Patent Application
20150040425
The invention relates to an air exhaust outsole for safety footwear haying a cushioning midsole with air ventilating channels to vent the interior of the upper, and a puncture resistant layer beneath the midsole, to provide a puncture resistant footwear with a ventilated upper.
The safe use of footwear in many working environments requires foot protection to avoid common injuries. Protection may include: puncture protection from sharp objects that puncture the sole of the footwear; impact and compression resistance for the toe area; metatarsal protection that reduces the chance of injury to the metatarsal bones at the top of the foot; electrically non-conductive properties which reduce hazards that may result from static electricity buildup, or reduce the possibility of ignition of explosives and volatile chemicals; and reduce the electric hazard risk of stepping on a live electrical wire.
In warehouse operations, manufacturing, heavy industry and construction, workers are required as a minimum to wear protective footwear and head protection, fall protection harnesses and other safety equipment. In general the employer provides, pays for or reimburses the workers for the costs of safety equipment. Footwear being personal and individually sized, is usually purchased by the worker and the costs are reimbursed by the employer. Accordingly workers exercise a high degree of personal choice over the comfort features and fashion when selecting safety footwear.
Safety shoes and boots in particular are widely used throughout workplaces to avoid easily preventable common foot injuries caused by stepping on objects that can puncture the sole of the footwear and injure the sole of the wearer's foot. Governments have established regulations for worker safety and footwear must comply with standard puncture resistance test such as ASTM F241305 (American Society for Testing and Materials) and CSA Z195 (Canadian Standards Association).
Modern protective footwear uses puncture resistant woven fiber layers bonded with rubber or resin. Woven fabric layers use high strength fibers, such as Kevlar™ fibers, spun into thread and tightly woven to replace metal plates that were used in the past to protect the sole of the wearer. Resilient plastic toe caps protect the wearer's toes.
Since footwear used in the workplace is often worn all day everyday, and since employers usually reimburse workers for the cost of safety footwear, comfort is a paramount concern in addition to safety and durability. Many safety footwear designs imitate the appearance and comfort of athletic shoes or dress shoes to enhance comfort as well as to comply with the wearer's fashion choices for their work clothing.
Many common designs for non-safety footwear and running shoes include ventilation of the upper to enhance wearing comfort by circulating air through the upper portion sometimes creating air movement through a pumping action as the wearer walks. Shoes for nurses for example often include superior cushioning, air bags, heel springs and ventilation for comfort due to the physical demands of that profession. Examples of ventilated footwear are described in U.S. Pat. No. 8,127,465 to Byrne et al and U.S. Pat. No. 4,078,321 to Famolare.
When wearing conventional safety footwear that include puncture protective soles, workers often experience discomfort since the protective sole prevents the escape of heat and moisture generated by the wearer's foot and motion. The protective sole may also be made of materials that conduct cold more readily than other conventional materials of the footwear. Metal plates in particular create discomfort since the metal readily conducts cold and heat and therefore modern safety footwear generally uses multiple puncture resistant woven fabric layers that reduce thermal conduction as well as electrical conduction.
Safety footwear are worn outdoors in all weather and are worn all day everyday in many environments, so discomfort from heat, cold, moisture, and water penetration is a serious concern. The protective sole in safety footwear is conventionally located. In the insole adjacent to the wearer's sole. Discomfort arises from the use of a puncture resistant protective layer that is relatively stiff, impedes air circulation, impedes heat dissipation, and impedes moisture transfer that prevents adequate drying of the insole adjacent the wearer's foot.
Accordingly, it is desirable to enhance the comfort of safety footwear while retaining the puncture protection provided by a puncture resistant layer.
Features that distinguish. the present invention from the background art will be apparent from review of the disclosure, drawings and description of the invention presented below.
The invention provides an air exhaust outsole, for safety footwear having an upper with an air permeable insole having a top insole surface for supporting a foot of the wearer, the air exhaust outsole comprising: a midsole, with a top midsole surface engaging a bottom insole surface of the upper, the midsole including at least one ventilation channel between a side midsole surface and the top midsole surface; a puncture resistant layer with a top surface bonded to a bottom midsole surface, the puncture resistant layer comprising a puncture resistant core bonded about at least a peripheral edge in a flexible coating; and a tread layer with a top surface bonded to a bottom surface of the puncture resistant layer; and a bottom tread surface.
In order that the invention may be readily understood, one embodiment of the invention is illustrated. by way of example in the accompanying drawings.
Further details of the invention and its advantages will be apparent from the detailed description included below.
As seen in
Therefore each of the four longitudinally spaced apart transverse ventilation channels 6 passes transversely through the midsole 1 and includes an inlet port 8 in the top insole surface 9 and a pair of outlet ports 7 in opposing left and right side midsole surfaces. The inlet 8 and two outlet ports 7 of each channel 6 are in communication via an internal transverse passage formed within the midsole 1.
In the example shown in
The midsole 1 provides a cushion immediately adjacent to the air permeable insole 5 of the upper 4. As a result, the wearer's sole is separated from the puncture resistant layer 2 by a ventilating and cushioning midsole 1 made of a flexible compressible material, for example injection molded ethylene vinyl acetate (IMEVA), commonly known as synthetic foam rubber. The wearer perceives substantially the same foot comfort as a ventilated and cushioned running shoe and does not perceive the discomfort caused by conventional puncture resistant layers that are generally positioned immediately adjacent or relatively close to the insole 5 of the upper 4.
As seen in
The midsole 1 in the heel area can also include a fluid filled bag (liquid or gas) or a compression spring molded into the foam structure of the midsole 1 in a manner similar to conventional running shoes. The top midsole surface 9 may also include an air/vapour permeable and liquid water resistant membrane such as Gortex™ covering the inlet port 8 to impede entrance of liquid water into the upper 4 from the ventilation channels 6.
As seen. in
The puncture resistant core 16 can be a puncture resistant woven fabric composite or and a sheet metal plate if desired. A puncture resistant woven fabric core 16 can be assembled from multiple layers of woven fabric bonded together with a resilient layer such as rubber or other adhesive compatible with the threads of the woven fabric. Use of a metal plate as a core 16 in some applications is adequate, however a woven fabric core 16 and/or the flexible coating 17 can be selected to be resistant to electric conduction and thermal conduction. The puncture resistant woven fabric core 16 can be made of threads spun from para-aramid synthetic fiber (Kevlar™) bonded in multiple layers of rubber as for example provided by the Italian manufacturer Lonzi Egisto S.p.a.
The outsole includes a tread layer 3 best seen in
The outsole described above provides a cushioning and ventilated midsole 1 adjacent the insole 5 and proximal to the wearer's foot sole for enhanced comfort, air circulation, heat dissipation and moisture venting. The location of the puncture resistant layer 2 enables the footwear to provide puncture resistance while avoiding problems that arise if a puncture resistant layer 2 is located close to the wearer's sole, namely, heat retention and moisture retention within the upper 4.
Although the above description relates to a specific preferred embodiment as presently contemplated by the inventors, it will be understood that the invention in its broad aspect includes mechanical and functional equivalents of the elements described herein.
