Tamper strip device of an installation plank and method for changing the stroke of a tamper strip device

Abstract

The invention relates to a tamper bar device (8) of a paving screed, in particular of a road finisher, comprising a tamper bar (10) arranged on at least one connecting rod (11) and a drive shaft (13) connected to the connecting rod (11) via an eccentric device (17). The eccentric device (17) is designed such that a first and a second stroke setting of the tamper bar (10) can be set by means of a thrust member (20) adjustable in the axial direction on the drive shaft (13). The thrust member (20) comprises a first region (201) arranged in the eccentric device (17) and a second region (202) arranged outside the eccentric device (17). The second region (202) is connected to an axial adjustment device (30) via an axial bearing (31). The invention further relates to a paving screed and a road finisher having such a tamper bar device.Finally, a further aspect of the invention lies in a method for changing the stroke of a tamper bar device.

Description

[0001] The invention relates to a tamper bar device of a paving screed, a paving screed, a road finisher and a method for changing the stroke of a tamper bar device according to the independent claims.

[0002] Such tamper bar devices are known in the prior art. For example, reference is made to EP 1 905 899 B1, EP 2 325 391 B1, EP 2 905 378 A1, and DE 10 2015 016 777 A1. Such tamper bar devices are used, particularly in road pavers, for pre-compaction and / or post-compaction of the paving material, usually asphalt, during the paving process. The tamper bar devices typically comprise at least one tamper bar arranged on at least one connecting rod, and a drive shaft connected to the connecting rod via an eccentric device and via which the drive movement is introduced into the tamper bar device. The drive shaft can be driven by a hydraulic or electric motor or an upstream driven drive gear.The conversion of the rotary motion around the rotational axis of the drive shaft into a tamping motion of the tamper bar is achieved via the eccentric device. This can, as frequently described in the prior art, comprise a so-called eccentric shaft, the key feature of which is that it has a transmission area eccentric with respect to the rotary shaft. Typical vertical strokes of the tamper bar, achieved using known eccentric devices, are often in the range of 1 mm to 10 mm.

[0003] During the installation process, it has been shown that different stroke paths can be advantageous, depending on factors such as the pavement thickness. The documents cited above already partially suggest the possibility of designing the eccentric device in such a way that a first and a second stroke setting for the tamper bar can be set depending on the direction of rotation of the drive shaft. By switching the direction of rotation of the drive shaft, at least two different stroke paths for the tamper bar can be easily achieved in these embodiments. If, for example, hydraulic or electric motors are used as the drive, this switching of the direction of rotation of the drive shaft is achieved easily. However, the switching is often very abrupt in this case, which sometimes represents a considerable load on the material.

[0004] Based on the prior art mentioned here, it is therefore the object of the invention to provide a tamper bar device with which one or more disadvantages of known tamper bar devices can be partially or completely overcome, so that a stroke adjustment is made possible in an improved manner.

[0005] The problem is solved with a tamper bar device, a paving screed, a road paver, and a method for varying the stroke of a tamper bar device according to the independent claims. Preferred developments are specified in the dependent claims.

[0006] According to one aspect of the invention, a tamper bar device of a paving screed, in particular of a road paver, is provided with a tamper bar. The tamper bar is arranged on at least one connecting rod. The tamper bar device comprises a drive shaft which is connected to the connecting rod via an eccentric device. The eccentric device is designed such that a first and a second stroke setting of the tamper bar can be set by means of a thrust member which is adjustable in the axial direction on the drive shaft. The thrust member has a first region which is arranged in the eccentric device. Furthermore, the thrust member has a second region which is arranged outside the eccentric device. The second region of the thrust member is connected to an axial adjustment device via an axial bearing.

[0007] A "thrust bearing" according to the present disclosure is understood to mean a bearing designed to absorb axially acting forces. Axial forces are forces that act in the longitudinal direction of a component, in this case, forces that act in the axial direction of the drive shaft. In other words, a thrust bearing is designed to transmit forces in the direction of a component axis, in this case, the drive shaft axis.

[0008] An "axial adjustment device" according to the present disclosure is understood to mean a device or apparatus designed to effect an adjustment in the axial direction of an element guided along an axis and to be adjusted, here the thrust member. In particular, the axial adjustment device is designed to effect the adjustment through a linear movement.

[0009] Typically, the thrust bearing is located between an adjusting ring mounted on the second portion of the thrust member and an adjusting element of the axial adjustment device. In particular, the adjusting ring is fixed axially on the second portion of the thrust member, so that axial forces acting on the adjusting ring are transmitted to the thrust member. The adjusting element of the axial adjustment device serves to transmit axial forces to the thrust member via the thrust bearing.

