The invention relates to an item of footwear in which is provided a mid-sole with features that provide comfort to the wearer when walking.

It is known to provide grooves in the soles of footwear to increase the flexibility thereof. Such footwear is generally designed for sporting use and not for comfort. There is therefore a need to provide comfortable footwear designed for everyday usage. Accordingly, there is provided an item of footwear as defined by the appended claims.

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 drawings in which:

Figure 1 shows the underside of an item of footwear in accordance with the present invention;

Figure 2 shows a cross-sectional view through the mid-sole of the item of footwear of Figure 1 ; and

Figure 3 shows a schematic close-up cross-section of the item of footwear.

Figure 1 shows an embodiment of an item of footwear in accordance with the invention.

The item of footwear comprises a sole 1 . The sole 1 comprises a mid-sole 10. The mid-sole 10 comprises or is formed from: ethylene vinyl acetate (EVA) and/or expanded foam (such as biodegradable expanded foam).

An optional outsole 40 may be provided. The outsole 40 may comprise or be formed from: rubber. As can be seen from Figure 1 , the outsole 40 may be textured (in addition to the grooves described below) to provide additional grip.

The mid-sole has a first major surface 1 1 for facing the foot of a wearer and a second major surface 12 opposite the first 1 1 facing away from the foot of the wearer. The mid-sole 10 has an inner edge 13 corresponding to the inside of a wearer's foot and an outer edge 14 corresponding to the outside of a wearer's foot. The mid-sole 10 includes a forefoot region A arranged to support the forefoot of a wearer of the item of footwear. The forefoot region A extends over the forwardmost 15% to 24% of the length of the mid-sole 10. The mid-sole 10 includes an arch region B arranged to support the arch of the foot of a wearer of the item of footwear. The mid-sole 10 includes a heel region C arranged to support the heel of a wearer of the item of footwear. The heel region C extends over the rearmost 29% to 39% of the length of the mid-sole 10. The arch region B extends from the forefoot region A to the heel region C.

The item of footwear comprises a securing means (not shown) for securing the item of footwear to a foot of a wearer (for example, the securing means may be a strap such as in an open shoe, or an upper, if the item of footwear is a closed shoe). When in use the first major surface of the sole supports the user's foot. The first major surface of the midsole 10 can contact the user's foot directly or an insole can be interposed between the midsole 10 and the user's foot. The term midsole used in the specification should be understood to refer to a component which is: sandwiched between an insole and an outsole, or contacts the user's foot directly and is provided with an outsole; or is used in a shoe without an insole or outside and provides itself the contact surface for a user's foot and the ground.

A plurality of generally transverse grooves 20 are formed in the mid-sole 10. The transverse direction extends from the inside edge 13 to the outside edge 14, perpendicular to the longitudinal direction of the item of footwear. Preferably, the plurality of generally transverse grooves 20 each extend from the inside edge 13 to the outside edge 14.

The plurality of generally transverse grooves 20 are preferably substantially arc-shaped. That is, the transverse grooves 20 are curved such that their midpoints are further forward on the midsole 10 than their outermost extents.

The radius of curvature of the plurality of generally transverse grooves 20 increases with increasing distance from the rearmost point of the mid-sole 10. In this way, the transverse grooves 20 near the heel of the item of footwear have a smaller radius of curvature (they are more curved) than the transverse grooves 20 near the frontal end of the item of footwear.

Each of the plurality of generally transverse grooves 20 is spaced from its nearest neighbour by a distance in the range 8mm to 14mm. The mid-sole 10 comprises a generally longitudinal primary groove 30a. The generally longitudinal primary groove 30a extends over at least 50% of the length of the midsole 10 in the longitudinal direction X, and preferably at least 70%. The longitudinal direction X extends from the rearmost point of the heel of the item of footwear to the forwardmost point. At least a forward portion of the primary groove 3a is a arcuate in form when viewed in a plan view, as seen in Figure 1 .

More preferably, the mid-sole 10 comprises a second generally longitudinal groove 30b. The second generally longitudinal groove 30b extends in the longitudinal direction through at least 50% of the forefoot region, the secondary groove being substantially parallel with the primary groove. The second groove 30b is arcuate in form when viewed in a plan view, as seen in Figure 1 . Most preferably, only the two longitudinal grooves 30a, 30b are provided.

The primary and secondary grooves may be spaced apart by a distance in the range 25mm to 40mm.

The depths of the transverse grooves are preferably in the range 7mm to 12mm.

The depths of the longitudinal grooves are preferably in the range 10mm to 12mm.

The thickness of the mid-sole 10 has a general taper such that the heel region C has a greater depth than the forefoot region A. Optionally, the depths of the grooves 20, 30a, 35, 36 may be greater in the heel region C. For example, the depths of the grooves 20, 30a, 35, 36 in the heel region C may be in the range 7mm to 12mm, with the grooves 20, 30a, 30b in the forefoot region A and arch region B having a depth in the range 5mm to 10mm.

