APPARATUS FOR TRACK MACHINING, METHOD FOR OPERATING THE APPARATUS FOR TRACK MACHINING AND TAMPING ASSEMBLY

Abstract

An apparatus for track machining contains a fastening device, at least one machining device and at least one vibration decoupler operating between the at least one machining device and the fastening device and having adjustable stiffness and/or adjustable damping for at least partially decoupling a movement of the fastening device from a movement of the at least one machining device.

Claims

1. An apparatus for track machining, the apparatus comprising: a fastening device; at least one machining device for at least one of compacting a track bed and for tightening and loosening a screw connection; and at least one vibration decoupler with at least one of an adjustable stiffness and an adjustable damping to at least partially decouple said fastening device and said at least one machining device.

2. The apparatus according to claim 1, further comprising an adjusting means that is in signal communication with said at least one vibration decoupler, for adjusting at least one of the stiffness and the damping.

3. The apparatus according to claim 2, further comprising a drive unit connected to said adjusting means for providing at least one of a fluidic and mechanical signal for automated adjustment of at least one of the stiffness and the damping.

4. The apparatus according to claim 1, wherein said at least one vibration decoupler has a chamber filled with a fluid for at least proportional transmission of forces between said fastening device and said at least one machining device via the fluid.

5. The apparatus according to claim 4, wherein said chamber has a reversibly deformable chamber wall.

6. The apparatus according to claim 4, further comprising a pressure regulating unit for controlling a pressure of the fluid in said chamber.

7. The apparatus according to claim 4, wherein said at least one vibration decoupler has an adjustable throttle valve for limiting a flow of the fluid.

8. The apparatus according to claim 1, wherein said at least one vibration decoupler has a braking unit for adjustable braking of said at least one machining device relative to said fastening device.

9. The apparatus according to claim 1, further comprising at least one machine motor for providing power required for operating said at least one machining device, said at least one machine motor is disposed with respect to said at least one vibration decoupler on a side of said at least one machining device.

10. The apparatus according to claim 1, wherein said at least one machining device has a tamping unit for track bed treatment.

11. The apparatus according to claim 10, wherein said at least one machining device has a vibration generator for generating a vibratory movement.

12. The apparatus according to claim 1, wherein said at least one machining device has a screwing unit for at least one of tightening and loosening the screw connection.

13. The apparatus according to claim 12, wherein said at least one machining device has a plurality of screwing units.

14. The apparatus according to claim 12, further comprising a clamping device for reversibly fastening said at least one machining device to a rail.

15. The apparatus according to claim 12, further comprising a feeding device for providing screw members.

16. The apparatus according to claim 1, wherein said at least one machining device has a cutting tool for cutting off a screw bolt.

17. The apparatus according to claim 1, further comprising a displacement device for at least one of displacing and pivoting said at least one machining device relative to said fastening device.

18. The apparatus according to claim 17, further comprising at least two tamping units being at least one of displaceable relative to one another and pivotable relative to one another by means of said displacement device.

19. The apparatus according to claim 1, further comprising a positioning device, to which said fastening device is attached, for positioning said at least one machining device on a track.

20. The apparatus according to claim 19, wherein said positioning device has a multi-axis robot to which said fastening device is attached.

21. The apparatus according to claim 19, wherein said positioning device has a carriage.

22. The apparatus according to claim 21, further comprising a fixing unit for detachably fixing said at least one machining device to said carriage.

23. The apparatus according to claim 1, further comprising a sensor for at least one of detecting at least one of a position and an orientation of an object to be machined of a track and for monitoring a working space.

24. A method for operating an apparatus for track machining, which comprises the steps of: providing at least one machining device disposed on a vibration decoupler; adjusting the vibration decoupler between a first coupling state in which the vibration decoupler has at least one of a first stiffness and a first damping, and a second coupling state in which the vibration decoupler has at least one of a second stiffness different from the first stiffness and a second damping different from the first damping; and performing at least one of compacting a track bed and tightening and loosening a screw connection by means of the at least one machining device.

