WO2000030486A1

WO2000030486A1 - Improvements in or relating to footwear

Info

Publication number: WO2000030486A1
Application number: PCT/GB1999/003845
Authority: WO
Inventors: Nicholas James Pearson
Original assignee: Gas Injection Limited
Priority date: 1998-11-20
Filing date: 1999-11-19
Publication date: 2000-06-02
Also published as: AU1394200A; GB9825348D0

Abstract

A moulded footwear component adapted to form an insert (1) in an item of footwear comprises a moulded body having a plurality of internal strengthening ribs and a plurality of internal cavities disposed to provide different degrees of resistance to pressure from different parts of a wearer's foot. The component is moulded by gas assisted injection moulding and an external layer may be moulded around the insert or fixed to it in some other way. Formations are provided on the component to enable it to be keyed to the external layer. The external layer is shaped and patterned according to current fashion requirements and forms a subassembly with the insert for a heel, sole or combined sole and heel for the item of footwear.

Description

IMPROVEMENTS IN OR RELATING TO FOOTWEAR

The present invention relates to moulded footwear components and

to a method of manufacture for shoes and the like.

Shoes are commonly manufactured with soles and heels formed from

moulded plastics. In the interests of reducing both the weight and cost of

such shoes it is desirable to minimise the amount of material used to form

the sole and heel mouldings, whilst still providing adequate support for the

wearer's foot. To achieve this it is usual for sole and heel mouldings to

include hollow sections and/or lightweight space occupying inserts. In

some cases the hollow sections are filled with gas under pressure or a gel

to provide support and cushioning for the wearer's foot. Existing space

occupying inserts include foam materials and fabricated wedge like inserts.

Current fashions for shoes with chunky, platform, soles and heels

render the requirement to minimise the amount of plastic material used in

their construction particularly important.

It is an object of the present invention to provide an improved means

for producing the sole and heel construction of footwear.

According to one aspect of the present invention, there is provided

a moulded footwear component adapted to form an insert in an item of

footwear and comprising a moulded body having a plurality of internal strengthening ribs and a plurality of internal cavities in which the disposition

of the ribs and the cavities is chosen to provide different degrees of

resistance to pressure from different parts of the wearers foot.

According to another aspect of the present invention there is provided

a method of moulding by gas assisted injection moulding a moulded

footwear component comprising a body including the step of forming a

plurality of ribs and cavities in the body in a disposition to provide different

degrees of resistance to pressure from different parts of a wearer's foot.

In a preferred embodiment of the invention, the footwear component

may comprise a sole, a heel or a combined sole and heel. The component

is advantageously formed externally to provide means for keying an external

layer about the component moulded in a second moulding operation or fixed

to the component in some suitable other way. This external forming may

comprise ribs or other projections or grooves or other indentations. The

external layer is advantageously visually attractive and is shaped and/or

patterned to accord with current fashion requirements. Specifically, the

dimensions such as width or depth of the external layer, can be varied as

required. Furthermore, the material of the outer layer may be formed from

more expensive material than the insert in order to provide the required

degree of visual appeal. The same footwear component may therefore

provide the base for a larger variety of footwear differing substantially in external appearance. A series of footwear components of progressively

increasing or decreasing size may provide for footwear over the desired size

range or, as mentioned above, a variety of footwear differing as required in

external appearance. In practice, a different series of components would

be provided for men's footwear, women's footwear and children's

footwear. Possibly, additional series could be provided for specific special footwear types and each range of inner shoe components could be

produced in the required sizes or groups of sizes. The external layer may

be fitted around the said inner shoe component as a skin of variable

thickness to form the desired visual appearance and functionality of the

shoe. The inner shoe component may be placed in a larger mould cavity so

that plastic may be injected around the inner shoe component, thereby forming the outer shoe sole and/or heel. Alternatively, the inner shoe

component may be fitted after the external moulding has been made, and

fixed into cavities of matching shape and dimensions in the external

moulding by gluing or other fixing means. An inner sole of a single material,

or a combination of laminated material, may be fixed to the inner shoe

component by conventional means, either on a flat or configured moulded

surface of the inner shoe or fixed to the upper surfaces of the ribs and

hollow sections. A sub-assembly of an inner shoe component and an inner

sole may be placed in a larger mould cavity, enabling the outer and lower sole to be moulded around the sub-assembly. Additionally, there are well

established methods of moulding shoe upper coverings into position in a

mould when plastic is injected into the lower and outer sole cavities.

