Patent Publication Number: US-2007114736-A1

Title: Multi-hinged skate and methods for construction of the same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This is a Continuation of application Ser. No. 10/429,202 filed May 2, 2003, which is a Continuation of application Ser. No. 10/151,976 filed May 20, 2002, and now U.S. Pat. No. 6,595,529, which is a Continuation of application Ser. No. 09/435,972 filed Nov. 8, 1999, and now U.S. Pat. No. 6,431,558, which is a Continuation of application Ser. No. 08/820,588 filed Mar. 19, 1997, and now abandonded, which in turn claims the benefit of Provisional Application No. 60/013,681 filed Mar. 19, 1996, each of the foregoing applications hereby incorporated by reference. 
    
    
     TECHNICAL FIELD  
      This invention pertains to boots for skates. In particular, it pertains to an improved hinge system connecting the lower boot to the upper boot cuff of an ice or in-line skate.  
     BACKGROUND ART  
      Skate boots for ice skates or in-line land based skates are well known. The majority of conventional skate boots are made from molded synthetic resins. Traditional molded in-line skates, as illustrated by  FIG. 1 , include a single pivot axis between the lower boot (which receives and constrains a foot) and an upper cuff (that grips the lower leg). The pivot axis is often a rivet-type connection on each side of the boot, providing a joint located in the vicinity of the anatomical ankle joint. Conventional boots allow for rotation of the ankle, called flexion—extension-extension (shown by the curved arrow in  FIG. 1 ). The boots are stiff in the lateral direction to provide support for maneuvering during skating. Unfortunately, the single pivot is difficult to locate exactly at the ankle joint, which is understood by those skilled in biomechanics to lie generally along an axis through the bony protuberances on the side of the ankle. The amount of force required to move the lower leg (the tibia) with respect to the ankle about this pivot axis during the skating motion (flexion—extension) can accordingly be more than it would otherwise be. The material of the boot must often be deformed to obtain a full range of motion for the user&#39;s ankle.  
      To complicate the problem, the anatomical pivot joint actually “floats” as the angle between the foot and the lower leg changes in the flexion—extension motion. More particularly, neither the lower leg nor the foot are made up of a single bone structure, and the connection between the foot and lower leg is more complicated than that of a simple hinge. The anatomical pivot point accordingly shifts in relationship to the axis through the bony protuberances on the side of the ankle as the angle of the foot relative to the lower leg shifts. A boot pivot axis created by a rivet-type connection, however, is fixed in the position of the rivet.  
      Another disadvantage of using the current rivet-type technology is that all of the load transferred at the pivot joint is concentrated at the pivots. The material around these pivots on both the upper cuff and the lower boot must accordingly be built up. While the extra material resists unwanted boot deflection due to longitudinal, lateral and torsion loads, it also results in more costly manufacture, heavier boots and concern for long term fatigue problems.  
      There are other problems and limitations with the current boot technology. The cuff must extend low enough to reach under the pivot axis, as well as extend high enough to grip the lower leg at a height that provides an adequate and comfortable lever arm. The lower boot must extend high enough above the pivot axis to support the pivot loads. Thus the cuff and lower boot have size and load requirements that add to the weight of the boot, add to the cost of manufacture, and adversely impact heat dissipation.  
      In fact, the design requirements of the single hinge approach to the flexion—extension issue restrict the number of options available to a boot designer. Once the cuff and lower boot height and weight considerations are met, there is little room for creative, alternative boot designs.  
      Most in-line skates have a rear mounted brake pad fixed to the lower boot behind the rear wheel. Braking occurs when the skater lifts the front of the skate off the rolling surface to engage the brake pad with the surface. More recently, movable brake mechanisms have been introduced, such as the two link chain extending between the cuff and the rear wheel comprising the brake depicted in  FIG. 1 . The rotation of the cuff clockwise relative to the boot (which is accomplished by the skater sliding a foot forward along the road surface while keeping the wheels on the road) will bring the brake pad in contact with the road surface. A shortcoming of the two link brake system, however, arises because two extra links must be added to the boot cuff and lower boot to realize the braking function. Also, the mechanical advantage of the two link brake is limited and nearly constant during braking.  
      A skate that would reduce the total weight of the boot, reduce the cost of manufacture, reduce the effort to rotate the ankle in flexion—extension during skating, and reduce the molded material surface and associated heat build up, would be a decided improvement to conventional designs. A new design that could incorporate flexures (living hinges) as substitutes for riveted joints would further reduce manufacturing costs. A new skate design would advantageously increase design options and should provide the ability to customize boots for a single person or a grouping of individuals based on leg, ankle and foot anatomy, and other preferences such as boot weight, anticipated use of the skates (recreational, racing, hockey, tricks, etc.), and the ankle strength of the user. Finally, an integrated brake design that avoided the problems of adding more complexity to the standard boot and limited control of the mechanical advantage would provide lower cost and safety, as well as other advantages over conventional systems.  
