fig1 shows a sectional side view of a ski binding heel unit 100 . the ski binding heel unit includes an upper heel housing 16 , lower heel housing 27 , heel pad 13 , lateral release 340 , interface support 330 , and vector decoupler mechanism 60 . heel pad 13 connects to interface support . the heel housing is disposed on the lateral release 340 , which is connected to the vector decoupler mechanism 60 . fig2 details a side view of the alpine ski binding heel unit shown in fig1 . upper heel housing 16 includes a pivot rod 18 , cam surfaces 19 a and 19 b stem section 17 b , lateral release cam assembly 17 , vertical release cam follower 20 , vertical release spring 21 , threaded cap 22 , window 24 , polymer piece 25 , surface 26 , region 33 , and heel cup assembly 47 . as used herein , the longitudinal and horizontal plane of the ski is that plane which is parallel to the bottom surface of the ski . the longitudinal and vertical plane of the ski is that plane which is perpendicular to the longitudinal and horizontal plane of the ski and parallel to the longitudinal centerline of the ski . upper heel housing 16 connects to lateral release cam 17 by way of a pivot rod 18 . vertical release is a function of opposing vertical release cam surfaces 19 a and 19 b on the aft - most end of the upper one - third stem section 17 b of lateral release cam 17 , and the vertical release cam follower 20 . the vertical release spring 21 ( shown by an “ x ”) in the large internal pocket of the upper heel housing 16 pushes cam follower 20 . forward release threaded cap 22 compresses the opposing end of spring . a window 24 on surface 26 registers the release adjustment value . in one embodiment , a transparent polymer piece 25 covers the window 24 . in a forward skiing fall , which generates a forward bending moment on the lower leg of the skier , the ski boot applies an upward vertical force to region 33 of the underside of heel cup 47 which heel cup is integral with upper heel housing 16 . the upper heel housing 16 holds and compresses a ski boot heel downward to oppose the upward forces generated by the ski boot during skiing . forces include those from forward bending moments and roll moments generated during edging because region 33 and pivot rod 18 have a lateral width to resist such induced roll moments from edging . the skier removes the ski boot from the alpine ski binding heel unit by applying downward pressure to the top end of upper heel housing 16 with the opposite ski , opposite boot , by ski pole , or by an open hand . cam follower 20 moves along the length of the pocket of the long axis of upper heel housing 16 in response to upward vertical forces being applied to region 33 or in response to downward exiting forces applied to the upper end of upper heel housing 16 . the shape of cam surfaces 19 a and 19 b control the relationship of the forces and corresponding displacement of cam follower 20 , as biased by spring 21 , which allows for the rotational displacement about a horizontal axis 18 of upper heel housing 16 and the vertical displacement of the ski boot in concert with region 33 . the vertical release cam follower 20 is made of plastic , while the moving lateral release cam 17 / 17 b is made of coated die cast metal or injection molded plastic , although other suitable materials known in the art may also be used . the vertical release cam interface between cam surfaces 19 a and 19 b can be heavily greased with moderately high viscosity low - friction grease such as molybdenum disulfide or the like . the wicking action of cam surfaces 19 a and 19 b , as in the way an eye - lid functions , preclude mud , road - salt and ice from interfering with smooth vertical release cam action . interface support 330 includes bottom surface , stop - lock / nut 29 , teeth 30 , longitudinal spring 32 , and lower carriage 12 . lower carriage 11 , connects to the top surface of a ski ( not shown ), to a riser plate ( not shown ), a lifter ( not shown ) or to an integral rail - system ( not shown ). stop - lock / nut 29 has one or more teeth 30 to allow selective movement of lower heel housing 27 along the length of lower carriage 12 in conjunction with slots 31 that are formed in lower carriage 12 . turning stop - lock / nut 29 facilitates movement of lower heel housing 27 relative to lower carriage 12 to properly fit various lengths of ski boots between the lower heel housing 27 and an alpine binding toe piece ( not shown ). in series with the stop - lock / nut 29 and lower heel housing 27 is longitudinal spring 32 , which provides a spring bias between lower heel housing 27 and lower carriage 12 . longitudinal spring 32 also provides longitudinal pressure between the lower heel housing 27 and