JP2013117161A - Device for adjusting stroke of tamping beam of road finishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for adjusting the stroke of a tamping beam of a road finishing device that enables easy stroke adjustment without interrupting operation.SOLUTION: In a device for adjusting the stroke of a tamping beam of a road finishing device, the tamping beam is vertically vibrated while oscillated, between a top dead point and a bottom dead point by means of a cam shaft with an eccentric cam and a cam rotation axis. For this purpose, the cam is formed to change its eccentricity and offset adjustment is forcibly made on the cam rotation axis according to the change in the eccentricity.

Description

  The present invention is an apparatus for adjusting the stroke of a tamping beam of a road finishing device having a rotational drive device for the tamping beam, which has a top dead center and a bottom dead center and performs an oscillating vertical motion. And an apparatus including an eccentricity adjusting device and a shaft position adjusting device for the camshaft (13) on the vibration surface.

  A tamping beam, also called a tamping device, can be placed in front of the paving screed, which solidifies the paving material by tamping vertical movement and supports the flow of material to be paved under the paving screed. For this purpose, the tamping beam is connected via a push rod to a rotary drive, during which the oscillating vertical motion specified as the amplitude or stroke of the tamping beam is created. It is. In the known tamping beam, the drive device comprises a crankshaft, for example.

  Usually, the hardening by the tamping beam of the road finishing device does not replace the subsequent hardening by the roller. This is because in the case of hardening with a tamping beam, there is also a pre-stamping story. However, in order to achieve a better pavement surface, a high degree of pre-stamping with a tamping beam is advantageous. It is also particularly efficient because it takes place at the highest possible temperature of the paving material and minimizes the risk of material sliding during subsequent rolling compaction. Furthermore, it is possible to reduce the roller compaction force.

  The known tamping beam has a flat base surface with a width of about 2 to 3 cm, and its front approach angle is about 60 degrees. The reason why such geometry is selected is that it is possible to pave all of the pavement used and the normal layer thickness without any damage to the pavement or pavement equipment. Because there is. This involves a compromise that does not have an equally advantageous effect on all layer thicknesses and materials. For example, in a tamped beam with a large layer thickness and a small base area, the material is mainly pushed forward, with only a slight compression (consolidation) in the vertical direction. In this case, it rests on the material already present below the paving screed, thereby facilitating to some extent the flow of another material below the paving screed. With a relatively large base area tamped beam, it is certainly possible to achieve increased vertical compression (consolidation) with thick layers, but with thin layers on the order of 2 cm, the material no longer flows forward. There is a risk of granular fragmentation. The vertical reaction force of the relatively wide tamping beam lifts the paving screed associated with each stroke, creating waves on the surface of the paving material.

  It is of course known to manually adjust the vibration amplitude of the tamping beam. For this purpose, however, this requires high assembly costs, since it must first allow the operator access to the adjustment device. Usually, at least a portion of the machine cladding must be removed. This means that the operation of the road finishing device has to be interrupted, which has an adverse effect on the quality of the material layer being paved.

  A general device for a tamping beam is known from DE 1459670B (Patent Document 1), in which the eccentric shaft is mounted on a rocking lever having an adjustable rocking angle. In the embodiment disclosed in EP 2325391 A1, the adjustment of the amplitude of the tamping beam is formed by a stop which is arranged with an angular offset and allows two different tamping beam amplitudes. This is done by turning an eccentric bushing that can take one position. This requires reversal of the rotational direction of the eccentric shaft. In order to adjust the size of the different strokes, the stops or the actuators engaging them can be offset by a predetermined distance in the circumferential direction. In this way, the stroke can only be adjusted in steps.

DE1459670B EP2325391A1

  The object of the present invention is therefore to provide a device of the type mentioned at the outset which allows simple stroke adjustments without interrupting the work.

  The problem is that the stroke adjustment device, the shaft position adjustment device of the cam shaft in the vibration plane, the eccentricity change is the same as that of the cam shaft in a state where only the top dead center is adjusted and the bottom dead center is maintained unchanged. This is achieved by a device comprising an eccentricity adjustment device and a forced coupling for an axial position adjustment device, configured to be compensated by a magnitude offset. Further preferred developments are described in the dependent claims.

