GB2135369A

GB2135369A - Travelling railway track tamping machine with two pivotally interconnected machine frames

Info

Publication number: GB2135369A
Application number: GB08406665A
Authority: GB
Inventors: Josef Theurer
Original assignee: Franz Plasser Bahnbaumaschinen Industrie GmbH
Current assignee: Franz Plasser Bahnbaumaschinen Industrie GmbH
Priority date: 1982-09-09
Filing date: 1984-03-14
Publication date: 1984-08-30
Also published as: GB8406665D0; GB2135369B

Abstract

An on-track tamping machine has a main frame or chassis 103 and a sub-frame 109 articulated to it and carrying a ballast tamping unit 124. The sub-frame guides and carries the weight of the tamping unit and possibly of lifting and lining tools and is able to follow the track freely, independently of the main machine frame and its undercarriage. The tamping tools are thereby automatically centred relative to the track. The track lifting and lining unit 118 may be mounted on a further articulated sub-frame 119. By means of a longitudinal drive 115, the sub-frame 109 can be made to move along the track in steps while the main frame moves continuously. <IMAGE>

Description

SPECIFICATION Travelling railway track tamping machine with two pivotally interconnected machine frames This invention relates to a travelling track tamping machine, more particularly a track tamping, levelling and lining machine, comprising two pivotally interconnected frames supported by undercarriages and at least one tamping unit arranged on those frames. U.K. Patent Spec. No.

1337513 describes a track tamping, levelling and lining machine of which the tamping units each associated with one of the two rails are arranged for lateral displacement by drives relative to the machine frame. An inductive sensor is associated with each tamping unit, determining the lateral position of the tamping unit relative to the associated rail and activating the lateral displacement drive of the tamping unit through a followup circuit in such a way that the tamping unit is kept in lateral symmetry to the associated rail and thus follows the curvature of the track. By virtue of the higher technology involved, this arrangement which considerably simplifies operation of the machine is intended primarily for machines of relatively high performance.

It is also known (cf. U.K. Patent Specification No. 1263270) that, in a track tamping, levelling and lining machine equipped-per rail-with two two-sleeper tamping units displaceable relative to one another longitudinally of the machine, that the tamping units can be arranged together on a tamping tool frame which is provided with two undercarriages spaced apart from one another and which is connected to the machine frame for lateral pivoting and displacement by drives to enable the tamping units to be laterally aligned according to the curvature of the track. Since the common tamping tool frame has to absorb the weight and operational forces of all four tamping units, the frame construction has to be relatively solid and the associated lateral displacement drives rated accordingly.

In addition, U.K. Patent Specn. No. 11 66278 describes a multi-sleeper tamping machine in which the tamping units each associated with one of the two rails are mounted one behind the other longitudinally of the machine on a separate tool frame which is arranged between the two main undercarriages of the machine and which is laterally guided on the track by separate undercarriages spaced apart from one another. The tool frame is pivotally connected to the main machine frame through vertical displacement drives and is equipped in the vicinity of its undercarriages with rail grippers for lifting the track aligned by track correcting tools at the rear end of the machine.

This arrangement enables the track to be lifted in stages to its prescribed level in two successive operations.

In another known tamping machine which is equipped with three undercarriages spaced apart from one another longitudinally of the machine (cf. U.K. Patent Specn. No. 1288283) the track lifting and lining unit and the tamping units are arranged between the central undercarriage and the rear undercarriage (in the working direction) whilst the front undercarriage (in the working direction) is mounted on the machine frame in such a way that it can be displaced longitudinally of the machine and also raised and lowered.In this way, the machine frame can be supported either by the front undercarriage or by the central undercarriage and the distance of this front point of support of the machine frame from the track lifting and lining unit can be coordinated with the particular degree of lift required for the track in such a way that the rails to be raised from their original level to the prescribed level over this length of the track are merely elastically deformed and do not undergo any deformation which exceeds the permitted limit, i.e. any permanent deformation. The fact that the machine frame can be supported by the front undercarriage enables the track to be lifted to a fairly considerable extent. On the other hand, the displaceable arrangement of the front undercarriage enables the inter-axle distance of the machine prescribed for in-transit runs to be maintained.

U.K. Patent Specification No. 1320205 describes a continuously advancing tamping, levelling and lining machine of which the working units are mounted for displacement by drives on longitudinal guides of the main machine frame and are designed to advance step-by-step via control systems for one tamping position to the next independently of the continuous advance of the main frame. Similar arrangements for the combined use, i.e. for the coupling, of track construction vehicles advancing partly continuously and partly in steps are described in British Patent No. 1 267,322.

Finally, U.K. Patent Specn. No. 1361406 describes a multi-sleeper tamping machine which, for example in the embodiment illustrated in Figure 8 of the British Patent in question, is in the form of a double machine comprising two frames each supported by two undercarriages spaced apart from one another and joined pivotally to one another by a linear displacement drive. Each of the two frames is equipped with a track lifting and lining unit and with one tamping unit for each rail. The longitudinal displacement drive enables the tamping units both of the front and of the rear frame (or machine section) to be centred over the particular sleepers below which the ballast is to be tamped, irrespective of the intervals between them.Although the provision of a common levelling reference system provides for certain simplifications by comparison with individual machines used in tandem, the overall cost of these double machines provided with frames separately guided on the track both in terms of construction and in terms of control systems is nevertheless relatively high.

The object of the present invention is to provide a travelling track tamping machine of the type referred to at the beginning which, in regard to the arrangement of the tamping units, is even more simple in construction and is characterised by a better association with the lateral and vertical trend of the track.

According to the invention, there is provided a travelling track tamping, levelling, and lining machine comprising a main machine frame supported on longitudinally spaced undercarriages, a tool support frame disposed between two longitudinally spaced undercarriages of the main machine frame, the tool support frame being provided with a single undercarriage for supporting the tool support frame on the track, and being coupled in articulated manner to the main machine frame at a position longitudinally spaced from the said single undercarriage, the coupling between the said frames being such that the tool support frame can be moved longitudinally relative to the main frame, a drive for effecting such movement, at least one tamping unit carried by the tool support frame directly forward of the said single undercarriage, and a lifting and lining unit forward of the tamping unit together with lifting and lining drives.

