EP1556550A1

EP1556550A1 - Asphalt-spreading system

Info

Publication number: EP1556550A1
Application number: EP03807738A
Authority: EP
Inventors: Christian Grindsted Kommune Park & Vej IVERSEN; Poul F. Grindsted Kommune Park & Vej MOLLER
Original assignee: Grindsted Kommune Park & Vej
Current assignee: Grindsted Kommune Park & Vej
Priority date: 2002-10-10
Filing date: 2003-08-14
Publication date: 2005-07-27
Also published as: AU2003250809A1; WO2004033800A1

Abstract

The present invention concerns a spreading system (1), particularly for asphalt, including a vehicle (2) with a dump body (3), preferably in the form of a container (4) with a number of gates (10) at a rear wall of the container (4), and an asphalt-spreading drag (5) that may be connected to a rear end of the vehicle (2), where a driving mechanism (20) powered by the hydraulic system of the vehicle (2) is adapted to be moved between an active position where a driving wheel (15) of the driving mechanism (20) is in a frictional engagement with at least one wheel (7) of the vehicle, and an inactive position where the driving wheel (15) of the driving mechanism (20) is not engaging the wheel (7) of the vehicle, where the driving mechanism (20), besides the driving wheel (15) includes a hydraulic motor (21), a reduction gear (28) and an oil manifold (26) where the hydraulic system of the vehicle (2) is driving connected with the hydraulic motor (21) which via the reduction gear (28) is driving connected with the drive wheel (15).

Description

Asphalt-spreading System

Scope of the Invention

The present invention concerns a spreading system, particularly for asphalt concrete, including a vehicle with a dump body, preferably in the form of a container with a number of gates at a rear wall of the container, and an asphalt-spreading drag that may be connected to a rear end of the vehicle, where a driving mechanism powered by the hydraulic system of the vehicle is adapted to be moved between an active position where a driving wheel of the driving mechanism is in frictional engagement with at least one wheel of the vehicle, and an inactive position where the driving wheel of the driving mechanism is not engaging the wheel of the vehicle.

Background of the invention

By establishing a long and broad road surface, large contractor's machines are used for the work. Typically, here are used self-propelled, large asphalt spreaders where lorries are dumping asphalt into the hopper of the asphalt spreader before spreading on the road surface. Such asphalt spreaders are provided as different types, either as an independent vehicle or a unit pushing a lorry driving in front with the desired speed.

In making small repair work on a road surface, smaller versions of the above mentioned contractor's machines are used for the work. The problem is, however, that the repairs become too expensive, since these smaller contractor's machines are requiring the same personnel as the large machines, and that contractor's machines are expensive to acquire.

By small repair work is meant repair of holes and bumps in a road surface, e.g. wheel tracks, settlings, and potholes produced by wear and climatic influence, being typically small stretches with limited width.

In order to avoid costs of the above mentioned contractor's machines, in many places, instead of asphalt drags coupled to a vehicle, typically a lorry with a dump body, so that the asphalt is loaded from the lorry and over into the asphalt drag. The lorry with the asphalt drag may normally be geared down to about 60 m per hour. In many cases, this spreading speed is still too high, as it is necessary that the spreading speed of the asphalt is adjusted to the working rate of the crew spreading and fin- ishing the asphalt, so that the spread asphalt achieves high quality and fine finish.

Furthermore, due to the high speed of spreading, it will not be possible for the crew to repair areas outside the asphalt drag, implying that several overruns of a road surface for covering all areas needing repair are to be performed.

In order to compensate for the relatively high spreading speed, work gangs with more workers are used. Typically, 5 persons are to be used in order to perform satisfactory repair of a road surface, namely one person driving the vehicle, one person for controlling the asphalt spreading, and three persons for finishing the spread asphalt.

Due to the costs of wages, it is an economic disadvantage when so many persons are involved in the spreading process by small simple repairs of the road surface. For municipalities and counties, this is a limiting factor for how large areas are afforded to repair each year. In the worst cases, this may imply that repairs on bad road stretches are postponed, and the bad road surface may cause accidents.