25. The method according to claim 24, which comprises displacing the at least one machining device from a restoring position to a working position, wherein the vibration decoupler is set to the first coupling state.

26. The method according to claim 24, which further comprises machining a track, wherein the vibration decoupler is set to the second coupling state.

27. The method according to claim 24, which further comprises performing at least one of tightening and loosening two screw connections of a track at least one of one after the other and simultaneously.

28. The method according to claim 27, wherein two rotatably drivable screwing units are engaged simultaneously with one of the screw connections in each case.

29. The method according to claim 24, which further comprises locking the at least one machining device to at least one rail when machining a track.

30. The method according to claim 24, wherein the machining of a track takes place on a frog of a turnout.

31. A tamping assembly for track bed treatment, comprising: a fastening device; a machine motor; at least one tamping unit having a penetrator, being formed as a tamping pick tube, and a vibration generator, wherein at least one of said vibration generator and said machine motor is disposed in said tamping pick tube; and a displacement device for at least one of displacing and pivoting said at least one tamping unit relative to said fastening device.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0087] FIG. 1 is a diagrammatic, perspective view of an apparatus for track machining with a carriage for traveling on rails, a multi-axis robot attached thereto, a fastening device attached to the multi-axis robot, and two machining devices, wherein a plurality of vibration decouplers act between the fastening device and the machining devices;

[0088] FIG. 2 is a side view of the apparatus in FIG. 1, wherein the machining devices each have a tamping unit for track bed treatment;

[0089] FIG. 3 is a side view of the multi-axis robot with the machining devices attached thereto in FIG. 1;

[0090] FIG. 4 is a front view of the fastening device, the vibration decoupler, the machining devices and a housing, wherein the vibration decoupler is shown in section;

[0091] FIG. 5 is a front view of the fastening device, the vibration decoupler and the machining devices according to FIG. 4 without the housing to illustrate a displacement device for pivoting the two machining devices relative to each other, which displacement device is arranged in a penetration position;

[0092] FIG. 6 is a front view of the fastening device, the vibration decoupler and the machining devices according to FIG. 5, wherein the displacement device is arranged in a feed position;

[0093] FIG. 7 is a perspective view of the apparatus for track machining according to a further embodiment, wherein the two machining devices each have a screwing unit for tightening and/or loosening a screw connection;

[0094] FIG. 8 is a front view of the fastening device, the vibration decouplers and the two machining devices in FIG. 7 and a displacement device for moving the machining devices parallel and perpendicular to a tool engagement direction; and

[0095] FIG. 9 is a perspective illustration of the apparatus for track machining according to a further embodiment with a carriage, two multi-axis robots attached thereto and in each case a fastening device attached to the respective multi-axis robot, on which in each case two of the machining devices are arranged via a vibration decoupler acting therebetween.

DETAILED DESCRIPTION OF THE INVENTION

[0096] Referring now to the figures of the drawings in detail and first, particularly to FIGS. 1 to 6 thereof, there is shown a first embodiment example of an apparatus 1 for track machining. The apparatus 1 has a positioning device 2 with a carriage 3 for traveling on rails 4 and a multi-axis robot 5. The carriage 3 has a traction drive 6 for displacing the carriage 3 along the rails 4. A supply unit 7, a control unit 8, and a bearing unit 9 are arranged on the carriage 3.

[0097] The multi-axis robot 5 is attached to the bearing unit 9. The multi-axis robot 5 has six pivot joints 10 for displacing a robot head 11 relative to the bearing unit 9. An arm section 12 of the multi-axis robot 5 is disposed between each of the pivot joints 10.

[0098] The apparatus 1 has a fastening device 13, which is reversibly detachably attached to the positioning device 2, in particular to the robot head 11. Two machining devices 14 are connected to the fastening device 13. Vibration decouplers 15a, 15b act between the machining devices 14 and the fastening device 13. The vibration decouplers 15a, 15b are configured to decouple a movement of the fastening device 13 at least partially from a movement of the machining devices 14. The stiffness and damping behavior of the vibration decouplers 15a, 15b can be set.

