US2908154A - Yarn handling and severing mechanism for circular knitting machines and method - Google Patents

Description

Oct. 13, 1959 v. H. BUTLER 2,908,154

YARN HANDLING AND SEVERING MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHOD Filed March 14, 1958 s Sheets-Sheet 1 53 I36 I40 I3 is 4 n u 66 72 I I i 44 I 9Q l II I 8 46 m @7 36 as r 06/// I 5 50 l 'NVENTOR so I 6 I32 I 80 VAUGHN H.BUTLER I24 ATTORNEY 5 Oct. 13, 1 959 v, T R 2,908,154

YARN HANDLING AND SE RING MECHANISM FOR CIRCULAR KNITTING MA HINES METHOD Filed March 14, 1958 8 Sheets-Sheet 2 I 74, 66 I I FIG.5.

VAUGHN H. BUTLER BYW ATTORNEYS Oct. 13, 1959 v. BUTLER I YARN HANDLING AND SEVERING MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHOD 8 Sheets-Sheet 3 Filed March 14, 1958 FIG. 2

INVENTOR VAUGHN H.BUTLER {Mud ATTORNEYS Oct. 13, 1959 v, BUTLER 2,908,154

YARN HANDLING AND SEVERING MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHOD Filed March 14, 1958 8 Sheets-Sheet 4 I INVENTOR VAUGHN H. BUTLER ATTORNEY-5' Oct. 13, 1959 v. H. BUTLER I 2,903,154

YARN HANDLING AND SEVERING MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHOD Filed March 14, 1958 8 Sheets-Sheet 5 Flam. 1019.

ales

INVENTOR' VAUG HN H. BUT LER ATTORNEYS Oct. 13, 1959 v. H. BUTLER 2,908,154 YARN HANDLING AND SEVERING MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHOD v Filed March 14, 1958 I a Sheets-Sheet e INVENTOR VAUGHN H. BUTLER ATTORNEYS Oct. 13, 1959 v. H. BUTLER 2,908,154

YARN HANDLING AND SEVERING MECHANISM FOR CIRCULAR KNI OD T'I'ING MACHINES AND METH Filed March 14, 1958 8 Sheets-Sheet 7' ATTORNEYS Oct. 13, 1959 v. H. BUTLE R I 2,908,154

YARN HANDLING AND SE ERING MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHOD Filed March 14, 1958 a Sheets-Sheet a INVENTOR ATTORNEYS United States Patent Ofifice Z,%8,l54 Patented Oct. 13, 1959 Vaughn H. Bufler, Harriman, Tenm, assignor to Burlington Industries, Inc, Greensboro, N.C., a corporation of Delaware Application March 14, 1958, Serial No. 721,452

7 Claims. (Cl. 66140) This invention relates to circular knitting machines, and in particular to improved means and methods for handling and severing yarns on the dial caps of multiple feed knitting machines.

In the knitting of tubular articles such as seamless hosiery, frequent yarn changes are commonly effected in the course of the knitting cycle. In the case of hosiery, for example, the welt and leg may be knitted of different yarns, and heavier yarns are frequently employed in the heel and toe. At each yarn change, an inactive yarn is dropped into the needles for knitting and an active yarn is withdrawn from the knitting a few needles later. At least two yarn ends extend from the resulting yarn lap, and these are commonly severed so as to be an inch or two in length. Since yarn ends of such length are easily noticeable and unsightly, they must be removed, and this is usually done individually and manually during inspection. The yarn ends are clipped down to A or which is commercially satisfactory. The clipping operation is obviously time-consuming and expensive, and exposes the stockings to possibility of damage. In multiple feed knitting, more than two yarn ends extend from each yarn lap, whereby the clipping problem is magnified.

A principal object of the present invention is the provision of novel means and methods for positioning yarns over the dial caps of multiple feed machines for clipping, and automatically severing the yarns close to the fabric during yarn changes, with such reliability and control as to eliminate subsequent inspection and clipping of free ends. In accordance with the invention, a single yarn handling device and a single shear are provided and utilized to handle and clip yarns from at least two distinct feed stations. The invention also contemplates the close clipping of the ends of newly inserted and with drawn yarns from a plurality of feed stations, preferably with a single shear stroke.

Another object of the invention is the provision of improved suction means for tensioning and controlling yarnson the dial cap of the machine, and means for positive and precise control of the air flow. Particularly,

means are provided to terminate air flow in precisely timed relation with operation of the shear, and subsequent to the shearing operation. Delayed air fiow termination is accomplished by means distinct from the shear operating means. A related object is the provision of means for delayed shear operation, that is, for operation of the shear after movement of the main pattern drum has terminated and while the latter is at rest, and alternative means for operating the shear in time with movement of the main pattern drum. Further objects will be in part evident and in part pointed out hereinafter.