This construction of the machine according to the invention makes it possible for the tamping units independently and accurately to follow the lateral and vertical trend of the track and, hence, for the tamping tines designed to penetrate into the ballast bed on both sides of the associated rail to be accurately centred in relation to the longitudinal axis thereof. Since, in general, from four to sixteen tamping tines have to be simultaneously aligned relative to the associated rail for each tamping unit, this automatic centring of the tamping units is extremely important so far as efficient, uninterrupted tamping is concerned.

This advantage is achieved by the single undercarriage-in the form of a free steering axle automatically following the longitudinal trend of the track-of the tool support pivotally connected to the other end of the main machine frame without any need for separate displacement drives and associated control elements. The construction of the undercarriage of the tool support frame in the form of a free steering axle with its centre of rotation at the point where the tool support frame and the main machine frame are connected has distinct advantages over a tool support frame guided separately on the track by two undercarriages spaced apart from one another.Thus, a direct driving connection is established with the main machine frame coupled with a free choice of the turning radius of the steering axle, i.e. its distance from its centre of rotation formed by the connecting link of the tool support frame, which is the determining factor so far as behaviour around curved sections of track is concerned.At the same time, the fact that the tool support frame carrying the relatively heavy weight of the tamping units is supported on the track provides for a considerable reduction in the weight and operational forces acting on the main machine frame through the connecting link by comparison with conventional tamping machines in which the tamping units are mounted on the main machine frame, particularly when the distance between this connecting link and the supporting and guiding undercarriage of the tool support frame assumes a fairly considerable value within the structurally imposed limits.Finally, the fact that, according to the invention, the overall weight of the machine is distributed over its main undercarriages and the single-axle or bogie-type steering axle of the tool support frame provides for a reduction in the individual axle loads which is particularly important so far as operation on branch lines having relatively low permitted axle loads is concerned.

One particularly preferred embodiment of the invention is characterised in that, as known per se, the tamping unit is mounted on the tool support frame which is arranged between main undercarriages-spaced apart from one another--of the main machine frame and which is separately guided on the track and designed to move along the track with the main machine frame and comprises tamping tools which are mounted on a tool support vertically adjustable by a drive and which are designed for penetration into the ballast bed, being closable in pairs by squeezing drives and vibratable by vibration drives, and in that the tool support frame is designed to be supported on the one hand on the track by the supporting and guiding undercarriage in the form of a free steering axle and, on the other hand, on the main machine frame via a bearing assembly spaced apart from the supporting and guiding undercarriage in the longitudinal direction of the machine, and in that the tamping unit and a track lifting and lining unit provided with lifting and lining drives are connected together with their drives to the tool support frame to form a single working assembly adjacent the immediately following main undercarriage of the main machine frame.

By virtue of this construction and the combination of all the working units involved in the correction and consolidation of the track to form a common working assembly, the automatic, exact guiding of the tool support frame independently of the main machine frame by the free steering axle benefits all the units arranged on the tool support frame in the sense that it provides a satisfactory lateral centring of their tools, i.e. both the numerous tamping tines of the tamping units designed to penetrate into the ballast bed on the left and right of the associated rail and also the lifting and lining tools of the track lifting and lining unit. In this connection, the design engineer is largely free to select the tooling. Thus, the common working assembly may be formed in particular by already proven types of tamping units for working on plain track and/or on switches and crossings and corresponding track lifting and lining units of proven performance, which saves development costs and reduces maintenance work. Finally, the combination of all the working units to form a single working assembly also has the advantage of providing the machine operator with a clear view of the entire working area including the track correcting and tamping zone.

Another embodiment of the invention is characterised in that, at its front end remote from the supporting and guiding undercarriage, the tool support frame is pivotally mounted for universal movement on the main machine frame. By virtue of this arrangement, the freedom of movement of the tool support frame relative to the main machine frame in directions extending transversely of the longitudinal track axis is obtained in a particularly simple and practical manner.

The longitudinally displaceable arrangement of the tool support frame relative to the main machine frame provides a solution to the problem described in British Patent Spec. 1288283 mentioned above in that it enables the distance between the front main machine undercarriage and the track lifting and lining unit, which is critical to the curvature of the rails, to be varied in dependence upon the particular degree of lift required for the track. On the other hand, this particular feature of the invention establishes the prerequisites for the continuous advance of the machine or rather its main frame and the step-bystep advance of the tool support frame with the tamping units arranged thereon from one tamping position to the next.

In one particularly preferred variant of the invention, the tool support frame is in the form of a centre-pole assembly which, at its rear end adjacent the following main undercarriage and carrying the tamping unit, comprises a single axle in the form of a supporting and guiding flanged wheel and axle assembly and, at its front end supported on or rather pivotally connected to the main machine frame, is in the form of a beam-like longitudinal girder extending longitudinally of the machine. This construction of the working assembly takes into account particularly effectively the functional and constructional requirements of a machine designed in accordance with the present invention.Thus, on the one hand, the construction of the supporting and guiding undercarriage in the form of a normal flanged wheel and axle assembly provides for favourable riding properties and for safe guiding of the tool support frame without any danger of derailment, even in the frog region of switches and crossings, so that high speeds can be maintained without difficulty, even during intransit runs of the machine. On the other hand, the construction of the front part of the tool support frame as a beam-like longitudinal girder creates enough space on both sides thereof for accommodating the lifting drives of the track lifting and lining unit and enables the bearing assembly for the longitudinal girder to be arranged between the lateral girders of the main machine frame. In addition, the pole-like construction of the tool support frame saves weight and material.

In another advantageous embodiment of the invention, the tamping unit is mounted on the tool support frame, preferably in the form of a centrepole assembly, between the flanged wheel and axle assembly and the track lifting and lining unit, the main machine frame comprising a longitudinally extending recess for accommodating the vertical displacement drive of the tamping unit. This embodiment provides for a structurally simple, interengaging arrangement of the tamping unit and main machine frame whilst at the same time allowing the support frame sufficient freedom of movement both longitudinally and also transversely of the machine.

