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PRIORITY CLAIM 
       [0001]    This application is a national stage application of PCT/IB2014/066206, filed on Nov. 20, 2014, which claims the benefit of and priority to Italian Patent Application No. MI2013A 001925, filed on Nov. 20, 2013, the entire contents of which are each incorporated by reference herein. 
       BACKGROUND 
       [0002]    Normally, a snow tiller for preparing ski slopes is able to be drawn in a travelling direction along the ski slope, and comprises a supporting structure; and a shaft which is able to be rotated with respect to the supporting structure about an axis crosswise to the travelling direction, and is fitted with tools, each extending crosswise to the shaft axis. 
         [0003]    Certain large snow tillers have the drawback of failing to adapt to the contour of uneven snow surfaces. To eliminate this drawback, large articulated tillers have been devised, which are divided into sectors, each with a supporting structure and a respective shaft. The supporting structures are connected by hinges with axes substantially parallel to the travelling direction, and the shafts are powered by respective motors connected to respective ends of the shafts. 
         [0004]    In actual use, articulated tillers of the type described above are unable to work the part of the snow surface in the gap between the two supporting structures, thus resulting in relatively poor grooming of the ski slope. 
         [0005]    European Patent Document EP 0 287 897 discloses a flexible rotary snow tiller. 
         [0006]    SUMMARY 
         [0007]    The present disclosure relates to a snow tiller configured to prepare ski slopes. 
         [0008]    It is an advantage of the present disclosure to provide a snow tiller configured to prepare ski slopes which eliminates certain of the above drawbacks of certain of the known art. 
         [0009]    According to the present disclosure, there is provided a snow tiller configured to prepare ski slopes and able to be drawn in a travelling direction along the ski slope; the snow tiller comprising at least two supporting structures hinged to each other about at least one hinge axis; at least two shafts housed respectively in the supporting structures and able to be rotated about respective rotation axes crosswise to the travelling direction; tools fitted to the shafts; and at least one further tool connected at least to a shaft and located between the two supporting structures; wherein each shaft is supported by the respective supporting structure; the two supporting structures being coupled to each other by at least one articulated coupling enabling relative movement between the two supporting structures; wherein each shaft comprises a flange extending partly between the two supporting structures; and the further tool is fixed to one of the two flanges; the snow tiller comprising a blade which defines the further tool and is fixed directly to the one of the two flanges. In certain embodiments, the blade is fixed along the face of the one of the two flanges. 
         [0010]    By virtue of the present disclosure, the tiller adapts readily to the terrain, while at the same time ensuring more even grooming of the ski slope as compared with the known art, by virtue of the further tool. 
         [0011]    The articulated coupling enables the supporting structures to move and so adapt to the contour of the snow surface. 
         [0012]    In another embodiment, each supporting structure comprises respective bars; and a casing fixed to and supported by the respective bars. 
         [0013]    In another embodiment, the tiller comprises a supporting bar coupled to the supporting structures by further articulated couplings, so as to support the supporting structures and permit relative movements between the supporting structures and the supporting bar. 
         [0014]    The articulated couplings result in a structure that adapts readily to the contour of the snow surface and therefore of the underlying terrain, thus enabling better grooming of the snow surface. 
         [0015]    In another embodiment, the further articulated couplings are configured to permit relative movements between the supporting structures in a direction perpendicular to the travelling direction. 
         [0016]    In another embodiment, the tiller comprises a joint connected to the shafts and configured to permit relative angular movements between the shafts. 
         [0017]    In another embodiment, the further tool is mounted on the joint, such as at one end of the joint. 
         [0018]    In another embodiment, each shaft comprises a flange connected to the end of the joint; and the further tool is located on the joint and fixed to one of the two flanges. 
         [0019]    In another embodiment, the tiller comprises a blade defining further tools positioned 180° apart. 
         [0020]    In another embodiment, the blade has a hollow portion to permit assembly of the joint, and is fixed to one of the two flanges. 
         [0021]    In another embodiment, the tiller comprises a further blade defining another two further tools; the blade and the further blade being positioned at an angle of 90° to each other. 
         [0022]    The two blades at 90° to each other thus provide a tool every 90°, to ensure thorough grooming of the snow surface. 
