US1629502A - hitchcock - Google Patents

Description

May 24, 1927. 1,629,592

H. K. HITCHCOCK APPARATUS FOR GRADING ABRAsIvE AND APPLYING SAME TO CONTINUOUS GRINDING SYSTEMS Fled Nov. 3, 1924 4 Sheets-Shes?r l all 35 32P 35 a7 y 24 K. HITCHCOCK APPARATUS FOR GRADING ABRASIVE AND APPLYING SAME T0 CONTINUOUS GRINDING SYSTEMS May 24,1927.

H, K. HITCHCOCK GRINDING SYSTEMS I5, 1924 4 Sheets-Sheet 3 APPARATUS FOR GRADING ABRASIVE AND APPLYING SAME TO CONTINUOUS Filed Nov.

1 1.629 502 May 24 927 H. K. HITCHCOCK AFPARATUS FOR GRADING ABRASIVE AND APPLYING SAME TO CONTINUOUS GRINDING SYSTEMS Filed Nov. 5. 1924 4 Sheets-Sheet 4 w/rNsaaEs my .HAilallll'.R/II K. HITCHCOCK, OF".E ITT SBURGH, PENNSYLVANIA.

APPARATUS :FOR GRADING Application tiled November n The invention relates to apparatnsior surfacing sheets otmaterial. suchus glass, marble,y and the like` by subjectingr such material toa seriesof grinding oltierations` with theuuse 'of abrasives 0i successivelyfiner and'iiner grades. The'inrention .hasto do particularly with the means for supplyingr the grinding machines with the abrasive, ordinarily sand. -Which is graded ivhilegin suspension in. a liquid, ordinarily Water. and is supplied to the 4,f ,ifrinding machinesmxed .n'ith suoli liquid. Y

One object ofthe invention is to provide. a. system having all ofv its partsin duplicate l5 andso arranged that both sets ot parts vwill normally be iny use. butso designed that in case either half, orfany part thereof, of'the abrasive supply system is shut down orinrapacitated from any cause, the entire grinding system can be `supplied with abrasive from the remaininghalf of'tlie/-abrasivc-supply system,` the capacity each half vbeinp,l sutlicient for this purpose.

A further object is-jto provide a. duplicate system tor supplying abrasive to two long series of ,grinding machines in which .the machines of each series 4act in 'succession on thesurface `beingground. and which supply system insures uniformity in the mixture ot abrasive supplied to corresponding.;r parts oil the two series and is so arranged that each series of grinding machines issupplied with abrasive from both halves oi. the du'pli* cate supply system. A

A further object is to` provide an abrasive supply system whereby a. long series of `grinding);.machines is-supplied from n.' central grader and .in such-manner that ,the supply of abrasive to the more remote machines is as W adequate and uniform as' it is to the close-by machines, andivhieh system is so arranged that the entire series of griudingvmachines can he .kept in operation notirithstanding temporary clogging or stopping' .ot indif vidual conduits and distributingmeans between the central grader and the grinding machines. Y

A furtherobject is to providean abrasive supply' system whereby a long 1 series of ""ii grinding' machines 4actingr in succession 'on the surface beingv ground can be successively supplied with abrasive oi.' progres'sivclyfin-A creasing fineness, and in which each machine is supplied with onlyV one and unito-rm grade oi abrasive, and which system isso arranged nazisme am) APPLrINGsAMn ro Giannino SYSTEMS.

1,629,502 PATENT; OFFICE. i

CONTINUOUS:

a, 1924.-` serial No. 747,582.

that the entirepseries of grinding machines can be, kept in operation notwithstanding steppa-goof the abrasive supplyv from the central-grader 'for a limited period.

'p Other objects and advant-ages lof `the invention will appear from the detailed description hereinafter followil'i".` 1n the drawings the invention is shown as .embodied in an apparatus for effecting a continuous or straight-away grinding operation in which the sheet; oi. glass orother l.

material whose-surface 1s to'be ground is carried progressively across av series ofgrindino machines which, in succession,- a-re supplied with finer and `finer grades of abrasive, and in .which the abrasive is divided in suspension in a. liquid into grades-according to fineness. and in` which all. parts'are in duplicate and so arranged that normally beth series of `grinding machines are'supplied with.,abrasive from bothha-lves ofthe grading'system, but in which either hahc Lot the abrasivesupply system can berutilized to supply both series of grinding'machines.

In the drawings Fig. 1 is a diagrammatic plan vview of suiiicientportion of the tem to illustrate all of its necessary elements; Fig. 2 is av diagrammatic longitudinal verticalsectional vieu7 taken substantially on the line 2-2, Fig. l; Fig; 3 is a plan View' of the means, lying` substantially below the plane 3 3, Fig. 2, for returning the abrasive mixture discharged from the grinding machines toI the gradingsystem; Fig. 4 .is a diagrammatic transversevertical section taken substantially on'tlie line i--LL Fig. 2, except for thefresh sand supply reservoir Whichis in advance o said section plane; Fig. 5 is a vertical sectional 'view through one of the secondary graders; Fig. 6 isan enlarged view ofthe upper portion thereof and illustrating the meansfor blowinglout the supply pipes in case ofclogging; Fig. 7 is a plan view showing a modification of the connections between the sumps and the primary lgraders; and Fig. 8 is a .detailed-sectional view of one ofthe control valves illustrated in plan inFig. 7.

