HAND-HELD TAMPING MACHINE FOR COMPACTING TRACK BALLAST

Abstract

A hand-held tamping machine for compacting track ballast has a tamping pick for penetrating the track ballast, a vibration generator for vibration excitation of the tamping pick, a motor connected with the vibration generator via a drive shaft, and a handle assembly with at least one handle for steering the hand-held tamping machine during operation. Along a shaft axis of the drive shaft the at least one handle is arranged above the machine center of gravity of the hand-held tamping machine by at least 30% of the overall height of the hand-held tamping machine and/or is arranged above the motor center of gravity of the motor by at least 15% of the overall height of the hand-held tamping machine.

Claims

1. A hand-held tamping machine for compacting track ballast, the tamping machine comprising: a tamping pick for penetrating the track ballast; a vibration generator for vibration excitation of said tamping pick; a motor connected with said vibration generator via a drive shaft; a handle assembly with at least one handle for steering the hand-held tamping machine during operation; said at least one handle, along a shaft axis of said drive shaft, being arranged above at least one of: a machine center of gravity of the hand-held tamping machine by at least 30% of an overall height of the hand-held tamping machine; or a motor center of gravity of said motor by at least 15% of the overall height of the hand-held tamping machine.

2. The hand-held tamping machine according to claim 1, wherein along the shaft axis said at least one handle is arranged above the machine center of gravity by at least 40% of the overall height of the hand-held tamping machine.

3. The hand-held tamping machine according to claim 1, wherein along the shaft axis the machine center of gravity is arranged at a maximum of 60% of the overall height of the hand-held tamping machine below said at least one handle.

4. The hand-held tamping machine according to claim 1, wherein along the shaft axis said at least one handle is arranged above the motor center of gravity by at least 20% of the overall height of the hand-held tamping machine.

5. The hand-held tamping machine according to claim 1, wherein along the shaft axis a distance between said at least one handle and a vibration nodal point of the hand-held tamping machine that is due to the vibration excitation by said vibration generator is a maximum of 15% of the overall height of the hand-held tamping machine.

6. The hand-held tamping machine according to claim 5, wherein the vibration nodal point is caused by at least one of a rigid-body motion or an elastic deformation of the hand-held tamping machine.

7. The hand-held tamping machine according to claim 1, comprising a first vibration decoupler operatively disposed between said tamping pick and at least one of the handle assembly or said motor.

8. The hand-held tamping machine according to claim 7, wherein said first vibration decoupler has a handle-side connection point and a tamping-pick-side connection point and at least one of said handle-side connection point or said tamping-pick-side connection point of said first vibration decoupler is arranged above the machine center of gravity.

9. The hand-held tamping machine according to claim 7, wherein a distance of said at least one handle from the motor center of gravity and a distance of the motor center of gravity from said handle-side connection point of said first vibration decoupler have a ratio in a range from 1:1 to 4:1.

10. The hand-held tamping machine according to claim 7, wherein along the shaft axis a distance between said tamping-pick-side connection point of said first vibration decoupler and the machine center of gravity is a maximum of 15 of the overall height of the hand-held tamping machine.

11. The hand-held tamping machine according to claim 7, wherein along the shaft axis a distance between said handle-side connection point of said first vibration decoupler and the machine center of gravity is a maximum of 20% of the overall height of the hand-held tamping machine.

12. The hand-held tamping machine according to claim 7, further comprising a second vibration decoupler and wherein at least one of said first vibration decoupler or said second vibration decoupler is arranged completely above the machine center of gravity.

13. The hand-held tamping machine according to claim 1, further comprising a second vibration decoupler operatively disposed between said handle assembly and at least one of said tamping pick or said motor.

14. The hand-held tamping machine according to claim 1, wherein said motor is a combustion engine or an electric motor.

15. The hand-held tamping machine according to claim 1, further comprising a tamping pick tube, and wherein said vibration generator is arranged at least in sections in said tamping pick tube.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0040] FIG. 1 is a front elevation view of a hand-held tamping machine for compacting track ballast, having a tamping pick for penetrating the track ballast, a vibration generator, a motor for driving the vibration generator in rotation, and a handle assembly for steering the hand-held tamping machine in operation; and

[0041] FIG. 2 is a longitudinal sectional view of the hand-held tamping machine of FIG. 1 through an axis of rotation of a drive shaft, which connects the motor to the vibration generator in a torque-transmitting manner.

DETAILED DESCRIPTION OF THE INVENTION

[0042] Referring now to the figures of the drawing in detail, there is shown a hand-held tamping machine 1 for compacting track ballast 2. Track rails 3 are attached to track sleepers 4, which rest on the track ballast 2. In FIG. 1, the hand-held tamping machine 1 is shown in operation, with the hand-held tamping machine 1 penetrating the track ballast 2 in a vertical orientation to a depth below the track sleepers 4 for compacting the track ballast 2.

