Patent Application
20110182664
The invention relates to a method and apparatus for deploying sealant onto a road to seal cracks in the road.
Road maintenance is an on-going activity to ensure roads remain suitable for carrying traffic. The processes and equipment involved in maintenance depend on the nature of damage to the road surface. For example, where a road surface has suffered delamination or fatigue, it may be necessary to remove the damaged sections of roads and replacing with an asphalt patch.
Cracks are typically narrow and very long, and therefore make up a relatively small proportion of the road surface. Removal and replacement of a section of road in which the only damage is a crack is not economical. Furthermore, the time and the size of the equipment interfere with flow of traffic, often causes excessive traffic disruption. Cracks may branch and increase in size to the extent that the section of road needs to be replaced. However, in most cases, cracks can effectively be repaired with a bitumen-based sealant that fills the crack and prevents further damage.
It is known to repair cracks using a vehicle that carries sealant, which is deployed rearwardly from the vehicle to a hand held tool controlled by a worker walking behind the vehicle. The vehicle travels forward slowly so that the process is substantially continuous.
A worker trailing the repair vehicle is exposed to on-coming traffic and the risk that stray traffic could accidentally drive into the worker and the repair vehicle. Although the risk is small, the consequences of such an event occurring can be fatal.
The present invention provides a road crack repair system for mounting on a vehicle, the system comprising:
a sealant applicator that is positionable in front of the vehicle, the sealant applicator having a sealant outlet for discharging a molten sealant product above a crack in a road surface, and a trowel that is adjacent the sealant outlet and is arranged to contact the road surface and spread sealant product into and over the crack;
a vessel within which to store a molten sealant product, and a conduit for delivering sealant product from the vessel to the sealant outlet;
a support that is arranged to support the applicator in front of the vehicle with the trowel in contact with the road surface; and
a control system that is operable by an operator to displace the applicator along road surface to follow a crack with advancement of the vehicle in a forward direction.
In certain embodiments, the applicator has a leading end and a trailing end, the sealant outlet is positioned forwardly of the trailing end, and at least part of the trowel is positioned behind the sealant outlet such that as the applicator is moved forwardly with the leading end encountering an exposed crack first, sealant is discharged from the outlet in front of the trowel.
In some embodiments, the trowel is in the form of a ring, and, in use, the sealant outlet discharges sealant product into the ring to form a reservoir of molten sealant product that is then spread into and over the crack by displacement of the ring.
The applicator can include a reservoir heater for heating sealant within the reservoir.
In some embodiments, the heater in the form of a resistive heating element that extends circumferentially around the ring.
The applicator may include one or more air jets that each direct an air stream in front of the leading end of the trowel for blowing loose debris out of the crack.
The applicator can be movable transversely and longitudinally with respect to the vehicle, and can also be rotatable, such that the applicator can be moved along a crack and orientated with its leading end toward the section of crack to be sealed.
In some embodiments, the trowel can be displaced along an axis that is approximately perpendicular to the road surface when the trowel is in contact with the road surface to accommodate variations in the road height.
In some embodiments, the trowel can be pivoted on one or more axes that are approximately parallel to the road surface when the trowel is in contact with the road surface to accommodate variations in the road pitch.
In embodiments in which the trowel is in the form of a ring, the applicator may include a flange that projects radially outwardly from the ring on at least the leading end, the flange acts as a skid to facilitate movement of the ring and accommodate variations in the road pitch and/or height.
The support may be in the form of a frame on which the applicator is mounted, the frame being mountable to the front of the vehicle.
The frame can have a transverse rail on which the applicator is mounted; and a pair of longitudinal arms that support the transverse rail and, in use, extend forwardly from the vehicle.
The road crack repair system can further comprise a first actuator for displacing the applicator in a transverse direction with respect to the vehicle, and one or more second actuators for displacing the applicator longitudinally with respect to the vehicle.
