WO2005068724A1

WO2005068724A1 - A method and device for spreading bulk goods, preferably asphalt, to produce roadways and the like

Info

Publication number: WO2005068724A1
Application number: PCT/SE2004/001845
Authority: WO
Inventors: Conny Andersson
Original assignee: Carlsson, Allan
Priority date: 2004-01-14
Filing date: 2004-12-13
Publication date: 2005-07-28
Also published as: SE0400059L; SE526407C2; SE0400059D0; DE112004002583T5

Abstract

The present invention relates to a method in connection with the spreading of bulk goods, preferably asphalt, to produce roadways and the like, whereby the bulk goods is homogenised in a systemator that is moveable in the spreading direction and from which the bulk goods is fed out from a lower part, which lower part is a rear part of the systemator as seen in the direction of travel. The method is characterised in that the bulk goods, after exit from the systemator, is fed out angled to the direction of travel, during simultaneous compression in one or more tube(s) (3, 4) having a longitudinal opening facing the roadway. The invention also relates to a device for practising the method.

Description

A METHOD AND DEVICE FOR SPREADING BULK GOODS, PREFERABLY ASPHALT, TO PRODUCE ROADWAYS AND THE LIKE

TECHNICAL FIELD The present invention relates to a method in connection with the spreading of bulk goods, preferably asphalt, to produce roadways and the like, whereby the bulk goods is fed from a container to a spreading device. The invention also relates to a spreading device for the practising of the method of spreading.

PRIOR ART

The spreading of bulk goods, preferably asphalt, is a technique that has been well known for many decades. According to this technique, a slow moving vehicle spreads the bulk goods that after the spreading is compressed, usually by pressing the goods onto the bed by aid of a heavy roll. The bulk goods consisting of suitably sized chippings of stone, suitably larger than 4 mm, and a binder in the form of a bitumen mixture, are stored at high temperature in the vehicle, it being striven after that the goods should not cool until it has been compressed onto the roadway. In addition to the chippings of stone, intended to give a high stability and wear resistance and that exist in an amount of 75 % of the surfacing goods, it consists of fine materials, fillers and binders that is called mastic. The mastic, that can be considered as a liquid at the time of spreading, is intended to fill the air space formed in the oriented skeleton structure that consists of the chippings of stone. It is of major importance that the goods is as homogenous as possible at the time of spreading, and therefore dedicated homogenisation devices have been arranged in order for the goods not to separate into different components. Such a device, called a systemator, is described in the international patent publication WO 97/00124. This systemator gives a nearly perfect homogenisation of the surfacing goods.

Known and modern spreading machines feed the surfacing goods from the systemator by aid of one or more screws of specialised design, to the actual spreading step where the goods is led out to the side by aid of two screws, and uniformly falls to the bed, where after it is compressed by aid of a subsequent device.

THE TECHNICAL PROBLEM It is important that the chippings of stone in the surfacing are oriented stone to stone, and that they form a skeleton. This means that an excessive amount of air pockets must not exist in the final surfacing. By the known method of spreading loose bulk goods, an undesired separation takes place after the systemator, why one strives to impose an acceptable structure on the separated goods by trying to lock the components of the goods by a forced outer force, instead of taking advantage of the natural behaviour of unstructured non-uniform material to find its own place and thus to form a more homogeneous composition in the final surfacing, at the same time as the compacting requirement is dinώ ished.

THE SOLUTION

By the present invention, the above problem in connection with known technique has been solved and a method has been achieved for spreading bulk goods, preferably asphalt, to produce roadways and the like, which method is characterised in that the bulk goods in the spreading device is fed out lateral to the direction of travel, but the feeding-out device might very well be angled like a road planer, during simultaneous compactmg in one or more spreading/feeding-out tubes having at least one longitudinal opening that is at least partly turned backwards. Preferably, said opening is an integrated opening that is partly turned down facing the roadway and partly turned backwards.

According to the invention, it is suitable that the compaction is achieved by compacting screws, that can be replaced by e.g. pistons, eccentric presses or the like, pressing the bulk goods into the feeding-out tube(s).

For the practising of the invention, it is important that the compaction, i.e. the coefficient of fullness of the bulk goods in said feeding-out tube, is ensured by a feeding-in of bulk goods into the feeding-out tubes that is synchronised with the spreading from the feeding-out tube(s), and preferably also that the feeding-in of bulk goods into the feeding-out tubes by the compacting screws is synchronised with the feeding-out of bulk goods from said container.

According to a preferred embodiment of the invention, the opening of the feeding-out tube or tubes facing the roadway can be controlled by aid of a vertically adjustable support behind the feeding-out tube or tubes.

