Automated Paving Machine

Abstract

A compact self-propelled paving machine whose hopper, for receiving asphalt or other paving material therein, discharges the paving material rearwardly of the supporting drive wheels of the machine and directly upon the surface to be paved. The drive wheels, as well as motive means and drive mechanism connecting the motive means to the drive wheels, are so compactly arranged that the hopper substantially entirely overlies the same. Such compact construction facilitates positioning a standard size dump truck, or a larger so-called tandem-wheel dump truck, in such close proximity to the hopper that the paving material can be dumped directly from the truck bed into the hopper and discharged from the lower portion of the same hopper directly upon the surface to be paved, thereby obviating the need for intervening conveyor means for transferring the dumped paving material to the point at which it is discharged onto the surface to be paved. The machine also includes distributing augers, discharge gate means, a vertically movable screed and extensible and retractable screed extensions, all of which, in addition to the drive mechanism for the drive wheels, are automatically controlled by an operator at a convenient centralized location on the machine during the paving operation.

Description

BRIEF SUMMARY OF THE INVENTION

Some paving machines or spreaders which are of the type attached to and propelled by a truck or other vehicle during paving operations, are so constructed that the rear portion of a truck bed may overlie the hopper of the paving machine to facilitate dumping or otherwise transferring the paving material from the truck bed directly into the hopper and onto the usual distributing auger means thereof adjacent the discharge opening of the hopper through which the paving material is discharged directly upon the surface to be paved. Various forms of self-propelled paving machines also have been proposed heretofore having hoppers from which paving material is discharged onto a surface to be paved during the paving operation. However, in such proposed self-propelled paving machines, following the transfer or dumping of the paving material from a truck onto the paving machine, various encumbrances, such as drive motors, control mechanisms and driving connections from the motors to the drive wheels, augers and other operating components of the self-propelled paving machine, have required that further handling or conveyance of the transferred paving material had to be effected in order to deliver the paving material to the point at which the paving material is discharged from the paving machine onto the surface to be paved. Generally such further conveyance or handling of the previously transferred paving material has been effected by means of a conveyor belt or belts extending from a front end hopper of the paving machine to a rear end hopper or other means for discharging the paving material onto the surface to be paved. It has also been proposed to utilize a tiltable or otherwise movable skip, large bucket or other container positioned adjacent the front end of a paving machine for receiving paving material therein from a truck, and wherein such skip, large bucket or container is operated by a hoist or the like for subsequently transferring the paving material rearwardly into a hopper having a discharge opening in its lower portion for discharging the paving material received therein onto the surface to be paved.

It is an important object of this invention to provide an improved, self-propelled paving machine or spreader which is compact, highly efficient and self-contained and eliminates the aforementioned and other disadvantages of self-propelled paving machines proposed heretofore.

It is another object of this invention to provide a self-propelled paving machine having two substantially axially aligned sets of drive wheels supporting the same for movement over the surface to be paved and disposed beneath the hopper thereof, which sets of wheels are motor-driven and are manually controllable independently of each other to not only facilitate steering the paving machine, but to also facilitate turning the entire machine about a substantially centrally disposed vertical axis located about midway between the two sets of drive wheels.

Still another object of this invention is to provide a self-propelled paving machine having motor-driven distributing augers in the opposing side portions of the hopper thereof and which are manually controllable independently of each other, and wherein, upon the torque load on one auger becoming substantially greater than that on the other auger, the speed of the other auger automatically increases relative to that of said one auger. Also, the other auger will continue to rotate even though the torque load on said one auger may be such as to stop the rotation thereof.

It is another object of this invention to provide an improved self-propelled paving machine having a vertically movable screed on the rear portion thereof with power means for raising and lowering the screed, which power means is manually controllable by an operator regardless of whether or not the machine is in the performance of a paving operation.

Still another object of this invention is to provide a paving machine having a main screed on the rear portion thereof which is provided with telescoping screed extensions and associated sled members, and which includes power means for adjustably extending and retracting the screed extensions relative to the main screed. The power means is manually controllable so that either or both screed extensions and associated sled members thereof may be adjusted relative to the main screed, even during the performance of a paving operation.

BRIEF DESCRIPTION OF THE DRAWINGS

Some of the objects and advantages of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings in which--

FIGS. 1 and 2 are respective front and rear perspective views of a preferred embodiment of the paving machine of this invention;

FIG. 3 is an enlarged left-hand side elevation of the paving machine looking at the lower left-hand side of FIG. 2 and showing the same in association with the rear lower portion of a standard size dump truck;

FIG. 4 is a top plan view of the paving machine;

FIG. 5 is an enlarged plan view similar to FIG. 4, but wherein the hopper lower wall means has been removed to expose the drive wheels, the motive means, connections between the motive means and the drive wheels, the various other parts of the paving machine over which the lower wall means normally extends;

FIG. 6 is a vertical sectional view taken substantially along line 6--6 in FIG. 5, but including the hopper lower wall means and showing the truck bed receptor thereof occupying a normally lowered position preparatory to reception of the lower rear portion or chassis of a truck therein, as in FIG. 3;

FIG. 7 is a view similar to FIG. 6, but wherein the receptor occupies fully raised position for dumping any paving material which may have accumulated thereon onto the inclined bottom wall panel of the hopper lower wall means;

FIG. 8 is another view similar to FIG. 6, but is taken substantially along line 8--8 in FIG. 5 and shows the entire lower wall means of the hopper occupying a raised position to permit ready access to the motive means, drive wheels and various drive mechanisms normally located beneath the lower wall means;

FIG. 9 is an enlarged, partially exploded and partially sectioned perspective view of the right-hand portion of the screed means shown in FIG. 2 and particularly illustrating the related screed extension and sled member;

FIG. 10 is an enlarged fragmentary vertical sectional view taken substantially along line 10--10 in FIG. 5 particularly illustrating clutch means for selectively engaging and disengaging a respective set of drive wheels relative to the corresponding drive mechanism;

FIG. 11 is a fragmentary sectional plan view taken substantially along line 11--11 in FIG. 10, showing the clutch means for both sets of drive wheels;

FIG. 12 is a fragmentary elevation, partially in section, taken substantially along line 12--12 in FIG. 11;

FIG. 13 is an enlarged fragmentary vertical sectional view taken substantially along line 13--13 in FIG. 11;

FIG. 14 is an enlarged, exploded, perspective view of the hopper and main frame disassociated from the remainder of the paving machine;

FIG. 15 is a schematic diagram of fluid pressure circuits for the paving machine;

FIG. 16 is a view similar to FIG. 6 showing a modified form of the paving machine;

FIG. 17 is a fragmentary view looking up, along line 17--17 in FIG. 16, at the modified means for raising and lowering the truck bed receptor; and

FIG. 18 is a fragmentary view of modified drive means for the augers, and taken substantially along line 18--18 in FIG. 16.

DETAILED DESCRIPTION

MAIN FRAME

Referring more specifically to the drawings, the numeral 20 broadly designates a main frame supported for movement over the ground or a surface to be paved by means of right-hand and left-hand sets of drive wheels 21, 21a and a front support means, in the form of a swivelling pair of wheels or casters 23. A hopper 24 is supported by frame 20, and screed means 25 is positioned adjacent the rear portion of hopper 24 for smoothing and compacting paving material being discharged from hopper 24 as the paving machine moves forwardly over the surface to be paved.

As best shown in FIGS. 1, 5 and 14, main frame 20 comprises an elongate main or front end frame member 20a which is about the same length as the corresponding length of the hopper 24 measured transversely of the normal direction of travel of the paving machine. The front ends of a plurality of spaced apart bridging frame members 20b are connected to front frame member 20a and their rear portions are connected to an intermediate frame member 20c spaced rearwardly from and extending substantially parallel with main frame member 20a. The forward portions of right-hand and left-hand sets of wheel-mounting frame members 20d, 20d' are suitable secured to frame member 20c, and a relatively larger rearwardly extending middle frame member 20e is connected at its front end to a medial portion of frame member 20c. A relatively small platform 20f is suitably secured upon the middle frame member 20e and the two adjacent wheel-mounting frame members 20d, 20d' straddling the same.

The sets of drive wheels 21, 21a are keyed or otherwise suitably secured on respective axles or shafts 26, 26a journaled in respective sets of bearings 27 (FIG. 8) and 27a (FIG. 3) suitably secured to the lower surfaces of the respective sets of frame members 20d, 20d' (FIGS. 5, 8 and 14).

DRIVE MECHANISM FOR DRIVE WHEELS

A motive means, which may take the form of an internal combustion engine 30, is suitably secured on a front right-hand corner portion of main frame 20 immediately rearwardly of front frame member 20a (FIGS. 1 and 5) and is operatively connected to drive wheels 21, 21a through a drive mechanism including a composite fluid pressure pump means 31 to which the drive shaft of motor 30 is drivingly connected. Referring to FIG. 15, it will be observed that pump means 31 includes two pump units 31a, 31b which are components of respective first and second fluid pressure circuits, but whose inlets are connected to a common source of fluid in an L-shaped reservoir or tank 32 suitably secured on a left-hand front corner portion of main frame 20 immediately rearwardly of front frame members 20a (FIGS 1, 2, 5, 8 and 15).

