Abstract
A hand-guided ground compaction machine, in particular a vibratory tamper or vibration plate compactor, having a superstructure, a drive device arranged on the superstructure and having at least one drive shaft, a substructure having a compaction plate driven by the drive device, and a sensor device comprising an accelerometer for determining the ground stiffness of a ground to be compacted, wherein the sensor device is supplied with electrical power, in particular solely, by a generator driven by the at least one drive shaft.
Claims
1-11. (canceled)
12. A hand-guided ground compaction machine, in particular a vibratory tamper or a vibration plate compactor, comprising: a superstructure; a drive device arranged on the superstructure and having at least one drive shaft; a substructure having a compaction plate driven by said drive device; and a sensor device comprising at least one accelerometer for determining the ground stiffness of a ground to be compacted, wherein the sensor device is supplied with electrical power solely by a generator driven by said at least one drive shaft.
13. The hand-guided ground compaction machine according to claim 12, wherein a through-drive shaft connects the at least one drive shaft and the generator, and the generator is driven by the at least one drive shaft via said through-drive shaft.
14. The hand-guided ground compaction machine according to claim 13, wherein the generator and also the sensor device, are arranged outside a housing of the superstructure or an imbalance mass housing, and the through-drive shaft extends through said housing or said imbalance mass housing.
15. The hand-guided ground compaction machine according to claim 12, wherein the at least one drive shaft is a crankshaft driven directly by the drive device.
16. The hand-guided ground compaction machine according to claim 12, wherein the at least one drive shaft is an eccentric shaft or an imbalance shaft driven by the drive device via an eccentric transmission or an imbalance transmission.
17. The hand-guided ground compaction machine according to claim 16, wherein the eccentric shaft or the imbalance shaft includes an eccentric axis or imbalance axis which is offset and parallel, relative to a drive axis of the crankshaft of the drive device.
18. The hand-guided ground compaction machine according to claim 12, wherein 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.
19. The hand-guided ground compaction machine according to claim 12, wherein it includes a further generator which supplies power to other components of the hand-guided ground compaction machine, wherein the sensor device is supplied with electrical power solely by the first generator.
20. The hand-guided ground compaction machine according to claim 12, wherein the sensor device and the generator supplying it with power are jointly designed as a module and as a retrofit kit.
21. The hand-guided ground compaction machine according to claim 12, wherein the sensor device includes a storage unit with which long-term trends and operating hours can be acquired.
22. The hand-guided ground compaction machine according to claim 12, wherein the sensor device is equipped with a bidirectional radio interface which enables wireless configuration of the sensor device.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The invention will be explained in more detail below by reference to the embodiment examples shown in the figures. In the schematic figures:
[0021] FIG. 1 is a side view of a vibratory tamper;
[0022] FIG. 2 is a side view of a vibration plate compactor;
[0023] FIG. 3 is a cross-sectional view of the superstructure of a vibratory tamper; and
[0024] FIG. 4 is a cross-sectional view of a vibration plate compactor along line IV of FIG. 2.
DETAILED DESCRIPTION
[0025] Like parts or parts acting in a like manner are designated by like reference numerals. Recurring parts are not designated separately in each figure.
[0026] FIGS. 1 and 2 show generic hand-guided ground compaction machines 1, more specifically a vibratory tamper (FIG. 1) and a vibration plate compactor (FIG. 2). Each of the hand-guided ground compaction machines 1 includes a guide bracket 2 with which an operator can direct the ground compaction machine 1 across the ground during working operation. The guide bracket 2 of the vibration plate compactor shown in FIG. 2 can be folded to a transport position, as indicated by the dashed lines. The hand-guided ground compaction machines 1 include a superstructure 3 in which a drive device 4 is located, which is usually a combustion engine, for example a diesel or gasoline or liquefied gas type combustion engine. Moreover, the ground compaction machines 1 include a substructure 5 having a compaction plate 7, 8. In the case of the vibratory tamper, the compaction plate 7 is designed as a tamping plate which constitutes the lower end, i.e., the end facing the ground, of the tamper foot 6. The compaction plate 8 is a ground contacting plate in the form of a vibratory plate. In working operation of the hand-guided ground compaction machines 1, the compaction plates 7, 8 are set into oscillation or vibration by the drive device 4. An operator guides the ground compaction machines 1 across the ground, for example in the working direction a, thereby causing compaction of the subsoil. In the embodiment example shown, the superstructure 3 of the hand-guided ground compaction machines 1 includes a respective housing 9 which includes various components of the ground compaction machines 1.
