Classifications

• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B7/00—Footwear with health or hygienic arrangements
  • A43B7/36—Footwear with health or hygienic arrangements with earthing or grounding means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
  • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed

Definitions

• the present invention relates to outsoles for footwear, which prevent electrostatic discharges (ESD) from persons wearing the footwear to devices being handled, and to methods for manufacturing such outsoles .
• ESD electrostatic discharges
• Static electricity discharges from a person to an electrostatic sensitive device or material being handled is often sufficient to damage the device.
• an electrostatic sensitive device or material being handled e.g. an integrated circuit or an electronic device
• factory workers can generate electrostatic potentials in excess of 20,000 volts simply by walking on a factory floor.
• the friction between the sole of the footwear and the floor material causes a high voltage potential to develop on the worker. If the worker comes into close proximity to an electrostatic sensitive device, the charged worker can cause a discharge to the device and consequently damage it.
• the first such device is a dissipative strap which is placed around the user's ankle or in the shoe and which remains in contact with the heel, see e.g. US 5,653,047.
• the charge is substantially neutralized.
• Some of the problems with this device include user's failure to properly attach the device and failure of electrical component due to irregular walking, since the grounding device may not work properly until the heel comes into sufficient contact with the floor.
• a second type of device is a static dissipative shoe. Typically, these shoes fall in the electrostatic discharge range of 10 6 to 10 9 ohms/sq.
• the outsole of such shoe has chemical substances blended with the plastic material of the outsole to create a static dissipative resistance. Such shoe may have a limited use due to the relatively high resistance and further the chemical substance may limit the useful life of the device .
• US 5,653,047 discloses a shoe comprising conductive plugs which are located in the toe region of the outsole of the shoe, and which protrude slightly above the upper surface of the outsole and below the lower surface of the outsole in order to provide stable contact with both the ground and a conductive layer on the inside of the shoe.
• Problems and drawbacks associated with the shoe of US 5,653,047 may include (i) complex and expensive manufacture, ( ⁇ ) risk of occurrence of gaps or pockets between the conductive plugs and the outsole, in which dirt and moisture may be collected, (iii) inconveniences when using the shoe if the conductive plugs protrude too much and/or unreliable electric contact if the conductive plugs protrude too little, (iv) risk of unreliable operation after some time's use due to wearing down of the conductive plugs, and (v) a complicated structure at the upper end of the conductive plugs .
• a main object of the present invention is therefore to provide an outsole for a footwear, which prevents electrostatic discharges (ESD) from a person wearing the footwear to a device being handled, and by which the above problems and drawbacks of the prior art can be .avoided or at least alleviated.
• a further object of the invention is to provide such an outsole, which has an improved reliability and resistance against wear and tear.
• a still further object of the invention is to provide a method for manufacturing an outsole for a footwear, which prevents damaging of devices caused by electrostatic discharges, and which fulfils the above objects.
• Fig. 1 illustrates a shoe having an outsole in accordance with an embodiment of the present invention.
• Fig. 2 is a cross sectional view of the shoe according to Fig. 1.
• Fig. 3 is an enlarged part of Fig. 2.
• Figs. 4-6 are each a cross sectional view of a shoe having an outsole in accordance with an alternative embodiment of the invention.
• Figs . 1 and 2 show a shoe or footwear having an outsole in accordance with an embodiment of the invention.
• the shoe has an upper part 1 which is open at an upper end portion thereof and, if desired, can be provided with a protective cap (not explicitly shown) of conventional type.
• Reference numeral 2 indicates the outsole, and reference numeral 3 indicates an insole made of a comfort-improving material.
• the outsole 2 comprises, according to the invention, an electrically conductive connection from an upper surface 2a of the outsole to a lower surface 2b of the outsole in the form of a plurality of electrically conductive fibers 4.
• the electrically conductive fibers may be of carbon, of a metal, of an electrically conductive polymer material, or of virtually any other kind of electrically conductive material.
• the electrically conductive fibers 4 are preferably molded integrally in a hardenable flexible, material 5, e.g. polyurethane material, of the outsole 2, so that the electrically conductive fibers 4 maintain the relative positions they adopt in connection with the molding process.
• the electrically conductive fibers 4 are embedded in a hardenable binder, which at surrounds at least portions of the electrically conductive fibers 4, and, in a hardened state, fixates the electrically conductive fibers 4 in their positions relative one another.
• the electrically conductive fibers 4 are arranged randomly in relation to one another in a non-woven condition, so that they do not form an arranged fibrous structure like a woven fabric or equivalent.
• the electrically conductive fibers 4 are preferably distributed directly in the mold in a random pattern.
• the electrically conductive fibers 4 may be present throughout the entire outsole 2 or a major portion thereof, or they may be present at one or several separate lateral portions of the outsole 2.
• the length of the electrically conductive fibers 4 may be longer than a thickness of the outsole 2 of the shoe.
• the electrically conductive fibers 4 provide a plurality of electrically conductive paths from the upper surface 2a of the outsole 2 to the lower surface 2b of the outsole 2.
• a more reliable low-resistivity electric connection is obtained.
