GB2300558A - Shoe insole - Google Patents

Abstract

A shoe insole pack comprising a base insole layer 3 and substantially thicker heel section 2. The heel section 2 including an indentation 5 to accommodate one of the plurality of inserts 6 of different compressive resistance such that in use the insole will absorb percussive shock to varying degrees as required by the wearer of the footwear incorporating the insole. The inserts 6 are made from polyurethane foam and they achieve different compressibility quotients either by use of different types of foam or different thicknesses of foam. Most conveniently the indentation 5 has an asymmetric shape to mimic heel pressure distribution. The base insole layer 1 may be adhered to a separate heel section layer 2 using a heat activated latex adhesive. Furthermore, there may be applied to the other side of the base insole layer to the indentation a layer of wear resistant fabric.

Description

SHOE INSOLE The present invention relates to a shoe insole and more particularly but not exclusively to an insole for placement within a sports shoe to enhance shock absorbent performance.

A typical sports shoe comprises an upper secured to an injected polyurethane moulded sole with the interior of the shoe provided with suitable socking.

Such socking is provided to absorb sweat and give wear protection within the shoe.

It will be understood that in a sports environment it is advantageous for footwear to absorb at least some of the percussive shock as the wearer lands, runs or generally moves their feet. However, the footwear should not act as a dampening device which will inhibit or require additional physical effort over and above that required for a resilient shoe i.e. the footwear should provide a relatively stiff spring board whilst absorbing some of the impact shock and so reduce any potential injuries.

It has been known in the past to provide a polyurethane injection moulded outer sole having pockets to accommodate inserts in the waist of the shoe capable of altering the soles compressibility and thus shock absorbing ability. Unfortunately these inserts become worn in use and require replacement. Furthermore such an approach does not overcome the desire for snug foot location within the sports shoes necessary for comfort, and provide shock absorption in the heel of the shoe where it is most needed.

In sports shoes it will also be understood that the level of shock absorption performance necessarily varies from a amateur to a more professional athlete.

Traditionally, such variation has been accommodated if at all by variation of the outer sole compressibility and so different shoes might be necessary as the athlete becomes more proficient. This is expensive and requires that each time a new shoe is used that there must be another moulding stage in the insole to the wearer's actual foot shape.

It is an objective of the present invention to provide a shoe insole pack able to provide a range of shock absorbent configurations whilst allowing in situ moulding.

In accordance with the present invention there is provided an insole pack to affect shock absorbent performance of a shoe, the pack comprising a configured sole and a plurality of inserts having respectively different compressibility coefficients, the insole including a shaped base for location within a shoe, the shaped base having a heel support section, the heel support section including an indentation configured to enable one of said plurality of inserts to be releaseably located in the indentation in order to alter the compressibility of said support section and so shock absorption of the insole in the heel region, at least the configured insole being receptive to in situ deformation by a wearer's foot in use to substantially become moulded to said wearer's foot shape.

Preferably, the inserts are located within the indentation by friction fit or a pressure sensitive adhesive.

Preferably, the inserts are made of a Poron (registered trade mark) material i.e. a chemically frothed polyurethane foam having a shock absorbent range of 10 to 40 dura.

Preferably, the heel support section is a separate layer of foam with a compressibility quotient of 15 dura. The foam may be of a polyurethane or EVA type.

Preferably, the indentation has an oval shape or is asymmetrical in order to enhance performance by mimicking the heel weight distribution within a wearer's foot.

Preferably, the configured insole material is an EVA foam or EPDM synthetic rubber having a wear resistant fabric upon its top surface.

It will be understood that the insert compressibility can be adjusted either through inherent material performance design or by variation in thickness of insert with the same material type.

An embodiment of the present invention will now describe by way of example only with reference to the accompanying drawings in which Fig.1. is a schematic plan view of an insole with insert and Fig.2. is a schematic cross section of said insole.

Consider the drawings. A configured insole 1 is shaped to conform and allow insertion of the insole into a shoe. This base configured insole layer 1 is formed from most conveniently an EVA or EPDM synthetic rubber foam type material which will rapidly deform within a shoe to the wearer's foot shape.

In a heel region of the insole there is provided a heel support section 2. This heel support section 2 is generally thicker than the sole section 3 of the insole. The most convenient method of forming the sole configuration is to adhere a second or heel support layer of material to a first base layer 1. This heel support layer 2 can be formed from a polyurethane or EVA foam suitably shaped to conform with the base sole layer 1. Furthermore, for wearer comfort the transition zone formed between the base layer 1 and support layer 2 is skived to provide a sloped transition.

Within the heel support section 2 there is provided an indentation or recess 5. This indentation 5 can be of many shapes but is most conveniently asymmetrical along the line shown to mimic the weight distribution about the heel of a wearer's foot.

The recess 5 accommodates one of a plurality of inserts 6 formed from a resilient foam such as Poron (registered trade mark). The actual thickness of the insert 6 is determined by necessary performance, grade of material used and the desired shock absorption by a user.

Shock absorber materials such as Poron have been used as uniformly thick insoles previously.

However, the cost of Poron as a material has limited the practical thickness that can be applied and furthermore as the whole insole was formed of Poron the benefits of shock absorption in the heel section for a wearer have been limited.

It is at the core of the present invention that a range of inserts 6 are provided within an insole pack to enable a user to select an insole for his requirements from a plurality provided. Thus, the wearer can adopt his sports footwear to take account of his weight, sport, level of ability and any previous percussive shock induced injuries.

