The invention relates to a hand-guided ground compaction machine, in particular a vibratory tamper or a vibration plate compactor.
Generic vibratory tampers are known, for example, from EP 2 434 053 B1, and generic vibration plate compactors are known, for example, from DE 10 2012 017 777 A1. They are typically employed in asphalt and earth works to increase the stability of subsoils. To this end, they include a superstructure and a drive device arranged on said superstructure and having at least one drive shaft. The drive device is usually a combustion engine, for example a gasoline, diesel or liquefied gas type combustion engine. Moreover, the generic hand-guided ground compaction machines include a substructure having a compaction plate driven by said drive device. The compaction plate may, for example, be part of a tamper foot in the case of vibratory tampers, and may be a vibratory plate in the case of a vibration plate compactor. The drive device normally drives an oscillation or vibration exciter, which, for example, sets the tamper foot of a vibratory tamper into up-and-down or tamping motion, or sets the vibratory plate of a vibration plate compactor into vibration. Through the tamping motion or the vibration of the respective compaction plate, the ground underneath the hand-guided ground compaction machine is increasingly tightened or compacted. Meanwhile, the hand-guided ground compaction machine can be moved across the ground in a working direction, so that a desired area of a ground can be compacted in this manner.
In particular for hand-guided ground compaction machines which include an electric on-board grid and/or a battery, it is known in the prior art to provide a sensor device for determining the ground stiffness of a ground to be compacted. This is advantageous in particular with respect to optimized efficiency in working operation. For this, the sensor device typically comprises an accelerometer. The ground stiffness increases with increasing compaction, so that an operator can infer that the ground has been compacted sufficiently from reaching a particular ground stiffness. A solution for calculating the ground stiffness during operation of a ground compaction machine is disclosed, for example, in EP 2 627 826 B1. In the prior art, the sensor device and indicating device is powered by the on-board grid or a battery of the hand-guided ground compaction machines. However, there are also hand-guided ground compaction machines, in particular vibratory tampers or vibration plate compactors, which do not include an on-board grid and have no electrical power source that could supply a sensor device. In such hand-guided ground compaction machines, which are of simple design and do not include an on-board grid, such sensor devices for determining the ground stiffness thus cannot be employed. Further, in the known systems for compaction measurement using vibration plate compactors, a sensor is either fixed to the vibrating compaction plate or the sensor is attached to the superstructure of the machine. In the case of attachment to the compaction plate, a cable is required which is particularly well protected in order to resist the rough operating conditions and heavy vibrations. On the other hand, the measuring accuracy is the highest in this case since measurements are taken directly at the work tool. If the sensor is attached to the vibration-isolated superstructure, the ground stiffness can only be measured with reduced accuracy, but the indicating device can be integrated in an advantageous manner and thus the cabling efforts can be reduced. Still, cabling cannot be fully dispensed with in this case since a power supply is needed.
The object of the invention is therefore to propose a solution for operating a sensor device for determining the ground stiffness of a ground to be compacted in particular also in hand-guided ground compaction machines of simple design, and at minimum costs.
For a hand-guided ground compaction machine as mentioned above, the object is specifically achieved by the fact that the sensor device is provided with electrical power, in particular solely, by a generator driven, in particular directly, by the at least one drive shaft. Further, it is particularly preferred here that the generator supplies electrical power solely to the sensor device. The generator may, for example, comprise a dynamo or operate according to the dynamo principle. The generator is typically designed such that it utilizes a rotational movement for generating electrical power. The required rotational movement is provided, in particular directly, by the drive device driving a drive shaft to which the generator is connected, in particular directly. The drive device sets the drive shaft into rotation, which rotation is in turn transferred to the generator, which thereby generates electrical power. A configuration in which the generator supplies electrical power solely to the sensor device and in particular forms a unit together with the sensor device has proven to be particularly advantageous. This unit composed of generator and sensor can be mounted collectively as a complete assembly group without additional cable connections being required. Such an electrical power supply to the sensor device has turned out to be particularly reliable and is moreover particularly compact, essentially maintenance-free since it is not necessary, for example, to replace batteries driving the sensor device, and, in addition, is suitable for retrofitting, as will be described in more detail below. Due to the fact that the generator is driven through operation of the drive device, a constant supply of electrical power to the sensor device is ensured at least, and in particular solely, during working operation of the ground compaction machine. The hand-guided ground compaction machine does therefore not need to be equipped with a complete on-board grid, in particular comprising a battery, i.e., the sensor device can be operated independently of an on-board grid. Due to the fact that the sensor device according to the invention and the generator are simply coupled to one of the drive shafts of the ground compaction machine, the invention can be realized in a cost-effective manner even in ground compaction machines of simple design. An “on-board grid” means in particular a unit or a system having an electrical power storage, for example an accumulator, in particular a lead accumulator. Moreover, the on-board grid may comprise an electric generator for charging the electrical power storage. With the charge in the electrical power storage, the on-board grid supplies various electric components but does in particular not supply the sensor device according to the invention.
