EP1722948B1 - Modul for installation in a device for compressing concrete during the manufacture of concrete parts - Google Patents

Abstract

The invention relates to a device for compressing concrete during the manufacture of concrete parts. Said device comprises a supporting structure (1), a formwork device (2) which is maintained by the supporting structure (1) and a vibration decoupling device (3) which is arranged between the supporting structure (1) and formwork device (2). The vibrations required to compress concrete are produced by a vibration device (4) acting directly upon the formwork device (2). In order to reduce noise emission, the mass of the supporting structure (1) is selected in such a way that the intrinsic frequency of a system consisting of the supporting structure (1) and vibration decoupling device (3) is lower than the excitation frequency of the vibration device (4). Preferably, the formwork device (2), vibration decoupling device (3), vibrators (4) and all electrical feed lines (8) and connections (10) are premounted, forming a module which can then be mounted on the supporting structure (1).

Description

The invention relates according to the preamble of claim 1, a module for installation in a device for compacting concrete in the manufacture of concrete parts.

In the manufacture of precast concrete elements, the formwork elements in the concrete works are usually placed on vibrating tables, which serve to compact the concrete used for shaping using the formwork elements. Such a vibrating table usually consists of a supporting structure made of steel beams and serving as a table top or formwork skin steel, wood or plastic plate (formwork device), which is held by the support structure. The vibrating tables are equipped with an exciter device in the form of a plurality of vibration exciters, in particular external vibrators, which are distributed over the support structure and can vibrate the supporting structure consisting of the steel carriers and thus also the formwork device. After the construction of the other formwork elements on the vibrating table top and the pouring of the fresh concrete in the formwork elements and in this often inserted reinforcements the vibration exciters are set in motion, which form complex waveforms in the support structure and in particular in the vibrating table top, the result lead to a compression of the concrete. The support structure supporting the vibrating table top is stimulated by the external vibrators mounted there as well as the table top. As a result, impacts occur between parts of the support structure and complex airborne transmission and propagation that can seriously affect the working conditions of the workforce.

In order to reduce especially the high sound level in precast concrete plants when using vibrating tables operated with external vibrators, it is from the DE 196 31 516 A1 known to mount the vibration exciter, namely the external vibrators, directly to the actual formwork, so on the table surface. The formwork is by a vibration decoupling device, namely elastic components, such. As springs, rubber elements or a foam layer from which it uncouples the supporting structure. This reduces the required vibration energy and reduces the vibrations of the support structure. The result is a significantly reduced noise emission of the device during concrete compaction.

The support structure is usually assembled from a plurality of steel beams, on which then the vibration decoupling device and finally the formwork device is attached. This requires a considerable effort on site when mounting the device.

In the EP 1 293 314 A2 a device for the compaction of concrete in the manufacture of concrete parts is described. When adjusting the excitation frequency and the excitation force, the natural oscillations of the system are taken into account.

In the DE 34 27 780 A1 discloses a module for installation in a device for compacting and producing precast concrete parts, according to the preamble of claim 1, in which a formwork surface is elastically supported. The operating frequency of a Schwingungserrregers can be adjusted so that it is close to a natural frequency of the scarf surface.

From the DE 69 26 530 U is a vibrating table for compacting concrete samples is known, in which between the table top and the substrate vibration metal buffers are provided.

In the JP 09234714 A a device for concrete part production is shown in which a vibration exciter can be connected to a formwork device with a power supply.

The invention has for its object to improve a known from the prior art device for compacting concrete in the manufacture of concrete parts in terms of noise emission and installation costs.

The object is achieved by a module according to claim 1 and an apparatus according to claim 10. Advantageous developments of the invention are defined in the dependent claims.

An apparatus according to the invention for compacting concrete in the manufacture of concrete parts has a supporting structure, a formwork device held by the supporting structure and a vibration decoupling device provided between the supporting structure and the formwork device. At least one vibration exciter, z. B. an external vibrator, is provided such that it acts directly on the formwork device. The device is characterized in that an excitation frequency of the vibration exciter is not in the range of a natural frequency of a system consisting of the support structure and the vibration decoupling device.

