Abstract:
A safety binding for releasably holding the toe of a skier&#39;s boot to the top of a ski having a longitudinally extending median plane includes a base adapted to be attached to the top of the ski, and a clamping device mounted on the base for movement between a clamping position in which the toe of the boot is clamped to the ski and an unclamping position in which the toe of the boot is released from the ski. An actuator is provided for moving the clamp from its clamping position towards its unclamping position in response to up-and-down pivotal movement of the toe of the boot about an axis perpendicular to the median plane, or side-to-side pivotal movement of the toe of the boot about an axis perpendicular to the top of the ski. A spring-biased force transmission element is provided; and an interconnection between the force transmission element and the clamp is constructed and arranged to effect displacement of the force transmission element against the bias of the spring in response to either side-to-side pivotal movement of the toe of the boot or up-and-down movement of the toe of the boot, or combinations thereof.

Description:
This application is a continuation of application Ser. No. 242,891, filed Sept. 12, 1988 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a safety binding for a ski for releasably mounting the toe of a boot to a ski. 
     2. Description of Background and Relevant Information 
     Safety bindings for mounting the toe of a boot to a ski, known as &#34;front abutment bindings&#34;, comprise a body mounted on a base fixed to the ski. The rear portion of the body facing the toe of the boot generally carries a retention jaw in the form of two opposed lateral retention wings. An energization mechanism positioned in the body elastically biases the jaw into an engaged position in which the wings engage the toe of the boot and connect it to the ski. The elastic bias is created by a compressed energy spring, one end of which is supported on a support surface connected to the body, and the other end of which bears against a force transmission element that is longitudinally movable in the body. The force transmission element is coupled to the jaw in a manner so as to elastically bias the jaw to its engaged position at which the wings engage the toe of the boot and retain the boot on the ski. 
     Front abutment bindings of the type described above are disclosed in French Patent Nos. 2,179,183 (corresponding to U.S. Pat. No. 3,950,002) and 2,523,857; and also in German Patentschrifft 2,366,249. 
     The front abutment binding in French Patent No. 2,179,183 comprises a retention jaw constituted by two independent wings journaled on axes laterally displaced relative to the longitudinal median plane of the ski. The front or internal ends of these wings cooperate with an axial end of a member mounted for longitudinal sliding in the binding and biased by a spring which forms a portion of the energization mechanism. 
     French Patent No. 2,523,857 discloses a front abutment binding comprising a support pedal in contact with the sole of the boot and which constitutes a sensor for detecting a downward bias as the toe of the boot moves towards the ski in response to an incipient forward fall of the skier. The jaw in this binding is journaled around a horizontal and transverse axis effecting an upward pivotal movement of the jaw in response to an upward vertical force resulting from an incipient rearward fall of the skier. 
     The front abutment binding described in German Patentschrifft 2,366,249 is also the type having independent lateral retention wings journaled around respective axes. The sole grip on the binding is upwardly movable in response to an incipient rearward fall of the skier; and upward movement effects compression of a spring of the energization mechanism of the binding. Such compression lessens the stiffness of the binding and thus diminishes the force required for lateral release of the front binding. 
     It is an object of the present invention to provide a new improved safety binding that is more reliable than existing bindings, is simple in design, and has better sensitivity to release under the effect of a lateral bias imposed by the skier on the binding combined with either a frontward or rearward fall of the skier. 
     SUMMARY OF THE INVENTION 
     A safety binding according to the present invention for releasably holding the toe of a skier&#39;s boot to a ski having a longitudinally extending median plane includes a base adapted to be attached to the ski. A body is mounted on the base for upward pivotal movement away from the base about a first axis perpendicular to the longitudinal median plane. The body has movable retention means on its rear portion for engaging the front of a boot and maintaining the same on the ski when the retention means is in an engaged position, and for disengaging the front of the boot to release the same from the ski when the retention means is in a released position. An energization mechanism operatively associated with the body includes a force transmission element mounted for longitudinal movement on the base, and a spring engaged with said transmission element biases the transmission element. Linkage means are provided for linking the transmission element to the retention means so that the latter is resiliently biased towards its engaged position. 