  The invention has the advantage that when the stroke is changed, the base surface of the tamping beam at bottom dead center is maintained independently of the adjusted stroke in the surface with the base area of the pavement screed. Yes. Therefore, the width of the base surface of the tamping beam can be expanded to such an extent that the tamping beam can be sufficiently solidified even with a large layer thickness as compared with the conventional tamping beam. When a thin layer is hardened, the appropriate amplitude can be easily adjusted. Therefore, it is not necessary to align the position again after changing the amplitude. Therefore, the stroke can be changed quickly. Another advantage is that the stroke can be kept essentially small, thereby reducing wear and working noise.

  In principle, the cam and the camshaft can be adjusted by separate drive units that are controlled independently of each other. According to another preferred development of the invention, the offset of the rotational axis of the cam is effected by changing the camshaft position. According to the device, the forced offset of the camshaft is performed by coupling with the cam via a mechanical or hydraulic transmission. With this configuration, it is possible to easily convert the translation into the rotational movement required for coupling.

  When the cam is mounted to be displaceable in the radial direction on the camshaft, the camshaft is mounted on the camshaft carrier that is swingably or displaceably mounted on the base frame of the paving screed of the road finishing device, and the coupling is connected in series Especially when the linear relative motion between the camshaft carrier and the base frame on one side is converted into the relative motion between the cam and the camshaft on the other. It is advantageous.

  According to another preferred development of the invention, for the adjustment of the shaft position, two cams, each comprising an eccentric adjustment device, are mounted on the camshaft at a distance from each other, the shaft position adjustment device being Operatively connected to the cam.

  Since the two cam gears are connected via an adjustment shaft that is coaxially mounted on the cam shaft, the connection of these two cam gears is particularly simple.

  As a simple configuration, the adjustment shaft is configured as a torque-resistant spindle mounted on the cam shaft or a shaft that can be displaced in the axial direction, and each cam member is connected to a cam or a cam shaft carrier.

The invention will now be further described with reference to two embodiments shown in the drawings.
FIG. 2 is a perspective view of a first device for adjusting the stroke of a tamping beam. FIG. 2 is a partially cutaway perspective view of the apparatus of FIG. 1. FIG. 3 is a cutaway front view of the apparatus of FIGS. 1 and 2. FIG. 4 is a detailed view of a second device for adjusting the stroke of the tamping beam.

  1 and 2, the tamping beam 10 of a road finishing device (not shown) is connected to a device 12 for adjusting the stroke of the tamping beam 10 via two push rods 11. . This device 12 has a cam drive comprising a camshaft 13 fixed to a camshaft carrier 15 by means of a bearing block 14. The camshaft carrier 15 is attached to a base frame 16 of a pavement screed (not shown) known per se in a road finishing device so as to be displaceable in height. The camshaft 13 includes two eccentric cams 19 (FIG. 2), each of which cooperates with a pivot head 20 on the push rod 11. The pivot head 20 is provided with concentric bearing eyes.

  The paved screed has a slide plate 17 whose base surface 18 is substantially flat and lies on the material to be paved. The tamping beam 10 is located in front of the slide plate 17 in the traveling direction of the road finishing device. The tamping beam 10 driven by the camshaft 13 performs oscillating vertical vibration between the top dead center TO and the bottom dead center TU according to the arrow h. The cam drive creates a constant stroke of the tamping beam 10 defined by the eccentricity of the cam 19 (FIG. 2). In the schematic view of FIG. 1, the two cams of the camshaft 13 are covered by a pivot head 20 which receives one cam and one eccentricity adjusting device 21a, 21b (FIGS. 2, 3), respectively. It has been broken. At the maximum deflection of the cam, the tamping beam 10 is deflected downward to a bottom dead center TU where the lower surface of the tamping beam 10 is flat with respect to the base surface 18 of the slide plate 17. This state is illustrated in FIG.