A conduit means 33 connects the outlet of pump unit 31a to a high pressure manifold 34 having branches 34a, 34a' extending therefrom to respective manually operable, four-way, control valves 35, 35a, with built-in bypasses and each having respective sets of outlet conduits a, b, c extending therefrom. Control valves 35, 35a may be of a well-known type, such as Model "CP" valves as manufactured by Gresen Hydraulics, Minneapolis, Minn., for example. Pump means 31 may be of a type known as a Model DCB-6-4.5 as manufactured by said Gresen Hydraulics, for example.

Conduits a, b of valves 35, 35a are connected to opposite sides of respective reversible fluid-operated motors 36, 36a drivingly connected to the respective sets of drive wheels 21, 21a. A torque limiting means is common to both sets of drive wheels 21, 21a so that they normally will rotate in the same direction (either forwardly or rearwardly) at the same speed. To this end, the output shafts of the fluid-operated motors 36, 36a are substantially axially aligned, extend toward each other, and are coupled together by means of a torque limiter 40, which may be of any desired or conventional construction, to normally cause the shafts of both motors 36, 36a to rotate in fixed relationship, but which permits either motor shaft to override and rotate relative to or independently of the other motor shaft upon the torque load on either shaft becoming substantially and predeterminedly greater than that on the other shaft. This may occur, for example, upon obstruction of rotation of one set of drive wheels only, as in the event of one set of drive wheels engaging a large rock or other obstruction in its path, and the other set of drive wheels not being obstructed. This will also occur upon one set of drive wheels being subjected to a predetermined greater driving force than the other set of drive wheels or the one set being driven in the opposite direction from the other set through manual manipulation of control valves 35, 35a.

The torque limiter is desirable because the response of the two motors 36, 36a to a given or like amount of fluid pressure may not be the same, or a relatively small variation in the torque load on either motor relative to the other might otherwise cause one set of the drive wheels 21, 21a to rotate faster than the other set and thereby turn the paving machine away from its intended path, unless the operator made frequent exacting compensating changes in the state of control valves 35, 35a. Obviously, the need for such frequent and exacting manual operation of the control valves would be arduous and might divert the operator's needed attention from the performance of other tasks.

In an actual machine constructed according to this invention, the fluid-operated wheel drive motors were of a type manufactured by said Gresen Hydraulics under their Model No. 1016 and each motor 36, 36a had an output rating of about 150 foot-pounds torque. A torque limiter 40 of a type manufactured by Morse Chain Company, Ithaca, N.Y., under their Model No. 350A-1 was utilized and was adjusted to interrupt the fixed relationship between the shafts of motors 36, 36a upon occurrence of a torque differential therebetween of about 30 foot-pounds.

Conduits c extend from valves 35, 35a to an exhaust manifold 38 connected by a conduit 39 to reservoir 32 to return the fluid being pumped by unit 31a to reservoir 32 when the wheels 21, 21a are not being driven.

To drivingly connect fluid-operated motors 36, 36a to the respective drive wheel shafts 26, 26a, the drive shaft of each motor 36, 36a has a sprocket wheel 37 fixed thereon (FIGS. 5 and 10) and engaged by an endless sprocket chain 37a. Chain 37a extends forwardly and engages a relatively larger sprocket wheel 37b. Each of the two sprocket wheels 37b is mounted on a respective jack shaft 37c journaled on adjacent bridging frame members 20b and is in fixed axial relation to a relatively smaller sprocket wheel 37d. An endless sprocket chain 37e engages each sprocket wheel 37d, extends rearwardly therefrom and is mounted on a relatively larger sprocket wheel 37f.

Each sprocket wheel 37f is suitably secured to one end of a hub or sleeve 42a of a corresponding clutch mechanism broadly designated at 42 (FIG. 13). Sprocket wheel 37f and its hub 42a are rotatably mounted on a bushing 37g rotatably mounted on the respective drive wheel shaft or axle 26, 26a. Hub 42a is of square or polygonal exterior cross-sectional configuration and matingly receives thereon a clutch slide 42b which is shiftable between the engaged solid-line and disengaged broken-line positions of FIG. 13. Thus, slide 42b rotates with hub 42a and sprocket 37f whenever they are being driven by the corresponding motor 36 or 36a.

It should be noted that the proximal ends of axles 26, 26a are spaced apart from each other, and the inner end of each axle 26, 26a has a clutch block 42c positioned thereagainst and welded or otherwise suitable secured thereto. The size and configuration of the periphery of each clutch block 42c corresponds substantially to that of the corresponding hub 42a so that, when the clutch slide 42b occupies its innermost position, remote from the corresponding sprocket wheel 37f, the clutch slide 42b bridges, and establishes a driving connection between, the hub 42a of sprocket wheel 37f and clutch block 42c to drive the corresponding axle 26 or 26a, as the case may be.

In order to shift each clutch slide 42b between the engaged and disengaged positions shown in respective solid and broken lines in FIG. 13, each clutch slide 42b is provided with a peripheral groove 42d therein which is engaged by a pair of substantially diametrically opposed followers on the arms of a corresponding yoke 42f. As best shown in FIGS. 11 and 12, the two yokes 42f are mounted for lateral sliding movement, parallel to the axis of axles 26, 26a, on a bar 42g whose opposite ends are suitably secured to blocks 42h projecting rearwardly from frame member 20c. A bifurcated portion 42i of each yoke 42f is engaged by a radially extending finger 42j on the rear end of a corresponding shipper shaft 42k.

The shipper shafts 42k are journaled in and extend through frame members 20a, 20c, and the forward ends thereof are provided with suitable respective shipped hand cranks 42m positioned adjacent the front surface of front frame member 20a so as to be readily accessible for shifting each of the clutches 42.

During self-propulsion of the paving machine, as during movement thereof relatively short distances of, say up to one mile, between paving sites, and during paving operations, both clutches 42 occupy operative positions, with the respective clutch slides 42b thereof occupying the solid-line position of FIG. 13 and as shown in FIGS. 11 and 12. However, when the paving machine is to be moved substantial distances, such as several miles from one paving site to another, both clutch slides 42b may be manually moved to the inoperative position to permit free-wheeling of the drive wheels 21, 21a by a truck or other pulling vehicle. Such free-wheeling of the drive wheels relieves the entire drive mechanism from any load thereon during travel of the paving machine from one location to another and thereby avoids unnecessary wear of the drive mechanism, since the axles 26, 26a then may rotate without imparting rotation to the corresponding sprocket wheels 37f.

To further facilitate moving the paving machine substantial distances while clutches 42 are disengaged, a bracket 23a, to which the caster wheels 23 (FIGS. 1, 3, 6, 7 and 8) are connected for steering movement about a substantially vertical axis, is suitably secured to and extends forwardly from front frame member 20a and has a forwardly and rearwardly extending tubular draft-bar-receiving coupler 23b fixed on a forward portion thereof. A conventional draft bar, not shown, and connected to the rear end of a truck or other vehicle, thus may be inserted in the forward portion of coupler 23b and held therein by means of a pin or bolt extending through an opening 23c through coupler 23b to facilitate pulling the paving machine substantial distances. Of course, the draft bar may be removed from the coupler 23b when the paving machine is being moved from place to place under its own power and during paving operations.

HOPPER CONSTRUCTION

The compact arrangement of frame 20, drive wheels 26, 26a, main drive motor 30, reservoir 32 and the drive mechanism between motor 30 and drive wheels 26, 26a facilitates so constructing hopper 24 that it substantially completely overlies the frame, drive wheels, main drive motor, reservoir and the drive mechanism between motor 30 and drive wheels 26, 26a, with the paving material being discharged from the hopper 24 closely adjacent and rearwardly of drive wheels 26, 26a directly onto the surface to be paved.

As best shown in FIGS. 1-4, 6-8 and 14, hopper 24 comprises substantially upright rear end wall means 24a, spaced side wall means 24b, 24c, and a lower wall means broadly designated at 44 and defining the bottom of hopper 24. The rear edges of side wall means 24b, 24c are welded or otherwise suitably secured to opposing side edges of rear end wall means 24a, and the lower portions of side wall means 24b, 24c, are suitably secured to the outer surfaces of the distal frame members 20d, 20d'. Since paving machines are usually constructed to conveniently lay a paved strip about 8 feet wide, the side wall means 24b, 24c may be spaced about 8 feet apart from each other. The hopper 24 may be about 4 feet wide, for example, measured from the front surface of front frame member 20a to the rear surface of rear end wall means 24a. In order to enlarge upon the capacity of hopper 24 and/or to facilitate positioning the rear portion of an usually wide truck bed between the upper portions of the side wall means 24b, 24c, movable auxilary side wall panels 24b', 24c' may be pivotally connected to upper portions of side wall means 24b, 24c, respectively, for adjustment about substantially horizontal axes. The rear portions of panels 24b', 24c' are provided with arcuate plates 45 extending inwardly therefrom and engaged by respective hook members or fasteners 46 mounted for longitudinal adjustment in tubular members 47 carried by the rear upper portions of side wall means 24b, 24c. The rear ends of hook members 46 have internally threaded cranks 50 threaded thereon. Cranks 50 are adapted to be rotated by the operator to tighten and loosen the corresponding hook members 46 relative to the arcuate plates 45 to facilitate adjusting the auxilary side wall members 24b', 24c' inwardly and outwardly relative to the side wall means 24b, 24c.

