US3402575A - Knitting of tubular articles on circular knitting machines - Google Patents

Description

KNITTING OF TUBULAR ARTICLES 0N CIRCULAR KNITTING MACHINES Filed Oct. 14, 1965 3 Sheets-Sheet 1 FIGJ. I

IA/VEx/fo e FOL/ u ees/e 0y R. PEBERDY 3,402,575

' Sept. 24, 1968 KNITTING OF TUBULAR ARTICLES ON CIRCULAR KNITTING MACHINES Filed Oct. 14, 1965 3 Sheets-Sheet 2 5 v a 2 a a 6 m B Y .3 v F 9 r///// /AA,A 2 n llllll. llbll. llll l8 -2, A w w a A? k w v t a &

Im/EA/foe Tenn/0 105851919X yea- Sept. 24, 1968 KNITTING OF TUBULAR ARTICLES 0N CIRCULAR'KNITTING MACHINES Filed Oct. 14, 1965 v 3 Sheets-Sheet 5 INvENToR R01. ND ?'8ERJ United States Patent 3,402,575 KNITTING 0F TUBULAR ARTICLES 0N CIRCULAR KNITTING MACHINES Roland Peberdy, Leicester, England, assignor to The Bentley Engineering Company Limited, Leicester, England, a British company Filed Oct. 14, 1965, Ser. No. 496,007 Claims priority, application Great Britain, Oct. 16, 1964, 42,246/64 Claims. (Cl. 66-107) ABSTRACT OF THE DISCLOSURE A procedure and means for knitting a succession of tubular articles on a circular knitting machine by which each article is pressed off from the needles on its completion and a fresh course to start a succeeding article is commenced during the pressing off of a preceding article while a portion of yarn temporarily joins the articles, such joining portion of yarn being severed before pressing off of the preceding article has been completed. The means provided operates needle actuating cam means for the pressing off of each article and feeds yarn extending fom the end of a complete article into the hooks of the needles from which the preceding article has been pressed off, and also operates to sever the yarn in a length thereof extending across a small group of needles between the substantially completed and newly commenced articles.

This invention is for improvements in or relating to the knitting of tubular articles on circular knitting machines and is concerned more particularly with the production of knitted articles of footwear. The invention has for an object to provide a simple and effective procedure for the production of a succession of knitted tubular articles. The invention may be applied conveniently to use with circular rib knitting machines and especially to machines of the opposed co-axial needle cylinder type.

In the production of mens socks it has been the practice for many years to knit the sock blanks in continuous succession in string formation joined end to end. After the production of a string of sock blanks the individual blanks are separated by hand either by cutting or by removal of a draw thread and afterwards closed at the toe end. The separation is a time consuming operation and proposals have been made to provide a procedure whereby the socks can be separated automatically. In the proposals so far made certain disadvantages are involved either by impairing the quality of the product or by introducing difficulties in procedure or introduction of an additional operation. The invention seeks to provide a procedure wherein such disadvantages are largely or wholly avoided.

In accordance with the invention there is provided a method of knitting a succession of tubular articles on a circular knitting machine according to which each article on completion is pressed off from the needles and, before its pressing off is completed the setting up of a fresh course is commenced to start the next succeeding article with the yarn temporarily connecting the articles together, and during the pressing off of the preceding article the yarn joining it to the succeeding article is severed to separate the articles from one another. Thus a very simple procedure is provided whereby a succession of tubular articles is knitted each being automatically separated immediately after its completion from the succeeding article.

An important advantage of the improved procedure is that the yarn feeder can be maintained in feeding position during transition from the knitting of one article to the knitting of the next, thereby avoiding the need to take any special steps to cause the free yarn end to be taken by needles which are devoid of stitches. The yarn held by the last needle to knit a preceding article is laid across the stems of a group of needles immediately beyond the last needles holding loops of the preceding article and the severing takes place in a short length of yarn laid across such needle stems. The severing of the yarn takes place after the yarn has been taken into the hooks of the needles succeeding said group and whilst the short length of yarn laid across the needle stem is held between the needles succeeding said group and those still holding loops of the preceding article. Such severing takes place after the initial course of the succeeding article has been commenced by movement of needles into the hooks of which the yarn has been laid.

In practising the invention the severing of the yarn between succeeding articles may be etfected by subjecting the yarn to local strain to fracture it. Such fracture may be brought about by diverting a portion of the yarn to elongate its path and thereby set up the bursting strain which diversion may be brought about by a sinker movement.