[0099] The fastening device 13 has a quick release coupling 16 for a reversible connection to the robot head 11. Furthermore, the fastening device 13 has a fluid coupling 17, via which fluids, in particular hydraulic oil and compressed air, can be transmitted.

[0100] The two machining devices 14 each contain a tamping unit 18 for track bed treatment, in particular for compacting the track bed 19. The respective tamping unit 18 has a penetrator 20 for penetrating the track bed 19 and a vibration generator 21 for generating a vibration movement at the penetrator 20. The penetrator 20 is formed as a tube, which is also referred to as a tamping pick tube. The respective vibration generator 21 is disposed in the associated penetrator 20. The vibration generator 21 comprises an eccentric mass, which is not shown and is mounted eccentrically with respect to an axis of rotation, for generating the vibration movement. The two vibration generators 21 of the tamping units 18 can each be driven in rotation by a machine motor 22 or drive motor of the tamping units 18. The machine motors 22 are electrically driven. The required electrical power is provided via a current coupling 23 of the fastening device 13. The machine motors 22 are arranged with respect to the vibration decouplers 15a, 15b on the sides of the tamping units 18.

[0101] A displacement device 24 of the apparatus 1 is configured for pivoting the respective machining device 14, in particular the respective tamping unit 18, relative to the fastening device 13. For this purpose, the respective machining device 14 is connected to the fastening device 13 via a feed joint 25 of the displacement device 24. A piston cylinder unit 26 of the displacement device 24 produces the actuating force Fs required for pivoting the respective machining device 14. By means of the displacement device 24, the two tamping units 18 can also be pivoted relative to one another or toward each other.

[0102] The vibration decouplers 15a, 15b comprise a fastening decoupling unit 15a attached to the fastening device 13 and a machining decoupling unit 15b attached to each of the two machining devices 14. The fastening decoupling unit 15a and the machining decoupling units 15b each comprise at least one chamber 27, which can be filled with a fluid, for at least proportionally transmitting reaction forces F.sub.R between the fastening device 13 and the machining devices 14 via the fluid.

[0103] The fastener decoupling unit 15a is construed to control a displacement movement of the machining device 14 relative to the fastening device 13 along a penetration direction 28 of the penetrator 20 into the track bed 19. The machining decoupling units 15b are construed to control the movements of the respective machining device 14 relative to the fastening device 13 along and perpendicular to the penetration direction 28. To control these relative movements, the pressure p.sub.1, p.sub.2, p.sub.3 of the fluid within the chambers 27 is adjustable. In order to limit the relative movements to a linear degree of freedom of movement, the fastening decoupling unit 15a contains a linear guide 29. The machining decoupling units 15b do not comprise a guide of this type. The chambers 27 of both vibration decouplers 15a, 15b comprise a reversibly deformable chamber wall 30. A restriction of the relative movement to certain degrees of freedom of movement between the machining devices 14 and the fastening device 13 is not effected by the machining decoupling unit 15b.

[0104] All of the chambers 27 of the vibration decouplers 15a, 15b are connected to the supply unit 7 via fluid connections 31, in particular via the fluid coupling 17. The fluid pressure p.sub.1, p.sub.2, p.sub.3 within the respective chamber 27 is adjustable by means of the control unit 8 connected to the supply unit 7. The fluid is compressed air.

[0105] The fastening decoupling unit 15a is configured as a piston cylinder unit. The chambers 27 of the machining decoupling units 15b are configured as rubber bellows. Depending on the pressure p.sub.1, p.sub.2, p.sub.3, the rigidity of the respective vibration decoupler 15a, 15b is adjustable. As the pressure p.sub.1, p.sub.2, p.sub.3 increases, the respective vibration decoupler 15a, 15b is biased more strongly into a rest position in which the volume V enclosed by the respective chamber 27 is at a maximum. The vibration decouplers 15a, 15b arranged in a deflection position cause a restoring force to the rest position which depends on the pressure p.sub.1, p.sub.2, p.sub.3.