[0010] Preferably, a first end of the adjusting element, in particular a head end, is designed such that it at least partially encompasses the adjusting ring, which is advantageous for force transmission. For example, the head end of the adjusting element can be fork-shaped. The adjusting element can therefore also be referred to as a shift fork. A second end of the adjusting element is typically fixed to an axially adjustable rod of the axial adjustment device, wherein the rod runs parallel to the drive shaft. The adjusting movement of the rod can be a linear pushing movement, in particular in the direction of the longitudinal axis of the rod or push rod. Alternatively, a bushing can be arranged on the rod and is connected to a second end of the adjusting element. Typically, the rod is then designed as a spindle shaft and the bushing as a spindle nut, so that the spindle nut can be axially displaced by a rotational movement of the spindle shaft.This improves the torsional rigidity of the connection between the adjusting element and the rod, in particular the spindle shaft. To effect the axial adjustment, the axial adjusting device can, for example, have a manual or motor drive, in particular a spindle drive, which is designed to rotate the rod about its central longitudinal axis or, depending on the embodiment, to displace it axially, whereby an axial adjustment of the thrust member can be effected. For a motor drive, for example, an electric, pneumatic or hydraulic motor and / or one or more hydraulic or pneumatic cylinders or an electromagnetic actuator can be used. A manual drive, for example using a lever mechanism, is also possible and is encompassed by the invention.According to an alternative embodiment, instead of the axially adjustable rod, a switching lever may be provided which is operatively connected to the thrust member in order to provide an axial displacement of the thrust member.

[0011] The axial bearing, via which the thrust member is connected to the axial adjustment device, can be provided via one or more bearings. Specifically, for example, a first bearing and a second bearing can be provided between the adjusting ring and the actuating element, which are arranged opposite one another, preferably diametrically opposite one another. Preferably, the first bearing and the second bearing are plain bearings formed by plain bearing contact surfaces between the adjusting ring and the actuating element. Typically, the plain bearing contact surfaces of the adjusting ring and the actuating element consist of a plain bearing material, in particular a plain bearing plastic. According to one example, the adjusting ring consists entirely of a plain bearing material, in particular a plain bearing plastic (e.g., ultra-high molecular weight polyethylene [PE-UHMW]).Alternatively, it is also possible to construct plain bearings from a plain bearing plastic in combination with a metal, specifically as a metal-polymer composite plain bearing.

[0012] According to a preferred embodiment, a third bearing is provided between the adjusting ring and the actuating element, which is arranged between the first bearing and the second bearing. Typically, the third bearing is a plain bearing, which is designed similarly to the first and second plain bearings. The three bearings can also be designed identically to one another.

[0013] A plain bearing can be provided, for example, by an extension of the adjusting element that engages in a recess, in particular a groove, of the adjusting ring. In particular, the adjusting element can have one or more, in particular two or three, extensions that engage in a recess, in particular a groove, of the adjusting ring.

[0014] According to an alternative embodiment, one or more of the bearings provided between the adjusting ring and the adjusting element can be designed as rolling bearings, in particular axial rolling bearings.

[0015] In the circumferential direction between the first bearing and the second bearing, a contact-free area is typically provided between the adjusting ring and the actuating element.

[0016] According to the embodiments described herein, the desired stroke adjustment is achieved via a linear displacement of a thrust member along the longitudinal axis of the drive shaft. In particular, the eccentric device comprises a thrust member that is axially adjustable on the drive shaft via an axial adjustment device. The thrust member has a sliding slope on its outer circumferential surface that runs obliquely to the rotational axis of the drive shaft. According to the invention, the linear adjustment movement of the thrust member is used to adjust the eccentricity of the eccentric device.

[0017] The thrust member typically has a sliding bevel on its outer circumferential surface, which runs obliquely to the rotational axis of the drive shaft. The thrust member is therefore an element of the eccentric device, which is guided on the drive shaft via the axial adjustment device. To transmit the longitudinal movement of the thrust member into a stroke adjustment of the tamper bar, the thrust member has the sliding bevel, which runs in particular obliquely to the rotational axis of the drive shaft. The sliding bevel thus refers to a guide surface along which the eccentric ring is guided, as described in more detail below. The sliding bevel is ideally arranged on the outer circumferential surface or outer jacket surface of the thrust member. The sliding bevel can be formed to extend at least partially or completely around the circumference of the thrust member.In this case, the slope of the sliding bevel is determined along its longitudinal extension, specifically relative to a virtual reference plane in which the rotational axis of the drive shaft lies. The sliding bevel can be linear, although curved or more complex sliding bevel configurations are also encompassed by the invention. A linear sliding bevel is advantageous in that it is comparatively easy to manufacture and also enables reliable operation.

