CA1156002A - Knitted sock - Google Patents

Abstract

Abstract of the Disclosure This invention is directed to a knitted sock having a leg part not extending above the knee of the wearer when in the normal position and composed of a fabric having less than 105 stitches per square centimetre when measured fully stretched in course and wale directions and at standard conditions for testing textiles. The sock is characterized in that the fabric-to-leg pressure prograssively decreases from minimum leg circum-ference portion of the sock to the top marginal portion of the sock at a rate such that the fabric-to-leg pressure at the mid-calf is less than about 60% of the value at the minimum leg circumference portion.

Description

1 1 560~

()VIL) KNIIL`i:[) S()CK
~ i..'i illVCllt iOIl iS concernecl with Icnitted hosiery for-rllen, WOmell ~IIlCI chilclren. The invention is directed specifical.ly to hosiery Lhat does not extend above the knee 5 of thc wearer, ancl recerred to as socks. In particular, but not excLllsively, t:he inven~ion re~la~es to socks having a leg length not extending above the mid-calf part of the human Lec, when in normal position (position of minimum energy) during wear. Included in this category of socks 10 are items known as "short socks", "arlkle socks", "anklets", "half hose", "crew socks", "below-the-calE socks", "mid-calf socks". However the invention also relates to socks that extend close to the wea-rer's knee and sometimes referred to as "executive length socks", "knee high socks"
15 or "walk socks".
I-lereinafter the term "socks" will. mean knitted garments for clothing the foot and leg that do not extend above the knee of the wearer when in the normal wearing position and composed of a fabric having less than about 20 105 stitches per square centimetre (700 stitches per square inch) when measured fu]ly stretched in course and wale directions and at standard conditions for testing textiles.
In the period, prior to approximately 1935, socks, as distinct from stockings which reached over the 25 knee, were chiefly of a length reaching to the wearer's knee, or else to the mLcl--calf part oE the wearer's leg, the latter being known as "half-hose". In orcler to restrain the leg of the knee Length socks Erom slippLng clown a wearer's leg whilst walking, circuLar garters ~enerally 30 made from rubber elastic braid were used. The leg of the ha]f-hose type of soclc was restrained Erom slipping by su~spenclers ? attaehed to the wearer's leg between the knee ancl ealf m~lscle, .~ncl ellpped to the top of the Leg o~E the sock.
3S ~pprox:Lmrltqly forty to f-Lfty yqars aç?o techrlology was cleveloped for lhe layln~ of rubher el.astLe thre~d Lnto the s~itches of knitted ~abrie, nrld thLL. technolo~y was .3_ use~l ~0 p1'0CIllCC .',o('kS Wi.ttl such thre--l(l lald into a number o~ kni.tte(l co~lrses at t.he top of the leg of socks. The thread so l.aid :into ~he knitted fabric constituted an eLclstic band at the t:op portion of a soclc le~, and in S referellce to :i.t the tcrm "elastic top" is commonly used.
I`he purpose of the elastic top was the incorpora~ion wi.thin the sock of means of restraining the Leg portion from slipping down a wearer's leg during walking, thus elirninclt:ing the need to have extraneous means 10 of restraint as described above. The elastic top in a below-the-cal.f sock is stretched when initially placed on the leg and thus grips the leg oi a wearer. After a period o~ wearing, dur:ing which the wearer walks with a normal gait and velocity of Leg, it is usual. for a sock to 15 progressivcl.y slip down ~he wearer's leg, Eorming wrinkles in the Eabric of the lower part of the leg of the sock.
This slippage commonly occurs even when the elastic top exerts pressure on the leg of such magnitude as to cause temporary skin indentation and irritation.
It is the purpose of the present invention to provide socks, particularly those with leg length not extending above the mid-calf position of wearer's legs, and which exhibit superior resistance to slipping down wearer's legs during walking also causing minima]. and generally 25 negligible skin indentation or skin irrltation.
It is recognized that the part of the human leg, from the location of mid-ealf to the location of minim-lm circumference, :is approximately the shape of an inverted truncated cone. When a sock is drawn on to the leg of a 30 wearer and located in a normal position for wear, the fabrie of the leg portion oE the soclc l.l.sually exerts a prçssure on t:he le~ of the wearer ~nd this soelc-to-l&g pre~ss~lre~ will geller~lly va-ry accordi.llg to position between t~e two l.ocations refer~e(l to above~ The pressures are 3$ excrted as a conse(lu&nee of the varying c:t-rcum~Eerent:lal &xten~ions ~iving rise to varylng circumferential tensiQns w~ hln the fabric o~ ~h~ leg o~ c~ sock.