- The grinding machines illustrated are of v the suspended type of grinding heads or runners and are illustrated in two parallel vseries designated respectively A1, A2, A3, Af, A5, A6.` AT, A8. etc. and B1, B2, 133,134', B5, B, B7, ,13", etc. An actual installation embodying: this invention employs. thirteen grindlli ful

ing machines in each series, butl manifestly the number can be more. or less is desired or found necessary. C and Cb representtbe main grziders-,- and which,4 if desired may be the sole graders for the abrasive, one normally supplying 'the abrasive forth@ series of grinding niaehines and the other the abra-- sive for the'B series off grinding;l machines. Adjacent each contiguous twogri'ndiiig ina'- chines is a dietributir-ig vessel,y said distributing 'veeselsalso being in tivo series, those of one seriesjbeing` designated D1. D2, D3, D?, etc. and those off-the' otherseries-b eintg'; designated E?, E2, E3', E?, ete. The distributing vessels-o1 the tivo series arearranged in alternete 'or staggered relatioii, es shown in the plan view,v Fig. 1, for a` purposeA hereinafter stat-ed. These distributintrvessels. serve as local. reserve .supplies for abrding' mixtures and preferably are constructed to serve as secondary"graders, and. are so illustrated iii the drawings.

Each of' the main graders C and C" is of a: type to seperate the, abrasive into grades; of different fiiienefss while insiispeiision iii Wat-erv by an y'upward flow -at a decreasing; velocity of a iniXLure'otThe abrasive iiiid ivate',feccorcliiig .to a; principle heretofore patented by me, and Vare ot the saine gei'i'eral construction as that illustrated inuiy Patent o.; 1v,056,415 vSti-id 'grading vessels are of Ainverted cone shape; for lthe major portion'v ot"l their heights ,wi'tli a"oylindriczil'jportion und an overiioiv trouggl'i at the topf.' The mixture of Water and abrasive'is introduced through the apices ot the cones, 4through ,pipes 1 and l, respectively, thus producing upward 'currentsn Asaid veesels,`aiid which, diie tothe shape of' the vessels, gradually decreasel in'veloeity, thus causing the abrasive to come-.to a stat-e ot" equilibrium in hori` zontalstrata of di-ti'e'rent fineness,' the coarsest material being at tliebotto'iiij and successive. layers iipivardlv Abeit-ig; of finer end finermaterial. The ii'ii-Xt'ii-reoic iva-ter and abrasive is withdrawn from-:each vessel by a series -o-E open-.endedE pipesv extending .d'oivn vinto" the vessel iviththeir endsteriiiinatingatdifferent -l'e-i-fels,A se that eachfpipe will Withdraw the partieular v,erede existing 'at the-level at' which its open end? terminates. To facilitate reniovaf'l' of' the several with draival/pi-pesfrom the graders C a'iid C saidz pipesvvexteiid 'upwardly and'over 'the tops oi?.- siiid vessels.'4 The number of these Withdrawal pipes for each grader is'tlie sai-ue as the miniber efidistribu'tiiigvessels D?, ete. -and EY, etc." suppliedlby 'each' gra-dei', spe- -i-fiealrl'y thirteen innumber in' iilieaetual installation: referred to. These pipes .are design-ated on' the: draivi thev reference .cherieeters F1', Fi, F3; Fi ete; fortlie pipes leadingfroni the grader CLV to?distribut-in;lr

.ife'sselsfDlg D21, D3, D4, ete., and G, G2, G; etc. for the pipeeleafding fromthegredier 'grinding runners of their respective series.; say to t-lie grinding! iiiii chine-B1'.

sel each series are supplied with successively finer and' liner' grades of abrasive.

The. glass or other iuaterial tobe @ground is laid onA tables', n 'iarke-d. iiud 2" (Fig. t) for t'lietwo series. which travel on parallel tracks 3 and 3" looated irespectivclig' iiiiderheath" the two series of grinding runners. and which will be moved iiiecha-riiealli", continuouslj)i iiiid slowly iorii'ziid so .fis to pass iii Succession "iilidei'uezitii, the succes ive These tables will 'be coupled in. i'i'iiiii vclosely, so that-'iii effect the operation ifs that of grinding a continuously traveling sheet of glass, b vsiiccessive operationso'lf ii.' number grinders'there-ori. thus progressively reducing the surface of the glass and i'iiiparting a progressively iiier 4:ind fiiier finish thereto.

As already stated. erich oi',- the` distributiiig vessels preferably constitutes a'. Y eeeoiidarv'gradein As shown (Fig. 5) each ot said vessels is of inverted conesliape for the' iiiaj'or portion of i'tsheiglit, siiriiioiinted b v a Gylindi'ieal portion. The. mixture. of water and abrasive coming frein av ii'iaiii grader enters through the top.- as a-t 5, and the upiviird4 current which existsgiii each of euch vessels causes grading of the iil'ii'iisive. iii suspension iii-the iii-atei. int-o Strata ot' varyingiineiiess. the coarse-st being.Y at the botioiu andV siiCcefESi'veIjyv 'ii'ner ,qriid'es toward' the iop.

Dipping into eiichsuch vessel are u iiuuibi-rofopen-e'nded pipes teriii-iiiziti'ug :it different levels therein so as to ivi'i'lidraiv troni said cone abrasive offdift'ei'ent ii'iieiiess. illustrated, each secondary grridfer provider! with four withdriwal' pipes. tivo long! onesand tivo short ones, the ifoiiiiei of' which withdraw a relirtivclv Coarse. grade `while the latter u'fithdrauf a rel'fitivelv .ti-iii, grade. One

of tlieloiig pipes, `for iiice that' iiiiirlefl 6"; leadsl to the grinding machine ot the. series belonging to the secondary Qi-ader. iiiidei' consideration` sii-y the grader D1'. iiliiwh is oiiy thesid'e of' smid grader toward' the. end from which theglass to be froiiiid is couiing in, sa-y to the u'riiidiii table A?. ii-'l'iile the other long pipe, ii'izifr-llred' G". leads to (he corresponding-grind'ing iiiiirliiiie of' the other One ifi the next 'succeedinggriiidiiigx iiiaehiiie o series ediaeeiit the seconda i' iiiider consideration, sev' to the errinuu iiiichiiie A?, while the other' shortpipeii'ifirked 7"e leads to' the c'orrespviiiidiilu:` Qrindingr inn rhiiic of the; other series'of grinding; iiiach-iues. say to-tlie-iiiacliine B72'.- Tliis eii'uieai i. ii'ov-nient isifolloived for each uit the secondari' grading vessels'. so that each? 4secondziiv grader supplies abrasive to four gijriiidiiig machines, liv-brie.. each; grinding ii'iaeh'iue is i 'supplied with abrasive from two secondary graders. Thus, the grinding table 15J-' is supplied with the finer crade ot abrasive from secondary grader E1 and with the cours-er' grade of abrasive 'troni secondary grader 'DH from E1 varies only Very slightly troni'the `4coarse grade from D1', table A1 issupplied with abrasive of substantially Athe' saine degrec of l'ineness.y Y-

