[1]Patented Nov. 24, 1953 2@6602432 UNITED STATES PATENT OFFICE 2,660,432 APPARATUS FOR CONVEY]ING AND STACKING BOX BLANKS Julius E. Wilske, Francis A. McCormick, and Verney G. Pollisch, Alton, IR., assignors to Owens-Illinois Glass Company, a corporation of Ohio Application September 4, 1948 ' Serial No. 47,774 7 Claims. (Cl. 271-68) 2 Our -invention relates to apparatus for receiving blanks of sheet material and conveying, elevating and stacking them. The apparatus as herein illustrated is designed for receiving flat blanks, foldable for making boxes or cartons, con- 5 veying and elevating the blanks and stacking them, and Nvill be described as used for such purposes. It will be understood that the invention is not limited to such use. Our invention provides an apparatus for receiv- 10 ing the box blanlis in fl@at form from a printing and slotting machine, and stacking the blanks on a truck or the like, In its preferred form it comprises a horizontally d;@sposed travelling belt conveyor arranged to receive the blanks, an elevat- 15 ing belt conveyor onto which the blanks are discharged from the receiving conveyor, the elevating conveyor frame being mounted to swing upwardly from a lowered posi.tion in which it is substantially horizontal to an upwardly inclined 20 position, thereby gradually lifting the discharge end as the stack of blanks increases in height, and means for then returning the conveyor to its lowered position preparatory to building a succeeding stack of blanks. 25 An object of the invention is to p@-ovide means bY which the elevating conveyor is hoisted and lowered automatically combined with manual control devi-@es by which the various operations of the receiving and elevating conveyors are under the control of the operator. A further object of the invention is to provide au@omatic i-neans by ,@7hich the receiving conveyor is run a,t a co-,.,nparatively slow speed while the elevating conveyor is being lowered and then @j at a coi,.qparatively high speed during the stackin.@ of the blanks. A still further object of the invention is to provide manually controlled means lay which the elevating conveyor may be inched up or down 40 by the operator for adjusting the height of the discharge end of the conveyor to correspond with the height of the stack at the time of such adjustment. 4;5 Other objects of the invention will appear here;nafter. J.@,eferril'i.- t-- the a-,companying drav@7ings: Fi!@-. I is a side elevation of an apparatus ern - bodying oi.,r illventi@on. 50 Fig. 2 is a fragmentary sectiona'l vie@v at the line 2-2 oi-i Fl.g. 3, show'ng adjacent end portici,is of the r.-ceiving and elevating conveyors. Fig. 3 is a plain viev7 of the apparatus, parts being broken away., 55 Fig. 4 is an elevation of the receiving conveyor and its driving inotor. Fig. 5 is a fragmentary elevational view showing tho adjacent end portions of the receiving and elevating conveyors and the driving motor for the elevating conveyor. Fig. 6 is an elevational side view of the elevat: I ing conveyor and the hoisting mechanism theref or. rig. 7 is a front elevational view of the hoisting meebanism. Fig. 8 -'Ls a fra.anentary elevational view of the upper portion of the elevating conveyor as indicated by the iine 8-8 on Fig. 1. F-ig. 9 is a fragmentary part sectional plan view, showing a corner portion of the elevating conveyor and associated parts. Fig' IO is a sectional elevation at the line I D- I 0 on Fig. 9. Fig. 1 1 is a wiring diagram of the electric motors and their controlling mechanism. Referring to Fig. I the invention comprises, in general terms, a h;rizontal endless belt cbnveyor 12, herein referred to as the receiving conveyor, receiving blonks B fror-q a printing and slotting machine 1.1, a motor Ml which drives the receiving conveyor, an elevating conveyor 14 which receives the blanks from the conveyor 12, a motor M2 for driving the elevating conveyor, a hoisting motor W geared to hoisting drums 15 and operating intermittently for lifting the discharge end of the conveyor 14 step by step as the stack 16 of blanks is built up, and then lowering the elevating conveyor preparatory to building a succeeding stack of blanks. The blanks as shown are stacked on a truck 17. Automatic control devices are provided for reversing the hoisting motor when the conveyor 14 reaches its upper and lower liinits, stopping the travel of the elevating conveyor belts and reducing the speed of the receiving conveyor during the lowering of the elevatin.