US2169987A - Method and apparatus for building roads - Google Patents

Description

Aug. 15, 1939. J. H. MOSEL umnon AND APPARATUS FOR BUILDING ROADS Filed April 15, 1936 3 Sheets-Sheet 1 IN VEN TOR. Jaszp/i H M0s e/.

A TTORNEYS.

Aug. 15, 1939. MOSEL 2,169,987

METHOD AND APPARATUS FOR BUILDING ROADS Filed April is, 1936 s Sheets-Sheet 2 INVENTOR. Joseph /7! Mosa/ BY Mr W ATTORNEYS.

Aug. 15, 1939.

J. H. MOSEL METHOD AND APPARATUS FOR BUILDING ROADS Filed April 15, 1936 3 Sheets-Sheet s INVENTOR. Joseph H Nose/ A TTORNEYS.

Patented Aug. 15, 1939' Joseph H. llfosel, Columbus, Ohio, assignor to The Jaeger -Machine Company, Columbus, Ohio, a

corporation of Ohio Application April 13, 1936, Serial No. 74,059 23 Cl'aims.- (CI. 94-46) My invention relates to method and apparams for building roads; It has to do, more paring roads with such materials as bituminous mixes or other relatively low cost materials now commonly used. It relates more particularly to a machine for passing over materials previously applied to thesurfaceto be treated and forming therefrom a complete layeror slab; i

One of the objects of myinvention is to provide a machine which is adaptedto forma road sur face from material previously applied-infront of the machine on the surface tobe treated, the

machine being adapted to thoroughly mix-the material, eifectively'spread it across-the surface to be covered and to form therefrom a layer or slab of the desired thickness, and contour and Y having straight edges, in one pass'over said material.

Another object of my invention is to provide a machine of the type indicated with which it will be possible touse road materials, especially of the bituminous mix type, which will quickly'set so as to avoid "picking -up'by cars while trailic is maintained, which is made possible because of.

the fact that a single pass by'the machine over the material is all that is necessary to form the completed road surface. V 80 Another object of my invention is to provide a machine forforming low cost roads which will form the complete layer or slab with straight edges without the use of expensive side forms that are set along the edges of the surface to be 35 covered.

Another object of my invention is to provide a machine of the type indicated which is particularly adaptable to spreading of material over an old road bed or over a roughly graded or other 40 rough surface, the'apparatus being of such a nature that the longitudinal irregularities in the "surface being covered will be practically eliminated in the surface produced by the machine and, consequently, the machine will produce a 45 surface which is very even and which will not be llwavyfl Another object of my invention is to provide a machine of the type indicated which is so constructed that material previously dumped on the 50 surface to be covered will be more thoroughly mixed by a single pass of the machine over the material than with a large number of passes with machines of prior art types. 7

Another object of my invention is to provide a to method and machine which is of such a nature that it is particularly useful in applying bituminous retreading materials to an old road surface ticularly, with a'machine which is particularly adaptable to building low cost roads or retreadand being of such a type that the tack coat may be efficiently applied to the old road surface substantially-simultaneous with the application 5 of the retreading material .thereto.

- In its preferred form my invention contemplates the provision of a machine which is composed of two substantially independent units 1 but which are operatively connected together and 10 which operate in conjunction with each other. One of these units embodies a mixing and spreading unit which thoroughly mixes the material, which has been previously applied to the surface to be covered, and which spreads the material 15 across the surface to be covered. v This unit thoroughly mixes the material and effectively spreads 1 it in one pass over the material. This unitpreferably embodies a comparatively narrow mixing box in which a plurality of pug mills are disposed 20 and means "for gathering in the material and conveying it into the mixing box where it is thoroughly mixed. It also includes apug mill which 7 is disposed behind the mixing box-and extends s'ubstantially'across the machine which also aids 25 in mixing the material but, in addition, serves to 'spreadit'laterally'across the surface to be covered.

The secondlunit is a finishingormolding unit and embodies a pair of longitudinally extending runners of considerable length which carry a finishing member, which takes the form of a strike-off blade, substantially midway between the ends of the runners. This finishing unit is connected to the mixing and spreading unit, the mixing and spreadihg"unit being disposed laterally within the runners, by means of connections which permit the mixing and spreading unit to float vertically relative to the finishing unit. The runners of the finishing unit limit lateral 40 spreading of the material produced by the mixing and spreading unit and, consequently, produce straight edges on the layer of material spread by the machine. The finishing member or strike-oil? blade carried by the'runners operates upon the material previously spread by the mixing and spreading unit and serves to level said material to the proper thickness and to produce the proper contour on the surface of the layer.

This application is a continuation in part of my copending application's Serial No. 753,210, filed November 15, 1934, and Serial No. 759,928, filed December 31, 1934.

The machine is preferably so constructed that as it advances through the material previously 66 applied to the surface to be covered, it removes the material from certain portions of said surface, applies a tack coat to said portions of said surface, and then spreads the material over the tack coat", all of these operations being accomplished v substantially simultaneously.

The, preferred embodiment of my invention is illustrated in the accompanying drawings wherein similar characters of reference designate corresponding parts and wherein:

Figure 1 is a perspective view of a machine constructed in accordance with the principles of my invention.

Figure 2 is a perspective view, more or less dia grammatic, of a portion of the machine illustrated in Figure 1.

Figure 3 is a side elevation of the machine illustrated in Figure 1.

Figure 4 is a detail in side elevation of the means for adjusting the wheels which support the mixing and spreading unit.

Figure 5 is a plan view of a portion of the machine illustrated in Figure 1 illustrating how the material passes through the mixing and spreading unit.

Figure 6 is a longitudinal section taken substantially through the center of the portion of the machine illustrated in Figure 5.

Figure 7 is a detail in longitudinal section illus trating the pug mill disposed at the rear of the mixing box and a bafile plate disposed adjacent thereto which controls flow of material rearwardly from the mixing box.

Figure 8 is a transverse section through a runner showing a modification.

. With reference to the drawings and particularly to Figure 1, I have illustrated my machine as comprising mainly a mixing and spreading unit I, and a finishing and molding unit 2. These two units are substantially independent of each other but are operatively connected together and cooperate with each other to produce the finished layer or slab of material. The mixing and spreading unit I has its rear end disposed laterally within the finishing or molding unit 2 and extends forwardly ahead of the forward end of said finishing and molding unit, as indicated in this figure.

