Paving Apparatus

Abstract

A towed-type paver including a material hopper having a rearwardly and downwardly inclined front wall, a rear wall, and opposite sidewalls, the walls having lower extremities which mutually define a material discharge opening. A multisection shutoff gate is provided for the material discharge opening including a center section and side sections at each side of the center section. The center gate section may be moved alone between open and closed positions, and the side sections may be moved simultaneously with the center section between open and closed positions. A screed is provided adjustably mounted on the rear wall of the hopper and extending rearwardly therefrom. Vehicle- engaging arms extend forwardly from the hopper for selectively engaging a part of a towing vehicle, and a foot-actuated linkage is provided for selectively moving the engaging arms between an upper engaging position and a lower disengaged position. A heating system is provided for heating both the front wall of the hopper and the screed.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to paving apparatus, and more particularly to a paver of the towed-type for spreading and compacting paving material, such as asphalt.

2. Description of the Prior Art

One type of towed paver presently in use is shown in U.S. Pat. No. 3,288,041 to Jack D. Layton. That paver, which is commonly used for laying, compacting and smoothing asphalt on roads, driveways, parking lots and the like, includes a material hopper having a sloping forward wall which in combination with sidewalls and a rear wall define a material discharge opening, the opening being selectively opened and closed by a gate extending the entire length thereof. A screed assembly is pivotally mounted on the rear wall of the hopper and provided with means for adjusting the angle of attack thereof thereby to determine the thickness of the applied layer of asphalt. Screed extensions are adjustably mounted at each end of the screed assembly for selective transverse inward and outward movement. The width of the discharge opening may be selectively varied by blockoff plates attached to the screed extensions and moved inwardly and outwardly therewith. The paver is supported by tracks and towed by means of arms respectively engaging the rims of the wheels of a towing dump truck which thus dumps paving material into the hopper as it tows the paver. The screed assembly of the Layton paver may be heated in the manner shown in U.S. Pat. No. 3,286,606 .

SUMMARY OF THE INVENTION

The present invention, in its broader aspects, provides paving apparatus comprising a material hopper having a sloping front wall, a rear wall, and opposite sidewalls, the walls respectively having lower extremities which mutually define a material discharge opening. Gate means are provided connected to the hopper for selectively opening and closing the opening, the gate means including a center section and at least one side section at each side of the center section thereby to provide openings of varying widths. Means is provided for selectively moving the center section alone between open and closed positions, and for moving the side sections between open and closed positions simultaneously with movement of the center section. Means is provided mounted on the hopper for supporting the apparatus upon a supporting surface for movement thereover in forward and rearward directions, and a screed assembly is provided adjustably mounted on the rear wall and extending rearwardly therefrom. Means are provided extending forwardly from the hopper for selectively engaging a part of a vehicle thereby to tow the apparatus, and foot-actuated means are provided for actuating the engaging means between an upper engaging position and a lower disengaged position. Means are provided for heating both the front wall of the hopper and the screed.

It is an object of the present invention to provide improved paving apparatus.

Another object of the invention is to provide improved paving apparatus of the towed type.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a rear view in perspective showing the improved paving apparatus of the invention;

FIG. 2 is a side view of the paving apparatus of FIG. 1 showing its relationship with a towing dump truck;

FIG. 3 is a fragmentary front view in perspective further illustrating the towing mechanism of the apparatus;

FIG. 4 is a fragmentary view in perspective further illustrating one of the supporting wheels of the apparatus;

FIG. 5 is a top view of the apparatus;

FIG. 6 is a fragmentary side cross-sectional view showing the gate mechanism of the apparatus;

FIG. 7 is a fragmentary view in perspective further showing the gate mechanism;

FIG. 8 is a fragmentary side cross-sectional view showing the gate and lifting mechanism of the invention;

FIG. 9 is a schematic view showing the front wall and screed heating system of the apparatus; and

FIG. 10 is a fragmentary cross-sectional view taken along the line 10-10 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the FIGS. of the drawings, the improved paving apparatus of the invention, generally shown at 12, includes a material-receiving hopper 14 comprising a downwardly and rearwardly inclined front wall 16, a generally vertical rear wall 18, and opposite sidewalls 20 and 22 respectively having upwardly extending extensions or wings 24 and 26 pivotally connected thereto, as by hinges 28 and 30, for movement between closed positions, as shown in FIG. 1, and outwardly inclined positions, as shown in FIG. 5.

