are screwed into the cone parts from the outside, or other parts such as plates, nuts or the like. are assigned to tension the formwork.

Problems of various kinds also exist with such devices. Before installation, the cone parts must be screwed onto the ends of the anchor rod and unscrewed again after removal of the formwork. They have to be screwed out of the finished concrete, which can be difficult. Before such cone parts are reused because of their value, they often have to be cleaned with corresponding effort. A particular problem also lies in how an undesired or inadmissible twisting or even loosening of the parts screwed together can be reliably prevented. The risk of this is often present to a great extent under the various influences and loads that occur on the construction site in general and when the device is installed, particularly when the concrete is shaken. Finally, even with these clamping devices, there is a need to lubricate the relatively large openings remaining after the cone parts have been unscrewed.

The requirements for the individual walls or parts of the building are often different in the same construction project. With some of them, cavities can be accepted, for example, so that the so-called through method is provided, while other walls should be as tight as possible, so that only the other type of the devices explained above can be used. This requires careful planning with appropriate decisions already in the preliminary stage, i.e. before the start of construction. It must then be taken into account in the work preparation, which formwork for one and which formwork is used for the other component. Accordingly, all of the different material for the erection of the different types of formwork must be procured or made available.

The object of the invention is to show a way that takes into account existing difficulties and inadequacies in the construction of concrete formwork, in particular in order to facilitate the operations to be carried out, to simplify these and the preparatory work and to be able to meet accuracy requirements as well as possible. The invention also strives for advantageous designs of the elements used in detail. Further problems connected with all of this, with which the invention is concerned, result from the respective explanation of the indicated solution.

The invention provides that spacers for supporting the formwork walls in each case from an anchor rod and from two made of corrosion-resistant or rustproof metal material or provided with a corrosion-resistant material, blind hole-like screw-in thread for supporting parts having support elements at the ends of the anchor rod as ready-to-use units under a fixed connection the support parts are produced with the anchor rod and that the support parts or the like for bearing against the inside of the formwork walls or against abutments used in these. have suitable end faces which are at a fixed distance from one another as a result of the production of the element, in particular a distance which is equal to the desired distance of the formwork walls from one another, the units introduced into the formwork being left completely in the formwork after the concrete filled into the formwork has set.

The support parts consist in particular of corrosion-resistant or stainless steel. However, other metallic materials that meet the requirements are not excluded. Furthermore, the support parts can be made of a material that is itself not or not sufficiently corrosion-resistant, in which case the resistance to corrosion by a coating, clothing, coating or the like. is effected from a suitable material. This can include done by dipping or molding.

A number of essential advantages are achieved with the invention. Only one principle is used to achieve dense concrete everywhere. Time-consuming and tedious dispositions for the procurement or storage of different devices and accessories are no longer necessary. Because the unit to be used, consisting of the anchor rod and supporting parts, is already available, there is no longer any need to screw together at the construction site. As a result, errors or inaccuracies can no longer occur, which cannot otherwise be ruled out during this work or when handling the individual parts roughly on the construction site. The prefabricated spacer unit has an exact length. Therefore, an absolute dimensional accuracy of the walls or other components is achieved without difficulty. There is no waste and no waste like with parts that only have to have the correct dimensions on site. A particularly important advantage is that there are no large openings in the concrete after stripping, so that the complex work of lubricating such openings is eliminated. Nevertheless, the concrete has an impeccable appearance that normally does not require any modification or rework. The support parts are useful on their end faces matt and can be color-matched to the concrete. The invention also does not exclude the support parts in the end region with a cap, a cover or the like. to provide. If there is a desire to close the small thread ends that are open on the end faces of the support parts, this can be achieved with a plug that can be inserted quickly, in particular made of plastic or stainless steel. The plug can have a thread so that it can be screwed into the screw-in thread of the support parts.

The screw-in threads of the support parts remain easily accessible, if necessary after removing a stopper, so that they can be used as anchor or fastening points for work to be carried out later on the building. This is another important advantage.

The external tension rods required for the construction of the formwork and for tensioning the same can be kept in stock by any building contractor so that they are always suitable for the formwork beams and crossbeams or frame formwork to be used. The use of very long bars, such as the through-tension method, which necessarily protrude far on thin walls, narrow the working area and can lead to injuries, is eliminated.

The support parts of the system according to the invention can be produced in whole or in part by mechanical processing. The production by casting is very advantageous. Special requirements can also be easily met.

