US2922345A - Apparatus for automatically leveling material in the building of roads and the like - Google Patents

Description

Jan. 26, 1960 A. G. MENTEs 2,922,345

APPARATUS FOR AUTOMATICALLY LEVELING MATERIAL IN THE BUILDING OF' ROADS AND THE LIKE Filed June 6. 1955 4 Sheets-Sheet 1 ATTORNEYS Jan. 26, 1960 A. G. MENTES 2,922,345

APPARATUS FOR AUTOMATICALLY LEVELING MATERIAL IN THE BUILDING OF ROADS .AND THE LIKE Filed June 6. 1955 4 Sheets-Sheet 2 INVENTOR. ALEXANDER G. MEN'TES ATTORNEYS Jan. 26, 1960 A. G. MENTEs 2,922,345

APPARATUS FOR AUTOMATICALLY LEVELING MATERIAL IN THE BUILDING OF ROADS AND THE LIKE 4 Sheets-Sheet 3 Filed June 6. 1955 mm mwa@ IN V EN TOR. ALEXANDER G. MENTES ATTORNEYS Jan. 26, 1960 A. G. MEN'rEs 2,922,345

APPARATUS FOR AUTOMATICALLY LEVELING MATERIAL IN THE BUILDING OF ROADS AND THE LIKE Filed June 6, 1955 4 Sheets-Sheet 4 [Il |l |I Z/Z Z/4 2/0 if 264 l: 99 20.5" 25g' I @j a T T- mmc?mxmxxxxxxmwx FIG. I3.

ff v INVENTOR.

ALEXANDER e. MENTES 206 BY 4 207 '.M

ATTORNEYS United States Patent() APPARATUS FOR AUTOMATICALLY LEVELING MATIIIJIKIL IN THE BUILDING OF ROADS AND Alexander G. Mentes, Hasbrouck Heights, NJ.

Application .lune 6, 1955, Serial No. 513,209

Claims. (Cl. 94-46) Ihis invention relates to an apparatus for automatically producing a level surface which is leveled in accordance with a predetermined level established in continuous fixed relation with the prescribed grade of roads and the like. The invention comprehends an apparatus having a leveling member for producing a level surface in the bed of a road and the like and in the material employed-in the construction thereof and which leveling member is movable in accordance with a predetermined guide level established by the requirement of the grade lof the road to automatically vary the elevation thereof.

In the construction of roads and the like stakes are set out along the terrain adjacent the site of the road on which the required grade of the road is marked together with the amount of excavation and/or lill required to convert the terrain to conform to the plan of the road. As the excavation and fill-in proceed constant checking is required with the markings on the stakes. This is done by sighting and checking the deviation of the work done from the markings on the stake to determine the progress of the work and the amountof excavation and/ or lill-in required. The checking is customarily done by the foreman having charge of the Ymachines employed in the excavating and filling-in and spreadingof the materials. When the excavating and/ or filling-in have been substantially completed and the bed of the road must be graded to substantial accuracy with the requirements of the grade set on the stakes, constant checking is required to complete the final excavating and/ or filling-in to establish the bed of the road. In order to carry out the last filling-in and grading, and spreading and paving operations it is frequently customary to insert stakes approximately 25 feet apart in order that constant checking with the grade marks on the stakes may be conveniently made. In order to overcome this constant checking with the grade marks and other information on the stakes the present invention provides grading and spreading apparatus with means for automatically leveling the terrain of the bed of the road and the materials used in the building thereof in accordance with a guide which is set at a level established by the grade for the finished road.

The invention is applicable to grading apparatus having a blade for excavating and illing-in earth and which blade is adjustable to various elevations. The invention is also applicable to apparatus for spreading broken stone, bituminous material and the like and which is provided with a leveling member or screed adapted to be set for spreading the required depth of material. In carrying out the invention the apparatus is provided with an arm which is adapted to engage a guide extending in continuous fixed relation with the site of the road. The arm is mounted on the apparatus and operatively 2,922,345 Patented Jan. 26, 1960 apparatus for leveling materials in the building of roads and the like in association with a guide established by the requirement of the grade of the road and with means carried by the apparatus and engaging said guide for leveling the material in accordance with the grade as the apparatus is moved.