In general, the supporting structures in such devices for concrete compaction with respect to the excitation frequency of the vibration exciter are flexible. It has been found that despite the use of the vibration decoupling device (eg with spring elements or a foam layer) for decoupling the excited shuttering device, the supporting structure is excited to oscillate when natural frequencies (resonance frequencies) are excited. having in the region of the excitation frequency of the vibration exciter. The result is unwanted noise emissions. By aiming to separate the exciting frequency of the vibrator and the natural frequency of the system consisting of the supporting structure and the vibration decoupling device, such interaction can be avoided.

For this purpose, initially selected for the concrete compaction advantageous excitation frequency for the vibration exciter. The support structure must then be designed such that its resulting from the mass of the support structure and the spring stiffness of the vibration decoupling device natural frequency is as far away from the exciter frequency.

It is particularly advantageous if the excitation frequency is greater than the natural frequency of the system consisting of the support structure and the vibration decoupling device. In particular, the excitation frequency should be at least twice as large as the natural frequency in order to ensure sufficient decoupling.

The idea underlying the invention is to increase the gain of the overall system, d. H. the ratio of output amplitude (amplitude of vibration of the support structure) and input amplitude (exciter amplitude, vibration amplitude of the formwork device), as low as possible to keep. If the excitation frequency is significantly higher than the natural frequency of the supporting structure, the amplification factor approaches zero, i. h., That the support structure is mechanically decoupled. To the extent that the support structure is decoupled from the vibration excitation and thus does not resonate, the noise emission is reduced.

In order to obtain a sufficient decoupling by separation of the exciter frequency from the natural frequency, it is particularly advantageous if the support structure is provided with the greatest possible mass. The larger the mass of the supporting structure, the lower is its natural frequency. By "largest possible mass" is thus to be understood a mass that considers the expert due to the local conditions, the construction and cost and the size of the formwork device for reasonable. In any case Attempts should be made to choose the mass of the supporting structure as large as possible, taking advantage of the boundary conditions. Since the excitation frequency - as stated above - essentially determined by the desired concrete compaction, the excitation frequency can hardly be changed. Thus, above all, a change in the natural frequency of the support structure is desirable.

In order to equip the support structure with a correspondingly large mass, it is particularly advantageous if the support structure is essentially formed by a concrete base. The concrete is not only heavy but relatively cheap in relation to its mass. It is thus easily possible to provide the support structure with a sufficient mass.

In a particularly advantageous embodiment of the invention, the support structure is decoupled from the ground carrying them vibrationally. For example, a soft intermediate layer may be provided between the support structure and the floor. In this way it is possible, the support structure of the surrounding building structures, eg. As the floor, the walls and the foundations to decouple. An additional noise reduction is possible.

While in the prior art, for. B. in the device of the DE 196 31 516 A1 , The formwork device is inserted in the form of a viscoelastic intermediate layer only between the formwork device (shuttering skin) and the support structure, in the module according to the invention, the vibration decoupling device is attached to the formwork device. Thus, it is possible to completely pre-assemble the entire module in the factory, so in particular also except the vibration decoupling device already the vibration exciter on the formwork device to fix. In this way, the effort in final assembly in precast concrete plant can be significantly reduced.

The electrical leads for the vibration exciters are already completely attached to the formwork device. The leads can z. B. between the Schwingungsentlcopplungseinrichtung and the formwork device and thus be held by the vibration decoupling device to the formwork device.

It when the vibration decoupling device comprises a foam layer and the electrical leads extend within the foam layer is particularly advantageous. The leads are then decoupled vibrationally from the formwork device, although they are supported by this.

In a preferred embodiment of the invention, an electrical connection device is attached to the formwork device, so that the electrical leads are connected to an electrical supply network, for. As a available in precast concrete plants 250 V or 42-volt network can be coupled. For this purpose, it is expedient if a central connector is provided on the connection device in order to couple the connection device to the supply network. Part of the supply network can also be a mobile power supply device, eg. B. be a mobile frequency converter.

