SCREED ASSEMBLY WITH FUNCTIONAL COUPLING BETWEEN A HEIGHT ADJUSTMENT DEVICE FOR A SCREED PLATE CARRIER AND A TILTING DEVICE FOR A SECONDARY SCREED PLATE ATTACHED TO THE SCREED PLATE CARRIER

Abstract

A screed assembly for a road paver comprises a main screed and a secondary screed. The main screed comprises a main screed plate for contact with paving material. The secondary screed comprises a screed plate carrier and a secondary screed plate for contact with the paving material. The secondary screed plate is attached to the screed plate carrier so as to be tiltable about a tilting axis. The screed assembly comprises a height adjustment device configured to lower or raise the screed plate carrier relative to the main screed. The screed assembly further comprises a tilting device configured to change a tilting angle of the secondary screed plate about the tilting axis.

Claims

1. A screed assembly for a road paver, comprising: a main screed with a main screed plate for contact with paving material; and a secondary screed with a screed plate carrier and a secondary screed plate for contact with the paving material; wherein the secondary screed plate is attached to the screed plate carrier so as to be tiltable about a tilting axis; wherein the screed assembly comprises a height adjustment device configured to lower or raise the screed plate carrier relative to the main screed; wherein the screed assembly comprises a tilting device configured to change a tilting angle of the secondary screed plate about the tilting axis; and wherein the height adjustment device and the tilting device a) are functionally coupled such that when the screed plate carrier is lowered or raised relative to the main screed by the height adjustment device, the tilting device is automatically actuated to change the tilting angle of the secondary screed plate about the tilting axis, and/or b) are functionally coupled such that when the tilting angle of the secondary screed plate about the tilting axis is changed by the tilting device, the height adjustment device is automatically actuated to lower or raise the screed plate carrier relative to the main screed.

2. The screed assembly according to claim 1, wherein the tilting axis extends transversely to a paving direction.

3. The screed assembly according to claim 1, wherein lowering the screed plate carrier by the height adjustment device actuates the tilting device for tilting the secondary screed plate about the tilting axis for increasing an angle of attack of the secondary screed plate with respect to a subgrade, and/or wherein raising the screed plate carrier by the height adjustment device actuates the tilting device for tilting the secondary screed plate about the tilting axis to reduce an angle of attack of the secondary screed plate with respect to a subgrade.

4. The screed assembly according to claim 1, wherein lowering the screed plate carrier by the height adjustment device actuates the tilting device for tilting the secondary screed plate about the tilting axis for reducing an angle of attack of the secondary screed plate with respect to a subgrade, and/or wherein raising the screed plate carrier by the height adjustment device actuates the tilting device for tilting the secondary screed plate about the tilting axis to increase an angle of attack of the secondary screed plate with respect to a subgrade.

5. The screed assembly according to claim 1, wherein an area of the secondary screed plate located at a rear in a paving direction is mounted on the tilting axis.

6. The screed assembly according to claim 1, wherein the tilting device is configured to raise or lower an end of the secondary screed plate opposite the tilting axis for changing the tilting angle of the secondary screed plate relative to the screed plate carrier.

7. The screed assembly according to claim 1, wherein the tilting device comprises an actuating connection connected to the secondary screed plate, wherein the actuating connection is configured to automatically rotate the secondary screed plate about the tilting axis when the screed plate carrier is lowered or raised by the height adjustment device.

8. The screed assembly according to claim 7, wherein the actuating connection is connected to a front area of the secondary screed plate with respect to a paving direction.

9. The screed assembly according to claim 1, wherein lowering or raising the screed plate carrier relative to the main screed by a carrier adjustment length actuates the tilting device to lower or raise a front end of the secondary screed plate relative to the screed plate carrier by a screed plate adjustment length, wherein the screed plate adjustment length is proportional to the carrier adjustment length.

10. The screed assembly according to claim 9, wherein a proportionality factor between the carrier adjustment length and the screed plate adjustment length corresponds at least substantially to a ratio between a length of the main screed plate in a paving direction and a length of the secondary screed plate in the paving direction.

11. The screed assembly according to claim 1, wherein the screed assembly comprises a drive configured to lower or raise the screed plate carrier relative to the main screed.

12. The screed assembly according to claim 11, wherein the drive is coupled to the tilting device and is configured to drive the tilting device.

13. The screed assembly according to claim 12, wherein the drive is configured to drive the height adjustment device with a first transmission ratio and to drive the tilting device with a second transmission ratio different from the first transmission ratio.