The invention and the novel features thereof may best be made clear from the following description and the accompanying drawings, in which:

Figure 1 is a top plan view of a preferred embodiment of the invention in operative association with related parts of a two feed knitting machine, with some parts removed for the sake of clarity;

of Figure 1, viewed from the bottom thereof;

Figure 3 is a side elevational view of the mechanism of Figure 1, substantially from the left hand side thereof;

Figure 4 is an elevational view, showing details of the novel yarn clamp of the present invention;

Figure 5 is a plan view of a portion of the dial cap, illustrating the novel guide element provided below the yarn handling device;

Figure dis a sectional View taken on the line 66 of Figure 5; 1

Figure 7 is an elevational view, partly broken away, illustrating the air control means of the present invention;

Figure 8 is an elevational view of the air valve operating, latching and tripping mechanism of Figure 7, on enlarged scale;

Figure 9 is a side elevational view, partly diagrammatic, of the shear operating mechanism;

Figure 10 is an elevational view of the mechanismof Figure 9, viewed from the left-hand side thereof; and Figures 11 to 16 are plan views sequentially illustrating the operation of the invention through a yarn change.

Referring to the drawings in detail, Figures 1, 2 and 3 illustrate a portion of a conventional multiple feed seamless hosiery machine, such as a 400 needle model AMF Scott & Williams two feed machine. 'As best shown in Figure 1, the latch ring 20 of the machine encloses two knitting stations, which for convenience may be identified as main knitting station 22 and auxiliary knitting station '24, the auxiliary station trailing the main knitting station by approximately 45 in the direction of cylinder rotation, counterclockwise as viewed in Figure .1. At the main knitting station are provided a plurality of yarn fingers which are individually retractable andfunction as interchangeable yarn feeds. The yarn fingers are pivotally mounted in the usual manner, and actuated in conventional manner by thrust bars maintained in con-- tact with the main pattern drum of the machine. While six or more yarn fingers are customarily provided, only two are illustrated. As shown in Figures 1 and 3, main knitting station yarn finger 26 is illustrated in active position, feeding yarn 28 to the needles 30, and yarn finger 32 is illustrated in inactive position, the inactive yarn 34 extending therefrom to the dial cap of the machine in usual manner.

At the auxiliary knitting station 24 are provided the yarn finger 36 in active position, feeding yarn 38 to the needles 30, and the yarn finger 42 in inactive position, with inactive yarn 44 extending therefrom. As will be understood, other active and inactive yarns may be present, but are unnecessary for an understanding of the present invention. The needles 30 are independently mounted in the rotary cylinder of the machine (not shown), and extending thereabove adjacent the periphery of the dial and the dial cap 46. The usual dial drive pinion 48 is mounted on the upper end of dial drive shaft 50, whichv serves to effect rotation of the dial and its transfer jacks in synchronism with the cylinder. All of the foregoing elements are conventional.

Mounted on the dial cap, at a position near the periphery thereof and trailing the auxiliary knitting station 24 by approximately is a yarn handlingdevice indi cated generally as 6%. The yarn handling device is of the type disclosed in my copending application, Serial No. 650,212, filed April 2, 1957, and functions inv similar manner, although in the present invention the yarn hanw dling device handles yarns from both the main and the auxiliary knitting stations. As disclosed in detail in my copending application referred to, the yarn handling device includes a block or housing 62, the block having a horizontal bore extending therethrough, an 'air pressure conduit 64 leading thereto, and an exhaust conduit 66 near the encirclingneedles 30 of the machine.

