Detailed description of the inventionAn example of a support customising systemaccording to the invention is illustrated in figures 1a and 1b. Figure 1adepicts a schematic cross-section of a shoe with a sole 1 comprising an outsole4, a midsole 3, bonded to the outsole 4, and a liner or insole 6 laid on theupper surface 7 of the midsole 3. The midsole 3 may be made of a resilientmaterial, for example an elastomer such as ethyl vinyl acetate (EVA) or othersuitable material. The outsole 4 may for example be constructed from a hard,resilient material such as rubber or polyurethane, and may have a hardnesswhich is greater than that of the midsole 3, at least at the ground-facingsurface of the outsole 4. The liner or insole 6 may be of relatively thinand/or softer material and serves to provide a comfortable surface for the soleof the wearer's foot. The liner or insole 6 may be removed to expose the uppersurface 7 of the midsole 3.
The example sole 1 illustrated in figure 1a isprovided with a plurality (six are shown) of vertical cavities 5, each of whichextends from the lower surface 15 of the midsole (ie the upper surface of theoutsole 4 in this example) up to the upper surface 7 of the midsole 3 along avertical axis 8. The midsole 3, apart from the holes (cavities 5) which areformed in it, may be constructed of continuous material, in order to ensure themechanical integrity of the sole as a whole. The vertical direction isunderstood in this text to be the vertical direction when the shoe is standingflat on level ground. The vertical axis 8 is thus substantially orthogonal tothe general plane 9 of the sole 1, which is taken to be generally parallel tothe upper, foot-facing surface 7 of the midsole 3 and/or to the lower,ground-facing surface 15 of the midsole 3, at least in the heel and/or midfootregions 13, 14 of the sole 1. The terms lower and upper used in thisdescription are also defined in terms of the vertical axis 8. Note that theterm vertical is used in this text to denote a general rather than a preciseorientation of the vertical cavities 2, and includes orientations which differby up to 15 degrees, or alternatively even up to 30 degrees from the verticalaxis 8 shown in figure 1a.
Figure 1b shows a set of inserts or plugs 5, alsoreferred to in this description as support adjustment inserts, which aredesigned for insertion into the cavities 2 in the midsole 3. In the exampleshown in figures 1a and 1b, the inserts 5 may be inserted into the cavities 2by first removing or raising the insole 6, and then pushing an insert 5 intoeach cavity 2 through insertion openings 10 in the upper surface 7 of themidsole. It is alternatively possible to configure the sole 1 such that theinserts 5 are inserted from below, through openings in the outsole 4. This hasthe advantage that the insertion openings 10 are more readily accessible. Analternative possibility is to provide insertion openings 10 in both the outsole4 and the upper surface 7 of the midsole 3, as discussed below.
The inserts 5 may also be made of an elastomericmaterial, for example, and they may have different hardnesses from the midsole3 and/or from one another. Some of the inserts 5 may have substantially thesame hardness as the material of the midsole 3, in order to provide a nullsupport adjustment at a particular cavity 2. It is also possible to provideinserts 5 with lower hardnesses than the midsole 3; this may for example beuseful for providing a negative support adjustment in a particular region ofthe sole 1 by reducing the average hardness of the region by inserting one ormore inserts 5 which are softer than the material of the surrounding midsole3.