As best seen in FIGS. 6 and 10, front wall 16 comprises a sloping top plate 32, a bottom plate 34, a rear end plate 36 joining the rear extremities of the top and bottom plates, the top, bottom, rear and front plates mutually defining a heating chamber 40, as will be hereinafter more fully described (FIG. 9). A generally horizontal plate 42 extends forwardly from the forward extremity of the top plate 32, being disposed between inclined forwardly extending plates 44 and 46. Lifting lugs 48 extend upwardly from the extension plates 44, 46 to permit bodily lifting the entire paver for over-the-road transport.

The lower extremities of the top plate 32 of the front wall 16, the sidewalls 20 and 22, and rear wall 18 mutually define an elongated material discharge opening 50 (FIG. 6). A center gate 52, and side gates 54 and 56 on one side thereof, and side gates 58, 60 on the other side are provided respectively pivotally connected to the lower extremity of the rear wall 18 by suitable hinges 63, and serve selectively to open and close the discharge opening 50, as best seen in FIG. 6. In a physical embodiment of the apparatus in which the hopper 14 is 8 feet wide between the sidewalls 20 and 22, the center gate 52 is 4 feet long, and each of the side gates 54, 56, 58 and 60 is one foot long, thus selectively providing paving widths of 4 feet, 5 feet, 6 feet, 7 feet or 8 feet, an additional width of 2 feet on each side being provided by the adjustable screed extensions to be hereinafter described.

The side gates 54, 56, 58 and 60 are selectively raised and lowered by means of suitable chains 62 which may be selectively engaged with suitable hooks 64 attached to the rear wall 18 adjacent its upper extremity 66, thereby to hold the side gates in their closed positions. Center gate 52 is raised and lowered by means of a suitable chain 68 having a hook 70 at its upper end for attachment over the tail gate 72 of the bed of a towing dump truck 74, as will hereinafter be more fully described.

Side gate 54 has a plate 75 secured to its upper surface and overlaying the upper surface of center gate 52, side gate 56 has a similar plate 76 overlaying side gate 54, and side gates 58 and 60 have similar plates 78 and 80 respectively overlaying center gate 52 and side gate 58. It will now be seen that the side gates 54 and 58, by reason of the plates 75 and 78, can not be lowered to their open positions unless center gate 52 is lowered to its open position, and likewise that the outer side gates 56 and 60 can not be lowered to their open positions unless the center gate 52 is lowered to its open position, and likewise that the outer side gates 56 and 60 can not be lowered to their open positions unless the center gate 52 and the inner side gates 54 and 58 are lowered. However, raising of the center gate 52 from its lowered open position, as shown in dashed lines in FIG. 6, to its upper closed position, as shown in solid lines, will result in simultaneous closing of any of the side gates which are opened by reason of the plate members 75, 76, 78 and 80.

In operation, hook 70 on the chain 68 attached to the center gate 52 is placed over the upper extremity of the tailgate 72 of the dump truck 74. It will readily be seen by reference to FIG. 2 that lowering of the dump bed 82 in the direction shown by the arrow 84 will result in upward movement of the upper extremity of the tailgate 72, as shown by the arrow 86, thus resulting in upward movement of the chain 68, as shown by the arrow 88, thereby closing the center gate 52 together with any of the side gates which may be open. It will be understood that lowering of the dump bed 82 will simultaneously close the tailgate 72 to prevent material from being discharged from the truck body into the hopper. When it is desired to lay paving material, the dump bed 82 is raised thus lowering the upper extremity of the tailgate which permits the center gate 52 to open, the tailgate 72 also opening so that material is discharged into the hopper 14 as shown by the arrows 90. If it is desired to lay a width of paving only as wide as the length of the center gate 52, the chains 62 respectively attached to the side gates are left engaged with their respective hooks 64. However, if it is desired to lay a wider width of paving, the chains 62 of the desired number of side gates are disengaged from their respective hooks 64 and thus, the respective side gates will open simultaneously with opening of the center gate 52. With this arrangement, the need for the blockoff plates of the Layton paver is eliminated since the gates of the present invention can be opened and closed at will by lowering or raising the truck bed a small amount. The gate system of the invention also eliminates the need to empty the paver at the end of a particular spread since, as described, lowering of the truck bed automatically and simultaneously closes all of the gates so that any remaining mix in the hopper can be carried a short distance therein for spreading elsewhere.

