US2696971A - Method and machine for spacing railway ties - Google Patents

Description

Dec. 14, 1954 F. H. PHILBRICK METHOD AND MACHINE FOR SPACING RAILWAY TIES 5 Sheets-Sheet 1 Filed Nov. 30, 1949 Dec. 1 4, 1954 F. H.IPHILBRICK 2,696,971

METHOD AND MACHINE FOR SPACING RAILWAY TIES Filed NOV. 30, 1949 5 Sheets-Shet 2 Dec. 14, 1954 F. H. PHILBRICK METHOD AND MACHINE FOR SPACING RAILWAY TIES Filed Nov. 30, 1949 5 sneaks-sheet s Dec. 14, 1954 F. H. PHILBRICK 2,696,971

METHOD AND MACHINE FOR SPACING RAILWAY-TIES Filed Nov. 30, 1949 5 Sheets-Sheet 4 Dec. .14, 1954 F. H. PHILBRICK 2,696,971

METHOD AND MACHINE FOR SPACING RAILWAY TIES Filed NOV. 50, 1949 5 Sheets-Sheet 5 United States Patent a9] 1 M FHQPAND MACHINE'FOR SB A 59 G 1.1; li e a m Frank.H.PhilbrickJivanston IJl. t aqxiitii imif12$? 13 Claims. (e1. 2845; i)

epplisat s li The ,invention relates 'to under railwayrails.

""fineobject ofithe invention is to provide a machine for expediting the corre'ct' spacing of :ties under the rails. Anothefobjet of the invention is-to' provide a machine which *is adapted to expeditiously correctly space =ties which have been displaced by'railway opi'eratio'nor other fiusesfrom their' corretly spaced: positions unde'i' the machines for spacing ties l he invention consists in the several novel features h einaft'er describd and more "part ularl "defin'ed iby "laim's at the" Fv 1 '31" .v'

zlongitudinal section? the 4 shown "in theirtra'ised positi n '1; one of the tie ngagin'gdevieesb'ein shown? I ig. 4 is a plan view, parts being omitted;

a -.lt lw ted to be driven by the" g ne' fo'rjiirov ding 'a sup- ".1: or compressed air in 1' amps: for the 'opei'atibn {of the spacing and "liftingjde'vices." f The "engine and coin- 7p "ss may "be ofany' suitable constructidn, as well imdefstoodinfithe art'." The wlieeIs'IZI-of the triicliare adapted tot'ra'vel on the fails a of a railvvay-trac'fifor lit" importing the truck and: the mechanismlthereoninto iposition for spacing and lifting the ties b undr 'the i'ails.

j The machine comprises devices for engaging the -ties rinder the rails, positioning the ties' in correctly spaced position from one another and for lifting the tiesragainst bottom of the rails while the l atter are being "secured r the, ra e sr nasi g me h ni Ym ir of oppositelyarrangm eoaeting tie engagingtme'm- 75ers, generally designated 34 and "35 atj each side ofgthe Kna k; tim

of plates Z 7 welded to the sides of a pendant arm 38 for-med: of 5 an I-beam. 'The:v plates 37: of'imembers .34

and are-provided Witheurved abiitments 39'.for 'eiigaging one sideio'fla tie, and hooks 40:for engaging the underside. of l the'tie for. lifting purp'os'es. v