11$6002 At any on~ pLace between the two locati.ons -indicated above (mid-calf and minirnum ]eg circumference), the force exerte~ by the fabric on to the leg in a circumEerential plane is, by virtue of ~he shape of the 5 leg, not norrnal to the ~eg surface. It may, there~ore, be resolvecl into two components, one being normal to the leg surEace ~nd the other one downwards aLong the leg surface, a fact to which reference is made hereinafter.
When a sock is first donned by a wearer, and the 10 top margin pulled some distance up the leg, its leg fabric is usually in a stretched state through tension belng applied in the action. The individual stitches are in an elongated and stretched condition. When the wearer starts to 1ex a leg and move it ~ently the stretched stitches 15 will change from their elongated to a more rounded form.
This form approximates to an equilibrium position for a leg ~ in gentle movement.
- When the wearer commences prolonged walking whether continuous or intermittent~ two main groups of forces are acting on the leg fabric. In the first group~are~
those which favour slipping of the leg fabric dowD the ~
wearer's leg accompanied by wrinkling ~(or buckLing) of~the fabric, whlle in the second group are those forces~which resist slipping and wrinkling of the leg fabric. ~
For a leg involved in ~he motion of walk~lng the chie~ pro-slip orces are:- ~
(a) That component o the Eorce exe~ed by tlle leg ~abric acting downwards along the surEace o the le~, 3Q (b) Thcl~ compo~nen~ of the gravitatianal force acting on the ma~s o~ the leg fabric par~llel ~o ~he sur~ace o the le~, ~`) That c~mp~n~n~ ~ the ~rce r~ult~n~ from he mamen~um ~ th~ sock nbrlc 7 ~he v~loc~y ~ whlch ch~nc~e~ each ~ime the wear~r'~s ~oot to~!che~ the ground.
Th. chi~ con~r~-~lip ~orces are,~

: -' --` 1156002 (d) That resulting from the friction between the leg fabric and the skin of the wearer, (e~ That arising from the fabric below~any portion which is tending to slip and~which ~ ~ ;
is due to resistance to displacement as regards location that is, slipping downwards, or to configuration, that is,~to wrinkling.
If the sum of the forces "a", "b" and "c'~'~is ~10 greater than the sum of the forces "d" and "e" in~any~
portion of the leg fabric then conditions exist for~the fabric to slip down the leg. This slipping will continue~
until conditions change to make the sums of the two groups~
o~ forces equal at which stage further slippingian~d~
15 wrinkling do not occur.
In constructing a sock in which the leg~.Ea~bric~
will not slip down the leg from the position of~equi~librium described above, it LS necessary to~ensure that~the~sum~of the forces "a", "b" and "c" is less than the sum of~thè~

2~0 forces i'dll and "e" by m;nimizing the magnitude of the~
pro-slip forces and maximizing the~magn~t~ude of~the~
contra-slip forces.
It has been dis~covered th~at by varying in~a selected manner these circumferential tensions of the leg S ~abric of the socks~and~accordingly ~he abric-to-leg presure, there can result socks in which the leg portlon -~
resists slipping down the wearer's le~s during walkin~
In the preferred cons~ruction of t~e~sock~he fabric-to-leg pressuré~progresslvely decreaaes from~the 30~ location oE mlnimum le~circumEerence to the mid-calf~
location a~ a rate so that~the fabric-to-le~ pressure~ at~
he mid~calf~ is less than 60% ~ ;~h~ valu~ a~ the~minimum ir~um~r~n~
~ ; ~onv~ni~nt~ly~ ~h~ d~cre~se irl the Eahrie-to~
; ~ 35~ pr~sur~ ~t the mid~c~l~ ls ~ ~q~w~n 5% ~o 60~/o ~ ~ha~ a~
the loea~iQn~ ~f~ mLnimum 1~ cireum:~cr~nce, and pr~ rably o b~ t w~n ~:~% ~ q/~

:

-6- 11 560~2 When the invention i5 applied to a sock that does not extend to the mid-calf the minimum percentage decrease in the fabric-to-leg pressure from the value at the minimum leg circumference to the top marginal portion is 40%
multiplied by the ratio of the distance from the minirnum leg circumference to the marginal top of the sock to the distance from the minimum leg circumference to the mid-calf.
It has been found that a leg fabric which resists slipping down a wearer's leg can be constructed initially by providing a portion of fabric around the place where the leg has minimum circumference and extending it down to the ankle joint.
This portion of fabric has moderate to high circumferential t~nsion whilst on the leg and, therefore, moderate to high fabric-to-leg pressure. Then there is .- required'a decreasing of the circumferential tensiRn and '~
fabric-to-leg pressure at a selected ~nd relatively'rapid rate whilst proceeding from the region of minimum leg~
circumference to the top margin of the sock.
~ ~ 20 In the accompanying drawings, Figures 1,~2 and 3 -~ ~ are diagrammatic illustrations of-socks accordins to~the present invention.
. The ability of a sock of such construction~ to resist slipping down the leg of à we?rer m~y be e~plainéd 25 by considering the leg of the sock as a series of bands of fabric (as illustrated in Figure l).
The portion of ~abric at the minimum leg circumference (band 1) and extending down to the ankle joint is located on an approximately conical shaped section 30 of the wearer's leg and, there~ore, the circumferential ~abric tension has a force component 'parallel' to;the leg sur~ace tending ~o push the fabric upwards. Thus the~
p~sition o~ ~abric at the minimum leg circum~erence p~ssess~s an added ~bili~y t~ resls~ displacement 35 d~wnwards. Fricional r~lstanGq is also pres~n~. ~
For ~h~ narrQw band of ~abrlc ~2) in ~igure~l to be able to sllp downwar~s, i~ must ~ither displace downwards thq fabric band (1~ or cause this band to~orm a wrinkle~ or'buckled section (~). Fabric band (1~ r~sls~s 40 slipping downwards as already explai~ed, however.
~J

~` 1156002 I~ should be noted that the aetion of the leg Labric of a soclc becc)ming wrinkLecl involves an increase in fabric circumference and, therefore, an increase in circumferential tension in the wrinkled fabric. Thus lncipient buckling or micro-wrinkling, should it occur, will contribute to the contra-slip forces to resist slippage of band (2). This contributecl force would act upwards from the wrinkle, in the leg fabric and parallel to ~he surface of ~he wearer's leg. It has been found that with suitably selected values for circumerential tension in bands (1) and (2), no slipping or wrinkling of~fabric -~
occurs in wearing and walking. ;
In a similar way the possibility of fabric band

(3) slipping and causing band (2) to slip or wrinkle can be considered. With opLimum selected values of the circumEerential tension in the respective bands, no slipping or wrinkling will occur. The whole of the Leg fabric can be considered in this way and found to be ~free from slipping and wrinkling.
The practice of using slowly varying fabric-to-leg pressures has been employed in surgical or therapeutic hosiery, "leg-support" or "support"~stockings, pantyhose and socks. All these articles are designed with concern for the blood circulation in the human leg and ~rom the recommended pressure dif~erentials between minimum leg circumference and o~her loca~ions up the leg, it can be ~alcuklted that the principle applyin~ in the more effective articles is or the clrcumferential tension in the leg abric oE the article on a we~arer's leg to~rem~in substantially and approximately constant over the whole leg.
Examples oE such an artlcle o therapeutic ~osiery are de~scrl~ed ln~various United States Pa~en~s whi$h 3~ate thA~ ~h~ c~mpre~siv~ ~o~ce ls sukstanti~lly unlEq~m through~ut ~he l~n~th of ~h~ ar~ wh~n in u~.
~5 In -r~ard t~ th~ de~lrabLli~y o~ ~ unl~orm~
c~mpr~$Lv~ or con~ric~lve ~rc~ in therap~tlc hosiery w~
woulcl r~eer in p~r~lcular t~ USP 2,~4l,~ Gol 5 llnes 35 : :

;