[0043] The hand-held tamping machine 1 has a tamping pick 5, a vibration generator 6, a motor 7 and a handle assembly 8. The tamping pick 5 comprises a tamping pick tube 9 and a ballast contact attachment 10 which surrounds the tamping pick tube 9 at least in sections. The ballast contact attachment 10, which is subject to wear, is replaceably attached to the tamping pick tube 9.

[0044] The vibration generator 6 is configured to excite the tamping pick 5 to vibrate. The motor 7 and the vibration generator 6 are configured to induce a vibration frequency in a range from 20 Hz to 100 Hz, in particular from 30 Hz to 60 Hz. The vibration generator 6 has an eccentric shaft 11 which is rotatably mounted in the tamping pick tube 9 about an eccentric axis 12 by means of two tubular bearings 13a, 13b. An imbalance mass 14 is attached to the eccentric shaft 11. In a direction perpendicular to the eccentric axis 12, the imbalance mass 14 is completely overlapped by the tamping pick tube 9 and the ballast contact attachment 10.

[0045] The engine 7 is an internal combustion engine, in particular a gasoline-driven engine. Alternatively, the motor 7 may also be configured as an electric motor. In order to drive the vibration generator 6 in rotation, the motor 7 is connected to it via a drive shaft 15. The drive shaft 15 is rotatably mounted about a shaft axis 16. The drive shaft 15 is connected with the eccentric shaft 11 in a reversibly detachable and torque-transmitting manner. The drive shaft 15 can alternatively be non-detachably connected with the eccentric shaft 11, in particular be configured as one piece with it. The eccentric shaft 11 and the drive shaft 15 are configured coaxially.

[0046] The handle assembly 8 has two handles 17a, 17b. The handles 17a, 17b comprise a plastic material, in particular they are configured as rubber handles. The motor 7 has a power adjustment element 18, in particular a throttle lever, for regulating the power output. The power adjustment element 18 is arranged at the first handle 17a such that the user does not have to take his hand off the handle 17a to adjust the motor power.

[0047] The handles 17a, 17b are connected with the motor 7 and the tamping pick 5 via a support structure 19. The support structure 19 is a tubular structure which is basically made of metal.

[0048] The hand-held tamping machine 1 has a first vibration decoupler 20 and a second vibration decoupler 21. The first vibration decoupler 20 acts between the tamping pick 5 and the handle assembly 8 and the motor 7. For this purpose, the first vibration decoupler 20 is connected to the tamping pick 5 via a tamping-pick-side connection point 22. A handle-side connection point 23 of the first vibration decoupler 20 is connected with the handle assembly 8 and the motor 7. In particular, the first vibration decoupler 20 is attached to a pick support structure 24 via the tamping-pick-side connection point 22. The first vibration decoupler 20 is attached to a head support structure 25 via the handle-side connection point 23. The head support structure 25 is configured as a supporting plate. The motor 7 is attached, in particular rigidly, to the head support structure 25.

[0049] The second vibration decoupler 21 acts between the handle assembly 8 and the tamping pick 5 as well as the motor 7, in particular the head support structure 25. For this purpose, the second vibration decoupler 21 is connected with the tamping pick 5 via a tamping-pick-side connection point 26, in particular attached to the head support structure 25. The second vibration decoupler 21 is connected with the handle assembly 8, in particular attached to the support structure 10, via a handle-side connection point 27.

[0050] Each of the first vibration decoupler 20 and the second vibration decoupler 21 comprises four decoupling elements 28a, 28b, respectively, made of a rubber-elastic material. The decoupling elements 28a of the first vibration decoupler are connected in parallel with each other. The decoupling elements 28b of the second vibration decoupler 21 are also connected in parallel with each other. The second vibration decoupler 21 is connected in series with the first vibration decoupler 20.

[0051] The two vibration decouplers 20, 21 each allow limited relative movement of the tamping-pick-side connection points 22, 26 with respect to the handle-side connection points 23, 27 in all spatial directions.

[0052] For power transmission between the motor 5 and the vibration generator 6 while tolerating corresponding relative movements, the drive shaft 15 is configured in two portions. A third vibration decoupler 31 acts between a first drive shaft portion 29 and a second drive shaft portion 30. The first drive shaft portion 29 is connected to the second drive shaft portion 30 via the third vibration decoupler 31 in a torque-transmitting manner. The third vibration decoupler 31 allows a limited displacement of the first drive shaft portion 29 relative to the second drive shaft portion 30 along the shaft axis 16, and a limited relative swiveling movement about any axis perpendicular to the shaft axis 16.

[0053] The hand-held tamping machine 1 has an overall height H of 1060 mm, which corresponds to the overall dimension of the hand-held tamping machine 1 along the shaft axis 16. A machine center of gravity SP0 is located along the shaft axis 16 in the center of the hand-held tamping machine 1. The machine center of gravity SP0 is arranged at a distance hG0 of 530 mm from the handles 17a, 17b.