     SUMMARY OF THE INVENTION  
      The problems outlined above are in large measure addressed by the multi-hinged skate in accordance the present invention. The improved hinged system hereof does away with the traditional single jointed connections between the lower portion of the boot and the upper cuff of the boot, and presents in their stead several alternative forms of multi-link hinges that constrain the cuff movement relative to the lower boot. The method for constructing the multi-hinged skates can incorporate actual anatomical measurements into the design procedures, to provide for individually customized hinged systems. The multi-hinged design distributes the load between the boot cuff and boot lower portion, reducing individual pin loads as compared with a single hinged design, and provides for multiple design variations. The multi-hinged design hereof also provides for increased ventilation for cooling. The multi-hinge design incorporates a four link chain mechanism to control the motion between the upper cuff and the lower boot. The upper cuff and the lower boot account for two of the four links of the four link mechanism. The other two links are either rigid bars with pin connections on both the upper cuff and the lower portion, or roller links with a pin connection to the upper and a slot like sliding surface on the lower portion. One may also substitute a slider link for the roller and slide surface for the slot. The pin connection to the roller can be removed. The four link chain mechanism provides multiple advantages over the traditional, single hinge joint. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a side elevational view of a prior art skate including a single rivet hinge and a two link brake system;  
       FIG. 2  is a side elevational view of a skate according to the present invention depicted in the neutral (extended) position;  
       FIG. 3  is similar to  FIG. 2 , but with the skate upper depicted in the flexed position;  
       FIG. 4  is a side elevational view of a second embodiment of a skate in accordance with the present invention, with the skate upper depicted in the flexed position;  
       FIG. 5  is similar to  FIG. 4 , but with the upper depicted in the neutral position;  
       FIG. 6  is a side elevational view of a third embodiment of a skate in accordance with the present invention, with the skate upper depicted in the neutral position;  
       FIG. 7  is similar to  FIG. 6 , but with the upper depicted in the flexed position;  
       FIG. 8  is a side elevational view of a fourth embodiment of a skate in accordance with the present invention, with the skate depicted in the neutral position;  
       FIG. 9  is similar to  FIG. 8 , but with the skate depicted in the braking position;  
       FIG. 10  is a side elevational view of a fifth embodiment of a skate in accordance with the present invention, with the skate depicted in the neutral position;  
       FIG. 11  is similar to  FIG. 10 , but with the skate depicted in the braking position;  
       FIG. 12  is a schematic view of the skate of  FIG. 11 ;  
       FIG. 13  is a side elevational view of a sixth embodiment of a skate in accordance with the present invention, with the skate depicted in the braking position;  
       FIG. 14  is an enlarged, fragmentary view of an alternative brake construction;  
       FIG. 15  is a fragmentary view of a seventh embodiment of a skate in accordance with the present invention, depicting an alternative method of creating revolute joints;  
       FIG. 16  is a side elevational view of an eighth embodiment of a skate in accordance with the present invention, with the skate depicted in the flexed position, and with phantom lines depicting the upper cuff in the braking position;  
       FIG. 17  is a flow diagram depicting a boot design procedure in accordance with the present invention; and  
       FIG. 18  is a flow diagram depicting a design procedure for custom design of a boot in accordance with the present invention.  
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring now to the drawings, a skate boot  10  is illustrated in  FIGS. 2, 3  having a lower portion  12 , an upper cuff  14  and an intermediate portion  16 .  
      The lower portion  12  includes an undercarriage  22  and either rollers  32  for an in-line skate application or a blade (not shown) for an ice skate use. Lower portion  12  also includes inner padding  35 , a heal section  36 , a midsection  37 , a toe section  38 , one or more lower buckles  39  and a lower attachment section  40 . The lower attachment section  40  includes lower attachment points  54 . In the first embodiment of the present invention shown in  FIGS. 2 and 3 , lower attachment points  54  consist of revolute joints  60 ,  62 .  
      The upper cuff  14  includes an outer surface  51 , an upper attachment section  44 , inner padding  46 , an upper buckle  48 , a rear portion  49  and may include a downwardly extending Achilles tendon portion  49 A. The upper attachment section  44  includes upper attachment points  54 ′. Upper attachment points  54 ′ consist of revolute joints  64 ,  66  in the first embodiment of the present invention.  
      Intermediate portion  16  includes a pair of rigid members  50 ,  52  on each of the medial and lateral sides of the boot, that connect between lower portion  12  and upper cuff  14 .  
      The lower boot portion  12  holds the skater&#39;s foot in firm contact with skate boot  10 , especially the skater&#39;s heal, ankle and toe section, to help transfer desired skating forces and torques to the undercarriage  22  and wheels  32  or blade. The lower portion  12  is intended to be made of molded plastic based on methods well known in the art, but other materials or composites may also be used. There are many options for the shape of the lower portion  12 , particularly because the present invention is not restricted to a single hinged connection between the lower boot and the upper cuff. The lower boot can be reduced in size and weight as compared to prior art molded lowers, due to the innovative method of connecting an upper cuff to the lower portion.  
      The lower attachment section  40  of the first embodiment has two lower attachment points  60 ,  62  that serve to transfer the loads from the upper cuff  14 . As described in detail below, there are many permissible locations for lower attachment points  54 , providing multiple options to the designer for shaping the lower portion  12 , while meeting goals of lower weight, greater user comfort, reduced material volume, reduced manufacturing cost, reduced heat build-up, lower aerodynamic drag and improved appearance of skate boot  10 .  
      The lower portion  12  includes one or more buckles  309  that allow the foot to be inserted into and be secured in the lower portion  12 . The location and number of buckles is governed by the size of lower portion  12  and the loads required to keep the skater&#39;s foot secured in the lower portion  12 . It will be understood that lower buckles may be replaced with hook and pile attachments (or laces and eyelets) as are well known in the art.  
      The upper cuff  14  serves to comfortably grip the lower leg of the skater while transferring the motion and forces of the upper leg relative to the foot into skating motion. The outer surface  51  of upper cuff  14  serves as a rigid member that keeps its shape under load and impact so as to protect the lower leg, but at the same time have low weight with respect to prior art upper cuffs. The outer surface  51  may be made of molded plastics or equivalent. The optional Achilles tendon portion  49 A in the rear protects that part of the leg.  
      The upper cuff  14  includes one or more upper buckles  48  that are intended to allow the lower leg to be inserted into and secured to the upper cuff  14 . In  FIG. 2 , upper buckle  48  is shown in the front of upper cuff  14  but the buckle can be located elsewhere on the upper cuff. The upper buckles may be replaced with hook and pile attachments (laces and eyelets) as are well known in the art. The inner padding  46  serves to form a comfortable interface between the lower leg of the skater and the upper cuff  14  to reduce rubbing or irritation of the leg.  
