US2493898A - Portable mixing plant - Google Patents

Description

Jan. 10, 1950 H. c. POLLITZ PORTABLE MIXING PLANT 7 Shets-Sheet 1 Filed April 23, 1947 M43 -54, QT-ram ELYJ .Jan. 10, 1950' H. c. POLLlTZ 2,

PORTABLE MIXING PLANT Filed April 23, 1947 '7 Sheets-Sheet 2 WM q-arold. c. wormw wl ea Q J-r-romeyJ Jan. 10, 1950 H. c. POLLITZ 2,493,398

PORTABLE MIXING PLANT Filed April 23, 1947 v 7 Sheets-Sheet 3 m, CH rokal C. poHif J/ZQLE/Z ZM aka/Aha! Jan. 10,1950 H. c. POLLITZ 2,493,898

PORTABLE MIXING PLANT Filed April 23', 1947 7 Sheets-Sheet 4 m Q-larolol c. oll; f

Jan. 10, 1950 H. c. POLLITZ PORTABLE MIXING PLANT 7 SheetsSheet 5 Filed April 23, 1947 l I 1 l l J l I l l l l I I I l |r.lll

NVENTOPWI Jan. 10, 1950 H. c. POLLlTZ PORTABLE MIXING PLANT '7 Sheets-Sheet 6 Filed April 25, 1947 w M .2 WW

J4 ITORN ELY Jan. 10, 1950 H. c. POLLlTZ PORTABLE MIXING PLANT 7 Sheets-Sheet 7 Filed April 23, 1947 rllllllllllll IIIIII v llllllllllllm NVE-NT9- 140mm (3- 01151 34 ghJwJz/ i ATTORNEY-J- Patented Jan. 1 0, 195i PORTABLE MDHNG PLANT Harold C. Pollitz, Cedar Rapids, Iowa, assignor to Iowa Manufacturing Company,

Cedar Rapids, Iowa, a corporation of Iowa Application April 23, 1947, Serial No. 743,309

'7 Claims; 1

The invention relates to apparatus for preparing paving materials and more particularly to apparatus for proportioning and mixing dry aggregates with bituminous or other liquid binders.

The general object of the invention is to provide apparatus of the above general character capable of performing the various operations required in the preparation of bituminous paving materials efiiciently and at minimum cost.

A more specific object is to provide apparatus having means for grading bulk aggregates, preparing accurately proportioned batches of aggregates and liquid binder, thoroughly mixing the aggregates and binder, and delivering the finished product to a truck or carrier, all of which means are incorporated in a unitary structure which can be readily moved from one job to another and which can be changed from operating to transporting condition, and vice versa, very quickly and with a minimum of labor.

Other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment illustrated in the accompanying drawings, in which:

Figure 1 is a side elevational view of material handling apparatus embodying the features of the invention and showing the apparatus set up for use.

Fig. 2 is a side view of the apparatus in transporting condition.

Fig. 3 is a fragmentary longitudinal sectional view of the apparatus.

Fig. 4 is a transverse sectional view of the apparatus taken in a vertical plane substantially on the line 44 of Fig. 1. 1

Fig. 5 is a perspective view showing the elements of the liquid batching means.

Fig. 6 is a fragmentary sectional view showing details of the aggregate batching means.

Fig. '7 is a fragmentary sectional view taken in a vertical plane through the lower end of the skip track and skip.

Fig. 8 is a detailed view of the shock absorber associated with the skip track.

Fig. 9 is a sectional view of the skip track taken in a vertical plane substantially on theline 9--9 of Fig. 2.

Fig. 10 is a section taken on the line Ill-40 of Fig. 3 showing the drum shaft and associated parts.

Fig. 11 is a section through the liquid batching means.

Fig. 12 is a fragmentary elevation of some of the controls.

General arrangement carrying out the invention, I provide in a unitary portable structure, hereinafter referred to as an asphalt mixing plant, all of the material handling and. treating instrumentalities for performing operations required in the preparation ofbituminous paving material. The improved structure includes an aggregate supply and grading unit l5 (Figs. 1-3) for receiving bulk aggregates and grading them according to fineness, an

aggregate batching unit [6 (Figs. 3, 4 and 6) for making up properly proportioned batches of the aggregates, a binder batching unit I! (Figs. 1, 2, and 5) for measuring the liquid binder, and a batch-type mixing unit l8 (Figs. 1-3) for thoroughly mixing the aggregates and the binder. To facilitate operation of the apparatus, the bulk aggregates are delivered to the supply and grading unit l5 by anelevator 19 arranged to pick up the aggregates at ground level as delivered by truck or upon their discharge from a convention- -al drier 20 (Fig. l).