In order to adjust the spreading speed, experiments have been made with mounting an asphalt drag on a tractor. It appears that there is no great difference in using a tractor or a lorry. Instead, it means another disadvantage since the tractor may drive 30 km/h on public road, whereas a lorry is allowed to drive 70 km/h on public road, according to the Danish Road Traffic Act.

This means that much time is wasted with driving a tractor back and forth to/from the area where the road surface is to be repaired, and that the crew has to stand and wait for unnecessary long time when a new load of asphalt is to be obtained during the spreading as compared with using a lorry. Object of the Invention

It is the purpose of the present invention to provide a spreading system that may be coupled to a vehicle which thereby may be used both for spreading asphalt and for other driving, and that this spreading system has a driving mechanism providing that the speed of the vehicle may be reduced down to 0 m per hour, and that the spreading process may be controlled from one work station, and that the spreading system reduces the need for persons for the spreading process.

This is achieved with a spreading system as specified in the preamble of claim 1 and which is characterised in that the driving mechanism, besides the driving wheel includes an oil motor, a reduction gear and an oil manifold, where the hydraulic system of the vehicle is driving connected with the hydraulic motor which via the reduction gear is driving connected with the drive wheel.

Description of the Invention

In the following is described a spreading system mounted on a vehicle in the shape of a lorry with a dump body. Other kinds of vehicles with dump bodies may be used.

The asphalt drag is connected to a rear end of the vehicle so that when the platform body of the vehicle is tipped, asphalt lying in the body will be tipped directly down into the asphalt drag.

In an embodiment of the invention, the asphalt drag is connected to the rear end of the vehicle with a number of chains providing that the asphalt drag readily may be con- nected/disconnected the rear end of the lorry. Furthermore, the chains are disposed so that the asphalt drag does not tilt when it is dragged after the lorry or lifted up from the ground.

In order to reduce the driving speed of the lorry and thereby the spreading speed of the asphalt, in connection with the lorry there is mounted a driving mechanism coupled to tlie hydraulic system of the lorry and provided with a drive wheel disposed so that it may be moved between an active position, where there is frictional engagement with at least one of the wheels of the lorry, and an inactive position where there is not engagement with the wheel of the lorry.

Thereby is achieved flexibility in using the lorry since by mounting the spreading sys- tern it may not be used for spreading asphalt, implying that there is not to be invested in several types of lorries. Thus it is only necessary to disconnect the drive mechanism so that the drive wheel is in the inactive position in order to use the lorry for common driving with loads in periods in which it is not to be used for spreading asphalt.

In order to achieve the desired effect with reduction of the driving speed, the drive mechanism is made with a drive wheel, an oil motor, a reduction gear and an oil manifold.

The drive wheel in active position is engaging the tyres of the lorry, so that the drive wheel via the reduction gear will transfer the power from the oil motor to the at least one tyre so that the lorry will move back or forward depending on the rotational speed of the drive wheel.

For lorries with more wheel sets, the drive wheel can be placed so that it is in fric- tional engagement with e.g. two tyres. This will typically be the case for lorries with dual rear wheel set.

By using a reduction gear between the oil motor and the drive wheel, it is possible to throttle down the driving speed to 0 m/h.

In a preferred embodiment of the invention, the drive wheel is a Robson wheel having a granulated surface so that the drive wheel is more easily frictionally engaged with the face or the side of the lorry tyre and thereby forces the tyre to rotate. Alternatively, the drive wheel may be designed with projections grasping the surface of the tyres.

By making the drive mechanism as a unit connected with the hydraulic system of the lorry, it is easy to incorporate the drive mechanism in the existing structure of the lorry. For example, the drive mechanism may be placed in connection with the side members of the lorry and between the first wheel set and the rearmost wheel set.