When hopper 24 is substantially filled with paving material, it is preferred that the center of gravity of the entire paving machine is located adjacent to and forwardly of the drive wheel axles 26, 26a. Therefore, to insure that an excess amount of paving material is not disposed rearwardly of the desired center of gravity, it is preferred that the rear end wall means is inclined upwardly and forwardly at a shallow angle relative to the vertical of about 5.degree. to 10.degree.. The lower portion of rear end wall means 24a has a downwardly and forwardly inclined bib portion 24a' thereon which partially underlies auger means to be later described.

The lower wall means 44 includes a downwardly and rearwardly inclined bottom wall panel 54. In the first embodiment of FIGS. 1-15, opposite side portions of panel 54 are removably secured to side wall means 24b, 24c by means of screws 55. The inclined bottom wall panel 54 extends over drive wheels 21, 21a with its lower edge spaced forwardly from the rear end wall means 24a to define an elongate discharge opening 56 therebetween through which paving material is discharged from hopper 24 to fall onto the surface to be paved. Opposing side areas of discharge opening 56 are selectively opened and closed by gate means including right-hand and left-hand substantially aligned, discharge gates 57, 57a. The rear lower edge of inclined bottom wall panel 54 and the upper forward edges of gates 57, 57a are pivotally mounted on a pivot shaft 60 (FIG. 8) extending through the rear portions of the wheel-mounting frame members 20d, 20d' (FIG. 14).

The discharge gates 57, 57a are power-operated but individually controlled by an operator so that, if desired, one of the gates may be closed while the other is opened to discharge paving material from only about one-half of the width of the hopper 24. Also, discharge gates 57, 57a may be opened during paving of a desired surface and, while the hopper still contains a supply of paving material, the gates may be closed and the machine may be moved to another location, or for a relatively short distance, as desired, before again commencing the depositing of paving material onto the surface therebeneath. To this end, a separate power means including a fluid-operated gate ram 62, is connected to each discharge gate exteriorly of the hopper.

As shown in FIG. 8, fluid-operated ram 62 is in the form of a cylinder over which lower wall means 44 normally extends and which contains a suitable piston, not shown, to which a piston rod 65 is connected. The piston rod 65 is pivotally connected, as at 66, to a lower rear portion of the corresponding gate 57 or 57a, as the case may be, and the cylinder of ram 62 is pivotally connected at its front portion, as at 67, to frame member 20c. The two cylinders 62 are of the double-acting type and are controlled by respective manually operable, four-way control valves 70, 70a (FIG. 15) whose inlet conduits 71, 71a are connected to a high pressure manifold 72. Manifold 72 is connected to the output end of a conduit 73, whose input end is connected to the outlet of pump unit 31b. A manually operable switching valve 31c is connected across conduits 33, 73 for purposes to be later described.

The control valves 70, 70a are manually controlled so as to selectively direct fluid, under pressure, although corresponding conduits d, e f, connected thereto. The other ends of conduits d, e, are connected to opposite ends of the corresponding right-hand and left-hand cylinders 62. The conduits f extend from control valves 70, 70a to a common exhaust or fluid returning, low pressure, manifold 75 connected, by means of a conduit 76, to the upper portion of reservoir 32.

The upper front extremity of inclined bottom panel 54 of lower wall means 44 terminates along a line spaced rearwardly from the vertical plane of front frame member 20a and has a pair of spaced apart shelves 54b, 54b' (FIGS. 1, 2 and 14), preferably formed integral therewith, extending forwardly therefrom and overlying the enlarged or higher outer portion of L-shaped reservoir 32 and motor 30, respectively. The front end portions of shelves 54b, 54b' have respective pairs of legs 54c, 54c' secured thereto and depending therefrom, and which normally rest upon front frame member 20a. Thus, the proximal edges of shelves 54b, 54b' define a recess therebetween, opposed sides of which are closed by closure plates 54d, 54d' welded or otherwise suitably secured to the proximal edges of shelves 54b, 54b' and the corresponding legs 54c, 54c' .

To accommodate the rear portion of a standard dump truck, whose bed may be relatively low and relatively narrow, for depositing the paving material in hopper 24, a substantially L-shaped receptor 54e normally fits loosely between closure plates 54d, 54d' and has the upper edge of its rear panel portion hingedly or pivotally connected to the exposed front upper edge of a medial portion of inclined bottom panel 54. Since the front edge of the bottom panel of receptor 54e is of relatively thin sheet metal, the front edge thereof may be reinforced by a reinforcing bar or lip 54f.

Receptor 54e serves to collect therein any paving material which spills off the truck bed positioned thereover without being deposited on the inclined bottom wall 54 and, after the truck has withdrawn from the paving machine, receptor 54e may be pivoted upwardly and rearwardly to the position shown in FIG. 7 so that the contents thereof may slide out of the receptor and onto the inclined bottom panel 54. Additionally, the reinforcing bar 54f on the front edge of the bottom panel of receptor 54e serves to restrain either a standard size dump truck or a tandem wheel dump truck from accidentally moving away from the paving machine during the transfer of paving material from a truck bed into hopper 24 and while the paving machine is being moved over and depositing paving material on the surface being paved. In this regard, it will be noted that front end frame member 20a is provided with a pair of spaced apart, substantially axially aligned and elongate rollers 80, 80' thereon which are adapted to engage the rear wheels of a truck T as shown in FIG. 3 so that the paving machine pushes the truck along the surface to be paved during the transfer of paving material therefrom into hopper 24 and during the paving operation.

The lower surface of receptor 54e normally rests on a pair of posts 54g on frame member 20a. In order to raise and lower receptor 54e between the positions shown in FIGS. 6 and 7, and to also raise the receptor 54e from its normal lowered position of FIG. 6 to a position where its reinforcing bar 54f will engage a lower portion of the truck bed or its rear springs forwardly of the rear spring shackles thereof, in the first embodiment the lower surface of the bottom panel of receptor 54e normally engages a cam plate 81 secured on or formed integral with a receptor actuator arm 82. Arm 82 normally extends downwardly and forwardly and is pivotally connected, as at 83, to bracket 23a (FIGS. 6 and 7). Adjacent its free end, a piston rod 84 of a double-acting receptor ram or cylinder 85 is pivotally connected to actuator arm 82. Piston rod 84 is connected to a piston within cylinder 85, and the end of cylinder 85 remote from actuator arm 82 is pivotally connected as at 86, to a lower front portion of frame member 20c. Thus, lower wall means 44 normally extends over cylinder 85.

Receptor 54e is controlled by a manually operable control valve 87, which may be of the same type as valves 35, 35a, and whose inlet is connected to high pressure manifold 72 by means of a branch conduit 87a (FIG. 15). Conduits g, h, i, into which fluid is directed in a selective manner by the operator, lead from control valve 87a. Conduits g, h, are connected to opposite ends of cylinder 85, and conduit i is connected to low pressure manifold 75.

When control valve 87 is manipulated by the operator to introduce fluid pressure into the lower or rear portion of cylinder 85, piston rod 84 moves actuator arm 82 upwardly and forwardly the desired distance so as to either cause reinforcing bar 54f to engage the lower portion of a truck bed in the manner heretofore described, or to cause actuator arm 82 to move to its full forward position shown in FIG. 7. When piston rod 84 is being fully extended, the actuator cam 81 moves receptor 54e upwardly a predetermined distance, whereupon it tightens a normally slack pliable element or chain 90 removably connected to and extending between actuator arm 82 and an arm 91 secured to and extending rearwardly from the substantially vertical panel of receptor 54e when receptor 54e occupies its normal fully lowered position.

Such tightening of chain 90, and the consequent forward pull imparted to chain 90 by actuator arm 82 swings receptor 54e upwardly and away from cam 81 until the former rear panel thereof is substantially aligned with the inclined bottom panel 54 as shown in FIG. 7. As receptor 54e reaches the fully raised position of FIG. 7, a leaf spring member 92, secured to the rear panel thereof, engages and is biased by the upper surface of inclined bottom panel 54. The leaf spring member 92 thus provides means for initiating the return of receptor 54e from the fully raised position toward the lowered position when the flow of fluid pressure into cylinder 85 is reversed and consequent slackening of chain 90 occurs. Thus, with further retraction of piston rod 84 into cylinder 85, receptor 54e falls onto cam 81 and thus may return to fully lowered position with cam 81 and actuator arm 82. Whenever lower wall means 44 is to be raised to the position of FIG. 8, it is apparent that bolts 55 (FIGS. 1 and 2) may be removed from side wall means 24b, 24c, and chain 90 is detached from actuator arm 82.

ROTARY AUGER MEANS

A rotary auger means is provided in the lower rear portion of hopper 24, above and adjacent discharge opening 56, to aid in uniformly distributing the paving material from side to side in hopper 24 when desired. More importantly, the auger means facilitates feeding paving material to screed extensions to be later described. The rotary auger means comprises right-hand and left-hand distributing augers 100, 100a whose proximal end portions are journaled in suitable bearings carried by middle frame members 20e in the first embodiment of the paving machine. The outer end portions of the augers 100, 100a, adjacent the respective side wall means 24b, 24c of hopper 24, are journaled in respective bearing brackets 103, 103a (FIG. 5) which extend upwardly from the shafts of augers 100, 100a and are welded or otherwise suitably secured to side wall means 24b, 24c. The proximal portions of the shafts of augers 100, 100a, and frame member 20e, are positioned within a housing 104 normally closed by a substantially L-shaped cover 104' which serves normally as part of lower wall means 44 and whose opposing end portions are removably secured, as by screws 104a, to the rear end wall means 24a and the inclined bottom panel 54, respectively, of hopper 24. Cover 104' is removed from housing 104 whenever lower wall means 44 is to be raised to the position of FIG. 8. Within housing 104, the shafts of augers 100, 100a are engaged by respective sprocket wheels j, k (FIG. 5) on which respective endless sprocket chains l, m are mounted as best shown in FIGS. 5, 6 and 7. Sprocket chains l, m extend forwardly through a suitable opening provided in the lower portion of bottom wall panel 54 and are mounted on respective sprocket wheels n, o, driven by respective fluid-operated auger motors 105, 105a. The auger motors are mounted on platform 20f in the first embodiment (FIGS. 5 and 14).