The block 62 houses a piston 72, which extends above the top of the block, below the pivotally mounted clamparm 74. Fromthe free end of clamp'arm 74'extends a downwardly directed extension 76, best shown in Figure aeosnsa 3. A branch passage 7 8 extends to the under surface 80' or the block 62, the under surface of theblock being spaced slightly from the dial cap 46. A guide post 82 extends downwardly from the block to therdial cap, adjacent the opening ofbranch passage 78. As described in detail in my copending application referred to, pressure air supplied to the yarn handling device through conduit 64 exhausts through conduit 66 and is eflective to induce air flow upwardly into branch passage 78, in other words, to create a vacuum inand below branch passage 78'. The pressure air is effective also'to elevate the piston 72 and to pivot theclamp arm 74 disposed there above, whereby the clamp 'arm extension 76' is elevated at all times when pressure air is supplied tothe device; Aswill be'understood, spring or other suitable means are provided tobias the free end of clamp arm 74 and its extension 76 downwardly at all times. Some of the pressure air also .passes through tube 68 and'its nozzle 7 0, creating a jet of air at this-point. i In accordance with the present invention, a novel-yarn clainp'90ismounted on-the dial cap on the leading side" of the yarn handling device, immediately adjacent thereto; The inner-end of the yarn'clamp, encloses a headed pin 92 extendingfrom-the'dial cap, and is movable with re.-- spect to said'pin, the upward movement thereof being limited h'owever, by the head '94; Substantially centrally' thereof, the'yarn clamp encloses a vertical guide pin 96, andasmall springi98 encircles the guide pin' 96 between: the yarn clamp and the dial cap, as shown in Figure 4: The spring 98 tends to elevate the yarnclamp, to the: maximum distance'p'ermitted by-the head 94 of pin 92. and the overlying adapter 100 through which the pressure conduit 64 enters the block62. Outwardly of the guide pin' 96 the yarn clamp extends below the bottom' 'of' clamp arm extension 7 6, and th'erebeyond the leadingiedge thereof isformed intoa forwardly curved portion1104.. A substantially V-shaped yarn guide 110,. which may:

4- 7 6 center on a stud 138 extending from the block 62. The opposite end of lever 136 is engaged by rod 140 to an operating lever 142, which in turn is pivotally mounted The disposition of the yarn handling device 60 and shear 120, as illustrated and described, necessitates relocation 1 of the: pin customarily I extending downwardly from a the r overhangingbracket' arm 'of the machine to the-dial cap 46, to preclude rotation of the dial cap 'and the ele ments mounted thereon. ,In accordance with the present invention, thistpin (not shownlmay be relocated-on a bracket extending from the overhanging bracket. arm,

j downwardly into the dial cap socket 146', shown in Figure 1.. I a v The air controlmechanism of the invention is illustrated in Figures 7' and 8.' As there'shown, a conven-' tional air valve 150 is mounted on a plate 152 which in turn is supported by aframe mounted bar 154,- adjacent the main timing drum 156 of the machine. The air valve 150'is provided'withaplunger;158, whichisinternally biased to outward valve closedposition. The valve is substantiallyT-shaped, and as Will be understood l a source of air'pressure is-connected-to one side thereof and'thefpressure conduit 64 extends=from the other side thereof to the yarn handling-device 60.-

A lever: arm 160is-pivotally mounted at 162 :on thebar 154, oneend-of the'lever ammbeing maintained-incontact with the timing 'drum l56 by a spring "164 suit ably engaged to the other end of the lever arm.- The lever armis in alignment with the head 1660f valve plunger 158, and may be foimed into a cam=surface 168 adapted to bear against the. valve plunger head.

Adjacent 'the'lever arm-162, arhand lever 170 is-piv-- otally mounted at- 162, the hand'lever-also being aligned with and "engaging. the valve'plunger'head 166,,and being formed in'tofan outwardly extending-tail172. A latch bracket 174' is fixed to the sideof hand. lever 170, and,

a suitably shaped latch 176extendslaterally therefrom.

be formed'of wire, extends from the base of pin 92, its

directly below the branch 'passage 73 and isinclined with'.

respect to the normal yarnpath. Conveniently, the guide element may be a section ofwire, suitably anchored into the dial cap as shown in Figure 6', and resting directly thereon. I

' Slightly-beyond the yarn handling device 60, and substantially=opposite themain knitting station 22,. is dis posed theyarn shear indicated generally as 120. The yarn shear is peripherally mounted, and of the type' dis? closed'in' my copending application referred to; Intheexemplary embodiment,. due to the skirted configuration of the'dial structure, thexfixed shear'blade 122 is disposed substantially in the slot 124, and the movableshear' blade 126 operates in conjunction therewith, pivotingat' 128. The skirt130 in theivicinity of theskirtslot'5124, is appropriately bevelled, 'as at 132';

Spring 178- extends from the latch 176 to the valve mounting structure, whereby the latch and theassociatedhand lever are maintained'in contact, with valve plunger I head 166, although with insufficient pressure to depress the valve'plunger '158 and openthevalve.

A latch arm 180-is: pivotally mounted at 182 on the, valve mounting structure, and extends below-the latch 176; The latch arm 180 is formed'into; a latch engaging shoulder 184 and outwardly thereof into an upwardly- V ofisetriding surface 186, and a;;spring 188- biases the:

latch arm 180- upwardly at all contact with the latch 176i Referring to Figure 7, 190 is a rotary shaft of the. machine which rotates 'at' one-fourth the speed -of the needle cylinder. The shaft 190 is'provided with a boss 1'92, and a rocker arm 194 is pivotally mounted there times to maintain it in above at 196. Spring or other suitable meansfare pro vided to maintain the. associated end of rocker arm 194' in contact withthe boss 192. A rackingpawl 198 extends from the other end of rocker arm 194: into. contactwith' the graduating cam of: the machine, which is not shown but which-is in alignmentwith the timing .156. Opposed cams 200 areprovided on the periphery of boss 192, adapted "to-engage and rock arn1-1-94 periodically.

