In regard of roads having gravel surfacing, it is usual to trim the roadway by scraping it at regular intervals by means of a motor grader or the like. This also frequently entails gravel material to end up by the side of the roadway in a not desired manner and thus, at regular intervals, it is necessary to replenish the top- covering material, which is expensive.

When clearing roads of snow, a swift removal of snow and ice from the road surface after the downfall is favourable. This is valid in general for all types of roads. Usually, paved roads are then salted or sanded in order to get protection against skidding.

However, as for gravel roads, it is considerably more difficult both to clear them of snow and carry out anti-skid treatment. As regards the snow clearance, it is difficult to remove as much snow as possible without clearing away too much of the top covering, in the form of gravel, at the same time as the snow. After a winter season with a number of passages by a snow plough, it is, therefore, inevitable that a fairly large quantity of gravel is ploughed into the ditch or beside the road. In addition to the snow ploughing, this is also due to a common method in which the idea is to"scratch"or"scarify"the top layer of the gravel road with a variety of different types of so-called scarifiers, in order to achieve anti-skid treatment. The ice is then removed by the scarifier and the gravel is exposed, or the ice surface is scratched in order to make it rougher, which enables sand from possible sanding to remain longer on the road. However, to sand a gravel road often involves drawbacks, amongst other things the traffic soon will make the sand"blow"away and skidding recurs. Furthermore, sanding implies that the sand still remaining on the road at the next snowfall will become either compacted by traffic or cleared away. Of course the same goes for the gravel torn up by scarifying.

Even when the roadway is not covered with snow, but merely ice, the same type of equipment as mentioned above for clearing of snow is utilised, with the same disadvantages and problems as a result.

This all imposes substantial costs to the community, since gravel roads constantly need to be supplied with new material, in particular after the winter, in order to maintain acceptable quality standards of the road. In view of the environ- mental perspective, it is, furthermore, deemed advisable to reduce the number of passages employed in various tasks.

By SE-B-458532, a scarifier tool is previously known which is directly mounted to a road-grader blade. When the grader is utilised for clearing of snow, simultaneously this tool tears up the surface of the road. The object is, as dis- cussed above, to tear up possible ice and expose some gravel at the surface, in order to gravel the ice. However, a major disadvantage of this recognised con- struction is that a substantial quantity of the gravel torn up will not stay at the road surface, but will instead be cleared away by the motor grader along with the snow, since the scarifier tool, as mentioned above, is attached directly to the grader blade. Hereby, the purpose of the scarifying fails, by the fact that the gravel torn up does not remain at the road surface, and furthermore valuable road material in the form of gravel is lost by the snow clearance, which has to be replaced later on.

According to US-A-5140763, a scarifying device is also known, which is attached at the rear of a grader blade. The scarifying device comprises fingers that tear up the surface of the road. Said fingers are tightly arranged with the purpose of moving the extricated material sideways, in the same manner as the grader blade. Therefore, this device causes the same problems as described above.

The object of the present invention is to solve the above-mentioned prob- lems. This object is attained by the device for scarifying as defined in the charac- terising clause of claim 1, the device for treatment of a roadway as defined in the characterising clause of claim 10, and a method as defined in the characterising clause of claim 13.

Thus, according to the present invention, a device for scarifying a roadway is characterised in that it has a plurality of scarifier members including scarifier points and individual holding devices for the scarifier points, which scarifier mem- bers are positioned at a distance from each other, spacings being formed between the respective scarifier members, allowing said sand, gravel and/or ice as well as said material situated on the roadway to pass between the scarifier members.

Hereby the benefit of enabling scarifying without removal of existing material on the road surface, in the form of, for instance, gravel top-covering or sand, is

obtained. In the case of scarifying an icy roadway, or a roadway already cleared, both ice and gravel or sand are torn up, if sanding has been carried out, resulting in a graveled or sanded roadway.

In this manner the existing road material, the gravel, is made better use of since it does not disappear out in the ditch at grading or snow clearing, but remains on the roadway. This constitutes a substantial cost saving, both in regards of gravel material not needed to be replenished, and other resources otherwise required for supplying the road surface with new material.

By way of the ice, on an icy roadway, in this manner being mixed with gravel, the need of sanding the road is avoided, which constitutes an additional cost saving.

Advantageously, the scarifying device may comprise guidance members for guiding the torn-up material in a direction inwards to the roadway. Said guid- ance members are advantageously formed as plates arranged behind the scarifier points as viewed in the direction of travel of the vehicle and the device. They are advantageously arranged so that they form an angle of 30°-70° in relation to the direction of travel of the vehicle. This implies the advantage that, when scarifying one side of the road, the gravel that is torn up is relocated inwards to the centre of the road, which in addition contributes to the saving of gravel.