[0106] A piston 32 of the fastening decoupling unit 15a, which is designed as a piston cylinder unit, is displaceably mounted in a cylinder 33 and delimits two annular chambers 27 from one another. A spiral spring 33a acts between the piston 32 and the cylinder 33. Via a fluid line 34, which is in fluid-conducting connection with the fluid coupling 17, the pressure p.sub.1, p.sub.2 in the chambers 17 can be adjusted. The two chambers 27 of the fastening decoupling unit 15a are connected to one another in fluid-conducting manner via an electrically controllable throttle valve 35. The throttle valve 35 is in signal-transmitting connection with the control unit 8. In particular, the throttle valve 35 is connected to the current coupling 23 via a current line 36.

[0107] The apparatus 1 further contains a sensor device 37 for detecting the position of sleepers 38 of the track, in particular the arrangement of the machining devices 14 relative to the track bed 19. The sensor device 37 is further configured to monitor a working space 39, in particular to detect whether objects or persons are located in the working space 39. For this purpose, the sensor device 37 contains two cameras 40 and a ground radar 41. A triangulation unit 42 and a GPS module 43 serve to precisely determine the position of the apparatus 1 along the rails 4. The working space 39 is bounded downwardly by the track bed 19 and laterally, forwardly and rearwardly by a frame bridge 39a, which connects a front part of the carriage 3 to a rear part of the carriage 3.

[0108] For securely fastening the machining device 14 to the carriage 3 when displacing the apparatus 1 along the rails 4, the apparatus 1 contains a fixing unit 44. The fixing unit 44 is configured as a supporting frame in which the displacement device 24 can be hooked from above, in particular by means of the multi-axis robot 5.

[0109] The functional principle of the apparatus 1 is now described.

[0110] The carriage 3 is arranged on the rails 4. The machining devices 14 are suspended in the fixing unit 44 via the displacement device 24. The displacement device 24 is in the penetration position. The pressure p.sub.1, p.sub.2, p.sub.3 in the chambers 27 of the vibration decouplers 15a, 15b corresponds to the ambient pressure.

[0111] The traction drive 6 is activated and the carriage 3 is displaced along the rails 4 to the object to be machined, in particular to the track bed 19 to be compacted. The arrangement of the apparatus 1 at the region of the track bed 19 to be treated is controlled by means of the control unit 8. For this purpose, the information acquired by the sensor device 37, in particular the information acquired by the triangulation unit 42 and the GPS module 43, is processed in the control unit 8. The precise determination of the sleeper 38 of the track to be tamped by means of the machining devices 14 is carried out by means of the cameras 40.

[0112] By means of the multi-axis robot 5, the fastening device 13 and the machining devices 14 attached thereto are removed upward from the fixing unit 44 and arranged above the section of the track bed 19 to be treated. The two machining devices 14 are arranged in mirror symmetry with respect to a vertical plane through a central longitudinal axis of the corresponding sleeper 38. The multi-axis robot 5 is controlled by means of the control unit 8. The apparatus 1 is in the restoring position.

[0113] Via a pressure regulating unit 45 of the control unit 8, the chambers 27 of the vibration decouplers 15a, 15b are pressurized with compressed air, in particular via the fluid lines 34. The pressure p.sub.1, p.sub.2, p.sub.3 in the chambers 27 rises, the rigidity of the vibration decouplers 15a, 15b increases and the vibration decouplers 15a, 15b are arranged in the rest position. The pressure p.sub.1, p.sub.2 in the chambers 27 of the fastening decoupling unit 15a is 100 bar, for example. The pressure p.sub.3 in the chambers 27 of the machining decoupling unit 15b is 25 bar, for example. The vibration decouplers 15a, 15b are set to the first coupling state with a first stiffness in each case.