The arrangement described holds true lor each ot' the secondary gradersyit being; un ders'tood, of course, that `the secondary graders in succession throughout each series are i supplied from the' main ,e1-aders with successively iiner and thier grades ot abrasive, as'V a 4resul-tI o'liulnch each table, notwithstanding' that 1treceives abrasive from two secondary graders, is supplied 'with abrasive ot' substantially the saine lgrade,

and4 the successive V"g1-natuur machines throughout each series are supplied with abrasiveol successively liner grader. 'The secondary -f jradcrs are oi" suchV capacity as to serve .as reserve storage reservoirs tor the abrasive, so that` the grinders can be kept in continuous operation even though the supply' from the mainV grader-she entirely discontinued Jfor a'liinited time. Also, by supplying each grinding machine with abra..

sive from two secondary graders, it can; be

kept incontinuous operation even though one. of said graders shouldfilor son'xe. lreason be'shut down.; and hy cross connecting each Seriesof secondary gradersv to the opposite series [of grinding machines all ot the grinding machines can be keptvin operation even though oneentire series oi secondary graders-be shu't.- down. Also, because 'oli this cross Connection iroin yeach series ot secondi aryy grinders-tothe opositc series ot: gzrimlin-oI machines, part of t 1e abrasive coming; vfrom eachV of the main graders passes over to the machines supplied :troni the other primary grader. In this way an in(ermingrliiig.;v and bett'eryblending oi t'liofalirasivo is secured, thus insuring' substantial uniiorinity ol the .grades ot abrasive supplied to the two 'series .of grindingmachines, with a. resultant uniorniity of finish ot. the dass by the two series ot.grinding machines. h

The mixture. o't' 'water and abrasive thrown oit' by the grinding' machines is -pgathered 'in splash troughs arranged, at both' sides ol both series ol grinding-inachneS, the troughs 'forl the seriesii machines heine-'marked 8- and those *tor the series 'B machines being 4marin-id. S, These troughs` 'are in sections with oppositely sloping hottoms 4for approximately each tour urindin machines. as shown .in Figi 2, and troni the lm'vertpoints'in their hot-,trans drainsfl! and 9, respectively, conduct the drainageto return troughs zlll and lll", respectirely.:` lead-` ing' to. the sunips ll-and l1, trein which Since, however. the` fine grade .connection bet tragrments' 'o thev drainage is returned to' the main graders as hereinafter described. Fie'. 3

lshou's'two return troughs 10l and two rereturn trough Yfor each series of vmachines 'will suice. l l

Each ofthe secondary graders is provided wit-h anoverllowfpipe 12 for carryinvoi the Vexcess water and [ine abrasive. 'hese pipes branch (Fig. et) and con'ueet'to longitudinalA pipes l2 extending alcove the splash troughs, and t'roinwhicli-brauches lf2 extend down into the splash trou'ghsat the points where their bottoms are highest and have their `ends turned in op Josite "directions, as shown in Fig. 9, sot at the surplus water overflowing vfrom the secondary graden; serves to wash out the splash troughs. i i Each secondary nader is also provided in its apex with an outlet 13 which drains to a splash trough, and which outlets are closed by' u'ieans ot rubber or other yvalves l-'l earried on thelowe'r ends o'l vertically movable pipes 15 which supply Water ltothesecondradera in order to producefupwa'rdeurrentsytherein', replace the-water lost throng-) the over-iowa troni thesysteni, and dislodge and wash out any coarse 'sand' which may paclrin the tapices ofsaid-vesse'ls. Y' 'To this endeach of said pipes 15 is provided at its lower end with a, hole 16 and has its upper end connected by cross pipe 17 to u longitudinallpipo 1-8 common to the. two series Vout srcoiulary gri-aders and which receives -fater troni a tank i9 supplied with fresh water through pipe 20 and provided with a float 21 and valve tor n'laintaining a constant; level 'olz water therein.- Theoverliow water and also the drain water and abrasive coining' 'troia-the secondary graders and entering the splash troughs returns to the suinps through the troughs hereinafter referred-to. The return troughs l0" and l0" from the tivo reries'of grinding tables discharge respectively into the suniuis ll and lll. Provision, however, is made :to divert: the water troni either ot said troughs to the opposite sump. This effec-ted "by bringing said troughs side-b side` (Fi-np3) and 'affording neen; the sanieloy means of a d'r\idin, f,rv gateQi and providing the.y return 25D, 'rospoeti'velyr` Hence by opening gate' 2.4 and closing,"l one ol" the' stop gates 25".01 3.5" ull o1" ythe'retglun water can be. diverted `to' one o r the 'other ofthe suinps. The rethe suinps through revoiruur screens E26 QG", i'or lcatching any dirt, and the ,lilie. which eensffaro rotated troni motors 27.2727, and 'jlifeharue todirtpans or bins 2G?.