14. The screed assembly according to claim 1, further comprising a tilt adjustment device which allows changing the tilting angle of the secondary screed plate about the tilting axis without actuating the height adjustment device.

15. A road paver, comprising: a towing vehicle with a hopper located at a front of the towing vehicle in a paving direction for receiving paving material, and a screed assembly according to claim 1 attached to a rear of the towing vehicle in the paving direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In the following, embodiments according to the disclosure are explained in more detail with reference to the following drawings:

[0062] FIG. 1 shows a schematic side view of a road paver with a screed assembly according to one embodiment;

[0063] FIG. 2 shows a schematic top view of a screed assembly according to one embodiment;

[0064] FIG. 3 shows a schematic perspective view of a screed assembly according to one embodiment;

[0065] FIG. 4 shows a schematic view of the screed assembly of the embodiment shown in FIG. 3 in the area of the secondary screed, viewed in the opposite direction to the paving direction;

[0066] FIG. 5 shows a schematic view of the screed assembly of the embodiment shown in FIG. 3 in the area of the secondary screed viewed laterally towards the screed assembly;

[0067] FIG. 6 is a schematic view explaining the adjustment processes on a screed assembly according to one embodiment;

[0068] FIG. 7 shows a schematic view of a screed assembly according to an alternative embodiment viewed in the opposite direction to the paving direction;

[0069] FIG. 8 shows a schematic view of a screed assembly according to a further alternative embodiment, viewed in the opposite direction to the paving direction;

[0070] FIG. 9 shows a schematic view of a screed assembly according to a further alternative embodiment, viewed in the opposite direction to the paving direction; and

[0071] FIG. 10 shows a schematic view of a screed assembly according to a further alternative embodiment.

DETAILED DESCRIPTION

[0072] FIG. 1 shows a road paver 1 according to one embodiment. The road paver 1 comprises a towing vehicle 3 and a screed assembly 7 towed behind the towing vehicle 3 via towing bars 5. The screed assembly 7 is shown schematically in FIG. 1 and can be configured in accordance with all the embodiments described.

[0073] The towing vehicle 3 comprises a hopper 11 located at the front with respect to the paving direction 9 for receiving paving material. The paving material is transported to the rear by a material transport device of the towing vehicle 3 against the paving direction 9 and presented to the screed assembly 7. A transverse distribution device 13 in the form of a distributing auger is provided at the rear of the towing vehicle 3, which distributes the paving material in front of the screed assembly 7 along a transverse direction 14, which is parallel to a horizontal plane and perpendicular to the paving direction 9.

[0074] FIG. 2 shows a schematic top view of a screed assembly 7 according to one embodiment. The screed assembly 7 comprises a main screed 15 and two secondary screeds 17. In the embodiment shown, the screed assembly 7 is configured as an extending screed assembly. The secondary screeds 17 can be displaced along the transverse direction 14 relative to the main screed 15 in order to change the overall screed assembly width of the screed assembly 7. In FIG. 2, the right-hand secondary screed 17 as seen along the paving direction 9 is shown in a fully retracted state, in which it does not increase the overall screed assembly width of the screed assembly 7. The left-hand secondary screed 17 as seen along the paving direction 9 is shown in an extended state, in which it increases the overall screed assembly width of the screed assembly 7. Intermediate states are also conceivable.

[0075] In the embodiment shown in FIG. 2, the secondary screeds 17 are positioned in front of the main screed 15 with respect to the paving direction 9. Alternatively, the secondary screeds 17 could be positioned behind the main screed 15 with respect to the paving direction 9 or at least partially next to the main screed 15.

[0076] FIG. 3 shows a schematic perspective view of the screed assembly 7 according to one embodiment, viewed in the opposite direction to the paving direction 9. The screed assembly 7 is in the configuration shown in FIG. 2, that is, the left-hand secondary screed 17 viewed along the paving direction 9 is extended laterally and the right-hand secondary screed 17 viewed along the paving direction 9 is not extended. FIG. 3 shows displacement devices 19 with which the secondary screeds 17 can be moved along the transverse direction 14.

[0077] The secondary screeds 17 each comprise a secondary screed plate 21, which comes into contact with the paving material in order to compact and smooth it. Correspondingly, the main screed 15 comprises a main screed plate 23, which comes into contact with the paving material in order to compact and smooth it. In the embodiment shown, a length of the main screed screed plate 23 in the paving direction 9 corresponds to twice the length of the secondary screed plate 21 in the paving direction 9.