     A first linkage element is pivotably mounted on the base for pivotal movement about a second axis perpendicular to the longitudinal median plane of the ski. Coupling means are provided on the first linkage element for coupling the same to the force transmission element. A second linkage element is pivotably mounted on the first linkage element for pivotable movement about a third axis perpendicular to the longitudinal median plane, and located between the coupling means and the second axis. Connection means are provided on the second linkage element for connecting the same to the rear portion of the body. Finally, the second and third axes, and the coupling means are constructed and arranged so that, upon upward pivotal movement of the body in response to an incipient rearward fall of the skier, the spring of the energization mechanism is further deflected to increase the bias on the transmission element. 
     The coupling means that couples the first linkage element to the force transmission element, the connection means that connects the second linkage elements to the body, and the linkage means that links the force transmission element to the jaw are constructed and arranged so that the binding is capable of releasing the toe of the boot from the ski in response to side-to-side pivotal movement of the toe beyond a threshold, and in response to up-and-down movement of the toe beyond a threshold, and combinations of these movements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Non-limiting embodiments of the present invention are shown in the attached drawings wherein: 
     FIG. 1 is a vertical, longitudinal cross-section of a front abutment binding according to the present invention showing the parts in their engaged positions, the binding including an energy cartridge attached to the base; 
     FIG. 2 is a horizontal cross-section taken along the line II--II of FIG. 1; 
     FIG. 3 is a partial perspective view of the upper portion of the front binding of the present invention showing a height adjustment screw separated from its receiving notch; 
     FIG. 4 is a vertical, longitudinal cross-section of the front abutment binding of FIG. 1, but showing the body of the binding pivoted upwardly under the effect of a vertical force due to an incipient rearward fall of a skier; 
     FIG. 5 is a horizontal partial cross-section of the piston of the energy cartridge and of the retention wings, the piston of the energy cartridge being shown displaced towards the rear resulting from a rearward fall of the skier; 
     FIG. 6 is a schematic elevation view, partially in section, illustrating the operation of a first linkage element of the front abutment binding of FIGS. 1-3 during an incipient frontward fall of the skier; 
     FIGS. 7 and 8 are longitudinal, vertical cross-sectional views showing the rest and the lateral biased positions respectively, of an embodiment of a front abutment binding according to the present invention in which linkage apparatus, interconnecting the first linkage element with the piston, is of the single-effect type; 
     FIGS. 9 and 10 are respectively longitudinal and vertical cross-sections showing the rest position and the lateral biased position, respectively, of an embodiment of a front abutment binding according to the present invention in which the energy cartridge is pivotally mounted with the body; 
     FIG. 11 is a vertical, longitudinal cross-section of an embodiment of the front abutment binding according to the present invention in which the energization mechanism comprises a forwardly biased longitudinal member; 
     FIG. 12 is a horizontal cross-section taken along line XII--XII of FIG. 11; 
     FIG. 13 is a vertical, longitudinal cross-section of an embodiment of the front abutment binding according to the present invention in which the energization mechanism comprises a rearwardly biased piston; and 
     FIG. 14 is a horizontal, partial cross-section of the front binding of FIG. 13. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to FIGS. 1 and 2, reference numeral 1 designates a front safety binding according to the present invention adapted to clamp the front or toe of ski boot 2 (shown in chain lines) to ski 3. Binding 1 comprises base 4 affixed to the ski and on which is mounted body 5 which can pivot with respect to base 4 around horizontal and transverse axle 6 positioned at the front of body 5. Axle 6 is perpendicular to the longitudinal median plane of the ski defined by axis xy as shown in FIG. 2. 
     Jaw 7, on the rear portion of body 5, is adapted to engage the upper edge of the sole of boot 2. This jaw is constituted by two lateral wings 8 which can be positioned to overlie the upper edge of the sole (FIG. 1) to assure retention of the boot against vertical displacement relative to the ski. 
     Each of lateral wings 8 is journaled on body 5 around vertical pin 11 and comprises rear branch 8a extending rearwardly of pin 11 to engage the upper edge of the sole when the wings are in operative position. Each of wings 8 further includes a short front branch having catch 8b extending substantially transversely to longitudinal axis xy of the front binding which defines a longitudinally extending median plane of the ski. 
