US2441532A

US2441532A - Machine or apparatus for surfacing roads

Info

Publication number: US2441532A
Application number: US579350A
Authority: US
Inventors: Arnold S Millikin; John H Apel
Original assignee: Jaeger Machine Co
Current assignee: Jaeger Machine Co
Priority date: 1945-02-23
Filing date: 1945-02-23
Publication date: 1948-05-11
Anticipated expiration: 1965-05-11

Description

y ,1948. A. s. MlLLlKlN EI'AL MACHINE OR APPARATUS FOR SURFACING ROADS Filed Feb. 23, 1945 3 Sheets-Sheet l INVENTORS Arno/d 5. M/Y/l/(lfl. John h. Apel.

M MM

A TTORNE Y5 May 11, 1948. A. s. MILLIKIN ET AL 2,441,532

MACHINE OR APPARATUS FOR SURFACING ROADS A TTORNEYS v 5 Sheets-Sheet 3 INVENTORS, Arno/d .5 M/Y/ik/n.

I BY Jo/7n Ape/ W n [M 3 A TTORNEYS May 11,1948. A. s. MlLLlKlN ETAL MACHINE OR APPARATUS FOR SURFAdING ROADS Filed Feb. 25, 1945 Patented May 11, 1948 when "UNITED STATES PATENT OFFICE MACHINE on APPARATUS For: sUaFAciNG ROADS Arnold S. Millikin'and JohnH; Apel; Columbus, Ohio, assignors to The Jaeger Machine Company, Columbus, Ohio, a corporation of Ohio Application'F ebruary 23, 1945; Serial No; 579,350

12 Claims. 1

Our presentinvention-relates to a machine or apparatus for surfacing roads. It has to do particularly with an apparatus for producing a smooth-and 'level surface on a layer of material Which'is .being ap'plied to-an old' road surface or to a'rough 'graded surface. Moreparticularly it has to do with means; preferably electrically actuated or operable control means, for raising and/or lowering the leveling and finishing unit of the machine; -at predetermined times and in accordance withroad surface conditions.

The improved 'machine or apparatus of our inventi'on'i is particularly useful in connection with theslaying"and/or'repairing "of road and other surfacesiformed from various materials, such as bituminous mixeseon'cr'ete; et'cetera; The machineor apparatus as disclosed" herein and' with which the'electricalcontrolmeans embodying our present invention'isfi associated generally speakingrsimilar in 'somerespects to that embodied? in United StatesuLetters Patent No. 2,295,519',-='to MillikiniandPickardyissued September 8,1942. A

One" of the objects of the present invention is toprovide electrical or'siin'ilar 'control 'means for a machine or apparatus-adapted particularly for surfacing-roads andwhich is of such a nature that ram irregularities in thesur'face being covered by the-material will-be averaged "out in the finished surface 'so that sai'drfi'nished surface will be-free 'of any;; and :all' sharp: irregularities or bumps? due *to the automatic actionof s'aid con trol:means':

Anotherfobject of:=our invntion is to provide improved" controlmeans,=- such as electrically' actuated control means, for a machine'or' appa= ratus for surfacing roads; or-thelike; which latter-= is ot-such arnature that-sit maybe usedlin' i'esurfac-ingiold.road-surfacesto producea new surface having-the'same'general grade as-the old an entirelyldifferent grade than the old surface beingcovered A Another object of our invention is to provide improved, preferably iele'ctricalcontroli means, for a machine cit-apparatus forsurfacing. a road," whichm ac'hin'e 'or"apparatusincludes a leveling and'finishing-"unit'"adapted to smooth and level the'surfafce of'the material being appliedythe machine or'apparat-us' being of such anature' that" '40 surface'-with :thee sharp-irregularities thereof eliminated; or to-produce-a new surface having the finishing unitresting upon the layer of mat'erial ivi'll'hot support any substantial weight of J the *mach'ir'fe in order I to preventundue com-'- pacti'on A ofthe'* layerof materiail so '-asnot to retard the curing or"setting of the material;

animproved 'machine or apparatus matic'allyupon"the'engagement of the material receivihg' an'dfeedi'ng unit of the machine or' apparatus with raised portions" or depressions occurring in the old road surface;

