FIELD OF THE APPLICATION
The present application relates to footwear and, more particularly, to footwear with anti-puncture protection.
BACKGROUND OF THE ART
A function of some types of footwear is to protect the foot sole of a wearer against penetration of nails, screws or other similar sharp and rigid objects through the sole of such footwear when the wearer steps on such items. Accordingly, some items of footwear include a sole protection.
In some items of footwear, sole protection is provided by a steel or like puncture resistant material as an insert or embedded into the sole of the item of footwear. More recently, non-metallic multi-layer puncture resistant insole boards have also been developed, to provide more flexibility and insulation. According to some protective footwear standards, the steel or like puncture resistant material, where incorporated into the footwear, shall cover a minimal area of the sole, including the front and heel area, and shall be an integrated part of the footwear.
Referring to FIG. 1, an item of footwear with sole protection is illustrated at 1 in accordance with the prior art. The item of footwear 1 is generically shown as having two parts: the upper illustrated at 2 and the sole 3 secured to the upper 2. A junction 4 between the upper 2 and the sole 3 defines an inner perimeter 5 of the item of footwear 1. The sole 3 includes an insole structure 6, a midsole structure 7 and an outsole 8. The sole protection is provided by an insole board 9 made of a multi-layer puncture resistant laminated fabric.
In its relation with other components of the sole 3, the insole board 9 providing the anti-puncture features forms an assembly with generally uniform features along the sole 3. For example, the insole board 9 may be laminated to the midsole structure 7, or embedded in a polymer that is part of the insole structure 6 and/or of the midsole structure 7. There results an assembly with generally constant mechanical properties in terms of elasticity, hardness, resilience, conductibility, tensile strength. While such mechanical properties may be selected to enhance the protective properties of the sole 3, they may hamper the comfort of wearer of the item of footwear.
SUMMARY OF THE APPLICATION
It is therefore an aim of the present disclosure to provide a footwear with anti-puncture sole protection addressing issues associated with the prior art.
Therefore, in accordance with the present application, there is provided an item of footwear comprising: an upper adapted to receive a foot of the wearer; and a sole secured to the upper and adapted to be the interface between the wearer and the ground, the sole having a puncture-resistant membrane connected to the sole so as to provide puncture protection for the foot of the wearer, the puncture-resistant membrane having a puncture-resistant layer, a functional layer extending with and connected directly to the puncture-resistant layer and including at least a first functional layer portion and a second functional layer portion being side by side, the first functional layer portion having a first value for a given mechanical property, the second functional layer portion having a second value for said given mechanical property.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front cross-section view of an item of footwear with sole protection in accordance with the prior art;
FIG. 2 is a schematic longitudinal cross-section view of an item of footwear with an anti-puncture sole membrane in accordance with an aspect of the present disclosure;
FIG. 3 is a schematic longitudinal cross-section view of an item of footwear with an anti-puncture sole membrane in accordance with another aspect of the present disclosure;
FIG. 4 is a schematic longitudinal cross-section view of the anti-puncture sole membrane of an embodiment of the present disclosure;
FIG. 5 is a schematic longitudinal cross-section view of the anti-puncture sole membrane of another embodiment of the present disclosure;
FIG. 6 is a top schematic view of a configuration of the anti-puncture sole membrane; and
FIG. 7 is a top schematic view of another configuration of the anti-puncture sole membrane.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings and more particularly to FIG. 2, an item of footwear with anti-puncture sole membrane in accordance with one aspect of the present disclosure is shown at 10. The expression “anti-puncture” is used herein, but could also be known as puncture resistance, perforation resistance, anti-perforation, etc. For simplicity and to avoid redundancy, the expression “anti-puncture” will be used herein, and should be interpreted as meaning that the sole membrane complies with applicable standards in puncture resistance, some of which are enumerated below. The item of footwear is illustrated as being a work boot, but could also be any other type of footwear. The item of footwear 10 has two main parts: an upper illustrated at 20 and a sole 30 secured to the upper 20. A junction 40 between the upper 20 and the sole 30 defines an inner perimeter of the item of footwear 10. An anti-puncture sole membrane 50 may be embedded into the sole 30, or laid and attached to a remainder of the sole 30, as described hereinafter. Stated differently, the anti-puncture sole membrane 50 may be part of the sole 30. It is pointed out that the thickness of some of the layers is exaggerated in the figures (e.g., such as the thickness of the puncture resistant layers), to better illustrate the various layers.
