Abstract:
A cable transportation system ( 1 ) having a pull cable ( 2 ) defined by a number of strands ( 7 ) and drawn along a path (P); at least one transportation unit ( 3 ) movable along the path (P) and connected to the pull cable ( 2 ) by a coupling device ( 4 ); a metal structure ( 5 ) located along the path (P) to support and guide the transportation unit ( 3 ); and at least one guide roller ( 6 ) for guiding the pull cable ( 2 ) and supported by the metal structure ( 5 ) by means of leaf springs ( 26, 27, 40 ) which damp vibration caused by the strands ( 7 ) of the pull cable ( 2 ) contacting the guide roller ( 6 ).

Description:
PRIORITY CLAIM 
       [0001]    This application is a national stage application of PCT/EP2008/064491, filed Oct. 24, 2008, which claims the benefit of and priority to Italian Patent Application No. MI2007A 002071, filed on Oct. 26, 2007, the entire contents of which are incorporated herein. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates to a cable transportation system. 
         [0003]    More specifically, the present disclosure relates to a cable transportation system comprising a pull cable defined by a number of strands and drawn along a path; at least one transportation unit movable along the path and connectable to the pull cable by a coupling device; a metal structure placed along the path to support and guide the transportation unit; and at least one pull cable guide roller supported by the metal structure. 
       BACKGROUND 
       [0004]    Known cable transportation systems are substantially rail-mounted that extend along paths with bends and varying in height. 
         [0005]    For example, a cable transportation system is described in European Patent No. 0 687 607 B1. Guiding the pull cable around bends and along different heights calls for guide rollers that are normally supported by a normally concrete foundation structure. 
         [0006]    Sometimes, however, the path comprises portions with no foundation, as in the case of bridges. In these situations, the guide rollers must be connected to the metal structure of the bridge or to the rails themselves. 
         [0007]    This technical solution may pose various environmental problems, on account of the noise generated by the metal structure. 
         [0008]    This drawback may also prevent development of cable transportation technology in urban environments, as, for example, along elevated metal structures. 
       SUMMARY 
       [0009]    It is an object of the present disclosure to provide a cable transportation system configured to eliminate certain of the above-described drawbacks of known cable transportation systems. 
         [0010]    According to the present disclosure, there is provided a cable transportation system, characterized in that the guide roller is connected to the metal structure by leaf springs which reduce or dampen vibration caused by contact between the strands of the pull cable and the guide roller. 
         [0011]    Additional features and advantages are described in, and will be apparent from, the following Detailed Description and the figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    A number of non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying drawings, in which: 
           [0013]      FIG. 1  shows a partly sectioned front view, with parts removed for clarity, of a cable transportation system in accordance with the present disclosure; 
           [0014]      FIG. 2  shows a larger-scale, partly sectioned view in perspective, with parts removed for clarity, of the pull cable of the  FIG. 1  system; 
           [0015]      FIG. 3  shows a larger-scale view in perspective, with parts removed for clarity, of a detail of the  FIG. 1  cable transportation system; 
           [0016]      FIG. 4  shows a partly sectioned front view, with parts removed for clarity, of a variation of the present disclosure; and 
           [0017]      FIG. 5  shows a larger-scale, partly sectioned front view, with parts removed for clarity, of a variation of the  FIG. 1  transportation system. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Referring now to the example embodiments of the present disclosure illustrated in  FIGS. 1 to 5 , number  1  in  FIG. 1  indicates a passenger cable transportation system. In the  FIG. 1  example, cable transportation system  1  comprises a pull cable  2  drawn at substantially constant speed along a path P; at least one transportation unit  3  connectable selectively to pull cable  2  by a coupling device  4 ; a metal structure  5  for supporting and guiding transportation unit  3 ; and at least one guide roller  6  for guiding pull cable  2  and supported by metal structure  5 . 
         [0019]    With reference to  FIG. 2 , pull cable  2  extends along an axis A 1 , and is defined by a number of strands  7  twisted about axis A 1 . Each strand  7  is in turn defined by a number of metal wires  8  twisted about a non-metal core  9 , with the result that pull cable  2  has an outer surface  10  characterized by successive dips and ridges at regular intervals. 
         [0020]    With reference to  FIG. 1 , transportation unit  3  comprises a frame  11 ; two supporting wheels  12  resting on metal structure  5 ; two control wheels  13  controlling wheels  12 ; and coupling device  4 , which comprises a clamp  14  for selectively connecting and releasing transportation unit  3  to and from pull cable  2 , as described in detail in European Patent Numbers 1 077 167 B1 and 0 687 607 B1. 
