US2978236A

US2978236A - Crawler mounted loop miner

Info

Publication number: US2978236A
Application number: US588786A
Authority: US
Inventors: Joseph F Joy
Original assignee: Joy Manufacturing Co
Current assignee: Joy Manufacturing Co
Priority date: 1956-06-01
Filing date: 1956-06-01
Publication date: 1961-04-04
Anticipated expiration: 1978-04-04

Description

pril 4, 1961 J. F. JoY 2,978,236

CRAWLER MOUNTED L'ooP MINER Filed June l. 1956 INVENTOR: JOSEPH F. JOY

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ATTORNEY April 4, 1961 Filed June 1. 1956 J. F. JOY

CRAWLER MOUNTED LOOP MINER 8 Sheets-Sheet 2 INVEN TOR: JOSEPH F. JOY

SYM

ATTORNEY pril 4, 1961 J, F` JOY CRAWLER MOUNTED LOOP MINER 8 Sheets-Sheet 5 Filed June l. 1956 mw w y A r mvg-:N Ton: JOSEPH F. .lov www ATTORNEY April 4, 1961 J. F. JOY I 2,978,236

CRAWLER MOUNTED LoolD MINER Filed June l, 1956 8 Sheets-Sheet 4 F Y U Wfl' u (Hgm [gw l u f U O 1 v 4 j l; @L uw L f- G N @im 7i: L99 www i@ x MMR 0 :S- m m. NHV

FIG. 3&2/

ATTORNEY FIG. 2a.

April 4, 1961 J. F. JOY

CRAWLER MOUNTED LOOE MINER 8 Sheets-Sheet 5 Filed June l. 1956 E mw w. N .w n w QN Q mw n S o o H mw .o m Q m Q N m. m Aw o \`.\O\%\@ O l O0 O o o 0 o w I @Em 0 0 um mmm o o f\\ @o Q o I/I/Ilafu@ Q0 if M L KV mm ..-1- immun \\\\\|J\\\H I -rrhh ll\% n@ a n w wm V |.v N-M E Sw uw u wh April 4, 1961 J. F. JoY 2,978,236y

CRAWLER MOUNTED Loop MINER l Filed June l. 1956 8 Sheets-Sheet 6 /g 5 F`|G.4. a

Z 33 :mamma: .sesam F. @ov

ATTORNEY April 4, 1961 J. F. .JOY

CRAWLER MOUNTED 1.001D MINER Filed June l, 1956 mw NQ... QN E April 4, 1961 J. F. JOY 2,978,236

CRAWLER MOUNTED LOOP MINER Filed June l, 1956 8 Sheets-Sheet 8 JOSEPH F. JOY

YM/@gmx ATTORNEY designed for mining coaly or poses'-` of illustrationon t assumev inpractice; l

Joseph FQ Joy, `Fort Pierce, Fla., assigner to,

facturing,Company;1ittsburgh, Pa.; Ya 'corporationo j Pennsylvania M Y Filed tuner, 1956,- serl-No, 538,786?` sciame (ehm-9i.

Thisinventio'n relates to miningymachines andgmore particularly to a crawler mounted nloopwminer; especially otherminerals in :underground mines.

The machine of` the presentA invention constitutesan improvement o-ver those .disclosedin` my copending applications Serial No. 214,242," led"March7,^.l95-l, nowl Patent N6. 2,730,346 andfserial No. 296,325,v niedeiune 30',- 1952, now Patent No. 2,796,246 and is'especially designed for use 'in accordance withthe methodof mining disclosed in my copending application Serial 1No. 296,323`,

filed June 30, 1952 now-abandoned;Y all off these tions being owned by a common assignee.

An object of'thisinvention isV to p-rovldean vimproved applicamining machine! Anoth'erobjectl isto `provide anirnprovedf mining machine of the: type: known v as a loop, cutter having "impro-ved cutting mechanism. Stille 'another object istovproyid'el an`improved4 core cuttmg'and core y United States Patent-A4 f Patented Apr. 4.-, 1951 conveyor in reversed positions as indicated in full and dotted lines. l

The improved mining machine, as shown in the draw7 ings, generally comprises a mobile base 1, desirably a tractor base, havinga frame 2 on which is pivotally mounted on a horizontal transverse axis at 3 a tiltableV frame 4 which ove-rlies `the base frame and extends longitudinally Vforwardly and rearwardly beyond the ends of the base. Carried at the rearward portion of the tiltable ward direction to discharge onto an extensible conveyor 8.

