tamping unit for tamping a track

Description

field of technology

[0001] The invention relates to a tamping unit for compacting ballast in a track bed by means of a tamping unit comprising several tamping tools, wherein each tamping tool is assigned a drive mechanism to move the tamping tool ends approximately in the direction of a rail / sleeper intersection during a tamping process, wherein each tamping tool end has at least one tamping plate which can be moved at least partially into an area below the rail by means of the assigned drive mechanism, wherein a control device of the respective drive mechanism is provided to control a corresponding movement, and wherein each tamping tool has a pivotable end which can be pivoted about a pivot axis by means of an auxiliary cylinder.

[0002] Includes swivel lever. State of the art

[0003] To restore or maintain a specific track alignment, ballasted tracks are regularly treated using a tamping machine. The tamping machine travels along the track and, using a lifting / aligning unit, raises the track bed, consisting of sleepers and rails, to a predetermined position. The new track alignment is then fixed by tamping the track with a tamping unit. This unit comprises tamping tools with tamping picks, which, during the tamping process, vibrate and penetrate the ballast bed, aligning themselves with each other. This compacts the ballast beneath each sleeper.

[0004] When tamping with a tamping unit known from AT 343 168 B or AT 516 547 A4, each rail of the track is assigned two pairs of tamping tools. An inner pair of tamping tools enters the ballast bed next to the inside of a rail, and an outer pair of tamping tools enters it next to the outside of a rail. The positioning movement of each tamping tool occurs at a right angle to the longitudinal dimension of the sleeper at the respective point of entry. Consequently, the greatest compaction effect on the ballast occurs in a primary compaction zone between the entry points of the tamping tools of a tamping tool pair. These are the areas next to the rails. Secondary ballast compaction occurs under the rails and in the end areas of the sleepers due to the ballast displaced from the primary compaction zone.

[0005] From DE 25 16 166 A1, a tamping unit with inclined tamping tools is known. In this unit, each tamping tool makes an adjustment movement approximately in the direction of the rail / sleeper intersection point to create a primary compaction zone directly beneath the respective rail. However, in such a method, each tamping tool requires its own vibrator. Furthermore, additional tamping tools are necessary to prevent the ballast from shifting upwards and into areas between the tamping tools.

[0006] AT 315 891 B discloses a tamping unit in which each tamping tool is arranged on a main beam, the main beam being pivotably mounted on a height-adjustable slide by means of a swivel cylinder. This allows the tamping tools, together with their associated auxiliary cylinders and the main beam, to be pivoted in the direction of a rail. Summary of the invention

[0007] The invention is based on the objective of improving a tamping unit of the type mentioned above in such a way that an optimally compacted sleeper support can be produced in a simple manner below a rail / sleeper intersection point.

[0008] According to the invention, this problem is solved by the features of claim 1. Dependent claims specify advantageous embodiments of the invention.

[0009] The tamping unit according to the invention ensures that the sleeper supports below the respective rail / sleeper intersection are optimally compacted. The highest forces act on the track at the rail / sleeper intersections during railway operation. Insufficient compaction below the rails would lead to sleeper deflection and a progressive deterioration of the track geometry. The result of the dynamic railway traffic loads and the associated vibrations would be an inhomogeneous ballast bed with irregular track settlement.

[0010] The design incorporates pick plates positioned at the ends of the tamping tool, which are moved at least partially into an area below the rail during the tamping process. This ensures that the pick plates on each side of the sleeper are brought very close together. The pick plates thus act collectively on the area below the rails, creating optimal sleeper support without ballast shifting upwards or between the pick plates. Compared to conventional methods, this reduces the stress on the sleepers, resulting in a longer track lifespan. Furthermore, the centric ballast compaction below the rails provides greater lateral resistance to movement of the respective sleeper, thereby improving the track's load-bearing capacity.

[0011] The design of the tamping unit is characterized by the fact that each tamping tool comprises a pivoting lever that can be rotated around a pivot axis and a tamping tool holder for receiving at least one tamping pick. This provides a simple and effective kinematic system for transmitting the vibration and tamping motion from the drives to the tamping picks penetrating the ballast. The tamping force can also be effectively transmitted from the respective drive unit to the corresponding pick plate(s).

[0012] According to the invention, each tamping tool is equipped with a drive cylinder for moving the tamping tools towards the sleeper and a separate pivoting cylinder for moving the tamping tools towards the rail. Specifically, each tamping tool, designed to hold at least one tamping pick, includes a tamping pick holder that can be pivoted relative to the associated pivot lever in the direction of the rail by means of a pivoting cylinder. This allows the respective tamping tool to be pivoted towards the rail before the actual tamping movement. The respective pick plates are then positioned below the rail throughout the entire tamping process and continuously act on the ballast in the area of ​​the rail / sleeper intersection.