Afurther obj ect' of' our invention isto provide a" machine' or apparatus "of" the "foregoing character" with"self-containdelectri'cal power means and'ai normally 'open electric switch mechanism which is c-apable' of beirigrende'red operative "to raise and lowertheleveling and finis ng unit of the machinewhen the material-receivin and feeding withuneven portions of the old road surfacei-to thus quickly, accurately and automati'cally=re'adjust the leveling and en- 1 ishing unit with relation toth'e remainder of the machine or apparatus to permit the laying of the" 'witha predetermined or unit comes "into contact material "accordance re=ca1cu1ated grade. Generally'speakingi' whichthe control means of is-associated; consists, preferably; of two main units. Theseunit's are a'material receiving and feeding unit" and-a material leveling andfinishing unit? The"material receiving and feeding unit A may be of any suitable type such, for example; as" that "disclosed by the" above-mentioned Millikin and Pickard atent, and'is carried by' suitable traction means which operate upon'tliesub-grade or" the 'old road surface being covered. The level"- ing and" finishing unit is associated with I the and arranged material receiving and feeding unit intandem 'relationship with respect thereto in such "a manner -that "relative verticalmovement 1 between thesetwouni'ts is permitted as the ma chine of apparatus moves over the surface of the roadway, or the like. The leveling and finishing unit embodies, as shOWhI-a transversely extending dead screedarid a *high speed oscillating cutoff bar or compactorwhich is associated withthe screed; the screed and bar being disposed or located behind the material receiving and feeding 1 unit? Following-the leveling and finishing unit andconnected thereto is a so-called control m'em' her or: [a pa ir of transversely space-d control momand as shown merely by" way ofexa'mple', the machine or apparatuswith our present invention bers, for example, leveling pans, which are adapted engage and ride over the surface of the material which has been laid for maintaining the proper surface elevation of the newly laid material. In normal operation over a given grade or surface which has been newly laid, the leveling and finishing unit and the control means or members (pans) remain substantially in parallelism. The machine or apparatus also includes means which is preferably electrically actuated automatically due to the uneven contour of the old road surface which the forward end of the machine travels over.

If the old road being newly surfaced has an adjacent curb or header which can be used as a grade line, laterally projecting levers carrying similar but smaller leveling pans, or the like may be employed to ride over the surface of said curb I and thus serve to maintain the proper grade level.

It will be apparent that since the material receiving and feeding unit operates on the rough sub-grade or old road surface, it will be moved vertically because of such irregularities. To reduce such movement, this unit is preferably carried by relatively long caterpillar traction elements. These elements and associated runners substantially prevent any small or minute irregularities from affecting this unit. The larger and sharp irregularities in the surface being covered will, however, produce some vertical movement of the material receiving and feeding unit. This Vertical movement of the unit has a tendency to move the leveling and finishing unit which is pulled along behind the material receiving and feeding unit, vertically, and to thereby cause any sharp irregularities of the surface being covered to be reflected in the finished surface. Therefore, the control means above referred to is provided which, together with the leveling and finishing unit, automatically control the level 'of the lastnamed unit so as to average out any sudden rises and depressions in the surface being covered as reflected in the finished surface. That is to say, if the surface being covered has sharp rises and depressions, these will be reflected in the finished surface but will be in the nature of gradual rises and depressions which will be practically unnoticeable. Consequently, the surface produced by the apparatus will be an extremely smooth and even riding surface due to the automatic action of the electrical control means.

The foregoing and other objects and advantages of our invention will be apparent from the following description and appended claims when considered in connection with the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In said drawings:

Fig. 1 is a fragmentary rear perspective view of a machine or apparatus embodying the present invention.