It has been found that provision of three inserts 6 within an insole pack can accommodate most users. This three insert pack would have inserts with shock absorbent response of 12, 20 and 30 dura. It will also be understood that a vast range of inserts could be provided as necessary and specific to different sports i.e. the requirements for tennis are different to basketball etc.

It will also be understood that in accordance with the present invention the heel section layer 2 is formed of a foam material such a polyurethane or EVA foams and most conveniently has a shock absorbing resilience less than the insert 6. Furthermore, the edge of the layer 2 is skived in order to facilitate in situ moulding by the wearer's foot in use.

It will be appreciated that in order to ensure adequate wear protection for the insole a top wear resistant fabric layer formed from either a non-woven or woven material is adhered to the base layer 1 on the opposite side to the indentation 5.

It is further in accordance with the present invention that a method of forming an insole is provided comprising the steps of: 1. Cutting a base insole layer 1 to a configuration for fitting within a wearer's shoe, 2. Cutting and skiving a heel section 2 having an indentation 5 which is substantially consistent with the base insole layer 1 about a heel region, 3. Adhering the heel section 2 to the base layer 1 through a suitable adhesive latex cement such as that sold by U.S.N TEXON Ltd as UNIFAST 1805, 4. Cutting a plurality of inserts 6 having differing compression resistance quotients but all capable of insertion within the indentation 5, 5. Placing in succession each insert into the recess 5 and determining the appropriate insert for a wearer's requirements.

It will be appreciated that prior to cutting the base layer 1 a suitable wear resistance fabric can be secured to the foam material in order to provide insole wear resistance in use.

The heel section 2 may be secured to the base layer 1 using a heat activated latex cement. The base layer 1 is coated with the latex cement and then preheated with contact heat for a sufficient time to activate the adhesive i.e. 100 degrees centigrade for 5 seconds however other temperatures and timings can be used.

It will be appreciated that it may be necessary to ensure that the wear resistant material layer applied to the base layer 1 has a barrier layer applied to it to prevent adhesive cement strike through upon shoe assembly.

The selected inserts 6 from the plurality provided in accordance with the present invention may be held within the recess 5 by friction fit or more conveniently using a pressure activated adhesive. It is at the core of the present invention that alternate insole inserts 6 may be place in the recess 5 as required by the wearer. Thus, the recess 5 must substantially retain its shape under compression consequently the heel section 2 must be formed of a sufficiently resilient foam to inhibit deformation of the recess 5. Furthermore the edge of the recess 5 may be sealed or lined in some way to maintain configuration during wear.

Typically the insole will have a thickness of 3.2mm and thus the indentation will have a depth of substantially the same dimensions. However it will be appreciated that it is not so much the thickness of the insert 6 but its compressibility that is required and so an insert 6 could be provided of the same compressibility material but of different thickness to provide the range necessary for accordance with the present insole pack.

It will be appreciated at the core of the present invention is the use of a limited amount of expensive compressive resilient polyurethane foam such as Poron (registered trade mark). Thus the benefit of a relatively thick layer of such polyurethane foam can be had in the heel area of footwear without providing either the same thickness of compressive resilient foam throughout the insole or skiving and thus wasting such foam in areas not necessary within the footwear. The types of polyurethane foam used are chemically frothed rather than mechanically to create the compressive resilience necessary.

Claims (11)

Claims:

1. An insole pack to affect shock absorption performance of a shoe, the pack comprises a configured base insole and a plurality of inserts having respectively different compressibility, the base insert including a shaped base for location within a shoe and having a heel support section, the heel support section including an indentation configured to enable one of said plurality of inserts to be releasably secured in the indentations in order to alter the compressibility of said heel section and so its shock absorption performance in use.

2. An insole pack as claimed in Claim 1 wherein the base insole is receptive to in situ deformation by a wearer's foot in use.

3. An insole pack as claimed in Claim 1 or 2 wherein an insole is held within the indentation by a friction fit or a suitable pressure activated adhesive.

4. An insole pack as claimed in Claim 1, 2 or 3 wherein the inserts are formed from a chemically frothed polyurethane foam such as Poron (Registered Trade Mark).

5. An insole pack as claimed in any previous claim wherein the heel support section is a separate layer of foam material adhered to the base sole by a suitable heat activated latex adhesive.

6. An insole pack as claimed in any proceeding claim wherein the indentation and thus each insert has an asymmetrical configuration to mimic weight distribution in use of a wearer's heel.

7. A method of forming an insole pack to affect shock absorption performance of a shoe comprising the steps of: A. Cutting a base insole from a layer of suitable foam material to a suitable shape for insertion within a shoe, B. Shaping a heel support section which is substantially configured to be consistent with the base sole layer in a heel section of the base layer, C. Forming an indention or hole in the heel support section of a desired configuration.

D. Cutting a plurality of inserts either from a range of chemically foamed polyurethane foams or by using a single polyurethane foam of varying thicknesses to give a range of inserts having different compressibility resilience,

8. A method as claimed in Claim 7 wherein the heel section is a separated layer of cut foam and is adhered to the base insole using a heat activated latex adhesive.

9. A method of forming an insole pack to affect shoe shock absorbent performance comprising,

1. Cutting a base insole of such a configuration for insertion within a shoe,

2. Skiving said base insole layer to provide a substantially thicker heel section,

3. Providing an indentation in said heel section,

4. Cutting a plurality of inserts having a range of compressive resistance either by selecting a plurality of different polyurethane foam types or using a single polyurethane foam type of varying thickness for each insert.

10. An insole pack substantially as herein before described with reference to the accompanying drawings.

11. A method substantially as herein before described with reference to the accompanying drawings