Road Coating Device

Abstract

Device for depositing liquid synthetic coatings on road surfaces, which device is fixed to a vehicle via at least one feed pipe connected with at least one mixer and a plurality of containers for the individual components of the synthetic material, means being provided for operating, controlling and metering the synthetic material from the containers, the device comprising a hollow spray arm for discharge of the material, which arm has at least one slit, open at the bottom and of constant width extending transversely to the direction of movement of the vehicle, whose length roughly corresponds to the width of synthetic coating strip required and by means of whose variable spread tranversely to the direction of movement of the vehicle, the coating width is variable; and in that the spray arm is surrounded on all sides by a protective hood which is open at the bottom and whose lower edge maintains a constant space above the road surface.

Description

The invention relates to a device for depositing liquid synthetic coatings on road surfaces, which device is fixed to a vehicle via at least one feed pipe connected with at least one mixer and several if necessary heatable containers for the individual components of the synthetic material, and for which containers are provided means for operating, controlling and metering the synthetic material.

Similar devices for depositing synthetic coatings are already known, in which a plurality of downwardly directed spray nozzles are fixed to a rail. It was discovered, however, that in practice these known devices do not provide a sufficiently even widthwise distribution of the relatively thin synthetic coating layer because differences in the coating thickness appeared as a result of the overlapping of the individual nozzle jets. In addition to these unevenness in the coating thickness other irregularities, caused by winds, were added.

It is therefore the object of the invention to provide a discharge unit for depositing liquid synthetic coatings on road surfaces which, independently of the influence of winds and even during the formation of an optionally variable coating thickness, is in a position to always produce a very thin coating of even and uniform thickness.

According to the invention this object is achieved in that a hollow spray arm is provided for the discharge, which arm has at least one slit open at the bottom and of constant width extending transversely to the direction of movement of the vehicle, and whose length roughly corresponds to the width of the synthetic coating strip and by means of whose variable spread transversely to the direction of movement of the vehicle, the coating width is variable; and in that the spray arm is surrounded on all sides by a protective hood which is open at the bottom and whose lower edge maintains a constant space above the road surface.

It is advantageous if this protective hood is provided with an inspection window in order to observe the synthetic film being discharged from the slit.

In order to allow the wind resistant properties of the protective hood to be fully utilised to its maximum advantage, the gap between its lower edge and the road surface must not be greater than 0.5 to 1 cm. Advantageously the protective hood is therefore provided with its own swivelable runners which constantly run along the road surface and support the weight of the protective hood. The protective hood is thus vertically movable relative the vehicle in a guide whose rigid parts may be arranged on the spraying arm.

It may be of advantage to provide at least the forward edge of the protective hood with a flexible drag skirting, whose free edge rests on the road surface, so that the protective hood directly contacts the road surface at least with its forward edge and does not form a gap.

It is advantageous to be able to vary the width of the coating. For this purpose, in one embodiment of the invention the whole spray arm is arranged in a swivel device by means of which the arm can be moved from its basic posotion perpendicular to the direction of travel, into a position which is oblique to the direction of travel. In another embodiment the slit width corresponding to the width of the coating is varied by means of a slide arranged in the spraying arm.

In order to always ensure an even coating thickness of the sythetic material layer, under all drive conditions and even when varying the effective width of the spray arm - either because of swivel displacement or change in the position of the slide - a control device regulates the quantity of synthetic material being conveyed, both in dependence on the drive speed by means of a measuring wheel travelling along the road surface near the spraying arm, as well as in dependence on the angular position of the spraying arm or the position of the slide.

The invention is now described in more detail by means of an embodiment illustrated by the attached drawing. Shown are:

FIG. 1 the rear half of a vehicle, which carries the device according to the invention and its additional equipment; and

FIG. 2 a cross-section through the device in FIG. 1 according to the invention, in an enlarged scale.

FIG. 1 shows a cut-away section of a side elevation of a vehicle 1 supporting the device according to the invention. A hollow spraying arm 5 is attached to a supporting device 2 which is swivelably and preferably detachably secured to the chassis of this vehicle 1 at a position behind its rear axle 3. As shown by the cross-section in FIG. 2, the whole of the inner space of the spraying arm 5 is divided into two inner chambers by a horizontal separating wall 19, the two chambers being linked by a gap; the lower chamber projecting into a slit 6 of the lower wall of the spraying arm 5. This slit 6 extends transversely to the drive direction of the vehicle 1 and essentially over the whole length of the spraying arm 5 and has a constant width. The length of the slit 6 can be reduced at both sides by slides (31. The slides may be controlled by the control device 20.) The upper inner chamber of the hollow spraying arm 5 represents a pre-distribution chamber 18 into which a pipe 16 is introduced, preferably at two separate points which are described as pipe inlets 17.

In the vehicle 1 are provided heatable storage containers 30 for the individual components of a synthetic mixture 8, composed in one or more mixing containers 15, which mixture is introduced into the pre-distribution chamber 18 from the mixing container 15 by means of a pump and via pipe 16. Any dynamic pressures that may be encountered near the pipe inlets 17 are effectively eliminated within the pre-distribution chamber 18, so that an even pressure distribution exists at the slit 6 and below it a spray film 7 of constant thickness is discharged and deposited on a road surface 4, while the vehicle 1 advances at an essentially constant speed in the direction of the arrow.