With the foregoing and other objects in view, reference is now made to the following specification and accompanying drawings in which the preferred embodiments of the invention are illustrated.

In the drawings:

Fig. 1 is a view in side elevation of an apparatus for spreading material in the building of roads and the like which is shown in association with a continuous guide and having means disposed in engagement with the guide constructed in accordance with the invention for producing a level upper surface in materials spread by the apparatus.

Fig. 2 is an end view thereof.

Fig. 3 is a schematic longitudinal view of the apparatus with parts broken away to show the underlying features of construction.

Fig. 4 is a top plan view of the apparatus.

Fig. 5 is an enlarged view in elevation of one of the micro switches.

Fig. 6 is an end view thereof.

Fig. 7 is a fragmentary view showing vthe mounting for the solenoids and the four-way control valve.

Fig. 8 is an enlargedl top plan view of the arm and bracket support therefortogether with a schematic view l of the electric wiring and hydraulic layout.

connected with the leveling member for varying the Fig. 8A is a fragmentary sectional view taken approximately on line SA-SA of Figure 8.

Fig, 9 is an enlarged side view of the arm and support therefor.V

Fig. 10 is a side View of an apparatus embodying a modified form of the invention.

Fig. 11 is an enlarged fragmentary sectional view taken approximately on line 11-11 of Fig. l0.

Fig. 12 is an enlarged top plan View of the arm and bracket support therefor and showing the wheel at the end of the arm in engagement with a guide rail.

Fig. 13 is a schematic view of the wiring diagram and associated parts.

Referring to the drawings and more particularly to Figs. l to 9 thereof inclusive in which the invention is shown in its application to an apparatus for spreading broken stone, bituminous material and the like, the apparatus may be of any preferred construction andas illustrated includes a chassis 10 mounted on an endless track 11 at each side thereof which are trained about wheels 12 and 13 at the front and rear and are driven by a motor 14 such as an internal combustion engine.

The apparatus also includes an endless conveyor 16 mounted on front and rear shafts 17 suitably supported on the chassis 10 and driven by the motor 14. The conveyor 16 is located at the bottom of a hopper 18 in which broken stone or bituminous material is dumped to be fed through the rear of the apparatus for spreading the required depth and width thereof. The material is discharged from the conveyor 174 onto a screw 19 extending transversely of the apparatus from one side thereof tothe other and which is journaled for turning movement on the chassis 10. The screw is driven by a chain drive 20 operatively connected with the motor 14, onehalf of the screw having a right-hand blade and the other half having a left-hand blade for conveying and distributing the material from `the center of the apparatus I?.` road. The leveling member 22 is -termed a screed, and extends the full width of the apparatus and includes a vertically disposed front plate 23, end plates 24 and a bottom plate 25 which compressesthe material discharged by the conveyor and smoothsand levels-the top surface thereof with the movement of the apparatus..A In therh embodiment illustrated the leveling member 22 is affixed@-` at its ends to side arms 27 pivoted to the chassis 10 on pins 28. Each of the side arms 27 is composed of front and rear sections '29 yand 30 which are pivotally con-v nected together .in end to end relationon pins 31. The

end plates 24 of thelevelingmember 22 are secured ,I to the rear sections 39 and the rear sections together;

with the leveling member 22 have swinging movement about the pin 28 as -the center. Mounted on the bottom plate 25 is a column 33 which is slideable in a collar 34 affixed by bolts 35to `a plate or platform 36. Thev column protrudesrthrough an opening in the plate and through the collar and is provided with a rack 37 which 1 is engaged by a gear 38. The gear is secured to ashaft,

39 mounted for turning movement in a bracket 40 affixed y to the plate or platform 36 and ,is operatively connected by mitre gears 41 with a crank 42adapted to be turned forraising and lowering the plate or platform 36 with reference to the column.