One way to drive the generator consists in concurrently utilizing the drive shaft itself also as a shaft for the generator, for example by attaching magnets, in particular permanent magnets, directly on the drive shaft, said magnets projecting into a corresponding stator element of the sensor device so as to form a dynamo unit. Further, a connection element may be present, for example a coupling. Preferably, however, the connection element is a through-drive shaft which connects the at least one drive shaft and the generator to one another, so that the rotational movement of the drive shaft is transferred to the generator via the through-drive shaft. The through-drive shaft is a component which is axially fixed to the drive shaft, i.e. to a face side of the drive shaft, and transfers the rotational movement of the drive shaft to the generator, i.e. makes said rotational movement usable for the generator, for example a connection pin, in particular a polygonal connection pin. The through-drive shaft thus at least partially constitutes a coaxial extension of the drive shaft.
In a preferred embodiment, the sensor device, or the generator, directly adjoins, or overlaps with, the face side of the drive shaft in the axial direction of the drive shaft. However, if the superstructure of the ground compaction machine is at least partially surrounded by a housing, for example the drive device or the drive shaft, it is preferred that the generator, and in particular also the sensor device, is arranged outside a housing of the superstructure, and that the through-drive shaft extends through the housing. In other words, the drive shaft is located inside a housing of the superstructure. The generator, and in particular also the sensor device, are arranged outside the housing, thus facilitating mounting and maintenance thereof. To enable the generator to be driven and thus the sensor device to be supplied with electrical power, the through-drive shaft is preferably lead through the housing, i.e, through the housing wall, and connects the drive shaft, in particular its face side, to the generator. In this manner, the sensor device can also be seen from outside and may, for example, additionally comprise an indicating device indicating the measured values and/or the ground stiffness and/or an indication which correlates with the ground stiffness.
The at least one drive shaft may preferably be a crankshaft directly driven by the drive device. In other words, in order to supply electrical power to the sensor device, the generator is driven by the crankshaft of the drive device directly or via the through-drive shaft. A drive device may be provided which has a crankshaft that exits on only one side of the drive device. In this case, this crankshaft is utilized for driving the generator. On the other hand, it is also possible that the drive device is designed such that the crankshaft exits the drive device on two opposite sides thereof. This design is preferred in particular when the exciter unit for oscillation or vibration excitation is arranged, and driven, on the one side of the drive device, so that there is no space left on this side for the generator, or the generator and the sensor device. In this case, the generator is then driven by the other end of the crankshaft, which exits on the opposite side of the drive device. The generator is thus driven by a portion of the crankshaft which exits the drive device opposite from a further portion of the crankshaft which drives the exciter unit of the ground compaction machine. In this manner, the generator, and thus the sensor device according to the invention, can be driven by the crankshaft even in constricted space conditions as found in particular, for example, in vibratory tampers.
As an alternative to the drive effected via the crankshaft, the at least one drive shaft may be an eccentric shaft or imbalance shaft driven by an eccentric transmission or an imbalance transmission. For example, in the case of vibratory tampers, the tamping motion of the tamping foot is typically achieved through rotation of an eccentric wheel having a connecting rod eccentrically fixed to it, said connecting rod translating the rotational movement into a linear up-and-down movement of the tamping foot. The eccentric wheel sits on an eccentric shaft which is driven, via an eccentric transmission, for example a pinion meshing with the eccentric wheel, by the drive device, in particular via the crankshaft. In other words, the eccentric shaft constitutes a further rotating shaft which is present in the superstructure of the vibratory tamper in addition to the crankshaft. This eccentric shaft now can also be used to drive the generator and thus to supply electrical power to the sensor device. The vibration plate compactors are usually set into vibration or oscillation by a rotating imbalance mass. Said imbalance mass is located on an imbalance shaft which is driven by the drive device, for example the crankshaft of the drive device, via a transmission (for example a belt transmission or a hydraulic power transmission). In a vibration plate compactor, it is thus possible to use a further rotating shaft, in this case the imbalance shaft, in addition to the crankshaft of the drive device to drive the generator and thus to supply electrical power to the sensor device. The connection of the generator to the respective shaft then corresponds to the embodiments described above. Generally, the generator may be driven by any shaft of the hand-guided ground compaction machine which is fixed to the housing.
The rotational movement of the crankshaft is transferred to the eccentric shaft or the imbalance shaft via the eccentric transmission or the imbalance transmission. The eccentric shaft or the imbalance shaft may therefore include an eccentric axis or imbalance axis which is offset, in particular parallel, relative to a drive axis of the crankshaft of the drive device. The offset between the respective rotation axes is overcome by the eccentric transmission or the imbalance transmission. The eccentric axis or the imbalance axis may thus be in a different position inside the ground compaction machine depending on the design of the corresponding transmissions. A variety of different options thus exists for coupling the generator to the respective shaft, so that the respective design can be adapted to the specific space conditions of the ground compaction machine, in particular the superstructure.