The mixing and spreading unit The mixing and spreading unit I comprises a frame 3 which is suitably fabricated of a plurality of longitudinally extending beams l and laterally extending beams 5. The forward end of this frame is supported on a wheel 6 while the rear end thereof is supported on a pair of wheels I. The rear wheels 'I are not free to turn but the front wheel 6 is a caster wheel which may rotate through an angle of 360 degrees. However, the rear wheels may also swivel and may even be steered, if desired.

I provide means for adjusting the wheels 6 and I vertically relative to the frame in order to raise or lower the frame. The means for adjusting the wheel 6 and looking it in adjusted position is illustrated best in Figures 1 and 4. The

front wheel 6 is carried by a bifurcated arm 6 I which has a pin 9 formed on its upper end that is rotatablymountedin a vertically disposed sleeve III. The sleeve III has a rearwardly extending arm I I integrally connected to its lower end. The rear end of this arm II is pivoted to the frame 3 as at I2. ward end pivoted to the upper end of the sleeve It as at I 4. This bell crank lever is pivoted to A bell crank lever I3 has its for- I a support on the frame 3 as at I5. The lower end of the arm I6 of the bell crank lever has one end of a tension spring I! connected thereto as at 18. The opposite end of spring I! is connected to a bracket on the frame 3. Adjacent the up- 5 per end of sleeve ID and integral therewith is an arcuate rack IS. A pinion 26 keyed on shaft 2I (Figure 1) meshes with this rack. One end of the shaft 2| is supported by a support 22 on frame 3 and the other end is supported in a worm and gear unit 23 supported on frame 3. The worm and gear unit 23 is operable by a shaft 24 extending to the rear of the mixing and spreading unit and being rotatable by a hand wheel 25.

It will be apparent that with this mechanism the frame 3 may be adjusted vertically relative tothesurface to be covered. The wheel 6 may be adjusted relative to the frame 3 and locked in adjusted position merely by operating hand wheel 25 which operates the worm and gear mechanism 23. This in turn rotates the pinion 20 which meshes with rack I9, carried by sleeve I0, and, consequently, moves the sleeve vertically. When the sleeve I0 is moved vertically the arm I I which is rigidly securely thereto will swing about 5 the pivot point I2. The tension spring I! is provided for counterbalancing the weight of the mixing and spreading unit so that the weight of the unit will not cause binding of pinion 20 with rack I9 and to aid in raising the frame on the 3( wheel. It will be apparent that the weight of the mixing and spreading unit will tend to cause the sleeve I0 and the integral arm II to swing upwardly about the pivot point I2. However, the

tension spring ll tends to cause the bell crank 3 lever to swing about pivot point I5 and its forward end to swing downwardly which in turn tends to move sleeve IIl downwardly and cause the integral arm II to swing downwardly about the pivot point I 2. In other words, the spring I1 I and associated parts serve to exert a force which opposes and neutralizes the gravity force produced by the weight of the mixing and spreading unit.

of the wheels I relative to the frame 3 is exactly the same as that just described for adjusting the wheel 6. Furthermore, identical counterbalancing means is associated with each of these wheels.

The mechanism for adjusting one of the wheels 5 'I is operable by a hand wheel 25a while the mechanism for adjusting the other wheel 1 is operable by a hand wheel 25b. It will be apparent that each of the wheels is vertically adjustable independently of the others. I

On the front of mixing and spreading unit I a pair of plow blades 26 are disposed. These plow blades converge at their forward ends and rearwardly diverge as indicated best in Figures 1 and 2. The plow blades have their rear ends 6 rigidly secured to the foremost transverse beam 5 of the frame 3. as at 21. It will be apparent that these plow blades 26 are disposed in front of the front wheel 6. When the machine moves through the material to be mixed and spread, i

The mechanism for vertically adjusting each 4 cated, the pivot pin 32 may be disposed in any of the vertically spaced openings 33. A removable pin 34 normally prevents the coupling 29 from pivoting about the pin 36. The machine may be drawn along by a tractor .or other power unit connected to the forward end of the draw bar 3|. The draw bar will normally be prevented from swinging laterally and, consequently, this will insure that the machine will be drawn along in a straight line and will not wobble from side to side.

Gathering wings 35 are disposed on each side of the mixing and spreading unit adjacent the forward end thereof. Each of these gathering wings '35 comprises a longitudinally extending forward section 36 and an inwardly extending rear section 31. The two sections 36 are substantially parallel with each other. They extend from a point slightly forward'of .the foremost ends of the plow blades 26 to a point slightly rearward of the rear ends thereof. These gathering wings are suitably secured to the forward end of the frame 3 as indicated. It will be apparent that a space 36 is provided between the rear end of each plow blade 26 and the adjacent section 36 of the gathering wing,-through which material may pass rearwardly.

As previously indicated, the rear sections 31 of the gathering wings converge towards each other. At their rear ends they are connected to the side walls 39 of what may be termed a mixing box 46. This mixing box 46 is open at its top and bottom and is formed by the walls 39 which are vertically disposed plates that extend longitudinally of the machine and are suitably secured to the frame 3 thereof. The ground or old road surface being covered serves as a bottom for the box 46. It will be apparent that the mixing box 46 is comparatively narrow, being substantially half as. wide as the frame 3. Adjacent the forward end of the mixing box 46 a pug mill 4| is disposed. Adjacent the rear end of the mixing box a second pug mill 42 is disposed. Each of these pug mills embodies a rotatable shaft 42a having a plurality of small blades 42b extending radially therefrom. These pug mills are adapted to thoroughly agitate and mix the material that passes rearwardly into the mixer box 46.

Directly behind the pug mill 42 is a baflle plate 43 which is disposed within the rear end of themixing box 46. This bailie plate has its forward end pivoted at 44 and at each end is provided with adjustable bolts which extend through arouate slots 45 formed in the side walls 39 of the mixer box 46. This bafile member 43 may be adjusted in any desired inclined position and locked in such position. It is adapted to control and limit movement of the material from the rear end of the mixer box 46. If the material being mixed is of such a type that it passes too freely through the'mixing box or if there is only a comparatively small amount of such material, due to the fact that a thin layer is being spread by the machine, the baflle 43 may be adjusted until it is almost vertical in order to retard movement of the material from the mixer box and therefore insure that it will be thoroughly mixed before it leaves the rear end of the mixer box. If there is a large amount of the material in the mixing box, due to the fact that a comparatively thick layer is being spread by the machine, or

if the material is of such a type that it does not freely pass through the mixing box, the baflle member 43 may be set into substantially horizontal position or may even be entirely removed.