The invention also comprises a circular knitting machine organised to knit a succession of tubular articles and having means arranged to press off each article as soon as it is completed, means for feeding the yarn extending from the end of a completed article into the hooks of needles from which the fabric has been pressed off to commence setting up of a new course before the preceding article has been fully pressed off the needles, and means whereby after the preceding article has been completed and the new course started the yarn extending from the preceding article to the succeeding article is severed to separate the articles. The yarn severing means may consist of means for subjecting the yarn t0 localised strain to burst it.

The yarn severing means conveniently comprises means for operating sinkers at appropriate times to engage yarn between the appropriate article and the next succeeding article and cause the yarn to be severed.

A convenient procedure for practising the improved method and an improved machine constructed and operating in accordance with the invention will now be described by way of example with reference to the accompanying drawings in which:

FIGURE 1 is an elevation view of a circular knitting machine to which the invention is applied:

FIGURE 2 is an enlarged detail elevation view in central cross-section of portions of the needle cylinders of the machine showing an article about to be pressed off and the commencement of knitting a succeeding article, and

FIGURE 3 is a developed view of a cam lay-out employed in the cam system of the machine being a machine having two yarn feeding stations.

The invention is illustrated in the drawings as being applied to an opposed needle cylinder circular knitting machine suitable for knitting mens socks and organised for transfer of double ended needles from one cylinder to the other in a manner well known to those skilled in the art for the purpose of changing between plain knitting and rib knitting as and when required.

It is to be understood, however, that the invention is also applicable to a machine having only a single needle cylinder as used for knitting plain fabric for example a machine organised for knitting ladies stockings or one organised for knitting other plain tubular fabric.

Referring to FIG. 1 the circular knitting machine therein shown is of generally orthodox form comprising a supporting frame 10, bed plate 11, lower and upper needle cylinders 12 and 13, and a main control drum 14. Lower and upper cam boxes and 16 are also shown, and the operation of movable instrumentalities used in controlling operation of the machine, such as bolt cams and yarn feeders, is effected by control rods banks of which are indicated at 17 and 18. The machine also has supporting mountings 19 for yarn supply packages and brackets 20 and 21 carrying mountings 22 and 23 for yarn guiding and tensioning means.

The circularly knitted tubular articles, in this case mens socks, are delivered downwardly through the bottom cylinder 12 into a discharge tube 24 through which they are drawn by air flow or suction to a delivery cup 25 from which they are discharged at appropriate times into a removable bucket-like container 26.

Further details of the machine can be seen from FIG. 2 which shows a central section through adjoining parts of the needle cylinders 12 and 13, certain orthodox parts of the machine being shown diagrammatically in block outline form so that parts relevant to the invention can be seen more clearly. Thus the cylinder 12 is shown equipped with bottom cylinder sliders 27 carrying double ended needles 28 and within the upper end of bottom cylinder 12 there is a sinker ring 29 carrying inside sinkers 30 having butts 31 controlled by sinker cams 32, 33. A tubular knitted article practically complete and partly pressed off from the needles is shown at 34 and it has loops of its final course still held on needles of the bottom cylinder indicated at 28a in FIG. 2 and on other needles to the right thereof the heads of which are below the top of the sinker ring 29 and therefore not seen. The fabric still engaged with on these lowered needles is indicated at 35. To the right of the fabric 35 as seen in FIG. 2 there are seven raised needles the heads of which are indicated at 2817, these being the first needles from which loops of the article 34 were pressed off.

The socks 34 are normally knitted from the top or welt end to the toe using both the main and back feeds where appropriate and the procedure following the completion of each sock blank will now be described with reference to the cam layout shown in FIG. 3.

Following knitting of the toe pouch of the blank 34 by the normal procedure of reciprocatory knitting, complete circular courses of plain fabric are knitted at the main feed to provide in known manner unravelling courses which will afterwards be removed following closing of the toe end as by linking. On reaching the point where the next sock is to commence the back feed bolt cam shown at 101 (FIG. 3) is introduced to engage a small group of medium butt sliders 27 (being in the example shown the seven carrying the needles 28b) which are situated in the middle of the short knitting butts in the bottom cylinder. The knitting butts of the boom sliders 27 are arranged in conventional manner, i.e., short butts in the heel half and long butts in the instep half. As the group of medium butt sliders 27 pass down the bolt cam 101 the cam moves right in so that all following sliders will be lowered. It remains in for one cylinder revolution only and as no yarn is being fed at the back feed, the needles will all be pressed off as their sliders engage this cam. Continuing from the stage where the group of medium butt sliders have passed down the cam 101 they now proceed below cam 102 until their transfer butts encounter cam 103. They are then lifted by this cam so that their knitting butts ride up cam 104 and raise their needles to clearing height. As there is no yarn on these needles at this stage it is necessary to open the latches by other means and in this example the upper cylinder sliders indicated at 36 in FIG. 3 are directed to a level where their noses shown at 105 (which are formed with chisel ends suitably shaped'for the purpose) encounter the needles whose sliders are progressing up the cam 104 and, by engagement of their chisel ends between the latches and hooks of the needles, open their latches.

