The present invention relates to a method for manufacturing a protective overshoe, and to an improved protective overshoe. Background of the invention

Overshoes are commonly used by a variety of professionals and are disposed over a primary footwear, see by way of example US patents no. 6 023 856, 4 103 439 and 4 779 360. Today, a wide range of overshoe models are available on the market, addressing a wide range of industries, such as hospitals, bathing, craftsmen, sportsmen and more. The appropriate features of such overshoes depend on the area of application and may therefore vary considerably.

A problem with the overshoes found in the prior art is that they are not fully suitable for use in the building industry where a construction worker wearing the overshoe may enter a building from a wet and dirty environment and walk across sensitive (easily damaged) building flooring and up/down ladders, to work in different body positions, such as standing up or kneeling down.

Overshoes for such a purpose should be easy to put on a pair of shoes while worn by a construction worker, without requiring the worker to spend too much time, as inconveniences may cause the worker to refrain from wearing the overshoes, despite being required to.

Summary of the invention

The present invention provides an improved overshoe for particular use in the building industry and which is easy to apply.

The inventive overshoe provides internal friction between the inside of the overshoe and the worker's own shoe as well as flooring protection by reducing the risk that grains of sand or other hard particles on the sole of the worker's shoes leave marks/cuts on the building flooring through the overshoe. Lack of such internal friction may give rise to a shoe slipping internally in the overshoe, resulting in a poor user experience and in worst case hazardous outcomes, such as if happening while the worker is moving up/down a ladder. Marks as mentioned may give rise to subsequent repair costs on the side of the builder which should be avoided.

In particular, with the invention external friction between the overshoe and the building flooring as well as protection of the building flooring is available not only when the worker is in a standing position but also where he is kneeling in a position with the upper side of his toes against the flooring. At the same time, seepage of water through the base (sole) of the overshoe is prevented whereby the building flooring will remain dry.

To allow easy insertion of a shoe into the overshoe a mid-foot part of the overshoe of the invention is manually elastically stretchable with a relatively low resistance and the overshoe is maintained on the wearer's shoe through the resiliency of this stretchable mid-foot part, without the need for laces or other attachments, although such other attachments may be incorporated into the overshoe. The remaining portions of the overshoe are also stretchable, though requiring a larger force for a given deformation due to an external coating substance forming an integral part of those remaining portions, in particular at the base of the overshoe. This allows for the overshoe to be applied to different shoe sizes within a given range, permitting the overshoe itself to be made in few sizes.

The invention also relates to a cost-effective method of manufacture of such an easy to use overshoe which addresses the above issues, may have durability for reuse and yet is sufficiently inexpensive for disposal, In one embodiment this object is achieved by providing a method of manufacture of an overshoe wherein internal grip spots are formed simultaneously as the overshoe is supplied with the aforementioned external coating substance.

The method of manufacture comprises a number of steps. A first step comprises the providing of a flexible and stretchable sock having a mesh- structure, the fabric defining a base, a heel, a top and opposite lateral parts of the sock, the top including a toe-part and the mid-foot part, an opening of the sock giving access to the inside of the sock being delimited by the heel, the mid-foot part and the lateral parts, the opening preferably being elongated and preferably having a length of at least 50%, preferably of between 50% and 65%, of the length of the sock.

A subsequent step includes mounting this sock on to a frame or similar which stretches/expands the sock by opening-up the mesh structure of the sock.

Following this step is a dipping or immersing step wherein the so stretched sock is immersed into a liquid curable elastomeric substance to the extent that the base of the sock is fully immersed such that an external coating is achieved on the entire external side of the base. The toe-part of the sock is also immersed; however, the mid-foot part of the sock is kept free of the elastomeric substance. As the dipping step is carried out, the substance is allowed to migrate fully or partially through the opened-up mesh, to anchor the substance. In one embodiment the coating substance is allowed to migrate into the inside of the sock, to form a coating layer on the inside surface of the base. Thereby is achieved an internal friction surface during the dipping process.