[0078] FIG. 4 shows a schematic view of the screed assembly 7 in the area of the extended secondary screed 17, viewed in the opposite direction to the paving direction 9. The secondary screed 17 comprises a support structure 25, which is provided at a fixed height in relation to the main screed 15. In addition, the secondary screed 17 comprises a screed plate carrier 27 (e.g., carrier frame). The secondary screed plate 21 is attached to the screed plate carrier 27. The screed plate carrier 27 is height-adjustably guided relative to the support structure 25 and thus relative to the main screed 15 via a guide structure 29. A height adjustment device 31 allows the screed plate carrier 27 to be raised and lowered relative to the support structure 25 and thus relative to the main screed 15. The height adjustment device 31 comprises a drive 33 in the form of a motor, which drives two identical spindle arrangements 35 in a synchronized manner via chains. The drive 33 is provided on a support frame 37. The spindles 35 are each configured as spindles with counter-rotating threads, which connect the screed plate carrier 27 and the support structure 25 to one another.

[0079] To lower the screed plate carrier 27 in relation to the main screed 15, the drive 33 drives the spindles 35 to increase the distance between the screed plate carrier 27 and the support frame 37 and the distance between the support frame 37 and the support structure 25. When the distance between the support frame 37 and the support structure 25 is increased by a first length, the distance between the support frame 37 and the screed plate carrier 27 is increased by a second length. The ratio between the first length and the second length results from a thread ratio of the corresponding spindle sections and is 1:1 in the embodiment shown.

[0080] To raise the screed plate carrier 27 relative to the support structure 25 and thus relative to the main screed 15, the drive 33 drives the spindles 35 to reduce the distance between the support frame 37 and the support structure 25 and the distance between the support frame 37 and the screed plate carrier 27. When the distance between the support frame 37 and the support structure 25 is reduced by a third length, the distance between the support frame 37 and the screed plate carrier 27 is reduced by a fourth length. The ratio between the third length and the fourth length results from a thread ratio of the corresponding spindle sections and is 1:1 in the embodiment shown.

[0081] FIG. 5 shows a schematic side view of the screed assembly 7 viewed along the transverse direction 14. As can be seen from FIG. 5, the screed assembly 7 can be inclined overall by means of an inclination adjustment 39 about an overall axis extending parallel to the transverse direction 14. The secondary screed plate 21 is attached to the screed plate carrier 27 so that it can tilt about a tilting axis 41. The connection between the secondary screed plate 21 and the tilting axis 41 is located in a rear area of the secondary screed plate 21 with respect to the paving direction 9.

[0082] As can be seen in FIG. 4, the support frame 37 and the secondary screed plate 21 are connected to each other with two identically configured actuating connections 43 (e.g., rods, bars, etc.). In particular, a front area of the screed plate 21 with respect to the paving direction 9 is connected to the support frame 37 via the actuating connections 43. The actuating connections 43 represent a tilting device 45 with which the secondary screed plate 21 can be tilted about the tilting axis 41.

[0083] Due to the fact that the actuating connection 43 is connected to the support frame 37, the height adjustment device 31 and the tilting device 45 are coupled.

[0084] When the screed plate carrier 27 is lowered by the height adjustment device 31, the support frame 37 moves downwards by the first length relative to the support structure 25. Thus, the front area of the secondary screed plate 21, which is connected to the support frame 37 via the actuating connection 43, also moves downwards relative to the support structure 25 by the first length. The screed plate carrier 27 and the tilting axis 41, and thus also the rear end of the secondary screed plate 21 with respect to the paving direction 9, on the other hand, move downwards by the sum of the first length and the second length. This results in the front end of the secondary screed plate 21 being raised relative to the rear end of the secondary screed plate 21 by the second length. When the screed plate carrier 27 is lowered, this results in a simultaneous tilting of the secondary screed plate 21 about the tilting axis 41 to increase an angle of attack between the secondary screed plate 21 and a horizontal plane or a subgrade.

[0085] When the screed plate carrier 27 is raised by the height adjustment device 31, the support frame 37 moves upwards by the third length relative to the support structure 25. Thus, the front area of the secondary screed plate 21, which is connected to the support frame 37 via the actuating connection 43, also moves upwards by the third length relative to the support structure 25. The screed plate carrier 27 and the tilting axis 41, and thus also the rear end of the secondary screed plate 21 with respect to the paving direction 9, on the other hand, move upwards by the sum of the third length and the fourth length. This results in a relative lowering of the front end of the secondary screed plate 21 relative to the rear end of the secondary screed plate 21 by the fourth length. When the screed plate carrier 27 is raised, this results in a simultaneous tilting of the secondary screed plate 21 about the tilting axis 41 to reduce an angle of attack between the secondary screed plate 21 and a horizontal plane or a subgrade.