[0013] In a further development of the tamping unit, each tamping tool is mounted on an assigned tool carrier, the height of which is adjustable by means of a height adjustment drive. The tool carrier is guided vertically, for example, within a unit frame and is lowered and raised again together with the tamping tools during a tamping cycle.

[0014] An improvement to this design involves controlling the height adjustment drive via the control unit and providing the control unit with a signal from a sensor to detect the height position. This ensures that the tamping tools are only moved towards the rail after sufficient lowering has occurred. This prevents the rail from colliding with the tamping plates.

[0015] In this method, a depth limit is specified for a lowering operation, whereby the tamping tool ends are only moved towards the rail once this depth limit is reached. This ensures that the tamping tool ends only move towards each other below the rail after a predetermined immersion depth. At least one tamping plate surface should be lowered below the bottom edge of a rail foot to reliably prevent contact between the tamping tool and the rail.

[0016] It is advantageous for the tamping tool ends to be moved first towards the rail and then towards the sleeper. This ensures the tamping plates are already in an optimal position before the actual tamping process begins. Furthermore, this method allows for tamping parallel to the rail's longitudinal axis. A suitable kinematic arrangement for moving the tamping tools is easily implemented.

[0017] A further improvement to the design is achieved when each pair of tamping tools is mounted on a common tool carrier and each tool carrier has its own height adjustment drive. This variant is suitable for a so-called universal tamping machine, which is designed for tamping track sections and turnouts. This design allows for the separate lowering or lateral movement of individual tamping tool pairs to avoid diverging rails or obstacles.

[0018] It is advantageous if each pair of tamping tools is assigned a vibration generator and two auxiliary cylinders coupled to the vibration generator. This increases the efficiency of the tamping unit because, during operation, a single vibration generator sets both tamping tools in motion. Furthermore, when the two tamping tools are subjected to vibration with opposing directions of movement, sufficient mass balance is achieved to prevent disruptive vibration loads on the unit.

[0019] Advantageously, the vibration generator includes an eccentric shaft to which the auxiliary cylinders are articulated. Such an eccentric drive provides a precisely predefined vibration amplitude and frequency, with these parameters being independent of counterforces exerted by the ballast on the tamping tools.

[0020] Another advantageous variant involves mounting each tamping tool at an angle to its associated tool carrier with respect to a vertical longitudinal plane. This ensures that, during an adjustment movement, the tamping tool ends move approximately towards the rail / sleeper intersection. This movement design results in the formation of an optimal primary compaction zone. The compaction effect of the adjusted tamping tool ends is enhanced because lateral movement of the vibrating ballast is minimized.

[0021] It is advantageous if each tamping tool is assigned a hydraulic cylinder unit as its drive mechanism, enabling the tamping tool to be set into vibration and moved approximately in the direction of the rail / sleeper intersection. A hydraulic cylinder unit can consist, for example, of several coupled hydraulic cylinders with different chambers for generating the vibration and the tamping motion. In a simpler version, both movements are performed by a single hydraulic cylinder with two chambers. In this solution, one chamber is supplied with a pulsating, increasing flow rate to superimpose the tamping and vibration movements.

[0022] A further improvement to the tamping unit involves mounting each tamping tool on its associated tool carrier so that it can be adjusted around a vertical axis of rotation. This makes it possible to tamp a track in several successive tamping operations with different angles of inclination of the tamping tools. In this process, the respective tamping tool is pivoted around its vertical axis relative to its associated tool carrier. This occurs either before it enters the ballast or during a subsequent adjustment. This allows the extent of the primary compaction zone to be adapted to changing sleeper and rail dimensions as well as to varying local conditions.For example, when laying new track with almost uncompacted ballast, it can be advantageous to widen the primary compaction zone by aligning the tamping tools opposite the sleepers in a first tamping pass. In a second tamping pass, a centered under-tamping is then achieved in the areas below the rails by tilting the tamping tools significantly. Brief description of the drawings

[0023] The invention is explained below by way of example with reference to the accompanying figures. These show, in schematic representation: Fig. 1 Cross-section through a track with tamping unit in lowered position. Fig. 2 Top view of a track with inclined positioning of the tamping plates. Fig. 3 Top view of a track with pivoting movement of the tamping plates. Fig. 4 Top view according to Fig. 3 with lateral movement of the tamping plates Fig. 5 Tamping unit in a side view Fig. 6 Top view of a track with lateral movement of inclined tamping plates according to Fig. 5 Fig. 7 Top view of a tamping unit with variable inclination of the tamping tools Description of the embodiments

[0024] The in Fig. 1 The depicted tamping unit 1 comprises four tamping units 2, with two tamping units 2 assigned to each rail 3. Each tamping unit 2 includes an assembly frame 4 in which a tool carrier 5 is guided vertically. A pair of tamping tools 6 is mounted on each tool carrier 5. In a simplified version, each rail is assigned only one tamping unit 2 with a common tool carrier 5 for four tamping tools 6.