The substance applied onto the external side of the base of the sock generally fills the mesh-openings to provide - after curing - reinforcement, water tightness and protection of building flooring against marks caused by particles on the shoe of a construction worker. Where the coating substance is not at this process step allowed to migrate into the inside of the sock, the sock is provided with an elastomeric coating substance on the interior face or side of the base of the sock in a separate process step either before or after the dipping step. In this separate process coating substance may be applied, such as through screen printing or spraying, to form an inside continuous layer on the base of the sock or to form discrete areas providing friction, such as in the form of dots or similar. Preferably, this separate process steps involves first inverting the sock to apply the coating substance, and then re-inverting the sock, after which the dipping step is preferably performed on the sock now carrying the coating material on the inside.

In one or more embodiments of the invention, the sock comprises a seamless stretchable material which may be knitted or woven from any suitable material e.g. nylon or textile. Preferably, the aforementioned elastic stretching is by mounting the sock on to a frame, preferably a frame having the shape of a last, and the sock is removed from the frame only after full or partial curing of the elastomeric substance, wherein the opening up of the mesh-structure of the fabric defining the base is maintained during the curing. The ratio between the length of the sock opening relative to the length of the sock will then be essentially maintained as the sock is maintained in its stretched configuration by the cured elastomeric material, whereby the aforementioned ratio is essentially the same for the sock as for the finished overshoe.

In one embodiment of the invention, the aforementioned last frame comprises a porous structure which allows migration of the coating substance into the inside of the sock. In a preferred embodiment, the last frame comprises metal and/or plastic bars or strings. In one embodiment of the invention, holes in the part of the fabric defining the base may be formed, such as during the process of weaving the sock. The holes may be arranged according to a predetermined pattern to provide a suitable friction pattern, in addition to the one provided by the coating material flowing through the opened-up mesh, and may also extend to surfaces adjacent the sole layer such as the toe section, heel section or side surfaces. Generally, for this embodiment such holes may be created on those surfaces intended to be coated. In one embodiment of the invention, the disclosed method further comprises the step of creating an external friction pattern on the external coating of the sock, such as in the upper toe area. For example, this may be achieved by subjecting the external coating to a patterned surface prior curing whereby the patterned surface will function as a mold for the pattern or such friction pattern may be achieved post curing of the external coating by means of tooling or machining.

By way of example, for the finished overshoe the toe-part may have an extension along a longitudinal axis of the overshoe extending from the front tip of the overshoe to the heel in the order of 10% of the total length of the overshoe, while the mid-foot part will have an extension along the same axis in the order of 25% of the total length of the overshoe, with the opening representing the remaining about 65% of the total length along the same longitudinal axis. Preferably, for the finished overshoe the surface area of the uncoated stretchable mid-foot part defined by the stretchable fabric may represent about 25%, preferably around 20%-30%, of the surface area of the top of the overshoe.

The invention also relates to an overshoe comprising a sock of an elastically stretchable fabric having a mesh-structure, and comprising a heel, an elastic flexible base, a top, opposite lateral parts, the top including a toe-part and a mid-foot part, an opening giving access to the inside of the overshoe being delimited by the heel, the mid-foot part and the lateral parts, the opening preferably being elongated and preferably having a length of at least 50%, preferably of between 50% and 65%, of the length of the overshoe, the flexible base comprising the fabric of the sock carrying on the entire external side and on the entire or parts of the internal side a cured elastomeric substance. The toe-part carries on the external side a layer of the cured elastomeric substance while the mid-foot part carries no coating of the elastomeric substance. The elastic flexible base has such an elasticity, through selection of the elastomeric substance, in a direction between the opposite lateral parts that it is stiffer than the elastic mid-foot part, preferably with Young's modulus of the base being at least 50%, such as 150% higher, such as at least 200% higher, or even at least 850% higher, in the direction between the opposite side parts. Preferably, Young's modulus is increased by between 50% and 100%. The flexibility of the base referred to is preferably such as to allow the overshoe to be folded or doubled upon itself.

