Concrete Compaction Device with Measurement of Compaction Progress

Abstract

A concrete compaction device includes a vibrator housing for immersion in flowable concrete, and an unbalance exciter which is driven by an electric motor and which is arranged in the vibrator housing. A current detection device detects the electric current absorbed by the electric motor. Ann evaluation device determines an operating state of the concrete compaction device based on the electric current that is currently detected. The operating state is selected from the group consisting of: positioning of the vibrator housing in the air, immersion of the vibrator housing in the concrete, performance of a compaction process with the vibrator housing immersed in the concrete, and emersion of the vibrator housing from the concrete. The evaluation device is configured to recognize all of these operating states.

Claims

1. A concrete compaction device, comprising: a vibrator housing that is configured to be immersed in flowable concrete; an unbalance exciter which is driven by an electric motor and which is arranged in the vibrator housing; a current detection device that is configured to detect an electric current absorbed by the electric motor; and an evaluation device that is configured to determine an operating state of the concrete compaction device based on the electric current that is currently detected by the current detection device; wherein the operating state is selected from the group consisting of: positioning of the vibrator housing in the air; immersion of the vibrator housing in the concrete; performance of a compaction process with the vibrator housing immersed in the concrete; emersion of the vibrator housing from the concrete; and wherein the evaluation device is configured to recognize all of the operating states of the group of operating states.

2. The concrete compaction device according to claim 1, wherein the evaluation device can recognize the following additional operating states: the electric motor being switched off; the electric motor and/or the unbalance exciter being defective.

3. The concrete compaction device according to claim 1, wherein the current detection device is configured to detect, in addition to the current, an electric voltage applied to the electric motor.

4. The concrete compaction device according to claim 1, wherein the current detection device is configured to detect the current with a sampling interval; and wherein the sampling interval is less than 5 seconds.

5. The concrete compaction device according to claim 1, wherein the evaluation device is configured to determine the respective operating state taking into account the respective currently detected electric current and/or a respective determinable current gradient.

6. The concrete compaction device according to claim 1, wherein an interpretation device is provided for interpreting the current flow when an operating state performance of a compaction process is recognized; the interpretation device is configured to evaluate a current gradient for interpreting the current flow; and wherein an approach of the current gradient to a zero value is considered a criterion for compaction progress.

7. The concrete compaction device according to claim 6, wherein a limit value for the approach of the current gradient to the zero value is specified; and wherein a signal device is provided and is configured to generate a signal for an operator upon the reaching of the limit value by the current gradient.

8. The concrete compaction device according to claim 1, further comprising a current supply line that is configured to supply the electric current to the electric motor.

9. The concrete compaction device according to claim 1, wherein a power source for the electric motor comprises an electric energy storage device and/or a power grid.

10. The concrete compaction device according to claim 1, wherein the electrical energy storage device comprises control electronics; and wherein the current detection device and/or the evaluation device and/or the interpretation device are coupled to the control electronics.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] These and other advantages and features of the invention are explained in more detail below by way of examples with the aid of the accompanying figures. Wherein:

[0028] FIG. 1 shows an internal vibrator in schematic representation as a concrete compaction device according to the invention; and

[0029] FIG. 2 shows an example of the change in current draw as a function of the different operating states of a concrete compaction device.

DETAILED DESCRIPTION

[0030] FIG. 1 shows a schematic representation of a concrete compaction system with an internal vibrator 1 and an energy device 2.

[0031] The internal vibrator 1 has an operating hose 3, at one end of which a vibrating head 4 serving as a housing is attached. Inside the vibrating head 4, an electric motor 5 is provided which drives an unbalance exciter 6 in rotation. The unbalance exciter 6 can be, for example, an unbalance shaft on which an unbalance mass is mounted eccentrically so that, when the unbalance shaft rotates, oscillations are generated which are introduced into the concrete to be compacted via the outer wall of the housing of the vibrating head 4. The construction of such a vibrating head 4 with electric motor 5 and unbalance exciter 6 is known in itself.

[0032] In a variant that is not shown, but which is also known per se, the electric motor 5 is not arranged in the vibrating head 4 but rather in its own housing, spatially separated from the vibrating head 4. In this case, a flexible shaft extends between the electric motor 5 and the unbalance exciter 6 arranged in the vibrating head 4, by means of which flexible shaft the torque of the electric motor 5 can be transmitted to the unbalance exciter 6. The flexible shaft is surrounded by the operating hose 3, which can also be used to guide the vibrating head 4.

[0033] The operating hose 3 shown in FIG. 1 can have a length of several meters so that the operator can hang the vibrating head 4 in the concrete to be compacted over a greater distance during compaction work. FIG. 1 is not to scale and does not reflect the actual length of the operating hose 3.

[0034] A switching device 7 is attached to the end of the operating hose 3 opposite the vibrating head 4, by means of which switching device the electric motor 5 can be switched on and off. The switching device 7 can also serve as a coupling point for a power line 8 (power cable). The electrical leads of the power line 8 are routed inside the operating hose 3 to the vibrating head 4, so that the operating hose 3 also takes on the function of a protective hose. At the end of the power line 8 opposite the switching device 7, a plug, not shown in FIG. 1, may be provided in a manner known per se.