Fig. la is an enlarged fragmentary detail perspective view of one of the leveling pans or members of Fig. 1 and its associated parts.

Fig. 2 is a right side elevational view of the machine or apparatus of Fig. 1.

Fig. 3 is a rear end elevational view of the finishing unit and controls of the machine or apparatus of the preceding figures.

Fig. 4 is a top plan view of the structure shown in Fig. 3.

Fig. 5 is an enlarged detail elevational view, partly in section and partly broken away, of one of the electric switch units or assemblies associated with the control means of the present invention.

Fig. 6 is a vertical sectional view taken substantially along the line 6-6 of Fig. 5, looking in the direction of the arrows; and

Fig. '7 is a diagrammatic view of an electrical circuit for operating the switch mechanism of Figs. 5 and 6.

Before explaining in detail the present invention it is to be understood that the invention is .not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practicedor carried out in various ways. It is to be understood also that the phraseology or terminology employed herein is for the purpose of descrlption and not of limitation.

Referring now to the drawings and particularly to Figs. 1 to 4, inclusive, thereof, one type of machine or apparatus for surfacing roads to which our present invention is applicable, is shown as a whole at IU. As shown, it comprises a material receiving and feeding unit, shown as a whole at I l and a following leveling and finishing unit, shown as a whole at l2. The leveling and finishing unit is drawn along behind the material receiving and feeding unit.

The machine or apparatus I0 is carried by a pair of relatively long endless traction units I3, one such being shown. These traction units or members will pass over small irregularities of the sub-grade or old road. surface without causing any appreciable vertical movement of the unit I l.

The leveling and finishing unit I2 comprises a screed M which may be a dead screed and a rapidly oscillatable cut-01f bar or compactor IS. The leveling and finishing unit is mounted upon framework including transverse frame members i 6 and upright frame members IT, This structure may be substantially the same as that disclosed in the co-pending application of Obert G.

Mandt and Arnold S. Millikin, Serial No. 565,306.

The machine In is provided with longitudinal side frame members l8 which, as shown, are fastened at l9 to the upright frame members l'l. Each frame member l8 carries a runner 20, see particularly Fig. 1, which is pivotally mounted at 8 for oscillating or rocking movement relative to the frame member l8. The forward end of the runner 20 is also connected to the frame member 3 by a pin and slot connection, shown at 9. Thus, when the traction members [3 are driven, the material leveling and finishing unit [2 will be drawn along behind the material receiving and feeding unit H.

The frame structure above the unit [2 also comprises a pair of transverse frame members 2| which carry an electric motor 22 drivingly connected to a drive shaft 23 which serves to oscillate the cut-off bar or compactor l5 in substantially the same manner as disclosed in the aforesaid co-pending application. Moreover, the upright frame members I! carry means for supporting and raising and lowering the leveling and finishing unit l2, such means being generally similar to that disclosed in the Mandt and Millikin application, insofar as the supporting means for the unit I2 is concerned. As shown, such supporting means comprises a vertically extending screw threaded shaft 24, one such being located between each pair of the upright frame members ll. The lower ends of the rods 24 carry hanger blocks 25, see particularly Figs. 1, 2 and 3. The