In embodiments in which the system includes the above described frame, the first actuator is arranged to displaces the applicator along the transverse rail. Furthermore in embodiments in which the system includes the above described frame, the second actuator is arranged to displace the transverse rail longitudinally along the longitudinal arms.
The road crack repair system may further comprise a third actuator for rotating the applicator about an axis that is approximately perpendicular to the road surface when the trowel is in contact with a road surface. In embodiments in which the system includes the above described frame, the third actuator is arranged to rotate the applicator about a plurality of axes that are all approximately perpendicular to the transverse rail.
The road crack repair system may further comprise a fourth actuator for displacing the trowel along an axis that is approximately perpendicular to the road surface when the trowel is in contact with a road surface. In embodiments in which the system includes the above described frame, the fourth actuator is arranged to displace the trowel relative to the transverse rail in a plurality of planes that are perpendicular to transverse rail.
The road crack repair system may further comprises a fifth actuator for rotating the applicator about an axis that is parallel to the transverse rail. In embodiments in which the system includes the above described frame, the fifth actuator may be arranged to rotate the transverse rail and the applicator relative to the longitudinal arms.
The longitudinal arms can be pivotally mounted to the vehicle, such that the frame is movable between a deployed position, in which the longitudinal arms are generally horizontal, and a stowed position, in which the longitudinal arms are generally vertical.
The frame can further comprise a mounting beam that is mountable on the vehicle, and includes pivots on which proximal ends of the longitudinal arms are mounted.
The road crack repair system can further comprise a retraction device for moving the frame between the deployed and stowed positions. In certain embodiments, the retraction device is in the form of a cable that has one end attached to the frame, and a cable winch mounted directly or indirectly on the vehicle.
The road crack repair system can further comprise a boom that extends over the cabin of the vehicle in the forward direction of the vehicle, the boom supporting the conduit.
In embodiments in which the system comprises a retraction device that is in the form of a cable, the boom also supports the cable winch.
In some embodiments, the frame further comprises a cross beam that extends between the distal ends of the longitudinal arms.
The cross beam may be provided with one or more swivel caster wheels that, when the frame is in the deployed position, can contact the road surface and provide support to the frame. Preferably, the caster wheels depend from the cross beam.
In certain embodiments, the road crack repair system further comprises a surfactant discharge system that includes one or more spray nozzles that, in use, each spray a surfactant onto one of the road surface in front of one of the vehicle's tyres, or directly onto the tyres.
The control system can be operable to control any one or more of:
Alternatively or additionally, the control system can be operable to control any one or more of:
The control system may also include a joystick that is operable by an operator to displace the applicator in transverse and longitudinal directions relative to the vehicle.
In certain embodiments, the control system is also operable to automatically rotate the applicator with displacement of the applicator relative to the vehicle such that the leading end of the applicator is orientated in the same direction as the displacement of the applicator.
The present invention may also provide a vehicle comprising the road crack repair system described previously.
The present invention may also provide a method of repairing a crack in a road surface, the method comprising:
In order that the invention may be more easily understood, embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:
In this embodiment, the vehicle 10 is a tray-truck type vehicle, having a tray 12 supported on the vehicle chassis behind the driver's cabin 14. The system 20 includes a vessel 22 (shown in
The repair system 20 has a support that is arranged to support the applicator 50 in front of the vehicle 10. In this embodiment, the support is in the form of a frame 40. The system includes a control system (not shown) that is operable by an operator to displace the applicator 50 along road surface to follow a crack with advancement of the vehicle in a forward direction. In use, a conduit 24 delivers sealant product from the vessel 22 forwardly of the vehicle 10 to the applicator 50 for application into and over the crack.
The system 20 mounted to the vehicle 10 in the manner described enables sealing of road cracks with the applicator being positioned in front of the vehicle, and thus in the path of the vehicle. An operator can operate the system 20 from within the cabin 16, and thus not be exposed to traffic and other hazards.