Arranged at-opposite sides of the rearward portion of the tiltable frame 4 are extensible power jacks 10 desirably llluid jackshaving upright iluid cylinders 11 containing Vpistons l2 havingdownwardly extending piston rods 13V engaging the top surfaces of horizontal abutment plates 14 on thebaseframe. VThe tiltable frame4 hasl lateral horizontal plateportions 15 provided-with openings r16 through which the piston rods extend, as'shown/ in Fig. 4.1 1

Themobiletractor base 1 comprises side tread frames 17 about which endless crawler treads-18 arefguided for;

orbital circulation; and the crawler treadsmay be driven breaking means fortafrniningjmachinc. Afurther ob ject to provide4 an improved reversible-loopcutter which may-operate" in substantially right angled'- positions `from eitherv Vside ofthe: machine'thereby toy enable operation of the mach'inein either.of-opposite:directlons along'amine vein. .-A stillfurther `Objectisl to; provide an improvedco'mbined cutting andconveyingf means for-a i 'mining machine and improved driving means' fortheV cutting and conveying'fmeans. Stillanother object: ifssto` `provide anfiriiprdvedV mining machinexh'avingnovel arrangements 'and combinationsjof parts; These and ,other `objects and` advantages ofthe invention will'` however more fully, appear inthe course of the ensuing description.

the accompanying drawings there isv'shownforfzpur- 'Infth'ese drawings:`

L view of theimprovedmining'machine; v l ziw'jFigs,` 2a and'2b, taken together,constitute aside view of the miningmachine shown infFigslafwlbandlc. v Y Figs.v 3a `and 3b, taken together, -cohstittegan end'view hanger support 20 carries a generally rectangularshaped i form which the invention may Figs.fla lb -and le, takentogether,.constitute a plan in any1 conventional manner to effect p rcpulsion, and

steering ofthe machine,

T he reversible core cutting and conveying means S comprises a swivelled support or hanger frame `2 0 (Fig. 6), having aligned vertical shaft portions 21 and 22 jour-r naled in bearings respectively supported by an upper plate 23 and abottorn bearing support 24. These; upper plate and bottomv bearing supports are carried by therearward portionof the tiltable frame 4 as shown. The swivelled cutter and conveyor frame or open-centeredloop cutter bar 2`5-h`avin=g gnideways 26 at the` front andrearward .sidesthereotinfwhich parallel endless cuttngand conveyor chains 27 and 2S are respectively guided.l This cutting 4and conveying frame and the endless Vchains guided thereon and the. associated core breaker means 6 may -be generally similar to those disclosed in rny copending application Serial No..,l94,259,led` November 6, 1950, now Patent No. 2,910,283, also owned by Vthe ,assignee of the'abovej-rnentioned copendingfapplications.

The. loop'shape or open-centered rectangulardcutter and conveyor'frame 25 includes-a generally U-shaped lower frarnef .portion 29 and anrinvertedfgenerally U`- shapedvupper frame portion 30 and the latter portion "Fig, 5 isa horizontalsection-taken'inplanes of line conveyor. j-

Figi 6 isi-a crossis'eetionjtaken onY lines Geldof Figa. fibfandie. i n7Jis1a` vertical section'- showing: the cutter'andfconf j' .-veyor taken onilinje ,of Fig. 3a.

has Vdepending vertical guide portions 31 and-32 received iinfverticalguideways of Vupstanding portionsv 33 of fthe lower frame 29, The frame -portions 33"ca rry` extensible .power jacks 34 desirably of the fluidtype comprising; vertical Huid cylinders sjcontaining pistons 36 having ,upwardly extending piston rods-37 secured at 38 to the :uppergframe portion 30 'as shown in Fig. 6.` Thus when luidunder pressurev is properly Y,supplied vto the jackj cylinders 3'5 the pistons 36jmay be .moved upwardly to *elevate the upper frame portionilrelative toV the lower n ,trarne portion2j9; Aand'bytrapytiirig fluid in the cylindersjj Tthe" ltlis maybe lirrnly locked in' adjusted po'sitionf Any `dmvnfviial; ,Confrollvfilvmeans maY bspw/ide@ .fOr

g the ow of `pr essure,uid to` and theventing kgear 72 .is a smallf spur vrgear 74 chain acts as a cutter chain whilegthe rearward chain acts as a conveyor chain, as disclosed in my copend- No. 214,242 above referred to. in the loosely hanging or looped ing application Serial There is sucient slack cutting and conveying chains is in its lowered collapsed position (Fig. 3b) adjustment in elevation of the loop frame is permitted, as above described, and it is also common practice to provide some sort of ,automatic take-up for the slack in the chains when desired. The swivelled support 20 for the loop bar may be swung about its pivot Vto locate the cutting and conveying chains and the core breaker means in operating positions at either side of the machine, in a manner to be later described in detail.

