AU2003204271B2 - Improved method and apparatus for laying roadway materials - Google Patents

Description

- 1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicants: John Russell Sharpe and Alan Victor Sharpe and Ronald Douglas Sharpe Actual Inventors: John Russell Sharpe and Alan Victor Sharpe and Ronald Douglas Sharpe Address for Service: Baldwin Shelston Waters 60 MARGARET STREET SYDNEY NSW 2000 CCN: 3710000352 Invention Title: IMPROVED METHOD AND APPARATUS FOR LAYING ROADWAY MATERIALS Details of Associated Provisional Application No. PS2409 dated 20 May 2002 The following statement is a full description of this invention, including the best method of performing it known to us: File: 35186AUP01 -2 TECHNICAL FIELD This invention relates to the laying of roadway materials, and in particular to the laying of sections of roadway materials using a self-propelled road paving machine. The invention has particular application in the renewal of relatively narrow sections of 5 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. BACKGROUND OF THE INVENTION Road paving machines are commonly employed when a new section of roadway is being laid. Commercially available self-propelled road paving machines, such as those 10 marketed by BLAW-KNOX TM and INGERSOL RAND

TM

, 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 15 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. However in some situations, such as a road repair operation, the width of the 20 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. 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 25 vehicle, such as a BOBCATTM, is employed to transfer the asphalt from the truck to the repair site, the vehicle it can compress the spilled materialinto 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. 30 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 -3 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. 5 It is therefore 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. SUMMARY OF THE INVENTION To this end, the present invention provides a self-propelled road paving machine 10 including: a hopper for storing roadway material; a feed conveyor for transferring said roadway material from said hopper to a laterally extending spreading means; a levelling means located rearwardly of said spreading means for levelling said 15 roadway material; a diverting means located at the end of said feed conveyor and underneath said spreading means to prevent material from falling directly from said feed conveyor onto a road surface, said diverting means acting in conjunction with said spreading means to divert and deposit said roadway material to one side of the paving machine; 20 wherein the spreading means and the diverting means are mounted so as to permit a range of adjustment in position in the vertical plane relative to the screed. Preferably, the levelling means includes screed. Preferably, the spreading means comprises one or more rotatable augers located forwardly of the levelling means of the paving machine. More preferably, the spreading 25 means comprises a pair of rotatable augers located forwardly of the levelling means. Preferably, the pair of rotatable augers are configured so as to direct the roadway material in a common direction towards one side of the paving machine. Preferably, each auger is independently operable such that the direction of rotation of each auger can be selected by the operator. 30 Preferably, the spreading means and the diverting means are connected to a hydraulic ram configured so as to allow the operator to vary the height of the spreading means and the diverting means above the surface of the road.

-4 Preferably, the diverting means takes the form of a trough. In one embodiment the diverting means is a trough of substantially U-shaped in cross-section. In another embodiment the diverting means is a trough of substantially V shaped in cross-section. In a further embodiment the diverting means is shaped in the 5 form of a square or rectangular open channel which extends lengthwise beneath the spreading means. Preferably, the trough is formed in at least two sections so as to permit the trough to be opened. Preferably, a hydraulic ram is connected to one section of the trough to move the 10 section of the trough between open and closed positions. Preferably, the level of the feed conveyor on its return side is above the level of the augers. Preferably, the one or more augers are driven by means of variable speed reversible hydraulic motors. 15 Preferably, a shaft of each auger is supported at one end by a centre bearing and driven at each outer end by means of a chain drive located at the outer end of each auger shaft. Preferably, the trough assembly is demountable such that it can be attached and removed from the road paving machine. 20 In one form of the present invention it is possible for a conventional self propelled 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 25 invention it is possible to use a conventional paving machine to deposit sections of road materials in widths down to 100 mm or less. 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 30 roadway. By employing the present invention the time and labour requirements to deposit new sections of asphalt can be significantly reduced. Furthermore the incidence -5 of spillage is reduced, which in turn reduces the time and labour requirements associated with post-repair clean up operations.

-6 The present invention can be adapted to be used with most conventional self propelled road pavers, including machines marketed by BLAW-KNOX T M and INGERSOL RANDTM. BRIEF DESCRIPTION OF THE DRAWINGS 5 A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a side view of a typical self-propelled road paving machine with which the present invention is utilised and illustrating the flow of road material through the machine. 10 Fig. 2 is a simplified plan view of the road paving machine depicted in Fig. 1 illustrating the material flow path through the machine. 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. 15 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. Fig. 5 illustrates the paving guide shown in Figs. 4a, 4b, and 4c located in position with a road paving machine. Fig. 6 is a simplified plan view of the road paving machine with an alternative 20 arrangement of paving guides for depositing a section of road material to one side of the paving machine. 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. Fig. 8 is a simplified plan view of the road paving machine with a further 25 arrangement of paving guides for depositing a section of road material to one side of the paving machine. Fig. 9 illustrates a further preferred embodiment of a paving guide arrangement employed in conjunction with a road paving machine with an extendable screed. Fig. 10 is a simplified plan view of a road paving machine, illustrating a further 30 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.

