WO2011123941A1

WO2011123941A1 - Combination of internal shoe and external shoe and method of use

Info

Publication number: WO2011123941A1
Application number: PCT/CA2011/000373
Authority: WO
Inventors: Marc Kingsley-Poole; Robert Mahlous; Barry Hallenbeck
Original assignee: Marc Kingsley-Poole; Robert Mahlous; Barry Hallenbeck
Priority date: 2010-04-07
Filing date: 2011-04-07
Publication date: 2011-10-13

Abstract

The present invention provides a combination of an internal shoe and of an external shoe wherein the internal shoe can be worn alone or in combination with the external shoe. The combination performs like a high performance winter boot. The present invention is also providing an outsole which provides anti-slip properties while walking outside on soft surfaces, like snow, ice, mud, grass while minimising damage to harder indoor surfaces, like hardwood, tile, and linoleum floors.

Description

COMBINATION OF INTERNAL SHOE AND EXTERNAL SHOE AND METHOD

OF USE

Cross-Reference to Related Applications

[0001] The present patent application claims the benefits of priority of commonly assigned American Provisional Patent Application No. 61/321,694, entitled "Lightweight Specialised Overshoe System" and filed at the USPTO on April 7, 2010.

Field of the Invention

[0002] The present invention generally relates to a combination of an internal shoe and of an external shoe wherein the internal shoe can be worn alone or in combination with the external shoe. The present invention also relates to a non-slip outsole.

Background of the Invention

[0003] People typically spend most of each day indoors, but nearly everyone spends a part of the day commuting outdoors from one place to another. During cold weather and winter months, commuting often requires specialised footwear to protect feet from the elements. The need for specialised outdoor winter and cold weather footwear is important in cold climate. Winter boots must be waterproof, warm, protective and anti-slip. Although they perform well outdoors, winter boots are uncomfortable, cumbersome and unhealthy when worn indoors. Indoors shoes should preferably be lightweight, breathable, comfortable and appropriately styled. This dictates a need for two kinds of footwear on a daily basis in cold weather, requiring the carrying of shoes to and from our various destinations.

[0004] There are some inconvenient with shoe system of prior art: it is not practical to carry around and extra pair of indoor shoes when commuting in cold or winter weather; shoes that promote foot health indoors are not convenient outside in winter and cold weather conditions (and vice versa); the cost of redundant features is a wasted expense; the weight of carrying around a second pair of shoes when outdoors or boots when indoors is an unwanted burden; and Walking outdoors on ice and snow in the winter months is hazardous due to the danger of slipping and falling.

[0005] People have been wearing standard galoshes with their normal indoor shoes for many years now and the result is usually an unstylish, bulky and often heavy combination of footwear. This situation is unavoidable when one considers that galoshes have always necessarily been designed to fit, as well as possible, the greatest number of standard indoor shoes of a given size category without causing undue discomfort to the wearer. Neither the standard indoor shoe nor the galoshes are purpose-built for one another. Furthermore, galoshes are not designed to keep the feet warm in cold climate.

[0006] When wearing a set of standard galoshes, the user must accept the fact that these generic overshoes are bulky, heavy and made to the philosophy of "one size fits all". These are the detrimental trade-offs made to accommodate the general shoe-wearing population with a nearly universal solution.

Summary of the Invention

[0007] The present invention is generally providing shoe system comprising an internal shoe comprising a internal sole, a midsole and an external sole, wherein the internal shoe may be worn either as a component of the shoe system or by itself; an external shoe comprising a midsole and an external sole, wherein the external shoe does not comprises a midsole nor an insole; wherein the exterior of the internal shoe closely mates the interior of the external shoe, and wherein the external shoe is adapted to be worn only in combination with the internal shoe and wherein the function of the midsole is replaced by the presence of the midsole of the internal shoe.

[0008] The present invention is also providing an external shoe for use in combination with an external shoe comprising a internal sole, a midsole and an external sole, wherein the internal shoe may be worn either as a component of the combination or by itself, the external shoe comprising a midsole and an external sole, wherein the external shoe does not comprises a midsole nor an insole, wherein the exterior of the internal shoe closely mates the interior of the external shoe, and wherein the external shoe is adapted to be worn only in combination with the internal shoe and wherein the function of the midsole is replaced by the presence of the midsole of the internal shoe.

