Method for laying down a pavement, a screed and a road paver

Abstract

Method for laying down a pavement consisting of paving material with a road paver screed in which a compaction unit pre-compacts the paving material at cyclical work cycles with a selectable stroke and at a selectable frequency while the pavement is laid down at a selectable paving speed and at least the stroke is automatically adjustable in response to paving parameters.

Claims

1. A screed for road pavers, comprising a compaction unit with a tamper bar driven by an eccentric drive in cyclical work cycles with a selectable stroke and at a selectable frequency relative to a sole plate of the screed for pre-compacting a pavement made from paving material, wherein the eccentric drive in the compaction unit comprises an adjusting drive for the remote-controlled automatic adjustment of the stroke of the tamper bar, wherein the adjusting drive cooperating with a rotatingly drivable eccentric shaft and an eccentric bushing arranged on the eccentric shaft in a rotationally fixed manner being displaceable in a direction transverse to the axis of the eccentric shaft, the eccentric bushing being rotatable in a connecting rod driving the tamper bar, such that the stroke of the tamper bar is adjustable by a transverse displacement of the eccentric bushing relative to the eccentric shaft, the eccentric shaft and the transversely adjustable eccentric bushing coupled by guide blocks with the eccentric shaft in a rotationally fixed manner have provided therein the guide blocks adjustable in a direction transverse to the eccentric shaft by means of at least one control rod of the adjusting drive, the control rod being guided in the eccentric shaft in an axially shiftable manner, each of the guide blocks having an inclined guide surface, and wherein each inclined guide surface of a respective guide block radially abuts in an axially moveable manner on an inclined ramp in the eccentric bushing or on the control rod.

2. Screed according to claim 1, wherein the adjusting mechanism is operable hydraulically, electrically or mechanically, either continuously or stepwise during the pavement laying operation.

3. Screed according to claim 1, comprising an automatic control system connected to sensors for detecting actual paving parameters and being operatively connected to the adjusting mechanism, and into which control system paving parameters for at least one of the paving screed, the pavement thickness and a target pre-compacting degree producible by the compaction unit can be entered or stored.

4. Screed according to claim 3, wherein the control system comprises at least one characteristic curve representing paving parameters for automatically adjusting the stroke in response to paving parameters.

5. Screed according to claim 3, wherein the control system comprises a characteristic map representing paving parameters for automatically adjusting the stroke in response to paving parameters.

6. A screed for road pavers, comprising a compaction unit with a tamper bar driven by an eccentric drive in cyclical work cycles with a selectable stroke and at a selectable frequency relative to a sole plate of the screed for pre-compacting a pavement made from paving material, wherein the eccentric drive in the compaction unit comprises an adjusting drive for the remote-controlled automatic adjustment of the stroke of the tamper bar, wherein the adjusting drive cooperating with a rotatingly drivable eccentric shaft and an eccentric bushing arranged on the eccentric shaft in a rotationally fixed manner being displaceable in a direction transverse to the axis of the eccentric shaft, the eccentric bushing being rotatable in a connecting rod driving the tamper bar, such that the stroke of the tamper bar is adjustable by a transverse displacement of the eccentric bushing relative to the eccentric shaft, wherein the eccentric shaft and the transversely adjustable eccentric bushing coupled by guide blocks with the eccentric shaft in a rotationally fixed manner have provided therein the guide blocks adjustable in a direction transverse to the eccentric shaft by means of at least one control rod of the adjusting drive, the control rod being guided in the eccentric shaft in an axially shiftable manner, each of the guide blocks having an inclined guide surface, and wherein each inclined guide surface of a respective guide block radially abuts on an inclined guide ramp of the at least one axially shiftable control rod.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the subject matter of the invention are explained with reference to the drawings, in which:

(2) FIG. 1 is a schematic side view of a road paver equipped with a screed while laying down a pavement;

(3) FIG. 2 is a diagram for illustrating two characteristic curves or a characteristic map;

(4) FIG. 3 is a perspective view showing a part of a screed equipped with a compaction unit;