Fluid-operated motors 105, 105a are reversible and are controlled by respective manually operable control valves 106, 106a (FIG. 15), each of which has a plurality of conduits p, q, r, connected thereto and leading therefrom. Conduits p are connected to manifold 72 and conduits s are connected to manifold 75. Conduits q, r of valves 106, 106a are connected to opposite sides of the respective auger motors 105, 105a. Valves 106, 106a may be of the same type as those manually controlled valves heretofore described and may be manually manipulated to drive augers 100, 100a at the desired speed and in the desired direction independently of each other. The auger motors 105, 105a may be of a type manufactured by Char-lynn Company, Eden Prairie, Minn. under Model No. 18S having a torque rating of about 200 foot-pounds.

Referring to FIG. 15, since pump unit 32b provides fluid pressure for operating both auger drive motors 105, 105a through the respective control valves 106, 106a, there is incorporated in the auger drive a self-equalizing principle to the extent that, the greater the torque load on one auger relative to that on the other auger, the greater is the differential speed therebetween. This occurs because a greater amount of fluid will flow, per unit of time, through that motor whose auger is under a relatively light torque load than that which will flow through the other auger motor whose auger is under a relatively heavy torque load. Such a condition may occur, for example, as a result of one auger having more tightly compacted a mass of paving material against its adjacent hopper side wall means or the adjacent gauge sled member, to be later described, than that compacted, if at all, by the other auger against its adjacent side wall means or gauge sled member.

Such condition also may occur if rotation of one only of the augers is obstructed by a rock or other foreign object in the paving material. In the latter instance, the obstructed auger then may stop rotation and the unobstructed auger would then rotate at about twice its normal rotational speed. In order to dislodge the obstruction, such as by crushing the same between the auger and the rear end wall means 24a or the bib portion 24a' thereof, the operator may close the auger control valves 106, 106a to stop rotation of both augers 100, 100a and then open or jog that control valve which controls rotation of the then obstructed auger to greatly increase the rotational force transmitted thereto by the corresponding auger drive motor. Also, the direction of rotation of the corresponding auger may be readily reversed by manipulation of the corresponding auger control valve to facilitaate dislodging the aforementioned rock or foreign object from the obstructed auger so that the rock or foreign object will then fall through the hopper discharge opening 56 and onto the surface being paved.

To avoid fracturing the obstructed auger or adjacent components of the paving machine in the event that the rock or other foreign object cannot be crushed, mutilated or dislodged from the obstructed auger upon a predetermined safe maximum rotational force being applied to the obstructed auger, a pre-adjusted bypass safety valve 110 (FIG. 15) of conventional or other construction is interposed in the fluid pressure circuit between the output side of the pump unit 31b and tank 32. As shown in FIG. 15, bypass safety valve 110 is interposed in a fluid conduit line 111 extending from the high pressure manifold 72 to return conduit 76. Upon build-up of pressure in the high pressure conduit 72 to a predetermined maximum, as may occur upon existence of the last mentioned condition of an obstructed auger, bypass valve 110 opens automatically to permit the fluid being discharged from pump unit 31b to bypass the valves connected to high pressure manifold 72 and to return to the reservoir or tank 32.

In the event of both sets of drive wheels 21, 21a being obstructed, or one of the control vales 35, 35a therefor being closed and the other of the latter valves being opened to drive an obstructed set of the drive wheels, a bypass safety valve 112, interposed between the high pressure conduit 33 and the lower pressure or exhaust conduit 39, will operate upon a predetermined maximum pressure being present in the high pressure conduit 33 to return the fluid being discharged from the pump unit 31a to the reservoir or tank 32 and thereby avoid fracture or other damage to the drive wheel axles 26, 26a or to the drive mechanism connected thereto.

SCREED MEANS

The screed means 25 comprises an elongate, relatively narrow, main screed 25a of hollow construction and of a length about the same as that of the width of main frame 20 and hopper 24 when measured parallel to the rotational axis of drive wheels 21, 21a. Main screed 25 is positioned rearwardly of and adjacent rear wall means 24a of hopper 24, and the front wall of main screed 25a curves upwardly past the top wall of main screed 25a and is pivotally connected, as at 25b (FIGS. 6, 7, 8 and 9), to a screed supporting lower frame member 25c. Frame member 25c is secured to the rear surface of a lower guide member 25d above which the upper front portion of frame member 25c extends. Guide member 25d is suitably secured to the front lower portion of a substantially vertically disposed screed support plate 25e whose upper portion also has an elongate guide member 25f, and an elongate upper frame member 25g suitably secured thereto and corresponding to the respective members 25d, 25c.

The rear portion of main screed 25a is supported adjacent opposite ends thereof; i.e., adjacent opposite sides of the paving machine, by a pair of vertically adjustable links, each of which comprises a lower internally threaded link member 25h (FIGS. 6, 7 and 8) pivotally connected to the upper wall of main screed 25a and into which the lower portion of a screw 25i is threaded. The upper portion of screw 25i loosely penetrates an upper sleeve member 25j pivotally mounted intermediate its end on the rear portion of a substantially horizontally disposed arm 25k whose front end portion is welded or otherwise suitably secured to frame member 25g. A hand crank 25m is fixed on the upper end of each screw 25i. Thus, by rotating the hand cranks 25m, main screed 25a may be pivotally adjusted to vary the angle of the lower surface thereof, as desired, relative to the surface to be paved and thereby to obtain the desired density of the paving strip bieng formed.

Opposed end portions of screed support plate 25e project outwardly a relatively short distance beyond opposing sides of hopper 24 and have the upwardly projecting rear ends of respective lever arms 25p, 25q fixedly secured to the front surface thereof (FIGS. 1-5, 7 and 9). Lever arms 25p, 25q extend forwardly past opposing ends of the two sets of drive wheels 21, 21a and have their front portions pivotally connected to front frame member 20a of main frame 20, thus serving to stabilize main screed 25a against any substantial lateral move-ment with the respect to the path of travel thereof with hopper 24.

Main screed 25a is suspendingly supported for substantially free vertical movement relative to hopper 24, and also may be raised and lowered varying distances through power means controlled by an operator. To this end, it will be observed in FIG. 2 that a right-hand portion of frame member 25g has a relatively short tubular guide member 117 suitably secured thereon, which guide member is preferably of polygonal internal cross-section and has a mating slide bar 118 mounted therein and projecting outwardly from opposite ends thereof. The end of the piston rod 119 of a double-acting screed lifting ram or cylinder 120 is suitably secured to the right-hand end portion of slide bar 118 as shown in FIG. 2, and the left-hand end of ram 120 is connected, as at 122, to frame member 25g.

Opposite ends of slide bar 118 have corresponding ends of respective pliable elements or cables 123, 123a attached thereto, both of which extend to the left from the corresponding ends of slide bar 118, pass beneath and upwardly from respective pulleys 124, 124a and are connected at their upper portions to respective arms 125, 125a. Arms 125, 125a extend forwardly and are suitably secured to upper portions of rear end wall means 24a of hopper 24. Pulleys 124, 124a are rotatably mounted in suitable brackets attached to upper screed supporting frame member 25g.

Opposite ends of cylinder 120 are connected by conduits u, v to the output side of a manually operable control valve 130 (FIG. 15). Control valve 130 may be of the same type as those heretofore described and also has a conduit w leading from the output side thereof to low pressure manifold 75. Fluid pressure is directed to valve 130 by means of a conduit 131 extending between valve 130 and high pressure manifold 72.

It is thus seen that, by manipulating valve 130, piston rod 119 may be extended and retracted relative to cylinder 120 and, upon being extended, piston rod 119 imparts left-to-right movement to slide bar 118 in FIG. 2, thus moving the lower portions of cables 123, 123a therewith so that the pulleys 124, 124a will move upwardly along the vertical reaches of cables 123, 123a to raise main screed 25a. Obviously, upon piston rod 119 being retracted, screed 25a may be lowered the desired amount and to the extent of simply resting upon the surface to be paved or the paving material being spread.

SCREED EXTENSIONS

Fluid operated, extensible and retractable, right-hand and left-hand screed extensions 140, 140a and associated gauge sled members 141, 141a are provided at opposite sides of main screed 25a. Only right-hand screed extension 140 and its gauge sled member 141 will be described in detail with reference to FIG. 9, since, with the exception of left-hand screed extension 140a being oppositely constructed with respect to right-hand screed extension 140, they are essentially of the same construction. In order to direct paving material from hopper 24 to screed extensions 140, 140a, the rear lower corner portions of side wall means 24b, 24c are provided with respective side discharge openings 24e, 24f (FIGS. 1, 2 and 14) which may be about the same size as or somewhat larger than the adjacent ends of augers 100, 100a, although the lower portions thereof are partially closed by the relatively narrow lower portions of lever arms 25p, 25q during normal operation of the paving machine. The side discharge openings 24e, 24f are aligned with augers 100, 100a so that the augers will force the paving material outwardly from the hopper through the openings 24e, 24f, and against the adjacent surfaces of the sled members 141, 141a to ensure that the paving material is of the desired density as it is being directed to the screed extensions 141, 141a.