1 1~6002 to 44, ancl USP 3,386,270 Col 1 lines 27 to 59.
In other ~herapeutic or support hosiery there has been proposed variation in the Eahric-to-leg pressure along the length oE the ]eg, such as in USP 3,889,494, however there is no suggestion that the full length stocking describecl has stay-up characteristics. Further as there is a substantial reduction in fabric-to-leg pressure in the knee area, the portion of the s~ocking above the knee would not be non-slipping in the manner proposed by the present invention. It should also be noted that in the area of the leg immediately above the knee there is a progressive increase in fabric~to-leg pressure while the leg in this area is progressively increasing in diameter.
These two facts have a cumulative effect promoting downward slipping'oE the stocking.
The use of progressively increasing horizontal contriction in the welt of a stocking is proposed in USP
3,392,553 which is stated to be applicable to both~above the knee and below the knee stockings or socks. However ~20 the purpose of the variation in the constriction;is stàted~
;to be to achieve "uniform or equal compressive ~orce ~
against all areas of contact with the wearer's lég".; This is contrary to the present invention and would not aehieve the non-slip property in the manner of the present invention. Also it must be noted that it is only proposed for the variation in constriction to exist in the~ welt o the stocking or sock whLch is then merely an elasticLæecl top type stoeking or sock.
In order to characterize the socks of the present lnvention, and to di~ferentiate them froln surgical and thcrapeutie hosi.ery~ and also from socks ~i~h elastic tops ~ncl those w-Lth c~n~t~n~ eourse lqn~th~ Q:E yarn in th~
portl~n up to th~ e~ nd s~lppor~ ~ock~ test~ ~r ~rLc pre~s-lr~ h~v~ ~e~n m~de.
D~le ~o ~hq nqvelty af ~h~ ~onc~ept ~ ~he type of ~Cl$k ~ the pres~n~ inven~on th~re i~ n~ wi~ely reeo~ni~cl ., 1 156~02 _9~
or standarcl testing apparatus and method for fabric-to leg pressure exer~e~ by socks. It has therefore been necessary to choose an apparatus, adapt it Eor use with socks and deve.lop a test rnethod.
Of the two widely recogni.zed testing instruments and methods for leg support hosiery namely "Support Hosiery Testing Apparatus and Method", USP .3,'375,956 invented by Robert Peel and assigned to National Association of ~Hosiery Manufacturers Inc., Charlotte, N.C., U~S.A. and the "Hatra Hose Pressure Tester", deveIoped by Hosiery and Allied Trades Research Association, Nottingham, England and manufactured by Shirley Developments Ltd., Manchester, England, both based on the same principle but differing in design, the latter was selected merely because Lt was more readily adaptable to the testing of socks. It provides a measure of circumferential Eabric tension which can be converted to fabric-to-leg pressure for leg locations having varying radi.i of curvature.
The adaptation of the Hatra Hose Pressure Tester involves replacing the woman's foot portion by ~
appropriately larger ones for mens' socks and~appropriately smaller ones for children's socks then extending the:
suspender clips from the locations existing for hosiery of which the legs extend above a wearer's calE, so as to be : 25 able to secure during test various socks with le~s which extencl to locations below a wearer's cal.E. Additional modiication for testing children's socks involves replac~ment o:f the fixed and removable arms by ones with smaller cross section. ~ ;
For purposes of specification of socks of the presen~ invention and control oE quality in manu~acture : va~ apprc~prl~t~ s~in~s o~ th~ Hosq Pre~sure T~st~r hav~ h~n adc~p~d. Fc~r m~n~s so~k~ clesi~necl ~ fi~ wearers c):~ soc.~k~ ~lz,~ t.~ 12 :lnclu~ivq (~t len~th ~ :ln~h~
12 in~hes ~r 25 cm ~o ~O:cm corr~p~ndin~ to shoe~slzq~ 6 ~o 10~ ~ A~s~ralian sho~ siz~ 6 ~o ~0 correspond ~o Am~r1can soGk ~1æ~s 10 l~o 13~ incluslv~ - re~r Austr~l1ia :
,. .

Stanclard 1923-1976) the setting adopte~cl was the l'M"~
pOSitiOIl oE the movable arm. When a sock is pul~led;~on~to the "V" formed by the fixed and movable arms, it~ assumes the appropriate configuration that it would~have~on~the;l~eg~
of male wearer whose leg dimensions are ~he average~for~the population within this sock size range.
Since the "M" position is the one designated for women's surgical, therapeutic and support stockings and pantyhose comparison and contrast can be made between the pressure generated by these hosiery it~ms at various ; locations on the leg and by the socks of the pre;sent invention. ~ ~
Furthermo~e, since circumEerentiaL lengths for the average leg in various~populations requiring~the~one~
sock size (men, women or~children) can~be~closely matched on the Hatra Hose Pressure;Tester (in~original or mod~if~ied~
form? figures for fabric-to-leg pressures on average~legs~
are~considered to~closely approximate~ to those obtained by use of the Tester.
20 ~ ~ The~purposé of Tablé 1 is to indicate the ~
; fabric~to-leg pressures ;applicable to all socks of~the ~;
present invention and~contrast these with pressure~fl~ures indicated in two prior United States Patents, a~reco~nized quali~y standard, a recommended quality standard and also 25 ~wi~h pressure~ figures which~are typical of~three types of men's~socks of;conventlonal type.
It is seen t~a~t socks of the present invention~
diff~ markedly and~the;re~orej belon~ to a differén~ class~
me~ ~o~convqlltion~l sock~ and ~ ~ur~lcai~
30 ~h~rR~u~ic and l~ upp~r~ h~sl~y ~ncl s~lpp~rt ~oc~s ~nd r~ oh~r~cterix~d;by a muoh ~r~e~ cle~r~5~
abr1c~o~ pr~u~e ~rQm ~h~ l~c~ion o~ mlnlmum le~
c ~l m ~ ~ -r q n ~ m l ~l - ç F~

:

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3 ~ r U~ ~ nq ~
oq ::r _ _ ~ ~ ~ :
o n ~D ~o o r~ ~:
~' O l l O l ~fl l O ~ ~
;.` c ~ o~q ~ ; q o~OE~ : ~

