1. Field of Invention
This invention relates to a permanent external stabilizing element for work boots.
2. Discussion of Relevant Prior Art
A person working in construction or a similar field often spends extended periods of time standing or walking on surfaces that do not evenly or fully support the person's boot or shoe. This uneven support may translate into foot discomfort and fatigue. For example, while standing on the rung of a ladder briefly may not result in discomfort or fatigue, a few hours of standing on the rung of a ladder will likely result in extreme discomfort for the person due to localizing of pressure points on a small portion of the foot. A worker is forced to either endure the discomfort or continually shift position in an attempt to change the pressure points. As a result, the worker is less focused on the job at hand and less efficient.
One common answer to this problem is to provide a leather tuck board between the insole and the outsole or midsole (if present) of the work boot. However, this results in an unnecessarily heavy and stiff boot. Such a design makes walking in the boot difficult and more strenuous. Thus, while the tuck board addresses the problem when the wearer is standing, the tuck board impedes the wearer's ability to walk comfortably and easily while wearing such boots.
Some examples of external heel counters are found in athletic shoes which are designed to completely replace an internal shoe counter. For example, an existing design for an athletic shoe includes an external heel counter made of a resilient material for greater stability and comfort which is intended to completely replace an internal shoe counter and is confined to the heel area. Since this is an athletic shoe application and immediate energy rebound is desired, the material chosen is aimed at resiliency and energy return and not durability and toughness. Such materials would break down quickly and offer little resistance to damage in a working environment. As a result, these designs are ill-suited for work boots.
Another existing design reveals the use of a multi-layered sole on a hiking boot. The hiking boot has a reinforced element of semi-stiff plastic that forms one layer extending beneath the entire user's foot. It has two external stabilizing strips or arms that extend back to protect and support the heel. The heel portion of the layer does not connect with the stabilizing strips or arms. The heel is not fully connected to the reinforcement under the portion heel, but instead is only connected to the arch portion. Since this design is used in a hiking boot, it is aimed at adding stability while walking and allowing better return energy. As a result, these designs are also ill-suited for work boots.
It is an object of the invention to provide tough, durable, all-day support to a work boot.
It is also an object of the invention to provide support of the wearer's foot arch.
It is also an object of the invention to provide transverse rigidity to prevent or resist the transverse twisting of the foot between the heel and the ball of the foot.
It is also an object of the invention to provide counter rigidity for supporting the heel of the foot.
It is also an object of the invention to fulfill these objectives with a single structural element without adding unnecessary weight or significantly compromising flexibility of the work boot.
In response to the above identified objectives, the external stabilizing structure was developed.
The external stabilizing structure is a structural element for use in work boots and possibly other types of footwear. The external stabilizing structure comprises a molded footbed of stiff and resilient material that provides external support under the heel and arch of the wearer's foot. It also enhances the stability of the heel by enhancing the internal counter of the boot.
More specifically, the external stabilizing structure comprises a single piece of stiff and resilient hard-molded material that provides arch support, internal counter enhancement, increased transverse rigidity and counter rigidity to a work boot. The external stabilizing structure is permanently integrated between the upper and outsole or the midsole (if present) of a boot and is shaped to support the wearer's foot. An outsole of a boot is secured to the external stabilizing structure using an adhesive or cement or a stitched welt or a combination thereof. The external stabilizing structure is secured to the boot upper using adhesives and stitching.
By using a single piece of stiff and resilient hard-molded material, pressure points are defused throughout the length of the external stabilizing structure, thereby enhancing the wearer's comfort and stability while standing on ladder rungs, uneven or rocky surfaces and the like. But unlike a leather tuck board, the boot retains flexibility for comfortable walking and the weight of the external stabilizing structure is minimal, especially compared to a tuck board.
a is a top-down view the external stabilizing structure.
b is a front to back cross-sectional side-view of the external stabilizing structure.
a is an exterior side-view of the external stabilizing structure with the arch support.
b is a bottom-up view of the external stabilizing structure.
a is a side to side cross-sectional view of the external stabilizing structure with the arch support.
b is a side to side cross-sectional view of the external stabilizing structure.
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The molded footbed (14) of the external stabilizing structure (10) has a top plane (22) and a bottom plane (24) and extends under the heel and arch of a wearer's foot. The molded material forming the external stabilizing structure may be molded plastic such as TPU (thermo plastic urethane), PU (polyurethane), PVC (polyvinylchloride), TPR (thermal plastic rubber), and ABS (acrylonitrile butadiene styrene), or rubber. In addition, combinations of materials, such as cork, rubber and laminates, may be used. The thickness and shape of the molded footbed (14) may vary to enhance the overall performance of the external stabilizing structure (10) both in terms of comfort and support.
The heel support structure (16) is an integral part of the external stabilizing structure (10). It provides exterior reinforcement to the internal counter of the boot upper. The heel support structure (16) is located behind and below the heel region of the boot upper and cups the entire heel of the wearer, providing additional rigidity and support beneath and behind the wearer's foot. The heel support structure (16) also protects the rear heel of the boot, which is prone to be damaged due to contact with hard and rough materials, operating machines, and other boots.