45a of a transversely sidewise-projecting rod or shaft 46. This rod is preferably carried by a rearwardly projecting rod or shaft 41 whose inner end is carried by a bracket or coupling member 48 which is adjustably and removably mounted upon the outer end portion of the shaft or rod 31a lo cated at that side of the machine. The bracket 48 is held in fixed relation to the shaft by means of suitable screws or a pair of bolt and lock nut assemblies 48a, see Fig. 4, The outer end of rod 41 carries a bracket or coupling member 41a having a round opening or socket therein to receive the adjacent end portion of the rod 46. The rod 46 and consequently the leveling pan 45 carried thereby, are adjustable in and out transversely of the machine and the rod 46 is preferably held rigidly in the coupling member -4l'a by a lock screw or bolt and lock nut assembly, indicated at 411), Fig. 4. As seen in Figs. 3 and 4, the outer end portion 46a of the rod or shaft 65 is movably or pivotally connected at 452) to the pan 45. If desired, the small leveling pan assembly, including the pan 45 and the rods or shafts 45 and 41 may be removed, as a unit, from the supporting rod 31a by loosening the bolt and lock nuts 48a and sliding the cylindrical bearing or coupling member 48 off the end of rod 31a. Or, if the smaller leveling pan 45 and its associated parts are not required, the entire unit may be swung upwardly away from the surface N by loosening the lock bolt andnut assemblies 48a and, left to hang in space above said surface.

' The pair of leveling pans to, or one of said pans 48 and the smaller pan 45, whichever combination is being used, rest upon the newly laid surface N and the curb C, respectively, during normal operation of the machine and provide, in effect, a common fulcrum for both of the longitudinal control arms or rods 35. Therefore, any up and down movement of the material receiving and feeding unit I i and/or the runners 20, will be transmitted in considerable lesser degree to the leveling pans 40 or 45. In lieu of the pans, suitable rollers or other surface-contacting members (not shown) may be employed.

In normal operation over a given grade or surface which has been newly laid, the leveling and finishing unit i2 and the control member or leveling pans 4B and 45, whichever combination of the latter is being used, remain substantially in parallelism, as mentioned above. When, however, this parallel condition is changed through any variation in the grade line, there is provided electrical-1y controlled switch mechanism which will be automatically actuated to start the electric motors 28 to immediately raise or lower the leveling finishing unit i2, dependent upon the requirements in accordance with the type of variation in the old road surface, i. e. whether it be'a rise or depression in said surface, until the parts again resume their normal positions or condition in parallelism. Such electrically operated 'switch mechanism is shown in detail in Figs. 5

and 6 of the drawings. As seen in Fig. 1, a control switch box S is mounted upon the transverse frame member 2i below and adjacent to each of the rearwardly extending control arms or bars 35. Each of the switch assemblies S comprises a casing, shown as a Whole at 50, having a pair of horizontally disposed partitions or webs 5i and 52 therein which serve to divide the switch box into three compartments. A transverse shaft 53 extends through the side walls of the casing 56 and carries a normally horizontal oscillatable arm or member 54. The shaft 53 extends outwardly beyond a wall of the casing 50 and carries a fixed normally horizontal external arm 55. The outer end of the arm carries a block 56 which is provided with a vertical bore or hole 56a. This block 56 is preferably swivelly mounted on the end portion of the arm 55 to permit tilting of a rod or pin 51, now to be described. In other words, when the angularity of pin or rod 51 changes from its normal or vertical position as seen in Fig. 2, there will be no binding effect between'the parts. Extending through said bore is the normally upright or vertically disposed rod or pin 51 which is threaded at its opposite ends, the lower threaded end carrying an adjustable stop nut 58. The upper end of the rod 57 is threaded into the threaded base portion or boss of a U-shaped connecting member or coupling 69. The member 60 is pivotally connected by a pin 59 to a depending ear or projection iiia carried by a vertically disposed oblong frame member 6| through which the rearwardly extending control arm or bar 35 projects. Thus, the upright rod 51 carries or supports the members 60 and iii and has a sliding lit in the hole or bore 55a, see Fig. 5. Separate compression coil springs 52 surround the rod 57 above and below the enlargement 55. The inner ends of these springs find bearings upon said enlargement, with their outer ends bearing against the adjustable nut 58 and the boss of the coupling member 60, respectively.

