Tamper bar device of a built-in plank and 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 paver and a method for changing the stroke of a tamper bar device according to the independent claims.

[0002] Such tamping bar devices are known in the prior art. Reference is made, for example, to EP 1 905 899 B1, EP 2 325 391 B1, EP 2 905 378 A1, and DE 10 2015 016 777 A1. These tamping 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 tamping bar devices typically comprise at least one tamping bar arranged on at least one connecting rod and a drive shaft connected to the connecting rod via an eccentric mechanism, through which the drive motion is introduced into the tamping bar device. The drive shaft can be powered by a hydraulic or electric motor or by an upstream driven drive gearbox.The conversion of the rotary motion around the drive shaft's axis of rotation into a tamping motion of the tamper bar is achieved via the eccentric device. As frequently described in the prior art, this can include a so-called eccentric shaft, the essential characteristic of which is that it has a transmission range eccentric to the rotary shaft. Typical strokes of the tamper bar in the vertical direction, obtained via known eccentric devices, are often in the range of 1 mm to 10 mm.

[0003] During the installation process, it has become apparent that different stroke lengths can be advantageous depending on factors such as the surface thickness. The aforementioned publications already partially propose the possibility of designing the eccentric mechanism in such a way that a first and a second stroke setting of the tamping bar can be adjusted 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 lengths of the tamping bar can thus be easily achieved in these designs. If, for example, hydraulic or electric motors are used as the drive, this switching of the drive shaft's direction of rotation is easily accomplished. However, the switching process is often very abrupt, which can result in considerable material stress.

[0004] Based on the aforementioned prior art, the object of the invention is therefore 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 stroke adjustment is made possible in an improved manner.

[0005] The problem is solved using a tamping bar device, a paving screed, a road paver, and a method for changing the stroke of a tamping bar device according to the independent claims. Preferred embodiments are specified in the dependent claims.

[0006] According to one aspect of the invention, a tamper bar device for a screed, in particular for a 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 adjusted by means of a thrust member that is axially adjustable on the drive shaft. The thrust member has a first section which is arranged in the eccentric device. Furthermore, the thrust member has a second section which is arranged outside the eccentric device. The second section of the thrust member is connected to an axial adjustment device via a thrust bearing.

[0007] According to the present disclosure, an "axial bearing" is a bearing designed to absorb axially acting forces. Axial forces are forces acting in the longitudinal direction of a component, in this case, forces acting in the axial direction of the drive shaft. In other words, an axial bearing is designed to transmit forces in the direction of a component axis, here the drive shaft axis.

[0008] An "axial adjustment device" according to the present disclosure is understood to be a device or apparatus designed to effect an axial adjustment of an element, here the push member, which is guided and adjustable along an axis. In particular, the axial adjustment device is designed to effect the adjustment by means of a linear movement.

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

[0010] Preferably, a first end of the adjusting element, in particular a head end, is designed such that it at least partially engages 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 switching fork. A second end of the adjusting element is typically fixed to an axially adjustable rod of the axial adjusting device, the rod running parallel to the drive shaft. The adjusting movement of the rod can be a linear thrust 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, which 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, particularly the spindle shaft. To effect axial adjustment, the axial adjusting device can, for example, have a manual or motorized drive, in particular a spindle drive, configured to rotate the rod about its central longitudinal axis or, depending on the embodiment, to displace it axially, thereby effecting axial adjustment of the push member. For a motorized 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 included in the invention.According to an alternative embodiment, instead of the axially adjustable rod, a shift lever can be provided which is operatively connected to the push member in order to provide an axial displacement of the push member.

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

[0012] According to a preferred embodiment, a third bearing is provided between the adjusting ring and the adjusting element, positioned between the first and second bearings. Typically, the third bearing is a plain bearing designed similarly to the first and second plain bearings. The three bearings can also be identical to each other.

[0013] A sliding bearing can be provided, for example, by a projection 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, projections 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 adjusting element.