alpine binding toe piece to ensure proper hold of a boot during the ski &# 39 ; s counter - flex . counter - flex increases the strain on the top surface of the ski , thereby increasing the distance between the toe piece and heel unit 100 . the longitudinal pressure maintains the contact of the binding &# 39 ; s toe piece and heel unit 100 throughout the ski counter - flex . the lower heel housing 27 applies longitudinal pressure to the ski boot via the upper heel housing 16 at surface 32 of heel cup 47 . an internal shoulder on stop - lock / nut 29 prevents the nut 29 from falling out of its opening at the end of the lower heel housing 27 . longitudinal pressure increases substantially during ski flex . such pressure is addressed by the longitudinal pressure spring biasing means that is comprised of elements 32 , 29 , 30 , 31 within lower heel housing 27 . the lower heel housing 27 fits to and integrates with lower carriage 12 by flanges 28 . specifically , flanges 28 a , 28 b , on each side of the lower heel housing 27 , mate with lower carriage 12 . heel pad 13 includes low - friction element 14 , low - friction surface 15 , and bearing grease 56 . low - friction element 14 is disposed on the heel pad 13 and is lubricated with bearing grease 56 . in an alternate embodiment low - friction surface 15 and bearing grease 56 is replaced with a low - friction surface 15 to which a boot can contact . low - friction means 14 and 15 provide smooth lateral heel release during combined downward - vertical and lateral stresses , which mitigate torque about the femur and correspondingly strained acl . low - friction means 14 and 15 contribute to rapid re - centering of the heel of a boot during innocuous lateral heel loads . the vector decoupler assembly 60 includes cantilevered plate 57 , vector decoupler tongue 60 a , top surface 61 , and low - friction elements 58 and 59 . the cantilevered plate 57 joins to the moving lateral release cam element 17 . the low friction elements 58 and 59 are made of a low - friction polymer , such as polytetrafluoroethylene ( ptfe ), or are made of other low - friction materials or surfaces that are already well known in the art . one side of the low - friction element 58 bonds to a mating surface ( not shown ). for example , the top - side of low - friction element 58 can be bonded to the bottom side of vector decoupler assembly 60 , allowing the low friction element 58 to slide while rotating and translating laterally . the translation occurs with the vector decoupler tongue 60 a when a force is applied to the vector decoupler tongue 60 a such that the vector decoupler tongue 60 a is applied against top surface 61 of lower heel housing 27 . optionally , the bottom side of low - friction element 58 can be bonded to the top surface 61 of lower heel housing 27 . accordingly , the vector decoupler tongue 60 can rotationally and translationally slide laterally against low friction element 58 . if the vector decoupler tongue is made of an aluminum die casting , a low friction coating ( such as teflon impregnated epoxy paint ) is applied to the contact surfaces of the vector decoupler tongue 60 a and the top surface 61 of the lower heel housing 27 . low friction coatings provide a low friction interface between the vector decoupler tongue 60 and the lower heel housing . if the vector decoupler tongue is made of injection molded plastic , the plastic material itself can be of a low coefficient of friction material without any coating , such as dupont delrin blended with ptfe , low - coefficient of friction grades of nylon 12 or nylon 66 or other low - coefficient of friction / high impact at low - temperature grades of plastics that are already well known in the art . in a similar way , the top - side of low - friction element 59 bonds to the bottom side of cantilevered plate 57 so that the vector decoupler tongue 60 a can slide smoothly while rotating and translating in the general lateral direction . or , optionally , the bottom side of low - friction element 59 can be bonded to the top surface of the vector decoupler tongue 60 a while the top surface of the low - friction element 59 slides by rotating and translating against the bottom side of the cantilevered plate 57 . if the vector decoupler tongue is made of die castable aluminum , low friction coatings , such as teflon impregnated epoxy paint , are applied to the contact surfaces of the vector decoupler tongue 60 a and the bottom surface of the cantilevered plate 57 . the application provides a low - friction interface between the vector decoupler tongue 60 a and the cantilevered plate 57 . the vector decoupler assembly 60 has sufficient width between 1 cm and 3 cm in the lateral direction . the augmented