US3888052A - Relating to methods for grinding rails - Google Patents

Abstract

Method for grinding rails by means of a rail-borne vehicle, a frame movably supported on the vehicle, and at least one grinding unit adjustably mounted on the frame and arranged to provide at least one rail grinding zone. A rail follower is mounted on the frame substantially in line with the grinding zone, and the grinding unit is so supported that at least the grinding zone is adjustable transversely of the rail direction. At least one of the grinding zone and rail follower is locatable at different selected longitudinal spacings. The follower includes at least two points which contact the rail and by adjusting the grinding zone relative to the two point contact afforded by the follower, an optimum grinding position can be obtained dependent on the irregularities of the rail to be trued.

Description

United States Patent Panetti June 10, 1975 [54] RELATING TO METHODS FOR GRINDING 3,738,066 6/1973 51/178 RAILS FOREIGN PATENTS OR APPLICATIONS Inventor: Romolo Pflnetli, e a, 1,231,751 4/1960 France 51/178 Switzerland [731 Assignees: Speno International S.A., Geneva, Primary Emminef--lames 101165.

Switzerland; F k speno R il d Attorney, Agenl, 0r FirmWaters, Schwartz & Nissen Ballast Cleaning Co., Inc., lthaca, NY. [57] ABSTRACT [22] Filed: June 7, 1973 Method for grinding rails by means of a rail-borne ve- [ZI] Appl No 367 875 hicle, a frame movably supported on the vehicle, and at least one grinding unit adjustably mounted on the frame and arranged to provide at least one rail grind- [30] Foreign Application Priorlty Data ing zone. A rail follower is mounted on the frame sub- June a, 1972 Switzerland 08498/72 stantially in lin ith the grinding zon and the grinding unit is so supported that at least the grinding zone [52] US. Cl. 51/281 R; 51/178 is adjustable transversely of the rail direction. At least [51] Int. Cl B24b 1/00 one of the grinding zone and rail follower is locatable [58] Field of Search 51/281 R, 178 at difi'erent selected longitudinal spacings. The follower includes at least two points which contact the [56] References Cited rail and by adjusting the grinding zone relative to the UNITED STATES PATENTS [W0 point contact afforded by the follower, an Optimum grinding position can be obtained dependent on 13331333 351333 12??" "1111111?1111111111'111111111"51i541 S the trregtttertttee ef the ttt be treet- 3,358,406 l2ll967 Speno et al 5l/l73 8 Claims, 1 Drawing Figures 3,509,667 5/1970 Llndmark 5l/l78 I l ,15 l 1s\ 26 31. r t n 1 1!. l

(,2 x 3 i e i A C A 7 1 1 g 1 -14 v t t 1 J PATENTEDJUH 10 ms SHEET Fig. 3

Fig 2 1 RELATING TO METHODS FOR GRINDING RAILS BACKGROUND 1. Field of the Invention This invention relates to methods for grinding rails.

2. Prior Art It is known that with more concentrated and rapid train traffic with increased axle loads. accelerated wear of the rail bearing surfaces is caused, particularly on curves and in braking zones. Cold rolling. combined with the wearing away of metal particles, causes irregularities in the bearing surface of a rail. which tend to become more and more aggravated with continued use.

To eliminate this as quickly as possible, rotary grinders are used which operate either at their periphery (a substantially cylindrical working surface) or by an end face; in the latter case the grinder is usually formed with a central recess and may have one or two grinding zones. depending on its relationship to the rail.

It is of paramount importance not only to avoid accidental notches in the rail. but also to obtain high precision. of the order of a few hundredths of a millimeter.

For this purpose there have been proposed a number of variants of a rigid frame fitted with a grinder fixed between wheels or slides forming rail tracers or followers. generally at the mid-point therebetween. Means for movement in the transverse direction of the frame make it possible to adjust the grinder and the tracers relative to one another. The frame is then moved along the rail by various means. which ensure transverse balance.