The scarifier points are preferably arranged in a resilient way, in order to obtain a shock-absorption, which improves the structural strength and the service life of the device. Hereby, the additional advantage of the entire device becoming much more pliable and following possible irregularities in the roadway is achieved, whereby the scarifying becomes more efficient and a more completed result is attained.

At tests, it has been established that the device according to the invention has about a threefold capacity at scarifying off ice compared to recognised devices.

Preferably, the scarifier points are rotatable around the longitudinal axis thereof. Preferably, the scarifier points have a sintered carbide metal tip. In order to achieve efficient scarifying, the scarifier points are preferably arranged so that the longitudinal axis thereof forms an angle to the road surface within the interval 20° to 90°. The scarifier points consist preferably of"studs"having sintered carbide

metal tips, which preferably are replaceable. These may for instance consist of the type of"studs"which form a part in the so-called System 2000, which is commer- cially available.

Foremost, the scarifying device as described above is intended to be mounted as an autonomous unit at a vehicle of a suitable type. In an alternative application of the general idea of the invention the scarifying device may be com- bined with a device for clearing snow having a blade, for instance a grader blade, which removes snow. In this case, the scarifying device is arranged behind the blade and at a distance from the blade, as viewed in the direction of travel of the device. By arranging scarifier members in the form of scarifier points at a distance from the blade and behind the blade, the benefit is obtained that the blade initially disposes of the snow and not until then the scarifying devices with the scarifier points thereof will scratch the road surface behind the blade so that the ice is torn up and also so that the gravel of the road surface is exposed, which results in an improved gripping power of the vehicles travelling on the road. Thus, by way of the proposed device it is possible both to clear away snow and scarify a gravel road simultaneously in an effective manner.

An additional advantage is that the scarifier members with the scarifier points thereof, which thus are abutting against the road surface at a distance behind the blade, simultaneously constitute a support foot preventing the blade from cutting to deep into the road.

Additional advantages and features will be seen in the remaining depend- ent claims.

The invention will now be described with reference to two examples of embodiment, as illustrated in the enclosed drawing figures, in which: Figure 1 schematically depicts a device for scarifying according to the present invention, as viewed laterally, Figure 2 schematically depicts a view of the device of figure 1, taken along the line A-A, and also a roadway area where the device travels in the direction B, Figure 3 schematically depicts a motor grader as viewed from above, equipped with a device for treatment of a road in accordance with the present invention,

Figure 4 depicts an enlarged schematic view of the framed area of figure 3, illustrating a device in accordance with the present invention, as viewed from above, and Figure 5 schematically depicts a scarifying device in accordance with the pre- sent invention, mounted to the blade of, for example, the motor grader depicted in figure 3.

The scarifying device 1 illustrated in figure 1 comprises a number of scari- fier members 6 including scarifier points 10 arranged in order to, during scarifying, abut against a road surface and to some extent penetrate the surface in order to achieve the intended effect. Commonly, the intended effect is to tear up the ice found at the road surface and advantageously also gravel from the road surface so as to mix this by means of the scarifying treatment, or, should the occasion arise, only to tear up gravel or sand having become packed too hard by driving. Prefe- rably, the scarifier points 10 are rotatable around the longitudinal axis thereof in order to achieve an effective scarifying effect upon the road surface. Advanta- geously, the same are also arranged at an angle to the road surface so that the longitudinal axis thereof forms an angle within the interval 20°-90°. Preferably, they are arranged with an angle of 45-60° to the road surface.

The scarifier members 6 also comprise individual holding devices 4 for the scarifier points. As in particular can be seen in figure 2, the scarifier members are positioned at a distance from each other, so that spacings are being formed bet- ween the respective scarifier members, allowing sand, gravel and/or ice 7 at the road surface to be scratched, or other material situated on the roadway, to pass between the scarifier members, simultaneously as the scarifier members scarify the road surface. The distance between the scarifier members is preferably of the magnitude of 50-150 mm, and advantageously of 60-80 mm.

Advantageously, the holding device 4 of each scarifier point comprises a spring 11. As indicated in figure 1, preferably the spring 11 is a short coil spring, comprising only one or a few turns, and one free end of which constitutes a point of attachment for a scarifier point 10. The spring could, for instance, be made out of round bar iron. The function of the spring is to damp the propagation of the shocks to which the scarifier point is exerted, so that an improved structural

strength is attained. However, also other embodiments of the holding device are feasible, with or without spring action.

The holding devices 4 are attached at a common longitudinal carrier device 8. In the example illustrated, the respective spring 11 is mounted to the car- rier device by the other free end thereof. The carrier device may, for example, con- sist of some type of square-iron or the like.

