GB2044827A

GB2044827A - Measuring rail corrugations

Info

Publication number: GB2044827A
Application number: GB8001719A
Authority: GB
Original assignee: Loram Maintenance of Way Inc
Current assignee: Loram Maintenance of Way Inc
Priority date: 1979-01-18
Filing date: 1980-01-18
Publication date: 1980-10-22
Also published as: FR2446892A1; DE3000323A1; IT1174658B; IT8019250A0

Abstract

A method and apparatus for determining the extent of corrugations in the surface of a railway track is disclosed. A proximity detector means 71 is disposed intermediate the ends of a skid-like member 21 having a longitudinal dimension in the order of twice the expected crest to crest dimensions of the corrugations to be determined, and supported for longitudinal travel along the length of a rail, in such a manner that the proximity detector means will not contact the rail. As the skid is moved along a rail the proximity detector will sense, or determine, the variations in the top surface of the track, and the output thereof may be used to generate a profile-like record of the condition of the track. <IMAGE>

Description

SPECIFICATION Rail corrugations analyzer This invention relates to a method and apparatus for determining the nature of the corrugations that appear in the upper surface of railway track under certain conditions of operation. The invention is intended to provide a recordable determination that may be used to illustrate a profile along the longitudinal direction of the upper surface of the track so as to enable a determination of the proper time to grind or otherwise service the upper surface of the track to remove the corrugations.

One example of the prior art to which the invention pertains is the Von Beckmann US Patent 3,604,117, which utilizes a light beam and a shadow board together with transmitters and receivers to attempt to measure the nature of the upper surface of a track. There are other examples of mechanical systems which attempt to provide information on the upper surface of a track that are too numerous to mention.

In applying the principles of the invention, both the method and apparatus embody the construction of a longitudinally elongated skid-like member which may be conveniently mounted on a suitable cart adapted to travel over the length of a railroad line. Ideally, a pair of longitudinally skid-like members are provided and are suspended from the cart so as to come in contact with the upper surfaces of the parallel rails and are configured to contact the files by the use of sliders, plates or the like. The longitudinal dimensions of the skid-like members are determined to be approximately twice the expected crest to crest extent of the corrugations in a particular railroad system.A non-contacting form of proximity sensing element is disposed near the center of each of the skid-like members to measure the distance to the upper surface of the track as the cart is moved along the track system. One form of a proximity determining device is an addy current type of impedance transducer that has an output signal proportional to the proximity of a metallic surface.

Another form of proximity determining device may utilize, for example, the variations in back pressure in a stream of air directed against the surface, the profile of which is to be determined.

In any event, the method and apparatus involves the permanent recording of the signals representing the longitudinal profile of tracks in a system that may easily be correlated to the relative location of the elements constituting the track profile.

Other objects and advantages of the invention will become apparent from a consideration of the appended specification, claims and drawings in which: Figure 1 is a top plan view of the invention shown embodied in a cart to be drawn over a railroad track system; Figure 2 is a side elevation view of the embodiment of Fig. 1; Figure 3 is an enlarged, fragmentary sectional view taken along section line 3-3 on Fig. 1; Figure 4 is a front elevational view of the embodiment of Fig. 1; and Figure 5 is a diagrammatic-schematic view of the track profile measuring apparatus.

Referring now to Figs. 1, 2, 3 and 4, the invention is shown embodied in a cart 10 having a T-shaped frame, a pair of railroad track wheels 1 2 and 1 3 at the extremities of the lateral portion of the frame (shown in operative position on tracks 1 5 and 16, respectively); and a draw bar comprised of the longitudinally extending portion of the Tshaped frame that has, at its front end, suitable apparatus for connection to a source of motive power, such as a small motorized cart adapted to travel over a railroad system.

A pair of skid-like members 20 and 21, suitably configured (as will be described below) to travel over the rails of a railway system, are shown suspended from the draw bar 1 4 on cart 1 0. Skid 20 is provided with vertical guide plates 22 at each end and lateral guide plates 24 adjacent each end in proximity to a suspension plate 26 disposed near each of said ends and having a body 28 and a wear member 30 disposed on the bottom surface of said body. Similarly, skid 21 has vertical guide plates 23 and lateral guide plates 25 in proximity to each end as well as suspension plates 27 near each end, a body 29 and a wear member 31, adapted to engage the top surface of a rail.The longitudinal length of skid members 20 and 21 is approximately equal to twice the normal crest to crest length of corrugations encountered in a particular railroad track system. In one system, this was determined to be approximately 76 cm and therefore the length of skid members 20 and 21 would be approximately 152 cm. It may be noted that the wear means 30 and 31 may be comprised of suitable metallic substance, such as stellite, or any suitable metallic or plastic composition. The wear means are shown attached to the bottom of skid members 20 and 21 by use of suitable fastening means, e.g., bolts. Skid members 20 and 21 are suspended from draw bar 14 of cart 10 through the use of four suspension assemblies and only two of these will be described in detail since the operation of the others will be readily apparent from a consideration of the following description.Left skid suspension means 40 is shown including a top longitudinally extending member 42, a vertical arm 44, a bottom longitudinal member 46, a transverse front member 48, a transverse rear member 50, a top transverse horizontal arm 52, a rod 54, a mounting 56, a compressional spring 58 and skid mounting plate 60.