width resists a roll moment induced by a skier . the width also resists the stresses induced in the roll direction when skiing on snow or icy surfaces when a boot is forced to overturn laterally ( roll ), so that an upward unit force is applied to one side of the lateral region 33 of the underside of heel cup 47 thereby decoupling the effects of induced roll moments from the vertical release mechanism — minimizing inadvertent pre - release . the resistance supplied by the vector decoupler substantially decouples the roll moment from the moving lateral release cam surfaces 17 c and interfacing lateral release cam surfaces 27 a , thereby decoupling the effects of induced roll moments from the lateral heel release . the vector decoupler assembly 60 allows free lateral translational and rotational movement of the moving lateral release cam 17 relative to the lower heel housing 27 . the vector decoupler assembly 60 also allows free coupling of moving lateral release cam 17 against the mating cam surfaces 27 a in the presence of lateral heel release loads . this occurs even when induced roll moments and upward force vectors are applied through the vector decoupler assembly 60 . free coupling is partially limited by friction generated between the sliding surfaces of low - friction elements 58 and 59 and the respective mating surfaces of components 60 a and 61 . component 61 can be affixed to the lower heel housing 27 by band 18 that wraps around the lower heel housing 27 . in an alternate embodiment , cantilevered plate 61 is formed integrally with lower heel housing 27 as an aluminum die - casting or as an injection molded plastic part . the long length of vector decoupler tongue 60 a reduces the unit compressive stresses at the far end of the tongue , between its interfacing components , low - friction element 59 and cantilevered plate 61 during induced forward bending moments . the long length of vector decoupler tongue 60 also serves to reduce the compressive stresses between interfacing components , low friction element 58 , and the lower heel housing 27 during the latching action of stepping into the lower heel housing 27 . vector decoupler mechanism 60 above is de - coupled from longitudinal pressure loads generated between moving lateral release cam 17 and lower heel housing 27 , due to the longitudinally - open linkage between tongue 60 a and cantilevered plate 57 . in another embodiment , the side - to - side movement of the tongue 60 a may be limited either on one side or both sides and substantially restricted on one side to block lateral heel release in one lateral direction to cut the probability of lateral heel pre - release in half while at the same time allowing release in the other lateral direction to provide for the lateral stresses that cause the inward twisting abduction loads present in acl ruptures , described in part by the phantom - foot injury mechanism / fall mechanics described above . fig3 illustrates a sectional top view of a lateral heel release mechanism . fig4 shows the view of fig3 in greater detail . lateral release cam 17 is disposed next to matched cam interface 50 . both lateral release cam 17 and matched cam interface is disposed on top of lower carriage 12 . lateral release 340 includes lateral release cam 17 , matched cam interface 50 , spring biasing means 52 , lateral heel release spring 35 , tension shaft parts 36 a and 36 b , connector rod 41 , shaft - rod 37 , lateral release indicator washer 39 , internal washer 40 , integral opening 44 , rectangular opening washer 42 , and interface curved surfaces 51 a , 51 b , 51 c , 51 d , 51 f , 51 g . referring to fig2 and 4 , the lateral heel release mechanism comprises lateral release cam surfaces 17 c and lower heel housing lateral cam surfaces 27 a , which are biased ( i . e ., forced together ) by lateral heel spring - biasing component 52 . lateral spring biasing component 52 includes lateral heel release spring 35 that is placed in compression by the opposing force of the tension shaft parts , 36 a and 36 b ( or by optional unitary tension shaft 36 ), and connector rod 41 . these are supported at each tensioned two ends of the rod ( s ). at one end , shaft - rod 37 , lateral release cam 17 , and rectangular opening washer 42 support the equal and opposite compression against internal wall 43 of lower heel housing 27 . at the other end , lateral release threaded cap 38 , lateral release indicator washer 39 , internal washer 40 support the equal and opposite compression of the tension rod ( s ). internal opening 44 and the internal opening of rectangular opening washer 42 are both rectangular in shape to permit tension shaft 36 a ( or 36 ) to rotate and translate laterally upon the lateral