Abstract:
A configuration contains a ski binding and a ski boot, whereby a sole of the boot is connected to the ski binding by a maintaining element and performs a rolling off movement when the heel is lifted. The maintaining element contains at least three fixed points, whereby at least one fixed point acts as a rotational point in the region of the ski when the ski boot is lifted, at least one second point is connected to the sole of the boot in the ball region, and at least one third point is provided in the region of the tip of the sole in order to couple the ski binding to the ski boot.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to an arrangement according to the classifying clause of claim  1 . 
     Cross-country ski bindings with rigid axes that are mounted to the boot and primarily fastened in the toe region while being pivotable about an axis located transverse to the ski by an articulated connection attached to the ski are known in various configurations. Such a configuration enables the front end of the ski boot to be secured to the ski during cross-country skiing or downhill skiing in the Telemark style, while the rear end of the ski boot can be freely lifted. A binding of this type is, for instance, known from EP 0 424 479. With that binding, a substantially flat boot sole is used. This is necessary in order to enable the pivotal point to be positioned near the sole contact zone. 
     It is generally known that flat boot soles are unsuitable for normal walking from an ergonomic point of view, since they prevent the natural rolling movement. 
     Another characteristic feature of such boot/binding systems also resides in that the boot sole, in the tip region, has a corner-shaped configuration which serves to receive the rigid axis of rotation anchored in the boot sole. During normal walking, that configuration is additionally inconvenient, since the rolling movement is effected about an unnatural tilting edge. 
     Configurations as are, for instance, known from PCT/EP84/00047 enable natural rolling movements during walking, yet the connection to the ski by means of a flexible, leaf-shaped connection is no longer state of the art, since the lateral and torsional stabilities required for cross-country skiing are no longer ensured. 
     An arrangement of the initially mentioned kind has become known from WO 01/93963. 
     That arrangement enables a rolling movement of the foot on the ski during skiing and also an anatomically correct rolling of the foot during normal walking. The drawback of that embodiment resides in the elaborate production of the system, involving high costs. In addition, the freedom of movement (lifting of the heel) in the proposed solution is limited by a damper element positioned below the tip of the boot. U.S. Pat. No. 6,209,903 B1 describes a fastening system to connect a boot with a ski and ensure a limited angle of aperture. The objective of the document is, thus, totally different from that of the present invention. Another characteristic feature of that document is that the rear engagement element has to be flexibly or at least elastically mounted, which results in an additional instability and increases production costs. 
     From FR 2 741 543, a connection has become known, which meets the demands placed on a boot sole that is correctly designed from an anatomical point of view. However, it involves the disadvantage of the connection being provided in the region of the metatarsophalangeal joint with a damper element provided below the toe region, which would likewise restrict the necessary heel lift. In addition, a cross-country skier will feel insecure at a rearward weight transfer, since the boot is not fixed below the tip of the toe. 
     BRIEF SUMMARY OF THE INVENTION 
     It is the object of the present invention to provide a favorable, yet stable connection to the cross-country ski in a boot sole configuration that is correct from an anatomical point of view, while avoiding the drawbacks of known constructions. 
     This object is achieved by the measure according to the characterizing clause of claim  1 . This is the simplest way to renounce complex and cost-intensive kinematics. It is based on a simple rotation about a fixed axis in the region of the tip of the boot, as it will be found as a standard in all current cross-country ski bindings. 
     Further advantages of the invention result from the measures according to claims 2 to 10. 
     The subject matter of the invention is also a cross-country ski boot for the binding according to the invention, which meets the orthopedic demands. 
     An exemplary embodiment of the arrangement according to the invention is illustrated in the attached drawings. 
     Therein, in a simplified illustration: 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a side view of a cross-country ski boot in which the principle of the connection between boot and binding is indicated; 
         FIG. 2  depicts a known embodiment of a cross-country ski boot having a boot sole part projecting in a corner-like manner; 
         FIG. 3  is a longitudinal section through the tip portion of the cross-country ski boot according to the invention, including a tenter hook; 
       FIGS.  4  and  4 . 1  are similar longitudinal sections in different positions of the cross-country ski boot, including a rotating hook as the tensioning device; 
         FIG. 5  illustrates the tip region of an embodiment of the boot sole; 
         FIGS. 6 to 8  depict further variants of the tip-side binding unit in an axial longitudinal section in the closed position, viewed from below, and in an axial longitudinal section in the opened position; 
         FIGS. 9 to 11 ,  12  to  14  and  15  to  17  each in illustrations similar to those of  FIGS. 6 to 8  depict further variants of the tip-side binding unit; and 
         FIG. 18  depicts a longitudinal section through a further variant of the tip-side binding portion. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     In the Figures, a cross-country ski boot is denoted by  1 , which is connectable with the ski on the side of the tip by a binding unit  2  ( FIGS. 3 and 4 ) which comprises at least three, in the present case three, fixed points  4 ,  5  and  6  forming a rectangular triangle having the fixed points  4 ,  5  and  6  in  FIG. 1 , yet this is not necessarily required. The proposed system is pivotable about the fixed point  4  serving as a pivot point, which, as in the present case, is preferably located in the corner of the imaginary triangle having the largest interior angle, i.e. 90° in the illustrated embodiment with a rectangular triangle. As shown in  FIG. 1 , the two legs are oriented from the pivot point in the direction towards the sole connection points. The hypotenuse is defined by the imaginary distance between the two sole connection points. The binding element, thus, virtually becomes a part of the boot sole during cross-country skiing. This part to be used for cross-country skiing, or the respective region of the sole including the pivot point near the sole/ski contact zone, offers the advantage over the cross-country ski boot sole including an embedded axis of rotation, as is presently common and illustrated in  FIG. 2 , that the sole portion used for cross-country skiing can be uncoupled for free walking and, hence will not impede the natural rolling movement. 