- conveyor, all as set forth hereinafter. The receiving and eievating conveyors and their motors are mounted on a horizontal base or framework 20. The hoisting mechanism is mounted on a pl@atform 21 supported on an upright frome comprising vertical channel-iron fraine memb.ers 22 and cross-bars 22'. The receiving conveyor 12 comprises a plurality of horizontally spaced endless conveyor belts 23 (Figs. 3, 4 and 5), trained over pulleys 24 on a driving shaft 25 and pulleys 26 on a driven shaft 27. The belt@ are supported on sheet metal strips 28 mounted on cross channelirons 29 attached to
[2]2,660,432 the side frame inembers @10 of the conveyor frame. The conveyor 12 as a whole is carried oli a horizontal shaft 32, and is mounted for tilting niovement frori its horizontal working position to an approximately vertical position as sliown 5 in broken lines -in --Fig. - 1. The - slaaf t,,32 is -supported o;i etandar s@3,3.mounted on-,the-frame@d work 20. Means for tilting the conveyor comprises a hand wheel 34 (Figs. 3 and 4) on a shaft 35, carrying a wdrm 36 running in mesh with a 10 worm gear segment 37 bolted to - t-be :cony@yor frame. The downward tilting movernent--of -t-he conveyor frame is Iiinited ,by -an 7 dj',ustable st@op ,a 42, screw-threaded into a post-.4,3 -position @to its upviard position shown @in -broken LI 5 -lines on'Mg, 5. The hoisting motor 'LA3 -has,driving tonnections -with@the hoisting drums -through @speed -reduction .gearing viithin a gear box 6 2 (-F-igs. -1 and 7), said ,gearing driving the-drum shaft 63 on-.which-7the co -hoisting drunis [5 are @mounted. Cables @65, woun(f on the drums, are -attached -to - trunniqns 166 or posts, bolted to the side frame mem,@bers 67 @of @t-he -elevating conveyor, -a -shortdistance@from IC -t-he :discharge end of the Qonveypr. Rollers 68 lournaled -on the @free -ends of the - trunnions 66 --run--in vertical guideways@formed by g-uide rails ,6,9 --ballted to the upright -frame -members 22. -It will be see@n that with this construction the path 70 gf ljp-,and-@dQwn rnovement , of the,disclxar-ge - end -of.-,the conveyor is appro ately vertical, thereby permitting the blanks B,,as they:aredis-charged from the conveyor to, be built@lato sub,,stantiall vert c,:kl .stacl@s I S. The niotor @,IV13 @ is @75 .,y - i MI which drives the conveyor 12, operates through speedredu@-tion gearina within ,a gear boLx,,30, and sprocket diiving chains-39 and-40, the latter trained over a sprocket gear 41 keyed to@t@he drive shaft 2 S. .T'lae-,elevating convi@yor , 14, which.-Is _siniiiar-in construction to tl-ie receiving.convp:,yQr.12, com1)i7ises endless conveyor belts,4@3 paced horizonta4yandinlinewiththee4onv,eyqr,belts23. The belts, 45,are,trained over pulleys 46 .(Fig. 3) Qn @ a drive shaft 47, and pulleys 48 pna driyen shaft A 9 ,(-Fig. @8) @at the u per or discharge end of 7,the p conv.eyor. Thebeltsare supported on underlying sheet metal strips 51 attached to cross-channel @.bars::52 . forming .part Qf the ,cQnveyor f-rame. The motor M2 which drives t@he co-nve - 14, op,Yqr ,erates through speed reductiqn gearing w,ithin .a@ gearbQx-,53 @,(-Tigs.:3, and 5) an,d sprocket gear chains 54 and 55. 7he ebaiii .54 is trained over -.a,, SproQl@,et w-heel -on a @stub shaft @56 mquiited .@iii-.a-,standard-,57,,..gaid s'@ia@t @l6@ being-in horizqn@ tal alignment with - e,..Shgft:-27,of t4e -receiving .til -.ConveYo,r. !r-lae,@chain-55-istra ined--over.asecond sprocket wheel on the shaft 56, and a. spto!,ket ,Nvheel)58.,keye.d to.the@ drive sh-aft 4,7, of @.the elevating @..