[0027] FIG. 3 shows a cross-sectional view of the superstructure 3 of the vibratory tamper of FIG. 1. FIG. 3 in particular shows the components of the vibratory tamper inside the housing 9. The drive unit 4 sets the crankshaft 10 into rotation about the drive axis 12. More particularly, the drive device 4 drives, via the crankshaft 10, a pinion 11 which likewise rotates about the drive axis 12 and meshes with an eccentric wheel 13, which is thereby likewise set into rotation by the pinion 11. The eccentric wheel 13 rotates about the eccentric axis 14. To realize this rotational movement, the eccentric wheel 13 includes an eccentric shaft 15 which is rotatably supported at the housing 9 via eccentric bearings 16. An eccentric joint 17, via which a connecting rod 18 is fixed to the eccentric wheel 13, is located at an eccentric position on the eccentric wheel 13. In working operation of the vibratory tamper, the eccentric wheel 13 rotates, thereby setting the connecting rod 18 into a uniform up-and-down movement. The connecting rod 18 transfers this up-and-down movement to the tamper foot 6, thus driving the compaction plate 7. The pinion 11 and the eccentric wheel 13 together form the eccentric transmission 27, which drives the eccentric shaft 15. In other words, the eccentric transmission 27 transfers the rotational movement of the crankshaft 10 of the drive device 4 to the eccentric shaft 15. The eccentric shaft 15 then rotates about the eccentric axis 14, which is offset parallel to the drive axis 12 about which the crankshaft 10 rotates.
[0028] In the shown embodiment of the invention according to FIG. 3, a through-drive shaft 24 is arranged on the face side of the eccentric shaft 15 opposite the eccentric wheel 13, said through-drive shaft extending through the housing 9 and being connected to a generator 26 of a sensor device 25 which is designed to determine the ground stiffness of the ground to be compacted. The through-drive shaft 24 functionally extends the eccentric shaft 15 axially at its face side and transfers the rotational movement from the eccentric shaft 15 to the generator 26, whereby the generator 26 produces an electric current which is used to supply the sensor device 25 and in particular its accelerometer and transmitting device. The generator 26 and the sensor device 25 are arranged outside the housing 9. On the one hand, this location provides sufficient space on the vibratory tamper to accommodate the components, and, on the other hand, this enables an operator to access the sensor device 25 and the generator 26 from the outside, for example, for maintenance purposes. It also allows easy mounting of the sensor device 25 and the generator 26 from the outside. The generator 26 and the sensor device 25 are further designed as an integral module with a shared housing surrounding these two elements.
[0029] FIG. 3 also shows an alternative embodiment of the invention in which the through-drive shaft 24, the generator 26 and the sensor device 25 are driven by the crankshaft 10 of the drive motor. According to this alternative, the through-drive shaft 24 is arranged on the face side of the crankshaft 10 opposite the pinion 11, wherein said crankshaft 10 exits the drive device 4 on two opposite sides. Here, the through-drive shaft 24 is driven by that side of the crankshaft 10 which is not connected to the pinion 11. The through-drive shaft 24 is connected directly to the crankshaft 10 such that the crankshaft 10 sets the through-drive shaft 24 into rotation, so that the latter drives the generator 26. Again, this region of the second side of the crankshaft 10 exiting the drive device 4 provides sufficient space at the vibratory tamper to arrange the sensor device 25 according to the invention together with the generator 26. Due to their construction, vibratory tampers exhibit enormous accelerations even at the superstructure, said accelerations highly depending on the stiffness of the subsoil to be compacted. The attachment of the sensor unit in the described manner is therefore advantageous in various respects. The measurement of the oscillations of the tamper superstructure provides for sufficiently accurate measurement of the ground stiffness, while at the same time the power supply of the sensor device can be realized in a particularly simple manner.