' Each sump is divided/intothree-coni,

ion

ilo

' sive mixture; there is proyided .connecting pipey etfxleading frompuinp 36 or 37 tothe inlet of gradir and another 'diagonal'pipeOVleading from pump 34 or. to-'grader C". This` moss-'connection en. 'ablcsntlie use olf-,both puni-pso? veither pair., one discharging .to oiieothe,.primary-` Apartments.A by means ef parti-tions 28, 29 :and- 30. These partitionsare of the suspended type, that do not extend entirely tri-the bottoms of the snmps. Partitions 2S and 9.9l extend above the water level while partition 3()x tei-inmates n little below the Water. level. The ret-.urn water enters in the compartment defined by partitions` 23 and 29? and.iscompelled. to travel to the bottoni of the sump a-nd undei'iiea-tl-i thoIm-r'itions in order to enterA the other cou'ipartn'ients in which it flows uixjwardly. 'lhe water and suspended abrasive inthe-other two` coin'- pa-rtnients can tlo-w Jfrom one tothe other over thetopv of partition 30.

Extending' down into theY compartment defnedfbythepartitions 2,9 and 30 ot' each of the'sumps are a pair of witl-idrawal'pi-pes. those-'for the sump 1l l-ieing designated 31. and -3-2 and those for the sun-ip 1lb llie-ine designated 3l" and 32". These witlirflrawal vpipes 'are connected through pumps to the two primary graders and in a. way -so that the mixturewithdrawn from either sump e'anbe discharged into either vrr-ader, or both graders con beisupplied- 'trom the saine sump. .Various arrangementsof connections can loe-made to. serve these purposes.

In thearrlangement Shen-n inFigs. "2, 3 undl the withdrawal 4pipe 315L is connected: to pump 34,. the withdrawal; pipe 3l" is con- Vnected.'to-pump 35; thewithdrawal pipe 32 is connected to pump! 36 'and the withdrawal pipe132" is connected to pump'l?. The outlet pipes 34 and 35 (liiv. v4) from .the pumps 34 and; 35.- respectively, leadv to the pipe.A 1"" entering the apex of the lgrader C,

:ifndtlie `outlet. pipes 3.6 and 37. ironithe pumps 3,6 and 37, respectively, lead to the pipe le, entering the apex ofthe liz-rridcr C". By this arrangement either grader' can he suppliedv with abrasive mixture from either sump, orboth gra-ders can-be supplied'from either oneV or the other sump alone.

l).*Torma-llyonly one of the pulir of' pumps 34- or 35 land one of the pai-rot` puinps36 and- 37 willbo used, the other two being rcserve pumps.l -Toprovide for the cont-ingency of both pumps o'teither. et the above lia-med lpairs becominginopcrative; and still heable to. 'supplyy 'bothg-i'nflers! with abraa diagonal graders and l the other discharging to the other primarygrader. i' .p Fi @"7 llustrates an arrangement .alternative to t-liiit.- .shun-'n' in Figi 3' fon. achieving the same purpose.` 'Ashere shown-the pipes 3la and 3'1" are connected .to the-casing of a lvalve 33* to. Whiolivulvecusing; are also. connected the two pumps 34 sind 35, while the pipes 3%* and 32 are connected to the casing of a valve 33b to which are also con.- uected; the two pumps 36 und 37. The valves-3i-n andl 33t are of the construction .shown in Fi 8, with the rotary valve body provided with a cavity 38 arranged' to conneet. adjacent sump and pump pipes, as for instance. in the' case of valve 339,. connect, in one position of the valve body, sump pipe 3l to pum-p 34. and in the opposite position coi-meer sump pipe 31'. to pump 3,5, and with z metric passage: 39. arranged in' one position to connect sump pipe 3l to pump 35.,

`and in the opposite position to connect sump ing from the series B-grinding machines will enter sump lfl" and be `returned to rriulerv the interchange of. water and abrasive between thetwo sides'tak-ing'l place ,through the cross-connections from each of the secondary grader-'sto a grinding machine on thc opposite side, as here'iiibeforc explained. The cross connectionsbetween the return troughs 10 and 10" and the various cross connections between the severa-l pumps, as heretofore described, are not intended. to eilect interchange of .water and abrasive between the two systems, but are emergency connections to be. usedjin oase one of' the suinps clogs oir-'becomes incapacitated. from any reason, 0r in casezboth pumps ofcither pai-r vbecomes incapacitated.

The pipes 3.4, 3G@ .ii-nd. 37, as well as the. diagonal pipes- 40? and 40" leading from the pumps to the prin'iary graders are each provided: with three-way cocks 47 by means .of which the direct flow through saidpipes can be intenrl 1 1 tecl .and the stream diverted through branchesficonnecting with return pipe t9 leading tothe sumps. This luy-pass connection will he used tti-"prevent clogging of thc system when it becomes lnecessary to start up a newpun'ip. For instance, in ease pump 34 is in operation and it becomesnecessary to shutit down and start. pump 35, the .threeway cock 4f? in the d: seharge` pipe from pump ''willbe set tocormee-t with return pipe 419; so that the mixture drawn byv pump 35 from. the sump will be returned to. its This connectionvw-iltbe maintained until .pump 35 has gotten. up,tofful1 speed,

.and then thethree-way cock 14?? in this discharge pipe will lbe turned to position to iso ill

titl

discharge the mixture into the,.fgrading' cone. Thenthe pump 3ft canv bekstopped, and its three-way cock; turned to closev connection to the grader, without danger of the sand settling and clogging the system.

Each sump is provided with a norma-l overflow-"il and with a lower overflow 42, both leadiiug to a sewer, the latter to be used in case .it is necessary to lower the level :of the pair ot pipes `L5 extending down into the sumps and opening adjacentto these angles., andV Vwhich wash-out pipes are connected throug'hjpipes .4 6 and lnranchesla and 4Gb to: the `upper parts of the vmain graders, said branches being provided with valves whereby when ynecessary or desired. water can be admitted through the wash-out pipes.