[0016] According to the embodiments described herein, the desired stroke adjustment is achieved by a linear displacement of a push element along the longitudinal axis of the drive shaft. In particular, the eccentric device is provided to have a push element that is adjustable axially on the drive shaft via an axial adjustment device, wherein the push element has a sliding chamfer on its outer circumferential surface that runs obliquely to the axis of rotation of the drive shaft. According to the invention, the linear adjustment movement of the push element is used to adjust the eccentricity of the eccentric device.

[0017] The push member typically has a sliding ramp on its outer circumferential surface, which runs obliquely to the axis of rotation of the drive shaft. The push member is thus an element of the eccentric mechanism, guided on the drive shaft by the axial adjustment device. To transmit the longitudinal movement of the push member into a stroke adjustment of the tamper bar, the push member features the sliding ramp, which runs obliquely to the axis of rotation of the drive shaft. The sliding ramp therefore defines a guide surface along which the eccentric ring is guided, as described in more detail below. Ideally, the sliding ramp is located on the outer circumferential surface or outer surface of the push member. The sliding ramp can extend at least partially or completely around the push member.The slope of the sliding ramp is determined in this case along its longitudinal extent, specifically with respect to a virtual reference plane in which the axis of rotation of the drive shaft lies. The sliding ramp can be linear, but curved or more complex sliding ramp profiles are also included in the invention. A linear sliding ramp profile is advantageous because it is relatively easy to manufacture and also enables reliable operation.

[0018] Furthermore, the eccentric device of the tamper bar assembly according to the invention typically includes an eccentric ring mounted on the connecting rod. The eccentric ring has a receiving space for the push member with a sliding guide running on the sliding surface of the push member. One function of the eccentric ring is to generate an eccentricity in conjunction with the drive shaft or the eccentric device, which is picked up by the connecting rod and ultimately converted into a tamping motion of the tamper bar. The sliding guide rests against the sliding surface of the push member. If the push member is now adjusted relative to the eccentric ring in the axial direction of the drive shaft, the sliding guide slides along the sliding surface, resulting in a radial adjustment and thus an adjustment of the eccentricity of the eccentric ring. This ultimately changes the tamper stroke.It is understood that the scope of the invention also includes embodiments in which the sliding guide and / or the sliding ramp have different sizes and / or extents, particularly in the axial direction of the drive shaft. The sliding guide can thus slide along the sliding ramp, ultimately converting the axial movement of the drive shaft into a radial adjustment of the eccentric ring. The contact area between the sliding ramp and the sliding guide can be kept relatively small, for example, to minimize friction. However, to enable reliable and, in particular, jam-free guidance, it is preferred if the sliding ramp 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 travel of the push member and, in particular, is larger than the adjustment travel of the push member.The eccentric ring ultimately also connects the connecting rod to the eccentric device and thus indirectly to the drive shaft.

[0019] To allow for any movement of the push member relative to the eccentric ring, the eccentric ring is designed to have a receiving space for the push member. Within this space, the push member can adjust itself along the axis of rotation of the drive shaft relative to the eccentric ring in the manner described in more detail below. Specifically, the receiving space is designed such that the push member is adjustable in the axial direction of the drive shaft between a first and a second stop position. When the push member is moved in the axial direction of the drive shaft by means of the adjustment 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 ramp. Eccentricity is defined here as the distance of the radially measured center point of the outer circumferential surface of the eccentric ring relative to the axis of rotation of the drive shaft.Ultimately, once the respective stop position is reached, the push member, via its sliding ramp, holds the eccentric ring in its first stroke setting in its first stop position and in its second stop position, holding it in its second stroke setting. The push member typically rotates together with the drive shaft around its axis of rotation. The sliding ramp 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. The receiving space, in this context, refers to an area within which the push member is adjustable axially along the drive shaft, essentially within the eccentric ring.

