Ski binding
The present invention relates to a binding designed to hold a boot, more particularly the heel thereof, to a support such as a ski, or to a plate fitted to a ski. 
     The invention relates, more particularly, to a binding comprising a jaw arranged to pivot, upon a mounting, about a first axis secured thereto, and a lever for removing the boot arranged to pivot about a second axis secured to the mounting, the lever and jaw cooperating by means of a ramp-and-stop system and being urged into contact with each other by means of a resilient element which makes it possible to keep the jaw in the position in which it holds the boot to the ski. 
     Devices of this kind are already known, for instance from published German Patent Applications Nos. 1,728,514 and 2,125,357 and from German Utility Models Nos. 7,023,403 and 7,127,472. The devices described in these references are heel-pieces which permit: 
     Voluntary unlocking of the binding by actuation of the boot-releasing lever which compresses a spring acting between the jaw and the lever, the pivoting movement of the lever releasing the jaw and making it possible for the skier to raise the boot without any effort; 
     Automatic refitting of the binding, or &#34;step-in&#34;, after the jaw has been opened, this refitting being made possible by the presence of a pedal associated with the jaw. 
     These known bindings, however, have certain disadvantages. For instance: on the one hand, they are quite bulky, due to the need for locating the axes of pivot at a distance from the jaw and the lever, which runs the risk of causing the spring to buckle, as may be seen particularly well in German Patent Application No. 2,125,357; on the other hand, their design restricts the displacement of the pivoting parts and thus restricts the resilient travel of the jaw. This restriction of the angular displacement of the pivoting parts is one of the disadvantages which the above application No. 1,728,514 seeks to overcome by increasing the complexity of the binding. It is essential that a binding be able to function satisfactorily, even if the ski boots have soles of different thicknesses, or if there is snow between the boot and the support, which amounts to the same thing as a difference in sole thickness. 
     If the resilient travel of the jaw is unable to allow for such conditions, the binding will not operate properly and there may be a danger of the skier falling. 
     It is the purpose of the present invention to provide a device of the type mentioned hereinbefore, which will overcome the disadvantages of known bindings. 
     The binding according to the invention takes up little room on the ski, allows the resilient element to operate under satisfactory mechanical conditions, and allows sufficient resilient travel of the jaw to absorb variations in thickness of the soles of normal boots. 
     To this end, the binding according to the invention comprises: 
     A mounting secured to the support; 
     A jaw arranged to pivot about a first axis on the mounting in a manner such that it can move between a position in which the boot is held to the support and a position in which the boot is released; 
     a boot-removing lever arranged to pivot about a second axis on the mounting, the lever and jaw cooperating by means of a ramp-and-stop system; 
     a resilient element urging the ramp and stop into contact with each other, the binding being characterized in that the resilient element is attached to the jaw and to the lever in such a manner that it applies a pull to the jaw and lever between its points of attachment. 
     The point at which the resilient element is attached to the jaw is located on the same side as the ramp-and-stop system, in relation to the point of attachment of the resilient element to the lever. 
     The resilient element is preferably located opposite the ski when considering the pivot axes of the jaw and the lever on the mounting, in such a manner that the axes are as close as possible to the ski and are adjacent to each other. This reduces the size of the binding. 
     The size of the binding is also reduced by the advantage of arranging the pivot axes of the jaw and the lever so that they are substantially one above the other, the mounting thus extending vertically from the ski by a small amount. 
     In order to allow the resilient element to operate under suitable mechanical working conditions, the element is free to orient itself angularly at the points of attachment to the jaw and lever. The action of the resilient element will thus always be along the line joining the points of attachment. 
     According to one preferred example of embodiment of the invention, the ramp is arranged in the jaw, whereas the stop, which may be in the form of a rotating roller, is carried by the lever. 