         [0023]    Additional features and advantages are described in, and will be apparent from the following Detailed Description and the figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    A number of non-limiting embodiments of the present disclosure will be described by way of example with reference to the attached drawings, in which: 
           [0025]      FIG. 1  shows an underside view, with parts removed for clarity, of a snow tiller configured to prepare ski slopes in accordance with the present disclosure; 
           [0026]      FIG. 2  shows a larger-scale view in perspective, with parts removed for clarity, of a detail of the  FIG. 1  snow tiller; and 
           [0027]      FIG. 3  shows an underside view, with parts removed for clarity, of an alternative embodiment of the  FIG. 1  snow tiller. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Referring now to the example embodiments of the present disclosure illustrated in  FIGS. 1 to 3 , number 1 in  FIG. 1  indicates as a whole a snow tiller configured to prepare ski slopes and able to be drawn in a travelling direction D by a snow groomer vehicle (not shown in the drawings). 
         [0029]    Snow tiller  1  is used to till a surface layer of the snow covering, and comprises a frame F, of which  FIG. 1  shows a supporting bar  2  extending parallel to an axis A 1  and crosswise to travelling direction D; two supporting structures  3  and  4  connected to supporting bar  2  by respective articulated couplings  5  enabling movement in a direction perpendicular to axis A 1 ; and two shafts  6  and  7  supported by respective supporting structures  3  and  4 . Shaft  6  extends along axis A 1 , and is coupled to supporting structure  3  to rotate about axis A 1 ; while shaft  7  extends along an axis A 2 , and is coupled to supporting structure  4  to rotate about axis A 2 . In  FIG. 1 , axes A 1  and A 2  are coincident. In actual use, axes A 1  and A 2  may not be coincident, depending on the contour of the snow surface tiller  1  is working on. Tiller  1  also comprises a finish mat  8 , which is normally flexible, is connected to supporting structures  3  and  4 , extends behind shafts  6  and  7 , and is drawn over the tilled snow surface. 
         [0030]    Each supporting structure  3 ,  4  comprises two bars  9 ,  10  parallel to respective axis A 1 , A 2 ; and articulated couplings  5  fixed to one bar  9 ,  10  to connect it to supporting bar  2  of frame F. 
         [0031]    Supporting structure  3  comprises a casing  11 . More specifically, casing  11  is in the form of an arc-shaped plate fixed crosswise to the two bars  9 . Supporting structure  3  also comprises two supporting plates: an outer supporting plate  13  and inner supporting plate  14 , which are fixed to the ends of the two bars  9 . 
         [0032]    Likewise, supporting structure  4  comprises a casing  12 . More specifically, casing  12  is in the form of an arc-shaped plate fixed crosswise to the two bars  10 . Supporting structure  4  also comprises two supporting plates: an inner supporting plate  15  and outer supporting plate  16 , which are fixed to the ends of the two bars  10 . 
         [0033]    Shafts  6  and  7  are fixed to respective supporting plates  13 ,  14  and  15 ,  16  by bearings (not shown in the drawings). 
         [0034]    Tiller  1  comprises a joint  17  configured to connect shafts  6  and  7 ; and articulated couplings  18  fitted to and between, to connect, inner supporting plates  14  and  15 . 
         [0035]    Supporting structures  3  and  4  are thus connected by articulated couplings  18 , which enable relative movements of supporting structures  3  and  4  about a hinge axis A 3  parallel to travelling direction D. 
         [0036]    Joint  17  is configured to enable relative movements between shafts  6  and  7 . Joint  17  is a constant-velocity universal joint. More specifically, joint  17  enables movement between shafts  6  and  7  in a direction parallel to travelling direction D. And joint  17  is located between the two inner supporting plates  14  and  15 . 
         [0037]    Tiller  1  comprises a number or quantity of tools  19  fitted to shafts  6  and  7 . Each tool  19  extends crosswise to axis A 1  or A 2 . More specifically, tools  19  are defined by teeth  32  fixed to one of the two shafts  6  and  7 . Teeth  32  are configured to sink into and break up the snow surface. 
