CA1200051A - Electrostatic charge suppressing garments - Google Patents

Abstract

ABSTRACT OF DISCLOSURE
Garments for suppressing accumulation of electrostatic charges and including fabric formed of yarns knit together with conductive strands. The garments described may engage various body portions. The fabrics used may be of plain or pile knit constructions.

Description

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ELECTPOSTATIC CHA~E S~PPi~ESSli~iG G~Ri~ENTS

Eicld_and_t'~clc~round_of_lnv~nli_n This invention relates to garments which suppress accumulation of electrostatic charges on the body of a person wearing the garmcn-t.
Electrostatic charges accumulating on the bodie5 of persons have been recognized as presenting ha~ards either to the persons or to industrial processes being conducted in the presence of such persons. ey way of examples, surgeons and nurses in operating theaters are from time to time in the presence of explosive or 1 n potentially explosive atmospheres, in which a sparlc such as can result from discharge of accumulated static presents a signifTcant danger. For that reason, It has been proposed to provide such persons with special protective garments intended to suppress such charges.
Persons employed in "clean rooms" for the production of mlcroclrcult components such as chips may, due to electrostatic charges, either destroy components under productTon or introduce contaminants such as dust.
For those reasons, it has been proposed to provide special atmospher~s within such rooms in an attampt to suppress electrostatic charges. Persons employed in operations conducted near or adjacent sources of electrostatic charges such as power lines may, due to electrostatlc charges, be exposed to the possibility of arcing over, or electrical discharge -i-hrough their . ': ~ ! ` . . ' 5~

bodies. As will be appreciated, in all such instances it is desirable for the protection of either the persons or the process that electrostatic charge accumulation be suppressed.
Brief Description of Invention The invention provides a garment for suppressing accumu-lation of electrostatic charges and comprising a body engaging member and a knit fabric forming at least a portion of said body engaging member, said knit fabric being formed oE yarn knitted into courses and wales and including an electrically conductive strand knitted with the yarn, wherein said yarn is knit into stitches defining a ground and stitches defining loop pile extending from the ground, and further wherein said conductive strand is knit with stitches defining loop pile.
Garments are contemplated for engaging a number of different body portions such as the torso, a foot, a leg, or a hand.
As will be pointed out more fully hereinafter, specific garments may be selected for particular applications.
Brief Description of Drawings Some of the objects of the invention having been stated, other objects will appear as the é~i .~ ,;

.' ~2~S~l description proceeds, when -i-aken in connection with the accompanying drawings~ in which:
Figure 1 is a prespectlve view of a sandal embodylng the present inventton;
Figure 2 is a sectional view through a strap of the sandal of Figure 1, taken generally along the line

2-2 in that Flgure;
Flgure 3 is a sectional view simllar to Flgure 2, taken genarally along llne 3-3 through the sole of the sandal In Figure l;
Figure 4 is a perspectTve vtew of a woman's shoe embodying the present invention;
Flgures 5 and 6 are sectlonal vlews through the shoe of Flgure 4, respectlvely taken generally along the ~-lInes 5-5 and 6-6 Tn that Figure;
FTgure 7 Is a perspective view of a man's shoe embodylng the present Inventlon;
Flgure 8 Ts a sectlonal vtew slmilar to Flgures 3 and 5, taken generally along the llne 8-8 In Figure 7;
~ Figure 9 is a perspective view of an overshoe, : : foot cover or bootie embodying the present Tnvention; `
; FTgure 10 Is a perspectlve, somewhat schematic, ~: vlew of a fabric as used In the garments of Figures through 9;
: 25 ~ Ftgure 11 Is a schematic, enlarged perspective vtew of the fabrlc of Ftgure 10;
Ftgures 12 and 13 are enlarged perspective vtews slmtlar to Figure 11, respectively tal<en from the pTle : ~ :

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face and the ground face of th~ fabric of Ftgure 10;
Figure 14 ts an elevatlon view of a hose embodying the present invention;
Figure 15 ts a schematic, enlarged elevation view of a portion of the hose of Figure 14, taken generally along -i-he line 15-15 in that Figure;
Flgure 16 is an elevation view, partly schematically broken away to represent fabric constructlon, of a legwarmer in accordance with the present Inventton;
Figure 17 Is a view similar to Figure 16, showing a low rlse athletic sock embodying the present inventlon;
~ Flgure 18 is a perspective vTew, partly ; 15 schematlcally broken away, of a mitt0n embodying the present Inventlon;
Flgure 19 Is a sectional view taken generally along the line 19-19 in Figure 18; and ~; Figure 20 is a view similar to Figure 18, showing a:glove embodying the present invention.
Detailed DQscri4tl_n ~ In~ention While the present invention will be described more fuiiy hereinafter with reference to the accompanying drawings, in which a preferred embodiment of the present ::
: : 25: invention is shown, it ts to be understood at the outset :~ : of the:description which follows that persons of skill :: in tne appropriate arts may modify the invention here : ~:
~ described while still achleving the favorable results of :: :

