[0001] The invention relates to a fastening plate comprising a plate- like part and anchorage parts fastened thereto, the fastening plate being in- tended to be arranged in concrete before the concrete hardens and further to be fastened to the concrete by means of the concrete hardening, whereby each anchorage part is fastened to the plate part by means of a threaded connection provided by a threaded part at the anchorage part and a hole with internal threads and provided in the plate part.

[0002] Various fastening plates are nowadays well-known in the construction industry. Fastening plates are elements intended to be fastened to concrete before the concrete hardens. Fastening plates are made of a suitable material, such as steel material. According to the prior art, anchorage parts are fastened to the plate part in a suitable way, such as by welding them to the plate surface or to a hole extending through the plate. Threaded connections have also been used for fastening anchorage parts to the plate part. The fastening plates are arranged in concrete in such a manner that the anchorage parts protrude into the concrete and the outer surface of the plate part lies on the surface of the concrete. The fastening plates adhere to the concrete during the hardening of the concrete.

[0003] The purpose of a fastening plate is to achieve a structure allowing the transfer of forces and loads induced by different structures to concrete. The aforementioned structure is achieved by fastening structural fastening means to the plate part on the surface of the concrete after the concrete has hardened. The fastening may be performed by welding directly to the plate part, for example. Thus, different structures may be fastened to the structural fastening means mentioned above and it is possible to achieve a structure that transfers forces and loads induced by different structures via the fastening plate to the concrete.

[0004] There are some practical problems with the prior art solutions. In case of using prefabricated fastening plates, in which the anchorage parts are fastened by welding, the problem is that it is in many cases difficult and sometimes even impossible to mount the plates in their places in the concrete structure, if the concrete structure has a great number of reinforcements. Another disadvantage of a welded connection is also that the anchorage parts welded to the surface cause additional stress on the plate part which, in turn, makes additional demands on the plate part.

[0005] In cases where the welded structure causes problems, it is naturally possible to use fastening plate solutions, in which the anchorage parts are fastened to the plate part by a threaded connection. A drawback of this solution is that, under construction site conditions, it is often difficult to ensure the proper operation of the threads of the threaded connection. A poor fastening of the anchorage parts may endanger the entire fastening process of the fastening plate to the concrete.

[0006] The purpose of the invention is to provide a fastening plate, by which the prior art disadvantages can be eliminated. This is achieved by a fastening plate according to the invention. The fastening plate of the invention is characterized in that the anchorage part comprises a collar part extending from the threaded part and comprising a first flange part and a second flange part at a distance therefrom in the longitudinal direction of the anchorage part, whereby a groove is formed between the first and the second flange part, that when the threaded part of the anchorage part is screwed in the internal threads of the hole, the first flange part is arranged to be pressed against the surface of the plate part around the hole, and that when the first flange part is pressed against the surface of the plate part, it is arranged to yield and cover the groove between the first and the second flange part.

[0007] The invention provides above all the advantage that it provides a visual aid for controlling the formation of a threaded connection; in other words, the invention makes it is easy and simple to ensure the sufficient tightness of the threaded connection at construction sites and, thus, facilitates the implementation of anchorage under construction site conditions. The invention even allows screwing in the anchorage parts to their places inside a reinforcement. It is also much easier to transport the separate plate parts and anchorage parts to the construction site and handle them during the transport and at the construction site than in cases where a pre-welded fastening plate structure is used. An advantage of the invention is also its simplicity, which makes the adoption of the invention advantageous.

[0008] The invention will be explained in the following in more detail by means of the example described in the attached drawing, in which Figure 1 shows a perspective principle view of a fastening plate attached to a concrete structure and structural fastening means fastened to the fastening plate,

Figure 2 shows a principle view of the fastening plate of the inven- tion from the side,

Figure 3 shows a principle view of the fastening plate according to Figure 2 from another direction, and

Figure 4 shows a detail A of Figure 2 on a larger scale.

[0009] Figure 1 shows the principle of a fastening plate attached to a concrete structure 1. The fastening plate comprises a plate part 2 and anchorage parts 3. Structural fastening means 12 are fastened to the plate part 2. The anchorage parts 3 may be fastened to the plate part 2 by welding or a threaded connection, for instance. The fastening plate is arranged in concrete before the concrete dries, whereby it is fastened to the concrete while the con- crete hardens.