' lfhe upper .end..of eachi'tie engaging member is pivotally suspended-on a transversepinf4l' whichv is supported in at vertically swingingtliftingt beam or frame, generally designated #24, and functions ,asa structure for raisingQand lowering ltlie.t.ie=ngaging rneinbers. The lifting ,beam 4'4 is pivotally supported for vertical swinging movement "on a cross-shaft which is journal-led in bearings fixed-t0 the underside of the'tnuckfiame. andfcompriseslower; I-beam sections at thef'oli'ter :sides 'of .the sills .20'p'rovided with braekets' 46 fixed to the cross-shaft 45; upper, sections 51; a tubular cross-member. 52;-braceibeams'47jand 48 Tbetween tubularmember SZ'Land lower sections ,50, .all r i'gidly.secu'red together by' 'welding to form a rigidstructur'e'; Pins 41 extendthroughbearingLplates142which1are fixed to 'the' innerides of s ections fil'gi Eaeh upper secl on "51"comprises apair of Channel sectionsfixedlysecured by welding to the tubular. cross-member .52 and a-- plate 49 l welded toi'the top: ofsaid .cha'nnel section's. -The arin88iof'each pair of members 34,.35 includes downwardly divergent upper-portions, and plates 37lin- 'clud'e' downwardlytc'onvergentportions between arms 38. Ihe lower endsjof'the tie-engagingwme'mbers are pointed t Y adapt them to" penetratej. the.ballastibetween,,the.ties wh'en,' .saidmembers are lowered to tie-engaging level. Each pair of coactingtie-engagin'g members ligi; .35 is connected 'byi 'a pair of upwardly'eonvergent togglelinksfiz and :6 3'.'i Linkfizisconne'cted by a pivot- 6A to a bracket fiii'ed tofthe? section '38 of member-.354 Each link ,63 is connected by a: pivot pin 66 to a bracket 671011 the *Seotioir 381 f member 34." A pivot pin.68;cohnects..the upper inner end of each pair of 1inl s..62-and.-63; .Each pivot pi-n' 68'eiitends through azvertioal slot 70. in'ia pendant iguide gLT whichlis' fixedly securedlto a section 5 1.of'. .the lifting 'bea'm' ,b'y welding and angle sections 572;." Pin 68 iitends th'rough alr'oller. 7.4 which: travels "in slotl70fo'f the guide-- 71.. Dual'.links"62 and- 63 areprovided a't'each side. of each giiide 'n1embe'r771, and pin.68 extends through ithelinks lat/both. sides. The. toggle-linkage .and ithelpin- 'co'nnectio'nf betweenirthe connected ends of the links.and the rvertical guide for said pin-connection function-.lto produceequidistantswinging Tmovementnof the. members .34 and 35 for' shifting antiincorrectlytspaced-tielaterally to abeiitrali'zedposition between thepivoted tie-engaging member's. ,Theilower ends'of s'lotst:.70 --limit. thetdownward iitoveri entflpin' .68 and limit" the,.'sp'readingmove- 'nient'jof the" 't'ie engagir'igmernbersfi I v 4 a;

Tl1'e"'lifting beam 44 is operable to raise the tie-engaging members into position above tracklevelffor clearance in transporting thelinaehiiie' alongthe track'andito lower said mer'nb'ers 'to tie-engaging level. Themech'anism for shift- "mg the liftingbeamiis' pneumatically operable and} com- "prises a' vertically extending cylinder 75,.apiston" 7.6.slid- "able in'sa'idtylinder-and provided with a vstem 77 to the *upper enact which is pivoted. at 78am arm 7 9"whichi-is2 rigidly 'seciiredbywelding to the tubular cross-member ISZ -Zof the lifting beam. Cylinderv is provided with 'tru'n'nions'f 80 which are Jpi'v'ot'ally "mounted in: bearings mounted on bars 81 which areTwelded' to. andproject for- "waraly from the tran'sv'ersemember 22Iofthe truck "frarnejg'Thepiston '76 is adaptedwto be lifted by com- "PI' ES'SCdaiITO "raise'beam 44 when air is admitted. to the lowe'i-"end' of the 'eylinderand to lower s'aid beam when air is admitted to said cylinder abovethe piston.,-' Any "suitable valve 'means,"-as "'wll understood the. art,,1,and

flexible pipes'm'ay be. used for controlling air to andfrom th entl s of 'cylinder 75. 3 i ii The tiegengaging" members 34 and 35 are pivotally supported "by' p'ins'"41 to'P'e'rmit" them to bezspread apart and flowered at theiside's' oradisplaced"tie .and-"to shift a: tie fibetweerrithem'for" forcingitilaterally under the railspand a pneumatieally operable deviceist'pr'ovided for-forcing theti engaging fmernbers of eachrcoacting pair toward the other *Thisfievicecomprises a -cylin'der 84 which is 30 "fiive't'all supported a't'j85 10111 the bracket 65 "on -i'jnernb'er mam a stem which is pivoted at 87 to bracket 67 on member 34. Springs 88 between the pivot pin 63 and guides 71 are adapted to operate the links 62 and 63 to spread apart the tie-engaging members. When air is admitted between one end of the cylinder 34 and piston 86 they will be operated to force members 34 and 35 toward each other until a tie is engaged by the opposed curved abutments 39. During the movement of the tie-engaging members, the toggle links 62 and 63, pin 68 and guide 71 will cause equidistant movement of said members to centralize the tie and cause it to be positioned in properly spaced relation to the adjoining ties. Any suitable valve means and flexible pipes may be used for controlling the supply and exhaust of air to and from cylinder 84. When air is exhausted from cylinder 84, spring 88 will operate links 62 and 63 to spread the tie-engaging members apart and the lower end of slot '70 will limit the spreading movement.

