Abstract:
A release ski binding having a sole plate which in its center area can be pivoted about an approximately vertical axis and can be tilted up about a transverse axis arranged in front of the vertical axis, which sole plate is held on the ski in the skiing position by a resilient holding mechanism, which holding mechanism is responsive to a swivelling movement of the sole plate relative to the ski and, upon reaching a predetermined angle of traverse, effects both an upwardly and also a side opening of a locking mechanism which secures the shoe on the sole plate, and which locking mechanism consists of at least one heel holder pivotal about a transversely extending axis.

Description:
FIELD OF THE INVENTION 
     This invention relates to a ski binding which engages the middle part of a ski boot and, more particularly, to a ski binding incorporating therein a sole plate movable elastically of the ski until a release condition is exceeded. 
     BACKGROUND OF THE INVENTION 
     Such release ski bindings are described in German Pat. No. 2 533 337. In these conventional ski bindings the spring of the holding mechanism acts through a piston onto an approximately mushroom-shaped follower member, which is supported pivotally to all sides in the housing of the holding mechanism. The stem portion of the mushroom-shaped follower member is received in a recess of a ski-fixed fitting. In these known ski bindings, the ski shoe is held at its tip or toe by means of a rigid bar on the sole plate. In the case of a fall of the skier to the rear, the ski shoe is therefore released only with great difficulty. 
     This disadvantage is avoided in the ski binding according to German Pat. No. 2 324 078, however, this binding is complicated in its design. That is, the release mechanism is housed in the space between the base plate and the sole plate. This, however, requires special seal structure to prevent the penetration of snow and dirt therein. Furthermore, the installation is complicated and expensive. 
     The goal of the invention is to overcome the disadvantages of the conventional designs and to provide a release ski binding of the above-mentioned type, which is simple in its design and in which the ski shoe is reliably held during skiing, however, is immediately released in the case of a fall. 
     This goal is inventively attained primarily by providing a locking mechanism having two clamping jaws which engage laterally the ski shoe and which are constructed as two-arm levers, which clamping jaws are pivotal on the sole plate about axes which extend in the longitudinal direction of the ski and by the transverse axis of the heel holder being movable in the longitudinal direction of the ski and being under the influence of a pressure spring which urges it toward the tip of the ski. 
     The concept supporting one-arm clamping jaws, which laterally engage the ski shoe, on a sole plate and to move them through a slide plate with the help of wedge-shaped shoulders into the clamping position is actually already known through the teachings in German OS Nos. 2 943 209 and 3 026 918. However, in these constructions the locking spring acts directly onto the clamping jaws, the load of which is utilized for the automatic release of the ski binding, and which brings about certain inexactnesses compared with the ski bindings of the above-mentioned type in which the angle of traverse of the sole plate is decisive for effecting the opening of the locking mechanism. 
     Of course, various solutions exist to swing the clamping jaws into the clamping position. However, it has been proven to be particularly preferable if the two clamping jaws are movable into the clamping position by means of clamping wedges movably supported on the sole plate and are under the influence of springs, in particular a pressure or compression spring. In this manner, it is possible to bring about with relatively small spring forces a strong urging of the upper arms of the clamping jaws on the ski shoe. 
     Furthermore, the invention provides that the two clamping wedges are hingedly connected by a crossbar to a pull rod which extends in a direction toward the tail end of the ski, which pull rod is loaded by the pressure spring in a direction toward the tip end of the ski. This measure contributes to the release of the two wedges occurring evenly. 
     Furthermore, according to a different characteristic of the invention, the crossbar is connected through a pin, received in a slotted hole in the pull rod, to said pull rod. It is made possible through this measure that the pull rod, which not only handles the opening of the two clamping jaws, but also, as will be discussed below, unlocks the heel holder, carries out these two operations in specified timely intervals one after the other. 
     According to a further development of the invention, the transverse axis for the heel holder is supported on a piston guided in a hole in the sole plate extending in the longitudinal direction of the sole plate, and a second piston is also movably supported in said hole, which second piston is connected through a transverse bolt to the fork-shaped constructed end of the pull rod. The pressure spring is arranged between both pistons. Furthermore, the second piston has a piston rod secured thereto and which projects from the hole into operative engagement with an operating member of the holding mechanism. The pressure spring is, through this development, not only utilized for urging the heel holder onto the ski shoe during skiing, but at the same time for releasing the two clamping jaws, for example in the case of a fall. 