The electrical connection device should also be decoupled from the formwork device in terms of vibration in order to avoid unnecessarily high mechanical stress.

The module according to the invention can thus be fully assembled in the factory including the electrical equipment. At the receiver, ie in the precast concrete factory, the module must then only on a support structure there existing, for. B. a concrete base are placed. The only electrical connection work on site is then that the central connector is connected to the supply network by simply Einekken in a socket. The module according to the invention thus enables a so-called "plug-and-play solution" with which the assembly costs can be significantly reduced on site of the customer.

These and other advantages and features of the invention are explained in more detail below by means of an example with the aid of the figure. The single FIGURE shows an inventive device for compacting concrete in three schematic partial sections a) to c).

The device according to the invention is often referred to in practice as a vibrating table. On the vibrating table shuttering elements, not shown in the figure can be constructed, which serve to shape the concrete part to be manufactured. The formwork elements are arbitrarily to combine in a known manner, so that at this point a more detailed description is unnecessary.

Part of the vibrating table is a support structure 1, which holds a formwork device 2. As a formwork device 2 here is the table surface or table top or shuttering skin to be considered, which is thus also part of the overall formwork (consisting of table top / shuttering device 2 and the other formwork elements described above). Above the formwork device 2, the fresh concrete is filled.

Between the shuttering device 2 and the support structure 1 serving as a vibration decoupling foam layer 3 is provided. The foam layer 3 preferably represents a viscoelastic layer, the z. B. may also consist of a gradient material, which on the one, the formwork device 2 side facing relatively soft elastic to favor the propagation of vibrations in the formwork device 2, and on the other, the support structure 1 side facing damping and plastic Has properties to largely avoid the structure-borne sound transmission to the support structure 1. In principle, however, numerous other materials which enable vibration decoupling are also suitable for the vibration decoupling device. Moreover, it is not necessary that the vibration decoupling device is designed in the form of the foam layer 3. Instead, z. B. also individual rubber elements or spring elements are used.

The foam layer 3 can only be inserted between the support structure 1 and the formwork device 2. However, it is particularly advantageous if the foam layer 3 is glued to the underside of the formwork device 2. This allows pre-assembly already in the factory of the device manufacturer, so that the effort in the final assembly in the precast concrete plant is reduced.

At the formwork device 2 at least one, but preferably a plurality of vibration exciter 4 are mounted on the side facing away from the concrete side. The vibration exciters 4 are preferably external vibrators known per se, the structure and mode of action of which therefore need not be discussed further here.

From the prior art, it is known to assemble the support structure as a static structure of steel beams. In the embodiment of the invention shown in the figure, however, the support structure 1 is designed as a solid concrete base. Steel beams are therefore not available. The concrete base can be produced on site in the precast concrete plant because the fresh concrete required for the production is already present in the precast concrete plant, so that transport of the concrete base or concrete is unnecessary. Thus, the cost of the overall system can be significantly reduced.

The support structure 1 stands on a floor 5 of the building in which the device is constructed. For additional vibration decoupling, a vibration decoupling layer 6 is provided between the support structure 1 and the bottom 5. This may also be a foam layer or a rubber layer, which serves to avoid a transmission of existing in the support structure 1 vibrations on the floor 5 and thus in the building environment. Instead of the vibration decoupling layer 6, it is also possible to use corresponding spring foundations with which a vibration decoupling between the support structure 1 and the base 5 is almost completely possible.

On top of the support structure 1 recesses 7 are provided, in which the vibration exciter 4 can be used. Thus, the vibration exciter 4 are hermetically sealed from the environment, so that the noise emanating from them can not radiate to the environment. If necessary, ventilation or cooling of the drives of the vibration exciter 4 must be ensured.

