Patent Publication Number: US-7210698-B2

Title: Ski binding

Description:
RELATED APPLICATIONS 
   This application is a continuation-in-part of U.S. patent application Ser. No. 10/229,152 filed Aug. 27, 2002 now U.S. Pat. No. 6,877,759. 

   BACKGROUND OF THE INVENTION 
   The present invention relates in general to ski bindings, and pertains, more particularly, to ski bindings that are preferably used with a Telemark ski. 
   One traditional Telemark ski binding employs a front latch for securing the boot in the binding. This is typically referred to as a three pin 75 mm Nordic Norm binding. These types of bindings have traditionally required the skier to bend down and manually press down upon a latch mechanism at the front of the toe of the ski boot to attach the ski boot to the binding. This is a rather cumbersome arrangement, and it is time consuming in engaging the ski boot with the binding. 
   Another traditional Telemark binding employs a heel cable to secure the boot to the binding. This also is a cumbersome arrangement requiring time consuming positioning and adjustment for proper securing of the ski boot to the binding. Also, the cable may affect the overall flexibility and use of the ski by the skier. 
   It is an object of the present invention to provide an improved ski binding, preferably for use with a Telemark ski and in which the binding is a step-in binding. 
   Another object of the present invention is to provide a ski binding that is of the step-in type and that comprises a toe piece that readily accepts and engages the ski boot and provides means for simple and ready disengagement. 
   Still another object of the present invention is to provide a ski binding with an integral ski brake that deploys to arrest the forward movement of the ski when a skier steps out of the binding, particularly a binding for telemark skiing. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention there is provided a step-in binding for receiving a ski boot, comprising: a base constructed and arranged to be secured to the ski; and a pair of boot support members pivotally supported from a front side of the base, and disposed laterally on either side of the base. The pair of boot support members is biased to a boot receiving or open position and further has a locked or closed position that is assumed once the boot is received, engages the pair of boot support members, and is cantilevered downwardly into the locked position. A release lever is arranged at the front of the base, readily accessible to the skier and includes a member that releases the pair of boot support members from the locked position to the boot receiving or boot released position upon activation of the release lever. 
   In accordance with other features of the present invention there are the following aspects. The boot is interlocked from both top and bottom. A base has a pressure plate on a front top surface that firmly engages an underside of the boot. The pressure plate is slightly elevated above the rest of the top surface of the base and includes securing pins engageable in holes in the boot for retaining the boot in place. A ridge may also be associated with the pins or substituted for the pins. A cross bar is disposed between the pair of boot support members for engaging the front top of the boot and a pair of stop posts are associated respectively with the pair of support members. The member that releases the pair of support members includes a latch pin that extends through the base retained at its front end at the release lever and has a back end that engages and locks the pair of support members. A cross piece preferably extends between the lateral support members for engagement with the back end of the latch pin, the latch pin being tapered at its back end so as to displace when the lateral support members move downwardly yet lock with the cross piece when fully engaged. A spring is for biasing the latch pin toward a backward position, the base having a front to back passage for receiving the latch pin. The base comprises an outer metal shell and an inner plastic core that has the passage therein. The release lever may be supported from the base by means of a pivot pin, the release lever held by the pivot pin and supported at the front end of the latch pin. Preferably a ski brake is integrated into the base and has wings that extend through the pair of lateral support members. At least one spring is disposed in the base for biasing the brake and for urging the later support members away from the locked position. 
   In accordance with another aspect of the present invention there is provided a step-in binding for receiving a ski boot preferably for telemark skiing, comprising: a center block constructed and arranged to be secured to the ski; and a pair of boot support members pivotally supported from a front side of the base, and disposed laterally on either side of the base. The lateral side members are preferably tapered inwardly toward the front so as to receive and guide the ski boot as it is to be engaged. The pair of boot support members is biased to a boot receiving position and further has a locked position that is assumed once the boot is received, engages the pair of boot support members, and is cantilevered downwardly into the locked position. A cross bar is disposed transversely between the pair of boot support members for engaging the front top of the boot over the duckbill. A release lever is arranged at the front of the base, readily accessible to the skier and including a member that releases the pair of boot support members from the locked position to the boot receiving position upon activation of the release lever. A ski brake may be integrated into the base, releasable should the boot become disengaged, and constructed and arranged to urge the lateral support members from the locked position to the released position. The center of the cross bar receives the front of the toe box, and the ends of the cross bar extend rearwardly preferably by a distance of 0.75 inches and in a range on the order of 0.25 to 1.75 inches. 
   In accordance with other features of the present invention there are the following aspects. The base has a pressure plate on a front top surface that firmly engages an underside of the boot, and the pressure plate is slightly elevated above the rest of the top surface of the base and includes securing pins engageable in holes in the boot for retaining the boot in place. The member that releases the pair of support members includes a latch pin that extends through the base retained at its front end at the release lever and having a back end that engages and locks the pair of support members. A cross piece preferably extending between the lateral support members for engagement with the back end of the latch pin, the latch pin being tapered at its back end so as to displace when the lateral support members move downwardly, yet lock with the cross piece when fully engaged, a spring for biasing the latch pin toward a backward position, the base having a front to back passage for receiving the latch pin, and wherein the base comprises an outer metal shell and an inner plastic core that has the passage therein. A cross bar may be disposed between the pair of boot support members for engaging the front top of the boot and a pair of stop posts associated respectively with the pair of support members. 