@conveyor. T-he :tw.0 sprocket -wheels on ,thestubshaft56,areconnected.torotoLteasa.u-nit. -The -.shaft,-47: is journaled in rock arms:,60 and -6 I x)r - hangers which support the ireceiving end of t,he elevating conveyor. The armr6O is@journaled at one end on the:stub shaft 56@and the arm-61 is likewise jo7,Lirnaled at one end on. a -stub: shaft 46' :in alignment with the -shaft -27. ,The drive @shaft,47 is journoled;in the opposite ends of-the -rockarms,@,60,:61. Thisconstruttionpermits:the -lower,or @receiving- end @of 'the elevating conveyor - to!swing about the axis -of the:stub shafts@ 56 @and @-,56'@during the hoisting and lowering of the @oGn,veyor which swings from its lowered or: horizontal 4 equipped with a brake 59 actuated by an electromagnet z59' which is deenergized to apply the brake when the motor circuit is opened. The conveyor 14 is provided at its upper end with a cross bar 70 carried on hangers 71 pi-Voted t o -- an d:@depending from @@the -.con-vi@yor shaft 49. -The.bar TO @isweighted by-a,metal rod'12 so that the front face of the bar 70 is maintained in a .:substantially vertical plane. The bar serves as _a guard to prevent the discharged blanks from 'ibeing -,carried -back beneath the conveyor and also serves as a guiding means by which the 7-blalits ,4re.aligned on@the stack i 6. The @trunnicrr;6 6 carries a switch operating cam 0 conveyor in its operating :pqsition. -The--mot-or.-I-5 -.,"T@5;:(F@igs.@;6,-and,@9) which actuates an arm 76 Of 1211 an upper limit-switch as the elevator reaches its uppQr -1@anit .of, movement, and a cam 77 which ac-tuates an arm 78 of a lower limit switch when the,-elevator is lowered, as more fully described hereinafter. -The@receiving conveygr is provided at.its discharge-eAdwith-a series of guar4s @80 (Figs.2 and -3) interposed between the belts 23 and @attached to:a -cross -bar -,29 of @the conveyor frame. These gua-rds.-extexid dc)-wnward into position to prevent blanks,B from slipping or boing carried:back beneath the @conveyor belts. to the wiring diagra@m (Fig. 11) the motors and their control -devices receive current supplied through the mains, a, b, and c of a threephase system. The motors are connected 'directly to @the mains. The relay magnet;coils Teceive current through @a -step-down transformer comprising @the -primary winding 8 I connected to @ tb-e mains, b, c, and a -secondary winding 82 to which are ronnected the lead wires or mains @83 a-nd 84. -,The mgtor MI is wound for fast and slow speeds, and -operates to drive the receiving -conveyor at slow -speed while the elevating conveyor;is being lowered and at full speed -while the@elevatingeoni7eyorbelts-arerunning. Eiectromagnet coils 85'and 86 operate @to close -the motor-switches- for fast and slow speed windings respe(itively. Control devices for the motor MI include a push button starting switch -87, a stop switch @88, relay coil .89 -for closing a holding circuit,-and-a relay,90 operative-to shift I t-he motor @connections fro'm-slow-spqe@d to fast spe@ed, alil as - presentlydescribed. ContrGl devices associated with motor M2 which drives the elevatingconveypr belts include_a stop -switch @ 92, starting switch @93, and relay coil 94 for -operating the,,mqtor switch 95. A selector -switch,96 is shif,table from position for manual _control-to a position for full automatic co trol of the-several motors. The hQist@qg.,mQtor NV is reversible. A switch @97whenclosedb itsrelaycoil98,makesacircuit y for @operating the motor in a direction to ho-ist - the -elevati.ng conveyqr. A switch @9 9 and its -coil -100 -control the current supply for running th . e motor in @ the reverse direction. The hoisting movement -of the elevating conveyor is under the control of a tirner device T including a relay @coil 102 -and -switch 103. The timer operates automatically to cause an intermittent step-by-step upward movement of the discharge end of the conveyor. -As the -stack 1,6 of blailks is be@ing built up, the hoisting mgvement of the conveyor is at a rate such that the discharge end of the -conveyor is at iall tinies just ab<)ve the top level of t-he stae -Ixl orde,r -to -permit riialiual control of such hoisting movement, there is provided means for