Alternatively, the drive mechanism may be provided in connection with the drive shaft arrangement of the vehicle.

In order to control the spread amount of asphalt from the dump body and down into the asphalt drag, the gates of the container are constituted by side hinged gates that are operated by a number of hydraulic cylinders which are coupled either directly to the hydraulic system of the lorry or to the hydraulic drive mechanism.

The hydraulic control implies that the gates may be opened and put in different positions so that the width of the opening at rear of the lorry container has a desired width enabling discharge of an amount of asphalt down into the asphalt drag corresponding to the spreading speed.

Furthermore, the side-hinged gates, which may be opened to the rear, will have a funnel function for asphalt lying in the container, so that the asphalt will be led down into the desired area of the asphalt drag. It may be an advantage if the repair area has a narrower width than the asphalt drag.

The control of the asphalt drag is furthermore hydraulically comiected to the drive mechanism via a distributor providing for excess oil from the drive mechamsm to be conducted to the asphalt drag and may be used for e.g. lifting and lowering the asphalt drag, whereby the layer thickness of the spread asphalt may be adjusted.

By using the drive mechanism on the vehicle, the spreading speed can be reduced, and subsequently it will be possible to reduce the number of persons that are to be used for finishing the spread asphalt. Thus there will only be need for one person to control the spreading of the asphalt, one person for driving the lorry and one person for finishing the spread asphalt. In order that one person can control the entire spreading process, the spreading system further includes a control panel with a number of control valves and switches that are disposed on the asphalt drag and/or the rear end of the lorry, and are adapted for controlling the hydraulic cylinders of the container gates, the drive mechanism and the asphalt drag.

As control valves and switches are placed on the asphalt drag and/or in vicinity of the rear of the vehicle, it is possible that the entire spreading process, regarding spreading speed, discharge of asphalt from container to asphalt drag and the asphalt drag itself may be controlled by one person having a work position close to the rear end of the lorry.

In an embodiment of the invention, these control valves and switches ma be remotely controlled so that one person possibly may go around with a portable console and con- trol the spreading process therefrom. However, this requires that in connection with asphalt drag and vehicle, a receiver is to be provided.

In a second embodiment of the invention, it may be possible to construct the control panel so that it furthermore may control the front wheel set of the lorry, implying that it is not necessary to have a person sitting in the lorry. This possibility is, however, only present when/if this spreading system is allowed by the work environment authorities that are to judge whether it is safe to remote control a lorry from an external position. Acceptance of the spreading system will imply that only two persons are required for the spreading process.

There are the following advantages of using a spreading system according to the present invention:

- The driving mechanism of the spreading system is cheap to acquire and easy to fit while at the same time the drive mechanism may readily be mounted in most standard vehicles.

- The required number of persons is reduces as there is only need for a maximum of three persons to perform the spreading process and finishing treatment as compared with today, where a minimum of five persons are used.

- The quality and finish of the road surface is improved as the spreading speed is adjusted so that time is provided for finishing the spread asphalt.

- Making lesser repair works in the entire width of the road surface may be per- formed in the same workflow.

The asphalt drag is adapted to be connected to and disconnected from the rear end of the lorry, which means that it is not necessary to invest in self-propelled asphalt spreaders.

Short Description of Drawings

The invention is explained in more detail in the following with reference to drawings where:

Fig. 1 shows a side view of a lorry with asphalt drag according to the invention, Fig. 2 shows the rear end of a lorry with an asphalt drag according to the invention, and

Fig. 3 shows a schematic setup of the drive mechanism.

Detailed Description of the Invention

Fig. 1 shows a spreading system 1 including a common lorry 2 with a set of front wheels 8 and a set of dual rear wheels 7.

The lorry 2 has a dump body 3 in the form of a covered container 4 with side hinged gates (not shown) disposed at the rear end of the container 4.