Included in'the supply unit I5 is a multiple compartment bin 2| (Figs. 3 and 6) adapted to receive and separately store the graded aggregates and from which such aggregates may be selectively-discharged into the batching unit Hi. The aggregate batches are then transported from the batching unit I6 to themixing unit 18 by suitable conveying means, herein shown as a batch container or skip 22 traversable from a loading position below the batching unit, as shown in Fig. 1, to a dumping position above the mixer, as

shown in Fig. 3.

.As will be seen by reference to Figs. 1, 3 and 4 of the drawings, the operating elements of the supply and grading unit IS, the bin 2| and theaggregate batching unit 16 are arranged one above the other and theskip 22 is adapted to run beneath the batching unit for gravity flow of the aggregates. The mixin unit I8 is supported in an elevated position in overhanging relation to 1 oft sheet metaL-and; as ,shawnieinsmgsieiis andz, --has.= its/bottom.- Mall ginclinedirtowardwana-apexz'iin which arenlooated-suitable. outlets 101: ithewarious compartments Wain rathe irbin. In a athe. exemplary .a1o1oaratus,.the bin :iSvsPQEtibiOHGd by transverse Walls tomprovidewfour .compartmentsazfil ;fi2,-;53 and 64 disposed longitudinally of the bin.so. 'that thewfinestl-rmaterialais deposited in the1-tbin16l, material of intermediate.- sizesain :bins Glenda-r63, and \the .coarser@materialz-: in loinefi l.

aiMeansiis. rovidediwhereby .oneoi the cgmpartments ,mayvhe withdrawn;v tromasendeeawhen aggre ates of onlmthmetdifgemnt grades-cr is. are required. .zli'orzthise-ipurnose moi themartatitionins avails, in. this msta ,theewall between the compartmentsrii'laatgdafiz; REQYZdQ ha iv tedidefiectomplate ficasa e oivbei s intoaa =position a dcompartment compartment 5. i, r -a,v .g,enera11y. upreh mo ti ttt uss psnin th compartment-r62 ifQ it fii' nt 9ne9 mater a passin th n he sa sm .0-

@Asindica edhexst isreaesshrhinacst partmen is providedw thtaba tpmie e snsiautl tth au ha i whi the-st ed s esate to theplate 56 hygaeanso bracketsflc Each; o the b1 ts-6 6,- ovided With-1a.- ui able aetuator for; closed positions, v

, comprise. JoellcrarH I 1 -.(-Figs. 1 2 and 14) supported i r .v-gv mommsm 421 a l aft 12 carried by-blga ckets -13 towth e bottom end to i essoaq et js id sp a e a link ldqand iaproyjded at i ts other endnw hza hand ip-tie matmalspp tat en- As W11 .b seen b l e eren e: t th meins stn actua in lever, shaft 12 is dispesed horizontally at the side of h his i d ac therw tmljstatio iand the actuatine. .lev r l =i i llipq tiq tha th yma bfi i'lys e l titan da t h le tand neug n 111 ;26-

.As it i s 'e r,ah e..,to. l tqhec 'vth wqu ,Q theassresetesfiu e prq ari gmv ns ma riaLmQans snreyis e. t. A. .h ebynsemnlssme be conveniently al en of each gradenof aggregate as it is deIiVLered to-the aggregate batcher H5. The sampling means, as showmingF-ig. A, comprises a series of =drawe1i l-ike=-trays 16 slidably supported in the framework offlt he apparatus below the bin 2 I-and a-t the; side-thereof opposite the-control station-=25. --T-he---tray-s are adapted to be inserted under. the outlets ofathe-respective bin compartments to catch samples of the-mate-r;

rial discharge therefrom andqmay be readily withdrawn for removalwof the collected-samples.

Ag re ate ba chin T s e ai whi Wi 16 i 'fl lili fid proportiontheaggregates of difierentgsizes withr drawn fromthe bin -2 for each batch; of-paving material to be mixed. To this end the =un-it-emprisesa 'hopper flflsnpportedsbeiowthe bin 21 by weighing nieehan-ism operative -to-sro de a visamo across rm 88 non otat i6 L ual indication pfitheaweight pfsthe ;materia;1;l deposited in the'thopper. Thewhopperwmras herein -shown, is-inzthe form of agenerally-;1:ectangular sheet 'metal box open at .zthestomand hailing. :its

-v -Joottom. .portiont shapedr stosprovide twoalongitudinally extendingitaperingsompantments. eflutlets...at ,sthe lower ends .of the ,eompartmentsare fitted with c, suitablewrclosures,,therein cshown t-as ;enga.ted\meta1 gates .81 (Fig. 4);,pivota1lwsup- -10 ported Qnbrackets 81%...carried-onsthe side Walls-0f zthe :hopper. The carrangementiis tsuch. ..that.;.the gates..-are. adapted to swingibetwleengthe closedsand u p p i i n .sh wn.m peotivelyeinitsolidsand vbroken .li-nes iniFigm 4. When-the gatesareswun to opempositiomthe contents ofihoththonper hom- -.-pa1ztme nts are. .thus directed inwardly to theskip 22,.and:spil1age of;;the;-materi,a1 :isaeftectually 511F08- .wented.