As shown in FIG. 9, screed extension 140 comprises a substantially C-shaped compacting member or screed plate 140b which loosely penetrates the adjacent side wall of main screed 25a and is slidably supported on the bottom wall and against the front wall of main screed 25a. Compacting member 140b extends upwardly between the top and front walls of main screed 25a and is slidable between guides 140c, 104d suitably secured to the respective bottom and front walls of main screed 25a.

A tubular guide member 140e is welded or otherwise suitably secured to lower supporting frame member 25c of main screed 25a and has an extension bar 140f mounted for longitudinal sliding movement therein. A bracket 140g serves to secure the outer or free end portion of extension bar 140f to a substantially vertically disposed slide plate 140h supported for longitudinal sliding movement between the guide bars 25d, 25f carried by screed support plate 25e. A rearwardly projecting finger or pin 140i is secured to the outer end portion of extension bar 140f and loosely penetrates a vertically extending slot 140j extending through the substantially vertical outer end portion of compacting member 140b.

A double-acting fluid-operated, screed extension arm or cylinder 140k is mounted on and suitably secured to tubular guide member 140e. The outer end of a piston rod of ram 140k is connected, as at 140n, to an outer end portion of extension bar 140f. A separate manually operable control valve 140p, of the same general type as valve 35, is provided (FIG. 15) for control the flow of fluid to opposite ends of each respective fluid-operated ram or cylinder 140k. Each valve 140p has corresponding ends of four conduits a' - d' connected thereto, the other ends of conduits c' , d' being connected to the respective manifolds 72, 75. The two pairs of conduits a' , b' connect valves 140p to the respective right-hand and left-hand screed extension cylinders or rams 140k so that, by manual manipulation of control valves 104p, the screed extensions 140, 140a may be telescoped; i.e., extended and retracted, relative to main screed 25a, as desired, together or independently of each other.

All of the manually operable control valves 31c, 35, 35a, 70, 70a, 87, 106, 106a, 130, 140p, 140q are preferably suitably mounted on the rear surface of rear end wall means 24a, as by means of a common bracket 143 (FIG. 2), so as to be conveniently accessible to an operator standing upon main screed 25a, with adjacent portions of the fluid conduits extending from the control valves being positioned in a suitable casing 144 carried by rear end wall means 24a. As shown in FIG. 6, rear end wall means 24a is also provided with an opening 145 therethrough which communicates with the interior of housing 104 so that most of the fluid conduits extending from the control valves may extend through housing 104 to the pump means 31, reservoir 32, fluid-operated motors 36, 36a, 105, 105a (FIG. 5), rams 62 (FIG. 3) and ram 85 (FIGS. 6 and 7) all of which are positioned substantially within the vertical plane of hopper 24 and are normally covered by lower wall means 44.

Gauge sled member 141 comprises a substantially vertically disposed paving retaining or shield plate 141b having a runner 141c defining the lower edge thereof and being curved upwardly at its front portion to facilitate sliding movement of runner 141c over the surface to be paved. The rear end portion of shield plate 141b preferably terminates in substantial alignment with or forwardly of the rear end wall of main screed 25a, and the front edge of shield plate 141b terminates forwardly of the lateral plane of the adjacent side discharge opening 24e. Also, the height of at least the forward portion of shield plate 140b should be such that its upper edge will be disposed above the level of the upper extremity of the adjacent side discharge opening 24e whenever runner 141c is engaging the ground adjacent the surface to be paved, while allowing for various thicknesses of paving material to be spread upon the surface.

Means are provided for pivotally connecting gauge sled member 141 to, and for facilitating vertical adjustment of gauge sled member 141 relative to, the outer end portion of the corresponding screed extension 140. To this end, a medial portion of shield plate 141b has a vertically extending adjustment slot 141d (FIG. 9) therethrough, through which a pivot pin 141e loosely extends and is pivotally embedded in the outer end of extension bar 140f, preferably by being threaded thereinto. The outer portion of pivot pin 141e is suitably secured to or formed integral with a block 141f having a substantially vertically extending, externally threaded post or rod 141g integral therewith or otherwise suitably secured thereto. Threaded rod 141g is engaged by an internally threaded sleeve 141h whose upper portion is rotatably mounted in and suitably restrained from axial movement in an angle bracket 141i welded or otherwise suitably secured to the upper portion of shield plate 141b. A hand crank 141j is connected to the upper end of internally threaded member 141h to facilitate adjusting the same to raise and lower the shield plate 141b and its runner 141c relative to its pivot pin 141e and, thus, relative to the corresponding screed extension 140.

METHOD OF OPERATION

For purposes of this disclosure, it may be assumed that the fluid system described heretofore is a hydraulic system and that motor 30 is rated at about 13 horsepower at 3,600 revolutions per minute and is normally operated at about 2,200 revolutions per minute, at which speed the output of pump units 31a, 31 b may be about 10 and 13 gallons per minute, respectively, at up to about 1,500 or more pounds per square inch gauge pressure. However, with both augers 100, 100a operating under about the same torque load relative to each other, and with both sets of drive wheels 21, 21a operating under about the same torque load relative to each other, each of the drive motors 36, 36a, 105, 105a may be subjected to a fluid pressure of about 700 to 800 pounds per square inch.

In actual operation of a paving machine constructed according to this invention, and utilizing the fluid pressures last described above, the normal paving speed of the machine was about 32 feet per minute with the augers 100, 100a rotating at a speed of about 35 revolutions per minute. However, when the paving machine is to be moved from place to place under its own power without dispensing paving material from the hopper 24 thereof, the mechanisms controlled by those valves connected to manifolds 72, 75 (FIG. 15) need not be operated. Therefore, the manually operable switching valve 31c, which is closed otherwise, may be operated to switch the fluid output of pump unit 31b to that of pump unit 31a and thereby substantially increase the rate of flow of the fluid through the drive wheel motors 36, 36a. This may more than double the linear speed of the paving machine over the ground without changing the output speed of motor 30. In the actual machine a speed of 74 feet per minute was obtained.

Assuming that main screed 25a or the sled members 141, 141a are resting upon the ground, the screed lift control valve 130 (FIG. 15) is operated manually, before the switching valve 31c is moved to the latter position, so as to raise screed means 25 to a convenient transportable position, such as that shown in FIG. 7. Also, screed extension control valves 140p, 140q may be operated, if desirable, to fully retract screed extensions 140, 140a so that the side discharge openings 24e, 24f (FIGS. 1 and 2) will be substantially closed as the shield plates 141b engage lever arms 25p, 25q.

Of course, if the paving machine is to be moved a considerable distance; e.g., several miles, switching valve 31c may remain in that position in which it causes the fluid to flow from pump unit 31 to manifold 72, and instead, the motor 30 would be shut off and the shipper handles 42m would be moved outwardly from the position of FIG. 11 so as to disengage both of clutches 42. By connecting a suitable draft bar to the front end of the paving machine and to a pulling vehicle in the manner heretofore described, and with the screed means 25 occupying the raised position of FIG. 7, the paving machine then may be pulled to any desired location by any suitable powered vehicle, thus obviating the need for loading the machine on a special trailer or turck to transport the same over long distances.

Upon reaching the paving site, the draft bar is removed from the front end of the paving machine, and the shipper handles 42m are returned to the position shown in FIG. 11 to re-engage the clutches 42. Motor 30 then is started and, with switching valve 31c closed, control valve 130 is manually operated to partially lower screed means 25, if desired, to a more convenient position so that the operator may mount and stand on main screed 25a. The operator then manipulates the drive wheel control valves 35, 35a (FIG. 15), to drive the paving machine forwardly or rearwardly, as desired, to position the same over the surface to be paved. It should be noted that control valves 35, 35a also are used to steer the paving machine by relatively varying the amount of fluid directed to the motors 36, 36a sufficiently to overcome torque limiter 40 and thereby vary the speed and/or direction of rotation of the respective sets of drive wheels 21, 21a relative to each other when desired.

A truck then may be backed up to the front end of hopper 24 to dump a supply of paving material into hopper 24 with the truck bed overlying the front portion of the lower wall means 44 of hopper 24 in the manner heretofore described. The level of shelves 54b, 54b' should be such as to permit the rear portion of the bed of a relatively large, so-called tandem-wheel dump truck to pass thereover. Regardless of whether the dump truck is of the standard or large size described, since the capacity of the bed of the truck may be substantially greater than the capacity of hopper 24, it usually is desirable to have the rear portion of the truck bed overlie the front portion of the lower wall means 44 of hopper 24 during the paving operation. In this instance, the rear wheels of the turck T (FIG. 3) are brought into engagement with the rollers 80, 80a, and the operator then manipulates receptor control valve 87 to cause actuator cam 81 (FIGS. 6 and 7) to push the receptor 54e upwardly so that the reinforcing bar 54f thereon is yieldably urged against the lower surface of a rear portion of the truck bed or frame, preferably immediately forwardly of the rear spring shackels as shown in FIG. 3. Because of the compact construction of the paving machine, the distance from the front of rollers 80, 80a to the axis of augers 100, 100a, or to hopper discharge opening 56, may be 4 feet or less, thereby ensuring that the paving material may be dumped from conventional size dump trucks directly onto the augers above the discharge opening through which the paving material gravitates directly onto the surface being paved. This has not been practicable heretofore to my knowledge.