Devices are provided for locking the truck against movement along the railway rails while the ties are forced into spaced position. These devices are pneumatically operated and automatically controlled by the raising and lowering of the lifting beam 44. The locking devices are supported on a transverse channel bar 90, which is fixedly secured to the lower ends of a pair of suspension bars 91 which are slidably guided in brackets 92 which are fixed to the side-sills 20, respectively, and are raised by the lifting beam. Studs 93 are fixed to the sections 50 of the lifting beam and extend through slots 94 in the upper ends of bars 91. When the lifting beam 44 is lowered, the locking devices are lowered for engaging the tracks and when beam 44 is lifted the locking devices will be raised to clear the rails for transportation of the truck. A locking device is provided at each side of the truck and each comprises a lever 95 which is fulcrumed at 96 on the channel beam 90, an arm 97 which is pivoted at 98 to the lever 95, an aircylinder 99 slidably mounted on beam 90, and rod 100 pivoted to the cylinder 99, and at 101 to the upper end of lever 95 of one of the locking devices, a piston 102 in cylinder 99 provided with a stem 103 to which a rod 104 is pivotally connected at 105 and which is pivotally connected to the lever 95 of the other locking device. When air is admitted to one end of cylinder 99, rods 100 and 104 will be drawn together to shift levers 95 so that their lower ends will abut against the inner sides of the rails 11 and arms 97 Will be pried against the outer sides of the rails. A spring 106 is applied to piston 102 to shift rods 100 and 104, to release the locking devices when air is exhausted from cylinder 99.

The locking devices are automatically controlled to cause them to engage the rails a when beam 44 is lowered and to release the rails during the upstroke of said beam. This control comprises a valve, generally designated 115, which is supported on one of the sills and comprises a casing 117 provided with an inlet chamber for compressed air to which a flexible pipe 118 from a compressed air supply tank is connected; a flexible pipe 119 connecting the outlet chamber in the casing to cylinder 99; and a valve 120 which is adapted to cut off communication between the inlet and outlet chambers and provided with an upstanding stern 121 which projects above the casing 117 and is adapted to be engaged and released during the movements of beam 44. A spring 123 urges valve member 1120 to its closed position. An exhaust port 122 is provided in casing 117 for exhausting air from cylinder 99 through pipe 119 when valve member 120 is closed to release the locking devices. Valve member 120 in its open position cuts off communication between the outlet chamber and exhaust port 122 while valve member 120 is open.

When the beam 44 is in its raised position and the members 34 and are disposed above the roadbed, valve member 120 will be closed to cut off the delivery of compressed air to cylinder 99 and studs 93 will hold the bar 91 raised. During initial lowering movement of beam 44, studs 93, engaging the upper ends of slots 94 in bars 91 will allow said bars to drop until said bars are arrested by stops 91 and the locking devices are positioned to gip the rails a. During the continued lowering movement of beam 44, studs 93 will travel downwardly in slots 94 and section of the lifting beam will engage stem 121 and open valve member 120 to admit air to the cylinder 99 and operate the locking devices to engage the rails 11 and retain the truck against movement along the rails during the tie-spacing operation. During the initial raising movement of beam 44 after a tie-spacing operation, studs 93 will travel upwardly in slots 94 until the beam 44 has released valve member 120 to cut off the delivery of compressed air to cylinder 99 and exhaust air therefrom. The locking devices will then be released by the relative movements of piston 102 and cylinder 99. During continued upward movement of beam 44, studs 93 will engage the upper ends of slots 94 and lift bars 91, beam and the locking devices above track level for transportation of a truck along the track. This exemplifies devices for locking the truck on the rails which are automatically controlled to become operative when the lifting beam 44 and the members 34 and 35 are lowered with the beam to rail-engaging position.