An optional, but preferred, welt deck extension (12) borders the bottom of the external stabilizing structure (10). The welt deck extension is where the outsole attaches to the boot outsole or midsole (if present). The boot outsole is the part of the completed boot that contacts the ground. If present, the boot midsole is located between the outsole and the external stabilizing structure (10) attached to the upper. The outsole is secured to the bottom of the external stabilizing structure (10) using either an adhesive or cement welt or a stitched welt, which is sewn through the welt deck extension (12), or a combination thereof. Stitched welts placed through the welt deck extension (12) are preferred for easier outsole replacement, which is an important feature for a work boot.
A re-enforcing strengthening channel (18) provides a border of thicker material along the top exposed edge of the external stabilizing structure (10). The re-enforcing strengthening channel (18) enhances the overall strength of the external stabilizing structure (10) and increases the durability of the external stabilizing structure (10). It also serves an aesthetic roll by blending with design elements often found on work boots. An optional name plate depression (20) may also be provided on the exterior surface of the heel support structure (16) if it is desirable to allow placement of the brand name of the manufacturer on the heel of the boot.
Referring now to
Unlike a standard boot without the external stabilizing structure (10), a boot with the external stabilizing structure (10) better distributes uneven pressure created by an uneven surface across the molded footbed (14) and the heel support structure (16) to prevent discomfort or fatigue at any single point in the wearer's foot. Furthermore, the support provided to the heel is very comfortable because the external stabilizing structure (10) provides a one-piece molded heel cup that evenly supports the heel from the bottom and back. Without the external stabilizing structure (10) the wearer's foot muscles would need to act to counteract the uneven support. The external stabilizing structure (10), as a result, increases the wearer's comfort and decreases fatigue.
a and 2b are aligned to show the relative positions of features of the external stabilizing structure (10) from a top-down view (
In a preferred embodiment, the external stabilizing structure (10) is attached beneath a boot upper by a combination of adhesive and stitching. Referring now to
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While the external stabilizing structure (10) may be composed of any suitable stiff and resilient material, TPU (thermo plastic urethane) is preferred if the outsole is stitched to external stabilizing structure (10), but any material demonstrating the same or similar durability, flexibility and strength characteristics may be chosen. If the outsole is secured with adhesive cement, then the external stabilizing structure (10) is preferably formed from carbon fiber composite.
In manufacturing any particular external stabilizing structure for use in a shoe or boot, the dimensions will vary in proportion to standard shoe and boot sizing parameters. As referenced below, a “last” or rough model of the human foot is used to assist in manufacturing the external stabilizing structure. For example, the external stabilizing structure for use in a standard men's size 9 work boot will have a length between 170 mm to 180 mm. During construction of a work boot containing the external stabilizing structure, the molded footbed of the external stabilizing structure ends 5 mm short of the ball of the last on a standard men's size 9 work boot. This leaves the ball of the last unsupported by the external stabilizing structure and free to flex. Again, on a standard men's size 9 work boot, the beginning of the arch support is positioned 65 mm to 75 mm from the heel, the center of the arch support is positioned 105 mm to 120 mm from the heel, and the end of the arch support is positioned 160 mm to 175 mm from the heel. These dimensions and ranges are important because the external stabilizing structure channels energy to flex at the ball of the boot and not at the heel breast which is where boots and shoes without the support will tend to flex in addition to at the ball of the foot. In addition to the shoe or boot size, the final dimensions of any external stabilizing structure manufactured will vary due to other elements, such as insulation which would change the overall size of the boot.
In manufacturing any particular external stabilizing structure, the molded footbed of the external stabilizing structure is contoured, in part, based on the last used in designing the boot. As a result, the contour of the molded footbed will vary in order to address changes in the last that are the result of different heel heights. When constructing boots, the height of the heel determines the application of the boot. A standard work boot is built to have a ⅝ inch heel height. In contrast, a cowboy boot has a 2 inch heel to hold the boot in the stirrup and a logger boot has a 2½ inch heel to hold onto the spike when climbing trees. This heel height, in part, determines the shape of the bottom of the last. Therefore, the exact contour of the molded footbed varies depending, at least in part, on the function of the boot and the related heel height.
The external stabilizing structure (10) provides additional material to support the wearer's arch by enhancing the arch support present in the upper. However, the thickness of the material on the external stabilizing structure (10) varies in other areas as well. The varying thickness supports the natural contours of the human foot. The bone structure in the foot is not flat, but instead is shaped to naturally absorb the forces encountered when the foot impacts the ground. The external stabilizing structure (10) cradles the foot. By cradling the foot, the external stabilizing structure (10) supports, instead of cushions, the foot and ankle so they are positioned to naturally absorb the impact of a step.
In addition to the direct advantages of the external stabilizing structure (10), the external stabilizing structure (10) also offers manufacturing advantages. First, since the external stabilizing structure (10) is a single piece of molded plastic, it can be integrated into footwear much faster than placing support and protection in the arch support and heel area separately, saving labor costs. Second, it is faster and less costly to utilize the external stabilizing structure (10) than to utilize a leather tuck, which is commonly used to attempt to address some of the problems that the external stabilizing structure (10) solves. Finally, since the external stabilizing structure (10) can be integrated into most footwear without any or significant reworking of existing designs, it offers a less costly way to address support problems that may come up after a shoe or boot has already been designed and sold.
The foregoing descriptions and figures of the invention are explanatory and illustrative only, and various changes and details may be made within the scope of the appended claims without departing from the true spirit of the invention