[0018] Furthermore, the eccentric device of the tamper bar device according to the invention typically has an eccentric ring mounted on the connecting rod. The eccentric ring has a receiving space for the thrust member with a sliding guide running on the sliding bevel of the thrust member. One task of the eccentric ring, in cooperation with the drive shaft or the eccentric device, is to generate an eccentricity that is picked up by the connecting rod and ultimately converted into a tamping movement of the tamper bar. The sliding guide rests on the sliding bevel of the thrust member. If the thrust member is now adjusted relative to the eccentric ring in the axial direction of the drive shaft, the sliding guide slides along the sliding bevel, ultimately resulting in a radial adjustment and thus an adjustment of the eccentricity of the eccentric ring. This ultimately results in a change in the tamper stroke.It goes without saying that the scope of the invention also includes embodiments in which the sliding guide and / or the sliding bevel have different sizes and / or extensions, in particular in the axial direction of the drive shaft. The sliding guide can therefore slide along the sliding bevel, which ultimately translates the movement in the axial direction of the drive shaft into a radial adjustment of the eccentric ring. The contact surface between the sliding bevel and the sliding guide can be kept relatively small in order to minimize friction, for example. However, in order to enable reliable and, in particular, tilt-free guidance, it is preferred if the sliding bevel and the sliding guide have a common contact surface which, viewed in the axial direction of the drive shaft, corresponds at least to the adjustment path of the thrust member and, in particular, is larger than the adjustment path of the thrust member.The eccentric ring ultimately also connects the connecting rod to the eccentric device and thus indirectly to the drive shaft.

[0019] To ensure that the thrust member has any freedom of movement relative to the eccentric ring, the eccentric ring is further designed to have a receiving space for the thrust member, within which the thrust member can be adjusted relative to the eccentric ring along the axis of rotation of the drive shaft as described in more detail below. Specifically, the receiving space is designed such that the thrust member is adjustable in the axial direction of the drive shaft between a first and a second stop position. When the thrust member is moved in the axial direction of the drive shaft by means of the adjusting device, it changes the eccentricity of the eccentric ring relative to the axis of rotation of the drive shaft via the sliding guide and the sliding bevel. Eccentricity is the distance, viewed in the radial direction, between the center point of the outer circumferential surface of the eccentric ring and the axis of rotation of the drive shaft.Ultimately, when the respective stop position is reached, the thrust member holds the eccentric ring in the first stroke setting in its first stop position via its sliding bevel and the eccentric ring in its second stop position in its second stroke setting. The thrust member typically rotates together with the drive shaft about its axis of rotation. The sliding bevel is thus designed in such a way that it not only effects the stroke adjustment or the change in the eccentricity of the eccentric ring relative to the drive shaft itself, but also maintains the respective stroke setting of the eccentric ring relative to the drive shaft. In this case, the receiving space refers to an area within which the thrust member can be adjusted along the drive shaft in the axial direction, essentially within the eccentric ring.

[0020] In interaction, it is therefore preferred if the eccentric device is designed such that an adjustment of the thrust member along the axis of rotation of the drive shaft is converted into an adjustment of the eccentric ring in the radial direction to the axis of rotation of the drive shaft. The thrust member forms a wedge whose degree of freedom of movement runs in the direction of the axis of rotation of the drive shaft. If this wedge is displaced in its position on the drive shaft relative to the eccentric ring, this results in a forced adjustment of the radial position of the eccentric ring relative to the drive shaft, which ultimately brings about the desired stroke adjustment. Because the freedom of movement of the thrust member along the drive shaft is limited by axially spaced stops, between which the adjustment range is defined, two defined end positions can be realized by the axially adjustable thrust member coupled to the axial adjustment device.According to the embodiments described herein, continuously variable intermediate positions can advantageously be provided between the stroke settings at the two end positions. Thus, the stroke of the tamper bar of the tamper bar device described herein can advantageously be continuously adjusted.

[0021] Preferably, the thrust member and the eccentric ring are essentially rotationally locked relative to one another in the direction of rotation of the drive shaft via a guide device and are simultaneously displaceable relative to one another along the drive shaft. Rotationally locked is to be understood as meaning that the thrust member is secured against rotation relative to the eccentric ring, particularly within the receiving space of the eccentric ring. This does not mean that there must be no play here. This is actually advantageous, for example, to enable the required longitudinal displaceability of the two elements relative to one another. It is important that the thrust member is not arranged so as to be freely and circumferentially rotatable in the eccentric ring and that it performs a defined adjustment movement relative to the eccentric ring via the guide device.The rotation lock is also advantageous in that it enables reliable transmission of the rotary movement of the drive shaft to the eccentric ring and thus to the connecting rod when the thrust member is in the first or second stop position.

[0022] The specific design of the guide device can vary. In principle, all axially displaceable shaft-hub connections are suitable, such as splined shaft connections (DIN 5461), polygonal shafts (DIN 32711), serrated profiles (DIN 5481), etc. However, it has proven advantageous if the guide device comprises a groove extending in the axial direction and an engagement element which engages in the groove, wherein the groove is arranged on the thrust member and the engagement element on the eccentric ring, or vice versa. The engagement element can in particular be a feather key fastened to the thrust member, in particular formed integrally with it, which projects beyond the outer circumferential surface of the thrust member in the radial direction into the groove on the eccentric ring. Alternatively, the thrust member can also have a receiving recess for a feather key in the outer circumferential surface in order to provide appropriate guidance.

[0023] In principle, it is possible to design the sliding slope as a projection element or similar. However, it is ideal if the sliding slope of the thrust element is formed by the outer surface of the thrust element itself. In this design, the thrust element thus rests almost completely with its outer surface against the inner surface of the receiving space of the eccentric ring. This also ultimately enables particularly reliable guidance of the thrust element relative to the eccentric ring.