Another advantageous embodiment of the invention is characterised in that the tool frame likewise in the form of a centre-pole assembly of the track lifting and lining unit guided on the track by flanged lining rollers is connected to the tool support frame through the track lifting and lining drives and is pivotally connected at its front beam-like end to the longitudinal girder of the tool support frame.The construction of the track lifting and lining unit as a centre-pole assembly, which has already proved successful in conventional tamping machines, if of particular advantage to a machine constructed in accordance with the invention because, in this way the space available beneath the longitudinal girder of the tool support frame may be used for accommodating the track lifting and lining unit, so that no additional lateral space is required.

In another advantageous variant of the invention, the bearing assembly for the beam-like longitudinal girder of the tool support frame is in the form of a roller guide comprising at least one roller which is mounted for rotation about a horizontal shaft extending transversely of the longitudinal axis of the machine and in which the longitudinal girder is mounted with lateral clearance from the main machine frame and guided for displacement longitudinally of the machine by a displacement drive arranged between the tool support frame and the main machine frame. This very simple construction of the bearing assembly provides for low-friction longitudinal displacement and for adequate lateral freedom of movement of the tool frame relative to the main machine frame.

In another embodiment of the invention, the roller guide comprises two pairs of rollers each consisting of one roller applied to the underneath and another roller applied to the top of the beam like longitudinal girder, the rollers being provided on both sides with guide flanges and being mounted on the main machine frame and the longitudinal interval between the pairs of rollers at least corresponding to the displacement path of the displacement drive. This method of mounting and supporting the tool support frame on the main machine frame is particularly suitable for the transmission of even relatively considerable weight and operational forces, particularly the lifting forces acting on the tool support frame during major track lifting and during the lifting of heavy switch components.

Another advantageous embodiment of the invention is characterised in that the displacement drive is arranged above the track lifting and lining unit at a vertical distance from the plane of the track substantially corresponding to the overall height of the tool support frame, extending longitudinally of the machine, and is pivotally connected for universal movement both to the tool support frame and to the main machine frame. This embodiment is distinguished by the fact that the displacement forces of the longitudinal displacement drive are transmitted to the tool support frame immediately above the longitudinal girder so that the point of support of the longitudinal girder is not subjected to any significant, additional momentary load during the displacement process.

Another embodiment of the invention is characterised in that, for continuous advance of the machine with its main frame and for step-bystep advance of the pole-like tool support frame with the tamping unit from one tamping position to the next, the displacement path of the displacement drive amounts to at least twice the sleeper interval. This ensures that the continuous advance of the machine does not have to be interrrupted even when a tamping operation takes more time than usual, for example on account of the heavily encrusted state of the ballast.By virtue of the ample length of the displacement path, enough time is left in reserve to complete the tamping operation properly, for example in spite of the tamping tools having penetrated twice into the ballast bed, and then to move the tool support frame forwards at high speed to the next tamping position by means of the displacement drive. It is of course necessary on safety grounds to provide limit switches or similar devices which, in the event of prolonged tamping, stop the machine in time when the tool support frame reaches its rear end position. A machine equipped in this way satisfies for the first time all the demands made in practice of an efficient, continuously advancing tamping, levelling and lining machine which is easy to operate and which is suitable for uninterrupted long term operation.The new machine according to the invention is particularly suitable for working on high-speed tracks where an additional stipulation laid down by some railway authorities is that the operating staff should not be subjected to the physical strain of constantly restarting and stopping a machine advancing step-by-step from one tamping position to the next.

The piston movement of the displacement drive in the form of a double-acting hydraulic cylinder-and-piston assembly is best designed to be controlled synchronously and oppositely to the continuous advance of the machine or its main frame by a valve assembly or the like. Various means, some of them known, are available to the design engineer for this hydraulic control of the relative movement between the main machine frame and the tool support frame.

According to the invention, one of these control possibilities is to arrange for the flow of pressure medium during a tamping operation to the displacement drive formed by a hydraulic cylinder-and-piston assembly to be controlled by a distance measuring instrument connected to the valve assembly in dependence upon the advance of the machine. This method of controlling the relative movements between the tool support frame and the main machine frame is distinguished by its particular simplicity and also by the fact that already proven distance measuring instruments may be used in track maintenance machines.

According to the invention, another variant is characterised in that the flow of pressure medium to the displacement drive formed by a hydraulic cylinder-and-piston assembly is designed to be controlled by a measuring element, for example a cable potentiometer, which is connected to the valve assembly and which determines the relative displacement between the tool support frame and the main machine frame. The direct measurement of the relative displacement between the tool support frame and the main machine frame ensures extremely precise control of the displacement drive and, hence, maintenance of the centred position of the tamping units in relation to the particular sleeper below which the ballast is to be tamped throughout the entire tamping operation.

According to the invention, another alternative for the synchronous control of the displacement drive in the opposite direction to the continuous advance of the machine is distinguished by the fact that the valve assembly is connected to an inductive pickup which is arranged on the tool support frame, more particularly at the longitudinal centre of the tamping unit; which cooperates with and can be centred over the rail fastenings, for example screws, and which, in the event of displacement from its central position, releases a control signal to the valve assembly to increase or reduce the flow of pressure medium to the displacement drive formed by a hydraulic cylinder-and-piston assembly, depending on the direction of the displacement. This version of the machine does not require any additional development work either because inductive pickups cooperating with rail fastenings have long been used in track maintenance machines, for example for automatically controlling their advance, and are available in various forms.

