Patent Publication Number: US-2007114762-A1

Title: Device for fastening a sports boot to a board for gliding

Description:
BACKGROUND OF THE INVENTION  
      The invention relates to a device for fastening a sports boot to a board for gliding, particularly suited for cross-country skiing or ski hiking, i.e. allowing a rotation of the boot about a pin located toward the front of the boot. It also relates to a board for gliding as such, equipped with a device of this type.  
      A binding of this type has to fulfill two conflicting requirements: 
          on the one hand, it has to allow maximum progression of the foot toward the front, in order to offer a wide amplitude of movement in “conventional” cross-country skiing;     on the other hand, it has to allow optimum control of the ski when skating, which requires maximum contact of the foot on the ski for proper control of the latter and in order to limit the risks of the boot twisting relative to the ski.        

     DESCRIPTION OF THE PRIOR ART  
      A first family of prior-art solutions in response to these requirements consists in a beam mounted movably on the ski and having fastening means for receiving a boot sole, the anchorage of the boot extending over a zone delimited by the front of the sole and a rear limit located to the front of the metatarso-phalangeal joint. The majority of such solutions are based on an anchorage of the sole of the boot via two pins arranged under the sole and interacting with two anchorage means of complementary form arranged on the movable beam. The advantage of such solutions is their robustness and their effectiveness in controlling the ski. Documents FR 2 642 980 and FR 2 719 229 describe such solutions, in which the beam is mounted movably in rotation on the ski about a horizontal and transverse pin. However, they present the drawback of being highly complex since a number of parts and springs are required on the beam, in particular for implementing the functions of locking and unlocking the sole of the boot.  
      Other solutions propose beams provided with more complex movements than a simple rotation, or with more complex forms in order to improve the transmission of the forces. For example, documents WO 9637269 and WO 0013755 propose such solutions. These are even more complex and expensive to implement. Furthermore, they propose complex solutions for attaching and detaching the boot. In response to this latter problem, document EP 1 388 356 proposes a solution based on a beam provided with anchorage means allowing a simpler step-in-type attachment mechanism. However, in spite of everything, the construction proposed is still complex.  
      The second family of prior-art solutions is based on a solution in which the boot is fastened in its front part to a first fastening means, which allows good progression for the boot. A separate means for controlling the ski is provided. In order to fulfill this second function, a first solution is based on a guide edge arranged over a significant part of the length of the boot, combined with an elastic return means arranged on the front of the device, consisting of a block of deformable material, known as Flexor, in order to tend to push the boot back against the ski. However, this first solution is bulky at the front of the binding, which impedes progression of the foot, and control of the ski is unsatisfactory when skating. A second solution described in document FR 2 739 788 is based on a second anchorage of the boot at a point further to the rear, via a rod that fulfills the two functions of control and elastic return of the boot. This second solution improves control of the ski but adds bulk and complexity in the rear part of the device. These solutions of the second family are simpler than the preceding solutions of the first family, but they nevertheless present the drawbacks mentioned above.  
     SUMMARY OF THE INVENTION  
      An object of the present invention thus consists in proposing a novel device for fastening a boot to a board for gliding that does not present the drawbacks of the prior-art solutions.  
      More precisely, a first object of the present invention consists in proposing a simplified device for fastening a boot to a board for gliding that nevertheless meets the requirements of progression of the foot and control of the ski.  
      A second object of the present invention consists in proposing a fastening device for which the attachment and detachment mechanism is simple and user-friendly.  
      The concept of the invention makes it possible to define a family of fastening devices half-way between the preceding two families, based on two distinct elements for linking to the boot, one being movably mounted in rotation relative to the other, each comprising a jaw for fastening an anchorage means of the boot, the two means being given complementary movements enabling, at one and the same time, a boot to be locked/unlocked simply and in a user-friendly manner, good control and return of the boot over the ski, and optimum progression of the foot over the board for gliding.  
      More precisely, the invention is based on a device for fastening a sports boot to a board for gliding, comprising a first element for connecting to a boot, comprising a first jaw capable of fastening a first front part of the boot and a second element for linking to a boot, comprising a second jaw capable of fastening to a second part of the boot arranged to the rear of the first part in order to exert a control function on the board for gliding, the device also comprising a means for elastic return of the boot toward the board for gliding, wherein the two linking elements are distinct and movably mounted in rotation relative to the each other, the second linking element being linked to the fastening device in a zone arranged to the front of the position of the second jaw.  
