The following describes a method of manufacturing an item of footwear and an item of footwear made according to that method of manufacture.

It is known to manufacture items of footwear with multiple layers. However, to do so requires the application of an adhesive between the facing surfaces of the layers. Such an adhesive can alter the behaviour of the materials to which it is adhered. In some cases, it can also be felt by the foot of the user.

According to the invention, there is provided an item of footwear and a method of manufacturing an item of footwear as defined by the appended claims.

A method of manufacturing an item of footwear is provided, the method comprising:

forming a lower sole member comprising a floor and a wall around the perimeter of the floor, the floor and the wall together defining a cavity; forming an insert, the insert having an edge with a complementary shape to the wall such that the insert is sized and shaped such that at least a portion of the insert is complementary to the cavity; and adhering the edge of the insert to the wall of the lower sole member.

Preferably, the insert directly contacts the floor of the lower sole member.

The lower sole member may comprise first and second major surfaces, the first major surface defining the floor and the second major surface opposite the floor and arranged to contact the ground in use.

The wall may be continuous around the entire perimeter of the floor.

Adhering the edge of the insert to the wall of the lower sole member may comprise applying adhesive to the edge of the insert and/or to the wall of the lower sole member and then inserting the insert into the cavity.

The method may not include a step of applying adhesive to the centre of the floor. The step of forming a lower sole member may comprise: providing a quantity of a first material; and expanding the first material within a first mould to thereby form the floor and the wall. The step of forming an insert may comprise: providing a quantity of a second material; and expanding the second material within a second mould to thereby size and shape the insert such that at a least part thereof is complementary to the cavity.

The lower sole member and the insert may be formed of the same material.

The step of forming an insert may comprise: providing a quantity of a second material; expanding the second material within a second mould to thereby form an upper sole member; providing a third material for forming a shoe upper; and wrapping the third material around at least a portion of an edge of the upper sole member to form the insert.

The lower sole member and the upper sole member may be formed of the same material.

An item of footwear is provided, the item of footwear comprising: a sole; securing means for securing the sole to the foot of a wearer; an insert arranged for contacting the foot of a wearer of the item of footwear; and a lower sole member arranged for contacting the floor, wherein: the lower sole member comprises a floor and a wall around the perimeter of the floor, the floor and the wall defining a cavity in which the insert is inserted; the insert is adhered to the wall of the lower sole member by an adhesive. Preferably, the insert directly contacts the floor of the lower sole member.

The lower sole member may comprise first and second major surfaces, the first major surface defining the floor and the second major surface opposite the floor and arranged to contact the ground in use.

The wall may be continuous around the entire perimeter of the floor. The adhesive may form a border around the perimeter of the floor. A central region of contact between the insert and the floor may be substantially free of adhesive.

A central region of contact between the insert and the floor may be entirely free of adhesive.

The insert may be not adhered to the centre of the floor of the cavity. The insert may contact the floor without a layer of adhesive therebetween.

The insert may be not adhered to the floor of the cavity.

The wall may have a height and a width in which; the height of the wall is the distance by which it protrudes from the floor; the height is in the range 5mm to 8mm.

The wall may have a height and a width in which; the height of the wall is the distance by which it protrudes from the floor; the width is in the range 3mm to 7mm.

The insert may have a width of least 80% of the width of the lower sole member.

The insert may have a length of least 90% of the length of the lower sole member.

The insert may comprise a moulded upper sole member sized and shaped such that at least a portion thereof is complementary to the cavity.

The insert may comprise a moulded upper sole member and a shoe upper wrapped around the moulded upper sole member, and the insert may be sized and shaped such that it has an edge that is complementary to the cavity. The upper sole member may be arranged for contacting the foot of a wearer of the item of footwear in all of the frontal, arch and heel regions.

The upper sole member may have a substantially constant thickness in the frontal and arch regions. The upper sole member may comprise a laterally-central bulge in the heel region. The upper sole member may comprise an annular bulge surrounding the central bulge. The upper sole member may extend from the floor beyond the wall The floor of the cavity may be laterally concave.