A screed assembly 92 is provided comprising a rearwardly extending compacting portion 94 and an upwardly extending mounting portion 96 pivotally mounted on extension members 98 and 100 which extend rearwardly from the hopper, as at 102 and 104. The compacting portion 94 includes a bottom plate 104 having sufficient flexibility to permit deflection upwardly or downwardly to provide a crown or valley in the paving, as will be described shortly. Mounting portion 96 comprises two laterally spaced apart plates 106 and 108 each secured to the bottom plate 104 and adjustably connected by a turnbuckle 110. It will be readily understood that adjustment of the turnbuckle 110 in one direction will draw the upper ends 112, 114 of the plates 106, 108 more closely together thereby deflecting the center portion of the bottom plate 104 downwardly, as shown by the arrow 116, so as to form a valley in the paving 118, whereas adjustment of the turnbuckle in the opposite direction will separate the upper ends 112, 114 of the plates 106, 108 thereby deflecting the center portion of the bottom plate 104 upwardly, as shown by the arrows 120 so as to form a crown in the paving. A plate 122 is attached to mounting plate 108, but not to mounting plate 106, and thus moves with the mounting plate 108 in response to adjustment of the turnbuckle 110. An indicating pointer 124 on the plate 122 cooperating with indicia on rear wall 18 indicates the amount of crown or valley deflection of the bottom plate 104.

The angle of attack of the bottom plate 104 of the screed assembly 92, which determines the thickness of the paving layer 118, is adjusted by means of suitable jacks 126, 128 interconnecting the outer ends 130 and 132 of the compacting portion 94 and the outer ends of the members 98 and 100, as shown. The jacks 126, 128 are independently manually operated by suitable cranks 134, 136, thus permitting tilting or cocking of the entire screed assembly as dictated by the paving needs. The angle of attack of each end 130, 132 of this screed assembly is indicated by a suitable pointer 138 (only one of which is shown in FIG. 1) having one end secured to the upper extremity of the respective mounting plate 106, 108 and its distal end thus indicating the angle of attack on a scale 140 on the respective member 98, 100.

Screed extensions 142, 144 are provided on each side of the paver, each comprising a strikeoff plate 146 and an extension plate 148. Each of the screed assemblies 142, 144 is adjustably mounted for lateral inward and outward movement, as shown by the arrows 150, by means of suitable members 152, 154 journaled in suitable bearing tubes 157, 158 mounted on the respective mounting plate 106, 108. Selective adjustment of the screed extensions 142, 144 is provided by means of members 160 attached to the respective strikeoff plate 146, and moving herewith, and respectively having a roller chain 162 secured thereto. Each of the chains 162 is engaged by a sprocket 164 mounted on a suitable shaft 166 and manually operated by a suitable crank 168.

As best seen in FIG. 6, each of the sidewalls 20, 22 has a cutout portion 170 formed therein communicating with the interior of the hopper thus permitting the material in the hopper to spill outwardly therethrough when the screed extensions 142, 144 are extended. The openings defined by these cutout portions 170 are closed by the strikeoff plates 146 when the screed extensions are in their innermost positions, thus preventing the flow of material through these openings.