movement of moving lateral release cam 17 . while the vertical gaps of internal opening 44 and the vertical gaps of rectangular opening washer 42 are each smaller than their respective lateral gaps , such vertical gaps restrict the vertical movement of tension shaft 36 a ( or 36 ), so that upper heel housing 16 provides vertical movement of the ski binding heel unit about its pivot axis 18 , rather than by the forced vertical movement of other elements . lateral heel release cam surfaces allow the lateral release cam 17 to both rotate and translate relative to the lower heel housing 27 , so that the heel area of the ski boot can displace laterally relative to the long axis of the ski . boot displacement occurs when lateral loads are induced . such lateral movement of the boot occurs across low - friction element 14 and heel pad top surface 15 , as well as laterally against heel cup 47 boot - interface surfaces 32 and 33 . the lateral release cam surfaces 17 c and 27 a of the lateral release cam 17 and the mating cam surfaces 27 a of the lower heel housing 27 displace relative to each other in a path described by their curved surfaces — specifically , curved surfaces 50 a , 50 b , 50 c , 50 d , 50 f , 50 g and their respective incremental interface curved surfaces 51 a , 51 b , 51 c , 51 d , 51 f , 51 g . a partial lateral boot heel displacement occurs when the projected longitudinal - pressure center - of - effort between the boot and the heel cup 47 shifts laterally and the moving lateral release cam 17 tilts by rotating and translating a small amount , biased by lateral heel release spring 35 . during such a partial lateral boot heel displacement , the opposing curved cam surfaces 50 a , 50 b , 50 c , 50 d , 50 f , 50 g move by translating and rotating ( tilting ) from their at - rest position to the next point of cam contact 50 c and 51 c , biased by lateral heel release spring 35 . accordingly , cam surfaces 50 b and 51 b space apart the “ a - a ” ( as in 50 a and 51 a ) surfaces from the “ c - c ” surfaces to provide an incremental lever arm . the incremental lever arm permits lateral translational and rotational movement of 17 relative to 27 a . the at - rest position is defined to be when the surfaces on the symmetrically opposite side of the lower heel housing 27 are touching each other . for example , the at - rest position occurs when surfaces 50 a and 51 a are contacting each other . as the heel of the boot continues to move laterally and lateral release cam 17 rotates and translates more to the point where cam surfaces “ c - c ” touch , a reverse - polarity lever - arm is generated that vector - adds to the spring bias effect of 52 . the resultant incrementally abates the rotational and translational movement of lateral release cam 17 . the abatement acts to re - center lateral release cam 17 toward its at - rest position , thereby providing incremental retention in the advent of large amounts of longitudinal pressure between the boot and lateral release cam 17 , which would otherwise cause inadvertent pre - release . if the lateral load at the heel persists in magnitude and / or and duration , the boot &# 39 ; s instant center of effort of longitudinal pressure then shifts outside of cam contact surfaces “ c - c ” to release the ski from the boot quickly and efficiently as is the case with acl injury producing loads . a similar benefit results if a load continues to persist in magnitude and duration while lateral release cam 17 continues to translate and rotate past the boot &# 39 ; s projected longitudinal pressure shifts “ outside ” of cam contact surface “ e - e .” this reverses the polarity of the lever arm that acts perpendicular to the boot &# 39 ; s projected center of effort of longitudinal pressure , thereby vector - subtracting from spring biasing means 52 to precipitate efficient release . cam surfaces “ f - f ” begin to separate as cam surfaces “ g - g ” contact one another . finally , when cam surfaces “ g - g ” contact and the boot &# 39 ; s projected instant center of longitudinal pressure shifts “ outside ” of cam surface contact point “ g - g ”, the perpendicular lever arm finally reverses polarity again to vector - subtract from the spring bias 52 , causing the moving lateral release cam 17 to rotate and translate toward lateral heel release . the novel incremental vector additions and subtractions along the progressive cam surfaces that progress from cam surfaces “ a - a ” to cam surfaces “ g - g ” as described above , are also progressively effected by the increasing overall lateral lever arm generated between those cam contact surfaces and the reaction force of spring bias 52 applied at the instant - center - of - effort of shaft - rod 37 . this