-7 Fig. 11 is a simplified side view of the paving mechanism and paving guide arrangement shown in Fig. 10. 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; 5 Fig. 13 is a simplified side view which illustrates the trough in an open position; Fig. 14 is a simplified side view which illustrates the trough in a closed position; Figs. 15a and 15b illustrate the effect of raising the level of the feed conveyor to a level above that of the rotating augers; Fig. 16 illustrates a preferred drive arrangement and configuration for the 10 rotating augers; and Fig. 17 illustrates a plan view of the road paving machine with a further development according to the present invention. DESCRIPTION OF PREFERRED EMBODIMENTS Referring to Fig. 1, a typical commercially available self-propelled road paving 15 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 20 traverses from right to left as illustrated. In a preferred adaptation of the paving machine 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 25 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. Fig. 2 illustrates the flow of the asphalt material through the paving machine. In 30 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 of the machine the slat conveyors may be -8 replaced with belt or screw-type conveyors configured to feed the asphalt from the hopper section 3 to the augers 7. For example, screw-type conveyors may be preferred for minimising the incidence of spillage due to material carry back. Fig. 3 illustrates the location of the spreading augers 7 in relation to the screed 8 5 on a typical commercially available road paving machine. 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 10 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 15 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 20 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. In one embodiment, one or more paving guides 10 may be mounted on the 25 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. 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 30 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 -9 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 5 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. 10 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 15 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. Referring to Fig. 6 one embodiment of the present invention is depicted, wherein a diverter 18 is located beneath the auger 7. This arrangement is particularly suitable for repairing edges or "shoulders" of roadways. In one embodiment the diverter 18 takes 20 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 with a substantially "U" or "V" shaped cross-section. 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 25 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. 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 30 material and confine the deposition of the material to one side of the guide 10.

-10 Whilst the arrangement of Fig. 6 depicts the diverter 18 being used in conjunction with a paving guide 10, it is to be noted that the diverter 18 may be utilised either with or without one or more paving guides. Figs. 7a, 7b, and 7c depict an alternative embodiment of a paving guide which 5 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. Fig. 8 illustrates a plan view with a paving plate 19 in use. The lugs 20 contact the forward surface of the screed 8 of the paving machine. In this application feed 10 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. 15 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 20 whilst the wheels of the machine remain on the existing road surface. The guide means may take form of a diverter 18 as described with reference to Fig. 6. In a further preferred form of the invention, illustrated in Fig. 10, the diverter 18 extends 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 25 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. As illustrated in the embodiment of Fig. 11, the diverter 18 may take the form of 30 a rectangular open channel which is positioned beneath the augers 7 so as to prevent the road material from falling directly onto the road surface once it is discharged by the feed -11 conveyors 4a, 4b. The augers 7, in conjunction with the diverter 18, act to divert and deposit the roadway material to one side of the paving machine. Referring to Fig. 12, in another preferred embodiment the diverter 18 has a substantially U-shaped or V-shaped cross-section and extends lengthwise beneath the 5 augers 7. In a further development of the invention illustrated in Figs. 13 and 14, the augers 7 and diverter 18 may be mounted so as to permit a range of adjustment in position in the vertical plane relative to the screed 8. For example, in the embodiment depicted in Figs. 13 and 14 the augers and diverter are carried on a common assembly 10 which is mounted to the chassis of the road paving machine. The assembly is movable in the vertical plane with respect to the chassis. A hydraulic ram 22 is connected to the chassis and the assembly and by extending or retracting the ram 22 the operator can vary the height of the augers and diverter above the surface of the road. With particular reference to Figs. 13 and 14, the diverter 18 is preferably formed 15 in two longitudinally extending sections 18a, 18b so as to permit the diverter to be opened and closed. One section 18a of the trough is hingedly connected along one edge 24 so as to permit rotation between open and closed positions, whilst the second section 18b of the trough is fixed in position. A hydraulic ram 23 is connected to the hinged section 18a of the trough and by extending and retracting the ram 23 the trough can be 20 opened and closed. By configuring the trough such that it can be open and closed, it is possible to utilise road paving 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 in the repair of the shoulders of roadways. Figs. 15a and 15b illustrate a further preferred aspect of the present invention. 25 Fig. 15a illustrates the typical positional relationship between the slat conveyor 4 and the rotary auger 7 on a conventional road paving machine, wherein the level of the slat conveyor 4 on its return side lies below the upper level of the rotary auger 7. This can give rise to material build up in the diverter 18 and result in carry back of material as illustrated in Fig. 15a. In accordance with this aspect of the invention, illustrated in Fig. 30 15b, the return level of the slat conveyors 4 lies above the upper level of the rotary auger 7 so as to minimise the possibility of material carry back when the diverter trough is being used.