The upper 20 is adapted to receive a foot of the wearer. The upper 20 may be composed of one or more layers of materials, such as, for example, leather, synthetic leather, nylon fabric, fabric, polymers, a combination of these materials, to name a few of the numerous materials that may be used to make up the upper 20. For example, FIGS. 2 and 3 show an inner liner layer 20A, for example made of leather, polyester with foam or felt or waterproof membrane (ePTFE). Also, a protective toe cap 20B may or may not be integrated into the upper 20. The protective toe cap 20B is for example made of metal or hard polymers and form a rigid shell that can withstand impacts. The expression “rigid” may entail a non-negligible resistance to elastic deformation, stiffness and/or structural integrity, in contrast to the surrounding panel material of the upper 20, such as leather. The protective toe cap 20B is shown as integrated into the upper 20, but may also be on the surface of the upper 20, as an example among others. The upper 20 has an outer layer, and may also comprises one or more of a backing reinforcement, a protective toe-cap, and/or an inner liner, among numerous other possibilities. The backing reinforcement may be provided as a laminated layer to reinforce the outer layer. Materials used for the backing reinforcement and the inner liner are those known in the art of footwear. The above-referred construction is one of many possible constructions for the item of footwear 10.
The protective toe-cap 20B is a protective component (e.g., steel toe-cap or composite toe-cap) defining a shell accommodating the toes of the wearer in the item of footwear 10. The toe-cap 20B protects the toes from impacts of objects falling against the toe region of the item of footwear 10. The inner liner 20A may be provided for enhanced comfort for the wearer to tolerate wearing the item of footwear 10 for longer periods, and/or for other functional reasons, such as sweat wicking, etc.
The upper 20 also comprises an insole 21, though the insole 21 may be absent or part of the sole 30. Although not shown, a removable sock liner may be within the foot-receiving cavity of the upper, and lies on a top surface of the insole 21. By way of example, the insole 21 may comprise various layers, using various materials such as cellulosic paper, synthetic non woven material, cushioning material such as urethane, latex and/or EVA, which provides wearing comfort of the item of footwear. Any other configuration is considered for the insole 21, with one or more layers.
The sole 30 may comprise a single layer, or may be an assembly of separate layers of different materials. These layers may be made of natural rubber or a synthetic material. As illustrated in FIG. 2, in accordance with one of numerous possible embodiments, the sole 30 may be made of two different layers: a midsole 31 and an outsole 32. Although the upper 20 of the item of footwear 10 as shown in FIG. 2 is depicted as including the insole 21, it is to be understood that other sole configurations are possible, for instance with the insole 21 being part of the sole 30. Also, many constructions of the sole 30 are possible, with one or more layers. For example, the insole 21 may be part of the sole 30 and may be connected directly to the outsole 32. The midsole 31 may be the portion of the sole 30 exposed in the inner cavity of the item of footwear 10, with or without a sock liner thereon.
The midsole 31 is connected to the upper 20. As shown in FIG. 2, the midsole 31 may optionally have two superimposed portions: the welt 31A and the midsole layer 31B. The expression “superimposed” may mean that the welt 31A projects upwardly from the midsole layer 31B. In an embodiment, the welt 31A and midsole layer 31B and integrally connected, and in another embodiment the integral connection is monolithic. The welt 31A may be a strip of leather, rubber, plastic or polyurethane that may be connected the upper 20. As shown in FIG. 2, the welt 31A may be connected by a direct injection molding process to the upper 20 to optionally provide a decorative stitch line, that may include a decorative thread. Consequently, in an embodiment, a direct-attach joint is formed by the welt 31A on the upper 20. Such direct-attach joint is without adhesive, i.e., adhesive-less, in that it is solely the curing of the material of the midsole 31 that connects the upper 20 and the midsole 31 together, for instance with the periphery or contour of the upper 20 embedded in the cured material of the midsole 31. As observed from FIG. 2, the midsole 31 may define an inner cavity 31C, i.e., closed inner cavity 31C. The inner cavity 31C may be the result of injection molding of the midsole 31 around the anti-puncture sole membrane 50, as described below. In such a case, the anti-puncture sole membrane 50 may be said to be part of the midsole 31, though it is contemplated to have the anti-puncture sole membrane 50 be part of the outsole 30, or be the direct relation between the outsole 30 and the upper 20, e.g., the anti-puncture membrane 50 being the midsole 31 as opposed to being part of the midsole 31.
