Stuffing unit for stuffing under sleepers of a track

Description

field of technology

[0001] The invention relates to a tamping unit for tamping under the sleepers of a track, comprising a tamping unit with opposing tamping tools mounted on a height-adjustable tool carrier, each of which is coupled to a vibration drive via an auxiliary drive, wherein each tamping tool comprises a pivot lever rotatable about a pivot axis and at least one tamping tool holder for receiving at least one tamping pick. State of the art

[0002] To restore or maintain a specific track alignment, ballasted tracks are regularly treated with a tamping machine. The tamping machine travels along the track and raises the track bed, consisting of sleepers and rails, to a target level using a lifting / aligning unit. The new track alignment is then fixed by tamping under the sleepers 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.

[0003] Such tamping units for tamping under the sleepers of a track have been known for a long time. For example, AT 343 168 B discloses a tamping unit with a tool carrier on which a vibratory drive and two rotatably mounted tamping tools are arranged. Each tamping tool includes a swivel arm that is connected to the vibratory drive via an associated auxiliary drive. The auxiliary drives are located on opposite sides of the vibratory drive and are aligned approximately on a common axis. The overall dimension of the tamping unit in the longitudinal direction of the rail is thus approximately twice the length of an auxiliary drive and exceeds a typical sleeper spacing. Therefore, such a design is not suitable for arranging several identical tamping units within a single machine for simultaneously tamping adjacent sleepers.

[0004] A tamping unit with reduced dimensions is disclosed in Austrian patent application A 325 / 2017 (see AT 520267 A1, published on February 15, 2019). Here, adjacent auxiliary drives are supported on brackets, which in turn are connected to a common vibration drive. While this design is particularly compact, the adjacent auxiliary drives generate moments about a vertical axis during operation. These moments must be absorbed by appropriately dimensioned components. Summary of the invention

[0005] The invention is based on the objective of providing an improved design for a stuffing unit of the type mentioned above, compared to the prior art.

[0006] According to the invention, this problem is solved by the features of claim 1. Dependent claims specify advantageous embodiments of the invention.

[0007] The design provides that a first auxiliary drive is directly coupled to the vibration drive and articulated to a first pivoting lever, and that a second auxiliary drive is coupled to the vibration drive via a separate coupling unit and articulated to a rocker arm mounted on the tool carrier and to a second pivoting lever. In this way, the tamping unit can be designed very compactly with the auxiliary drives arranged one above the other, while forces and torques occurring during operation are easily controlled. The dimensions of the individual components do not result in any increase in weight compared to conventional tamping units with auxiliary drives connected directly opposite the vibration drive and pivoting arms splayed outwards. The arrangement according to the invention eliminates the need for the splayed pivoting arms, thereby compensating for the additional mass of the coupling unit.

[0008] An improvement in the kinematic conditions involves positioning the pivot axes of the two pivot levers at different heights. This measure ensures balanced leverage forces on the two tamping tools during operation by aligning the leverage ratios of the two pivot levers. Furthermore, identical stroke lengths of the auxiliary drives result in identical stroke lengths at the free ends of the tamping tools.

[0009] In an advantageous embodiment of the invention, the vibration drive comprises an eccentric shaft, wherein a ball joint of the first auxiliary drive is mounted on a first eccentric shaft section, and wherein a ball joint of the coupling unit is mounted on a second eccentric shaft section. The vibration movements transmitted from the vibration drive to the ball joints are precisely determined by the eccentricities of the eccentric shaft, independent of opposing forces. This advantage is not present in other vibration generators that produce vibration by means of imbalances or by pulsating the action of a hydraulic cylinder.

[0010] It is advantageous for the first and second eccentric wave sections to have different eccentricities. The respective eccentricity can be adapted to the kinematic arrangement of the vibration-transmitting components. This ensures that the same vibration amplitude with an approximately equal impact force acts on the gravel to be compacted at each end of the tamping pick.

[0011] In a further improvement, each auxiliary drive comprises a hydraulic cylinder with one working axis, with all working axes lying in a common plane of symmetry oriented perpendicular to the pivot axes. This ensures that all components for transmitting the auxiliary forces are loaded symmetrically and that no disruptive moments occur.

[0012] It is advantageous if the coupling unit comprises two coupling arms arranged symmetrically to the plane of symmetry, and / or if the rocker arm comprises two rocker arms arranged symmetrically to the plane of symmetry. Essentially, only tensile and compressive forces then act on the coupling unit or the rocker arm, which facilitates optimized dimensioning of the two coupling arms or rocker arms.

