Abstract:
A ski binding includes a stop ( 3 ) and a heel piece ( 5 ). An elastic means opposes the release of the stop and the heel piece. The elastic means includes a blade ( 6 ) working in buckling mode between two slides ( 2, 4 ) which correspond to the stop and the heel piece, respectively. Conventional springs for releasing the stop and the heel piece are therefore replaced by this longitudinally arranged blade.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a ski binding intended for disengageably attaching a boot to a ski, comprising a front binding, known as a stop, and a rear binding, known as a heel piece, this stop and this heel piece being held elastically in a determined position corresponding to the position of the boot attached to the ski, and in which position the front stop is held elastically by a spring arranged at least approximately longitudinally in the direction of the heel piece. 
     A binding of this kind is known from U.S. Pat. No. 5,735,541, the content of which is incorporated by reference. The longitudinally-mounted spring is a helical spring which opposes the pivoting of the jaw of the stop. The heel piece comprises an attachment body in which is mounted approximately vertically a spring which opposes the pivoting of a heel-gripping jaw which acts on the spring via a piston. The stop and the heel piece are connected by a bar which acts as a support for the heel piece, but they could be mounted on the ski independently of one another. Therefore, as far as the stop is concerned, this binding differs from previous ski bindings in which the release spring is mounted in the body of the stop. Moreover, this binding comprises, like the earlier bindings, a helical spring made of steel for each of the binding elements, front and rear. What is more, in the heel piece, the spring still occupies a significant volume of the body of the heel piece. 
     In document U.S. Pat. No. 5,899,484, the content of which is incorporated by reference, it has, incidentally, been proposed that, in one stop, the helical spring should be replaced by a blade working in buckling mode. A solution of this kind has the advantage that in buckling, the resistance offered by the blade drops sharply, allowing the boot to escape more easily, the buckled blade behaving like a spring of relatively low stiffness but with a high preload. 
     SUMMARY OF THE INVENTION 
     The present invention aims to produce a ski binding with a simpler stop, and heel piece, a small volume and allowing greater use of elements made of non-metallic composite. 
     To this end, the ski binding according to the invention is one wherein said spring, arranged at least approximately longitudinally, consists of at least one blade operating in buckling mode and also elastically retaining the stop. 
     This blade is arranged flat under the boot, in a space which becomes available by the raising of the boot, which is characteristic of the current tendency in favor of edge gripping. It is preferably made of a composite material such as fiber-reinforced plastic, the fibers being made of glass or of carbon or of KEVLAR (trade mark), but it could just as easily be made of metal. 
     The stop and the heel piece no longer have a spring. Forces can be applied from the jaws of the stop and of the heel piece to said blade simply using levers or cams. 
     The simplest construction consists in making the blade work in buckling mode between two parts that can move in longitudinal translation and are kinematically connected to the stop and to the heel piece, respectively. 
     The kinematic connections may be achieved using levers. 
     According to one embodiment of the invention, the stop and the heel piece are mounted on a longitudinal support in the form of a slide, in which there are mounted two sliders associated respectively with the stop and with the heel piece so as to be carried along toward one another when the stop or the heel piece is displaced relative to its position of rest, said blade being mounted between these two sliders. 
     With the exception of the levers which provide the kinematic connection between, on the one hand, the stop and the heel piece and, on the other hand, the sliders, the stop and the heel piece may be made in the known way and it is even possible to re-use the existing stop and heel piece elements in their current form. As far as the heel piece is concerned, the piston found in many heel pieces is advantageously kept as an intermediate element between the jaw and the lever, for applying the force of the jaw to the lever, this piston advantageously being guided in a direction that encourages forces to be transmitted from the jaw to its slider. 
     The setting of the binding may be adjusted simply by using a part surrounding the blade and mounted like a nut on a longitudinal adjusting screw mounted and retained axially in one of the sliders. 
     It should be remembered that in order to adjust the length of the binding, that is to say to alter it to suit the size of the boot, it is necessary for it to be possible to move the heel piece relative to its slider, and this means that it must be possible for the point connecting the heel piece to its slider to move. To adjust the length, the heel piece will generally be in such a position that the blade has moved beyond its buckling point and it is necessary to keep the blade in that condition during adjustment. This can be done simply using an auxiliary screw stop screwed longitudinally into said longitudinal support. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawing depicts, by way of example, one embodiment of the binding according to the invention. 