[0020] In combination, it is therefore preferred if the eccentric device is designed such that an adjustment of the push 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 push member forms a wedge whose degree of freedom extends in the direction of the axis of rotation of the drive shaft. If this wedge is displaced relative to the eccentric ring on the drive shaft, this results in a forced adjustment of the radial position of the eccentric ring relative to the drive shaft, which ultimately achieves the desired stroke adjustment. Because the freedom of movement of the push 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 push member coupled to the axial adjustment device.Between the stroke settings at the two end positions, stepless intermediate positions can advantageously be provided according to the embodiments described herein. Thus, the stroke of the tamper bar of the tamper bar device described herein can advantageously be adjusted steplessly.

[0021] Preferably, the push member and the eccentric ring are essentially rotationally locked relative to each other in the direction of rotation of the drive shaft by means of a guide device, while simultaneously being displaceable relative to each other along the drive shaft. Rotational locking is understood to mean that the push member is secured against rotation, particularly within the receiving space of the eccentric ring. This does not mean that there must be no play. This is even advantageous, for example, to allow the necessary longitudinal displacement of the two elements relative to each other. It is important that the push member is not freely rotatable within the eccentric ring and performs a defined adjustment movement relative to the eccentric ring via the guide device.The rotary locking mechanism is also advantageous in that it enables a reliable transmission of the rotary motion of the drive shaft to the eccentric ring and thus to the connecting rod when the push 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), polygon shafts (DIN 32711), serrated spline profiles (DIN 5481), etc. However, it has proven advantageous if the guide device comprises an axially extending groove and an engagement element that engages in the groove, with the groove being located on the thrust member and the engagement element on the eccentric ring, or vice versa. The engagement element can be, in particular, a key attached to the thrust member, especially one formed integrally with it, which projects radially into the groove on the eccentric ring via the outer surface of the thrust member. Alternatively, the thrust member can also have a receiving recess in its outer surface for a key to provide suitable guidance.

[0023] In principle, the sliding ramp can be designed as a projection or similar feature. Ideally, however, the sliding ramp of the push member is formed by the outer surface of the push member itself. In this embodiment, the push member thus rests almost entirely against the inner surface of the eccentric ring's receiving chamber with its outer surface. This also ultimately results in particularly reliable guidance of the push member relative to the eccentric ring.

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

[0025] It is preferred that the receiving space of the eccentric ring be designed as a cavity substantially complementary to the outer surface of the shear member. This also enables the most complete possible contact between the shear member and the eccentric ring. Accordingly, the eccentric ring has a hollow cylindrical receiving space for the shear member, particularly one designed as a hollow skewed cylinder. The axis of this cylindrical cavity ideally runs coaxially with the axis of the shear 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, suitable stops are preferably used. The receiving space is therefore ideally bounded on both sides in the axial direction of the drive shaft by stop walls. These can be partially formed by the eccentric ring itself; however, from a design perspective, it is preferable if the stop walls are formed by stop discs that are arranged separately from the eccentric ring. It is also possible for the stop discs to be rotationally fixed to the drive shaft and / or the eccentric ring. Furthermore, the two stops can serve as vertical guides for the connecting rod. Additionally, the two stops can act as seals for the receiving space, so that the lubricant remains in this area and is not flung out.

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

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

[0029] The invention also relates to a road paver with a screed according to the invention. The basic operating principle of road pavers is known in the prior art. The essential task of a road paver is to distribute, compact, and smooth delivered material on the subgrade. Ideally, the drive of the tamping blade assembly according to the invention is provided by a drive source located 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 by the primary drive, in particular the internal combustion engine. The secondary drive then drives, directly or indirectly, the drive shaft of the tamping blade assembly.

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

[0031] In order to change the stroke of the tamper bar device, in a further step B) a push member on the drive shaft is adjusted along the axis of rotation of the drive shaft via an axial adjustment device which is connected to the push member (20) via an axial bearing.