As best seen in Fig. 5, the longitudinal control arm 35 is severed in the vicinity of the frame member 5i and its opposed and spaced end portions are welded, or otherwise secured at Bib, to the adjacent side faces or surfaces of a square or rectangular block Bic, the block thus becoming an integral part of the control arm 35 and being carried by and capable of movement therewith. The block Bic is provided with a vertical bore which is internally threaded to receive a vertically disposed externally threaded or screw shaft Bid which extends downwardly into the frame member 6!.

The frame member 5i carries at its upper end a fixed indexing disk Sie having a series of vertical holes or sockets fiif arranged in a circle adjacent its periphery. The screw shaft Eiid has fixed to its upper end a crank disk or wheel iiig carrying an operating handle 5! h. A hub portion or boss 6H on the crank disk Eig provides means for spacing said disk from the indexing disk file. A stop ring or member iiij, keyed or pinned at Bile to the screw shaft Sid prevents up and down movement of the crank disk and screw shaft relative to the frame member iii.

The handle Blh carries a depending pin 6i m and a surrounding compression spring which bears at its lower end against a stop Sin to normally maintain the lower end of the pin in en gagement with one of the holes or sockets iii of the indexing disk. When it is desired to turn or rotate the crank disk iiig in either direction relative to the indexing disk 6! e, the handle is lifted in an upward direction to release the pin from engagement with the hole or socket. The handle is now used to turn or rotate the crank disk and in turn rotate the screw shaft in either direction. Since the block Sic is a fixed part of the control arm 35, such rotation of the crank disk and screw shaft will serve to raise or lower the frame member 5i and the shaft or pin 51 to vary the position of the shaft 5'! with relation to the control arm 35 and to move the switch arms 54 and 55 to their normal or neutral hori- 2 ,144 was iontrl iaositib'nto compensate;- rorniflerexitgrade levels for which the finishing unitiilt i'andizithe levelingiens: 40 and 15 nrayslir z:adiustcdrv- The pressure which the sp ingsfl exert 'up'orr the one large'ment 55 f arm iiimay :be varied. by ad justing ithe nut: '58- to compensate for: ranyssuch' longitudinaladjustment'ofthe rod-0r pin 51: and its i-supported' frame rmember:v 6 l= :witlir relation to the control-arm;'which hasheen effected :by actuating the' crank :disk fi by {as mentioned above.

As-best seeninFig-r 1 of the drawingsyit is de-'. sirableto'provide -independent means for maintainin'g each-of the controlarms fi 5- in its proper position-or relationship ;with respect: to the-lolong frame member 6|; suchimeans, 1 as shown,- comprisesa bracket 80 carried by the rear channel 16 througnwhich-bracket a depending rod arextendsp The upper end-of therodth is threaded and held'in. the desired vertical-position' of -ad-.iustment by :-meansof lock *nuts. The lower end of the r0d=8k carries a loop-likeor oblong frame member Btthroughwhich-the control arm extends.-- A similar assembly is provided adjacent opposite sides oi the channel. lfifone for cachet the-control-arms s The unit 80-, 8l and 82, while, serving as guide meansifor maintaining the arm 35 in position against undue transverse movement ior' weaving, may also .serve as stop means to limit theupward and downwardmovement of the control. arm beyond predetermined points. andlthus serve as safety meansto prevent damage to the screw shaft'fil d and its. associated parts. 7

It willbe remembered that under. normal op:

. erating conditions, the COIltIOIfPflh-S or 45, 01:

any combination of .them..which is .beinggused, remain in parallelism withfthe leveling and finishing unit l2 and-when insuch position, the arms.

65 and 0f both of the switch assembliss are in their normal horizontal .or inoperative unneeessary hereini to descrihe rthem:.: more. "in detail:"- It will sumce w say l-that when thez arm Eli- 55 osciilalted bymovementlot thencon-trol arm 35 into position to; engage the contact: button. 63, the snap action .switchfmechanism 61 is immedi ate'ly operated to-start one oithe electric. motors 2813c raise-ordo werg as the case may begtheleveling Land: finishingxunitrtl 2.: When the arm 54 "is osciliated' -in the opposite direction into engagemeat with the button 69, thevsnap-action switch mechanism?! 2 QfUILCtiODIg immediately. to: :operate the "electric: motor in the-opposite direction and toi-ililrewise move the". leveling and finishing. unit 12 in a reverse direction.