      The upper attachment section  44  includes upper attachment points  54 ′. Upper attachment points  54 ′ consist of revolute joints  64 ,  66  that may assume a number of different locations. The loads on revolute joints  64 ,  66  are less than the loads on lower revolute joints  60 ,  62 , since lower revolute joints  60 ,  62  have a torque arm load not found on upper revolute joints  64 ,  66 . Thus the support material necessary for upper revolute joints  64 ,  66  is minimized and the subsequent additional weight to the upper cuff  14  is small.  
      The intermediate portion  16  of the first embodiment has been designed to guide upper cuff  14  relative to the lower portion  12  based on anatomical motion. The intermediate portion  16  includes rigid members  50 ,  52  that can have a variety of possible lengths. The shapes of rigid members  50 ,  52  are restricted only by the calculated locations of attachment points  54  and  54 ′. The three dimensional geometry of rigid members  50 ,  52  is accordingly a matter of the designer&#39;s choice, based on perceived force load, desired skate boot  10  shape and artistic look.  
      The four-bar linkage, such as employed in the present invention, is well known in the art as the smallest chain of links that can control the relative motion between two bodies. Lower portion  12  has rear first pin  60  and second pin  62  while upper cuff  14  includes second pin  64  and first pin  66 . In this particular design, rigid member  50  extends between first lower pin  60  and first upper cuff pin  66  while rigid member  52  extends between second lower pin  62  and second upper cuff pin  64 . These rigid members  50 ,  52  represent two of the four links of the four link chain. The other two links are the lower portion  12  and the upper cuff  14 .  
      The locations of lower attachment points  54 , upper attachment points  54 ′ and rigid member  50 ,  52  are advantageously determined through kinematic synthesis. Methods of kinematic synthesis can determine critical dimensions of linkage mechanisms based on desired motion inputs.  
      More particularly, the locations of attachment points  54  and  54 ′ and the lengths of rigid members  50 ,  52  can be determined by actual anatomical data that has been digitized (measured) from an actual person moving their leg relative to the ankle in flexion—extension motion, while the foot is constrained in a lower boot. Actual data from a typical skater is shown in TABLE 1, and was used in designing the embodiments depicted in  FIGS. 2-7 .  
      Table 1 represents the X, Y locations of points  70 ,  72  and  74  with respect to the rear wheel hub. The angles of the lower leg with respect to the horizontal axis pointing to the right and measured counter clockwise in the three measured positions are noted in the first column of Table 1. The first row of Table  1  is the most forward position  70 , at an angle of 137 degrees. The second row is the measured values for the intermediate position  72 , at an angle of 99 degrees. The third row is the measured values for the most extended position  74  at an angle of 75 degrees.  
      The LINCAGES software will convert the three prescribed planar design positions of Table 1 into many pairs of pins  60 ,  66  and  62 ,  64  that define rigid links  50  and  52 , through non-linear mathematical relationships known in the art (e.g. Mechanism Design: Analysis and Synthesis, Volumes 1 &amp; 2 by Erdman and Sandor published by Prentice Hall 1984, 1991 and 1997). The four bar linkage depicted in  FIG. 2  was developed with the LINCAGES software. It consists of the lower portion  12  as link  1 , rigid member  50  as link  2 , rigid member  52  as link  3 , and upper cuff  14  as link  4 . The shape of the upper cuff  14  is arbitrary and does not affect the relative motion between the upper cuff  14  and the lower portion  12  except to possibly limit motion due to interference. The important kinematic outputs from the kinematic synthesis are pin locations  54 ,  54 ′ and the first path tracer position  74 .  
      A different subject would create data that would be similar to that in TABLE 1, but differences in the relative Cartesian positions X and Y and angular orientations is to be expected due to normal variations in the human population. Such differences between subjects can be accounted for in the boot design according to the present invention, as described below.  
      The planar motion data of Table 1 may be converted into attachment point locations  54 ,  54 ′ on lower portion  12  and the upper cuff  14  receptively as well as rigid member  50 ,  52  lengths by methods of kinematic synthesis described in Mechanism Design textbooks such as Mechanism Design: Analysis and Synthesis, Volumes I &amp; 2 by Erdman and Sandor published by Prentice Hall 1984, 1991 and 1997, incorporated herein by reference. In these design texts, graphical and analytical methods are described that take relative position data and convert that data into possible four link chains that control the motion between the coupler link (in this case upper cuff  14 ) and a base (in this case lower portion  12 ). Kinematic synthesis is a general methodology that has been applied to many products such as windshield wipers, assembly equipment and landing gear, but never before to the design of a boot hinge. A well known kinematic synthesis commercial software package called LINCAGES (@ University of Minnesota), developed in part by me, was used in the design of the embodiments shown in  FIGS. 2-7 , and is incorporated herein by reference. Graphical methods of kinematic synthesis could also be used in the design of the mechanisms of  FIGS. 2-7 , or other designs.  
      The intermediate portion  16  of the first embodiment has been designed to guide upper cuff  14  through the positions shown in TABLE I using pin connections only. The locations of attachment point  54 ,  54 ′ determined through the LINCAGES software are shown in  FIG. 2 , along with rigid member  50 ,  52  relative lengths. It is understood that the same anatomical data can be met with many alternative attachment point locations  54 ,  54 ′ and member  50 ,  52  lengths but there is a calculated but non-linear relationship between attachment point locations  54 ,  54 ′. The alternative solutions can be determined through kinematic synthesis, either with the LINCAGES program, or through graphical networks. The choice of these solutions is left to the designer. The three specified design positions  70 ,  72 , and  74  listed in TABLE I are also shown in  FIG. 2 . The most forward (flexed) upper cuff  14  position  70 , the most back (extended) position  74  and an intermediate position  72  are shown as boxes with arrows  76  identifying the measured relative angular orientations of the leg and upper cuff  30 .  