In order that the invention may be more clearly understood

embodiments thereof will now be described, by way of example, with reference to the accompanying drawings of which:-

Figure 1 shows a plan view of a combined sole and heel insert

according to the invention, fitted into an outer moulding with

a shaded footprint to show the position in use of a wearer's

foot, Figure 2 shows a longitudinal cross-sectional view of a combined sole and heel assembly including the insert of figure 1 , taken along

the line X-X of figure 1 ,

Figure 3 shows another plan view of the insert of figure 1 with the

location of the hollow regions of the insert shown in dashed

lines,

Figure 4 shows a cross-sectional view of the assembly of figure 3,

taken along the line Y-Y of figure 3.

Figures 5 to 8 show respectively transverse cross-sectional views through

the assembly shown in figure 2 taken along the lines E-E, F-F,

G-G and H-H of figure 2. Figures 9 to 12 show respectively similar view to figures 5 to 8, but where

the assembly has been deflected under the pressure exerted by

a wearers foot taken along the section line E-E, F-F, G-G and H-H of figure 4.

Figure 13 shows a plan view of another combined sole and heel insert according to the invention, fitted into an outer moulding with

a shaded footprint to show the position of a wearers foot,

Figures 14 to 17 show respectively transverse cross-sectional views

through a combined sole and heel assembly including the insert of

figure 13, taken along the lines l-l, J-J, K-K and L-L of figure 13.

Figure 18 shows a plan view of another combined sole and heel insert

according to the invention, fitted into an outer moulding with

a shaded footprint to show the position of a wearers foot,

Figures 19 to 23 shows respectively transverse cross-sectional views

through a combined sole and heel assembly including the insert

of figure 18, taken along the lines M-M, N-N, O-O and P-P of

figure 18.

Figures 24 to 27 show a number of cross-sections through sole and heel

assemblies including alternative embodiments of inserts

according to the invention.

Referring to figures 1 to 12, there are shown various views of a combined sole and heel assembly including a footwear component

comprising a combined sole and heel insert 1 in accordance with the

invention.

The same reference numerals are used throughout figures 1 to 12 to

indicate corresponding parts of the assembly.

The assembly comprises the insert 1 , an outer moulded layer 2 and

an inner sole 3 (not shown in figures 1 and 3). An upper (not shown) may

be attached to the assembly to form a complete shoe. Methods by which

an upper could be attached are well known and will therefore not be

described further.

The insert 1 is moulded by a gas assisted injection moulding process

in a single piece from a resilient synthetic plastic material. The insert

comprises a number of hollow, generally tubular, sections 4 joined by webs

5. The hollow section 4 have a generally rectangular outside cross-section

and occupy the space between the outer layer 2 and inner sole 3 to provide

support for the wearer's foot, whilst keeping the mass of the sole and heel

assembly down. Since the hollow sections 4 are joined by relatively thin

webs 5 the space between the hollow sections where there are no webs

form grooves 6. The outer layer 2 includes upstanding ribs 7 which

correspond to and cooperate with the groove on the underside of the insert

1 . The grooves 6 above the webs 5 are not filled, they allow the hollow sections to be deformed, allowing the insert 1 to more readily accommodate

a wearer's foot. Figure 9 to 12 show how, when depressed, the hollow

sections expand into the grooves.

The insert 1 is formed by gas assisted injection moulding, with gas

being used to core out the hollow sections 4. The insert could also include

mechanically cored out sections. The insert may be formed from any

suitable plastics material. Flexibility and rigidity can be varied by the

compounding of different material formulations, in order to match the

specific cushioning effect and strength of the inner shoe components.

The size and configuration of the hollow sections is arranged to

provide support for different areas of the wearer's foot which exert different

pressures. For instance the ball of the wearer's foot tends to exert a higher

pressure than, say, the instep. As can be seen in the drawing, particularly

the cross-sections taken along the line F-F a larger hollow section is

included in the region where the ball of the wearer's foot will bear, to give

greater cushioning.