The inventor has discovered that a more comfortable item of footwear with multiple layers may be manufactured by adjoining a first layer to a second via a wall extending from the perimeter of the first layer. The adhesive can be applied to the wall rather than the area below the wearer's foot. The inventor has further realised that such an absence of adhesive between two layers of sole can advantageously alter the behaviours of the sole under flexure. Specifically, the bending of the unconnected layers of the sole provides a different distribution of stresses within the sole than would be exhibited by a unitary body (or a body formed of two parts adhered together). Ultimately, this has been found to lead to greater comfort for the wearer.

For a better understanding of the invention and to show how the same may be put into effect, reference will now be made, by way of example only, to the accompanying drawing in which:

Figure 1 shows a cross-section of a sole forming part of an embodiment of the invention; Figure 2 shows an item of footwear in the form of an open shoe having the sole of Figure 1 ; and

Figure 3 shows an item of footwear in the form of a closed shoe having the sole of Figure 1 .

An embodiment of an item of footwear in accordance with the invention comprises a sole 10 and securing means 15 for securing the item of footwear to the foot of a wearer.

The item of footwear defines a longitudinal direction (the longest distance from the heel to the toe) and a lateral direction (perpendicular to the longitudinal direction).

The sole 10 comprises a lower sole member 100 and an upper sole member 200. The securing means 15 may be formed as a strap or shoe upper to thereby define an open or closed shoe, respectively. The securing means 15 extends from the item of footwear in a direction corresponding to the upward vertical direction when the item of footwear is worn by a wearer standing on flat and level ground.

In the case of a closed shoe, the securing means 15 (in the form of a shoe upper) and the upper sole member 200 collectively form an insert 300. In the case of an open shoe, the upper sole member 200 may form an insert 300 with or without the securing means 15. As can be seen from Figure 3, in a closed shoe, the material forming the shoe upper is wrapped around the edge of the upper sole member 200 and adhered thereto. It is preferred that the adhesive is only intentionally applied to the edge of the upper sole member 200. In order to ensure a strong attachment, it may be necessary to wrap some of the material around to overlap at least some of the underside 210 of the upper sole member 200 and adhere it to the underside 210. Preferably, however, the shoe upper will merely be wrapped around the edge of the underside 210. In the embodiment shown in Figure 3, the shoe upper 15 forms an enclosure into which the upper sole member 200 is inserted. In this example, the shoe upper 15 completely separates the upper sole member 200 from the lower sole member 100.

The lower sole member 100 may be a unitary body having at least one layer 101 . The at least one layer 101 has two major surfaces. A first of the major surfaces of the at least one layer 101 defines a floor 1 10. The second major surface 130, opposite the floor 1 10, may be arranged to contact the ground in use, or to contact a further layer (or layers) for engaging the ground in use.

A wall 120 extends from the at least one layer 101 along the perimeter of the floor 1 10. Preferably, the wall 120 is continuous around the entire perimeter of the floor 1 10. The wall 120 has a height and a width. The height of the wall 120 is the distance by which it protrudes from the floor 1 10. The width of the wall 120 is the maximum dimension of the wall 120 measured perpendicular to its height (i.e. measured in a plane parallel to that including the longitudinal and the lateral directions of the item of footwear as a whole). The width of the wall 120 is in the range 3mm to 7mm. The height of the wall 120 is in the range 5mm to 8mm. The second of the major surfaces 130 of the layer 101 may define a ground contacting surface. In some embodiments, a second layer may be provided on the second major 130 surface of layer 101 for contacting the ground (e.g., an outsole may be provided).

The floor 1 10 and the wall 120 together define a cavity into which the insert 300 is inserted. The wall 120 has an inner surface 125 that faces inwardly with respect to the cavity.

The upper sole member 200 is arranged for contacting the foot of a wearer of the item of footwear. Preferably, the upper sole member 200 is arranged for contacting the foot of a wearer of the item of footwear in each of the frontal 4, arch 5 and heel 6 regions.

Optionally, the upper sole member 200 may comprise multiple layers.

It is intended that the upper sole member 200, rather than the lower sole member 100, supports the foot of the wearer. Therefore, it is preferable that the upper sole member 200 has a width of least 80% of the width of the lower sole member 100. Preferably, the upper sole member 200 also has a length of least 90% of the length of the lower sole member 100. As can be seen from Figure 1 , the upper sole member 200 is preferably tapered so as to have a wider first major surface 230 (the upper surface) than second major surface 210 (the lower surface), so that the wearer's foot will not feel the wall 120. In addition, the wall may be angled outwardly, corresponding to the taper of the upper sole member 200.