      According to a first variant embodiment, the second element for linking to a boot is mounted movably in rotation on a base of the device, about a pin arranged toward the front of the device. It may have two arms provided at their ends with a hook forming the second jaw.  
      The second jaw of the device may be fastened to the second linking element and may have the form of a hook oriented toward the front of the device. It may have a sliding surface to promote the progressive positioning of the boot in this jaw in a phase of attaching a boot.  
      According to one variant embodiment, the first element for linking to a boot is mounted movably in rotation about a pin arranged toward the front of the device, which may be mounted on the base of the device. This pin may be the same pin as the rotation pin of the second linking element. In a variant embodiment, this pin may be mounted on the second linking element.  
      The first jaw of the device may be fastened to the first linking element. It may have the form of a hook oriented toward the rear of the device in the rest position and have a sliding surface to promote the progressive positioning of the boot in this jaw during a phase of attaching a boot.  
      According to another variant embodiment, the first linking element may comprise a surface or a lever suitable for its rotation toward the front in order to release the boot.  
      The means for elastic return of the boot toward the board for gliding may be a torsion spring mounted on a rotation pin of a linking element, acting, on the one hand, on the board for gliding or on a base of the device, and, on the other hand, on the first linking element. This torsion spring may act on the first linking element to tend to its rotation toward the rear of the device, bringing a surface to abut on a surface of the second linking element held in a longitudinal position in the rest position of the device.  
      The means for elastic return of the boot toward the board for gliding may fulfill a first function of elastic return and a second function of locking the boot.  
      The two linking elements may be substantially perpendicular in the rest position of the binding.  
      Lastly, the invention also relates to a ski as such, equipped with a device for fastening a sports boot, as defined above. 
    
    
     DESCRIPTION OF THE DRAWINGS  
      These objects, characteristics and advantages of the present invention will be set forth in detail in the following description of particular embodiments that are given in connection with the appended figures, without limitation, in which:  
       FIG. 1  shows a perspective view of the device according to a first embodiment of the invention, in its rest position on the ski;  
       FIG. 2  shows a side view of the fastening device according to the first embodiment of the invention;  
       FIG. 3  shows a perspective view of the fastening device of the first embodiment of the invention, in a slightly raised position;  
       FIG. 4  shows a perspective view of the fastening device in a slightly raised position according to a variant of the first embodiment of the invention;  
       FIGS. 5   a  to  5   c  show a side view of the fastening device according to the variant of the first embodiment of the invention, in intermediate phases of attaching a boot;  
       FIG. 5   d  shows a side view of the fastening device according to a second embodiment of the invention, when a boot is attached;  
       FIG. 6  shows a perspective view of the device according to the variant of the first embodiment of the invention, in its rest position on the ski in a phase of detaching a boot;  
       FIG. 7  shows a perspective view of the fastening device according to a second embodiment of the invention;  
       FIG. 8  shows a side view of the fastening device according to the second embodiment of the invention;  
       FIG. 9  shows a side view of the fastening device according to the third embodiment of the invention;  
       FIG. 10  shows a variant embodiment of the invention in which a Flexor is implemented. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      In order to make the following description simpler and to demonstrate that the concept of the invention may advantageously be implemented on existing cross-country ski boots, the following embodiments will be described within the context of a fastening device that is compatible with a ski boot comprising two metal pins for attaching under its sole, according to a standard known in the field of cross-country ski boots, the first pin being located toward the front end of the boot and the second, to the rear of the first, toward the zone of the metatarso-phalangeal joint of the foot. Naturally, the same concept of the invention is not dependent on a particular attaching means and could be adapted to different boots with other anchorage means.  
      FIGS.  1  to  3  illustrate a first embodiment of the invention. The fastening device comprises a base  20  mounted on a ski  10 . A first element  1  for linking to a boot is mounted movably in rotation about a pin  21  of the base and a second element  11  for linking to a boot is mounted movably in rotation about the same pin  21 .  
      The first linking element  1  comprises a first jaw  2  in the form of an arc of a circle, or a hook, the shape of which is adapted in order to receive the front pin of the sole of a cross-country ski boot. In the rest position of the binding, this arc of a circle is oriented substantially toward the rear of the board for gliding. Incidentally, the terms “front” and “rear”, in the case of the fastening device, will be used with reference to the front and the rear of the foot and of the ski. This linking element  1  also comprises an upper surface  3  adapted for manipulation as will be described in detail below, a lower surface  4  in contact with the second linking element  11  in certain positions of the device, and a sliding surface  5  for promoting attachment of the boot, as will be described in detail below.  