(5) FIG. 4 is a perspective sectional illustration showing an embodiment of a stroke adjusting device;

(6) FIG. 5 is a perspective partial sectional view showing a further embodiment of a stroke adjusting device;

(7) FIG. 6 is a longitudinal section through a further embodiment of a stroke adjusting device;

(8) FIG. 7 is a longitudinal section through a further embodiment of a stroke adjusting device;

(9) FIG. 8 is a perspective sectional view showing a further embodiment of a stroke adjusting device;

(10) FIG. 9 is a perspective sectional illustration showing a further embodiment of a stroke adjusting device; and

(11) FIG. 10 is a perspective view of a further embodiment of a stroke adjusting device.

DETAILED DESCRIPTION OF THE INVENTION

(12) A road paver 1 in FIG. 1 for laying down a pavement 6 of a bituminous or concrete-type paving material 5 on a subgrade 7 is equipped on a chassis 2 with a paving material hopper 4 and in a driver's cab with a control panel P of a controller, e.g. with a control system 25. As an alternative, the control system 25 could also be arranged at a different place inside the road paver 1 or in a screed 3 towed by the road paver, namely in functional association with the controller or the control panel P or an external control panel P′ arranged on the screed 3.

(13) The screed 3 is fastened to traction bars 8 that at both sides are connected to articulation points 9 of the road paver 1. The articulation points 9 can be moved upwards and downwards via adjusting devices 10, such as leveling cylinders, for instance in order to adjust the pavement thickness S of the laid-down pavement 6. The screed 3 comprises, for instance, a base screed 11 and extension screeds 12 movable on said base screed, each with a compaction unit 13 comprising at least a tamper 14 and a tamper bar, respectively, and a sole plate 18 acting on the paving material 4, wherein preferably the screed 3 floatingly operates at a small positive setting angle α relative to a plane in parallel with the subgrade 7. The tamper bar 14 is cyclically drivable at work cycles for precompaction and carries out strokes H at a frequency F. During the ongoing paving work the road paver 1 is running at a paving speed V on the subgrade 7.

(14) If necessary, the screed 3 (in the base screed 11 and each extension screed 12) additionally includes at least one eccentric vibrator (not shown) for acting on the sole plate 18 with vertical pulses, and optionally in work travel direction at the rear side at least one pressing bar of a high-performance compaction device (not shown). The eccentric vibrator and the high-performance compaction device are selective options of a screed 3 whereas the tamper 14 can pertain to the basic equipment.

(15) The paving speed V and also the pavement thickness S are paving parameters that are changing or can be changed optionally even during the ongoing paving work. The tamper 14 must produce a precompaction in the paving material 5 that has loosely been poured onto the subgrade 7, and the precompaction should be kept at least predominantly constant independently of varying paving parameters. Further paving parameters that might be of relevance to precompaction may be type and consistency of the paving material 5, the temperature thereof, ambient conditions, the design of the screed 3, or the like.

(16) According to the invention the precompaction is kept substantially constant, independently of the paving parameters varying during the ongoing paving work, in that at least the stroke H of the work cycles of the tamper 14 is adjusted in response to at least one paving parameter, optionally even automatically, expediently also the frequency F, namely via the control system 25 that receives or is aware of at least one paving parameter as a control variable, and on which preferably a desired precompaction degree is set as a setpoint or target value. The control system 25 can be operated with characteristic curves and/or a characteristic map. Each characteristic curve or the characteristic map is predetermined and stored. Expediently, the control system 25 is an automatic one and is computerized.

(17) FIG. 2 shows a diagram of the stroke H (or of the frequency F) over the pavement thickness S (or the paving speed V). The continuous characteristic curve H illustrates how the stroke H is here continuously increasing with an increasing pavement thickness S (or with an increasing paving speed V). The broken lines outline the measure known from the prior art, i.e. to change the stroke H in several steps, each with an interrupted paving operation, wherein the obliquely hatched fields X and Y illustrate that the stroke H changed according to the staircase profile, or the precompaction, is not matching over a considerable portion of the changes made in the pavement thickness S or the paving speed V.