In practice, it has proven to be advantageous that the sensor device comprises a transmitting device which is designed for wireless transmission of the measurement results of the sensor device to a mobile receiving device. The mobile receiving device may, for example, be a tablet computer or a smartphone, which is usually already available to the operator of the hand-guided ground compaction machine anyway. If compatible data transmission, for example WLAN, is used, such a mobile terminal may be employed as a receiving device if it is already carried by the operator of the ground compaction machine anyway. For example, through installation of a simple app, a smartphone or a tablet computer may be adapted to receive, and possibly evaluate, the data of the transmitting device of the sensor device. In this manner, no separate indicating device or evaluation device is needed at the hand-guided ground compaction machine. In particular, a power supply for the indicating device can be dispensed with since the mobile receiving device normally has its own power storage.
The invention is in particular also suitable for retrofitting existing hand-guided ground compaction machines, whether with or without an existing power source. Both the sensor device and the generator and its drive connection are optimized for incorporation into existing systems since, for example, no integration into on-board electronics or other structures is necessary. Also, the components are very compact and can be easily integrated also with respect to the required free installation space. A further preferred embodiment of the invention therefore relates to a hand-guided ground compaction machine having at least one further generator which supplies electrical power to other components of the hand-guided ground compaction machine, for example spark plugs, wherein the sensor device is supplied with electrical power solely by the first generator, and wherein the latter preferably supplies electrical power solely to the sensor device. The generator and the supply of the sensor device with electrical power are thus designed to be electrically completely separated from all other electric components of the hand-guided ground compaction machine. More particularly, the sensor device obtains its required power solely from the generator operated as explained above and is completely independent of any further power source such as a further generator or a battery or an accumulator. In this manner, the sensor device according to the invention, together with the corresponding generator, is also suitable for use as a retrofit kit for already existing hand-guided ground compaction machines regardless of whether or not they already include electronics. The sensor device according to the invention can be employed together with the generator on all hand-guided ground compaction machines regardless of this.
This can be done particularly easily if the sensor device and the generator supplying it with electrical power are jointly designed as a module or as an integral, in particular compact, assembly unit, and in particular as a retrofit kit. To this end, the sensor device and the generator particularly preferably share a common housing and/or a common fixing device for fixation to the remaining ground compaction machine. They are thus preferably designed to be mountable to a hand-guided ground compaction machine together as a discrete assembly group, so that they merely need to be connected to the drive shaft, for example via the through-drive shaft, and fixed, for example, to the housing at the superstructure. In this manner, it is possible to also equip older existing hand-guided ground compaction machines with a sensor device according to the invention, and in particular with state of the art ground stiffness determination.
In a preferred embodiment, the sensor device comprises a storage unit. The measurement data of the sensor device are continuously stored in the storage unit and can be read therefrom. The storage unit enables in particular the acquisition and monitoring of long-term trends and operating hours. The storage unit may also be provided as a unit separate from the sensor device and may receive the measurement results from the latter, for example as part of the mobile receiving device.
According to another embodiment, the sensor device is equipped with a bidirectional radio interface which enables wireless configuration of the sensor device. The sensor device is thus designed not only to send measurement results but also to receive and implement configuration commands via which various functions of the sensor device can be selected. For example, the mobile receiving device is designed to send such configuration commands upon an input by an operator.
Particularly low manufacturing costs can be achieved if the sensor device is constructed in the same way for a maximum variety of different compacting devices. Any required adaptations are performed through software parameterization via a bidirectional sending/receiving device of the sensor device. No manual intervention is thus required at the sensor device as the necessary parameters are input via the mobile terminal. The process of parameterization can be facilitated through machine-readable codes such as barcodes or QR codes, i.e., by reading these codes from the corresponding components such as the compacting device and/or the sensor device.
Additional benefits can be obtained from associating measurement data of the sensor device with information of the mobile receiving device. Here, for example, the position data of the receiving device and the period of operation of the compacting device can enable a documentation of the machine operation. For example, if the achievable productive capacity in m3/h is known, the recorded actual working time of the compaction machine can be used to ascertain whether an amount of laid material has actually been compacted.
By comparing an actual working time, which can be detected through the sensor system, and the motor operating time, unnecessary idle times can be detected and avoided in the future. Conventional operating hour meters merely acquire the motor operating time and therefore only provide an indication of necessary motor maintenance intervals. Unproductive idle times can hardly be detected in the conventional manner.
The compaction indication and additional functions may also be provided in a time and place-limited manner via Internet-based authorization. In this manner, it would be possible to integrate the sensor device as a standard device in the compacting device and to enable the indication of the compaction or further data depending on the payment of user fees. Another conceivable option would be location monitoring such that the sensor device periodically reports the place of operation of the machine via WLAN-based positioning as soon as a corresponding infrastructure is present. An anti-theft protection can thus be implemented in a simple manner.
The invention will be explained in more detail below by reference to the embodiment examples shown in the figures. In the schematic figures:
Like parts or parts acting in a like manner are designated by like reference numerals. Recurring parts are not designated separately in each figure.
In the shown embodiment of the invention according to
As also shown in
As can further be taken from
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PCT/EP2017/000867 | 7/18/2017 | WO | 00 |
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WO2018/019408 | 2/1/2018 | WO | A |
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