[0035] The connector may be plugged into the energy device 2. In the example shown in FIG. 1, essential parts of the energy device 2 can be arranged on a carrying device which is not shown, which carrying device can be carried by a user, for example, on their back, by means of carrying straps, similar to a backpack. In this case, the carrying device may comprise a carrying frame that reliably supports the components attached to it. This is also described, for example, in DE 10 2018 118 552 A1. The energy device 2 comprises a rechargeable battery 9 as an electrical energy storage device. The rechargeable battery 9 can be switched out when exhausted and replaced with a fresh rechargeable battery 9.

[0036] Instead of the rechargeable battery 9, it is also possible to provide an electrical supply via the public power grid or a power network existing at the construction site.

[0037] Furthermore, a converter 10 can be part of the energy device 2, which in particular converts the current drawn from the rechargeable battery 9 with regard to voltage and frequency in a manner suitable for the electric motor 5. This converted current is then supplied by the converter 10 to the electric motor 5 via the power line 8.

[0038] Symbolically, a current detection device 11, an evaluation device 12 and an interpretation device 13 are also provided on the energy device 2. These components can also be located elsewhere on the internal vibrator. However, their arrangement in the vicinity of the rechargeable battery 9 or alternatively of the converter 10 lends itself well in order to, there, precisely detect and interpret the current drawn by the electric motor 5.

[0039] The current detection device 11, the evaluation device 12. and the interpretation device 13 need not be physically separate components. Rather, they may also be arranged in the rechargeable battery 9 or in the battery management system of the rechargeable battery 9, or in the converter 10, or elsewhere. By way of example, the evaluation device 12 and the interpretation device 13 can also be spatially arranged elsewhere, for example, as a software application on a smartphone carried by the operator of the internal vibrator. In this case, a communication link or communication interface must be provided to transmit the current values detected by the current detection device to the evaluation device 12.

[0040] The current detection device 11 is used to detect the electric current absorbed by the electric motor 5. It is possible to detect the current in short sampling intervals.

[0041] The measurement results of the current detection device 11 are passed on to the evaluation device 12, which can detect an operating state of the internal vibrator based on the then currently detected electric current (current values and current flow or alternatively current gradient), as explained below with reference to FIG. 2.

[0042] The interpretation device 13 is intended to interpret the current flow during a compaction process. In particular, the interpretation device 13 is intended to recognize and classify the compaction state during the compaction process.

[0043] When the interpretation device 13 determines that the concrete is currently sufficiently compacted, a signal device, not shown, can be used to signal the operator of the internal vibrator 1 to stop compaction at the corresponding location and continue compaction at another location.

[0044] Information relating to the state of compaction may be communicated to the operator in various ways. For example, the corresponding data can be displayed to the operator via assistance systems, for example, by applications installed on smartphones. In addition, logging of the measurement results for later documentation is also readily possible.

[0045] By way of example, FIG. 2 shows the flow of the current drawn by the electric motor 5 over time during various operating states of the internal vibrator 1. The respective current values can be detected by the current detection device 11 with short sampling intervals.

[0046] During phase a, the internal vibrator runs in the air and is not immersed in the concrete (idling phase, operation of the electric motor at no load, positioning of the vibrator housing in the air). In this phase, the absorbed current is constantly low.

[0047] During immersion of the vibrator housing in the concrete (phase b), the current draw increases and reaches a detectable maximum.

[0048] If the internal vibrator subsequently dwells in the concrete (compaction process), the concrete is compacted in the effective range of the vibrating head 4 (phase c). A partially decreasing current flow can be recognized, with a negative current gradient.

[0049] On the basis of the changing current gradients (current drop), the progress of the compaction process can be concluded by the evaluation device 12 in conjunction with the interpretation device 13. The further the compaction process progresses, the flatter the curve progression becomes, which is to say the current gradient approaches zero value. In this, the current absorbed always remains greater than in the idling phase in the air (phase a), so that the states of idling (phase a) and immersed or alternatively compaction (phase c) can always be clearly distinguished from one another.

[0050] When the vibrating head 4 emerses from the concrete (phase d), a brief increase in current can be observed due to the change in position of the vibrating head 4. Subsequently, the current absorbed falls back to the value corresponding to no-load operation as soon as the internal vibrator is in the air again. Finally, the current draw changes again to the no-load phase (phase e).

[0051] In particular, in the case of a portable energy device provided in a backpack system with an energy storage device that can be used to operate internal vibrators, measurement devices, for example, in the battery control electronics, are usually already present with which the input power can be measured in the form of current and voltage for operating the internal vibrators. Additional sensor technology, in particular, in the vibrating head or the protective tube, is not required.

[0052] Due to the high measurement accuracy and sampling rate, it is possible to infer from the current flow the operating state (no-load, immersion, dwell, emersion) and the compaction progress of the internal vibrator in the concrete. To determine the respective operating state, the measured values or alternatively their curves and changes are compared with known values or, alternatively, patterns.

[0053] The measurements can be carried out in a suitable manner for rechargeable battery-powered internal vibrators, but also for mains-powered internal vibrators.