According to a preferred embodiment, the scarifying device also comprises guidance members 12 for guiding the torn-up material at an angle to the direction of travel B of the propelling vehicle, so that it is brought inwards to the centre of the roadway. As is illustrated in figure 1 and figure 2, said guidance member may be of the design of a vertical plate 12, extending downwards to the proximity of the road surface and having a lower edge which extends parallel to the road surface. The plate preferably forms an angle of approximately 30°-70° to the direction of travel, advantageously approx. 45°. The guidance member could as well serve as a holder for the scarifier point 10, which then is arranged at the lower end of the guidance member and at the front tip thereof. However, in the example illustrated, both the guidance member and the scarifier point are attached at the lower free end of the spring 11. The number of guidance members thus equals the number of scarifier points and also the number of springs, in the example illustrated. The guidance members guides the torn-up material in a direction as is illustrated by the arrows A in figure 2, and which results in the torn-up material being guided inwards to the centre of the roadway when the device is utilised and is mounted to a suit- able vehicle which travels along one side of the roadway.

Advantageously, the scarifying device is also provided with some type of actuator 15, illustrated with a piston in figure 1, by means of which the scarifying device may be elevated and lowered in relation to the roadway.

The scarifying device according to the present invention is intended to be mounted on a vehicle, e. g. at the front or the rear of a tractor, a semi truck or some type of road maintenance machinery. It may also be feasible to mount the device under the vehicle. If the vehicle already is fitted with some type of actuator fit for use, it could be adequate to attach the scarifying device thereto. For instance, tractors are commonly equipped with a so-called three-point connector to suspend a variety of implements, and by means of which the implement tool can be ele-

vated and lowered, respectively, by means of hydraulics. Such a three-point con- nector may be appropriate to use, but other types of actuators are also fully feasi- ble.

The example illustrated in figure 3 depicts an application where the scarify- ing device is used on a motor grader utilised for clearing snow. The invention could also be used with other types of equipment having plough or grader-like devices which are utilised for clearing snow.

The motor grader illustrated in figure 3, which is intended to be moved in direction upwards in the figure, indicated by the arrow B, is equipped with a grader device 12 intended for clearing of snow, as well as a scarifying device 21 accord- ing to the present invention. The device, seen in enlargement in figure 4, com- prises a grader blade 13, which, when the motor grader is moving forwards, removes snow 4 found in the area in front of the grader blade. The grader blade is angled in order to move the snow towards the perimeter of the roadway. At the rear of the grader blade 13, viewed in the direction of travel, a scarifying device 21 is arranged. This scarifying device is at a distance behind the grader blade and is intended to tear up gravel and possible ice 7 being located in/at the road surface, behind the grader blade 13, and being exposed once the snow 4, which originally covers the road surface, has been removed by the grader blade 13.

The grader blade with the scarifying device thereof is illustrated in more detail in figure 3. The scarifying device 21 on the rear of the grader blade 13 is in principle designed in a similar manner as the scarifying device in figure 1, with the difference that it is attached at the rear of the grader blade. Thus, it comprises a number of scarifier members, situated at a distance from each other and including scarifier points 10 arranged in order to, during scarifying, abut against the road surface and to a certain extent penetrate the road surface in order to accomplish the effect intended. The scarifier points 10 are preferably rotatable around the lon- gitudinal axis thereof in order to achieve a good tearing-up effect on the road sur- face. Advantageously, they are also angled to the road surface, in a similar man- ner as in figure 1. The distance between the scarifier points and the tip of the grader blade is suitably of the magnitude of 15-40 cm, preferably 20-30 cm.

The holding device 4 for the scarifier members 6 is designed as in figure 1, and comprises a spring 11 for each scarifier point 10 and a common carrier device 8, which extends essentially parallel to the grader blade. This carrier device is in

turn attached to the rear of the grader blade by means of a plurality of transverse elements 9, which connect the carrier device 8 with the rear of the grader blade 13.

The transverse elements may suitably consist of stiff sheet metal plates.

According to a preferred embodiment, also here the scarifying device com- prises guidance members 12, e. g. in the form of plates, for guiding the torn-up material in a direction essentially perpendicular to the angled grader blade. Pref- erably the plate forms an angle of about 90° to the grader blade.

In figure 5, a device is also seen including an actuator 15 by means of which the grader blade may be inclined at different angles to the roadway. By the way of inclining the grader blade forwards, the scarifying device will be lifted off the roadway and scarifying is discontinued, which is an advantage when the device is intended to be utilised for clearing snow on paved roads. The necessity of having to exchange or remove the scarifying device, which implies a heavy and laborious work, frequently in cool and wet weather conditions, is then avoided, and it is pos- sible to proceed the operation of clearing of snow by the same motor grader, only utilising the grader blade.

It is also feasible to make sure of positioning the grader blade and the scarifier members at different heights over the roadway at snow clearing/scarifying.

This may, for instance, be effected by adjusting the inclination of the blade by means of the actuator. In this case, usually it is made sure of setting the grader blade somewhat higher than the scarifier points.

The present invention should not be regarded as limited to the illustrated embodiment example, but may be varied and modified in a multitude of ways, within the scope of the appended claims.