GB2457045A - Collapsible boot - Google Patents

Abstract

A boot comprising a substantially rigid foot portion 20 and a leg portion 10 adapted to be collapsible, suitable for adjusting the height of the leg portion.

Description

1 2457045

DESCRIPTION

A BOOT

This invention relates to the design of boots and, in particular, to waterproof and other protective boots.

Boots are distinguished from other types of footwear by the fact that they extend to cover a region of the leg of the wearer above the foot and often above the ankle. This may be desirable for a number of reasons, including mechanical support, style, warmth or protection from harsh environments For example, one of the most popular designs of protective boot, the waterproof rubber boot commonly known as the "Wellington" boot, can protect the wearer completely from liquids to a depth up to the mid-calf or even knee. Such convenient protection is not without disadvantages, however.

Being fabricated generally in rubber, Wellington boots present an effective barrier not only to external liquids, but also to the perspiration of the wearer. This lack of breathability can result in discomfort from a build up of heat and moisture -rendered all the worse by the height of the boots on the leg.

The ideal leg-height, therefore, is that minimum necessary to protect against the maximum depth of liquid encountered, but since this will always vary it is difficult to predict in advance.

Previous solutions aimed at the problem of variable-depth protection have included the addition of gaiters or waders to boots or shoes, as in patent specification GB590395A, for example. This comes with the drawback that a perfect seal between shoe and gaiter may be difficult or impossible to achieve.

It may be possible to reduce the height of some boots by rolling down the top rim of the leg portion. The applicant has recognised that when this is done the exterior and interior surfaces of the leg portion will come into contact, potentially transferring the liquid from which the wearer is seeking to protect themselves onto the interior surface. Even if the boots are dry to begin with, by rolling or folding the rim outward (usually the easiest direction in practice), the interior is exposed on the folds or rolls to fresh splashes of liquid.

According to the current invention, there is provided a boot comprising a substantially rigid foot portion and a leg portion adapted to be linearly collapsible, suitable for adjusting the height of the leg portion.

In this context, linearly collapsible means that the rim of the leg portion is not folded or rolled, such that the interior and exterior surfaces of the wall of the leg portion do not contact one another as the height is reduced.

A rigid foot portion, as in a conventional boot, provides increased protection for the wearer's foot against, for example, impacts and mechanical 0 stresses. By collapsing, rather than rolling down, the leg portion fulfils the twin requirements of adjustable height and isolation of interior and exterior surfaces.

The boot of the invention allows the wearer to reconfigure the footwear to adapt to variable environmental conditions (according to depth of protection desired, ambient temperature and level of exertion, among others) while avoiding the need to attach separate parts (which may leak) and preserving the isolation of the interior and exterior surfaces.

Preferably, the leg portion is sufficiently rigid to support at least its own weight when extended. Also preferably, it is sufficiently flexible to remain collapsed under its own weight.

These two features serve to enhance the convenience of use for the wearer, since no additional fixing means are required to hold the leg portion in any particular state of extension or collapse. In the context of the prior art approach of rolling down the rim of a Wellington boot, the analogy is that the Wellington leg is stiff enough to stand upright but flexible enough to permit rolling without the rolls springing back upright.

Preferably, the collapsible leg portion is constructed of an elastic material -that is a material which has a degree of stretch and spring in at least one direction. This has obvious benefits of flexibility for the wearer in general and also can also contribute to the formation of a structure which collapses and extends easily.

Preferably, the collapsible leg portion comprises a plurality of joined, substantially cylindrical sections. These comprise the collapsing elements, which are arranged vertical'y to form the leg portion of the boot.

Preferably, the adjacent, joined, substantially cylindrical sections are adapted to fold in an overlapping concertina pattern as the leg portion is collapsed. This is a beneficial way to construct a collapsing leg portion from a single piece of material, the interior and exterior surfaces of which remain isolated when collapsed.

Preferably, the substantially cylindrical sections are joined by a plurality of flexible connecting sections. The flexible sections are designed to bend easily, essentially inducing the wall (comprised of the cylindrical sections) to fold naturally along these contours between the sections.

Preferably, at least one flexible connecting section comprises a localised weakness in a wall of the leg portion. This allows the wall to be constructed from a single contiguous piece of material, with potential benefits for the integrity of waterproofing. This weakening may be achieved, for example, by localised reduction in a thickness of the wall of the leg portion.

Preferably, at least one substantially cylindrical section is held in its extended position by elastic tension around its circumference when the leg portion is extended. Similarly preferably, at least one substantially cylindrical section is held in its collapsed position by elastic tension around its circumference when the leg portion is collapsed.

This allows the sections to snap into place when they are folded or unfolded, by the wearer, by exploiting tangential elastic forces. It means that the ability to hold its shape is integral to the material of the wall of the leg section Preferably, the substantially cylindrical sections are independently collapsible. This allows the height to be almost infinitely variable.

The invention wifl now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 shows an example of a boot according to the invention with the leg portion extended; Figure 2 shows the boot of Fig. I with the leg portion collapsed; Figure 3 is an example of a profile of the side-wall of the leg portion of a boot according to the invention, as the leg portion is about to be collapsed; Figure 4 shows the side-wall profile of Fig. 3 as the leg portion undergoes collapse; Figure 5 shows the side-wall profile of Figs. 3 and 4 in the final stage of collapse.

Note that the drawings are illustraUve and not necessarily to scale, As described above, the ability to alter the effective height of a protective boot is highly desirable, yet prior art techniques for providing boots of variable height (that is, for adjusting the effective height of the leg portion) suffer from a number of drawbacks.

The boot of Fig. 1 suffers from none of these. When the leg portion 10 is expanded to its full height, the boot functions exactly like any ordinary boot, protecting the wearer from the immediate environment of the lower leg.