The operation will be as follows: The truck will be movable along the track while the lifting beam 44 is raised, and held in its raised position by compressed air in the lower end of cylinder 75. The tie-engaging members and the locking devices will then be positioned above track level. Members 34 and 35 will be held apart by springs 88. The truck will be spotted on the rails in the position where the axis of pin 68 and the center of the desired correct position of the tie are vertically aligned. When the machine has thus been spotted, air under pressure will be admitted to the upper end of cylinder 75 and exhausted from its lower end to cause piston 76 and arm 79 to lower the beam 44 and force the lower ends of the members 34 and 35 into the ballast with their abutments 39 at the proper level for engaging the sides of the tie. During the initial lowering movement of beam 44, bars 91 and channel beam 90 will be lowered until the locking devices are lowered into position for engaging the track rails. When the stern 121 of valve is engaged by beam 44 valve member will be opened to cause air to flow from pipe 118 through pipe 119 to the cylinder 99. Piston 102 will then be shifted in cylinder 99 and operate rods 100 and 104 to cause the track rails a to be gripped between the levers 95 and arms 97. The truck will then be locked against movement over the track rails. During the downward movement of beam 44 the lower ends of the gripping members 34 and 35 will be forced into the ballast with their abutments 39 at the proper level for engaging the sides of a tie. When the members 34 and 35 have been lowered to this position, air will be admitted to one end of each cylinder 84 to operate piston 86 to equidistantly and positively rock the members 34 and 35 toward each other until the tie is engaged by both of said members. During this movement of said members the tie will be forced into position where its transverse center 4' tralized position in vertical alignment with the axis of pivot pin 68. This insures the desired or correct spacing between the ties. For example, after a tie has been misplaced in the ballast to the position indicated by dotted lines in Fig. l, the lower end of the tie-engaging members while spread apart will be lowered into the ballast as indicated by dotted lines in said figure, air will be admitted into each cylinder 84 to force said members together into the position illustrated in full lines where the tie will be located in its correct centralized position between adjacent ties. In this operation one of the said members will engage the tie and force it towards said position until it is arrested by the coacting member. This correct placement of the tie will occur when it has been displaced to either side of the center between adjacent ties or is not transversely aligned with adjacent ties. The tie-engaging members at both ends of the tie during their operation will position the tie so it will be transversely aligned with, and correctly spaced from adjacent ties.

In some instances it is desired to spike the rail on a correctly positioned tie. The beam 44 will then be raised by delivering additional air into the lower end of cylinder 75 to cause the hooks 40 on the gripper members to engage the underside of the tie between them, so that the tie will be held against the bottom of the rail and spikes can be driven into the tie. After each tie-spacing operation has been completed, air will be exhausted from cylinder 84 and spring 88 will operate toggle links 62 and 63 to spread apart the tie-engaging members so that their lower ends will release the tie and be free to be withdrawn upwardly from the ballast. Beam 44 will then he raised :by :air delivered into the ilower end of cylinder 75 to lift the gripping members to clear the track. During themps'trche-of beam-4'4 studs 93min engage the -.upper 'ends of slots '94 and lift bars 91 and beam 90 after the stern 1-2 1 of valve member 1201has been released to cut off the supplyof :air to cylinder 99 and open exhaust port 122 to exhaust air from cylinder '99 and release the docking dev iceslfrom the track rails, so that the truck will be free for transportat-ion along the track for .a succeeding operation. a

The invent'ion is not to be \understood as restricted to the details set 'forth since-these may be modifiedwithin fihe-scope'of'the appended claims without departing from the spirit and scope of -the invention.

J "Having thus described my invention, what new and-desire to secure by Letters Patent is:

1. A machine for spacing =railway' ties under the rails of a railway trackycompr is'ing: a portable truck adapted to travel on -a track; a lifting structure movably supportedon the truck; means for raising and lowering the structure; coac'ting members supported on the structure for engaging opposite sides "of the tie, provided with lower'ends adapted toenter'the ballast; means for locking'the truc'kon the -ra'ils, said locking means comprising avalve controlled "by the raising and lo'weringmovement er the structure and a pair of' pivoted members operatively controlled by said valve, said pivoted members being disposed on opposite sides of .said track and movable transversely'relative 'to each other in response to actuation of said walve;:and "means for shifting said members and laterally forcing the tie between them into a predetermined spaced relation to adjacent ties and relatively :to the-:position-of the truck on the track.