The invention also relates to a device for practising the method according to the above, which device comprises one or more feeding-out tubes arranged laterally to the direction of travel and having at least one longitudinal opening in each such tube, which opening is at least partly turned backwards, and means for feeding in the bulk goods, preferably the asphalt, into the feeding-out tube or tubes as well as compacting it in the same. Said means may comprise a compacting screw assigned to the respective feeding- out tube, which compacting screw is arranged to press in the bulk goods into the tube. Furthermore, the size of said at least one longitudinal opening is vertically adjustable to control the thickness of the string of bulk goods that is laid out by the respective feeding-out tube.

The size of the portion of said opening that is turned backwards is according to the chosen embodiment adjusted by a vertically adjustable support that is constituted by the front part of a screed, hydraulic cylinders preferably being arranged to raise and lower the screed plate or plates. Preferably, the screed plate(s) is/are arranged such that its/their height adjustment can be varied along the length of the screed plate(s), in order to achieve a desired slope or a varying thickness of the string of bulk goods that is laid out.

According to the invention, it is furthermore beneficial that the feeding-out tube or tubes is/are telescopic and that it is/they are longitudinally displaceable by aid of hydraulic cylinders. It is also a distinctive feature of the invention that the feeding-out screw or screws has/have a laterally displaceable dolly at the outer end of the tube or tubes, which displaceable dolly can be constituted by the outer end of an outer telescope section.

The device according to the invention is preferably part of an integrated equipment that also comprises said container. Transporting means are arranged for conveying the bulk goods from the container to said compacting devices, i.e. said compacting screws according to the preferred embodiment, and means for synchronising the feeding of bulk goods from the container to the compacting screw/screws or the like, and from the compacting screw/screws or the like and into the feeding-out tube/tubes, with the feeding-out of bulk goods from the feeding-out tube/tubes.

Finally and according to the invention, the feeding-out tubes should be articulated about a fixed point at the centre of the spreading device.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, the invention will be described in greater detail with reference to the attached drawings in which: Fig. 1 in a side view and partly in cross-section, shows a complete spreading device comprising the present invention, during spreading of bulk goods onto a roadway, Fig. 2 shows the spreading device as seen from above and partly in cross-section, as well as a section of a bulk goods container and feeding screws from the container to the spreading device, Fig. 3 partly in cross-section, shows the invention as seen from behind in the direction of travel of the spreading machine, and Fig. 4 shows the object of the invention as seen from the side and in a larger scale.

DETAILED DESCRIPTION

Fig. 1 shows a nearly complete spreading device for concrete and gravel products, preferably asphalt, comprising a bulk goods conveyor 1 of known type, a so called systemator 2 such as an asphalt container with a homogenisation device of the type mentioned above, which systemator receives bulk goods from the bulk goods conveyor 1, and transports it out to the actual spreading device 22 behind the systemator. The bulk goods conveyor and the systemator are provided with wheels (caterpillars are also conceivable), and are intended in connection with the spreading slowly to be pulled to the left in Figs. 1 and 2. As is seen in Figs. 2 and 3, the systemator 2 comprises two specialised parallel screws 20, 21 for feeding of the bulk goods.

Figs. 2 and 3 show the systemator 2 and the spreading device 22 according to the invention, as seen from above and from behind, respectively. The spreading device comprises a left lateral feeding-out tube 3, and a right lateral feeding-out tube 4. The left tube 3 extends from an inner end wall 25, somewhat to the right of the vertical symmetry plane 23 of the device, and out to the left to an outer end wall 26. Correspondingly, the right tube 4 extends from an inner end wall 27, somewhat to the left of the symmetry plane 23, and out to an outer end wall 28. Inlet openings 29 and 30 for bulk goods are positioned in the inner end walls 25 and 27, respectively. To the right of the inlet opening 29 a short feed tube 31 for the left tube 3 is connected to the inlet opening 29, and to the left of the inlet opening 30 a feed tube 32 for the right tube 4 is connected to the inlet opening 30.

Feed tube 31 contains a compacting screw 5, and feed tube 32 contains a compacting screw 6, arranged to be revolved by hydraulic motors 12 and 13, respectively. The rear end walls of feed tubes 31 and 32 have been denoted 33 and 34, respectively. Feed tubes 31 and 32 are open in the upwards direction, such that the systemator 2 and its two screws 20 and 21 can deliver the backwards fed bulk goods to the lateral screws 5 and 6 in tubes 31 and 32, respectively. For the delivery of the bulk goods to the respective screw 5 and 6, the upwardly open feed tube 31 is covered by a hood 35, Fig. 4, that is tightly attached to a first rear opening of the systemator 2. Similarly, a tube 36 leads from a second rear opening in the systemator 2, to the compacting screw 6 for the right tube 4 that is arranged further back in the feeding-out device 22.