In another embodiment of the invention, a measuring wheel designed to determine the actual position of the track and cooperating with a levelling and/or lining reference system of the machine is arranged on the tool support frame between the tamping unit and the track lifting and lining unit, a correcting or calculating element which determines the variable distance of the measuring wheel from the rear end point of the reference system and which is designed to convert the particular measurement according to the distance being associated with said measuring wheel.This embodiment of the invention makes it possible to equip the machine with a standard levelling and/or lining reference system capable of moving with the main machine frame longitudinally of the track and correspondingly to compensate the changes in the distance between the measuring wheel and the rear end point of the reference system arising out of the displacement of the tool support frame relative to the main machine frame and also the resulting changes in the error reduction ratio of the reference system. In this connection, it has proved to be an advantage that the error reduction ratio assumes increasingly more favourable values as the support frame moves nearer the rear main undercarriage of the machine, i.e. during the final phase of the track lifting and lining operation and of the tamping operation by which the final position of the track is determined.

In this particular embodiment of the invention, it has proved to be of particular advantage to connect the correcting or calculating element to the cable potentiometer determining the relative displacement of the tool support frame to the main machine frame. In this way, the variable distance between the measuring wheel and the rear end point of the reference system by which the error reduction ratio is determined may be accurately measured and fed as an operand into the correcting or calculating element.

Finally, another particularly advantageous embodiment of the invention is characterised in that the pole-like tool support frame with the flanged wheel and axle assembly and the immediately preceding tamping unit are arranged in an upwardly recessed longitudinal section of the main machine frame. This construction enables the tool support frame equipped with the working units to be accommodated in a spacesaving manner which, nevertheless, allows it the necessary freedom of movement relative to the main machine frame, and affords the possibility of installing and removing the entire working assembly without interference from any parts of the frame, for example for the purpose of repair or maintenance work. In addition, the machine operator is provided with an uninterrupted view, particularly, in cases where the main machine frame has a two-girder construction.

Several embodiments of the invention are described by way of example in the following with reference to the accompanying drawings, wherein: Figure 1 is a side elevation of a two-sleeper track tamping, levelling and lining machine according to the invention.

Figure 2 is a diagrammatic side elevation of an articulated track tamping, levelling and lining machine according to the invention comprising single sleeper tamping units arranged at intervals from one another along the machine.

Figure 3 is a side elevation of a preferred embodiment of a track tamping, levelling and lining machine according to the invention.

Figure 4 is a diagrammatic plan view of the machine illustrated in Figure 3 with the machine frame shown in part only.

Figure 5 is a diagrammatic side elevation of a variant of a levelling and lining reference system for a machine of the type illustrated in Figures 3 and 4.

Figure 6 is a side elevation of another embodiment of a track tamping, levelling and lining machine according to the invention.

Figure 7 is a plan view of the machine illustrated in Figure 6.

The two-sleeper track tamping, levelling and lining machine 48 shown in Figure 1 comprises a bridge-like main frame 51 designed to travel along the track consisting of rails 4, 5 and sleepers 6.

The working units of the machine are mounted on a tool support frame 54 which is arranged in an upwardly recessed longitudinal section of the main frame and which is supported and guided on the track independently of the main frame by means of a single-axle flanged wheel 53, being pivotally connected to the main frame through a bearing 55 arranged at a distance from the flanged wheel assembly 53 in the longitudinal direction of the machine. The track lifting and lining unit 62 of the machine is arranged at the front end of the tool support frame situated at a distance from the flanged wheel assembly.The track lifting and lining unit which is guided by a flanged lining roller on each rail 4, 5 of the track and which is equipped per rail with two lifting rollers spaced apart from one another, is pivotally connected to the tool support frame on the one hand through the lifting drives 63 arranged above each rail and, on the other hand, through the lateral lining drives 64 extending transversely of the longitudinal axis of the machine.

For each of the rails 4 and 5, the machine comprises a twin-sleeper tamping unit 60 which is arranged for vertical displacement (i.e. lifting and lowering) in a recess in the associated side wall of the tool support frame 54 and which is pivotally connected to a vertical displacement drive 61 which is in turn pivotally connected at its upper end to an upwardly projecting extension of the tool support frame.

By virtue of the fact that the tool support frame is supported and guided on the track independently of the main frame, the working units are able automatically and precisely to follow the vertical and, in particular, lateral profile of the track.

The tool support frame carrying the working units is in the form of a centre-pole assembly which, at its rear end adjacent the rear undercarriage 50, comprises a single-axle flanged wheel assembly 53 and which, at its front end, is in the form of a beam-like longitudinal girder 56 which extends longitudinally of the machine and which is connected to the main frame through a bearing 55.

The fact that the tool support frame is in the form of an elongate centre-pole assembly provides the support frame with considerable freedom of movement, particularly in the lateral direction, relative to the main frame, as required in particular for the tamping of switches.

The bridge-like main frame 51 is guided on the as yet uncorrected track and on the already corrected track by undercarriages 49 and 50, respectively. The arrow 52 indicates the working direction of the machine 48 which is designed to advance in steps or continuously, depending on the purpose for which it is being used. The tool support frame 54 of the machine 48 which is in the form of a centre-pole assembly and which is separately guided on the track by a flanged wheel and axle assembly 53 is mounted via its bearing 55 on the main frame 51 for displacement relative thereto longitudinally of the machine. To this end, the beam-like longitudinal girder 56 has a constant double-T profile cross-section and the bearing 55 is formed by guide rollers 57 which are rotatably mounted on the main frame 51 and on which the longitudinal girder 56 rests through its upper flanges 58.The tool support frame 54 is longitudinally displaced relative to the main frame 51 by an adjustment drive 59 in the form of a hydraulic cylinder-and-piston assembly which is pivotally connected both to the tool support frame 54 and to the main frame 51. The front end position of the tool support frame 54 (in the working direction indicated by the arrow 52) in relation to the main frame 51 is shown in solid lines and the rear end position of the tool support frame in chain lines. For each of the rails 4 and 5, a twin tamping unit 60 for simultaneously tamping the ballast beneath two immediately adjacent sleepers 6 is arranged with an associated vertical adjustment drive 61 on the tool support frame 54.The track lifting and lining unit 62 of the machine is pivotally connected on the one hand to the tool support frame 54 through the lifting and lateral lining drives 63 and 64 and, on the other hand, to the longitudinal girder 56 through a length-adjustable linkage 65.