[0010] The concrete structure 1 and the structural fastening means 12 are shown in Figure 1 by broken lines. The concrete structure 1 may be any known structure. Accordingly, the structural fastening means may be any structures known per se. For example, different structural elements of a building may be fastened to the structural fastening means 12, whereby forces and loads induced by these structural elements are transferred to the concrete via the fastening plate. These facts are well known to a person skilled in the art, wherefore they are not explained in greater detail herein.

[0011] The plate part 2 may be made of any suitable material, such as a steel plate part. The anchorage parts may be any suitable steel parts. The free ends of the anchorage parts may comprise expansion parts, as shown in Figure 1. However, the aforementioned expansion parts are not necessary but it is quite possible to use anchorage parts without expansion parts. The anchorage parts may be smooth-surface elements or elements with suitable pro- jection surfaces, such as ribbed steel bars.

[0012] For a person skilled in the art, this is fully conventional technology, wherefore it is not explained in greater detail herein.

[0013] Figures 2 to 4 illustrate an embodiment of the fastening plate of the invention. The same reference numerals are used in Figures 2 to 4 as in Figure 1 to refer to the corresponding parts. [0014] In the embodiment of Figures 2 to 4, the anchorage parts 3 are fastened to the plate part 2 by means of a threaded connection. The threaded connection comprises a threaded part 4 provided at the anchorage part 3 and a hole 6 with internal threads 5 provided in the plate part 2.

[0015] According to the essential idea of the invention, the anchorage part 3 comprises a collar part 7 extending from the threaded part 4 and comprising a first flange part 8 and a second flange part 9 at a distance therefrom in the longitudinal direction of the anchorage part. The collar part 7 is arranged in such a manner that it forms an extension of the threaded part so that the collar part is before the threaded part 4 when viewed from the free end of the anchorage part 3 towards the plate part 2. A groove 10 is formed between the first and the second flange part. When the threaded part 4 of the anchorage part is screwed in the internal threads 5 of the hole 6, the first flange part 8 is arranged to be pressed against the surface of the plate part 2 around the hole 6. When the first flange part 8 is pressed against the surface of the plate part 2, it is arranged to yield and cover the groove 10 between the first and the second flange part.

[0016] The first and the second flange part are preferably continuous circular parts extending around the anchorage part 3 as a continuous structure. However, this is not necessary, but instead, the flange parts or at least the first flange part may also be elements having different star-shaped or pinion-like shapes.

[0017] In the embodiment of the figures, a bevelled surface 11 is provided on the surface of the plate part 2 around the hole 6. The bevelled sur- face 11 is arranged to slant towards the longitudinal middle axis of the hole 6. This is shown clearly in Figure 4. The bevelled surface 11 is arranged to extend around the hole 6 as a continuous surface.

[0018] Hence, the idea of the invention is that when the anchorage part 3 is screwed in and tightened to the hole 6, the first flange part 8 is pressed against the surface of the plate part 2 around the hole 6 at a certain tightening stage, whereupon the first flange part 8 starts to deform, which means that the first flange part 8 yields, i.e. bends away from the surface of the plate part 2 so that the groove 10 is covered at a certain predetermined tightening stage. This leads to a visible securing mechanism that indicates and en- sures in a practical manner the proper fixing of the anchorage part to the plate part 2. The bevelled surface 11 contributes to the deformation of the first flange part so that an advantageous function is provided.

[0019] The groove 10 surrounding the anchorage part 3 is preferably a continuous groove extending around the anchorage part 3. A continuous groove provides the advantage that a structure is achieved, where, with a suitable degree of tightening, the first flange part 8 bends along the entire distance and the whole groove is covered. Such a situation can be easily detected even under difficult construction site conditions.

[0020] The above example of the invention is not intended to limit the invention in any way, but the invention may be varied entirely freely within the scope of the claims. For example, the shape and size of the plate part may vary freely according to each situation. Accordingly, the number and dimensions of the anchorage parts may vary freely according to the situation, etc.