      Lower portion  12  and upper cuff  14  have three dimensional geometry. For example, upper cuff  14  is generally a cylindrically shaped. Since the four-bar linkage moves in co-planar motion, and the desired motion data  88  of Table 1 is in the flexion-extension plane and the pins  54 ,  54 ′ Must have parallel axes (along the flexion—extension-extension axis), pin connections  54 ,  54 ′ Must be in the flexion—extension-extension plane. In this embodiment it would therefore be desirable to keep lower pin locations  54  away from the rear portion  36  of the lower portion  12  and to keep upper pin locations  54 ′ away from either the front or rear portion  49  of the upper cuff  14  to avoid adding material to build-up for connecting surfaces for these pins.  
      The lower supports the expected load of ice or inline skating. Rigid links  50 ,  52  transfer loads from the upper cuff  14  to the lower portion  12 . With two lower pins  60 ,  62 , the load is distributed, rather than concentrated at the one pin of the traditional molded boot. The local cross section of the mold can accordingly be reduced compared with the traditional molded boot.  
      Referring to  FIGS. 4 and 5 , the second embodiment of the present invention includes a lower portion  112 , an upper cuff  114  and an intermediate portion  116 . The lower portion  112  includes an undercarriage  122  and either rollers  132  for an in-line skate application or a blade  134  (not shown) for an ice skate use. Lower portion  112  also includes inner padding  135 , a heal section  136 , a midsection  137 , a toe section  138 , one or more lower buckles  139  and a lower attachment section  140 . In the second embodiment of the present invention, the lower attachment section  140  includes one lower revolute joint  160  on each side of the boot and a slot  170  (shown in  FIGS. 4, 5  in the cut away section  121  of lower attachment section  140 ) on each side of the boot.  
      The upper cuff  114  includes an upper attachment section  144 , inner padding  146 , an upper buckle  148 , an outer surface  149  and may include an Achilles tendon portion  149 A. The upper attachment section  144  includes upper attachment points  154 ′. Upper attachment points  154 ′ consist of revolute joints  164  and  166 .  
      Intermediate portion  116  includes an identical pair of rigid members  150  on the medial side and the lateral side of the boot that connect between lower portion  112  and upper cuff  114 . Intermediate portion  116  also includes a roller  152  on each side of the boot. It is recognized that the rollers  152  may be replaced by sliders or equivalent. For example,  FIG. 16  shows a slider  570  that replaces roller  152  in  FIGS. 4 and 5 . The roller  152  and slider  570  can guide the rear base of the upper cuff in slot  170  in the same fashion.  
      Similar to the above described first embodiment, the lower portion  112  holds the skaters foot in firm contact with skate boot  10 , and transfers desired skating forces and torques to the undercarriage  122  and wheels  132  or blade  134 . The lower attachment section  140  of the second embodiment differs from the first embodiment in that it has one lower attachment point at lower revolute joint  160  and one slot  170  on each side for receiving, the load transferred from the upper cuff  114 . There are a variety of permissible locations for lower revolute joint  160  and location of slot  170  that could be used by the designer in meeting the goals of lower weight, greater user comfort, reduced material volume, reduced manufacturing cost, reduced heat build-up, lower aerodynamic drag and/or artistic look of skate boot  10 .  
      The lower portion  112  includes one or more buckles  139  that allow the foot to be inserted into and secured to the lower portion  112 . The location and number of buckles would be governed by the size of lower portion  112  and the loads required to keep the skaters foot secured in the lower portion  112 . It is understood that lower buckles may be replaced with hook and pile connectors or laces and eyelets as are well known in the art.  
      The upper cuff  114  comfortably grips the lower leg of the skater and transfers the motion and forces of the upper leg relative to the foot into skating motion. The outer surface  149  of upper cuff  114  serves as a rigid member that keeps its shape under load and impact, protecting the lower leg but at the same time having low weight with respect to prior art upper cuffs. The outer surface  149  may be made of molded plastics or equivalent and may include an Achilles tendon portion  149 A in the rear to protect that part of the leg.  
      The upper cuff  114  includes one or more upper buckles  148  that are intended to allow the lower leg to be inserted into and secured to the upper cuff  114 .  
      In  FIG. 4 , upper buckle  148  is shown in the front of upper  114  but the buckle  148  can be located elsewhere on the upper cuff. The upper buckles may be replaced with hook and pile connectors or laces and eyelets as are well known in the art. The inner padding  146  serves to form a comfortable interface between the lower leg of the skater and the upper cuff  114  to reduce rubbing or irritation of the leg.  
      The upper attachment section  144  includes upper attachment points  154 ′. Upper attachment points  154 ′ consist of revolute joints  164 ,  166 . The location of the joints can vary, as described in detail below.  
      The intermediate portion  116  of the second embodiment is designed to guide upper cuff  114  relative to the lower portion  112  based on anatomical motion. The intermediate portion  116  includes rigid member  150  that has a variety of possible lengths and a roller  152  that has a variety of possible positions. The shape of rigid member  150  is restricted only by the selected locations of pins  160  and  166 . The three dimensional geometry of rigid member  150  is accordingly left to the designer based on perceived force load, boot shape and artistic look.  
      The locations of pins  160 ,  166 , slot  170  as well as rigid member  150  are again selected by methods of kinematic design called kinematic synthesis. Lower portion  112 , rigid member  150 , upper cuff  114  and roller  152  make up a four link chain of links which is different in form from that of the first embodiment. The form of the four link chain is sometimes called a crank-slider mechanism. The four bar chain of the second embodiment and depicted in  FIGS. 4 and 5  was determined from the same anatomical data of Table 1.  