A left screed 7 is arranged behind the left feeding-out tube 3, which screed consists of a screed plate 7a and a front, vertical wall 16. Similarly, a right screed 8 having a screed plate 8a and a front vertical wall 17 is arranged behind the right feeding-out tube 4.

Screeds 7 and 8 are vertically adjustable in relation to tubes 3 and 4, by aid of hydraulic cylinders 11a and 1 lb, respectively. The hydraulic cylinders 11a and 1 lb are mounted on a not shown stand that is fixedly united with the supporting structures of the systemator 2. Moreover, the hydraulic cylinders 11a and 1 lb are individually manoeuvrable, and screeds 7 and 8 are articulately connected with said stand in the area of the centre of the feeding-out device 22, in order to achieve a desired lateral slope of the surfacing and/or to achieve a desired camber and/or a varying thickness of the string of bulk goods that is laid out.

The left feeding-out tube 3 has a lower opening 14 that faces the roadway 49. As seen in cross-section, tube 3 extends from screed plate 16 in a circular arc of 225° upwards forwards downwards, where after the tube ends with a front deflector 41 facing obliquely downwards backwards. The right tube 4 that is arranged further back in the feeding-out device 22, is arranged correspondingly. Its deflector that faces downwards backwards, is denoted 42. The downwards facing opening 14 of tube 3 is accordingly forwardly defined by the deflector 41, and backwardly by the front end wall 16 of screed 7. In the same way, the downwards facing opening 15 of tube 4 is defined by the front deflector 42 and the end wall 17 of screed 8.

By raising screeds 7 and 8, from the screed plates 7a, 8a being in contact with the unpaved roadway 49, openings 50 and 51 are created in a direction backwards in relation to the feeding-out tubes 3 and 4. The vertical size of these openings 50 and 51 determines the thickness of the strings of bulk goods 52 and 53 that are laid out by the feeding-out tubes 3 and 4, respectively. By raising or lowering screeds 7 and 8, from the base line that corresponds to the surface of the existing roadway 49, the thickness of the surfacing can be controlled. The feeding-out tubes 3 and 4 are telescopic, and can be extended and contracted by aid of hydraulic cylinders 9 and 10. Also, screeds 7 and 8 are extendable and follow tubes 3 and 4 in their extension and contraction, respectively. In addition, the screeds are longer than the tubes 3 and 4, such that the left screed 7 extends to the right, well past the feed screw 5 of tube 3. Similarly, the right screed 8 extends to the left, well past the feed screw 6 of the right tube 4.

The feeding-out device 22 operates according to the following. The concrete and gravel product, preferably asphalt, is homogenised in the systemator 2, from which the bulk goods is pressed backwards through hoods/tubes 35, 36 and into the two short feed tubes 31 and 32 of the feeding-out device. By aid of the compacting screws 5 and 6, the bulk goods is pressed into the left feeding-out tube 3, and into the right feeding-out tube 4, respectively, in which tubes the bulk goods is compacted, such that the tubes are filled with homogenised and compacted asphalt material all the time. This is pressed laterally towards the end walls 26 and 28 of the feeding-out tubes, backwards towards the vertical walls 16 and 17 of screeds 7 and 8, respectively, and forwards towards deflectors 41 and 42 that in turn are pressed to the roadway by the pressure from the spreading device 22 and the bulk goods present therein, whereby bulk goods is largely prevented from rushing forth from the feeding-out tubes 3 and 4. Instead, the bulk goods is pressed out backwards through feeding-out openings 50 and 51, Fig. 1, below screeds 7 and 8, whereby the thickness of the laid out strings 52 and 53 of bulk goods is determined by adjustment of the height of screed plates 7a and 8a above the unpaved roadway 49.

