US2671197A - Magnetizing means for rail flaw detector systems - Google Patents

Description

March 2, 1954 W. C. BARNES ET AL MAGNETIZING MEANS FOR RAIL. F'LAW DETECTOR SYSTEMS 4 Sheets-Sheet 1 Filed Sept. 2, 1950 ml h m M W 6 an J C. BARNES ET AL March 2, 1954 4 Sheets-Sheet 2 Filed Sept. 2, 1950 ZOCOUNIO hwwlr INVENTORS. Wa/z er 67136127228 77? (fife?) Kids I aiziw w w 293:5 VS: l 52 US as M zoCSEE 55 v W9 ovum momma zoiuwEQ x3: Y

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March 1954. w. c. BARNES ET AL MAGNETIZING MEANS FOR RAIL .FLAW DETECTOR SYSTEMS Filed Sept. 2, 1950 4 Sheets-Sheet 3 JNVENTORS March 2, 1954 w. c. BARNES ET AL 2,671,197

MAGNETIZING MEANS FOR RAIL FLAW DETECTOR SYSTEMS Filed Se t. 2, 1950 4 Sheets-Sheet 4 IN VEN TORS Patented Mar. 2, 1954 PAT E NT 0 F F I C E 2267 List- MEANS BMEFBAW DETECTOR SYSTEMS Ap iieations'eptemter 2, 1950, Serial No. 183,038

I V 'r'o'dhcin lon'gitllliinttl' into the" rail is disclosed in Barnes and Kfeevil Patent No. 2,3171720; issued concurrently therewith: ,x

miaarnes'etar Patent 2331-1720, the ma neuzme means comprisesthr'ee longitudinally spaced eleetrcmag'nets each having a separate function'tsperform prsperivmsgnenzin'g the rail; The reward" magnet, or" as it is usually calledi; themagnet is ayelatitely powerful they actmore or less independently. The'third magnet; commonly ifetjeired fie as o ma is net a'spbwerfiil'a's'the and "B" ma i and it intranet-es re ativ ly levyintens ty magfietib flntif iiitoi th rail: The" "0" ma net is semen referrea was a cleanp magnet} eqa'use 1t hasth'e-efie et dferas'i'rig certainresiduail nlqs left: by the" rr ar'icr "B" magnetsvicinity dfsuperneiai defectsin the fair seen as biii'ii's, gags, eta:

The present invent bn seeks to moreenec't ve way offintioilucing agiieti'c flux intothe? rai1-rbrt epraence o'f the iiivefition dise dsee said Barnes" and" Keevil Pate is lit. 23171718, and to" accomplish this result with" less equipment and" less bulky pparatus than that empmyeu n-theeames and Keevnpatents Iie'r'etbfoie' referred fie;-

improved magneti n meansaisshas rtsr'ari'obiecr reater selective ess ii l il j' 0 s'uclf'inteinaldefect' desired residualzmagnetic fieids iii the' vi'e inity df' Biissil'cl April 27; 1th, and

provide" fai- 15 cities: (01; set-a transverse fissures and in attenuating the establishmentof residualfields in the vicinity of superficial' defects; other and further advantages are obtained; as will become apparent as the disclosure proceeds and the description is read in coniunctionwith the accompanying drawings,

' Fig. 1 is a" diagram sideelevation which will be used in explaining the principles" which are believed to underlie the present invention Figs; 2,, 3yand 4- are viewsshowing; three possible arrangements for the auxiliary flux-orienting device;

Figs; 5 and: 6 are diagrams inplan which will also be used inexplaining, the invention;

Fig. 7 is aside'elevationalview of the second magnetizingmeans used in-impartingthe desired residual magnetic characteristics to the rail;

Fig. 8 is an endelevat-iona-lview ofthe form of the auxiliary magneticdevice shown in diagram in-Fig. 3;

- Fig.- 9 is asectionalview taken on the' line 9'--9*'of: Fig. 8;