Similarly, right suspension 40 includes a top longitudinal member 43, a vertical arm 45, a bottom longitudinal member 47, a transverse front member 49, a transverse rear member 51, a top transverse horizontal arm 53, a rod 55, a mounting 57, a compressional spring 59, and suspension plate 61.

It should be noted that members 44 and 52 and 45 and 53 are rigidly connected together to form a bell crank journal for rotation about the junction of the two members thereof. The transverse top horizontal members are connected to the rod members 54 and 55 and extend through mountings 56 and 57 so that compressional springs 58 and 59 may exert a force on the top inside ends of members 52 and 53 to cause the lower ends of the suspensions to move in an outward direction with respect to the tracks upon which the cart is disposed. This causes the lateral guide plates to engage the side of the rails as may best be seen in the front view of Fig. 4.Suspension plates 60 and 61 are disposed on the outer ends of members 48 and 50 and 49 and 51, respectively, and are connected to suitable apertures through bolt members 62 and 63, respectively, so as to allow for up and down motion of skid 20 and 21, respectively, about the axis of bolts 62 and 63. It should be noted that members 49 and 51 are welded to bottom longitudinal member 43 which is in turn rotatably journaled upon the lower ends of vertical arms 44 and 45. This allows skids 20 and 21 to properly engage the top surface of the rail as the cart is drawn along a track system under their own weight and the lower part of the suspensions so as to allow vertical movement about the horizontal axes of the suspension bolts. The center portion of Fig. 3 shows a representation of a portion of a corrugations as in proximity to sensor 1 7.

The extent of the corrugations over which cart 10 is drawn, is determined by suitable sensors 70 and 71 that determine the vertical distance from the location of the sensor near the mid-points of skids 20 and 21 at a particular point in time. As may be seen in the schematic and diagrammatic illustration of Fig. 5, sensors 70 and 71 are each connected to sensor amplifiers 74 and 75 through conductors 72 and 73, respectively. An output from each of the sensor amplifiers is shown connected to a pair of terminals 88 that are adapted to be connected to a suitable data processing or signal recording apparatus.In other respects, the operation of the measuring and recording portion of my apparatus, in an operative embodiment, consisted of a filter 78 connected to the output of sensor amplifier 74 through conductor 76, a recorder amplifier 82 connected to the output of filter 78 through conductors 80 and a recorder 86 connected to the output of recorder amplifier 82 through conductors 84. Suitable sources of power for operating the various components of the system as ell as switching means for filter 78 may easily be determined by those skilled in the art to which sensors 70 and 71 may take the form of a Kaman Measuring System's Model KD-2300-10C multipurpose variable impedance transducer for non-contacting measurement of conductive surface motion.

Referring to all of the figures of the drawings, when it has been determined that a profile extending along the longitudinal dimension of a railway track system is desirable to determine the maintenance of the upper portions of the rails, the apparatus is simply connected to a suitable source of locomotion at approximately eight km per hour and, a suitable means for correlating the location of the profile in the track system may be employed in the form of an integrator for a speedometer of other forms of positional determination and recording. The lateral forces exerted on skids 20 and 21 serve to maintain the lateral position of sensors 71 and 72 at substantially the midpoint of the top surface of the rail and the weight of the skids themselves and the suspension system serves to maintain the lower skids 20 and 21 in contact with the surface encountered in the period.

Claims

1. The method of determining the nature of the upper surface of a railroad track, comprising; providing a skid-like member having a longitudinal dimension of approximately twice the expected crest-to-crest dimensions of corrugations in the upper surface of a railroad track; moving the skid-like member along a track to be analyzed for corrugation wear; determining the vertical distance from the near center of the skid-like member; and, recording the variations in said vertical distance.

2. Apparatus for determining the extent of wear corrugations in the upper surface of a railroad track, comprising; a skid-like member having a longitudinal length substantially equal to twice the distance between the crests of rail corrugations; means for transporting said skid-like member longitudinally of and in contact with a track; and, proximity determining means mounted nearthe center of said skid-like member in nonconducting proximity to the upper surface of said track.

3. A method of determining the nature of the upper surface of a railroad track substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

4. The apparatus for determining the ex tent of wear corrugations in the upper surface of a railroad track substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.