Patent Publication Number: US-2011049821-A1

Title: Multiple-position heel piece with easy engagement/release for Ski-touring bindings

Description:
The present invention relates to a multiple-position heel piece for ski-touring bindings. It is known in the technical sector of ski-touring that there exists the need to provide safety bindings which comprise a front member, or toe piece, able to clamp the toe of the boot, while allowing rotation thereof about a substantially horizontal axis, and a rear member, or heel piece, able to co-operate with the heel of the boot so as to allow three different modes of use, i.e.: release of the heel (walking mode); resting of the boot with greater/lesser inclination (uphill mode); and locking of the heel (downhill mode). 
     Also known, for example from EP 0,199,096, are bindings of the type described above which, however, have the drawback arising from the fact that the toe piece is without autonomous means for releasing the boot in the transverse direction, as required in the event of a fall or a twisting movement during descent, said safety function being performed by corresponding rear operating means of the heel piece which therefore has a very complex and heavy design, resulting in an assembly which has poor rigidity and is difficult to use. 
     The technical problem which is posed, therefore, is to provide a ski-binding heel piece which is able to perform:
         locking of the heel of the boot with the rigidity normally required for such applications;   improved locking of the heel with a reduction in the lateral play;   the possibility of assuming any one of the three operating configurations in a simple and rapid manner suitable for the conditions of use of said heel pieces.       

     In connection with this problem it is also required that this heel piece should be formed by a small number of small-size and low-weight parts which are easy and inexpensive to produce and assemble and can be easily applied to skis using normal standardized connection means. 
     These results are achieved according to the present invention by a heel piece for ski bindings according to the characteristic features of Claim  1 . 
    
    
     
       Further details may be obtained from the following description of a non-limiting example of embodiment of the subject of the present invention provided with reference to the accompanying drawings in which: 
         FIG. 1  shows an exploded view of the heel piece according to the present invention; 
         FIG. 2  shows a side view of the heel piece in the open position; 
         FIG. 3  shows a side view of the open heel piece during insertion of the boot; 
         FIG. 4  shows a side view of the heel piece in the closed position for downhill use; 
         FIG. 5  shows a side view of the heel piece in a first (low) position for raising the free heel so as to allow walking; 
         FIG. 6  shows a side view of the heel piece in a second (middle) position for raising the heel; and 
         FIG. 7  shows a side view of the heel piece in a third (high) position for raising the heel. 
     
    
    
     As shown in  FIG. 1  and with reference to a set of three axes, i.e. longitudinal axis X-X, transverse axis Y-Y and vertical axis Z-Z and the arrangements shown by way of example in the figures, conventionally assumed solely for the sake of convenience of the description, so that “front/inner” is regarded as being the part of the heel piece directed towards the boot and rear/outer as being the opposite part, the heel piece according to the present invention comprises:
         a fixed base piece  10  which is elongated in the longitudinal direction and is formed by a perimetral frame  11  which defines an inner seat  12  which is open in the vertical direction Z-Z; holes  14  with a vertical axis for fixing the base piece to the ski, not shown, by means of screws  14   a  are formed in the longitudinal arms  11   a  of the frame  11 .       

     Said inner seat  12  of the base piece forms a guide for:
         a slide  20  which is movable in both directions along the longitudinal axis X-X, following operation of conventional screw means  25  which, passing through the rear transverse side of the base piece  11 , cooperate with a nut  25   a  which is fixed to the slide itself so that rotation of the screw causes displacement of the slide.       

     The front of the slide has, formed therein, a seat  21  for housing lugs  22   a  of a step  22  covered by a reinforcing cover piece  23  which is fixed in position by means of a vertical screw  23   a  so as to allow the heel  1   a  of the boot  1  to rest thereon ( FIG. 3 ); it is also possible to insert spacers (not shown) between the step and the cover piece in order to adjust precisely the height of the heel; said housing seat  21  is also shaped so as to allow the step  22  to assume at least two stable positions in the longitudinal direction. 
     The rear part of the slide  20  is provided with a body  24  which has, formed inside it, a hollow cylindrical seat  26  suitable for housing resilient means  30  comprising a spring  31  which is fixed under compression inside the seat  26  between a top closing cap  33  with threading  33   a  which can be screwed into a female thread  26   a  of the seat  26  itself and a bottom shaped foot  32 . 
     Said body  24  also has longitudinal tracks  24   a  formed on the front surface of the said body and designed to form guides for corresponding roller wheels  113   a  associated with the front fork  110 ; said longitudinal tracks  24   a  have an inclination from the top downwards and from the rear towards the front and preferably at least one change in direction along their extension. 
     The shaped foot  32  has a through-hole  32   a  in the transverse direction designed to receive a cross-pin  34  which passes through the body  24  via respective substantially vertical eyelets  24   b  formed in the sides of the body itself. 
     By means of said pin  34  it is envisaged that a kinematic chain for transmitting the forces for operation of the heel piece is also is incorporated in the body  24 ; said kinematic chain comprises:
         a rear lever  120  which can be operated by the user and rotates on the pin  34 ;
           a front rotating fork  110  which is able to engage with the heel la of a boot  1  and in turn rotates on the pin  34 ;   
               

     In greater detail:
         the rear operating lever  120  is formed by a fork with parallel arms  121  which have respective transverse holes  121   a  through which the said pin  34  passes;   the front fork  110  is formed by two arms  111 , the front free end of which is formed in the manner of a hook  112  and the bottom end of which is pivotably mounted on the pin  34  by means of respective holes  113 ;   a connecting cross-pin  113  is arranged between said arms  111 , being inserted through corresponding holes  111   a;      which pin  113  carries two roller wheels  113   a  designed to roll on the corresponding longitudinal tracks  24   a  of the body  24 ;   a further pin  114  projecting transversely outwards and designed for insertion inside suitable respective shaped eyelets  122  in the arms  121  of the lever  120  is also present on each arm  111  of the fork  110 ;
 
closing in this way the kinematic chain which will transfer the movement from the operating lever  120  to the front fork  110 , as will emerge more clearly below with reference to operation of the heel piece.
       