} Fig: 10 is aside elevational view of the auxiliary flux-orienting device showing particularly the gaugerunner andthemanner inwhich it is attached to" the auxiliary device Fig. 1-1- is a fragmentary sectionalview taken onthe'line: l-l-1--l of Fig 10-; and

Fig: 12* is an explodedperspective view illustrating: the" manner in which a contact shoe for the auxiliary magnet is removably mounted in placer It will be understood thatthe specific description or certain-preferred-formsof the invention is -f-orthe purposeof complying with section 11-2, title 35' of the United-StatesGode, and that the invention maybe variously modified within the scope of the appended claims;

General organization this invention: relates primarn to the niagneti-iing means; 1: escriptmn: W111 be limited w th :ntvet perm of suchmeans; refer- I eri-ee: min I made to said prior Barnes, et a1.

plained in Barnes et a1. Patent No. 2,317,720, the fiux pattern is characterized by a first reversed fiux indicated by the arrow 22, then a strong rearward flux indicated by the arrows 23, and then a second reversed flux indicated by the arrow 24, this latter being caused as the fiux rises upwardly from the rail to pass through the coil 2|.

According to the present invention, the "3 and C magnets are dispensed with, and instead, a magnet generally designated 25 is employed which for convenience will be referred to as an F magnet. This magnet has two adjacent forward poles 26 and 21 upon which series connected coils 28 are wound, and these coils are energized from a suitable direct current source, preferably 110 volts D. C.

Since the coils 26 are wound in the same direction, the flux through the poles 26 and 21 will likewise be in the same direction, and assuming proper polarity connections for the coils 28 so that the fiux through these poles is directed downwardly, it will be seen that the "F magnet produces first a reverse fiux indicated by the arrow 29 and then a strong rearwardly directed flux indicated by the arrows 3D, and for reasons which will be explained later, there is no second reverse flux to correspond with the flux 24,0f the A" magnet.

The F" magnet 25 has a horizontal pole 3| which is substantially parallel to the rail and preferably on the order of ten inches above the rail.

An auxiliary magnet 32 is mounted beneaththe trailing end of the pole 3|, and it is this magnet that is largely responsible for the unique results obtained by the improved magnetizing means of this invention. The auxiliary magnet 32 is preferably, although not necessarily, unidirectional in character, and its purpose is to conduct flux from the rail upwardly to counteract the strong vertical field that is introduced into the rail by the poles 26 and 21, and also to set up a relatively intense momentary transverse flux along the top surface of the rail which not only serves to wipe out certain undesirable residual fields introduced by the A magnet or by the poles 26 and 21 of 'F magnet, but also to place the rail in a more cyclic condition for the main rearwardly directed energizing flux t'o polarize transverse fissures.

' In Fig. 2, the auxiliary magnet 32 is a direct current magnet having a central pole 33 which is part of the magnetic circuit that includes side poles34 and 35, each'of which mounts a coil 38 connected to a suitable direct current source in such manner that flux travels downwardly through the poles 34 and 35, then inwardly through triangular poles 31 to the central pole 33, and then back through the coils 36 through a top pole piece 36.

In Fig. 3, the side pole 34 and its supporting coil are eliminated, and in Fig. 4, only the central pole 33 is used. This pole may be in the form of a permanent magnet with the poles arranged for the flux to travel upwardly, or it may be a soft iron member which merely provides a path of low reluctance for the flux to return to the trailing pole 3| of the magnet 25.

Following the A magnet and the "F" magnet with its auxiliary magnet 32 is an induction pickup generally indicated at 39, which is located far enough behind the magnet 25 to be outside of its active field. The pickup 39 is connected to suit able amplifying and recording apparatus which forms no part of the present invention.

Improved results from use of apparatus In any rail magnetizing equipment, it is de-' sirable to polarize such internal defects as transverse fissures and to avoid magnetization or polarization of such superficial rail defects as burns, scale, gags, corrugations, and the like. After a rail has been magnetized, any attempt to erase the polarized conditions in the vicinity of the superficial defects necessarily involves the attendant danger of erasing or weakening the fields in the vicinity of transverse fissures.