   In accordance with still another aspect of the present invention there is provided a step-in binding for receiving a ski boot comprising: a base constructed and arranged to be secured to the ski and a pair of boot support members mounted from a front side of the base, and disposed laterally on either side of the base. The lateral side members are adapted to receive and guide the ski boot as it is received. The pair of boot support members are biased to a boot released position and further have a locked position that is assumed once the boot is received, engages the pair of boot support members, and is cantilevered downwardly into the locked position. A cross bar is disposed transversely between the pair of boot support members for engaging the front top of the boot over the duckbill. A release lever is mounted at the front of the base, readily accessible to the skier and includes a release member that releases the pair of boot support members from the locked position to the boot released position upon activation of the release lever. The lateral support members extend rearwardly from the center of the cross bar preferably by a distance of about 3.25 inches and in a range on the order of 2.0 to 4.5 inches. 
   In accordance with other features of the present invention there are the following aspects. A ski brake is integrated into the base, and constructed and arranged to urge the lateral support members from the locked position to the released position. The lateral side members are preferably tapered inwardly toward the front so as to receive and guide the ski boot as it is to be engaged. The member that releases the pair of support members includes a latch pin that extends through the base retained at its front end at the release lever and having a back end that engages and locks the pair of support members. 
   In accordance with still another aspect of the present invention there is provided a step-in binding for receiving a ski boot comprising a base constructed and arranged to be secured to the ski; and a boot support member supported from a front side of said base; The boot support member is biased to a boot receiving position and further has a locked position that is assumed once the boot is received, engages the boot support member, and is cantilevered downwardly into the locked position. A release lever is arranged at the front of the base, readily accessible to the skier and includes a member that releases the boot support member from the locked position to the boot receiving position upon activation of the release lever. A ski brake is integrated into the base, and constructed and arranged to urge the support member from the locked position to the released position. 
   Another feature relates to the position of the center of the cross bar relative to the toe box. The center of the cross bar receives the front of the toe box of the boot and the ends of the cross bar extend rearwardly by a distance of 0.75 inches in a range on the order of 0.25 to 1.75 inches. Also, the center of the cross bar is spaced rearwardly of the pivot axis of the lateral support members by a dimension of about 1.25 inches and in a range on the order of 0.75 to 2.25 inches. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of one embodiment of the binding of the present invention illustrated in the open position and with the ski brake extended; 
       FIG. 2  is a cross-sectional side view taken along line  2 — 2  of  FIG. 1 ; 
       FIG. 3  is a cross -sectional side view similar to that illustrated in  FIG. 2  but illustrating a boot engaged in the binding and with the binding being almost fully engaged or latched; 
       FIG. 4  is a cross-sectional view similar to that illustrated in  FIGS. 2 and 3  but illustrating the binding now in a fully latched position; 
       FIG. 5  is a top plan view of the binding as seen along line  5 — 5  of  FIG. 4  with the binding in its latched position; 
       FIG. 6  is a cross-sectional plan view of the binding taken along line  6 — 6  of  FIG. 4 ; 
       FIG. 7  is a cross-sectional end view of the binding taken along line  7 — 7  of  FIG. 4 ; 
       FIG. 8  is an exploded perspective view illustrating the components of the ski binding of the present invention; 
       FIG. 9  is a perspective view similar to that illustrated in  FIG. 1  but showing an alternate embodiment utilizing a rear mounted ski brake; 
       FIG. 10  is a perspective view of another embodiment of the binding of the present invention illustrated in the open position and with the ski brake extended; 
       FIG. 11  is a fragmentary perspective view of the toe of the ski boot; 
       FIG. 12  is a cross-sectional side view taken along line  12 — 12  of  FIG. 10 ; 
       FIG. 13  is a cross-sectional side view similar to that illustrated in  FIG. 12  but illustrating a boot engaged in the binding and with the binding being fully engaged or latched; 
       FIG. 14  is a cross-sectional end view of the binding taken along line  14 — 14  of  FIG. 13 ; 
       FIG. 14A  is a cross-sectional end view similar to the view of  FIG. 14  but illustrating an alternative design; 
       FIG. 15  is an enlarged fragmentary cross-sectional view taken along line  15 — 15  of  FIG. 14 ; 
       FIG. 15A  is fragmentary cross-sectional view of the alternative toe engagement design as taken along line  15 A— 15 A of  FIG. 14A ; 
       FIG. 16  is a top plan view of the binding as seen along line  16 — 16  of  FIG. 13  with the binding in its latched position; 
       FIG. 17  is a side elevation view of the binding of the present invention used with a heel retention piece; and 
       FIG. 18  is a plan view of the binding of  FIG. 17 . 
