as shown , the ski binding comprises a hollow flat sole plate 1 of generally uniform thickness along its entire length , able to be fitted under the sole 2 of a boot by front and rear grips 3 and 4 respectively . the rear end 18 of plate 1 is held on ski 10 by flexible and substantially inextensible ski connector leash or strand or cable 19 . for this purpose , as shown , an enlarged end 20 of cable 19 is secured in a heel engagement plate 22 screwed on ski 10 ; after leaving plate 22 , cable 19 passes over a pulley 23 freely turning on a pin 24 fixed in an opening in the rear end of plate 1 , and the cable then passes along a groove 26 , for example of spiral shape as shown , in a cam - like winder 25 and its other enlarged end 27 is held in one of several housings in winder 25 . the front end 5 of plate 1 as shown , is similarly held on ski 10 by a second flexible ski connector leash or cable 6 . an enlarged end 7 of cable 6 is secured to a turning toe engagement element 8 pivoted on a pin 9 fixed to the ski by a plate 12 screwed on ski 10 . from this element 8 , cable 6 passes over a pulley 13 freely turning about a pin 14 fixed in an opening in plate 1 ; then it passes along a groove , for example of spiral shape , at the periphery of a cam - like winder 15 and its second enlarged end 11 is held in one of several openings , not shown , in the winder 15 , in the same manner as for winder 25 . the winders 15 and 25 are each pivoted on a rotatable shaft 29 carrying a rim 30 which is keyed for rotation with the shaft . to this rim 30 is secured the inner end 32 of a spiral spring 31 , 33 respectively . the outer end 54 of each spring is hooked to a drum 55 integral with the respective winder 15 , 25 . a pusher 34 ( fig2 ) able to lodge in one of several notches 35 of a toothed wheel 37 fixed on shaft 29 , serves to angularly fix the shaft 29 and thus hold the tension of the spring at a value set by rotation of rim 30 by means of an allen key engaging in a polygonal opening 38 in the accessible upper end of shaft 29 . a cover 41 is placed on plate 1 , over winders 15 and 25 . the traction on toe engagement element 8 , exerted in rearward direction 39 by front cable 6 under the action of spring 31 , tends to hold a profiled part 42 of the front end of plate 1 with forward pressure against a part 40 of complementary profile on turning element 8 . two rollers 43 , pivoted on the front end of plate 1 about longitudinal axes , bear on ski 10 and allow rolling of plate 1 on ski 10 in transverse directions 44 and 45 . fig1 shows a lower portion of one roller 43 . the traction on heel engagement plate 22 , exerted in forward direction 46 by rear cable 19 under the action of spring 33 , becomes substantially perpendicular to the surface of ski 10 as rear cable 19 passes over pulley 23 thus tending to hold rollers 48 ( which are pivoted on plate 1 about a transverse horizontal axis ) down against parts 47 of this plate 22 . these parts 47 and rollers 48 are of complementary profile arranged so that the plate 1 always tends to be centered on ski 10 when it is held against plate 22 . these parts 47 are also sufficiently long to allow rolling of rollers 48 and hence a given axial movement of plate 1 in direction 39 or 46 . when there is a slight force on sole 2 transverse to the ski , for example in direction 44 , plate 1 pivots slightly in direction 44 by rolling of its rollers 43 , but it remains held on ski 10 by the profile 40 of element 8 which engages the complementary profile 42 of plate 1 . if the force ceases , plate 1 is moved back to its normal centered position by spring 31 , winder 15 and cable 6 . if , however , the force exceeds a certain predetermined value , profile 42 disengages from profile 40 , element 8 pivoting as indicated at 49 , and the plate 1 is able to move away from ski 10 . at the moment when profile 42 disengages from profile 40 , plate 1 moves back slightly in direction 39 by rolling on its rear rollers 48 . as soon as the force on sole 2 ceases , the traction exerted by spring 31 of winder 15 brings the ski 10 back against rollers 43 , and the binding thus once more returns to its normal &# 34 ; skiing &# 34 ; position . in the event where , upon a forward fall of the skier , a force tends to lift the rear of sole 2 as indicated at 51 , the plate 1 tends by winder and cable mechanism 25 , 19 ; to lift ski 10 in the same direction 51 . if this force exceeds a given preset value , the plate 1 lifts up so that rollers 48 leave their supporting part 47 of plate 22 , and the boot is thus freed from the ski at the same time as plate 1 . as soon as the force on sole 2 ceases , the traction exerted by spring 33 of winder 25 brings the ski 10 back under rollers 48 , and the binding once more automatically assumes its normal &# 34 ; skiing &# 34 ; position . the elastic biasing means for each cable could be other than a spiral spring . in a simplified embodiment , the cable could be secured to a spring , e . g ., a tension spring . also , the front and rear cables could have elastic biasing means of different types . also , instead of the end 20 of cable 19 being secured to the ski it could be secured to plate 1 and for example be attached to the ski by passing around a pulley fixed on the ski . it is of course understood that the terms leash , cable and flexible connection as used herein are meant to include all suitable flexible strands , cords , wires and other substantially non - extensible flexible elongate members .
a safety ski binding has a hollow hole plate of uniform thickness removably fixable under a boot sole . the ends of the sole plate are each retained on a ski by a respective flexible cable held under tension by respective spiral - spring winders both housed within the sole plate .