Electric heating – Heating devices – With heating unit structure
Reexamination Certificate
1999-12-21
2001-04-10
Walberg, Teresa (Department: 3742)
Electric heating
Heating devices
With heating unit structure
C219S211000, C219S212000, C219S529000, C219S549000
Reexamination Certificate
active
06215111
ABSTRACT:
BACKGROUND OF THE INVENTION
Fabric heating/warming articles are known, e.g., in the form of electric blankets, heating and warming pads and mats, heated garments, and the like. Typically, these heating/warming articles consist of a fabric body defining one or a series of envelopes or tubular passageways into which electrical resistance heating wires or elements have been inserted. In some instances, the electric resistance heating wires are integrally incorporated into the fabric body during its formation, e.g. by weaving or knitting. Relatively flexible electric resistance heating wires or elements, e.g. in the form of a core of insulating material, e.g. yarn, about which is disposed an electrical conductive element, e.g. a helically wrapped metal wire or an extruded sheath of one or more layers of conductive plastic, have been incorporated directly into the woven or knitted structure of a fabric body.
SUMMARY OF THE INVENTION
According to one aspect of the invention, a method of forming a fabric article adapted to generate heat upon application of electrical power comprises the steps of: joining, in a continuous web, by a reverse plaiting circular knitting process, a stitch yarn and a loop yarn to form a fabric prebody, the stitch yarn forming a technical face of the fabric prebody and the loop yarn forming a technical back of the fabric prebody, the loop yarn forming in loops that overlay the stitch yarn at the technical face and the technical back of the fabric prebody, at spaced-apart intervals, incorporating into the fabric prebody as the stitch yarn an electrical resistance heating element, forming the fabric prebody into a fabric body, with the electrical resistance heating elements extending between opposite edge regions of the fabric body, and providing conductive elements for connecting the electrical resistance heating elements to a source of electrical power.
Preferred embodiments of the invention may include one or more the following additional steps: finishing at least one of the technical face and the technical back of the fabric body, in a manner avoiding damage to electrical conductivity of the electrical resistance heating elements, to form a fleece surface region, or finishing the technical face of the fabric body, in a manner to avoid damage to electrical conductivity of the electrical resistance heating elements, to form a first fleece surface region, and finishing the technical back of the fabric body in a manner to avoid damage to electrical conductivity of the electrical resistance heating elements to form a second fleece surface region; applying, directly to the continuous web, the conductive elements for connecting the electrical resistance heating elements to a source of electrical power; incorporating into the fabric body the electrical resistance heating element in the form of a conductive yarn comprising a core of insulating material and an electrical resistance heating filament disposed generally about the core, preferably, the conductive yarn further comprises a sheath material generally surrounding the electrical resistance heating filament and the core, preferably the sheath material is formed by wrapping the electrical resistance heating filament and the core with yarn; incorporating into the fabric prebody the electrical resistance heating element in the form of a conductive yarn comprising an electrical resistance heating filament; connecting the conductive element to a source of electric power and generating heat, the source of electric power comprising alternating current or direct current, e.g. in the form of a battery, which may be mounted to the fabric article; limiting formation of loops to a central region of the fabric prebody, the central region being spaced from edge regions in the fabric body, and providing the conductive elements for connecting the electrical resistance heating elements to a source of electrical power in the edge regions of the fabric body; and/or rendering the yarns of the fabric body hydrophilic or hydrophobic.
According to another aspect of the invention, a fabric article adapted to generate heat upon application of electrical power comprises a fabric body, a plurality of spaced apart electrical resistance heating elements incorporated into the fabric body and extending generally between opposite edge regions of the fabric body, and electrical conductor elements extending generally along the opposite edge regions of the fabric body and adapted to connect the plurality of spaced apart electrical resistance heating elements to a source of electrical power.
Preferred embodiments of this aspect of the invention may include one or more the following additional features. The electrical conductor elements are adapted for connecting the plurality of spaced-apart electrical resistance heating elements to a power source of alternating current or to a power source of direct current, e.g., a battery, which may be mounted to the fabric body. A series of at least three of the plurality of electrical resistance heating elements are symmetrically spaced and/or a series of at least three of the plurality of electrical resistance heating elements are asymmetrically spaced. The fabric body comprises a knitted body, e.g. a reverse plaited circular knitted, or other circular knitted (such as double knitted, single jersey knitted, two-end fleece knitted, three-end fleece knitted, terry knitted or double loop knitted), warp knitted or weft knitted body, or a woven body. The fabric body comprises hydrophilic or hydrophobic material. The fabric body has a technical face formed by a stitch yarn and a technical back formed by a loop yarn. The loop yarn forms loops that overlay the stitch yarn at the technical face and the technical back of the fabric prebody. The fabric prebody has loops formed only in a center region. The fabric body has fleece formed upon at least one, and preferably both, of the technical back and the technical face. The conductive yarn is a stitch yarn. The electrical conductor elements, at least in part, are applied as an electrically conductive paste or as an electrically conductive hot melt adhesive. The electrical conductor elements may comprise a conductive wire. The conductive yarn may preferably comprise a core of insulating material, an electrical resistance heating filament disposed generally about the core, and a sheath material generally surrounding the electrical resistance heating filament and the core. Preferably, the core comprises a yarn of synthetic material, e.g. polyester; the sheath material comprises yarn, e.g. of a synthetic material, such as polyester, wrapped about the electrical resistance heating filament and the core; and the electrical resistance heating filament comprises at least one metal filament, and preferably at least three metal filaments, wrapped helically about the core, the metal filament of the electrical resistance heating filament being formed of stainless steel. The electrical resistance heating element has electrical resistance in the range of about 0.1 ohm/cm to about 500 ohm/cm. In other embodiments of the conductive yarn, the core and/or the sheath material may be omitted. The fabric body comprises first and second fabric layers, and the plurality of spaced apart electrical resistance heating/warming elements incorporated into the fabric body are disposed generally between the first and second fabric layers. The fabric body comprises a double knit fabric body and the first and second fabric layers are joined, in face-to-face relationship, by interconnecting yarns, the plurality of spaced apart electrical resistance heating/warming elements incorporated into the fabric body being positioned and spaced apart by the interconnecting yarns and joined by the conductors in a parallel circuit. The first and second fabric layers are formed separately and joined, e.g by laminating or stitching, in face-to-face relationship, with the plurality of spaced apart electrical resistance heating/warming elements incorporated into the fabric body disposed therebetween. The plurality of
Rock Moshe
Sharma Vikram
Dahbour Fadi H.
Fish & Richardson P.C.
Malden Mills Industries Inc.
Walberg Teresa
LandOfFree
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