The machine 48 is equipped with a combined levelling and lining reference system 66 which, in the interests of clarity, is shown merely in the form of a thick line and which is in engagement with the support frame 54 at the point 67. The reference system 66 in the form of a linkage extends between a front feeler member (not shown) guided on the uncorrected track and a rear feeler member (again not shown) guided on the corrected track and moves along the track with the tool support frame 54 independently of the main frame 51. Accordingly, the same distances between and measuring conditions for the elements cooperating with the reference system 66 in determining the actual position of the track and also a constant error reduction ratio are guaranteed for each position of the tool support frame 54 in relation to the main frame 51.

The fact that the tool support frame 54 is longitudinally adjustable relative to the main frame 51 makes it possible on the one hand to adjust a predetermined inter-axle distance adjusted to the required or necessary degree of lift of the track to be corrected-between the flanged wheel and axle assembly 53 and the following undercarriage 50 of the machine.Where the track has to be lifted to a considerable extent, this interaxle distance should be kept as short as possible-corresponding to the chain-like position of the tool support frame-in order to keep the length of track between the front undercarriage 49 and the track lifting and lining unit 62, over which the track is raised from its original level to the prescribed level and at the same time correspondingly deformed, as large as possible for the purpose of avoiding excessive stressing and permanent deformation of the rails by the lifting operation. In the case of tracks which require only minimal lifting or, as is normally the case with high-speed tracks, no lifting at all, the inter-axle distance between the flanged wheel and axle assembly 53 and the following undercarriage 50 may be kept correspondingly longer.

Above all, however, the longitudinal adjustability of the tool support frame 54 relative to the main frame 51 provides for the non-stop, i.e.

continuous advance of the machine 48 and its main frame 51 during tamping work. During tamping, the tool support frame 54 (corresponding to the thick-line illustration) remains stationary with the twin tamping units 60 centred on the two immediately adjacent sleepers 6 below which the ballast is to be tamped, whilst the main frame 51 together with the bearing 55 for the longitudinal girder 56 formed by the guide rollers 57 advances continuously in the direction of the arrow 52. The piston 68 of the adjustment drive 59 is also extended by the same amount.

After the ballast beneath the two sleepers 6 has been consolidated to the required extent, the tamping unit 60 are raised by means of the vertical adjustment drives 61 and, immediately afterwards, pressure is admitted to the adjustment drive 59 in the form of a doubleacting hydraulic cylinder-and-piston assembly so that it moves in the direction indicated by the arrow 69. The tool support frame 54 is then advanced at relatively high speed over a distance corresponding to approximately three sleeper intervals until the tamping units 60 are centred over the next two sleepers 6-lying ahead in the working direction-below which the ballast is to be tamped. The described working cycle is then repeated. The control systems for the described movements will be discussed in detail hereinafter with reference to Figures 3 and 4.

Figure 2 illustrates an articulated track tamping, levelling and lining machine 70 of which the machine frame supported at its ends on undercarriages 71, 72 consists of two main frames 75 and 76 which are pivotally interconnected through a pivot bearing 73 and which are supported on a bogie 74 in the vicinity of the pivot bearing 73. The arrow 77 indicates the working direction of the machine 70. The front main frame 75 with the working units (track lifting and lining unit 78, measuring wheel 79 and tamping unit 80) arranged thereon substantially corresponds to the basic structural concept of a standard single-sleeper track tamping machine. A tool support frame 81 in the form of a centre-pole assembly is connected both pivotally and also for displacement longitudinally of the machine to the rear main frame 76 in the form of an elongated bridge girder.To this end, a roller 83 is mounted at the free end of the longitudinal girder 82 of the tool support frame 81, being supported on a longitudinal guide 84 of the main frame 76. The tool support frame 81 and the main frame 76 are interconnected by a longitudinal displacement drive 85 pivotally connected to both. A track lifting and lining unit 87, a measuring wheel 88 applied firmly to both rails 4 and 5 of the track and a single-sleeper tamping unit 89 for each rail are arranged on the tool support frame 81 guided separately on the track by means of a flanged wheel and axle assembly 86.

The machine 70 is equipped with a levelling reference system which, for each of the rails 4 and 5, consists of a stretched wire 90, which at its front end, is guided by the undercarriage 71 on the as yet uncorrected track, is supported on another feeler member 91 in the vicinity of the pivot bearing 73 and, at its rear end, is guided by the undercarriage 72 on the already corrected track. Measuring sensors 92 and 93 formed for example by rotary potentiometers and connected to the measuring wheels 79 and 88, respectively, cooperate in known manner with stretched wires 90 of the levelling reference system for determining the differences between the actual and prescribed levels of the track in the region of the working units 78, 80 and 87, 89 of the machine 70.

The machine 70 is further equipped with a lateral lining reference system consisting of a stretched wire 94 shown as a dash/two-dot line which extends substantially axially of the track and which stretches from a front feeler member 95 guided on the uncorrected track to a rear feeler member 96 guided on the corrected track.

Measuring sensors (not shown) arranged on the measuring wheels 79 and 88 cooperate with this stretched wire 94 in known manner for determining the differences between the actual and prescribed versines in the region of the working units of the machine. As a genuine combination machine, the machine 70 lends itself to numerous potential applications. Thus, using only the drive units 78 and 80, it may be employed as a single-sleeper tamping machine advancing in steps from one tamping position to the next or, using only the units 87 and 89 and the adjustment drive 85, as a single-sleeper tamping machine with a continuously advancing chassis consisting of the two main frames 75 and 76.In addition, it may be operated on the tandem principle using all the workings units 78, 80 and 87, 89. In this case, the tamping units 80 are first centred over the particular sleeper below which the ballast is to be tamped, after which the tamping units 89 are centred by means of the adjustment drive 85 over the sleeper below which they are to tamp the ballast. In this way, the tamping units 80 and 89 may be used at the same time, even where the sleepers are separated by irregular intervals. This procedure enables the track to be lifted to a fairly considerable overall extent in two successive lifting phases by means of the two track lifting and lining units 78 and 87.

