Method and apparatus for laying roadway materials

[0001] This is a Continuation-in-Part application of application Ser. No. 09/587,843 filed on Jun. 6, 2000, which is a Continuation-in-Part application of application Ser. No. 09/029,965, now U.S. Pat. No. 6,086,287.

[0002] This invention relates to the laying of roadway materials, and in particular to the laying of sections of roadway materials using a road paving machine. The invention has particular application in the renewal of relatively narrow sections of damaged or deteriorated asphalt in an existing roadway, including the repair of edge sections of roadway. The invention may also be utilised in road widening applications.

[0003] Road paving machines are commonly employed when a new section of roadway is being laid. Commercially available road paving machines, such as those marketed by BLAW-KNOX and INGERSOL RAND, are typically designed for laying sections of hot-mix asphalt in widths of 2400 mm and greater. In general, such machines require a full screed of asphalt material in order to ensure the correct functioning of the controls which determine the height of the new layer of asphalt. Whilst there are a number of specialised road paving machines designed to lay narrower sections of asphalt, even such specialised paving equipment cannot lay asphalt in widths of less than approximately 1200 mm. Furthermore, for commercial reasons it is undesirable to purchase a specialised road paving machine due to its relatively limited application and comparatively high cost.

[0004] However in some situations, such as a road repair operation, the width of the section of roadway to be laid is often less than 2400 mm, and frequently of the order of 1000 mm or less. Such situations can prove to be highly labour intensive, and may require labourers to manually deposit and spread the asphalt in the trench.

[0005] During a manual road repair operation spillage of asphalt material can occur whilst transferring the asphalt from a truck to the trench in the road. If a front-end loader vehicle, such as a BOBCAT, is employed to transfer the asphalt from the truck to the repair site, the vehicle it can compress the spilled material into the road surface thereby making it difficult to remove after completion of the repair operation. It may then be necessary for labourers to scrape and rake the spilled material from the road surface and this clean up operation can be a time and labour intensive task.

[0006] Furthermore, the process of transferring the asphalt material from the truck to the repair site demands both time and labour. Typically, one person is required to operate a vehicle to transfer the replacement asphalt from the truck to the repair site, a further person is required to operate the truck, and an additional person may be required to ensure traffic control whilst the asphalt is transferred between the truck and the repair site. If the length of asphalt to be laid is extensive it may be necessary to move the location of the truck and result in further areas of spillage.

[0007] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0008] A first aspect of the present invention provides a method of depositing roadway material using a road paving machine, said road paving machine including a hopper for storing roadway material, a longitudinally extending feed conveyor for transferring said roadway material from said hopper to a laterally extending auger assembly including an auger, wherein said method includes locating a trough at the end of the feed conveyor of the paving machine and underneath said auger to prevent said roadway material from falling directly from said feed conveyor onto a road surface, said trough acting in conjunction with said auger to divert and deposit the roadway material to one side of the paving machine.

[0009] Preferably, the trough is substantially U-shaped or V-shaped in cross-section.

[0010] Preferably, the auger is movable in a vertical plane so as to vary the height of the auger above the road surface and the trough is attached to the auger assembly so as to move vertically with the auger.

[0011] Preferably, a spacer means is used to control the height of the screed above the road bed. Preferably, the spacer means is of a height which allows for compaction of the deposited material.

[0012] A second aspect of the present invention provides a road paving machine comprising a self propelled vehicle including:

[0013] a hopper for storing roadway material;

[0014] a feed conveyor for transferring said roadway material from said hopper to a laterally extending auger; and

[0015] a trough located at the end of the feed conveyor and underneath said auger to prevent material from falling directly from said feed conveyor onto a road surface, said trough acting in conjunction with said auger to divert and deposit the roadway material to one side of the paving machine.

[0016] Preferably, the trough is located at the end of the feed conveyor of the paving machine and acts to prevent material from falling directly from the feed conveyor onto the road surface, the trough acting in conjunction with the spreading means of the paving machine to divert and deposit the material to one side of the paving machine.

[0017] Preferably, the trough is mounted on the road paving machine and moves with the paving machine.