In order that the leveling member A22 is automatically raised and lowered to produce a level top surface in the material discharged by the apparatus in accordance with` Y a predetermined level established by the prescribed grade of the road, the apparatus is provided with an arm 46 extending laterally outward from one sideof the Aap-y paratus and having a wheel or shoe 47 at the outer end thereof which is adapted to engage av guiderail 48 exu tending in continuousl relation to the site of the road..

and in xed relation with the Irequired'grade thereof or in other words any pointon the guide rail corresponds to the finished` grade ofthe-road at such point. The

arm 46 is pivoted to the plate 36 on pins 49 and is pivotness heretofore has created unevenness in the uppersur- Y face o f the ,material spread by the apparatus. This uneven movement of the apparatus is compensated forin the present invention by instrumentalities operatively connectedwith the inner end of the arm 46, and with hydraulic rams 53rand 54. The inner end of the Aarm 46 is movable yto different positions with the up and down movement of the apparatus and which functions to automatically elevate the leveling member 22 when the inner end of the arm 46 is moved to one of said positions and to automatically lower the leveling member 22Vwhenever the arm is moved to the other of said positions. Y

The rams 53 and -54 may be` actuated in any desired manner tor-aise and lower the leveling member 22. As

illustrated the rams include pistons 55 which are pivoted to posts 56 respectively aflxed to the channel sections 29. The pistons 55 protrude from the cylinders 58 which are pivoted tobrackets 59 respectively aflixed to the Y channel sections 30. The heads of the pistons 55 are.

arranged within the cylinders 57 between ports 60 and 61. `The rams .53 and 54 are hydraulically connected with an oil pump 63 through a four-way control valve.

65. The ports 60,and 6l of the ram 53 are connected by conduits 66and 67 with the ports at one end of the control valve 65 and the ports 60 and 61 of the ram 54 are connected by conduits 68 and 69 with the opposite endlof the lfour-waycontrol valve-65. f The four-way control valve 65 is connected with theV 4 l oil pump 63 by supply conduits 70 and by return conduits 71. The valve is controlled by two solenoids 75 and 76 having oppositely disposed armatures 77 and 78 connected with an actuating lever 79 for opening the ports for the flow of hydraulic fluid to and from the rams 53 and 54 thereof and for shutting olf the flow thereto. The actuating lever 79 is spring loaded and is normally maintained by the spring in neutral position. Thesolenoids are connected in electric circuits 80 and 81 respectively with a direct current generator82.` Interposed in the circuits 80 and 81 are micro switches 83 and 84 respectively. The circuit 80 is connected to two spaced switch terminals 85 -and 86 aixed to a bracket 87 mounted on the plate 36 and the circuit 81 is connected to two spaced switch terminals 88 and 89 affixed to said bracket 87 with the switch terminals respectively disposed in vertical alignment.

Aflixed to the inner end of the arm 46 are oppositely disposed switch blades 90 and 91. The switch blade.90 is adapted to engage between the switch terminals- 85 and-86 and the switch ,blade 91 isl adapted to engageV betweentheswitch terminals V88 and 89 for closing the circuits 80 and;81,respectively. It vwill therefore be understood that any movement of the apparatus or the arm 46.by which the. inner end of said arm -is swung upwardlyk to dispose the switch blade 90,between` the switch terminals 851and86 will' close the circuit 80 t0 Athereby energize the solenoid 75 and anymovement `of the ap-A paratus or the arm `46 by which the inner end of said arm is moved downwardly whereby the blade `91.,is moved i between the switch terminals 88 and 89 the circuit 81 will be closed to energize the solenoid76.

Y The solenoids175 and 76.are.aixed to an upstanding bracket 93 which is riveted or .otherwise aixed to the top 94 of the apparatus. is also secured to the bottom plate of the bracket 93 withvthe actuating lever 79 extending `upwardly ,therefrom and provided with outwardly extending arms 95 independently pivoted to the lever at 96.