     An energization mechanism for the binding is mounted in a longitudinal bore contained in housing 10 which is attached to base 4. The mechanism comprises longitudinally extending spring 12 supported at its front end on the transverse end of front cap 13 screwed into a threaded front portion of tubular extension 14 of piston 5 which is longitudinally slideable in the bore in housing 10. 
     Piston 15 includes lateral surfaces 15a which are transverse to axis xy and are respectively engagable by catches 8b of the retention wings 8 when the latter are in operative position. Clearance to permit catches 8b to engage surfaces 15a are provided by beveling the upper longitudinal edges of piston 15 to define relief portions in the form of longitudinally inclined surfaces 15b and 15c which slideably engage catches 8b when the piston moves longitudinally. Piston 15, threaded tubular extension 14 and cap 13, constitute a force transmission element. Internal energy spring 12, which is more or less compressed between pin 16 mounted in base 4 and cap 13 of the force transmission element, rearwardly biases the force transmission element. 
     The degree to which energy spring 12 is compressed, which is determined by the distance cap 13 is screwed into threaded tubular extension 14, determines the &#34;stiffness&#34; of the binding. The degree of stiffness is indicated by the relative axial position of cap 13 which can be observed through window 10a provided in upper wall 10b of housing 10 above the connection zone between cap 13 and extension 14. Energy spring 12 is supported at its rear on vertical pin 16 centered on axis xy and positioned at its lower end in hole 4a formed in the upper surface of base 4. Pin 16 extends vertically through longitudinal slots 15d and 15e in the upper and lower portions of piston 15. 
     The rear portion of piston 15 is coupled to a first linkage element constituted by bell crank or rocker 17 having lower branch 17a journaled on base 4 for pivotal movement around horizontal and transverse axle 18 whose axis is perpendicular to the longitudinal median plane of the ski. Rocker 17 also includes bifurcated upper branches 17b extending from branch 17a and inclined from bottom to top and from rear to front. The coupling means by which piston 15 is connected to rocker 17 in the embodiment shown in FIGS. 1-4 is a so-called double-effect type in the sense that displacement of piston 15, either forwardly or rearwardly, imparts pivotal movement to rocker 17. The coupling means comprises horizontal and transverse pin 19 carried by body 5 and vertically positioned, with respect to the top of the ski, above transverse axles 6 and 18. The free ends of pin 19 project through elongated inclined slots 21 in each of the upper portions of the branches 17b of rocker 17. Slots 21 are inclined from bottom to top, and from front to rear as seen in FIG. 1. 
     Rocker 17 further comprises rear activation extension 17c extending rearwardly from branch 17a. Extension 17c is horizontal, or slightly inclined from bottom to top and from front to rear in the rest or engaged position of the binding. On the free end of actuation extension 17c rests the free front end of pedal 20 journaled at its rear end for pivotal movement about horizontal and transverse axle 20a whose axis is perpendicular to the transverse median plane of the ski. When the boot is mounted on the binding, the sole of the boot engages pedal 20 which thus forms a frontward fall sensor. 
     Front binding 1 also includes a second rigid linkage element 22 which establishes a linkage between the first linkage element, constituted by rocker 17, and the upper rear portion 5a of body 5. Second rigid linkage element 22 is constituted by a second rocker or bell crank having vertical body 22a having branches 22b which extend from the lower end of body 22a, and which are inclined from top to bottom and from rear to front. Branches 22b are journaled respectively on bifurcated branches 17b of rocker 17 for pivotal movement around horizontal and transverse axle 23 whose axis is perpendicular to the longitudinal median plane of the ski. Relative to the top of the ski, axle 23 lies vertically below pin 19, and forwardly of axle 18. Axle 23 is located longitudinally on the binding between axles 6 and 18. That is to say, axle 23 is located between vertical planes that are perpendicular to the longitudinal median plane of the ski and respectively pass through axels 6 and 18. 