The means for swinging the-cutter frame horizontally about its pivot may assume various forms ybut herein, for illustrative purposes, comprises oppositely acting extensible power jacks 42 and 43 desirably of the fluid type comprising parallel reciprocable uid cylinders 44 arranged closely side by side and containing pistons 45 having oppositely extending piston rods 46 secured at 47 to the frame 4. Carried by these reciprocable cylinders are guide sheaves 48 and 49. A cable 50 is attached at its ends at 51 within a circular member or disk 52, and is formed integral with the upper shaft 21 of the swivel hanger frame 20 and the opposite strands of this cable extend from the opposite sides of the circular member 52, around the sheaves 48 and 49, and' is secured at 53 atrits intermediate portion to the frame. Thus when uid under pressure is properly supplied to the jack cylinders one strand of the cable may be drawn in while the other is payedv out to effect turning of the circular member 52 together with the swiveled hanger frame 20 about its pivot Athereby to swing the loop cutting and conveying chains and the associated core breaker means from one side of the machine to the other. When fluid so that when the loop fratrieV 4 The chain sprocket 77 engages and drives the rearward endless conveyor chain 28. It will thus be seen that the motors, through the gearing above described, effect drive` of the cutter chain 27 at a relatively high cutting speed and effect drive of the conveyor chain 28 at a relatively' low conveying speed. The chain sprocket 65 is jour# naled on the shaft 62 and has its hub secured as by screws' 78 to a relatively large spur Rotatable with the gear 80 is a relatively large spur gear 82 identical in size to the spur gear 72. During drive of the chain sprocket 65 at a relatively high speed the gears 79, 80 and 82 merely idly rotate.

When the cutting and conveying bar is swung into a right angle position at the opposite side of the machine as indicated in dotted lines in Fig. 10 the sprocket 77 is directly clutched to the shaft 60 for drive at a relatively high speed and at that time the then forwardly located chain 28 serves as the cutter chain and the high speed sprocket 65 is driven at a relatively low speed through the gearings 71, 82, 80 and 79 for driving the then rear- V wardly located chain 27 which then acts as a conveyor is trapped in these swing cylinders the parts'may be rmly held in adjusted position. Any suitable control valve means may be provided for controlling the flow of pressure AViiuid to` and the venting of iluid from the swing cylinders.

The driving means for the loop cutting( and conveying chains 27 Yand 28 may also assume various forms but herein, forv illustrative purposes, comprises a pair of motors 55Y (Figs. lb and 5) carried Vby the tiltableframe 4 and operating 'in' unison,'the motors having parallel shafts 56 (see also Fig. 4) extending longitudinally of the machine. Securedto the parallel motor shafts 'are spur gears 57V meshing with and driving a central spur gear S8. SplinedV at 59 to theV hub ofthe spur gear 58 is a coaxial shaft 60 which is in turn connected as by a key 61 to an aligned shaft62 suitably journaled in a gear housing 63 carried by the tiltable frame -4. The shaft 60 is directly connected by a conventional sliding c lutch 64 to a chain sprocket 65 ywhich engagesand drives the cutter chain 27. The shaft 60 Ais shiftable axially by a power device 66 which includes a fluid cylinderl 67 containing a reciprocable piston 68 havingits piston rod y69-rotatably connected to the shaft. Thus when fluid under pressure is properly supplied to-'the cylinder the shaftrinay be moved axially selectively Ain either of opposite directions. Anysuitable control-valve and venting of fluid from the cylinder.

.with a larger spur gear 72 suitablyjournaled'jon avshaft ,'73 'supported within the gear housing. g Secured to the meshing with avr'elatively Ylarge spur gear "75 rigidlyv secured as by screws to thehubgf Va 'chain' sprocket 7,7`suitably journaled on the 7 shaft 62.

chain at a relatively low speed. The manner of trans-- posing the parts to effect reverse drive of the chains willi later be described.