Together, the longitudinal and transverse grooves 20, 30a, 30b dividing the sole into an array of lands 50. As can be seen from Figure 2, the lands 50 are regions of the mid-sole 10 that are formed integrally with an uninterrupted substrate layer 70 of the mid-sole 10. The uninterrupted substrate layer 70 is shown by line Y in Figure 2. The uninterrupted substrate layer 70 of the mid-sole 10 has a minimum thickness of 5mm. The uninterrupted substrate layer 70 is flexible and so forms a hinge allowing a degree of relative movement between the lands 50. In use of the item of footwear, this flexibility allows the mid-sole 10 to deform with the foot of the user. The inventor has discovered that the curvature of the grooves 20, 30a, 30b can be designed to achieve an improvement in the comfort of the wearer. Specifically, it is preferable if the primary longitudinal groove 30a is shaped to follow the path of maximum contact between a wearer's foot and the ground. A normal step commences with impact of the heel with the ground. As the foot rolls from the heel to the toes, the point of greatest contact with the ground travels along the outside of the foot.

It has been found that configuring the primary longitudinal groove 30a to follow the outer edge 14 of the mid-sole 10 provides improved comfort. In this way, the lands 50 forming a row along the outer edge 14 have substantially equal width. Preferably, the lands 50 forming a row along the outer edge 14 have a width (in the transverse direction) in the range 20mm to 30mm.

The shape of the mid-sole 10 is of a typical shape in plan view, with the edges 13, 14 being generally parallel in the heel region C. Therefore, the primary groove 30a extends generally centrally through at least a portion the heel region C such that the mid-sole 10 is divided into two longitudinal rows of lands 50, with each row 50 having substantially the same width in the transverse direction.

The secondary groove 30b begins/terminates at or near the inner edge 13 of the mid-sole 10 in the arch region B. Between the secondary groove 30b and the outside edge 14, the mid-sole 10 is divided into two longitudinal rows of lands 50, with each row 50 having substantially the same width in the transverse direction. Between the secondary groove 30b and the inside edge 13, the mid-sole 10 includes a single row of lands 50 that preferably increase in width in the transverse direction from the arch region B towards the portion of the mid-sole 10 corresponding to ball of the wearer's foot.

Whilst it is possible for the primary longitudinal groove 30a to terminate at the rearmost point of the mid-sole 10, it is preferable that the primary longitudinal groove 30a terminates in the heel region C. In such an embodiment, the heel region C of the mid-sole 10 comprises a central land 52 located generally centrally in the transverse direction. The central land 52 receives the primary impact during the heel strike. The central land 52 is preferably surrounded around its entire perimeter by a plurality of surrounding lands 53. The central land 52 is preferably circular, when viewed in a plan view as in Figure 1 ,and the surrounding lands 53 are preferably arc-shaped, being separated by groove 36 which extend radially outwardly from the land 52, when viewed in plan view, as in Figure 1 . The central land 52 may have a radius of approximately 15mm.

The central land 52 is surrounded by a groove 35, which may meet the primary groove 30a, and separates the central land 52 from the arc-shaped lands 53. The radially extending grooves 36 extend outwardly from the groove 35 to separate the neighbouring arc-shaped lands 53.

Since the central land 52 is subject to large forces, an insert (e.g. a rigid insert) is provided in the central land. Similarly, inserts 103 may be provided in one or more of the arc-shaped lands 53. The inserts 102, 103 may be formed of or comprise rubber.

The mid-sole 10 includes a fowardmost region 54 within the forefoot region A. Preferably, the transverse and longitudinal grooves 20, 30a, 30b do not extend into the forwardmost region 54. This region is where the wearer pushes off in the latter part of each step and so it is preferable to provide an insert 101 is provided in the forwardmost region 54. The insert 101 may be formed of or comprise rubber. Preferably, the insert 101 is textured to provide grip.

The forwardmost region 54 may, for example, extend over the forwardmost 20% of the length of the mid-sole 10 in the longitudinal direction.

As can be seen in Figure 2, the transverse and longitudinal grooves 20, 30a, 30b have a generally tapered cross-section (perpendicular to their lengths) such that the grooves 20, 30a, 30b are wider when they meet the second major surface 12 than at their deepest points. The width of the openings of the grooves 20, 30a, 30b at the second major surface 12 is in the range 1 mm to 3mm.

As mentioned above, the item of footwear preferably does not comprise an outsole 40. An outsole 40 could be provided. This would be a layer formed of or comprising rubber. As shown in Figure 3, the outsole 40 could cover the mid-sole 10 such that it extends within each groove 20, 30a, 30b, 35, 36 but does not entirely fill the groove. In other words, the outsole 40 is wrapped around the lands 50, 52, 53 of the mid-sole 10.