Further objects, features, advantages and properties of the protective sock and the method of manufacture of the same according to the invention will become apparent from the detailed description.

Brief description of the drawings

In the following detailed portion of the present description, the invention will be explained in more detail with reference to the exemplary embodiments shown in the drawings, in which:

Fig. 1 is a perspective view of one embodiment of the a sock for making the overshoe according to the invention, Fig. 2 is a perspective view of the sock of fig. 1 , on a last frame fitted inside the sock and after dipping,

Fig. 3 is a perspective view of a finished overshoe according to one embodiment of the invention,

Fig. 4a and 4b shows a top and perspective view, respectively, of a finished overshoe according to another embodiment of the invention,

Fig. 5 is a sketch illustrating the migration of coating substance through holes/openings of the sock, and

Figs. 6a, 6b and 6c are bottom, perspective and top views, respectively, of another embodiment of the invention where no internal layer is formed at the dipping step, internal coating material having been applied in a separate process step.

Detailed description of the invention

In the following detailed description a protective overshoe 10 shown in figs. 3, 4a and 6b according to the invention will be described with reference to presently preferred embodiments. A method of manufacturing an overshoe 10 of the type illustrated in figs. 3, 4a and 6b will also be discussed.

The overshoe 10 is intended to receive a shoe, such as a shoe of a person working in a building where direct contact with the sole of the shoe is undesired. Referring first to figs. 1 and 2, the manufacturing method of the invention involves a number of steps.

A first step is the provision of a sock-like body 1 1 , in the following simply referred to as a "sock" due to the similarity of the body to a conventional sock, of suitable material. Fig. 1 shows the sock 1 1 with a shape as it appears when fitted onto an object (not shown) having the general shape of a foot; often the unfitted sock 1 1 will be a somewhat flat body, as a conventional sock for wearing directly on a person's foot.

The sock 1 1 of fig. 1 will be discussed in the following, before explaining the next steps of the manufacturing method.

The sock 1 1 is formed from a fabric which, as for conventional socks for wearing on a foot, defines a sole or base 13, a heel 16, an upper or top 18, and two opposite lateral parts 15 of the sock 1 1 . The term "fabric" as used herein may refer to a material with variations in structure; in other words, the fabric may include areas having different properties - by way of example, the structure of the fabric forming the area defining the heel 16 may be different from that of the lateral parts 15; however, preferably there will be no such variations in the structure.

As shown in fig. 1 the top 18 includes a toe-part 17 and a mid-foot part 14, where the toe-part 17 is the part of the top 18 more or less overlying the toe of a person wearing the shoe having the finished overshoe 10; the two opposite lateral parts 15 extend from the heel 16 along the mid-foot part 14 on either side thereof.

An opening 19 which gives access to the inside of the sock 1 1 is delimited by the heel 16, the mid-foot part 14 and a portion of the lateral parts 15. The opening 19 preferably is elongated with an oval shape, viewed from above, and preferably has a maximum length L2 from heel to mid-foot part 14 of at least 50%, preferably of between 50% and 65%, of the length L1 from the heel 16 to the tip of the sock 1 1 . As such, the length and shape of the opening normally differs from the opening provided in conventional socks for wearing directly on a foot, to allow for a shoe or boot to be inserted into the finished overshoe 10 by widening the opening 19, as discussed below. The aforementioned fabric is flexible and elastically stretchable such that the mid-foot part 14 may be stretched by manually applying oppositely directed forces F to the finished overshoe 10, as shown in fig. 4a, to allow a shoe, preferably being worn by a user, to be introduced through the opening 19 after some widening thereof, resulting from the aforementioned stretching.

The height of the sock 1 1 , measured from the base 13 to the rim R of the opening 19 when the sock 1 1 assumes the fitted shape shown in fig. 1 , is preferably such that the rim R of the opening 19 will bear either against the ankle of the person wearing the shoe or against or below the ankle portion of the shoe inserted into the finished overshoe 10. In this manner the finished overshoe 10 may be held onto the shoe with a proper fit and force determined by the extent to which the mid-foot part 14 remains partially stretched and under tension.