     In order to hold the heel holder reliably in the skiing position, various locking mechanisms can be used. However, it has been proven as being particularly preferable to provide at least one hook-shaped locking member hingedly connected to the heel holder, which locking member is under the influence of a torsion spring and in the skiing position of the ski binding grips with its hook under a projection of the sole plate. It is thereby preferable if a stop on the pull rod is associated with the locking member. The stop permits a release of the heel holder prior to the two clamping jaws having opened, so that first the heel and then the toe-piece of the ski shoe is released. 
     According to a further characteristic of the invention, the heel holder is under the influence of a helical erecting spring supported at one end on a transverse axis supported on the sole plate and at the other end on a transverse axis on the heel holder. This type of support for the erecting spring permits the heel holder to always be under the pressure of the erecting spring, regardless of whether the heel holder is in the position (stepping-in position) which is caused by the pressure spring and which is moved forwardly toward the tip of the ski or in the moved-back position (skiing position) which is caused by a stepping down by the ski shoe. 
     Finally, the invention provides that the heel holder is guided in a vertical guide slot in the housing on the sole plate. This causes the axis for the heel holder to be substantially protected, since independent from whether the ski shoe is inserted into the ski binding parallel with respect to the vertical longitudinal center plane of the ski or inclined with respect to same, a force is applied onto the axis, which force is always only normal with respect to the axis. Furthermore, a bending of the heel holder during a rough stress or loading of the ski binding is also resisted. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An exemplary embodiment of an inventive ski binding is illustrated in the drawings, in which: 
     FIG. 1 is a side view of the ski binding in the skiing position, partly in cross section taken along the line I--I of FIG. 2; 
     FIG. 2 is a partially sectioned top view of the ski binding; 
     FIG. 3 is a longitudinal central cross-sectional view of a detail of the ski binding; and 
     FIG. 4 is a sectional view taken along the line IV--IV in FIG. 3 but wherein the ski binding is laterally deflected. 
    
    
     DETAILED DESCRIPTION 
     Three holding elements are secured to the upper surface of a ski 1, namely a transverse axle 1a, a substantially vertical axle 1b and a bearing block 1c. A sole plate 2 is provided above the ski. The sole plate 2 can be pivoted in the vertical direction about the axis of the transverse axle 1a and can be rotated about the axis of the vertical axle 1b approximately in a parallel plane with respect to the upper surface of the ski. Two clamping jaws 3 are pivotally supported on axes 3a located on the side surfaces of the sole plate 2. The clamping jaws 3 are constructed as two-arm levers and are under the influence of weak torsion springs which are not illustrated and which urge the clamping jaws into engagement with the ski shoe. One such construction is disclosed in a copending application Ser. No. 572 099 entitled RELEASE SKI BINDING, filed concurrently herewith. 
     The region of the sole plate 2 closest to the tail end of the ski defines a housing 2a, on which is secured a holding mechanism 4 and in which is provided an axially extending hole 2b. Two axially spaced pistons 5 and 6 are movably supported in the hole 2b. A pressure spring 7 is arranged between the two pistons 5, 6. The piston 5 which is closest to the tip of the ski carries a bearing clock 5a thereon on which is pivotally supported a fork-shaped constructed heel holder 8 movable about an axis 8b. The heel holder 8 is under the influence of an erecting spring 8a and is guided in a vertically oriented guide slot 2e in the housing 2a. The end of the heel holder 8 has a recessed construction which engages, in the skiing position, the heel of the ski shoe. The heel holder 8 together with the two toe clamping jaws 3 hold the ski shoe during skiing reliably on the ski 1. Furthermore, at least one hook-shaped locking member 9 is hingedly mounted on the heel holder 8, which locking member 9 is under the action of a torsion spring 9a and grips, in the skiing position, with its hook under a projection 2c of the sole plate 2. 
     The sole plate 2 has in the region of the two toe clamping jaws 3 two approximately trapezoidally shaped recesses 2d, in which clamping wedges 10 are supported. The clamping wedges 10 are under the influence of pressure springs 10a. The clamping wedges 10 each have upstanding pins 10b on their upper side, which pins are received in slotted holes 11a of a crossbar member 11. The crossbar member 11 has also an upstanding pin 11b in its center, which pin is received in the slotted hole 12a of a pull rod 12. The pull rod 12 extends to the housing 2a on the sole plate 2 and becomes bifurcated at its end which is remote from the clamping jaws 3. The ends of the two legs or prongs of the pull rod 12 are hingedly connected to the piston 6 by means of a pin 13. Of course the pin 13 is guided on both sides of the piston 6 in guide slots in the housing 2a. Furthermore, the pull rod 12 has at least one stop 12b thereon designated or adapted to effect a release of the locking member 9. A piston rod 6a is attached to the piston 6 and can, for example, be constructed as a bearing for a roller 14 (FIG. 3) to serve as a support for an operating member 15 of the holding mechanism 4. 