      Planar motion data  88  may be converted into pin locations  160 ,  166  that define the end positions of rigid member  150  and the location of slot  170  by methods of kinematic synthesis described in Mechanism Design textbooks such as Mechanism Design: Analysis and Synthesis, Volumes I &amp; 2 by Erdman and Sandor. Either the LINCAGES software or graphical methods of kinematic synthesis can be used to determine pin and slot locations, and rigid member lengths.  
      The intermediate portion  116  of the second embodiment has been designed to guide upper cuff  114  through positions shown in TABLE 1 using pin and roller connections. The three specified design positions  70 ,  72 , and  74  listed in TABLE 1 are also shown in  FIG. 4, 5 . The most forward (flexed) upper cuff  14  position  70 , the most back (extended) position  74  and an intermediate position  72  are shown as boxes with arrows  76  identifying the relative angular orientations of the leg and upper cuff  114 .  
      The intermediate portion  116  includes an identical pair of rigid members  150  on the medial side and on the lateral side of the boot. A pair of rollers  152  on the medial side and the lateral side of the boot extend between the lower boot  112  and upper cuff  114 . Rollers  152  are connected with pins  164  to the upper cuff  114  and have contact with the lower boot  112  in slot  170 . Notice that the outside layer(s) of the lower  112  is cut away at line  121  to expose slot  170  in  FIGS. 4, 5 . The method of connection between members  150  and lower portion  112  and upper cuff  114  is by pins or rivets  160 ,  166 .  
      The locations of pins  160   166 , the lengths of rigid members  150 , the location of rollers  152  and the angle of slot  170  are determined according to the anatomical data of TABLE 1. In the depicted version of the second embodiment, the slot is straight and inclined. Roller  152  and slot  170  are kinetically equivalent to a very long rigid link that would have an equivalent lower pin connection in the direction perpendicular to the slot direction and a large distance away from the boot. For equivalent lower pin connections that are twenty or more times the wheel  132  diameter, the slot will be very straight. For lower pin connections less than ten times the wheel  132  diameter, the slot will be more curved such that the radius of curvature is the length of the equivalent rigid link. The shape of the upper cuff  114  is arbitrary and does not affect the relative motion between the upper cuff  114  and the lower boot  112  except to possibly limit motion due to interference. The important kinematic outputs from the kinematic synthesis are pin locations  160 ,  166 , roller  152  location, slot  170  angle and the first path tracer position  74 .  
      In this second embodiment, rigid link  150  and roller  152  will transfer loads from the upper cuff  114  to the lower  112 . The roller  152  and slot  170  are intended to carry most of the load so that the rigid links  150  may be designed accordingly and pin connection  160  will not have as much load.  
      Referring to  FIGS. 6 and 7 , the third embodiment includes a lower portion  212 , an upper cuff  214  and an intermediate portion  216 . The most significant difference between the third and second embodiment is that the lower attachment section  240  includes upper attachment points  254 ′ on each side of the boot consisting of slots  260  and  270  (shown in  FIG. 6, 7  in the cut away section  221  of lower attachment section  240 ) on each side of the boot.  
      The upper cuff  214  includes an upper attachment section  244  which includes upper attachment points  254 ′. Upper attachment points  254 ′ consist of revolute joints  264  and  266 .  
      Intermediate portion  216  includes rollers  250 ,  252  on each side of the boot. It is recognized that the rollers  250 ,  252  may be replaced by sliders or equivalent.  
      The lower attachment section  240  of the third embodiment includes slots  260 ,  270  that receive the load from the upper cuff  214  through the intermediate portion  216 . There are many permissible locations of slots  260 ,  270  which can be selected through kinematic synthesis.  
      The upper attachment section  214  includes upper attachment points  254 ′. Upper attachment points  254 ′ consist of revolute joints  264  and  266  that may assume a number of different locations.  
      The intermediate portion  216  of the third embodiment has been designed to guide upper cuff  214  relative to the lower portion  212  based on anatomical motion. The intermediate portion  216  includes rollers  250  and  252 .  
      The locations of pins  264 ,  266 , slots  260 ,  270  and rollers  250  and  252  are again selected through kinematic synthesis. Lower  212 , upper cuff  214  and rollers  250 ,  252  make up a four-bar chain of links which is different in form from that of the first and second embodiments. The four bar chain of the third embodiment (sometimes called a double-slider mechanism) corresponds to the same anatomical data of TABLE 1. In the third embodiment depicted in  FIGS. 6 and 7 , the slots are straight and inclined. The rollers and slots are again kinematically equivalent to very long rigid links that would have equivalent lower pin connections in the direction perpendicular to the slot direction and a large distance away from the boot. The shape of the upper cuff  214  is arbitrary and does not affect the relative motion between the upper cuff  214  and the lower  212  except to possibly limit motion due to interference. Appropriate pin locations  264 ,  266 , roller locations  250  and  252 , slot  260 ,  270  locations and angles and the first path tracer position  74 , as depicted in  FIG. 7 , can be determined through kinematic synthesis.  
      Rollers  250 ,  252  transfer loads from the upper cuff  214  to the lower boot  212 . The load is accordingly shared and distributed. Slider joints or equivalent may replace rollers  250 ,  252 .  
      A fourth embodiment of the boot design in accordance with the present invention is depicted in  FIGS. 8 and 9 . The fourth embodiment includes lower boot  312 , upper cuff  314  and intermediate portion  316 . Lower boot  312  includes lower attachment pivots  360 ,  362 . The upper cuff  314  includes upper attachment pivots  364 ,  366 , extension  368  and integral brake  370 . The integral brake  370  has a brake pad  372 , depicted in lower surface position  374  and  374 ′ respectively, in  FIGS. 8 and 9 , with respect to ground  376 .  