According to the invention the spraying arm 5 is surrounded on all sides by a protective hood 10, to shield it from winds, which hood is provided with a window 11 at the back (as seen in the direction of travel) through which may be observed the formation of the spray film 7. It is of course also possible to make the whole protective hood 10 from a transparent material, such as for example acrylic glass. The lower edge of the bottomless protective hood 10 is at an essentially constant distance from the road surface 4 and extends along all sides. This gap between the protective hood 10 and the road surface 4 extending along all sides in the aforementioned embodiment of the invention amounts to 0.5 to 1 cm. In order to maintain this predetermined distance constant, the whole protective hood 10 is mounted on two swivel runners 14, which are fixed to both sides of the protective hood and which run along the road surface 4. To counteract heigh differences relative the vehicle 1, which is subjected to variations in the level, the protective hood 10 is secured to the spraying arm 5 by means of a vertically displacable guide device. This is made up of perpendicularly extending guide bars 12 secured to the inside of the protective hood, which guide bars are introduced through guide sleeves 13 each provided with a longitudinal bore and which sleeves are secured to the spraying arm 5 by means of cross bars. If the vehicle now makes a vertical lifting movement, as the result of unevennesses in the road surface 4, then the guide bars 12 will move inside the guide sleeves 13 and the protective hood 10 can maintain its constant distance relative the road surface 4.

As can best be seen in FIG. 2, the lower forward edge of the protective hood 10 has attached to it a drag skirting 24 which extends over the whole width of the protective hood 10 and its lower edge contacts the road surface 4. Thus the front side of the protective hood 10 rests directly on the road surface 4, so that even small foreign bodies etc. can be pushed away and are prevented from getting underneath the synthetic coating. The drag skirting 24 consists of a suitable flexible material, such as rubber for example.

In order to freely control the width of the coating being continuously deposited on the road surface 4, even while in motion, the whole spraying arm 5, as already mentioned, is provided with a swivel device which is for example arranged on the supporting device 2. By swivelling the spraying arm 5 the effective width of the slit 6 is changed, and thus the spray film being discharged relative the direction of travel. Since the protective hood 10 is fixed to the spraying arm 5, this too follows the swivel movement, whereby the swivel runners 14 can adjust themselves to any desired change of direction. However, when the spray film 7 is discharged diagonally to the direction of travel and when, as a result of the shortened effective coating width the coating thickness has to necessarily increase, it becomes necessary to reduce the material feed sufficiently, in dependence on the swivel lever of the spray arm 5, so that an even coating thickness is always maintained. A control device in the vehicle 1 is therefore coupled with the swivel device of the spraying arm 5 so that the constant coating thickness is maintained.

As already mentioned, the width of the coating layer can be varied by means of slides which are arranged in the spraying arm and which partly close the slit 6. The slide position is varied manually or by remote control. By coupling the slides with the control device it is achieved that the coating thickness is automatically adjusted to the varied slit width.

The control device 20 also has the function of controlling the coating thickness via the feed rate of synthetic material mixture 8 in the hollow chamber of the spraying arm 5 in dependence on the speed of travel of the vehicle 1 in the direction of the arrow. The control member for this regulator circuit of the control device 20 is a finely calibrated speedometer (which is not shown), which is driven by a non-slip measuring wheel 22 running along the road surface 4 and which is connected to the speedometer via a flexible shaft 21. The quantity of synthetic material mixture 8 which is discharged, can be regulated by, for example, varying the feed pump output.

Finally, one form of the embodiment provides for the slit width to be adjustable, preferably between 0 and 2 mm. This width adjustment acts simultaneously over the whole slit, so that the slit limitations extending perpendicular to the direction of travel in the normal position, remain parallel to each other. A slide may also be provided for the width adjustment, and a connection with the control device is possible.

Claims

What is claimed is:

1. Device for depositing liquid synthetic coatings on road surfaces, which device is fixed to a vehicle via at least one feed pipe connected with at least one mixer and a plurality of containers for the individual components of the synthetic material, means being provided for operating, controlling and metering the synthetic material from the containers, the device comprising a hollow spray arm for discharge of the material, which arm has at least one slit, open at the bottom and of constant width extending transversely to the direction of movement of the vehicle, whose length roughly corresponds to the width of the synthetic coating strip required and by means of whose variable spread transversely to the direction of movement of the vehicle, the coating width is variable; and in that the spray arm is surrounded on all sides by a protective hood which is open at the bottom and whose lower edge maintains a constant space above the road surface.

2. Device according to claim 1, in which the protective hood has an inspection window.

3. Device according to claim 1, in which the protective hood is made of acrylic glass.

4. Device according to claim 1 in which the protective hood is arranged for vertical movement in at least one vertically extending guide on the spraying arm and supported by at least two swivel runners which run along the road surface.

5. Device according to claim 1 in which the forward edge of the protective hood has attached to it, extending along its whole width a flexible drag skirting which rests on the road surface.

6. Device according to claim 5, characterised in that the drag skirting is made of rubber.

7. Device according to claim 1, characterised in that the length of the slit in the spraying arm is variable by at least one slide.

8. Device according to claim 7, in which for matching the output with the slit widths each slide is coupled with a control device.

9. Device according to claim 1 in which the relative width in relation to the direction of travel of the spray film being discharged from the slit is adjustable relative the vehicle axle by means of a swivel device for the spraying arm.

10. Device according to claim 9 in which means are provided to control discharge from the slit in relation to the angular position of the spraying arm relative the vehicle axis so that the thickness of the coating deposited on the road surface remains constant.

11. Device according to claim 1 in which the control device for the spraying arm is controlled by a finely calibrated speed sensing device, which is driven by a separate measuring wheel, arranged near the spraying arm, and which will run along the road surface.

12. Device according to claim 1 in which there is inside the hollow spraying arm a predistribution chamber partly separated from the inner chamber adjacent to the slit by means of an essentially horizontal extending separating wall, into which chamber the feed pipe is introduced at at least one point.

13. Device according to claim 1 in which the width of the slit is variable while maintaining the parallel arrangement of the slit limits.

14. Device according to claim 13 in which the slit width is variable between 0 and approximately 2 mm.