The outsole 32 is adapted to be the interface between the wearer and the ground. The outsole 32 adheres to the midsole 31, for instance to the midsole layer 31B in FIG. 2, for instance by the use of an adhesive, or as a result of the direct injection molding process, in which case the surface between the midsole 31 and the outsole 32 is a direct-attach joint. Other configurations are possible for the sole 30, as it may consist of a single layer, with or without the welt 31A, without both a midsole 31 and outsole 32, with additional sole layers, etc.
It is observed from FIG. 2 that the inner perimeter 40 of the upper 20 is generally defined by the intersection between the upper 20 and the sole 30. The inner perimeter 40 may define the boundary delimiting the inner cavity of the upper 20 that receives the foot of the wearer. In other words, the inner perimeter 40, that defines the boundary delimiting the inner cavity of the upper 20, corresponds to the shoelast's edge.
Referring to FIGS. 4 and 5, the anti-puncture sole membrane 50 has an anti-puncture layer 51 which may be formed of a single material, or may be an assembly of materials, such as, for example steel or other metallic materials, high tensile strength synthetic, polymeric fibers, a combination of these material, for instance in a woven state and/or in multiple layers, and the like. The anti-puncture sole layer 51 uses the moniker “anti-puncture” as described above. The anti-puncture sole layer 51 is sized to match a footprint of a foot of the wearer, or extend beyond the footprint. Stated differently, the size of the anti-puncture sole layer 51 is sufficiently large to extend from end to end and side to side of the foot of a wearer in the upper 20. According to an embodiment, the anti-puncture sole layer 51 extends beyond the footprint of the last used to make the item of footwear 10. For example, the anti-puncture sole layer 51 extends to or beyond the inner perimeter 40, and this may be over the full periphery of the item of footwear 10, or a majority of the periphery of the item of footwear 10. The anti-puncture sole membrane 50 is said to be puncture resistant, in that its resistance to puncture is substantially greater per thickness unit than that of the material(s) of the sole 30. For instance, the anti-puncture layer 51 is made from one or more sublayers (e.g., up to seven sublayers) made of a high-tenacity tightly woven non-metallic textile (e.g., nylon woven fabric). In at least another embodiment, the anti-puncture layer 51 may have a single layer of a puncture resistant material that may withstand puncture forces. In accordance with an embodiment, the anti-puncture layer 51, regardless of its single-layer or multiple sub-layer construction, may withstand a force of at least 1200 Newton when tested according to protective footwear standard CAN/CSA Z195-14 clause 6.3.1. In still another embodiment, the anti-puncture layer 51 may comprise two sublayers that increase the puncture resistance of the anti-puncture sole membrane 50, for instance of at least 2500 Newton when tested according to protective footwear standard CAN/CSA Z195-14 clause 6.3.1. The puncture resistant layers may comply with such standards, or other standards like ASTM F2412/13, EN ISO 12568, or EN ISO 20344/45, among numerous other standards.