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rr ~q l l l O Q ~ , ~ ~
3ro = ~ 3= ~ _ _ = ~ ~ :
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~ l l ~ o ;: ~ o a P~ ~ a~: ~ ~ ~
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ID 1-0 ; ~ :~I I I I ~r rl O--q o :r~ rr p~ ~ ~n ~ O
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~ qq : ~ L~ ~q ~' r ~ :
rr : ~ ; ~ ~ $ : N q~
= == =~__ ~ ~_r _=
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: l : ~ S~ ~ ~ ~nq c~ ~ ;
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P~

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-~` 1 1 56002 Ref.l USP Re 25,0~6 Oct 3 1961. Example lll: Pressure in ankLe 20 mm o~ mercury, in cal~f 19 mm and in Lower thigh 18 mm.
Ref.2 Technical Production Guidelines for Two-Way Stretch Surgical Stockings w1th the Quàll~ty Mark.
(Quality Mark Association Eor Surgical~Elastic Stockings, Hohenstein, W. Germany, 1972)~
Ref.3 Levels acceptable for therapeutic value~
(Consumer Bulletin Sept., 1972, pages 32-35, `
; 10 Consumers Research Inc., Washington, U.~S.~A.).
` ~ Ref.4 USP 3,386,270 June 4 1468. From the statement in ~his patent that the compressive force on the anlcle (minimum leg circumference) may~be;~the same as on the remaining portions o~ the leg~, it;can be deduced that for a minimum leg circumference of 24 cm and a mid-calf circumference of;~35~ cm which are the average figures f~or~men~wea~ring;
sock size 6-10 (Australian) that~the ra~tio~of~
fabric-to-leg pressures~at the two positions~ls 20~ 100 to 69 - As previously referred~to in the case of~socks~of~
the presen~ invention of which ~he of~ the legs is~such that the~marginal portion~of;the sock reaches a point below the mid-calf of wearer's leg~s when the a~ric is in the normal 25~ position of wear, the~percentage Eigure for the mlnimum ecrease of ~abric-to-leg~press;ure from~the minimum leg circumference to~the top~ marginal location will be the same ; proportion oE 40%~as the distance between the mini~mum leg~;
circum;~erence and top margin o the sock is to the~distance 30~betw~en ~he minlmum l~g~circumference;~and~the~locatlon Oe h~mi~=e~l cir~m~er~n~
T~le 11 illu~Fa~e~ thl~ case.
:` : : ::

. !

' ~
. ' ' : . . ' .

, ~3 Table 11 Mens' socks with top marg:in of leg ~:
below mid-calf of wearers : :

: .,___ _ -__ ~._ ._ _ ._ _ ~ Fabric to Leg Pressure ~
, .,.. ~
Location Actual Decrease from Value Percentage a~ Minimum Leg . CircumEerence ._ _ _ . __ ~ __ _ _ _~_. .
: Minimum Leg 100% :
_ _ _ ~
Top margin when :
: located a distances above minimum leg circum-ference as Eollows- ~ : ;
60 mm 89% maximum ~ 11% minlmum ~
90 mm84% maximum 15% minimum~::: : :
120 mm78% maximum 22% minimum~
150 mm72% maximum~ 28V/O minimum 180 mm~ ;66% maximum ~34V/o minimum , ~ ~ ' :Mid-Calf ~ ~: 60%~max-imum - 40% minimum : ~ :;

, .
.
~: : ' ;:
:

' ~ ' .

:: ~

1 1560~2 While it has been sta~.ed that ~his invention is particularly applicable to socks having a leg length not extending above the mid-calf part oE the human leg when in the normal position of wear, nevertheless, it is applicable 5 to socks which extend above the mid-calf, ~or example knee-leng~h socks.
Socks having a leg length extending above the mid-calf are characteriæed by a decrease in fabric to leg pressure at mid-calf oE at least 60% from the figure for 10 fabric-to-leg pressure at the minimum eircumEerence position, with fabric-to-leg pressure in locations from mld-ealf to the top margin not being critical. Owing to the resistance to slipping e)xhibited by the leg fabric below the mid-calf, the cLreumEerential fabric tension and 15 fabric-to-leg pressure in the leg portion between mid-calf and knee will not need to be as great as required in knee length socks of conventiona-l construction, and thus ~he socks in addition will produce enhanced personal comfort.
While the actual fabric-to-leg pressure~at the 20 minimum leg circumference may be relatively high~even up to 50~mm mercury, preferred ranges are minimum leg -eireumference about 8 to 16 mm mercury, mid-calf eireum~erence about 2 to 6 mm mereury.
As it has been recognised that frietion between 25 sock fabrie and the wearer's skin helps the sock to resist slipping down the leg as a result o walking, then it ollows that fabrie-to-leg pressures must be adequate to :
give rise to some use~ul Erietional foree even in the upper parts o~ the leg o~ the sock where the fabric tensions may 30 be r~latively low.
I~ ls ~o~non prae~leq t~ cl~si~n a s~ek to fi~
rfln~ og on~ or mor~ o~ siz~s. S~h ~oot slæes m~y be d~ignat~d by ~h~ ~læq or by ~o~t len~h ~c~or~ing ~o th~
sys~em us~cl. Withln ~ny r~ng~ o~ ~n~ ~r m~re ~oot si~es, ~S ~h~ e~n~ours ~ ~h~ and l~g~ ~ th~ popula~ion o~
w~arer~ vary an~ in ~his pa~ ular case, ~h~e por~lons o~ l~g~ loea~qd~b~low th~ kn~. The on~ de5i~n of sgek i~, :~