Closure actuating .means. issprovidedawhereby --neously -bythe". attendant.- while standing; on-xthe ;,control.- station platform-2:25. 1' Each; ate 8| -"is formed with-ran,lorutwardlymmjectin ;arms-l aison- .nectedr-bytoeele linksz tfi and 84'zwith-ta track shaft .The .link384 inthi ;:instanrcesis; notmot ably-asecured to .theshafitfl fitso as .to 'rorckztherewithwhen thetshattis actuated thmughathe;sonnectionmr .videdloy axisid armzfit and link 81 to one-endioi' ytrses re o. vacr ti shafhfifi iourna-le d ih rinssr arried; betw th dependin ;-tapered= emnpantments 10f. theihor -As will is seen by-refer nce to His.- 410i thedrawi ss, he links 87; i0. respe tivexeates ;35.V,are connected to opposi e ends of theLarm- V BBZso that the tw to le alinksetsca r -iop nedtorlclosed at the ,same. time. 'Ifhe; sh aft-.

-- onnec ed;byama mr5 and. lev r. 9:2;=p totallys nn r .d y; bit cketafltonia iheaaewe-torsreo tationary fram.e:m9mbe ufl4:ito which; the plattiQ 0 th rame 43.1. vvCaris aexu n p sts ..o

ea h/ pai nar .c n ted at th ir .nuppertends Ja cr sbeams. lnlqand thepos ocat at theccq trol tation side-9f the f am areadditionally con- -.n e by. a, lon itudina ih am 1 0 E ch o ihepost Hwi prpvisie ra bits' lower nd w t a e es qpi s c esls ct on "I 03 te m natins n a ufl ti t JMMQ tel titel 'lareewarea ada e to e onth rq ndi ndi suppo x e ent e b ch uni when t ia pan u is in .topc r t pnjLThGT' Q an .p ts ma e comr -.t.iv 'l c nnecte b bo pr pin 05 in erte through a'lined holes in the respective parts. "Preferably, a series of snchholes are provided in each part and are so spaced that a Wide rangeof ad t e t .-.P. l it d- When the apparatus-is ,to be transported, the legs [03 are retractedto'the positionv Shownin Fig, 2 and are securedin such position bythe =--pi ns [05. The auxiliary frame is then supported by the --crossbeams IU'I resting -on heams 1'06 (Fig. 4) extending longitudinally of and forming a part of the plant framework.

The weighing mechanism by which thehopper 80 is supported on the auxiliary frame may be of more or less conventional character. As herein shown, thehopper is suspended from torsion bars IIII (Figs. 4 and 6), which in turn are supported from the crossbeams IIII by depending adjustable links III. Two of the bars III] are provided, one adjacent each end of the hopper, and each bar is provided with a pair of rigid, laterally projecting arms H2 connected by depending links II3 with angle bars Il l secured to the ends of the hopper. The arrangement is such that the weight of the hopper and its load tends to rock the torsion bars about their longitudinal axes. To reduce frictional resistance, the movable joints between the parts are fulcrumed on the usual knife-edge bearings.

Projecting inwardly from the respective torsion bars I ID are a pair of long arms I I5 (Fig. 6) provided at their adjacent ends with knife-edge bearing elements adapted to engage a common fulcrum member IIB which is connected by an adjustable link I I! with one end of a scale beam H8. The scale beam is suspended intermediate its end from the beam I02 of the auxiliary frame by a suspension member IIS and its other end is connected by a link I20 with a weight indicator I2I preferably of the dial type.

To facilitate the batching operations, the indicator I2I is located at the control station adjacent one end of theplatform 26, where it is readily visible to the attendant while manipulating the aggregate releasing levers 'II. As shown in Fig. 4, the indicator I2I is carried by a bracket I22 pivotally supported on one of the posts I00 of the auxiliary frame. By reason of its pivotal support, the indicator and bracket may be swung into a position closely adjacent the side of the main frame of the plant, as shown in broken lines in Fig. 2, when the plant is to be moved. It will be understood, of course, that under such conditions the indicator is disconnected from the scale beam, the connecting means being formed to facilitate such disconnection. The beam may then be shifted to an out-of-the-way position and made fast to the framework in any preferred manner.

Batch conveyor The aggregate batches upon discharge from the weighinghopper 80 are received in theskip 22 and conveyed to the mixing unit I8 under control of the attendant. Theskip 22 is made of sheet metal and has upright side walls I30 and an upright rear wall I3I. It is closed at the bottom by a wall I32 which is flat adjacent the rear end of the skip and inclined upwardly at its forward end so as to prevent spillage of material during movements of the skip while permitting the material to be discharged when the skip is tipped up to the position shown in Fig. 3.