[0032] By adjusting the pushrod on the drive shaft along the axis of rotation of the drive shaft, step C) converts the movement of the pushrod into an adjustment movement of an eccentric ring in the radial direction relative to the axis of rotation of the drive shaft. This results in a change in the eccentricity of the eccentric ring. This can be achieved, for example, by a wedge-type pushrod or a comparable device with a sliding ramp and a sliding guide. It is therefore essential that the axial movement of the pushrod is used to effect a radial adjustment of the eccentric ring, with the pushrod and the eccentric ring preferably being coupled to each other via a gearbox or as components of a gearbox. The extent of the adjustment depends, for example, on the slope of the corresponding transmission ramps and ultimately also on the path of travel of the pushrod along the drive shaft.

[0033] If, in step D), the push element now strikes an axial stop, the eccentric ring has assumed its second end position.

[0034] In step E), the tamper bar device is then operated with a second stroke setting by transferring the rotational movement of the drive shaft via the push link to the eccentric ring. The direction of rotation of the drive shaft in the second stroke setting is identical to the direction of rotation of the drive shaft in the first stroke setting.

[0035] It is possible for the push 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 stepless adjustment and fixing of the tamper stroke within the range defined by the two end positions spaced apart axially.

[0036] The invention is explained in more detail below with reference to the exemplary embodiments shown in the figures. The figures schematically illustrate: 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 a perspective oblique view; Figure 2C: an enlarged section of the tamper bar device made of Figure 2A Figure 3: a sectional view through the tamper bar device made of Figure 2A Figure 4A: a close-up detail from Figure 3 with large stroke at top dead center; and Figure 4B: the section enlargement according to Figure 4A with a small stroke at top dead center.

[0037] Identical components are marked with the same reference symbols in the figures, although not every component that is repeated in the figures is necessarily labelled in every figure.

[0038] Figure 1 Figure 1 illustrates the basic structure of a typical road paver 1. Essential elements of the road paver 1 are a hopper 2, a drive motor 3, a screed 4, travel mechanisms 5 (wheeled and / or tracked undercarriages), and an operator's platform 6. During paving operation, the road paver 1 moves in the working direction A over the subgrade 9. The screed 4 is connected to the unspecified machine frame of the road paver 1 via drawbars 7. In addition to a smoothing function, the screed 4 also performs a compaction function. For this purpose, a tamping bar device 8 is attached to the screed 4. The following figures describe the structure and operation of this tamping bar device 8.

[0039] Figure 2AThe tamping bar assembly is initially shown in its entirety from a perspective oblique view from a front angle. During operation, the tamping bar assembly 8 is thus guided in the working direction A over the floor covering to be installed. The tamping bar assembly 8 typically comprises a tamping bar 10, a connecting rod 11, a connecting plate 12, a drive shaft 13, a support arm 14, and an eccentric device 17. The tamping bar 10 is also usually equipped with a heating element. This is shown in Figure 2A with the heating element 16 specified. In the exemplary embodiment according to the Figure 2AThe tamping bar 10 is mounted on the screed via two tamping bar assemblies 8 and the retaining arms 14. The two tamping bar assemblies 8 are functionally identical. The movement of the tamping bar 10 is a tamping / lifting motion 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 reversal B around the axis of rotation or reversal of the drive shaft 13. A suitable drive device, not further specified, such as an electric or hydraulic motor or a suitable transmission unit, is provided for this purpose.

[0040] This centric rotational movement is converted into an eccentric rotational movement by means 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 tamping bar 10 via the connecting plate 12. The tamping bar 10 is guided accordingly on the installation plank 4 (not shown in detail in the figures). Such guides are known in the prior art. Details of the design and function of the eccentric device 17 are shown in the following figures. In particular, the eccentric device 17 is designed such that the stroke 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 link 20, adjustable axially on the drive shaft 13, is provided, by means of which a first and a second stroke setting of the tamping bar 10 can be adjusted.Typically, the push member 20 is a sleeve that is slidable on the outer cylindrical surface of the drive shaft 13.