[0024] Specifically, the outer surface of the thrust member can be cylindrical, in particular in the form of an oblique cylinder. A oblique cylinder is characterized by its two end faces running parallel to each other but not perpendicular to the outer surface of the cylinder or the cylinder axis. The thrust member is preferably arranged in the eccentric ring such that its cylinder axis intersects the rotational axis of the drive shaft at an acute angle, particularly at an angle of 3° to 15°, particularly 5° to 10°, and most particularly 7° to 9°. The angle is determined in a plane in which both the cylinder axis of the thrust member and the rotational axis of the drive shaft run.In the above-mentioned angular ranges, an optimal transmission of the displacement movement of the thrust member along the drive shaft into an adjustment movement of the eccentric ring in the radial direction of the drive shaft and a compact design for the desired stroke adjustment range is achieved.

[0025] It is preferred if the receiving space of the eccentric ring is designed as a hollow space that is essentially complementary to the outer surface of the thrust member. This also enables the thrust member and the eccentric ring to engage over as much of the surface area as possible. Accordingly, the eccentric ring has a hollow cylindrical receiving space for the thrust member, particularly one designed as a hollow, oblique cylinder. The cylinder axis of this cylindrical cavity ideally runs coaxially with the cylinder axis of the thrust member.

[0026] It is important that the thrust member is movable between two defined stop positions within the receiving space along the drive shaft. To ensure this, appropriate stops are preferably used. The receiving space is therefore ideally delimited on both sides in the axial direction of the drive shaft by stop walls. These can be formed partially by the eccentric ring itself, although from a design point of view it is preferred if the stop walls are provided by stop disks that are arranged separately from the eccentric ring. However, it can be provided that the stop disks are designed to be non-rotatably connected to the drive shaft and / or the eccentric ring. Furthermore, the two stops can serve as a vertical guide for the connecting rod. Furthermore, the two stops can serve to seal the receiving space so that the lubricant remains in this area and is not thrown out.

[0027] To transmit the eccentric rotational movement of the eccentric ring to the connecting rod, it is preferred if the eccentric ring is mounted on its outer side in a connecting rod bearing, particularly via a plain or roller bearing, so that it can rotate radially. The eccentric ring is thus freely rotatable relative to the connecting rod about the rotational axis of the drive shaft.

[0028] A further aspect of the invention lies in a paving screed for a road paver with a tamper bar device according to the invention. From a maintenance perspective, it is advantageous if all tamper bar devices present on the respective paving screed are designed according to the invention. In principle, however, it is preferred if at least two of the tamper bar devices according to the invention are present per tamper bar. In this way, a particularly uniform tamping movement can be ensured, in particular over the longitudinal extent of the tamper bar. For short tamper bars (for example, with a total length of 250 mm), a single tamper bar device may be sufficient.

[0029] The invention also relates to a road paver with a paving screed according to the invention. Road pavers are known in the prior art in their basic mode of operation. The essential task of a road paver is to distribute, compact, and smooth delivered paving material over the subsoil. The tamper bar device according to the invention is ideally driven by a drive source present on the road paver itself, for example, an internal combustion engine. It is particularly preferred if a secondary drive, such as a hydraulic motor or an electric motor, is driven via the primary drive, in particular the internal combustion engine. The secondary drive then drives, directly or indirectly, the drive shaft of the tamper bar device.

[0030] Finally, a further aspect of the invention lies in a method for changing the stroke of a tamper bar device, in particular a tamper bar device according to the invention. The method according to the invention comprises the steps described below.

[0031] A) Operating the tamper bar device with a first stroke setting using a rotating drive shaft. The starting point is thus a first stroke setting. In this state, the tamper bar of the tamper bar device tampes with a first stroke relative to the vertical direction.

[0032] In order to change the stroke of the tamper bar device, in a further step B) a thrust member on the drive shaft is adjusted along the rotation axis of the drive shaft via an axial adjustment device which is connected to the thrust member (20) via an axial bearing.

[0033] By adjusting the thrust element on the drive shaft along the rotational axis of the drive shaft, this leads in step C) to a conversion of the movement of the thrust element into an adjustment movement of an eccentric ring in the radial direction to the rotational axis of the drive shaft. This leads to a change in the eccentricity of the eccentric ring. This can be achieved, for example, by a wedge thrust gear or a comparable device with a sliding bevel and a sliding guide. It is therefore essential that the axial movement of the thrust element is used to effect a radial adjustment of the eccentric ring, whereby the thrust element and the eccentric ring are preferably coupled to one another via a gear system or as parts of a gear system. The extent of the adjustment depends, for example, on the gradient of the corresponding transmission bevels and ultimately also on the distance traveled by the thrust element along the drive shaft.

[0034] If the thrust member now hits an axial stop in step D), the eccentric ring has assumed its second end position.