Support for the skip is provided by flanged wheels I33, two being provided'at each side thereof. The wheels run on an inclined track formed by spaced parallel rails I34 (Figs. 3 and 4) which extend from a point below the forward end of thehopper 80 to a point directly above the mixing unit I8. In the exemplary apparatus, the rails I34 are carried by inwardly facing channel members I35 suitably supported on the framework of the plant and having flanges I36 overlying the wheels I33 so as to prevent them from leavingthe rails. Adjacent the upper end of the track the guide flanges I36 are turned upwardly.

as at I31, to permittheskip to tilt to the dumping position in which it is shown in Fig. 3. Fixed stops I38 secured to the channels I35 for engagement by the front pair of wheels I33 limit the upward :movement of the skip to the position shown.

In order to minimize the over-all height of the plant, therails I34 and channels I35 are constructed in sections, one of which extends beneath the hopper 8D. This section is pivotally supported by brackets I35 to swing between operating and transporting positions shown respectively in solid and broken lines in Fig. 3. When the pivoted track section is in its lower position, suflicient clearance is provided for theskip 22 to enter below the hopper (as shown in Fig. 1).

In setting up the plant for operation, a shallow pit MI] is dug below the pivoted track section to accommodate the skip. When the plant is to be moved, the skip is withdrawn to the intermediate portion of the track where it may be blocked in place by a cross member I4I of wood or other suitable material inserted between the rear wall of the'skip and a suitable portion of the framework. The pivoted track section may then 'be swung up to provide ample road clearance, as

shown in Fig. 2. To hold the track section in the raised position, the channels I35 are provided at their lower end with forwardly and laterally projecting lugs I43 (Figs. 7 and 8) adapted to abut one of the cross members of the frame 3| and to be temporarily secured thereto as by bolts I44.

For traversing theskip 22 from the loading position to the dumping position, hoisting means including a pair of cable winding drums I55 (Figs. 3 and 10) is provided. The drums are carried by a shaft I5I journaled in brackets I52 carried by uprights I53 forming a part of the framework of the apparatus. To provide the necessary strength and rigidity the uprights I53 are reenforced by diagonal braces I54. A cable I55 has its opposite ends anchored to the respective drums and the bight is carried over a pair of sheaves I56 mounted on a head frame at the upper end of the skip track and then looped around the skip'22, as shown in Figs. 4 and 7.

The sheave supporting head frame as herein shown comprises upright side members I51 pivotally supported on theframework above the binder batcher I! and forwardly extending bracing members I58 detachably connected to the uprights I53. The arrangement is such that the sheaves I55 are firmly supported substantially in alinement with the inclined portion of the skip track so as to maintain the cable I55 in a straight run throughout the movements of the skip. By detaching the bracing members I58 from the framework the head frame may be folded in the retracted position shown in Fig. 2, thus reducing the over-all height of the plant to a minimum and adapting it for transportation over public highways.

To equalize the strains on the two runs of the cable I55 the cable runs are led over rounded guides I68 (Figs. 3 and '7) welded to the sides of the skip and thence over grooved rollers I6I (Figs. 4 and 7) rotatably supported on the back wall I3I of the skip. Intermediate the rollers IIiI the cable is anchored to the skip by clamping devices I62.

In the exemplary mixing plant the drum shaft I5I is adapted to be driven by aclutch I65 having its driven member I65 rotatably mounted on the shaft. The member I65 is driven in this instance by a chain I66 from the rear drive. shaft 29. The .clutch is preferably arranged for hydraulic actuation by fluid supplied from a master cylinder I68 (Fig. 4) having a piston actuated by a hand lever I69. Fluid is delivered to the clutch actuator through a passage extending axially of the shaft I5! and connected by a fitting I66'-with a conduit 51' communicating with the master cylinder. As shown in Fig. 4, the cylinder I68 is supported on the framework 3I at one side of the apparatus adjacent the control station and the actuating'lever IE9 is mounted for convenient access by the attendant while-standing on the control platform. 26. i

Theskip 22 is adapted to returnto loading position by gravity upon release of the driving clutch and the shaft I5I is therefore desirably provided with a suitable brake I69" (Fig. 10) for controlling or interrupting such descent: The brake means may be of the'usual automotive type operated by fluid under pressure supplied by way of a conduit I10 from a master cylinder .I1il mounted on the underside of theplatform 26, as shown in Fig. 13. The piston of the master cylinder is actuated-by a foot pedal, I1I projecting through theplatform 26 so that it may b conveniently reached by the attendant. I v

Means is provided for stopping theskip 22 with a minimum of shock upon its descent to the loading position. ,As shown in 'Figs. 7 and 8, this means comprisesa shock absorber I of the usual cylinder and piston type supported on the frame 3! of thechassisadjacent the lower end of the skip track. The shock absorber has an actuating member I16 positioned forengagement by the rear wall I3 I' of the skip as the latter moves into theloading position.- I 1 Support for the shock absorber I15 is provided by a channel, member I11 adapted to be bolted or otherwise removably secured to the frame 3|.