As-soen as the" variation :in the old road surface which has caused the shifting of the unit fl2 has been-compensated: ior and'the 'levelingqpans and said unit have again assumed ltheir normal: positions insparallelism-pthevcontrol arms 35, through the medium/entire vertical shafts or pins 51,;will immediately move'the arms M -and: 55 :totheir normal horizontalpositlons releasi-ng ,the: contact buttonswwithwvhich .tlie arms-".54 have'bee'n: in contaet-to-openrthe switches and stop the electric motors -2 6;- It: will be understoodthat this action and operation: of: the rvarious associated parts :of the -machine' orriapparatus will occur automatically .whenever'a variation in the. old. roadsurface isencount'ered:by'the forward unit I l of the machine and. the: runners 20.

In Fig.7 there fist-illustrated: a diagramzofea conventional? electrical.- circuit 1 forelectrically connecting-tithe snap-actionswitches-16'! and 12 of each of the switch .units S "with 1 its respective electric motor .-26.-

From the foregoing it Will be seen that we have provided i-a pair -of sensitive and automatically positions, as shown.in..Fig'. 5." The function'of the springs 624s .to .maintain the arms '54 and 55norma1ly iin" their-horizontal or centered position and to also provide cushioningzmeans for said arms in' the event the controliarm 35 moves the rod or pinE'Flohgithdiiiallj.byond it predetermined point. Such'cushioning effect prevents any (possibility of damage. tolthe swit'chimechanismas will'be'presentlytdescribedi.

The upper web' or partition if of ithe .switch box carries a snap-action switch assembly com-5 prising: gtlcontact button or member Git-carried by ,a threaded member 61 which is' :fii'red td the web by lock'nuts. '65 and the snapeaction portion of the switch assembly, shown-as a whole at 61;

The web or partition. also carries an adjustable stop ,1 member 68 to --prevent movement oft-the switch arm- 54 'beyond a predetermined point. to prevent anypossibility of damage to thetcontact button. 63 on other elements oft-the snap-action switch assembly.

The-web or partition 52 carries-a similar sn ipe action switch g assembly comprisingra contact but). ton 69 carried by a threaded member 10 which is held in position with; relation to -the-web by :lock nuts It, andthe-snap-action portion of the switch-assembly,'shownas-a I-whole at .12; The Web'or' partition 52 also carriesani adjustable stop member::'|3 '-whioh= serves :to :prevent' movement of :-the switcharm 54 beyond a predetermined point and thus prevents damage to the FSWitCh contact button 69 and other elementsv-cfithe snap; action sswi-tchn'assemblys Sinceethe snap-action switoh' 'aSsemblie-s? are rot standards construction and urchazsedinr the -open marketg itris thong-ht operated normally open electric switchassemblies foroperating the electric motors 26- in either di-- rection, which-motors intturn drive nthamechanism previously described for. effecting the raisingor lowering of-the level-ingand finishing unit it! to compenate for any variation-in the-old'road surface "which-variation isstransmittedtfrom the front end of the machine, namely fnomtheunit II' and, runners -20 to the leveling and finishing. unit. Thus, by virtue ofour novel structure a desired Jand'predetermined grade for the finished surface .is automatically and accuratelymain' tained.v It willbe understood .th'at the control means or leveling pans 60or 45,'iwhichever are beingused for the-particular job being done, are set or adjusted at the desired grade level for the new suriacea'nd by such setting this level is automatically maintained during the travel of the road' surfacing machine 7 or apparatus. The switch'contact 'en'ga'ging arms or members 54 are also checke'd and "adjusted to their horizontal positions as seen in FigJE in accordance with the particular grade setting'of the leveling pans; The traction elements I 3 and the runner-skit substanti'allypreventany small or minuteirreg'ularities in the-ol'd road "surface from -affecting vthe positionmf the "material" receiving-and feeding unit 'I Larger-and sharp irregularities in the surface being COVId'Willi 'howeven-produce some vertical movement of the material receiving and feeding 'unit? lf Sdch -'vertical movementof this unit' has a tendency tomove'the "leveling and finishing"unit= [2, vertical-1y; andto-thereby cause any :sharp irregularities of the surface being covered tobe reflected in" the finished surface However; the \control means' above referred to operates 'zmtomatically '-'alongwith the leveling' andfifiishing unit I! to automatically control the level of said last-named unit to average out any sudden rises and depressions in the surface being covered as reflected inthe finished surface. While any sharp rises and depressions in the surface being covered will be reflected in the finished surface they will, however, be in the nature of gradual rises anddepres-sions which will be hardly noticeable so that the surface produced by the apparatus of our invention will be an exceedingly smooth and even riding surface by virtue of the automatic action of the elevating means for the leveling and finishing unit and the electrically controlled means for actuating the elevating means.

