The present invention relates to an article on footwear, particularly but not exclusively, a ski boot.

In certain activities, such as skiing, it is necessary for the participant to wear footwear which gives support to the ankle, particularly lateral support, to prevent injury caused by lateral forces or twisting and turning forces. Conventional ski boots address this problem by providing a substantially rigid plastics casing which encases the foot, the ankle joint and the lower part of the leg above the ankle joint. To provide a degree of comfort a liner providing a degree of resilience and padding is inserted in the plastics casing. Such boots provide the necessary support to the ankle joint but have a number of disadvantages both from a wearer's perspective and from a manufacturer's perspective.

For the wearer, the conventional boots have a number of disadvantages. Primarily, because they are rigid and closed, it is extremely difficult to get a comfortable fit whilst also providing control over the ski. Furthermore, because they are formed of a non- breathable closed plastics material the wearer's feet get soaked in sweat which leads to discomfort and also can lead to blistering and fungal infections. The boot also has small expansion gaps at the front, which tend to let in snow and water, exacerbating the wetness caused by sweating feet. After being worn, it is also difficult to dry the liner in the boot, which absorbs sweat from the wearer, in view of the closed in nature of the boot. It is possible but cumbersome to remove the liner each day or to buy special boot driers, but these are relatively expensive.

Partly because of this environment, the liners have a limited life and need to be replaced on a regular basis to avoid a worsened fit and discomfort, which involves a significant expense. A further significant disadvantage of the known boot is that its stiffness varies greatly with temperature. When very cold it is uncomfortably stiff, but as the boot warms up due to rising ambient temperature and/or heat from the sun, the plastics material softens which greatly reduces the stiffness and hence the support that it gives. Another disadvantage of the known boot is that they are extremely heavy, typically weighing 3-5 kg per pair. This makes skiing, walking and climbing in the boots harder, especially for wearers who are not extremely fit. Due to the stiffness of the boots and the facts that the wearer's ankle is effectively immobilised and the boot is longer and stiffer than conventional footwear it is also difficult to walk in the ski boots, to and from ski lifts for example.

From the manufacturer's perspective such boots have the disadvantage that they must be manufactured in half sizes to offer any prospect of a reasonable fit for the wearer. This has a number of disadvantages, in particular the fact that tooling and moulds must be provided for each half size, which greatly increases the manufacturing costs. In addition, extra costs are incurred in the stocking of ski boots in retail outlets, since every half size must be stocked or arrangements need to be set up with wholesalers to supply particular sizes as a matter of urgency when they prove to be required. This, again, increases costs.

The present invention seeks to provide a boot which reduces or eliminates the disadvantages of the known boot.

According to the present invention there is provided an article of footwear including: a substantially rigid sole part, substantially rigid lateral side supports extending upwardly from said sole part so as to provide lateral support to the leg of the wearer, a heel supporting element to locate the rear of the heel of a wearer, first strap means to secure the foot to the sole, and second strap means to secure the leg to the side supports adjacent the upper end thereof.

Preferably, the side supports are integrally formed with the sole part and may be substantially open at the rear and/or substantially open at the front to facilitate longitudinal movement of the leg relative to the foot by extension and flexion about the ankle joint.

Preferably, a stiffening web extends between the front edges of the side supports intermediate their height. A heel piece, which may be integral with the side supports, may extend upwardly from the rear of the sole and be conjoined with the side supports at a predetermined distance above the support surface of the sole to form a transverse stiffening web. Said first strap means includes a forward strap adapted to secure the front part of a foot to the sole and may have an adjustable fastening to enable the transverse width of the strap to be varied to accommodate different widths and/or heights of foot. The adjustable fastening preferably comprises a retaining element movable in a transversely extending slot in the sole. The first strap means preferably also includes a rear strap, which may be pivotally secured to the side supports, adapted to locate and restrain the rear part of the foot of a wearer and may include a heel support section and a foot restraining part.

The second strap means is preferably pivotally secured to the side supports adjacent the upper end thereof and preferably includes a fixed length loop extending between the upper ends of the side supports and being pivotally connected thereto, against which the shin of a wearer abuts in use. The fixed length loop is preferably resilient to provide longitudinal flexure for the leg of a wearer. Preferably, the loop is readily detachable to facilitate the fitting of a selected loop of differing length and/or degree of elasticity.

Preferably, the strap means have quick release fastenings, and. the length of the straps, which preferably include padding to protect the foot, may be adjustable.

Preferably, the lateral width between a mounting support for the rear strap secured to one side support and the opposite side support is adjustable to accommodate different widths of foot. In a preferred embodiment for the adjustment of the lateral width, the mounting support includes two contiguous ramped or stepped elements having opposing relatively movable ramped or stepped surfaces, one of said elements being secured to the support side and the other being secured to an inner strap end, said relative movement causing the element adjacent the foot to move laterally to alter the width between the said strap end and the opposing side support to accommodate different widths and shapes of foot, but without applying transverse pressure on the wearer's foot.