[0013] For a uniform transmission of vibration forces to the second tamping tool, it is advantageous if the connection between the second auxiliary drive and the coupling unit is designed as a pivot joint with a rotation axis aligned parallel to the pivot axes. In this way, the second auxiliary drive forms the coupling of a double rocker arm with optimal support of the forces prevailing during operation.

[0014] It is advantageous if the connection between the second auxiliary drive, the coupling unit, and the rocker arm is designed as a common pivot joint. This reduces the number of components and the associated wear.

[0015] Furthermore, the kinematics of the arrangement are particularly advantageous when the rocker arm is rotatably mounted about the pivot axis of the first pivot lever. This measure also leads to a reduction in the number of components by utilizing an existing pivot joint. For example, only a pivot bolt that is already provided for the additional mounting of the rocker arm is made longer.

[0016] In a further advantageous development of the tamping unit, several tool carriers are mounted in a common, height-adjustable frame. This compact design allows for the creation of a multi-sleeper tamping unit, in which several identical tamping units are arranged. The tamping units, mounted one behind the other in the common frame, can then be lowered together into a ballast bed to tamp several adjacent sleepers simultaneously. Brief description of the drawings

[0017] The invention is explained below by way of example with reference to the accompanying figures. These show, in schematic representation: Fig. 1 Side view of a tamping unit Fig. 2 Front view of the tamping unit according to Fig. 1 Fig. 3 Kinematics according to Fig. 1 Fig. 4 alternative kinematics Description of the embodiments

[0018] The in the Figures 1 and 2 The depicted tamping unit 1 comprises a unit frame 2, which is attached to a machine frame 3 of a track construction machine (not described in detail). During operation, the track construction machine travels along a track with sleepers 5 supported on a ballast bed 4 and rails 6 attached to them. The sleepers 5 are tamped successively by means of the tamping unit 1.

[0019] In the aggregate frame 2, a tool carrier 7 is guided in a height-adjustable manner, with a lowering or raising movement being effected by means of an associated height adjustment drive 8. A vibration drive 9 is arranged on the tool carrier 7, to which at least one first auxiliary drive 10 and a separate coupling unit 11 for a second auxiliary drive 12 are connected. In addition, at least one first tamping tool 13 and one second tamping tool 14 are rotatably mounted on the tool carrier 7 about a respective pivot axis 15. Each tamping tool 13, 14 comprises a pivot lever 16, 17 and a tamping tool holder 18 for receiving at least one tamping pick 19.

[0020] For example, an eccentric drive with a rotating eccentric shaft is used as the vibration drive 9, wherein an associated eccentricity e1, e2 defines a vibration amplitude for each tamping tool 13, 14 and can be adjusted. A rotational speed determines the vibration frequency. The respective auxiliary drive 10, 12 is designed as a hydraulic drive with a hydraulic cylinder and a control valve. The respective working axis 20 of the hydraulic cylinders advantageously lies in a common plane of symmetry 21 oriented perpendicular to the pivot axes 15.

[0021] To transmit a vibration movement 22 and an adjustment movement 23 to the first tamping tool 13, the first adjustment drive 13 is directly coupled to the vibration drive 9 and pivotally connected to the pivot lever 16 of the first tamping tool 13 via a rotary joint 24. In the exemplary embodiment, a pivot eye of the hydraulic cylinder is mounted on a first eccentric section of the eccentric shaft. In this way, the entire first adjustment drive 13 oscillates when the eccentric shaft rotates. The adjustment movement 23 is superimposed on this vibration movement 22 by applying force to the first adjustment drive 13.

[0022] In the second tamping tool 14, the motion transmission occurs differently. Here, the second auxiliary drive 12 is coupled to the vibration drive 9 via the separate coupling unit 11 and supported by a rocker arm 25 mounted on the tool carrier 7. In the exemplary embodiment, the connection between the coupling unit 11 and the second auxiliary drive 12 is designed as a pivot joint 24. The coupling unit 11 is mounted with a ball joint on a second eccentric section of the eccentric shaft. The coupling unit acts as a connecting rod to convert the circular motion of the eccentric shaft into an oscillating motion of the second auxiliary drive 12. Fig. 3 The kinematics of this arrangement are shown. For better illustration, the eccentricities e1 and e2 are shown enlarged. The fixed bearings 26 indicate the bearing positions of the components on the tool carrier 7.

[0023] In Fig. 4Another embodiment is shown. Here, the coupling unit 11 is rigidly connected to the second auxiliary drive 12 and mounted on the second eccentric section of the eccentric shaft by means of a cam-like guide 27. In this way, only movements in the direction of the effective axis are transmitted from the eccentric shaft to the coupling unit 11 and thus to the second auxiliary drive 12.