[0018] Alternatively, the trough may be shaped in the form of a square or rectangular open channel which extends lengthwise beneath the spreading means of the paving machine.

[0019] Preferably, the method of the present invention further includes the step of locating a second guide means underneath said spreading means so as to define a limit for the material deposited by the road paving machine and thereby confine the deposition of the material to one side of said second guide means.

[0020] The method of the present invention can be utilised in the deposition of a road surface material, such as a hot-mix asphalt. Alternatively the method can be utilised to deposit a road base material, such as blue metal aggregate or the like.

[0021] Advantageously, the present invention provides an improved method for laying a relatively narrow section of roadway material, such as a road base material, asphalt, soil or any other material used for roadways which reduces the time and labour requirements of the present methods. More particularly, the present invention enables the laying a relatively narrow section of roadway material, such as a road base material, asphalt, soil or any other material suitable for laying roadways, with a conventional road paving machine.

[0022] In one form of the present invention it is possible for a conventional road paving machine to be utilised to deposit sections of road materials in widths which are less than the normal working width of the paving machine. Road paving machines are typically designed for laying sections of road materials in widths of 2400 mm and greater. However by using the method and apparatus of the present invention it is possible to use a conventional paving machine to deposit sections of road materials in widths down to 100 mm or less.

[0023] In one preferred form of the invention the method further includes the use of one or more spacer means to determine the height of deposition of the road material. The height of the spacer means should be such as to allow for compaction of the deposited material. Preferably the spacer means acts to determine the height of the screed surface above the road surface.

[0024] In one preferred application the present invention can be employed in repairing an extended, relatively narrow, section of roadway. Preferably, the present invention can be employed to repair the edge or shoulder of a roadway, or to widen a section of roadway.

[0025] By employing the present invention in the repair of relatively narrow sections of roadway the time and labour requirements to deposit new sections of asphalt are significantly reduced. Furthermore the incidence of spillage is reduced, which in turn reduces the time and labour requirements associated with post-repair clean up operations.

[0026] The method and apparatus of the present invention can be adapted to be used with most conventional road pavers, including machines marketed by BLAW-KNOX and INGERSOL RAND.

[0027] A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0028] FIG. 1 is a side view of a typical road paving machine with which the present invention is utilised and illustrating the flow of road material through the machine.

[0029] FIG. 2 is a simplified plan view of the road paving machine depicted in FIG. 1 illustrating the material flow path through the machine.

[0030] FIG. 3 is a simplified side view of the paving mechanism of a typical road paving machine illustrating the relationship between the augers and the screed of the paving mechanism.

[0031] FIGS. 4a, 4b and 4c illustrate side, plan and perspective views respectively of one preferred embodiment of a paving guide which may be utilised in the present invention.

[0032] FIG. 5 illustrates the paving guide shown in FIGS. 4a, 4b, and 4c located in position with a road paving machine.

[0033] FIG. 6 is a simplified plan view of the road paving machine with an alternative arrangement of paving guides for depositing a section of road material to one side of the paving machine.

[0034] FIGS. 7a, 7b and 7c illustrate side, plan and perspective views respectively of a further preferred embodiment of a paving guide utilised in the present invention.

[0035] FIG. 8 is a simplified plan view of the road paving machine with a further arrangement of paving guides for depositing a section of road material to one side of the paving machine.

[0036] FIG. 9 illustrates a further preferred embodiment of a paving guide arrangement employed in conjunction with a road paving machine with an extendable screed.

[0037] FIG. 10 is a simplified plan view of a road paving machine, illustrating a further preferred embodiment of a paving guide arrangement in the form of a trough positioned beneath the augers of the road paving machine to divert and deposit material to one side of the paving machine.

[0038] FIG. 11 is a simplified side view of the paving mechanism and paving guide arrangement shown in FIG. 10.

[0039] FIG. 12 is a simplified side view of the paving mechanism and a diverter trough of a substantially U-shaped or V-shaped cross-section;

[0040] FIG. 13 is a simplified side view which illustrates the diverter trough in an open position;

[0041] FIG. 14 is a simplified side view which illustrates the diverter trough in a closed position;

[0042] FIGS. 11a and 15b illustrate the effect of raising the level of the feed conveyor to a level above that of the rotating augers;

[0043] FIGS. 16a and 16b illustrate a preferred drive arrangement and configuration for the rotating augers; and

[0044] FIG. 17 illustrates a plan view of the road paving machine with a further development according to the present invention.