Machines of this type are adapted for truing the upper and/or inner surface of the rail head. Almost all these machines currently employ a grinder that can be inclined across the rail to adapt itself to the curvilinear section of the bearing surface.

In high performance machines, several grinders are arranged along the same frame, and they can all be adjusted transversely thereto. It then becomes possible to eliminate the tracers. as the grinders in sufficient number guide each other. In this category, there are machines in which the grinders on the same frame are able to slide transversely through the action of a fluid under pressure which apportions in different ways the bearing force of each grinder against the rail. In this case the hydraulic or oleo-pneumatic association of the grinders also enables the tracers to be eliminated.

High performance machines as a rule have one or more of such frames per length of rail. These are mov able in relation to the fixed frame of the vehicle that carries them so that they operate as stated. means (generally hydraulic) ensuring the necessary pressure for grinding and. at the end of the work. the lifting of the mobile frames.

The use of such frames, with single or multiple grinders with or without rail tracers, displays a common defeet which has often been noted: the passage of the grinders leaves unaffected, or sometimes even causes, residual waviness along the bearing surface. which is incompatible with present railway requirements.

This fault is due to the fact that the distances between the points of contact of the grinders-or tracers correspond to the wavelength (or certain fractions or multiples thereof) of the produced undulations. The tools then tend to follow these undulations and even amplify them through the effect of resonance. In the known machines. the grinders or tracers are at fixed distances apart on the frame. and it is impossible in operation to do away with this coincidence of periodicity.

Moreover, the use of sets of grinders of the type described comes up against additional difficulties owing to their length and the variable curvature of the rail in the vertical and/or horizontal sense.

These two types of defect are also apparent when the grinders have different transverse inclinations.

SUMMARY OF THE INVENTION An object of the present invention is to avoid the serious drawbacks mentioned and to improve the precision and efficiency of high performance rail grinding machines.

According to one aspect of the present invention there is provided a method of truing a rail by grinding. wherein the locus of a reference base is defined by two point contact with the rail and grinding means are adjustably mounted on the base to co-operate with the rail at at least one grinding zone in line with said two points, and wherein the grinding means are adjusted to shift at least said one grinding zone longitudinally of the two point line to an optimum position dependent on the irregularities of the rail to be trued.

For effecting the method of the present invention there is provided apparatus, comprising a frame to be carried by a rail-borne vehicle and movable relative thereto, at least one grinding unit adjustably mounted on said frame and arranged to provide at least one rail grinding zone. and rail following means mounted on said frame and substantially in line with said at least one grinding zone, at least one grinding zone being adjustable transversely to the rail direction and at least one pair of grinding zones and rail following means being locatable at different selected longitudinal spacings.

For a better understanding of the invention some constructional forms thereof will now be described. by way of example. with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a rail grinding machine according to the invention seen from outside the track;

FIG. 2 is an end view corresponding to a section on line I-I of FIG. 1;

FIG. 3 is a plan view corresponding to a section on line IIII of FIG. 1;

FIG. 4 is an explanatory diagram showing three grinders in side view;

FIG. 5 is a detail of a modification applicable to the machine of FIGS. 1 to 4 and corresponds to part of FIG. 1;

FIG. 5a is a diagrammatic side view of another modification;

FIG. 6 is an end elevation transverse to the rail. showing another grinding machine truing the inner surface of the rail head;

FIG. 7 is a section taken on line VII-VII of FIG. 6', and

FIGS. 8, 9 and 10 are explanatory diagrams showing the working of three different grinding machines.

DETAILED DESCRIPTION In FIGS. 1 to 3 there is seen a rail 1, which is assumed to be horizontal for ease of explanation. said rail supporting the flanged wheels 2, 3 of a two-axle vehicle,

3 whose fixed frame is represented by a vertical plate 4. The plate 4 is located directly above the rails and is in the shape of an inverted U to hold between its uprights a moving frame carrying grinding units.