     According to a preferred embodiment of the heel piece it is envisaged that the bottom end of the lever  120  is formed in the manner of a cam  123  consisting of a first surface  123   a,  substantially parallel to the longitudinal direction X-X, a second surface  123   b,  forming an obtuse angle with said first surface  123   a,  and a third surface  123   c,  forming an obtuse angle with said second surface  123   b.    
     Similarly the bottom end of the arms  111  of the fork  110  has a respective cam  115  formed by a first surface  115   a,  substantially parallel to the longitudinal direction X-X, a second surface  115   b,  forming an acute angle with said first surface  115   a.    
     With this configuration the operating principle of the heel piece is as follows:
         once the binding has been fixed to the ski and the desired height of the boot adjusted by means of the support piece  23 ,   after arranging the heel piece in the open configuration ( FIGS. 2 and 3 ), rotating the rear lever  120  downwards so that the front fork  110  is recalled upwards by the combined action of the pin  34  and the cams  123  and totally pulled towards the rear by the eyelets  122 ,   the heel  1   a  of the boot  1  is inserted into the heel piece ( FIG. 4 ) and the latter is closed by releasing the lever  120  which, pulled by the spring  31 , rotates upwards so that the upwards rotation causes the downwards travel of the roller wheels  113   a  along the tracks  24   a  which, as a result of their particular profile, produce a pressure such as to force the fork  110  to rotate towards the heel of the boot until the respective surfaces  123   a,   115   a  of the cams  123 , 115  of the lever  120  of the fork  110  assume a longitudinal position, resting on the base piece  10 ; in this position the hooks  112  engage with the pins lb of the boot and the heel piece is ready for downhill use;   in the event of different use of the binding for walking ( FIG. 5 ) it is possible to:   open the binding pressing the lever  120  downwards so as to cause retraction/rotation of the front fork  110  until the pins  1   b  of the heel  1   a  are released from engagement with the hooks  112 ,   extract the heel  1   a  and rotate again towards the front the lever  120  until the second surface  123   b  of the cam  123  is positioned parallel to the longitudinal axis X-X and rests on the base piece  10 ;
 
said operation of the lever  120  causes, via the eyelet  122  which acts on the pins  114 , the simultaneous rotation of the fork  110  which pivots downwards towards the front so as to position the second surface  115   b  of the cam  115  so that it is parallel to the longitudinal axis X-X and rests on the base piece  10 ; the rear surface  110   a  of the hook is thus made available for resting the boot thereon ( FIG. 5 ), the boot being retained only by the toe piece (not shown), while the heel  1   a  is free to be raised/lowered during the walking movement of the user;
   in the event of use for uphill walking on steeper slopes ( FIG. 6 ), the lever  120  is rotated towards the rear until the cam  123  and therefore the front fork  110  assumes the initial condition again, the cover piece  23  is pushed to the end of its travel towards the rear, creating a raised support surface on which the hooks  112  of the arms  111  rest; in this position the heel  1   a  of the boot rests on the convex upper surface  110   b  of the hooks  112 ;   if it is required to use the heel piece for even steeper slopes the lever  120  can be rotated ( FIG. 7 ) towards the front until the third surface  123   c  of the cam  123  is positioned parallel to the longitudinal axis and rests on the base piece  10  and therefore the front fork  110  is pivoted down towards the front; in this position the lever  120  stably presses against the base piece  10  and rests on the arms  111  and the heel la of the boot rests on the free end of the lever  120 , causing a greater inclination of the boot itself, particularly favourable for steeper slopes.       

     Safety release of the heel piece during downhill use is performed as per the following sequence:
         the pulling force exerted by the boot  1  on the hooks  112  of the fork  110  causes the latter to move upwards again and then rotate towards the rear against the pushing force of the spring  31  on the pin  34  and guided by the roller wheels  113   a  which roll along the tracks  24   a,  causing as a result disengagement of the hooks  112  from the pins of the boot which is thus free to separate from the ski.       

     It can therefore be seen how the heel piece according to the present invention, while ensuring a high degree of rigidity and absence of play in the transverse direction compared to the bindings known in the art, forms an assembly with a small number of component parts which is particularly light and simple to use, allowing a fast change in configuration by means of the rear lever which may also be operated using the ski stick, without the user having to bend over, this solution being particularly useful in the conditions of use which are typical of ski touring. 
     In addition, the heel piece according to the invention incorporates the vertical release system which is provided by the backwards/rotational action of the heel piece, said action in turn causing compression of the reaction spring, this vertical release representing an obvious advance in the ski-touring sector also in view of the simple design and lightness of the assembly.