-12 In a further development, each of the augers 7 are driven by means of variable speed reversible hydraulic motors 25 via an enclosed drive chain 26 as illustrated in Figs. 13 and 14. By providing the augers 7 with independently controllable reversible drives, the 5 machine can operate in three different material delivery modes as illustrated in Fig. 16a. In delivery mode 1 material is diverted to opposing sides of the machine, whilst in delivery modes 2 and 3 the material is diverted to one side of the machine only. With reference to Fig. 16b, a further configuration of the rotating augers 7 is illustrated. In this configuration, the shaft of each auger is supported at one end by a 10 centre bearing 28 and driven at its outer end by means of drive chain and sprockets (not shown) located at the outer ends of each auger shaft. In a further development, illustrated in Fig. 17, the rotating augers 7 may be replaced by an alternative lateral spreading means, such as a conveyor belt. In this embodiment, a transversely extending belt conveyor 7 is located beneath the discharge 15 point of the slat conveyor 4 to catch the material and transfer it to one side of the paving machine. By providing the conveyor 7 with a reversible drive, material may be diverted to either side of the paving machine. It is to be noted that in this configuration it is not necessary to use a diverter beneath the conveyor 7. In one preferred embodiment, the diverter trough assembly may be demountable 20 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 25 demountable depending upon the application of the machine. In a further development of the road paving machine (not illustrated) the machine is provided with a grader blade which is mounted to the screed assembly and which acts to level the roadway material deposited outside the line of screed. Preferably, the grader blade is hingedly mounted to the screed assembly so that it can be rotated into position 30 when required and then rotated out of position when not in use. 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 -13 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. From the foregoing detailed description, it will be evident that there are a number 5 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.

Claims (18)

1. A self-propelled road paving machine including: a hopper for storing roadway material; a feed conveyor for transferring said roadway material from said hopper to a 5 laterally extending spreading means; a levelling means located rearwardly of said spreading means for levelling said roadway material; a diverting means located at the end of said feed conveyor and underneath said spreading means to prevent material from falling directly from said feed conveyor onto a 10 road surface, said diverting means acting in conjunction with said spreading means to divert and deposit said roadway material to one side of the paving machine, wherein said spreading means and said diverting means are mounted so as to permit a range of adjustment in position in the vertical plane relative to said screed.

2. The road paving machine as claimed in claim 1 wherein said levelling means 15 includes screed.

3. The road paving machine as claimed in claim 1 or 2 wherein said spreading means comprises one or more rotatable augers located forwardly of the levelling means of the paving machine.

4. The road paving machine as claimed in claim 3 wherein said spreading means 20 comprises a pair of rotatable augers located forwardly of the levelling means.

5. The road paving machine as claimed in claim 4 wherein said pair of rotatable augers are configured so as to direct said roadway material in a common direction towards one side of the paving machine.

6. The road paving machine as claimed in claim 4 or 5 wherein each auger is 25 independently operable such that the direction of rotation of each auger can be selected by the operator.

7. The road paving machine as claimed in any one of claims I to 6 wherein said spreading means and said diverting means are connected to a hydraulic ram configured so as to allow the operator to vary the height of said spreading means and said diverting 30 means above the surface of the road. -15

8. The road paving machine as claimed in any one of claims 1 to 7 wherein said diverting means is a trough formed in at least two sections so as to permit the trough to be opened.

9. The road paving machine as claimed in claim 8 wherein a hydraulic ram is 5 connected to one section of the trough to move said section of the trough between open and closed positions.

10. The road paving machine as claimed in any one of claims I to 9 wherein said diverting means is a trough of substantially U-shaped in cross-section.

11. The road paving machine as claimed in any one of claims I to 9 wherein said 10 diverting means is a trough of substantially V-shaped in cross-section.

12. The road paving machine as claimed in any one of claims I to 9 wherein said diverting means is shaped in the form of a square or rectangular open channel which extends lengthwise beneath the spreading means.

13. The road paving machine as claimed in any one of claims I to 12 wherein the 15 level of the feed conveyor on its return side is above the level of the augers.

14. The road paving machine as claimed in claim 3 wherein said one or more augers are driven by means of variable speed reversible hydraulic motors.

15. The road paving machine as claimed in claim 3 wherein a shaft of each auger is supported at one end by a centre bearing and driven at each outer end by means of a 20 chain drive located at the outer end of each auger shaft.

16. The road paving machine as claimed in any one of claims I to 15 wherein said diverting means is demountable such that it can be attached and removed from the road paving machine.

17. The road paving machine as claimed in any one of claims 1 to 16 wherein said 25 feed conveyor is a slat-type conveyor.

18. A road paving machine substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples. 30