[0035] Subsequently, in step E), the tamper bar device is operated with a second stroke setting by transferring the orbital movement of the drive shaft via the thrust member to the eccentric ring. The direction of rotation of the rotating drive shaft in the second stroke setting is identical to the direction of rotation of the rotating drive shaft in the first stroke setting.

[0036] It is possible for the thrust member to assume one or more intermediate positions between the first and second end positions. This allows the method according to the invention to also enable continuous tamper stroke adjustment and setting within the range defined by the two axially spaced end positions.

[0037] The invention is explained in more detail below with reference to the exemplary embodiments illustrated in the figures. The figures schematically show: Figure 1 : a road paver in side view; Figure 2A : a tamper bar device in perspective oblique view; Figure 2B : a drive shaft of the tamper bar device made of Figure 2A with an eccentric device in perspective oblique view; Figure 2C : an enlarged section of the tamper bar device from Figure 2A ; Figure 3 : a sectional view through the tamper bar device from Figure 2A ; Figure 4A : a detail enlargement from Figure 3 with large stroke at top dead center; and Figure 4B : the detail enlargement according to Figure 4A with small stroke at top dead center.

[0038] Identical components are identified by the same reference numerals in the figures, although not every component that is repeated in the figures is necessarily identified in every figure.

[0039] Figure 1 first illustrates the basic structure of a typical road paver 1. The essential elements of the road paver 1 are a hopper 2, a drive motor 3, a paving screed 4, travel devices 5 (wheeled and / or crawler tracks), and an operator's station 6. During paving operation, the road paver 1 moves in working direction A over the subsoil 9. The paving screed 4 is connected to the unspecified machine frame of the road paver 1 via drawbars 7. In addition to a smoothing function, the paving screed 4 also has a compaction function. For this purpose, a tamper bar device 8 is arranged on the paving screed 4 as an additional device. The following figures relate to the structure and function of this tamper bar device 8.

[0040] Figure 2A shows the tamper bar device in its entirety from a perspective oblique view from the front. During operation, the tamper bar device 8 is thus guided in the working direction A over the floor covering to be installed. The tamper bar device 8 typically comprises a tamper bar 10, a connecting rod 11, a connecting plate 12, a drive shaft 13, a holding arm 14 and an eccentric device 17. The tamper bar 10 is usually also equipped with a heating element. This is Figure 2A with the heating element 16. In the embodiment according to the Figure 2AThe tamping bar 10 is mounted on the screed via a total of two tamping bar devices 8 via the holding arms 14. The two tamping bar devices 8 are functionally identical. The movement of the tamping bar 10 is a tamping / lifting movement in the direction of the double arrow C. This movement is initiated by the drive shaft 13, which rotates clockwise or counterclockwise in the direction of rotation or rotational direction B around the rotation or rotational axis of the drive shaft 13. For this purpose, a corresponding drive device (not specified in more detail) is provided, such as an electric or hydraulic motor or a suitable transmission gear.

[0041] This centric rotational movement is converted into an eccentric rotational movement with the aid of the eccentric device 17 and transmitted to the connecting rods 11. The eccentric crank movement is ultimately converted into the desired tamping movement of the tamper bar 10 via the connecting plate 12. The tamper bar 10 is designed so as to be guided on the screed 4 (not shown in more detail in the figures). Corresponding guides are known in the art. Details on the design and functioning of the eccentric device 17 can be seen from the following figures. In particular, the eccentric device 17 is designed such that the lifting height, i.e. the extent of the tamping / lifting movement, is continuously adjustable in the direction of the double arrow C (or in the vertical direction). For this purpose, a thrust member 20 is provided on the drive shaft 13, which is axially adjustable and by means of which a first and a second stroke setting of the tamper bar 10 can be set.Typically, the thrust member 20 is a sleeve that is displaceable on the outer surface of the drive shaft 13.

[0042] As exemplified in the Figure 2B and 3 As shown, the thrust member 20 has a first region 201 and a second region 202. The first region 201 is arranged in the eccentric device 17. The second region 202 is arranged outside the eccentric device 17. The second region 202 is connected via an axial bearing 31 to an axial adjustment device 30, as shown, for example, in the Figure 2A , 2C and 3 is shown. In particular, the axial bearing 31 is provided between an adjusting ring 32, which is mounted on the second region 202 of the thrust member 20, and an adjusting element 33 of the axial adjustment device 30. For example, a first end 331 of the adjusting element 33 can at least partially encompass the adjusting ring 32, as shown in Figure 2Ccan be seen. The first end 331 of the actuating element 33 can also be referred to as the head or head end of the actuating element 33.

[0043] According to an embodiment, which can be combined with other embodiments described herein, at least a first bearing 311 and a second bearing 312 are provided between the adjusting ring 32 and the actuating element (33), as is shown by way of example in Figure 2Cis shown. In particular, the first bearing 311 and the second bearing 312 are arranged opposite one another, preferably diametrically opposite one another. Typically, at least one contact-free region 314 is provided in the circumferential direction between the first bearing 311 and the second bearing 312 between the adjusting ring 32 and the actuating element 33. Typically, the first bearing 311 and the second bearing 312 are plain bearings formed by plain bearing contact surfaces between the adjusting ring 32 and the actuating element 33. Typically, at least the plain bearing contact surfaces of the adjusting ring 32 and the actuating element 33 are made of plain bearing material, in particular plain bearing plastic.