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this invention. Accordingly, tha description which follo~s is to be understood as being a broad, teaching disclosure directed to persons of skill in the appropriate arts, and not as limiting upon the present invention.
Referring now more particularly -to the accompanying drawings, the present invention is shown embodied in a number of different garments for suppresslng accumulation of electrostatic charges, each of which comprises a body engaging member. In Figures 1 through 9, to which a-ttention wTII first be direc-ted, the body engaging member is in the form of a foot engaging member, whlch may be a sandal (Figures through 3), a woman~s shoe (Figures 4 through 6), a man's shoe (Figures 7 and 8), or an overshoe, footcover or bootie (Figure 9). Persons skilled in tha arts relating to garments of this general class will be able to recognize other types of foot engaging garments which ; may embody the present invention~ and it is contemplated that any such garmen-t may use the present invention. It is also contempla-ted that -the word l'garment" will here be understood as beTng used with reference to any articl~ of clothing or object which covers or engages any portion of a person's body.
rhe sandal of Flgure 1, generally designat0d at 30, has a sole portton 31 and straps 32, 3~, 35; all of whlch engage or contact the body of a wearer of the sandal 30. In accordance with the present invention, a 12~5~

knlt fabric generally indicated at 3~ In Figures 2 and 3 forms at least a portlon of the body 0ngaging members of the sandal 30. The knit fabrTc 36 has particular characteristics as pointed out more fully hereTnafter, such that electrostatic charges otherwTse possibly accumulat1ng on the body of the wearer of the sandal 31~
are dTscharged or dissipated. In particular, the knit fabrlc 36 is formed o~ yarn, preferably a synthetic yarn such as polyes~er, knTtted into courses and wales. An electrlcally conductive strand Is knitted with the yarn, g7v1ng the fabrlc 36 its particular characteristTcs. The yarn may be Icnit with a plaTn knit construction or may be knlt with a plle knlt constructTon. In the latter Tnstance, the conductlve strand may be knit wlth stltches formlng the ground or base fabrlc from whtch the plle extends, or may be knit wlth stltches forming loop pile. Where a pile fabrlc Is used, placement of the conductlve strand with the pile loops ~ay contrTbute to ~ maximlzatlon of the desired effects, and therefore may be preferable.
The conductive strand used preferably Is a synthetic monofllament yarn having electrIcally conductlve characteristi C5 due to the inclusion of conductlve materlals Tn the strand as extruded. Such 25 ~strands are available commerclally in the form of mono~fllament nylon havlng carbon black extruded as a bicomponent. Other forms of such conductive strands will be known to persons of approprTate skill Tn the ,, :

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appllcable arts.
The woman~s shoe of Ftgures 4 through 6, generally indicated there at 38~ may have the fabric 36 present in an innerlining (Figure 5) and in a strap lining (Figure 6). Similarly~ the man's shoe of Figures 7 and 8, generally indicated there at 39, may have the fabric present in an tnneriining (Flgure ~). In each instance, the presence of the fabric accompllshes the dlssipatton or discharge of elecirostatic charges otherwlse possibly accumulating on the body of the wearer of the shoe.
Lastly, wTth respect to the illustrated footwear, the fabrlc 36 may be fabrTcated tnto an overshoe, footcover or bootle as generally Indicated at 40 in Figure 9. Such a footcover is particularly desirable for envlronments In whlch persons may ordlnarlly expect to wear conventlonal shoes, and yet statlc suppresslon Is needed, as In an operatlng room or a clean room.
A fabrlc useful In the footwear constructlons Illustrated and descrlbed to thls polnt Is shown In 20 ~Flgures 10 through 13. As there shown, the conductive strands present in the fabric preferably are arranged, due to the knlttlng process, In courses or bands In the ~abric. ~y spaclng such courses, a greater dlsslpatlon effect Is achleved through the provlsion of more clearly defIned pathways for the electrostatlc charges to follow ~In flowlng from the wearer's body. The fabrlc ~schematlcally Indlcated In Flgure 10 may be a plle fabrlc, and may be constructed as shown more :