[0041] As exemplified in the Figure 2B and 3 As shown, the thrust member 20 has a first section 201 and a second section 202. The first section 201 is arranged in the eccentric device 17. The second section 202 is arranged outside the eccentric device 17. The second section 202 is connected via a thrust bearing 31 to an axial adjustment device 30, as is found, for example, in the Figure 2A , 2C and 3 as 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 actuating element 33 of the axial adjustment device 30. For example, a first end 331 of the actuating element 33 can at least partially engage the adjusting ring 32, as shown in Figure 2CThe first end 331 of the actuating element 33 can also be referred to as the head or head end of the actuating element 33.

[0042] According to one 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 adjusting element (33), as exemplified in Figure 2CAs shown, the first bearing 311 and the second bearing 312 are arranged opposite each other, preferably diametrically opposite each other. Typically, at least one contact-free area 314 is provided in the circumferential direction between the first bearing 311 and the second bearing 312, between the adjusting ring 32 and the adjusting 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 adjusting element 33. Typically, at least the plain bearing contact surfaces of the adjusting ring 32 and the adjusting element 33 consist of a plain bearing material, in particular a plain bearing plastic.

[0043] 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 surface of the adjusting ring 32. The surface of the groove typically consists of a sliding bearing material, in particular a sliding bearing plastic. According to one example, the adjusting ring 32 consists entirely of a sliding bearing material, in particular a sliding bearing plastic. Furthermore, the extensions 333 of the adjusting element 33 are typically made of a sliding bearing material, in particular a sliding bearing plastic. According to another example, the adjusting element 33 can consist entirely, or at least the adjusting element head, of a sliding bearing material, in particular a sliding bearing plastic.

[0044] According to one embodiment, which can be combined with other embodiments described herein, a third bearing 313 is provided between the adjusting ring 32 and the adjusting element 33, as exemplified in Figure 2C As shown, the third bearing 313 is typically 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.

[0045] 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 described in the Fig. 4A The area between the adjusting ring 32 and the adjusting element 33 is shown as an example.

[0046] As exemplified in Fig. 2CAs shown, the adjusting element 33 is typically fixed to a rod 34 of the axial adjusting device 30. The rod 34 runs essentially parallel to the drive shaft 13. In other words, the axis of rotation 131 of the drive shaft 13 and the central longitudinal axis 341 of the rod 34 are parallel to each other. 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 adjusting device 30 is connected to a manual or motorized spindle drive configured to rotate the rod 34 about the central longitudinal axis 341, thereby effecting an axial adjustment of the push member 20.

[0047] Furthermore, in the Figure 2B and 3It is evident that the essentially cylindrical push member 20 sits obliquely on the drive shaft 13. This means that the inner passage of the push 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 push member 20, but rather coaxially with the axis of rotation B. This results in an inclined sliding surface with the outer surface of the push member, which interacts with the eccentric ring 18 in the manner described in more detail below.

[0048] Figure 2B further shows that the push member 20 in the present embodiment can have a receiving recess 29 in the outer surface for a key 21.

[0049] When the key 21 is positioned in the receiving recess 29, a projection 21 is provided, extending radially from the outer surface of the push member in the direction of the cylinder axis Z and running parallel to it on the outer surface of the push member 20. This projection prevents the push member 20 from rotating relative to the eccentric ring 18. Alternatively, the projection can also be provided as an integral part of the push member, i.e., without the receiving recess 29 and key 21.

[0050] On the left side in Figure 2B The connecting rod bearing 23 is shown for the connecting rod. Figure 2BThis illustrates that the eccentric ring is also a sleeve-shaped component that forms a circumferential ring around the thrust member 20 (relative to the axis of rotation B). A guide groove 22 is provided in the eccentric ring 18, in which the projection of the thrust member 20, in particular the key 21, runs. This prevents the thrust member 20 and the eccentric ring 18 from rotating relative to each other with respect to the axis of rotation B of the drive shaft 13. At the same time, however, the thrust member can be adjusted axially with respect to the axis of rotation B and thus displaced relative to the eccentric ring 20 in this direction. For this purpose, the corresponding guide groove is longer in axial direction B than the total extent of the projection. Due to the inclined position of the outer surface of the thrust member 20 relative to the axis of rotation B of the drive shaft, such a longitudinal movement of the thrust member 20 changes the eccentricity of the outer surface of the eccentric ring 18.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 with reference to the sectional views below. The eccentric rotational movement of the eccentric ring 18 is transmitted to the connecting rod 11, which surrounds the eccentric ring on its outer surface. The resulting eccentricity E is shown in the... Figures 4A and 4B specified 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.