[0009] The present invention is also providing a non-slip outsole for footwear, having a bottom surface, the non-slip outsole comprising: at least one concave portion located under the forefoot area of the foot; a plurality of first rubber cleats comprising rubber tips extending from the outsole in the non-concave portion of the outsole; a plurality of second rubber cleats comprising studs, the studs comprising tips, wherein the second rubber cleats extend from the concave portion of the outsole.

[0010] The present invention provides the combination of an internal shoe and of an external shoe. The external shoe is configured to receive the internal shoe and is designed to be worn with the internal shoe. The internal shoe can either be worn alone or with the external shoe. The internal shoe is very lightweight and breathable with an insole (also known as foot bed), a cushioned midsole and an outsole. The internal shoe has all the basic elements of a comfort shoe to achieve a low total weight objective. The internal shoe is made of a very lightweight material (preferably ethylene propylene rubber - EPR) to provide traction, durability and adequate support indoors, while attaining the requirement for light weight and comfort.

[0011] The interior of the external shoe very closely matches the contours of the internal shoe's exterior. The internal shoe and the external shoe fit together securely. When worn together, the system replicates a high-performance winter or cold weather boot. The external shoe has neither a midsole nor an insole - these elements are provided by the internal shoe since the external shoe is worn with the internal shoe. Unlike the internal shoe, the external shoe has a rugged rubber outsole for support and durability on rough outdoor terrain. The external shoe is preferably waterproof and when worn together with the internal shoe, provides good insulation for the foot in cold or winter weather. However, it is to be understood that the insulation level of the present external shoe can be adapted to a variety of climate.

[0012] The midsole of the internal shoe is concealed inside the upper of the internal shoe. This makes the overall exterior surface of the internal shoe smoother than a normal shoe with a cushioning midsole and, thereby, makes sliding the internal shoe into the external shoe easier.

[0013] The internal shoe cannot shift inside the external shoe because the outer contour of the internal shoe so closely matches the inner contour of the external shoe. Not only is the shape of the internal shoe's outsole outline the same as the external shoe's interior but the arch relief in the internal shoe outsole is also matched by the external shoe's interior.

[0014] In order to offer a good solution to the user who is looking for optimal cold/winter weather foot protection, the combination of the external shoe and internal shoe is lightweight and not bulky. Otherwise, the resulting product could not be comfortably worn without discomfort and/or fatigue.

[0015] Achieving a lightweight, compact and comfortable high-performance cold/winter weather boot/shoe product is the key innovation that differentiates the present invention from galoshes worn with standard shoes or any other modular shoe concept available in the market today.

[0016] By design, an external shoe according to the present invention may be worn with any other internal shoe of the same size and design category. This important feature allows for variation of the aesthetics of the external shoe when worn with various models of internal shoes and vice versa. Thus the user may "mix and match" as desired to create variable fashion concepts, while retaining the primary functional advantages of this system: lightweight and low profile (non-bulky) footwear that is not uncomfortable, unfashionable or awkward to wear indoors and out.

[0017] The present invention is also providing a non-slip outsole which provides anti-slip properties while walking outside on slippery surfaces, like snow, ice, mud, grass while minimising damage to indoor surfaces, like hardwood, tile, and linoleum floors. This non- slip outsole comprises a first type of rubber cleat that comprises a rubber tip, and a second type of rubber cleat that comprises a metallic studs comprising a metallic tip. The non-slip outsole is designed with a plurality of rubber cleats having rubber tips, and a plurality of rubber cleats comprising special studs having a tip, the studs being preferably made from metal and more preferably comprising tungsten carbide and aluminum. The rubber cleats comprising the studs are placed in very specific locations on the non-slip outsole for most efficient traction and minimal discomfort when walking indoors. Typical cleated outdoor outsoles are flat bottomed at the forefoot portion and heel portion, but the present non-slip outsole is not. It is to be noted that the present non-slip outsole could be used alone for outdoor shoe or boot.

[0018] The shape of the non-slip outsole is concave in preferably two areas - the forefoot area and the heel area, and the rubber cleats comprising metallic studs are located in these concavities. The balance of the rubber cleats that do not comprises metallic studs are mainly positioned in the peripheral areas of the outsole that are not concave. This ensures that the metallic studs are not continually in contact with floor surfaces such as wood. The tips of the metallic studs are not in the same plane as the rubber tips of the rubber cleats that do not contain studs. The rubber cleats that do contain the metallic studs are placed in the concave portions of the non-slip outsole so they come into contact with the ground after the rubber cleats.

