Abstract:
A mobile jaw ( 11,12 ) vice ( 10 ) for clamping and unclamping vehicles ( 19 ) to and from a traction cable ( 13 ) of a single-cable or two-cable transport system, such as a chair lift, a funicular cableway and a city transport system or a telpher, comprising a lever system ( 14, 15, 16 ) for arm ( 17, 18 ) and jaw ( 11, 12 ) handling, adapted to guarantee a suitable opening and an effective grip of the vice ( 10 ) onto the cable ( 13 ) also in case of wide oscillations of the vehicle ( 19 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Object of the present invention is a mobile jaw vice for clamping and unclamping vehicles to and from a traction cable of a transport system. 
     2. Description of the Background 
     The traction-cable rail transport systems currently known make use of synchronised braking or acceleration rollers of the vehicle (usually a cab) in the proximity of terminal or intermediate stations of a determined funicular route to be covered; a two mobile-jaw vice, connected to the cab floor, is used for unclamping the vehicle from the traction cable when the rollers decelerate the vehicle and, analogously, the jaws of the vice are driven so as to grip the cable when the run restarts and the vehicle is accelerated. 
     Nevertheless, the jaws used exhibit some disadvantages during the closing step, above all if the vehicle makes wide oscillations, due to the load or to dynamic stresses; in fact in this case also the traction cable may oscillate widely, thus significantly reducing the area of the portion of the grip synchronism. Moreover, the passage from the traction through cable to traction through draft wheels can cause serious defects, such as for example, pulsed stresses and excessive wear of the mechanical members on which the above cable can engage, in case the rollers are arranged in determined positions adapted to follow particular routes such as, for example, curvilinear and at the same time, rising trajectories. 
     SUMMARY OF THE INVENTION 
     Thus, an objective of the present invention is that of providing an improved mobile jaw vice for clamping and unclamping vehicles to and from a traction cable of a transport system, which should overcome the disadvantages mentioned above, that is to say, that of providing an improved mobile jaw vice which should allow attaining a firm and safe grip in all cases, also when the vehicle makes significant oscillations in vertical and horizontal direction, caused by the load variation due, for example, to the passengers&#39; boarding and getting off, or to external dynamic stresses. 
     Another objective of the invention is that of providing an improved mobile jaw vice for clamping and unclamping vehicles to and from a traction cable of a transport system, which should guarantee a substantially large symmetrical opening of the jaws with respect to the diameter of the traction cable. 
     Further objective of the present invention is that of indicating an improved mobile jaw vice which should allow creating a sufficient space for housing, in horizontal position, a cable-guiding roller so as to minimise the stresses to which the same cable is subject. 
     Said objectives are attained by an improved mobile jaw vice for clamping and unclamping vehicles to and from a traction cable of a transport system, according to claim  1 , to which reference shall be made for brevity. 
     Advantageously, the mobile jaw vice according to the invention allows arranging and orientating at will and need along the system, the cable-guiding line rollers so as to allow the guiding rail to cover any trajectory, such as for example, a curvilinear and rising or descent trajectory. 
     In this way, the cable is prevented from imparting undesired stresses to the cable-guiding rollers. Moreover, the particular arrangement of the cable-guiding rollers according to the invention guarantees a perfect guide of the cable and avoids an undesired and dangerous slipping out of the same. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of the invention will appear more clearly from the following description and attached drawings, relating to an exemplificative and non-limitative embodiment, wherein: 
     FIG. 1 shows a partly sectioned side view of an improved mobile jaw vice for clamping and unclamping vehicles to and from a traction cable of a transport system, according to the present invention, in working position; 
     FIG. 2 shows a partly sectioned side view of the vice of FIG. 1, according to the present invention, in unclamping position; 
     FIG. 3 shows a top view of the vice of FIG. 1, according to the present invention; 
     FIG. 4 shows an elevation view of the vice of FIG. 3, according to the present invention; 
     FIG. 5 shows a partly sectioned partial cross view of a funicular transport system with relevant vehicle, comprising an improved mobile jaw vice, with the several possibilities of arrangement of the cable-guiding rollers, according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the figures mentioned above, reference numeral  10  generically indicates a vice for clamping or unclamping vehicles  19  to a traction cable  13  of a transport system, in particular a funicular transport system, such as a fixed- or automatic-clamping cableway or funicular railway. 
     Vice  10 , provided with two mobile jaws  11 ,  12 , which grip or not cable  13 , is arranged on a same plane with respect to the axis of rotation of its driving rollers  40 , and it is fixed, in the lower side, to floor  20 , whereas each vehicle  19  is mobile on sprung wheels  45 , and is towed by cable  13 . 
     In particular, vice  10  comprises two mobile arms  17 ,  18  for driving the jaws, respectively  11 ,  12 , which are pivoted onto pivot  22 , at the end facing the traction cable  13 ; at the opposed ends, arm  17  is hinged in  23  to a first lever  15 , in turn hinged in  24  to a second lever  14 , which is pivoted in  25  to a box-shaped support structure  26  of vice  10  to vehicle  19 ; on the other hand, arm  18  is connected to a third lever  16  through a hinge  27 . 
     Finally, lever  16  is further connected to lever  15  through hinge  24 , so as to obtain an articulated structure similar to a pantograph. 
     Two further hinges  29  are connected to the box-shaped structure  26 , each connected to a helical spring  31  through a plate  30  adapted to make spring  31  rotate into a direction and into the opposed direction during the clamping and unclamping operations to and from cable  13 . 