The support parts expediently have a matt or rough surface, at least on their circumference, which further improves the adhesion in the concrete. Such a surface can be in the case of cast support parts by the casting process, but can also be produced in other ways, in particular also by immersing the support part in a suitable coating material.

The support parts advantageously have an external shape that deviates from a rotationally symmetrical shape. This ensures security against twisting if desired. The external shape can e.g. be polygonal or have another non-circular contour, in particular also lateral projections or the like. exhibit.

The anchor rod can be a substantially smooth rod. However, it is advantageous at least at its ends to be provided with a thread, for example a metric or similar thread, or with a profiling. The anchor rod can also consist of so-called reinforcing steel with a thread-like profile. In the cases mentioned, the support parts expediently each have a threaded bore which ends as a blind hole and into which the relevant end of the anchor rod can be screwed. This is favorable for the mutual fixing of the parts to one another.

Regardless of its other design, the anchor rod can additionally be provided with at least one blocking element for water, for example in the form of a plate or disk directed transversely to its axis, which can be welded or otherwise attached to the anchor rod.

The fixed connection of the support parts with the anchor rod can be effected in various ways, such as by a shrink connection, by welding and / or by pressing, squeezing or the like. of the support parts on the ends of the anchor rod. In the case of the latter types of connection in particular, it is advantageous if at least the ends of the anchor rod have a profile or thread. The Support bodies can have smooth receiving bores as blind holes for the ends of the anchor rod. In particular, the blind holes are also provided with a profile or thread.

Because there are only blind holes in the support parts, there is no passage or connection path for moisture or gaseous media, so that the finished concrete component is always tight.

In a system for use in the construction of concrete formwork, in which threaded clamping elements are screwed into support parts or the like at the ends of an anchor rod. are, in particular a system with one or more of the features explained above, the invention provides for the clamping elements and for the screw-in thread of the support parts thread with a pitch of 6 mm. Such a thread has the advantage that it is largely insensitive to influences that could loosen the connection. This is essential for use in formwork construction and for handling such parts on the construction site. Furthermore, the associated parts or their threads can be kept shorter in the case of bars with such a thread than in the larger thread pitches conventionally used. Finally, there is also a more precise adjustability.

In a system for use in the construction of concrete formwork, in which threaded clamping elements are screwed into support parts or the like at the ends of an anchor rod. are, in particular a system with one or more of the features explained above, the invention provides a thread for the clamping elements with the following features, to which the screw-in thread is designed to match:
the thread profile seen in the longitudinal section has a base area, a head area and a transition area between the two,
- the contour of the basic area is at least predominantly an arc,
the contour of the head area is at least predominantly a straight line running parallel to the thread axis,
- The transition area has at least partially an arcuate contour.

Such a thread is particularly well suited for all screw connections that are to be carried out when erecting and dismantling concrete formwork with tension rods, anchor rods and the parts assigned to them. This applies among other things for the creation and loosening of these threaded connections as well as with regard to the load-bearing capacity and also largely insensitivity to the effects occurring on the building.

The radius of the circular arc contour of the base area is advantageously approximately 1.4 mm, although other values are also not excluded.

A radius of approximately 1.0 mm is favorable for the circular arc contour of the transition area. However, other values can also be considered.

The head width of the thread is a measure that can be measured between the intersections of tangents at the turning point of the profile or such corresponding intermediate parts with extensions of the straight line of the head contour. In an advantageous embodiment of the thread, the head width is approximately 2.6 mm. However, other values are not excluded here either.

The respective angle between a tangent to a turning point or a corresponding intermediate section of the profile and a radius line or a perpendicular to the straight line of the head contour is advantageously approximately 30 °.

In a system for use in the construction of concrete formwork, in which threaded clamping elements are screwed into support parts or the like at the ends of an anchor rod. are, in particular a system with one or more of the features explained above, the invention provides for clamping elements and for screwing threads of the support parts, namely threads with outer diameters of about 17 mm, 23 mm and 29 mm.

The core diameter of a thread for clamping elements and for screw-in threads of the supporting parts is - especially in the case of the aforementioned outer diameters - advantageously about 14 mm or 20 mm or 26 mm.