[0019] The first type of rubber cleats normally make initial contact with the floor or ground when walking or standing due to their position on the outsole as explained previously. This helps stabilise the shoe when walking and helps reduce or eliminate any lateral slipping which is another potential factor for causing scratching of an indoor floor surface by the cleats with metallic studs. Since most of the body weight is transferred to the floor surface via the cleats with rubber tips, lateral slipping is greatly reduced.

[0020] Contact is also ensured between the studs and the ice when the user wears a shoe comprising the non-slip outsole while running. This is due to the dynamic impact loading observed during running and jogging.

[0021] The geometry of the metallic studs is also important for minimising damage to the indoor flooring surfaces. The stud tip design geometry is such that it is optimised for minimal flooring damage or scratching while walking or standing indoors while wearing a shoe having the described non-slip outsole. In a preferred embodiment, this is achieved by ensuring the presence of a small radius on the extremity of the metallic stud. In this way, a convex shaped stud is in contact with the floor or ground. An optimal stud tip radius is 2mm, but radii between 1 and 3mm could be considered also. Further, the optimal height of the stud tip is 1.1mm, but the height could range from 0.4 to 1.7mm, for example, and still function. Finally, the diameter of the metal stud tip is optimally 2mm, while it could range from 1mm to 4mm. [0022] Preferably, the material of the stud is metal, but it could be ceramic or very hard and tough plastic. The stud could be made of aluminum, steel, tungsten carbide, ceramic or plastic. In a preferred embodiment, the stud is made of aluminum with a tungsten carbide tip or insert. The stud could also be made of hardened steel, with or without an anti-rust coating. Preferably, the stud is made of a hard, but not brittle wear-resistant surface, so it does not wear out too quickly with use.

[0023] In a preferred embodiment, the number of rubber cleat with metallic studs is four per region of concavity, for a total of eight metallic studs per non-slip outsole. Functionality can be achieved with as little as two metallic studs per region of concavity and as many as eight per region of concavity. Most ideally, each region of concavity comprises studs but the non- slip outsole could also be used with studs only in the forefoot area.

[0024] The advantage over non-slip outsole of prior art is that the described non-slip outsole feels more natural when walking on indoor surfaces. With other designs, the metallic studs are in direct contact with the floor and it has been found uncomfortable by users. With the present non-slip outsole, the metallic stud are not normally in direct contact with the floor.

[0025] There is a plurality of technical challenges that needed to be overcome to obtain the present invention.

• The internal shoe is designed to be worn with the external shoe and the two components, when worn together must mimic the performance of a one-piece high quality boot. The design geometry and material choices for the internal shoe and the external shoe are crucial for achieving these goals.

· The choice of lightweight materials and the elimination of certain redundant features was the only way to achieve acceptable weights for the internal shoe (when worn alone) and the combination system (when worn together). Donning the external shoe while wearing the internal shoe is critical and cannot be made with standard shoes (like putting on a shoe over a shoe). The exterior materials and design features of the internal shoe and the interior materials and design features of the external shoe must be optimised to facilitate the donning process. This is achieved, among other things, by choosing low-friction materials and incorporating features that aide the relative slipping/sliding process when pulling on the external shoe over the internal shoe. Also, the opening/closing mechanism of the external shoe is particularly designed so that the insertion and removal of the internal shoe from the external shoe is easy while the internal shoe is still stable in the external shoe.

Preventing relative motion of the shoe/boot system when being worn by the user: minimising the allowable spacing (gap) between the internal shoe and the external shoe and choice of materials is important to prevent possible longitudinal or lateral motion of the internal shoe within the external shoe while walking. Further design features of the internal shoe related to the retaining mechanism are crucial to ensuring very limited relative motion in the form of the internal shoe heel lifting off the inner surface of the external shoe supporting surface (strobel board material) while walking.

Allowing the user to walk safely on ice and other slippery surfaces with metal studs while not scratching indoor flooring surfaces.

[0026] In order for the combination or shoe system to be comfortably worn by the user, the total weight of the system should be as low as possible, but still sufficiently rigid and supportive to replicate the design performance of a one piece, high-quality cold weather boot. According to one variant of the invention, the overall weight per foot of a standard Men's size 9 (USA/Canada) or size 42 (Europe) external shoe/internal shoe combination should be in the 0.50 to 1.00 kg range. According to a preferred variant of the invention, the overall weight per foot of a standard Men's size 9 (USA/Canada) or size 42 (Europe) external shoe/internal shoe combination is in the 0.60 to 0.80 kg range. It shall be understood that the size 9/42 baseline is an industry standard reference size for shoes/boots and that the weights of smaller and larger sizes shall be proportionally lighter or heavier. The same scalability applies to Women's and Children's sizes. [0027] In one embodiment of the invention, the weight of the external shoe alone is between 0.30 and 0.55kg per foot for a standard Men's size 9 (USA/Canada) or size 42 (Europe) foot. In accordance with a more preferred embodiment, the weight of the external shoe alone is between 0.35 and 0.50kg per foot for a standard Men's size 9 (USA/Canada) or size 42 (Europe) foot.