     The upper end of body 22a of second rocker 22 is threaded into vertical height adjustment screw 24 which comprises upper head 24a beneath which is annular grove 24b engaged in receiving notch 5b (FIG. 3) in an edge of upper and rear horizontal portion 5a of body 5. Notch 5b is located above rockers 17 and 22, and is defined by a U-shaped aperture that opens towards the rear. 
     When a purely lateral bias is applied to the binding, which results when the leg of a skier is twisted and the toe of the boot pivots on the ski about an axis perpendicular to the top surface of the ski, the rear branch of one of lateral retention wings 8 moves outwardly as the wing pivots around axle 11. Simultaneously, front catch 8b of the pivoting wing contacts transverse surface 15a of piston 15 and displaces the same rearwardly effecting rearward translation of the energy cartridge assembly. This displacement further compresses energy spring 12 until the boot reaches a predetermined angular displacement relative to the xy axis of the binding, termed the lateral release threshold, at which the sole of the boot near the toe thereof clears the rear branch of the wing that pivots, and the boot is freed from the binding. 
     In the case of an incipient purely rearward fall of the skier, wherein the boot pivots upwardly in the median plane of the ski about an axis perpendicular to the median plane, the toe of boot 2 raises jaw 7 which pivots body 5 in the clockwise direction around axle 6 as shown in FIG. 1. This movement of body 5 imparts an upward displacement to rocker 22 which is connected to body 5 through screw 24, and more particularly through groove 24b thereof engaged in notch 5b. This upward displacement of rocker 22 causes rocker 17 to pivot in the counter-clockwise direction as shown in FIG. 1 around axle 18 because of the upward movement of axle 23 by which rockers 17 and 22 are connected. The pivoting movement of rocker 17 imparts rearward displacement to piston 15 because of the coupling means between rocker 17 and the force transmission element established at pin 19 on piston 15 and slots 21 in rocker 17. Consequently, force transmission element 15, 14, 13 is moved rearwardly as shown in FIGS. 4 and 5. Energy spring 12 thus is further compressed until the jaw reaches a threshold at which the jaw is sufficiently open to free the boot from the binding. 
     In a case of a rearward fall of the skier combined with twisting of his leg, jaw 7 is upwardly biased at the same time that one of the wings is laterally displaced. As indicated above, the lifting of jaw 7 by the front of boot 2 effects retraction of piston 15 (FIG. 5) against spring 12, and front transverse surface 15a of piston 15 is displaced slightly from catches 8b of lateral retention wings 8. As a result, limited lateral displacement of the boot can be effected free from any bias imposed by spring 12 on such displacement. As a consequence, less lateral bias must be applied by the boot to effect its release from the front binding under these conditions than is required in the case of a purely lateral bias applied to the binding. In effect, a portion of the work absorbed by the additional compression of energy spring 12 is furnished by the lifting movement of front portion of the boot in response to a rearward fall. Consequently, the &#34;stiffness&#34; of the binding is lessened under these conditions. 
     In the case of a frontward fall, the boot of the skier exerts a downward vertical force Fl (FIG. 6) on pedal 20 directed towards the ski. The clockwise pivoting of pedal 20 as seen in FIG. 4 causes a counter-clockwise pivoting of rocker 17 around journal axis 18. The coupling means established by pin 19 and slots 21 in rocker 17 effects rearward displacement of piston 15 thereby compressing spring 12. This rearward movement of piston 15 is accompanied by the lifting of rocker 22 which results in an upward pivoting (i.e., clockwise as seen in the drawings) of body 5. As a result, jaw 7 opens and reduces its frictional engagement with the sole of boot 3. This movement likewise reduces the stiffness of the binding and has the advantage, if a torsional bias is associated with the forward fall, of reducing the lateral release threshold of the binding. 
     FIG. 6 illustrates, in a detailed manner, the role played by rocker 17 in the case of a forward fall. Rear 17c of rocker 17 is subjected to force F1 directed towards the top of the ski; and this translates into a force f acting on pin 19 near the upper end of branches 17b of rocker 17. Inclined slots 21 on arm 17 act against pin 19 imparting a rearward displacement to piston 15. The magnitude of force f reduces the stiffness of the binding, depending on the moment arms a and d of leg 17c, and the angle A between the leg and arm 17b. Judicious selection of the values of moment arms and the angle permit the stiffness of the binding to be designed to accommodate different levels of skill of a skier. 