   

   DETAILED DESCRIPTION 
   The step-in binding of the present invention is primarily anticipated for use for Telemark skiing. A first embodiment of the binding is illustrated in  FIGS. 1–8 . An alternate ski brake construction is illustrated in  FIG. 9 .  FIGS. 10–16  illustrate another embodiment of the invention and  FIGS. 17 and 18  illustrate a heel retention piece useable with the binding of the present invention. 
   In the first embodiment described herein the binding  6  has a cantilever hinge or pivot arrangement that securely fastens the toe of the ski boot to the ski  8 . The binding of the present invention is constructed in a very simple manner with an effective mechanism for securing a Telemark boot to the ski, in a step-in manner. With the arrangement of the present invention a skier, in a standing position, inserts the toe of the ski boot under a cross-bar and steps down on the binding mechanism thus attaching the boot to the binding in a step-in fashion. The boot is released from the binding by pressing a release lever or toggle in the front of the binding using, for example, a ski pole. The binding has a simple and yet sturdy and effective design. A ski brake is integrated into the binding thus alleviating the need for ski runaway straps. 
   Now, with reference to the embodiment of the invention illustrated in  FIGS. 1–8 , the ski binding  6  is comprised of a center base or block  10  and a pair of boot support members  12 A and  12 B. The pair of boot support members is disposed laterally on either side of the base  10 . These support members  12 A and  12 B are pivotally supported from the base at a front of the base by means of the pivot pin  14 . A ski brake  16  is integrated into the base  10 . The ski brake  16  not only functions as a brake for a runaway ski, but also springs  18  associated therewith provide a biasing force for assisting and urging the binding from its locked position to its released position. The release of the binding is facilitated by the use of the release lever  20 . The release lever  20  operates the latch pin  22  which is biased by means of the latch pin spring  24 . 
   The base  10  is comprised of a main channel member  30  having a passage for receiving the plastic block  32 . The channel member  30  at its base wall has pairs of front and rear holes for receiving securing screws  35 , such as illustrated in  FIGS. 1 and 2  and for the purpose of securing the binding to the ski. The passage in the channel member  30  is dimensioned so as to snugly receive the plastic block  32 . Means may be provided for holding the block  32  within the passage in the channel member  30 . Such means may include screws  37  which also secure the pressure plate  36  to the channel member  30  as illustrated in  FIG. 7 . Other means may include an adhesive, or one can rely simply upon the close fit between the block and the channel member. 
   A pressure plate  36  is secured to the top surface at the front of the channel member  30 . The pressure plate  36  supports three boot alignment pins  38 .  FIG. 2  illustrates these alignment pins  38  in the corresponding holes  39  in the sole of the ski boot. It is noted that the pressure plate  36  is elevated above the top surface  33  of the channel member  30 . This assures that there is a good pressured fit of the boot to the pressure plate  36 . 
   The base  10  supports the ski brake  16  as well as the binding release mechanism. The center loop  16 A of the ski brake  16  is adapted for support within a lower slot in the plastic block  32 . In the assembly of the mechanism, the ski brake  16  is engaged with the block through the channel member passage  41 , as illustrated in  FIG. 8 . Opposite sides of the ski brake  16  also extend through respective holes  42  in the support members  12 A and  12 B. This inter-engagement between the ski brake  16  and the lateral support members  12 A and  12 B is instrumental in providing the releasing force for release of the binding from its locked position to its released position as illustrated in, for example,  FIG. 1 . Springs  18  disposed within the block  32  urge the ski brake  16  to the position illustrated in  FIGS. 1 and 2 , in other words its downward position. When the binding is moved to its locked position then the ski brake  16  rotates upwardly such as to the position illustrated in  FIG. 4  with the brake urging against the springs  18 . Note in  FIG. 4  the more compressed state of the springs  18 . 
   Also supported through the block  32  is the latch pin  22 . Block  32  has a front to back passage  23  for receiving the latch pin  22 . The rear end of the latch pin  22  is tapered as illustrated at  44 . A pin  46  is used, passing though the latch pin  22  at passage  47  so as to secure in position one end of the spring  24 . The very front end of the latch pin  22  is secured on the front side of the release lever  20  by means of a further pin  48  also passing through a hole at the front end of latch pin  22 . 
   As indicated previously, the lateral support members  12 A and  12 B are pivotally supported from the base  10  by means of the pivot pin  14 . The rear face of the release lever  20  is urged against pin  14 . The pin  14  also functions as a spacer between the support members  12 A and  12 B, and assures that there is correct spacing between the support members and the pin  14 . The pin  14  provides the main pivot for the lateral support members  12 A and  12 B and is attached to them by means of screws  50 , as depicted in  FIG. 8 . 