     An essential advantage of the proposed solution, however, resides in that the pivot point of the system can be provided below the sole/ski contact zone even without raising the standing position. This is of advantage because the rolling movement is the more easily feasible the deeper the pivot point, based on the sole/ski contact zone. 
     Another advantage of the proposed solution resides in that the pivot point, as a function of the construction, can be arranged both below the tip of the boot and some millimeters behind the same, in order to thus be able to exert further positive effects on the rolling movement during cross-country skiing. 
     The invention follows the basic idea that the function of normal walking without skis and the function of cross-country skiing with skis are separated from each other. The movement of the sole during walking without skis corresponds to a kinematics that combines rotation and translation movements, whereas the movement of the sole during cross-country skiing is realized by a simple rotation. 
     The connection point  5  in the ball region of the ski boot sole  7 , which will be described in more detail below, as well as the anchorage point  6  in the region of the ski boot tip for the connection of the cross-country ski boot  1  to the binding unit  2  are, at the same time, not rotation points, but merely serve to rigidly and hence stably connect the rotationally mounted binding unit with the boot sole  7 . 
     The binding element  2  is substantially comprised of three parts, namely the axis of rotation  4 ′ acting as a hinge, a front retaining element  9  as well as a retaining element not illustrated. The axis of rotation  4 ′ or hinge joint, respectively, which coincides with the pivot point  4 , can be firmly or detachably connected with the ski  3 . 
     The front retaining element  9 , by the aid of a commercially available tenter hook  10 , is latchable into a tip-side sole extension  11  devised as a step projecting from the tip side. 
     In a modified embodiment of the retaining element  5 , a hook  12  rotating about the axis of rotation  4  is provided as shown in  FIG. 4 , which hook is pressed against the sole extension  11 , preferably by a torsion spring  13 . The hook surface  14  is designed such that the binding can also be devised as a step-in binding. In order to facilitate this step-in function, it will be particularly advantageous, if the hook element  16  in the open state is kept at a distance from the upper surface of the ski by a defined measure x. 
     As illustrated in  FIG. 4.1 , this characteristic feature of the invention is achieved in that the hook element  16  is pressed away from the upper surface of the ski by a measure x, and held in that position, by a spring element  16 ′ which may be of any design, e.g. a torsion spring, a swivel spring or even a rubber-elastic component, for instance. 
     This will considerably facilitate the stepping into the binding by the boot  1  with its axis  17 , which moves into the sense of arrow A when stepping into the binding. 
     The length of the front retaining element  9  depends on the height of the outer toe spring  15 . The higher the outer toe spring  15 , the longer the front retaining element  9  must be designed. 
     As illustrated in  FIGS. 3 and 4 , the rear retaining element  16 , or rear connection, is realized by a hook element  16  which engages an axis  17  rigidly anchored in the sole side, preferably by an injection-molding technique, and corresponding with the initially mentioned connection point  5 . The hook element  16  is designed to be stiff or rigid, i.e. not flexible, and pivotable about the axis  4 ′. It comprises a bead  18  near the axis of rotation or hinge  4 ′, which serves to support the front sole surface located near the tip of the boot. This bead  18 , at the same time, provides a material compensation between the sole rounded by the outer toe spring  15 , and the rather plane upper surface  3  of the ski. Alternatively, the rear hook element  16  may also holohedrally contact the sole surface (without any specific bead formation). 
     While the hook  12 , in the embodiment according to  FIG. 4 , is pivotable about the hinge  4 , the tenter hook  10 , in the embodiment according to  FIG. 3 , is designed as a double-armed pivot lever which is connected with a lever  19  articulately connected to both ends between its longer arm, which is configured as an actuation lever, and its shorter arm, which is configured as a latch. Finally, the binding element  2  may, for instance, be equipped with a leg spring  20 , which dampens and/or delimits the pivotal movement of the boot sole. In accordance with the invention, said leg spring  20  may, at the same time, function as a torsion spring  13 . In that case, the function of pressing the rotating hook  12  and damping/delimiting the pivotal movement of the boot sole is taken over by a single engineering component. 
     The toe spring  15  is responsible for the boot sole to meet the orthopedic requirements, which means that the sole will still have a rounded shape starting from the ball contact point forwardly in the direction to the tip of the boot. 