(18) The continuous characteristic curve F illustrates the also possible change in the frequency with an increasing pavement thickness S or paving speed V. The characteristic curves H, F can be stored in a characteristic map executed by the control system 25 during the ongoing paving work. The characteristic curve F, H or the characteristic map is predetermined such that with respect to a high and constant final quality of the laid-down pavement 6 there is always an optimum ratio between the pavement thickness and/or the paving speed and at least the stroke H; expediently, the frequency F is also optimal. The stroke H and optionally also the frequency F are expediently adjusted either automatically and even during the ongoing paving work while changes in at least one paving parameter such as the pavement thickness S and/or the paving speed V are sensed, or in an operator-controlled manner.

(19) FIG. 3 illustrates an inner portion of the screed 3 with the tamper 14. The tamper bar 14 is shielded on the front side of the screed 3 by a cover 19 (draw-in snout) and is substantially vertically movably guided between the cover 19 and the front edge of the sole plate 18. On a frame 17 of the screed 3 that carries the sole plate 18 on the bottom, a bearing block 16 is mounted having a relative height position that can e.g. be adjusted by means of an adjusting screw 20 in such a manner that the tamper bar 14 in the lower dead center of each work cycle occupies a specific relative position with respect to the sole plate 18. In the bearing block 16 (a plurality of bearing blocks 16 may be mounted over the length of the frame 17) an eccentric shaft 15 is rotatably supported and includes a respective eccentric section 22 with a specific eccentricity. The eccentric section 22 is located in a connecting rod 21 which connects the eccentric shaft 15 to the tamper bar 14. On the eccentric section 22 of the eccentric shaft 15, an eccentric bushing 23 is coupled in a rotationally fixed manner with the eccentric section 22, for instance in the illustrated embodiment via an adjusting mechanism 24 supported on the frame 17, and is rotatably supported in the connecting rod 21. With the help of the adjusting mechanism 24 the eccentric bushing 23 can be rotated relative to the eccentric section 22 of the eccentric shaft 15 and can be coupled again in a rotationally fixed manner with the eccentric shaft 15 in the respectively adjusted rotary position. The relative rotation of the eccentric bushing 23 relative to the eccentric section 22 effects an adjustment of the stroke which is transmitted by the connecting rod 21 to the tamper bar 14. The stroke can be adjusted preferably automatically via the control system 25 which is in operative communication with the adjusting mechanism 24, namely depending on changes in specific paving parameters. Alternatively, the adjusting mechanism 24 could also be controlled or actuated by an operator, if necessary.

(20) The illustration of the adjusting mechanism 24 in FIG. 3 is schematic because the adjusting mechanism 24 must of course act due to the rotational direction of the eccentric shaft 15 indirectly as a stroke adjusting device via the eccentric shaft 15 on the eccentric bushing 23. This shall be explained in detail with reference to the further embodiment.

(21) In the adjusting mechanism 24 shown in FIG. 4, the eccentric bushing 23 is rotatably seated on the eccentric section 22 of the eccentric shaft 15. The shaft is e.g. hollow in such a way that an interior control rod 27 leads to an adjusting drive 26 located outside of the eccentric shaft 15. The control rod 27 is coupled with a driver 28 which is adjustable in a groove 29 axially in the eccentric shaft 15 and is connected to said shaft in a rotationally fixed manner and which with an extension 30 projecting out of the groove 29 to the outside engages into a thread-like guide path 31 of the eccentric bushing 23.

(22) The eccentric section 22 exhibits a first eccentricity relative to the rotational axis of the eccentric shaft 15, but is cylindrical on the outer circumference. The cylindrical outer circumference of the eccentric bushing 23 is eccentric relative to the cylindrical inner circumference. Since the cylindrical outer circumference of the eccentric bushing 23 is rotatable in the connecting rod 21, and since the tamper bar 14 is movable in a fixed vertical plane, the extent of the eccentricity resulting from the first and second eccentricities depends on which relative rotational position is set between the eccentric bushing 23 and the eccentric section 22. The efficient eccentricity extent determines half the stroke H of a work cycle. Hence, when the driver 28 is moved towards the axis of the eccentric shaft 15, the stroke H can be adjusted in a continuously variable manner between a minimum and a maximum. The eccentric bushing 23 always remains coupled with the eccentric shaft 15 in a rotationally fixed manner. The adjusted axial position of the driver 28 is e.g. maintained by the adjusting drive 26.