In other words, the baffle member may be. ad-

justed into various positions to meet various conditions.

0n the inner surface of each side wall .39 of the mixing box and at the extreme rear end thereof is disposed a rearwardly and inwardly extending diverting blade 46. Supported on one. of the transverse beams 5 of the frame 3 adjacent the rear end of the mixing box 46 is a rudder member 41. This rudder member is pivoted so that it may be swung laterally. The forward end of the rudder extends to a point between the diverting blades 46. The rear portion of the rudder extends reawardly a considerable distance. This rudder member merely embodies a vertically disposed plate which is of substantially the same height as the side walls 39 of the mixing box. It'is'provided so that the amount of material which is fed to either side of the surface being covered after it leaves the mixing box, may be controlled and varied at will. As indicated in Figure 1. the rudder 41 may be controlled by a shaft 48 which has its end threaded through a block pivoted to the upper end of the pivot pin 49 of the rudder as at 56. The shaft 46 is connected to a hand wheel 5|. hand wheel 5i, the rudder may be rotated into any position desired and locked in adjusted position.

At the extreme rear end of the mixing and spreading unit I a third pug mill 52 is disposed. This pug mill is practically the same as the other pug mills but is also adapted to spread the material laterally across the surface to becovered. It will be noted that the pug mill 52 extends'entirely across the mixing and spreading unit. The blades of this pug mill 52 are helically disposed and are so arranged that the pug mill comprises right and left-hand sections which feed the material towards the right and left respectively. A plate 52a having its lower edge spaced slightly above the axis of pug mill 52 is provided for keeping the material agitated by said pug mill from flying upwardly.

The pug mills 4l,-42 and 52 are all preferably rotated in a counterclockwise direction (Figure 6). It is desirable to rotate the pug mills in this direction in order that they will tend to throw the material forwardly rather than'rearwardly which would occur if they were rotated clockwise. By rotating them counterclockwise, more thorough mixing is insured since passage of the material through the mixing box will be delayed. However, they maybe rotated clockwise, if desired. The means for rotating these pug mills is indicated best in Figures 1 and 2. I preferably provide a gasoline motor 53 which by means of a sprocket and chain drive 54 drives the pug mill 4!. By means of a sprocket and chain drive 55 from the pug mill 4i to the pug mill 42,

the pug mill 42 is rotated. Furthermore, by

terial by a tractor or other power unit. The

front wheel 6 is so adjusted that the lower edges By rotating 2 wheel 6. These plow blades will spreadthe material laterally. However, lateral movement of the material will be limited by the sections. 36 of the gathering wings 35. The material will pass rearwardly through the openings 38 between the plow blades and the gathering wings andwill then be guided inwardly towards the center of the machine and into the forward end of the mixing box 40.

Since the mixing box 60 is comparatively narrow, the material through which the machine advances will be constricted. This is a desirable feature. The material through which the machine passes and which is previously applied to the surface to be covered is usually spread over said surface in a layer which is only a few inches thick. This layer would be difficult to mix because it is so thin unless means were provided for gathering it in and concentrating it into a comparatively narrow space. My machine does this. The material is gathered in by the plow blades 26'and gathering wings 35, being preliminarily mixed by such members, and is fed into the mixing box 40. In other words, the material is constricted so that when it is in the mixing box it will form a comparatively thick layer which may be more thoroughly mixed.

JWhEll the material enters the mixing box 40, the first pug mill ll will violentlyagitate the material, will break up lumps, and will thoroughly mix the material. The material is forced rearwardly through the mixing box 40 until it reaches the second pug mill 42 where it will again be thoroughly mixed. As previously stated, the baffle member 43 will control the length of time that the material remains in the mixing box. As the material. leaves the rear end of the mixing box, the rudder 41 may be adjusted as desired to the amount of material fed to either side. The material will feed rearwardly until it reaches the pug mill 52 which will again remix it but will, in addition, feed the material laterally so that it will be spread across the entire surface being covered.

Thus, the material is thoroughly mixed during one passage of the machine over and through the material. Furthermore, the material is effectively spread across the surface to be covered.

With this machine, the tack coat may be easily applied to the surface to be covered substantially simultaneous with the application of the layer of material thereto. It will be noted in Figures 1 and 5 that I have provided a perforated pipe 51 behind and between the plow blades 26.. This perforated pipe is adapted to be connected to a source of supply of liquid bitumen or'other suitable substance adapted to form the tack coat. The pipe 51 is of such a length that it will extend across the space cleared by the plow blades 26. It will be apparent that the plow blades clear away a path through the material being spread and mixed. Since the pipe 51 is disposed directly behind blades 26, the

tack coat will be applied to the surface from which the material has been cleared by the plow blades 26.

I also provide a perforated pipe 58 at each side of the machine. Each of these perforated pipes 66 extends from the side wall of the mixing box outwardly to a point in line with or past the section 36 of the gathering wing. It will be apparent that the sections 31 of the gathering wings will clear paths at each side of the machine through the material previously applied to the surface to be covered. Since the pipes 66 are disposed immediately behind the sections 31, they will cover the portions of the surface which have been cleared of the material by the section 31 with a tack coat.

Thus, it will be apparent that the pipe 61 will cover the center portion of the surface to be covered with a tack coat" while the pipes 68 will cover the lateral portions of the surface to be covered with the tack coat". The plow blades 26 and the sections; 31' of the gathering wings are so arranged relative to each other that the entire surface to be covered will be cleared of the material for a sufiicient length of time to enable the tack coat" to be applied. The pipe 61 and the pipes 58 are so arranged relative to each other that the entire surface will be covered with the "tack coat.

As previously stated, the plow blades 26 clear a path for the front wheel 6 so that this wheel will operate upon the surface to be covered. However, the rear wheel 1 will also operate on the surface to be covered, since the portions 31 of the gathering wings 35 will clear paths for these wheels. It will be noted that the wheels 1 are disposed closely adjacent the rear end of the spreader box 46 and laterally outside of the side walls 39 thereof. Since the material is gathered into the spreading box and the wheels I are arranged as indicated, the material will feed back between the wheels, and the wheels will The finishing and molding unit The finishing and molding unit 2 comprises a pair of longitudinally extending runners 59. These runners are comparatively long so that they will slide over a rough surface and will bridge the irregularities thereof and, consequently, will not move vertically to any considerable extent. These runners are adapted to serve as side forms to limit spreading of material by the unit I, They are adapted to form straight edges on the layer or slab produced by the machine. Each runner 59 embodies avertically disposed plate with a flat runner surface on its lower edge. Its forward edge is upturned as at 60 so that it will not dig into the surface over which it slides,

The runner members are spaced apart sufliciently to permit the rear end of the mixing and spreading unit -I to be disposed therebetween. They extend forwardly a considerable distance past the -rear end of the mixing box 40 and over lap the side walls thereof. Substantially midway between the ends of the runners vertical supports 6| are rigidly secured thereto. The upper ends of these supports 6| are joined together by means of a transversely extending beam 62. Thus, the members 6| and 62 serve to join the two runner The runner members 58 are adapted to carrya member which finishes the surface produced by the machine. This member is carried substantially midway between the ends of the runners.