The paver is supported for forward and rearward movement over the ground 172 by means of a pair of wide wheels 174, 176. Each of the wheels 174, 176 is mounted beneath the forward end 178 of the hopper by means of a pair of downwardly extending brackets 180, 182. Each of the wheels is rotatably mounted between the pair of brackets 180, 182 by means of a suitable bearing pin (not shown) selectively positioned in one or the other of two openings 184, 186, as best seen in FIG. 4. Thus, each of the wheels 174, 176 may be selectively positioned at two different distances beneath the hopper. This arrangement, in turn, permits independent adjustment of the height of the screed assembly above the ground, separate and apart from the angle of attack adjustment provided by the jacks 126, 128. Thus, when both of the wheels 174, 176 are rotatably attached to the brackets 180, 182 by means of the lower openings 184, the screed assembly has a generally lower position with respect to the ground. On the other hand, when both of the wheels are attached by means of the upper opening, 186, the screed assembly is at a higher elevation, thus permitting the application of a much thicker paving layer, or the laying of crushed rock. Further, mounting of one of the wheels by means of the lower openings 184 and the other by means of the upper openings 186 provides a much greater tilting or cocking of the screed assembly than is available through adjustment of the jacks 126, 128, thus permitting paving of one side of a highly crowned roads where it is desired to provide a thick layer of paving adjacent the outer edge and a thin layer adjacent the crown at the center.

Mud and dirt are removed from wheels 174, 176 by means of suitable scrapers 188, 190 pivotally mounted on the brackets 180, 182 and biased into scraping engagement with the surface of the respective wheel by means of levers 192, 194 connected by a suitable spring 196.

The paver is towed by means of the vehicle-engaging apparatus 198, as best seen in FIGS. 2 and 3. A pair of arms 200, 202 are provided each having a hook portion 204 at its distal end for selectively engaging the axle 206 of the rear wheels 208 of the truck 74. Arms 200, 202 are adjustably received within tubes 210, 212 thereby to accommodate the paver to different types of trucks.

Tubes 210, 212 are respectively attached to tubes 214, 215 which are journaled in bearing members 216, 218 and 220 mounted below the forward end 178 of the hopper. Arms 200, 202 are thus independently mounted for pivotal movement between their lower disengaged and upper axle-engaging positions. An inner rod 221 extends through the tubes 214, 215 respectively extending beyond the opposite ends thereof. Torsion springs 222, 224 respectively connect the outer ends of the tubes 214, 215 and the outer ends of the rod 221, springs 222 and 224 thus biasing arms 200 and 202 upwardly toward their axle-engaging position.

The arms 200, 202 are selectively moved between their lower and upper positions by means of a foot-actuated lever member 226 positioned over the compacting portion 94 of the screed assembly 92 and pivotally mounted on member 100, as at 228. The foot-actuated lever member 226 is connected to lever member 230 on rod 221 by means of a link 232. Lever member 226 is held in its downward position by a suitable latch 234 pivotally mounted on member 100. It will now be seen that downward movement of the foot-actuated lever member 226 will tend to tighten the torsion springs 222, 224, thus causing the arms 200, 202 to independently pivot upwardly to their axle-engaging position. This twin torsion bar arrangement makes it possible for one man to raise or lower the axle-engaging assembly 198 without difficulty. The independent pivotal mounting with the accompanying spring biasing of two arms 200, 202 accommodates up and down motion of the towing truck and tilting of the truck axle so that the paver will not drift on side hills or around short turns.

Suitable rollers 234 are rotatably mounted on the front end 178 of the hopper for engaging the truck wheels 208 thereby permitting the truck to back the paver, as required.

Referring particularly to FIGS. 2 and 8, the center gate lifting chain 68 passes through a bracket 236 on the rear wall 18, chain 68 having an extra link or other abutment 238 thereon. Thus, when the truck bed 82 has been lowered a sufficient distance to close the center gate 52 as above-described, further lowering of the truck bed with concurrent lifting of the chain 68 in the direction 88 will cause the abutment 238 to engage the bracket 236, thus resulting in pivoting of the entire paver about the wheels 174, 176 so as to raise the entire screed assembly 92 above the ground. Thus, automatic raising of the assembly occurs immediately following the closing of the shutoff gates by lowering of the dump truck bed, the rear or screed end of the paver thus being automatically raised at the same time so as to permit the truck operator to maneuver the paver without completely picking it up. This arrangement completely eliminates the hydraulic jacks and chain hoist previously required to raise the screed assembly.

It will be seen that the sidewall extensions or wings 24, 26 are retained in their outward positions by suitable chains 25 and 27, the outward inclination of the wings being adjustable by means of suitable hooks on every wall. These wings thus allow unloading of trucks of different widths, while both the wings and the screed extensions can be withdrawn to permit transport of the paver over the highway.