   The lateral support members  12 A and  12 B each have tapered sidewalls  52  that are adapted to guide the boot as it is inserted, such as the boot  55  illustrated in  FIG. 2 . Also refer to  FIG. 5  showing the convergence of the sidewalls  52 . The boot is also engaged under the crossbar  54 . The crossbar  54  preferably has a forward curvature so as to properly match the curved front of the ski boot.  FIG. 2  illustrates the sole  56  of the ski boot being engaged under the crossbar  54 . The crossbar  54  may be supported by screws  58 , as illustrated in  FIGS. 7 and 8 . At the rear of the support members there is also provided another set of screws  59  that supports a spacer bar  60  extending between the support members. The spacers  14 ,  54  and  60  control the distance between the lateral support members, particularly as it relates to the side-to-side dimensions of the aluminum channel member  30 .  FIGS. 5 and 6  illustrate this corresponding spacing which is relatively close and yet provides free rotation therebetween. The lateral support members also support at their respective front sides, each a stop pin  64 . The combination of these stop pins and the laterally directed walls  52  properly position the ski boot so that when the boot is moved to its locked position the boot is in proper alignment with the pins  38 . 
     FIGS. 1 and 2  illustrate the ski binding of the present invention in its released position. In that position the lateral support members  12 A and  12 B are pivoted to their most upward position and the ski brake  16  is in its most downward position. As indicated previously, the springs  18  bias the spring brake to this downward position. In this position the release lever is also shown in its rest position. In  FIG. 2  the boot has been inserted under the crossbar  54  and the skier is in readiness for engagement with the step-in binding. 
   The cross-sectional view of  FIG. 3  illustrates the ski boot being almost fully engaged by cantilevering the lateral support members toward their downward position by means of a downward pressure on the ski boot by the skier. In this view it is noted that the ski brake  16  has now moved to a more upward position against the bias of springs  18 . The spacer bar  60  is now being urged against the tapered end  44  of the latch pin  22 . However, in  FIG. 3  the binding is not yet in its fully latched position as the spacer bar  60  is still riding upon the tapered surface  44 . The ramping effect of the bar  60  against the tapered end  44  of the latch pin  22  causes the latch pin  22  to move in the direction of arrow  67 . It is also noted in  FIG. 3  that the release lever  20  has been moved toward a more downward position. Alternatively, when the boot is to be released from engagement with the binding, pushing down on the lever  20  with a ski pole or other means, causes a downward movement of the lever, which, in turn, causes the latch pin to move in the direction of arrow  67 . 
     FIG. 4  illustrates the binding now having been moved to its fully latched position. It is noted that in this position the spacer bar  60  has now moved under the latch pin  22 . This action secures the binding in this closed or locked position. In this position it is also noted in  FIG. 4  that the spring brake is in its full upward position and that the release lever has assumed its original position because the latch pin has now moved in the opposite direction indicated by arrow  69 . The pin  22  is urged in this direction by means of the spring  24 . 
   Reference is now made to  FIG. 9  for an alternate embodiment of the invention. This embodiment of the invention also employs a step-in binding. The binding itself  90  is substantially identical to the binding  6  illustrated in  FIGS. 1–8  with the exception that the binding illustrated in  FIG. 9  does not include the ski brake integrated into the binding. Instead, there is a separate ski brake  92  illustrated in  FIG. 9 . To accommodate this separate ski brake  92 , there is provided a connection of the ski brake at tubular member  94 . This ski brake  92 , like the ski brake  16  shown in  FIGS. 1–8 , biases the binding to a released position such as illustrated in  FIG. 9 . When the skier engages the binding and moves the lateral support members downwardly to a locked position, the ski brake center loop  92 A may also move downwardly against the bias of a spring means associated with the ski brake  92  rotating the ski brake  92  upwards. 
   It can be readily seen from the foregoing description, that the step-in binding of this invention is a relatively simple construction and, in the preferred embodiment, incorporates the ski brake into the binding. The ski brake actually functions both as a brake and as a means for assisting in releasing the binding by means of the bias of associated ski brake springs. 
   Another feature of the present invention is the relative flatness of the entire mechanism, particularly at the top surface  33  and at the surfaces that the boot rest upon on the lateral support members. By making these surfaces flat, there is far less of a likelihood of snow and ice buildup between the ski boot and the binding surfaces. 
   Another feature of the present invention is the use of a separate pressure plate elevated slightly above the surface  33  that enables a firm pressure contact with the boot, between the pressure plate  36  and the crossbar  54 . 
   Still another feature of the present invention is the preferred front positioning of the release lever. Many times release levers are disposed on the back of the binding and this makes it quite difficult to have access thereto. In accordance with the present invention the release lever is readily accessible at the front of the binding and preferably has an indentation therein to receive, for example, the end of a ski pole. 
   Another feature of the present invention relates to the simplified construction, such as the use of three crossbars that are used to unify the lateral support members. The front bar forms the hinge mechanism, the bar across the top of the boot holds the boot in place, and the rear bar locks the lateral member down. This locking down occurs between the spacer  60  and the pin  22 . Also, it is noted that the cross bars (spacers) abut to the inner surface of the lateral members thus maintaining the width necessary to receive the center block. These pins that support the bars or spacers are held in place with a screw through the lateral members and threaded into them. 