     As can be seen in FIGS. 1-4, leg 22a of rocker 22 preferably has an upper shoulder 22c which contacts rear fixed portion 10c of upper wall 10b of housing 10 in a manner so as to limit upward pivotable movement of body 5 about axle 6. 
     In the embodiment shown in FIGS. 7 and 8, the coupling means between piston 15 and rocker 17 is of the single-effect type, which is to say that rearward movement of the piston may occur independently of any pivotal movement of rocker 17. Thus, this embodiment differs from the embodiment previously described which utilizes a double-effect type of coupling means. In the embodiment of FIGS. 7 and 8, each branch 17b&#39; of rocker 17 is in the form of an arm which extends upwardly and is inclined from bottom to top and from rear to front. The upper free end portion of this arm simply rests against horizontal and transverse pin 19 fixed to piston 15 at a point beneath, and forwardly, of this pin. As a result, in the case of a purely lateral bias on the binding, i.e., a side-to-side pivotal movement of the toe of the boot about an axis perpendicular to the top of the ski such as is produced by a twisting of the skier&#39;s leg unaccompanied by a rearward fall of the skier, the pivotal movement of one of the retention wings 8 causes catch 8b to engage and rearwardly displace piston 5 against the bias of spring 12 as in the preceding embodiment. In this particular embodiment, however, such rearward displacement of the piston is unaccompanied by simultaneous pivotal movement of rocker 17 which remains stationary. As a result, both rocker 22 and body 5 are unaffected by the retraction of the piston. 
     On the other hand, when rocker 17 is involved in the release process, e.g., in response to pivotal movement of the toe of the boot about an axis perpendicular to the median plane of the ski occasioned by an incipient forward or rearward fall of the skier, rocker 17 pivots counterclockwise as seen in FIG. 7 about axel 18 causing the arms on branch 17b; to push against pin 19 thereby rearwardly displacing piston 15. In this case, body 5 pivots about axel 6, but the &#34;stiffness&#34; of the binding is reduced as compared to the &#34;stiffness&#34; of the binding in response to combined side-to-side pivotal movement of the toe of the boot and upper displacement of the body due to twisting of the leg of the skier during a forward fall. 
     In all of the embodiments of the invention described above, screw 24 makes it possible to adjust the height of jaw 7 to accommodate various thicknesses of sole 2 of the boot. The vertical position of groove 24b in screw 24, and consequently the angular position of body 5 in relation to base 4, is dependent on the degree to which screw 24 is threaded into body 22a of rocker 22. This adjustment in no way affects the bias exerted by spring 12 of the energization mechanism. 
     In the embodiment of the invention shown in FIGS. 1-8, the energization mechanism is in the form of energy cartridge 12-15 which remains connected to base 4 while being contained in housing 10. Only body 5 pivots in this embodiment. However, an energy cartridge that pivots together with body 5 can be provided. Such an alternative embodiment is shown in FIGS. 9 and 10. In this embodiment, housing 10&#39; enclosing the energy cartridge, which is constituted by spring 12, cap 13, tubular extension 14 and piston 15, is part of pivotal body 5&#39; which also supports pin 16 whose lower end is fixed in lower wall 10d&#39; and which projects into a longitudinal opening in the housing. In this alternative embodiment, body 5&#39; pivots about pin 6 which is carried by a pair of extension arms projecting forwardly and upwardly adjacent the front end of the base. 
     In the embodiment of the invention shown in FIGS. 11 and 12, the housing containing the force transmission element of the energization mechanism is rigidly attached to the base as with the embodiment of FIGS. 1-4; but the force transmission element includes longitudinally extending stay rod 25 coaxially supported in longitudinal bore 26 in housing 10&#34; by a central hub in transverse wall 28. The front end of compression spring 12, which surrounds rod 25, is supported on cap 27 slideably mounted in bore 26, and which is threaded to the front of rod 25. The degree of compression of spring 12, and consequently the &#34;stiffness&#34; of the binding, is adjustable by screwing cap 27 inwardly or outwardly on rod 25. The rear end of compression spring 12 is supported in a bore contained in the central hub on wall 28 which slideably supports rod 25 for forward and rearward longitudinal movement. The rear end of rod 25 is fixed to head 29 which has a width sufficient for front surface 29a of the head to engage catches 8b of lateral retention wings 8 (FIG. 12). These catches are received in the space between front surface 29a of head 29 and transverse wall 28. 