[0114] Based on a signal from the control unit 8, the multi-axis robot 5 lowers the machining devices 14 downward in the vertical direction. The penetrators 20 of the machining devices 14 penetrate the track bed 19. Due to the fact that the vibration decouplers 15a, 15b are stiffened by the pressure p.sub.1, p.sub.2, p.sub.3 in the chambers 27, the positioning of the penetrators 20 in the track bed 19 can be performed particularly precisely. The apparatus 1 is in the penetration position illustrated in FIG. 5.

[0115] By means of the pressure regulating unit 45, the pressure in the chambers 27 is reduced based on a corresponding signal from the control unit 8. The pressure p.sub.1, p.sub.2 in the chambers 27 of the fastening decoupling unit 15a is 10 bar, for example. The pressure p.sub.3 in the chambers 27 of the machining decoupling unit 15b is 5 bar, for example. A respective second stiffness of the vibration decouplers 15a, 15b is reduced in the second coupling state compared to the first stiffness when entering the track bed 19. A second damping of the fastening decoupling unit 15a in the second coupling state is variable by means of the throttle valve 35 and adjustable differently from the first damping in the first coupling state.

[0116] The machine motors 22 of the machining devices 14 are supplied with electrical power by the control unit 8, in particular via the power coupling 23 and the power lines 36. The machine motors 22 drive the vibration generators 21 of the machining devices 14. This generates a vibration movement and transmits it to the penetrators 20

[0117] The piston cylinder units 26 of the displacement device 24 are supplied with hydraulic fluid, which is provided by the supply unit 7 and conducted to the piston cylinder units 26 via the fluid coupling 17 and the fluid lines 34. The actuating forces Fs produced at the piston cylinder units 26 cause a pivoting movement of the machining devices 14 about the feed joints 25. The displacement device 24, in particular the machining devices 14, is in the feed position illustrated in FIG. 6.

[0118] When the penetrators 20 are displaced into the track bed 19, due to the vibration movement and due to the pivoting of the penetrators 20 immersed in the track bed 19, reaction forces F.sub.R act on the machining device 14. The reaction forces F.sub.R are transmitted to the fastening device 13 via the machining decoupling unit 15b, the displacement device 24, and the fastening decoupling unit 15a. In this case, the transmission of the reaction forces F.sub.R takes place at least proportionally via the compressed air introduced into the chambers 27. As a result of the fact that the pressure p.sub.1, p.sub.2, p.sub.3 during the pivoting of the machining devices 14 about the feed joints 25 is lower than the pressure p.sub.1, p.sub.2, p.sub.3 during the penetration of the track bed 19, the forces transmitted to the fastening device 13 can be reduced. In particular, the reaction forces F.sub.R resulting from the vibration movement of the penetrator 20 are largely cancelled out by the vibration decouplers 15a, 15b. In particular, peak values of the vertical reaction forces F.sub.Rz during the penetration of the track bed 19 are reduced by the vibration decouplers 15a, 15b. The adjustable throttle valve 35 enables an adjustable damping of the vertical relative movement of the machining devices 14 with respect to the fastening device 13.

[0119] The control unit 8 provides a signal for displacing the machining devices 14 by means of the piston cylinder unit 26 into the penetration position. The machining devices 14 pivot back about the feed joints 25 into the penetration position. By means of the multi-axis robot 5, the machining devices 14 are moved back to the restoring position based on a signal from the control unit 8. The vibration decouplers 15a, 15b are returned to the first coupling state.

[0120] The sensor device 37 provides a signal correlating with the position of the adjacent sleeper 38 to the control unit 8. The multi-axis robot 5 displaces the machining devices 14 to the next restoring position above the next section of the track bed 19 to be treated. The further treatment of the track bed 19 is carried out as described above.