   Another embodiment of the present invention is shown in  FIGS. 10–14  in which further aspects of the ski binding are illustrated. Now, with reference to the embodiment of the invention illustrated in  FIGS. 10–14 , the ski binding  106  is comprised of a center base or block  110  and a pair of boot support members  112 A and  112 B. The pair of boot support members is disposed laterally on either side of the base  110 . These support members  112 A and  112 B are pivotally supported from the base at a front of the base by means of the pivot pin  114 . A ski brake  116  is integrated into the base  110 . The ski brake  116  not only functions as a brake for a runaway ski, but also springs  118  associated therewith provide a biasing force for assisting and urging the binding from its locked position to its released position. The release of the binding is facilitated by the use of the release lever  120 . The release lever  120  operates the latch pin  122  which is biased by means of the latch pin spring  124 . 
   The base  110  is comprised of a main channel member  130  having a passage for receiving the plastic block  132 . The channel member  130  at its base wall has pairs of front and rear holes for receiving securing screws  135 , such as illustrated in  FIG. 10  and for the purpose of securing the binding to the ski  108 . The passage in the channel member  130  is dimensioned so as to snugly receive the plastic block  132 . Means may be provided for holding the block  132  within the passage in the channel member  130 . Such means may include screws  137  which also secure the pressure plate  136  to the channel member  130  as illustrated in  FIG. 10 . Other means may include an adhesive, or one can rely simply upon the close fit between the block and the channel member. 
   The pressure plate  136  is secured to the top surface at the front of the channel member  130 . The pressure plate  136  supports three boot alignment pins  138 .  FIG. 13  illustrates these alignment pins  138  in the corresponding holes  139  in the sole of the ski boot when the boot is fully engaged. It is noted that the pressure plate  136  is elevated above the top surface  133  of the channel member  130 . This assures that there is a good pressured fit of the boot to the pressure plate  136 . 
   The base  110  supports the ski brake  116  as well as the binding release mechanism. The center loop  116 A of the ski brake  116  is adapted for support within a lower slot in the plastic block  132 . In the assembly of the mechanism, the ski brake  116  is engaged with the block through the channel member passage  141 , as illustrated in  FIGS. 10 ,  12  and  13 . Opposite sides of the ski brake  116  also extend through respective holes  142  in the support members  112 A and  112 B. This inter-engagement between the ski brake  116  and the lateral support members  112 A and  112 B is instrumental in providing the releasing force for release of the binding from its locked position to its released position as illustrated in, for example,  FIG. 13 . Springs  118  disposed within the block  132  urge the ski brake  116  to the position illustrated in  FIGS. 10 and 12 , in other words its downward position. When the binding is moved to its locked position then the ski brake  116  rotates upwardly such as to the position illustrated in  FIG. 13  with the brake urging against the springs  118 . Note in  FIG. 13  the more compressed state of the springs  118 . 
   Also supported through the block  132  is the latch pin  122 . Block  132  has a front to back passage  123  for receiving the latch pin  122 . The rear end of the latch pin  122  is tapered as illustrated at  144 . A pin  146  is used, passing though a hole in the latch pin  122  so as to secure in position one end of the spring  124 . The very front end of the latch pin  122  is secured on the front side of the release lever  120  by means of a further pin  148  also passing through a hole at the front end of latch pin  122 . 
   As indicated previously, the lateral support members  112 A and  112 B are pivotally supported from the base  110  by means of the pivot pin  114 . The rear face of the release lever  120  is urged against pin  114 . The pin  114  also functions as a spacer between the support members  112 A and  112 B, and assures that there is correct spacing between the support members and the pin  114 . The pin  114  provides the main pivot for the lateral support members  112 A and  112 B and is attached to them by means of screws  150 , as depicted in  FIG. 10 . 
   The lateral support members  112 A and  112 B each have tapered sidewalls  152  that are adapted to guide the boot as it is inserted, such as the boot  155  illustrated in  FIGS. 12 and 13 . Also refer to  FIG. 16  showing the convergence of the sidewalls  152 . The boot is also engaged under the crossbar  154 . The crossbar  154  preferably has a forward curvature so as to properly match the curved front of the ski boot.  FIG. 12  illustrates the sole  156  of the ski boot being engaged under the crossbar  154 . The crossbar  154  may be supported by screws  158 , as illustrated in  FIGS. 14 and 16 . At the rear of the support members there is also provided another set of screws  159  that supports a spacer bar  160  extending between the support members. The spacers  114 ,  154  and  160  control the distance between the lateral support members, particularly as it relates to the side-to-side dimensions of the aluminum channel member  130 .  FIG. 10  illustrates this corresponding spacing which is relatively close and yet provides free rotation therebetween. The lateral support members also support at their respective front sides, each a stop pin  164 . The combination of these stop pins and the laterally directed walls  152  properly position the ski boot so that when the boot is moved to its locked position the boot is in proper alignment with the pins  138 . 