2. A ma'chine forspacing railway ties under the rails 'ofarailway track, comprising: a portable truck adapted to travel on 'a track; a lifting structure pivotally supportedon thetrucky-meansfor raising and lowering the structure; 'eoactingmembers supportedon the structure for engaging opposite sides of the tie, provided with lower ends adapted to enter the ballast; means for locking the truck on the rails comprising a valve actuated by vertical movement of said lifting structure, a rod connected to operate said valve, a lever pivoted to said rod, and an arm pivoted to said lever, said lever and said arm being movable transversely relative to each other to engage opposite edges of said track when said rod is moved in one direction by said valve, and being disengaged therefrom by movement of said rod in the opposite direction; and means for shifting said members together and laterally forcing the tie between them into a predetermined spaced relation to adjacent ties and relatively to the position of the truck on the track.

3. A machine for spacing railway ties under the rails of a railway track, comprising: a portable truck adapts to travel on a track; a lifting beam pivotally supported on the truck; means for raising and lowering the beam; coacting members supported on the beam for engaging opposite sides of the tie provided with lower ends adapted to enter the ballast; means for locking the truck on the rails, said locking means comprising a valve actuated by vertical movement of said lifting beam, a rod connected to operate said valve, a lever pivoted to said rod, and an arm pivoted to said lever, said lever and arm being engageable with, and disengageable from, opposite edges of said track in response to movement of said rod; and means for shifting said members together and laterally forcing the tie between them into a predeter mined spaced relation to adjacent ties and relatively to the position of the truck on the track.

4. In combination, a truck adapted to travel on a track, a lifting beam supported on the truck, and means locking said truck on the track when said lifting beam is moved to a predetermined low position, said means comprising a valve having a stem engaging said beam movable in response to vertical movement of said beam to control said valve, and a pair of members engageable with opposite sides of said track and operatively connected to said valve, whereby actuation of said valve moves said members transversely relative to said track.

5. That improvement in spacing ties in a roadbed under the rails of a railway truck which comprises: securing in a predetermined spot along the track, a truck equipped with power operable members for moving a tie which has been displaced longitudinally of the track or angularly in the roadbed, lowering the members into the l olaim as roadbed at :the vside's :of the (displaced tie and close to and zhetween the adjacent :ties, and ,equidistantly zshizfting by powerwithe members together and relatively to the truck, whiletheir lower ends -.are :in the ballast, and forcing the :displaced tie laterally until :it .is positioned substantially mid-way :between adjacent ties and-transversely of the rails while :the truck remains stationary.

6. That improvement in spacing :ties :in .a'roadbed :under the rails of .a railway track which :comprises securing in .a predetermined spotalong the :track, {3. truck equipped withtpower operable members ;for moving :a :tie "which has been displaced longitudinally of :the track {OI :angularly in :the roadbed, lowering zthe members into ithe roadbed at the sides ;of the displaced ztie and rclose. T10 and between the :adjacent ties, :and .equidistantly .and :positively shifting by power ;the members :together and .relatively to the :truck, wvhile :their lower .ends :are in the ballast and thereby forcing :the displaced tie :laterally until it vis positioned substantially amid-way ibetween adjacent .ties and transversely .ofxthe :rails .while -.the truck remains stationary.

7. A machine for spacing railway rties .in ithe iballast under the rails of "a railway :track, comprising: ;a :portable truck adapted to travel along the track; means :for locking the :truck :against travel along the track; :a :lifting 'beam on .the truck; a .pair of coacting tmembers pivotally mounted :on :the beam, -over each ,end of .a tie, said members having lower ends adapted lto penetrate ballast and being movable apart 'to enter ballast :adjacent opposite sides of areas between which there is :an intermediate tie and movable toward each :other to engage the intermediate tie, if misplaced, and movable relatively to said truck to move the tie in its-central position between adjacent ties and in parallel-relation to the'transverse plane -of the track; power operated mechanism for lowering the beam to :force the lower ends .of the members into the ballast; means between the beam and *the members for-equalizingthe pivotal:movement'of the members; and power operated apparatus for shifting l-the members so their lower ends will force the intermediate beam substantially horizontally into said central position and parallel relation.