The empty needles, led by the group 2811 whose sliders have medium butts continue at clearing height until they meet the needle lifter bolt cam 106 which is set to lift the medium butt group of sliders to a height above clearing height (being the height to which they are raised during the knitting of a heel pouch) while allowing the short butts to pass by it. The cam 106 is subsequently drawn right out to allow the long butts to pass by also at clearing height.

The state of affairs at this stage is as follows. Knitting of the final course of the finished sock is taking place at the main feed point A with sliders passing down the stitch cam 107. The sliders are then raised through the engagement of their transfer butts with cam 108 to raise the needles to clearing height as shown at (and at 28a in FIG. 2). Needles are being pressed-off at cam 101 (as the needles to the left of group 28a move fully downwards) and latches of empty needles are being opened as sliders are being raised by cam 104. Empty needles are approaching the main feed point A at clearing height led by the group of seven or so needles (whose sliders have medium knitting butts) at heel height.

As the group of needles at heel height (28b in FIG. 2) pass by the main feed point A the yarn is laid by the feeder (shown at 37 in FIG. 2) from the last needle to knit prior to this group outside the stems of the group 28b at heel height and into the hooks of the following empty needles. The stretch of yarn laid outside the stems of the group of seven or so needles at heel height is a more or less straight length of yarn being indicated at 38 in FIG. 2, and it is laid against the needles stems while the sinkers are out at the main feed point A. The sinkers are thrown out, as normally, approximately between the points X -X in FIG. 3. When the stretch of yarn just referred to reaches the point X and the sinkers move in to perform their normal knocking-over function, they will take the yarn 38 in between the needle stems. As the stretch of yarn is not nearly long enough to assume this sinuous form it breaks by the time three or four sinkers have moved in to the knock-over point. Now although this is the actual separating point of the two socks the yarn ends are both controlled by the sinkers.

The problem of refeeding the yarn to empty needles after pressing-off an individual article is completely solved by this method because the feeder remains in action. The actual releas of the finished sock and continued pick-up and knitting of the first course of the new sock will now be described by continuing the description from the instant of breaking the yarn.

The remaining knitted loops of the finished article still suspended from their needles extend between the point of breakage of the yarn and the needles at 28a pressing off their stitches as they pass down the back feed bolt cam 101. These remaining needles extend between the points Y-Y in FIG. 3 and as rotation of the needle cylinder continues these needles will also pass down cam 101 and press-off, thus releasing the finished article to be discharged by air flow through the tube 24.

The needles following the group of seven or so needles 2812 at heel height (which have the leading end of yarn for the new article trapped between their stems and the sinkers) all receive yarn in their hooks at the main feed point A. These needles had all pressed off earlier at the back feed bolt cam 101 and their latches had been opened as previously described so that they are ready to receive the yarn at the main feed point A. The butts of the group 28b at heel height pass above the back feed bolt cam 101 and the following needles after receiving the yarn are lowered by their butts passing down stitch cam 107 and are allowed to remain low, upthrow cam 108 being withdrawn, so that they do not clear their loops and are caused to pass the back feed station in this low position. The sinkers re-engage the yarn before the needles are raised again. Alternate needles are raised toclearing height by means of their pattern jacks lifting them so that their sliders pass up cam 104 and these alternate needles are then transferred by the patterning mechanism (not shown) to the top cylinder. The needles thus arrive at the main feed point A in a 1/1 set-out, i.e., alternate needles in the top cylinder and intermediate needles in the bottom cylinder with the yarn following a Zig-zig path from the hooks of the intermediate (bottom cylinder) needles to the alternate (top cylinder) needles where it is held behind their own latches. At the main feed point A the respective slider butts of these needles follow tracks 109 and 110. It should be remembered that there are no actual knitted loops on these needles as they enter the main feed station A, and the yarn merely lies in a zig-zag path from needle to needle.

As the needles pass through the feeding station the sliders of the rib needles follow track 110 and are raised by stitch cam 111. Although there is only one yarn on the needles and no stitch yet, a good feed is ensured because the yarn lies in the hooks of the plain needles whose sliders are in track 109 and behind the latches of the rib needles which are held open by the latchguard and the rib latches are closed by this yarn on to the new yarn. Knitting takes place on rib needles only. The rib clearing bolt 112 is withdrawn so that the newly formed rib loops are not cleared at this point but are kept at a high level to retain the loops on the needles as they pass the back feed point. The plain needles remain low at the back feed (cam 108 being withdrawn) and the rib depressor 113 at the back feed lowers the rib loops so that the sinkers move in over the yarn. The plain needles are then all raised up the clearing cam 104 and their sliders follow track 114 to cause them to knit at the main feed A.