This moving frame consists of a horizontal rectangular structure with two stringers 5,6, the stringer 5 being inside the rail whereas the stringer 6 is outside the rail. said stringers being welded to cross-pieces 7,8. The lat ter are centrally drilled and receive coaxial pivots 9 and 10, which are normally locked to the cross-pieces by screws 1] and 12 respectively. These pivots include parts projecting outwardly of the moving frame and formed as slides or shoes 13 and 14 which are grooved at their ends. These grooves guide the frame for vertical movement on the uprights of the plate 4, while preventing it from rockingv Sufficient play is provided at the bottom of the grooves to allow a slight longitudinal slant of the movable frame structure.

Two vertical hydraulic jacks l5, 16 are pivotally connected at 17 and 18 to the fixed frame 4 and at 19 and 20 to the slides 13 and 14 respectively of the moving frame.

In this embodiment. three rotary grinders 21, 22 and 23 with vertical axes are provided, each being fitted to a grinding unit of identical construction. For simplicity of explanation only one grinder 22 will be described.

The grinder 22 is mounted at the end ofa shaft 24 of a motor whose casing 25 is extended by a tube 26 that houses the greater part of the shaft 24. This tube is provided with two transverse coaxial journals 27 and 28 which respectively pivot in the middle of generally T- shaped plates 29 and 30 mounted transversely between the stringers S and 6.

Along the top of the inner stringer 5 there is formed a groove 31 extending in the longitudinal direction and in which fits the rounded ends of bolts 32 and 33 which pass through the corresponding upper inner flanges of the plates 29 and 30 respectively. The plates are also carried by the other stringer 6 through bolts 34 and 35 which pass through the upper outer flanges, while the lower flanges of the plates are fitted with clamping bolts 36, 37, 38 and 39 arranged to engage the undersides of the stringers. The journals 27 and 28 can be locked by bolts 40 and 4!.

The operation of the grinding apparatus described is as follows:

The moving frame 5, 6, 7 and 8, guided by the uprights of the plate 4, is lowered by the jacks 15 and 16 to a desired horizontal position indicated by scales 42, 43 on the uprights. Then each of the grinding units is adjusted as described below for horizontal grinding of the rail.

The four lower clamping bolts 36, 37, 38 and 39 are loosened. as are the locking bolts 40 and 41 ofthe jour rials, while the grinding unit is held upright. By rotating the guide bolts 32 and 33, and then the supporting bolts 34 and 35, the plates 29 and 30 are brought in pairs to the same level. The journals 27 and 28 which they support thus being horizontal, the undersurface of the grinder is parallel to a generating line of the rail. Next, the motor is moved into exact vertical position by pivoting on the journals 27 and 28, which are then locked by the bolts 40 and 4]. It will be seen that the plates 29 and 30 constitute a support which, through the almost simultaneous operation of the four bolts 32, 33, 34 and 35 makes it possible to adjust the undersurface of the grinder to be level with the rail. After this adjustment,

the four lower bolts 36, 37, 38 and 39 are clamped against the stringers 5 and 6.

The three grinders are thus adjusted in turn. after which the motors are started and the jacks are actuated to apply the pressure required for grinding as the vehicle is set in motion.

Since, in accordance with usual practice, these upright grinders are recessed towards their center, it will be observed that the set of three rotary grinders produces six grinding zones spaced from one another in the longitudinal direction of the frame, In this embodiment, these zones are in the same plane. The passage of this grinding apparatus makes it possible to eliminate slight irregularities due to wear of the bearing surface of the rail, but in some circumstances more or less regular longitudinal undulations of various wavelengths will remain after grinding, or will even be aggravated by the apparatus.

Consider first of all the simple case where, as illustrated in FIG. 1, the six contact zones on the rail are spaced regularly at a distance which coincides with the wavelength of an already existing corrugation, represented by broken lines in FIG. 1 with greatly exaggerated differences of level. It will be seen that the grinding apparatus will tend to follow this corrugation, especially since the length of the zones of effective grinding will be shorter than normal.