In a preferred embodiment, the sole and side supports are of one-piece construction, and may be formed of aluminium alloy, magnesium alloy, or a reinforced plastics material which may be reinforced with carbon fibres or a carbon fibre mesh, aramid fibres or glass fibres. Preferably, the cant of the boot is adjustable by means of adding spacer means to one of the inner sides of the side supports, but could also be adjustable by changing heel and toe pieces.

Preferably, the article of footwear includes a flexible cover adapted to resiliently engage a peripheral rim of the article of footwear so as to enclose the foot during use. The cover is preferably waterproof and gas permeable ("breathable").

A preferred embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which:-

Figure 1 is a front perspective view of a ski boot, Figure 2 is a rear perspective view, Figure 3 is a schematic plan view of a heel part of the boot, Figures 4a and 4b show an adjustable mounting for a foot strap, and Figure 5 shows a cover for the ski boot.

Referring now to Figures 1 and 2 in particular, there is shown a main structure or frame 1 for a ski boot which consists essentially of a sole part 2 and upstanding side supports 3 which extend upwardly to encompass the ankle joint and the sides of the lower part of the leg of a wearer. At the heel part of the boot the frame has a transverse web 4 extending round the heel and extending upwardly a short distance from the sole part 2 to provide a degree of stiffness to the side supports 3 but leaving the rear open substantially throughout its height. The side supports also each include a front extension 5, 6 which cover the sides of the foot and provide a degree of protection from blows from the side. The extensions 5, 6 also provide increased stiffness in the longitudinal direction of the sole 2. Although not essential, in this embodiment a transverse stiffening web 7 joins the upper edges of the front extensions 5, 6 intermediate their length so as to lie over the foot of a wearer. A further transverse stiffening web 8 joins the leading edges of the upstanding side supports 3 to increase the stiffness of the upstanding parts and to provide some physical protection to the front of the leg. In this embodiment, the structure is formed of aluminium and preferably is formed from a single sheet of aluminium shaped by pressing. In this embodiment, the transverse webs 7, 8 at the front of the boot and the transverse heel part 4 are formed by overlapping parts of the aluminium sheet which are then secured together by bonding or riveting or similar known technique. Alternatively, the two parts of the folded up sheet could be arranged to abut each other to be welded together. Although not shown, the front and rear edges 9, 10 of the upstanding parts may be folded in to increase the thickness at these parts to increase stiffness. It is also possible for the side parts 3 to have swages or corrugations extending along their length to increase the stiffness. Likewise flanged holes may be formed in the structure to increase stiffness and reduce weight. It is also envisaged that the sole part may be shaped during the forming operation to the form of a foot for greater comfort and to provide support for the instep. The sole is open at the front 11 to facilitate the accommodation of different sizes of feet.

The boot contains three straps 12, 13 14 to secure the foot and lower part of the leg in the boot. The straps 12, 13, 14 each consist of two strap parts 15, 16 joined together by a known type of fastening 17 having a rack 18 on one strap part end 15 which engages in a fastening element 19 on the other strap part 16. The fastening element 19 has a latch 20 engageable in the rack 18 under a resilient bias and a further lever 21 resiliently biased out of engagement with the rack 18 but pivotable manually into contact with the rack, further pivotable movement then causing the rack 18 to be drawn through the fastening element to tighten the strap, the strap being held in the tightened position by means of the latch 20. The latch 20 has a manually operable release arm operable to release the fastening by pivoting the said latch 20 out of contact with the rack 18

The first strap 12 is located so as to fasten over the foot in the region of the ball of the foot. One strap part 15 is secured to one of the side extensions 5 by means of a rivet or bolt which allows some pivotable movement of the strap 15 relative to the main frame 1. As shown particularly in Figures 4a and 4b, the other strap part 16 has an adjustable mounting in the sole part of the structure designed to enable the lateral position of the strap 16 to be adjusted automatically to the size of the foot as the strap is fastened. To this end, the mounting includes a transverse elongate slot 22 in the sole part 2 of the structure through which a T-shaped element 23 connected to the end of the strap 16 projects. The crossbar 24 of the T serves to prevent the T-shaped element 23 being pulled through the slot 22. The crossbar 24 is located in a recess 25 in an outer sole part 26 of the boot which is secured to the main frame 1. Other forms of slot or runner may be provided to give the lateral adjustment required. As can be seen particularly in Figure 1, padding 27 for the foot is located along the inner edges of the side extension and on the strap parts themselves, reference 28. When firmly fastened, the ball of the foot is thus held down onto the sole 2 and is also supported against lateral movement relative to the sole 2.