[0030] FIG. 4 is a partial cross-sectional view of the vibration plate compactor according to line IV of FIG. 2. The housing 9 of the superstructure 3 of the vibration plate compactor again contains a drive device 4 which drives a crankshaft 10 about a drive axis 12. The crankshaft 10 is in turn connected to an imbalance shaft 20 via an imbalance transmission 19 and sets the imbalance shaft 20 into rotation about the imbalance axis 21. In the example shown, the imbalance transmission 19 is designed as a belt transmission, although it might also be a gear wheel transmission or the like. The imbalance shaft 20 is supported at an imbalance mass housing 28 via imbalance bearings 22 and carries an imbalance mass 23 which is located inside the imbalance mass housing 28. Rotation of the imbalance shaft 20 also sets the imbalance mass 23 into rotation about the imbalance axis 21, which sets the compaction plate 8 into oscillation or vibration. As already explained for the vibratory tamper, via the through-drive shaft 24, the sensor device 25 according to the invention and the generator 26 may generally be arranged at any shaft fixed to the housing. For example, according to one embodiment, the through-drive shaft 24 is arranged on a face side of the eccentric shaft 20. The through-drive shaft 24 extends through the imbalance mass housing 28, i.e., the housing wall of the imbalance mass housing 28, and transfers the rotation of the imbalance shaft 20 about the imbalance axis 21 to the generator 26, which is thereby driven and produces electrical power for the sensor device 25. Due to their construction, vibration plate compactors exhibit considerably dampened vibrations at the superstructure, which are only of limited use for measuring the ground stiffness. This is caused, for example, by vibration decoupling of the imbalance mass housing 28 from the housing 9, for example via rubber members. The attachment of the sensor device 25 directly to the imbalance shaft 20 is therefore advantageous in various respects. The measurement of the oscillations at the imbalance mass housing 28 of the vibration plate compactor provides for particularly accurate measurement of the ground stiffness while at the same time the power supply of the sensor device 25 can be realized in a particularly simple manner since sensitive cable connections are dispensed with. The direct attachment of the sensor device 25 to the imbalance shaft 20 also enables the cost-effective integration of further functions. For example, it is expedient to integrate a condition monitoring device for the vibration bearings 22 into the sensor device 25. The condition monitoring could, for example, be performed by directly or indirectly measuring the bearing temperature. Also, rolling bearing-typical frequencies could be extracted from the acceleration signal, so that possible damage could be detected automatically through evaluation of these signal components. A further additional function may consist in determining the actual working time with the machine. Since the sensor device 25 is supplied by a dedicated generator 26, only the actual operating hours of the machine, i.e., without any idle times, are acquired. It is thus possible, for example, to extend the maintenance intervals for the exciter unit since the actual period of operation of the machine can be acquired separately from the idle times.
[0031] As also shown in FIGS. 3 and 4, the sensor device 25 is equipped with a transmitting device which communicates the measurement results of the sensor device 25 and/or the calculated ground stiffness values to a receiving device 29, in particular a mobile receiving device 29. The mobile receiving device 29 is, for example, a tablet computer or a smartphone of an operator of the hand-guided ground compaction machines 1, which executes a program, for example an app, designed to indicate and/or evaluate the measuring signals and/or the calculated ground stiffness values. Therefore, the hand-guided ground compaction machines 1 do not require a separate indicating device, so that no further modifications of the ground compaction machines 1 are necessary and construction costs for the realization of the invention are kept low.
[0032] As can further be taken from FIGS. 3 and 4, the sensor device 25 and the generator 26 are designed as a module. The sensor device 25 and the generator 26 form an integral component, or a discrete assembly group, which can altogether be mounted on the hand-guided ground compaction machine 1, i.e., the housing 9, at the corresponding mounting position. All components are thus mounted together in only one step. To install the sensor device 25 according to the invention and the generator 26 on a hand-guided ground compaction machine 1, it is merely necessary to connect the through-drive shaft 24 to a drive shaft 10, 15, 20 and to fix the unit composed of the sensor device 25 and the generator 26 to the ground compaction machine 1, i.e., the housing 9. The invention is therefore also suitable in particular for use as a retrofit kit for any type of existing hand-guided ground compaction machine 1, regardless of whether it includes an electrical power supply, an on-board grid or any electronics at all.