The shaft -1'90;=boss 1 92, rockeram 194-, ran-:ki'n'g pawl 198, and thecams 200 are standard elements of the model AMF machine with-which the instant invention is illustrated-. In applying the invention tothis machine, the rocker arm 194 may conveniently be extended, as at", 202, and a 'rigi'd'rod 204provided between the rocker arm extension 202 and side'pad 2'06 mounted on the'latch arm 180. In: this manner, means are-conveniently pro vided for periodically depressingrtlie'latch arm; and it a will beevident that; equivalent tripnieans may befpro- 'Themovable shear blade'126 is engagedby'rod 13410 one end orlever' 136,which ispivo'tally'm'ounted nearit's vided-inassocia-tion with any other moving part ofthemachine; *The timing" provided with cams 208; in alignment with lever arm l 60g-the cams being --'adaptedl to displace the associated end of the lever arm away from the drum in the usual manner. I

To utilizea single shear to cut all yarns of the exemplary two feed machine, it is necessary to provide for normal shear operation in time with movement of the timing drum, and also to provide alternatively for delayed operation of the shear, that is for shear operation while the drum is stationary. In the model AMF machine, makeup is accomplished with a series of intermittent and brief auxiliary drum movements, which are long enough to permit dropping yarns in or taking yarns out at both stations, but not long enough to permit the yarns to reach the position of yarn shear 120. It is accordingly necessary to provide delayed action shearing during the makeup. Alternative means for shear operation are illustrated in Figures 9 and 10.

As shown in Figure 9, the operating lever 142 which is engaged to the movable shear blade 126 through rod 140 is engaged and actuated in normal manner by a thrust rod 210, which is maintained in contact with the timing drum 156 and elevated periodically by drum cams 212. The thrust rod 210 passes througha guiding passage in the guide bar 214, and a spring extending from the guide bar to the thrust rod, urges it downwardly into contact with the timing drtun. As will be understood, periodic movement of the timing drum in clockwise direction, as viewed in Figure 9, brings successive cams 212 under the thrust rod 210 and elevates the thrust rod to the top of a cam, the elevated position of the thrust rod being indicated in dotted lines in Figure 9. The upward movement of the thrust rod rocks the operating lever 142 in clockwise direction, moving the rod 140 downwardly and thereby opening the shear. As further movement of the timing drum carries the cam 212 out from under the thrust rod 210, the thrust rod returns to normal position riding the drum, permitting the shear to close. As disclosed in my copending application referred to, the trailing end of the shear operating cam 212 may be stepped or sloped, to permit closing of the shear over a space of time corresponding to the passage of several needles, for a purpose presently evident.

As illustrated in Figure 10, the end of operating lever 142 over the thrust rods may be provided with a transverse pad 216, whereby the operating lever is adapted to be engagedby a thrust rod 218, as well as by the thrust rod 210. In the drawings, the thrust rods 210 and 218 are relatively widely spaced for the purpose of clarity of illustration, but it will be understood that in practice the thrust rods may be closely adjacent, and in place of the pad 216, two adjoining operating levers may be tied together to function as one, under the impetus of either associated thrust rod.

The thrust rod 218 is utilized to effect shear closing after short auxiliary drum movements have terminated, as during makeup. As shown .in Figure 10, the guide bar 214, behind thrust rod 218, is cut away or slotted at 220, to permit rearward movement of the thrust bar, and an additional spring 222 extends from thrust rod 218 forwardly to the guide bar 214, to urge thrust rod 218 forwardly and maintain it when permitted in normal position. A collar 224 is provided on the rotary shaft 190 in alignment with the thrust rod 218, the collar having opposed convex cams 226 thereon, and a cam 228 is provided on the forward edge of thrust rod 218 in the vicinity of collar 224. The cams 226 and 228 are of such size and disposition that when the thrust rod 218 is in normal position, directly behind the solid line position of thrust rod 216 illustrated in Figure 9, the collar 224 and its cams 226 rotate without striking the thrust rod cam 228. Shear operating cams 230' are provided on the timing drum in alignment with the thrustrod 218, and it will be understood that a brief movement of the timing drum is adequate to elevate the thrust rod 218 onto a cam 230 and into shear opening position. The timing drum movementmay then, terminate in such relationship. Elevation of the thrust rod 218, however, displaces its cam 228' into the path of the cams 226, so that a brief interval after elevation of the thrust rod and termination of the timing drum movement, one or the other of cams 226 will strike the thrust rod cam 228, and displace the thrust rod 218 rearwardly, to the dotted line position 218 shown in Figure 9. This rearward movement of the thrust rod 218 is permitted by slot 226 and resisted by spring 222, which is effective on subsequent movement of the timing drum to restore the thrust rod to normal position. As will be understood, rearward displacement of the thrust rod 218 is eifective to drop its bottom end off the cam 230 therebelow, whereby the thrust rod drops into contact with the drum (although at position rearward of normal) and permits the shear to close. In this manner, a brief interval of time between termination of the timing drum movement and shear closing is provided.