A second strapl3 is located so as to fasten across the instep of the foot to clamp the heel of a wearer firmly in position. In addition to the two strap parts 15, 16 described with reference to the front strap, the second strap 13 includes a heel loop 29 designed to locate the heel and, as the strap is fastened, to push the foot firmly against the heel loop 29. The heel loop may be an integral part of the strap but, alternatively, may be a separate loop pivotally connected to the pivotal connections 30, 31 of the two strap partsl5, 16. As shown particularly in Figure 2 and in the schematic plan view of Figure 3, one strap end is mounted directly on the main structure by means of a rivet or bolt 30 so as to pivot to accommodate variations in the size, particularly height, of the foot of wearer whilst the mounting of the other strap 15 is also pivotally mounted in the main frame 1 but includes an adjustable mounting 32 by which the transverse distance between the strap mountings is adjustable to accommodate different widths of foot.. To this end, the mounting 32 includes a stepped ramp arrangement consisting of a first ramp part 33 pivotally connected by a pin 31 to the main frame 1 so as to be pivotable relative to the frame, and a second ramp part 34 abutting the main structure and secured to the strap end 15, which second ramp part 34 is slidable relative to the first ramp part 33. To achieve this, the second ramp part 34 includes an elongate slot 35 through which the fastening pin 31 passes, thus locating the second ramp part 34 relative to the first part 33 but enabling it to move relative to the first part. Each ramp part 33, 34 includes two stepped sections 36 engageable with corresponding matching step sections on the other part. Each step has a lateral face 36a abutting a corresponding lateral face 36b of a step on the other ramp part. The risers 36c of each step are inclined at an angle α of around but rather less than 45° to a transverse axis. In operation, as the strap end 15 is pulled in the direction of the arrow (Figure 3) to fasten the strap, the first ramp part 33 is moved transversely until it contacts the heel when the extra resistance prevents the ramp part sliding up the angled risers 36c onto the next step during continued tightening of the strap. In this way, the strap securely clamps the heel part of the wearer's foot in the transverse direction but without applying an excessive transverse force to it. As in the previous embodiment, padding is provided to enhance the comfort of the wearer.

A third fastening strap 14 is located adjacent the upper ends of the side supports 3 and is pivotally connected to the supports 3. A forward fixed loop 37 against which the shin of a wearer rests is also pivotally connected to the side supports and which cooperates with the straps 15, 16 of a fastening arrangement as described for the previous straps 12, 13, located at the rear so that a person's leg can be strapped securely and firmly to the boot whilst skiing. The strap 14 and loop 37 include padding 38, whilst further padding forming a spacer between the support and the leg of a wearer may be provided on the inner surfaces of the side supports 3 and in this way the cant angle can be adjusted. The forward fixed loop 37, which may be integral with the remaining parts of the strap 14, has a degree of elasticity and padding to provide the normal degree of longitudinal flexing required whilst skiing. The length of the loop may be adjustable to provide alternative amounts of forward lean, whilst alternatively, the loop may be readily detachable and a selection of loops having different degrees of elasticity or length may be provided. When the wearer needs to walk, this fastening strap can be instantly released thus enabling the person's leg to move relative to the frame of the ski boot. This enables the ankle to extend and flex to facilitate walking in a relatively comfortable manner.

Turning now to Figure 5 there is shown a cover 39 for the ski boot which consists of a plastics or fabric material which is preferably waterproof but gas permeable ("breathable"), so as to allow water vapour to pass through. The material sold under the Registered Trademark GORE-TEX is a suitable material. The cover may consist of several layers of material such as an outer plastics material such as nylon, with a waterproof and gas permeable lining with, in addition, an inner insulating layer. As shown, the cover includes a zip 40 which can be opened to adjust the straps or ventilate the interior. Although the zip position is shown on the top of the foot, in practice it is preferred to place the zip to one side and to have a cover over the zip as is known from waterproof jackets to inhibit the ingress of falling snow. It may also have a further zip 41 at the back to facilitate putting the cover on and to further facilitate walking. As its lower end 42 , the cover is elasticated and is designed to fit over the sole part of the frame. Conveniently, a groove within which the edge of the cover locates may be provided to provide a firm grip and to improve the appearance. On its inner side facing the other leg, the cover includes a tough "scuff pad" which protects the cover from the other boot and the adjacent ski.

It will be understood that alternative embodiments of the boot may be provided. For example the described embodiment uses pressed aluminium sheet but alternatively it may cast, or of magnesium alloy, which may be cast, or of a composite construction using plastic reinforced with carbon fibre, aramid fibres or glass fibres. It is envisaged that a variety of covers may be provided in order to, for example, match the wearer's skiing clothes or to incorporate a sponsor's logo. Although the drawings show the straps as held in by nuts and bolts, in practice, these may be bonded in with the material or flush fitting rivets to preserve a smooth exterior surface.

It has been found that the use of the adjustable mountings for the foot straps enables one boot size to accommodate feet covering at least two shoe sizes in width and length and also to more easily accommodate in comfort different shapes of foot, which gives significant economic advantages.

In this embodiment the boot attaches to conventional ski bindings via plastic heel and toe pieces which are screwed or bonded to the underside of the sole part 2. These pieces also facilitate walking in the boot when not skiing.

Although described with reference to a ski boot, it will be understood that the inventive concept, with an appropriate outer sole, may be utilised for footwear for other types of activity where lateral support is required, such as skating, rollerblading, or climbing.