Figures 3 and 4 show one preferred embodiment of a track tamping, levelling and lining 'machine 97 according to the invention. This track tamping, levelling and lining machine 97 comprises a main frame 103 designed to travel along the track consisting of rails 100, 101 and sleepers 102 by means of on-track undercarriages 98, 99. The machine is equipped with an engine 104 which drives the undercarriage 98 and its working direction is indicated by the arrow 105. Two operator's cabins 106, 107 and also the drive and power supply systems 108 are arranged on the main frame 103.The working units of the machine 97 are mounted together on a tool support frame 109 in the form of a centrepole assembly which, at one end, rests on the track through a flanged wheel and axle assembly 110 and, at its other end, is supported by its beam-like longitudinal girder 111 on the main frame 103 via a bearing assembly 112. The bearing assembly 112 is in the form of a roller guide comprising two rollers 114 applied to the underneath and another two rollers 114 applied to the top of the longitudinal girder 111 , these rollers 114 being provided on both sides with guide flanges 11 3 and being mounted for rotation on the main frame 103.A lateral clearance between the longitudinal girder 111 and the guide flanges 113 of the rollers 114 enables the tool support frame 109 to pivot laterally to a limited extent about the bearing assembly 112.

The tool support frame 109 and the main machine frame 103 are pivotally interconnected by an adjustment drive 11 5 in the form of doubleacting hydraulic cylinder-and-piston assembly arranged above the longitudinal girder 111. The track lifting and lining unit 116 of the machine 97 comprises a tool frame 119 in the form of a centre-pole assembly which is guided on the track by flanged lining rollers 11 7 and which is equipped with lifting rollers 11 8 designed to be swung in beneath the railhead, being pivotally connected at its front beam-like end 120 to the longitudinal girder 111 of the tool support frame 109. In addition, the tool frame 119 is pivotally connected to the tool support frame 109 through the lifting drives 121 and lateral lining drives 122 of the track lifting and lining unit 11 6.A tamping unit 124 designed to be raised and lowered by a vertical adjustment drive 123 is arranged on the tool support frame 109 for each of the rails 100 and 101. To accommodate the vertical adjustment drives 123, the main machine frame 103 consisting of two upwardly recessed girders 125 comprises a longitudinally extending recess 126 indicated by chain lines.

The machine 97 is equipped with a levelling reference system which, for each of the rails, comprises a stretched wire 127 of which the front end is guided via a feeler member 128 on the uncorrected track whilst its rear end is guided via a feeler member 129 on the corrected track. A measuring wheel 130 applied firmly to the track is provided between the tamping units 124 and the track lifting and lining unit 116. For each rail, a measuring sensor 131 is formed for example by a rotary potentiometer is connected to the measuring wheel 130, cooperating with the corresponding stretched wire 1 27 of the levelling reference system for determining the difference between the actual and prescribed levels of the track. A lateral lining reference system suitable for the machine 97 will be described in detail with reference to Figure 5.

The machine 97 is provided with various items of additional equipment for automatically controlling the various functions performed during the continuous advance of the machine with its main frame 103 and during the step-by-step advance of the tool support frame 109 with the tamping unit 124 from one tamping position to the next. These additional items of equipment comprise a control unit 132 in the operator's cabin 107 which is connected by a line 133 to the drive and power supply systems 108 and which incorporates a valve assembly 1 34 through which pressure can be admitted via a line 135 to the adjustment drive 11 5 formed by a hydraulic cylinder-and-piston assembly to move it in either direction.In an alternative arrangement, the valve assembly 1 34 may be controlled in dependence upon the advance of the machine by means of three different accessories which, in the interests of completeness, are all shown in Figure 3. One of these accessories is a distance-measuring instrument 136 integrated with the feeler member 129 which, for every unit of distance, for example centimetre, travelled by the machine releases a control pulse to the valve assembly 1 34 which regulates the flow of pressure medium to the right-hand cylinder chamber (in Figure 3) of the adjustment drive 11 5 synchronously and oppositely to the direction of advance of the machine so that the tool support frame 109 with the tamping units 1 24 remains centred relative to the sleeper below which the ballast is to be tamped until the tamping operation is complete.

When the tamping unit 124 is raised, the valve assembly 1 34 is reversed, for example by means of limit switches, pressure is admitted to the lefthand cylinder chamber (Figure 5) of the adjustment drive 11 5 and the tool support frame 109 is moved forwards at high speed until the tamping units 124 are centred over the next sleeper below which the ballast is to be tamped.

When the tamping units 124 are lowered, the distance measuring instrument 1 36 is reset to zero and a new working cycle begins.

The same sequence of movements takes place in cases where a measuring element determining the relative displacement between the tool support frame 109 and the main machine frame 103 is used. In the embodiment illustrated, this measuring element is in the form of a cable potentiometer 137. In this case, the piston movement of the adjustment drive 11 5 is controlled proportionally to the adjusting movement or rather to the output voltagedelivered as an analogue signal---of the cable potentiometer 137.

A third possibility for controlling the valve assembly 134 is to arrange an inductive pickup 139 cooperating with the rail fastenings, for example screws 138, on the tool support frame 109 substantially at the longitudinal centre of the tamping unit 124. This pickup 139 behaves neutrally for as long as it remains centred in relation to the particular rail fastening screw 1 38 or rather to the sleeper below which the ballast is to be tamped. If it moves out of its centred position, the inductive pickup 1 39 releases a control signal to the valve assembly 134, increasing or reducing the flow of pressure medium to the adjustment drive 115 depending on the direction of movement.As in the two previously mentioned cases, therefore, the tamping unit 124 remains centred in relation to the sleeper below which the ballast is to be tamped until the tamping operation is complete.

Finally, it is also possible to hold the tool support frame 109 on the track during the tamping operation by braking the flanged wheel 110 and at the same time releasing pressure from the adjustment drive 115.