A detachable pin 81 is receivable in registering holes'l 81 on the swingable frame 20 and the lateral plate por-l tions 15 for locking the loop cutter in either of its right angle positions about its pivot (Fig. lb) at either side of the base.

Now referring to the core breaker means 6 it will be noted that supported by a transverse frame 83 rearwardly of the loop cutter and conveying bar is a series of parallel breaker wedges 84 arranged with their axes in a cornmon horizontal plane and extending within the open center of thecutter and conveyorbar or loop frame. The

n transverse frame 83 is detachably secured as by screws 85 to end frames 86 carried by the swivelled hanger frame 20 mounted on the rearward `portion of the tiltable frame 4. The breaker wedges 84 have spiral vanes 87 and carry forwardly located drill bits 88. These wedges have their tapered bodies threadedly attached'at 89 to shafts 90 suit ably 'journaled within the transverse frame 83. Keyed tol the parallel shafts 91 are intermeshing spur gears 92 con-- tained within the frame chamber 93 for driving the wedgesy y in unison. Secured to an outershaft 91 is a chain sprocket 94 connected by an endless drive chain 9S to a chain sprocket 96 having a sleevelike hub 97 keyed at 9,8 to the rearward end portion of the shaft 62. Extending downwardly from the transverse frame is a transverse guard plate 99-for retaining the dislodged mineral in the path of the rearward conveyor chain as shown in Fig. 7, and a troughlike frame 100 extends transversely across the rearward portion of the frame 4 to provide a longitudinal continuation of the guard plate 99. This troughlike frame 100, as shown in Fig. 3b, is desirably secured as by screws 101 toV a substantially semi-circular portion 102V (Fig. 1b) of a troughlike'conveyor frame 103. j

The conveyor 7 comprises an endless chain 104 carrying lateral flights 105 which travelalong the troughlike passageway 106"provided by the frame 103. The rearward portion of the endless conveyor travels beneath the inner portions of the cutting and conveyorV chains as shown in -Fig. 6, rand inthe reversed positions of the cutter and conveyorbar the front cutter chain moves along troughlike frames 107 carried by the hanger frame 20 and projecting laterally from the `side'siof the conveyor frame. The rear conveyor chain travels in troughlike passageway 108 vpovided by the detachable frame '100 in the reverse positions of the bar. lThus the rear conveyor 'chain,conveys, in either reversed position of the bar, the

dislodged mineral .laterally'rto 'dischargelronto the conveyor V7 .and the dislodged mineralis 'conveyed forwardly lengthwise ofLthe, machine by theconveyor'7 todischvar'ge onto .the extensible conveyor 8^(Fig. T0).

gear 79 meshing with a snralls spur gear likewise suitably journaled on the shaft 73..-

agavaas'e Ibar hangerA frame' 20 about it-s` axis to locate thev bar in` a`v substantially-wrightangle position at the-opposite side of the machine `frame. The frames' 83 and 100 may then be replaced. Thefshaft 60 (Fig. 5) may thenl be shifted axially to` the' left"` to disconnect the clutch 64 from thechain sprocket 65. The sleevelike hub 97 of the sproekethiiy may thenibe detached from the shaft 62 and the later may be disassembled andturned end for end'nd replacedfin its reversed psitirrwithn Vtln'rgear housing. The slee'velike'sprocketsliibA 9-7Iis'ftlen attached to the ppo'st`e`edf` ofthe shaft` 62 and theclutchr 64 may be shifted axially to connectthe sprocket-7,7 thereto lfforlhi-gh speed drive in ythe reversed? pestionofl the shaft 62:-r The gear 67 4meshes with the gear 82 of the low speed? drive for thesprocket 65A so thatthe' endlesscutterchain 27 may' then be 'drivenrat a relatively` low conveying' speed. The transversewedgefcarrying frame l83 and the guard 99l are then attachedtothe rearward portion-of the tiltable frame 4at' the opposite side of the loop bar with the-.breaker'wedges projecting forwardlythrough the loop chain 27 which at that time acts' as a conveyor chain. When' the parts have' been transposed the drive chain 95 may be Yreattached to the drive sprocket 96.