     The operating member 15 in the holding mechanism 4, which is illustrated in FIGS. 3 and 4, is constructed as a toggle lever supported for pivotal movement about an axle 15a and which is loaded or biased for movement in the counterclockwise direction by a torsion spring 16. One arm 15c of the toggle lever engages the roller 14 and is held in this position by a stop 15b. The other, fork-shaped constructed arm 15d of the toggle lever 15 engages a transversely extending pin 17 which extends through a pair of laterally aligned slotted holes 4a in the holding mechanism 4. A piston 19 which is loaded by a pressure spring 18 is guided in a longitudinal hole 4b of the holding mechanism 4 and projects between the legs 15d of the toggle lever to engage the pin 17. The initial tension of the pressure spring 18 can be adjusted by means of an adjusting screw 20. 
     Furthermore, a generally mushroom-shaped follower member 21 having an enlarged head 21a is pivotally supported in the hole 4b of the holding mechanism 4. The stem portion 21b of the follower member has two spherical enlargements 21c and 21d spaced along the length thereof. The stem portion 21b extends through an outwardly diverging conical hole in the bottom wall of the hole 4b in the holding mechanism 4. The bearing block 1c for the follower member 21, which bearing block is secured to the ski 1, has two guideways thereon, namely a horizontal guideway 22a and a vertical guideway 22b, of which the guideway 22a is associated with the spherical enlargement 21c and the other one 22b with the spherical enlargement 21d. 
     In the stepping-in position of the ski binding, the heel holder 8 is under the influence of the erecting spring 8a in the erected position. The piston 5 is moved under the influence of the pressure spring 7 toward the tip of the ski in the hole 2b. The clamping jaws 3 are held in vertical position by the wedges 10 acting through the pressure springs 10a. The ski shoe is now, with a slightly lowered tip, first moved between the clamping jaws 3, and thereafter the heel of the ski shoe is stepped down upon. The heel holder 8 is thereby swung counterclockwise and at the same time the pivot 8b therefor is moved slightly toward the tail end of the ski. The heel holder 8 and shoe sole form a kind of a toggle joint during the stepping down event. However, by moving the pivot axle 8b of the sole holder 8 rearwardly, the pressure spring 7 is tensioned or compressed. The ski shoe is therefore urged forwardly between the toe clamping jaws 3 by the pressure spring 7 acting on the heel holder 8. The heel holder 8 is locked with respect to the sole plate 2 in the lower end position by the locking member 9. 
     If during skiing, the sole plate 2 is swung in the vertical and/or horizontal plane, then also the follower member 21 is swung, which results in a movement of the piston 19 in a direction toward the tail end of the ski. If thereby the so-called elastic region of the ski binding is exceeded in the horizontal or in the vertical direction, then the toggle lever 15 is swung clockwise by the piston 19 to cause the end of the lever arm engaging the roller 14 to become disengaged from the roller. The pressure spring 7 which is housed in the hole 2b now becomes relaxed because the piston 6 will be driven rearwardly by the spring force from the spring 7. This has the result, that the clamping wedges 10 are pulled back by the pull rod 12, and that also the heel holder 8 is relieved from the pressure of the pressure spring 7, which tries to move it toward the ski shoe. Through the rearward movement of the pull rod 12, the locking member 9 was also unlocked by the stop 12b effecting a disengagement thereof from the projection 2c  on the sole plate 2. The heel holder 8 can therefore swing upwardly clockwise under the influence of the erecting spring 8a to facilitate the release of the ski shoe. 
     The voluntary release of the ski binding occurs by means of a release lever which is supported in the holding mechanism 4, however, is not illustrated in the drawings. Through this lever the arm 15c of the toggle lever 15 is removed from engagement with the roller 14 against the force of the torsion spring 16. The remaining operation corresponds with one occurring during the automatic release of the ski binding. 
     As soon as the ski shoe has left the ski binding, the pull rod 12 returns with the piston 6 under the influence of the pressure springs 10a, which load the clamping wedges 10 to move them into the position which is illustrated in FIG. 2, and in which the arm 15c of the toggle lever 15, under the influence of the torsion spring 16, rests on the roller 14. The heel holder 8 remains in the swung-up position after the ski shoe has left the binding. The ski binding is therefore ready for the ski shoe to again step thereinto. 
     Of course the invention is by no means to be limited to the exemplary embodiment which is illustrated in the drawing and which is described above. Rather, various modifications of the same are possible without leaving the scope of the invention. For example, it is possible to use in place of a cross-bar and a pull rod a slide plate hingedly connected to the piston, which piston is adjacent to the tail end of the ski and received in the recess in the sole plate.