10 Since the shing member is carried .by the runners which bridge the irregularities in the surface over which they operate, the irregularities in the rough surface will not be reflected in the surface produced by the machine,

15 'The finishing member carried by the runners comprises a strike-off blade orscreed 64. This strike-off blade is suspended from the beam 62 by means of shafts 65, one of which is disposed adjacent each end thereof. Each of the shafts 65 zo is rotatable by a hand wheel 66 and is connected to the strike-off blade 64 in such a manner that upon rotation thereof the end of the strike-oil blade will be moved vertically, This may be accomplished by having the lower end of the shaft 25 threaded into a member carried by the strike-off blade. Thus, either end of the strike-off blade may be adjusted independently of the other. The lower edge of the strike-oil blade is provided with any suitable means (not shown) for varying the 80 crown of the surface finished thereby. The mixing and spreading unit I is so disposed relative to the finishing and molding unit 2 that the strikeofi blade 64 is disposed directly behind the pug mill 52. 38 The strike-off blade 64 has vertically adjustable gates 61 disposed adjacent each end thereof. These gates 61 are slidably mounted in suitable guides on the strike-off blade for'vertical adjustment relative thereto. When the strike-ofi blade 40 is vertically adjusted the gates 61 will move therewith. However, the gates are also capable of independent vertical adjustment relative to the strike-01f blade. To accomplish this a link 68 has its outer end pivotally .connected to the upper 45 edge of the gate 61 as at 69. Intermediate its ends the link is pivotally connected to a bracket on'the upper. edge of strike-ofi blade 64 as at 18. Its inner end is pivotally connected as at II to a block to which the lower end of a shaft I2 is 50 threaded. This shaft 12 is adapted to be rotated by means of a hand wheel I3. It will beapparent that when hand wheel 13 is rotated, the link 68 will pivot about the point I and will raise or lower the gate 61 relative to the strike-off blade. 65 The gates at the end of the strike-ofi blade are provided to permit material to bleed rearwardly Past the ends thereof when desired.

At the extreme rear end of each of the runners 59 an adjustable blender wing I4 is disposed. One 60 end of the wing I4 is mounted for vertical movement in a support 15 secured to beam-63. The

other end is mounted for vertical movement in a support 16 secured to the rear end of the runner. These blender wings extend outwardly and rear- 65 wardly as indicated, Each end of the blender wing may be adjusted by means of a screw adjustment I1. Indicating means 18 is preferably provided for indicating the height .of the blender wing. On each support I6 a vertically adjustable 70 gate I9 is disposed in front of the blender wing I4 in order to permit material to bleed out past the runner 59. This gate 19 may be adjusted by meansof a screw adjustment 88.

The gates 61 and the blender wings I4 are pro- 7'5' vided mainly for use when the machine lays the road surface in twoor more'courses. When the first course is laid they are not used. However, after the first course islaid and a second course is being laid adjacent thereto, the blender wing at that side where the edges of the two courses 5 meet is used in order to get a perfect joint between the two courses. The gate'B'I at that sideis raised to permit a quantity of material to feed past the end of the strike-0E blade. The blender wing ll then spreads such material laterally behind the runner member and levels off said mate rial, producing a proper joint between the two courses.

In Figure 8 I show an angle iron 58a attached to the lower surface of the runner. It is so disposed that its vertical flange is substantially flush with the inner surface ofthe runner.- This flange on the angle iron cuts through loose material so that the flat surface of the runner will not ride on such loose material and it assists in grip- 20 ping the ground to prevent side sway.

The means for connecting the two units together The mixing and spreading unit I is connected to the finishing and molding unit 2 in such a manner that the mixing and spreading unit may move vertically without having any effect whatsoever on the unit 2, In other words, the unit I is free to float vertically relative to the unit 2. Although it will be apparent that vertical movement ,ofthe mixing and spreading unit I will be minimized because of the fact that all the wheels which support it will operate upon the surface being covered rather than upon the material ap- 5 plied' to said surface, the surface being covered is sometimes comparatively rough and is usually wavy. Consequently, it is desirable that vertical movement of the mixing and spreading unit resulting from rough and wavy conditions of said 4 surface be precluded from effecting corresponding vertical movement of the strike-off blade carried bythe finishing and molding unit. Consequently,

as previously stated, I provide connections between the mixing and spreading unit I and the molding and finishing unit 2 which permit relative floating movement between these two units.

The main elements for connecting these two units together comprise pull rods 8| disposed at each 'side of the machine. The rear end of each of these rods is pivotally connected to the upper edge of the runner adjacent the point where the strike-off member is located as at 82. This rod extends forwardly almost to the forward end of the runner at the point where it is connected to the spreading and mixing unit. It is pivotally connected to a. shaft 83 which extends laterally from the frame 3 as at 84. The outer end of this shaft 83 is free to move vertically in a slot 85 formed in a bracket 86 secured to the runner. go A cushion spring 8'! is provided for cushioning vertical movement of the pivot point 84. It will be apparent that as the mixing and spreading unit I is drawn along, it will pull along the finishing unit by means of the pull rods 8|. Further- 55 more, it will be apparent that with this connection the mixing and spreading unit may move vertically without affecting the molding and finishing unit. 1

In order to prevent relative lateral movement between the two units I provide the following structure. Adjacent the forward ends of the runners, rods 88 are disposed at opposite sides of the machine. The inner end of each of these rods is pivotally connected to the wall 39 of the mixing 1;

box as at II. The outer end of each rod fits intothat the members SI and 92 and the rods ll and forks OI will all cooperate to prevent relative lateral movement between the mixing and spreading unit and the finishing unit. This will insure that the runners will function to produce straight edges on the road. However, it will be apparent that these members will not interfere in any way with the floating action between the two units.