The hardnesses of the inserts 5 may be selectedfrom a set of predetermined hardnesses. For example, a pair of shoes havingsoles such as that illustrated in figures 1a may be purchased with a set ofinserts 5 similar to those shown in figure 1b, with multiple alternativeinserts of different hardnesses available for insertion into each cavity, andwith each insert having one of a predetermined selection of hardnesses. Theremay be more inserts 5 in the set than there are cavities 2 in the sole 1. Themidsole 3 may have a hardness in the range 30 to 70 Shore, or 45 to 60 Shore,for example, and the supplied set of inserts 5 may include some inserts havinga hardness of 50 Shore, some of 60 Shore, some of 70 Shore, some of 80, 90 oreven 100 Shore, for example. Different inserts 5 of different hardnesses maythen be fitted into the cavities 2 provided, so as to achieve the desired localsupport hardness at each cavity location and collectively in each region of thesole 1 provided with cavities 2. If the midsole has a first durometer, then theset of inserts from which inserts can be selected for insertion into thecavities may include inserts, each of which may have one of a predeterminedplurality of durometers. The plurality of durometers may include durometerswhich differ from each other by between 5 and 20 Shore, including a durometerwhich is greater than the first durometer by between 5 and 40 Shore. As will bediscussed below, the plurality of durometers may include a durometer which isthe same as the first durometer and/or one or more durometers which are lessthan the first durometer. The first durometer of the midsole 3 may be constantfor all regions of the midsole 3, or it may vary between regions of the midsole3. In the latter case, the first durometer may either be taken to be an averagedurometer of the midsole 3 or a local durometer of a particular region of themidsole 3.
When the wearer puts weight on the sole, forexample while walking, the inserts 5 which are harder than the surroundingmidsole material serve to transfer a force from between the ground and thewearer's foot which is greater than that transferred by the surrounding midsolematerial. Each of these harder inserts thereby provides increased support forthe wearer's foot at the location in the sole at which it is inserted. Becausethe inserts 5 each have one of a predetermined set of hardnesses, at least inthe vertical direction, and because they extend along substantially the wholevertical depth 11 of the sole 1, or at least substantially the whole depth 11of the midsole 3, the net vertical hardness of the sole 1 at the location ofeach cavity 2 is determined exclusively, or in a great majority, by thehardness of the particular insert 5. The hardness of the outsole 4, if it isdifferent from the hardness of the insert 5, may also contribute an effect tothe net vertical hardness of the sole 1 at that location, but the contributionmay be small, particularly if the outsole 4 is thin and/or the hardnessdifference between the outsole 4 and the insert 5 is small. Similarly, thecontribution of the insole 6 or any minor part of the midsole which extendsabove or below the insert 5 when the insert 5 is inserted, will also have onlya small effect on the net vertical hardness of the sole 1 at the particularcavity. The term net vertical hardness is used here to indicate a measure ofthe compressibility and resilience of the sole in an approximately verticaldirection (ie as measured along the vertical axis 8).
The vertical cavities 2 and the inserts 5 shown inthe example of figures 1a and 1b have substantially parallel verticalside-walls. The cavities 2 may thus have a horizontal cross-section which issubstantially constant along their length 11, for example, or they may have atapering cross-section, any other shape which allows them to be fitted into thecavities 2 and/or subsequently removed for exchange. The horizontalcross-section of the cavities 2 and inserts 5 may be of any regular shape, suchas circular, oval, ovoid, hexagonal, triangular, square or rectangular, or itmay have have an irregular shape. The inserts 5 and cavities 2 areadvantageously dimensioned such that it is possible to fit two or morecavities/inserts into a particular gait control region of the sole 1, as willbe discussed below. In this respect the cavities and inserts 5 may be formedwith a horizontal cross-section which has a largest transverse dimension ofbetween 5mm and 30mm across, for example.
Because the inserts 5 are oriented substantiallyvertically in the midsole 3, and because they have relatively small lateraldimensions, multiple inserts 5 and cavities 2 can be located in a particularregion of the sole 1 in order to adjust the net vertical hardness of sole witha fine resolution. Thus, a pronation control zone in the forefoot area 12 ofthe sole 1 may incorporate multiple (eg three to ten inserts), for example,each with a hardness suitable for the pronation control requirement of thewearer. The hardnesses of the three to ten inserts 5 may be the same, or theymay be graded. For example, the hardnesses of the inserts may be increased fromthe rear-most insert 5 to the foremost insert 5.
The discussion above has related primarily to theinserts 5 and cavities 2 of a single shoe. In a pair of shoes, the inserts 5and cavities 2 may similarly be made so that the same inserts 5 can be used inthe cavities 2 of either shoe. The support customising system may be arrangedsuch that, multiple pairs of shoes can share the same set of support adjustmentinserts 5.
