Abstract
The disclosure relates to a road finishing machine with a screed for producing a paving layer, wherein the screed includes at least one compacting unit for precompacting paving material supplied to the screed. The compacting unit includes at least one eccentric bushing mounted on an eccentric shaft supporting the same at a desired angle of rotation to thereby continuously variably set a desired tamper stroke of a tamper bar of the compacting unit. For rotating the eccentric bushing on the eccentric shaft, an adjusting mechanism mounted spaced apart from the eccentric shaft and at least partially rotatable along with a rotary motion of the eccentric shaft can be activated. Furthermore, the disclosure relates to a method for a continuously variable tamper stroke adjustment at a compacting unit of a road finishing machine.
Claims
1. A road finishing machine with a screed for producing a paving layer, wherein the screed includes a compacting unit for precompacting paving material supplied to the screed, wherein the compacting unit includes an eccentric bushing mounted on an eccentric shaft supporting the same to be rotatable to a desired angle of rotation to thereby continuously variably set a desired tamper stroke of a tamper bar of the compacting unit, wherein for rotating the eccentric bushing on the eccentric shaft, an adjusting mechanism mounted spaced apart from the eccentric shaft and at least partially rotatable along with a rotary motion of the eccentric shaft is activatable.
2. The road finishing machine according to claim 1, wherein the adjusting mechanism comprises an adjusting drive that can be activated for rotating the eccentric bushing and which is rotationally driven by means of the rotary motion of the eccentric shaft as such, and/or an adjusting transmission that can be activated for rotating the eccentric bushing and is rotationally driven by means of the rotary motion of the eccentric shaft.
3. The road finishing machine according to claim 2, wherein the adjusting drive and/or the adjusting transmission can be activated to adjust an angle of rotation of a machine element rotatably mounted on the eccentric shaft.
4. The road finishing machine according to claim 3, wherein the machine element itself forms the eccentric bushing or is connected to the eccentric bushing by means of a positive clutch.
5. The road finishing machine according to claim 3, wherein at least one further machine element is provided which is embodied for transmitting a rotary motion of the eccentric shaft to the adjusting drive and/or the adjusting transmission.
6. The road finishing machine according to claim 2, wherein during an operation of the compacting unit, the adjusting drive and/or the adjusting transmission are/is rotationally driven at a same speed or at a speed different from that of the eccentric shaft.
7. The road finishing machine according to claim 2, wherein the adjusting drive and/or the adjusting transmission are/is actuatable hydraulically, electrically and/or mechanically.
8. The road finishing machine according to claim 2, wherein the adjusting drive includes an activatable servomotor, and/or a servomotor is provided for the adjusting transmission.
9. The road finishing machine according to claim 2, wherein the adjusting mechanism comprises the adjusting transmission, and the adjusting transmission is embodied as a cam mechanism and/or includes a pair of rotatable deflection rollers.
10. The road finishing machine according to claim 9, wherein the adjusting transmission comprises the pair of rotatable deflection rollers, and the pair of rotatable deflection rollers is movably mounted transverse to the eccentric shaft for rotating the eccentric bushing on the eccentric shaft.
11. The road finishing machine according to claim 2, wherein the compacting unit comprises a plurality of the eccentric bushings rotationally mounted along the eccentric shaft, and wherein the adjusting mechanism is embodied for synchronously adjusting the plurality of the eccentric bushings, or the adjusting mechanism comprises a plurality of the adjusting drives and/or a plurality of the adjusting transmissions for separately adjusting the plurality of the eccentric bushings.
12. The road finishing machine according to claim 2, wherein the adjusting drive and/or the adjusting transmission are/is activatable for setting the desired angle of rotation of the eccentric bushing by means of a controlling system.
13. The road finishing machine according to claim 12, wherein the controlling system includes, for a dynamic adaption of the angle of rotation of the eccentric bushing, at least one control loop for responding to at least one process parameter detectable during operation of the road finishing machine.