In the exemplary embodiment, the cylinder poris connectedby a-pin :I M-with the flanged portion of the shock absorber. The other end of -.the

'member I16 extends rearwardly through a slot in the-channelmember I11 and isjprovided with a contact element or roller I85 for engagement by the skip.

When theskip 22. is-away from the-loading position, the shock. absorber plunger is retracted into its cylinder and the actuating member I16 is held in the position shown in Fig."'7 by a pair of springs I86 connectedbetween the plate I18 and the forward end of the actuating member. As the skip approaches the'loading position it engages theroller I androcks the actuating member to the position shown inbroken lines of the drawing. In this movement the plunger of the shock absorber is shifted longitudinally of the cylinder, whereby the skipwis-gradually decelerated. A bumper'I61 of rubber orr'other resilient. material carried by thegangle bar I 119.

Binder batching unit The binder batchin unit I1, as shown in 'Figs. 5 and 11, comprises a general oval tank orbucket 200 open at the top and having a frustoconical bottom with an outlet closed by a gate or valve MI. Thebucket 200 is preferably constructed with double walls so that steam may be circulated thereabout to keep the contents hot and in a fluid condition. Steam may be supplied to the bucket by way of a flexible conduit 20I connected with a suitable boiler (not shown). When oil or non-asphaltic binders are used, the steam connection may be closed. A spreader tank 202 (Figs. 1 and 2) located below the outlet 2M receives the discharged material and distributes it evenly to the mixing unit I8.

To enable the contents of the batcher to be measured, the bucket 260 is supported from an upright frame 2| 2 by weighing mechanism 205 (Fig. 5) connected with a suitabledial type indicator 206 mounted on the framework at thecontrol station 25. As herein shown (Fig. 11), thetank 200 is supported by a hook 261 anchored to a cross-bar 208 extending across the top of the tank and engaging a clevis 209 carried at one end of a scale lever 2I0. The lever is supported intermediate its ends by a hook and clevis connection 2 from the frame 2i2. The other end of the lever 210 is connected by a link 2I3 with one end of a lever 2I4 fulcrumed at its other end on a beam 2I5 supported on and projecting rearwardly from the chassis frame 3|. The intermediate portion of the lever 2M is operatively connected by a tubular torsion bar 2I6 with a similar lever 2 I4 suspended at one end from the beam operatively connected with the indicating mechanism thereof by a link 2I8. The arrangement is such that the weight of the material deposited in thebucket 20!) is visually indicated to the attendant standing on theplatform 26 at the control station.

Liquid binder is-delivered to thebucket 206 by a pump 220 (Fig. 3) of any suitable character through a flexible conduit, such as a jointed pipe 22I, which is preferably steam-jacketed to permit the handling of asphaltic or other material requiring heating; In the exemplary structure thepump 220 is mounted adjacent the rear end of the chassis frame 3I and is arranged to be driven from the countershaft 4| by thechain 222. The countershaft may be driven bya chain or other suitable connection from the rear drive shaft 29. Preferably, a suitable clutch operablebya hand lever 223 is interposed in the pump drive so that it may be started or stopped at will. In the exemplary apparatus apipe 224 with a suitable coupling 224' is provided for connecting the intake side of the pump to a tank car or the like from which, the

supply of liquid binding material is obtained.

: i For controlling the delivery of binding material to thebatching bucket 26!] the supply pipe 22I is provide'dat its discharge end with a valve 225 adapted to be opened or closed by remote control from thecontrol station 25. For this purpose the valve may be provided with a convenanauxiliary shaft 231.

11 The gate or-valve 2-111! for the bucket outlefi may also be equipped witha 'hydraulic actuator- 22 8 for remote operation under control of a master cylinder,mechanism 229 at the. control station.

