US2767261A - Brush holder - Google Patents

Description

Oct. 16, 1956 F. H. KEAT'ON ETAL BRUSH HOLDER 3 Sh eetsSheet 1 Original Filed Sept. 24, 1948 2.5: II Q: 3%?2 INVEyTORS.

0d. 16, 1956 F. KEATON ET AL 2,767,261

BRUSH HOLDER Original Filed Sept. 24, 1948 3 Sheets-Sheet 2 if iii Oct. 16, 1956 F. H. KEATON EI'AL 2,767,261

BRUSH HOLDER Original Filed Sept. 24, 1948 lMu/MM United States Patent C) BRUSH HOLDER Frank H. Keaton and David C. Bettison, Omaha, Nebr.

Original application September 24, 1948, Serial No. 50,962. Divided and this application April 4, 1951, Serial No. 220,120

5. Claims. (Cl. 191-49) Our invention relates to a carriage for introducing high amperage, low voltage current into a rail for the purpose of flaw detection, the carriage also being used to support the inductive pickup that searches the magnetic field above the rail for non-uniformities in field strength, such nonuniformities generally being indicative of discontinuities in the rail.

In electro-inductive rail flaw detection a pickup is used to measure the strength of the magnetic field about the rail, the upper surface thereof normally being the portion traversed by the pickup. Since the strength of the surrounding field may vary about the difierent portions of the rail and will vary at different distances from the same surface of the rail, it is highly important that the pickup be maintained a constant distance from the rail and that a substantially constant alignment of the pickup with respect to'the rail be kept during the detection process. Y

;In view of the fact that it is necessary in the electroinductive system of testing to search the rail with the pickup between the electrical brushes that makecontact with the rail, it is generally the practice to mount both the brushes and the pickup on a unitary mount or carriage. One advantage of this is that it facilitates raising these elementsoif the rail when they are not in use and again re-positioning them on the rail when further testing is to be performed. However, the mounting of both the brushes andrthe pickup on a single carriage introduces some complications, for not only must the pickup maintain a constant orientation and spacing with respect to the rail, but the brushes, spaced out to either side of the pickup, must remain in contact with the top surface of the rail and exert sufiicient pressure against that surface to insure the making of a good electrical connection.

Some of the factors which create difiiculties with conventional type carriages or with supporting frames carried by the vehicle may be briefly enumerated.

' 1. Constant orientation and alignment with respect to the rail must be maintained not only when traversing straight track but also along curves of varying radii. On curves such mountings will not conform to the arc of the rail curve but rather will be aligned with a chord of that are, thereby moving the pickup laterally away from the longitudinal axis of the rail.

2. Variations in the level of the rail between the supports for the mounting will result in varying the spacing of the pickup to the rail.

A principal object of the present invention is to overcome the foregoing problems and to provide a mounting in which the pickup and brushes will maintain asubstantially constant orientation with respect to the railand 1n which the pickup will be maintained a substantially constant distance above the upper surface of the rail.

"Additional objects and advantages include: amount,- ing which is easily raised from, or lowered to, operative engagement with the rail; a mounting requiring little or no maintenance over extended periods of time; a spring biasing for the brush holder, which is readily accessible for adjustment of the pressure with which the brush bears against the rail; a brush holder which will hold along brush thereby reducing the frequency with which the brushes must be replaced, and in turn reducing the loss from the discard of unusable brush stubs; and, a brush holder in which the brush clamps are located in a position easily reached to replace the brushes or to increase the exposed length of the brush.

Additional objects and advantages will be apparent from the following description read in conjunction with the drawings, in which:

Fig. 1 is a side elevation of a rail detector car;

Fig. 2 is a perspective view of the carriage frame upon which the electrical contact brushes and pickup are mounted and showing the means for moving the carriage to and from the working position;

Fig. 3 is a section taken at line 3-3 of Fig. 1;

Fig. 4 is a perspective view of a pickup with the mounting brackets therefor;

Fig. 5 is a plan view of the carriage;

Fig. 6 is a side elevation of the carriage;

Fig. 7 is a section taken at line 7--7 of Fig. 6;

Fig. 8 is a section taken at line 8-8 of Fig. 7; and

' Fig. 9 is a perspective view of a brush holder.

In the detection of flaws in rail a car 10, such as shown in Fig. l, is used to transport the detection apparatus, personnel and related equipment along the track with the detection process taking place en route. In the electroinductive system of testing, the car will house the generator for providing the necessary current to energize the rail, the recording mechanism, under the supervision of one or more operators, to indicate the presence of nonuniformities in the magnetic field about the rail, and the necessary equipment to provide the propulsive force for moving the car along the'track. The car is borne on flanged wheels 11, the axles of which are rotatably engaged in journal boxes 12 and 13. The car is supported through suitable springs from the journal boxes.