nevertheless expec~ed to f:it not onl.y wearers' feet of varying cl:imensions but also wearers' legs of varying dimens.ions. Socks with the characteristics of this invention can exhibit resistance to sli.pping down wearers' legs ancl minimal or negligible skin :indentation or skin irritation for a high percentage of any population of wearers and for selected values of sock characteristics this percentage will exceed 90%.
The performance in wear exhibited by the socks of the present invention cliffers noticeably, therefore, from that of mid-cal~ and below the cal~ socks having the prior known elastLc tops. In these latte-r types of percentage o populatLon which fincls resistance to slippi.ng down the leg during wa:Lking together with freedom from skin indentation 15 and skin irritation may be as low as 10%. The production:
of socks with legs not extending above the mid-ca~lf, without discrete elastic tops, but with an elastic yarn : knitted or laid into the whole length of the leg:fabric with constant yarn length per course does not greatly 20 increase the percentage oE a population of wearers with socks which resist slipping down their l.~gs during walking.
The required fabric-to-leg pressure of the~sock may be achieved by incorporating elastic threads into the fabric of the sock. These threads may be made elther:
25 wholly or partly of elastomeric material and/or textured or otherwise processed polymeric Eilament or fibre impartlng elastic quality to the thread.
The variation in the pressure may be achieved by va~ying the quantity of elastie thread or by varyin~ the ~0 kension in th~ th~ad durin~ the ~e~ual lncorp~rat:i~n th~r~o~ ino ~h~ .~ahrle. rhe varia~ion in t~nsion may b~
; obtaln~cl by varia~ion l~ ~he ~orm Qr ~iz~ o~ ch used.
~he beh~vi~r o~ th~ s~eks in resis~ln~:~lippage : clown the leg as a re~ul~ ~ walking ls as~is~ed hy a ~5 r~l~tlv~ly high fabrle-~o~leg E~ietioll~ su6h as ean he ~ ~bt~irlq~ wlth the use ~ spun yarn$ in thq kni.t~ed ~abric~
: an~ partieularly bu~ no~ necessarily~ spun yarns eontalning -1 15~002 wool or cotton.
~ suitable knitti~g machine for production of a sock accordin~ to the present invention is one in which there is t~le capability of altering the length of all or some of the yarns fed (knitted or laid) into the knitting needles at each knitted course or at pre-determined intervals during the knitting oE the leg of the sock and/or varying the feed pattern Eor yarns. As an example of the second alternative a particular yarn may be fed into the needles at every course, every second course, or not at all ~varying the yarn course clensity).
Knitting machines may have cylinders varying in diametcr from approxlm~tely 2~ inches ~6 cm) to approximately 6 inches (15.2 cm) and may have a num~ber of needles varying from 36 to 280.
Fabric construction may be plain knit (also known as single jersey), rib knit or jacquard knit.
Sock construction may include a heel pocket knitted by a reciprocating action, or it may be of~a "tube"
type without such heel pocket and with or without yarn knitted or laid into the tube fabric to form a heel patch.
Knitting yarns employed in the production of the sock may be any of those commonly used in the present art. Such yarns may be spun from the following fibres: cotton~ wool, acrylic, polyamide, polyester, regenerated cellulose or may be con~inuous filament yarns oE tke Eollowing types:
polyamide, polyester, regenerated cellulose, spandex (segmenLed polyurethane), rubber (natural or synthetic).
In addition knitting may be perf~rmed ~rom any mixtures a~ ~ny kwa or m~r~ o~ ~ny of th~ flb~vq mentianq~ ~ibr~s or ~anL;inuoLIs Eilamqnt~ h~ ~o~m of bl~ndcd mixurqc~, twls~qd mix~ure~ ar ~s c~r~-sp~n yarns or wrap~ed ~i.bres or ~ilamqn~ y~rns.
Thls invet~ion partl~larly concqrns ~h~ leg 3$ par~ion o~ ~he ~a~k~ ~hc knit~in~ ~ th~ le~ ~tld thq settin~ o~ thc 1~ ~abrlc.
A~ter c~mple~lQn o th~ knltting a~ th~ leg o~