[0044] As exemplified in Figure 2CAs shown, the adjusting element 33 can have one or more, in particular two or three, extensions 333. The extensions 333 are typically designed to engage in a recess 321, in particular a groove, of the adjusting ring 32. Typically, the groove is annular and provided on an outer circumferential surface of the adjusting ring 32. The surface of the groove typically consists of plain bearing material, in particular plain bearing plastic. According to one example, the adjusting ring 32 consists entirely of plain bearing material, in particular plain bearing plastic. Furthermore, the extensions 333 of the adjusting element 33 are typically made of plain bearing material, in particular plain bearing plastic. According to one example, the adjusting element 33 can consist entirely of plain bearing material, in particular plain bearing plastic.

[0045] According to an embodiment that can be combined with other embodiments described herein, a third bearing 313 is provided between the adjusting ring 32 and the actuating element 33, as shown by way of example in Figure 2C is shown. Typically, the third bearing 313 is arranged between the first bearing 311 and the second bearing 312. Preferably, the third bearing 313 is arranged centrally between the first bearing 311 and the second bearing 312. The third bearing 313 is typically a plain bearing and can be designed analogously to the first and second bearings.

[0046] According to an alternative embodiment, the first bearing 311 and / or the second bearing 312 and / or the third bearing 313 can be designed as rolling bearings, in particular axial rolling bearings. This is shown in the Fig. 4A given as an example for the area between the adjusting ring 32 and the adjusting element 33.

[0047] As exemplified in Fig. 2CAs shown, the adjusting element 33 is typically fixed to a rod 34 of the axial adjustment device 30. The rod 34 runs substantially parallel to the drive shaft 13. In other words, the rotation axis 131 of the drive shaft 13 and the central longitudinal axis 341 of the rod 34 are parallel to one another. Typically, a bushing 35 is arranged on the rod 34 and is connected to the second end 332 of the adjusting element 33. Typically, the rod 44 is designed as a spindle shaft and the bushing 35 as a spindle nut, so that the spindle nut is axially displaceable by a rotational movement of the spindle shaft. Typically, the rod 34 of the adjustment device 30 is connected to a manual or motor-driven spindle drive, which is designed to rotate the rod 34 about the central longitudinal axis 341, whereby an axial adjustment of the thrust member 20 can be effected.

[0048] Furthermore, in the Figure 2B and 3It can be seen that the essentially cylindrical thrust member 20 sits obliquely on the drive shaft 13. This means that the inner passage of the thrust member 20, which is complementary to the outer surface of the drive shaft 13, does not run along the cylinder axis Z of the cylindrical outer surface of the thrust member 20, but coaxially to the rotation axis B. This creates an oblique sliding surface with the outer surface of the thrust member, which interacts with the eccentric ring 18 in the manner described in more detail below.

[0049] Figure 2B further shows that the thrust member 20 in the present embodiment can have a receiving recess 29 for a key 21 located in the outer circumferential surface.

[0050] When the key 21 is arranged in the receiving recess 29, a projection 21 protruding radially from the outer surface of the thrust member is provided, which extends longitudinally in the direction of the cylinder axis Z and runs parallel to this on the outer surface of the thrust member 20. This projection ensures that the thrust member 20 is secured against rotation relative to the eccentric ring 18. Alternatively, the projection can also be provided as an integral component of the thrust member, i.e., without the receiving recess 29 and key 21.

[0051] On the left side in Figure 2B the connecting rod bearing 23 for the connecting rod is shown. Figure 2Bclarifies that the eccentric ring is also a sleeve-shaped component which is designed to run around the thrust member 20 (relative to the rotational axis B). In the eccentric ring 18 there is a guide groove 22 in which the projection of the thrust member 20, in particular the key 21, runs. As a result, the thrust member 20 and the eccentric ring 18 are rotationally fixed relative to one another relative to the rotational axis B of the drive shaft 13. At the same time, however, the thrust member can be adjusted in the axial direction of the rotational axis B and can thus be displaced in this direction relative to the eccentric ring 20. For this purpose, the corresponding guide groove is designed to be longer in terms of its length in the axial direction B than the total extension of the projection. Due to the inclined position of the outer circumferential surface of the thrust member 20 relative to the rotational axis B of the drive shaft, the eccentricity of the outer circumferential surface of the eccentric ring 18 is adjusted by such a longitudinal movement of the thrust member 20.In other words, the thrust adjustment of the thrust member 20 relative to the eccentric ring 18 changes the position of the contact surface between these two elements 18 and 20, thereby achieving a different eccentricity. This will be explained in more detail using the sectional views below. The eccentric orbital movement of the eccentric ring 18 is transferred to the connecting rod 11, which surrounds the eccentric ring on its outer surface. The existing eccentricity E is shown in the . Figures 4A and 4B by the position of the cylinder axis Z in relation to the outer surface of the eccentric ring 18 or the connecting rod bearing 11, which is also ring-shaped.

