Thermal, bi-modal heat-pump and cushioning shoe insole
Kind Code:

A bi-modal thermal insole heat pump and shock cushioner which can selectively be reversibly deployed in a shoe to act, with regard to its heat-pump capabilities, either as a heat-deliverer or as a heat-remover with respect to the underside of a user's foot.

Dennis, Michael R. (Scappoose, OR, US)
Monk, Russell A. (Salem, OR, US)
Application Number:
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Primary Class:
International Classes:
A43B7/02; A43B7/06; (IPC1-7): A43B7/02
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Primary Examiner:
Attorney, Agent or Firm:

We claim:

1. A bi-modal, reversibly and removably deployable, shoe-insole heat-pump structure in the form of a generally planar plural-layer assembly comprising a heat-delivery layer formed of a material wherein deliverable heat develops internally as a consequence of dynamic deformations that take place in the material during wearing use inside a shoe, said heat-delivery layer having one facial expanse defining a heat-delivery side for said heat-pump structure, and an opposite facial expanse, and a heat-removal, cooling layer formed of a low-surface-friction, moisture-wicking material having one facial expanse joined to said opposite facial expanse in said heat-delivery layer, and an opposite facial expanse defining a heat-removing side for said heat-pump structure, said layers, as joined into said assembly, having an appropriate, laterally reversible, left-shoe/right-shoe perimetral outline, depending upon which of the layers constitutes the upper, foot-engaging layer as installed removably in a shoe, whichever one of the layers that is deployed as the upper layer in a particular use installation determining whether the wearer experiences heating or cooling with regard to the assembly that includes that layer

2. The heat-pump structure of claim 1, wherein said heat-delivery layer is specifically formed of one or more acceleration-rate-sensitive material(s).

3. The heat-pump structure of claim 2, wherein said acceleration-rate-sensitive material is a viscoelastic material.



[0001] This application is a continuation from regular U.S. patent application Ser. No. 10/003,122. filed Nov. 14, 2001 for “Cushioning Shoe Insole”, which application, as does this continuation application also, claims priority to U.S. Provisional Application Ser. No. 60/281,604, filed Apr. 4, 2001 for “Cushioning Shoe Insole”. Both of these predecessor and serially copending patent applications are hereby incorporated into this application by reference.


[0002] This invention relates to a cushioning and thermally active shoe insole structure, and in particular to insole structure which functions as a reversible heat pump, depending upon insole orientation, within the confines of an otherwise conventional shoe.

[0003] A preferred embodiment of the invention is described herein in the form of a two-layer structure, one side of which can act advantageously as a heat-delivery side, and the opposite side in which can act as a heat-removal, or cooling, side.

[0004] Further, the invention focuses on such an insole structure which, in addition, performs as an extremely effective shock-absorbing mechanism in a shoe.

[0005] A preferred embodiment of the proposed heat-pump insole includes at least one acceleration-rate-sensitive (typically viscoelastic) layer having opposite facial expanses, to one of which expanses is bonded a low-friction, wear-resistant, moisture-wicking fabric material.

[0006] We have discovered that such an insole construction uniquely functions as a kind of reversible, passive heat pump, depending upon which side of the structure, inside a shoe during use, faces upwardly toward contact with the underside of a user's foot. Very specifically what we have discovered is that when a preferred structure like that just generally set forth above is employed inside a shoe, the uncovered “rate-sensitive” side, or surface, of the structure functions as a heat-delivery surface, and the opposite, moisture-wicking-fabric side, or surface, when facing upwardly inside a shoe, acts as a heat-removing and cooling surface.

[0007] While various acceleration-rate sensitive materials may be employed in the structure of this invention, so-called viscoelastic materials which fit within this category have been found to be very satisfactory. It is for this reason that a preferred embodiment of the invention is described herein in the context of such a viscoelastic material.

[0008] The various interesting features and important and unique advantages that are offered by the present invention will become more fully evident as the description that now follows is read in conjunction with the accompanying drawings.


[0009] FIG. 1 is a simplified plan view illustrating an isolated shoe insole which is constructed in accordance with the present invention.

[0010] FIG. 2 is an enlarged and fragmentary side elevation, taken generally along the line 2-2 in FIG. 1. The small insole fragment which appears at the right side of FIG. 2 illustrates a modified construction wherein a cushioning layer structure is made up of more than just a single specific material.

[0011] FIG. 3 is a view somewhat like that presented in FIG. 2, generally illustrating how the insole of FIGS. 1 and 2 responds, in relation to its shock-absorbing capabilities, to dynamic loading.