[0028] The weight of the internal shoe is preferably in the 0.22 to 0.37kg range per foot for a standard Men's size 9 (USA/Canada) or size 42 (Europe) foot. In a more preferable embodiment, the weight per foot is in the 0.25 to 0.35kg range for a standard Men's size 9 (USA/Canada) or size 42 (Europe) foot.

[0029] In one embodiment of the invention, the exterior of the external shoe is waterproof over the majority of its surface area, starting upwardly from the top of the outsole. In a preferred embodiment, the waterproof area comprises at least 60% of the area, starting at the top of the outsole and extending upwardly continuously to the bottom of the collar. Although not essential, the waterproof quality of the external shoe is provided by a leather exterior surface in combination with an interior plastic liner extending upwardly from the top of the outsole to the lower surface of the external shoe collar. Alternatively, the waterproof quality may be provided by combinations of other materials such as Cordura, chemically treated leather and suede to render the external shoe waterproof. These later materials are preferable to render the external shoe stain resistant against exposure to water, snow, ice and salt, for example.

[0030] The outsole of the external shoe is preferably made of synthetic rubber.

[0031] In order for the internal shoe to be comfortable when worn alone and with the external shoe, it is preferably made using breathable materials. In one embodiment of the invention, the exterior surface of the internal shoe upper portion (starting upwardly from the top of the outsole) comprises layers consisting of air mesh fabric, suede or leather in combination with an inner layer of spun fibres.

[0032] The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. Brief Description of the Drawings

[0033] The above and other objects, features and advantages of the invention will become more readily apparent from the following description, reference being made to the accompanying drawings in which:

[0034] Figure 1 is a side view showing the internal shoe and the external shoe in combination.

[0035] Figures 2a to 2b are side views showing the insertion of a foot in the internal shoe, and the internal shoe in the external shoe.

[0036] Figure 3a is a side view of an embodiment of the external shoe.

[0037] Figure 3b is a top view of the external shoe shown in Fig. 3a.

[0038] Figure 3c is a rear view of the external shoe shown in Fig. 3a.

[0039] Figure 4a is a side view of an embodiment of the internal shoe.

[0040] Figure 4b is a top view of the internal shoe shown in Fig. 4b.

[0041] Figure 4c is another side view of an embodiment of the internal shoe

[0042] Figure 5a is a bottom view of the outsole of the internal shoe.

[0043] Figure 5b is a side view of the outsole shown in Fig. 5a.

[0044] Figure 5c is a cross-section view of the outsole shown in Fig. 5a, along A-A'.

[0045] Figure 6a is a bottom of the outsole of the internal shoe.

[0046] Figure 6b is a cross-section view of the outsole shown in Fig. 6a, along B1-B2.

[0047] Figure 6c is a cross-section view of the outsole shown in Fig. 6a, along C 1-C2.

[0048] Figure 6d is a cross-section view of the outsole shown in Fig. 6a, along D1-D2.

[0049] Figure 6e is a rear view of the outsole shown in Fig. 6a.

[0050] Figure 7a is a bottom view of the non-slip outsole.

[0051] Figure 7b is a cross-section view of the non-slip outsole of Fig. 7a, along A-Al .

[0052] Figure 8a is a rear view of the non-slip outsole of Fig. 7a.

[0053] Figure 8b is a cross-section view of the non-slip outsole of Fig. 7a, along B-Bl .

[0054] Figure 8c is a cross-section view of the non-slip outsole of Fig. 7a, along C-Cl .

[0055] Figure 9a is a schematic illustration of a concavity of non-slip outsole in the heel area.

[0056] Figure 9b is a schematic illustration of a concavity of non-slip outsole in the forefoot area.

[0057] Figure 9c is a schematic illustration of a concavity of non-slip outsole, along F-Fl [0058] Figure 10a is a cross-section view of the rubber studs of the non-slip outsole.

[0059] Figure 10b is a side view of an embodiment of a cleat.

[0060] Figure 10c is a side view of a further embodiment of a cleat.

[0061] Figure 11 is a side view of another embodiment of the external shoe.