[0086] FIG. 6 is a schematic view illustrating the application of the disclosure in a paving process. In part A of FIG. 6, the paving process is running in a state of equilibrium. Paving material is installed on a subgrade 47, wherein the installed pavement has a height level 49 behind the screed assembly 7. The height level 49 is defined by the height of the rear edge 51 of the main screed plate 23 and the height of the rear edge 53 of the secondary screed plate 21. The rear edge 51 of the main screed plate 23 and the rear edge 53 of the secondary screed plate 21 are at the same height in the equilibrium state shown in part A of FIG. 6. In part A of FIG. 6, a front edge 55 of the main screed plate 23 and a front edge 57 of the secondary screed plate 21 are also at a common height level, the height level 59, so that at least essentially the same compaction results in the area of the main screed 15 and in the area of the secondary screed 17.

[0087] Part B of FIG. 6 shows the situation after the screed assembly 7 has been rotated about an overall axis extending parallel to the transverse direction 14. This can occur, for example, due to changing properties of the paving material or due to a changing paving thickness. Due to the overall tilting of the screed assembly 7, the rear edge 51 of the main screed plate 23 and the rear edge 53 of the secondary screed plate 21 are no longer at the same height level. In the situation shown, the rear edge 51 of the main screed plate 23 is at a higher height level 61 than the height level 63 at which the rear edge 53 of the secondary screed plate 21 is located. This results in a gradation in the paving layer.

[0088] By actuating the height adjustment device 31 to raise the screed plate carrier 27, the rear edge 53 of the secondary screed plate 21 can be brought to the height level 61 of the rear edge 51 of the main screed plate 23 in order to produce a flat surface again. As explained above, when the screed plate carrier 27 is raised, both the secondary screed plate 21 is raised overall (arrow 65 in part B of FIG. 6) and the secondary screed plate 21 is tilted about the tilting axis 41 due to the coupling between the height adjustment device 31 and the tilting device 45, so that the angle of attack of the secondary screed plate 21 relative to the subgrade 47 is reduced (arrow 67 in part B of FIG. 6). The tilting axis 41 is essentially located in the area of the rear edge 53 of the secondary screed plate.

[0089] Part C of FIG. 6 shows the situation after the screed plate carrier 27 has been raised by the height adjustment device 31. The rear edge 53 of the secondary screed plate 21 has been raised to the height level 61 of the rear edge 51 of the main screed plate 23. At the same time, the secondary screed plate 21 was tilted about the tilting axis 41 so that the front edge 57 of the secondary screed plate 21 is at the same height level 69 as the front edge 55 of the main screed plate 23. This produces a flat surface again and with at least essentially constant compaction.

[0090] FIG. 7 shows an alternative embodiment. The embodiment shown in FIG. 7 essentially corresponds in its function and structure to the embodiment shown in FIGS. 3 to 5. For reasons of clarity, only the differences to the embodiment shown in FIGS. 3 to 5 are discussed. In the embodiment shown in FIG. 7, a tilt adjustment device 71 is provided between the actuating connections 43 and the support frame 37. The tilt adjustment device 71 allows the height of the actuating connections 43 to be adjusted in relation to the support frame 37 via a threaded rod 72 and rockers 74. The tilt adjustment device 71 thus allows the tilting angle of the secondary screed plate 21 about the tilting axis 41 to be changed, in particular manually, without actuating the height adjustment device 31. The tilt adjustment device 71 can be used, for example, to correct the tilting angle of the secondary screed plate 21.

[0091] FIG. 8 shows a further alternative embodiment. The embodiment shown in FIG. 8 essentially corresponds to the embodiment shown in FIG. 7 in terms of its function and structure. For reasons of clarity, only the differences to the embodiment shown in FIG. 7 are discussed. In the embodiment shown in FIG. 8, a tilt adjustment device 71 is also provided, which allows the tilting angle of the secondary screed plate 21 about the tilting axis 41 to be changed, in particular manually, without actuating the height adjustment device 31. In the embodiment shown in FIG. 8, however, this is not done by adjusting the height of the actuating connections 43 in relation to the support frame 37, but by tilting the actuating connections 43 out of a vertical orientation. The tilt adjustment device 71 comprises a threaded rod 72, which is mounted in bearings 76 for movement along the transverse direction 14. The actuating connections 43 are articulated to the threaded rod 72 at articulation points 78 so as to be rotatable about axes extending parallel to the paving direction 9. When the threaded rod 72 moves along the transverse direction 14, the articulation points 78 displace along the transverse direction 14, whereby the actuating connections 43 are inclined relative to a vertical direction and, due to the constant length of the actuating connections 43, a front area of the secondary screed plate 21 is raised or lowered relative to the supporting frame 37.