The anti-puncture layer 51 is connected to at least one functional layer 52, with the functional layer 52 having at least two different functional layer portions 52A and 52B, in order to have different values of mechanical properties as a function of the part of the foot anatomy. The anti-puncture layer 51 is said to be connected to the functional layer 52 in that main surfaces of the layers 51 and 52 are against one another, and may be adhered and/or interconnected in different manners. The layer portions of the functional layer 52 are respectively shown as a first functional layer portion 52A and a second functional layer portion 52B. In FIG. 5, a third functional layer portion 52C is also present. In FIG. 6, a fourth functional layer portion 52D is also present. In FIG. 7, and a fifth functional layer portion 52E is present. The functional layer portions 52A, 52B, 52C, 52D, and/or 52E (concurrently, functional layers 52) are side by side to define the functional layer 52, and are an integral part of the anti-puncture sole membrane 50 with the anti-puncture layer 51. The functional layer portions 52A, 52B, 52C, 52D, and/or 52E concurrently define the surface against which the anti-puncture layer 51 will lie in coplanar relation. For example, the functional layer 52 is molded with the anti-puncture layer 51. The layer portions 52A-52E may also be referred to as functional zones of the functional layer 52. According to an embodiment, the molding process is a two or three step molding process, depending on the number of functional layer and/or a variety of the functional layer. Therefore, the anti-puncture sole membrane 50 is an integral composite membrane, in that the various layers constituting it cannot be separated without a destroying force. According to an embodiment, the functional layer portions 52A-52E are made of polymers. For example, the functional layer 52 may be made of one or more of polyurethane (PU), thermoplastic polyurethane (TPU), rigid polyurethane (RPU), polyvinyl chloride (PVC), ethylene-vinyl acetate (EVA), rubber, latex, etc. For example, one of the functional layer portions 52A-52E may be made with one material or one construction of materials (e.g., composite), and another or other functional layer portions 52A-52E may be made of other materials or other constructions of materials (e.g., composite). As another example, two or more of the functional layer portions 52A-52E may be made of the same material, but with different densities for the two functional layer portions 52A-52E to offer different functional characteristics. For example, one functional layer portion 52A-52E may have a lower density to offer greater cushioning deformation, whereas another functional layer portion 52A-52E with the same material has a higher density to have a higher hardness than the lower density functional layer portion 52A-52E. Therefore, by having distinct functional layer portions or zones 52A-52E in the side by side arrangement of FIGS. 4 and 5, the anti-puncture sole membrane 50 has a variation of its mechanical properties in its different areas, which mechanical properties may include one or more of elasticity, hardness, resilience, conductibility, tensile strength, etc. Although the functional layer portions 52A-52E are shown separated from one another by joint lines J that are generally transverse to a longitudinal direction of the foot (front to rear), any shape of separation line is considered (a.k.a., anterior-posterior or antero-posterior direction). For example, a functional layer portion 52A-52E may be shaped to cover a single toe, or other anatomical parts.
Stated differently, a plane of the anti-puncture sole membrane 50 is shown in FIG. 6. Four distinct sub planes are shown, one for each of the functional layer portions, namely 52A, 52B, 52C and 52D, i.e., the sub planes together define the plane of the membrane 50, and the majority of the surface against which the anti-puncture membrane 51 may lie, the anti-puncture membrane 51 spanning over the layer portions 52A-52D. The function layer 52 as a whole, i.e., mosaicked from the layer portions 52A, 52B, etc. (if more than two) extends to or beyond the inner perimeter 40, and this may be over the full periphery of the item of footwear 10, or a majority of the periphery of the item of footwear 10. At least two of the functional layer portions, for example 52A and 52B, have a different value for a same mechanical property. For example, the functional layer portion 52A may have a lesser density than the adjacent functional layer portion 52B, for a same material (or a different material). As a consequence, the portion of the plane of the anti-puncture sole membrane 50 featuring the functional layer portion 52A may exhibit greater resilience/shock absorption (e.g., padding) than that of the portion of the plane of the anti-puncture sole membrane 50 featuring the functional layer portion 52B. Likewise, the portion of the plane of the anti-puncture sole membrane 50 featuring the functional layer portion 52B may exhibit greater hardness on the Duro scale than that of the portion of the plane of the anti-puncture sole membrane 50 featuring the functional layer portion 52A. For a same mechanical property (or properties), the adjacent functional layer portions 52A and 52B—and therefore adjacent plane portions along the plane of the anti-puncture sole membrane 50—have a different value (or different values).