In the present invention, test results indicate that not only are transverse fissures more fully and more strongly polarized by the magnetizing means of this invention, but at the same time, superficial defects are energized to a far lesser extent than has heretofore been possible. For example, on one test where the test apparatus had a sensitivity such as to record all known fissures in the test track, only three false indications were recorded, whereas duplicating the test using standard magnetizing means produced over thirty false indications. i

One interesting benefit from this improved magnetizing means and the more certain polarization of all transverse fissures with lessened en'- ergization of superficial defects is that the detecting equipmentcan be run with less sensitivity to still further reduce the number of false indications that are recorded. The use of less sensitivity in the amplifier is made, possible by the more certain polarization of transverse fissures by the magnetizing means of this invention.

In dealing with magnetic phenomena, it is not always possible to known for a certainty the reasons which underlie facts known to exist, and it should be understood that in the explanation that follows and in all other attempted explanation of the magnetic phenomena underlying the present invention, certain hypotheses must be made, and there is no intention of conveying the'impression that these hypotheses are the only ones for explaining the improved results of the present invention. V

The theory which is believed to underlie the improved results, therefore, is that the strong flux 30 (Fig. 1) which is made to travel rearwardly through the rail without any substantial subsequent reversal of fiux, strongly magnetizqs any transverse fissures that may be interposed in its path, and by mounting the coils 26 on the forward vertical poles 26 and 21 rather than on the horizontal pole 3| (in a manner that would correspond to the coil 2| of the A magnet 20) the rearwardly directed flux 30 leaves the rail very gradually as indicated by the arrows 50', and does not set up a reverse flux that would tend to weaken the polarization of the transverse fissures.

In addition to this action which more strongly polarizes the transverse fissures, the auxiliary magnet 32 enhances this action by momentarily shifting the magnetic orientation of some ofv the molecules in the portion of the rail over which the magnet 32 passes. However, the magnet 32 has a more important function of wiping out, or at least reducing the residual fieldsleft in the vicinity of superficial defects, andthis is believed to be due first, to the passage of some portion of the main flux 30 upwardly through the pole 33, and second, to the quick reversal or shifting of flux that takes place immediately adjacent to the top surface of the rail as flux passes laterally through the top surface of the rail head from poles 34 and 35 to the central pole 33. Apparstainless steel brackets 54 and 55.

ently this sharp shifting of the flux pattern on the top surface of the rail tends to wipe out the residual magnetic conditions which existin these areas, and this is accomplished without adversely aflecting the magnetization and polarization of transverse fissures.

However, in order to be more certain that transverse fissures are not adversely affected by the lateral flux introduced into the railby the magnet 32, the unsymmetrical arrangement of the magnet 32 in Fig. 3 is preferred with the center pole 33 being almost directly over the center line of the rail or slightly to the outer edge of the rail indicated by the reference character 8|. This places the pole 35 well over the outer edge of the rail 5|, and strangely enough, this arrangement of the auxiliary magnet 32 not only provides slightly improved detection of transverse fissures (which are normally found closer to the gauge edge 52 or" the rail than to the outer edge 5|), but also is more effective in removing false indications due to scale found on thefgauge edge 52 of the rail.

The indications are that the pulling up of the main flux 30 through the core 33 accounts for possibly fifty per cent of the burn and corrugation indications that would otherwise appear on the record, with the lateral flux'indicated by the lines 53 accounting for the other fifty per cent of the reduction in false indications due to these causes. For gags (which are caused by hard spots in the rail due to bending of the rails at the mill), and for scale the lateral flux 53 appears to be of considerable importance even though it is difficult to explain why indications due to scalc'on' the 3 gauge edge of the rail 52 are effectively eliminated by use of an auxiliary magnet of the form shown in Fig. 3 which is positioned substantially over the outer portion of the rail head. It may be due to the flux conditions indicated in Figs. 5 and 6. which show that even when the auxiliary device is assym'metrically arranged, some of the main flux is laterally diverted, which produces a quick shaking up of the molecules in the adjacent portions of the rail.