     FIGS. 10 and 12  illustrate the ski binding of the present invention in its released position. In that position the lateral support members  112 A and  112 B are pivoted to their most upward position and the ski brake  116  is in its most downward position. As indicated previously, the springs  118  bias the spring brake to this downward position. In this position the release lever is also shown in its rest position. In  FIG. 12  the boot has been inserted under the crossbar  154  and the skier is in readiness for engagement with the step-in binding. 
   The cross-sectional view of  FIGS. 12 and 13  illustrates the action of the binding when applying downward pressure P on the rearward extension of the lateral members by the skier&#39;s boot. It is important to note the specific geometry and unified structure of the lateral members and the over riding cross bar, so that downward pressure at P directly translates into downward pressure under the crossbar  154 . This downward force under the crossbar  154  engages the sole of the ski boot with sufficient force to drive the pins  138 , a raised ridge or lip  131  shown in  FIGS. 10 ,  12  and  14 , and the adjustable set screw  161  at each end of the overriding cross bar  154 , as illustrated in  FIG. 10  or the hooked or ridged member illustrated in  FIG. 15A , securely into the sole of the ski boot. 
   The cross-sectional view of  FIG. 13  illustrates the ski boot being fully engaged by cantilevering the lateral support members toward their downward position by means of a downward pressure P on the ski boot by the skier. In this view it is noted that the ski brake  116  has now moved to an upward position against the bias of springs  118 . The spacer bar  160  has been urged against the tapered end  144  of the latch pin  122 . The ramping effect of the bar  160  against the tapered end  144  of the latch pin  122  causes the latch pin  122  to move in the direction of arrow  167 . The release lever  120  has been moved toward a more downward position. Alternatively, when the boot is to be released from engagement with the binding, pushing down on the lever  120  with a ski pole or other means, causes a downward movement of the lever, which, in turn, causes the latch pin to move in the direction of arrow  167 . 
     FIG. 13  illustrates the binding having been moved to its fully latched position. It is noted that in this position the spacer bar  160  has now moved under the latch pin  122 . This action secures the binding in this closed or locked position. In this position it is also noted in  FIG. 13  that the spring brake is in its full upward position and that the release lever has assumed its original position because the latch pin has now moved in the opposite direction. The pin  122  is urged in this direction by means of the spring  124 . 
   As indicated previously, the ski boot is locked to the binding by, inter alia, the pins  138  engaging in holes  139  in the sole of the ski boot. This interlocking is depicted in  FIG. 13 . In addition, the pressure plate  136  is preferably provided with a raised ridge or lip  131  shown in  FIGS. 10 ,  12  and  14 . This ridge or lip  131  may extend as shown in  FIG. 10  from one side to the other of the pressure plate  136 , and provides additional interlocking between the ski boot and binding. The bottom of the sole of the boot is sufficiently resilient so that the ridge  131  presses into the resilient sole material. Alternatively, the sole may be provided with a matching groove to receive the ridge or lip  131 . Alternatively, the ski boot may lock into the pressure plate with a raised ridge that conforms to the shape of the ski boot without the use of the pins  138 . 
     FIG. 10  illustrates, in addition to the stop pins  164 , a stop ridge  165  that is disclosed as formed as part of the pressure plate  136 . The ridge  165  is disposed at a right angle to the flat surface of the pressure plate  136 , and the very front surface  157  of the boot sole is urged against this ridge  165  when in the seated position such as illustrated in  FIG. 13 . The combination of the stop pins  164  and ridge  165  properly positions the sole of the ski boot for engagement with the pressure plate  136 . 
   The embodiment illustrated in  FIGS. 10–14  also has a further means for securing the ski boot in place. This includes providing an adjustable set screw  161  at each end of the overriding cross bar  154 , as illustrated in  FIG. 10 . Refer also to  FIG. 15  showing one of the set screws  161  screwed into the cross bar  154  but extending slightly below the lower surface of the cross bar so as to be engageable with a flat surface or indentation (see  166  in  FIG. 11 ) in the sole of the ski boot. Refer also to  FIGS. 11–13 . Adjacent to the position of the set screw  161 , as illustrated in  FIG. 15 , is an implanted metal stud  162  that is positioned in the sole of the boot, one on either side of the sole duckbill  168  as shown in the fragmentary perspective view of  FIG. 11 . Refer also to  FIGS. 12 and 13 , particularly  FIG. 13  where the set screw  161  is urged against the metal stud  162 .  FIG. 15  also depicts the engaged position where the set screw  161  is engaged against the implanted metal stud  162 . This arrangement provides for essential interlocking on both top and bottom surfaces of the boot sole, such as illustrated in  FIG. 13 . 
     FIG. 14  shows the embodiment in which there is provided the combination of a set screw and implanted stud. An alternate embodiment of interlocking is illustrated in  FIG. 14A  where the ends of the cross bar are each provided with a ridge or hooked end  169 . A cross-section of the hooked or ridged member is also illustrated in  FIG. 15A . This hooked end or ridge is meant to engage with the upper surface  170  of the duckbill portion of the boot sole (similarly to the ridge on the pressure plate from below the boot sole). The surface  170  may be provided with an indentation to receive the additional ridge of material  169  under the cross bar. 