Having thus described our invention, what we claim is: l

1. Control means for a road surfacing machine in which the machine includes traction members and runners connected together, a material receiving and feeding unit and a leveling and finishing unit adapted to be drawn over a newly laid surface behind the first-named unit, and in which the machine includes electrically operable elevator means for raising and lowering said leveling and finishing unit at predetermined times; said control means comprising leveling members engaging the newly laid surface, control arms interconnecting the leveling members and runners, an electric switch assembly carried by said frame adjacent each of said control arms, and means carried by said control arms and connected to said switch assemblies whereby to operate the switch assemblies and elevator means upon movement of said control arms when said runners encounter a variation in the road surface to be paved. l 2. Control means according to claim 1 wherein the means carried by the control arms is manually adjustable with relation to said arms and includes cushioning means whereby to permit movement of the control arms beyond a predetermined point without damaging the electric switch assemblies.

3. In combination with the elevator means for a leveling and finishing unit of a road surfacing machine in which a control member is in contact with the newly laid surface and a movable control arm connects the control member with a forward portion of the machine; an electric switch assembly, said switch assembly comprising a housing carried by said unit and having a pair of snapaction switches therein, an oscillatable arm interposed between said switches and adapted upon movement to contact and close the same, stop members disposed at opposite sides of said oscillatable arm, a second oscil-latable arm disposed outside said housing and connected to the firstnamed arm for oscillating the same, and a cushioned connection between the outer end of said second arm for connecting the same to said movable control arm whereby upon contact of the forward portion of the machine with a variation in the surface to be paved the oscillatable switch arms are caused to actuate either of the snapaction switches to operate the elevator means to move vertically the leveling and finishing unit.

4. A combination according to claim 3 wherein said cushioned connection comprises an'upright shaft adjustably connected at its upper end to said movable control arm and having a slldable connection with said second oscillatable switch arm, and compression springs surrounding said upright shaft and engaging said second switch arm whereby to maintain the oscillatable switch arms normally out .of contact with said snapaction switches.

5. A road surfacing machine comprising a material receiving and feeding unit, a leveling and finishing unit disposed behind the firstnamed unit and including a pair of runners which are spaced transversely of the machine, electrically operable means for moving vertically the leveling and finishing unit relative to the receiving and feeding unit at predetermined times, and control means operatively connected with said electrically operable means and including a leveling pan resting on the newly laid road surface, a movable control arm interconnecting said pan and one of said runners, a normally open electric switch for actuating said electrically operable means, and means located intermediate the ends of the control arm for connecting the arm to the electric switch whereby to close the switch and operate said electrically operable means when the runner encounters a variation in the surface to be paved.