Detailed Description of the Preferred Embodiment

[0062] A novel combination of internal shoe and external shoe and method of use will be described hereinafter. Although the invention is described in terms of specific illustrative embodiment(s), it is to be understood that the embodiment(s) described herein are by way of example only and that the scope of the invention is not intended to be limited thereby.

[0063] This invention relates to a lightweight external shoe and internal shoe system, particularly one with an external shoe that must be worn in combination with an internal shoe. This combination performs like a high performance cold weather boot. The combination comprises a lightweight external shoe and a matching lightweight internal shoe. More particularly, the internal shoe may be worn alone and is designed to also act as a high quality indoor comfort shoe. [0064] The external shoe is not designed to be worn alone as it does not contain certain standard shoe/boot components that a stand-alone shoe or boot would normally have, namely an insole and a midsole.

[0065] Referring to Fig. 1 and 2, the present invention discloses a shoe system 100 comprising an internal shoe 200 that can either be worn alone or with an external shoe 300. The internal shoe 200 is very lightweight and breathable having an insole, a cushioned midsole and an outsole. The internal shoe 200 has all the basic elements of a comfort shoe to achieve a low total weight objective. The internal shoe 200 is made of a very lightweight material (preferably ethylene propylene rubber - EPR) to provide traction, durability and adequate support indoors, while attaining the requirement for light weight and comfort. The external shoe 300 is configured to receive the internal shoe 200.

[0066] In order to achieve the lightweight objective of the external shoe 300, it preferably does not comprise a midsole not an insole, since this foot support function is provided by the presence of the midsole an insole of the internal shoe 200. In a further embodiment, the external shoe 300 has a low-profile, low-friction, centrally located closing device 305, preferably comprising a zipper. In other embodiments, the closing device 305 may comprise laces, Velcro attachments or other means. In a preferred embodiment, the length of the closing device 305 is preferably at least 50% of the distance from the forward most portion of the external shoe toe to the forward portion of the external shoe collar 307 to facilitate insertion of the foot shod with the internal shoe 200 into the external shoe 300. The length of the opening device 305 is to be adapted to the height and length of the external shoe 300. For example, in the embodiment of external shoe 300 shown in Fig. 1, the height of the external shoe 300 is lower than the height of the external shoe 600 shown in Fig, 3.

[0067] Figs 2a to 2d are sequential view illustrating the donning of the internal shoe 200 on the foot and the donning of the external shoe 300 over the internal shoe 200. In Fig. 2a and 2b, the user insert is foot in the internal shoe 200. In Fig. 2c, the user inserts his foot, bearing the internal shoe 200, in the external shoe 300 while the closing device 305 is opened. In Fig. 2d, the internal shoe 200 is completely inserted in the external shoe 300 and the closing device 305 is closed.

[0068] In a preferred embodiment, the zipper comprises locking mechanism to prevent it to open while the user is walking with the external shoe 300.

[0069] Figs 3a to 3b show an embodiment of the external shoe 600. This embodiment is taller than the embodiment shown in Fig. 2 and Fig. 1 1. The external shoe 600 comprises a closing device 605 starting over the toe area and extending up to the collar 607. The configuration of the closing device is critical to allow a user to be able to insert the internal shoe in the external shoe. If the closing device is not long enough, the user won't be able to insert the internal shoe in the external shoe. The extension 608 gives a grip to the external shoe 600 while a user is inserting the internal shoe in the external shoe 600. [0070] In a further embodiment of the invention, the material choice of the external shoe 607 collar is such that the collar 607 is durable, easily grasped by the user while donning the external shoe 600 while wearing the internal shoe 200 and at the same time be low friction enough to not hinder the donning process. The material of the external shoe collar 607 and collar liner is preferably of Lycra™. [0071] As shown in Figs 4 A and 4B, in one embodiment of the invention, the internal shoe 200 has a plurality of centrally-located smooth, low-friction longitudinal strips 202, 204, 206 on its upper surface to help reduce the friction between the internal shoe 200 and the external shoe 300 when donning the external shoe 300 over the internal shoe 200. In a preferred embodiment, the number of longitudinal strips is three and they are preferably made of smooth materials like suede, leather or rubber. In a preferred embodiment, the internal shoe 200 comprises a central longitudinal strip 204 and two lateral longitudinal strips 202 and 206.