[0052] Figure 3 shows the embodiment according to Figure 2A in a sectional view in a vertical plane along the rotation axis B of the drive shaft 13 and Figure 4A the framed area of ​​a detail enlargement. The Figure 3 and 4aFirstly, it is clear that due to the above-described design of the thrust member 20 and the eccentric ring 18, a longitudinal movement of the thrust member 20 causes a radial adjustment of the eccentric ring 18 relative to the drive shaft 13. The oblique arrangement of the cylindrical surface of the thrust member 20 ultimately results in a sliding bevel 24 on the thrust member 20. The eccentric ring rests against this sliding bevel 24 with a correspondingly designed sliding guide, corresponding to its inner surface. If the relative position of the thrust member 20 is now adjusted along the rotational axis B of the drive shaft 13 relative to the eccentric ring 18, the eccentric ring 18 slides along the sliding bevel 24 of the thrust member 20 and thus raises or lowers relative to the rotational axis B. This adjustment movement is driven by the axial adjustment device 30, which is connected to the thrust member 20 via the axial bearing 31. Out of Figure 4AIt can be seen that the adjustment movement of the thrust member 20 can take place between the stops 26 and 27, which limit and seal the movement space or receiving space 28 within the eccentric ring 18 for the thrust member 20 in the axial direction of the rotation axis B on both sides.

[0053] The Figures 4A and 4B now concern the two extreme possible stroke settings in the present example. Figures 4A and 4B each show a sectional view through the eccentric device 17, when the connecting rod 11 or the eccentric device 17 has reached its top dead center. If the thrust member 20 in the present embodiment is displaced to the right on the drive shaft and strikes the stop 27 there, the distance in the horizontal plane, for example to the upper edge of the holder 14, is ΔH1 (this large stroke corresponds to twice the vertical distance between E and B in Fig. 4a). A rotational movement of the drive shaft 13 results in the eccentric ring 18 performing an eccentric rotational movement and thereby the connecting rod 11 and ultimately the Figure 4A The position of the eccentric ring axis E, ie the axis that forms the center axis of the outer circumferential surface of the eccentric ring, is shown in Figure 4A is also shown for further illustration. It is clearly evident that this axis runs parallel but not coaxial with the rotational axis B of the drive shaft 13.

[0054] If the thrust member 20 in the present embodiment is shifted to the left on the drive shaft, as is shown for example in Figure 4Bis shown, and strikes the stop 26 there, the distance in the horizontal plane, for example to the upper edge of the holder 14, is ΔH2. If the thrust member 20 is moved from right to left, the eccentric ring slides along its sliding guide on the sliding bevel of the thrust member 20 and approaches with its central axis Z the rotation axis B of the drive shaft 13. This continues until the movement of the thrust member 20 along the drive shaft 13 is stopped by the stop 26. If the drive shaft 13 is in the Fig. 4B shown position, the eccentric ring 18 rotates around the drive shaft 13 with the reduced stroke ΔH2.

[0055] A possible alternative embodiment, which is also encompassed by the invention, consists, for example, in the Fig. 3The adjusting element 33 shown is to be firmly connected to the rod 34 and, for axial adjustment, the rod 34 is to be moved linearly in the axial direction. Instead of a rotational adjustment movement of the rod 34, in this case the rod 34 is thus moved in the axial direction or preferably parallel to the direction of rotation B. The spindle nut 35 and the design of the rod 34 as a threaded rod are then not required.

[0056] The rotary or linear adjustment movement of the rod 34 can be driven by a motor, for example, an electric, pneumatic, or hydraulic motor, by means of a suitable actuator, for example, a pneumatic or hydraulic cylinder or an electromagnetic actuator, or manually, for example, by means of a hand crank and / or a suitable lever mechanism. The rod 34 can also be designed, for example, as a rack. The corresponding drive device can be operatively connected to the rod 34, in particular at at least one or both of its axial ends.

[0057] As can be seen from the embodiments described herein, a tamper bar device is advantageously provided that enables stroke adjustment in an improved manner. The possibility of continuous adjustment is particularly advantageous. Furthermore, stroke adjustment is enabled, allowing material stress during the adjustment process to be reduced compared to solutions known from the prior art. LIST OF REFERENCE SYMBOLS