The excitation frequency to be generated by the vibration exciters 4 is preset due to the desired concrete compaction. Often the exciter drives are already designed so that they automatically reach a suitable speed and thus exciter frequency. The excitation frequency is usually also changeable during operation of the device and is usually between 85 and 100 Hz.

In order to achieve a vibration-decoupling of the support structure 1 from the excited vibration of the formwork device 2, it is desirable according to the invention that the natural frequency of a system consisting of the support structure 1 and the foam layer 3 does not coincide with the exciter frequency of the vibration exciter 4. Rather, the excitation frequency should be significantly greater than the natural frequency, with the ratio between excitation frequency and natural frequency should be above a value of 2.0 lying.

In order to achieve the resulting natural frequency of the support structure 1, it is necessary to equip the support structure 1 with a correspondingly high mass. The natural frequency decreases with increasing mass. It is determined by the root of the quotient of the spring stiffness of the foam layer 3 and the mass of the support structure 1. The support structure 1, ie in particular their mass, is thus designed so that the resulting natural frequencies of the overall system of support structure and vibration decoupling device (foam layer 3rd ) are so far below the excitation frequency, that a good mechanical decoupling, ie a low gain factor is given and the noise emission of the entire device is thereby greatly reduced. In practice, it was possible to achieve a mass for the concrete base of the support structure 1, which grants a natural frequency of 27 Hz. For this purpose, a specific mass for the concrete base of the support structure 1 of about 900 kg / m ^{2 was} realized. Thus, the ratio of excitation frequency to natural frequency in this example is 3, 7, thus significantly above the required value of 2.0.

In the partial section b) of the figure, a section through the device is shown in the electrical leads 8 can be seen. The electrical leads 8 are used for electrical supply to the vibration exciter 4. They are guided directly in the foam layer 3 and are thus fixed by means of the foam layer 3 to the formwork device 2.

The electrical leads 8 can also be attached directly to the formwork device 2. However, the noise reduction is improved when the leads 8 are embedded in the foam layer 3. The fact that the electrical leads 8 are laid within the foam layer 3, they can not cause rattling noises. Additional cable entries in the support structure 1 or cable fixings are not required.

For ease of assembly, the foam layer 3 is provided at the corresponding points with slots 9, in which the electrical leads 8 can be pressed. The leads 8 are then fixed by force and / or positive connection in the adjoining the slots 9 groove.

At the latest with the placement of the formwork device 2 on the support structure 1 and the electrical leads 8 are fixed and can no longer fall out of the slots 9.

At one point of the device, an electrical connection device in the form of a connection box 10 is fastened to the formwork device 2 (partial section c) in the figure). To ensure a vibration decoupling, rubber elements 11 are provided between the junction box 10 and the formwork device 2.

From the terminal box 10 go all the electrical leads 8 for the various vibration exciter 4, wherein the leads 8 are performed in the manner explained above with reference to partial section b).

At the junction box 10, a central connector 12 is provided, on which the entire device can be connected to a present in the precast concrete plant stationary supply network. Instead of the connector 12 are of course other known connection options suitable. As an alternative to the supply network, the connector 12 can also be connected to a mobile power supply device, for. B. be connected to a movable frequency converter.

In order to provide sufficient space for the terminal box 10, a further recess 13 is provided in the support structure 1.

Substantial parts of the device are already pre-assembled in the form of a module when they are delivered to the precast factory. For this purpose, the vibration exciter 4 are already attached to the formwork device 2 together with the foam layer 3. The vibration exciter 4 are completely electrically connected via the leads 8 and connected to the junction box 10, which is also already attached to the formwork device 2 via the rubber elements 11. The module thus forms a fully assembled, in principle functional unit.

It is thus possible with the help of the module to mechanically and electrically pre-assemble almost the entire device according to the invention and in the preassembled state at the customer, d. H. the precast concrete factory. There, the module only has to be placed on the support structure 1, which has been made on site in a particularly simple manner from concrete. After placing the module on the support structure 1, only the power supply to the central connector 12 must be connected. The assembly work for the customer can thus be reduced to a minimum. With the aid of the invention, a "plug-and-play" solution is provided, which is suitable for a drastic reduction of the effort during the installation and start-up of the low-noise vibrating table.