vThe general modefof operationofthe `improved loop miner is as follows: The machine may be trammed about the mine under the propulsion ofthe endless traction treads 1-'8 of the crawler' base ,and the treads may be controlledin Va conventional manner to effect steering of the v machine.- During tramming4 the combined cutter andconveyor-y bar and thetcor'e breaker Wedges may b e swung f horizontally about the bar pivots by the swing cylinders 44? into a'transport position wherein it extends generally lengthwise of the machinethereby to facilitate movement ofthe machine through the relatively restricted and sharpl ly curved passageways of an underground mine.Y When the working place is reached, the cutting and conveyor bar may bei swung? intoVV the substantially right angle position shown in Fig. 1.0 and the'removable and transposable parts may be assembled on the machine with the cutting and conveyor chainsV 27 and 28 and the breaker wedges connected to their drives. The motors 55 may then be operated t'o effect drive of the forward cutter chain^27 `at a relatively high cuttingVV speed and to effect drive of the rear conveyor chain 28 ata relatively low conveying speed. When the loopbar isproperly positioned at the end of the working `face theconveyor 7 isconnectedto its drive and the crawler treads-maybe operated to propel the machine-at a relatively low cutting speed along the face of the mine Ivein.The front cutter chain, as the machine advances, cuts out atcore of mineral of generally :rectangular shape (Fig:` 6) and" as the -core is formed the breaker wedgespenetrate and dislodge-the core. The dis- 4lodged A mineral is receivedy by the rear conveyor chain 28 "and isconveyed" laterally along the Vtrough-like guard plates to discharge onto the conveyor 7 by which thev dislodged mineral is conveyed forwardly lengthwise of the machine to. discharge onto the extensible conveying Y means 8 (Fig. 10). If it is desired to adjust the operating height of the loop cutter and conveyor, `fluid under pressure may be suppliedto Vthe-fluid cylinders 35 to move the pistons 36 upwardlyy thereby to elevate the upper U-frame of theY cutter and conveyor bar.` In' Pig. 6 the bar is shown in `its lowermost collapsed position and in Fig. 9 the bar is shown in its uppermost elevated position, and there is sufficient slack in the chains to permit such adjustment.

The breaker wedges-may penetrate and dislodge .the core` irrespective ofthe height of the latter and in any adjusted position of the loop bar. The front cutter chain may cut and the drive shaft and sprocket parts are dismantledV and turned end for end on Vthe gear housing and when the bar is` in its reversed substantially right angle position the parts are transposed' and reassembled on the machine to permit-reverse operation of the machine.

.Fluid jacks 10i-may be operated at' will to effect tilting of the frame 4v about its pivot to enable the loop cutter and conveyor chainsto follow thet contour of-an uneven mine floor or rolling bottom in a' well known manner.

As a result of'this" invention an improved crawler mounted loop miner is provided having improved reversible loop cutting and conveying means disposable in substantially right angle positionsy at' either side of the machine to enable operation of the latter in either of opposite directions along the face of a mine vein. By the provision of the improved power operated elevating means operatively associated with the adjustable loop cutting and conveying bar parts the operating height of the bar' may be varied to accommodate itself to mine veins of varying heightsas desired in' an extremely elficient manne-r. The improved core breaker means is mounted and arranged in an improved manner with respect'to the cutting and conveying bar and is effective to dislodge the core of mineral irrespective of the effective operating height'of the baror the size of the core. The improved driving means for the reversible cutting and conveying chains and the core breakerwedges including the detachable and transposable parts render the machine Vreadily reversible in a relatively simple manner. The improvedmachine is not only relatively flexible and effi- `cientin operation but is also simple and rugged indesign,

' be modified and embodied in various other forms without departing Afrom its spirit or the scopev of theappended claims. Y

What I claimV as new and desire to secure by Letters 'Patent is:

. 1. In a mining machine, a support, an open-centered core cutter for cutting out a corel of mineral from a solid mine vein, transposable means for mounting said "core cutter to extend laterally at either side of said support, and-,core breaker Ameans carried by 'said mounting means and extending in parallelism with said core cutter at the trailing side thereof for penetrating and dislodging the core in either position of said core cutter, said core breakerrneans comprising a transposable transverse frame disposable on said mounting means in parallelism with said core cutter rearwardly of the latter in either position of the core cutter, means for transposably mounting said transverse frame on said mounting means at either side of said core cutter, and core breakers carried by said transverseV frame and projecting forwardly within said core cutter into engagement with the core for penetrating anddislodging the latter in either position of said core cutter.