As shown in
The frame 40 includes a transverse rail 42 on which the applicator 50 is mounted, and a pair of longitudinal arms 44 that support the transverse rail 42. As shown in
The applicator 50 can be movable transversely and longitudinally with respect to the vehicle, and can also be rotatable, such that the applicator can be moved along a crack to be sealed. This facilitates repairing of road cracks by moving the applicator 50 to along the crack as the vehicle progresses forward. As will be appreciated, road cracks are often serpentine, and can branch off into separate cracks.
In this particular embodiment, the applicator 50 is movable along the transverse rail 42 in a direction that is transverse to the vehicle 10. Furthermore, the transverse rail 42 is movable along the longitudinal arms 44, such that the applicator is movable in a direction that is longitudinal to the vehicle 10 (and thus perpendicular to the transverse rail 42). Thus, the applicator 50 is able to be moved to any location that is between the pair of longitudinal arms 44.
The road crack repair system 10 has a first actuator for displacing the applicator 50 in the transverse direction. In this particular embodiment, the first actuator is in the form of a chain drive 38a. The system 10 also has one or more second actuators for displacing the applicator 50 in the longitudinal direction. In this particular embodiment, the second actuator is in the form of a chain drive 38b. The chain drives 38a, 38b are shown in
The applicator 50 can be rotated with the transverse rail 42 on the longitudinal arms 44. As can be appreciated from the Figures, the applicator 50 is relatively tall and narrow. When the frame 50 is in the stowed position, the applicator 50 is rotated such that it lies with its lengthwise direction aligned with the longitudinal arms 44. This provides for compact stowage of the applicator 50. However, when the frame 40 is in the deployed position for use in road repair activities, the applicator 50 needs to be rotated such that the applicator 50 can contact the road surface, as will be discussed in further detail subsequently. The system 20 includes an actuator to rotate the applicator 50 such that its lengthwise direction is perpendicular to the longitudinal arms 44. In this embodiment, the actuator is in the form of a chain drive 38c, which is shown in
The road crack repair system 20 has a boom 30 that extends over the cabin 14 of the vehicle 10. The boom 30 supports the conduit 24 above the cabin 14 and forwardly out over the frame. Supporting the conduit 24 on the boom 30 assists in minimizing the possibility of damage to the conduit 24. However, it will be appreciated that in some alternative embodiments, the conduit could be supported beneath the floor of the vehicle, or to the side of the vehicle.
A retraction device is provided to move the frame 40 between the stowed and deployed positions. In this embodiment, the retraction device is in the form of a cable 32a that has one end attached to the frame, and a cable winch 32b mounted directly or indirectly on the vehicle 10. In this embodiment, the cable winch 32b is mounted on the boom 30.
The frame 40 further has a mounting beam 46 that is mounted to the vehicle 10. The longitudinal arms 44 are pivotally mounted to the mounting beam 46. Furthermore, a cross beam 48 extends between the distal ends of the longitudinal arms 44 to provide rigidity to the longitudinal arms 44.
The cross beam 48 has a pair of swivel caster wheels 49 that, when the frame 40 is in the deployed position, can contact the road surface and provide support to the frame 40. As shown in
As will be appreciated, the use of the frame 40 provides for safety of pedestrians and property. The applicator 50 can only be moved within the boundary of the frame 40 (defined by the vehicle 10, the longitudinal arms 44, and the cross beam 48). Thus, it is unlikely that a pedestrian could stray into the path of the moving applicator 50.
As described previously, when the frame 40 is in the deployed position for use in road repair activities, part of the applicator 50 contacts the road surface. Detail of the applicator 50 is illustrated in
The applicator 50 has a leading end L and a trailing end T. The sealant outlet 52 is positioned forwardly of the trailing end T, and part of the trowel 54 is positioned behind the sealant outlet 52. In this way, as the applicator is moved forwardly with the leading end L encountering an exposed crack first, sealant is discharged from the outlet 52 in front of the trowel 54.