As is readily apparent from Figure 3, the distances between the crucial points and, hence, the error reduction ratio of the levelling reference system change during the tamping operation and during the continuous advance of the machine. In the front end position of the tool support frame 109 shown in solid lines, the measuring sensor 131 connected to the measuring wheel 130 is situated at a relatively large distance a from the rear end reference point 1 40 of the stretched wire 127.In relation to the overall length / of the stretched wire 127, therefore, the error reduction ratio amount to a:/. In the rear end position of the tool support frame 109 shown in chain lines, the distance of the measuring sensor 131 from the end reference point 140 decreases to the amount b, resulting in an improved error reduction ratio of b:l. This means that the error reduction ratio assumes an optimal value towards the end of the tamping operation, i.e. when the track is finally in its new, corrected position. However, these changes in distance have to be taken into account for measurement purposes. To this end, the control unit 1 32 is provided with a correcting or calculating element 141 which is connected on the one hand to the measuring sensor 131 by a line 142 and, on the other hand, to the distance measuring instrument 136 or to the cable potentiometer 1 37 and which neutralises the effect of the different distances a to b on the result of levelling.

Figure 5 diagrammatically illustrates a combined levelling and lining reference system 1 43 which is suitable for incorporation for example in a track tamping, levelling and lining machine 97 of the type shown in Figures 3 and 4.

The special aspect of this levelling and lining reference system 143 is that, as indicated by the arrows 144, it is moved step-by-step along the track from one tamping position to the next with the tool support frame 109 carrying the working units independently of the main machine frame.

To this end, the lining reference line is formed by a rod 145 is arranged substantially centrally over the axis of the track and which extends from a front feeler member 146 guided on the uncorrected track to a rear feeler member 147 guided on the corrected track, being connected to the tool support frame 109 through a coupling member 148. This coupling member, which acts for example on the flanged wheel 110 of the tool support frame 109, is designed in such a way that, although it enables the rod 145 to be entrained along the track, it does not interfere with the freedom of movement of the rod transversely of the axis of the track. A stretched wire 149 extending between the feeler members 146 and 147 is provided as the levelling reference line for each of the rails 100 and 101, being situated above the rails.The measuring wheel 130 associated with the tool support frame 109 cooperates with the levelling and lining reference system 143 for determining the vertical and lateral differences between the actual and prescribed positions of the track. To this end, it comprises-for each of the rails 100 and 101-a measuring sensor 1 50 formed for example by a rotary potentiometer which cooperates with the stretched wire 1 49 associated with the particular rail. Another measuring sensor 151 arranged over the middle of the track on the measuring wheel 1 30 cooperates with the rod 145 for determining the differences between the actual and prescribed versines of the track.This levelling and lining reference system 143 is characterised by a constant error reduction ratio c:L so that there is no need for the correcting or calculating element 141.

Figures 6 and 7 show a track tamping, levelling and lining machine 1 52 comprising a main machine frame 1 58 which is designed to travel along the track consisting of rails 155, 156 and sleepers 157 by means of undercarriages 1 53, 1 54 and which is equipped with an engine 1 59 acting on both undercarriages 1 53, 1 54, carrying the drive and power supply systems 1 60 of the machine and also an operator's cabin 1 61.The working direction of the machine 1 52 is indicated by the arrow 1 62. The arrows 1 63 symbolize a step-by-step advance of the main machine frame 1 58. A bearing assembly 164 in the form of a coupling link 1 66 rotatable about a vertical shaft 1 65 is situated at the rear end of the main frame 1 58.A heavy-duty tool support frame 1 67 in the form of a centre-pole assembly with a built-on operator's cabin 1 68 is connected for universal movement and for displacement longitudinally of the machine through this coupling link 1 66. At its rear end remote from the bearing assembly 164, the tool support frame 1 67 is separately supported and guided on the track by a flanged wheel and axle assembly 169.A tamping unit 1 71 designed to be raised and lowered by a vertical adjustment drive 170 is arranged on the tool support frame 1 67 for each of the rails 1 55 and 1 56. In the present case, the beam-like longitudinal girder 172 of the pole-like tool support frame 1 67 consists of a hydraulic cylinder-and-piston assembly which forms the adjustment drive 173 for the longitudinal adjustment of the support frame relative to the main frame 1 58. The piston rod 174 of the adjustment drive 173 is pivotally connected to the coupling link 1 66.

The track lifting and lining unit 1 77 equipped with flanged lining rollers 1 75 and lifting rollers 1 76 is pivotally connected to the tool support frame 1 67 on the one hand through the lifting and lining drives 179 and 180 and, on the other hand, through its beam-like end 1 81.

The machine 1 52 is provided with an optical levelling reference system 182 which, for each of the rails 1 55 and 156, consists of a transmitter, for example an infrared or laser transmitter, 183 guided on the as yet uncorrected track by the front undercarriage 153, of a receiver 1 84 supported on the already corrected track by the flanged wheel and axle assembly 169 and of a shadow board 1 86 which cooperates with the transmitter beam 185 and which is supported by a linkage 1 87 on a measuring wheel 1 88 guided on the track.

The machine 1 52 is further equipped with a lining reference system 189 which, in the present case, is in the form of a linkage 190 of which the front end is connected to a feeler member 191 guided on the uncorrected track and of which the rear end is connected to a feeler member 1 92 guided on the already corrected track, in either case over the middle of the track.The feeler member 192 is connected for entrainment to the tool support frame 1 67 through a parallelogram guide 1 93. A measuring sensor 1 94 formed for example by a rotary potentiometer is connected to the measuring wheel 188 and to the linkage 187, cooperating in known manner through one fork arm 1 95 with the linkage 190 of the lining reference system 189 for determining the difference between the prescribed and actual versine of the track in the region of the track lifting and lining unit 177.

Figure 7 clearly shows how the tool support frame 1 67 and the working units connected thereto automatically follow and are adjusted to the longitudinal profile of the track. The support frame 1 67 follows the curvature of the track independently of the main machine frame 1 58 so that the tools of the tamping units 1 71 and of the track lifting and lining unit 1 77 are always in the correct lateral position relative to the associated rail 155 or 156.