[0121] Throughout the entire duration of the track machining, the working space 39 is monitored by the sensor device 37. If a person or an object enters the working space 39, these are detected by the sensor device 37 and a corresponding signal is provided to the control unit 8. The control unit 8 then interrupts the operation of the apparatus 1. In particular, the movements of the multi-axis robot 5, the displacement device 24 and the vibration generator 21 are interrupted. As a result, the operation of the apparatus 1 can be carried out in a particularly safe manner.

[0122] The carriage 3 is configured as a multi-path vehicle. For this purpose, in addition to a rail undercarriage 46 for driving on the rails 4, the carriage 3 contains an additional undercarriage 47. The additional undercarriage 47 can be displaced in the vertical direction, in particular between a position above the rail undercarriage 46 and a position below the rail undercarriage 46. The additional undercarriage 47 is configured to travel over uneven surfaces and roads. In particular, the additional undercarriage 47 is designed to displace the apparatus 1 between two adjacent tracks, in particular perpendicular to the longitudinal extension of the rails 4. This considerably increases the flexibility of use of the apparatus 1.

[0123] Due to the fact that the vibration decouplers 15a, 15b act between the machining devices 14 and the fastening device 13, the positioning device 2, in particular the carriage 3 with the multi-axis robot 5, is subjected to considerably less mechanical load and its wear is reduced. The positioning device 2 can thus be designed to be particularly material-saving and lightweight and can be manufactured and operated particularly economically.

[0124] With reference to FIG. 7 and FIG. 8, a further embodiment example of the invention is described. In contrast to the embodiment example described above, the apparatus 1 has two machining devices 14, each with a screwing unit 48 for tightening and loosening a screw connection 49. Each of the screwing units 48 comprises a machine motor 22 for rotationally driving a screwdriving tool 50 of the screwing unit 48. A socket wrench 51 for rotationally driving the screw connection 49 is reversibly detachably attached to the respective screwdriving tool 50. A displacement device 24, shown only schematically, is configured to displace the two machining devices 14 independently of one another along an engagement direction 52 of the screwdriving tool 50. The displacement device 24 is further configured to move the machining devices 14 relative to each other perpendicular to the engagement direction 52. In particular, in accordance with the previously described embodiment example, the displacement device 24 is configured to displace the respective machining device 14 together with the associated machining decoupling unit 15b.

[0125] The machining decoupling units 15b have an elastically deformable chamber wall 30 in the form of a rubber bellows. The structure of these machining decoupling units 15b is essentially the same as the machining decoupling units 15b according to the embodiment example described above.

[0126] In contrast to the embodiment described above, the fastening decoupling unit 15a comprises a braking unit 53 for adjustable braking of a movement of the machining devices 14 relative to the fastening device 13. The braking unit 53 comprises brake pads 54, which can be reversibly pressed against a brake body 56 by means of a brake actuator 55. By means of the braking unit 53, the damping of a movement transmitted via the fastening decoupling unit 15a can be adjusted on the basis of the contact force FA generated by the brake actuator 55. Decoupling of the movement of the fastening device 13 from the movement of the machining devices 14 is performed by the fastening decoupling unit 15a exclusively along the engagement direction 52. Forces oriented perpendicular to the engagement direction 52 are transmitted via the braking unit 53 and the spring member 33a. No motion decoupling takes place perpendicular to the direction of engagement 52. Corresponding movements are transmitted essentially rigidly via the linear guide 29 of the fastening decoupling unit 15a.

[0127] The apparatus 1 has a clamping device 57, shown only schematically, for reversibly fastening the machining devices 14 to the rails 4. The clamping device 57 is attached to the displacement device 24. The clamping device 57 has an adjusting member, which is not shown, for reversible clamping to the rail 4. The adjusting member can be actuated by means of a signal from the control unit 8.

[0128] Furthermore, the apparatus 1 has a cutting tool 58, shown only schematically in FIG. 8, for cutting off a screw bolt 59 of a seized up screw connection 49 that can no longer be loosened. For this purpose, the cutting tool 58 has a cutting grinding wheel 60 that can be driven in rotation by means of a cutting tool motor 61.