      The second element  11  for linking to the boot comprises a second jaw  12  of a form similar to the first jaw  2 , arranged at the end of two arms  13  of the linking element, the length of which allows this second jaw to interact with the second pin of the cross-country ski boot. This second linking element  11  further comprises a sliding surface  15  that is relatively stiff at the location of the jaw  12  in order to be involved in the mechanism for attaching a boot, two ends  16  of the arms  13  that surround the first linking element  1  in order to fasten the second element  11  on the same rotation pin  21  of the base  20  of the device. Lastly, it comprises a surface  14  that interacts with the surface  4  of the first element  1 , as will be explained below.  
      This fastening device also comprises an elastic return means that is not visible in the figures as it is implemented by means of a torsion spring positioned on the pin  21 , the functioning of which will be described in detail below.  
      The functioning of the fastening device will be described in more precise detail with reference to FIGS.  4  to  6  that show a variant embodiment provided with the same kinematics, which differs from the solution described above in that it comprises a lever  3 ′ for its manual actuation. This lever  3 ′ is mounted movably in rotation on a pin positioned in the upper part of the linking element  1 . It is free to rotate in the direction oriented toward the rear of the binding so as not to impede the progression movement of the foot. Thus, when the linking element  1  is turned toward the front of the device, after a raising of the foot, the lever  3 ′ enters into contact with the front surface of the ski or of the base of the binding and this contact gives rise to its rotation relative to the linking element  1 , without resistance and without impeding the movement of the latter in any way. On the other hand, a stop limits its rotation in the reverse direction, i.e. toward the front of the device. Thus, any force on the upper surface of this lever  3 ′, using a ski pole, for example, will have the effect of transmitting a significant force to the element  1 , generating its rotation toward the front of the device, by virtue of the lever-arm principle, which is useful, in particular, for detaching the boot from the grip of the first jaw  2 , as will be described in detail below. Aside from its contact with the ski or the base, this lever  3 ′ is advantageously held in its position against this stop illustrated in  FIG. 4  by a very lightweight spring (not shown).  
      As illustrated in  FIGS. 3 and 4 , the two linking elements  1 ,  11  of the fastening device, which are movable in rotation about the same pin  21  of the base  20  of the device, allow flanking of the movement of a boot when practicing cross-country skiing.  FIG. 4  illustrates the presence of the torsion spring  22  mounted on the rotation pin  21  of the linking elements and which acts on the linking element  1  in order to tend to its rotation toward its rest position, illustrated in  FIGS. 1 and 2 . This spring  22  is visible more particularly in  FIG. 8 , which corresponds to a second embodiment of the invention.  
       FIGS. 5   a  to  5   c  illustrate the mechanism for attaching a standard boot known from the prior art, comprising a first, front pin  31  toward the end of the sole of the boot and a second pin  32  arranged slightly in front of the limit of the metatarso-phalangeal joint of the user&#39;s foot. In these figures, only the two linking pins  31 ,  32  of the sole are shown, for reasons of simplification and clarity. Before attachment of the boot, the fastening device is at rest: the second linking element  11  is in the longitudinal position, bearing on the ski, the first linking element  1  is in a substantially vertical position, its lower surface  4  abutting against the surface  14  of the second linking element. The position of the two linking elements is maintained in this rest position stably, through the effect of the torsion spring  22 .  
       FIG. 5   a  illustrates a first method for attaching a boot, the first, front pin  31  of which is first of all positioned in the first jaw  2 . Next, the second pin  32  is lowered in contact with the sliding surface  15  of the second linking element  11 . The distance between the two jaws  2 ,  12  is such that lowering the boot on the board for gliding, generating sliding of the second pin  32  downward, generates a forward rotation of the first jaw  2  containing the front pin  31  through the force exerted by the foot, which opposes the spring  22 . When the pin  32  reaches the lower end of the sliding surface  15 , it automatically takes up a position in the second jaw  12  of the fastening device. At the same time, the first linking element  1 , released from the force exerted by the boot, resumes a less advanced position, through the effect of the spring  22 , reaching the final attaching position illustrated in  FIG. 5   d  described below.  