As is most evident from
A pair of air jets 58 that each direct an air stream are provided to the applicator 50 in front of the leading end L. The air jets blow loose debris out of the crack immediately before sealant product is applied. This reduces the chance of the sealant product being lifted from the crack after application.
As described previously, the applicator 50 is movable transversely and longitudinally with respect to the vehicle. In addition, the applicator 50 is rotatable, such that the applicator 50 can be moved along a crack and orientated with its leading end L toward the section of crack to be sealed. To this end, an actuator is provided to rotate the applicator 50 about an axis that is approximately perpendicular to the road surface when the trowel 54 is in contact with a road surface. This actuator can be in the form of a belt drive 38d. Since the applicator 50 is supported on the transverse rail 42, which is rotatable and displaceable relative to the longitudinal arms 44, the belt drive 38d can rotate the applicator 50 about a plurality of axes that are all approximately perpendicular to the transverse rail 42.
The road crack repair system 10 may has an actuator for displacing the trowel 54 along an axis that is approximately perpendicular to the road surface when the trowel 54 is in contact with a road surface. In the Figures, this actuator is obscured by the frame components and the applicator. In
The applicator 50 includes a flange 59 that projects radially outwardly from the trowel 54 on at least the leading end L, the flange 59 acts as a skid to facilitate movement of the trowel 54 over the road surface and accommodate variations in the road pitch and/or height. The flange 59 extends around approximately three quarters of the circumference of the trowel 54, and thus provides a skid to forwards and sidewards movement of the trowel 54 over the road surface.
The trowel 54 can be displaced along an axis that is approximately perpendicular to the road surface when the trowel is in contact with the road surface. This enables the trowel to accommodate variations in the road height. To this end, the trowel 54 is mounted on three legs 60 that can each be retracted up into the applicator 50. Thus, as the trowel 54 encounters a bump in the road surface, the trowel 54 can rise and fall to pass over the bump.
The trowel 54 can also be pivoted on one or more axes that are approximately parallel to the road surface when the trowel 54 is in contact with the road surface to accommodate variations in the road pitch. To this end, each of the three legs 60 is connected to the trowel 54 by a pivot joint. One of the legs 60a is connected to the trowel 54 at its leading end L, and enables the trowel 54 to pivot on a first axis. The other two legs 60b, 60c are spaced equidistantly from leg 60a, and enable the trowel 54 to pivot on a second axis, which is approximately perpendicular to the first axis.
The road crack repair system 20 further has a surfactant discharge system that includes a surfactant reservoir 62 and spray nozzles 64 that, in use, each spray a surfactant onto the road surface, as indicated by the arrows S, in each of
As noted previously, the control system can be operated from within the cabin 14 of the vehicle 10. This enables monitoring of the position of the applicator 50 and adjustment by direct visual inspection by an operator without the need for remote cameras and video equipment. This is particularly beneficial because an operator can clearly see a crack in the road and guide the applicator 50 accordingly. It will be appreciated that the direct visual inspection can be augmented with a camera and video equipment. This may be of assistance where the operator is within the cabin 14 of the vehicle 10, and use of the applicator 50 immediately in front of the vehicle 10 is sought.
As will be appreciated, relying solely on a camera and video equipment to observe a road crack and to operate the applicator has the disadvantage of narrowing the field of vision. This impairs the operators ability to accurately and rapidly control of the applicator relative to a crack in a road.
The control system is operable to control any of the following activities of the road crack repair system 20:
The system 20 has a pump (not shown) for supplying molten sealant product from the vessel 22 into the conduit 24. The control system is also operable to control operation of the pump. To this end, the control system can adjust the pump flow rate in proportion to the speed of the applicator 50. This ensures that the volume of sealant within the reservoir formed by the trowel 54 on the road surface is maintained at an optimal level.