[0129] The apparatus 1 has a feeding device 62 for providing screw members, in particular screws and/or nuts. The feeding device 62 is designed for handling blisters. The screw members can thus be provided in a determinable position and orientation and thus be fed in an automated manner to the machining devices 14, in particular by means of the multi-axis robot 4.

[0130] The functional principle of the apparatus 1 according to the embodiment shown in FIGS. 7 and 8 is now described.

[0131] In accordance with the previously described embodiment example, the apparatus 1 is moved to the object to be machined, in particular to the screw connections 49 to be loosened. The apparatus 1 is in the restoring position. The vibration decouplers 15a, 15b are set to the first coupling state with the higher stiffness compared to the second coupling state.

[0132] The position of the rail 4 and the screw connections 49 is detected by the sensor device 37. Controlled by the control unit 8, the clamping device 57 rigidly attached to the displacement device 24 engages around the rail 4. An actuator of the clamping device 57 is activated by means of the control unit 8. The rail 4 is clamped between clamping jaws of the clamping device 57. The machining devices 14 are supported on the rail 4 via the displacement device 24 and the clamping device 57.

[0133] On the basis of a signal from the control unit 8, the machining devices 14 are positioned by means of the displacement device 24 relative to one another and perpendicular to the engagement direction 52, corresponding to the relative position of the screw connections 49 to one another.

[0134] On the basis of a further signal from the control unit 8, the machining devices 14 are lowered in the engagement direction 52 by means of the multi-axis robot 5. The socket wrenches 51 are brought into engagement with screw heads of the screw bolts 59. The vibration decouplers 15a, 15b are set to the second coupling state with the lower stiffness compared to the first coupling state.

[0135] The machine motors 22 are activated and the socket wrenches 51 are driven in rotation by the screwdriving tools 50. The screwdriving tools 50 are designed as impact wrenches. Seized up screw connections 49 can thus be loosened particularly reliably.

[0136] The vibration decouplers 15a, 15b decouple a movement of the fastening device 13 from the movements of the two machining devices 14. Force peaks of vertical reaction forces F.sub.Rz are cancelled out by the fastening decoupling unit 15a. The vertically resilient mounting due to the linear guide 29 and the spring member 33a prevents transmission of shock-like stresses to the fastening device 13 when the screw connections 49 are contacted in the course of lowering the machining tools 14. Shock-like stresses can thus be counteracted by the mass inertia of the pre-designed components of the apparatus 1, in particular the machining devices 14 and the displacement device 24. The braking unit 53 dampens the vertical movement of the machining devices 14 relative to the fastening device 13, which further reduces the forces acting on the fastening device 13.

[0137] The design of the screwing units 48 as impact screwing units makes it possible to loosen seized up screw connections 49 particularly reliably. The vibrations generated during impact screwing lead in particular to reaction forces F.sub.Rx, F.sub.Ry in the horizontal plane. Force peaks of these reaction forces F.sub.Rx, F.sub.Ry are cancelled out in the machining decoupling devices 15b. The movement of the machining devices 14 is at least proportionally decoupled from the movement of the displacement device 24 by the machining decoupling device 15b.

[0138] After loosening the screw connections 49, the clamping device 57 is detached from the rail 4. The vibration decouplers 15a, 15b are set to the first coupling state with the higher stiffness compared to the second coupling state. By means of the multi-axis robot 5, the machining devices 14 are lifted above the fastening device 13.

[0139] By means of the sensor device 37, it is checked whether the screw connections 49 have been loosened. If at least one of the screw connections 49 is seized up in such a manner that it could not be loosened by means of the screwdriving tool 50, the corresponding screw bolt 59 is cut off. For this purpose, the cutting tool 58 is displaced to the corresponding screw connection 49 by means of the multi-axis robot 5. The vibration decouplers 15a, 15b are here set to the first coupling state. The cutting tool motor 61 is activated and the cutting grinding wheel 60 is fed in the direction of the screw bolt 59. The screw bolt 59 is cut through. The cutting process is completed and the apparatus 1 is moved back to the restoring position.

