ROTARY SNOW TILLER FOR GROOMING SKI SLOPES

TECHNICAL FIELD

The present invention relates to a rotary snow tiller for grooming ski slopes.

BACKGROUND ART

A rotary snow tiller for grooming ski slopes normally advances in a travelling direction, and comprises a frame; a shaft rotating about a first axis transverse to the travelling direction, and having teeth for breaking up the snow surface; and a protective casing surrounding the shaft.

Known rotary snow tillers of the above type have proved particularly effective in grooming ski slopes, but have several drawbacks, one of which is that the position of the shaft with respect to the snow surface

(tilling depth) can only be adjusted by moving the entire frame. Because the frame often supports other snow-working devices, movement of the frame also alters - in most cases, involuntarily - the position of the other devices, such as the finish mat.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a rotary snow tiller for grooming ski slopes, designed to eliminate the drawbacks of the known art in a straightforward, low-cost manner.

According to the present invention, there is provided a rotary snow tiller for grooming the snow

surface of ski slopes and designed to advance in a travelling direction, the rotary snow tiller comprising a frame; a shaft rotating about a first axis transverse to the travelling direction, and having teeth for breaking up the snow surface; and a protective casing surrounding the shaft; the rotary snow tiller being characterized by comprising an adjusting device for selectively adjusting the position of the shaft with respect to the frame. BRIEF DESCRIPTION OF THE DRAWINGS

A number of non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a partly schematic side view, with parts removed for clarity, of a rotary snow tiller, for grooming ski slopes, in accordance with the present invention;

Figure 2 shows a perspective view, with parts removed for clarity, of a variation of the Figure 1 rotary snow tiller.

BEST MODE FOR CARRYING OUT THE INVENTION Number 1 in Figure 1 indicates as a whole a rotary snow tiller for grooming the snow surface M of ski slopes, and which is towed in direction D by a snow groomer vehicle not shown in the drawings.

In the example shown in the attached drawings, rotary snow tiller 1 provides for tilling a surface layer of snow surface M of ski slopes, and comprises a

frame 2; a shaft 3 mounted to rotate with respect to frame 2 about an axis Al, and extending transverse to travelling direction D; a protective casing 4 surrounding shaft 3; a normally flexible finish mat 5 which is connected to casing 4, extends behind shaft 3, and is drawn over the surface of the tilled snow surface M; and an adjusting device 6 for adjusting the position of shaft 3 with respect to frame 2 and casing 4.

Frame 2 comprises a bar 7 parallel to axis Al; a hitch device 8 fixed to bar 7 and for connecting rotary snow tiller 1 to the snow groomer vehicle (not shown in the drawings) ; two arc-shaped segments 9 fixed to and transverse to bar 7; and two supporting bars 10 (only one shown in Figure 1) for supporting shaft 3. Rotary snow tiller 1 comprises two adjustable panels 11 which have the purpose to protect casing 4 and finish mat 5 from the snow thrown up by the groomer vehicle not shown in the drawings.

Shaft 3 comprises a number of teeth 12 equally spaced about and along axis Al, and each of which projects radially from shaft 3 to penetrate snow surface M.

The length of shaft 3 defines the work range and the width of rotary snow tiller 1 as a whole. Adjusting device 6 comprises two slides 13 (only one shown in Figure 1), each connected in sliding manner to a respective supporting bar 10; two further supporting bars 14, each arranged transverse to

supporting bars 10 and engaging in sliding manner a respective slide 13; and two blocks 15, each fitted to the end of a respective supporting bar 14 and connected in rotary manner to a respective end of shaft 3. In the example shown, one of blocks 15 supports a hydraulic motor 16 for rotating shaft 3 about axis Al.

Each slide 13 is connected to respective supporting bar 10 by an actuator 17 - which, in the Figure 1 example, is a double-acting hydraulic cylinder - and is connected to the respective further supporting bar 14 by a further actuator 18 - which, in the Figure 1 example, is also a double-acting hydraulic cylinder.

In actual use, rotary snow tiller 1 tills a surface layer of snow surface M by hydraulic motor 16 rotating shaft 3.

The depth of the tilled surface layer of snow surface M depends on the position of teeth 12 and shaft 3 with respect to snow surface M.

Adjusting device 6 provides for adjusting the tilling depth, without altering the position of frame 2 and casing 4, by simply activating actuators 18.

When the tilling depth is adjusted, the position of finish mat 5 therefore also remains unchanged.

Operation of actuators 17 moves shaft 3 in a direction parallel to travelling direction D, and provides for increasing or reducing recirculation of the tilled snow between casing 4 and shaft 3 for a given tilling depth.

In the Figure 2 variation, adjusting device 6 is replaced by an adjusting device 19, and supporting bars

10 of frame 2 are eliminated. Adjusting device 19 comprises two supporting plates 20 movable with respect to frame 2; and two arms 21 mounted to rotate with respect to frame 2 about an axis A2 parallel to axis Al.

Each arm 21 supports a respective supporting plate

20, and is operated by an actuator 22 connected to frame 2 and to arm 20. In the Figure 2 example, actuator 22 is a double-acting hydraulic cylinder.

Supporting plate 20 is mounted to slide along arm

21. In other words, arm 21 engages a guide 23 formed in supporting plate 20, which is movable selectively with respect to arm 21 by an actuator 24 which, in the Figure 2 example, is a double-acting hydraulic cylinder connected to arm 21 and to supporting plate 20.

Figure 2 only shows one supporting plate 20, one arm 21, one actuator 22, one guide 23, and one actuator

24. A hydraulic motor 25 is connected to shaft 3 and fixed to one of supporting plates 20 to rotate shaft 3 about respective axis Al.

In actual use, adjusting device 19 provides for adjusting the tilling depth, and for adjusting the position of shaft 3 in a direction parallel to travelling direction D, to reduce the distance between shaft 3 and casing 4 on the inlet side, depending on the rotation direction of shaft 3.

In other words, shaft 3 can be moved forward or back, for a given tilling depth of snow surface M, to adjust the distance between shaft 3 and casing 4 and so adjust the amount of snow recirculated between casing 4 and shaft 3.

This adjustment by adjusting device 19 is made possible by the system of polar coordinates centered about axis A2.