Referring now particularly to FIG. 9, the chamber 40 within the front wall 16 of the hopper is longitudinally divided into two sections 242, 244. Each of these heating chamber sections is further transversely divided by baffles 246, 248 into forward and rear portions 250, 252 and 254, 256. It will be seen that each of the baffles 246, 248 extends inwardly from the respective sidewall 20, 22 toward the center partition 240, being spaced therefrom to provide openings 258, 260 respectively communicating between the forward and rear chamber portions. Openings 262, 264 are respectively formed in the bottom plate 34 adjacent the sidewalls 20, 22 and the front wall 38.

Angled plates 266, 268 extend between baffle 246 and sidewall 20, and baffle 248 and sidewall 22, and receive and direct suitable burners 270, 272 toward the rear wall 36, as shown. Burners 270, 272 are respectively connected to a tank 274 of suitable fuel, such as liquid propane, by lines 276, 278. It will be seen that the heated products of combustion from the burners 270, 272 travel initially toward the rear wall 36, then inwardly toward the partition 240, forwardly through the openings 258, 260, outwardly toward the sidewalls 20, 22 and the finally exhausted through the openings 262, 264, thus efficiently heating the entire surface area of the top plate 32 of the front wall 16 of the hopper. By so heating the front wall of the hopper, it is possible to handle either hot or cold mixed asphalt directly from an asphalt plant or directly from a stock-pile. In the case of the use of cold mix asphalt, heating the front wall allows the mix to slide more easily down the front wall and smoothly through the discharge opening. Heating the front wall also facilitates the use of hot mix during cold weather.

Still referring to FIG. 9 in contention with FIG. 1, the compacting portion 94 of the screed assembly includes top walls 280, 282 spaced from the bottom wall 104, end walls 282, 286, back walls 288, 290, and inner walls 292, 294 which mutually define with the plates 106, 108, two heating chamber sections 296, 298. Baffles 300, 302 extend outwardly from the inner walls 292, 294 toward the end walls 284, 286 to subdivide the chamber sections 296, 298 respectively into forward and rear portions 304, 306 and 308, 310. The outer ends of the baffles 300, 302 are spaced from the end walls 284, 286, respectively, and in turn have forwardly and rearwardly inclined baffles 312, 314 extending therefrom to defined passageways 316, 318 communicating between the forward and rear chamber portions 304, 306 and 308, 310, respectively.

Burners 320, 322 extend through the inner walls 292, 294 into the forward chamber portions 304, 308 and the products of combustion thus respectively travel outwardly toward the end walls 284, 286, rearwardly through the passageways 316, 318, and then inwardly through the chamber portions 306, 310, being finally discharged through openings 324, 326 in the backwalls 288, 290, as shown. Burners 320, 322 are also connected to the fuel tank 274 removably mounted on the rear wall 18 of the hopper by means of brackets 328 and coil spring loop 330. It is thus seen that the bottom-compacting plate 104 of the screed is uniformly heated throughout its surface area, thus providing efficient smoothing of the paving material 118. Ready access to the burners 320, 322 is provided by a removable cover plate 332. It is also seen that the front wall burners 270, 272 project through openings 334 in the sidewalls 20, 22, and that ready access thereto is thus provided.

Expanded metal catwalks 336, 338 are hingedly connected to the top walls 280, 282, as by hinges 340 to provide more secure footing for the operator standing upon the compacting portion 94 of the screed assembly.

While there have been described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.

Claims

I claim:

1. Paving apparatus comprising: a material hopper having an inclined load-supporting wall and sidewalls, said walls respectively having lower extremities mutually defining a material discharge opening; gate means connected to said hopper for selectively opening and closing said opening including a plurality of side-by-side sections thereby to provide openings of various widths; first means for selectively moving one section alone between open and closed positions; second means for moving a plurality of adjacent sections between open and closed positions simultaneously between their open and closed positions; and a screed adjustably mounted on said rear wall and extending rearwardly therefrom, said first moving means comprising an elongated relatively flexible lifting member having one end attached to said one of said gate sections, said second moving means comprising a member connected to one of said gate sections in a manner to engage the adjacent sections when said one section is being moved into said closed position whereby movement of said one section into its closed position simultaneously moves the adjacent sections into their closed positions.