The machine 1 52 may be operated in four different modes. In the first, mode, it may be operated as a normal track tamping machine with the adjustment drive 1 73 blocked and with the main frame 1 58 and also the tool support frame 167 advancing in steps from one tamping position to the next, as indicated by the arrows 1 63 and 1 96. In the second mode of operation, the main frame 158 may advance continuously as indicated by the arrow 1 62 whilst the tool support frame 1 67 advances in steps as indicated by the arrows 196. In this case, it would be necessary to use one of the already described arrangement for controlling the adjustment drive 173. In a third mode, the machine 1 52 may be operated as a normal tamping machine for tamping work where the track has to be lifted to a fairly considerable extent, in which case the distance between the rear undercarriage 1 54 and the flanged wheel and the axle assembly 169 of the machine 1 52 is increased by corresponding extension of the piston rod 1 74 of the adjustment drive 173. The fourth mode of operation applies to in-transit runs of the machine for which the inter-axle distances have to be reduced to enable curves to be safely negotiated. This is done by completely retracting the piston rod 1 94 of the adjustment drive 173.

Claims

1. A travelling track tamping, levelling, and lining machine, comprising a main machine frame supported on longitudinally spaced undercarriages, a tool support frame disposed between two longitudinally spaced undercarriages of the main machine frame, the tool support frame being provided with a single undercarriage for supporting the tool support frame on the track, and being coupled in articulated manner to the main machine frame at a position longitudinally spaced from the said single undercarriage, the coupling between the said frames being such that the tool support frame can be moved longitudinally relative to the main frame, a drive for effecting such movement, at least one tamping unit carried by the tool support frame directly forward of the said single undercarriage, and a lifting and lining unit forward of the tamping unit together with lifting and lining drives.

2. A machine as claimed in claim 1, characterised in that the tool support frame is in the form of a centre-pole assembly which, at its rear end adjacent the following main undercarriage and carrying the tamping unit comprises a single axle in the form of a supporting and guiding flanged wheel and axle assembly and, at its front end supported on or pivotally connected to the main machine frame, is in the form of a beam-like longitudinal girder extending longitudinally of the machine.

3. A machine as claimed in claim 1 or 2, characterised in that the main machine frame comprises a longitudinally extending recess for accommodating the vertical adjustment drive of the tamping unit which is mounted to move longitudinally with the tool support frame relative to the main machine frame.

4. A machine as claimed in claim 2 or 3, characterised in that a tool frame, in the form of a centre-pole assembly, of the track lifting and lining unit is guided on the track by flanged lining rollers and is connected to the aforesaid tool support frame through the track lifting and lining drives and is pivotally connected at its front beam-like end to the longitudinal girder of the tool support frame.

5. A machine as claimed in any of claims 1 to 4, characterised in that the bearing assembly for the beam-like longitudinal girder of the tool support frame is in the form of a roller guide comprising at least one roller which is mounted for rotation about a horizontal shaft extending transversely of the longitudinal axis of the machine and in which the longitudinal grider is mounted with lateral clearance from the main machine frame and guided for displacement longitudinally of the machine by an adjustment drive arranged between the tool support frame and the main machine frame.

6. A machine as claimed in claim 5, characterised in that the roller guide comprises two pairs of rollers each consisting of one roller applied to the underneath and another roller applied to the top of the beam-like longitudinal girder, the rollers being provided on both sides with guide flanges and being mounted on the main machine frame and the longitudinal interval between the pairs of rollers at least corresponding to the displacement path of the displacement drive.

7. A machine as claimed in any of claims 1 to 6, characterised in that the adjustment drive is arranged above the track lifting and lining unit at a vertical distance from the plane of the track substantially corresponding to the overall height of the tool support frame, extending longitudinally of the machine, and is pivotally connected for universal movement both to the tool support frame and to the main machine frame.

8. A machine as claimed in any of claims 1 to 7, characterised in that, for continuous advance of the machine with its main frame and step-by-step advance of the pole-like tool support frame with the tamping unit from one tamping position to the next, the displacement path of the longitudinal adjustment drive amounts to at least twice the sleeper interval.

9. A machine as claimed in claim 8, characterised in that the piston movement of the longitudinal adjustment drive, in the form of a double-acting hydraulic cylinder-and-piston assembly, is designed to be controlled synchronously and oppositely to the continuous advance of the machine of its main frame by a valve assembly or the like.

10. A machine as claimed in claim 9, characterised in that during a tamping operation the flow of pressure medium to the said hydraulic cylinder-and-piston assembly is designed to be controlled by a distance measuring instrument connected to the valve assembly in dependence upon the advance of the machine.

11. A machine as claimed in claim 10, characterised in that the flow of pressure medium to the said hydraulic cylinder-and-piston assembly is designed to be controlled by a measuring element, for example a cable potentiometer, which is connected to the valve assembly and which determines the relative displacement between the tool support frame and the main machine frame.

12. A machine as claimed in claim 11, characterised in that the valve assembly is connected to an inductive pickup which is arranged on the tool support frame, more particularly at the longitudinal centre of the tamping unit; which cooperates with and can be centred over the rail fastenings, for example screws, and which, in the event of displacement from its central position, release a control signal to the valve assembly to increase or reduce the flow of pressure medium to the said hydraulic cylinder-and-piston assembly, depending upon the direction of the displacement.

13. A machine as claimed in any of claims 1 to 12, characterised in that a measuring wheel designed to determine the actual position of the track and cooperating with a levelling and/or lining reference system of the machine is arranged on the tool support frame between the tamping unit and the track lifting and lining unit, a correcting or calculating element which determines the variable distance of the measuring wheel from the rear end point of the reference system and which is designed to convert the particular measurement according to that distance being associated with said measuring wheel.

14. A machine as claimed in claim 11 and 13, characterised in that the correcting or calculating element is connected to the able potentiometer determining the relative displacement of the tool support frame to the main machine frame.

1 5. A machine as claimed in any of claims 2 to 14, characterised in that the pole-like tool support frame with the flanged wheel and axle assembly and the immediately preceding tamping unit are arranged in an upwardly recessed longitudinal section of the main machine frame.

16. A travelling railway track tamping machine substantially as herein described with reference to Figure 1, Figure 2, Figures 3 to 5, or Figures 6 and 7 of the accompanying drawings.