For easy manufacturing of the overshoe 10 of the present invention the sock fabric has a mesh-structure. The mesh-structure is such that stretching the fabric, in at least one direction, opens up the mesh-structure, by widening the mesh-openings. Depending of the intended use of the overshoe 10, the fabric may be water repellent.

In a preferred embodiment of the invention, the fabric is a stretchable seamless nylon knit; alternatively, nylon and/or polyester knits with or without elastane (commonly known as Spandex or Lycra) may be used. In further embodiments, the sock 1 1 may be knitted such that cuffs are integrated in the sock 1 1 . Cuffs may provide increased resilience and durability in sections of the sock 1 1 being subjected to frequent elevated tensioning or wear. Cuffs may for example be suitable around the aperture 19 to define the aforementioned rim R, around the heel portion 16 or the toe-part 17, to improve proper fitting of the protective sock 1 1 . Now referring to fig. 2, in the subsequent step of the method of the present invention, the sock 1 1 is arranged on a frame 25 with a shape corresponding largely to that of the finished overshoe 10 but preferably oversized to provide for an expansion of the sock 1 1 by stretching at least the portion of the fabric defining the base 13, conveniently at least or only in the direction between the lateral sides 15, thereby opening up the mesh-structure of the area of the fabric defining the base 13.

Still referring to Fig. 2, the next step includes the dipping of the sock 1 1 into a vessel while on the frame 25. The dipping step may for example be carried out by hand or by an automated or semi-automated machine.

The frame 25 is preferably constructed to allow natural migration of a coating substance from the outside towards the inside 21 of the sock 1 1 mounted on the frame 25. In one embodiment of the invention shown in fig. 2, the frame 25 constitutes metal or plastic wiring or like which is shaped into a last such that it may hold the sock 1 1 in the desired shape (similar to the shape shown in fig. 1 ) while stretching the base 13. Due to the open surface structure of such a last frame 25, such a coating substance is able to migrate/penetrate from the outside surface of the stretched base 13, through the opened-up mesh-structure, and then spread uniformly on the inside surface or side of the fabric defining the base 13.

The sock 1 1 partially is dipped into a liquid elastomeric substance held in the vessel such that an external coating layer 12, seen in fig. 2, of a desired thickness is formed on selected external surfaces of the sock 1 1 , while leaving the mid-foot part 14 uncoated by avoiding any dipping thereof. Preferably, in addition to coating layer 12 on the base 13, a lower part of the lateral parts 15 and the toe-part 17 is also provided with such an external coating layer 12, as such sections are typically subjected to increased wear. A suitable composition of the elastomeric substance may be chosen depending on the purpose of use of the overshoe 10. The coating substance may comprise a vulcanizable natural or synthetic elastic polymer. Non- limiting examples of materials which may be suitable include nitrile or latex rubber, crude rubber or silicone rubber.

During the step of dipping the sock 1 1 in the coating substance, the coating substance will migrate through the base 13, through the mesh-openings opened-up by the aforementioned stretching by the frame 25. As the coating substance migrates through the opened-up mesh-openings of the fabric, an internal coating layer forms on the inside of the sock 1 1 , more particularly on the inside of the stretched base 13 of the sock 1 1 . This internal layer will upon curing form a high-friction internal surface which prevents a shoe inserted into the overshoe 10 from slipping relative to the overshoe 10.