14. The road finishing machine according to claim 2, wherein the adjusting mechanism comprises at least one sensor unit which is embodied for detecting a set angle of rotation of the eccentric bushing on the eccentric shaft supporting the same and/or for detecting a tamper stroke of the tamper bar.
15. A method for a continuously variable tamper stroke adjustment at a compacting unit of a road finishing machine, the method comprising: rotating an eccentric bushing mounted on an eccentric shaft to adjust tamper stroke, wherein for rotating the eccentric bushing on the eccentric shaft, an adjusting mechanism mounted at a distance to the eccentric shaft and at least partially rotating along with a rotary motion of the eccentric shaft is activated.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] Advantageous embodiments of the disclosure will be illustrated more in detail with reference to the following figures.
[0048] FIG. 1 shows a schematic side view of a road finishing machine;
[0049] FIG. 2 shows a compacting unit for a screed of a road finishing machine according to a first embodiment;
[0050] FIG. 2A shows a first operating state of the compacting unit shown in FIG. 2;
[0051] FIG. 2B shows a second operating state of the compacting unit shown in FIG. 2;
[0052] FIG. 2C shows a variant of the first embodiment shown in FIG. 2 for an overall stroke adjustment;
[0053] FIG. 2D shows a variant of the embodiment shown in FIG. 2 for an individual stroke adjustment;
[0054] FIG. 3 shows a compacting unit for a screed of a road finishing machine according to a second embodiment;
[0055] FIG. 3A shows a sectional representation of the adjusting mechanism of the second embodiment shown in FIG. 3;
[0056] FIG. 3B shows a separate representation of the adjusting mechanism of the embodiment shown in FIG. 3;
[0057] FIG. 3C shows a variant of the second embodiment shown in FIG. 3 for an overall stroke adjustment; and
[0058] FIG. 3D shows a schematic representation of the second embodiment of FIG. 3 for an individual stroke adjustment.
[0059] Equal components are always provided with equal reference numerals in the figures.
DETAILED DESCRIPTION
[0060] FIG. 1 shows a road finishing machine 1 with a screed 2 for producing a paving layer 3 in the paving travel direction R. The screed 2 has at least one compacting unit 4 for precompacting a paving material 5 supplied to the screed 2. The compacting unit 4 includes a tamper bar 6 which can be driven with a variable tamper stroke H and/or a variable frequency F for precompacting the paving material 5 supplied to the screed 2.
[0061] FIG. 2 shows the compacting unit 4 separately in an enlarged perspective representation. The compacting unit 4 has a bearing support 7 fixed to the screed body and an eccentric shaft 8 rotationally mounted thereto. The eccentric shaft 8 drives a connecting rod 9 to which the tamper bar 6 is fixed.
[0062] FIG. 2 furthermore shows an adjusting mechanism 10 which is rotationally driven by means of the eccentric shaft 8. The adjusting mechanism 10 can be activated to set a variable desired tamper stroke 11 for the tamper bar 6. To this end, the adjusting mechanism 10 rotating along comprises an adjusting drive 12 and/or an adjusting transmission 13. According to FIG. 2, the adjusting drive 12 and the adjusting transmission 13 are embodied as a function unit. This function unit is coupled to a rotary motion of the eccentric shaft 8 by means of a synchronous belt 14.
[0063] The adjusting mechanism 10 can, without being additionally activated, return the torque, which drives by means of the synchronous belt 14 at its input end and causes it to rotate, to a machine element 16 rotationally mounted on the eccentric shaft 8 by means of a further synchronous belt 15 provided at its output end. By an additional activation of the adjusting mechanism 10, a phase angle of the machine element 16 mounted on the eccentric shaft 8 can be changed. By means of this phase adjustment, an eccentric bushing 17 (see FIG. 2C) rotationally mounted within the connecting rod 9 on the eccentric shaft 8 and coupled to the machine element 16 can be adjusted. According to FIG. 2, for rotating the eccentric bushing 17 on the eccentric shaft 8, the adjusting mechanism 10 mounted spaced apart from the eccentric shaft 8 and rotating along with the rotary motion of the eccentric shaft 8 can be activated.