At the rear end of the frame 3 and at each side thereof a bar 93 is. pivoted thereto as at N for vertical swinging movement. These bars durins operation of, the machine are normally in the position indicated in Figure 1. When these bars are swung upwardly they are adapted to lie beneath and contact with lugs 95 disposed on beam 12 of the finishing Luiit. These bars are provided so that the finishing unit may be supported on the mixing and spreading unit for transportation when desired. It will be apparent thatsthe bars may be swung upwardly with their ends beneath lugs 95. Then if the wheels 6 and i are adjusted vertically to raise the frame 3 sumciently, the runners will be raised out of contact with the ground. Both units will then be supported on the wheels 6 and 'l for movement. The forward ends of the runners will be supported on the frame 3 by means of the shafts 83 contacting with the upper ends of the slots 05 in brackets 86 secured to the runners.

The operation of the entire machine As previously indicated, this machine is particularly useful in mixing and spreading bituminous mixes and forming therefrom a completelayer or slab. In using the machine, rough stone or other suitable material is preferably first roughly spread across the surface to be covered. The machine is then properly adjusted by adjusting the wheels 8 and I so that the plow blades 26, gathering wings 35, and the side walls of the mixing box will lightly contact withthe surface to be covered. The strike-off blade 64 is adjusted vertically to the proper extent to produce a layer of material of the desired thickness. Then the entiremachine is pulled over and through the material by means of the draw-bar 3| which-is connected to a tractor or other power unit.

portion of the surface by means of the pipe 51.

The sections ii of the gathering wings limit the spreading of the material by the plow blades and the sections 31 thereof gather the material inwardly and direct it into the forward end of the spreading box. Also, the portions 31 clear paths in the materialso that the wheels I may operate on the cleared surface and so that the "tack coat, 'may be applied to the sides of the surface by means of the pipe 58. As previously stated, the mixing box is comparatively narrow so that the be more thoroughly mixed since it will be concentrated into a narrower but deeper mass. The pug mills 4i and 42 will thoroughly mixthe material during its passage through the mixing box. After the material leaves the'rear end of the mixing box it passes to the pug mill and spreader I! which spreadsi it laterally across the surface to be covered. The amount of material. supplied to each side of the surface to be covered may be governed by means of the rudder 41. It will be apparent that the material previously applied to the surface to be covered is cleared from the surface, the tack coa is applied to the surface, the material is thoroughly mixed and then is respread over the surface, all of these operations occurring substantially simultaneous during passage of the machine through and over the material.

The strike-off blade of the finishing unit is dis posed directly behind the pug mill 52.- The pug mill again mixes and forces the material beneath the strike-off blade. The strike-off blade levels off the material to the proper thickness and imparts the proper contour thereto. The runners 59 of the finishing unit serve as side forms to limit lateral spreading of the material and to form straight edges on the layer or slab of material produced by the machine. The mixing and spreading unit may move vertically, because of the fact that the wheels I and I operate on the surface being covered which may be rough, but the vertical movement of this unit will have no effect on the finishing unit which carries the strike-off blade. Consequently, there will be no danger of the irregularities of the surface which is to be covered being reflected in the surface produced by the machine.

It will be understood that in some instances it may not be desirable to apply the tack coat. Also, it will be understood that this machine is not limited in its application to the mixing and spreading of bituminous material. It may also be used for mixing in place and spreading various other materials, such as stabilized road materials.

The draw-bar 3| is normally not free to pivot about the point 30. However, if it is desired to turn the machine completely around, the pin 34 may be removed to permit the draw-bar to pivot about point 30. This will permit turning of the entire machine in a short radius. Since the draw-bar 3i normally does not pivot about pin 30 and since the wheel 6 is a caster wheel free to rotate completely about the axis of pin 9, the entire machine may be readily maintained on a straight course. 1

It will be apparent from the above description that I have provided a machine which is adapted to form a road surface from material previously applied in front of the machine on the surface to be treated, either roughly spread across the surface or applied thereto in the form of windrows. The machine will thoroughly mix the material, effectively spread it across the surface to be covered and will form therefrom a layer or slab of the desired thickness and contour and having straight edges, in one pass over said material. Furthermore, with this machine it is possible to apply the tack coat substantially simultaneous with the application of the layer of material thereto. This has a distinct advantage over the prior art method wherein it was necessary to first. apply the tack coat, then apply the crushed stone over the tack coat, the trucks supplying the crushed stone operating over the material will be constricted and win. therefore.

I 2,169,987 a a 1. A-road building machine for operating upon "tack coat" and'the wheels thereof picking'up and removing portions of the tack coat", Furthermore, with the prior art method the tack coat had a chance to set before the crushed stonewas applied thereto and especially before the material was mixed.'

In using this machine, it is possible to employ 'road materials, especially of the bituminous mix type, which will quickly set so as to avoid picking up" by cars whileirafilc is maintained, which is made possible because of the fact that a single pass by the machine over and through the material is all that is necessary to form the completed road surface.

The machine isof such a nature that it is particularly useful in forming low cost roads, since it will form a complete layer or slab with straight edges without the use of expensive side forms that are set along the edges of the surface to be the material.

- sometimes used and when such is the caseseveral passes over the material may be required to thoroughly mix it. If this is the case, I preferably provide an additional element carried by the runner as illustrated in Figures 5 and '6. This element comprisesa wing member 96 which is claim is: I

removably bolted i t'ofthe inner surface of .the. runner at a point behind the strike-off blade. This wing memb'enprojects inwardly and rearwardly and has its lower edge on a level with the lower edge of: the runner One of; these wing' members may be provided for each runner.

1 In using this machine, ordinarily the road is laid in two or'more strips or widths,- After the first'width is laid, when several passes are necessary to mix the material, it isv diiiicult to re-mix the materialthatlies directly adjacent the edge a of the strip already laid. For this reason I provide the member 96 which on the first or subsequent pass over the material will force a portion of the material lying adjacent the edge of the strip already laid inwardly'towards the center of Y the machine and, consequently, it will be more thoroughly mixed. However, on the last pass over the material, the member 96 is entirely removed so that the material will be spread against the adjacent edge of the strip already laid and will be blended therewith.