In the drawings showing the finished overshoe 10 portions of the sock modified in the dipping process are identified by the same numerals used in fig. 1 , but with an apostrophe added. The external coating layer 12 formed on the base 13 of the sock 1 1 defines a high-friction surface whereby a person wearing the overshoe 10 may walk safely without slipping; the coating layer 12 on the toe-part 17 prevents slipping when the user is in a kneeled-down working position with the toe-part 17 contacting a floor, with the modified base 13' facing upwards. More specifically, the elastomeric material is selected such that the elastic properties of the base 13 of the sock 1 1 are modified such that the modified base 13' of the sock 1 1 after the dipping, due to its composite structure comprising the fabric and the cured elastomeric substance on both opposite surfaces of the base 13 and in the mesh-openings, is stiffer, i.e. will be less elastic than the elastically stretchable fabric, preferably with a Young's modulus increased by 150%-850% compared to Young's modulus of the fabric, in the direction between the lateral sides 15 of the sock 1 1 . Since the mid-foot part 14 is not dipped, i.e. uncoated, this part will maintain the stretchable properties defined by the fabric of the sock 1 1 . It will be apparent to the person skilled in the art how to dimension the mesh- structure having regard to the viscosity of the relevant coating substance and further to adjust the time required for the dipping step in order to achieve a suitable migration and formation of the internal layer on the base 13. Normally, the overshoe 10 will then be finished, and is removed from the frame 25 before or after curing of the elastomeric substance.

However, in a further embodiment of the invention, the method may include an additional step comprising a second dipping of the sock 1 1 . For example, it may be desirable to have a second external coating layer having different characteristics than the first external coating layer. For example the second external coating may provide a second more durable, harder or softer coating layer of the overshoe 10. If several layers of coating are applied the elasticity of the modified base 13' resulting from the elasticity of the coating layers in combination, relative to the elasticity of the base 13 of the sock 1 1 , is of interest; hence, the appended claims are intended also to cover multiple dippings or coating applications, with different coating substances, when the end result is such that the elasticity is reduced, i.e. that the base 13' of the overshoe is stiffer than the base 13 of the sock.

In a further embodiment of the invention, the method may further comprise the step of providing the external coating 12 with an external friction pattern. This could for example be achieved by subjecting the external coating 12 to a patterned surface (not shown) such that an external friction pattern (not shown) is achieved at least on parts of the external coating 12. This step is advantageously carried out prior to or during the curing of the external coating layer 12. Alternatively, such external friction pattern may be achieved by post-curing machining or tooling.

The step of curing the coating substance may include cooling. Such cooling may include a cool airstream directed to the inside and/or outside of the overshoe 10 or it may involve rapid cooling such as temperature quenching.

The finished overshoe 10 will now be briefly discussed with reference to figs. 3 and 4a, where fig. 4a shows an embodiment where the coating layers, internal and external, are relatively thin such that the overshoe 10 assumes a flat configuration being at the same time foldable, eg. such that it may be kept in a trousers pocket until use, by the base being flexible. In contrast, the overshoe 10 of fig. 3 has coating layer(s) that are thicker such that the overshoe will assume and maintain the shown shape and configuration after removal from the frame 25. Shown in fig. 4b are wrinkles/pleats that may appear in the finished overshoe 10 after removal from the frame 25, depending on the manufacturing method.

As shown, the overshoe 10 comprises a sock 1 1 of an elastically stretchable fabric having a mesh-structure, and has a heel 16', a top 18' and opposite lateral parts 15' The top 18' includes a toe-part 17' and a mid-foot part 14. An opening 19 accessing the inside of the overshoe 10 is delimited by the heel 16', the mid-foot part 14 and the lateral parts 15', and is preferably elongated and preferably has a length L2' of at least 50%, preferably of between 50% and 65%, of the length L1 ' of the overshoe 10, the mid-foot part 14 being defined by the sock 1 1 . A flexible base 13' of the overshoe 1 1 , having modified properties compared to the base 13 of the sock 1 1 , is defined by the fabric of the sock 1 1 carrying on both sides a layer of a cured elastomeric material, the toe-part 17' carrying, preferably on the external side only, a layer of the aforementioned cured elastomeric material. The elastomeric material is preferably selected such that the flexible base 13' is stiffer than the base 13 of the sock, i.e. stiffer than the elastically stretchable fabric, preferably with a Young's modulus increased by 150%-850%, compared to Young's modulus of said fabric, cross-wise to the length of the overshoe 10. In this manner will the elastomeric substance serve to restrict or prevent any excessive deformation, such as by stretching, of the overshoe, while the non- coated portion, i.e. the mid-foot part 14, allows for a local widening of the overshoe 10 as the user introduces his shoe through the opening 19. After curing, the cured elastomeric material is present in opened-up portions of the fabric of the base 13', unless release of the sock 1 1 from the frame before curing is effective in squeezing out the elastomeric substance from the mesh- openings.