[0064] With reference to FIGS. 2A and 2B, the performance of a phase adjustment by means of the adjusting mechanism 10 to adjust the tamper stroke 11 is schematically shown.
[0065] In FIG. 2A, the synchronous belt 14, which is guided on a pulley 18 mounted on the eccentric shaft 8 in a torque-proof manner, transmits the rotary motion of the eccentric shaft 8 to a housing 19 of the adjusting mechanism 10. The housing 19 can be embodied with a diameter as that of the pulley 18. Thereby, between the eccentric shaft 8 and the adjusting mechanism 10, a belt drive is created which takes care that the adjusting mechanism 10 rotates at the speed of the eccentric shaft 8.
[0066] In FIG. 2A, the adjusting mechanism 10 rotating along is not additionally activated, so that a torque applied to its housing 19 at its input end is forwarded to the machine element 16 via the further synchronous belt 15 fixed to its output end. According to FIG. 2A, the consequence of this is that the eccentric bushing 17 mounted within the connecting rod 9 rotates at the speed of the eccentric shaft 8, that means it maintains its angular position with respect to the eccentric shaft 8. FIG. 2A shows this situation schematically by means of the two markings A, B running equally.
[0067] In FIG. 2B, the adjusting mechanism 10 has performed a phase adjustment 26 with respect to FIG. 2A. This is shown by means of the two markings A, B now represented shifted with respect to each other. In response thereto, the machine element 16 has rotated with respect to the position shown in FIG. 2A on the eccentric shaft 8 corresponding to the phase adjustment 26. This causes the eccentric bushing 17 coupled to the machine element 16 to also assume an angular position on the eccentric shaft 8 changed by the phase adjustment 26, so that this results, together with the eccentricity of the eccentric shaft 8, in a new desired tamper stroke 11.
[0068] FIG. 2C shows a first variant of the embodiment shown in FIG. 2 for an overall stroke adjustment at the compacting unit 4. This means that a plurality of eccentric bushings 17 positioned along the eccentric shaft 8 are synchronously rotatable by means of the adjusting mechanism 10.
[0069] In FIG. 2C, the eccentric shaft 8 is driven by a motor 20. The belt drives represented in FIG. 2 for coupling the eccentric shaft 8 with the adjusting mechanism 10 and for coupling the adjusting mechanism 10 with the machine element 16 are replaced by drive wheels 21, 22 and adjusting wheels 23, 24 in FIGS. 2C and 2D. The drive wheel 21 is mounted on the eccentric shaft 8 in a torque-proof manner. The drive wheel 22 is seated on the housing 19 of the adjusting mechanism 10 in a torque-proof manner. The adjusting mechanism 10 is mounted on a shaft 25 in a torque-proof manner. The adjusting mechanism 10 is configured to perform the phase adjustment 26 between the drive wheel 22 mounted on its housing 19 and the adjusting wheel 23 mounted at its output end. The phase adjustment 26 performed by means of the adjusting mechanism 10 is transmitted from the adjusting wheel 23 to the adjusting wheel 24 and the machine element 16. According to FIG. 2C, the adjusting wheel 24 and the machine element 16 are integrally formed. By means of a rotation of the machine element 16, the eccentric bushing connected thereto by means of a claw clutch 27 in FIG. 2C is rotated on the eccentric shaft 18. Thereby, a change of the (desired) tamper stroke 11 of the tamper bar 6 occurs.