[3]5 inching the conveyor up or down, that is, - 'moreasing the rate of upward movement or reversing the movement to correspond to the height of the stack of blanks. Such control devices include push buttons 105 and 106 for raising the - conveyor 5 and push buttons 107 and 108 for lowering it in the manner hereinafter described. Operation The operation is as follows- 10 Assuming the motors to be at rest and the elevating conveyor 14 in its lowered position and no blanks being fed to the apparatus, the operator first closes the push button starting switch 87. This completes a circuit for starting the 15 motor MI and running it at slow speed, said circuit may be traced from the transformer main 83 through wire I 1 5, switch contact bar I I 6, wire I I 8, contact bar 119, wire 120, relay coil 86 and wire 121 to main 8,4. The coil 86 being energized, closes 20 the motor switch 122 so that the mbtor StAtts and runs the receiving conveyor i 2 at slo w speed. The closing of the starting switch 87 also completes a circuit for the relay coil 89 which circuit extends through wire 115, contact bars 116 2.-5 117, coil 89, wires 123 and 12-4. The relay coil 89 lifts its contact bar 89a and thereby closes a holding circuit (short eircuiting the switch 87). The operator then presses the, push button 93 for starting the motor AV which drives the ele- 10 vating conveyor. This completes a circuit wh4.ch may be traced from the transformer main 83 through wire 126, stop switch 92, starting switch 93, wire 127, coil 94, wires 120, 125 and a li.mit switch LS to main 84. The coil 94 being ener- 3gized, closes the motor switch 95 and starts t@e motor AV. The switch 95 iiicludes a cbntact bar 129 which closes a holding circuit across the starting switch 93. The contact bar 129 also completes a circuit for the relay 90, which cir4o cuit may be traced from main 83 through wire 126, stop switch 82, wires 130, 131, contact bar 129, wire 132, relay coil 90, and wire 133. The relay 90 being energized, operates to change the circuit connections for the motor Ml from slow 45 speed to fast speed. That is, the contact bar 119 being lifted, opens the circuit through the slow speed relay 86 and closes a circuit through the fast speed rela@ 85 so that the mot(ir switch 122 is opened and the switch i34 is closed, cau8ing 50 the motor to run at high speed. The elevating and receiving conveyors are now both - running, The operator next starts the printer 13 (Mg. 1) so that blanks B are delivered onto the conveyor 12. This may be at a rate such that t-he 5,5 forward end of each blank is a short distance back of t-he preceding blank, with each blank overlapping a number of the preceding blanks. As the foremost blanks approach the discharge co end of the receiving conveyor, the operator throws the selector switch 96 from the hand coritrol p 0sition (shown in full lines) to the automatic control. This completes a circuit through the relay coil II 0 and coil 102 of a timer T. This ci@cuit 65 can be traced from the transformer main 83 through wire 126, stop switch 92, selector switch 96, wire 135, and through coils I 10 and 162 in parallel to main 84. The relays I IO, i 02 being energized, close their switches and thereby make a , circuit for the relay 98 of the motor switch 97. to This circuit extends from main 83 through wire 126, stop switch 92, wires 130, 136, 137 ' switch contact baxs If 1, 103, wire 138, switch 107, wire 139, and wire 140. The motor switch 97 is thus 75 the latter at full speed. . I 6 Closed and the motor AV starts in the direction for hoisting the discharge end of the elevating conveyor. As the hoisting operation is necessarily comparatively slow in order to keep the discharge end of the elevating conveyor just above the upper level of the rising stack of blanks, the timer T is employed to effect intermittent operation of the motor M3 during the hoisting operation and per_mitting continuous running of the motor in the reverse direction while the elevating conveyor is being rapidly lowered. The timer T operates its contact bar 103 intermittently for opening and closing the motor control circuit, the timing (which may be adjustable) being such that the motor only runs for relatively short intervals. The circuit may be closed, for example, for one or two seconds and open for 30 or more seconds. As the timer is a commercial article, known In the art, further illustration is deemed unnecessary' Such a timer, which has been found practical for use with the present