Fresh abrasive, such as `green sand, is supplied to the two systems from. astoragre ybin or `bins .which vdischarge into troughs 61 and 51 which in turn discharge into the Vreturn troughs lfrom the grinding' ma-4 chines iuadi-auceof the dividing-and stop gates heretofore described, i'o-wlit, at the points 52 and 52", respectively (Fig. 3.). The supply oi fresh abrasive from the bins to the troughs 5l and 5l is controlled by an automatic feeder, `generally illustrated at 53 (Fig. et) .and which in4 turn is controlled b v the density of the mixture in the main gru-ders. This automatic control, in the actual. installation referred to, is of the type illustrated and described in my application Serial. No. 687.702, tiled January 92, 1924.

Since any feeding Ydevice which is autoniaticall)1 controlled by thefdensi'ty ofthe mixture in the system will answer the purpose, such de'viceis 'onlyindicated aud will not be further described.

In event that the systems become charged with surplus abrasive. the coarsest can be withdrawn, prete ably from the main lgraders Cl .and C", such as by means otvalve controlled outlets 55"'.and 55D near the apices of said graders and connected. to pipe 56 lradinp; to a storage bin comprisiug'one compartment 57 for the coarser abrasive and a second compartment 58 for the liner abrasive 4 which will enter the said second compartment b v overflow .over the partition-59. Each (rf-these bin conunartmeuts issupplied with a i-'alre controlled outlet connected to pipes 60 and 61, Arespectively,which llead to the return troughs 10a and 1'0". A' pipe .62 takes care of the o\-'e1flow from this 'bin-v and also leads to the 'return troughs'. v

The fresh water' line 20 which supplies the tank 19 is extended alongthe two series o'iigrindiug machines, asat (54', and at suitable intervals lis provided with' iiexiblebranches to each'ofwhich is connected a nozzle (i6 which is constructed to be snapped over the Vopen end of a pipe coming from a main gra-der and where it enters the secondary grader, in order to blow out any .obstruction in such` supply 4pipes. due tothe clogging of the mixture of water and abrasive therein. To enable this -to be effected the supply pipes to the seconden-57 graders extend through the tops otV feed hoppers. 67. at 'the tops of said secondary'graders and terminateimmediately inside said'. tops, and said hoppers are open on onecsicle, as at 68, to enable the nozzles 66 to be inserted and snapped onto the ends ot" such pipes (Figs. 6).

One'reason for using a singledistributing vessel or secondary grader for each l'two grinding machines is to, enablerthe 4supply pipes for said distributing vessels tobe larger than would be the case if there were as many distributing vessels as grindino machines, andthus reduce the liability.l oip'such pipes clogging. 'lhe snap-on nozzle arrangement described is an emergency device to be used .in'gcase nevertheless suchsnpply pipes become clogged. K.Another reason for having a single distributing vessel or secondary grader t'or each two grinding` machines. is'thatit reducesthe number of withdrawal pipesffrom each ofthe primary-graders to one-half the 'number oi grinding machines of each series,

resulting in Vless pipe obstruction in the primary graders and thus insuring,l a better andl more uniform grading of the material and aless clogging or banking' of abrasive therein. l

.inthe operation of the system the. surplus water and the mud, that is, the abrasive which has been pulverized to practical destruction, are eliminated in part by the. over i'low pipes 41 from theA sumps and in part 4by. the overflow from the main gra-ders, by

way ot the overliow troughs 43 and discharge pipes e3 leading therefrom. The vnecessary amount ot fresh water to supply the water lost throughthese overflows is-.supplied from tanlr 19 and is introduced into-the secondary graders, through the vertical .pipes 15 therein, and serves both to produce the upward gradingcurrents in said secondary graders, and also to wash out any accumulation or banlringofi coarse sand in the bottomsot-v said graders, through the drain orifices 13 therein. The overflows from vthe secondary graders, and also the drainage mixture therefrom, aswell as the overiiow frointhe excess sand 'bins 57, 58, ret-urns to the system by being discharged into the return trougl'is leading 'from thevvgrinding machines to the sumps. The .required amount'of fresh abrasive tev replace 4thatvwliich has been worn out comes from the storage bin 50'and is introduced into .th e system in the required amount through the vfeeding device referred to .which is controlled by the density of the mixture in .the system.

' The systems illustrated .and described has numerous important advantages. By llavi-ng allot the "parte of the system in duplicate throughout, ,and so arranged that each set of grinding machines can be supplied from both halves of the abrasive grading and supply system, and by giving sollicitant capacity to 'the 'abrasive gradi-ngif and supply system, 'it is poi-'sible to have al of the .parts 'in normal use all' of the time, and also possible to 'keep all ofthe grinding machines in operation 'in the .event the Whole or any part of one-half of the abrasive gradingand Supply system becomes incapacitated for any cause'. It is therefore possible to make the necessary adj'ustineniis, repair.; and replacements, or cure any temporary ,incapacity iu-a part-of the `abrasive lgradin and supply sys- `tem, without putting-suyo fthe grindiugina- A'chines .out of opera-tion or 'interfering in any way with their eflici-ent ope-ration, and is ihereforejpossible to maintain the entire systeni in pro er adjustedand operative 'condition', leach ,i all of the abrasive grading and supply system standing ready to handle the en-tire supply ot' graded :abrasive and sup- .it to l of the grinding machines. yrrespective of the duplicate arrangement -of the system, each halt by itsellf provides an Aeieient and advantageous arrangement' `in `supplying abrasive to Aand 'keeping in con- .stant operationa' long seri-es of grinding machines lacting--successively on the surface to be smoothed and progressively producing a .finer and finer surface thereon. By providing such 'long series of grind-ing nia- -c`hi-1ies-with an abrasive supply system inclu'd-in'g `wplur'ality of'distributing vessels or secondaryv graders suppliedl rom al central primary Wader', and each -otwl-ri'ch distributingfvesseljsor-seoondary graders supplies one or v,more adjacent grin'dmr machines, there is provided'a reserve suppl-,y 'o abrasive and -weter adjacent the poi-nts ot use vthereof,'as -a result of which 'the supplyfof 'abrasive-to -the remote machines' is 4as adequate vand uniform as itis to the near-by machines, u 'mriforni-ifty in themixftu-re is insured which weuldnot other-wise be obtainable, and all -of said machines can be -kept in operation even though certa-in olf said distributing ves- -sels er secondary `graders should beincapacitinted and in need-of repair, and even though tfhe suppl fof the mixture to Isaid distributing vease s -or secondary gradersv should be 15,629, son

shut off for limited periods due Ato the clogging of supply pipes, leaks, necessary repalrs to thepipes,'0r even interruptions in the operation of the central Grader itself.