However, when protection up to the full height is not required, the leg portion can be lowered (in successive stages, if necessary) to relieve negative effects such as the build-up of excess heat, excess moisture or chafing. The fully lowered configuration is shown in Fig. 2. The rigid foot portion 20 is unchanged between configurations.

Figs. 3 to 5 illustrate in greater detail the construction of the leg portion of such a boot. These diagrams show a profile of the side-wall of the boot. The profile is substantially the same all around the circumference. In Figs. 3-5, the tangential direction (that is, that parallel to the rim of the leg portion) is into (or out of) the page.

The leg portion 10 is comprised of a series of several substantially cylindrical sections 40 and 45 arranged vertically to form the wall of the leg portion. These rings are configured to fold through flexible connecting sections and 35, which join them together, in a cylindrical concertina as the leg portion is compressed. The connecting sections can comprise any means suitable for inducing folds at the joins between the more rigid cylindrical sections. For a waterproof rubber boot, with a leg-wall formed from a contiguous piece of approximately cylindrical rubber, for example, this can be achieved by selectively weakening the wall at the desired locations. Such weakening can be easily accomplished by thinning the rubber to an appropriate extent.

As downward pressure is applied by the wearer (shown by the vertical arrows in Fig. 3), the rings are configured to collapse in alternate directions, with one ring 40 folding inward and the next 45 folding outward.

Correspondingly, the connecting sections 35 flex or stretch alternately concavely and convexly. This alternate folding pattern allows the wall to collapse without the interior and exterior surfaces coming into contact with one another.

Advantageously, the material of the wall has an elastic component, enabling it to stretch and relax, at least in the tangential direction around the circumference of the rings The collapsible portion can then be designed so that each section is relaxed both in the folded position (shown in Fig. 5) and in the unfolded configuration (Fig. 3), while being stretched in the intermediate state of Fig. 4. This means that the leg sections snap into place and stay in a given configuration until force is applied to change the state. In terms of the operation of the boot, when the user pushes down on the rim, one or more sections will flip over to collapse; when the user is satisfied with the reduced height, the force is then removed and the leg portion is held in a stable configuration by the elastic tension. To raise the height, the process is reversed by pulling up on the rim.

The concertina arrangement allows not only extension and contraction of the length of the leg portion, but also articulation where necessary. This will be clear to anybody who has ever used bendable drinking straws, which additionally exhibit the elastic-snapping function described above. For a boot, such articulation may be desirable at the ankle or knee. There is no need to have prior knowledge of the length of, for example, the wearer's lower leg, since the concertina structure can flex at any point along its length.

Advantageously, the concertina can be constructed so that, when folded (collapsed), the substantially cylindrical sections slant down towards the exterior of the boot, in order to effectively shed fluids when the boot is used collapsed. Slanting down inwards may result in the collection of liquid in the folds. In the context of Fig. 5, this means that the left hand side of the figure represents the exterior and the right hand side the interior Note that the cylindrical sections may be constructed with the same heights, or varying heights -for example with alternating heights to facilitate the slanting structure shown in Fig. 5 The boot may be formed of rubber, including natural rubber (that is, elastic hydrocarbon polymer) or synthetic rubber. Synthetic rubbers such as styrene-butadiene rubber, butadiene rubber, chloroprene rubber and ethylene-propylene-diene rubber are well known to persons skilled in the art of boot manufacture. Other possible materials include, though are not limited to, polysiloxane (silicone), polychioroprene (neoprene) and polyvinyl chloride.

Boots, such as Wellington boots, are commonly lined on the interior surface with a fabric, for the improved comfort of the wearer. It may be beneficial to partially line boots made according to the invention. For example, the collapsible leg portion may be unlined to aid the flexing and bending of the wall. Alternatively, it may be lined with a stretchable textile such as an elastane (spandex), which has sufficient elasticity to permit unimpeded folding of the wall. The rigid foot portion may be lined, for example, with a cotton or cotton-nylon mix.

Claims (15)

1. A boot comprising a substantially rigid foot portion and a leg portion adapted to be linearly collapsible, suitable for adjusting the height of the leg portion.

2. The boot of claim 1, wherein the leg portion is sufficiently rigid to support at least its own weight when extended.

3 The boot of claim 1 or 2, wherein the leg portion is sufficiently flexible to remain collapsed under its own weight.

4. The boot of any preceding claim, wherein the collapsible leg portion is constructed of an elastic material.

5. The boot of any preceding claim, wherein the collapsible leg portion comprises a plurality of joined, substantially cylindrical sections.

6 The boot of claim 5, wherein adjacent, joined, substantially cylindrical sections are adapted to fold in an overlapping concertina pattern as the leg portion is collapsed.

7. The boot of claim 5 or 6, wherein the substantially cylindrical sections are joined by a plurality of flexible connecting sections.

8. The boot of claim 7, wherein at least one flexible connecting section comprises a localised weakness in a wall of the leg portion.

9. The boot of claim 8, wherein each flexible connecting section comprises a localised reduction in a thickness of the wall of the leg portion.

10. The boot of any of claims 5 to 9, wherein at least one substantially cylindrical section is held in its extended position by elastic tension around its circumference when the leg portion is extended.

11. The boot of any of claims 5 to 10, wherein at least one substantially cylindrical section is held in its collapsed position by elastic tension around its circumference when the leg portion is collapsed.

12. The boot of any of claims 5 to 11, wherein the substantially cylindrical sections are independently collapsible.

13. The boot of any preceding claim, wherein the boot is comprised of at least one of: polysiloxane; polychloroprene; and polyvinyl chloride.

14. The boot of any preceding claim, wherein the collapsible section is unlined and a remaining section of the interior surface is lined

15. The boot of claim 14, wherein a shin part of the collapsible section is lined with an elastane.