invention is the product made by Eagle Signal Corporation, Moline, Illinois, and marketed under the trade name "Flexopulse" process timer. As the elevating conveyor reaches its upper limit of movement, the limit switches LS and LS2 are automatically opened, and limit switches LS4 and LS3 are closed. The opening of the limit switch L.S opens the circuits through the relay 94, coil 102 of the timer T, and relay 90. The opening of a circuit through coil 94 opens the switch 95 and stops the motor AV thereby stopping the elevating conveyor. The opening of the circuit for the timer coil 101 permits the lowering of the conveyor without interruption by the timer. '-rhe opening of the circuit through relay 90 operates to shift the motor MI from fast speed to slow speed, by bpening the circuit for the magnet coil 85 and closing the circuit for the slow speed cbil 86. The opening of the upper limit switch LS2 opens the circuit through the coil 98 of tl-ie motor switch 91, thereby opeiling said switch and stopping the hoisting motor M3. The closing of the limit switches L84 and LS3 esta-blishes a circuit for the coil 100 of the motor switch 99 so that the motor M3 is started in the direction to lower the elevating conveyor. This circuit for the coil 100 may be traced from the main 83 through wire 126, stop switch 92, wires 130, 136, 137, contact bar 112, v,,ire 142, limit switch LS4, switch 106, limit switch LS3, wire 143, coil fol, and wire i4O. The limit switch LS, closes'.as soon as the elevating conveyor starts downward, being held open only while the conveyor is at its uppermost position. Me liniit sw4ltch LS4 i@ only held closed momentarily, while the conveyor is in its upper postion, to permit a circuit to be made through the relay 10,f; for closing the swite-h 99 and starting the hoisting motor M3 in the direction for lowering the conveyor. lvhen the motor switch 99 is thiis closed, a contact bar 144 carried on tl-ie svjitch closes a holding circuit conliected across the linlit switch LS4, permittin- continued operation Gf the motor after the limit switch LS4 opens. As tiae elevat4ng conveyor is completing its downward movem,-,nt tlie.limit switch LS3 opens, thereb7i breakii-i.- the circuit through the coil 100 an'd opening the switch 99 to sbop the motor M3. A limit switch LS5 connecl.dd betiveen wires 131 and 132 leadirig from the corit-,.tct bar 129, is closed as the elevativ-ig coni7eyor completes its downward movement, and thereby completes the
[4]7 @ly, i ts -. oppp @At @:s contpet.-I?ar .7- 129, @;iAm Aove r d to th , r c ivingrcopWd mp4@, niotqr gQ4 e ,tbe,, jr,,e4i@s-, thrd gh-,the.,mptor,s@vi tch:poil-,-,@4, the v.@qyo@, @a serond,motor :geared to ihe.elevat@,qg timer T, and the relay 90. The circuit...for,tlie Colnveyor,@,a hoisting,motor, opi@rating connee.,p4Dil-@,94rbein.@ thus,.closed,-.th si,;.i ch,,e5,,,Is,closed tions between-the, hoisting motor -and ihe.,elevat@and-.starts the, mQtor,,:M2 and elevating: cQAv@yor - 5 ing. conve or for moving the discharge @eAd -of -the Y ,,T ,be,,cire@iit e;3tabij@$jied thrQi@gh,the. rolay.,$O .As lev ting conveyor up@,vardly as blanks -ar-,e.,dee a noted,r-lifts the@cantact, bar. I l@9 and t e eby livered iherefrom @and for lo-wering- the eqnveyor @shifts the.,motor MI from,:slonv to,,fast spQqd. when a stack of the blanks has been built'up, T,bis.completes the ey,cle,,of -,operatioxis.,initi4ted and automatic control,devices coritrolling the op@.,M.P,aually -.by.. oper@ating tl@e start!Pg -switch '@ 8- 1 10 eration of said motors, said contr.4Dl devices,in@-41id , thereafter -j@hi@tin- the -.selector :switch :to iZIuding, Means for periodically reversin @the 9 ,au Me apparattis will. continue tomatic,,control. hoisV @4g ipotor.and,,thereby lifting a4d lowering oper;ate automatiQally .,,Lintil -stopped @ b .the @y the,,elevatin Ig conveypr, meaiis,for stop Pii@g.,said .,qper-ator. second m t , or, and the elevating ronve r belts @, . Q YO @-During @the automatic pperation it-is possible 15 du ing the lowering of the elevating conveyor, -,.,r. f or the @operat6r. to t effect, any of the -,f ollQv@Ting :4@4d means -for reducing the, s ed of the first . Pe -mer -map - ,a qjust @ts and controlliiig operations @u meritioned motor and r ning the receiving conun A@@y. While the stack of -,blailks: is, be-in. , bvilt, veyor at a reduced speed. during the lowerin pf -9 ,be may "inch" ;the elevating , cqnveyor u P !4e_elei@ating.conveyor. .,w,ar.,dly,by,pressing ,he push-button.switch ia5. 