[0025] The respective aggregate frame 4 is attached to a machine frame of a track construction machine. During operation, the track construction machine travels along a track 7 with sleepers 9 supported on ballast 8 and rails 3 fastened to them. At a distance of half a track gauge, the so-called track axis 9 runs between the rails 3, which usually serves as a reference point in railway construction work. The tamping unit 1 tamps the sleepers 9 one after the other to fix the track grid, formed by sleepers 9 and rails 3, in a predetermined position.

[0026] A lowering or raising movement of the respective tool carrier 5 is effected by means of an associated height adjustment drive 10. In the variant according to Fig. 1 A vibration generator 12 is arranged on each tool carrier 5, which imparts a vibration 13 to the tamping tools 6. In addition, motion drives 14 are assigned to the tamping tools 6, by means of which ordering or pivoting movements 15 of the tamping tool ends 16 can be carried out.

[0027] In the exemplary embodiment, each tamping tool 6 is rotatably mounted on the associated tool carrier 4 about a pivot axis 17 and coupled to the associated vibration generator 12 via an auxiliary cylinder 18. Each tamping tool 6 comprises a pivot lever 19 and a tamping pick holder 20 for receiving two tamping picks 21. The respective tamping pick holder 20 can be pivoted relative to the associated pivot lever 19 in the direction of the associated rail 3 by means of a pivoting cylinder 22. Thus, the motion drive 14 associated with a tamping tool 6 comprises an auxiliary cylinder 18 and a pivoting cylinder 22 together with corresponding control valves.

[0028] The tamping picks 21 located at the ends 16 of the tamping tool each have a pick plate 23 which acts on the ballast 8 during operation. Specifically, a primary compaction zone 24, shown with cross-hatching, is formed in which the ballast 7 is moved directly by the pick plates 23 approximately in the direction of a rail / sleeper intersection 25 until optimal compaction is achieved. The vibration action promotes the mobility of the individual ballast grains within the ballast structure.

[0029] For example, an eccentric drive with a rotating eccentric shaft is used as the vibration generator 12. The eccentricity determines the vibration amplitude for the vibration 13 transmitted to the tamping tools 6. The rotational speed determines the frequency. The adjusting or pivoting movement 15 is superimposed on the vibration 13 by means of the adjusting cylinders 18 and the pivoting cylinders 22, which are mounted on the eccentric shaft.

[0030] According to the invention, the respective drive mechanism 14 is controlled by a control device 26 such that the pick plates 23 are moved at least partially into an area 27 below the associated rail 3 during an ordering or pivoting process. In this way, the primary compaction zone 24 with optimal compaction of the ballast 8 is formed below the rail / sleeper intersection 25.

[0031] Before the motion drives 14 are activated, the tool carriers 5 are lowered, causing the tamping picks 21 with the pick plates 23 to enter the ballast 8. It is important to ensure that the upper surface of each pick plate is lowered at least to below the bottom edge of a rail foot before the corresponding tamping pick 21 is moved towards the associated rail 3. For example, a depth limit is set for the respective height adjustment drive 11. Only when this depth limit is reached is the motion drives 14 enabled. An improved version includes a sensor that detects the respective height position of the tamping tools 6 relative to the associated rail foot.

[0032] Furthermore, it must be ensured that the tamping tools 6 do not collide with a sleeper 9 or a rail 3 during a return movement. A combined return and lifting movement of the tamping tools 6 is advantageous, particularly with the vibration generator 12 switched off.

[0033] A simple version of the procedure is described with reference to Fig. 2 explained. The pick plates 23, in their lowered state, are moved towards the associated rail / sleeper intersection point 25 by a combined control of the assisting and pivoting cylinders 18, 22. During this movement, a portion of the pick plates 23 closest to the rail enters the area 27 below the associated rail 3. As in Fig. 1 The starting positions of the darning picks 21 and pick plates 23 are shown with dashed lines. The end positions are shown with solid lines. Arrows indicate the corresponding direction of movement.