(23) The eccentric shaft 15 is rotatably supported e.g. at the left end in FIG. 4 in a bearing block (which is here not shown) and is driven from the end at the right side in FIG. 4 via a hydromotor (not shown). The adjusting drive 26 can thus be arranged in front of the end at the left side in FIG. 4 in the screed or on the frame 17.

(24) FIG. 5 mainly differs from FIG. 4 in that the adjusting mechanism 24 contains the driver 28 which is axially displaceable in the outwardly open groove 29 of the eccentric shaft 15, in such a matter that the adjusting drive 26 is operative via the control rod 27 from the outside of the eccentric shaft 15. The extension 30 of the driver 28 engages into the thread-like guide path 31 of the eccentric bushing 22 which, though it is seated in a relatively rotatable manner on the eccentric section 22 of the eccentric shaft 15, remains coupled with the eccentric shaft 15 in a rotationally fixed manner via the driver 28, the groove 29 and the extension 30 in each axial position of the driver 28.

(25) The adjusting mechanism 24 shown in FIG. 6 comprises a rotary type step switching mechanism which is cyclically operated by the adjusting drive 26, which is e.g. supported on the frame 17 of the screed, so as to rotate the eccentric bushing 23 relative to the eccentric section 22 of the eccentric shaft 15. In the connecting rod 21 the eccentric bushing 23 is rotatably supported via at least one roller bearing 32. In the eccentric section 22, at least one axial groove 29 is provided having arranged therein an adjusting mechanism 33 which is coupled with the eccentric shaft 15 to be axially movable, but rotationally fixed. At the left end of the adjusting mechanism 33 in FIG. 6 a sawtooth gearing 34 (circumferential gearing) is provided, as well as a sawtooth gearing 35 that is circumferentially offset relative thereto and provided at the right end of the adjusting mechanism 33. The eccentric bushing 23 has corresponding sawtooth gearings 37 and 36, respectively, at both ends. The axial length of the eccentric bushing 23 between the sawtooth gearings 36, 37 thereof is slightly shorter than the inner width between the sawtooth gearings 35, 34. The adjusting mechanism 33 is hydraulically axially adjustable through this width difference for instance by means of a ring piston 41 of the adjusting drive 26 (hydraulically actuatable ring chamber 40). The left-side end of the adjusting mechanism 33 is supported on a spring 39 of a stop 38 on the eccentric shaft 15.

(26) For rotating the eccentric bushing 23 on the eccentric section 22 the adjusting mechanism 33 is moved by the ring piston 41 out of the position shown in FIG. 6 to the left side until the gearings 34, 37 are disengaged and the gearings 35, 36 are meshing with each other. The eccentric bushing 23 is thereby rotated by a pitch by way of a circumferential displacement between at least the gearings 34 and 35. The pressure is thereafter reduced in the ring chamber 40 so that the spring 39 shifts the adjusting mechanism 33 back into the position shown in FIG. 6, and e.g. the eccentric bushing 23 is further rotated by a further pitch and is thereafter again coupled in a rotationally fixed manner with the eccentric section 22.