Claims (18)

1. Module for installation in a device for compacting concrete, having

   - a formwork device (2);

   - a vibration decoupling device (3) which is attached to the formwork device (2);

   - at least one vibration exciter (4) which is attached to the formwork device (2); characterised in that the electrical supply lines (8) for the vibration exciter(s) (4) are attached to the formwork device (2) and are held on the formwork device (2) by means of the vibration decoupling device (3).
2. Module as claimed in claim 1, characterised in that the electrical supply lines (8) run between the vibration decoupling device (3) and the formwork device (2).
3. Module as claimed in claim 1 or 2, characterised in that the vibration decoupling device comprises a foam layer (3), and that the electrical supply lines (8) run inside the foam layer (3).
4. Module as claimed in any one of claims 1 to 3, characterised in that an electrical connection device (10) is attached to the formwork device (2) for the purpose of coupling the electrical supply lines (8) to an electrical supply network.
5. Module as claimed in claim 4, characterised in that a central plug-in connector (12) is provided on the connection device (10) for the purpose of coupling to the supply network.
6. Module as claimed in claim 4 or 5, characterised in that the electrical supply lines (8) between the connection device (10) and the vibration exciter (4) are attached completely to the formwork device (2).
7. Module as claimed in any one of claims 4 to 6, characterised in that the electrical connection device (10) is decoupled in terms of vibration from the formwork device (2).
8. Device for compacting concrete during the manufacture of concrete parts,
   characterised in that

   - a module as claimed in any one of claims 1 to 7 is provided, wherein the formwork device (2), the vibration decoupling device (3) and the vibration exciter (4) are completely preassembled to form the module; and that

   - the preassembled module can be placed onto a support structure (1).
9. Device as claimed in claim 8, characterised in that recesses (7) are provided in the support structure (1) for the purpose of receiving the vibration exciters (4).
10. Device for compacting concrete during the manufacture of concrete parts, having

    - a support structure (1);

    - a formwork device (2) which is held by the support structure (1);

    - a vibration decoupling device (3) which is provided between the support structure (1) and the formwork device (2) and having;

    - at least one vibration exciter (4) which acts directly upon the formwork device (2);
    wherein

    - an excitation frequency which is generated by the vibration exciter (4) is a frequency which is advantageous for concrete compaction; and wherein

    - a system consisting of the support structure (1) and the vibration decoupling device (3) is configured in such a manner that its resonance frequency is not in the range of the excitation frequency;
    characterised in that

    - the formwork device (2), the vibration decoupling device (3) and the vibration exciter (4) are combined to form a preassembled module as claimed in any one of claims 1 to 7;

    - the module can be placed onto the support structure (1).
11. Device as claimed in claim 10, characterised in that the resonance frequency of the system consisting of the support structure (1) and the vibration decoupling device (3) is less than the excitation frequency of the vibration exciter (4).
12. Device as claimed in claim 10 or 11, characterised in that the resonance frequency is at most half as great as the excitation frequency.
13. Device as claimed in any one of claims 10 to 12, characterised in that the support structure (1) is provided with the greatest possible mass.
14. Device as claimed in any one of claims 10 to 13, characterised in that the support structure (1) is formed substantially by a concrete base.
15. Device as claimed in any one of claims 10 to 14, characterised in that the support structure (1) is decoupled in terms of vibration from a floor (5) which supports it.
16. Device as claimed in any one of claims 10 to 15, characterised in that a soft layer (6) is provided between the support structure (1) and the floor (5).
17. Device as claimed in any one of claims 10 to 16, characterised in that recesses (7) are provided in the support structure (1) for receiving the vibration exciters (4).
18. Device as claimed in any one of claims 10 to 17, characterised in that the vibration decoupling device (3) is attached to the formwork device (2).

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