[0012] FIG. 4 is a simplified plan view of a pair of side-by-side insole heat-pump structures constructed in accordance with the present invention, placed inside left and right shoes (not shown) in such a fashion that the insole's upwardly facing sides are those sides which are formed by the fabric material mentioned above.

[0013] FIG. 5 is a simplified and stylized cross-sectional view, taken generally along the line 5-5 in FIG. 4, and employing two different styles of squiggly arrows to picture heat-flow activity engaged in by these insole heat-pump structures in accordance with this invention.

[0014] FIG. 6 is very similar to FIG. 4, except that here, the same two insole heat-pump structures have been turned over (top for bottom) and switched laterally (left to right) so that they now occupy a pair of shoes (not shown) wherein their upper surfaces are the viscoelastic-material surfaces mentioned above.

[0015] FIG. 7 is a simplified cross-sectional view, very much like that presented in FIG. 5, here also employing two different characters of squiggly arrows to illustrate heat-pump activity.


[0016] Turning attention now to the drawings, a preferred form of a proposed heat-pump insole structure (or insole) of this invention is indicated generally at 10. This insole is constructed in such a fashion that it is provided to a user in mirror-image pairs. As was generally described above, and as will be more filly described below, the two insoles in a given, supplied pair are essentially mirror-image copies of one another which can be placed (a) with one set of orientations in a left and right shoe with a common-structure upwardly facing surface, and (b) with another set of orientations flipped and reversibly placed in left and right shoes with common opposite facial structure then facing upwardly. With these insoles deployed so that their directly exposed, acceleration-rate-sensitive, viscoelastic sides face upwardly, the insoles act as heat deliverers to the underside of a user's feet. In the opposite orientation or deployment, flipped over and switched in a left-to-right manner, and with, now, the moisture-wicking fabric material facing upwardly, the insoles act as heat removers relative to the undersides of a user's feet.

[0017] In FIGS. 1, 2 and 3, only one mirror-image version of the proposed insole is illustrated. A description of this version will adequately suffice to describe the opposite mirror-image counterpart.

[0018] FIG. 4-7 inclusive illustrate matched pairs of insoles, and how they can be employed reversibly and bi-modally in accordance with the present invention.

[0019] Beginning, therefore, with a description of what is shown in FIG. 1, 2, and 3, insole 10 is preferably formed to be employable as a free insert for an already constructed shoe, and specifically to be an insert which will form-fittingly rest on the bottom inside surface of a shoe, with the perimetral outline of the insole substantially extending to the full perimetral outline of the inside exposed base area in the shoe.

[0020] Insole 10 includes a heat-flowable, anti-spring-back, shock (acceleration)-rate-sensitive cushioning layer 12, preferably formed of a material such as the micro-cellular, viscoelastic, urethane material known as Poron® 400 Performance Urethane Series 90, Formation #94. This particular material is manufactured by Rogers Corporation in Woodstock, Conn.

[0021] Layer 12, which has upper and lower surfaces 12a, 12b, respectively, as seen in FIG. 1, and which is formed preferably from a viscoelastic material like that just specifically identified, has an important behavioral pattern, or set of capabilities, whereby (a) it deforms in an acceleration-rate-sensitive manner (the greater the acceleration, the slower the responsive deflection), (b) it self-generates a significant amount of heat as it is subjected to repeated, normal-walking (or running), reversible deformation in use, (c) it returns slowly from such a deformation toward an undeformed condition without exhibiting any appreciable spring-like mannerisms, and (d) it delivers heat from its broad, outwardly facing, preferably uncovered surface expanse during its retarded return toward to a non-deformed state, and in fact, throughout the period of time that is it actually in use beneath a user's foot.

[0022] By way of contrast, and specifically discussing contrasts in relation to shock-cushioning behavior, an undesirable spring-action response to a deflection (which does not occur with respect to the behavior of layer 12) occurs where a material effectively reacts to, and tends to return from, a force-impact deflected condition with a felt return force, and in a time-frame, that generally match those of the event which has produced the subject deflection. A non-spring-like response, which importantly is characteristic of the behavior of layer 12, takes the form of a return (from a shock-force/impact deflection) that is retarded over time, and characterized by a lowered, overall-felt, return-force behavior. In a sense, a material behaving in this non-spring-like manner tends to “creep” back toward an undeformed condition, and this is precisely how the material which makes up layer 12 in accordance with the present invention behaves in the overall performance of insole 10. This behavior plays a significant role in minimizing the presence of localized high-pressure contact regions between a shoe, the insole and the underside of a user's foot.