   It should be noted that the adjustable set screws in the upper crossbar may have other purposes. In addition to engaging the sole of the ski boot the screw can be used to adjust the binding to fit the sole  156  of the ski boot  155  that may vary in thickness. 
   The embodiment of  FIGS. 10–14  is also characterized by important dimensional parameters. Some of these are illustrated in the cross-sectional view of  FIG. 13 . The dimension D 1  represents the length between the pivot at pin  114  and the very front of the toe box  172  as depicted by the line  171  in  FIG. 13 . The pivot at  114  is thus forward of the cross bar  154  and of the front of the toe box  172 . The dimension D 1  is preferably about 1.25 inches and may be in a range of 0.75 to 2.25 inches. The dimension D 2  represents the length between the front of the toe box (line  171  in  FIG. 13 ) and the end of the lateral support members  112 A and  112 B. The dimension D 2  is preferably at least 2.5 inches, may be about 3.25 inches and may be in a range of 2.0 to 4.5 inches. Also, the dimension measured from the front of the toe box to the bellows  173  may be on the order of 2.5 inches. The dimensional ratio of D 2  to D 1  is in a range between 2 to 1 and 3 to 1. 
   Reference is now made to  FIG. 14  for an illustration of other dimensional considerations. The dimension D 3  represents a length or height between the bottom of the cross bar  154  and the flat surface  174  of either of the lateral support members  112 A or  112 B. The dimension B represents a length or height between the bottom of the cross bar  154  and the top of the pressure plate  136 . The dimension A is slightly greater than the dimension B so as to enable ready initial placement of the boot into the binding and allow clearance for the set screw or ridge that extends from the overriding cross bar. 
   Reference is now made to  FIG. 16  for an illustration of other dimensional considerations. The dimension D 1 , as indicated before, indicates the distance between the front of the toe box and the pivot at  114 . The dimension D 3  represents a distance from the front of the toe box to the most rear portion  175  of the overriding cross bar member  154 . It is preferred to have the portion  175  as far back as is reasonably possible so as to provide proper grasping force by the cross bar against the boot sole. The dimension D 3  may be on the order of the dimension D 1 , but is usually less than the dimension D 1 . 
   The inter-relationship between of the dimensions and ratios, particularly as to the relationship between dimension D 1  and either dimension D 2  or dimension D 3 , is important to the action of the binding of the present invention. The length of the dimension D 2  is longer than either the dimension D 3  or the dimension D 1  to provide enough mechanical advantage (momentum arm) to fixedly lock the boot in place. The dimension D 2  extends rearwardly as far as practical to provide for the maximum lever force generated by the downward force of the boot when stepping down into the binding. If the dimension D 2  is too short, or in other words, under 2.0 inches there is not sufficient lever (force) action. The maximum length of dimension D 2  is limited by the fact that the boot sole curves up and no longer contacts the surface of the binding greater than about 4.5 inches back. The dimension D 2  is at least twice as long as either the dimension D 1  or the dimension D 3 . 
   The dimension D 3  as relates to the dimension D 2  provides the downward force on the duckbill  168  to effectively lock the boot in place. The rearward extension of dimension D 3  is important to spread the force on the top of the duckbill over a wider area and causes the boot to flex further back towards the bellows, as well as to provide an additional locking surface against the top of the boot sole. The dimension D 1  has some extension forward to provide enough upward rotation of the carriage (lateral support member and cross bar) when the binding is open to clear the raised pin plate  136  and pins  138  when inserting the duckbill into the binding but shorter than the dimension D 2  to generate mechanical advantage. As indicted previously, the binding ratio of dimension D 1  to dimension D 2  should be a minimum of 1:2. The rearward extension of dimension D 3  improves retention of the ski boot but is limited in length by the rearward extension of the duckbill and is shorter than dimension D 2  to maintain the mechanical advantage generated by the D 1 /D 2  geometry. 
   One feature of the present invention relates to the ease with which the boot can be engaged with the binding. In the position illustrated in  FIG. 12  with the binding open, the boot can be easily slid by the set screw or ridge  161 . This is possible by making the dimension A greater than the dimension B so that the boot readily slides into the lateral support members and under the cross bar. The very front of the support surface  174  for each support member may also be slightly dished out to provide additional clearance for the toe of the boot. 
   Another feature of the present invention relates to the positive engagement of the boot provided by retaining the boot from both above and below. This is possible with the use of the set screw or ridge  116  engaging the boot from above, and the pins  138  or ridge engaging the boot from below, thus providing a clamp like action on the ski boot. 