Function and operation of the invention will now be described in detail, in connection with an ordinary yarn change during two feed knitting. Normal operation of the machine is illustrated in Figure 1, wherein the yarn fingers 26 and 36 are active, feeding yarns 28 and 38 directly to the needles at their respective knitting stations. From the retracted finger 32 at main knitting station 22, the inactive yarn 34 extends under yarn guide 110, around yarn guide post 114, under yarn clamp 96, alongside guide post 82 and upwardly into branch passage 78 of the yarn handling device. From retracted yarn finger 42 at the auxiliary knitting station 24, inactive yarn44 extends under yarn clamp 90, alongside guide post 82, and upwardly into the branch passage 78. As will be understood, the ends of inactive yarns 34 and 44 and all other inactive yarns extend through the yarn handling device block 62 and into the exhaust conduit 66.

During normal operation of the device as described, the lever arm 168 of the air control mechanism is riding a cam 208 of the timing drum 156, and latch 176 associated with the hand lever 170 is riding the surface 186 of the latch arm 180. The plunger 158 of valve is extended, whereby the valve is closed and air is cut off from the yarn handling device 68. It will be understood that periodic depression of rod 284 by the movement of rocker arm 194 (Figure 7) merely depresses the latch arm 180, the latch arm being returned to the position illustrated in Figure 8 after each depression by its spring 188. The yarn shear 120 during normal operation is closed, both thrust rods 216 and 218 riding the surface of drum 156, the end of operating lever 142 engaged to the shear being in elevated position.

When the machine comes to a yarn change, initially the yarn finger 32 is dropped to active position at the main knitting station 22, whereby the formerly inactive yarn 34 is taken by the needles, the first needle to knit this yarn being indicated in Figure 11 as 30'. Substantially simultaneously, the drum movement effecting the yarn change carries the engaged cam 28% out from under the lever arm of the air control mechanism, permitting spring 164 to force the opposite end of the lever arm 168 against the timing drum 156. This movement of the lever arm 160 causes its cam surface 168 to depress the head 166 of the valve plunger 158, opening valve 150, whereupon pressure air flows through conduit 64 to yarn handling device. As described in my copending application referred to, access of pressure air to the yarn handling device 60 induces suction and air flow upwardly into the branch passage 78,and a high velocity air flow outwardly through exhaust conduit 66. Theresultant suction and air flow engages the ends of the inactive yarns, particularly yarns 34 and 44, and tensions these yarns, assuring positive yarn laps;

Simultaneously,the pressure air. elevates piston 72 and the;-assoc1ated.clamptarm ,74, w hereby the clamp'arm e osgrsas extension 7 6 rises} from the clamp 90, releasing .the'yarns extending'therebelow. The small: spring 98 below the. y-a'r'n' cla'mp 90, willbe understood, cooperates to elevate the y arn clamp a shortrdistance' from the dial cap surface; The access of pressureair toithe yarn=handling device "also causes-"a jet of air to issue from nozzle 70 of the tube-68, this air, flow having no function at this stage'ofthe operation. a i a When valve 150 is opened by the lever arm160, the hand lever l70=follows the valve plunger head 166,. by action-of spring178, displacing the associated latch 176 totheright asxviewedin 'Figure-8, beyondthe shoulder 184 ofrlatcharmf180; When this occurs, spring 188 elevates the latch arrn'-1'80-'to latchingposition, retaining th'e' hand lever 1170 in. valve opening-position. Periodic depression of rodt204 will lower the latch arm 180 out ofziengagement with latch: 176, :but so long as the valve 150 ismaintained open aby lever arm .160,' the hand lever 170 will'remain in place against the valve plunger'head 166', in inward position, and willv be re-engaged by" the shoulderz'l84; of'ithe latch'armr 180 upon its return to elevated. position.