The armatures 77 and 78 of the solenoids are mounted Y for reciprocatory sliding movement and in order to im-` f part movement to the control lever 79 when the solenoids are energized the armatures are pivotally connected to levers 97 and 98 respectively on pivot pins 99 and 100 with the lower ends of said levers pivoted to the arms 95 on pivot pins 99 and 100 respectively The levers 97 and 98 are pivoted to the bracket 93 on pivot pins 101 tively when the circuits are closed through thel switch ,i This results in alternately terminals and switch blades. making and breaking the circuit to the` solenoids whereby the flow of the hydraulic fluid to the rams will be byl a short impulse each time the circuit is closed by the actuation of the micro switch. It will be understood that each time either one of the circuits is broken byits micro. switch the actuating lever 79 will be moved by thespring (not shown). to close of the flow to the` hydraulic ram.. The pistons howeverwill move in small incrementsto adjust the leveling member so long as the circuits are closed respectively through the switch terminals and switch blade.

The micro switches 83 and 84 are of standard construction and include a normally open springswitchcontanecl within the bodyl03 which are arranged in the circuits 80 and 81 respectively. The spring switch (not shown) is adapted to be closed by aA reciprocatoryY plunger 104 having a roller 105 at. the outer end thereof andwhich i is engaged by a rotatable cam 106 driven byan electric motor 107 mounted on the top 94 of the apparatus.

The fours-,way control valve r,65

The* arm 46 consists of telescopically associated Ysecl screed 22 being connected with the apparatus by the pivot pins 28 is dragged along by the apparatus over the ma-N terial discharged by the conveyor 16 whereby thematerial is compacted and the upper surface thereof smoothened by the sliding thereover of the bottom plate 25 of the leveling member. The sections 29 and 30 of the side arms 27 being adjustable on the pivotal connections 31 permits of the adjustment thereof to control the thickness of the material being spread. When the pistons 55 are forced into the cylinders 58 of the rams 53 and54 so as to raise the rearmost portion of the leveling member, the thickness of the material being spread is increased and when the pistons 55 are formed outwardly from the cylinders 58 of the rams so as to lower the rearmost portion of the leveling member, the thickness of the material being spread is decreased. Thus the automatic actuation of the rams by means of the movement of the inner end of the arm 46 functions to move the leveling member 22 upwardly and downwardly to compensate for uneven traveling movement of the apparatus to thereby produce a level upper surface in the material being spread.

When not in use the leveling member is elevated out of contact with the road bed by hydraulic rams 114 located one adjacent each end thereof which are of standard construction in an apparatus of this character, the pistonsY 115 thereof being releasably connected with the top plate 116 of the leveling member while the cylinders 117. are secured to the apparatus frame as as 118. The

rams are hydraulically operated and manually controlled to raise and lower the leveling member and when the same is initially adjusted for spreading the material at a desired thickness the pistons 115 are released and the leveling member connected with the frame 11S by one or more chains 119 which are sufliciently loose to permit of the raising and lowering of the leveling member to vary the thickness of the material being spread.

The generator 82 is operatively connected with and driven by the motor 14 of the apparatus to provide a constant source of current supply for the circuits 80 and 81. The hydraulic pump 63 is operatively connected with the motor 14 of the apparatus for driving the pump so as to produce the required pressure in the hydraulic uid for actuating the rams 53 and 54. The rams 114 are suitably connected with a hydraulic pump (not shown) 198 and a front plate 199. The leveling member is dragged over the bituminous material indicated by the reference character 200 which functions to compact the material and level the top surface thereof with the forward movement of the apparatus. The leveling member 196 is affixed at its ends to aside arm 201 at each side of the apparatus which are connected with the chassis frame 202 by pins 203 extending through openings in the forward ends of the side arms and slidably engaging in vertical slots 204 of guide brackets 205 secured to the chassis frame 202 respectively. The side arms 201 are rigidly connected with the leveling member 196 whereby raising of the forward end of the side arms will tilt the leveling member to raise the rearmost portion of the leveling member to thereby increase the thickness of the material being spread and lowering the foremost end of the side arms will lower the rearmost portion of the leveling member 196 to effect a spreading of a thinner layer of material. The side arms are raised and lowered by means of racks 206 vsecured thereto and projecting upwardly through a guide slot 207 in an angle bracket 208 affixed to the side of the apparatus. The racks 206 are engaged by gears 211 driven by electric motors 210 through reduction gearing in the gear box 212.