2. A mining machine as set forth in claim l wherein conveying means is carried by said transposable mounting means for said core cutter and is transposable with Y said core cutter at either side of said support for con- I veying away the dislodged mineral, said conveying means disposed'intermediate said core cutter and said transverse frame 'in parallelism therewith in either transposed posi tion thereof and extending beneath and movable relative to said core breakers.

3. A mining machine as set forth inV claim 2 wherein a guard plate is carried by said transposable transverse frame beneath said core breakers and extends downwardly at the trailing side of said conveying means in either transposed position of said core cutter for contning the dislodged mineral to be conveyed in the path of said conveying means.

4. In a mining machine of the character disclosed, a support movable in either of opposite directions along .the face of a mine vein, a loop'cutter bar having an open center, mounting means for said bar on said lsupport and adjustable relative to the latter, saidbar being disposable laterally of said support at either side of the latter, said bar providing guideways at its opposite sides, endless loop chains guided for orbital circulation along said guideways respectively, and'each carrying cutting elements whereby either chain may serve as a cutter chain depending on the direction of movement of said body of said support along the mine face, the cutter chain as said support moves along the mine face cutting out a core of mineral from`the solid vein, transposable breaker means attaehable to said mounting means and disposable with respect to said bar at either side thereof, said breaker means extending in parallelism with said chains at the trailing side of the rearward chain which then serves as a conveyor chain, said breaker means at either of its transposed positions having breaker elements extending within the open center of said bar to engage and dislodge the core, said chain which acts as a conveyor chain moving the dislodged mineral in a lateral direction in either position of said bar, and means carried by said mounting means for attaching said breaker means thereto in either transposed position of said breaker means.

5. In combination, a support movable in either of opposite directions along the face of a mine vein, core cutting means having an open center and operating Vto cuta core from a solid mine vein during either direction of movement of said support, means for mounting said core cutter means on said support for transposition into reversed positions relative thereto, core breaker means carried by said mounting means and transposable to positions at-opposite sides of said cutter means, said corev breaker means located rearwardlyrof said cutter means during either direction of operation thereof and comprising penetrating and breaker elements extending longitudinally within the open center of saidv core cutter means for penetrating and breaking the core, means for selectively attaching said core breaker means to said mounting means at either side of said cutting means, said cutter means also having a conveying function, a transposable guard beneath said core breaker elements for confining the dislodged mineral in the path of said cutter means during its conveying function, and means for selectively attaching said guard to said mounting means at either side of said cutter means so that it always trails the latter.

6. `In combination, a support movable in either of opable with said cutter mounting means and disposable rearwardly of said cutter in either substantially right angle Aposition thereof, and means for attaching said core 'breaker means to said mounting means selectively at 'either side of said cutter.

7. A combination as set forth in claim 6 wherein said cutter also has a conveying function and a transposable guard is attaehable to saidmounting means selectively at either side of said cutter in adjacency to and below said penetrating and breaker elements of said core breaker means. f

8. In a mining machine, a support, an adjustable open centered'core cutting means variable in height for cutting out cores of mineral of dilterent heights from a solid mine vein, means for pivotally mounting said cutting means on said support to swing horizontally relative thereto into operating positions at either side of said support, core breaker means carried by and swingable with said pivotal mounting means and having penetrating and breaker elements extending longitudinally within the open center of said core cutter means for penetrating and dislodging the core from the solid irrespective of the adjusted height of said cutting means, said breaker means being transposable and means for attaching said breaker means to said mounting means in either transposed positionthereohsaid core cutting means being reversible and said mounting means being swingable to locate said cutting means in cutting positions at either side of said support, and said core breaker means being transposable and having means for selectively mounting the same Aon said pivotal mounting means at either side of said core cutting means at the trailing side of the latter.

References Cited in the tile of this patent UNITED'STATES PATENTS 1,445,085 Joy Feb. 13, 1923 1,778,298 Levin Oct. 14, 1930 1,824,945 Cartlidge Sept. 29, 1931 2,093,448 Joy 'SepL 21, 1937 2,189,670 Lewis Feb. 6, 1940 2,291,633 Joy Aug. 4, 1942 2,562,841 ComptonV July 31, 1951 2,730,346 Joy Jan. 10, 1956 l 2,753,169 vJoy July 3, 1956 FOREIGN PATENTS V 631,099 Great Britain Oct. 27, 1949 663,3244 Great Britain Dec. 19, 14951 677,065 Great Britain Aug. 6, 1952 724,636 19,55

Great Britain Feb. 23,