Abstract:
The assembly consists of a boot whose sole ( 42 ) is fitted with a transverse bar ( 38 ) which engages between a bearing piece ( 11 ) and a self-locking cam ( 29 ). The bearing piece ( 11 ) is secured to a sliding piece ( 10 ) and the cam ( 29 ) is mounted on a piece ( 19 ) which preferably slides. These two pieces are mounted in a rail ( 2, 3 ) while being drawn toward one another by springs ( 16 ). The bar ( 38 ) can be disengaged by means of a lever ( 32 ). This binding releases both in the event of falling forward or backward and in response to twisting.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a boot/ski binding assembly which can release in the event of falling both forward or backward and in response to twisting, consisting of a boot whose sole is fitted with a transverse bar and of a binding which has a longitudinal direction and a transverse direction and comprises means for retaining the boot by its bar. 
     U.S. Pat. No. 4,182,524, the content of which is incorporated by reference, discloses a boot/binding assembly in which the boot is fitted with two bars projecting on each side of the boot so as to form two pairs of studs used to secure the boot to a plate of the binding, this plate being itself mounted on a central block on which it is retained elastically in rotation by two rectangular frames bearing on two opposite flats of the central block. In this assembly, the means for releasing, on the one hand, when falling forward or backward and, on the other, in response to twisting, are separate from one another and are each controlled by their own elastic disengagement device. This binding is relatively complicated, and the studs form inappropriate projections on each side of the boot. Also, removing the boot from the binding requires compression of the release springs retaining the boot on the plate, and hence considerable effort. 
     Further, Patent Application EP 0 408 824, the content of which is incorporated by reference, discloses a boot/binding assembly in which the boot is fitted with two substantially vertical plates articulated about two axes parallel to the longitudinal direction of the boot, these plates interacting with retaining rollers that can be moved apart from one another when the boot is being fitted in the binding and in the event of falling forward or backward. These retaining rollers are mounted on a plate which is itself mounted on a central block about which the plate can pivot in the event of twisting forces, against the action of two springs. In this case as well, the means for releasing when falling forward or backward and in response to twisting are separate means controlled by their own spring an associated mechanism. In order to remove the boot intentionally, it is necessary to move apart the plates mounted on the boot, so that the means for actuating these plates are also located on the boot, which encumbers and complicates the boot. 
     U.S. Pat. No. 4,177,584, the content of which is incorporated by reference, presents a boot fitted with two transverse bars extending laterally beyond the sole on each side of the boot so as to form two pairs of studs intended to be retained by two pairs of arms of a ski binding. This binding is not described in this document, but it can be seen from the drawings that release in response to twisting is not possible. 
     Further, International Patent Application WO 97/22390, the content of which is incorporated by reference, discloses a snowboard binding consisting of a stirrup provided with two notches in which the transverse bar fitted to the boot engages by moving apart a pair of cams automatically wedging the bar in the notches. This binding does not, however, have any means of releasing the boot in the event of falling, and it is hence not a safety binding. 
     The safety bindings mentioned above are also susceptible to the build-up of snow which can easily prevent the boot from being fitted in the binding. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a boot/ski binding assembly which is simpler than the assemblies known from the prior art, is less susceptible to the build-up of snow in the binding and requires less effort for removing the boot from the binding. 
     The boot/ski binding assembly according to the invention is one wherein the boot-retaining means located on the binding consist, on the one hand, of a transverse recess which has a notch-shaped profile and is formed between two pieces, at least one of which can be moved longitudinally against the action of at least one spring, and, on the other, of a self-locking cam articulated about an axis transverse to the binding on one of the pieces and urged to rotate by a spring tending to keep it engaged in the recess, the shape of the surface of the cam intended to come into contact with the bar being such that the bar, once engaged in the recess after having moved the cam away, tends to move the cam with it by friction when an upward force is exerted on the bar, so that the bar stays locked in the recess by wedging between the cam and the retaining piece which is not supporting the cam. 
     The boot is fitted with a single bar which does not extend laterally beyond the sole and works in its central region. In the event of falling, the effect of the force exerted on the bar is to push back the moving piece or pieces by bearing on the cam, both in the case when the bar experiences a force directed upward and when it experiences a twisting force. A single, relatively simple, system hence makes it possible to control release when falling forward or backward and release in response to twisting. 