Ample provisions aremade for keeping clean and in proper operative condition all of the pipes, troughs, and sumps, tor eliminating from the system the surplus Water, mud,.a.nd worn out abrasive, tor supplying the system with sufficient water and new abrasive to maintain approximately constunt the mixture in the system, for supplying each I`table with a substantially single and uni-'form grade olt labras-ive, and for supplyinp,` the successive grinding' machines of the series with progressively line grades oi' abrasive, and-'producing such `an .interchange ot the abrasive mixture between the two halves ofthe-system as to insure substantial like conditions in corresponding part-s in the two halves.

I claim:

1. In apparatus for surfacing glass and lthe Ilike, the combination of two grinding systems each comprising a series of grinding machines adapt-ed to progressively and successi'\'ely surface` the material being ground, separate. abrasive supply systems associated with the respective grinding systems and each comprising` a plurality of liquid-suspension distributing and storage vessels, separate constantly operative means with each system to supply each of said 'v sels 'ivi-th graded a-lnasive, and connections lor 'supplying-eaeh grinding machine with abrasive from adistributing vessel of vits own series and from a distributing vessel of Vthe other seri-es.

2. In apparatus for surfacingglass and thev like, the combination of two grinding `systems-eaeh comprising -a series of grinding machines adapt-ed to reduce lnogres- =sively 'and in succession the surface being treated; n'iechanism for 4continuously l-inoving the material to be surfaced to and through said grinding machines in the respective series i-n succession, separate abru- :Sve supply systems associated with euch grinding system und each comprising; a series of liquid-suspension abrasive distributin-g andstorage vessels adapted 'tosupply abrasive to adjacent ,grinding machines` and 'connections operable to supply each vgrinding machine with abrasive ifroni u distributing vessel of its lown series and from a distributing vessel of the other series simultaneously.

3, Apparatus for surfacing ,class and the like, comprising a. plurality of separate grinding systems each system comprising a series o't grind-ing machinesv adapted progressively in succession to reduce the suri'ace of material being ground. mechanism for continuously movi-ng the material being ground through -each series'of grinding mnmanson shines, separate abrasive suppl y systems associated-respectively with eac-h series-fot grind` lng machinesand each comprising a primary grader, a plurality of storage and distributing vessels adapted toholdthe graded abrasive in'liquid suspension adjacent the grind-A ing machines and each connected tothe primaryI grader of its syst-ems by a selective conduit whereby abrasive ofwdierent linef ness issupplied l'osuccessive distributing)y vessels, and separa t-econduits from-distrihu ting vessels 'oli thew'lili'e'ent abrasive sup.

ply systems whereby each ygrinding machine of each. series is supplied with abrasive 'from distributing vessels oli more than o e abrasive supply system.-

alla apparatus for surfacing alass and the like by a continuous series oi' grinding operations, the combination of vtwo grinding systems each comprising a plurality oi' constantly operative grii'idinp; machines mecha nism for continuouslymoving the material.

to-be surfaced tothe grinding machincsol: each series in succession. separate ahrasire supply Systems associated with each grinding system and each con'iprising a primary com 'stantlv operative `grader and apiuralitv ol `distributing and storage vessels adjacent the grinders an-dconstantly simplicd from the primary graderwith'graded abrasive, and a Vplnralitf)T of Withiilrau-'al `pipes fl'rom each 'distributing vessel.leading` to a grinding. niachine of its own system and 'machine of the other systen1.

5. In apparatus for suriiaaigr glassand the like, the con'ibinat'ion ol? two grinding systems each comprising' a plurality ol grinding machines acting inV succes-son on the material to Vbe surfacethan abrasive snpply. system associated with each le'rimiinar system and each comprising a plurality' oi.

grading vessels supplied in succession with finer and finer grades oit abrasive, with-` drawalpipes from each ori-said grading vessels arrangettl to separately withdraw a fine grade and a coarse `agrade. and connections for conducting;v one ot sind grades to la grinding machine oi its own and the with finer and finer grades ot' abrasive, withdrawal 'pipes'from each oi' said grading' vessels arranged toy separatelyv withdraw aline .oracle and a coarse grade, and. connect-inns for conducting one of said nidades to agrinding-machine of its own series and the other grade to ay grinding machine of the other series. f e

7. In apparatus for surfacing glass and the like, the combination ol two grinding; Systems each comprising a plurality ot' grinding machines acting' in succession on thev material to he surfaced. an abrasive snppl7 s5-'ste1n associated with each grinding system. and each comprising a pluralityl ot' grading vessels supplied in succession. with liner-and liner `ajrades of abrasive, withdrawal pipes iromneach ot- Said' grading vessels arranged to separately withdraw a tine grade and a. coarse ,era-dc, and eonnecF tions jfor comlucting` a part ot' the coarse and a part olg the l'ine `grade to two successive grinding machinesof its ownv series and another part oi" the coarse and another part of the fine gra-de to two successive grinding machinesot the other series.-

A8; In apparatus for surfacing glass. and the like, the combination of 4two gtii'uling systems each con'iprisin'g a plurality .of grinding machines acting` in succession` on the ii'iaterial to he surfaced` .an abrasive `supply system associated/with each grinding system and each comprising` ,aj ,primari1 grader'and a. plurality lot' .grading vessels `supplied trom theI primary gradeeinfsuccession with finer and tinervgrades-oi abrasive, witlulrawal pipes 'from each of said grading vessels arranged to separately withdraw va tine gradeaud acoarseV Frade,.a nd comico! tions for conducting a part loi the lcoarse and a part of the linegrade to two successive grinding machines oii -its kown series and another part o'tv the coarse and another part of the tine grade to two successive irritating machines o'l' the other Series. h