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spectfically in Figures 11 through 13. There, a conductlve strand is indicated at 41, while other yarns knitted with the conductlve strand are indicated at 42.
FTgure 11 is included to indicate a typical stltch construction, while Ftgures 12 and 13 are intended to present an appearance more nearly approaching the actual fabric as l<nlt. Persons skllled in the arts of knittTng wlll be able to determine other knit fabric constructions through whlch the advantages of the present tnvention may be realized.
Garments embodying the present invention and constructed to engage a leg are also contemplated by the present tnventlon, as shown in Ftgures 14 through 17. As ; wlll be recognized by persons skllled in the appltcable garment arts, such garments are oiten constructed of kntt fabrlcs, and lend themselves admtrably to applIcatlons of the present inventlon. In such garments as the hose or half-hose illustrated in Figures 1~ and at 44, the conductive strand or strands may be Introduced into bands or courses 45 interspersed with bands or courses 46 of other synthetlc or natural yarns whlch are not conductive. As a consequence, static otherwlse posstbly accumulattng on the body or clothing i of a wearer of the hose 44 wtll be dlscharged to ground 25~ or dtsstpated, so as to avold such effects as sparktng or~arctng, cllnglng clothing, and the Itke. Inasmuch as tt ts relatlvely easy for a person to accumulate the charge of approximately 2000 volts of electrostatTc ,: :
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dlfferential whlch gives rtse to sparlsing or arclng, as many persons know from placlng a key to a lock or shaklng hands after having walked across certain types of carpet, avoidance of exploslons or other undeslrable consequences of such dlscharges Is a result to be apprec1ated.
Alternatives to the hose 44 of Flgure 14 are contemplated as Includlng legwarmers as generally Indlcated at 48 In Flgure 16 and low-cut socks as generally Indlcated at 49 In Flgure 17. Each of these alternatlve forms may have courses of conductlve strands Interspersed wlth other courses 46 as descrlbed above. Persons skilled In the arts of manufacturlng such garments wtll be able to devlse stlll other leg engaglng garments whtch wtll achteve the deslred result of the present Inventlon.
Garments embodylng the present Inventlon may also be constructed for engaging a hand, as suggested by the mltten 50 of Figure 18 and the glove 51 of Flgure 20. In each Instance, a fabrlc 36 has been employed, generally ; ~ as descrlbed above. In the Instance of the glove 51, the glove Itself may be a plaln Icnlt fabrlc with the conductlve strand knlt Into place, In order to achleve a very thin glove useful In asslsttng entry into a rubber 25 ~glove such as used In a sterlle envlronment or wlthln a controlled envlronment chamber. In the Instance of the mltten 50, the yarn from whlch the mltten Is formed may be a hlgh temperature yarn so as to make use of the ~'~

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mitten advantageous In such envtronments as foundrles or steel mllls. As here used, "high temperature" means a yarn which substantlally maintains structural integrity and does not degrade at temperatures less than 550 degrees Fahrenheit. The phrase "structural integrity" is Intended to mean maintainlng, upon reaching an elevateci temperature, a tensile strength in the range of sixty percent or more of the tensile strength at room temperatures on the order of 70 degrees Fahrenheit.
"Degrade" is intended to describe melting, decomposition or other loss of structural form. Examples of textile fibers having the recited characteristics include aramid fibers and polytetrafluoroethylene flbers.
; The fabrlc used in mittens as just described may also be fabricated, using known technlques, into garments resembling T shlrts for engaglng the torso of a wearer. Such a proiectlve garment combines high strength, thermal reslstance, and static suppression in a partlcu!arly unusual and destrable way.
; In the drawlngs and specifications there has been set forth a preferred embodiment of the invention and, ` although specific terms are used, the description thus ;~ given uses ter~linology in a generic and descriptive ::
~ sense only and not for purposes of limitation.
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Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A garment for suppressing accumulation of electrostatic charges and comprising a body engaging member and a knit fabric forming at least a portion of said body engaging member, said knit fabric being formed of yarn knitted into courses and wales and including an electrically conductive strand knitted with the yarn, wherein said yarn is knit into stitches defining a ground and stitches defining loop pile extending from the ground, and further wherein said conductive strand is knit with stitches defining loop pile.

2. A garment according to Claim 1 wherein said conductive strand is a synthetic monofilament yarn having electrically con-ductive characteristics due to the inclusion of conductive mater-ials in the strand as extruded.

3. A garment according to Claim 1 wherein said fabric is formed of high temperature yarn.

4. A garment according to Claim 1 wherein said garment is constructed for engaging a foot.

5. A garment according to Claim 1 wherein said garment is constructed for engaging a leg.

6. A garment according to Claim 1 wherein said garment is constructed for engaging a hand.

7. A garment according to Claim 1 wherein said garment is constructed for engaging a torso.

8. A garment constructed for engaging a torso for suppress-ing accumulation of electrostatic charges and comprising a torso engaging member and a knit fabric forming at least a portion of said torso engaging member, said knit fabric being formed of yarn knitted into courses and wales comprising stitches defining a ground and stitches defining loop pile extending from the ground and including an electrically conductive strand knitted with the stitches defining the loop pile.