(27) In FIG. 7, the adjusting mechanism 24 comprises the ring piston 41 as the adjusting drive 26. The adjusting drive 26 can be supported on the frame 17 of the screed. The ring piston 41 directly acts on an axial end of the eccentric bushing 23, which bushing 23 is pressed by the spring 39, which is supported on the stop 39 on the eccentric shaft 15, via a stop ring 42 and a roller bearing 43 axially onto a conical section 22′ of the eccentric section 22 of the eccentric shaft 15 and coupled with the eccentric shaft 15 in a rotationally fixed manner. The eccentric bushing 23 can be moved to the left side against the force of the spring 39 by the ring piston 41 out of the position shown in FIG. 7, so that the friction connection with the conical section 22′ is disconnected or loosened, and for instance the eccentric shaft 15 can be rotated in the roller bearing 43 relative to the eccentric bushing 23 until the ring piston 41 is retracted again and the eccentric bushing 23 is brought by the spring 39 into renewed frictional contact with the conical section 22′. Alternatively, for instance in a way similar to the one in FIG. 6, the relative rotational movement could also be carried out on the eccentric bushing 23. The connecting rod 21 follows these minor axial movements of the eccentric bushing 23 in the embodiment in FIG. 7. Alternatively, the roller bearing 32 could have an axial play in the connecting rod 21 or on the eccentric bushing 23. In an alternative (not shown), the eccentric bushing 23 could even be coupled through a gearing with the conical section 22′ in a rotationally fixed manner.

(28) In the embodiment shown in FIG. 8 and regarding the stroke adjusting device with the adjusting mechanism 24, and in contrast to the previously described embodiments of FIGS. 4 to 7, the eccentric bushing 23 is not rotated relative to the eccentric section 22 of the eccentric shaft 15, but it is shifted in a direction transverse to the axis of the eccentric shaft 15 so as to change the whole efficient eccentricity and thus the stroke.

(29) The eccentric bushing 23 can e.g. be configured with coaxial inner and outer cylindrical circumferences, i.e. in a circular cylindrical manner, and arranged in a rotationally fixed manner on two opposite guide blocks 44 that are shiftable in outwardly open grooves of the pierced eccentric shaft 15 in a direction transverse to the axis of the eccentric shaft 15 and are rotationally fixed with the eccentric shaft. Each guide block 44 is provided on the inside with an inclined guide surface 45 that is standing on an inclined guide ramp 47 of a control rod 46 which is axially displaceable in the eccentric shaft 15 by means of the adjusting drive 26 and fixable in the respectively selected adjusting position. The adjusting drive 36 can be configured hydraulically, electrically or mechanically. Although the eccentric bushing 23 is cylindrical (which is advantageous under technical manufacturing aspects), it exhibits an eccentric action relative to the eccentric section 22.

(30) In the embodiment of FIG. 9, which is functionally similar to the embodiment of FIG. 8, two diametrically opposite axial grooves 29 are formed in the eccentric section 22 of the eccentric shaft 44, the guide blocks 44 being coupled in said grooves with the eccentric shaft 15 in an axially movable and rotationally fixed manner. Each guide block 44 is engaged by a control rod 46′ which is or can be coupled with the adjusting drive 26. The inclined guide surface 47′ is formed on the outside on the guide block 44 and engages into an axial groove on the inner surface of the eccentric bushing 23. The inclined guide ramp 45′ is formed in said axial groove, so that the eccentric bushing is shifted, similar to the way shown in FIG. 8, in a direction transverse to the axis of the eccentric shaft by the axial displacement of the guide blocks 44 and remains coupled in a rotationally fixed manner with the eccentric shaft 15. In this instance, too, the eccentric bushing 23 can be cylindrical.

(31) In FIG. 10, the adjusting mechanism 24 is integrated into a toggle mechanism via which the rotational movement of the eccentric shaft 15 with its eccentric section 22 is transmitted via a push rod 48 rotatably supported on the eccentric section 22 and via an articulation axis 49 to the connecting rod 21 on which the tamper bar 14 is secured. An end of an adjusting lever 50 is articulated to the connecting rod 21, preferably on the same articulation axis 49, the adjusting lever being supported with a pivot abutment 51 (e.g. a pin) in a guide path 52 of the bearing block 16′ of the eccentric shaft 15. The bearing block 16′ can be mounted on the frame 17 of the screed. The guide path 52 is e.g. a straight or arcuate elongated slit in the bearing block 16′ and extends in a plane which transversely cuts the eccentric shaft 15. The adjusting drive 26 is operative between the bearing block 16′ and the pivot abutment 51 so as to adjust the pivot abutment 51 inside the guide path 52. This changes the eccentricity sensed on the eccentric section 22 and transmitted by the adjusting lever 50 to the connecting rod 21, or the stroke of the tamper bar 14, respectively.