[0072] Still referring to Figs. 4 A and 4B, in order for the internal shoe 200 to maintain a close fit with the foot of the wearer and avoid binding while donning the external shoe 300, the internal shoe 200 preferably has a plurality of centrally located, self-adjusting elastic retaining straps 210, 212, 214. More preferably, there are two and most preferably three retaining straps on the internal shoe 200. In an embodiment, the retaining straps are as short as possible and not very stretchable to help keep the foot well-anchored within the internal shoe 200, but still enough stretchable to prevent causing discomfort to the wearer. The three retaining straps 210, 212, 214 are preferably connected to the longitudinal strips 202, 204, 206 for the purposes of keeping the internal shoe 200 close to the foot at all times, whether being worn with or without the external shoe 300. The retaining straps 210, 212, 214 are preferably sewn to the longitudinal strips 202, 204, 206 and most preferably sewn to the underside of the longitudinal strips 202, 204, 206 such that the retaining straps 210, 212, 214 are located in a plane just below the longitudinal strips 202, 204, 206 to prevent binding when donning the external shoe 300 over the internal shoe 200.

[0073] In an embodiment of the invention, the entire lower circumference of the internal shoe 200 comprises a low-friction band 220 to facilitate donning of the external shoe 300. In a further embodiment, the low-friction material is suede, leather, nylon, polyester or silicone plastic. In a further embodiment of the invention, the height of the band 220 extends upwardly from the outsole for at least ¼ of the internal shoe 200 height at any given point in the circumference. In another embodiment of the invention, the low-friction band 220 of the internal shoe 200 extends upwardly from the outsole at least halfway and preferably all the way to the internal shoe 200 collar at the region of the heel. [0074] Figs 5 and 6 show the outsole 401 and midsole 402 of the internal shoe 200. In order to further facilitate donning of the external shoe 300, the outsole 400 of the internal shoe 200 comprises preferably a plurality of longitudinal ridges 405, 410. In an embodiment of the invention, the ridges 405, 410 extend over the forefoot area 412 and over the heel area 413. In an embodiment of the invention, the number of longitudinal ridges 410 is at least two and preferably at least four in the heel area 413. In a further embodiment, the number of ridges 405 in the forefoot area 412 is at least three, preferably six and most preferably eight.

[0075] In an embodiment of the invention, the outsole 400 of the internal shoe 200 is preferably designed on a last which is slightly concave. The radius of the concavity imparts a curvature to the forefoot area 412 of the outsole 400 of the internal shoe 200 and permits the internal shoe 200 to better mimic the form of the human foot that the wearer normally adopts with their shod foot when donning the external shoe 300. According to a preferred variant of the invention, the radius of the concavity of the internal shoe is between 180 and 220mm, more preferably between 190 and 210mm and ideally 200mm.

[0076] In a further embodiment of the invention, the outsole 401 and the midsole 402 of the internal shoe sole 400 are curved toward the toe with a first angle 420 between 3° and 7°. More preferably, the first angle is between 4° and 6° and most preferably between 4.5 and 5.5° to facilitate donning of the external shoe.

[0077] In a preferred variant of the invention, the internal shoe last also has a high toe spring 415 which helps create the curved effect which also helps make it easier to insert the internal shoe 200 into the external shoe 300. The radius of the toe spring curvature is 200mm in a preferred embodiment.

[0078] In an embodiment of the invention, the internal shoe 200 has a narrower / tighter profile with respect to the foot of the wearer compared to ordinary shoes to assist in reducing or eliminating relative motion between the internal shoe 200 and the external shoe 300 such that the internal shoe 200 more closely follows the foot contour and a nearly perfect fit inside the external shoe 300 is achieved. The design of the internal shoe 200 profile includes a gap that is preferably less than 2 mm (this value may vary) between the internal shoe interior and foot exterior at any point in the interior of the internal shoe 200. [0079] In a further embodiment of the invention, it is also important to ensure that the combination of the internal shoe 200 and external shoe 300 is not too bulky. A bulky internal shoe 200 would require a larger profile external shoe 300 and could render walking cumbersome and uncomfortable. Further, any slipping motion of the internal shoe 200 with respect to the external shoe 300 may cause undesirable friction to the wearer and instability when walking or running and should be avoided as much as possible. In a preferred embodiment of the invention, the design of the shoe system includes a gap that is preferably less than 2 mm (this value may vary) between the internal shoe 200 exterior and external shoe 300 interior.

[0080] In a preferred embodiment, the internal shoe 300 is also shorter in its exterior total length than ordinary shoes to allow it to be worn under the external shoe 300 without rendering the combination too bulky. The internal shoe 200 is preferably shorter (about 15 mm) in exterior length than a standard sport shoe of the same size and model.