     The resilient element may be in the form of any suitable resilient system exerting traction between these two points of attachment. However, according to a first example of embodiment, it may, with advantage, consist of a strip of rubber, one end of which is secured to the jaw and the other to the lever. According to another example of embodiment, the resilient element is in the form of a telescoping piston-and-hollow member unit hinged at one end to the jaw and, at the other end, to the lever, a spring operating under compression being arranged between the piston and hollow member. 
    
    
     A description will now be given, as a non-restrictive example, of two examples of embodiment of the heel-piece according to the invention illustrated in the drawings attached hereto, wherein: 
     FIG. 1 shows a section through a first example of embodiment of the invention; 
     FIGS. 2, 3 and 4 are diagrams showing how the heel-piece according to FIG. 1 operates; 
     FIG. 5 shows a section through a second example of embodiment of the invention; and 
     FIG. 6 shows the heel-piece according to FIG. 5 in another position. 
    
    
     In the example of embodiment illustrated in FIGS. 1 to 4, the heel-piece is designed not to allow safety releases. In other words, this is a binding in which the locking action, once established, cannot be reversed. The boot can therefore be released only intentionally by the skier. 
     It will therefore be assumed that the device according to FIGS. 1 to 4 is designed to hold a boot to a plate fitted, for example, to a ski, safety releases between the plate and the ski being achieved by means of a releasable holding device. 
     In FIG. 1, item 1 is a ski to which is fitted a plate 2 which is held to the ski by front and rear safety-release bindings 3&#39; and 3. This type of binding is conventional and is not a part of the invention; it will therefore not be described in detail. 
     Shown at 4, in dotted lines, is the rear of a ski boot. The front of this boot is to be held firmly to plate 2 by means of a conventional stop (not shown), while the rear of the boot is held by the heel-piece according to the invention. 
     Although the heel-piece as shown is not intended to release itself but to lock the boot irreversibly, it may be open and closed by the skier intentionally for the purpose of securing the boot to, and releasing it from, the ski. 
     The binding comprises a stationary pedestal 5 which, in the example illustrated, is substantially U-shaped and has a web 6 which is secured to the plate. 
     The two arms of the pedestal have axes O 1  and O 2  which run parallel with the ski and are arranged in a manner such that the line O 1  O 2  is at an angle α of about 35°, for example, to the ski in the example illustrated. A jaw 9, designed to hold boot 4 against plate 2, pivots about axis O 1 . Jaw 9 has a step-in pedal 12 pivoting about an axis 13. 
     The jaw extends rearwardly in the form of two parallel cheeks 14 through which axis O 1  passes. The central portion of cheeks 14 is in the form of a ramp 15 which projects inwardly and is extended rearwardly in the form of a recess 16. A boot-removing lever 17 is arranged to pivot about axis O 2  between cheeks 14, the lever extending upwardly from axis O 2  and carrying, on each side, stops 19 which are cylindrical in the example illustrated. These stops 19 are integral with lever 17 and are intended to cooperate with ramps 15 of the holding element. 
     The upper end of lever 17 has a cavity 20 designed to accept the end of a ski stick used to move the lever in the direction of arrow D when the skier intentionally removes the boot from the ski. 
     Angle β indicates the opening travel of the jaw. C 1  and C 2  are the extreme positions that can be reached by top 11 of the sole of the boot without preventing the heel-piece from being locked, the distance between C 1  and C 2  corresponding substantially to the amount of snow which can be tolerated under the boot without disturbing the functioning of the binding. 
     The binding is also equipped with a spring which, in the example illustrated, is in the form of a strip of rubber 21 capable of stretching, one end thereof being secured to lever 17 around an axis 22, while the other end is secured to jaw 9 by being pinched between wall 23 of the jaw and a pin 24 integral therewith. This strip of rubber exerts traction between axis 22 and pin 24, tending to maintain lever 17 in the position shown in FIG. 1. 
     FIGS. 2 and 3 are diagrams illustrating the locking of the heel-piece according to FIG. 1: (a) in the case of a standard boot with no snow under the sole, and (b) in the case of a boot having snow under the sole (FIG. 3). 