According to an embodiment, the functional layer portion 52A is located at a front portion of the anti-puncture sole membrane 50, the front portion of the anti-puncture sole membrane 50 corresponding to a front portion of the item of footwear 10. The functional layer portion 52A is sized so as to extend below a front portion of the foot including the toes of a user, and at least a portion of the metatarsal bones: this includes the metatarsophalangeal joints (MTP joints) of the foot. The functional layer portion 52A may example extend below the toes and the ball of the foot. The functional layer portion 52A may be made of a material presenting relatively high flexibility (e.g., ethylene-vinyl acetate, flexible rubber, flexible polyurethane) in comparison to the other functional layer portions 52B-52D in the anti-puncture sole membrane 50. The flexibility of the functional layer portion 52A opposite the MTP joints have a lesser resistance to flexion at the MTP joints and may facilitate the walking movement of a user.
According to an embodiment, one of the functional layer portions 52 is made of a material with greater shock absorption properties. For example, such a functional layer portion has a lower density and therefore has an increased resilience, i.e., having a high modulus of elasticity, a large bandwidth of elastic deformation, and a high yield strength. The functional layer portion with relatively high shock absorption characteristics may be located in the anti-puncture sole membrane 50 to be aligned with pressure locations of the foot. For example, the functional layer 52 with shock absorption properties may be opposite to the hallux (i.e., the big toe) and/or opposite to the first metatarsal bone and/or opposite to the heel region of the foot.
According to an embodiment, a functional layer portion may have a greater density and increased rigidity, to provide a resistance to torsion. The functional layer portion with resistance to torsion may be located opposite to an arch of the foot. The functional layer portion with increased rigidity may be located opposite to more sensitive or nociceptive parts of the foot. For example, polyvinyl chloride (PVC) or some types of thermoplastic polyurethane (TPU) could provide an enhanced rigidity.
According to an embodiment, a functional layer portion may consist of material having a greater resistance to fatigue, so as to preserve the integrity of the anti-puncture sole membrane 50 over the life of the item of footwear 10. For example, some Thermoplastic polyurethane (TPU) like the Polyethylene terephthalate (PET) or nylon can maintain efficiency under fatigue.
The anti-puncture sole membrane 50 therefore has a unitary body in which the various layers 51 and 52 are interconnected so as not to be separable from one another. The anti-puncture layer 51 and functional layer 52 are assembled in any appropriate ways, such as overmolding in one or more steps, gluing/adhering, laminating, etc. In an embodiment, there results a uniform thickness for the anti-puncture sole membrane 50. In another embodiment, the anti-puncture sole membrane 50 has a continuous top surface and/or bottom surface, though the thickness may or may not vary in spite of the continuity. In another embodiment, the junction between the various layers 51 and 52 is seamless, in that there is no physical edge at the junction. In yet another embodiment, one or more of the various layers 51 and 52 has surface features to provide functionalities. For example, a series of parallel surface ribs may provide flexibility in one direction and rigidity in another. Also, the layers 51 and 52 are illustrated as being discrete layers. However, due to the porous nature of the anti-puncture layer 51, the material of the functional layers 52 may penetrate the pores of the anti-puncture layer 51. For example, if the functional layers 52 are injected polymers, the liquid or viscous state of the material of the functional layers 52 result in the anti-puncture layer 51 being embedded in the material of the functional layers 52.
The anti-puncture sole membrane 50 is shown as having the functional layers 52 defining the underlayer of the anti-puncture sole membrane 50, with the anti-puncture layer 51 defining the exposed surface of the anti-puncture sole membrane 50. However, the reverse arrangement may also be used, with the anti-puncture layer 51 oriented downwardly. Also, if the anti-puncture layer 51 is fully embedded in the material of the functional layers 52, the functional layers 52 may be apparent on both sides of the anti-puncture sole membrane 50, forming the closed inner cavity of the membrane 50 incorporating the layer 51 therein. The mechanical properties of the functional layers 52 may be exposed on both sides of the anti-puncture sole membrane 50 in such an arrangement, with the anti-puncture layer 51 providing puncture resistance on the majority if not all of the surface of the anti-puncture sole membrane 50.