Without restricting the invention to a particular theory, it is the belief of the applicant that the following conditions occur in connection with the compacting of the bulk goods and the spreading of the same onto the roadway, to a desired thickness. At the spreading, a movement takes place in the material. This allows the stone particles in the bulk goods to orient such that they get in contact with each other, and this tendency occurs in the tubes in which the bulk goods is compacted, as well as when the bulk goods leaves the tubes in order to be pressed in under the screeds. This orienting of the stones in the bulk goods is believed to increase the stability of the surfacing. In order for this effect to be achieved, it is also essential that the bulk goods is fed into the feeding- out tubes 3 and 4, by aid of the compacting screws 5 and 6, at the same rate as the bulk goods leaves the feeding-out tubes 3 and 4 to be pressed in under screed plates 7a and 8a, i.e. that feeding-in and feeding-out are synchronised. In order for this to be accomplished, pressure sensors can be arranged, e.g. by sensing the force on the outer end walls 26 and 28 of tubes 3 and 4. This can take place by recording the hydraulic pressure in the devices 9 and 10 provided for the telescopic adjustment of the length of feeding-out tubes 3 and 4. It is also essential that the bulk goods is fed to the compacting screws 5, 6 at such rate that the compacting screws all the time have a sufficient amount of bulk goods to feed into the feeding-out tubes 3 and 4, at the rate that the bulk goods is spread onto the roadway.

The invention is not limited to the shown embodiment, but can be varied in many ways within the scope of the claims, the person skilled in the art realising that many different types of bulk goods can be used, even if it primarily is for the application within the field of gravel and concrete, preferably asphalt, that an improved solution is striven after.

Furthermore, it is realised that shapes can be used for the feeding-out tubes other than strictly cylindrical, such as conical feeding-out tubes, whereby the end walls 26, 28 may be eliminated since in the case of a conical tube, the counter pressure required to press out the bulk goods is created by the successively reduced diameter. Moreover, it is realised that instead of telescopically displaceable parts included in the feeding-out tubes, the width of the total string laid out can be increased by using more than two (e.g. four) feeding-out tubes that preferably are arranged such that they can be moved (in their entirety) so that the width of the total surfacing string can be adjusted as needed.

Claims

1. A method in connection with the spreading of bulk goods, preferably asphalt, to produce roadways and the like, in which the bulk goods is fed from a container to a spreading device (22), characterised in that the bulk goods in the spreading device (22) is fed into one or more feeding-out tube(s) (3, 4) in a direction that is lateral/angled to the direction of travel, during simultaneous compaction in said one or more feeding-out tube(s) (3, 4), and is fed out from said feeding-out tube(s) via at least one longitudinal opening in said tube(s), which opening is at least partly turned backwards.

2. A method according to claim 1, characteri se d in that the compaction is achieved by compacting screws (5, 6), or a similar device, that presses the bulk goods in the longitudinal direction of the tubes, which longitudinal direction is lateral/angled to the direction of travel.

3. A method according to any one of claims 1 or 2, characterised in thatthe coefficient of fullness of the bulk goods in the compacting screw(s) in the feeding-out tubes is kept essentially invariable.

4. A method according to any one of claims 1-3, characteris e d in that the thickness of the laid out surfacing is controlled by aid of a vertically adjustable wall (16, 17) behind the respective feeding-out tube.

5. A device for practising the method according to any one of claims 1-4, characteris ed in that one or more feeding-out tube(s) (3 , 4) is/are arranged lateral/angled to the direction of travel of the feeding-out device, and having at least one longitudinal opening (50, 51, 14, 15) that is at least partly turned backwards, and in that means (5, 6) are arranged to feed bulk goods into and compacting the bulk goods in the feeding-out tube and/or tubes.

6. A device according to claim 5, characteri sed in that said means (5, 6) comprise a compacting screw assigned to the respective feeding-out tube, which compacting screw is arranged to press the bulk goods into the tube.

7. A device according to claim 5 or 6, characteri s e d in that the size of said at least one longitudinal opening is vertically adjustable to control the thickness of the string of bulk goods that is laid out by the respective feeding-out tube.

8. A device according to any one of claims 5-7, characteri s e d in that said feeding- out tube has a laterally displaceable dolly at the outer end thereof, which dolly is constituted by the outer closed gable-end of the feeding-out tube (3, 4).

9. A device according to any one of claims 5-8, characteri s ed in that the size of the longitudinal feeding-out opening is defined by a vertically adjustable wall at the rear part of the feeding-out tube, as seen in the direction of travel.

10. A device according to claim 9, characteri s ed in that said wall is constituted by the front part of a screed (7, 8).

11. A device according to any one of claims 8-10, characteri s ed in that hydraulic cylinders (1 la, 1 lb) are arranged to raise and lower the screeds (7, 8).

12. A device according to any one of claims 1-11, characteri s ed in that the feeding-out tube(s) is/are telescopic and can be altered in length, or can be displaced in its/their entirety by aid of hydraulic cylinders (9, 10).

13. A device according to any one of claims 1-12, characteri s e d in that the feeding-out tubes (3, 4) and the screeds (7, 8) are arranged such that the longitudinal and lateral profiles of the surfacing are variable.