The use of multiple, interchangeable inserts 5having different hardnesses means that the support provided by the sole 1 canbe finely tuned to the needs of the wearer. The support may be differentlytuned between the left shoe and right shoe, between different regions 12, 13,14 of one sole 1, or even within the same region of the sole 1.
Figure 2 shows a plan view of a shoe sole 1 similarto the sole 1 shown in figure 1a, and shows in more detail how the supportadjustment inserts 5 can be arranged in the midsole 3 to achieve a customisedsupport, for example as an aid to gait correction for the wearer. Figure 2shows the midsole 3 of a right shoe, viewed from above, but it will beunderstood that the following description applies equally to a correspondingleft shoe, although the arrangement of inserts 5 may be different between theleft and right shoes.
In the example configuration of figure 2, the sole1 comprises a heel region 19, a heel medial region 21, a heel lateral region22, a forefoot region 23 and a metatarsal region 24. These regions are merelyexamples - other regions may be chosen. If there are multiple inserts 5 in eachregion, as shown, the support offered by the region as a whole can be adjustedprecisely by including individual inserts having different durometers - eitherto give an overall average hardness which is equivalent to an intermediatedurometer value between the available values of the available inserts, or togive a graded support across the region.
Left and right feet naturally have sightlydifferent pronation styles, due to the natural asymmetry in the person'sposture and due to neurological effects which gives rise to asymmetries ingross motor control, reflected in the person's posture and gait.
Because the inserts 5 of a particular region, or ofmultiple regions of the sole, may have the same cross-sectional shape, theinserts 5 may be made interchangeable between all cavities 2 of a particularregion or between all cavities 2 of the sole. In this case many differentconfigurations of the support offered by the sole can be achieved with arelatively modest number of inserts 5.
Each insert 5 may be formed as a single contiguouspiece of material, or it may be formed from two or more constituent pieces. Itmay be solid, for example to assure its rigidity, or it may be hollow, forexample to cut down on shoe weight and material costs. It may be open at one orboth ends, and it may have openings in its side wall(s).
Also illustrated in figure 2 is an ideal gait line20, also known as the stability axis or 'S-line', which indicates approximatelyhow the wearer's foot should pronate during its heel-to-toe contact (gaitcycle) with the ground. The example regions 19, 21, 22, 23, 24 are identifiedonly approximately, and are used to illustrate how inserts 5 in the variousregions can be used for controlling the wearer's gait.
The multiple cavities 2 may advantageously have thesame size and shape, as illustrated in figure 2. The inserts 5 of a particularset, even if they have different hardnesses, may also have the same size andshape, so that multiple inserts 5 of different hardnesses can beinterchangeably fitted into each cavity 2, and so that a particular insert 5can be fitted into multiple cavities 2. The hind-most heel part 19 of themidsole 3 in figure 2 is shown without any inserts 5 in this example. There maybe instances when it may be useful to be able to adjust the hardness of thishind-most region 19, but the illustrated example is designed to show how thesupport adjustment inserts 5 can be used for pronation/supination control, andthe hind-most region 19 of the midsole 3 serves primarily to cushion andcontrol the landing impact of the heel on the ground and the initial forwardmotion of the foot.