[0070] In FIG. 2C, the adjusting mechanism 10 has a sensor unit 28 which is configured to detect the phase adjustment 26 and thus also the angular position of the eccentric bushing 17 on the eccentric shaft 8. The sensor unit 28 transmits its measuring results continuously to a controlling system 29 connected thereto. The controlling system 29 can store the desired tamper stroke 11, the controlling system 29 being configured to calculate an actual tamper stroke from the measured phase adjustment 26 and compare it with the stored desired tamper stroke 11, based on which the controlling system 29 emits a control signal 30 to the adjusting drive 12 of the adjusting mechanism 10. The adjusting drive 12, for example a synchronous motor M rotating along, can then adapt the phase adjustment 26 based on the control signal 20.
[0071] The controlling system 29 can include a control loop RK which responds to a process parameter P measured during the operation of the road finishing machine 1, based on which a dynamic adaption of the angle of rotation, that means a dynamic phase adjustment 26, for varying the tamper stroke 11 is possible. The functional principle of the controlling system 29 and/or of the control loop RK is also applicable in connection with all following embodiments.
[0072] FIG. 2C furthermore shows that the adjusting mechanism 10 has an adjusting shaft 31 at its output end. According to FIG. 2C, the adjusting wheel 23 is mounted on the adjusting shaft 31 in a torque-proof manner. By this it is possible to transmit the phase adjustment 26 set by means of the adjusting mechanism 10 in FIG. 2C via the adjusting shaft 31 synchronously to another unit section 32. By means of further adjusting wheels 33, 34, an eccentric bushing not shown at the unit section 32 is rotated there analogously synchronously to the eccentric bushing 17.
[0073] FIG. 2C thus shows that the adjusting mechanism 10 is embodied, via the adjusting shaft 31, for synchronously adjusting a plurality of eccentric bushings 17 rotationally mounted along the eccentric shaft 8.
[0074] FIG. 2D shows a device that is embodied for separately adjusting a plurality of eccentric bushings 17 rotationally mounted along the eccentric shaft 8. By means of this device, an individual stroke adjustment is thus possible.
[0075] According to FIG. 2D, the compacting unit 4 comprises the adjusting mechanism 10 for varying the desired tamper stroke 11 of the tamper bar 6, and furthermore an additional adjusting mechanism 10′ for the further unit section 32. The adjusting mechanism 10′ is driven via the shaft 25 and has a sensor unit 28′ by means of which a phase adjustment 26′ set at the unit section 32 can be measured on the basis of which the eccentric bushing 17′ mounted at the unit section 32 is rotated on the eccentric shaft 8. For an independent actuation of the two adjusting wheels 23, 33, these are rotationally mounted on the shaft 25. It is thus possible to adjust, at the respective unit sections of the compacting unit 4, the desired tamper stroke 11, 11′ for the respective tamper bars 6, 6′ independently with respect to each other.
[0076] FIG. 3 shows a second embodiment of the compacting unit 4. The compacting unit 4 furthermore has an adjusting mechanism 35. The adjusting mechanism 35 can be activated to rotate the machine element 16 rotationally mounted on the eccentric shaft 8 such that the desired tamper stroke 11 can be adjusted at the tamper bar 6.
[0077] The adjusting mechanism 35 of FIG. 3 has a pair of deflection rollers 36a, 36b rotating along. The two deflection rollers 36a, 36b are mounted to be reciprocated transversely to the eccentric shaft 8 which is shown by the double arrows v1, v2. The adjusting mechanism 35 is connected to the rotary motion of the eccentric shaft 8 by means of drive disks 37, 38, 39 mounted in a torque-proof manner by means of synchronous belts 40, 41 guided thereon. The drive disks 38, 39 separately represented in FIG. 3 could also be embodied as one component. A displacement of the two deflection rollers 36a, 36b transverse to the eccentric shaft 8 causes the machine element 16 connected to the adjusting mechanism 35 via the synchronous belt 41 to rotate on the eccentric shaft 8. The eccentric bushing 17 fixed thereto thereby also changes its angular position on the eccentric shaft 8, so that the (desired) tamper stroke 11 is adjusted.