     As shown in FIG. 12, catch 8b of wing 8 is engaged with the front surface of head 29 which is coupled to the upper portion of the first linkage element constituted by rocker 17 by means of pin 19 engaged in slots 21 of branches 27b of the rocker. Alternatively, this double-effect coupling means can be modified so as to utilize a single-effect coupling means as previously described with respect to FIGS. 7 and 8. 
     In the embodiment of the invention shown in FIGS. 13 and 14, body 5&#34; is pivotably mounted on the base in a manner similar to that shown in FIG. 9, and contains force transmission element 31 constituted by a piston slideably positioned in longitudinal bore 32 of body 5&#34;. Element 31 is biased towards front 33 of bore 32 by compression spring 12 which is supported, at its front end, on stiffness adjustment cap 34 threaded into a tapped hole provided at the front end of bore 32. Horizontal and transverse pin 19 in element 31 is engaged in inclined slots 21 in the upper end portions of branches 17b of rocker 17. In this embodiment, the slots are inclined from bottom to top and from front to rear. Consequently, in this embodiment of the invention, the lower journal axle 18 of rocker arm 17 (i.e., the third axis in the system) is longitudinally located between vertical planes that are perpendicular to the median plane and that contain, respectively, journal axles 19 of branches 17b and journal axle 36 of rocker 5&#34;. In this case, each lateral retention wing 35 of jaw 7 is journaled on body 5&#34; for pivotal movement about vertical axis 11 in a manner so as to displace piston 31 forwardly (i.e., to the right as seen in FIGS. 13 and 14) when a lateral bias is applied to wing 35. To this end, each wing has a transverse front surface 35a in contact with transverse projection 31a of piston 31. In this manner, projection 31a and consequently piston 31, are displaced forwardly when wing 35 is itself pivoted outwardly relative to the ski in response to side-to-side movement of the toe of the boot. 
     The front abutment shown in FIGS. 13 and 14 likewise comprises pusher 37 mounted under the rear portion of body 5&#34; for slideable longitudinal movement on the base. Pusher 37 comprises horizontal arm 37a extending towards the rear and terminating in rear surface 37b forming a cam inclined from bottom to top and from front to rear. Surface 37b supports the front end of pedal 20 which forms a forward fall censor. Pusher 37 comprises, on its front portion, vertical branch 37c which extends upwardly and which engages in a clearance opening in the lower portion of piston 31. The upper portion of the front surface of branch 37c engages rear vertical surface 31b of piston 31. 
     In the case of a forward fall, the free end of pedal censor 20 is displaced by the sole of the boot toward the top of the ski and slides on inclined cam 37b which forwardly displaces pusher 37 on the base. Vertical branch 37c of pusher 37 engaged with piston 31 imparts forward movement to the pusher which results in additional compression of energy spring 12 thus reducing the &#34;stiffness&#34; of the binding in response to a lateral bias produced by side-to-side movement of the toe of the boot. The forward displacement of piston 31 likewise imparts upward vertical displacement to journal axle 19 as body 5&#34; pivots in the clockwise direction as seen in FIG. 13. This upward movement of body 5&#34; slightly opens jaw 7 and consequently reduces the friction exerted by the jaw on the top edge of the sole of the boot as the latter moves relative to the binding. 
     Although, in all the embodiments of the invention previously described, the binding has been assumed to include independent lateral retention wings journalled around respective axes, it is evident that the double rocker mechanism likewise can be applied to a front binding utilizing a monoblock jaw, i.e., a jaw in which two lateral retention wings form a single element with a central linkage portion constituting a sole grip. 
     Finally, although the invention has been described with reference to particular means, materials and embodiments, it is to be understood that the invention is not limited to the particulars disclosed and extends to all equivalents within the scope of the appended claims.