[0023] Another important advantage which is offered by layer 12 in the insole is that it tends to flow (at a creep) with heat and compression, and thus tends to deform gradually to create an upwardly facing, topographically conforming, foot-support surface which tends to complement and follow the configuration of the underside of the supported foot. This behavior is what enables insole 10 to obviate high-pressure contact regions with a user's foot.

[0024] The exposed surface-expanse area of layer 12 which remains uncovered, so-to-speak, in the final preferred construction of insole 10 has a surface frictioning quality which, when stood upon directly (i.e., directly contacting the underside of a wearer's foot), plays an important role herein in the generating of friction-induced heat. This friction heat-generating facet of the behavior of layer 12, when coupled with the layer's above-mentioned propensity to “self-generate” heat as a consequence of repeated reversible deformations, offers, as the present invention proposes, a significant opportunity to employ the insole of this invention as a heat-delivering heat-pump.

[0025] Layer 12 herein has a thickness of about {fraction (3/16)}-inches. Variations in this thickness have a bearing on the heat-generating performance of layer 12, with thicker layers generally acting to generate more appreciable heat than thinner layers. Thus, thickness of this layer offers to designers a performance-variation option vis-a-vis heat delivery behavior.

[0026] The small fragment of insole 10 which appears at the right side of FIG. 2 illustrates a modified form of insole, wherein layer 12 includes two sub-layers 12c, 12d. Each of these layers is formed of an appropriate, through selectively somewhat different, viscoelastic material. This form of the insole provides a somewhat different kind of behavior, especially in relation to cushioning and shock-absorbing performance.

[0027] Suitably surface-bonded to surface 12a in layer 12 is a thin, fabric, moisture-wicking, low-surface-friction layer 14. Preferably, layer 14 is formed of a woven-fibre fabric material, such as that known as HEATHERSTONE®, made by Lee Fashion Fabrics, Inc., in Gloversville, N.Y. Fabric layer 14 herein has a thickness preferably of about {fraction (1/64)}-inches, and includes elongate, stretch-resistant fibres (see 14a in the figures) that function as tension-active, load-distributing components in the fabric.

[0028] Layer 14 plays several important cooperative roles (i.e., cooperative with layer 12) in insole 10. One of these roles involves furnishing a surface which has a low coefficient of sliding friction, so as to minimize friction heat development around the foot of a user during normal shoe use with layer 14 directly lying beneath a user's foot. Another role involves the wicking of moisture which typically develops in a shoe, and carrying this moisture efficiently to the side edges (perimeter) of the insole where that moisture can quickly evaporate, and in so doing, provide cooling within a shoe. Yet another role of layer 14 is that its fibres act as elongate load-distributing elements that aid in spreading localized load events to a broader area within the insole.

[0029] From the description of insole 10 which has just been given, it will be apparent that its opposite broad faces, one of which is defined by surface 12b in layer 12, and other of which is defined by the exposed surface expanse of the fabric material in layer 14, act bi-modally to deliverer or remove heat from the region of contact with the underside of a user's foot, depending upon which one of these surfaces faces upwardly in the manner that the insole is deployed in a shoe. An so, with insole 10 deployed in a shoe with fabric layer 14 facing upwardly, this insole acts as a cooling heat-pump. With this same insole flipped over, and deployed in the opposite-foot shoe, and with surface 12b of layer 12 facing upwardly beneath a user's foot, the insole acts like a heat-delivery heat-pump. Thus the insole offers the opportunity to provide bi-modal heat delivery or heat removal selectively, and under appropriate wearing conditions, all at the user's complete selection.

[0030] While the preferred construction of insole 10 is one wherein side 12b in layer 12 is completely uncovered, an additional modification of the invention involves employing a thin fabric layer over this surface as a modest modifier of heat-delivery activity. Such a thin layer of fabric, which can be thought of as being represented visually in FIG. 2 by a thin portion of the line therein designated with reference character 12a, can be employed to “tone down” the delivery of heat.

[0031] Offered by insole 10 of this invention, along with the just-expressed important heat-pump capabilities, are shock-handling qualities which will now be more fully described.

[0032] As was pointed out earlier, the material which makes up cushioning layer 12 responds to shock-force/impact loading in such a fashion that it has a tendency to return from a deformation (produced by such loading) in a retarded, slow and low-return-force (non-springy) fashion. This “low-return-force” behavior is evidenced by the material returning toward an undeformed (unshock-deformed) condition without displaying anywhere the same level of local return force or pressure which characterizes the initial loading per se.