The 'F ma'gnet The ".F magnet 25 is best shown in Fig. 7, and it is supported from thecar which carries it by The pole pieces26 and 21 are suspended from the horizontal pole 3| by bolts 51 and clip's58 hold the coils 28 in place on the poles 26 and 21. Preferably the bottom ends of the poles 2B and 21 are magnetically connected by a bridge 59 of cold rolled steel bent at the ends as indicated at 60 to assist the magnet in riding over obstacles.

Purely by way of example, the horizontal pole 3| may comprise a bar of cold rolled steel approximately 36 inches long and 2 x 6 inches in crosssection, and the poles 26 and 21 may be approximately 8 inches in length and of like cross section. The coils 28 may have 2926 turns apieceof 16- gauge enamelled wire, and when energized from a 110 volt D. C. source, and connected in series, will draw approximately 2 amp. of current.

The poles 2S and 21 may be spaced apartaxdistance of approximately 5 inches.

The auxiliary magnet 3-2 and its mounting The auxiliary magnet 32 is carried by the magnet 25 on a support generally indicated 6| which provides for universal movement of the magnet with respect to the F magnet 25. The support 3| includes a steel bolt 62 which passes through the horizontal pole 3| and is anchored in a stain less steel braclset'63. The bolt 62 passes through spaced collars 64 which are also secured to the bracket 63, thesecollars constituting a bearing support for the bolt 62 and permitting the entire support 6| to rotate about thebolt 62 as a pivot.

A brass bar 65 is pivoted at- 36 to the bracket 63 and is urged downwardly by a spring 61 secured at one end to the bar 65 and at the other to a horizontally extending arm 68 of the bracket 63. The bar 65 may be lifted about the pivot 66 by any suitable means controlled from the car interior, as, for example, by a cable generally indicated at 69.

The magnet 32 is mounted at the free end of the bar 65 on a vertical pivot/1D so that the magnet can rotate about this pivot as may be required to properly v follow the rail head.

The center pole 33 of the magnet 32 is preterably maintained in direct contact with the rail head H by means of a replaceable shoe 12 of mild steel which is beveled at 13 enabling the shoeto ride over rail joints, and which has trunnion bearing 14 adaptedto be received within slots '15 (see Fig. 12) of the center pole 33. The shoe 72' is conveniently locked in place by a removable angle bracket 16' which is bolted to the poles 33 by bolt H.

At the lower end of the pole 35 which carries the magnet coil 36 is secured the triangular pole piece 31 and for convenience, this .pol'e' piece mates with a brass piece 18, both of which are drilled to receive a securing bolt 1'9, that is threaded into the center pole piece 33.

Hinged to the lower end of the pole piece 35 are a pair of gauge brackets which are adjustably secured by bolts 8|: to a gauge runner 82 of stainless steel. The bolts 8| are mounted in slots 83 so that the gauge runner 82 may be adjusted laterally to the brackets 80 to thereby position the center pole 33 atselected positions over the rail head.

The bolt 84 which supports the brackets 80 serves as a pivot for rotation of the brackets 80 and'gauge'runner 8 2 as movem'ent of the-car with respect to" the rail makes such swingingmovement of the gauge runner necessary.

It will be" understood that the entire support 6| is resiliently biased against the gaugeedge 52 of the rail as shown diagrammatically at $1, and the endsof the gauge runner are. flared: outwardly as indicated at85 and upwardly at 86 to enable the gauge runner to ridesmoothly over the rail.

Purely by way of illustration, the coil 33 of the auxiliary magnet may have 1 0,800 turns of No. 30- enam'ell'ed copper wire, and when connected to a volt D. C-.- source,- will draw approximately .2 amp.

Although it is preferred to use direct current for the coil 36, it will; be undertsood that under some circumstances, alternating current of the appropriate frequency may be used. A Gil-cycle frequency is satisfactory.