Medial and lateral control regions 21 and 22 can beused to control the amount of pronation during the initial phase of the gaitcycle (ie following initial heel impact). By judicious choice of the hardnessesof the inserts 51 of the medial region 21 and the hardnesses of theinserts 51 and 52 of the medial 21 and lateral 22 controlregions, it is possible to influence the degree of pronation of the foot aroundthe stability 'S-line' 20. Furthermore, the use of inserts 5 of gradedhardnesses in a particular region permits a second-order control, in which notonly the amount of pronation can be controlled, but also the rate of change ofpronation with respect to the forward motion of the foot during the sole'scontact with the ground when walking or running. Taking the six medial controlinserts 51 illustrated in figure 2 as an example, a first-orderpronation control can be obtained by selecting the hardness of the threeinserts 52 relative to the hardness of midsole 3 and/or of themedial control inserts 51. Harder lateral inserts 52 willencourage greater pronation, softer lateral inserts 52 will promotepronation less. However, by varying the difference between the durometers ofthe lateral inserts 52, it is possible to achieve a second-ordercontrol effect. If the hardness difference between inserts along the heel totoe direction is large, for example (ie the rear-most lateral insert52 is much harder than the forward-most lateral insert52, then the rate of pronation with respect to the foot's forwardmotion is greater. This means that the pronation occurs during a shorter time,when considered as proportion of the total contact time with the ground. On theother hand, if the hardness of the inserts 52 varies little alongthe heel to toe direction, then the pronation-enhancing effect with respect tothe foot's forward motion will be less. If the foremost lateral insert52 is harder than the rear-most insert 52, then this willact to reduce the rate of pronation.
The lateral and medial inserts 51 and52 can further be used to achieve a third-order control effect, inthat inserts can be selected to vary the rate of pronation. If the lateralcontrol region 22 is provided with more cavities and inserts 52,(say five inserts in a line running parallel to the heel-toe axis, forexample), then the hardnesses of the five lateral inserts 52 can bechosen so as to vary the rate pronation along the heel-to axis. Thus, by beingable to select the hardnesses of the lateral inserts 52 it ispossible not only to vary the amount of pronation (first-order effect), butalso to vary the rate at which pronation occurs (second order effect) and theaxial variation in the rate of pronation (third-order effect).
By using many cavities/inserts, it is possible tovary the pronation/supination control with a fine resolution, and in manydifferent ways. For example, it is possible to take set the hardness of theinserts 5 to take account of individual bones or bone groups in the foot.Excessive calcaneal/talal tilt can be compensated for, for example, whileminimising the effect on the metatarsal or forefoot regions.
The control effects described above in relation tothe interchangeable inserts 52 of the lateral region 22 also applyto the other illustrated regions in figure 2; the medial control region 21 withits multiple medial control inserts 51, and the forefoot controlregion 23, with its forefoot control inserts 53. A single mid-footcontrol insert 54 is illustrated in midfoot control region 24, whichmay be included in the midfoot /metatarsal region to discourage the wearer'sarch from sinking. The sole 1 may comprise such a single midfoot insert 24 onits own or in combination with one or more other inserts, as shown in figure 2,for example.
As a consequence of such finely-adjustable andadaptable gait control, it is possible to improve the wearer's gait andstraighten the wearer's axial skeleton, which not only has beneficial effectsfor the wearer, but also promotes even wear on the outsoles 4 and thereforeextends the life of the shoes.
Furthermore, if the individual inserts arereplaceable, then the soles can be 'tuned' for different uses, or for differentwearers, or as the shoes age, or as the wearer's gait changes.
The following examples illustrate the inserthardnesses which could be chosen for different gait control purposes. Theexamples are based on a sole configuration similar to that shown in figure 2,and the hardnesses given are relative to an example midsole material ofhardness 50 Shore. Where different inserts hardnesses are listed for aparticular region, these are listed on the order from rear-most tofore-most).