  A step change in the stroke of the tamping beam 10 is created by a change in the eccentricity of both cams 19 (see FIG. 2). With each change in the stroke of the tamping beam 10, only the top dead center TO is adjusted upward or downward according to the arrow Δh while the bottom dead center TU remains unchanged. In this case, the bottom dead center TU is held by the forced offset of the rotational axis 33 of the cam. The offset of the rotation axis of the cam shaft is determined by the shaft position adjusting device 9 according to the arrow Δs on the base frame 16 in the same direction and in the same direction as the cam shaft carrier 15 by changing the height of the cam shaft 13. Is brought about by changing to move. Thus, the base surface 18 acts as a reference plane for adjustment of the top dead center TO or the height position of the camshaft depending on the adjusted stroke of the tamping beam 10.

  The shaft position adjusting device 9 is configured by configuring the cam shaft carrier 15 as a carriage that can be displaced on the base frame 16. It further includes a double-acting hydraulic adjustment cylinder 22 disposed in response to its action between the camshaft carrier 15 and the base frame 16. The adjusting cylinder 22 can be operated manually by an operator or via a control device, for example.

  2 and 3 further illustrate, between the shaft position adjusting device 9 and each of the two eccentric adjusting devices 21a, 21b of the same type, there is a forced coupling configured as a mechanical transmission. Is provided. This comprises a connecting rod 24, an adjusting shaft 27 and three cam gears 25, 26a, 26b. The connecting rod 24 is located between the base frame 16 and the first cam gear 25. The adjusting shaft 27 operatively connects the first cam gear 25 to two second cam gears 26a and 26b which are of the same type but act in opposite directions so that the cam gears 26a and 26b are operated in the same manner. Thereby, each of the first cam gear 25 and the two second cam gears 26a and 26b is connected in series. The adjusting shaft 27 is coaxially attached to the cam shaft 13 configured as a hollow shaft, and there is a plane 28 on which the cam 19 and the cam shaft 13 are connected to each other so as to be torque resistant, axially and radially displaceable. Have.

  The first cam gear is formed in a bushing 23, and a first pin (not shown) includes a first spiral groove 31 that engages with a connecting rod 24 that acts as a slider. The bushing 23 is rotatably mounted on the camshaft carrier 15 and functions as a bearing for the camshaft 13. The bushing 23 is mounted on the cam shaft 13 so as to be displaceable, and is connected to the radial drive tag 32 on the adjustment shaft 27 so as not to slide. The drive tag 32 is rotatably guided in an annular groove 34 inside the bushing 23, whereby the adjustment shaft 27 can be rotated together with the cam shaft 13. In FIG. 3, the cam shaft 13 includes a longitudinal hole 35 extending in the axial direction, and the drive tag 32 is guided from the adjustment shaft 27 to the bushing 23 through these holes. Each of the second cam gears 26a, 26b is composed of a second spiral groove 29 of the cam 19 and one radial second pin 30 on the adjusting screw 27 which also acts as a slider.

  When the height of the cam gear shaft 15 is adjusted by the operation of the first cam gear 25, the vertical force component applied to the connecting rod 24 of the first spiral groove 31 by the pin is converted into the horizontal force component by the oblique position of the first spiral groove 31. Therefore, the connecting rod 24 slides the bushing 23 in the axial direction on the cam shaft 13. The adjustment shaft 27 is displaced together with the bushing 23 by the drive tag 32. Instead of the drive tag 32, the adjusting screw 27 can be provided with a spindle screw, and the bushing 23 can be configured as a spindle nut.

  Due to the displacement of the adjusting screw 27, the second cam gears 26a, 26b are operated, and the second pin 30 acts on the second screw groove 29, whereby the radial displacement of the two cams 19 on the cam shaft 13 is reduced. Occurs, which corresponds to the adjustment of the eccentricity of these cams 19.

  The transmission ratio of the three cam gears 25, 26 a, and 26 b indicates that the displacement path along the arrow Δs of the cam shaft carrier 15 in the vibration direction of the tamping beam 10 corresponds to the change in stroke of the tamping beam 10 along the arrow Δh. It is selected to be exactly the same size as the 19 eccentricity changes. For this purpose, the two second cam gears 26a, 26b further decrease the eccentricity of the cam 19 when the camshaft carrier 15 is offset downward and increase when the camshaft carrier 15 is offset upward. Is configured to do. In this way, the bottom dead center TU of the tamping beam 10 is always located on the reference plane formed by the slide plate 17 or the base surface 18 of the paved screed, independent of the adjusted stroke of the tamping beam. The stroke change is compensated for the bottom dead center TU. In response to the stroke change, only the top dead center TO changes its position.