[0024] The eccentricities e1, e2 of the first and second eccentric shaft sections are preferably arranged offset by approximately 180° to achieve mass balance during vibration generation. Furthermore, it is advantageous to design the two eccentricities e1, e2 differently. The respective eccentricity e1, e2 is then optimally adapted to the kinematic arrangement of the associated tamping tool 13, 14, so that all tamping pick ends always exhibit the same vibration amplitude during operation.

[0025] For symmetrical force transmission to the second pivot lever 17, the coupling unit 11 and the rocker arm 25 29 each have two arms arranged symmetrically to the plane of symmetry 21. Each coupling arm has a ball joint. The second eccentric section of the eccentric shaft is divided into two parts, with the two ball joints of the coupling unit 11 mounted on either side of the ball joint of the first auxiliary drive 10. In this way, no moments about a vertical axis act on the eccentric shaft during operation.

[0026] The new arrangement of the motion-transmitting elements enables a very compact design for the tamping unit 1. The auxiliary drives 10, 12 are arranged one above the other, so that the overall dimension of the tamping unit 1 in the longitudinal direction of the rail only slightly exceeds the length of one auxiliary drive 10, 12. Furthermore, the vibration drive 9 is not arranged symmetrically between the two tamping tools 13, 14, as is the case with conventional tamping units. The present arrangement of the vibration drive 9 above the second tamping tool 14 creates space for a central arrangement of the height adjustment drive 8. The resulting central force application during the lowering and raising of the tool carrier 7 protects the longitudinal guides 28 on the unit frame 2, because no moments about a transverse axis occur.

[0027] In a tamping unit 1 for tamping under a sleeper 5, four tamping units 29 are usually arranged side by side, with one tamping unit 29 being used on each side of a rail 6. The compact design of this unit also allows several identical tamping units 29 to be arranged one behind the other in a single unit frame 2. Each tamping unit 29 is guided separately on longitudinal guides 28 and can be lowered or raised by means of its own height adjustment drive 8. In this way, several adjacent sleepers 5 can be tamped simultaneously in a single operation.

Claims

1. A tamping assembly (1) for tamping sleepers (5) of a track, including a tamping unit (29) having oppositely positioned tamping tools (13, 14) mounted on a vertically adjustable tool carrier (7), the tamping tools (13, 14) being coupled in each case via a squeezing drive (10, 12) to a vibration drive (9), wherein each tamping tool (13, 14) comprises a pivot lever (16, 17) rotatable about a pivot axis (15) and at least one tamping tool mount (18) for accommodating at least one tamping tine (19), characterized in that a first squeezing drive (10) is coupled directly to the vibration drive (9) and articulatedly connected to a first pivot lever (16), that a second squeezing drive (12) is coupled to the vibration drive (9) via a separate coupling unit (11) and articulatedly connected to a link (25), mounted on the tool carrier (7), as well as to a second pivot lever (17).

2. A tamping assembly (1) according to claim 1, characterized in that the pivot axes (15) of the two pivot levers (16, 17) are arranged at different heights.

3. A tamping assembly (1) according to claim 1 or 2, characterized in that the vibration drive (9) includes an eccentric shaft, that an articulated lug of the first squeezing drive (10) is mounted on a first eccentric shaft section, and that an articulated lug of the coupling unit (11) is mounted on a second eccentric shaft section.

4. A tamping assembly (1) according to claim 3, characterized in that the first eccentric shaft section and the second eccentric shaft section have different eccentricities (e1, e2).

5. A tamping assembly (1) according to one of claims 1 to 4, characterized in that each squeezing drive (10, 12) comprises a hydraulic cylinder having an effective axis (20), and that all effective axes (20) lie in a common plane of symmetry (21) extending perpendicularly to the pivot axes (15).

6. A tamping assembly (1) according to claim 5, characterized in that the coupling unit (11) has two coupling arms which are arranged symmetrically to the plane of symmetry (21), and / or that the link (25) has two link arms which are arranged symmetrically to the plane of symmetry (21).

7. A tamping assembly (1) according to one of claims 1 to 6, characterized in that a connection of the second squeezing drive (12) to the coupling unit (11) is designed as a swivel joint (24) having a rotation axis extending parallel to the pivot axes (15).

8. A tamping assembly (1) according to claim 7, characterized in that the connection of the second squeezing drive (12) to the coupling unit (11) and to the link (25) is designed as a common swivel joint (24).

9. A tamping assembly (1) according to one of claims 1 to 8, characterized in that the link (25) is mounted for rotation about the pivot axis (15) of the first pivot lever (16).

10. A tamping assembly (1) according to one of claims 1 to 9, characterized in that several tool carriers (7) are mounted for vertical adjustment in a common assembly frame (2).