[0078] The functional principle of the phase adjustment by means of the adjusting mechanism 35 is represented in greater detail in FIG. 3A. In the left half of the picture of FIG. 3A, the drive disk 39 and the machine element 16 are both mounted at an angle of rotation φ. For this, the adjusting mechanism 35 assumes a corresponding position according to FIG. 3A. This positioning of the two deflection rollers 36a, 36b rotating along results in a minimal tamper stroke 11 for the tamper bar 6.
[0079] In the right half of the picture of FIG. 3A, the setting of the adjusting mechanism 35 is shown for a maximal tamper stroke 11 of the tamper bar 6. In response to a displacement {right arrow over (R1, R1′)}, {right arrow over (R2, R2′)} of the two deflection rollers 36a, 36b, a new angle of rotation φ resulted for the machine element 16. The displacement of the two deflection rollers 36a, 36b rotating along transversely to the eccentric shaft 8 driving the same thereby causes the phase adjustment 26 of the machine element 16, whereby the eccentric bushing 17 rotates on the eccentric shaft 8.
[0080] FIG. 3B shows a potential construction for the adjusting mechanism 35. The adjusting mechanism 35 includes an adjustably mounted cam disk 42 with a first cam path 43 for the deflection roller 36a and with a second cam path 44 for the deflection roller 36b. Furthermore, the adjusting mechanism 35 has a stationarily mounted cam disk 45 with a guide path 46 for the deflection rollers 36a, 36b. By means of a displacement of the cam disk 42 in the direction E, the two deflection rollers 36a, 36b are shifted together in the direction E in the guide path 46. By the displacement of the two deflection rollers 36a, 36b, the phase adjustment 26 takes place at the machine element 16 whereby the eccentric bushing 17 rotates on the eccentric shaft 8.
[0081] Furthermore, FIG. 3B shows a section A-A in its right picture half. The deflection roller 36a is mounted on a bolt 47. To reduce a frictional resistance, the deflection roller 36a is fixed to the bolt 47 by means of a rolling bearing 48.
[0082] FIGS. 3C and 3D show variants of the adjusting mechanism 35, the variant shown in FIG. 3C being configured to synchronously adjust a plurality of eccentric bushings 17 mounted along the eccentric shaft 8 (overall stroke adjustment), and the variant represented in FIG. 3D being configured for an individual stroke adjustment at respectively adjacent unit sections of the compacting unit 4.
[0083] In FIG. 3C, the adjusting mechanism 35 is mounted between the drive wheel 37 and an adjusting wheel 50. A phase adjustment 26 set by means of the adjusting mechanism 35 in FIG. 3C acts on the adjusting wheel 50 via the synchronous belt 40, wherein the adjusting shaft 31′ supporting the adjusting wheel 50 can transmit the torque to further unit sections of the compacting unit 4 synchronously to set eccentric bushings mounted there corresponding to the eccentric bushing 17 of FIG. 3C.
[0084] In FIG. 3C, the phase adjustment 26 set by means of the adjusting mechanism 35 is transmitted to the machine element 16 via the two adjusting wheels 50, 51 and the synchronous belt 41, which machine element assumes a corresponding angle of rotation φ on the eccentric shaft 8. The machine element 16 is connected to the eccentric bushing 17 via the claw clutch 27. The phase adjustment 26 set at the machine element 16 is thereby transmitted to the eccentric bushing 17, based on which the desired tamper stroke 11 can be set.
[0085] The schematic representation of FIG. 3D shows that the adjusting mechanism 35 is arranged according to FIG. 3, that means it can generate the phase adjustment 26 between the drive wheel 39 and the machine element 16. According to FIG. 3D, for each unit section of the compacting unit 4, a separate adjusting mechanism 35 can be arranged, so that the respective tamper strokes 11 of the unit sections can be activated independently.