      The four link chain depicted in  FIGS. 8 and 9  is of the same type as introduced in  FIGS. 2, 3 , but with different dimensions. Upper cuff pivots  364  and  366  of  FIGS. 8 and 9  correspond to, but are at different locations, as compared to upper cuff pivots  64  and  66  of  FIGS. 2 and 3 . Also, lower pivots  360  and  362  correspond to, but are at different locations, as compared to lower pivots  60  and  62 . The pivots  360 ,  362 ,  364 , and  366  generate a four link chain designed to control the motion of the upper cuff  314  relative to the lower boot  312 . During the normal range of motion of the lower leg with respect to the foot while skating, brake pad lower surface  374  does not contact ground  376 . Intentional rotation of the lower leg, and thus upper cuff  314  clockwise relative to the lower  312 , however, (which is accomplished by the skater sliding their foot forward along the road surface while keeping the wheels on the road) will bring the brake pad lower surface  374 ′ in contact with the ground  376 , as depicted in  FIG. 9 .  
      Referring to  FIGS. 10, 11  and  12 , a fifth embodiment of the boot design in accordance with the present invention includes lower boot  412 , upper cuff  414 , and intermediate portion  416 . Lower boot  412  includes lower attachment pivots  460 ,  462 . The upper cuff  414  includes upper attachment pivots  464 ,  466 , buckle(s)  448 , inner padding  446 , rear portion  449 , and may include Achilles tendon portion  449 A.  
      The intermediate portion  416  includes rigid links  450 ,  452 , extension  468  of rigid link  450 , and integral brake  470  at the end of extension  468 . The integral brake  470  is shiftable between lower surface positions  474  and  474 ′, depicted in  FIGS. 10 and 11  respectively, with respect to ground  476 .  
      The four link chain shown in  FIGS. 10-12  is of the same type as introduced in  FIGS. 8, 9  and  FIGS. 2, 3 , but with different dimensions. Upper cuff pivots  464  and  466  of  FIGS. 10-12  correspond to, but are at different locations, as compared to upper cuff pivots  64  and  66  of  FIGS. 2 and 3 . Also, lower cuff pivots  460  and  462  correspond to, but are at different locations, as compared to lower cuff pivots  60  and  62 . The pivots  460 ,  462 ,  464 , and  466  comprise a four link chain designed to control the relative motion of the upper cuff  414  relative to the lower boot  412 . As the cuff is shifted by the lower leg clockwise with respect to the lower boot, the brake pad moves into contact with the ground ( FIG. 11 ). Referring to the schematic depiction of  FIG. 12 , the four-bar chain depicted in  FIGS. 10 through 12  presents a favorable motion trajectory ( 482 ) of the brake pad. The trajectory path of the tip  572  of the Coupler triangle represents the lower surface of the brake pad  472 . Note that this path is nearly perpendicular to the road surface  476  as the brake pad approaches the road surface  476 . As with previous embodiments, the embodiment of  FIGS. 10 and 12  can be developed with standard kinematic synthesis, employing the LINCAGES software, or graphical analysis.  
      The path of travel of the edge of the brake pad can also be determined by other methods, such as the use of instant centers. The method of instant centers can also be useful in the design of multi-link hinges. More particularly, the orientation of the pairs of rigid links are designed specifically to simulate the anatomical ankle joint—the center of rotation between the cuff and the lower boot is designed to be essentially at the same location as the human ankle. By Kennedy&#39;s theorem (See Mechanism Design: Analysis and Synthesis, referred to above and incorporated by reference) the instant center of rotation is at the intersection of the lines between the pivots of the two links. The four pivot locations can be changed to locate the simulated ankle joint in a specified region, but only a finite set of combinations will be acceptable. As the cuff moves relative to the lower boot, the crossing point will move some. The movement of this simulated ankle joint can be selected to match the shifting of the anatomical axis, and can be selected to positively affect the mechanical advantage of the skater during braking.  
      Note that there have been two integral brake systems depicted, one in  FIGS. 8, 9  and the other in  FIGS. 10-12 . In the first case, the brake is an extension of the upper cuff; in the second, the brake is an extension of one of the rigid links. The brake pad is connected to the forward-most link pairs  450  (one on each side of the boot). One reason for this is that the forward link moves at a higher angular velocity than cuff  414  and requires less cuff motion to engage the brake pad to the ground surface. The brake can be connected to any of the components that are moving with respect to the lower member. For example, the brake may also be connected to the roller (or slider)  164  of the embodiment in  FIGS. 4, 5  or either roller (or slider)  250 ,  252  of the embodiment in  FIGS. 6, 7 . Note that, in each of these cases, as the upper cuff moves clockwise towards its neutral position, the direction of movement of the roller (slider) is toward the ground.  
       FIGS. 13-14  depict a sixth embodiment of the boot in accordance with the present invention. The embodiment of  FIGS. 13-14  includes a three step braking system that is actuated by clockwise movement of the upper cuff relative to the lower portion.  FIGS. 13-14  depict the same multi-hinge design of  FIGS. 10, 11  but with a more advanced multi-stage brake that could as well be incorporated into the other depicted embodiments. This embodiment includes extension arm  468 , and brake pad  472 . Extension arm  468  includes cavity  490 , slot  496  and inner surface  498 . Cavity  490  includes spring  492  and parallel surfaces— 194 . Slot  496  has a pair of interference nubs  500 . Brake pad  472  includes lower surface  474 , upper parallel slide surfaces  476  and screw  478 .  