Itwillbe understood; of course, thatthepump-HD is continuously operating, so'asnotto: be frozen by'vi'scous bituminous liquids, and the valve delivering the binding material to the batching bucket is of a three way type, allowing continuous circulation oithe binding material; i': e.-, from storage tank to pump, then to'valve; and from valve either into batching-bucket or back to storage tank; the latter also preferably by way of steam jacketed piping;

4 'Miazing unit; The mixing'unit I 8 in which thedry aggregates and liquid binder are intermixed and blended together is preferably of the pug mill typehaving a mixingmember 230" rotatable about a vertical axis within a generallycylindrical hopper 230 iFigs'. 1-3). The mixing member 2% ifs driven in thi's inst'ance from the rear drive shaft 2 5 Inthe exemplary mixing plant the hopper 2%!) is mounted onan extension of the chassis frame '3 formed by the beam 21-5 and a similanbeam arranged parallel thereto at the other side as the machine. The beams are anchored at their f'or- Ward. ends to the uprights- 4? and are ap eared intermediatelyon suitablyreenforc'ed pcsts U53 extending upwardly'f-rom the chassis franie The ends of thebeams 215 thusproject substantially beyond and overhang the rear end of thechassis so that a truck or other carrier may be-driverrum der it and the mixed material delivered directly 'thereto by gravity. A shallow trench. or runway 233- may be excavated below the mining hopper "when the apparatus is set up fbr operation to provide the necessa-ry'clearancefor relatively high trucks; j

For discharging the mixed-material, thehopper 230-is' provided'with a bottom opening outlet closed byaslideor gate 235; (Fig; 3") The slidisaifranged for power operation by a'n actuatorflafi, preferably of the cylinder and piston supported on the framework forwardiy'of the hopper.

The actuator may be operated by steamifromjthe same source usedior HEEfiiiQRUIpOSBS; or when steam is not available, compressed air from any- 7 suitable source may be employed. It will lie-jappreciat'ed that a compressorsuitable ionthis'purpose may be provided on the machine framea-rrd drivenfrom the prime mover 23', if" desiredi "A manually operable valve '231 is provided? at the?- controlstation for controlling thesupply of steam or air to the actuator 236: f

Rswmoj operations- Assuming that the min-ingplantis set-' as:

' shown in Fig. 1, it is placed in operation by starting the engine 2 3 which dTiVBSthE" drive s'hafts fl,

29'; 4 1" and? 59-. The intakepipe Hdbfthe pump 220 is connect'ed to a tank car or other container nom-aspha'lti'o hinders, the steanr connecting-is simply'omit'ted and the: gate a'ctuator'm is: cannected toa compressed air-"line;

Dry aggregates dumpefi intoa the pit are? i ill ' f holding the binding material andthe pump is-cs startectby= actuation of'the olut'ch'lever 2 131 'When using a binder of the asphaltic type, the steam line from a suitable boiler connected for supplying steam from the jackete'd pipe-2211 and the batching tank 200- wherebytheebinderiis kept hot:

- and i'nzflui'd condition. 'Foruse-witlir oil-'orother oarried bytheelevatoril ofthessupply ana ram ihg unit to the shakefscreen'MI-J The elevator is d'rivem continuously from the firont drive 28 through theimmediate drive shaft 59 and the shaker 'screenis agitated' by the eccentric 40, which: is driven from the rear drive shaft 29 thrcuglr the countershaf-t w'. The material delivered -to the screen W' i's classifiedaccording to fineness" anddistributed to the various compartments of thelfiih 2-1 In practice, the compartmentsare usuaills maintained substantially full was to provide a=reserve supply of aggregates.

To form a batch of aggregates; the attendant'by manipulating: the various-handlevers Tl openswhe bin compartments i'rr succession until the desired quantity of eaclr grade of aggregate is dizli vered totheahopper 80, as indicated 'bythe-scale indicator 121 Sampl'esmay be taken clutchfbr the drum shaft I?! As-the shaft rotaitesg the cabl'e Isms vvouncfon the drum [-50, thereby drawing the skip upwardly until the front wheels las engagethe fixedistops I38. Further winding of the -cabie" tilts the skip tothe positibn sh'ewrr in E-ig. 3, thereby dumping its contents into the hopper" 2311 of the mixing unit. The drumshaft' cliitchis disengaged when the skip moves into the dumping position'and' the themreturns by -graa ity'te theloading positibna' Return speed of the is: regulated by thedrum shai t brake which is controlled by the attendant.through-the'mediunr of the foot pedal n l and the associated master-- cyiinder mechanism m1; 7 V

'Durihgtheiorming ortheageregate batch, the

attendantmayal'sm prepare a batch of binding 'material for mixing therewvithr This is. done actuating then-raster cylinder"mechanism 221 to open theyaiye- Z25 controlling 'thedis'charge of bindingmaterial from the pipe .22 1 to-the batchm bucket :200. Theamountof material deliveredito the tank is determined by: observation of the scale oi? the indicator 2 08; When suflicient material; has: delivered, the valve 225 is closed byactuatibn oix'the master cylinder mechanism.