6. A power-driven road surfacing machine including traction members and runners engageable With the old road surface, a material receiving and feeding unit at the forward end of the machine, a frame structure located at the rear end of the machine and connected thereto to travel along with said machine, a leveling and finishing unit carried by and disposed below said frame structure, electrically operable elevating means carried by the frame structure and connected to said last-named unit for moving vertically the unit at predetermined times, and control means operatively connected with said electrically operable elevating means for operating said elevating means to move the leveling and finishing unit vertically'when the material receiving and feeding unit and the runners encounter a variation in the surface to be paved, said control means comprising a normally open electric switch mechanism, a leveling pan in engagement with the newly laid surface, and means connected to said frame for operatively connecting the pan and switch mechanism together for actuating said switch mechanism at predetermined times.

7. A road surfacing machine including powerdriven tractor means and comprising a material receiving and feeding unit adapted to travel over a surface to be paved, said machine also including runners engaging the surface, a leveling and finishing unit connected to said material receiving and feeding unit and including a screed and an oscillating cut-off bar, electrically operable means for raising and lowering said leveling and finishing unit, control means at the rear end of themachine having a portion adapted to ride upon the newly laid finished surface and connected with said receiving and feeding unit whereby upon contact of said last-named unit with a variation in the surface to be paved the electrically operable means is actuated to automatically move vertically the finishing unit dependent upon whether or not the variations in said-surface is a raised portion or a depression, and control arms interconnecting said receiving and feeding unit and said control means, said portions of the control means which rides upon the newly laid surface providing a fulcrum for said control arms during any positional variations thereof from normal.

8. A road surfacing machine comprising a material leveling member, means for supporting and adjusting said leveling member on the machine and including electrically operable means adapted to be actuated to move said leveling member to various vertical positions on the machine, means for supporting said machine for movement along the surface to be covered, and means for actuating said electrically operable means to automatically change the vertical position of said leveling member on the machine as the machine moves vertically in passing along over the surface to be covered, said means comprising a control member supported on the machine for vertical movement relative to the leveling member and adapted to ride on a surface having a predetermined grade line, an electric switch for actuating said electrically operable means and means for operatively connecting said control member to said switch so that said switch will be actuated to operate said electrically operable means to move said leveling member vertically whenever the leveling member moves vertically relative to the control member.

9. A structure according to claim 8 wherein said control member is supported on the machine for vertical movement at a point behind said leveling member and is adapted to ride on the surface produced by said leveling member, said control member being carried by the rear end of a lever arm, said arm having its forward end pivotally connected to the machine, and means located intermediate the ends of said arm for operatively connecting the arm to said switch.

10. A structure according to claim 8 wherein said control member is supported on the machine for Vertical movement at a point behind said leveling member and is carried by the rear end of a lever arm, said arm having its forward end pivotally connected to the machine, and means located intermediate the ends of said arm for operatively connecting the arm to said switch.

11. A structure according to claim 8 wherein said control member is supported on the machine for vertical movement at a point behind said leveling member and is carried by the rear end of a lever arm, said arm having its forward end pivot-ally connected to the machine, said switch being supported by said leveling member, an arm for actuating said switch and carried by said lever arm in spaced relationship thereto, and manually adjustable means for varying the distance between said leverarm and said switch-actuating arm.

12. Control means according to claim 1 Wherein the means carried by the control arms is manually adjustable with relation to said arms.

ARNOLD S. MILLIKIN. JOHN H. APEL.

REFERENCES CITED The following references are of record in the file of this patent: r

UNITED STATES PATENTS Number Name Date 1,769,521 Lamb July 1, 1930 1,779,799 Blum Oct. 28, 1930 2,140,105 Cluster Dec. 13, 1938 2,280,262 Purat Apr. 21, 1942 2,284,550 Adams May 26, 1942 2,295,519 Millikin Sept, 8, 1942