As in the previous form of the invention, the leveling member 196 is automatically raised and lowered to produce a level top surface in the material discharged by the apparatus in accordance with a predetermined level established by the prescribed grade of the road. For this purpose, the apparatus is provided with a wheel or shoe 214 rotatably mounted on the outer end of an arm 215 which is adapted to engage a guide rail 216 extending continuously along the side of the road in lixed relation with the required grade thereof as in the previous form of the invention. The arm 215 is pivoted to a plate 217 as in the previous form of the invention. The inner end ofthe arm 215 is movable to different positions with the up and down movement of the apparatus to automatically elevate the leveling member 196 when the inner end of the arm 215 is moved to oneV of said positions and to automatically lower the leveling member 196 when the inner end of the arm is moved to the other of said positions. The arm 215 is provided with oppositely disposed switch blades 220 and 221, the switch blade 220 being adapted to engage between switch terminals 222 and 223 while switch terminals 224 and 225. The switch terminals are which is operatively connected with and driven by the motor 14 of the apparatus for producing the required pressure for actuating the said rams.

Instead of the hydraulic means forraising and lowering the leveling member 22 in the previous form of the invention, the leveling member may be raised and lowered by mechanical means as illustrated in the form of the invention shown in Figs. l0 to l2 inclusive of the drawings. The apparatus illustrated in this form of the invention is adapted for spreading bituminous material and the like and is similar in construction to the apparatus illustrated in Figs. l to 9 of the drawings. As in the previous form of the invention the bituminous material is discharged onto a screw 195 extending transversely of the apparatus, one half of which is provided with a right hand screw and the other half a left hand screw for conveying and distributing the material equally in front of a leveling member or screed 196. The leveling member 196 as in the previous form includes a bottom plate 197, end plates connected in an electric circuit 227 with the reversible motors 210 and with an electric generator 226 which is driven by any desired means for generating current supply for the motors. The switch terminals are so arranged that when the terminals 222 and 223 are closed by the switch blade 220, the motorsY 210 willrbe rotated in one direction and when the switch terminals 224 and 225 are closed, the motors will be rotated in the opposite direction. If desired, a micro switch 228 similar to the micro switches 83 and 84 in the previous form of the invention may be inserted inthe circuit 227 which functions to alternately make and break the circuit 227 when the circuit is closed through the switch blades respectively by which the motors 210 will be actuated by short impulses to raise and/or lower the side arms 201 by small increments.

The plate 217 is adjustably supported `by a column 230 mounted on the bottom plate 127 of the leveling member 196 and the plate 217 is adjusted in elevation by the turning of crank 231 similar tothe means provided for raising and lowering the plate or platform 38 in the previous form of the invention.

While the preferred forms of the invention have been shown in the drawings and described herein, it is to be understood that the invention is not so limited and may be carried out by other forms and mechanical means without departing from the purview of the invention.