     The longitudinal axis  17  is preferably located about 4 cm behind the tip of the boot and, as already mentioned, may be embedded in a groove extending transversely to the running direction by injection molding. The rear hook element  16  substantially extends from the pivot point or hinge  4 ′ in a longitudinally extending central groove as far as to the axis  17 , thus offering the advantage of the rear hook element being able to take up transverse forces via the abutting, lateral inner walls of the longitudinally extending central groove, which promotes a substantial stabilization of the overall system. 
     As illustrated in  FIG. 5 , the sole extension  11  may be equipped with a groove  21 , which, when hooked with the front retaining element  9 , is able to take transverse forces, thus serving to laterally stabilize the system. 
     The configuration according to the invention of the binding unit  2  does not require a raised standing position as opposed to presently used systems. 
     In the other illustrations of different embodiments of the tip-side binding unit according to  FIGS. 6 to 18 ,  30  serves to denote a base plate to be fastened to a ski, e.g. by screws, to which end the former comprises at least two, preferably three or four, holes  31 , which may be provided in any distributed manner. The base plate  30 , in its longitudinal center, comprises an upwardly extending projection  32  including a hole  33  extending transversely to the ski axis for receiving the axis  4  surrounding the spring  13  at least over a portion of its periphery. 
     In the embodiment according to  FIGS. 6 to 8 , a lever  34  is rotationally mounted on the axis  4  to carry the hook element  16 , which forms an angular pivot lever with a lever  34 . The hook element  16 , which serves to receive the boot axis, is made of edged spring steel sheet. The hook element  16  incorporates the spring  13  which encloses the axis  4 , preferably by 5¼ windings, and, in the resting state, presses the hook element  16  against the ski while biasing the same such that, at the step-in of the boot, a force will be exerted on the boot by the tip of the boot behind the undercut  35  of the lever  34 , thus holding the boot in the binding. Moreover, the spring  13  provides a resistance against the forward tilting of the skier during cross-country skiing when lifting the foot. The tilting angle in the present case is preferably 60°. 
     In the embodiment according to  FIGS. 9 to 11 , the hook element  16 , as opposed to the preceding embodiment, on its end facing away from the hook  12 , is provided with an arc  36  corresponding with the sole contour and chamfered on the end so as to form an angle  37  oriented towards the ski and including a hole  38  for inserting the ski pole to open the binding. The chamfer forming the angle  37  ensures lateral stability. This embodiment enables a narrow construction and offers the advantage of the retention force merely occurring from the material deformation of the spring steel sheet of the hook element  16 . This construction, moreover, ensures that the whole retaining and guiding mechanism can be received in the groove of the boot sole so as to be invisible. 
     In the variant according to  FIGS. 12 to 14 , the same principle as in the embodiment according to  FIGS. 6 to 8  is provided, wherein the axis  4 , if necessary, may be a rivet or screw piece to hold the binding together. Contrary to the two last-described variants, the hook element  16  forming the retaining mechanism in this case is made of a spring steel and bent upwards on its end side, thus spirally enclosing the axis  4  while forming the spring element  13 . This variant results in a stable construction, since a larger binding width is feasible. Moreover, its production is cost-saving, since the spring element  13  together with the hook element  16  will be supplied as a semi-finished product. The retention force is obtained by a material deformation of the hook element  16  when stepping into the binding, which is opened by inserting the ski pole into the depression  39  of the lever  34 . In order to prevent the skier from tilting over, a spring may be incorporated in the axis  4 , or a plastic part indicated in  FIG. 12  in broken lines may provided below the tip of the boot, which plastic part is comprised of a two-component injection-molding part, namely a very soft damping component and a hard boot-retaining component. 
     The variant according to  FIGS. 15 to 17  is substantially based on the same principle as the variant according to  FIGS. 9 to 11 , with the difference that the construction is devised such that it is not to be embedded in the interior of the groove of the boot sole, since it is designed to be wider for stability reasons. In this variant, the hook element  16  made of chamfered spring steel sheet is supported on the spring  13  above the axis  4  in the region of its outward bend which is provided on the end of the hook element  16  facing away from the hook  12  for receiving the retaining pin in the tip region of the ski boot sole. The guidance of the hook element  16  above the axis  4  ensures a particularly stable construction, by which the retention of the ski boot is obtained by the deformation forces of the hook element  16  and the tilting over of a skier is prevented by the incorporated torsion spring  13 . 
     The variant according to  FIG. 18  is based on the same principle as the variant according to  FIGS. 6 to 8  and represents a construction to be produced with little expenditure, wherein the same reference numerals are used for identical components. The difference from the described variants consists in that the hook element  16  with its hook  12  for retaining the axis of the boot tip and the lever  34  are mounted separately from each other, with the lever  34  being mounted so as to be pivotable about a stationary axis  41  and biased by a spring  42 , i.e. a torsion spring in the present case, in order to keep the boot in the closed position. The spring  13 , again a torsion spring, acts on the end of the hook element  16  facing away from the hook  12  and running out substantially straightly. 
     Within the scope of the invention, various structural modifications are, of course, feasible. Thus, the torsion spring  13  may be replaced with a plastic part preferably configured as a two-component injection-molding part to obtain the effect of an elastomer damper.