With truck T in the position of FIG. 3, hand cranks 25m (FIG. 2) then may be adjusted to position the lower surface of main screed 25a at the desired angle so as to obtain the desired compaction of the paving material to be deposited on the surface therebeneath, and hand cranks 141j are rotated to position the lower surfaces of the runners 141c of gauge sled members 141, 141a the desired distance below the level of the lower surface of main screed 25a in accordance with the desired thickness of the paving material to be spread. It may be desirable to form a feather edge on either or both side portions of the paving strip, in which instance the corresponding gauge sled member or members may be adjusted upwardly relative to the main screed 25a so that the corresponding runner or runners thereof are positioned at or above the level of the lower surface of main screed 25a.

In either event, screed means 25 then is lowered to the desired position, either with the runners 141c resting upon the ground, or with the lower surface of main screed 25a occupying a predetermined distance spaced above the ground in the event of the lower surfaces of the gauge sled members being disposed above the level of the lower surface of screed 25a. If the paving strip to be formed is to extend the full width of hopper 24, both of the discharge gates 57, 57a are then opened in the manner heretofore described by manipulation of control valves 70, 70a. The operator then manipulates control valves 35, 35a to drive the wheels 21, 21a and thereby perform the paving operation, during which the paving machine pushes the truck T in front of the same and also during which the reinforcing bar 54f on receptor 54e prevents the truck T from moving forwardly away from the paving machine, even though the rear portion of the truck chassis may tilt upwardly or downwardly relative to the paving machine because of the truck starting to move along an incline before such incline is reached by the paving machine.

The augers 100, 100a generally need not be rotating during paving if the screed extensions 140, 104a and sled members 141, 141a are fully retracted, since the paving material in hopper 24 is usually satisfactorily distributed when it is deposited therein by a dump truck. If the paving machine is moving along over a steeply laterally inclined surface, such that the paving material may gravitate toward the lower side of the hopper, then it may be desirable to operate one or the other or both of the augers 100, 100a to redistribute the paving material. However, rotation of augers 100, 100a is desirable, if not necessary, when the respective screed extensions 140, 140a are extended to increase the width of the paving strip being formed.

It is apparent that, if the paving strip is to be extended outwardly in width relative to either side of the hopper 24, the respective screed extensions 140, 140a may be adjusted outwardly by manual manipulation of the corresponding control valves 140p, 140q (FIG. 15). More importantly, the powered operation of screed extensions 140, 140a facilitates the forming of a paving strip of progressively increasing width, for example, without the necessity of repeatedly stopping the paving machine and without the operator necessarily stepping off the main screed 25a to adjust the screed extensions. For example, the major portion of a paved strip being formed may be of about the same width as the hopper 24; e.g., about 8 feet wide, with the screed extensins 140, 140a and the gauge sled members 141, 141a occupying fully retracted position. However, by manual manipulation of screed extension valves 140p of FIG. 15, both screed extensions 140, 140a may be moved outwardly progressively in relatively small increments, if desired, during the forward travel of the paving machine to provide a somewhat tapered or curved and gradually increasing width to the paving strip being formed and so that the width of the enlarged portion of the paving strip may be up to about 12 feet wide, for example. Of course, it is apparent that only one of the screed extensions 140, 140a and the adjacent auger need be operated if it is desirable to increase the width of the paving strip at one side only thereof.

In some instances, as in paving an automobile parking area, for example, it may be desirable to move the truck T (FIG. 3) away from the paving machine after the hopper 24 has been filled with paving material, especially if the parking area is so confined that the truck could not be accommodated in front of the paving machine as it approached the end of the laying of a particular strip of paving material. Also it is obviously necessary for the truck to be moved away from the paving machine when the truck must replenish its supply of paving material. In either instance, in the event that any of the paving material being transferred from the truck bed into the hopper may have accumulated in receptor 54e, receptor 54e may be moved upwardly to the position of FIG. 7, in the manner heretofore described, to transfer any paving material therein onto the inclined bottom panel 54 of hopper 24, after which receptor 54e may be returned to its normally lowered position shown in FIG. 6.

In the paving of rather restricted areas, such as parking lots, the paving machine disclosed herein has many advantages over other paving machines proposed heretofore. One such advantage is, of course, the compact construction of the paving machine, but more important advantages reside in the facility with which the paving machine may be turned around to face in the opposite direction upon completion of the formation of a given paving strip and preparatory to the formation of another immediately adjacent paving strip. In carrying out this procedure, after a supply of paving material has been deposited in hopper 24 and the truck has moved away from the paving machine, receptor 54e may be raised from the position of FIG. 6 to that of FIG. 7 and the paving machine is propelled under its own power to lay a first strip of paving material on the surface to be paved, during which the screed means 25 occupies the lowered position shown in FIG. 6 and is supported by means of the gauge sled members 141, 141a sliding upon the ground. Both discharge gates 57, 57a would be opened, and both sets of drive wheels 21, 21a would be driven in the manner heretofore described. Also, if both extensions 140, 140a have been extended, both augers 100, 100a would be driven.

Upon reaching the end of the laying of the first paving strip, the operator may manipulate valves 70, 70a, 130 to close the discharge gates 57, 57a, and raise main screed 25a, screed extensions 140, 140a and gauge sled members 141, 141a so that all of the screed components 25a, 140, 140a, 141, 141a will clear the previously laid paving strip as the paving machine is turned to face in the opposite direction preparatory to forming a second paving strip immediately adjacent the first paving strip. The paving machine may be turned substantially about its own vertical axis or an axis anywhere between the extremities of the two sets of drive wheels, for example, by manipulating control valves 35, 35a so that one set of drive wheels 21 or 21a will rotate in a forward direction while the other set of drive wheels rotates in a rearward direction, thus requiring a relatively small area within which to turn the paving machine preparatory to forming the second paving strip.

Upon moving the paving machine into the latter position, that sled member 141, 141a then positioned adjacent the first paving strip may be adjusted upwardly relative to the main screed 25a to position the runner 141c thereof substantially flush with the lower surface of main screed 25a so that it may ride upon the previously formed first paving strip during forming of the second paving strip. The operator then manipulates control valves 70, 70a, 130 to open gates 57, 57a and return main screed 25a to the lowered or operative position whereupon the second paving strip is laid in juxtaposition to the first paving strip. In the event that the second paving strip is to be laid relatively narrow as compared to the first paving strip; e.g., 4 to 6 feet wide, it is apparent that one of the discharge gates 57 or 57a may remain closed while the other is open during the laying of the second paving strip. If the second paving strip is to be laid wider than one-half the length of main screed 25a, but is to be of lesser width than the full length of screed 25a, the operator may cause one of the extensions 140 or 140a to be extended the desired distance and may cause the adjacent distributing auger 100 or 100a, to rotate while the other screed extension may remain fully retracted and the other auger may remain inactive.

Means may be provided at the central portion of main screed 25a for maintaining the lower surface thereof in a straight line, or for bowing the central portion thereof upwardly or downwardly to lay paving strips which are respectively flat or have a convex or concave upper surface. The screed bowing means is of the general type disclosed in my U.S. Pat. No. 3,291,012 dated Dec. 13, 1966, and comprises two spaced apart substantially parallel telescopically adjustable links 150 (FIG. 5) whose opposite ends are pivotally connected to respective pairs of posts 150a, 150b. Posts 150a are welded or otherwise suitably secured to a right-hand portion of the top wall of main screed 25a, and posts 150b are suitably secured to a left-hand portion of the top wall of main screed 25a, which right-hand and left-hand portions are separated at their proximal edges to provide a gap therebetween which is covered by a suitable cover plate 150c. The central portion of each of the front and rear walls of main screed 25a also has a similar gap therein so that the lower wall of main screed 25a may be bowed upwardly or downwardly at its central portion by telescopically adjusting links 150. Each of the links 150 comprises a pair of aligned externally threaded rods 150d which are threaded into opposite ends of an internally threaded sleeve 150e. Sleeves 150e, 150d are interconnected by a sprocket and chain combination 150f so that a bar or rod, not shown, may be inserted in one side of the rearmost sleeve 150e and it may be manually rotated in the desired direction to effective rotation of both sleeves 150e and thereby increase or reduce the effective length of links 150 and thereby bow the central portion of the lower wall of main screed 25a upwardly or downwardly, as desired.

MODIFIED FORM OF PAVING MACHINE

Essentially, the modified form of the paving machine shown in FIGS. 16-18 is constructed and operated in substantially the manner described with respect to the first form of the invention, with the exception of the arrangement of the drive means for the distributing augers, the means for raising and lowering the truck bed receptor, and the provision of means for raising and lowering the bottom wall panel of the hopper. Therefore, those parts shown in FIGS. 16-18 which are substantially the same as corresponding parts shown in FIGS. 1-15 will bear the same reference characters, where applicable, with the prefix "A" added thereto to avoid repetitive description.

