Patent ID: 12188184

DESCRIPTION OF THE EMBODIMENTS

The tamping assembly1shown inFIGS.1and2comprises an assembly frame2which is fastened to a machine frame3of a track maintenance machine not further shown. During working operations, the track maintenance machine travels on a track having sleepers5supported on a ballast bed4and rails6fastened on the former. During this, the sleepers5are tamped in sequence by means of the tamping assembly1.

A tool carrier7is guided for vertical adjustment in the assembly frame2, wherein a lowering- or lifting motion takes place by means of an associated vertical adjustment drive8. Arranged on the tool carrier7is a vibration drive9to which at least one first squeezing drive10and a separate coupling unit11for a second squeezing drive12are connected. Mounted additionally on the tool carrier7are at least a first tamping tool13and a second tamping tool14which are rotatable about a respective pivot axis15. In this, each tamping tool13,14comprises a pivot lever16,17and a tamping tool mount18for accommodating at least one tamping tine19.

Used as a vibration drive9, for example, is an eccentric drive having a rotating eccentric shaft, wherein, for each tamping tool13,14, an associated eccentricity e1, e2predefines a vibration amplitude and may be adjustable. A speed of rotation defines the vibration frequency. The respective squeezing drive10,12is designed as a hydraulic drive with a hydraulic cylinder and a control- or regulating valve. In this, the respective effective axis20of the hydraulic cylinders lies advantageously in a common plane of symmetry21extending perpendicularly to the pivot axes15.

For transmission of a vibratory motion22and a squeezing motion23to the first tamping tool13, the first squeezing drive13is coupled directly to the vibration drive9and articulatedly connected by a swivel joint24to the pivot lever16of the first tamping tool13. In the example of embodiment, an articulated lug of the hydraulic cylinder is mounted on a first eccentric section of the eccentric shaft. In this way, the entire first squeezing drive13vibrates when the eccentric shaft rotates. This vibratory motion22is superimposed by the squeezing motion23as a result of actuation of the first squeezing drive13.

At the second tamping tool14, the transmission of motion takes place in a different manner. Here, the second squeezing drive12is coupled to the vibration drive9via the separate coupling unit11and supported by a link25mounted on the tool carrier7. In the example of embodiment, the connection between the coupling unit11and the second squeezing drive12is configured as a swivel joint24. In this, the coupling unit11is mounted with an articulated lug on a second eccentric section of the eccentric shaft. The coupling unit11functions here as a connecting rod for transforming the circular motion of the eccentric shaft into a pendulum motion of the second squeezing drive12.FIG.3shows the kinematics of this arrangement. For better clarity, the eccentricities e1, e2are shown enlarged. Fixed bearings26shown in the drawings indicate the support points of the components on the tool carrier7.

A different embodiment is shown inFIG.4. Here, the coupling unit11is rigidly connected to the second squeezing drive12and mounted on the second eccentric section of the eccentric shaft by means of a slot-like guide27. In this manner, only motions in the direction of the effective axis are transmitted from the eccentric shaft to the coupling unit11and thus to the second squeezing drive12.

The eccentricities e1, e2of the first eccentric shaft section and of the second eccentric shaft section are preferably arranged offset by about 180° in order to achieve a mass compensation during the generation of vibration. Additionally, it is favourable to design the two eccentricities e1, e2differently. The respective eccentricity e1, e2is then optimally matched to the kinematic arrangement of the associated tamping tool13,14, so that all tamping tine ends always have the same vibration amplitude in operation.

For symmetrical force transmission to the second pivot lever17, the coupling unit11and the link23each have two arms which are arranged symmetrically to the plane of symmetry21. In this, each coupling arm has an articulated lug. The second eccentric section of the eccentric shaft is of two-part design, wherein the two articulated lugs of the coupling unit11are mounted on either side of the articulated lug of the first squeezing drive10. In this manner, no momentums about a vertical axis are acting on the eccentric shaft during operation.

As a result of the new arrangement of the motion-transmitting elements, a very compact design of the tamping assembly1is possible. The squeezing drives10,12are arranged one below the other, so that the overall size of the tamping assembly1in the longitudinal direction of the rails is only slightly larger than the length of a squeezing drive10,12. In addition, the vibration drive9is not arranged symmetrically between the two tamping tools13,14, as is the case with conventional tamping assemblies. The present arrangement of the vibration drive9above the second tamping tool14creates space for a centred arrangement of the vertical adjustment drive8. As a result of the centred force application during lowering and lifting of the tool carrier7thus achieved, longitudinal guides28on the assembly frame2are conserved since there are no momentums about a transverse axis.

In a tamping assembly1for tamping a sleeper5, usually four tamping units29are arranged side-by-side, wherein at either side of a rail6a respective tamping unit29is employed. The present compact design enables also the arrangement of several structurally identical tamping units29one behind the other in an assembly frame2. In this, each tamping unit29is guided separately on longitudinal guides28and can be lowered or lifted by means of a separate vertical adjustment drive8. In this way, several adjacent sleepers5can be tamped simultaneously in one working pass.