9.111 apparatus ttor surfacingl glass and the like, the combination of two efrindim'e` systems, each coinl'n-isingfa series of grindl ing tables adapte-d progressively and succes siveiy to reduce the sui-Face of material be in iay treatedv and mechanism 'tor continuousb; moving the material through each series (it grinding machines, aseparate constantly upf erative abrasive g'adingsystem asso ted Vwith eaclrgrindingj system andv comprising a sump, return conduits arranged .to return the discharge from said grinding s vstems .selniratelyto the two sumps or4 colli-relively to either sump, a pair of withdrawal pipes' ior each sump` a pump tor eacho't' said withdrawal pipes, and piping and valve arrangementswherehy the abrasive mixture can be returned smultaneonslv andyseparately trom either sump to either grading system, or i'roin a single sump to both grading` systems. i

10, In apparatus for surfacingv glass and the like. the combination of two grinding;` systems. each comprising' a series of grind` ing,V tables adapted progressively and successively vto reduce the-.surface 0i' material 'ming treated mid mechanism -for continuously moving the material through eacli yseries of grinding machines, an abrasive grading system associe-ted withV each grinding;- system, ineens :for returning the disclmigc from euch ot seid grinding systeme to its own grading .sys-tem, zaini conncctic-uis lictween said grading systems whereby ,abrasive material passes from each thereof to lthe .other thereof.

Ell. In app'arutus for .surfacing glass'and the like, the con'ibinatlon of two grinding systems, eri-cli comprising n'series of grinding tables adapted progressively and succosj. sively to reduce tbc-surface of nuitcr'iulbcing treated und inecliunisiu .tor continuously manning the material Vt-llnougli each series of grind-ing machines, un abrasive grading sys- -tem associated will each ,grinding system `ply-ing to each rimary grader oi saidgrading systems sul lcient new abrasive to :innintain approximntelyc-onstant the quantity of :abrasive therein.

12. In'appiiutue for surfacing glass and tlieflike, the combination vof two grinding' systems, each comprising' a, series ot lgrindiuq-tables adapted ,progressively and. successivelytov reduce tlie surface of material being treated and mechanism for continuously Ymoving; the material'through each series lof grinding mnoh-ines,van abrasive grading system associated with euch grinding syst-ein, duplicate sumps, two conduit-s, one normali)y returning' tlie discliargefrom -one grin-ding system to one sum-p `and tlieotlier returning tliediscliar-ge from the other grinding syssystems' tem to the otliersump, means lfor returning "the abrasive mixture `from eacli sump to the grading system from which it. receives the discharge, connections 'between said grading whereby abrasive'- material -passes from each thereof tol-the otlier thereof, und means for independently suppliiii-g,r to enc-li of said retumiconduits sufficient neu' abra- Y. sive to nrieintain approximately constant the quantity of abrasive-1n each lgrader.

1 v13. In api-,iai'atus for surfacing 'glass and tbe-like, by u series of continuous operations, the combination of a, seriesl of grinding ru-n- 'nei-s arranged to'fict in succession ou a slicct to "oe surfaced, grading apparatus comprislnga primary grader and a series of see- 'ondary graders for dividing un abrasive in suspension in a liquid into various grades ranging from coarse to line, means for conducting progressively tiner grades of abrasive to successive grin-ding runners, whereby Lemme the successive Tun-ners produce' a progressively liner und liner sui-luce on tl-ie sheer, and ineens ior supplying suiiicient new .abrasive to maintain upproxin'iately consta-nt the various grades in the prin'iary grader.

lLl. .ln apparatus for surfacing glass .and tbe like, llicI combination of u series o'lf grindiug'i'unners, means Afor continuously conveying the iiliocts to be surfaced to said` grinding runners iu succession, a series.; oligrading series of grinding runners, different ones oi said Grading Vesselsjbcinp;'supplied with 'liil'crent gi-:nice ofnbrasivcfsaid vessels being arranged to divide said abrasive in suspension in li iid. into coiirse and ne grades, and iriciu'isicrsupplying each grinding-runner with a sel'iara'te `grade o'f abrasive from :i iiiv of said gnadinfiyifcssels,

' .fin apparatus tor-surfacing glass and tlielik'mtlie combiimtion of i1 seriesof Igrinding runners,-iueans for cont-inuousl)7 conv-eving tlie'slieets to bcsurlac-ed to saidv ,f1-rind- 1:ig runners in succession, appnratus'for clividiiig un 'abrasive in suspension in liquid into various grades ranging from coarse to inc, a series ot grading 'vessels located ntintervals adjacent said series of grinding runners und iii-ranged to divide the fibrasivc in suspension in liquid into course ,and fine grades, menne for conducting different `redes o'f abrasiveto different, ones of seid grading'vessels, and -iineavus i'or separat-eli' conducting tlie various grades of abrasive from-each oft said grading vessels 'to a plurality of runners. i

1i'. ln apparatus t'or surfacing glass and the like, tbe combination of u series of ,grind-v ing runners, means for continuously conveying' the sheets to be surfaced to saidl grinding runners in succession, zipparatus for dividing abrasive in. suspension in liquid into various `grades reiniging: iii-om courseto fine a. series of grading vessels located at inter- Vula adjacent said series of grindingI runners und arranln -tl io divide' the abrasive in suspension in liquid into coarse und iiue grades', means 'for conducting different grades ol abrasive to different ones of saidv grading vessels, und means for Asupplying each grinding runner with n separate grade ls lo'cnted :it intervals adjacent said sive. in suspension in liquid into coarse and line grades,and means forseparately withdrawing the several grades from each. grad-4 ingvessel and conducting the coarse grade to one of saidgiiiiding runners and-the line grade tol al .succeeding grinding runner .of

the series.