In addition, the control system is configured such that the operator can have the system 20 automatically commence discharge of sealant from the sealant outlet 52 with initial movement of the trowel 54 on the road surface. As will be appreciated, there is a need to stop sealant discharge from the sealant outlet 52 as the trowel 54 approaches the end of the section of crack to be sealed, and the trowel 54 lifted from the road surface. In use, as the trowel 54 approaches the end of a section of crack, the operator uses the control system to stop discharge of sealant product from the sealant outlet 52. Ideally, the reservoir within the trowel 54 is depleted at the end of the crack.
A valve (not shown) is provided in the conduit 24 immediately upstream of the sealant outlet 52, which enables the conduit 24 to be closed to prevent sealant dripping from the outlet 52.
The control system may also include a joystick (not shown) that is operable by an operator from within the cabin to displace the applicator 50 in transverse and longitudinal directions relative to the vehicle. In certain embodiments, the control system is also operable to automatically rotate the applicator 50 with displacement of the applicator 50 relative to the frame 40 such that the leading end L of the applicator 50 is orientated in the same direction as the displacement of the applicator 50. This ensures that the air jets 58 are directing their respective air streams into the crack.
A single operator can use of the vehicle 10 and system 10 to repair road cracks. In particular, an operator can drive the vehicle 10 and operate the system 20. For safety and accuracy of the repair, this would typically involve stopping the vehicle 10 with the frame 40 over a section of road to be repaired. The crack (or cracks) within that section are then repaired, and the vehicle 10 is then moved on to the next section of road to be repaired. In this way, operation of the vehicle 10 and system 20 are sequential.
In some embodiments, the frame can be configured to be shifted transversely on one or both sides of the vehicle to be partially offset relative to the path of the vehicle.
The support arm 152 includes a guide rod 156 to which bushes 154 are connected and extend outwardly to a housing 160. The housing 160 is rotatably mounted to the bushes, but the bushes 154 and housing 160 comprise a unit that is slidable along the guide rod 156. Movement along the guide rod 156 is controlled by a motor 158 that enables the housing 160 to be raised or lowered relative to the support arm 152 and hence the road.
A top end of the housing 160 is closed and includes an upwardly extending boss 162 to which is connected a swivel leg 164 which, in turn is linked to the sealant conveying hose 124. The swivel leg 164 enables the housing 160 to rotate relative to the sealant conveying hose 124.
A lower end of the housing includes an outwardly extending flange 196 and is closed by cover 170 and includes and downwardly extending neck 172 that defines a shoulder 173.
The neck 172 has a generally cylindrical profile and is closed at its end, but includes an aperture 174 formed in a curved surface of the neck 172.
A tube 176 extends from the boss 162 and terminates at the shoulder 173 such that sealant is supplied from the tube 176 into the neck 172 to flow from the applicator 150 via the aperture 174.
Sealant flow is controlled by adjusting location of the tube 176 within the neck 172. Accordingly, sealant flow is stopped by actuating a motor 180 to lower the tube 176 such that the tube 176 abuts the closed end of the neck 172, thereby closing the aperture 174.
In order to ensure that an appropriate amount of sealant runs into a crack (owing to differences in crack width and depth), sealant exiting aperture 174 falls into a reservoir formed by a trowel 188 in the form of a ring. The trowel 188 is linked by rods 190 to a further ring 192 that extends about the outside of the housing 160. The trowel 188 is biased by a spring 194 into contact with the road by forcing the ring 192 downwardly. Movement of the ring 192 downwardly is limited by the flange 196.
The applicator further includes an air jet for blowing air into a crack to remove loose debris prior to filling the crack with the sealant. The air jet is provided by an air line 182 that extends through an upper end of the housing and terminates at an upper manifold 184. The housing further includes a lower manifold 184 from which extends an air outlet pipe 186. A worker is able to control the direction of an air jet by controlling rotation of the housing 160 relative to the support arm 152 via motor 166 and toothed gears 68, one of which is fixed to an upper portion of the housing 160.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010900219 | Jan 2010 | AU | national |