Example 1: for correcting a slightsupination
Lateral control region 22: 50 Shore, 60 Shore, 60Shore
Medial control region 21: all 50 Shore or less
Forefoot lateralcontrol region 23: all 60 Shore
Example 2: for correcting a delayed overpronation
Lateral control region 22: all 50 Shore (no correction)
Medialcontrol region 21: 50, 60, 70, 80, 80, 60 Shore
Forefoot lateral controlregion 23: all 60 Shore
Example 3: for correcting severe generaloverpronation
Lateral control region 22: 50, 50, 60 Shore
Medialcontrol region 21: 70, 80, 90, 80, 70, 60 Shore
Forefoot lateral controlregion 23: all 60 Shore
Example 4: for correcting early, slightoverpronation
Lateral control region 22: 50, 50, 60 Shore
Medialcontrol region 21: 70, 60, 50, 50, 50, 50 Shore
Forefoot lateral controlregion 23: 70, 60, 50, 50, 50 Shore
Example 5: for correcting delayed, slightoverpronation
Lateral control region 22: all 50 Shore (no correction)
Medial control region 21: 50, 50, 60, 60, 70, 70 Shore
Forefootlateral control region 23: all 50 Shore (no correction)
A second example sole layout is shown in figure 3.In this case, multiple inserts 55 are provided in the midfoot region13, in a midfoot pronation control region 25. Such an arrangement can be usedon its own or in addition to inserts in other regions 19, 21, 22 and/or 23 toinfluence the pronation from the lateral side to the medial side. Increasingthe hardnesses of inserts 55 from lateral to medial, for example,would help to slow the pronation rate in the midfoot area, while the pronationrate can be enhanced by decreasing the hardnesses of the inserts 55from the lateral towards the medial side. In the configuration of figure 3,inserts of two sizes are shown. In such a configuration the shoes couldtherefore be provided with two sets of inserts 51/ 52 and53/55, each set having inserts of multiplehardnesses.
Figures 4a to 4c illustrate example arrangementsfor the openings 10 of the cavities 2, as mentioned above in relation to figure1. In figure 4a, the cavity 2 comprises an opening 10 in the upper surface 7 ofthe midsole 3, and is closed at its lower end by outsole 4. In figure 4b, thecavity 2 is shown with an opening 10 in the outsole 4, and closed at its upperend by a small portion (eg less than 10% of the vertical thickness) of thematerial of the midsole 3. Figure 4c shows a third variant, wherein the cavity2 has an upper opening through the upper surface 7 of the midsole and a loweropening through the outsole 4, such that the inserts 5 can be inserted orreplaced via either end of the cavity 2. Thus in the variants shown in figures4b and 4c, the vertical cavity 2 extends through the lower surface 15 of themidsole 3 to the lower surface 15' of the outsole 4.
The inserts 5 may be secured in the cavities 2 byany suitable means. If an insert is intended to remain in its cavitypermanently, then it may be glued or bonded or welded in place in the cavity 2.The insert 5 may even be supplied as a liquid which can be introduced into thecavity 2 and which then sets with a predetermined hardness.
Figure 5 shows a variant of the system of theinvention in which a plate 16 is included over all or some of the inserts 5 inorder to delocalise the pressure which occurs between the foot and theindividual inserts 5. The plate 6 may be hard enough and flexible enough todistribute the pressure without influencing the effect of graded or variedhardnesses of the inserts. The plate 16 may optionally be recessed into theupper surface 7 of the midsole 3 as shown in figure 5.
Figure 6 shows three variants of cavities 2 whichare angled slightly from the vertical, in this case in a transverse direction.The vertical axes 81, 82 of one or more cavities 2 may beangled slightly outwardly or inwardly in order to enhance the effect of thechoice of insert hardness. Similarly, the cavities 2 of the forefoot region maybe angled slightly from the vertical as shown in figure 7.
The cavities 2 may also be angled in a longitudinaldirection, as shown in figure 8. In the illustrated example, six inserts 5 areshown having vertical axes 8' which are set at different angles α to the axis 8orthogonal to the principal plane of the sole. In this example, the rearmostinserts are angled rearward and the foremost inserts are angled forward,thereby enhancing a rolling or rocking in the gait of the wearer. With thisconfiguration it is thus possible to perform a pronation control as discussedabove, in addition to enhancing a rolling gait of the wearer. The tilt anglesmentioned here are preferably less than 30 degrees, or more preferably lessthan 15 degrees.
Inserts 5 may be made so that they can be pushedinto the midsole 3 by hand, for example. Figure 9a shows how the outer wall ofthe insert 5 may be provided with a positive-fit engagements means, in thiscase protrusions 25, which may engage with corresponding recesses 25' in thecavity wall, as shown in figure 9b. The protrusions 25 may alternatively bearranged in the cavity 2 and the recesses 25' on the insert 5. Alternatively,the protrusions 25 on the insert 5 wall may simply grip on the wall of thecavity 2 (insert 5) without the need for preformed recesses 25' in the cavitywall.