[0045] Referring to FIG. 1, a typical commercially available road paving machine 1 is depicted. Hot mix asphalt 2 is held in a hopper section 3 of the machine and is fed via feed conveyors 4 towards the rear of the machine where it is deposited onto the roadway 5. The deposited material 6 is spread laterally by means of rotating augers 7 located forwardly of the screed section 8 of the paving machine. A layer of asphalt 9 of relatively uniform height is left on the roadway as the paving machine traverses from right to left as illustrated. In a preferred adaptation of the paving machine provided by the present invention the drive wheels of the machine may be mounted on hydraulic rams in order to vary the ground clearance of the machine. Preferably the wheels of the machine may be mounted on independent hydraulic rams so that the paving machine can be maintained at a horizontal level whilst negotiating trenches. Referring to FIG. 1, the extended position of the drive wheel of the machine when negotiating a trench is illustrated in broken line. The machine may also be provided with a skid plate at the lower front end of the machine which acts to guide the steering wheels of the paving machine out of a trench.

[0046] FIG. 2 illustrates the flow of the asphalt material through the paving machine. In the machine depicted there are left and-right feed conveyors 4a, 4b which feed the asphalt from the hopper section 3. The feed conveyors 4a, 4b are slat-type conveyors. However in an alternative arrangement the slat conveyors may be replaced with belt or screw-type conveyors configured to feed the asphalt from the hopper section 3 to the augers 7. The use of screw-type conveyors may be preferred for minimising the incidence of spillage due to material carry back.

[0047] FIG. 3 illustrates the location of the spreading augers 7 in relation to the screed 8 on a typical commercially available road paving machine.

[0048] FIGS. 4a, 4b, and 4c depict one embodiment of a paving guide which may be utilised in the present invention. The paving guide 10 includes a sole plate 11 which rests upon and moves along the road surface. An upwardly extending wall member 12 is provided at a front portion of the paving guide to restrict the deposition of road material to an area lying to one side of the guide. It is preferred that the wall member 12 extends approximately 50 mm above the road surface so as to provide an adequate barrier for the deposited material whilst also avoiding fouling of the auger mechanism of the paving machine. The paving guide 10 also includes an upwardly projecting member or lug 13 which is adapted to contact or engage with the paving mechanism of the paving machine so that the paving guide 10 is pushed along the roadway as the machine traverses the section of road to be repaired. The wall member 12 is located adjacent a longitudinal outer edge 14 of the sole plate and extends forwardly of the lug 13. The forward end 15 of the paving guide is turned upwardly so as to assist the guide in riding over any irregularities that may be encountered in the road surface. The paving guide may further include an adjustable connection means 13a for connecting the guide to the paving mechanism. The connection means preferably comprises a threaded rod member 13a to connect the paving guide to the screed of the paving machine. The rod member 13a is supported by a gusset plate 13b.

[0049] In one embodiment, one or more paving guides 10 may be mounted on the paving machine and be adjustable in position. For example, it is envisaged that one or more paving guides 10 may be connected to the screed and adjustable with respect to lateral positioning.

[0050] FIG. 5 illustrates a paving guide 10 located in position with the paving machine. The lug member 13 of the paving guide contacts or is connected to a forward surface of the screed 8 of the paving mechanism. In this way the paving guide 10 is pushed along the roadway 5 as the paving machine traverses the section of road to be repaired. In an alternative arrangement the paving guide 10 may be connected to the screed by a mechanical connection. A spacer means 15 is employed between the sole plate 11 of the paving guide and the screed plate 16 of the screed 8. The spacer means is used to control the height of the deposition of uncompacted asphalt in relation to the level of the existing roadway and also protects the screed plate from being damaged. The spacer 15 can be made from suitable material, with timber being preferred. A range of spacers of varying heights can be used so as to accommodate for filling trenches of different depths and to allow for the compaction of the asphalt material after it has been deposited. It is also possible for the spacer means to take the form of an adjustable means so as to enable the height of the deposited material to be controlled between a range of heights. In one application of the present invention replacement asphalt is deposited in a trench to a height above that of the level of the existing roadway in order to accommodate for compaction of the material. Hot mix asphalt material can typically experience a compaction ratio of approximately 20% to 25%. Therefore, for a trench depth of 25 mm the allowance for compaction is typically an additional 5 mm, whilst for a 150 mm depth of trench the additional allowance for compaction is a further 30 mm. By changing the height of the spacers employed different depths of trench can be accommodated.