[0081] Figs 7, 8 and 9 refer to the non-slip outsole 500. As shown in Fig. 7, an embodiment of the non-slip outsole 500 contains a plurality of rubber cleats 510, and a plurality of rubber cleats 505 comprising metallic studs 507 for increased traction when walking on ice, snow and other slippery surfaces. It is to be understood that the non-slip outsole shown herein could be used with any type of shoe or boot.

[0082] The shape of the non-slip outsole 500 is concave in at least two areas 515 and 520 - the forefoot area 512 and the heel area 513 of the non-slip outsole 500. This ensures that the metallic studs 507 are not continually in contact with floor surfaces such as wood, etc, but are in contact with harder surfaces, like ice. This is achieved by introducing concavities in the non-slip outsole 500 forefoot area 512 and heel area 513. The tips of the metallic studs 507 are not in the same plane as the tips of the rubber cleats 505 that do not contain any studs. The rubber cleats 505, that do contain metallic studs, are placed in the concave portions 515 and 520 of the nono-slip outsole 500 so they come into contact with the ground last.

[0083] Figs 9a to 9c are schematic illustrations showing exaggerated concavities to better illustrates the concept. [0084] Contact is also ensured between the studs 507 and the ice when the user wears a shoe comprising the non-slip outsole 500 while running. This is due to the dynamic impact loading observed during running and jogging. [0085] The shape of the studs 507 is as important as their placement on the outsole 500. As shown in Figs 10a to 10c, the studs 507 have a specific protruding tip 520 defining a shoulder 522. This design, along with the particular placement aides in obtaining a good grip on slippery surfaces, but minimises the risk of scratching indoor floor surfaces. [0086] In a further embodiment of the invention, the studs are designed with chamfered or rounded tips 524 whereby this tip design minimises possible scratching of indoor flooring surfaces, while maintaining efficacy on slippery surfaces. Figure 10b illustrates a stud comprising a tip having a convex shape 526, further minimizing the risk of scratching indoor floor surfaces.

[0087] While illustrative and presently preferred embodiment(s) of the invention have been described in detail hereinabove, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.

Claims

1) A shoe system comprising:

a) an internal shoe comprising a internal sole, a midsole and an external sole, wherein said internal shoe may be worn either as a component of the shoe system or by itself;

b) an external shoe comprising a midsole and an external sole, wherein the external shoe does not comprises a midsole nor an insole;

wherein the exterior of said internal shoe closely mates the interior of said external shoe, and wherein said external shoe is adapted to be worn only in combination with said internal shoe and wherein the function of the midsole is replaced by the presence of the midsole of the internal shoe.

2) The shoe system of claim 1, wherein the combination of said external shoe and said internal shoe weight is between 1.00 kilograms and 0.50 kilograms per foot for a standard Men's Size 9 (USA/Canada),or Size 42 (Europe) foot.

3) The shoe system of claim 1, wherein the combination of said external shoe and said internal shoe weight is between 0.80 kilograms and 0.60 kilograms per foot for a standard Men's Size 9 (USA/Canada), or Size 42 (Europe) foot.

4) The shoe system of claim 1, wherein said external shoe weight is between 0.55 kilograms and 0.30 kilograms per foot for a standard Men's Size 9 (USA/Canada), or Size 42 (Europe) foot.

5) The shoe system of claim 1, wherein said external shoe weight is between 0.50 kilograms and 0.35 kilograms per foot for a standard Men's Size 9 (USA/Canada),or Size 42 (Europe) foot. 6) The shoe system of claim 1, wherein said internal shoe weight is between 0.37 kilograms and 0.22 kilograms per foot for a standard Men's Size 9 (USA/Canada),or Size 42 (Europe) foot. 7) The shoe system of claim 1, wherein said internal shoe weight is between 0.32 kilograms and 0.25 kilograms per foot for a standard Men's Size 9 (USA/Canada),or Size 42 (Europe) foot. 8) The shoe system of claim 1, wherein said external shoe is made of waterproof material.

9) The shoe system of claim 1, wherein said outsole of said internal shoe and of said external shoe are made from a synthetic rubber. 10) The shoe system of claim 1, wherein said internal shoe is made of breathable materials.

1 1) The shoe system of claim 10), wherein said breathable material is selected from the group consisting of air mesh fabric material, suede, leather and spun fibres. 12) The shoe system of claim 1, wherein said external shoe further comprises a closing device located in its upper surface.