the soclc, the knitLLng of the heel, Eoot and toe is performecl according to the chosen design of sock, and according to known art. Following completion of knitting the toe opening (if present) is closed by any of the present available means.
It is an optional current practice to place a sock, if it contains some Eibre which can be plasticized by heat and steam on a flat metal former of a shape a little larger than that oE the sock in a Elat relaxed state.
Socks Eitte~ to former are placed in an autoclave and subjected to steam pressure, or in other vessels and subjected to heat, in order to achieve a moulding and setting o~ the sock fabric and thus a certain shape to the sock. Depending on whether this is done before or after scouring and dyeing it is known as pre-boarding o~r post-boarding respectively.
In order to assist in the practical appl~ication oE the present invention examples of constructions of sock will now be described with reference to ~igures~ ,2 and 3 of the accompanying drawln~s. The socks in the~exampl~es ;~
are intended for fitting the~Australian adult male `
population, the leg and foot characteristlcs of~which are~
similar o those oE many other nationalities. ~To ~it nationalities with~diferent~oot and leg character~istics ~5 small modifications may be required but the same principle relatino to the rate oE decrease of fabric circumferential ;~
tension and fabric-to-le~ pressure Erom minimum~leg~
circumference to the top margin of the sock will~ apply.
~xanlple ~
Th~ s~ck shcwn in Figur~ 2 -ls Icnlttqd on a 3~e~d Kom~t TJ2 Icni~ln~ m~hin~ o h~vin~s for ~ach dlam~ker~
M176 :n~dlq~ rîh~ h h~s ln th~ lc~ port:Lon be~w~n th~
lincs ~ an~ C, ~ ~abric consructl~n ~f :I x 1 ril~ t:yp~, Char~c~cri$tlc~ ~f th~ fabriç ln ~h~ r~pcc~iv~sec~ion~ o h~ le~ p~rti~n o-~ ~h~. ~o~k (t~ ran~e ~
~peci~i~d ln ~xampl~ 2), ~rq shown ln th~ ~ollowing Lable.

,: ~ :

1 1560û2 - --~: r 0~
l I I I 1 1 : ~ (n O
C) ~ ~ ~ ~ : W o ~ ~:
o, . ~ _ __ _ n ~ ~ n ~ n ~n ~ rt ~ O O ~ ~ ~ CO O ~ CO O
~t C ~ n rt u~ P~ n n ~n ~h O ~ O ~ O i ~ 0 ~ 0 t:d O ~ O Q~ 0 : ~ :
~t n tD ~ rr :rX ~ ~ ~ X X O E X X X o ~ X ~ :
~ J ~ ~ :

: ~ o~ ~;
' :, ~ ~ Z- ~ o~:
: ~ ~ ~ ~ W ~ ~ :
~: : ~ . ~ o :: ~ ~; Qq 0 ~ :
: _ ~ .: :. . ._ . ~ ~ ~ ~ ~`
: ; : U, a~ ~ ~ ~ 1 3 N tt . ~
~ ~ : ~o ~ ~ ~ :
. :: ` ;
: ---- ~ _ _ __ ~ ~
: ; ~ o ~ ~ :

I ~

: ~ c~ 3 , ~ ~ ~:
I U~ Ul j I
~ ~ ~ ;r ~ ~ :~ ~
. : ~:

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Ill this example the required variation in fabric-~o-leg press~lre is obtainecl by varying t~.e number of courses of 235 dtex Spandex relative to the total n~lmber of courses in the respective sections of the sock. ~
5 This sock provicles comforta~ble Eit without s~kin irritation ancl will resist Slippitlg down the leg o~f~90% of that populatiGn of wea-rers for which it was designed.
Example 2 .
In this example there is a continuous decrease 10 in Eabric tension and abric-to-leg pressure in a portion of the sock between E (refer Figure 3) which is approximately the position oE minimum leg circumference and D.
This is effected by contlnuously varying~the~
;~ 15 stitch size of the 1/57 tex yarn and the co~rse~len~th of~
the 235 dtex double covered spandex. The Knitting~ Machine in this example is an Esta, Model JU3 with 4 inch~cyllnder diameter and having 176 needles.
Details of yarn~and characteristics of~the~
~20 respective se~ctions of the leg of the sock ~it~tin~g~men ~ ;
with foot length of 10 to 1~ inches inclusive or~ 25~to 30 cm corresponding to shoe sizes 6 to 10 inclusive) are shown in~the following table.
:

-~: :
: ~
: ~:
~: :

' :

: ~ ~

:

.