Preferably, the internal coating defines a uniform coating layer having a thickness, preferably a uniform or substantially uniform thickness, in the order of 0,1 mm - 0,5 mm, with the layer defined by the external coating, such as applied during a first dipping, having a thickness, preferably a uniform or substantially uniform thickness, in the order of 0,1 mm - 0,5 mm or in the order of more than 0,5 mm - 2 mm. What is achieved by the disclosed method is an overshoe which provides an internal and external friction by the formation of the cured elastomeric substance. The overshoe 10 thereby aids the user with increased safety and provides an improved user experience. What is further achieved by the disclosed method is an overshoe 10 which is economical to manufacture, making it suitable for disposal and yet it provides durability suitable for washing and re-use. Depending on the intended use of the overshoe 10, the materials used may be selected such that the overshoe 10 is optimized in terms of durability and/or cost of material to suit the specific use. For example, an overshoe 10 which is not intended for re-use but is rather disposed after usage may be comprised of less costly materials, provided that the resulting overshoe 10 fulfils the requirements of the intended use.

A pair of overshoes 10 according to the disclosed method may be used at least several times before the overshoe 10 is worn out. Accordingly, the overshoe 10 can be considered to be disposable because the relative cost can be quite low. The overshoe 10 can be made in various sizes, for example adult sizes for both men and women in small, medium, large and extra-large and similar sizes for children. The overshoe 10 may have various areas which are reinforced to provide greater rigidity and various other areas which may have a greater flexibility. The areas having relative flexibility and rigidity cooperate to ensure the protective sock 10 conform to the wearer's shoe without excessively slipping relative to the wearer's shoe or foot while being sufficiently flexible to permit the wearer to exercise a given activity.

The overshoe 10 can be used with many types of worker's shoes/boots. The precise extent to which the overshoe 10 covers the shoe may depend on various factors, for example the size and type of shoe and the particular design of the overshoe 10. The material used to make the protective sock may be black, transparent or opaque or may have a variety of colours.

In one embodiment, see fig. 5, the sock 1 1 also comprises a number of holes 23 arranged at least in the base 13 of the sock 1 1 . The holes 23 extend through the base 13 and form a fluid connection between the inside 21 of the sock 1 1 and the outside, as depicted in fig.5. Generally, the holes 23 may be created by any suitable method found in the art. In a preferred embodiment of the invention the holes 23 are formed in the sock 1 1 during the weaving process. During the dipping step the coating substance will migrate and penetrate the sock 1 1 through the holes 23, as well as through the open-up mesh-structure of the fabric. As the coating substance reaches the inside 21 of the sock 1 1 , the coating substance will accumulate into grip spots 20. The migration of coating substance from the outside 27 to the inside 21 will continue during the dipping step and consequently the size of the grip spots 20 will be determined partially by the time during which the sock 1 1 is surrounded by the coating substance 26. Some holes 23 may be located in portions of the sock 1 1 that are not stretched such that in those portions coating substance will only migrate into the inside of the sock 1 1 through the holes 23. Depending on the viscosity of the coating substance 26, the grip spots 20 may attain different shapes. A low viscosity may result in a spherical shape of the grip spots whereas a high viscosity may result in a more cylindrical shape of the grip spots since in the latter case, the grip spots are then shaped by the holes 20. The viscosity and the amount of time required for the dipping step may therefore be selected such that a preferable shape of the grip spots 20 is achieved. By way of example only, the toe-part 17' may have an extension L3' along the length of the overshoe 10 in the order of 10% of the total length L1 ' of the overshoe, while the mid-foot part 14 may have an extension L4' in the order of 25%, or at least 25%, thereof, with the extension L2' of the opening representing the remaining about 65% of the total length along the same longitudinal axis.