• Fig. 1 eine Ausführung einer Abstandhaltereinheit in Ansicht,
• Fig. 2 einen Teil einer anderen Ausführung einer Abstand­haltereinheit in Ansicht,
• Fig. 3 eine beondere Ausbildung eines Gewindes in ver­größerter Schnittdarstellung,
• Fig. 4 einen Vertikalschnitt durch den mittleren Bereich einer Schalung für eine Wand,
• Fig. 5 einen Vertikalschnitt durch den außenliegenden Teil der Schalung nach Fig. 4 auf einer Seite derselben,
• Fig. 6 einen Stützteil in einem Längsschnitt nach der Linie VI-VI in Fig. 7,
• Fig. 7 eine Rückansicht des Stützteiles nach Fig. 6,
• Fig. 8 eine andere Ausführung eines Stützteiles in einem Längsschnitt nach der Linie VIII-VIII in Fig. 9,
• Fig. 9 eine Rückansicht des Stützteiles nach Fig. 8,
• Fig. 10 eine weitere Ausführung eines Stützteiles in axialem Längsschnitt,
• Fig. 11 einen Stopfen in Seitenansicht und
• Fig. 12 eine Stirnansicht zu Fig. 11.

Further details, features and advantages of the invention result from the following explanation of exemplary embodiments, from the associated drawing and from the claims. Show it:

• 1 shows an embodiment of a spacer unit in view,
• 2 shows a part of another embodiment of a spacer unit in view,
• 3 shows a special design of a thread in an enlarged sectional view,
• 4 shows a vertical section through the central area of a formwork for a wall,
• 5 shows a vertical section through the outer part of the formwork according to FIG. 4 on one side thereof,
• 6 shows a support part in a longitudinal section along the line VI-VI in FIG. 7,
• 7 is a rear view of the support member of FIG. 6,
• 8 shows another embodiment of a support part in a longitudinal section along the line VIII-VIII in FIG. 9,
• 9 is a rear view of the support member of FIG. 8,
• 10 shows a further embodiment of a support part in an axial longitudinal section,
• Fig. 11 is a plug in side view
• 12 is an end view of FIG. 11.

In Fig. 1 a spacer is shown, which forms a finished unit 1 for installation in a formwork. An anchor rod 2 is fixedly connected at its ends to support parts 3, each of which has a collar 8 and their end faces 4 are intended for direct contact with the walls of the formwork to be erected. The distance A of the end faces 4 from each other, which is determined during the manufacture of this unit 1, is therefore equal to that desired distance between the formwork walls to be erected and thus the thickness of the wall to be concreted.

The anchor rod 2 has a thread 5 in the embodiment according to FIG. 1. It can be a common thread or a thread-like profile, as it is e.g. in the case of reinforcing steels, but in particular around a thread, as will be explained in more detail in connection with FIG. 3. The support parts 3 are each provided with a corresponding thread in blind holes (cf. thread 9 in FIGS. 4, 6, 8 and 10), so that they can be screwed to the anchor rod 2 during the manufacture of the unit 1. The final connection of the parts can then take place by welding or by pressing the support parts 3 with the anchor rod 2. The latter is the case in the embodiment according to FIG. 1. The number 6 indicates deformation points caused by a tool attack during pressing. A slight squeezing or pressing of the support part is sufficient to achieve a secure cohesion.

Each support part 3 is also provided in a blind hole open to its end face 4 with a screw thread 7 for a clamping element. The thread 7 and the corresponding thread of the tensioning element can be of the same type as the external thread 2 of the anchor rod 2. In particular, it is a suitable internal thread for the external thread shown in FIG. 3.

The embodiment of a spacer unit 11 shown in FIG. 2 is a smooth anchor rod 12 which engages with its ends in blind holes 18 of the associated support parts 13. The fixing of the two parts to one another can be done, for example, by a weld or a Weld 16 at the end of the support member 13, be effected by a friction weld or by a shrink fit.

In the formwork structure according to FIGS. 4 and 5, a unit 1 of the embodiment shown in FIG. 1 forms the spacer between two formwork walls S1 and S2, on which the supporting parts 3 bear directly. It is also possible to add a thin intermediate layer, cap or the like. to be provided at the plant end of one or both support parts. As indicated by dash-dotted lines in Fig. 4, the anchor rod 2 can additionally be provided with a water barrier in the form of a plate 14 which e.g. is attached to the anchor rod by welding. In the left half of Figure 4, the support part 3 is shown in section, so that the blind hole with the thread 9 for the anchor rod 2 and the blind hole with the thread 7 for the tie rod 17 can be seen.

Solid wall girders T rest on the outside of formwork walls S1 and S2. U-profile supports P are attached to their outer sides, against which a plate wing nut 15 is supported. This is screwed onto a tie rod 17, which has the same thread 5 as the anchor rod 2. The arrangement of the parts is the same on the other side of the formwork. The tie rod 17 is screwed into the screw thread 7 of the support part 3. The formwork is tensioned with the plate wing nuts 15.