[0054] Distances with respect to the at least one handle 17a, 17b are measured towards the upper side of the handle 17a, 17b. In general, when determining the masses and dimensions of the hand-held tamping machine 1, it is assumed that the hand-held tamping machine 1 is in an operational state, in which in particular the ballast contact attachment 10 is attached to the tamping pick tube 9 and/or a fuel tank 32 of the motor 7 is, say, half-way filled with fuel.

[0055] A motor center of gravity SPM is arranged below the handles 17a, 17b at a distance hGM of 240 mm from the handles 17a, 17b. Accordingly, a distance h0M between the machine center of gravity SP0 and the motor center of gravity SPM is 290 mm.

[0056] The handle-side connection point 23 of the first vibration decoupler 20 is arranged at a distance hT0 of 120 mm from the machine center of gravity SP0. Consequently, a distance hMT between the motor center of gravity SPM and the handle-side connection point 23 is 170 mm, and the distance hGM between the motor center of gravity SPM and the handles 17a, 17b is 240 mm. A distance ht0 between the machine center of gravity SP0 and the tamping-pick-side connection point 22 of the first vibration decoupler 20 is 60 mm.

[0057] A distance h0F between the machine center of gravity SP0 and a force application point KP of the resulting eccentric force F provided by the vibration generator 6 is 383 mm.

[0058] The mode of operation of the hand-held tamping machine 1 is as follows:

[0059] The hand-held tamping machine 1 is in an operable state, with the fuel tank 32 half-filled and the ballast contact attachment 10 attached to the tamping pick tube 9. The user grips the hand-held tamping machine 1 by the handles 17a, 17b to carry it to the location of the track ballast 2 to be compacted. The motor 7 is started and drives the vibration generator 6 according to the power set by the power adjustment element 18. The vibration generator 6 causes the tamping pick 5 to vibrate. Steered by the user via the handles 17a, 17b and under the action of the weight of the hand-held tamping machine 1, the tamping pick 5 penetrates the track ballast 2.

[0060] The tamping pick 5 transmits the vibrational motion to the track ballast 2, which is compacted as a result. To support the tamping of the track sleeper 4, the user can swivel the hand-held tamping machine 1 about a horizontal axis oriented in particular parallel to the respective track sleeper 4. As a result, compaction of the track ballast 2 below the track sleeper 4 can be achieved particularly efficiently and reliably.

[0061] The vibrations excited at the handles 17a, 17b result at least in part from a rigid-body motion of the hand-held tamping machine 1. In FIG. 1, the shaft axis 16 is illustrated in the vertical orientation of the hand-held tamping machine 1. The shaft axis 16′ drawn in obliquely to the vertical direction symbolizes the rigid-body motion of the track tamping machine 1 resulting from the eccentric force F. Here, the resulting vibration amplitude is shown greatly exaggerated. The limited rigidity of the hand-held tamping machine 1, in particular of the vibration decouplers 20, 21, is not taken into account in the rigid-body vibration. In a vibration nodal point SKP, the position of which depends on the mass distribution of the hand-held tamping machine 1, a minimum of the vibration amplitude prevails, in particular it is zero. Along the shaft axis 16, a distance hGP between the handles 17a, 17b and the vibration nodal point SKP is 60 mm. Due to the proximity of the handles 17a, 17b to the vibration nodal point SKP, the respective vibration amplitude prevailing at the handles 17a, 17b is particularly low.

[0062] The vibration decouplers 20, 21, 31 reduce the vibrations transmitted from the tamping pick 5 and/or the vibration generator 6 to the handle assembly 8, in particular the handles 17a, 17b, and the motor 7. As a result, the service life of the motor 7 can be extended due to reduced stresses. Furthermore, a considerable relief of the operator results.

[0063] The large distance hGM between the handles 17a, 17b and the motor center of gravity SPM, particularly in relation to the height H, has a particularly advantageous effect on the ease of use. The source of noise and/or exhaust emissions, when the motor is a gasoline engine, formed by the motor 7 is thus particularly far away from the user's head. In addition, the motor 7 is arranged particularly close to the machine center of gravity SP0, as a result of which the motor 7 is subjected to particularly low vibration loads due to increased inertial damping prevailing there.

[0064] It has been found that the reaction forces acting on the user via the handles 17a, 17b are dependent on the afore-mentioned distances, in particular the arrangement of the machine center of gravity SP0, the motor center of gravity SPM, the force application point KP and the handles 17a, 17b along the shaft axis 16. The prevailing selection of the distances results in particular in the arrangement of the handles 17a, 17b close to the vibration nodal point SKP. In the prevailing hand-held tamping machine 1, the reaction forces acting on the user or the vibration excitation at the handles 17a, 17b are particularly low. The hand-held tamping machine 1 is thus particularly user-friendly in operation.