The present invention relates to an apparatus for shaping a snow course, particularly so-called half-pipe used in snow-boarding on the faces of a piste.

This task is conventionally accomplished by means of mo¬ vable equipment intended for working and servicing skiing pistes, typically a snow course maintenance tractor which is a self-actuated vehicle moving on wide tracks. Such a vehicle is provided with a power outtake, and standard¬ ized implement links can be attached to it for operating different accessories and implements. For shaping a snow course, to the links is conventionally attached a shovel- ling scraper which is contoured to shape the snow course to a desired cross section. Snow-boarding is convention¬ ally carried out in a half-pipe having its walls circu¬ larly shaped with a radius of curvature of approx. 3 - 4.5 m. The width of the flat bottom area between the curved walls may vary in the range 5 - 20 m.

Drawbacks of equipment with a conventional construction include problems related to the heavy weight of the equipment resulting from the forward cutting operating principle which requires an enormous pushing capacity from the equipment. Hence, the equipment must be dimen¬ sioned to cope with the stresses imposed on the parts of the machine. Moreover, shaping of a half-pipe using such equipment is cumbersome as the snow course inclination varies according to the moguls of the course terrain.

A further problem in the maintenance of a half-pipe using conventional embodiments arises from the need of snow replenishment. When the walls of the half-pipe become worn with grooves through use, conventional equipment can remove such grooves only by cutting away snow from the walls of the half-pipe down to the bottom of the groove. While this may be possible with a sufficiently thick snow wall, in many cases snow replenishment to the walls is

necessary to achieve a satisfactory result.

An essential improvement over the above-mentioned draw¬ backs hampering the construction and function of prior- art equipment is achieved by means of the apparatus ac¬ cording to the present invention, the essential charac¬ terizing properties of the apparatus being disclosed in the annexed claim 1. Additional characteristics of the invention are defined in the dependent claims.

In the following, the invention will be explained in greater detail by making reference to the appended draw¬ ings in which

Figure 1 is a view of an apparatus according to the in¬ vention as seen in its intended working direction;

Figure 2 is a top view of the working section of the ap¬ paratus; and

Figure 3 a perspective view of the scraping element of the apparatus.

Referring to the drawings, the apparatus according to the invention is constructed supported by a lattice framework 2 and is designed mountable its attachments 1 to an ap¬ propriately moving self-actuated vehicle. Advantageously, such a self-actuated vehicle is the above-mentioned main¬ tenance machine of skiing courses.

Over the working section of the apparatus, said framework 2 is designed into a curved guidance path 2' incorporat¬ ing suitable supports and guides for the power-actuated movement of a flexible drive means such as two parallel running chains 3. The guides may comprise guide rolls and slide surfaces in a conventional manner. The parallel chains 3 are formed into an closed loop driven by a drive

unit actuated by a hydraulic motor 9.

To the parallel chains 3 are attached a plurality of scraper members 4 which project outward from said chain and arranged into a row along the movement direction of the chains. The scraper members 4 form the actual tool elements of the apparatus, and their structure and func¬ tion will be explained in greater detail later in the text.

The framework 2 is advantageously connected to the sup¬ port links 1 so that the apparatus can be turned in the vertical plane to different angles of inclination. Furt¬ hermore, the apparatus may be equipped with arrangements facilitating swinging of the apparatus from one side of the self-actuated vehicle to the other side for the pur¬ pose of shaping both walls of the half-pipe during a uni¬ directional run of the vehicle, e.g., downhill the cour¬ se. In a similar manner, the apparatus may advantageously be turned to different angles with respect to the propa¬ gation direction of the vehicle, either reaching slightly forward, or alternatively, to a backward lagging angle. Obviously, the apparatus may be attached in an equivalent manner to the rear of the vehicle, whereby the vehicle may even have one apparatus working one wall in front of the vehicle, while a second apparatus is mounted to the rear of the vehicle for working the other wall of the half-pipe.

Referring to Fig. 3, the scraper element 4 designed for use in the apparatus is here shown in greater detail. In the illustrated embodiment, the scraper element is pro¬ vided with a base plate 5 equipped with suitable attach¬ ments for fastening onto said drive chains 3. The base plate is aligned crosswise with respect to the movement direction of the chains. To the base plate is attached a cutting blade 6 spaced at a distance from the base plate

5 in a perpendicularly outward direction from the loop of the drive chain so that a gap will remain between the blade 6 and the base plate 5. Additionally, the scraper element includes a shove plate 7 located at the rear of the scraper element relative to the working direction of the element. The primary function of the plate 7 is to push snow cut away by the blade 6 upward along the curved wall of half-pipe and further over the edge of the half- pipe, where it remains available for subsequent mainte- nance sessions. The shove plate 7 is still followed by a smoothing element 8 adapted to sweep over the worked snow surface, thus serving to fill depressions on the surface of the half-pipe with snow detached by the blade so fin¬ ishing the smoothing effect accomplished by the plate 7.

In the illustrated embodiment, the scraper element 4 in¬ cludes a two-part blade 6. The first part thereof, the bottom part 6* is aligned parallel with the base plate 5 thus serving to work the surface of the curved wall being shaped by way of cutting along said surface. To one end of this bottom part 6' of the cutting blade is angled perpendicularly a second cutting blade part 6 ^M , later called the tip blade. This tip blade is aligned in the working direction of the apparatus, and its function is to perform vertical cutting-away along the edge of the slice to be removed from the snow wall.

A scraper element thus shaped is obviously suitable for a unidirectionally moving apparatus only. To permit bidi- rectional operation of the apparatus, the scraper element design must be modified accordingly by, e.g., angling a tip blade 6" to both ends of the cutting blade 6'. Simi¬ larly, an appropriate design of the shove plate 7 is required to smoothing in both directions with the use of a bidirectionally operating shaping apparatus.

For further finishing of the smoothing result, the appa-

ratus may further include sweeping apron plates made from a resilient sheet material that are attached to the rear edge of the curved part of the framework 2.