What is claimed is: I l

1.Y An apparatus for leveling the upper surface of -material -in theV building3ofroads, 'in combination with a guide extending'in continuous relation to the site of the road and in fixed relation withY the required grade thereof, l

said apparatus including a-supporting structure for receiving the material to be spread on the road, means rollablyA supporting said structure, a material leveling member extending transversely of the apparatus and including any upwardly directed front plate, end plates and a bottom plate, side armseach including front and rear sections hingedly connected together, said front section` being hingedly connected with said supporting structure intermediate the rollable means at the sides respectively,-said material leveling member being rigidly afiixed to said rear sections fordownward and upward movement with the movement of 'said rear sections, an arm pivotally mounted on said apparatus to extend laterally outward from one side thereof with the outer end ofthe arm in continuous engagement with said guide for maintaining the outer end of said arm in xed relation with the required grade of the road and with the inner end of the arm movable to different positions with the upward and downward movement of the apparatus during traveling thereof over an uneven surface, hydraulically operated rams, said rams being connected to the confronting ends of said front and rear sections of the side -arms respectively for relative movement of said sections for moving the leveling member downwardly and upwardly, said rams being arranged in an hydraulic uid system having valve means for controlling the flow of the uid to actuate said rams, solenoids arranged in electric circuits for controlling the operation of said valve means, switch means arranged in said circuits respectively, and means carried by said arm and located adjacent the inner end thereof for actuating said switches to close said circuits with the movement of said arm to said different positions to thereby energize said solenoids to place said rams in operation to move said leveling member downwardly and upwardly respectively.

2, An apparatus for leveling the upper surface of material in the building of roads, in combination with a guide extending in continuous relation to the site of the road and in fixed relation with the required grade thereof, said apparatus including a supporting structure for receiving the material to be spread on the road, means rollably supporting said structure, a material leveling member extending transversely of the apparatus and including an upwardly directed front plate and a bottom plate, side arms each including front and rear sections hingedly connected together, said front section being hingedly connectedwith said supporting structure intermediate the rollable means at the sides respectively, said material leveling member being rigidly aflxed to said rear sections for downward and upward movement with the movement of said rear sections, an arm pivotally mounted on said apparatusto extend laterally outward from one side thereof with the outer end thereof in continuous engagement `with said guide for maintaining the outer end of said arm in xed relation with the required grade of the road and withithe inner end of the arm movable to different positions with the-upward and downward movement of the apparatus during traveling thereof over an uneven surface, hydraulically operated rams, said rams being connected to the confronting ends of said front and rear sections of the side arms respectively for relative movement of said sections for moving the leveling member downwardly and upwardly, said rams being arranged in an hydraulic uid system having valve means for controlling the flow of the fluid to actuate said rams, Ameans arranged in electric circuits for controlling the operation of said valve means, vswitch means 'arranged in said circuits reSPectively, and means carried by said arm and located adjacent Vthe inner end thereof for actuating said switches to close' said circuits with the movement of said arm to said different posi-V tions 4to thereby actuate said valve control means to place said ramsin operation to move said leveling member downwardly rand upwardly respectively.