Instead of solid wall girders and U-shaped girders, other common parts can of course also be used to support the formwork, such as squared timbers and crossbeams or the like.

A modified embodiment of a support part 21 is shown in FIGS. 6 and 7. There is also a front collar 8, the outside of which gives the end face 4 for abutment against a formwork wall. The part of the support body 21 which adjoins the collar 8 has two strip-shaped projections 22 at diametrically located locations. The screw-in thread for a tensioning element in the blind hole of the supporting part which is open towards the front side 4 is also designated here by the number 7. To the other side there is a blind hole with a thread 9 for screwing in the anchor rod.

In the case of the embodiment according to FIGS. 8 and 9, features that correspond to the embodiments already described are designated with the same reference numbers as there. The supporting part 23 has a square shape 24 in its main body adjoining the collar 8, as particularly shown in FIG. 9.

Finally, FIG. 10 shows a further exemplary embodiment of a support part 25 with a screw thread 7 for a tie rod and a screw thread 9 for an anchor rod. The front part 4 of the supporting part intended for bearing against the formwork wall has a larger diameter than the rear part, so that a correspondingly large contact surface results. The transition between the two areas is appropriately conical, as indicated by the angle 26.

After stripping, the end faces 4 of the support parts are normally flush with the outside of the concrete surface. If desired, the blind hole with the screw thread 7 can be closed by a plug. This can be an elastic plug of known type, which can be pressed into the threaded bore 7. FIGS. 11 and 12 show a stopper 30 which can be made of plastic or also corrosion-resistant metal and which has a thread 31 which fits into the screw-in thread 7 of the supporting part in question, which is slightly countersunk at its beginning, so that the stopper 30 screwed into it. The front of a head part 32 of the plug 30, which is bevelled in the manner of a countersunk screw, comes to lie flush with the end face 4 of the support part. A slot 33 or another type of key attack can be provided in the head part 32.

In Figure 3, a particularly advantageous embodiment of a thread is shown in an enlarged sectional view, as it is for the clamping elements, e.g. the tension rods 5 in Figures 4 and 5, and for the screw thread 7 in the support parts, but is also suitable for an anchor rod, at least at the ends screwable into the support parts.

3 has a base region 41, the contour of which is at least predominantly an arc 42 with the radius R, and a head region 43, the contour of which is predominantly formed by a straight line 44. Between the base area and the head area there is a transition area 45, which is at least partially delimited by a circular arc contour 46 with the radius r.

A head width is designated with the letter B. It results from the intersection of tangents 48 at turning points 47 or small straight intermediate parts between the contours 42 and 46 with extensions of the straight line 44 of the head contour. The angles between the tangents 48 and radius lines are designated by the letter b. The thread has an outer diameter D and a core diameter d with a profile height h as the difference between them. The thread has a pitch t.

Advantageous values for the execution of such a thread are given below:
t = 6.0 mm
R = 1.4 mm
r = 1.0 mm
W = 2.6 mm
b = 30 °.

For many applications, Outside diameter D of about 17 mm, 23 mm and 29 and core diameter d of 14 mm, 20 mm and 26 mm are particularly favorable.

Such a thread is to a high degree insensitive to unfavorable effects, can be screwed easily and can absorb high loads. It is therefore particularly suitable for clamping elements, in particular of the type explained above, but can also be used advantageously for other parts in concrete construction.

All of the features mentioned in the above description or shown in the drawing, if the known prior art permits, should be regarded as falling within the scope of the invention on their own or in combinations.

Claims (25)