In some practices of the invention, itv may be desirable to use more thanone magnet of the type exemplified by the magnet 23 to precondition the rail prior to" subjecting it tothe action of the F" magnet 25 and" the auxiliary magnet 32. Other means for placing the rail in acyclic condition prior to the final flux en'ergizatio'n of "F magnet 25 and auxiliary magnet 32' may also be used.

Weclaim:

1-. The method of magnetizing r'ailsand-the like to establish characteristic residual magnetic through the rail, and simultaneously with such longitudinal magnetic energization of the rail progressively subjecting at least a portion of the top surface of the rail head as it is being energized to the action of an independent unidirectional transverse flux.

2. The method of magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, which includes progressively passing a relatively strong, unidirectional, longitudinal flux lengthwise through the rail, and simultaneously with such longitudinal magnetic energization of the rail progressively subjecting at least a portion of the top surface of the rail head as it is being ener- -.gized to the action of a unidirectional transverse fiux that is introduced into the rail and passes out of the rail through said portion of the top surface.

3. The method of magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, which includes progressively passing a relatively strong,

unidirectional, longitudinal flux lengthwise through the rail, and simultaneously with such longitudinal magnetic energization of the rail progressively subjecting at least a portion of the top surface of the rail head as it is being energized to the action of an independent unidirectional transverse flux that is maintained at a relatively shallow depth through said portion of the rail top surface.

4. In apparatus for magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, said apparatus comprising a main magnet having a member of relatively high permeability mounted with its lower end in substantial contact with the rail and having means associated therewith for passing a unidirectional magnetic flux laterally through at least a portion of the rail head.

5. In apparatus for magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, said apparatus comprising a main magnet having a horizontal pole mounted over the rail and substantially parallel thereto, a vertical pole adiacent the forward end of the magnet, and an auxiliary flux-orienting device located at least in part beneath the trailing end of said horizontal pole, said auxiliary device including a vertical member of relatively high permeability mounted with its lower end in substantial contact with the rail and having means associated therewith for passing a unidirectional magnetic flux laterally through at least a portion of the rail head, said last-named means including a direct current vertical coil positioned alongside and laterally of said vertical member, and an iron circuit associated with the coil, said iron circuit including said vertical member and being closed except for an air gap closely adjacent the top surface of the rail.

6. In apparatus for magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, said apparatus comprising a main magnet having a horizontal pole mounted over the rail and substantially parallel thereto, a vertical pole adjacent the forward end of the magnet, and an auxiliary flux-orienting device located at least in part beneath the trailing end of said horizontal pole, said auxiliary device including a vertical member of relatively high permeability mounted :with itslower end in substantial contact with the rail and having means associated therewith for passing a unidirectional magnetic flux laterally through at least a portion of the rail head, said last-named means including a direct current vertical coil positioned alongside and laterally of said vertical member, an iron circuit associated with the coil, said iron circuit including said vertical member and being closed except for an air gap closely adjacent the top surface of the rail, and a like vertical coil and iron circuit positioned diametrically opposed to said firstnamed vertical coil and iron circuit.

'7. In apparatus for magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, said apparatus comprising a main magnet having a horizontal pole mounted over the rail and substantially parallel thereto, a vertical pole adiacent the forward end of the magnet, an auxliiary flux-orienting device located at least in part beneath the trailing end of said horizontal pole, said auxiliary device including a vertical member of relatively high permeability mounted with its lower end in substantial contact with the rail, and flux-producing means associated with said vertical member for passing magnet fiux through said auxiliary device including a verical member of relatively high permeability mounted with its lower end in substantial contact with the rail and having means associated therewith for passing a unidirectional magnetic flux laterally through at least a portion of the rail head, said last-named means including a direct current vertical coil positioned alongside and laterally of said vertical member, and an iron circuit associated with the coil, said iron circuit including said'vertical member and being closed except for i an air gap closely adjacent the top surface of the apparatus comprising a main magnet having a horizontal pole mounted over the rail and substantially parallel thereto, a vertical pole adjacent the forward end of the magnet, an auxiliary flux-orienting device located at least in part beneath the trailing end of said horizontal pole. said auxiliary device including a vertical member of relatively high permeability mounted with its lower end in substantial contact with the rail. and a removeable wear shoe atthe lower end of said vertical member, said wear shoe having trunnion bearings engageable within slots in said vertical member, and means for locking said bearings within said slots.