Although in the specification and claims, I specify that the machine mixes and spreads material previously applied to the surface to'be' treated, it is to be understood that the machine will mix and spread any relatively loose material disposed along the surface to bertreated, whether Having thus described my invention, what I material previously applied to the surface to be treated comprising a mixing and spreading unit, a finishing and molding unit, means for connecting both of said units together in such a manner as to permit them to float relative to each other but to prevent relative lateral movement of said units, said mixing and spreading unitcomprising plow bla es arranged at the forwardend of said unit, a tr nsporting wheel for said mixing and spreading unit disposed behindsaid plow blades so that said blades will clear a path through the material for the wheel, gathering wings disposed at the forward end of said mixing and spreading unit and being laterally spaced from said plow blades, said gathering wings extending rearwardly and inwardly, a mixing box supported on said mixing and spreading unit, said gathering wings being adapted to direct the material into said mixing box, said mixing box being of substantially less width than the width of the layer mixing box for controlling passage of material therethrough, a rudder member disposed at the rear of the mixing box for controlling the amount of material fed to each side of the surface to be covered, a rotatable mixing and spreading member disposed behind said mixing box, saidmember being adapted to spread the material laterally substantially across the surface to be covered, the rear end of said mixing and spreading unit being supported by wheels which operate along paths cleared by said gathering wings, said molding and finishing unit comprising a pair of longitudinally extending runner members of considerabIe'length which are held in spaced parallel relation and which overlap said spreading unit in order to limit lateral spreading of the material, said runners carrying .a. strike-off blade substantially midway between the ends thereof which strikes ofl the material spread by the mixing and spreading unit, said strike-01f blade having ad- 1 justable gates at the ends thereof to permit material to feed back past said strike-off blade, said runners carrying vertically adjustable blender wings which operate upon said matefial.

'2. A road building machine for operating upon material previously applied to the surface to be treated comprising a mixing and spreading unit,

I a finishing and molding unit, means for connecting both of said units together in such a manner as to permit them to float relative to each other butto prevent relative lateral movement of said units, said mixing and spreading unit comprisingplow blades arranged at the forward end of said unit, a transporting wheel for said mixing and spreading unit disposed behind said plow blades so that said blades will clear a path through the material for the wheel, gathering wings disposed at the forward end of said mixing and spreading unit, said gathering wings extending rearwardly and inwardly, a mixing compartmerit supported on said mixing and spreading unit, said gathering wings being adapted to direct the material into said mixing compartment, said mixing compartment being of substantially less width than the width of the layer of material produced by the machine, a plurality of rotatable mixing members disposed in said mixing compartment, means at the rear end of said mixing compartment for governing the amount of material fed to each side of the surface to be covered, a rotatable mixing and spreading member dismolding and finishing unit comprising a pair oi longitudinally'extending runner members of considerable length which are held in spaced relation and which overlap said spreading unit in order to limit lateral spreading of the material. said runners carrying a strike-oil blade substantially midway between the ends thereof which strikes off the material spread by the mixing and spreading unit.'

3. A road building machine ior operatingupon material previously applied to the surface to be treated comprising a mixing and spreading unit, a finishing and molding unit, means for connecting both of said units together in such a manner as to permit them to float relative to each other but to prevent relative lateral movement of said units, said mixing and spreading unit comprising plow blades arranged at the forward end of said unit, gathering wings disposed at the forward end of said mixing and spreading unit, said gathering wings extending rearwardly and inwardly, a mixing compartment carried by said maxing and spreading unit, said gathering wings being adapted to direct the material into said mixing compartment, said mixing compartment being of substantially less width than the width oi the layer of material produced by the machine, a

rotatable mixing member disposed in said mixing compartment, a rotatable mixing and spreading member disposed behind said mixingcompartment, said member being adapted to spread the material laterally substantially across the SUI? face to be covered, said molding and finishing unit comprising a pair of longitudinally extend-,- ing runner members of considerable length which areheld in spaced relation and which overlap said spreading unit in order to limit lateral spreading of the material produced by said unit, said runners carrying a strike-off blade inter, mediate their ends.

4. A road building machine for operating upon material previously applied to the surface to be treated comprising a mixing and spreading unit, a finishing and molding ,unit, means for connecting both of said units together in such a manner as to permit them to float relative to each other but to prevent relative lateral movement of said units, said mixing and spreading unit including a mixing compartment, means for directing the material into said mixing compartment as the machine advances, said mixing compartment being comparatively narrow, a rotatable mixing member disposed in said mixing compartment, a rotatable mixing and spreading member disposed behind said mixing compartment, said member being adapted to spread the material disposed in said mixing compartment, a rotatable mixing and spreading member disposed behind said mixing compartment and adapted to spread the material substantially across the suriace to be covered, said molding and finishing unit comprising a pair of longitudinally extending runner members oi considerable length which are held in spaced relation and which overlap said spreading unit in'order to limit lateral spreading oi material produced by said unit, said runner members carrying a striil'e-oii blade which operates upon the material spread by said mixing and spreading unit.

6. A road building machine for operating upon material previously applied to the surface to be treated comprising a mixing and spreading unit, a finishing and molding unit, means for connecting both 0! said units together in such a. manner as to permit them tofioat relative to each other, said mixing and spreading unit including a pinrality oi rotatable mixing members arranged at longitudinally spaced intervals, said molding and finishing unit comprising a pair oi longitudinally extending runner members of considerable length which are held in spaced relation and are so disposed as to limit spreading of material produced by said mixing and spreading unit, said runner members carrying a strike-off blade which operates upon the material spread by said mixing and spreading unit.

' 7. A road building machine for operating upon material previously applied to the surface to be treated comprising a mixing and spreading unit, a finishing and molding unit, means for connecting both of said units together in such a manner as-to permit them to float relative to each other but to prevent relative lateral movement oi said units, said mixing and spreading unit comprising,

plow blades arranged at theforward end of said unit, a transporting wheel for said mixing and spreading unit disposed behind said plow blades sothat said blades will clear a path through the material for the wheel, means disposed behind said plow blades for applying a coating of bitumen or other suitable material to the surface to be covered along the, path cleared by said plow blades, rearwardly and inwardly extending gathering wings disposed at the iorward end of said mixingand spreading unit and being laterally spaced from said plow blades, said gathering wings being adapted to clear the lateral portions of the surface being covered not cleared by said plow blades of material, means disposed behind said gathering wings for applying a coating oi bitumen or other suitable material to the portions of the surface cleared thereby, a mixing compartment on said mixing and spreading unit being of substantially less width than the width 01 the layer of material produced by the machine, said gathering wings being adapted to direct the material into said mixing compartment, a plurality oi rotatable mixing members disposed in said mixing compartment, a baiile member at the rear of said mixing compartment for controlling passage of material therethrough, means at the rear of the mixing compartment for controlling the amount of material fed laterally to each side of the surface to be covered, a rotatable mixing and spreading member disposed behind said mixing box, said member being adapted to spread the 1 arcane:

runners carrying a strike-off blade which operates upon the material spread by said mixing and spreadin unit.