       FIG. 5   b  illustrates a second attaching method, in which the rear pin  32  of the boot is firstly positioned in the second jaw  12 , the first pin  31  sliding over the sliding surface  5  of the first linking element  1 , generating rotation of the latter toward the front under the weight of the foot until it takes up a position in the first jaw  2 , the fastening device then also reaching the position of  FIG. 5   d.    
      Lastly, a third method for attaching a boot is shown in  FIG. 5   c , in which the boot is lowered toward the device substantially horizontally until the two pins  31 ,  32  come into contact with the sliding surfaces  5 ,  15 , of the linking elements  1 ,  11 , respectively. In order to proceed with attaching the boot, the user continues to press his foot downward: this pressure from the boot creates a torsion force on the element  1 , which opposes the force exerted by the spring  22  and gives rise to its forward rotation, as illustrated in  FIG. 5   c , the second element  11  remaining immobile. In parallel, the pins  31 ,  32  are displaced downward, guided by the sliding surfaces  5 ,  15 , the rounded form and slope of which are provided for this purpose. When the pins reach the lower end of these sliding surfaces, they automatically take up position in the jaws  2 ,  12 , respectively, of the fastening device. At the same time, the first linking element  1  is freed from the force exerted by the boot and resumes a position more to the rear through the effect of the spring  22 , this movement at the same time generating locking of the pin  31  of the boot in the jaw  2 .  
       FIG. 5   d  thus illustrates the final position of the boot in the position of attaching by means of the fastening device of the invention. This figure corresponds to the second embodiment of the invention, the specific details of which will be explained below. The dimensions of the two linking elements  1 ,  11  are provided in order to correspond approximately to the spacing-apart of the pins  31  and  32  of the boot, the center distance between the two jaws  2 ,  12  in the rest position being shorter than the distance between the two pins  31 ,  32  of the boot, such that in the final attaching position the two jaws exert a continuous pressure on the pins of the boot. As shown in  FIG. 5   d , the result of this is that the first linking element  1  is not completely in its rest position, its surface  4  no longer arriving in abutment on the surface  14  of the second linking element  11 . This configuration guarantees locking of the boot. In fact, in this attaching position, the only possibility for the front pin  31  of the boot to be released from the first, front jaw  2  would be by means of its substantially longitudinal displacement toward the rear of the device. A displacement of this type is impossible on account of the second jaw  12 , in the form of a hook, oriented toward the front of the binding, which holds the second pin  32  of the boot and prevents a displacement of this type toward the rear. Similarly, the second pin  32  of the boot could not be released from the second jaw  12  other than by a displacement toward the front of the boot: in point of fact, a displacement of this type is prevented by the first jaw  2 , in the form of a hook, oriented toward the rear. Thus, the boot is properly attached and locked in the fastening device.  
      This device allows the raising of the heel of the boot, which gives rise to the rotation toward the front of the first linking element  1  about its pin  21 . This rotation also gives rise to the rotation of the second linking element  11  in the same direction, which thus, passively and independently of the first linking element  1 , follows the movement of the boot.  
      When practicing conventional cross-country skiing, this raising of the heel may take place without limit until the foot has progressed to the maximum extent, since there is no particular immobilization of the device thanks to its simplified configuration that offers no bulk. When the boot reaches a position of maximum raising of the heel, the spring  22  exerts a significant counterforce on the first linking element  1 , rotation of which toward the front has achieved a maximum position. This force of the spring then encourages the ski closer to the boot during the skier&#39;s opposite movement, tending to rest his foot on the ski.  
      When practicing skating, the second element  11  for linking to the boot allows optimum control of the ski when the boot is raised, in particular preventing twisting of the ski relative to the boot. Furthermore, the torsion spring  22  exerts a force between the ski and the first linking element  1  that gives rise to a return of the ski, in rotation, toward the boot. The spring  22  thus globally exerts an elastic return force, which tends to bring the ski and the boot closer together, thereby further enhancing the control of the ski during skating. Also provided is a groove/rib mechanism on the sole of the boot and the surface of the fastening device, in a manner known from the prior art, in order to improve this control of the ski when the boot is close to its surface.  