After the aggreg-ate batch has been dumped into the mixing unit as above explained"; the outlet valve for the batch-ing bucket 20b is opened by actuation of themaster cylinder mechanism 229, thus-permitting the; binder to drain into the spreader-tank- 202 "and from there into the mixer hopper" The aggregates "and binder are then mixed and blended in well -known manner. Ordinarily sucl'r mixing-. is. alibwed to proceed for arpnedet'ermined time andithe mixed; materialis thenrdischarged 'by opening thegate 235; Such opening is controlled? by the attendant at; the control; station by the; setting of the valve 231 c to: admiti'steaimon compressed ail: the actuator y-reason or theadvantageous location of the uniting: unit with respect to the chassis upon which; the. apparatus isrmountedg. a trucker other 13 suitable carrier may be run below the unit to receive directly the material discharged therefrom. Unnecessary handling of the mixed material is thus avoided and the time required for the transfer of the material is reduced to a minimum.

To place the mixing plant in condition for travel, theelevator 19 and the head frame l! of the skip are folded into out-of-the-way positions, as shown in Fig. 2. The skip 22'is drawn up to an intermediate position and blocked in place by means of the crosspiece l4]. After removal of the shock absorber supporting channel l1! and release of thejacks 36, the hinged section of the skip track is raised to its upper position and secured to the frame 3| by the bolts I44 to afford suflicient road clearance. v

As explained heretofore, during the operation of the apparatus the weighing hopper Bil is supported on the ground by the auxiliary frame, including the posts I00. To condition the apparatus for transportation, the leg sections [03 of the posts are released by withdrawal of the pins I05 and when raised to traveling position are locked in place by reinsertion of the pins. The scale beam H8 is swung to a retracted position or removed and otherelements of the weighing mechanism are suitably secured to the frame to avoid damage while the apparatus is in motion. The indicator l2l is swung to a traveling position closely adjacent the side of the frame.

To reduce the lateral dimensions of the apparatus, thecontrol platform 26 is folded'upwardly along the side of the chassis frame. Thus both the vertical and horizontal dimensions of the apparatus are reduced to a minimum, well within the limits prescribed by public highway regulations. It is then only necessary to attach thedrawbar 35 to a truck or tractor by which the apparatus may be towed; The provision of pneumatic tires on the supportingtrucks permits the apparatus to be towed over public highways and at relatively high speeds.

It will be apparent from the foregoing that the invention provides a portable mixing plant of a novel and advantageous character capable of performing the various operations required in the preparation of bituminous paving material. Bulk aggregates are effectively graded and stored, thus eliminating the expense and difficulty of handling I All materials entering into to operating condition; or vice versa, very quickly and with a minimum of labor.

I claim as my invention:

1. In a portable mixing plant of the type described having means for mixing aggregates with liquid binding material, the combination of means for separating bulk aggregates according to fineness, a conveyor for delivering the aggregates to said separating means, a bin having a plurality of compartments for receiving and storing the separated aggregates, means supporting said bin substantially on a level with the mixing means, a weighing hopper disposed below said bin, said bin having gates operable to release aggregates from said compartments selectively to prepare a batch of aggregates in said hopper, means for transferring the batch of aggregates from said hopper to said mixer including a skip movable from a loading position below said hopper to a discharge position above the mixer, power driven means for moving said skip, a weighing bucket for liquid binding material adapted to discharge the material into the mixer, closure means for controlling the discharge of binding material from said bucket, other closure means for controlling the discharge of mixed material from the mixer, a control station including an operators platform located adjacent said 'bin providing convenient access to said gates for manual operation of the same, and means at said station for controlling the operation of both of said closure means, said platform being movable to a retracted position without disturbing said controlling means to condition the plant for traveling, all of said foregoing elements being assembled in a unitary structure supported on a wheeled chassis.

2. In a portable mixing plant of the type described having means for mixing aggregates with liquid binding material and for delivering the mixture directly to a truck or the like by gravity flow, the combination of a screening device for separating bulk aggregates according to fineness, a conveyor for delivering the aggregates to said device, a bin disposed below said device having a plurality of compartments for receiving and storing the separated aggregates, a weighing hopper disposed below said bin, and at a level substantially below that of the mixing means, said bin having gates operable to release aggregates for gravity flow from said compartments into said hopper, an inclined track extending beneath said hopper and to a point above the mixing means, a skip supported and. guided on said track for movement from a loading position below said hopper to a discharge position above the mixing means, power driven means for moving said skip on said track, a control station located adjacent said bin providing convenient access to said gates for manual operation of the same, meansat said station for controlling the operation of said power driven means, and other means at said station for controlling the discharge of material from said mixing means, all of said foregoing elements being assembled in a unitary structure supported on a wheeled chassis.

3. Ina portable mixing plant of the type described having means for mixing aggregates with liquid binding material, the combination of a screening device for separating bulk aggregates according to fineness, a conveyor for delivering the aggregates to said device, a bin disposed below said device having a plurality of compartments at a level substantially below that of the mixing means, said bin having gates operable to release aggregates for gravity flow from said compartments into said hopper, an inclined track extending beneath said hopper and to a point above the mixing means, a skip supported and guided on said track for movement from a loading position below said hopper to a discharge position above the mixing means, all of the foregoing elements being assembled in a unitary structure and supported on a wheeled vehicle, the section of said track beneath said hopper being pivotally supported to swing to a retracted position when the apparatus is to be transported.