[0051] Referring to FIG. 6 a further embodiment of the present invention is depicted. In this arrangement the guide means for the roadway material takes the form of a cowl or diverter 18. This arrangement is particularly suitable for repairing edges or shoulders of roadways. In one embodiment the diverter 18 takes the form of a plate which is located at the end of the feed conveyor 4 and beneath the auger 7. In an alternative preferred embodiment the diverter 18 takes the form of a trough which is positioned beneath the auger 7 and shaped around the auger. The diverter 18 may be shaped in the form of a square or rectangular open channel or may be formed in a substantially U or V shape. The diverter 18 acts to prevent material from failing directly from the feed conveyor 4 onto the road surface. The auger 7, in conjunction with diverter 18, acts to divert and deposit material to one side of the paving machine. In the application depicted, feed conveyor 4a is active, whilst feed conveyor 4b is shut off. In this way asphalt can be deposited to one side of the paving machine as is desirable when repairing an edge or shoulder of a roadway.

[0052] In FIG. 6 a paving guide 10 is used in conjunction with the diverter 18, with the guide 10 acting to provide an edge surface defining the limit for the deposited material and confine the deposition of the material to one side of the guide 10. However whilst the arrangement of FIG. 6 depicts the cowl or diverter 18 being used in conjunction with a paving guide 10, it is to be noted that the cowl or diverter 18 may be utilised either with or without one or more paving guides.

[0053] FIGS. 7a, 7b, and 7c depict an alternative embodiment of a paving guide which may be utilised with the present invention. In this embodiment the guide takes the form of a plate 19 which includes upwardly projecting lugs 20 adapted to contact with the paving machine so that the plate is moved along the roadway with the machine.

[0054] FIG. 8 illustrates a plan view with the paving plate 19 in use. The lugs 20 contact the forward surface of the screed 8 of the paving machine. In this application feed conveyor 4b is either inoperative or blanked off. The road material is deposited via feed conveyor 4a onto the paving plate. The auger 7 then acts to spread the material laterally out to the side of the machine and beyond the outer edge 21 of the paving plate 19. In this way road material is prevented from being deposited in the area covered by the paving plate.

[0055] Referring to FIG. 9, it is possible to utilise the paving guide arrangements described in conjunction with a road paving machine with an extendable screed. This arrangement is particularly applicable when repairing the edge or shoulder of a roadway where it is desired to keep the wheels of the paving machine on the existing road surface. As illustrated, road material is diverted to an outer side of the paving machine whilst the wheels of the machine remain on the existing road surface. The guide means may take form of a cowl or diverter 18 as described with reference to FIG. 7. In a particularly preferred form the guide means takes the form of a trough which is positioned beneath the auger 7 and shaped around the auger.

[0056] In a further form of the invention, illustrated in FIG. 10, the cowl or diverter 18 may extend under substantially the entire length of the augers 7. Additionally, the augers 7 may be configured so as to direct material in a common direction towards one side of the paving machine. For example, each auger may be independently operable such that the direction of rotation of each auger can be selected by the operator. In this way, it is possible for the operator to have both augers driving material in the same direction as is illustrated in FIG. 10.

[0057] Referring to the embodiment in FIG. 11, the cowl or diverter 18 may take the form of a rectangular open channel which is positioned underneath the augers 7 so as to prevent the road material from falling directly onto the road surface once it is discharged by the feed conveyors 4a, 4b.

[0058] Referring to FIG. 12, in one preferred embodiment the cowl or diverter trough 18 has a substantially U-shaped or V-shaped cross-section as illustrated.