The anti-puncture sole membrane 50 may be assembled into the item of footwear 10 in different ways. Referring to FIG. 2, the anti-puncture sole membrane 50 may be embedded into the sole 30. In such an embodiment, the anti-puncture sole membrane 50 may be a finished article then integrated into a remainder of the sole 30. As illustrated in FIG. 2, the anti-puncture sole membrane 50 is embedded into the inner cavity 31C of the midsole 31. For example, the item of footwear 10 of FIG. 2 may be manufactured by direct injection molding of the midsole 31. In such a case, the material of the midsole 31 forms a direct attach joint with the upper 20, with the outsole 32, and with the anti-puncture sole membrane 50. The material of the midsole 31 bonds to the underlayer of the anti-puncture sole membrane 50 when curing, forming a permanent joint, without the presence of adhesive.
Referring to FIG. 3, the anti-puncture sole membrane 50 is shown as being on top of the midsole 31, and as extending to the periphery of the sole 30. Stated differently, the anti-puncture sole membrane 50 forms part of the periphery of the sole 30, for example for part or all around the sole 30 (i.e., the full circumference). The anti-puncture sole membrane 50 in FIG. 3 interfaces the remainder of the sole 30 to the upper 20. According to an embodiment, the anti-puncture sole membrane 50 is molded into engagement with the upper 20 for a direct attach joint to be formed. This may be done in one or more steps. As alternatives, the anti-puncture sole membrane 50 may be stitched or sewn to the upper 20, and/or may be cemented to the upper 20. Moreover, although not shown, a Goodyear welt could be used for the assembly of the anti-puncture sole membrane 50 in FIG. 3 to a remainder of the sole 30 and to the upper 20.
According to an embodiment of FIG. 3, the outsole 32 is a molded component. To fabricate the item of footwear 10 of FIG. 3, the midsole 31 is injection molded so as to form a direct attach joint, without adhesive and with the connection being a result of the curing of the material of the midsole 31. The midsole 31 forms a direct attach joint with the outsole 32, and with the anti-puncture sole membrane 50.
Referring to FIG. 7, another embodiment of the anti-puncture sole membrane 50, with layer portions 52A-52E. The layer portions 52A and 52B are separated at an intersection J that is generally aligned with a length of the foot, as opposed to being transverse. As an example, the layer portion 52A, that will be aligned with the big toe when the item of footwear 10 is worn, has greater absorption capacity. The layer portion 52C, aligned with the metatarsal region of the foot when the item of footwear 10 is worn, may exhibit flexibility about axes transverse to a length of the foot, while being rigid against torsion in a direction parallel to the length of the foot. The layer portion 52C may have edges in common with three other functional layer portions, such as 52A, 52B and 52D. The layer portion 52D, aligned with the arch region of the foot when the item of footwear 10 is worn, may be selected for its rigidity about axes transverse to a length of the foot. The layer portion 52E, aligned with the hell region of the foot when the item of footwear 10 is worn, may be made of an absorbing material with resilience, and fatigue resistance.
In an embodiment, the anti-puncture sole membrane 50 has a thickness ranging from 2 mm to 12 mm from its top plane to its bottom plane (one of these planes shown in FIG. 6). While the expression “plane” is used, these planes may or may not be flat. In an embodiment, the thickness is constant along the membrane 50 (e.g., ±2 mm). By way of example, below is a table quantifying some of the characteristics mentioned above.
|
Flexibility (e.g., big
Rigidity
Resilience
|
Properties
toe, metatarsal)
(e.g., arch)
(e.g., heel)
|
|
Hardness (Shore A)
30-60
70-90
25-50
|
Young modulus
15-100
1000-4000
80-300
|
(MPa)
|
Ultimate tensile
3-50
45-100
>500
|
strengh (MPa)
|
Elongation (%)
200-800
20-80
50-300
|
|
Patent Application
20200163406