When, as illustrated diagrammatically in FIG. 4, the wavelength of a corrugation is twice the previous one, i.e. equal to the distance between the axes of adjacent grinders, for the most part only three alternate ones out of the six grinding zones will be in use at any one time, which also accentuates the fault.

If, on the other hand, the corrugation found is shorter, experience shows that a similar drawback can arise, albeit greatly attenuated by the relative width of the grinding zones. lt nevertheless shows that the problem of coincidence of periodicity can be maintained, or even amplified, by the grinding apparatus itself. Other factors, such as grinder wear, must be taken into account when setting up as they can affect the performance.

With the apparatus described, a set of grinders can be readily adapted to cope better with the conditions found in operation by modifying the spacing of the contact zones. To do this, it suffices to loosen the four lower bolts 36, 37, 38 and 39 and move the grinder unit 22, for example, along the movable frame with its support plates guided by the bolts 32 and 33 engaging in the longitudinal groove 31. It is possible to prevent the grinder from remaining in contact with the rail during this movement by slightly pivoting the unit on the rounded ends of the guide bolts 32, 33.

The new position will be automatically correct, i.e. parallel to the previous one, since none of the upper bolts of the support will have been turned. The lower bolts are then retightened.

From what has already been said, it should be clear that such modification of the spacing of the grinding zones can, by eliminating the coincidence of periodicity mentioned, do away with troublesome residual corrugations.

According to the conditions found, usually only a slight change in the relative positions of the grinders of a group will suffice for good results. At least one of the grinding units may therefore be infinitely or continuously adjustable over a given length of the movable frame and marks may be made on the frame to aid in positioning.

Nevertheless, observation of worn rails shows that. depending on the type of construction of the track. certain categories of longitudinal corrugations are frequently repeated. It is then possible and sufficient to provide discontinuous or stepwise adjustment along the frame for at least one of the grinding units. For this purpose. the frame is provided. after tests to determine what spacings are best, with detent means for at least one unit. These are shown as notches 44 in FIG. I and in a selected notch there is inserted the lower bolt 38 of the associated unit. These detent means can. of course. be provided in many different forms, for instance as projections on the stringer 6, or in the form of a series of holes. They could also be provided on one of the support plates of the grinding unit. as shown in FIG. 5, where a pawl pivoted on the stringer 6 can engage in notches made in a plate 46 screwed to the plate 29. The latter and the stringer could alternatively be drilled to receive a removable peg inserted in two registering holes. These examples are of course by no means restrictive.

It may also be an advantage to be able to combine continuous, infinite adjustment with intermittent stepwise adjustment. In the arrangement of FIG. 5, the plate 46 has two elongated holes or slots through which its securing screws 47 extend. The plate 46 can be infinitely adjusted longitudinally by the length of these slots by loosening the screws 47 and retightening them after moving the plate. The coarse adjustment is made in steps furnished by the notches of the plate 46, and the fine adjustment is made by sliding the plate 46 relative to the support plate 29.

It is also possible selectively to couple grinders for simultaneous longitudinal movement. In FIG. 5, a bar 47a is screwed to and connects the support plates 29 of the two end grinding units so that their simultaneous movement alters the distance between both pairs of neighboring grinders. lt is still possible to move the end grinders separately if the linking bar is removed and to secure them in their independent positions by their clamping bolts. The extremity of the bar 470 has several holes for the screw to the plate 29 to pass through, which allows additional adjustment.

To assist truing, which is frequently done by passing to and fro along the same section of track, it is a particular advantage to distribute the grinders symmetrically in relation to the middle of the length of the frame. A single adjustment can then suffice, and marks may again be provided on the frame by which to check the positions. FIG. 5a which is a diagrammatic detail of FIG. I, shows that for this purpose it is convenient to use a rule 47)) graduated similarly in opposite directions from its center. To avoid mistakes, there is provided an aid-to-positioning mechanism in the form of an endless cable 470 traversing two pulleys 47d and 47e rotatably mounted at opposite ends of the stringer 6. The cable is provided with two indexes 47f. 47g that co-operate with the rule and with which pointers on respective support plates 29 are brought into registry. As the cable is moved. the indexes move the same amount towards or away from the center. in a modification (not shown) the cable is fixed to the support plates at the re spective index points so as positively to synchronize their movements.