4.- In a mixing plant of the type described having assembled in a unitary portable structure means for mixing aggregates with liquid binding glean-gee:

15 mateniali. a sereeningdevice fo p rat ng? ulk: a negatesa cordin s to: fineness a c v y r for delivering.- the; a r ates; o; a d. ev c a bin dispossdebelow said; devi e having ap fi f Compartments-for receiving andstoring-the separated aggregates,- a weighing hopper disposed beiow-sa-idbin at,alevelbelow that of the mixing meanasaid binhaving gates operableto release aggregates; for gravityflow from said compartmerits-into saidhopper, an inclined track extending; beneath; said, hopperand to a point above them-ixin mea-naa; skip supported and guided on said-track. for movement from a loading position below. said hopper; to a discharge position above the mixing; means, a hydraulic shock absorber supported adjacent, the lower end of said track angle-bumper connected, withsaid shock absorber and, positioned; for engagement by said skip as it approaches the lower end of the track, said bumper and said shock absorber being supported for. convenient.removalrto condition the plant for tnanel, V

5. In; a portable mixing plant of the type described having means for mixing aggregates with liqnidbindingmaterial su ported inelevated positionforg-ravity discharge into a truck or the like, the combina ion; 0 2 a s re ning d vi for separa ing bulk aggregates according to fineness, conveyor for deliverin the a re tes to id evice; a; bin disposed;substan ially- 0n h me leyieleaszsaidlmixing means: and below said device having, a plurality. of compartments for receiving and-storing thesepara ed ag r a afw i hin hopper disposedahelow said bin, said bin having gates; operable tonrelnasfi aggregates. for gravity flow. fnomsaidcompantments into said hopper, an inclined track. extending beneath said hopper and tea pointabcve-themixing means, a ski v supported and guided on said track for movement from tloading position below said hopper tova discharge position above the mixing means, a

head fname extending above, the upper e of said track sheaves. journaled on said. head frame, and means, including cables running over said sheaves; for pulling. saidrskip up saidv track, allv of the foregoing elements being assembled in a unitary. stpuctune and supported on a. wheeled chassis, said; head framebeing retractable to reduce overhead clearance requirementswhen the mixin plan -is being .transp charge, an aggregate batching unitsupported at he; oth r: Q'JQYOL saidin xn e n dina a multip e cemn nnenta ii ggteJoint an. e vat efi r arryngea gnegates osa d maid-elevator exte in bBIOWrthQJQYQI, of, the Suriacerupon Which said whee ed:- rucksarersupnerted and b ng t a a l substanti lly abe e netrncks when the plant is to? be transported, a weighing; hopper disposed el w he vel.v of. said m xing. uni i ct y be! neath said: bin ore eive the a rega es dishar d: t erei-in n. m ans. nclud n a; s p f r transfern ngi gre ates. fr m: s id weig ng hopper to: the mixing; unit, a track. for. said skip xt ndingmelqn he hopper. po t on of said trac eingrretn eta lea lp nvidey oad: clearance when h enl nt sra eling cen ral tation! fo controlling the operation, 011' the plant, and a hon zonta ln d seased plat-inn n n. he pe r atsaid staticnsl.s id-;n atic 1n:. e ng swin ble to aver icalp sitienl adigeentsaid cpp to reduce he qveraili. wid h? 0-. th plan w n traveling: l

A: prin able asphalt:mixin znlanticomprisln n omb n iiqnia nassis-inclu ing: an elon a d frame-ha n ;wheele meksatnnn sit lends for hi hway itanhmeans en enenat n k a regates amending ta said s para in meansb ingm nnted cnsaide ra einan e evat d P n adja entnemaoiesaidchass s, a conveyor, disposed a s id endv iechassis for receiving bullsyagg gegates; at, substantially groundzie li anfilfl ii de iverin th a grega to sai epan iing;me ;n; a in-esnpnqrte on i ram helnwsaicisen ating means andw avin a pl rality oi snninantxnnt inn ece ng a d s rins enan tedy ggn ates; eign g hqnpe sposed belcwv sa d in toreceive the a re e dischar ed nerein mr a m n n u t suppo inv e evatedpcs tiqn. adjacenthe ether e d o said f ameion clisnnar edix-g t y nto a vehicle, a skin QIF nansienn ngtn gn gete bat h from said honnen t aid mixing unit and n nc e track for said skip extending .from a pointbelow said hopper; toa. pointyabove said mixing unit, the. nwere portion otsa si t a k, bein etractable to pn yide road. clearance. when the an is traveling,

c1. BOLLITZ.

CITED ATE T N S

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