19,. InA apparatus for's'urfaeing glass and the like, the combination of a'series of grinding runners arranged toV act in succession ona sheet to be surfaced, va series of grading vessels located" at intervals 'adjacent said series 4of grindingl ,runners and supplied in succession '-WitliV finer and 'finer grades of abrasi've'andarranged to. divideI said abrasive in suspension in liquid into .coarse and line grades, and means vfor separately Withdraiving the various grades from eacli grading vessel and conducting to each grindinr runner the line grade 'from a preceding grat ing vessel and the 4coarse graclefi'oin a'succeeding grading vessel, whereby the sheet is given a progressively liner and finerl Surface by successive grinding runners.

20. In apparatus for surfacing glass and tliedike, the combina-tion `of a series of grinding runneis arranged to act in succession'on a sheet to be surfaced, grading apparatus for dividing anabrasive in` sus-V pension in a liquid .into various grades ranging from coarse to line, a series o'f liquid.

suspension abrasive distributing vessels located at intervals adjacent said series of grinding runners, means for simultaneously conducting udefinite and different grade of abrasive from said grading apparatus to each of said distributin r,'vesselsI- and means for vsimultaneously conducting 4the abrasive vfrom each'of said ldistributing lvessels to a plurality of runners acting on different sections of glass.

21. In vapparatus for surfacing glass and the like, the combination of a series of grinding. runners arranged tov act in succ-ession on the sheetto be surfaced, grading apparatus lordividing an abrasive in suspension in a liquid into various grades ranging 'from coarse to fine, a. series of secondary graders located at intervals adjacent said series ol grinding runners, means -for'c-o'nducting a definite und different grade of abrasive to each of said secondary graders, said second-V ary graders being arranged to separat-e the abrasive supplied thereto in suspension in a liquid into coa-rse and line grades, and means for separately vvwithdrawing the grades .from each of'said secondary gradei'fsand conducting `the coarse Trade to one of' said 'grinding .runners iandthe line grade to a succeed-l ingv grinder-runner of-tlie series; QQInQappaI-atus ilor surfacing glass and the lilrc,tlie combination of a series of grinding runners arranged to act in succession on' c a sheet to besurfu'ccd, grading' apparatus for dividing an abrasive'in suspension in a liquid into various grades ranging v4from coarse to fine, a series ofisecondary gradersV c located atintervals. adjacent said series of grinding runners,4 means for' conducting progressively finer grades. o f a-brasive to eachV of said secondary graders'. inV siiccession,`.said secondary graders being arranged to divide the vabrasive supplied thereto in suspension in the liquid into coarse and fine. grades, and means for supplying each grinding run- 1 ner witlithe fine grade from a preceding secondary vgrader and, the lcoarse Grade .from a. succee secondary graderfnliereby ,the sheetto be groundgis given a progressively finer-andlfiner surface by said grinding run- 11ers` v f v 23. In apparatus-for surfacing glass and 'the like, the combination of a series of grinding runners, means for continuouslymovingasheet'to be surfacedto said grinding runners in succession, lgrading 'apparatus for dividing an abrasive in suspension iii a liquid into vari'ousgrades, 4-a seriesof secondary grading vessels located at intervals adjacent said series 'of grinding runners, means for separately conducting the ioo various grades vto different ones of said i secondary grading vessels, means-for separately ywithdrawing the grades v,from the secondary grading vessels and conduct-ing the same to different ones of said Grinding runners, means for Vreturning the drainage from said grinding runners to the grading a paratus., means to eliminate the Worn out a rasive from the system,- and automatic means tor supplying sufficient new abrasive to maintain approximately constant tlic `quantity of abrasive in the primary grader.

24. In apparatus for surfacing glass and thelike, thecombination of a series of grinding runners, means for continuously moving a sheet to be surfaced to saidgrinding runners in succession, gra-ding apparatus for dividing an abrasive in suspension lin a liquid into various' rades, a series of secondary grading vesse s located at intervals adjacent said series of 'finding runners,

.means for separately Vconc ucting the various grades to diilerent ones of said secondaryvv g'ading vessels, means for separately Withrawing the grades from lthe secondary Grading vessels and conductinv the saine to Idifferent ones of said grin ing runners, means for returning the drainage from said grinding runners to. the grading apparatus,

ies

means to eliminate 4the: Worn out abrasive. from the system', and means controlled by lagnisrn, grading' nl )priratns for divi ing an abrasive in suspension in n liquid :into various grades, means for separately conducting the grades to.'saidi''grinding niechzinisnna sump, means t0 ret'iirn the drainage from 'salid'grinding mechanism toj said snmp land from said suinl 'to said grading appurritus, means,eohvithi raw abrusiveffrorn the gruding'a.ppxvauatfl 1s, and a loinv receiving4 Suid abrasive land di'slraruingto the snmp.

the like,"th e combination of-grindinw meehanisrn, grading apparatus fordividng an abrasive in suspension in u liquid' into vari-- onsv grades, means for separa-teiy cond'ueting l the grades-:to Said grinding mechanism, a

sump, means to return the drainage .from

said grinding mechanism to Sai'd'sump and 27. In apparatus for Surfacing 'glass and.-

the like by a series 'offeontinuous operations, the combination of ase-ries of grinding' runners arranged to uct; in succession on a sheet to lue-surfaced, n grading appara-tus for dividing an abrasive in suspension in a liquid into various grades ranging from coarse to fine, means 'for conducting progressively inor grades of abrasive to successive grinding runners, whereby' the sue- Cessive` runners produce a! progressively finer and' finerl surface. on the sheet, and means or supplying suicient new abrasive to maintain approximatel constant the various gra-des inthe gra er.

In testlmony whereof, I sign my naine.

HALBE-R'r K. HITCHCOCK.

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