arrangement makes lateral pre - release incrementally more difficult , the maximum point of release being a function of the exact spring constant of lateral heel spring 35 , the amount of compression of spring 35 as controlled by lateral release threaded cap 38 ( as indicated in lateral release level windows 53 on each side of lower heel housing 27 ). the maximum point of release is off - set by the incrementally decreasing longitudinal distance of the lever arm , between the lateral instant - center - of - contact of the side of the boot &# 39 ; s heel and the lateral heel cup surface 54 , to the instant - point of surface - contact on the progressive cam surfaces 17 c and 27 a . if the moving progressive cam 17 were to rotate only about a central pivot located over the center of the ski , the alpine binding heel unit 10 would be too biased toward release and skiers would suffer from pre - release . on the other hand , if the moving progressive can were to rotate only about opposing cam surfaces “ g - g ” ( as in 50 g and 51 g ) the alpine binding heel unit would be too biased toward retention and skiers would suffer from ruptured acl injuries . the progressive cams thus strike a decisive balance over release and retention by incrementally reversing polarity between release and retention during the course of lateral heel movement when moving cam 17 rotates and translates accordingly . the kinematics of the incremental lateral release path of the boot relative to the ski can be controlled by the geometry of the mating cam surfaces as noted above . adjustments to control the point of maximum lateral release can be adjusted by the compressive movement of lateral release threaded cap 38 . in one embodiment , a compressible elastomeric material 54 such as dupont crayton is placed between lateral release cam surfaces 27 a and 17 c to minimize the contamination effects of ice , mud and road - salt . alternatively , a very highly elastic membrane 55 can be placed at the open end of the surfaces as a barrier to such contaminants . in yet another embodiment , the gap between the surfaces can remain open and exposed so that visual inspection of the gap can be easily performed by skiers or service technicians and because of the curved end surface of 51 h . the curved end serves as a snow , ice and road - salt deflector to mitigate the practical effects of such environmental exposure . the entire lateral release mechanism including components 38 , 39 , 40 , can be easily removed from parts 35 , 36 a , 36 b , 41 , 42 , 37 and 17 to allow for periodic cleaning of the lateral release cam surfaces 17 c and 27 a . snow pack does not build - up and compress into ice in the gap between 17 c and 27 a because the lateral orientation of the gap is at right angles to the direction of travel through the snow , mitigating the practical and important concerns about snow - pack and ice formation and its interference with lateral heel release . low - friction journals , or integral surfaces 62 and 63 of moving lateral release cam 17 further serve to decouple induced roll and vertical loads when acting against surfaces 49 and 64 . they are , however , limited in their structural capacity due to the high unit stresses imposed on these surfaces . such stresses exist because of the necessary restricted longitudinal lengths of elements 62 , 63 , 49 and 64 , due to the need for the lower heel housing 27 to be compact in overall size , thereby causing the vector decoupler mechanism 60 to act in concert together with elements 62 , 63 , 49 and 64 to provide counter resistive fulcrum points as well as sliding bearing interface surfaces . other aspects , modifications , and embodiments are within the scope of the following claims .
ski binding heel unit includes lateral release cams and a vector decoupler mechanism that provide lateral shear release of the heel of a ski boot from a ski . the ski binding heel unit includes an independent vertical heel release mechanism , independent lateral release mechanism and a forward pressure compensator . the lateral release cams have laterally outwardly flaring contact points . the vector decoupler mechanism restricts heel unit lateral rotation and translation to a control path . the shape of the lateral release cams dictates the control path . the vector decoupler mechanism redirects the non - lateral forces without effecting the vertical heel release , lateral heel release or forward pressure compensator . the lateral release cams and vector decoupler mechanism avert non - lateral , benign loads from the lateral heel release , and avert non - vertical , benign loads from the vertical heel release thereby reducing the incidence of inadvertent pre - release of a boot from a ski .