  Instead of the above-described example in which the camshaft carrier 15 drives the eccentricity adjusting device 21, the eccentricity adjusting device 21 is displaced, for example, by the operator directly or by a controller (not shown). It is also possible to adjust directly. In that case, the eccentricity adjusting device 21 drives the shaft position adjusting device 9 in reverse kinematically by the above-described forced coupling acting in the opposite direction.

  When the height of the camshaft carrier 15 is adjusted along a straight line and the cam gears 25, 26a, and 26b have a linear transmission ratio, the offset of the camshaft carrier 15, and thus the offset of the cam rotation axis, is tamped. The ratio is 1: 1 for the change in the stroke of the beam 10. For example, when the camshaft carrier is attached to a swing arm or when the camshaft is eccentrically mounted as shown in FIG. 4 to adjust the height position of the camshaft carrier 15 along the swing curve, and If the transmission ratio of the slide gear is not linear, then a corresponding adaptation must be made so that the compensation is performed as described above.

  In the shaft position adjusting device 9 ′ of the second embodiment, double eccentricity is provided in order to compensate for an amplitude change according to the arrow Δh of the cam 13. Unlike the first embodiment of FIGS. 1-3, the pivot head 20 'has an eccentric bearing eye 36' rather than a concentric bearing eye. The bearing eye 36 ′ is eccentrically attached to a disk 37 that is rotatably mounted in the bearing ring 38. The push rod 11 is fixed to the bearing ring 38. When the eccentricity of the cam 19 is adjusted according to the arrow Δh, the cam shaft 13 moves in the opposite direction according to the arrow Δs by turning the disk 37 in the bearing ring 38.

Claims (6)

An eccentricity adjusting device (21) in which the camshaft (13) having an eccentric cam (19) causes the squeezed beam (10) to oscillate vertical vibration having a top dead center and a bottom dead center (TO, TU) in the vibration plane A device for adjusting the stroke of the tamping beam (10) of the road finishing device comprising a shaft position adjusting device (9) for the camshaft (13) in the vibration plane,
A forced coupling for the eccentricity adjusting device (21) and the shaft position adjusting device (9) is provided, whereby only the top dead center (TO) is adjusted and the bottom dead center (TU) is changed. The change in eccentricity is compensated by the same amount of offset of the camshaft (13) so that
The cam (19) is attached to the cam shaft (13) so as to be radially displaceable,
The camshaft (13) is attached to a camshaft carrier (15) that is swingably or displaceably mounted on a base frame (16) of a paving screed of the road finishing device, and the coupling is thereby The linear relative motion between the camshaft carrier (15) and the base frame (16) on one side is converted into the relative motion between the cam (19) and the camshaft (13) on the other side. Consists of two cam gears (25, 26),
A device for adjusting the stroke of a tamping beam (10) of a road finishing device, characterized in that.   2. The device for adjusting the stroke of a tamping beam (10) of a road finishing device according to claim 1, wherein the coupling is configured as a mechanical or hydraulic transmission.   The road finishing device according to claim 1 or 2, wherein the two cam gears (25, 26a, 26b) are connected via an adjustment shaft (27) coaxially attached to the cam shaft (13). Device for adjusting the stroke of the tamping beam (10). The adjusting shaft (27) is configured as a spindle attached to the cam shaft (13) in a torque-resistant manner or a shaft displaceable in the axial direction,
The stroke of the tamping beam (10) of the road finishing device according to claim 3, wherein each of the cam gears (25, 26a, 26b) is connected to the cam (19) or the camshaft carrier (15). Device to adjust. Two cams (19) each having an eccentricity adjustment device (21a, 21b) are mounted on the camshaft (13) at a distance from each other,
The said shaft position adjusting device (9) adjusts the stroke of the tamping beam (10) of the road finishing device according to any one of claims 1 to 4, operatively connected to both cams (19). apparatus.   Device for adjusting the stroke of the tamping beam (10) of a road finishing device according to any one of the preceding claims, wherein the camshaft carrier (15) is mounted on a linearly displaceable carriage. .

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