      In order to release the boot from the fastening device, its suffices to bear on the upper surface of the lever  3 ′ of the linking device  1 , for example using a pole, in the direction of the arrow B, as illustrated in  FIG. 6 , in order to generate rotation toward the front of this first linking element  1 , opposing the force of the torsion spring  22 , until the front pin  31  of the boot is released from the first jaw  2 . As soon as this pin  31  has been released, the movement of the boot toward the front and upward is possible, which then allows the release of the second pin  32  of the boot from the second jaw  12 . Thus, this mechanism offers the advantage of great simplicity and requires no complex manipulation, not requiring, for example, the skier to bend down toward the fastening device in order to manipulate it.  
       FIGS. 7 and 8  illustrate a second embodiment of the invention, which differs from the preceding embodiment in terms of the form of the linking elements  1 ,  11 . Functioning of the device, however, is still the same.  FIG. 8  shows, more precisely, the position of the ends of the spring  22 , an arm  23  of which acts on the front face of the linking element  1 , the other arm  23 ′ resting on the base of the device. The spring thereby exerts its return function between the linking element  1  and the ski.  
       FIG. 9  illustrates a third embodiment of the invention in which the two linking elements  1 ,  11  are given a rotation movement about two separate pins  21 ′,  21 ″, the first rotation pin  21 ′ of the first linking element  1  being mounted directly on the second linking element  11 , of which the second rotation pin  21 ″ is mounted on the base of the device and on which the torsion spring  22  is mounted, an arm  23  of which acts on the first linking element  1  as in the preceding embodiments. Other variant embodiments can be made in which the two linking elements are mounted in rotation one relative to the other, on the basis of a different arrangement. For example, the first rotation pin  21 ′ could be mounted on the base and the second rotation pin  21 ″ on the first linking element.  
      Lastly, the concept of the invention makes it possible to envisage a new family of solutions of devices for fastening sports boots on a board for gliding, which has numerous advantages that will be listed below and which, in particular, combines the advantages of each of the existing two families defined in the introduction. This concept has been illustrated within the context of standardized sports boots, but could be applied to any other standard for anchoring a boot.  
      The concept of the invention makes it possible to offer a solution that has the advantages of the first family of solutions of the prior art, based on a movable beam, as described. Replacing the complex beam of the prior art by two distinct, movable linking elements, two sorts of independent “simplified beams”, makes it possible to avoid the complexity of these known solutions with only one beam.  
      In a complementary manner, the concept of the invention also makes it possible to offer a solution that has the advantages of the second family of solutions of the prior art, in particular the solution described in document FR 2 739 788. Using a control means whose point of linking with the fastening device is placed to the front of its anchorage point with the boot allows a simplification of the function of control and an advantageous disassociation of the functions of control and elastic return.  
      This elastic return means has been shown in the form of a torsion spring mounted on the rotation pin of at least one linking element in the preceding embodiments, as this configuration offers the following numerous advantages: 
          this spring offers minimum bulk;     it makes it possible to predetermine a use orientation of the fastening device: e.g. a device designed, rather, for use in skating mode may be provided with a very stiff spring in order to exert a significant return of the ski, whereas a device designed more for conventional cross-country skiing may be provided with a more flexible spring, which promotes significant progression of the foot;     this spring in fact fulfills two functions in the preceding embodiments: it has the elastic return function mentioned above and is also an essential element in the locking of the boot. This combination of functions in a single element naturally allows the device to be simplified.        

      However, other return means, such as a spring acting on the second linking means, a Flexor arranged to the front of the device, a compression spring positioned on the front and/or a draw spring on the rear, or two return springs acting, respectively, on each of the two linking elements  1 ,  11 , the surfaces  4  and  14  no longer being of use in this latter configuration, could also be used without departing from the concept of the invention. The variant embodiment with Flexor is illustrated in  FIG. 10 , in which a Flexor  22 ′ acts on the first linking element  1  in order to tend to hold it in the rest position illustrated.  
      Lastly, the solution according to the invention satisfactorily fulfills the objects sought and offers the following advantages: 
          it is simple, since it is based on the following, few essential elements: a first linking element, linked, on the one hand, to the device, and, on the other hand, to a boot, comprising a first jaw fastened to this element, a second linking element that comprises, similarly, a second fixed jaw, a simple movement of these two elements, an element for elastic return of the device toward the rest position;     it guarantees good performance levels, for conventional cross-country skiing and for skating, control of the ski remaining optimum and progression of the foot significant;     it allows very simple attaching of a boot, of step-in type, and detachment that is simple and user-friendly, also;     it is compatible with existing boots.