8. A road building machine for operating upon material previously applied to the surface to be treated comprising a mixing and spreading unit, a finishing and molding unit, means for connecting both of said units together in such a manner as to permit them to float relative to each other, said mixing andspreading unit compris ng plow blades arranged at the forward end of said unit, a transporting wheel for said mixing and spreading unit disposed behind said plow blades so that said blades will clear a path through the material for the wheel, means disposed behind said plow blades for applying a coating of bitumen or other suitable material to the surface to be covered along the path cleared by said plow blades, a second set of blades adapted to clear the lateral portions of the surface being covered not cleared of material by said plow blades, means disposed behind said second set of blades for applying a coating of bitumen or other suitable material to the portions of the surface cleared thereby, said molding and finishing unit comprising a pair of longitudinally extending runner members of considerable length which are so disposed as to limit lateral spreading of material produced by the mixing and spreading unit, said runners carrying a strike-off blade which operates upon the material spread by said mixing and spreading unit.

9. A road building machine for operating upon material previously applied to the surface to be treated comprising a mixing and spreading unit, a finishing and molding unit, means for connecting both of said units together in such a manner as to permit them to float relative to each other but to prevent relative lateral movement of said units, said mixing and spreading unit comprising plow blades arranged at the forward end of sa d unit, a transporting wheel for said mixing and spreading unit disposed behind said plow blades so that said blades will clear a path through the material for the wheel, gathering wings dsposed at the forward end of said mixing and spreading unit and extending rearwardly and inwardly, a mixing compartment supported on said mixing and spreading unit, said gathering wings being adapted to direct the material into said mixing compartment, said mixing compartment being of substantially less width than the width of the layer of material produced by the machine, a plurality of rotatable mixing members disposed in said mixing compartment, means at the rear end of said mixing compartment for governing the amount of material fed to each side of the surface to be covered, a rotatable mixing and spreading member disposed behind said mixing compartment, said member being adapted to spread the material laterally substantially across the surface to be covered, the rear end of said mixing and spreading unit being supported by wheels which operate along paths cleared by said gathering wings, said molding and finishing unit comprising longitudinally extending runner members which are held in laterally spaced relation of material produced by said mixing and spread V 9 and are so disposed as to limit lateral spreading ing unit, and a strike-ofl blade carried by said runner members disposed behind'said' mixing and spreading unit for operating upon material spread thereby.

10. The method of forming a road surface which comprises roughly spreading an'aggregate material over the surface to be covered, applying a binding medium to said material, and then continuously and progressively clearing paths through said aggregate material so as to uncover all portions of said surface and substantially simultaneously applying material to said surface to form a tack coat, constricting the aggregate material and thoroughly mixing it while it'is constricted, and then respreading said material over the portions of said surface to which the tack coat has been applied.

11. The method of forming a road surface which comprises roughly spreading an aggregate material over the surface to be covered, and then continuously and progressively clearing paths through said aggregate material so as to uncover all portions of said surface and substantially simultaneously applying material to. said surface to form a tack coat, constricting the-aggregate material to a width less than that of the surface to be covered and thoroughly mixing it while it is so constricted, and then respreading said material substantially across thersurface to be covered over the tack coat previously applied thereto.

12. The method of forming a road surface from aggregate material in place on the surface to be covered which comprises continuously and progressively clearing paths through said aggregate material so as to uncover all portions of said surface and substantiallysimultaneously applying material to said surface to for a "tack coat, constricting the aggregate material to a width less than that of the surface to be covered and thoroughly mixing it while it is so constricted, and then respreading said material across the surface to be covered over the "tack coat previously applied thereto in a layer of considerably greater width than the width to which said material was constricted.

13. A road building machine for operating upon material disposed along the surface to be treated in front of the machine comprising a runner unit embodying a plurality of laterally spaced longitudinally extending runner members that slide along the surface to be covered and bridge the irregularities thereof, a mixing and spreading unit carried by transporting means, said mixing and spreading unit including a plurality of rotatable mixing members arranged at longitudinally spaced intervals, said runner members being so disposed as to limit spreading of material produced by said mixing and spreading unit, a strike-off blade carried by said runner unit, said strike-off blade being disposed behind said mixing and spreading unit so that it will operate upon material spread by said unit, and means for tying said units together and preventing substantial relative lateral movement, therebetween, said means permitting free vertical movement of the mixing and spreading unit relative to the runner unit so that vertical movement of the mixing and spreading unit caused by the transporting means operating over a rough surface will not be transmitted to said runner unit.

14. A road building machine for operating upon material disposed along the surface to be treated in front of the machine comprising a runner unit embodying a plurality of laterally spaced longitudinally extending runner members that slide along the surface to be covered and bridge the irregularities thereof, a mixing and spreading unit carried by transporting means, said mixing and spreading unit including a mixing compartment, said mixing compartment being ,l of less width than the layer of material adapted to be produced by the machine, means for guiding the material into said compartment as the machine advances, a rotatable mixing member disposed in said mixing compartment, means for spreading said material laterally to a greater width than the compartment as it leaves said mixing compartment, said runner members being so disposed as to limit spreading of material produced by said spreading means, a strike-off blade carried by said runner unit, said strike-oil blade being disposed behind said means for spreading the material laterally so that it will operate upon said material, and means for tying said units together and preventing substantial relative lateral movement therebetween, said means permitting free vertical movement of the mixing and spreading unit relative to the runner unit so that vertical movement of the mixing and spreading unit caused by the transporting means operating over a rough surface will not be transmitted to said runner unit.

15. A road building machine for operating upon material disposed along the surface to be treated in front of the machine comprising a runner unit embodying a plurality of laterally spaced longitudinally extending runner members that slide along the surface to be covered and bridge the irregularities thereof, a mixing and spreading unit carried by transporting means, said mixing and spreading unit including a longitudinally extending mixing compartment having a rotatable mixing member disposed therein, said runner members overlapping said mixing and spreading unit in order to limit lateral spreading of material produced by said unit, a strike-oil blade carried by said runner unit and disposed so that it will operate upon material spread by said mixing and spreading unit, and means for tying said units together in such a manner as to permit free vertical movement of the mixing and spreading unit relative to the runner unit so that vertical movement of the mixing and spreading unit caused by the transporting means operating over a rough surface will not be transmitted to said runner unit.