If a welt is required (and it is not necessary to have one with this make-up) the welt bolt is withdrawn at this point so that the formation of the welt starts immediately.

If it is desired to incorporate an elastic yarn in the top of the sock it may be introduced to a few needles knitting 1/1 rib just before the start of the welt. The elastic yarn is actually fed to the needle of the first slider following the aforementioned group of seven or so medium butt sliders carrying the needles 28b in the middle of the short knitting butts.

The group of sliders 36 in the top cylinder immediately above this group have long butts to allow the welt bolt to be withdrawn at the commencement of the welt. By extending this group of long butts a few needles further than the group of medium butts in the bottom cylinder these few needles will knit 1/1 at the main feed to lock the start of the elastic yarn and will then enter the welt track a course later than normal.

It should be emphasized that the needle selection for the make-up courses desc-ribed in carrying out this invention is given by way of example only. The method of parting the yarn du-ring the process of knitting, to divide the articles, may be used with other methods of commencing articles and is not in any way restricted by the example given.

What I claim is:

1. A method of knitting a succession of tubular articles on a circular knitting machine comprising the steps of (a) pressing off from the needles each article on its completion, (b) commencing setting up a fresh course to start a succeeding article during pressing off of the preceding article, with a portion of yarn temporarily joining the completed and newly commenced articles, and (c) severing the joining yarn before the pressing off of the preceding article has been completed.

2. A method according to claim 1 wherein the severing of the joining yarn between successive articles occurs in a short length of yarn laid across the stems of a group of needles immediately beyond the last needles holding loops of the preceding article.

3. A method according to claim 2 wherein the severing of the joining yarn takes place after the yarn has been taken into the hooks of needles succeeding the group across the stems of which the joining yarn is laid and whilst the joining yarn is held between the needles into the hooks of which it has been taken and those needles still holding loops of the preceding article.

4. A method according to claim 1 in which the severing of the yarn between succeeding articles is effected by subjecting the yarn to local strain to fracture it.

5. A method according to claim 4 wherein the localised strain for fracturing the yarn is produced by causing at the appropriate time elongation of the path of the yarn.

6. A circular knitting machine organised to knit a succession of tubular articles and having in combination with a needle cylinder equipped with needles and cam means for operating said needles, means to operate said cam means so as to press off each article from the needles as it is completed, means for feeding ya-rn extending from the end of a completed article into the hooks of the needles from which the preceding article has been pressed off to commence setting up fabric for a new article before the preceding article has been fully pressed off from the needles, and means for severing the yarn extending between the preceding article and the newly commenced article before the preceding article has been fully pressed off from the needles.

7. In a circular knitting machine organised to knit a succession of tubular articles, the combination comprising a needle cylinder, needles in said cylinder, cam means for operating said needles, yarn feeding means organised to feed yarn to the needles and to continue such feed of the yarn from a preceding article to a succeeding article, means for pressing off each article from the needles as it is completed, means effective on completion of an article and on commencement of a succeeding article to sever the yarn between the articles to separate them, and additional cam means for raising a small group of needles following the last ones holding a preceding article so that stems of such raised needles receive a portion of the yarn in readiness for severance.

8. A combination according to claim 7 comprising a sinker bed, sinkers in said bed and sinker operating means arranged to cause the sinkers co-operating with the small group of needles to engage the portion of yarn laid across the stems of said needles.

9. A combination according to claim 7 wherein the said additional cam means comprises a bolt cam to effect raising of the small group of needles to receive the portion of yarn between the articles and butts are associated with said needles for selective engagement by said bolt cam.

10. A combination according to claim 7 comprising an inside sinker ring mounted within the needle cylinder, inside sinkers mounted on said ring and sinker cams organised to move sinkers associated with the small group of needles to move them inwardly when said needles are raised to engage with the portion of yarn against the needle stems.

References Cited UNITED STATES PATENTS 1,285,096 11/1918 Fisher 66-147 1,691,887 11/1928 Matthews 66-107 2,385,056 9/1945 Bromley et a1. 66-107 2,398,785 4/1946 Grothey 66-107 2,498,096 2/1950 Schaefer 66-147 3,282,070 11/1966 Perkins 66-147 WM. CARTER REYNOLDS, Primary Examiner.

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