It is possible. if necessary. to assist the longitudinal shifting of one or more grinding units by known methods, such as rollers, jacks or motors.

FIG. 6 shows, applied to one of the lateral faces of a rail 1, a grinder 22' mounted at the end of a horizontal shaft 24' of a motor whose casing 25' is extended by a tube 48 that houses most of the shaft. The middle of the tube 48 is expanded to form a piston 49 against which bears a spring 50. The piston 49 can slide in a cylinder 51 but is held against rotation by a pin 52 engaging in a groove 53 of the tube. Fluid under pressure delivered by a pipe 54 to the chamber 55 opposite the spring applies the grinder against the rail with the pressure required for grinding.

At the top of the cylinder 51 there is fixed a vertical pivot 56, lockable by a screw 57 to a horizontal arm 58. The latter is itself lockable in set angular positions by a screw or bolt 59 to the bottom of a vertical shaft 60 provided with two diametrically opposite transverse journals 27' and 28'.

Three of these assemblies can be installed on the movable frame 5, 6, 7, and 8 and support plates 29 and 30 in place of as many rotary grinders with vertical axes, their journals 27' and 28 taking the place of the previous ones 27 and 28.

Setting up and operation are similar to the first described embodiment.

In FIG. 7, which is a horizontal section on the line I"- ll] of FIG. 6, one of the assemblies that has just been described is arranged for truing the upper part of the rail bearing surface. The piston can be locked, for instance at the end of the stroke, by hydraulic pressure.

Operation is similar to that of the first embodiment, but the three grinders only provide three zones of contact with the rail.

It will be noted that longitudinal adjustment of the contact zones can also be obtained by appropriate rotations of the arm 58 and the casing 25' of a grinding unit.

It will also be observed that these grinders with horizontal axes may, like the previous ones, incline across the frame, which can itself slope transversely thanks to the pivots 9 and 10 of FIG. 1.

The grinding machines described furnish a further very important advantage: when an end grinder, for instance 21, is shifted, the distance between the extreme contact zones is altered, which allows the machine to be readily adapted to the various curvatures of the rail. such as are found on curves and changes of incline, i.e. at places where truing is needed very often.

By correlating the total length between extreme zones to the distance between adjacent pairs of grinders, it is also possible to do away with undesirable residual corrugations.

in the case of very sharp bends of the rail, the end grinders are raised, or else they are inclined, as described above, which modifies the distribution of the possible contact zones along the frame.

On a straight track it is preferable, from the point of view of precision and speed of work, to true with more than three grinders per frame, this number not being restrictive. The grinders may be carried by various types of vehicle, and there may be two or more mobile frames mounted between or beyond the axles.

Referring back to FIG. 1, it it is assumed that the motor of one or each extreme grinder has stopped, the latter would serve as a guide for the grinders still in operation. However, if such guide means are required, the end grinders can be replaced by sliding shoes or rollers, forming rail tracers. It should be remembered that these tracers are subject to considerable wear owing to the abrasive powder used in grinding.

FIGS. 8 to are diagrams intended to show various modes of operation.

FIG. 8 illustrates a rotary grinder with a horizontal axis, acting in conjunction with two tracers, one leading, the other trailing, all being mounted on a frame forming a reference base.

In the direction of travel, denoted by the arrow. the point A of contact of the leading tracer is on a rough section (greatly exaggerated in the illusration) of the rail, while point B of the rear tracer is on the part already trued by the grinder, which is at zone 1A. it will be seen that it is desirable to have the grinder set back along the base frame towards the rear tracer to lessen the influence of the roughnesses found and to improve precision. Travel in the opposite direction would then require the grinder to be shifted towards A.