13) The shoe system of claim 12), wherein said closing device is selected from the group consisting of zipper, laces and Velcro™.

14) The shoe system of claim 1, wherein said internal shoe further comprises a plurality of longitudinal strips made from low-friction material extending from the forefoot area of said internal shoe toe to the collar of said internal shoe. 15) The shoe system of claim 14), wherein said longitudinal strip is made from a material selected from the group consisting of suede, leather and rubber.

16) The shoe system of claim 1, wherein the entire forward upper exterior surface of said internal shoe is made from a material selected from the group consisting of suede, leather and rubber.

17) The shoe system of claim 1, wherein said internal shoe further comprises a plurality of elastic retaining straps. 18) The shoe system of claim 14), wherein said internal shoe further comprises a plurality of elastic retaining straps that connected to said longitudinal strips are that are located in a plane just below said longitudinal strips. 19) The shoe system of claim 1, wherein said external shoe comprises a band of low-friction material.

20) The shoe system of claim 19), wherein the low-friction material is selected from the group consisting of suede, leather, nylon, polyester and silicone plastic.

21) The shoe system of claim 19), wherein said band extends upwardly from the outsole to the collar of said internal shoe.

22) The shoe system of claim 1, wherein said internal shoe outsole comprises a plurality of longitudinal raised ridges.

23) The shoe system of claim 22), where the number of said raised ridges is at least three on the heel area. 24) The shoe system of claim 22), where the number of said raised ridges is at least three on the forefoot area.

25) The shoe system of claim 1, wherein said forefoot area of said internal shoe outsole has radius of curvature of between 180 and 220 mm.

26) The shoe system of claim 1, wherein said forefoot area of said internal shoe outsole has radius of curvature of between 190 and 210 mm.

27) The shoe system of claim 1, wherein said forefoot area of said internal shoe outsole has radius of curvature of 200 mm.

28) The shoe system of claim 1, wherein said internal shoe outsole and midsole are curved toward the toe with a first angle of between 3° and 7°. 29) The shoe system of claim 1, wherein said internal shoe outsole and midsole are curved toward the toe with a first angle of between 4° and 6°.

30) The shoe system of claim 1, wherein said internal shoe outsole and midsole are curved toward the toe with a first angle of between 4,5° and 5,5°.

31) The shoe system of claim 1, wherein the shoe toe spring curvature radius of said internal shoe outsole is 200mm. 32) The shoe system of claim 1, wherein the gap between the foot of a user and the internal surface of said internal shoe is less than 2 mm.

33) The shoe system of claim 1, wherein the gap between said internal shoe exterior and said external shoe interior is less than 1 mm.

34) The shoe system of claim 1, wherein said internal shoe length is 15 mm shorter than a standard shoe of the same size when measured from the base of the heel to the tip of the toe. 35) The shoe system of claim 1, wherein said external shoe comprises a collar and a collar liner, and wherein said collar and said collar liner are made of a low-friction Lycra™ material.

36) An external shoe for use in combination with an external shoe comprising a internal sole, a midsole and an external sole, wherein said internal shoe may be worn either as a component of the combination or by itself, said external shoe comprising a midsole and an external sole, wherein the external shoe does not comprises a midsole nor an insole, wherein the exterior of said internal shoe closely mates the interior of said external shoe, and wherein said external shoe is adapted to be worn only in combination with said internal shoe and wherein the function of the midsole is replaced by the presence of the midsole of the internal shoe.

37) A non-slip outsole for footwear, having a bottom surface, said non-slip outsole comprising: a) at least one concave portion located under the forefoot area of the foot;

b) a plurality of first rubber cleats comprising rubber tips extending from said outsole in the non-concave portion of said outsole;

c) a plurality of second rubber cleats comprising studs, said studs comprising tips, wherein said second rubber cleats extend from said concave portion of said outsole.

38) The non-slip outsole of claim 37), further comprising a concave portion in the heel area, and wherein said concave portion in said heel area comprises at least one second rubber cleat comprising a stud.

39) The non-slip outsole of claim 37), wherein said stud is made from a material selected from the group consisting of aluminum, steel, hardened steel, tungsten carbide, ceramic and plastic.

40) The non-slip outsole of claim 37), wherein said tip of said stud is made from tungsten carbide.

41) The non-slip outsole of claim 37), wherein said tip of said stud is chamfered.

42) The non-slip outsole of claim 37), wherein said tip of said stud is rounded.

43) The non-slip outsole of claim 37), wherein said tip of said stud is convex.