• each of the electrically conductive fibers 4 is fixated to the insole 3 (or to the upper surface 2a of the outsole 2 or to any other layer in contact with the outsole 2) at a respective end thereof and the length of the electrically conductive fibers 4 are longer than the thickness of the outsole 2 of the shoe.
• the electrically conductive fibers 4 are arranged so that they each extend from the upper surface 2a of the outsole 2 to the lower surface 2b of the outsole 2 to thereby provide for multiple electric paths through the outsole.
• Fig. 4 the electrically conductive fibers 4 are distributed evenly throughout the outsole to obtain a hair bristle brush like appearance of the electrically conductive fibers 4 even though the electrically conductive fibers 4 are embedded in the flexible material 5 of the outsole 2.
• Fig. 5 a similar embodiment is illustrated.
• the electrically conductive fibers 4 are present at several separate lateral portions of the outsole 2.
• the electrically conductive fibers 4 can be felted together. Felting means that the electrically conductive fibers 4 become hooked together and attached to one another in a non-woven condition.
• Such a felted or tangled layer can, even if it is thin, be handled as a unit during the procedure of manufacturing the outsole 2. Other methods of holding the fibers together which facilitate their handling can also be used.
• Fig. 6 an embodiment of the invention, which makes use of such felted layers in non-woven condition, is illustrated.
• the embodiment comprises a plurality of felted layers 4, wherein each layer comprises electrically conductive fibrous material that provide an electrically conductive connection from the upper surface 2a of the outsole 2 to the lower surface of the outsole 2b.
• the felted layers 4 are preferably arranged substantially vertically in the outsole 2 at multiple lateral locations of the outsole. Alternatively, only one felted layer comprising electrically conductive fibrous material is provided in the outsole 2.
• the plurality of electrically conductive fibers may include one or several woven layers of electrically conductive fibers in the outsole, possibly arranged vertically in the outsole.
• Each of the felted or woven layers may be provided as a double, triple, or multilayer.
• the plurality of electrically conductive fibers may be stitched or knitted into a fiber based system, matrix, or layer made e.g. of a polymer material, which is then in turn molded integrally in the hardenable flexible material of the outsole.
• the electrically conductive fibers 4 may comprise fibers of a linear density of fiber mass of between about 0.5 and about 5 denier, and/or fibers of different linear densities of fiber mass.
• the electrically conductive fibers 4 may be provided in lengths of between about 20 mm and about 100 mm.
• the above outsole provides an excellent ESD protection function.
• a footwear with the above outsole will prevent electrostatic discharges from a person wearing the footwear to a device being handled. Further, the footwear reduces the risk for a person wearing the footwear of getting an electric shock due to an electrostatic discharge.
• outsole of the above kind may be provided with a flexible anti-nail protective layer arranged in between the insole 3 and the outsole 2 or within the outsole 2 as being described in our pending US patent application published under No. US-2006-0265909-A1.
• the various embodiments of the outsole described above may be combined to form yet further embodiments of the invention.
• the plurality of electrically conductive fibers may be present in a plurality of the described structures or systems depicted above.
• embodiments may be manufactured in a plurality of manners according to the invention.
• an outsole 2 for a shoe which prevents damage caused by electrostatic discharges, is manufactured by (i) arranging or attaching electrically conductive fibers 4 at the under side of an insole 3 of the shoe, which in turn is attached to an upper part 1 of the shoe, and (ii) molding flexible material 5 to the insole 3 and optionally to the upper part 1 to thereby fixate the electrically conductive fibers 4 in the flexible material 5 and thus form the outsole 2.
• the electrically conductive fibers 4 have to extend through the entire outsole 2 to provide for an electrically conductive connection through the outsole.
• the electrically conductive fibers 4 may be arranged in any manner disclosed in the present description.
• an outsole for a shoe which prevents damage caused by electrostatic discharges, is manufactured by (i) arranging or attaching electrically conductive fibers at the under side of an upper part of the shoe, which is closed at a lower end portion thereof, and (ii) molding flexible material to the upper part of the shoe to thereby fixate the electrically conductive fibers in the flexible material and thus form the outsole 2.
• an outsole for a shoe which prevents damage caused by electrostatic discharges, is manufactured by (i) arranging electrically conductive fibers in a mold, and (ii) molding the outsole by feeding flexible material to the mold and harden the flexible material to thereby fixate the electrically conductive fibers in the flexible material of the outsole.
• the electrically conductive fibers are molded so that an electrically conductive connection from an upper surface of the outsole to a lower surface of the outsole is obtained.
• electrically conductive fibers are protruding from the upper and the lower surfaces of the outsole.
• the outsole can in a later stage be attached to an upper part of a shoe, thus forming an entire shoe, which prevents electrostatic discharges from a person wearing the footwear to a device being handled.

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• Health & Medical Sciences (AREA)
• Epidemiology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

Country Status (6)

Families Citing this family (3)

Citations (1)

Family Cites Families (5)

• 2007
  • 2007-02-28 SE SE0700490A patent/SE531804C2/sv not_active IP Right Cessation
• 2008
  • 2008-02-26 CA CA002679061A patent/CA2679061A1/en not_active Abandoned
  • 2008-02-26 WO PCT/SE2008/000155 patent/WO2008105709A1/en active Application Filing
  • 2008-02-26 US US12/449,826 patent/US20100031537A1/en not_active Abandoned
  • 2008-02-26 CN CN2008800064735A patent/CN101677648B/zh not_active Expired - Fee Related
  • 2008-02-26 EP EP08724098A patent/EP2114186A1/en not_active Withdrawn

Patent Citations (1)

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