If the distance between tracers is reduced, any local curvature will be little effected by the grinding while if this distance is lengthened, grinding tends to eliminate the curvature.

For truing with alternating travel, the grinder is advantageously placed half-way between the tracers, which are themselves spaced to take account of the irregularities to be trued.

FIG. 9 illustrates the case of a tracer guiding a grinder with a vertical axis and therefore having two grinding zones, each supplying the other with a second tracing point. Again, the distance between tracer and grinder is selected according to the conditions expected.

FIG. 10 shows a symmetrical distribution of grinders with vertical axes, it being possible to adjust the length between extreme grinders to the curvature of the rail, and the distances between adjacent grinders to the irregularities of the bearing surface.

It has been assumed above that the support(s) for the grinders or tracers was/were locked during grinding. It is also possible, however, to modify one or more of the longitudinal spacings as work progresses. For this purpose, the motor mentioned above as a possibility for moving the grinding units may drive a device such as the cable of FIG. 5a, the cable being secured to one or more units. The clamping of the plates 29 and 30 will not be absolute in that case.

It is also possible, by appropriate regulation, to govern speed of travel in a particular manner, for instance it may be kept constant or be made sinusoidally varying. Reciprocating movements, i.e. cyclic movements, are particularly advantageous for improving the truing precision.

It is emphasized that modification on the track of the longitudinal spacing of the grinders or tracers can be carried out when the grinders are rotating or are stationary; and either when the vehicle has stopped or is in operation. It may be done before, after or during the operation of setting up the grinders at the correct level and angle.

What is claimed is:

l. A method of truing a rail by grinding comprising mounting a reference base by two point contact with a rail to be ground, adjustably mounting a plurality of spaced grinders on the base to co-operate with the rail at respective grinding zones in line with said two points, and adjusting the longitudinal spacing between the grinders to shift said grinding zones longitudinally of the two point line to an optimum position dependent on the irregularities of the rail to be trued.

2. A method as claimed in claim I comprising effecting grinding by passing the grinder to and fro on the rail.

3. A method as claimed in claim 1, wherein the adjustment is made before effecting a run with the grinders, and fixing the grinders at said optimum position.

4. A method as claimed in claim 1, wherein the adjustments are made during a run with the grinders on the rail in accordance with the shape of the rail.

5. A method as claimed in claim 1, wherein adjustments are made during a run with the grinders on the rail as a function of time.

6. A method as claimed in claim 1, wherein adjustments are made in accordance with a predetermined cycle.

7. A method as claimed in claim 1, wherein for curved rails, the two points of contact and said grind zone are spaced apart to provide a maximum spacing between endmost regions dependent on the curve.

8. A method as claimed in claim 1, wherein the grinding zones are maintained symmetrically with respect to the mid-point between said two contact points.

Claims (8)

1. A method of truing a rail by grinding comprising mounting a reference base by two point contact with a rail to be ground, adjustably mounting a plurality of spaced grinders on the base to co-operate with the rail at respective grinding zones in line with said two points, and adjusting the longitudinal spacing between the grinders to shift said grinding zones longitudinally of the two point line to an optimum position dependent on the irregularities of the rail to be trued.

2. A method as claimed in claim 1 comprising effecting grinding by passing the grinder to and fro on the rail.

3. A method as claimed in claim 1, wherein the adjustment is made before effecting a run with the grinders, and fixing the grinders at said optimum position.

4. A method as claimed in claim 1, wherein the adjustments are made during a run with the grinders on the rail in accordance with the shape of the rail.

5. A method as claimed in claim 1, wherein adjustments are made during a run with the grinders on the rail as a function of time.

6. A method as claimed in claim 1, wherein adjustments are made in accordance with a predetermined cycle.

7. A method as claimed in claim 1, wherein for curved rails, the two points of contact and said grind zone are spaced apart to provide a maximum spacing between endmost regions dependent on the curve.

8. A method as claimed in claim 1, wherein the grinding zones are maintained symmetrically with respect to the mid-point between said two contact points.

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