[0058] 1 Road paver 2 Hopper 3 Drive motor 4 Screed 5 Driving equipment 6 Operator's station 7 Draw arms 8 Tamper bar device 9 Ground surface 10 Tamper bar 11 Connecting rod 12 Connecting plate 13 Drive shaft 131 Rotation axis of the drive shaft 14 Holding arm 15 Middle section 17 Eccentric device 18 Eccentric ring 20 Thrust link 201 First section of the thrust link 202 Second section of the thrust link 21 Projection / key 22 Guide groove 23 Connecting rod bearing 24 Sliding bevel 26 Stop 27 Stop 29 Recess 30 Axial adjustment device 31 Axial bearing 311 First bearing 312 Second bearing 313 Third bearing 314 Non-contact area 315 Roller bearing 32 Adjusting ring 321Recess / annular groove 33Adjusting element 331First end of the adjusting element 332Second end of the adjusting element 333Extensions 34Rod 341Central axis of the rod 35Bushing AWorking direction BDirection of rotation CPilling / lifting movement

Claims

1. Tamper bar device (8) of a paving screed (4), in particular of a road finisher (1), with a tamper bar (10) which is arranged on at least one connecting rod (11), with a drive shaft (13) which is connected to the connecting rod (11) via an eccentric device (17), wherein the eccentric device (17) is designed such that a first and a second stroke setting of the tamper bar (10) can be set by means of a thrust member (20) which is adjustable in the axial direction on the drive shaft (13), characterized by that the thrust member (20) comprises a first region (201) arranged in the eccentric device (17) and a second region (202) arranged outside the eccentric device (17), wherein the second region (202) is connected to an axial adjustment device (30) via an axial bearing (31).

2. Tamper bar device (8) according to claim 1, wherein the axial bearing (31) is provided between an adjusting ring (32) mounted on the second portion (202) of the thrust member (20) and an adjusting element (33) of the axial adjusting device (30).

3. Tamper bar device (8) according to claim 2, wherein a first end (331), in particular a head, of the adjusting element (33) at least partially encompasses the adjusting ring (32).

4. Tamper bar device (8) according to one of claims 2 or 3, wherein a first bearing (311) and a second bearing (312) are provided between the adjusting ring (32) and the adjusting element (33), in particular wherein the first bearing (311) and the second bearing (312) are arranged opposite one another, preferably diametrically opposite one another, and wherein a contact-free region (314) is provided between the adjusting ring (32) and the adjusting element (33) in the circumferential direction between the first bearing (311) and the second bearing (312).

5. Tamper bar device (8) according to claim 4, wherein the first bearing (311) and the second bearing (312) are plain bearings formed by plain bearing contact surfaces between the adjusting ring (32) and the adjusting element (33).

6. Tamper bar device (8) according to claim 5, wherein at least the plain bearing contact surfaces of the adjusting ring (32) and the adjusting element (33) consist of plain bearing material, in particular plain bearing plastic, in particular wherein the adjusting ring (32) consists entirely of plain bearing material, in particular plain bearing plastic.

7. Tamper bar device (8) according to one of claims 4 to 6, wherein a third bearing (313) is provided between the adjusting ring (32) and the adjusting element (33), which third bearing (313) is arranged between the first bearing (311) and the second bearing (312), in particular wherein the third bearing (313) is a plain bearing.

8. Tamper bar device (8) according to one of claims 2 to 7, wherein the adjusting element (33) has one or more, in particular two or three, extensions (333) which engage in a recess (321), in particular a groove, of the adjusting ring (32).

9. Tamper bar device (8) according to one of claims 2 to 4, wherein the first bearing (311) and the second bearing (312) are rolling bearings (315).

10. Tamper bar device (8) according to one of claims 2 to 9, wherein the adjusting element (33) is fixed to a rod (34) of the axial adjusting device (30), wherein the rod (34) runs substantially parallel to the drive shaft (13).

11. Tamper bar device (8) according to claim 10, wherein a bushing (35) is arranged on the rod (34) and is connected to a second end (332) of the actuating element (33).

12. Tamper bar device (8) according to one of the preceding claims, wherein the axial adjustment device (30) has a manual or motor drive, in particular a spindle drive, for axial adjustment.

13. Paving screed (4) for a road finisher with a tamper bar device (8) according to one of claims 1 to 12.

14. Screed (4) according to claim 13, characterized in that it has a tamping bar (10) which is mounted and driven by at least two of the tamping bar devices (8) according to one of claims 1 to 11.

15. Road paver (1) with a paving screed (4) according to one of claims 13 or 14.

16. A method for changing the stroke of a tamper bar device (8), in particular according to one of claims 1 to 12, comprising the steps: a) operating the tamper bar device (8) with a first stroke setting with a rotating drive shaft (13); b) adjusting a thrust member (20) on the drive shaft (13) along the axis of rotation (131) of the drive shaft (13) via an axial adjusting device (30) which is connected to the thrust member (20) via an axial bearing (31); c) converting the movement of the thrust member (20) along the drive shaft (13) into an adjusting movement of an eccentric ring (18) in the radial direction to the axis of rotation (131) of the drive shaft (13); d) striking the thrust member (20) against an axial stop;and e) operating the tamper bar device (8) with a second stroke setting by transmitting the orbital movement of the drive shaft (13) via the thrust member (20) to the eccentric ring (18), wherein the direction of rotation of the rotating drive shaft (13) in the second stroke setting is identical to the direction of rotation of the rotating drive shaft (13) in the first stroke setting;

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