The modified arrangement of the drive means for the augers A100, A100a obviates the need for obstructing the central lower portion of hopper A24 to the extent at which the hopper 24 of the first embodiment is obstructed by the housing 104 (see FIG. 6), and it also facilitates raising and lowering the bottom wall panel A54 without first removing other structure such as the housing cover 104' of FIG. 6. To this end, it will be observed in FIGS. 16 and 18 that, instead of the middle frame member, such as that indicated at 20e in FIGS. 6 and 7, extending through the proximal portions of the lower wall panel and the discharge gates for supporting proximal ends of the auger shafts, the proximal ends of the shafts of augers A100, A100a are journaled in suitable bearings carried by a relatively short frame member 160 suitably secured to and extending forwardly from the rear end wall means A24a and whose front end is spaced rearwardly from the hinged lower edge of bottom wall panel A54 of hopper A24. A suitable housing 161, which is substantially U-shaped in plan, is removably secured to the front surface of rear end wall means A24a, as by screws 162 (FIG. 18). The bottom wall of housing 161 is positioned against the lower surface of frame member 160 and the lower portion of the front wall of housing 161 also is spaced rearwardly from the hinged lower edge of hopper bottom wall panel A54. The auger motors A105, A105a are spaced a substantial distance above frame member 160 and are suitably adjustably mounted in an opening 163 provided in an upper portion of rear end wall means A24a. Sprocket and chain transmissions 164, 164a (FIGS. 16 and 18) drivingly connect the motors A105, A105a to the shafts of the respective augers A100, A100a. It will be observed in FIGS. 16 and 18 that the front portions of the motors A105, A105a and the sprocket and chain transmissions 164, 164a are also disposed within housing 161.

Auger motors A105, A105a may be of the same type as, and may be operated in the same manner as, the auger motors 105, 105a of the first embodiment of the paving machine, therefore, a further description thereof is deemed unnecessary. It is to be noted, however, that the arrangement of the auger drive means in FIGS. 16 and 18 provides an unobstructed passage between housing 161 and the hinged rear portion of hopper bottom wall panel A54 for the passage of the paving material therebetween in its course to the discharge opening of the hopper. Also, since housing 161 is spaced forwardly of bottom wall panel A54, panel A54 may be raised and lowered without disturbing housing 161.

Instead of bottom wall panel A54 being secured to the side wall means of hopper A24, as is the case with respect to bottom wall panel 54 of the first embodiment of the paving machine, the upper end of the piston rod of a suitable double-acting fluid pressure ram 170 is pivotally connected to a medial portion of the bottom wall panel A54 of FIG. 16, adjacent to but rearwardly of truck bed receptor A54e. The cylinder of ram 170 is pivotally connected at its lowered end to one of the frame members A20b adjacent the front portion of main frame A20. Conduits 170a, 170b extend from opposite ends of the cylinder of ram 170 to a manually operable control valve 171 which may be of the same type as valve 35 heretofore described and which may be connected to the manifolds 72, 75 of FIG. 15 in the same manner as valve 106a, for example. Valve 171 (FIG. 16) may be positioned at any convenient location, preferably adjacent the valves shown in the upper left-hand portion of FIG. 2, so as to be manipulated by an operator standing on the screed means A25 of the modified form of paving machine.

As heretofore described with respect to the first embodiment of the paving machine, the double-acting ram or cylinder 85 (FIGS. 6 and 7) for raising and lowering the receptor 54e is carried by the main frame 20. However, in the modified form of the paving machine, it will be observed in FIGS. 16 and 17 that the lower end of the cylinder A85 is pivotally connected to the rear lower portion of bottom wall panel A54, as at 175, closely adjacent the hinge or pivot shaft A60 and the upper or forward end of piston rod A84 is pivotally connected to the forward portion of a slide member 176 (FIG. 17) guided for longitudinal sliding movement in a tubular guide member 177 welded or otherwise suitably secured to the lower surface of bottom wall panel A54. A link 180 connects the slide member 176 to a medial portion of the rear wall of receptor A54e. The receptor ram A85 may be connected to valve 87 (FIG. 15) in the same manner as that described for receptor ram 85 of the first embodiment of the paving machine and, accordingly, a further description thereof is deemed unnecessary.

In operation, it is apparent that hopper bottom wall panel A54 and receptor A54e may be raised and lowered unitarily by manipulation of valve 171 and, regardless of the position of hopper bottom wall panel A54, receptor A54e may be pivoted between the solid line position shown in FIG. 16 and the broken line position of FIG. 16, for example, by controlling the direction of flow of fluid pressure into the cylinder A85. Although the bottom wall panel A54 normally occupies the lower, solid-line position shown in FIG. 16 during the paving operation, when the paving machine is moving forwardly along a down grade and the supply of paving material in hopper A24 may be relatively low, the operator need only manipulate valve 171 so as to raise the bottom wall panel A54 to substantially the broken line position shown in FIG. 16 to prevent the paving material thereon from adhering thereto and to insure that the paving material will gravitate against the augers A100, A100a and though the then open discharge opening in the rear lower portion of hopper A24.

Since the housing 161 in FIGS. 16 and 18 does not provide communication between the outer surface of the rear end wall means A24a and the space beneath the bottom wall panel A54, such as is provided by the housing 104 in FIGS. 6 and 7, and it is desirable to mount the various control valves for the paving machine on the rear surface of the rear end wall means A24a of hopper A24 in a manner such as that shown in FIG. 2, the various conduits from such control valves in the modified form of the paving machine may extend outwardly from the control valves and along the outer surfaces of opposing side wall means of the hopper A24 and then may extend inwardly to the various fluid-operated means disposed beneath the bottom wall panel A54 and receptor A54e in FIG. 16. In other respects, the modified form of paving machine may be constructed and operated in the manner described with respect to the first embodiment of the paving machine, and, accordingly, a further description thereof is deemed unnecessary.

In the drawings and specification, there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

Claims

That which is claimed is:

1. A self-propelled paving machine comprising a frame, a plurality of substantially axially aligned drive wheels supporting said frame for movement over a surface to be paved, motive means carried by said frame, drive mechanism connecting said motive means to said drive wheels and also carried by said frame, a hopper carried by said frame and adapted to receive paving material therein, a lower portion of said hopper rearwardly of said drive wheels having a discharge opening therein for discharging paving material from said hopper onto the surface to be paved, a substantially vertically movable main screed carried by said paving machine and positioned rearwardly of said hopper for smoothing and compacting the paving material during movement of the machine over the surface to be paved, a screed extension carried by at least one side portion of said screed, power means for extending and retracting said screed extension relative to said main screed, manually operable control means operatively connected to said power means for controlling the same, a substantially vertically disposed shield plate carried by and positioned adjacent the outer end of said screed extension, said hopper having side wall means provided with a side delivery opening therein adjacent said screed extension, and a rotary auger in said lower portion of said hopper for forcing paving material therein outwardly through said side delivery opening and against said shield plate to be smoothed and compacted upon said surface by said screed extension.

2. A structure according to claim 1, including drive means drivingly connected to said rotary auger for rotating the same and including means responsive to predetermined compaction of paving material against said shield plate by said auger for stopping rotation of said auger.

3. A self-propelled paving machine comprising a frame, a plurality of substantially axially aligned drive wheels supporting said frame for movement over a surface to be paved, motive means on said machine, drive mechanism connecting said motive means to said drive wheels and carried by said frame, a hopper carried by said frame and adapted to receive paving material therein, a lower portion of said hopper rearwardly of said drive wheels having a discharge opening therein for discharging paving material from said hopper onto the surface to be paved, a truck engaging means carried by a front portion of said frame and adapted to engage a rear portion of the truck for pushing the same during a paving operation, a lip mounted for vertical movement on a forward portion of said paving machine, and a manually controlled fluid operated ram interposed between said frame and said lip for raising and lowering said lip into and out of engagement with a lower surface of a portion of the truck overlying said lip and causing said lip, when raised, to engage said lower surface under pressure such that said lip will apply braking force to the truck to prevent the rear portion thereof from moving away from said truck engaging means during a paving operation.

4. A compact self-propelled paving machine comprising a frame, a plurality of drive wheels supporting said frame for movement over a surface to be paved, motive means carried by said machine, drive mechanism connecting said motive means to said drive wheels and carried by said frame, a hopper carried by said frame and substantially completely overlying said drive mechanism and said drive wheels, a lower portion of said hopper rearwardly of said drive wheels having a discharge opening therein for discharging paving material from said hopper onto the surface to be paved by gravity, said drive mechanism and said drive wheels being compactly arranged whereby the rear portion of a conventional dump truck may overly a front portion of said hopper and paving material may be dumped from the truck to gravitate directly from the truck toward said discharge opening, said hopper comprising substantially upright rear end wall means and spaced side wall means, a lower wall means defining the bottom of said hopper and including a downwardly and rearwardly inclined bottom panel extending between said spaced side wall means, said bottom panel extending over and across said drive wheels with its lower rear edge spaced forwardly from said rear end wall means to define said discharge opening therebetween, said lower wall means further comprising a receptor adapted to receive thereover a lower rear portion of a truck bed, said receptor including a bottom panel normally occupying a substantially horizontal position, means pivotally supporting a rear portion of said receptor for vertical pivotal movement relative to said inclined bottom panel, and manually controlled power means operatively associated with said motive means for raising said receptor about its pivot whereby any paving material deposited thereon may be caused to gravitate toward said discharge opening when the truck bed is removed from over said receptor.