         [0021]    In another embodiment (not shown in the drawings), transportation unit  3  is fixed to pull cable  2  by a non-releasable clamp (i.e., as typically employed in a back-and-forth transportation system). 
         [0022]    Metal structure  5  comprises two beams  15  substantially parallel to path P and defining construction members of a complex elevated structure; and two further beams  16 , each substantially parallel to path P and resting on a respective beam  15  by means of spacers  17  distributed along path P. In other words, further beams  16  define the rails on which transportation unit  3  rests. 
         [0023]    Guide roller  6  is connected to metal structure  5  by a frame  18  which, in the example shown, is fixed to beams  16 . In another embodiment (not shown in the drawings), frame  18  is fixed to beams  15 . 
         [0024]    Guide roller  6  rotates about an axis A 2 , and comprises an annular groove  19  for housing pull cable  2 ; and a pin  20 , of axis A 2 , supported rigidly by frame  18 . 
         [0025]    With reference to  FIG. 3 , frame  18  comprises two parallel cross members  21  crosswise to beams  15 ; a bar  22  ( FIG. 1 ) rigidly supporting pin  20  ( FIG. 1 ) and substantially parallel to beams  15 ; and two pairs of flanges  23  by which to fix bar  22  to cross members  21 . The position of flanges  23  with respect to cross members  21  is adjustable to adjust the tilt of bar  22  and therefore of axis A 2 , and to adjust the position of bar  22  in a direction parallel or crosswise to cross members  21 . Each cross member  21  comprises a central portion  24 ; and two end portions  25  connected telescopically to central portion  24  and fixed to central portion  24  by fasteners, such as screws. Each cross member  21  is longer than the distance between beams  15  and beams  16  (i.e., is longer than the distance between the rails). 
         [0026]    Each end portion  25  of cross member  21  is fixed to beam  16  by two leaf springs  26 ,  27  perpendicular to each other. In the  FIGS. 1 and 3  example, leaf spring  26  is substantially vertical and perpendicular to cross member  21 , and leaf spring  27  is substantially horizontal and parallel to cross member  21 . 
         [0027]    Leaf spring  26  has a first end gripped between the end of cross member  21  and a flange  28 ; and a second end gripped between a block  29  and a flange  30 . 
         [0028]    Leaf spring  27  has a first end gripped between block  29  and a flange  31 ; and a second end gripped between a bracket  32  and a flange  33 . Bracket  32  is C-shaped and connected rigidly to beam  16 . 
         [0029]    With reference to  FIG. 4 , each leaf spring  26 ,  27  is made of a number of packed spring steel plates  34 . 
         [0030]    With reference to  FIG. 3 , the length of each leaf spring  26 ,  27  is chosen as a function of the tilt of axis A 2  of guide roller  6 , and of the loads transmitted by pull cable  2  to guide roller  6 . The tilt of axis A 2  is in turn chosen as a function of path P of pull cable  2 . Using leaf springs  26 ,  27  of different lengths is made possible by frame  18 : both the length of cross members  21  and the position of guide roller  6  with respect to cross members  21  are adjustable. 
         [0031]    In certain embodiments, one of leaf springs  26 ,  27  may not be needed and may even be eliminated. 
         [0032]    In the  FIG. 5  variation, vertical leaf springs  26  are eliminated. 
         [0033]    More specifically, the embodiment of  FIG. 5  shows a frame  35  for supporting guide roller  6  positioned, in the example shown, with its axis A 2  horizontal and substantially crosswise to path P. Frame  35  comprises a cross member  36 ; a plate  37  for adjusting the height of guide roller  6 ; and an upright  38  integral with pin  20  of guide roller  6 . 
         [0034]    Cross member  36  is located beneath beams  16 , is equal in length to the distance between beams  16  (the rails), and has two ends, each of which is fixed to a respective flange  39  facing the underside of beam  16 , and is connected to beam  16  by a substantially horizontal leaf spring  40 . 
         [0035]    Leaf spring  40  is substantially parallel also to axis A 1  of cable  2 , and has one end fixed to flange  39  by a flange  41  and fasteners, such as screws, and one end gripped between a spacer  42  and a flange  43 . Spacer  42  is integral with a bracket  44  anchored to beam  16 . 
         [0036]    Leaf spring  40  is also made of packed spring steel plates  34 . 
         [0037]    Tests conducted by the Applicant show leaf springs  26 ,  27 ,  40 , made of spring steel (harmonic steel) plates  34 , reduce noise to such a relatively low level as not to cause harm or discomfort to people in the vicinity of cable transportation system  1 . 
         [0038]    It should be understood that various changes and modifications to the presently preferred embodiments described herein 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.