8. A machine for spacing railway ties in the ballast under the rails of a railway track, comprising: a portable truck adapted to travel on the track; means for locking the truck against travel along the track; a lifting beam pivoted on the truck; mechanism for raising and lowering the beam; a pair of coacting members supported on the beam over each end of a tie outwardly of the rails, each pair of members having lower ends adapted to penetrate ballast and being movable apart to enter the ballast adjacent opposite sides of areas between which there is an intermediate tie and movable toward each other to engage the intermediate tie if misplaced and movable relatively to said truck to move the tie into its central position between adjacent ties and in parallel relation to the transverse plane of the track, a toggle linkage between the beam and each pair of members for equalizing the movement of the lower ends of said members; and power operated apparatus for shifting the lower ends of the members substantially horizontally and forcing the intermediate tie into said central position and parallel relation.

9. A machine for spacing railway ties in the ballast under the rails of a railway track, comprising: a portable truck adapted to travel on the track; means for locking the truck against travel along the track; coacting members supported on the truck above the ties, having lower ends adapted to penetrate ballast, movable apart to enter the ballast adjacent opposite sides of areas between which there is an intermediate tie, and movable toward each other to engage a misplaced intermediate tie and movable relatively to said truck to move the tie into its central position between adjacent ties and in parallel relation to the transverse plane of the rails; means for raising and lowering the members; and power operated apparatus for substantially horizontally and positively shifting the lower ends of the members and forcing the intermediate tie into said central position and parallel relation in the ballast.

10. A machine for spacing railway ties in the ballast under the rails of a railway track, comprising: a portable truck adapted to travel on the track; means for locking the truck against travel along the track; a pair of coacting members supported on the truck above each end of the tie outwardly of the rails, each pair of members having lower ends adapted to penetrate ballast, movable apart to enter the ballast adjacent opposite sides of areas between which there is an intermediate tie and movable toward each other to engage a displaced intermediate tie and movable relatively to said truck to move the tie into its central position between adjacent ties and in parallel relation to the transverse plane of the rails; means for raising and lowering said members; and power operated apparatus for horizontally and simultaneously shifting the lower ends of both pairs of members and forcing the intermediate tie into said central position and parallel relation in the ballast.

11. A machine for spacing railway ties in the ballast under the rails of a railway track, comprising: a portable truck adapted to travel on the track; means for locking the truck against travel along the track; a pair of coacting members pivotally supported on eccentric axes on the truck above each end of the tie outwardly of the rails, each pair of members having lower ends adapted to penetrate ballast, movable apart to enter the ballast adjacent opposite sides of areas between which there is an intermediate tie and movable toward each other to engage a displaced intermediate tie and movable relatively to said truck to move the tie into its central position between adjacent ties and in parallel relation to the transverse plane of the rails; means for raising and lowering said members; and power operated apparatus for horizontally and simultaneously shifting the lower ends of both pairs of members and forcing the intermediate tie into said central position and parallel relation in the ballast.

12. A machine for spacing railway ties in the ballast under the rails of a railway track, comprising: a portable truck adapted to travel on the track; means for locking the truck against travel along the track; a pair of coacting members supported on the truck above each end of the tie outwardly of the rails, each pair of members having lower ends adapted to penetrate ballast and being movable apart to enter the ballast adjacent opposite sides of areas between which there is an intermediate tie and movable toward each other to engage a displaced intermediate tie and movable relatively to said truck to move the tie into its central position between adjacent ties and in parallel relation to the transverse plane of the rails; means for raising and lowering said members; and power operated apparatus for imparting positive equalized substantially horizontal movement to the lower ends of both pairsof members and forcing the intermediate tie into said position and relation in the ballast.

13. A machine for spacing railway ties in the ballast under the rails of a railway track, comprising; a portable truck adapted to travel on the track; means for locking the truck against travel along the track; a pair of coacting members supported on the truck above each end of the tie outwardly of the rails; means for raising and lowering said members; each pair of members having lower ends adapted to penetrate ballast and being movable apart to enter the ballast adjacent opposite sides of areas between which there is an intermediate tie and movable relatively to said truck and movable toward each other to engage a misplaced intermediate tie to move the tie into its central position between adjacent ties and in parallel relation to the transverse plane of the rails; and power operated apparatus for shifting substantially horizontally and equidistantly the lower ends of the members and forcing the intermediate tie into said central position and parallel relation in the ballast.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 936,679 Spandau Oct. 12, 1909 976,513 Smith Nov. 22, 1910 1,180,605 Pierce Apr. 25, 1916 1,391,822 Evans Sept. 27, 1921 2,018,129 Jackson Oct. 22, 1935 2,596,823 Richardson May 13, 1952

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