[0059] In a preferred embodiment of the invention the auger assembly comprising the auger 7 is movable in a vertical plane so as to vary its height above the road surface 5. The cowl or diverter trough 18 is connected to the auger assembly so as to move vertically with the auger. In this development of the invention, illustrated in FIGS. 13 and 14, the augers 7 and diverter 18 are mounted so as to permit a range of vertical adjustment relative to the screed 8. In this embodiment, the augers and diverter are connected to a hydraulic ram 22 configured so as to allow the operator to vary the height of the augers and diverter above the surface of the road 5. In FIG. 13 the hydraulic ram 22 is retracted, thereby holding the auger assembly and trough well above the level of the road surface 5. In FIG. 14 the hydraulic ram 22 is extended thereby bringing the auger assembly and trough into a position adjacent the road surface.

[0060] With particular reference to FIGS. 13 and 14, the cowl or diverter trough 18 may be formed of two sections 18a, 18b so as to permit the trough to be opened as depicted in FIG. 13. A hydraulic ram 23 is connected to one section 18a of the trough. The trough section 18a is hingedly connected along one edge 24 so as to permit rotation between open and closed positions as shown in FIGS. 13 and 14 respectively. In order to open the trough, the hydraulic ram 23 is retracted as shown in FIG. 13. To close the trough, the hydraulic ram 23 is extended so as to bring sections 18a and 18b together. By configuring the trough such that it can move between open and closed positions, it is possible to use the machine for normal road paving applications and then, by closing the trough, use the machine to divert road paving material to one side of the machine such as when repairing the shoulders of roadways.

[0061] In a further development, the augers 7 are driven by one or more variable speed, reversible motors 25. The motors 25 may be electrically or hydraulically driven, although hydraulic motors are preferred. A chain or belt drive 26 operatively connects the motors 25 to the augers 7 so as to transfer drive to the auger.

[0062] FIGS. 15a and 15b illustrate a further preferred aspect of the present invention. In FIG. 15a, the level of the return side of the conveyor 4 lies below the top of the auger 7. It has been found that this results in a build-up of material in the trough 18 and subsequent carry back of the material on the return side of the conveyor. In accordance with this aspect of the invention as depicted in FIG. 15b, the level of the return side of the conveyor 4 is above the level of the rotary augers 7 so as to minimise the possibility of material carry back when the diverter trough 18 is being used. Typically, the distance 27 between the top of the auger and the return side of the conveyor is in the range of 10 to 50 mm.

[0063] With reference to FIGS. 16a and 16b, a further configuration of the rotating augers 7 is illustrated. The auger assembly comprises a pair of aligned augers 7a, 7b, each on a separate shaft. In this configuration, each auger shaft is supported at one end by a centre bearing 28 and driven at each outer end by means of drive chain and sprockets located at the outer ends of each auger shaft. Each auger shaft is driven by a reversible motor so that the augers may be rotated either in the same or opposing directions. This enables the operator to operate the augers so as to transfer material to opposing sides of the road paving machine (delivery mode 1), or to only one side of the machine (delivery modes 2 and 3) as illustrated in FIG. 16a.

[0064] In a further development illustrated in FIG. 17, the rotating augers 7 may be replaced by an alternative conveying means, such as a conveyor belt. In a further development, the augers 7 may comprise a pair of parallel, laterally extending augers.

[0065] In one preferred embodiment, the diverter trough assembly may be demountable such that it can be attached and removed from the road paving machine depending upon its application. For example, if the machine is to be used in the repair of the edges of roadways, the diverter assembly can be attached to the machine. When the machine returns to normal road paving applications, the diverter assembly can be removed. In addition to the diverter being demountable, the rotary auger assembly may also be demountable depending upon the application of the machine.

[0066] Thus, it can be appreciated that the present invention provides a method and apparatus for depositing a relatively narrow section of roadway material, such as a road base material, asphalt or soil, which enables the use of a conventional road paving machine and which in turn affords a significant reduction in time and labour requirements in depositing the roadway material.

[0067] From the foregoing detailed description, it will be evident that there are a number of changes, adaptations and modifications of the present invention which come within the province of those skilled in the art. However, it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof as limited solely by claims appended hereto.