   Still another feature of the present invention relates to the positive camming and clamping aspect of the binding structure. The structure provides a vertical squeezing force generated between the center block (top surface  133  of the channel member  130 ) and the top cross bar  154  thus locking the duckbill  168  in place when stepping down on the laterally placed support members or wings  112 A and  112 B. This clamping feature is possible with the combined use of a carriage that is pivoted from a base piece. The carriage is fundamentally comprised of the two lateral support members  112 A and  112 B, and the overhead cross bar  154 . These carriage components can also be made as a unitary one piece structure, can be bent to shape or can be molded in a single piece. The pivot at pin  114  is forward of the cross bar  154  by the dimension D 1  (see  FIG. 13 ) measured from the front of the toe box. The pivoting occurs from the base block (channel member  130 ). The interaction of the lateral support members and cross bar hinged together at pivot  114  provides a cantilever action that locks the boot in the binding. 
   The carriage arrangement provides lateral support members  112 A and  112 B that extend rearwardly and on which the sole of the boot rests. These members are unified with the top cross bar  154  that overrides the duckbill of the boot sole, so that when the user steps down on the lateral wings, a downward force is created over the toe of the boot. The cross bar  154  drives the boot sole downwardly against the stationary center block and particularly the raised pressure plate  136  with a mechanical advantage and sufficient force to effectively retain the boot in place. 
   Another feature of the present invention relates to the enhancement of grasping ability of the binding against the boot by virtue of extending the ends of the cross bar where these ends merge into the lateral support members. This provides enhanced gripping of the boot sole. This is illustrated in, for example,  FIG. 16  where the end portion  175  extends rearwardly, represented by the dimension D 3  as measured from the line  171  (front of the toe box). The dimension D 3  may be in a range of 0.25 to 1.75 inches, and in the illustrated embodiment is about 0.75 inches. 
   A further feature of the present invention is the provision of stop pins, such as the pins  164  shown in  FIG. 10 . These pins not only position the forward position of the sole of the boot, but also these stop pins are positioned so as to locate the boot holes  139  in proper position relative to the three boot alignment pins  138 . This enables proper alignment of the boot with the pins  138  when the user is stepping into the binding, such as in the position illustrated in  FIG. 13 . 
   The binding illustrated in the previous embodiments may also be used with a heel retention member as is illustrated in  FIGS. 17 and 18 . In some instances it may be desirable to provide a heel piece for more secure ski boot retention and to change the performance characteristics of the ski binding. This heel retention piece complements the step-in feature characteristic of the ski binding of the present invention.  FIGS. 17 and 18  illustrate a relatively simple heel piece comprised of a heel clip assembly  204 . The boot  155  is shown inserted into the binding  206  that is, in turn, supported on the ski  108 . 
   The boot  155  is shown in  FIG. 17  as located in position in the binding with the boot heel  176  engaged with the tail end of the heel piece  204 . The curved heel engagement portion  282  of the shaped heel engagement member  280  engages with the ledge  177  on the heel  176 , as illustrated in  FIG. 17 . The shaped heel engagement member  280  rests on the heel lift block  178 . The heel clip assembly  204  is supported from the rear end of the lateral support members  112 A and  112 B, and more particularly from a lower upright wall of each member where the spacer bar  106  is supported therebetween, but just over the spacer bar  106 , as shown in  FIG. 17 . 
   The heel clip assembly  204  attaches to the rear of the lateral support members by means of the hooked ends  234  that extend through holes  240  in the side flanges. A series of holes  240  may be provided such as three holes illustrated in  FIG. 17 . The hooked ends  234  may be positioned in any one of the holes  240  to adjust the position of the heel clip assembly  204 . The shaped heel engagement member  280  then extends under the boot  155  to the rear of the boot where it is bent back toward the rear of the ski boot. The rear aspect of the heel assembly  204  is angled at approximately 45 degrees toward the ski boot to allow the heel of the ski boot to slide down this surface (curved boot engagement portion  282 ) and interlock with the ledge  177  when stepping into the ski binding. 
   The heel assembly  204  also includes a sliding spring mechanism that adjusts in length as a skier steps into the binding or as the boot is flexed forward into a telemark position. This mechanism includes threaded adjustable rods  228  having threads  229  that engage in the center block  226 . The aforementioned hooked ends  234  are at the ends of the threaded rods  228 . The combination of the center block and threaded rods enable adjustment of the relative position of the length of the heel assembly  204 . The length of the heel assembly is adjusted by turning the threaded hooked members of the assembly. Springs  284  are positioned by the spring retention hooks  286  and provide a bias for the heel clip assembly  204 . 
   Having now described a limited number of embodiments of the present invention, it should be now apparent to those skilled in the art that numerous embodiments, modifications and equivalents are contemplated as following within the scope of the present invention as defined by the appended claims. For example, the lateral boot support members and crossbar over the toe of the boot may be constructed as a single molded part that covers the whole front of the boot sole. Also, the lateral boot support members and upper cross bar could be constructed of bent sheet metal or injection molded material as a unitary part. The base of the binding and raised pressure plate could be molded as a unitary part. The outer channel member and inner plastic block that comprise the base could be a single molded part that then contains the spring pin and the ski brake. Use of this binding may include attachment of a heel retention device to the rear portion of the binding, or mounting this binding on a safety release plate. Heel retention devises and safety release plates are commercially available and of various designs.