     FIG. 1 is a view in vertical axial section of the binding, with the heel piece in the engaged position. 
     FIG. 2 is a plan view, from above, of the binding, without the heel piece body and the elements articulated to this body and, at the front, the arms of the front stop, one is which is depicted in section. 
     FIG. 3 is a side view showing details of the rear of the binding. 
     FIG. 4 is a detail view of the front part of the binding, with the blade compressed. 
     FIG. 5 is a sectioned view similar to FIG. 1, depicting the heel piece in the open position. 
     FIG. 6 is a sectioned view similar to FIG. 1, showing the heel piece in a position for adjusting to suit the boot size. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference is first of all made to FIGS. 1 and 2. The binding depicted essentially comprises a longitudinal support  1  in the form of a slide in which there is mounted a first slider  2  associated with a stop  3  constituting a front binding element, and a second slider  4  associated with a heel piece  5  constituting a rear binding element, and a blade  6  arranged horizontally in the support  1  between the sliders  2  and  4 . 
     Further referring to FIG. 3, the longitudinal support  1  is attached to the ski at the front by means of an intermediate attachment piece  7  on which the support  1  is articulated about a transverse axle  8  and, at the rear, by means of an intermediate part  9  secured to the ski by screws like the part  7  and in which the support  1  is held vertically by a transverse axle  10  but can slide longitudinally in two opposed grooves or slots  11 . This way of mounting the binding on the ski has the effect of making the ski unbound in the region of the binding. The ski can therefore flex freely in this region. 
     The stop  3  is a stop similar to the stop described in U.S. Pat. No. 4,889,359, the content of which is incorporated by reference. It does, however, differ from that stop in that it has a shortened stop body  12  which no longer contains either a spring or a tubular nut against which the spring rests. What it does retain, on the other hand, is the tie rod  13 , one end of which is connected to the arms  14  and  15  of the stop via a vertical axle  16 . The other end of the tie rod  13  is, in this instance, connected to a lever of the second kind  17 , the lower end of which is articulated to the support  1  about a transverse axle  18 . As depicted in FIG. 2 of U.S. Pat. No. 4,889,359, the arms  14  and  15  press on vertical ribs of the binding body  12 , on which ribs they can rock, exerting tension on the tie bolt  13 . The lever  17  presses at an intermediate point against a nose  19  of the slider  2  (FIG. 4) which, in FIG. 1, is hidden by an axial adjusting screw  20  used to adjust the release setting of the binding, as will be described later on. This screw  20  is borne by the slider  2  through which it passes through an unthreaded part. It is held axially in the slider  2  by a collar  21 . Its threaded part is engaged in a part  22  through which the blade  6  passes freely. Using the screw  20 , it is thus possible to move the part  22  along the blade  6 . 
     The heel piece  5  also re-uses the elements of a heel piece of the known type, except for its spring. One recognizable element is a jaw or sole-gripper  23 , formed as one piece with a lever  24  for deliberately opening the binding and articulated to a binding body  25  about a transverse axle  26 . Another recognizable element is the interior ramp  27  of the jaw  23 , against which there bears the nose  28  of a piston  29  sliding in an axial cylindrical housing  30  in which there is no longer the spring customarily found in heel pieces of this type. Articulated to the nose  28  of the piston  29 , about a transverse axle  31 , is the upper end of a lever  32  made of a U-shaped part passing over the nose  28  and extending roughly vertically on each side of the piston  29 . This lever  32  constitutes the retaining element of the sole-gripper jaw  23 . It has a transverse intermediate axle  33  to which is articulated one end of a first arm  34 , the other end of which is held in first serrations  35  consisting of two opposed sets of teeth, belonging to the support  1 . As the arm  34  is rigid, the axle  33  constitutes a fixed articulation of the lever  32  relative to the support  1 . The lower end of the lever  32  has a transverse axle  36  about which is articulated one end of a second arm  37 , the other end of which is fixed in serrations  38 , consisting of two opposed sets of teeth, belonging to the second slider  4 . The rotation of the lever  32  about the axle  33  therefore has the effect of moving the slider  4  in the support  1 . This movement is visible in FIG. 5 where the heel piece  5  is depicted in the open position. In this position, the jaw  23  has pushed back the piston  29  which has driven the lever  32  which has forced the slider  4  to move forward. The slider  2  is held by the lever  17 , itself held by the tie rod  13  rigidly retained by the arms  14  and  15  of the front stop  3 . The axial compression of the blade  6  is such that this blade buckles as can be seen in FIG.  5 . 