(32) Expediently, the guide path 52 is configured and arranged relative to the axis of the eccentric shaft 15 and the articulation axis 49 such that independently of the adjusting position of the pivot abutment 51 in the guide path 52 the lower dead center of the work cycles of the tamper bar 14 remains stationary in relation to the sole plate 18, i.e. in the stroke adjustment only the upper dead center shifts.

(33) The rotation of the eccentric shaft 15 reciprocates the push rod 48 substantially in parallel with the upper side of the frame 17 via the eccentric shaft 22. Said swing movement effects a pivotal movement of the adjusting lever 50 about the pivot abutment 51 via the joint articulation axis 49, said pivot movement describing a circular-arc section. The adjusting lever 50 derives therefrom a substantially vertical stroke component for the connecting rod 21. The extent of this stroke component is changed by adjusting the pivot abutment 51 in the guide path 52.

(34) The articulation points 9 of the traction bars 8 of the road paver 1 of FIG. 1 are adjustable in their height with the leveling cylinders 10 e.g. via actuators 10′ (hydraulic valves or the like) and influence the setting angle α of the screed 3. The setting angle α should be positive, but have an optimal size, i.e. not too flat and not too steep, and its optimal size is maintained by the control system 25. Lifting cylinders 28 are additionally hinged to the chassis 2, the lifting cylinders acting on the traction bars 8 and serving to position the screed 3 in a lifted position for instance for transportation travel, or to carry out a screed relief or optionally to intensify the support pressure of the screed 3. The tamper 14 of the compaction unit 13 is (see FIG. 3) for instance operable by means of an eccentric drive with selectable stroke H and selectable frequency F.

(35) In the control panel P or external control panel P′ a speed selector 26 is provided for setting the paving speed V. The speed selector 26 can be adjusted via an actuator (not shown) and optionally by the control system 25 so as to vary the paving speed V. The paving speed V is sensed by a symbolically illustrated sensor 41 and transmitted to the control system 25. The sensor 31 can be placed in the road paver e.g. in the control panel P or in a travel drive or it may sense a reference on the subgrade 7. In the control panel P or in the control system 25 an input section 27 may be provided for the input of parameters and/or for the display of parameters. The lifting cylinders 28 have assigned thereto at least one actuator 28′, e.g. a magnetically operated hydraulic valve. Furthermore, at least one sensor 30 may be provided as equipment for the road paver 1, the sensor sensing the temperature, density or consistency of the paving material, e.g. directly in front of the screed 3, and transmitting these values as information to the control system 25, if necessary. This sensed information could also be input by an operator. For instance, the screed 3 has disposed thereon at least one sensor 29 that senses the setting angle α of the screed relative to the subgrade 7. Sensor 29 could also sense the setting angle α on the traction arms 8. A plurality of sensors 29 can be provided across the pave width. Furthermore, a sensor 37 can be provided for sensing the pavement thickness S, the sensor sensing for instance the subgrade 7 or a reference (not shown) on the subgrade 7.

(36) In the road paver 1 or the screed 3, actuators are provided for setting the tamper stroke H or the tamper frequency F, respectively, and can be prompted by control signals generated by means of the control system 25 to implement control signals. For instance, FIG. 3 shows the mechanism 24 forming an actuator for the tamper stroke H for rotating the eccentric bushing 23 relative to the eccentric section 22. The adjustment of the tamper stroke H, which is each time matched to the pave parameters, is carried out automatically via the control system 25. The eccentric shaft 15 is rotationally driven for instance by a hydromotor 32. The speed thereof defines the tamper frequency F. A magnetically operated valve may serve as an actuator 33 for the hydromotor 3, i.e. a proportional current-regulating valve that can be actuated by the control system 25 with control signals.

(37) With the help of the control system 25 a plurality of different machine or site or paving-material parameters are automatically controlled depending on one another so as to minimize, for instance, error rates in the laid pavement 6 and to enhance the quality of the laid pavement 6.