      The primary braking system is the same as has been described earlier: the extension arm  468  rotation is initiated by clockwise rotation of the upper cuff relative to the lower boot such that brake pad lower surface  474  comes in contact with the road surface  470 . Extension arm  468 , however, includes cavity  490  that houses spring  492  and, parallel surfaces  494  that accept brake pad  472 . Brake pad  472  includes upper parallel slide surfaces  476 , slidably received within extension arm parallel surfaces  494 . Screw  478  is inserted into brake pad  472 , fixing the brake pad  472  in the distal end of the extension arm  468  and against the force of spring  492 . Screw  478  is initially inserted into lower section of slot  496  below a pair of interference nubs  500 . During normal braking, spring  492  and nubs  500  hold the brake in the down position and provide enough normal force between the pad lower surface  474  and the road surface  470  for standard braking. The primary brake has compression spring  492  (or equivalent) plus nubs  500  between the extension arm  468  and the brake pad  472 . When the skater requires quicker deceleration, more force on the upper cuff will continue clockwise rotation of extension arm  468 . Spring  492  will compress and screw  478  will be forced past nubs  500  so that screw  478  will now be in the upper portion of slot  496 . As this occurs, brake pad  472  will slide up into cavity  490  as upper parallel slide surfaces  476  slide inside extension arm parallel surfaces  494 . This upward motion of brake pad  472  with respect to extension arm  468  shifts inner surface  498  into rear wheel  502 . Thus there is an “emergency brake” in which further clockwise rotation of the upper cuff beyond the initial road contact position will bring part of the extension arm  468  into contact with rear wheel  502 . This slows the rotation of rear wheel  502 . The rear wheel  502  will still have some rotation (although slower than that of the other wheels and slower than that required for keeping up with the road velocity at the point of contact of the rear wheel  502 ). This reduced rotational velocity will cause skidding (and therefore dissipate kinetic energy and speed), but the wear on the rear wheel  502  will be distributed around its periphery and not cause a flat spot in the rear wheel  502  surface. Full force on the cuff in the clockwise direction, however, could be extended to freeze the rotation of rear wheel  502 .  
      Inner surface  498  could alternatively come in contact with some other portion of the rear wheel assembly, such as part of the hub or the wheels rolling surface, for dissipation of kinetic energy.  
      The three step braking system described above includes: normal pressure on the upper cuff (which is accomplished by the skater sliding their foot forward along the road surface beyond the ankle motion required for normal skating) causing brake pad  472  to contact the road surface; further clockwise pressure that would trigger the extension arm  468  to contact with rear wheel  502  (but allow the rear wheel  502  to slowly rotate); and full clockwise rotation and that would completely stop the rotation of the rear wheel  502 . The brake pad is located on an extension of one of the four-bar links. The link extension can also include a “thumb wheel”  510  for extending the length of the link, to adjust for pad wear.  
      Referring to  FIG. 15 , a seventh embodiment of the present invention replaces one or more rivet type joints of the multi-hinge system with flexures. Since the relative rotations between the lower boot, the rigid links and the cuff are small, these joints can be fabricated as flexures (narrowed down portions in the mold) that concentrate the bending at the desired.  FIG. 15  depicts a portion of a skate boot similar to that depicted in  FIGS. 10 through 12 , but with the revolute joints  460 ,  464 ,  466 , and  462  replaced by flexures  520 ,  524 ,  526 , and  522 . The kinematic dimensions of the four link chain defined by the revolute joint  460 ,  464 ,  466 , and  462  locations are identical, it being understood that the centers of the narrowed down sections of flexures  520 ,  524 ,  526 , and  522  serve as the equivalent rivet locations. The advantages of this seventh embodiment include low cost, and an automatic return to the neutral position (if desired) when the force of the lower leg on the upper cuff is removed. Low cost is realized in part because a single mold can be employed for the three sections of the boot: the upper cuff, the lower boot and the intermediate section. Also, assembly cost and the extra cost of the rivets is saved.  
       FIG. 16  depicts an eighth embodiment of the present invention wherein a brake is incorporated within a slider link. The embodiment of  FIG. 16  has the same linkage geometry as depicted in  FIGS. 4 and 5 . As the upper cuff rotates clockwise, the slider moves diagonally downwardly and to the right, from the perspective of  FIG. 16 . The brake pad is accordingly brought into contact with the road surface. A spring or more rigid contact could be positioned between the cuff link and the break to provide greater torque on the brake pad. This is particularly the case since the angle between the upper cuff and the brake link decreases as the ankle extends towards the braking position. Thus a compression or torsional spring would store force to impart a transfer of load between the upper cuff and the brake link. Also, an extension of the upper cuff could make contact with the brake link to provide additional torque to the brake link, such as is indicated at E in  FIG. 16 .  
       FIG. 17  is a flow diagram that outlines a multi-hinge skate boot design procedure. The first step  700  is to determine end user needs based on the specific skating activity such as recreational in-line skating or street hockey. From this knowledge, the designer determines boot design constraints in second step  704  such as desired ankle movements along the three orthogonal axes and stiffness of the boot hinge system. The next step  706  is to measure actual anatomical motion of one or more humans and determine the resulting ankle range of motion in the specific skating activity that the boot is being designed for. From this information, step  708  requires selection of prescribed design positions (e.g. design positions  70 ,  72 ,  74  along with design angles  76  to create planar data  88  similar to Table 1). The selection of link joint types (pin, roller or slider) in step  710  is based on previous deliberations such as the desired skating activity in step  700  and determination of boot constraints in  704 . In some cases, a multi-hinged mechanism with pin joints may make sense where in other cases rollers or sliders may be more appropriate.  
      Next kinematic synthesis (step  712 ) is carried out by either analytical (such as using the LINCAGES software as described above) or graphical methods. Based on the kinematic synthesis method chosen, step  716  then includes surveying a number of potential solutions. From step  704  the design must extract desired boot characteristics such as the acceptable size constraints on the upper cuff and lower boot in step  714 . For street hockey usage, the desired outer boot surface area would be much larger than for a racing application for example. With inputs from steps  716  and  714 , step  718  is completed by specifying the specific height constraints of the cuff and lower boot. In step  720 , a specific multi-hinge linkage is chosen from the potential solutions generated in step  716 . Step  724  also follows step  714 , wherein detailed calculations are performed such as structural analysis (which could include bending and torsion deflection analysis and or finite element analysis). Also, experimental methods can be applied and manufacturing constraints should be considered. For example, based on the projected cost ceiling and volume of sales, certain methods of manufacture may or may not be appropriate. This realization will in turn dictate design decisions which must be applied to boot step  726  along with input from step  720 .  