Figures 10a and 10b show an alternative arrangementfor securing the inserts in the cavities, in which the insert 5 is providedwith a thread 26 on its outer wall. The inner wall of the cavity 2 may beprovided with a corresponding thread 26'.
In order to insert and/or remove the inserts 5 intoor out of the cavities 2, the inserts 5 may be provided with pulling engagementmeans for withdrawing the insert by pulling, or rotational driving engagementmeans for screwing the insert 5 into or unscrewing the insert out of the cavity2. Two example arrangements are illustrated in figures 11a and 11b. Figure 11ashows how an end of an insert 5 can be provided with a recessed or otherwiseshaped grip 27 for providing a purchase when pulling the insert 5 out of itscavity 2. Figure 11b illustrates a slotted recess 28 for engagement with ascrewdriver or similar tool so that the threaded insert 5 can be screwed in orout of a cavity 2.
Figures 12a and 12b illustrate two examples of howan end of an insert 5 can be shaped so as to provide an enhanced gait-controleffect when located in a cavity 2. The insert 5 shown in figure 12a has arounded raised portion 29 which extends beyond that length 11 of the insert 5which will be accommodated by the cavity 2. The raised portion 29 can providean enhanced gait control effect if one or more such inserts 5 fitted in thesole 1 extend above the upper surface 7 of the midsole 3. The protrusion(s) mayextend up to 5mm or even up to 10mm above the surface 7 of the midsole 3, forexample. Such protrusions 29 are felt by the wearer's foot and engender aneffect known as sensomotoric loading-response, in which the foot alters itsorientation and movement in response to localised pressure from the protrusions29, and thereby influences the gait of the wearer.
Figure 12b shows an insert 5 having an angled uppersurface 30, which may be used for example to reinforce a direction ofpronation, as in the example shown in figure 13, which shows a rear-viewcross-section of a midsole 3 with medial and lateral inserts 5. The medialinsert 5 has a domed protrusion 29 for loading-response as described withreference to figure 12a, and the lateral insert 5 has an angled upper surface30 for enhanced pronation control. Such different types of protruding insertsmay be used separately or together, depending on the desired effect.
If an insert is made from two or more insertsub-pieces, then the individual sub-pieces may each form a portion of thecross-section of the insert, for example, each extending over the verticallength 11 of the insert 5, or they may each form a portion of the verticallength 11 of the insert, such that the insert 5 is formed from two or moreinsert sections arranged along the vertical axis. An example of such an insert5 is shown in figure 14a and 14b, and may comprise insert sections of differentvertical lengths and/or different hardnesses. Insert sections 5', 5'', 5''' ofdifferent hardnesses and/or vertical lengths may be combined in one insert inorder to provide the insert 5 with a particular required overall verticalhardness. Inserts and insert sections may be colour coded or otherwise markedin order to indicate their hardness, their vertical length, and/or theregion(s) of the sole for which they are intended. Different regions of thesole may be provided with inserts 5 of different cross-sectional shapes ordimensions, in which case different sets of inserts 5 or insert sections 5',5'', 5''' may be required for different regions of the sole 1. Alternatively,the vertical cavities 2 and the inserts 5 or insert sections 5', 5'', 5''' maybe sized and shaped such that each insert 5 fits each vertical cavity 2.
The compound insert 5 of figures 14a and 14b maythus comprise multiple pieces 5', 5'', 5''', which may be glued, bonded,screwed, clipped, or welded together, for example, or may be inserted andsecured in the cavity 2 separately. The pieces 5', 5'', 5''' may have differentheights and/or different hardnesses, so that a compound insert may be assemblywhose height and net vertical hardness height can be finely tuned by selectingappropriate pieces 5', 5'', 5'''.