Figs. 6a-6c show yet another preferred embodiment of the invention. Here, the coating substance is not allowed to migrate into the interior the sock 1 1 during the aforementioned dipping, but only to migrate into the opened-up mesh structure. Rather, the sock 1 1 is provided with an elastomeric coating substance on the interior face or side of the base 13 of the sock 1 1 in a separate process step either before or after the dipping step. In this separate process coating substance may be applied, such as through screen printing or spraying, to form a continuous layer thereon or, as shown for the preferred embodiment, to form discrete areas 200 providing friction, such as in the form of dots or similar. Preferably, this separate process steps involves first inverting the sock 1 1 to apply the coating substance, and then re-inverting the sock 1 1 , after which the dipping step is performed on the sock 1 1 now carrying the coating substance on the inside, to form the external coating 210. In figs. 6a-6c shaded areas represent the portions of the sock 1 1 onto which no elastomeric substance has been applied while the white faces represent faces on the sock covered by the elastomeric substance. As will be understood from the foregoing the shaded areas are easily stretched; on the other hand the white areas are stiffer requiring a larger force for deformation. With this embodiment the base 13' of the overshoe will be more elastic compared to the embodiment where both sides of the sock 1 1 are covered fully by the elastomeric substance at the dipping step. With this preferably Young's modulus is increased by between 50% and 100%.

The term "comprising" as used in the claims does not exclude other elements or steps. The term "a" or "an" as used in the claims does not exclude a plurality. Where reference is made in the present application to internal and external surfaces this is normally meant to refer to surfaces facing a person's shoe and the outside, such as a building floor when worn, respectively. For the purpose of the possible filing of a divisional patent application the following alternative method of manufacture comprising a number of steps is briefly discussed: A first step comprises the providing of a flexible and stretchable sock where the sock may have a shape which is suitable for fitting on a shoe. The sock further comprises a number of purposely created through-going holes or perforations which are arranged at least on a sole layer of the sock in a predetermined pattern. The subsequent step includes the mounting the sock on to a last frame which stretches the sock into the intended size of the finished protective sock and/or provides the holes with sufficient size at predetermined locations. Following this step is a dipping step wherein the sock is immersed into a coating substance to the extent that at least an external sole surface of the sock is immersed and such that a coating is achieved at least on the external sole surface of the sock. As the dipping step is carried out, the coating substance is allowed to naturally migrate through the holes and into the inner space of the sock. In the openings of the holes in the inner space of the sock there will be accumulated coating substance which may also dispense out to the vicinity of the holes. Upon curing of the coating substance, these accumulations will form grip spots 20 on the internal sole surface of the sock and which protrudes into the inner space of the sock. Once the accumulations of coating substance have acquired desirable dimensions, the sock is retrieved from the dipping and cured. Upon curing, the resulting grip spots constitute an internal friction pattern on the internal sole surface of the sock. It is here preferable that the material of which the sock 11 is constituted is sufficiently dense knitted such that coating substance 26 does not substantially migrate through the knit, but rather through the holes 23, facilitating the formation of the grip spots 20. However, the material of which the sock 11 is constituted is sufficiently porous to allow absorption of the coating substance 26 to the extent that the resulting cured external coating 12 adheres to the sock 11. The formation of grip spots 20 is achieved by the provision of holes 23 which provide a path of low friction between the outer space 27 and inner space 21 enabling a natural migrating of coating substance 26 through the holes 23 to occur. If for example the material of the sock 11 were to be too loose knitted, a result may be that the coating substance 26 is absorbed uniformly over the surfaces of the sock 11 being exposed to coating substance 26 and the formation of distinct grip spots 20 would not be sufficiently facilitated. In one embodiment of the invention, the holes are dimensioned with regard to the viscosity of the coating substance in order to achieve appropriate formation of grip spots. In one embodiment of the invention, the grip spots have a preferred dimension of 3 - 8 mm in diameter and extending 1-5 mm from the internal sole surface into the inner space of the said sock.