20 2. AppAratus fo an elevatin r convpylr@g , d .This swit,-@h -is interconnected @the sw!tch co i ing.a horizontallydisposed receiv .Mpr. s @-t-06 by a connection -indicated,by btqlcea,line- t45 in all g .cQnveypr including parallel harizont y so,-lh4t,sai.d switches,niove upward,and,downsp.4ped exidless,co veyor belts, puue s at tjae dis,w.ard together. Theav@itches 107,,.a@id tOB@-are charge. end of the receiving conveyor over which interconnectedinli keinai@ger. .WhenthesNvitch, 25 the :@elts are trained, a s4aft oA which 5aid ,1,05 is,,closed, it short circutts the .opQ@@i -sv,7itch @t@03 of the @timer T and -thus permits the hoisting ,-motor :W to run continuously -until the push .:button switch 1,05 is - released. The elevati-iig ,conveyor may -be inched ,,downwai@d by -,-pressing 0 -the "lower" push button,.l R7 while t-he hoisting ,Ulotor,.M-3 is -riu-ining in the direction for hoistin.the conveyor. This oppns the circuit t-h,,,otigh ..the-@motor,,swi't,ch relay 48.,and thereb st ps 'Y .0 pull4@ys Are - mounted,,an elevatin,gconveyor eqipprising.parallel s ced endless conveyor belts, iri . @ 'PA line with said first mentio.ned belts. the. elevating conveyor @eing upwardly and forwardly -in rlined and having its, receiv-ing, plid positioned below the discharge end of the receiving conve r, and guards mounted on, the receiving conveyor f ra e, said r guards being inte Posed between the receivi g conveyor belts and located entirely ben piotorM3 and-at,the@sametime@clpses,the,eir-iLit 35 low the I _plane of.the forwardly traveliXig,,stretc4@,s ,f or the motor - contr I mE@gnet -; 1,90 so , t at the h of the i@ecelym convpygr belts,. said guarcls.ex-s.witch,99,clpses.and,s rts tUe.iAqtor 1,,I3 inthe 'ten @ -@ 9 .tq dir@g -forwardly over the said s aft to.. a @posi h ,reverse. direction,,tliereby lowei@in -onveyor. c t-i directlv over the r ii@g. p4d 0 eceiv ppirti n.pf .By,lsuch up Anddown,.in ing.,Movi@ments -the - Ch. -@he e,levatiag -qQ4vi@yor.,axid the4qe,jdowpWpi@dly .-Iieight,.of the..qlevating qori-vi@yor,,xnay,-.Oe ad- z io between, the conveyor belts. of t4e. elevating_pQ4 ius d at any time to correspond with the, hei ht veyor. ,,Qf,the.,stack :1-6 at the,.time. 3. Appqi@atus for conveylpg aAd To .stop the elevatin.- conveyor, the operator :blanks, joo4@pr@silng a receivi4g,cQnvi@yor,_. n el - . - 9 @ e - p r e s s e s t h e s t o p b u t t o n , 9 2 . T h i s o p e n s @ t l i e e i r - v a @ i n g c o n v e y o r m o u n t e d i n a d v a n c e r e - o f t 4 e -cuit through the relay,94,so.that the motor-switch qq@ivi4g,,convey or in suel-i a manner t]@at t4e,rec.5,is opened@and the motor@M2,stopp ed. The hold- 45 c@eiv!Ag jE@Ad.pf the,elevating conveypr,,Mi@y swing ing circuit for, the "start" switch-93 is also opened -AIZQut a horizonta axis, electric m tors.including -,- @ 1 ., . , , . - -. -o at the contact :bar 120. The pressing @of the a,,two-:4pe@d mqtpr geared to the receiving con"stop" ))utton .92 also opens the cire its -through ve yQr. a,,sqcq;ad u@otqr,gear ed to tlie.plevating @the relays fig and 1.02 which then open.their _q(nyey,or, . a hoistin m tor, opex-Atin _,c nneeg 9 - 9 switches aud thereby ppen the eirquit -through,5( -i n between the ' the motor switch @relay -98 so that -the,,hoistiAg Motor M3 - iS M3 -stopped. The motor m.a be 'Y -stoppe,d independently of the elevatip.a. conveyor motor M2 by shifting,the,,seloctor switGh,9.6 from :Automatic to hazid cqntrol. This.,,ope)qs the,,cir-cuits -throu h:the rele@y coils l@l 0 a@d 1 0'2 wh h Ig ilo -op.orates to stop the rnotor @Y@L3 as just dpscribed. ;-i3y shifting -the selector switch,96 back to auto,matic, the hoisting motor M3 is again started. -To stop aU operations, the operator pushes the .two stop push buttons 88 and 92 and turns the -selector switch 90 to hand control. ,imodifications rnay be resorted to within the ,spirit and scope of our invention. We