[0092] FIG. 9 shows a further alternative embodiment. The embodiment shown in FIG. 9 essentially corresponds in its function and structure to the embodiment shown in FIGS. 3 to 5. For reasons of clarity, only the differences to the embodiment shown in FIGS. 3 to 5 are discussed. In the embodiment shown in FIG. 9, the actuating connections 43 between the support frame 37 and the front area of the secondary screed plate 21 are not present. Instead, an actuating connection 81 is provided, which connects the front area of the secondary screed plate 21 to the support structure 25. The actuating connection 81 is a tilting device 45. The actuating connection 81 comprises a lever arrangement 83 with a lever 85 articulated to the screed plate carrier 27. If, when the screed plate carrier 27 is lowered or raised by the height adjustment device 31, a distance between the support structure 25 and the screed plate carrier 27 is changed, a position of the lever arrangement 83 changes so that the front area of the secondary screed plate 21 is raised or lowered. A configuration of the lever arrangement 83 adapted to a geometry of the screed assembly 7 ensures that when the screed plate carrier 27 is lowered or raised relative to the main screed 15 by the height adjustment device 31, the tilting device 45 is automatically actuated to change the tilting angle of the secondary screed plate 21 about the tilting axis 41, so that a difference between a draw-in height of the main screed plate 23 and a draw-in height of the secondary screed plate 21 is partially or completely compensated for.

[0093] In the embodiments described above, the coupling between the height adjustment device 31 and the tilting device 45 is mechanical. FIG. 10 schematically shows an alternative embodiment in which a height adjustment of the screed plate carrier 27 relative to the main screed 15 is coupled non-mechanically to an adjustment of the tilting angle of the secondary screed plate 21 about the tilting axis 41.

[0094] In the embodiment of FIG. 10, a tilting device 45 is provided with a drive 80 (e.g., motor, actuator, etc.) for changing the tilting angle of the secondary screed plate 21 about the tilting axis 41. In addition, a height adjustment device 31 with a drive 82 (e.g., motor, actuator, etc.) for lowering or raising the screed plate carrier 27 relative to the main screed 15 is provided. The drives 80, 82 are controlled by a control device 84. The control can be electronic or hydraulic, for example.

[0095] The embodiment according to FIG. 10 can be operated such that the control device 84 receives an operator input for lowering or raising the screed plate carrier 27 relative to the main screed 15. According to the operator input, the control device 84 can control the height adjustment device 31. In addition, the control device 84 can automatically control the tilting device 45 to tilt the secondary screed plate 21 based on the same operator input.

[0096] According to another variant, the control device 84 may receive an operator input for adjusting the tilting angle of the secondary screed plate 21 about the tilting axis 41. The control device 84 may control the tilting device 45 based on the operator input to change the tilting angle. In addition, the control device 84 may control the height adjustment device 31 based on the same operator input to raise or lower the screed plate carrier 27 relative to the main screed 15.

[0097] A ratio between changing a height of the screed plate carrier 27 in relation to the main screed 15 and changing the tilting angle can be predefined, in particular predefined in a variable manner.

[0098] As one skilled in the art would understand, the control device 84, as well an any other control, controller, control system, unit, sensor, device, system, subsystem, arrangement, or the like described herein may individually, collectively, or in any combination comprise appropriate circuitry, such as one or more appropriately programmed processors (e.g. one or more microprocessors including central processing units (CPU)) and associated memory, which may include stored operating system software and/or application software executable by the processor(s) for controlling operation thereof and/or for performing the particular algorithms represented by the various functions and/or operations described herein, including interaction and/or cooperation between any such control device, control, controller, control system, unit, sensor, device, system, subsystem, arrangement, or the like. One or more of such processors, as well as other circuitry and/or hardware, may be included in a single ASIC (Application-Specific Integrated Circuitry), or several processors and various circuitry and/or hardware may be distributed among several separate components, whether individually packaged or assembled into a SoC (System-on-a-Chip).