Simultaneously, or briefly thereafter, a drum cam 212 passes under and elevates the thrustrod'210 (Figure 9), rocking the operatinglever-14Z1to open yarn shear 120; As seen in Figures l, 2 and 3, downward movement of the-associated end of operating lever 142 depresses rod 150 to rotate lever'136, and the other end of lever 136 acts throughrod 134'to elevate the movableshear blade 126-about its pivot128. The shear remains open through out the remainder of the yarn change, closing as one of the final movements thereof.

Momentarily after the yarn 34 is'dropped into the needles at the main knitting station 22, the previously active yarn 2 8 is withdrawn therefrom, byretraction of its yarn finger Z6. Desirably, the previously active yarnis withdrawn 10 or needles after the hitherto inactive yarn is;inserted,'providing ayarn lap of about one-half inch. Some adjustment ofthe yarn finger operating'cams of the'machinemay be required toachieve short yarn lapsof this order, the'machine normally providing longer yarnlaps in 'orderto avoid misses. In operation of the present invention, no yarn laps are missed, even thoughthe laps arelessthan one-half inch. Figure 12 illustrates the relationship of the elements immediately after yarn '28 has been withdrawn from knitting by retraction of finger 2 6. Itwillbe noted that the newly inserted yarn 34 has been carried a short distance around the needle circle by'needle 30", and the yarn end has been partially withdrawn from under the yarn guide 110. The resultant slack in the end of yarn 34 is taken up by the yarn handling device60, which takes up the yarn end as permitted.

When needle 30', the first needle to take the yarn 34 newly inserted. at the main knitting station, reaches the auxiliary knitting" station 24, the inactive yarn 44' is dropped into theknitting by itsyarn finger 42, the ma: chine being adjusted to drop this yarn in, at or close to the needle 30'. Figure 13 illustrates the relationship of the yarns and yarn fingers immediately after yarn finger 42 has been-dropped to active position, and the yarn 44 inserted into the needlesfor knitting. As shown, the yarn- 44 has been dropped into the knitting two needles behind needle 30. It will be noted that at this point theend'of'yarn 34 has been. carried by needle 30 completely out fromunder yarn guide 110, and through thisfmovement the yarn endis tensioned and slack there". in taken up by yarn handling device, as previously de-. scribed. It will be further noted that the trailing end of the 'yarn28- newly withdrawn at the. main knitting station, extending from the needles to :the now-retracted yarn finger. 26, .isin position :to be .guided below the yarn guide Shortly after :the" yarn .544 .1 is dropped intothe knitting ahfllflg amdliary station, the yarn- 383 withdrawnfrom iliary knittingstationj-the yarni-handlingdevice maintaine ingtension anditakingeup-theslack therein; :The yarn. 28: withdrawn at the. main; knitting station has by: this timeipassed undenthe'outer arms. 112 ofv the yarn; guide: 1 10. 1

Figure 15 illustrates the I relationship of- "the. yarns: whenzthe needle 30? has-reached a. position substantially opposite-theyarn handling devicer60; At thisi-timethe. yarn'..2 8 withdrawnt'fromthe knitting at the main akn'itting station; is engageddngthe V. of. yarn :guide' 110, wrapped slightly around: the 5 guide. post 114; ,and has passed under the outer; endrofqitheiyarn clamp'fll. The yarnc-38twith drawn. from'fthe rknitting. at: the auxiliary knitting :station ZAwhaspassed-under; theouter end of yarn clamp 90:- The curved outerportion- 104- of they .yarn clamp insures that the yarns drawn therepast by the needles go under the-yam .clarnp. The ends extending from. the newly,

inserted; yarns 34 land: 4-4 are. disposed substantially. radially .of'thebranchfpassage 78 of the yarn='handling de'vice,.andzall slack in: the: freeyarn ends haslbeen' taken up in' 'the. branchrpassageflS andthe'exhaust conduitw66; whereby efi'ective .tensionismaintained'.on these yarns; It: will be noted" thatv the s'yarn guide and guide post 114 tend tozseparatezyarns.extendingrfrornv retracted yam fingers;ofthe-main knitting station-from yarns extending from; retractedEyarn fingers of the auxiliary knittingsta-z tion; 'rIn actual operation; inactive. yarns from the: re spective knitting stations are thereby -maintainedl in sepi arated bundles,.passing under the yarn clamp-'90 side? by side; a