1 Carriage The brush carriage, indicated generally by 16, consists of two ' frame members 17 and 18 positioned end to end substantially over the rail With the adjacent ends of the members connected by means of a universal joint 19. Frame member 17 is formed of a pair of spaced angle irons 20 and 21. At the end of member 17 adjacent member 18 (referred to for convenience as the adjacen end) the angle irons are spaced by means of end 23 of universal joint 19 and insulator blocks 24 mounted between end 23 of the universal joint and angle irons 20 and 21. Bolts or rivets 26 serve to assemble the angle irons, insulator blocks, and end of the universal joint. Insulated sleeves 27 about the bolts or rivets 26, in conjunction with insulator blocks 24, prevent electrical contact from being mad -between the frame member 17 and the universal joint 19. 7

At the non-adjacent end of frame member 17 the angle irons are spaced by end 23 of support arm 29 and insulator blocks 31. Rivets 32 hold the angle irons securely assembled and attached to end 28 of support arm 29.

' Insulating sleeves 33 in conjunction with blocks 31prevent electrical contact between frame member 17 and support arm 29.

Support arm 29 is bent as indicated at 33 in order that the outer end of the arm 34 will extend outwardly of the journalbox 12. Bolt 36, passing through longitu dinal slot 37 in arm 29, supports the arm from journal box 12. The slot, coupled with the fact that the arm 29 is loosely supported between the head of bolt 36 and journal box 12, allows both pivotal and longitudinal movements of the carriage with respect to the journal box 12, which movements'are necessary to permit carriage 16 to be raised and lowered as hereinafter described.

The construction of frame member 18 and its mounting by means of support arm 38 is substantially identical th foregoing descriptionof frame member :17 and uppqrtarm 219 except that no provision is made for longiiud nal movement of armt38 with respect to journal box 13. Ihe normal direction of ear movement during test' 11 QPerations is indicated in Fig 1, and it will be seen i that J'Qul'nal 13 will be at the leading end of the car. A! the leading end of the carriage it is desirable to only allow pivotal movement ofi'thetcarriage with respect to tithe car, and thus no ,slot is provided inarm 38.

I 'Thearticnlated (adjacent) endsof framernembers '17 and 18 are supported in constant alignment withthe' rail by means of flangediwheelAl conncted to fr ame 'mem ber lfi throughplates 42 and 43. Plates I42 and Hate ettachedito member 18tby means of -rivets i iwliicli' e61- IreSPQDd'QlLO rIiYCtS Z 6Yon frame member Bolt 46, interconnecting plates 42 and 43, forms an axlefor wheel 41. Insulatingibloeks' and sleeves prevent an electrical connection :between frame member 18, universal joint 19 and/or wheel 41.

a mechanism In manyins tancesa detector car must be movedrfrom poipt tq point without the necessity of performing fiaw detection en rgute. In such cases it is highly desirable 19 1. 19)? heelectrical contact brushes out of engagement wi h the rail to prevent undue wear on the brushes. To PSifiQXH) his f n 'tiqn we havetprovided a fluid-operated pistgn mec hanism 51, and a spring 52 to lower and'raise, W eiy, the carriage 16. (see Figs. 2 and 3). The pper epdgf thepiston mechanism 51 and spring 52 are Q Q 9 ihetframe f thelcar 10 through insulating block 53, thepu rpose of thfiblQCkl being to prevent elect i l eontaqt between car 10 and carriage 16. Bracket '55; afiigged to carriage frame member 18,v is provided with an opening 556 into which is received the end of piston rodSfl Qf piston mechanism 51. Opening 56 is somewhat larger :in diameter than the end of piston rod 57 P Imit;=8 gular movement of the piston rod with respect to'bracket 54. Semi-SPhetical-shaped member 58,

