Method for tamping ballast supporting track ties

Abstract

In a method for tamping ballast supporting sequentially arranged ties of a track extending in a longitudinal direction, which comprises a tamping cycle at each one of the ties, the tamping cycle comprises lowering a tamping head carrying tamping tools hydraulicallly reciprocable in the longitudinal direction to immerse the tamping tools in the ballast, reciprocating the tamping tools to tamp the ballast, vibrating the tamping tools in a first tamping cycle phase, discontinuing vibration of the tamping tools in a second tamping cycle phase, raising the tamping head to lift the tamping tools out of the ballast, and moving the tamping head from tie to tie.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for tamping ballast supporting sequentially arranged ties of a track extending in a longitudinal direction, which comprises a tamping cycle at each tie. Each tamping cycle comprises lowering a tamping head carrying tamping tools hydraulicallly reciprocable in the longitudinal direction to immerse the tamping tools in the ballast, reciprocating the tamping tools to tamp the ballast, vibrating the tamping tools, raising the tamping head to lift the tamping tools out of the ballast, and moving the tamping head from tie to tie.

2. Description of the Prior Art

Mobile track tampers with tamping heads for tamping ballast supporting track ties are well known, as exemplified by U.S. Pat. Nos. 4,068,595 and 4,240,352, as well as Austrian patent No. 339,358 and EP 0 331 956. As disclosed in the prior art, the tamping tools may be vibrated by a crank drive or by hydraulic impulses applied to a linear drive used for the reciprocation of the tamping tools.

SUMMARY OF THE INVENTION

It is the primary object of this invention to optimize the tamping method outlined hereinabove and to reduce the unfavorable influences of the vibrations.

The above and other objects are accomplished according to the invention with a tamping cycle in which the tamping tools are vibrated in a first tamping cycle phase, and the vibration of the tamping tools is discontinued in a second tamping cycle phase.

This reduces the vibration of the tamping tools to the time when they actually work to tamp the ballast, which means that they are subjected to less wear caused by the vibrations while, at the same time, the environment is relieved of the very loud noise created by the vibrating tamping tools for up to about two third of the time during which the tamping tools were vibrated in conventional methods. In addition, the unpleasant vibrations to which operators are subjected in the operator's cab are greatly reduced.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, advantages and features of the present invention will become more apparent from the following detailed description of a now preferred embodiment thereof, taken in conjunction with the accompanying drawing wherein

FIG. 1 is a schematic side view of a substantially conventional track tamper useful for carrying out the ballast tamping method of this invention;

FIG. 2 is an enlarged side view of the tamping head carried by the track tamper; and

FIG. 3 illustrates the tamping cycle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIGS. 1 and 2, tamping head 1 is vertically movably mounted on frame 11 of mobile track tamper 12 arranged for mobility on track 14 extending in a longitudinal direction and consisting of sequentially arranged ties 4 to which two track rails are fastened. A drive 13 moves the track tamper from tie to tie in a direction indicated by arrow 5.

The tamping head comprises a carrier 7 whereon tamping tools 3, including tamping picks 2, are pivotally mounted. The tamping tools are spaced from each other in the longitudinal direction and are pivotal about pivot axes 6 on carrier 7, upper ends of the tamping tools being linked to one end of linear reciprocating drives 8 for reciprocating the tamping tools in the longitudinal direction. The other end of each reciprocating drive is linked to carrier 7 at 9. A drive 10 connects the tamping head carrier to frame 11 of the track tamper.

Linear reciprocating drives 8 are so constructed (as disclosed in detail, for example, in U.S. Pat. No. 4,068,595, Austrian patent No. 339,358 and EP 0 331 956) that they effect not only a linear reciprocation of the tamping tools in a direction indicated by arrow 15 but also vibrate tamping picks 2 by schematically illustrated vibration drives 18. The reciprocating drives have motion pickups 16 and are controlled by servo valves of a hydraulic installation (well known and not illustrated) to set the velocity of the reciprocating motion and the amplitude, form and frequency of the vibrations.

FIG. 3 illustrates a tamping cycle according to the invention. Line a shows the raised state of tamping head 1 and tamping picks 2, in which, as shown in FIG. 2, tamping picks are raised above tie 4 so that track tamper 12 may be moved without hindrance in the direction indicated by arrow 5. Line b shows the lowered state of tamping picks 2, wherein they are immersed in the ballast for tamping ballast 17 embedding tie 4 for tamping the ballast underneath the tie by reciprocating the tamping picks in the direction indicated by arrows 15. The lowest line t indicates the time of the tamping cycle and vibration frequency f.

The tamping cycle sz at each tie begins with the operation of drive 10 to lower the tamping head from A to b to immerse the tamping tool picks in ballast 17. Subsequently, reciprocating drives 8 are operated to reciprocate the immersed tamping tool picks from B to C to tamp ballast 17 between the reciprocating immersed tamping tool picks 2. After the ballast has been tamped, tamping head 1 is raised from C to D to lift tamping tools 3 out of the ballast, and the tamping head is moved from D to E to the next tie 4.

Parallel to the lowering of the tamping head, vibration drives 18 are operated to vibrate tamping tools 3 in a first tamping cycle phase x during which the tamping tools are lowered from A to B and reciprocated from B to C, and the vibration of the tamping tools is discontinued in a second tamping cycle phase y when tamping head 1 is raised at C and moved from tie to tie from C to E. Thus, tamping cycle sz is comprised of first tamping cycle phase x and a second tamping cycle phase y.

The tamping tools may be vibrated in the first tamping cycle phase in subsequent steps at differing vibration frequencies. Preferably, the tamping tools are vibrated during lowering of the tamping head at a frequency which is higher than the subsequent vibration frequency during the reciprocation of the tamping tools. The tamping head is raised and moved from tie to tie in the second tamping cycle phase.

Claims

1. A method for tamping ballast supporting sequentially arranged ties of a track extending in a longitudinal direction, which comprises a tamping cycle at each one of the ties, the tamping cycle comprising

(a) lowering a tamping head carrying tamping tools hydraulically reciprocable in the longitudinal direction to immerse the tamping tools in the ballast,

(b) reciprocating the tamping tools to tamp the ballast,

(c) vibrating the tamping tools in a first tamping cycle phase,

(d) discontinuing vibration of the tamping tools in a second tamping cycle phase,

(e) raising the tamping head to lift the tamping tools out of the ballast, and

(f) moving the tamping head from tie to tie.

2. The method of claim 1, wherein the tamping tools are lowered and reciprocated to tamp the ballast in the first tamping cycle phase.

3. The method of claim 2, wherein the tamping tools are vibrated in the first tamping cycle phase in subsequent steps at differing vibration frequencies.

4. The method of claim 4, wherein the tamping tools are vibrated during lowering of the tamping head at a frequency which is higher than the subsequent vibration frequency during the reciprocation of the tamping tools.

5. The method of claim 1, wherein the tamping head is raised and moved from tie to tie in the second tamping cycle phase.