     Given that the cam works as an element for taking up play and allows the bar to be wedged at any height over a certain range, the boot/binding assembly according to the invention is substantially unsusceptible to the build-up of snow in and on the binding. It is always possible to fit the boot in the binding quickly. 
     The boot can be fitted in the binding without effort, because this does not involve compressing the release spring or springs. When the boot is being fitted in the binding, the bar simply needs to move the cam away, optionally against the action of a weak return spring whose resistance is not in any event felt by the user. 
     Similarly, the boot is removed from the binding by acting on the cam, that is to say by pivoting it in the opposite direction to its locking direction. In this case as well, it is not necessary to compress the release spring. 
     According to a preferred embodiment of the invention, the two pieces of the retaining means can be moved longitudinally against the action of at least one common spring working in compression between two parts respectively secured to each of the two pieces. 
     The means for releasing the boot advantageously consist of a lever and a connecting element, such as a tie bent at its end, for rotating the cam in the opposite direction to its locking direction. This lever may be articulated to the front or rear of the binding for it to be actuated by hand or using a ski pole. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The appended drawing represents two embodiments of the invention by way of example. 
     FIG. 1 is a plan view of the binding and of the bar of the boot fixed to the binding, but without the boot, according to a first embodiment. 
     FIG. 2 is a view in section on II—II of FIG. 1 in which the profile of the sole is represented. 
     FIG. 3 is a view in section on III—III of FIG.  1 . 
     FIG. 4 is a plan view of the moving elements of the binding, but without the retaining pieces, in which the bar of the boot is also represented in order to locate the position of these moving elements. 
     FIG. 5 is a perspective view of a second embodiment of the binding. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the first embodiment, the body of the binding consists of a plate  1  having a thickness of about 2 cm, but in any event sufficient to make it possible for two recesses  2  and  3  of rectangular parallelepipedal shape, extending longitudinally one after the other over the majority of the length of the plate  1  and separated by a cut-out wall  4 , to be formed in it. A thin plate  5 , having a rectangular cut-out  6  whose width is slightly less than the width of the recesses  2  and  3 , is fixed on the plate  1  so as to form a rail with a T-shaped profile. Such a rail could, of course, have been machined in the plate  1 , but in this case it would have had to have opened at least at one of the ends of the plate  1 . The plate  1  is provided with four holes  7  for fastening it to a ski. 
     The plate  1  also has, at one of its ends, a cylindrical axial hole  8  opening into the part  2  of the rail (FIG.  2 ). 
     Two sliding pieces of rectangular shape  9  and  10  are mounted in the part  2  of the rail. The piece  10  consists of a first retaining piece fitted with a jaw  11  rising above the plate  1 . The piece  10  is set back in its horizontal part so as to form a hollow  12  in which a piston  13 , having two parallel cylindrical indentations such as the indentation  14  (FIG.  3 ), is mounted so as to slide, which indentations respectively accommodate two identical parallel springs  15  and  16  working in compression between the bottom of the hollow of the piece  12  and the piston  13 . The piece  9  has a threaded axial hole  17  whose axis lies in the vertical plane of symmetry of the plate  1 . This hole  17  engages on a screw  18  which is accessible through the hole  8  in the plate and bears on the piston  13 . 
     A second piece  19 , also sliding in the rail and of rectangular shape, from which a pair of parallel supports  20  and  21  facing the jaw  11  rise, is mounted in the other part  3  of the rail. The piece  19  also has two threaded holes parallel to the axis of the rail, such as the hole  22  (FIG.  3 ). The threaded ends of two rods  23  and  24 , provided with a head  25  by which these rods bear on the piece  9 , are respectively screwed into these holes. 
     It can be seen that the sliding piece  9 , which tends to be pushed back by the piston  13  under the thrust of the springs  15  and  16 , is actually retained by the rods  23  and  24 , which are themselves retained by the sliding piece  19  butting against the intermediate wall  4  of the rail. For the same reason, the sliding piece  10  is held bearing against the other side of th is wall  4 . 
     Between them, the jaw  11  and the supports  20  and  21  define a transverse recess  26  having a notch-shaped profile (FIGS. 2 and 3) widening in its upper part. On the side next to the jaw  11 , this profile has an oblique side  27  inclined in the direction of the supports  20  and  21 , while the opposite side  28  of the notch is rounded. A heart-shaped cam  29 , suspended in its upper part about a transverse pin  30  carried by the supports  20  and  2   1 , is mounted between the supports  20  and  21 . When the notch  26  is free, the cam  29  occupies, under the effect of its own weight and optionally an auxiliary spring, the position  29 ′ represented by dots and dashes, that is to say it penetrates into the notch  26 . The cam  29  penetrates into the notch  26  by a cylindrical convex face  31 . 