afiixed to piston rod 57,-'seats against'the upper face of 1 s sister; eise QW t r to, u e a dpubler n mechanism Ijbd i e nd lette -the. e A i .Q @15 h ve t e disa va es; f l Pre s r 0.11 the, nis anw nlcl s th a riase. 9, s 2me19n i afai re c fluid Pres re t *9. rai e. he carri sea d n Y t ni t esu rom inordinate "big ini r H l'ci iveriiig 6f theca rr ia g a V hen-th car is t avel n i h u stin b in Pe me 'enw e t m y e d s bl to suspen th car: iag q ahdk59; he n o W i ss1 ppdthr n h bailing 9 i br sk wer -ren eunq n qft e lro 'er i i r le aa m 1 er es t push, h a ria e ou wardly to bring the flange of wheel 41 into engagement with the side of the rail and to hold it there duringlhe testing procedure so' that the articulated P 116 1 of the carriage will maintaina definite orientation with re'spect to the'r'ail. The: upper portion of piston'assernbly 61 is supported: from car '10'through insulating bracket Q2, and the piston rod 63 of the assembly is aligned with and bears against bracket'54in the same manner as previous-1 y d sc d fo P n s mbl 5 nd Pis o mid 57 Spring 64, 'connected'at one end to'insulating bracket 62- and at theother end to carriage bracket 54, ism;- tended by the outward movement of piston rod 63. When the fluid pressure on piston mechanism 61 is relieved, the spring will bring the carriage 16 inwardly away from 7 its position above the rail. Ball joint 66 at the upper end of piston assembly 51 allows that assembly to swing to facilitate the inward movement of the carriage '16. Similarly, a ball joint 67 at the upper end of piston assembly 61 allows that assembly to follow the ppward downward rnovements of the carriage.

.T c pr s ure lewer ne the e rin s t9 st apply anathema o p t9n-asseml5ly 51 m bring'wheei 41 down against the top of the rail. The carriage -16Iwill at this point he swung somewhat inwardly by the action of spring 64, although this displacement is not very large and the length of wheel 41 is suflicient to assure that the wheel will come into contact with the top of the a l, A ter the Wh e has come in rest againstltheltop 9; F 1? ai .flll tl M9 5 3? is app ed to piston assembly 451 'msz in th a ria e ou wardlytand bringin'gthe flange 91 titan e q en a ementwith the side .otthe Irail. ilni mes y; L le t on hesetwopiston assembliesdur: maths: tsstin epe atiqn t gs kc pingnthe wheels-firmly against the top of the rail with the flange of the wheel ares es asain hesisiep th rail 7 Thus, the adjacent end membe s 17 and 18 W l ie maintained at a .constan Q ken over the ail and'in -S 9Il$ 1n alignments with; r nnet t9 the rail 7 v sk-HP me nin T: The ran T 2 Pieter 7 a a hraqke fl a es? outer. l gffiflthe clip is pro! end f h? 2 i {3: 2 bf St hre ddlin spe ng lower end' of flboltpqli" is over the. outer ,etol y-a .e t erlasrfaat ae'eaeei upper-end of the spring bears against the under-face of clip 92, and the lower end of the spring bears against a nut 98 threaded onto bolt 93. The nut may be moved up or down to adjust the compression of the spring.

At the upper end of bolt 93 above .clip 92 is a nut 99 which, when the carriage is lowered into engagement with the rail, will be spaced somewhat from the upper face of clip 92 due to compression of spring 97 by the pressure of brush 87 against the rail. The purpose of nut 99 is to allow only a limited extension of spring 97, and consequently the brush holder, as the carriage is raised and the brush is no longer bearing against the rail.

Pigtails 101 are connected to the source of electrical energy within the car and to the brush holders externally of the car. The pigtails may be attached to the upper end of bar 83 of the brush holder 81 through a connecting screw, or by welding. Bar 83 is preferably made of a copper base alloy and provides a low resistance path for the electrical current to the brush, the resistance being sufliciently low that variations in the length of the brush within tube 82 will not cause any appreciable change in the voltage drop between the source of electrical current and the end of the brush.

Operation From the foregoing description it will be appreciated that a carriage has been devised which is not only easily applied to a detector car designed for it, but also may be used in the conversion of existing detector cars. It may be made to fit almost any size of existing car merely by changing the lengths of support arms 29 and 38 and may be readily hung from the existing journal boxes by the addition of bolts 36. The only other necessary structural connection to the car is that provided through brackets 53 and 62, which may be easily mounted Without involving any fundamental changes in the existing car.

Initial adjustments include: pre-setting the position spring pressure used to hold the brush against the rail, which is done by means of nut 98; setting nut 99 sufliciently above clip 92 to allow for some wear of the brush before the brush must be re-set and yet sufliciently close to clip 92 that the brush will be well above the upper surface of the rail when the carriage is moved into raised position; and positioning pickup 71 in the desired alignment and distance to the rail.

Before starting each days testing run, or oftener if necessary, the operator of the car should examine each brush mounting to observe the spacing between nut 99 and clip 92. If the space is not adequate to allow for the wear of the brush until the next inspection period, set screw 86 may be loosened and the brush may be extended a greater distance from the holder, whereupon the set screw is again tightened. Due to the positioning of the set screw at the bottom end of the brush holder, it is a very simple matter to make this correction with the carriage suspended in the raised position. The particular mounting of the brush holder from the carriage permits tube 82, in which the brush is held, to be made much longer than has been possible with prior devices. A longer brush holder allows the use of correspondingly longer brushes with an increase in the wear of an individual brush and with a decrease in the loss occasioned by the discard of unusable brush stubs.

