Front jaw for safety ski bindings
The invention relates to a front jaw for a safety ski binding, comprising two levers which are pivotable about vertical shafts on a jaw portion that is fixed with respect to the ski and which in their normal position are influenced by a spring to engage a central abutment. 
     In known such jaws, the levers each carry a sole holder which can swivel freely about a vertical shaft. The sole holders are in the form of angular levers and are automatically adjustable within wide limits to the width of the sole when the boot is introduced in the ski binding. 
     Since a certain amount of standardisation of sole widths is taking place to an increasing extent in the case of ski boots, the expense involved in catering for boots having widely different sole widths is often no longer necessary. 
     The purpose of the present invention is therefore to construct a front jaw of the aforementioned kind so that, without the expense of known front jaws, it offers adequate adjustability for adapting to different sole widths of modern ski boots whilst meeting all the other conditions required for the safety function of such a front jaw. It is also important that use can be made easily of the possibility of adjustment, even when the boot is located in the binding. 
     According to the invention, a front jaw for a safety ski binding comprises two levers which are pivotable about vertical shafts on a jaw portion that is fixed with rspect to the ski and which in their normal position are influenced by a spring to engage a central abutment, wherein the free ends of the levers serve as retainers for the sole of a ski boot to restrain outward and upward movement thereof, the abutment is formed by a spacer member having a tapped hole engaging a screw which is rotatably mounted in the jaw but prevented from axial displacement, and an oblique plane is provided between the spacer member and each of the levers. 
     By turning the screw, the spacer member can be moved upwardly and downwardly so that the sole holders become more or less spread apart on account of the wedge action of the oblique planes and a wider or narrower mouth is defined for receiving the front end of the sole. The spacer member is prevented from turning together with the screw by reason of the resilient abutment of the sole holders against the spacer member. 
    
    
     Other features of the invention will become evident from the following description of an example illustrated in the accompanying drawing, wherein: 
     FIG. 1 is a plan view of the front jaw in which the right-hand half of the jaw is shown cut open, and 
     FIG. 2 is an elevation of the FIG. 1 jaw viewed from the sole holder end. 
    
    
     The illustrated front comprises a jaw portion 3 which is secured on a ski 1 by two screws 2 and which consist of a U-shaped bent piece of sheet metal. Two vertical shafts 4, 5 are provided in the two limbs of the jaw portion and each of these supports a pivotable lever 6 or 7. The outer free end of each lever serves as a holder 8 for the sole of a ski boot (not shown) to prevent outward and upward movement thereof. 
     A helical compression spring 10 is supported on the web 9 of the jaw portion 3. By way of a pin 11 passing through the web of the jaw portion and by way of a yoke 12, this spring acts on the inner free ends of the two-armed levers 6, 7 so that the latter are in their normal position held in abutment against a spacer member 13. This spacer member is provided with a tapped hole engaged by a screw 14. The screw 14 is parallel to the shafts 4, 5 and is rotatable in the jaw portion 3 but held against axial displacement. The faces 15, 16 of the levers abutting against the spacer member diverge downwardly (see FIG. 2). 
     By turning the screw 14, the spacer member 13 can be moved upwardly and downwardly so that the ends of the levers 6, 7 forming the sole holders 8 are spread more or less apart on account of the wedge effect of the oblique planes and define a wider or narrower mouth for receiving the front end of the sole of a ski boot. 
     In the position illustrated in FIG. 2, the spacer member 13 is in its upper limiting position. The sole holders 8 are spread apart by a maximum amount. If, now, a ski boot is introduced in the binding, the correct position of the sole holders can be readily set by appropriately screwing the spacing member further downwardly. 
     As will be evident from the left-hand half of FIG. 1, the jaw portion 3 carries a cap 17 covering the spring. To facilitate assembly of the front jaw, each sole holder contains an assembly hole for the respective mounting screw 2, as will be evident from FIG. 1. 
     The spacer member is a simple nut of which the abutment faces for the sole holders are mirror-image symmetrical. 
     In contrast with the illustrated construction, it is of course also possible for the faces of the sole holders that make contact with the spacer member to diverge upwardly. Further, the oblique planes could be provided on the spacer member itself, in which case the latter will have the shape of the frustum of a pyramid.