3`. -An apparatus for leveling the upper surface of mate, rial in the building ofroads, in combination with a guide l extending fin continuous relation to the site of the roads and yin xed relation with the required grade thereof said apparatus Vincluding a supporting structure for receiving u the material to be spread on the read, means rollably supporting said structure, a material leveling member( extending transversely of the apparatus and including an upwardly directed front plate, end plates and a bottom 'i plate adapted for sliding movement on the material spread, side arms each including front and rear sections` hingedly connected together, said front section being hingedly connected with said supporting structure intermediate the rollable means at the sides respectively, said material leveling member being rigidly aflixed to said rear sections for downward and upward movement with the movement of said rear sections, a platform supported-by said bottom plate, an arm pivotally mounted on said platform to extend laterally outward from one side thereof with the outer end of said arm in continuous engagement with said guide for maintaining the outer end of said A,arm in xed relation with the required grade of the road and with the inner end of the arm movable to different positions with the upward and downward movementvof the 4apparatus during traveling thereof over an uneven surface, hydraulically operated rains, said rams being connected to the confronting ends of said front v and-,rear sections of the side arms respectively for relative movement ofsaid sections for moving the leveling member downwardly and upwardly, said rams being arranged in an hydraulic fluid system having valve means for controlling the flow of the fluid to actuate said rams, solcnoids arranged in electric circuits for controlling the 4 operation of said valve means, switch means arranged in said circuits respectively, means carried by said arm and located adjacent the inner end thereof for actuating said switches to close said circuits with the movement i of said arm to said different positions to thereby energize said solenoids to place said rams in operation to move said leveling member downwardly and upwardly respectively, and means for adjusting the height of said platapparatus including a supporting structure for receiving the material to be spread on the road, means rollably Isupporting said structure, a material leveling member extending transversely of the apparatus and including an upwardly directed front plate and a bottom plate adapted for sliding movement on the material spread, side arms each including front and rear sections hingedly connected together, said front section being hingedly connected l with said supporting structure intermediate the rollable means at the sides respectively, said material leveling member being rigidly affixed to said rear sections for downward and upward movement with the movement of said rear sections, a platform supported by said bottom plate, an arm pivotally mounted on said platform to extend laterally outward from one side thereof with theouter end thereof in continuous engagement with said guide for maintaining the outer end of said arm in fixed relation with the required grade of the road and with the inner end of the arm movable to different positions withl the upward andl downward movement of the apparatus during traveling thereof over an uneven surface, hydraulically operated rams, said rams being connected to the confronting ends of said front and rear sections ofther side arms respectivelylfor relative movement of said secf tions for moving the leveling member downwardl)r and' upwardly, said rams being arranged in an hydraulic uid system having valve means for controlling the ilow of the fluid to actuate said rams, means arranged in electric circuits for controlling the operation of said valve means, switch means arranged in said circuits respectively, means carried by said arm and located adjacent the inner end thereof for actuating said switches to close said circuits with the movement of said arm to said different positions to thereby actuate said Valve control means to place said rams in operation to move said leveling member downwardly and upwardly respectively, and means for adjusting the height of said platform for varying the height of the inner end of said arm.

5. An apparatus for leveling the upper surface of material in the building of roads, in combination with a guide extending in continuous relation along one side of the side of the road and in fixed relation with the required grade thereof, said apparatus including a supporting structure for receiving the material to be spread on the road, means rollably supporting said structure, a material leveling member extending transversely of the apparatus and including an upwardly directed front plate, and a bottom plate adapted for sliding movement on the material spread, side arms pivotally connected with said supporting structure intermediate the rollable members at the sides thereof respectively, said material leveling member being rigidly aixed to said side arms at the rear ends thereof for downward and upward movement with the swinging movement of said side arms, a platform vertically adjustably supported by said bottom plate to regulate and maintain predetermined spacings between said bottom plate and said platform, an arm pivotally mounted on said platform to extend laterally outward from one side of said apparatus with the outer end of said arm in continuous engagement with said guide for maintaining said outer end in iixed relation with the required grade of the road and with the inner end of the arm movable vertically to different positions with the upward and downward movement of the apparatus during traveling thereof over an uneven surface, power operated means operatively connected with said leveling member for moving said leveling member downwardly and upwardly, electrically operated means arranged in electric circuits for controlling the operation of said power means, switch means arranged in said circuits respectively, and means carried by said arm and located adjacent the inner end thereof for actuating said switches to close said circuits with the movement of said arm to said dilferent positions to thereby place in operation said electrically operated means to actuate said power means for moving said leveling member downwardly and upwardly respectively.

References Cited in the tile of this patent UNITED STATES PATENTS 2,043,413 Knox et al. June 9, `1936 2,125,590 Smallwood Aug. 2, 1938 2,295,519 Millikin et al. Sept. 8, 1942 2,441,532 Millikin et al. May l1, 1948 Y 2,491,275 Millikin Dec. 13, 1949 2,591,502 Bohannan et al. Apr. 1, 1952 2,597,221 Barber May 20, 1952 2,636,290 Bell Apr. 28, 1953 2,720,716 White ..-e Oct. 18, 1955

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