After the length of the brushes has been correctly adjusted, fluid pressure is applied to piston mechanism 51 to lower the carriage and to piston mechanism 61 to move the carriage outwardly, with the flange of guide wheel 41 in contact with the inner face on the rail. Wheel 41, being held securely in contact with the upper and side faces of the rail, will assure that the adjacent ends of frame members 17 and 18 are maintained at substantiaily constant distances above the upper face of the rail and in substantially constant alignments with respect to the longitudinal axis of the rail.

The pickup, being supported from the adjacent end of frame member 17, will be held in the pie-set ali nment and spacing from the rail. The use of the detector car on straight track or curved track of varying radii will cause no substantial change in the positioning of the pickup, nor will low spots in the track vary to an appreciable extent the spacing of the pickup to the rail.

The brushes, being spaced only a short distance to either side of the universal joint, will reflect only to a very limited extent the movements that may occur in the outer ends of support arms 29 and 38. The brushes will at all times maintain a substantial face contact with'the upper surface of the rail and insure a good electrical connection thereto. v

It should be understood that the particular embodiments of the invention shown in the drawings anddescribed herein are for the purpose of complying with Section 112, Title 35, of the United States Code and should not be construed as imposing limitations on the appended claims except as may be required by the prior art.

The present application is a division of application Serial No. 50,962, filed September 24, 1948, now Patent No. 2,582,440.

We claim:

1. A brush mounting for use with rail flaw detector cars of the type which require as a part of their operation the passage of a strong electrical current between spaced points in a rail beneath the car, said mounting including a longitudinally extending support member positioned above the rail and adapted to be raised and lowered with respect to the rail, a plurality of coplanar brush assemblies pivotally mounted adjacent their upper ends in closely spaced longitudinal relationship on said support member, each such brush assembly including a tubular brush holder of substantially uniform cross-sectional shape throughout its length and adapted to receive a brush which initially is of substantially equivalent length, said support member including laterally extending portions forming a plurality of first connection points arranged in closely spaced longitudinal relationship and each located rearwardly of the pivotal mounting for its associated brush assembly and providing lateral clearance with respect to said associated brush assembly, each of said brush assemblies carrying a laterally extending element defining a plurality of second connection points arranged in closely spaced longitudinal relationship and being substantially coplanar with said first connection points, each of said second connection points being located below the pivotal mounting for its associated brush assembly and adjacent its lower end and providing lateral clearance with respect to its associated brush assembly, and a plurality of resilient means each including a compression spring and a stop means acting between said first and second connection points for yieldingly supporting said brush assemblies in trailing position when the support is raised, and resiliently urging the assemblies toward the rail when the support is lowered, said first and second connection points being positioned so that each such resilient means extends in a direction substantially normal to its associated brush assembly.

2. A brush mounting as set forth in claim 1 in which said resilient means are adjustable with respect to the downward forces exerted by said compression spring.

3. A brush mounting as set forth in claim 1 in which each of the brush assemblies includes a tubular brush holder pivotally mounted on the support member, a replaceable rod brush of uniform cross section disposed within said holder, and releasable locking means carried by said holder beneath said second connection point and adjacent the bottom of said holder, said releasable means having its innermost surface in engagement with side surface portions of said brush to accommodate lengthwise adjustments of said brush within said holder.

4. A brush mounting as set forth in claim 1 wherein ggbiipgpgi11t5gnd eggh of said jesilieni means includes 1. 1N 2 3 91 1 2; itslower end ftoione of said ,seco'nd @mwipg paints .apd having {its upper and passing fl ggggh said apertuyed ,hragket with the compression spring telesppped over said bolt and hearing at its upper end pp gaigl bracket and at its lower .end 011 an adjustable put threagiegilypeqeived on the lower end of said bolt.

1 ,5- A hlll h mountin as .set forth in claim 4111 which lsaidu tgpm ans i des an jus ble 510p 0111116 upper sxi of S id bplt ab s id bracket- References Cited in the flle of this'patent 1 NITED SIATES PATENTS 7 Maxim June 8,1880 7 'Kenningfon et a1. Nov. 10,1903 Stiawbridge May-6, 1924 Schaa'keet a1. Aug. 16, 1932 JBillste'in et a1. Oct. 27, 1-937 7: Kaeh ns V- Feb 15, 1949 V FOREIGN PATENTS i Great Britain Oct. 14, 1907 7 Great Britain Nov. 12, 1903 V

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