[0140] The apparatus 1 can also be used for producing, in particular for assembling and tightening screw connections 49. For this purpose, the screwing units 48 are moved to the feeding device 62 by means of the multi-axis robot 5. The vibration decouplers 15a, 15b are here set to the first coupling state. The socket wrenches 51 are inserted into the blisters filled with screws. The screws are held in the socket wrenches 51, for example, by means of a clamping connection, in particular by means of a thrust piece, and/or by means of a magnet, in particular an electromagnet. When the machining devices 14 are displaced in the direction of the screw connection 49 to be produced, the screws are removed from the blister. The screws are inserted into the predetermined screw hole on the basis of a signal from the control unit 8, in particular based on the measured values provided by the sensor device 37.

[0141] By means of the clamping device 57, the machining devices 14 are fastened to the rail 4. The vibration decouplers 15a, 15b are set to the second coupling state. The machine motors 22 are activated. The screw connections 49 are tightened, in particular simultaneously.

[0142] According to a further embodiment not shown, the apparatus 1 does not have a clamping device 57, in contrast to the last embodiment described. The two screwing units 48 of the machining devices 14 are supported against each other when the screw connections 49 are tightened and/or loosened. In particular, the torques transmitted to the respective screw connection 49 are dissipated by corresponding reaction forces F.sub.R, which act on the other screw connection 49 in each case.

[0143] In order to reduce the load on the screw connections 49 caused by these reaction forces F.sub.R, both machining units 14 are not activated simultaneously during the initial loosening and/or the final tightening, but the screwing units 48 are operated alternately. On the other hand, both screwing units 48 are operated simultaneously during the initial tightening and/or the final loosening of the screw connections 49.

[0144] Preferably, the screwing units 48 have a force sensor, in particular a torque sensor. Switching between simultaneous operation and alternating operation of the screwing units 48 is preferably performed using a signal from the respective force sensor, in particular by the control unit 8.

[0145] With reference to FIG. 9, a further embodiment of the invention is described. In contrast to the embodiments described above, the apparatus 1 has two of the multi-axis robots 5, to each of which two of the machining devices 14 are attached via a fastening device 13. The machining devices 14 are configured as screwing units 48. Alternatively, the machining devices 14 can be configured as tamping units 18. The control unit 8 and the supply unit 7 are configured to operate the two multi-axis robots 5 and the machining device 14. Due to the design of the apparatus 1 with the two multi-axis robots 5 and the four machining devices 14, track machining can be performed simultaneously on both rails 4 of the track. The working efficiency of the apparatus 1 is thereby increased once again.

[0146] In contrast to the arrangement at a single bearing unit 9 in a central region between the rails 4, in this embodiment example two of the bearing units 9 are provided for supporting the multi-axis robots 5, which are attached to the carriage 3. The frame bridge 39a is replaced by a central frame support 39b, which runs in particular centrally between the rails 4. The feeding device 62 is arranged on the frame support 39b. The feeding device 62 is thus accessible by all machining devices 14.

[0147] The cameras 40 of the sensor device 37 are arranged in a side region of the carriage 3. The two working spaces 39 are monitored by the sensor device 37 in accordance with the embodiments described above.

[0148] The functional principle of the apparatus 1 corresponds to the functional principle of the apparatuses 1 according to the embodiments described above.

[0149] As a result of the fact that the apparatus 1 has the vibration decouplers 15a, 15b, a movement of the fastening device 13 is at least proportionally decoupled from a movement of the at least one machining device 14. The loads transmitted to the fastening device 13, in particular to the positioning device 2, can thus be significantly reduced. The apparatus 1 is particularly robust and reliable in operation and can be manufactured and operated particularly economically.

[0150] The features of the individual embodiment examples can be combined as required.