The completed assembly is produced by placing the insert 1 into a

mould cavity and then injecting plastic into the cavity to mould the outer

layer 2 around the insert 1 . Alternatively the insert 1 could be fitted into

a ready moulded outer layer 2.

The inner sole 3 can then be affixed to the inner 1 and outer layer 2 combination. The innersole 3 may be formed from a single or multiple

layers of material, for example fibrous or foamed material.

Alternatively, the inner sole 3 could be affixed to the insert first and

this sub-assembly placed into a mould cavity for the outer layer 2 to be

moulded on. An upper could also be incorporated in this stage.

Figures 13 to 17 show another combined sole and heel assembly,

including an alternative embodiment of a combined sole and heel insert 21

fitted into an outer layer 22 and covered with an inner sole 26 (not shown

in figure 13).

In this embodiment, the insert 21 includes both a hollow section 24

and upstanding ribs 25. The hollow section 24 is contoured to match a

wearer's foot to provide resilient support in predetermined places.

Figures 18 to 23 show a further combined sole and heel assembly,

again including an alternative embodiment of a combined sole and heel

assembly 30, fitted into an outer layer 31 , and an inner sole 32 (not shown

in figure 18).

The insert 30 includes both hollow 33 and solid 34 thicker sections

and continuous and non-continuous ribs 35. The hollow sections 33 are

contoured to match the pressure areas of the wearer's foot, including the

toes, to provide resilient cushioning.

Figures 24 to 27 show a number of cross-sections through combined sole and heel assemblies, principally to show a number of different inserts

including hollow sections of different cross-section, for example, triangular

in figures 24 to 27, and hexagonal in figure 21 .

In the arrangement shown in figure 25 the outer combined sole and

heel moulding also includes hollow surface sections.

It will be appreciated that the above embodiment has been described

by way of example only and that many variations are possible without

departing from the scope of the invention. Although, particular examples

of cavities or hollows and of ribs and webs have been given, the size,

shape, type and distribution of the cavities/hollows and ribs/webs may be

altered as described to give the desired variation in cushioning and pressure

resistance over the whole area of the component and therefore over the

whole sole and heel area of the item of footwear of which the component

forms part. The invention therefore provides complete flexibility in the

provision of cushioning and pressure resistance both as to degree and

distribution over the normal footwear range subject to the provision of a

limited number of components. The addition of the outer layer enables these

characteristics to be provided in a wide range of visually appealing styles

whilst securing savings to the weight of and expenditure on materials used.

Claims

1. A moulded footwear component adapted to form an insert in an item

of footwear and comprising a moulded body having a plurality of internal strengthening ribs and a plurality of internal cavities in which the disposition

of the ribs and the cavities is chosen to provide different degrees of resistance to pressure from different parts of the wearers foot.

2. A moulded footwear component as claimed in claim 1 , in which

external formations are provided for keying the component to an external

layer.

3. A moulded footwear component as claimed in claim 2, in which the external formations comprise projections.

4. A moulded footwear component as claimed in claim 3, in which the projections comprise ribs.

5. A moulded footwear component as claimed in claim 2, 3 or 4, in

which the external formations comprise indentations.

6. A moulded footwear component as claimed in claim 5, in which the

indentations comprise grooves.

7. A moulded footwear component as claimed in any preceding claim,

in which an external layer is fitted around the component.

8. A moulded footwear component as claimed in claim 7, in which the

external layer is visually attractive.

9. A moulded footwear component as claimed in claim 7 or 8, which

forms a heel.

10. A moulded footwear component as claimed in claim 7 or 8, which

forms a sole.

1 1 . A moulded footwear component as claimed in claim 7 or 8, which

forms combined sole and heel.

12. A method of moulding by gas assisted injection moulding a moulded

footwear component comprising a body including the step of forming a

degrees of resistance to pressure from different parts of a wearer's foot.

13 A method of moulding as claimed in claim 12, in which the

component is formed externally to provide means for keying an external

layer about the component to the component.

14. A method of moulding as claimed in claim 1 3, in which the external

layer is moulded around the component in a second moulding operation.

15. A method of moulding as claimed in claim 13, in which the external

layer is fixed to the component.

16. A method of moulding as claimed in claim 13, in which the external

layer is moulded first with a cavity for the component and the component

is fitted into the cavity.

17. A method as claimed in claim 13, in which an inner sole is fixed to the component.