         [0038]    With reference to  FIG. 1 , shafts  6  and  7  comprise respective hollow cylinders  20  and  21 . Shaft  6  comprises two end flanges  22 ,  23  connected to opposite ends of hollow cylinder  20 ; two flanges  24 ,  25  integral with end flanges  22 ,  23  respectively; and seats  26  equally spaced along hollow cylinder  20  to house respective tools  19 . Flanges  24  and  25  are fitted respectively to supporting plates  13  and  14  of supporting structure  3  by bearings (not shown in the drawings). 
         [0039]    Likewise, shaft  7  comprises two end flanges  27 ,  28  connected to opposite ends of hollow cylinder  21 ; two flanges  29 ,  30  integral with end flanges  27 ,  28  respectively; and seats  26  equally spaced along hollow cylinder  21  to house respective tools  19 . Flanges  29  and  30  are fitted respectively to supporting plates  15  and  16  of supporting structure  4  by bearings (not shown in the drawings). 
         [0040]    Flanges  25  and  29  are also connected to joint  17 . Flanges  25  and  29  each extend partly between supporting structures  3  and  4 . More specifically, flanges  25  and  29  each extend partly between supporting plates  14  and  15 . 
         [0041]    Tiller  1  comprises four tools  19   a  on and on opposite sides of joint  17 . The four tools  19   a  are located between supporting structures  3  and  4 , and more specifically between supporting plates  14  and  15 . 
         [0042]    Tools  19   a  are defined by the appendixes of two blades  31  in the form of a rhomboid truncated at its acute angles. Blades  31  each have a hollow portion to permit assembly of joint  17 , and are fixed to respective flanges  25  and  29  by bolts  40 . In other words, each blade  31  is fixed directly to respective flange  25 ,  29  by bolts  40 . More specifically, each blade  31  is fixed along a face of respective flange  25 ,  29 . Each blade  31  forms two tools  19   a  at 180° to each other. And the two blades  31  are positioned at a 90° angle to each other. 
         [0043]    In the example shown, shafts  6  and  7  are powered by respective electric motors (not shown in the drawings). In which case, joint  17  serves to synchronize the rotation speed of shafts  6  and  7 . 
         [0044]    In an alternative embodiment, shafts  6  and  7  are powered by one electric motor connected directly to shaft  6  or  7 . In which case, in addition to synchronizing the rotation speed of the two shafts, joint  17  also transfers rotation from the shaft powered directly by the electric motor to the other shaft. 
         [0045]    Number  101  in  FIG. 3  indicates another embodiment of the tiller. All the parts of tiller  101  in common with tiller  1  are indicated using the same reference numbers. In this embodiment, joint  17  is omitted. So, the speed of shafts  6  and  7  is synchronized by a control unit controlling the motors (not shown) of shafts  6  and  7 . Moreover, as opposed to blades  31  defining tools  19   a , tiller  101  comprises blades  131  defining tools  119 . Tools  119  are connected to respective shafts  6  and  7  and located between supporting structures  3  and  4 . In certain embodiments, tools  119  are four in number: two connected to shaft  6 , and two to shaft  7 . The two blades  131  are fixed respectively to flanges  29  and  25 . In other words, each blade  131  is fixed directly to a respective flange  25 ,  29 . More specifically, each blade  131  is fixed along a face of respective flange  25 ,  29 . 
         [0046]    By virtue of tools  19   a  or  119 , snow is groomed substantially evenly over the whole longitudinal extension of tiller  1 . 
         [0047]    By virtue of the present disclosure, tools  19  and  19   a  or  119  are more or less equally spaced along axes A 1  and A 2 . 
         [0048]    In an embodiment not shown, there are more than two shafts, more than two supporting structures, and more than two hinge axes. 
         [0049]    Clearly, the present disclosure also covers embodiments not described in the above detailed description, as well as equivalent embodiments, which nevertheless fall within the protective scope of the attached Claims. That is, various changes and modifications to the presently disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.

Summary:
A ski slope snow tiller configured to travel in a travelling direction along the ski slope; the snow tiller having two supporting structures hinged to each other about a hinge axis; two shafts housed respectively in the supporting structures and configured to rotate about respective rotation axes crosswise to the travelling direction; tools fitted to the shafts; and at least one further tool connected at least to a shaft and located between the two supporting structures.