1. System for use in the construction of concrete formwork, wherein two the cavity for filling the concrete on opposite sides delimiting formwork walls by spacers, formed by anchor rods with a screwing of tensioning elements in the form of bolts, bars, or the like. from the outside of the formwork parts at the ends are supported, characterized in that the spacers each consist of an anchor rod (2, 12) and of two corrosion-resistant or rustproof metal material or provided with a corrosion-resistant material, blind hole-like screw-in thread (7) for supporting parts (3, 13, 21, 23, 25) having tensioning elements at the ends of the anchor rod (2, 12) as ready-to-use units (1, 11) with firm connection of the supporting parts (3, 13, 21, 23, 25) are produced with the anchor rod (2, 12) and that the supporting parts (3, 13, 21, 23, 25) or the like for abutment on the inner sides of the formwork walls or on abutments used in these. have suitable end faces (4) which have a fixed distance (A) from one another as a result of the manufacture of the unit (1, 11), in particular a distance equal to the desired distance of the formwork walls from one another, the units (1, 11 ) after the concrete poured into the formwork has set completely. 2. System according to claim 1, characterized in that the supporting parts (3, 13, 21, 23, 25) consist of corrosion-resistant or stainless steel. 3. System according to claim 1 or 2, characterized in that the support parts (3, 13, 21, 23, 25) are made by casting. 4. System according to any one of claims 1 to 3, characterized in that the support parts (3, 13, 21, 23, 25) have a rough surface at least on their circumference. 5. System according to any one of claims 1 to 4, characterized in that the supporting parts (3, 13, 21, 23) have an outer shape deviating from a rotationally symmetrical shape. 6. System according to one of claims 1 to 5, characterized in that the anchor rod (2) is provided at least at its ends with a thread (5) or a thread-like profile. 7. System according to any one of claims 1 to 6, characterized in that the anchor rod (2, 12) consists of reinforcing steel. 8. System according to claim 6 or 7, characterized in that the supporting parts (3, 21, 23, 25) are provided with threaded bores (9) for screwing in the anchor rod (2). 9. System according to any one of claims 1 to 5, characterized in that the anchor rod (12) is a substantially smooth rod. 10. System according to one of claims 1 to 9, characterized in that the anchor rod (2, 12) is provided with at least one locking element (14) for water. 11. System according to any one of claims 1 to 10, characterized in that the supporting parts (13) with the anchor rod (12) are connected by welding. 12. System according to one of claims 1 to 10, characterized in that the supporting parts (3) with the anchor rod (2) by pressing, squeezing or the like. are connected. 13. System according to any one of claims 1 to 10, characterized in that the supporting parts (13) on the anchor rod (12) are fastened by shrink connections. 14. System for use in the construction of concrete formwork, in which threaded clamping elements are screwed into support parts or the like at the ends of an anchor rod. located, in particular system according to one of claims 1 to 13, characterized in that threads with a pitch of 6 mm are provided as the screw-in thread (7) of the support parts (3, 21, 23, 25) and for clamping elements (17) which can be screwed into them . 15. System for use in the construction of concrete formwork, in which threaded clamping elements are screwed into support parts or the like at the ends of an anchor rod. located, in particular system according to one of claims 1 to 14, characterized in that for clamping elements (17) which can be screwed into the supporting parts (3, 21, 23, 25), a thread with fol features is provided, to which the screw-in thread (7) is designed to match:
- The thread profile seen in longitudinal section has a base region (41), a head region (43) and a transition region (45) between the two,
- The contour (42) of the base region (41) is at least predominantly an arc,
- The contour of the head region (43) is at least predominantly a straight line (44) running parallel to the thread axis,
- The transition region (45) has at least partially an arcuate contour (46). 16. System according to claim 15, characterized in that the radius (R) of the circular arc contour (42) of the base region (41) is approximately 1.4 mm. 17. System according to claim 15 or 16, characterized in that the radius (r) of the circular arc contour (46) of the transition region (45) is approximately 1.0 mm. 18. System according to any one of claims 15 to 17, characterized in that a head width (B), measured between the intersection of tangents (48) at turning points (47) or such corresponding intermediate parts of the profile with extensions of the straight line (44) of the head region (43), is about 2.6 mm. 19. System according to any one of claims 15 to 18, characterized in that the respective angle (b) between a tangent (48) to a turning point (47) or a corresponding intermediate section of the profile and a radius line is approximately 30 °. 20. System for use in the construction of concrete formwork, in which threaded clamping elements are screwed into support parts or the like at the ends of an anchor rod. located, in particular system according to one of claims 1 to 19, characterized in that threads with an outer diameter (D) of approximately 17 mm or 23 mm or 29 mm are provided for the clamping elements (17). 21. System for use in the construction of concrete formwork, in which threaded clamping elements are screwed into support parts or the like at the ends of an anchor rod. located, in particular system according to one of claims 1 to 20, characterized in that threads with a core diameter (d) of about 14 mm or 20 mm or 26 mm are provided for the clamping elements (17). 22. System according to one of claims 1 to 21, characterized in that the anchor rod (2) is provided with the same thread (5) as the clamping elements (17). 23. System according to one of claims 1 to 22, characterized by a plug (30) or the like which can be inserted into the screw-in thread (7) of at least one support part (3, 21, 23, 25). 24. System according to claim 23, characterized in that the plug (30) is provided with a thread (31) which fits into the screw-in thread (7). 25. System according to claim 23 or 24, characterized in that the plug (30) consists of stainless metal material.

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