(38) The tamper 14 has compacted the loosely pre-laid paving material 5 to such a degree that a bearing capacity is created that is adequate for the screed 3. It is only then that it is ensured that the screed 3 with its sole plate 18 is floatingly towed at an advantageous setting angle α. The tamper stroke H, the tamper frequency F, the paving speed V and the setting angle α depend on one another to a great degree. For instance, if the paving speed V is reduced, this will have an effect on the precompaction of the paving material at a constant tamper frequency and leveling cylinder adjustment. The bearing capacity of the paving material is increasing, so that the screed 3 is further floating and the setting angle α is decreasing. By contrast, if the paving speed is increased without increasing the tamper frequency, the bearing capacity of the paving material will decrease and the screed will perform the paving operation at a greater setting angle α, but at a smaller pavement thickness S. To minimize or avoid such influences on the final quality of the laid pavement 6, control variables for at least the compaction unit 13 and the tamper 14, respectively, are automatically controlled and regulated according to the invention by the control system 25 depending on the relevant processes or machine parameters. To be more specific, a uniform and optimal compaction of the paving material over the whole pave width of the screed is thereby achieved as a contribution to quality assurance.

(39) For instance, the setting angle α is sensed by means of the sensor 29 or a plurality of sensors 29 distributed in transverse direction and is transmitted to the control system 25 or a controller specifically in charge of this pave parameter so as to adapt the tamper stroke H upon change in the setting angle α, so that the setting angle α is returned again to an optimal value or cannot change significantly, thereby achieving the desired pavement thickness S with a permanently optimal precompaction.

(40) As a secondary aspect, the setting angle α may vary over the transverse paving width of the screed 3. The control system 25 can then adapt the tamper stroke H for each tamper 14 individually in a corresponding way, so that despite a pavement thickness S varying in a direction transverse to the pave travel direction the compaction remains uniform over the pave width.

(41) In consideration of the sensed setting angle α or the sensed changes thereof, it is furthermore possible to adapt the tamper stroke H and the tamper frequency F via the control system 25, and optionally additionally to adjust the leveling cylinders 10 in addition or as an alternative to an adaptation of the tamper frequency F.

(42) The tamper frequency F can be adapted in a particularly simple way in that upon change in the tamper stroke H the tamper frequency F is adapted automatically in conformity with a characteristic curve or in a characteristic map that is entered into or exists in the control system.

(43) A relevant paving parameter is e.g. also the density or consistency of the paving material 5. If the road paver 1 is equipped with a sensor 30, as mentioned, by means of which the density or consistency of the paving material can be sensed, the sensed value is compared with a target value and in case of a deviation from the target value an adaptation e.g. of the tamper stroke H and/or the tamper frequency F and/or the leveling cylinder setting is carried out via the control system 25 in such a way that upon deviation of the sensed density or consistency the setting angle is substantially maintained and the same compaction and evenness and thus quality of the pavement 6 is achieved.

(44) Likewise, the paving speed V is also an important paving parameter because in case of a change in paving speed an adaptation of the tamper stroke H and/or the tamper frequency F and/or the leveling cylinder setting, e.g. via the automatic control system 25, is needed.

(45) A further relevant paving parameter is the stiffness of the paving material 5 and/or the temperature thereof. These paving parameters can e.g. be sensed individually or in combination by means of the sensor 30 or a stiffness and a temperature sensor and transmitted to the control system 25, or after detection they can be entered by an operator on section 27, whereupon the control system, if recommended by the sensed values, adapts the tamper stroke H and/or the tamper frequency F and/or the leveling cylinder setting accordingly. As an additional or alternative adaptation, it is also possible to carry out an adjustment on the lifting cylinders 28, e.g. in order to relieve the screed 3 during the paving work to a greater extent or to load it particularly towards the subgrade 7, again with the intention to keep the setting angle α as uniform as possible and to make the screed 3 work with a uniform compaction of the pavement 6.

(46) In essence, such automation minimizes error rates and costs and improves the quality, a considerable work reduction for the operator(s) of the road paver being an automatic, but welcome, consequence of this method.