[0034] Another variant is shown by the Figuren 3 und 4 . In this process, the pick plates 23 are first moved in the lowered state in the direction of the associated rail 3 by means of the pivoting cylinders 22 ( Fig. 3 In this way, the pick plates 23 located on one side of the sleeper are already aligned with small gaps before the actual setting process. During the subsequent activation of the setting cylinders 18, a uniform primary compaction zone 24 builds up around the respective rail / sleeper intersection 25 throughout the entire setting process ( Fig. 4 ).

[0035] Fig. 5 Figure 1 shows a tamping unit 1 with tamping tools 6 inclined relative to a vertical longitudinal plane 28. Fig. 6 The processing of a track curve with such a tamping unit 1 is evident. In operation, the vertical longitudinal plane 28 usually runs perpendicular to the longitudinal extent of the tamped sleeper 9. It is thus tangentially aligned to the track axis 10.

[0036] In the exemplary embodiment, the tamping tools 6 are inclined at a 25° angle to the vertical longitudinal plane 28. A smaller angle, for example 5°, is suitable for the initial tamping of a newly laid track to increase the lateral effect perpendicular to the track axis 10. Larger angles up to 40° result in a pronounced centering of the primary compaction effect below the respective rail / sleeper intersection 25.

[0037] In this variant, a hydraulic cylinder unit 29 with coupled hydraulic cylinders forms the respective motion drive 14 of a tamping tool 6. Each hydraulic cylinder unit 29 generates the vibration 13 and the assisting movement 15 specifically for the assigned tamping tool 6. For example, an inner hydraulic cylinder generates the assisting movement 15 and is coupled to a piston for an outer hydraulic cylinder to provide the vibration 13. In a simplified design, each tamping tool 6 is assigned only one hydraulic cylinder. During an assisting operation, this cylinder is supplied with a pulsating, increasing flow rate to superimpose the assisting movement 15 onto the vibration 13.

[0038] In this embodiment, each stuffing tool 6 can be manufactured as an identical unit. As in Fig. 7This illustrates an arrangement of the tamping tools 6 on the associated tool carrier 5 that can be pivoted about a respective vertical axis of rotation 30 (shown as a point in the top view). In this way, the tilt angle can be adjusted. By using remote-controlled swivel drives, adjustment is also possible during operation. The tamping picks and pick plates are shown with dashed lines.

[0039] The pivotability around the vertical axis of rotation 30 is advantageous for the flexible use of the tamping unit 1. This allows for easy adaptation to different sleeper and rail widths. Furthermore, the size and shape of the primary compaction zone 24 can be quickly adjusted to existing requirements.

Claims

1. A tamping assembly (1) for consolidating ballast (8) in a track bed comprising several tamping tools (6), wherein a motion drive (14, 18, 22, 29) is associated with each tamping tool (6) in order to move the tamping tool ends (16) approximately in the direction of a rail / sleeper crossing point (25) during a tamping operation, wherein each tamping tool end (16) has at least one tine plate (23) which is movable at least partly into a region (27) underneath the rail (3) by means of the associated motion drive (14, 18, 22, 29), wherein a control device (26) of the respective motion drive (14, 18, 22, 29) is designed for controlling a corresponding motion and wherein each tamping tool (6) comprises a pivot lever (19) which is pivotable about a pivot axis (17) by means of a squeezing cylinder (18), characterized in that each tamping tool (6) comprises a tamping tine mount (20) for receiving a tamping tine (21) wherein the tamping tine mount (20) is pivotable relative to the associated pivot lever (19) in the direction of the associated rail (3) by means of a pivoting cylinder (22).

2. A tamping assembly (1) according to claim 1, characterized in that each tamping tool (6) is mounted on an associated tool carrier (5) which is vertically adjustable by means of a vertical adjustment drive (11).

3. A tamping assembly (1) according to claim 2, characterized in that the vertical adjustment drive (11) is actuated by means of the control device (26), and that a signal of a sensor for recording a vertical position is supplied to the control device (26).

4. A tamping assembly (1) according to one of claims 1 to 3, characterized in that a tamping tool pair is mounted in each case on a common tool carrier (5), and that a separate vertical adjustment drive (11) is associated with each tool carrier (5).

5. A tamping assembly (1) according to one of claims 1 to 4, characterized in that a vibration generator (12) and two squeezing cylinders (18) coupled to the vibration generator (12) are associated in each case with a tamping tool pair.

6. A tamping assembly (1) according to claim 5, characterized in that the vibration generator (12) includes an eccentric shaft to which the squeezing cylinders are articulatedly connected.