In connection with the rear end of lorry 2 is coupled an asphalt drag 5 which in the shown embodiment is coupled to the lorry 2 with chains 6 and disposed so that asphalt from the container 4 will be loaded directly into asphalt drag 5 when the container 3 is tilted, and the side hinged gates (not shown) are opened.

The asphalt drag 5 is provided with height adjustable runners 9 providing the possibility of adjusting the thickness of the spread asphalt. The asphalt drag 5 is furthermore provided with a control panel 11 with a number of control valves 12, and the rear end of the lorry 2 is equipped with a control panel 13 with a number of control switches 14.

As these control panels 11, 13 are disposed in immediate vicinity of each other, it will be possible for one person to control the entire spreading process and the movement of the lorry 2 from a work station near the rear end of the lorry. 2.

When the asphalt drag 5 is lifted up from the ground, it is possible e.g. to transport it to the area where the road surface is to be repaired.

The drive wheel 15 (Robson wheel) is here shown in inactive position, where it is not engaging the dual rear wheel set 7. In an active position, the drive wheel 15 will be in frictional engagement with the surface of the tyres in the dual rear wheel set 7.

Counter-clockwise rotation of the drive wheel 15 will imply that both wheels in the dual rear wheel set 7 are forced to clockwise rotation.

Fig. 2 shows the rear end of lorry 2 on which the asphalt drag 5 is coupled to the chains 6 in elevated position.

The side hinged gates 10 of the container 4 are controlled by hydraulic cylinders 16 providing the possibility of opening the rear end of the container 4 to a pre-determined width, whereby the discharged amount of asphalt may be determined.

Furthermore, the side hinged gates 10 will act as guide plates so that asphalt in the container 4 will be conducted down into the desired area of the asphalt drag 5.

Fig. 3 shows a schematic diagram of the drive mechanism 20 that include an oil pump 21 connected to the hydraulic system 22 of the lorry.

Oil pump 21 is a double pump (preferably 2 x 56 1) so that hydraulic oil is conducted to both drive mechanism 20 and dump body 3, and to the cylinders 16 of the gates 10. From oil pump 21, hydraulic oil is conducted through a three-way valve 24 and onward to a pressure relief valve 25, and then to an oil manifold 26 providing that hydraulic oil is distributed to the orbit motor 27 and the asphalt drag 5.

Via reduction gear 28, the orbit motor 27 drives the drive wheel 15 having frictional contact with the wheels in the dual rear wheel set 7.

The return oil from the asphalt drag 5 and the orbit motor 27 is returned to an oil cooler 29 and a tank 30, after which it is pumped out again to the drive mechanism 20 or dump body 3 via the oil pump 21.

Claims

1. Spreading system (1), particularly for asphalt, including a vehicle (2) with a dump body (3), preferably in the form of a container (4) with a number of gates (10) at a rear wall of the container (4), and an asphalt-spreading drag (5) that may be connected to a rear end of the vehicle (2), where a driving mechanism (20) powered by the hydraulic system of the vehicle (2) is adapted to be moved between an active position where a driving wheel (15) of the driving mechanism (20) is in frictional engagement with at least one wheel (7) of the vehicle, and an inactive position where the driving wheel (15) of the driving mechanism (20) is not engaging the wheel (7) of the vehicle, characterised in that the driving mechanism (20), besides the driving wheel (15) includes a oil motor (21), a reduction gear (28) and an oil manifold (26), where the hydraulic system of the vehicle (2) is driving connected with the hydraulic motor (21) which via the reduction gear (28) is driving connected with the drive wheel (15).

2. Spreading system (1) according to claim 1, characterised in that the gates (10) of the container (4) are constituted by side-hinged gates (10) that are operated by a number of hydraulic cylinders (16).

3. Spreading system according to claim 1, characterised in that it further includes a control panel (11, 13) with a number of control valves (12) and switches (14) that are provided on the asphalt drag (5) and/or the rear end of the vehicle (2) and adapted for controlling the hydraulic cylinders (16) of the container gates (10), the drive mechanism (20) and the asphalt drag (5).