Figure. 16- illustrates the relationship 0f the yarns and other elements when" the needle 30' has reached a positionv close. to the. pivotal axis of the yarn shear 120. In movin'gzfrom the position of: Figure. 15. to the positiorrof the position of: Figure 16,: the yarn ends 34 and44aare withdrawn-from the-branchrpassage 78, against the-ten: sioningresistance of air movement. The yarn 28' newly with drawn at the. main knitting 'stationextends under:

arm 110, around :guide .post 114-, under yarn clamp; 90, alongside the guidepost8'2 below the block 62,.and then below the branch passage. 78 to the last needle to take this yarn. The yarn;38- newly withdrawn at the auxiliary knitting stationzextends under 'the yarn clamp 90, alongsidethe guide post. 82,.and below branch passage 78 tothe last needle to take; this yarn. As described in my copending application previously referred to, the suction efiect. below branchpassage 78 of the yarn handling deviceiseffective to engage and lift the yarns 28 'and 38= exten'dingthereunder, to tension-these yarns. This func tionis enhanced by'the' guide element 116 disposed'below branch passage '78,- which serves to raise these yarns slightly from the surface of the dial cap. It has been tound'that the newly withdrawn yarns, due to the" influence of'lubricant orother factor, maytend'to adhere to the surface of'the dial cap and resist the tensioning efiect of the air flow below the branch passage. The novel guide-element-1 16 prevents this, separating these yarns from the dial cap'as they are drawn under the yarn tensioning device to insure that the yarns are suitably engaged and tensioned.

Theair blast issuing fromnozzle 70 is effective atthis'tir'ne to belly out the 'yarns where they extendinwardly from the needles. This airb'last sweeps across the peripheral portion ofthe dial cap-in the vicinity ofthe shear; in thes'direction of'needlef rotation, engagingthe sufficiently to insure .that they extend substantially radially inwardly from'the needles. The blast effect of the nozzle is balanced by the restraining suction effect of the yarn handling mechanism on the 'yarns, with the net result that the yarns assume the relative positions shear to the needles, due to the inclination of the yarns.

The effect of the air blast on the yarns, then, is to position them for shearing 'in such manner that the cut ends remaining on the fabric are of absolute minimum length.

Shearoperation is .timed to take place at about the time when the yarns are in the position of Figure 16.

Desirably, closing of the shear is initiated slightly before the needle 30' reaches the position of Figure 16 At this point, the cam 212 passes out from under the thrust rod 210 (Figure 9) permitting the operating lever 142 to rotate counterclockwise as viewed, and to close the shear. Since the last needle to, take the auxiliary knitting station yarn 38 may trail the needle 30 by an inch or more, the difficulty of cutting all four yams with a single shear stroke will be apparent. The size of the shear blades have, of course, a practical limit, andthe yarn 38 may not be positioned for shearing when the yarn 34 reaches the last possible position for shearing. For this reason, it is desirable to close the shear gradually over a'discrete time interval. plished by suitably sloping the trailing end of the shear operating cam 212, or providing a stepped configuration therein. This results in relatively gradual closing of the'shear, whereby the movable shear blade 126 pivots to closed position over an appreciable period of time corresponding to the passage of several needles. Shear closing may in this manner be timed to-initiate shearing immediately prior to the point illustrated in Figure 16, and to complete the shear stroke a few needles after the momentary position illustrated in Figure 16, thereby insuring that all four yarns are sheared in a single stroke, leaving cut ends on the fabric of less than one-hallf inch inlength. v V f if After shearing, the severed ends from yarns 34 and 44'.are picked up through branch passage 78 and exhausted through exhaust conduit 66 of the yarn handling device, to a screen receptacle or the like. The cut ends of the newly withdrawn yarns 28 and 38, extending from the now retracted yarn fingers 26 and 36,,are engagedin the branch passage 78 and sucked up therethrough into the yarn handling device and its exhaust conduit 66, to the former position of yarns 34 and 44.

Finally, at the end of the drum movement effecting the yarn change, a cam 208 passes under the lever arm 160 of the air control mechanism (Figures 7 and 8) and displaces the lever arm to the position shown in Figure 8. The valve 150 is prevented from closing immediately, its plunger 158 being held in by the hand lever 170, the associated latch 176 being engaged against the shoulder 184 of latch arm 180. That is, upon retraction of the lever arm 160 therefrom, the valve is momentarily latched in open position by hand lever 170 and latch arm 180.