The insert 300 is sized and shaped to be substantially complementary to the cavity in the lower sole member 100. That is, a portion of the insert 300 has a portion substantially matching the size and shape of the cavity. Optionally, the upper sole member 200 may either be substantially (or exactly) flush with, or extend above (as in Figure 1 ), the height of the wall 120.

In the case of a closed shoe, the insert 300 may be formed from a shoe upper 15 wrapped around the edge of the upper sole member 200. For such an insert 300 to substantially match in size and shape in plan view the complementary cavity in the lower sole member 100, the upper sole member 200 may be sized and shaped to leave a gap around its circumference between it and the wall 120. The gap may have a width of between 0.6mm and 2mm to correspond with the thickness of material from which the shoe upper is formed. The insert is preferably affixed within the cavity by an adhesive applied between the insert 300 and the wall of the lower sole member 100. Preferably, however, the insert 300 directly contacts the floor 1 10. When the insert 300 is affixed to the wall 120, the insert 300 is in contact with the floor 1 10 such that a major surface (lower surface) 210 of the insert is directly contacting the floor 1 10. The insert 300 may therefore contact the floor 1 10 both when there is a foot of a wearer applying a pressure on an upper major surface (230) and when there is no pressure applied.

The upper sole member 200 has an edge extending between the first and second major surfaces 210, 230. In the case of an open shoe, the edge of the upper sole member 200 may form the edge 225 of the insert 300. In the case of a closed shoe, the edge 225 of the insert 300 may be formed by the wrapped edge of the upper sole member 200.

The edge 225 of the insert 300 is adhered to the inner surface 125 of the wall 120 of the lower sole member 100.

Ideally, there would not be a layer of adhesive between the floor 1 10 and the insert 300. In other words, a major surface (a lower surface) 210 of the insert 300 would preferably directly contact the floor 1 10 over its full area.

In the case of a closed shoe having a shoe upper 15 that separates the lower sole member 100 from the upper sole member 200, it is also preferred that there would not be a layer of adhesive between the lower sole member 200 and the shoe upper 15. In other words, a major surface (a lower surface) 210 of the upper sole member 200 would preferably directly contact the inside of the shoe upper 15 over its full area. The adhesive is preferably only intentionally applied to the edge of the upper sole member 200.

In practice, it is possible that some adhesive for adhering the edge 225 to the inner surface 125 could inadvertently flow into the region between the floor 1 10 and the facing surface of the insert 300. However, this would be only minor. In such an embodiment, it is preferable that a central region of contact between the facing surface of the insert 300 and the floor 1 10 is substantially free of adhesive, and preferably entirely free of adhesive. It is preferable that the central region of contact comprises at least 50% of the total area of the facing surface, and more preferably at least 75%. For example, there may be a border around the floor 1 10 in which there may be some adhesive. This is preferably minimised such that no more than 10%, and preferably no more than 5%, of the width of the floor 1 10 below the ball of the foot or in the arch region carries any adhesive.

In the case of a closed shoe having a shoe upper 15 that separates the lower sole member 100 from the upper sole member 200, it is preferred that the central region of contact adhesive between the lower sole member 200 and the shoe upper 15 comprises at least 50% of the total area of the facing surfaces, and more preferably at least 75%.

Any border formed by adhesive between the lower sole member 200 and the shoe upper 15 is preferably minimised such that no more than 10%, and preferably no more than 5%, of the width of the lower sole member 200 below the ball of the foot or in the arch region carries any adhesive.

The upper sole member 200 preferably has a substantially constant thickness

perpendicular to its major surfaces. However, the upper sole member 200 may optionally comprise a protrusion 250 in the heel region 6. The protrusion 250 may be located centrally in the lateral direction. When the protrusion 250 is provided, it is preferred that the upper sole member 200 has a substantially constant thickness in the frontal region 4 and in the arch 5 region.

A preferred form of protrusion 250 comprises a central bulge 252 surrounded by an annular bulge 254. The central bulge 252 is preferably dome-shaped, most preferably with a circular edge. The thickness of the insert through the central bulge 252 is preferably greater than the thickness of the insert through the annular bulge 254.