     As for FIG. 4, this shows, diagrammatically, the device in the open position, after manual removal of the boot, with stop 19 engaged in recess 16 in the jaw. 
     The presence of spring 21 provides automatic opening and closing of the device at the end of the travel. Thus, in fitting the ski, when the boot bears upon the pedal, it causes the jaw to move a certain distance, lever 17, under the action of spring 21, pivots towards the jaw, and stop 19 emerges from recess 16 and moves along ramp 15 of the jaw. Spring 21 is then unloaded and the jaw and the lever move simultaneously, although their angular movements are relative. 
     At the end of a certain amount of travel, the lever makes use of the energy of the spring in order to close the jaw. 
     When the ski is removed, the procedure is reversed, i.e. after the lever has travelled a certain distance under spring tension, it becomes the driver and carries along the jaw. The latter opens under the action of the spring and remains open in the position shown in FIG. 4. 
     On the other hand, when the boot applies a vertically upward load to the jaw, the latter cannot pass from the &#34;closed&#34; position to the &#34;open&#34; position releasing the boot, since the angle of ramp 15 is such that there is not enough force to rotate the lever carrying roller 19 in a clockwise direction. 
     The heel-piece illustrated in FIGS. 5 and 6 allows safety releases. It consists of a baseplate 30 secured to a ski 31, the base-plate comprising a mounting consisting of two wings 32 arranged at an angle to the ski; the mounting has a first axis O 1  about which a jaw 33 pivots, and a second axis O 2  about which a boot-removing lever 34 pivots. 
     In the example of embodiment illustrated in FIGS. 5 and 6, axis O 1  is located above axis O 2 , but it is to be understood that this arrangement could be reversed without altering the operation of the heel-piece. 
     Lateral cheeks 35 of the jaw comprise a ramp 36 terminating in a heel 37, the ramp being designed to cooperate with a roller 38 running freely on an axis 39 carried by lever 34. 
     The sides of lever 34 contains slots 40 accommodating stationary axis O 1 , the slots allowing lever 34 to move in relation to jaw 33. 
     Located between jaw 33 and lever 34 is a telescoping resilient element marked 41 as a whole, the element consisting of a hollow elongated member 42, the base of which is hinged, at 43, to the upper part of jaw 33; the piston of the telescoping resilient element is in the form of a threaded rod 44, head 45 of which has a hemispherical surface 46 bearing upon a spherical seat 47 on lever 34. Threaded end 48 of the rod carries a plate 49 which slides in member 42. Located between plate 49 of the piston and bottom 50 of member 42, and surrounding rod 44, is a spring 51 working in compression. It will be understood that, in this arrangement, the action of the spring tends to move axis 43 towards head 45 of rod 44. 
     When a load in the direction of arrow G (FIG.5) is applied to jaw 33, the latter tends to pivot about axis O 1 , and ramp 36 imparts to lever 34, through roller 38, a rocking movement. Roller 38 rolls upon ramp 36, and the relative movement between the jaw and lever compresses spring 51. 
     As soon as roller 38 reaches nose B located between ramp 36 and heel 37 thereof, a safety release occurs, whereupon the unit assumes the position illustrated in FIG. 6. It will be observed that the position illustrated in FIG. 6 is stable, in that roller 38 bears against heel 37 and this prevents any unwanted closing of the binding. 
     In order to fit the boot to the ski, the skier merely has to apply pressure to pedal P, integral with the jaw. This causes the latter to descend, and lever 34 returns to its upright position under the action of telescoping resilient element 41. 
     In order to remove the boot intentionally, the skier applies pressure, in the direction of arrow F, to the top of lever 34. This enables the lever to pivot freely against the action of spring 51, and roller 38 follows a path T which releases ramp 36 and therefore jaw 33. It is obvious that, in this example of embodiment, ramp 36 is arranged differently and at an angle other than that of ramp 15 in FIGS. 1 to 4.