[0051] Figure 3 shows the embodiment according to Figure 2A in a sectional view in a vertical plane along the axis of rotation B of the drive shaft 13 and Figure 4A the framed area from a close-up. The Figure 3 and 4aThis illustrates that, due to the design of the push member 20 and the eccentric ring 18 described above, a longitudinal movement of the push member 20 causes a radial adjustment of the eccentric ring 18 relative to the drive shaft 13. The inclined arrangement of the cylindrical surface of the push member 20 ultimately results in a sliding ramp 24 on the push member 20. The eccentric ring rests against this sliding ramp 24 with a correspondingly designed sliding guide, corresponding to its inner surface. If the relative position of the push member 20 is now adjusted along the axis of rotation B of the drive shaft 13 relative to the eccentric ring 18, the eccentric ring 18 slides along the sliding ramp 24 of the push member 20 and thus rises or falls relative to the axis of rotation B. This adjustment movement is driven by the axial adjustment device 30, which is connected to the push member 20 via the axial bearing 31. Figure 4AIt is evident that the adjustment movement of the push 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 push member 20 in the axial direction of the rotation axis B on both sides.

[0052] The Figures 4A and 4B This concerns the two extreme possible stroke settings in the present embodiment. Figures 4A and 4B Each figure shows a sectional view through the eccentric device 17, specifically when the connecting rod 11 or the eccentric device 17 has reached its top dead center. If, in the present embodiment, the thrust member 20 is shifted to the right on the drive shaft and abuts the stop 27, the distance in the horizontal plane, for example to the upper edge of the bracket 14, is ΔH1 (this large stroke corresponds to twice the vertical distance between E and B in the figure). Fig. 4aA rotational movement of the drive shaft 13 results in the eccentric ring 18 performing an eccentric rotational movement, thereby driving the connecting rod 11 and ultimately the [unclear text]. Figure 4A The tamping bar (not shown) is set into the tamping motion. The position of the eccentric ring axis E, i.e., the axis that forms the central axis of the outer circumferential surface of the eccentric ring, is shown in Figure 4A The following is also shown for further illustration. It is clearly evident that this axis runs parallel but not coaxially to the axis of rotation B of the drive shaft 13.

[0053] In the present embodiment, the push member 20 is shifted to the left on the drive shaft, as shown in the example in Figure 4BAs shown, and where it abuts the stop 26, the distance in the horizontal plane, for example to the upper edge of the bracket 14, is ΔH2. If the push member 20 is moved from right to left, the eccentric ring slides along its sliding guide on the sliding ramp of the push member 20 and approaches the rotation axis B of the drive shaft 13 with its central axis Z. This continues until the movement of the push member 20 along the drive shaft 13 is stopped by the stop 26. If the drive shaft 13 is moved in the Fig. 4B When rotated to the position shown, the eccentric ring 18 rotates around the drive shaft 13 with the reduced stroke ΔH2.

[0054] An alternative embodiment, also encompassed by the invention, consists, for example, in the following: Fig. 3The actuating element 33 shown is to be fixedly connected to the rod 34, and the rod 34 is to be moved linearly in the axial direction for axial adjustment. Instead of a rotary adjustment movement of the rod 34, in this case the rod 34 is 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.

[0055] 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 as a rack and pinion system. The corresponding drive device can be operatively connected to the rod 34 at at least one or both of its axial ends.