     The helical springs  31 , pre-loaded in compression on a guide  37 , are arranged between a fixed thrust plate  33 , integral with the box-shaped structure  26  and hinged in  35  to arm  18  and to guide  37 , and a mobile thrust plate  34 , integral with plate  30 . 
     Arm  18  elongates in a curved structure  38  connected, through fastening means  39 , to the driving roller  40  through bearings  41 . 
     Moreover, it is provided that a portion of the curved structure  38  can be brought into contact with an abutment element  42 , fastened to the box-shaped structure  26 , in a rest position of the vice  10  when vehicle  19  is unclamped from the traction cable  13 , thanks to the fact that the driving roller  40  is forced to cover a trajectory on an inclined plane  21 . 
     With particular reference to FIG. 5, which relates to a portion of a funicular system where the vice  10  is used, according to the present invention, reference numeral  45  indicates the wheels of vehicle  19 , reference numeral  46  indicates the profile of the rail where vehicle  19  is constrained, reference numerals  47  and  48  indicate two positioning rollers, reference numeral  49  indicates a orientating trolley, fastened to floor  20  of the telpher of vehicle  19 , and reference numerals  50 ,  51 ,  52 ,  53  indicate the cable-guiding rollers, arranged along the line according to the requirements. 
     With particular reference to FIGS. 1 and 2, which respectively refer to a working or clamping position of the vice  10  to the traction cable  13 , and to a rest or unclamping position of jaws  11  and  12  of the vice  10  from cable  13 , it can be noted that the pantograph system of levers  14 - 16  allows such a movement as to obtain a substantially large opening of jaws  11 ,  12  with respect to the diameter of cable  13  to be clamped. In practice, using a helical spring  31  of the known type, the two jaws  11 ,  12  open concurrently, thus preventing said movement from causing any movement of cable  13 . 
     Moreover, the closing action in perfect synchronism of jaws  11 ,  12  onto cable  13  guarantees a safe grip of the cable with a suitable clamping force, since the area of the portion of the grip synchronism increases considerably with respect to the prior art. Finally, the arrangement of levers  14 - 16  and the substantially arched shape of arms  17 ,  18  of the vice  10  guarantee the creation of a suitable space, indicated in FIGS. 1-2 with reference numeral  65 , for housing the cable-guiding roller  50  (as it can directly be seen in FIGS. 2 and 5) in horizontal position. This is extremely useful for the purpose of avoiding the use of cable-guiding rollers in inclined position, which would thus be strongly stressed by cable  13 . The arrangement in horizontal position of the cable-guiding roller  50  further prevents the occurrence of stresses, always present in the case of cable-guiding rollers arranged in inclined position with respect to that horizontal, which tend to make cable  13  lift and slip from its seat. 
     The operation of the vice  10  according to the present invention is substantially as follows. 
     In the passage from a working position to an unclamping position, roller  40  is forced to follow the trajectory of the inclined plane  21 ; the direct consequence of this is the raising of the arched portion  38  up to touching support  42 . In this way, spring  31  substantially arranges itself in line with pivot or fulcrum  22 , thanks to the fact that arm  18  is parallel to guide  37 , along the imaginary axis passing through the hinging points  35 ,  27 ,  29 . 
     At the same time, point  23 , where arm  17  and lever  15  are constrained, moves towards point  29  of counter-clockwise rotation of spring  31 , thanks to the movement of plate  30 , whereas hinge  24  is not aligned any more with fulcrum  27  since it is forced to move rightwards. 
     As a consequence, since lever  14  is fastened to the box-shaped structure  26  into fulcrum  25 , as it rotates in a counter-clockwise direction with respect to the same fulcrum  25 , it will move to an almost horizontal position along the direction connecting the points  24  and  25 . 
     Moreover, there is provided a hole  60  into structure  26 , which is used for finely regulating the position of fulcrum  25 , which must necessarily be manufactured with very strict working tolerances, due to the stress to which it is subject during the clamping and unclamping operations of vice  10 . 
     Of course, in the case of passage from an unclamping position to a working position, the movements of arms  17 ,  18  and of levers  14 - 16  will be the same as described above, in a reverse order. 
     In this way, as it can be clearly seen in FIGS. 1,  2  and  5 , the obtained opening width of jaws  11 ,  12  is suitable for firmly and safely clamping the traction cable  13  in any condition of oscillation of the same. 
     In fact, the presence of the articulated pantograph, which transversally translates to the advancement direction of the traction cable  13 , causes a perfectly symmetrical drive of arms  17 ,  18 , thus realising a large opening of the jaws, a correct clamp, a suitable clamping force, and a sufficient space for arranging the cable-guiding roller in horizontal direction. 
     Finally, the vice  10  according to the invention can be structured without dead centre, or with dead centre; moreover, for safety reasons, it is preferred to provide each funicular vehicle  19  with at least two vices  10 , each forced to one of the end axles of vehicle  19 . 
     The above description clearly shows the features of the improved mobile jaw vice for clamping and unclamping vehicles to and from a traction cable of a transport system, which is object of the present invention, and it clearly shows its advantages. Finally, it is clear that several variants can be made to the improved vice, object of the present invention, without departing from the novelty principles of the inventive idea, and it is also clear that, in the practical implementation of the invention, materials, shapes and sizes of the illustrated details can be of any type according to the requirements, and the same can be replaced with others, technically equivalent.