10. In apparatus for magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, said apparatus comprising a main magnet having a horizontal pole mounted over the rail and substantially parallel thereto, a vertical pole adjacent the forward end of the magnet, an auxiliary flux-orienting device located at least in part beneath th trailing end of said horizontal pole, said auxiliary device including a vertical member of relatively high permeability mounted with its lower end in substantial contact with the rail, a removeable Wear shoe at the lower end of said vertical member, said wear shoe having trunnion bearings engageable within slots in said vertical member, and a bracket for maintaining the trunnione bearings within said slots.

11. In apparatus for magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, said apparatus comprising a main magnet having a horizontal pole mounted over the rail and substantially parallel thereto, a plurality of vertical poles mounted adjacent the forward end of the magnet, and an auxiliary flux-orienting device located at least in part beneath the trailing end of said horizontal pole, said auxiliary device ineluding a vertical member of relatively high permeability mounted with its lower end in substantial contact with the rail and with its upper end effectively spaced from said trailing end.

12. In apparatus for magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, said apparatus comprising a main magnet having a horizontal pole mounted over the rail and substantially parallel thereto, a plurality of ver-- tical poles mounted adjacent the forward end of the magnet, and a bar of highly permeable material joining the vertical ends of the said poles, and an auxiliary flux-orienting device located at least in part beneath the trailing end of said horizontal pole, said auxiliary device including a vertical member of relatively high permeability mounted with its lower end in substantial contact with the rail.

13. In apparatus for magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, said apparatus comprising a main magnet having a horizontal pole mounted over the rail and substantially parallel thereto, a plurality of vertical poles mounted adjacent the forward end of the magnet, and a coil mounted on each of said vertical poles, wound in the same direction, and adapted when energized with direct flux to direct flux through said poles in the same direction, and an auxiliary flux-orienting device located at least in part beneath the trailing end of said horizontal pole, said auxiliary device including a vertical member of relatively high permeability mounted with its lower end in substantial contact with the rail.

14. In apparatus for magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, said apparatus comprising a main magnet having a horizontal pole mounted over the rail and substantially parallel thereto, a vertical pole adjacent the forward end of the magnet, and an auxiliary flux-orienting device located at least in part beneath the trailing end of said horizontal pole, said auxiliary device including a vertical member of relatively high permeability mounted with its lower end in substantial contact with the rail, said auxiliary device being mounted on said horizontal pole of the main magnet and having universal movement with respect thereto.

15. In apparatus for magnetizing rails and the like to establish characteristic residual magnetic fields in the vicinity of transverse fissures, said apparatus comprising a main magnet having a horizontal pole mounted over the rail and substantially parallel thereto, "a vertical pole adjacent the forward end of the magnet, an auxiliary flux-orienting device located at least in part beneath the trailing end of said horizontal pole, said auxiliary device including a vertical member of relatively high permeability mounted with its lower end in substantial contact with the rail, said auxiliary device being mounted on said horizontal pole of the main magnet and having universal movement with respect thereto, a gauge runner carried by the auxiliary device, and resilient means for biasing the gauge runner against the gauge edge of the rail.

WALTER C. BARNES. WILLIAM BRAZITIS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,250,459 Barnes et a1 July 29, 1941 2,311,715 Thorne Feb. 23, 1943 2,425,857 Barnes et al Aug. 19, 1947 2,497,855 Barnes et a1 Feb. 21, 1950 2,497,856 Barnes et a1 Feb. 21, 1950 2,602,840 McKee et a1. July 8, 1952 2,622,131 McKee et a1. Dec. 16, 1952

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