16. A road building machine for operating upon material previously applied to the surface to be treated comprising a runner unit embodying a plurality of laterally spaced longitudinally extending runner members that slide along the surface to be covered and bridge the irregularities thereof, a mixing and spreading unit carried by transporting means, said mixing and spreading unit including a mixing compartment having a rotatable mixing member disposed therein, means for directing the material into the mixing compartment as the machine advances there'through, said runner members overlapping said mixing and spreading unit in order to limit lateral spreading of the material produced by said unit, a strike-off blade carried by said runner unit and disposed so that it will operate upon material spread by said mixing and spreading unit, and means for tying said units together in such a manner as to permit free vertical movement of the mixing and spreading unit relative to the runner unit so that vertical movement of the mixing and spreading unit caused by the transporting means operating over a rough surface will not be transmitted to said runner unit.

17. A road building machine for operating upon material disposed along the surface to be treated in front of the machine comprising a runner unit embodying a plurality of laterally spaced longitudinally extending runner members that slide along the surface to be covered and bridge the irregularities thereof, a mixing and spreading unit carried by transporting means, said mixing and spreading unit including a mixing compartment, said mixing compartment being of less width than the layer of material adapted to be produced by the machine, means in said compartment for mixing said material, means for spreading said material laterally to a greater width than the compartment as it leaves said mixing compartment, said runner members being so disposed as to limit spreading of material produced by said spreading means, a strike-off blade carried by said runner unit, said strike-off blade being disposed behind said means for spreading the material laterally so that it will operate upon said material, and means for tying said units together and preventing substantial relative lateral movement therebetween, said means permitting free vertical movement of the mixing and spreading unit relative to the runner unit so that vertical movement of the mixing and spreading imit caused by the transporting means operating over a rough surface will not be transmitted to said runner unit.

18. A road building machine for operating upon material previously applied to the surface to be treated comprising a runner unit embodying a plurality of laterally spaced longitudinally extending runner members that slide along the surface to be covered and bridge the irregularities thereof, a spreading unit supported on a plurality of transporting members, blade members disposed in front of all of said members for clearing paths through said material so that all of said members will operate upon the surface to be covered, a strike-off blade carried by said runner unit for levelling off material spread by said spreading unit, and means for tying said units together in such a manner as to permit free vertical movement of the spreading unit relative to the runner unit so that vertical movement of the spreading unit caused by the transporting members operating over a rough surface will not be transmitted to said runner unit.

19. A road building machine for operating upon material previously applied to the surface to be treated comprising a runner unit embodying a plurality of laterally spaced longitudinally extending runner members that slide along the surface to be covered and bridge the irregularities thereof, a mixing and spreading unit carried bytransporting means, said mixing and spreading unit including a mixing compartment, a rotatable mixing member disposed in said mixing compartment, means behind said mixing compartment for spreading material substantially across the surface to be covered, said runner members being so disposed as to limit lateral spreading of material produced by said spreading means disposed behind said compartment, a strike-off blade carried by said runner unit for operating upon the material spread by said mixing and spreading unit, and means for tying said units together in such a. manner as to permit free (iii ' produced by the machine, means for spreading verticalmovement of the mixing and spreading unit relative to the runner unit so that vertical -movement of the mixing and spreading unit caused by the transporting means operating over a rough surface will not be transmitted to said runner unit.

20. A road building machine for operating upon material disposed along the surface to be treated in front of the machine comprising a runner unit embodying a plurality of laterally spaced longitudinally extending runner members Q'that slide along the surface to be covered and ,bridge the irregularities thereof, a mixing and spreading unit carried by transporting means,

said mixing and spreading unit including a mixing compartment, said mixing compartment being of .less width than the layer of material adapted to be'produced by the machine, a rotatable mixing member disposed in said mixing compartment, a rotatable mixing and spreading member disposed behind said mixing compartment and-adapted to spread the material laterally acrossthe surface to be covered in a layer of considerably'greater width than the width of said mixing compartment, said runner members being so disposed as to limit lateral spreading of material produced by said rotatable mixing and spreading member, a strike-off blade carried by said runner unitfor levelling on material spread by said rotatable mixing and spreading member, and means for tying said units together and pre venting substantial relative lateral movement therebetween,said means permitting free vertical movement of the mixing and spreading unit relative to the runner unit so that vertical movement of the mixing and spreading unit caused A by the transporting means operating over a rough surface will not be transmitted to said runner unit.

21. A road building machine for operating upon material previously applied to the surface to be treated comprising a runner unit embodying a plurality of laterally spaced longitudinally extending runner members that slide along the surface to be covered and bridge the irregularities thereof, a mixing and spreading unit carried by transporting means, said mixing and spreading unit including a mixing compartment, means for directing material into said mixing compartment as the machine advances through the material, said mixing compartment being of less width than the layer of material adapted to be said material laterally across the surface to be covered after it leaves said mixing compartment in a layer of considerably greater width than the width of said mixing compartment, said runner members being so disposed as to limit lateral spreading of material produced by said spreading means, a strike-off blade carried by said runner unit for levelling on material spread by said spreading means, and means for 10 tying said units together and preventing substantial relative lateral movement therebetween, said means permitting free vertical movement of the mixing and spreading unit relative to the runner unit so that vertical movement of the mixing and spreading unit caused by the transporting means operating over a rough surface will not be transmitted to said runner unit.

22. A road building machine comprising a runner unit embodying a pair of laterally spaced longitudinally extending runner members that slide along the surface to be covered and bridge the irregularities thereof, a second unit carried by transporting means, a strike-off member carried by said runner unit, means disposed at a point behind said strike-off member for directing material inwardly towards the center of the machine, and means for tying said units together in such a manner as to permit free vertical movement of the second unit relative to the runner unit so that vertical movement of the second unit caused by the transporting means operating over a rough surface will not be transmitted to said runner unit.

23. A road building machine comprising a runner unit embodying a pair of laterally spaced longitudinally extending runner members that slide along the surface to be covered and bridge the irregularities thereof, a second unit carried by transporting means, a strike-off member carried by said runner unit, means carried by one of said runners at a point behind said strike-off member for directing material inwardly from said runner, and means for tying said units together in such a manner as to permit free vertical movement of the second unit relative to the runner unit so that vertical movement of the second unit caused by the transporting means operating over a rough surface will not be transmitted to said runner unit.

JOSEPH H. MOSEL.

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