     As can be seen in FIG. 2, the teeth of the serrations  35  and  38  are precisely superposed so that, when viewed from above, just one of these sets of serrations is visible. The opposite ends of the arms  34  and  37 , from their joints to the lever  32 , are connected by a transverse axle  39  integral with the arm  34  and passing through a horizontal longitudinal aperture  40  in the arm  37 . Those parts of these arms which are adjacent to this articulation  39  have, on each side, teeth which correspond to the teeth of the sets of teeth  35  and  38  and which are engaged with these teeth. The end  41  of the upper arm  34  is elbowed twice and can be reached using a tool, for example a screwdriver, th rough a hole  42  in the binding body  25 . 
     The binding also comprises a screw stop  43  mounted on by a vertical rear wall  44  of the support  1 . This screw stop is used when adjusting the length of the binding, that is to say when adapting the binding to suit theboot size. This adjustment is depicted in FIG.  6 . With the heel piece  5  open and the blade  6  therefore deformed in buckling, the screw  43  is screwed in until it comes into abutment against the slider  4 . Using a tool  45 , the arm  34  is raised via its elbowed end  41  so as to disengage the teeth of this arm from the teeth  35  of the support  1 . As the arms  34  and  37  are connected by the articulation  39 , the teeth of the arm  37  are also disengaged from the teeth  38  of the slider  4 . The compression of the blade  6  is maintained by the screw stop  43 . The heel piece  5  can therefore be moved along the support  1 . A spring  46  causes the teeth of the arms  34  and  37  to re-engage in the respective sets of teeth  35  and  38 . Once the re-engagement has occurred, the screw  43  can then be unscrewed to return it to the position depicted in FIG. 5, that is to say a position in which the blade  6  can return to a straight unbuckled position as depicted in FIG.  1 . 
     FIG. 1 depicts the binding without a boot. When a boot is secured in the binding, the arms  14  and  15  of the front stop  3  will be parted slightly by the thrust of the sole of the boot. The tie rod  13  will therefore be in tension so that the lever  17  is pressed firmly against the end of the slider  2 . As the slider  4  is rigidly held, the blade  6  is subjected to a certain amount of axial compression, this compression not, however, being enough to cause this blade to buckle. 
     When a great deal of stress is exerted, either in terms of torsion on one of the arms  14  or  15  of the stop  3 , or upward on the jaw  23  of the heel piece  5 , the axial compression of the blade  6  increases until this compression becomes great enough (the Euler force) to cause the blade to buckle, this buckling allowing the slides  2  and  4  to move closer together and therefore allowing the parting of the stressed arm  14  or  15  or the lifting of the jaw  23 , allowing the boot to come free of the binding. During buckling, the resistance offered by the blade drops sharply, encouraging the boot to come free. 
     The binding setting is adjusted by altering the length of that part of the blade  6  which is able to buckle. This adjustment is achieved by moving the part  22  (FIG. 4) using the screw  20 . It can be seen in this figure that the length of the blade  6  liable to buckle is between the moving part  22  and the slider  4 . The more this length is shortened, the tighter the binding will be. The length of that part of the blade which is between the part  22  and the slider  2  is of course always markedly shorter than the length of the part lying between the part  22  and the slider  4 . 
     The screw  20  could of course be mounted in the slider  4 , but for space and convenience reasons it has been mounted in the slider  2 . 
     The blade  6  is preferably made of composite material, for example glass-fiber reinforced plastic or carbon-fiber reinforced plastic. 
     In place of a single blade, it would be possible to use several blades, particularly stacked blades or blades placed side by side. 
     Although illustrative embodiments of the invention have been shown and described, a wide range of modification, change and substitution is contemplated in the foregoing disclosure and in some instances, some features of the present invention may be employed without a corresponding use of the other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.