Tamping machine for compacting the ballast bed of a track

#The invention relates to a tamping machine for compacting the ballast bed of a track, comprising at least two respective tamping units for each side of the tamping machine for tamping the track, which units can each be displaced transversely relative to the longitudinal direction of the tamping machine by means of a transverse displacement device, and comprising a lifting and lining device for levelling and lining the track and optionally the diverging track of a switch, said lifting and lining device being arranged between on-track undercarriages in the working direction preferably before the tamping units.

#Tamping machines are machines which correct the track position of switches and/or tracks. Measurement systems are used for this purpose which compare the actual position of the track height, the actual position of the track direction and the actual position of the superelevation of the track during the work and which compare said values with predetermined target values. The track grid is lifted and laterally aligned by means of a lifting and lining device for such a time until the difference between the predetermined target position and the actual position is zero. This geometric position is fixed by compacting the ballast beneath the sleepers to the left and the right of the tracks by means of a tamping unit. The lifting and lining of the track grid occurs via respective hydraulic lifting and lining cylinders with proportional or servo control. Switches comprise a continuous track and a diverging track as a special feature. A change in the direction of movement of the train is produced via the so-called switch blades. The crossing region between the continuous track and the diverging track is known as the cross frog. Switch tamping machines with divided tamping units, i.e. split-head tamping units, are especially provided for tamping switches. During the tamping of a switch, the respective outer unit of one side can be pivoted upwardly in the direction of the diverging set of tracks for tamping the same.

#EP 0 386 398 B1 illustrates an embodiment of a transverse displacement device for tamping units on a sliding guide which is common to the tamping units and which is characterized by a limited transverse displacement path within the machine frame. The common transverse guide in a plane parallel to the track plane is characterized by low flexural rigidity because the guides are disposed horizontally to the track plane. The rotary device is formed by four guide rollers which are twistable about vertical axes, wherein the centring occurs via a guide surface of the machine frame which is formed in the manner of a circular segment. EP 1 845 616 B1 shows an embodiment of the transverse displacement device, which illustrates four units which are transversely displaceable on a further rotatable intermediate frame, which on its part comprises an additional transverse displacement so that a greater transverse displacement path can be achieved at least for the respectively outer unit. The path of displacement of the respectively inner units remains limited. The vertically limited flexural rigidity of the units thus guided in this manner leads to an oscillating behaviour during tamping as a result of the immersing forces, which leads to an increased permanent bending stress fatigue limit. The rotary apparatuses designed up until now are complex in their configuration and require an increased amount of maintenance. The limitation of the transverse displacement path of the inner unit of one side and the limited displacement paths in general prevent the tamping of a switch (main track and diverging track) in one operation. The prior art requires two operations for tamping a switch. Tracks that are tamped properly need to be tamped to the left and the right of the track. The main track is therefore tamped in the first operation and only the inner region of the outer track of the switch is tamped in the diverging track of the switch. Such regions are tamped in a second operation which could not be processed in the first operation. Embodiments are also known in which the outer unit part is situated on an outwardly pivotable support. In order to ensure that the unit position can be adjusted to the obliquely disposed longitudinal sleepers in the switch, it is necessary that the said support arm needs to be implemented in a longitudinally displaceable manner. The unit which is situated on the support arm must further be formed in a rotatable manner on said support arm. Such embodiments are mechanically complex and lead to vibrations of the unit during immersion and tamping.

#The subject matter of the invention is schematically shown in the drawings, wherein:

#FIG. 1 shows a track-driveable tamping machine with a rotary and a transverse displacement device of the units, the tamping units per se and the lifting and lining device in a side view;

#FIG. 2 shows the tamping units in accordance with the invention with rotary and transverse displacement devices in a front view;

#A tamping machine 22 (FIG. 1) with main supports 12 comprises tamping units 41 with a transverse displacement device 1, a lifting and lining unit 26 and a track lifting drive 25 as well as a track lining drive 33. Reference numeral 31 shows the conventional diesel engine which is used as a power source. 23 and 24 show the driver's cabins, 29 the operator's cabin. The machine 22 travels via the undercarriages 28 on the tracks 30, which are fastened on their part to the sleepers 31 to be tamped. The sleepers 31 are tamped by the tamping tines 8, which enter the ballast during the operation. The direction of work is indicated by reference numeral 32. The actual position of the track is recorded by the measuring carriage 27 and a measuring device, and the track is lifted, lined and fixed in this position by tamping by comparison with the track target position of the track. The tamping units are set up in their position in parallel to the longitudinal sleepers disposed obliquely in the switch by means of the rotary apparatus 14.

#A live ring 14 is fastened to the crossbeams 13 attached to the lateral main supports 12 (see FIG. 2) of the tamping machine 22. The entire transverse guide device can be rotated by means of said live ring 14 about the upright axis (by at least 20°) by means of the rotary drive 35. A transverse guide receiver 34 is mounted on the bottom side of the live ring 14. The motion bars or sliding tubes 2 and 3 move in a sliding manner in the transverse guide receiver 34. The motion bars or sliding tubes 2, 3 are rigidly connected to the respective outer unit 37. The inner units 38 move freely within the region 36 on the motion bars or sliding tubes 2, 3, only limited by the respective outer unit 37 and the limit stop on the inside of the transverse guide receiver 34. The units 37, 38 are transversely displaced by the transverse drives 21. Guide rods 4 for the vertical guidance of the unit boxes 5 are provided in the unit frames 1. The units 37, 38 are lifted and lowered by vertical drives 9. The working tools, which are the so-called tines 8, can be pivoted upwardly and downwardly 12. As a result of the transverse displacement, the inner unit of the right side can tamp the inner side to the left of the rail 18 first and subsequently also tamp the outer side, situated adjacent to the rail 19, by transverse displacement 17 to the outside. It is possible to proceed similarly with the outer unit concerning the tamping of the outer rail 20 of the diverging track by transverse displacement about 39. As a result, a switch position can be tamped in its entirety without displacing the tamping machine 22.

#FIG. 3 schematically shows the outer unit frame 1 with the tamping unit 41 in a side view. The tamping arms 11 are twisted about the point 10 via the adjusting cylinders 6 and the ballast is compacted in this process. The working tools, i.e. the so-called tamping tines 8, can be laterally pivoted via the tamping tine holders 40. The tamping unit 41 is lifted and lowered by means of the guides 4 via the lifting-lowering cylinder 9. The unit box 5 runs in the guides 4. Reference numeral 21 shows the two transverse displacement drives of the unit frame 1. Reference numeral 2 represents the fixed connection of the outer unit frame 1 with the motion bars or sliding tubes. Reference numeral 3 represents boreholes in the outer unit frame 1 through which the motion bars or sliding tubes protrude for the two tamping units of the opposite side. In the retracted state, the motion bars or sliding tubes for the opposite tamping units protrude from the boreholes 3. This allows the great transverse displacement path by utilising the entire permissible clearance profile. The illustrated arrangement in the triangle of the guide rods or guide tubes 2 produces a very high stiffness of the unit frame 1 against vertical, transverse and torsional movements.