Preferably, the floor 1 10 of the cavity is laterally concave, and the upper sole member 200 is flexible and so conforms to the shape of the floor 1 10. In this way, despite the

substantially constant thickness of the upper sole member 200 (apart from the protrusion 250), the upper surface of the upper sole member 200 is thus also laterally concave when in place within the cavity. An embodiment of a method in accordance with the invention for manufacturing an item of footwear such as that described above, comprises: forming a lower sole member 100 with a cavity; forming an insert 300; and inserting the insert 300 into the cavity of the lower sole member 100.

As described above, the lower sole member 100 comprises a cavity defined by a floor 1 10 and a wall 120 around the perimeter of the floor 1 10. The insert 300 is arranged for contacting the foot of a wearer of the item of footwear, and is sized and shaped to have an edge 225 that is complementary to the cavity.

The method comprises the step of adhering the edge 225 of the insert 300 to the inwardly facing inner surface 125 of the walls 120 of the lower sole member 100. Preferably, this involves applying an adhesive to one or both of the edge 225 and inwardly facing inner surface 125 before inserting the insert 300 into the cavity of the lower sole member 100.

As would be apparent from the description above, in order to avoid having a layer of adhesive between the lower surface 210 of the insert 300 and the floor 1 10 of the lower sole member 100 or at least minimise the adhesive therebetween, the method preferably does not include a step of deliberately applying adhesive to the floor 1 10 of the lower sole member 100 or the lower surface 210 of the insert 300.

Whilst it is possible that some adhesive may inadvertently arrive on the floor 1 10, this would be unintentional and would only affect a region around the perimeter of the floor 1 10. Accordingly, the method preferably does not include a step of applying any adhesive to the centre (e.g., the geometric centre or centroid) of the floor 1 10 of the lower sole member 100.

Indeed, in such an example, it is the case that the adhesive would not have been applied to the floor 1 10 or the major surface 210 (the lower surface that contacts the floor 1 10) of the insert 300 prior to insertion into the cavity because it would be the act of insertion that inadvertently spreads or squeezes the adhesive between the floor 1 10 and the insert 300.

The lower sole member 100 and the insert 200 are formed separately. The lower sole member 100 may be formed by a method in which a quantity of a first material is expanded within a first mould to thereby form the lower sole member 100 into a shape having both the floor 1 10 and the wall 120. The upper sole member 200 may be formed by a method in which a quantity of a second material is expanded within a second mould.

In the case of an open shoe, the upper sole member 200 may be formed by a method in which a quantity of a second material is expanded within a second mould to thereby size and shape the insert 200 to have a portion with an edge 225 that is complementary to the cavity defined by the floor 1 10 and the wall 120.

In the case of a closed shoe, the upper sole member 200 may be formed by a method in which a quantity of a second material is expanded within a second mould to thereby size and shape the upper sole member 200 for leaving a gap around its circumference between an edge of the upper sole member 200 and the wall 120. The gap may have a width of between 0.6mm and 2mm to correspond with the thickness of material from which the shoe upper 15 is formed. Thus, the insert 300 will have a portion for insertion into the cavity having an edge 225 that is complementary to the cavity defined by the floor 1 10 and the wall 120.

The insert 300 is formed by attaching the shoe upper to the upper sole member using an adhesive. The shoe upper 15 preferably extends at least as far as the second major surface 210 of the upper sole member 200. In some cases, the shoe upper wraps around to contact the second major surface 210 of the upper sole member 200. In some embodiments, the shoe upper 15 does not extend into the central region of contact and so the central region of contact is between the upper sole member 200 and the floor 1 10. In embodiments of the type shown in Figure 3, the shoe upper 15 extends around the central region of contact and so the central region of contact is between the shoe upper 15 and the floor 1 10.

Adhesive is applied to the inner surface 125 of the wall 120 and/or the edge 225 of the insert 300. The insert 300 is then inserted within the cavity such that the edge 225 adheres to the wall 120.

Preferably, although not essential, the first and second materials are the same material. Preferably, that material is an elastomeric polymer such as ethylene-vinyl acetate (EVA) and more preferably, high rebound EVA. Alternatively, the material may be polyurethane.