[0056] As can be seen from the embodiments described herein, a tamper bar device is advantageously provided which enables stroke adjustment in an improved manner. The possibility of stepless adjustment is particularly advantageous. Furthermore, a stroke adjustment is enabled in which material stresses during the adjustment process can be reduced compared to solutions known from the prior art. REFERENCE MARK LIST

[0057] 1 Road paver 2 Bunker 3 Drive motor 4 Screed 5 Travel devices 6 Operator's stand 7 Pull 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 Retaining arm 15 Center section 17 Eccentric device 18 Eccentric ring 20 Push member 201 First section of the push member 202 Second section of the push member 21 Projection / Keyway 22 Guide groove 23 Connecting rod bearing 24 Sliding ramp 26 Stop 27 Stop 29 Receiving recess 30 Axial adjustment device 31 Thrust bearing 311 First bearing 312 Second bearing 313 Third bearing 314 Contact-free area 315 Rolling bearing 32 Adjusting ring 321 Recess / annular groove 33 Actuating element 331 First end of the actuating element 332 Second end of the actuating element 333 Extensions 34 Rod 341 Central axis of the rod 35 Bushing A Working direction B Direction of travel C Stamping / lifting movement

Claims

1. A tamping beam device (8) of a paving screed (4), in particular of a road paver (1), with a tamping beam (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 configured such that a first and a second stroke setting of the tamping beam (10) can be set by means of a thrust member (20) which is axially adjustable on the drive shaft (13), characterized in that the thrust member (20) comprises a first region (201), which is arranged in the eccentric device (17), and a second region (202), which is arranged outside the eccentric device (17), the second region (202) being connected to an axial adjustment device (30) via a thrust bearing (31).

2. The tamping beam device (8) according to claim 1, wherein the thrust bearing (31) is provided between an adjusting ring (32) mounted on the second region (202) of the thrust member (20) and an actuating element (33) of the axial adjustment device (30).

3. The tamping beam device (8) according to claim 2, wherein a first end (331), in particular a head, of the actuating element (33) at least partially engages around the adjusting ring (32).

4. The tamping beam device (8) according to any 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 actuating element (33), in particular wherein the first bearing (311) and the second bearing (312) are arranged opposite each other, preferably diametrically opposite each other, and wherein a contact-free region (314) between the adjusting ring (32) and the actuating element (33) is provided in the circumferential direction between the first bearing (311) and the second bearing (312).

5. The tamping beam 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 actuating element (33).

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

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

8. The tamping beam device (8) according to any one of claims 2 to 7, wherein the actuating 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. The tamping beam device (8) according to any one of claims 2 to 4, wherein the first bearing (311) and the second bearing (312) are rolling bearings (315).

10. The tamping beam device (8) according to any one of claims 2 to 9, wherein the actuating element (33) is fixed to a rod (34) of the axial adjustment device (30), wherein the rod (34) runs essentially parallel to the drive shaft (13).

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

12. The tamping beam device (8) according to any of the preceding claims, wherein the axial adjustment device (30) has a manual or motorized drive, in particular a spindle drive, for axial adjustment.

13. A paving screed (4) for a road paver with a tamping beam device (8) according to any one of claims 1 to 12.

14. The paving screed (4) according to claim 13, characterized in that it comprises a tamping beam (10) which is supported and driven via at least two of the tamping beam devices (8) according to any one of claims 1 to 11.

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

16. A method for changing the stroke of a tamping beam device (8), in particular according to any of claims 1 to 12, comprising the steps of: a) operating the tamping beam 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 rotation axis (131) of the drive shaft (13) via an axial adjustment device (30), which is connected to the thrust member (20) via a thrust bearing (31); c) converting the movement of the thrust member (20) along the drive shaft (13) into an adjustment movement of an eccentric ring (18) in radial direction relative to the rotation axis (131) of the drive shaft (13); d) striking of the thrust member (20) against an axial stop; and e) operating the tamping beam device (8) with a second stroke setting by transmitting the rotary 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.