2. The apparatus of claim 1 further comprising at least one other elongated relatively flexible member having one end attached to a respective gate section, and means on said hopper for selectively engaging said flexible members thereby to hold said gate sections in said closed position thereof.

3. The apparatus of claim 1 wherein one of said walls is a rear wall, and further comprising a pair of wheels coaxially mounted adjacent the forward portion of said hopper, said screed normally supporting a substantial portion of the weight of said apparatus and the contents of said hopper, and further comprising means on said rear wall cooperatively engaging an abutment on said lifting member in said closed position of said one gate section plate member whereby further movement of said lifting member results in pivoting of said apparatus about said wheels thereby elevating said screed above said supporting surface.

4. Paving apparatus comprising: a material hopper having an inclined load-supporting wall and sidewalls, said walls respectively having lower extremities mutually defining a material discharge opening; means for heating said load-supporting wall; gate means connected to said hopper for selectively opening and closing said opening; a screed adjustably mounted on said rear wall and extending rearwardly therefrom; said load-supporting wall including a heating chamber therein, said heating means being positioned in said chamber, said heating means comprising at least one fluid fuel-burning nozzle positioned in said chamber; means for dividing said chamber into a plurality of sections, there being one of said nozzles respectively positioned in each of said chamber sections, each of said chamber sections having a baffle therein further dividing each of said chamber sections into lower and upper portions, the respective nozzle being positioned in a lower chamber portion and being remotely located from said dividing means, each of said upper chamber portions having at least one opening therein remotely located from said dividing means for exhausting combustion gases therefrom.

5. The apparatus of claim 4 wherein a wall joins said load-supporting wall to form a rear boundary of said chamber and the front boundary of said discharge opening, each of said nozzles being directed toward the interior surface of said wall.

6. Paving apparatus comprising: a material hopper having an inclined load-supporting wall and sidewalls, said walls respectively having lower extremities mutually defining a material discharge opening; means for heating said load-supporting wall; gate means connected to said hopper for selectively opening and closing said opening including a plurality of side-by-side sections thereby to provide openings of various widths; first means for selectively moving one section alone between open and closed positions; second means for simultaneously moving a plurality of selected adjacent sections between their open and closed positions; a screed adjustably mounted on said hopper and extending rearwardly therefrom; means extending forwardly from said hopper for selectively engaging a part of a conventional vehicle thereby to move said apparatus both in a forward and rearward direction; means for actuating said engaging means between an upper engaging position and a lower disengaged position, said actuating means including means for biasing said engaging means toward said upper engaging position; a bottom wall spaced below said load-supporting wall, and back and forward walls joining said other wall to said front wall and defining therewith and with the sidewalls of said hopper a first heating chamber, first means for dividing said first chamber into sections, second means for dividing each of said first chamber sections into upper and lower portions, said second means providing a connection between said portions, said load-supporting wall heating means comprising a fluid fuel-burning nozzle positioned in the lower portion of each of said first chamber sections remote from the connection between the respective portions, said bottom wall having openings therein respectively communicating with the upper portion of each of said first chamber sections remote from the connection between the respective portions for exhausting combustion gases therefrom whereby the combustion gases from each of said nozzles traverse both portions of the respective first chamber section; each of said gate means sections comprising a plate member mounted on one of said walls for pivotal movement between an upper closed position and a lower open position; said screed including a bottom material-compacting wall, a top wall spaced from said bottom wall, and respectively spaced back and forward walls and end walls mutually defining a second heating chamber, third means for dividing said second chamber into sections, fourth means for dividing each of said second chamber sections into portions which communicate adjacent one of said third dividing means and the respective end wall, a fluid-burning nozzle positioned in one portion of each of said second chamber sections remote from the communication between the respective portions, one of said forward and backwalls of said screed having openings therein respectively communicating with the other portion of each of said second chamber sections remote from the communication between the respective portions for exhausting combustion gases therefrom whereby the combustion gases from each of said last-named nozzles traverses both portions of the respective second chamber section, and a fluid fuel tank mounted on the rear surface of said backwall and coupled to all of said nozzles for supplying fuel thereto.