[0033] FIG. 3 is expressly presented to highlight this important performance of layer 12 in insole 10. In solid lines in this figure, layers 12, 14 are shown representationally shock-deflected to produce the combined deformation generally indicated as a depression at D. Dash-double-dot-lines show the undeformed, prior dispositions of the local upper surfaces of these two layers.

[0034] Short, solid, downwardly-pointing arrow T1, and long, shaded, downwardly-pointing arrow F1 represent related time-span and applied-force characteristics, respectively, of the shock event which has produced deformation D. Long, solid, upwardly-pointing arrow T2, and short, shaded, upwardly pointing arrow F2, represent the related time-span and return-force characteristics, respectively, of how layer 12, in cooperation with layer 14, will try to return from the shock-deformed state. As can be seen, T2 is greater in length than is T1, and F1 is greater in length than is F2. These comparative and differentiated “lengths” represent the time-span and force-level behavioral characteristics which signal the kind of non-spring-factor cushioning response which produces the remarkable cushioning performance that is offered by the present invention. Fibers 14a, as indicated cooperatively by reversed arrows 16 in FIG. 3, act to distribute and spread load laterally in the insole.

[0035] On another point, the several outwardly pointing arrows which radiate from the letter M in FIG. 1 represent how moisture is wicked by layer 14 to the lateral (perimetral) edges of insole 10. At the perimeter of the insole, such wicked moisture readily evaporates, and introduces effective and noticeable cooling in a shoe equipped with the insole of this invention.

[0036] Shifting attention now to FIG. 4-7, inclusive, FIGS. 4 and 5 illustrate schematically and very simply two different points of view relating to two, mirror-image insoles 20, 22 which are formed with the construction described above for insole 10. These two insoles are deployed in left and right shoes, respectively, in FIGS. 4 and 5 and very specifically are deployed in such as fashion that their respective fabric sides 20a, 22a face upwardly to engage directly the undersides of a user's feet. The exposed viscoelastic sides of these two insoles, shown at 20b, 22b, are downwardly facing in the deployment pictured in FIGS. 4 and 5.

[0037] With this deployment of insoles 20, 22 in shoes (not shown), heat is removed from the region beneath a wearer's foot, such heat removal being indicated by broad squiggly arrows 24, and heat is vented, or pumped, outwardly and downwardly through the bottom viscoelastic sides of the insoles, as is indicated by pairs of squiggly arrows 26.

[0038] In FIGS. 6 and 7, matters are reversed. Here, insoles 20, 22 have been shifted left to right, placed in the opposite shoes respecting where they were as pictured in FIGS. 4 and 5, and have been turned over gravitationally so that their upper surfaces are now the viscoelastic surfaces. With this deployment of insoles 20, 22, heat is delivered upwardly to the underside of a user's feet, and is withdrawn from the region of the interface between the undersides 20a, 22a of the insoles and the bottom inside surfaces (upwardly facing but not shown) of the respective, associated shoes.

[0039] Insoles 20, 22 are preferably formed with perimetral outlines that are the mirror images of one another with respect to commonly facing broad expanse surfaces. They can easily be reversibly deployed, as was just described, in a user's shoes of the appropriate size, thus to give the user an opportunity to utilize the insoles either as heat-delivery heat-pumps, or as heat-removal heat-pumps, depending upon various conditions, and as selected by the user.

[0040] The insole structure thus proposed by the present invention offers some very special advantages in relation to conventional insoles. Its construction is quite simple, and it lends itself readily to incorporation removably in just about any conventional shoe design. By selecting the gravitational orientation of a pair of matched insoles, these insoles, when installed and in use, can act selectively either as heat-pump deliverers of heat, or as a heat-pump removers of heat. Heating of the material in layer 12 during normal use, and regardless of the gravitational orientation of that layer, causes the portion or the surface of the associated insole which directly contacts a user's foot to form fit with respect to the underside of the foot.

[0041] Acceleration-rate-sensitivity in layer 12 leads to significant anti-spring-back behavior, and contributes to a remarkable ability of the insole, in addition to acting as a versatile, reversible (or bi-modal) heat-pump, to cushion shock loads. Fabric layer 14 acts as a low-friction surface in the insole which is especially effective when the insole is deployed so as to remove heat from the region of interfacial contact between the insole and the user's foot. The moisture-wicking capability of layer 14 draws moisture away from beneath the foot, under circumstances with the foot engaging this layer, transporting that moisture to the perimeter of the insole, and thus promoting heat-removal cooling.

[0042] Accordingly, while the present invention has been disclosed in a particular setting, and with a particular structural form herein, it is appreciated that variations and modifications may be made without departing from the spirit of the invention.