1 1~6~02 -20- ~

t~ ~io~tD ~ ~ :
~ ~ ;~ ~
. : ;
:
_ . ~ __ :
~ :' :
:: ~ : ~:: ~ o~ ~ ~ 3 1-- ~ ~ ~
1--~, <P~ ~ ~ ~ tD t~ Q. rD ~n ~ ~ .

: ~P~ X (~ 0 ~ .~
: ~ ~ : ~ :X P~ O O ~ X ~ 3 3 : : . ~q:
t ~` Q ~: : ~ ~
~: ) ~ C (D ~ ~~ O ~ ~ , ~ :' :

: ~t ~ J
: ~ F ~ o' ~

: : ~ : ~` o~
: ~ ~
~ :: ~ ~

:; a~ , cr ~ ~ ~J ~A ,~ ~ :

~ :~
:- : ~ : : : ~o n ~
: ~ ~ rr ~ o ~ ~ ~
~ P ~ 0~ 1 ~ Q ~ ~ ~

:: : : : ~ ~ ~:
~=e~ __ :: : , :~ ~
: : ~ ::

: ~ : : ~ ~ ~ 1 1 ~ ~
g,C:~ W ~ (P ~ ~ O
: : ~ ' :: ~
, ~ : : : __ ::
___ __ __ ,~ ~_ :

: :

::
,: ' :

~, ~ : : ::
:

` ~` 1 15~02 ~ his sock provicles comEortclble fi~ witIlout skin irritation aI-d wîll resist slipping clown the leg of over 90% of thclt population of wearers Eor which it w~as designed.
In all the above e~amples, a~ter completion o~
knitting the toe openings of the soclcs were closed by seaming. The socks were ~hen scoured at 45C in an~aqueous medium containing an appropriate detergent, rinsed~, dried, placed on metal shapes in an autoclave, subjected~to steam for from 40 to 50 seconds at a temperature in the range of 119C to l24C, and excessive moisture removed by convéction drying with hot air. ~ ~
While the ~oregoing exarnples and tables have referred to men's socks which by virtue of a "stret~ch" yarn and/or thread component have fitted a range of~fooE~sizes~
~15 co~responding to shoe sizes 6 to 1~ inclusive, and~to~socks ; with legs designed to extend to~various points up to the mid-calf in one case and to~extend above~the mid-cal~ in ; ~ ~ another case, the present inventlon may be employed~to ~;
provide, additionally, socks of the~folLowing types -~
~ Men's~s~ocks of any leg leng~th in which one~ design (or construction~fits only one foot size~.
Men's~socks designed to fit foot sizes greater than corresponding to shoe size 1~ (Australi`an) or equivalent.
Women's socks of any leg length, foot size and design.
Chlldrenis socks of any length, foot size~and design.

: ::

:

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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 knitted sock having a leg part not extending above the knee of the wearer when in the normal position and composed of a fabric having less than 105 stitches per square centimetre when measured fully stretched in course and wale directions and at standard conditions for testing textiles, characterized in that the fabric-to-leg pressure progressively decreasing from minimum leg circumference portion of the sock to the top marginal portion of the sock at a rate such that the fabric-to-leg pressure at the mid-calf is less than about 60% of the value at the minimum leg circumference portion.

2. A knitted sock as claimed in claim 1 wherein the fabric-to-leg pressure at the mid-calf portion is between about 20% and 40% of the value at the minimum leg circumference portion.

3. A knitted sock as claimed in claim 1 having a leg part not extending to the mid-calf of the wearer when in use wherein the percentage value decrease in the fabric-to-leg pressure at the top marginal portion from the value at the minimum leg circumference is 40% multiplied by the ratio of the distance from the minimum leg circumference to the marginal top of the sock is to the distance from the minimum leg circumference to the mid-calf.

4. A knitted sock as claimed in claim 3 wherein the percentage value decrease in the fabric-to-leg pressure at the top marginal portion is 80% to 60% multiplied by the ratio specified in claim 3.

5. A knitted sock as claimed in claim 1 or 3 where the decrease in fabric-to-leg pressure is step-wise from the minimum circumference to the mid-calf or to the marginal top of the sock.

6. A knitted sock as claimed in claim 1 or 3 wherein the fabric-to-leg pressure in the minimum leg circumference portion is in the range of about 8 mm to 16 mm mercury.

7. A knitted sock as claimed in claim 1 or 3 wherein the fabric-to-leg pressure in the mid-calf portion is in the range of about 2 mm to 6 mm mercury.

8. A knitted sock as claimed in claims 1 or 3 wherein the sock extends above the mid-calf of the leg.