      The boot system is prototyped and tested in step  728 , leading to an evaluation in step  730 . The designer will either accept and release the finished design to the market or reject it. If sufficient satisfaction is not reached, then modification is required. The process can actually then return to any of the previous steps of  FIG. 17 . The decision of how far one retreats in the multi-hinge skate boot design procedure depends on the time available and the level of dissatisfaction. For instance, the kinematic performance of the finished prototype of step  728  may be quite satisfactory but the lateral stiffness may be too high for the projected skating application of step  700 . In this instance the designer may only want to return as far as step  724 .  FIG. 17  is a general template for the multi-hinge skate boot design procedure; modification of the steps is anticipated in appropriate circumstances.  
       FIG. 18  is a second flow diagram, outlining a custom skate boot design procedure. The first step  800  is to determine end user needs based on projected skating activity such as recreational in-line skating or street hockey. During the second step  802 , the functional needs of skate users are sorted according to anticipated use and skill level. For example, the anticipated skill level may range from beginner to advanced recreational skaters; and general skating plus street hockey may be the projected uses. From this knowledge the designer determines boot design constraints for each sub grouping in the second step  804 . These constraints may include desired ankle movements along the three orthogonal axes and stiffness of the boot hinge system. The next step  806  is to measure actual anatomical motion of a human in each of these sub groupings. This will help determine the resulting range of motion of that human in each specific skating activity that the boot is being designed for.  
      From this information, step  808  requires selection of an initial set of prescribed design positions (e.g. design positions  70 ,  72 ,  74  along with design angles  76  to create planar data  88  similar to TABLE 1). The selection of link joint types (pin, roller or slider) in step  810  is based on previous deliberations such as the desired skating activity in step  800  and the boot constraints of  804 . In some cases, a multihinged mechanism with pin joints may make sense where in other cases rollers or sliders may be more appropriate. Next, kinematic synthesis (step  812 ) is carried out by either analytical methods (such a using the LINCAGES software as described above), or graphical methods. Based on the kinematic synthesis method chosen, step  816  includes surveying a number of potential solutions for the initial set of design positions. From step  804  the designer must extract desired boot characteristics for all uses anticipated in step  800  (such as the acceptable size constraints on the upper cuff and lower boot) in step  814 . With inputs from steps  816  and  814 , step  818  is completed when the specific height constraints of the cuff and lower boot are specified.  
      In step  820 , a specific (default) multi-hinge linkage is chosen from the potential solutions generated in step  816 . Alternative linkage configurations are selected in step  822  that satisfy the other needs identified in step  800 . This step has the objective of identifying adjustments in the multi-hinge system that help customize the hinge to a specific end user. These adjustments should be simple to make, such as moving, a single or a small number of pivot location(s) on either the upper cuff or lower portion to a new location. Other adjustments might include changing the angle of a slot or the location of that slot. Also possible is a change of length of one of the rigid links of the hinge. This determination can be done by standard kinematic analysis of the default multi-hinge system with a systematic change of one parameter at a time or other optimization methods known in the art. The result of step  822  will be a default and a number of alternative multi-hinge configurations in which the adjustment from the default design to any of the others is simple and prescribed.  
      Step  824  also follows step  814 , where detailed calculations are performed such as structural analysis (which could include bending and torsion deflection analysis and or finite element analysis). Also, experimental methods can be applied and manufacturing constraints should be considered. For example, based on the projected cost ceiling and volume of sales, certain methods of manufacture may or may not be appropriate. This realization will in turn dictate decisions which must be applied to the design of the boot in step  826 . Also input from step  822  will help in the design of the adjustment system necessary for customization of this boot system. The boot is prototyped and tested in step  828  leading to an evaluation in step  830 . The designer will either accept and release the finished design to the market or reject it. If sufficient satisfaction is not reached, then modification is required. The process can actually then return to any of the previous steps in  FIG. 18 . The decision of how far one retreats in the multi-hinge skate boot design procedure depends on the time available and the level of dissatisfaction. For instance, the kinematic performance of the finished prototype of step  828  may be quite satisfactory but the lateral stiffness may be too high for the projected skating application of step  800 . In this instance, the designer may only want to return as far as step  824 .  
      An end user would be asked questions about their skill level and the desired use of the skate boot at the place of purchase (step  832 ). The skater may even be tested (either range of motion or ankle strength or both). Based on these determinations, the multi-hinge is custom adjusted for that end user in step  834  (with input from the analysis done previously in step  826 ). It is also possible that the end user could be provided information of how to adjust the multi-hinge system for a change of skating activity, or for an alternate user such as in a rental situation.  FIG. 18  is a general template for a custom skate boot design procedure which includes adjustable hinges; modification of the steps is anticipated in appropriate circumstances.  
      The present invention can include additions to the above embodiments, such as built-in limit stops in the lower boot to limit the range of motion of the multi-hinge system at either or both ends of the flexion—extension motion. Inner boots are well known in the art and are assumed possible additions. The addition of springs or spring elements between the lower boot and one or more members of the multi-hinge system is anticipated if assist is required (for example in the instance of spring return to a neutral position for the flex hinge embodiment in  FIG. 16 ).  
                       TABLE 1                       CUFF ANGLE   X LOCATION   Y LOCATION                  137 DEGREES    8.3 INCHES    9.6 INCHES 70       99 DEGREES   4.0 INCHES   12.3 INCHES 72       75 DEGREES   0.7 INCHES   12.7 INCHES 74