5. A structure according to claim 4, wherein said manually controlled power means for raising said receptor comprises a fluid-operated pump means driven by said motive means, a fluid-operated ram interposed between said frame and said receptor and connected to said pump means, and manually operable valve means interposed in a fluid pressure circuit between said ram and said pump means for controlling the flow of fluid pressure to said ram.

6. A compact self-propelled paving machine comprising a frame, a plurality of drive wheels supporting said frame for movement over a surface to be paved, motive means carried by said machine, drive mechanism connecting said motive means to said drive wheels and carried by said frame, a hopper carried by said frame and substantially completely overlying said drive mechanism and said drive wheels, a lower portion of said hopper rearwardly of said drive wheels having a discharge opening therein for discharging paving material from said hopper onto the surface to be paved by gravity, said drive mechanism and said drive wheels being compactly arranged whereby the rear portion of a conventional dump truck may overly a front portion of said hopper and paving material may be dumped from the truck to gravitate directly from the truck toward said discharge opening, said hopper comprising a lower wall means defining the bottom of said hopper, means pivotally supporting the rear portion of said lower wall means for angular movement about a pivot axis adjacent said discharge opening and extending substantially parallel with said drive wheels, and means operatively associated with said motive means for pivoting said lower wall means about said pivot axis to vary the angular position of said lower wall means.

7. A compact self-propelled paving machine comprising a frame, a plurality of drive wheels supporting said frame for movement over a surface to be paved, motive means carried by said machine, drive mechanism connecting said motive means to said drive wheels and carried by said frame, a hopper carried by said frame and substantially completely overlying said drive mechanism and said drive wheels, a lower portion of said hopper rearwardly of said drive wheels having a discharge opening therein for discharging paving material from said hopper onto the surface to be paved by gravity, said hopper comprising substantially upright rear end wall means and spaced side wall means, a lower wall means defining the bottom of said hopper and including a downwardly and rearwardly inclined bottom panel extending between said spaced side wall means, said bottom panel extending over and across said drive wheels with its lower rear edge spaced forwardly from said rear end wall means to define said discharge opening therebetween, said drive mechanism and said drive wheels being compactly arranged whereby the rear portion of a conventional dump truck may overly a front portion of said hopper and paving material may be dumped from the truck to gravitate directly from the truck toward said discharge opening, and means pivotally connecting the rear lower portion of said inclined bottom panel to said frame along an axis rearwardly of and substantially parallel to the axis of said drive wheels whereby said lower wall means may be tilted upwardly about the pivot point of said bottom panel to facilitate access to said drive mechanism and said drive wheels therebeneath.

8. A structure according to claim 7, wherein said motive means comprises an internal combustion motor on a front portion of said frame, a fluid reservoir carried by a front portion of said frame, and pump means driven by said internal combustion motor, all normally positioned under said lower wall means, said drive mechanism including hydraulic motor means drivingly connected to said drive wheels, fluid conduit means connecting said pump means to said reservoir and said hydraulic motor means, control valve means in said conduit means between said pump means and said hydraulic motor means, and said hopper lower wall means further comprising means integral with and projecting forwardly from said inclined bottom panel and normally overlying said internal combustion motor and said reservoir to shield the same from paving material deposited on said lower wall means and whereby said lower wall means also may be tilted upwardly to facilitate access to said internal combustion motor and said reservoir.

9. A compact self-propelled paving machine comprising a frame, a plurality of drive wheels supporting said frame for movement over a surface to be paved, motive means carried by said machine, drive mechanism connecting said motive means to said drive wheels and carried by said frame, a hopper carried by said frame and substantially completely overlying said drive mechanism and said drive wheels, a lower portion of said hopper rearwardly of said drive wheels having a discharge opening therein for discharging paving material from said hopper onto the surface to be paved by gravity, said drive mechanism and said drive wheels being compactly arranged whereby the rear portion of a conventional dump truck may overly a front portion of said hopper and paving material may be dumped from the truck to gravitate directly from the truck toward said discharge opening, rotary auger means disposed in said lower portion of said hopper to aid in laterally distributing the paving material received thereon for discharge through said opening, additional manually controlled drive mechanism carried by said frame and connecting said motive means to said auger means for rotating the same, said rotary auger means comprising a pair of first and second substantially axially aligned augers each extending throughout substantially one-half of the width of said hopper, a fluid pressure pump means driven by said motive means, and said additional manually controlled drive mechanism comprising first and second fluid-operated motors communicatively connected to said pump means, and means drivingly connecting said first and second fluid-operated motors to the respective first and second augers independently of each other.

10. A compact self-propelled paving machine comprising a frame, a plurality of drive wheels supporting said frame for movement over a surface to be paved, motive means carried by said machine, drive mechanism connecting said motive means to said drive wheels and carried by said frame, a hopper carried by said frame and substantially completely overlying said drive mechanism and said drive wheels, a lower portion of said hopper rearwardly of said drive wheels having a discharge opening therein for discharging paving material from said hopper onto the surface to be paved by gravity, said drive mechanism and said drive wheels being compactly arranged whereby the rear portion of a conventional dump truck may overly a front portion of said hopper and paving material may be dumped from the truck to gravitate directly from the truck toward said discharge opening, screed means mounted for substantially free vertical movement on said frame and positioned rearwardly of said discharge opening in said hopper for smoothing and compacting the paving material as said paving machine moves over the surface to be paved, said screed means comprising a main screed extending widthwise of and being of substantially the same length as the width of said hopper, a screed extension mounted on at least one side portion of said main screed for inward and outward movement relative thereto, manually controlled fluid-operated means for selectively imparting predetermined inward and outward movements to said screed extension, a sled member proximate to the outer end of said screed extension and movable inwardly and outwardly therewith, manually operable adjustment means for raising and lowering said sled member relative to said screed extension whereby said sled member may serve to define the corresponding edge of the material being spread, and said adjustment means including means pivotally connecting a medial portion of said sled member to said screed extension and arranged to permit movement of said sled member about a substantially horizontal axis whereby the position of said sled member about its axis may vary in accordance with the surface over which it is moving in engagement therewith without being encumbered by said screed extension and said screed and without distrubing the position of said screed to any substantial degree when the sled member rides over a relatively small projecting irregularity in its path.

11. A self-propelled paving machine for cooperating with an automotive truck having a dump body for transporting paving material and for delivering paving material from the rearward end of the dump body, the paving machine comprising:

a main frame,

wheel means mounted on said frame for supporting said frame on a surface to be paved,

drive means mounted on said frame and operatively connected with said wheel means for propelling the paving machine along the surface to be paved,

hopper means mounted on said frame for containing paving material to be applied and including wall means for defining a transverse slot through which paving material passes onto the surface to be paved, and

coupling means mounted from said frame in predetermined spaced relation to said hopper means for coupling together the paving machine and a truck and thereby for enlarging the effective capacity of said hopper means by the addition thereto of the effective capacity of the dump body of the truck, and coupling means comprising:

pushing means for engaging the truck forwardly of the rearward end of the dump body and for limiting forward movement of said hopper means beneath the dump body by pushing the truck upon forward movement of the paving machine,

pivotal means mounted at a forward edge of said hopper means for movement between a retracted position withdrawn from engagement with any overlying portion of a truck and an extended position in engagement with any overlying portion of a truck for restraining the truck against forward movement otherwise removing the dump body from above said hopper means, and

means for resiliently biasing the pivoted means toward the extended position,

said coupling means and said hopper means cooperating for positioning said hopper means to underlie the rearward end of the dump body of a truck and to extend from a point forwardly thereof to a point rearwardly thereof during delivery of paving material from the dump body into said hopper means,

whereby paving material may be delivered from the dump body of a truck to which said paving machine is coupled by said coupling means simultaneously with passage of paving material through said hopper means and onto the surface to be paved.

12. A self-propelled paving machine for cooperating with an automotive truck having a dump body for transporting paving material and for delivering paving material from the rearward end of the dump body, the paving machine comprising:

a main frame,

wheel means mounted on said frame for supporting said frame on a surface to be paved,

motive means mounted on said frame for supplying motive power to the paving machine,

drive means mounted on said frame and operatively connected with said motive means and said wheel means for propelling the paving machine along the surface to be paved,

hopper means mounted on said frame for receiving and containing paving material to be applied, said hopper means overlying said wheel means and including a generally vertical stationary rear wall having a predetermined transverse width, spaced apart side walls extending perpendicular to said rear wall at the side edges thereof, and bottom wall means extending between and cooperating with said rear wall and said side walls,

said bottom wall means comprising a trailing portion and a leading portion, each of said portions having a width substantially the same as said rear wall and being mounted for pivotal movement relative thereto about a common transverse axis spaced forwardly of said rear wall, said trailing portion extending rearwardly from said transverse axis and defining with said rear wall a transverse slot through which paving material passes onto the surface to be paved, and said leading portion extending forwardly from said axis to underlie paving material delivered from a truck,

first manually controlled fluid pressure operated means operatively connected with said motive means and said trailing portion for imparting angular movement thereto about said axis and thereby varying the width of the transverse slot defined between said rearward wall and said trailing portion, and

second manually controlled pressure fluid operated means operatively connected with said motive means and said leading portion for imparting angular movement thereto about said axis and thereby for aiding gravitational flow of paving material received from a truck toward said transverse slot.