     The plate  1  is also provided at one of its ends with a lever  32  which is articulated, about a pin  33  transverse to the plate, in a notch  34  of the plate. A tie  36  whose bent end  37  is located, at rest, slightly in front of the cam  29 , at the border of the notch  26 , is attached to this lever  32  at a point  35 . In this position, the lever  32  is held butting against the top of the plate  1  by a spring (not shown), for example a torsion spring mounted about the pin  33 . 
     This binding is intended to hold a boot whose sole  42  is fitted with a cylindrical transverse metal bar  38  in a central hollow  39  of the sole by means of a metal stirrup. The diameter of the bar  38  is such that the lower part of the profile of the recess  26  has a width substantially equal to the diameter of the bar  38 . This width is substantially constant in the lower part of the notch  26  and increases in the upper part. 
     Before the boot is fitted in the binding, the cam  29  occupies the position  29 ′. When the boot is being fitted in the binding, the bar  38  encounters the cam  29  and pushes it away without effort. The cam  29  then returns to bear against the bar  38 , as shown. In this position, a wrenching force directed upward exerted on the bar  38  tends to move the cam  29  with it by friction and consequently reduce the width of the notch  26  owing to the eccentricity of the working face  31  of the cam. The bar  38  is consequently retained in the notch  26 . The slope at the point of contact between the cam  29  and the bar  38  is great enough to lock the cam, but nevertheless not strong enough for this locking to prevent the cam  29  from being moved away from the bar  38  with ease by the tie  36  by means of an action on the lever  32 , as indicated by the arrow, FIG.  2 . This boot-removal action takes place without stressing the springs  15  and  16 . 
     In the event of falling, that is to say a force on the bar  38  exceeding a certain value, the bar moves the jaw  11  and the cam  29  apart from one another by compressing the springs  15  and  16 , and disengages from the notch  26 . This can occur both owing to pulling forces lying in a plane passing through the axis of the bar and owing to a torque tending to rotate the bar in a horizontal plane. Since the system is in principle balanced, the two sliding pieces  10  and  19  are both moved away from the rib  4  and the piece  19  moves the piece  9  along with it. 
     The precompression of the springs  15  and  16 , that is to say the hardness upon release of the binding, can be adjusted by means of the screw  18 . The setting is displayed by an index  40  which, in the example represented, consists of a notch in the piston  13 , this notch being visible through a slot  41  in the piece  10 . 
     According to an alternative embodiment, the pieces  9  and  19  could be fixed to the plate  1 , only the jaw  11  being mobile in this case. 
     As represented, the boot-release lever  32  is located to the rear of the plate, that is to say behind the heel of the boot. Nevertheless, all this could be reversed of course, with the boot-release lever lying in front of the plate, and the position of the jaw  11  and of the cam  29  being altered accordingly. 
     The second embodiment, represented in FIG. 5, can be regarded as a variant of the first embodiment. In this case, the transverse recess consists of two notches  50  and  51  formed by the bent lateral parts  52 ,  53  and  54 ,  55  of two plates  56  and  57  equivalent to the pieces  10  and  19  of the first embodiment. Two cams  58  and  59 , similar to the cam  29  of the first embodiment, are mounted on the bent parts  52  and  53 . The cams are articulated about an axis a and are connected to one another by a link  60  crossing the bent parts  52  and  53  through holes located at the bottom of the bent parts  52  and  53 . This link  60  is also used as the rotation pin of a boot-release lever  61  acted on by a torsion spring tending to hold the boot-release lever in the lowered position as represented. On the side next to the bent part  53 , the link  60  is bent two times and its end is engaged in a slit  62  of the cam  59 . The spring of the boot-release lever  61  hence tends to hold the cam  59  lowered, as represented. The other cam  58  has a slit similar to the slit  62 , and a finger which is secured to the lever  61  and fulfils the same role as the bent end of the link  60 , is engaged in this slit. The cams are thus mechanically connected. 
     In order to remove the boot from the binding, the lever  61  is lifted, the effect of which is to pivot the cams downward and open the notches  50  and  51 , releasing the bar  38  which, in this case, is retained at two locations close to its ends. 
     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.