Patent Application
20050210796
The invention relates to a formwork component (form) with at least one wooden or synthetic formwork board.
In the construction industry, a variety of forms is used to encase an area which is to be poured with concrete, such as a wall or a roof. In the case of formwork for ceilings, the forms may be, for example, a plurality of formwork boards which are positioned horizontally close together, so that, after a containment border is assembled, a ceiling can be poured. There further exist forms that comprise at least one board and a substructure, in the form of one or more girders or square timbers, or a frame, for example. Such structures may be stored, transported, and deployed as integral forms, traditionally by binding them solidly together with the frames or girders.
It is known to attach formwork boards to a substructure, such as several girders, by nails, clamps, or screws. The screws can be screwed into the board from either the reverse side or, alternatively, the front side, with the heads counter-sunk and the surface evenly filled in. It is also known that a form can be glued to a girder.
Methods are also known to repair damage, such as dents or holes to formwork boards. Here, the board is normally milled, and a repair disk is placed in the milled section. This can be achieved by gluing, clamping, nailing, or screwing the disk in place. The methods described, both to fix a board to one or more girders, and to repair a board, involve a long processing time, a short life span of the joint, inadequate surface flatness and smoothness, and inadequate corrosion resistance. Furthermore, re-treatment of the joint is commonly needed.
Known from WO 98/42988 is an appropriate joining element as well as a method to fix the joining elements in a material with pores or cavities. A closed-end bore is located in the elements to be joined, and a joiner pin is placed in the bore. Energy is targetedly applied to the joiner pin so that it plasticizes and macroscopic bonds are formed in the elements to be joined.
The object of the invention is to provide a form with improvements, as regards its connection to a substructure and/or repair, in at least one of the following features: processing time, detachability, durability, surface flatness, surface smoothness, required re-treatment, corrosion resistance.
The solution to this problem is the formwork component described in claim 1.
In accordance therewith, this formwork component comprises at least one wooden and/or synthetic formwork board. At least one thermoplastic element is also provided, which is set in the board and bonded to the wood and/or synthetic material of the board and/or girder. It should be noted in this regard that girder in the sense of the present application refers to any load-carrying or load-supporting component or a component to be connected to the board in any other manner. For example, square timbers and the like can also be used for this purpose.
The thermoplastic element for joining the formwork board to a girder can be in the form of a dowel or some kind of stud, as described in detail below. Alternatively, the thermoplastic element can be a repair insert or a film to attach a repair insert. As noted, the board can be made of wood or synthetic material. It is also possible for the board to comprise a wooden core coated at least in part with a synthetic material. The material combinations described above apply also to a girder to which the board is to be attached. The attachment and/or repair can be carried out in extremely short periods of time in all embodiments. For this purpose, the board may be pre-bored so that the thermoplastic element can be inserted. When attaching a girder to the board, the girder does not have to be pre-bored, although it may be preferable for the girder to be pre-bored as well. The thermoplastic element may be, for example, inserted in the bore or milled section of the board, and then bonded with the board and/or girder.
Ultrasound may be used to bond the thermoplastic element. This leads to at least a partial plasticization on the thermoplastic element, so that the plasticized material thereof at least partially infiltrates pores and/or small cavities in the material of the board and/or girder. When the energy is no longer applied, i.e., for example, the ultrasound application ceases, the thermoplastic element solidifies (hardens) and is thus bonded with the material of the board and/or girder. This is a solid bond and provides for a durable attachment between a board and girder. Furthermore, the thermoplastic element may be utilized in this way to durably bond a repair insert to the board. This also applies to situations in which the thermoplastic element is in itself a repair insert.
Tests have shown that the described method leads to extremely short processing times. Further, a flat and smooth surface may be achieved through a suitable configuration of the thermoplastic element, in which the surface of the latter is aligned with the surface of the board. No re-treatment is necessary with this method, and the bond described leads to impermeability. Ultimately, no elements are made of metal, such as the known clamps, nails or screws, so that the inventive formwork component is less corrodible. It is further noted that especially in the embodiment in which a board is bonded with a girder, detachability can be ensured to advantage. The procedure according to the above-mentioned WO 98/42988, incorporated herein by reference, may be chosen with respect to the method described.
Preferable embodiments of the inventive formwork component are described in the remaining claims.
Although the thermoplastic element may be inserted in the board in any practical manner, it is currently preferable that the board comprises a bore and/or milled section in which the thermoplastic element can be inserted. The bore and/or milled section may be a through-hole section such that an appropriate thermoplastic element may be inserted all the way through the through-hole section of the board, and further into a substructure such as a girder, and there bonded by means of the method described above.
Tests have shown that a stepped-bore is optimal, in combination with a suitably reverse-stepped thermoplastic element, to form a positive joint.
To plasticize the thermoplastic element in order to further develop the bond after hardening has taken place, many methods are possible. It is currently preferable, however, to press the thermoplastic element in utilizing ultrasound. WO 98/42988 is again a reference for details in this method.
In the preferred embodiment in which a board is attached to at least one girder, the thermoplastic element is advantageously a bonding element.
In particular, the thermoplastic element may be advantageously in the form of a dowel to attach the board to the girder.
In this case, it has also proven to be advantageous to form the dowel with regions of varying diameters. In other words, the dowel comprises at least one step along its length, so that the described bond is supported, at at least one step, by a positive joint with a complementary step in the board and/or girder.
In another embodiment, the thermoplastic element may be a repair insert. In other words, when a damaged section of the board is suitably milled, the thermoplastic element is inserted as a repair insert, and plasticized with, for example, ultrasound, so that the described bond is formed. The advantages described above are also applicable here.
In practice, positive results have also been obtained when the thermoplastic element has been designed to align with the surface of the board. Through this, a continuously flat and smooth surface may be guaranteed without re-treatment, so that an equally smooth concrete surface may be formed in an advantageous manner.
Another preferable embodiment is currently one in which the thermoplastic element is in the form of a film, in other words, an extremely thin disk. The thermoplastic element of this embodiment can be used to secure other elements in that it is, once again, supplied with energy such as ultrasound, and is bonded to the wood and/or synthetic material of the board and/or girder as well as to the material of the aforementioned other element.
In particular, the thermoplastic element of this embodiment may be attached to a repair insert which is aligned with the surface of the board. This attachment can, preferably concurrently with the attachment to the board, also be achieved with the plasticization and subsequent solidification described above. In this manner, minimal effort is necessary to achieve the above-mentioned advantages during repair of a formwork component.
The invention will now be described in more detail with reference to the embodiments of the invention as shown in the Figures, in which:
In the method for producing the inventive formwork component 10, the described bore 22 is machined into the board 14, and the dowel 16 is then inserted through the bore 22 while being subjected to ultrasound so that it infiltrates the material of the brace 20 of the girder 12. Due to the application of ultrasound, the thermoplastic dowel 16 is plasticized at least in part, so that material thereof infiltrates cavities and imperfections in the board and/or girder which may be made of wood and/or synthetic material, thus forming a bond after solidification therein. Through this, the board 14 is secured to the girder 12. This attachment can be formed on further points and/or with further girders.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 014 944.5 | Mar 2004 | DE | national |