Briefly thereafter, the rocker arm 194 is displaced by one or the other of cams 200, displacing the rod 204 and the engaged latch arm 180 downwardly. The latch 176 is in this manner tripped, and the valve 150 is permitted to close, its plunger 158 and its head 166 moving outwardly and returning the hand lever 170 to the position illustrated in Figure 8. In this manner, air flow to the yarn handling device may be maintained slightly beyond the duration of the drum movement, insuring that the This may be conveniently"a'ccom-" shearing operation is completed and that all yarns are engaged, cleared, and tensioned before the air flow is cut off. I

The closing of valve 150, of course, terminates the flow of air through nozzle 70, and permits the piston 72 to retract, whereby the clamp arm 74 may be rotated by its spring to bring its extension 76 into firm contact with yarn clamp 90, whereby all yarns extending thereunder are mechanically and positively clamped. The

clamp pressure persists until the next yarn change,

when pressure air is again admitted to the yarn handling device.

The hand lever is useful for manual opening of the valve 150, to permit air flow. An attendant may at any time, in threading or adjusting the machine or the like, lift the hand lever tail 172 to open the valve.

The foregoing completes the description of an ordi-- nary yarn change during two feed knitting. As previously indicated, makeup on the illustrative machine is'efiected by drum movements of very short duration. I-n starting a stocking, for example, yarns may be dropped in at both knitting stations, but the drum movement tenninates before these yarns reach the position of shear 120. For this and similar operations in makeup or otherwise, the shear may be actuated by the thrust rod 218. As previously described, a brief movement of the timing drum 1 suffices to move a cam 230 under and to elevate the thrust rod 218 =and open the shear. Shortly thereafter, the thrust rod is rearwardly displaced and knocked on the cam by the action of shaft 190, permitting the shear to close. The time interval thus provided is sufiicient to permit the yarns to reach the position of the shear, although the timing drum movement has terminated previously. Either alternative method of operating the yarn shear may be employed at any stage in the knitting cycle, as they operate independently of each other.

It -will be thus seen that there has been provided by this invention apparatus and methods in which the various objects hereinbefore set forth, together with many prac tical advantages, are successfully achieved. .As various possible embodiments may be made of the several features of the above invention, all without departing from the scope thereof, it is to be understood that all matter here-.

top of said cylinder, a first group of individually retractable yarn feeds, a second group of individually retractable yarn feeds angularly spaced from said first yarn feed group in the direction of cylinder rotation, a timing drum controlling the movement of said yarn feeds, a shear disposed peripherally of said dial cap at a point angularly spaced from said second yarn feed group in the direction of cylinder rotation, means actuated by said drum for opening said shear, means for closing said shear when said drum is stationary, a yarn handling device mounted above said dial cap between said second yann feed group and said shear, an air line leading to said yarn handling device, a valve in said air line, means actuated by said drum for opening said valve, and means for closing said valve when said drum is stationary.

2. A circular knitting machine as defined in claim 1, wherein said yarn handling device includes a housing, a horizontal bore extending through said housing, said air line communicating with one end of said bore, an exhaust conduit communicating with the other end of said bore, and a branch passage extending downwardly from an intermediate section of said bore and opening above said dial cap.

3. In a circular knitting machine, a dial cap and a yarn handling device mounted above said dial cap, said yarn handling device including a housing, a horizontal conduit communicating with the other end of said bore, aebrancmpassage; extending downwardly froman intermediate section of said bore and opening above said,dialt cap,;-a-;yarn clamp mounted on said-dial cap adjacent saidhousing, a-clarnp arm -pivotally mounted on saidhousing; for; vertical, movement, resilient-v means urging 7 said: clamp: arm: downwardly .into 1 contact-- with said yarn; clamp, resilient meansbetweemsaid yarn clamp-and'saiddial cap ad'apted; to elevate said; yarn clamp a limited distance when said clamp arm is elevated, at verticaLbore,

inrsaidi housing, a-piston in said verticalbore, saidiv piston 7 engagingsaidclamp, arm'wherebyupward movement oft-- said; piston Willelevate said clarnp arm, and a-passageim said housing providing communication between said:pres-. sure conduit and the bottom of said vertical bore.

4;- I11,-the operation of a. circular knitting machine,

havinga rotary cylinder withindependent needle s, ,a dialcap,;:mounted adjacent the. top of, said cylinder, a first group of; individually retractableyarn feeds,,and .a sec ondrgr oup of individually retractable yarn feeds angularly, spaced from said-firstgroupin the direction-off cylin- .7 der rotation, the method-comprising thesteps of applyi-ng tension toyarns extending from both yarnfeed groups over 'Sal da dial cap by suctionappliedlat a-common point, and inserting said yarns into the needlestor knittingwhile,

so tensioned;

' 5. In--the operation; of a, circularknitting machine, having a rotary cylinder with" independent needles, a dial cap. mounted adjacent thetop of; said cylinder,,,a;;first- 73 group of individually retractable yarn-feeds, andr. ond group of individually retractable yarn, feeds angu:

lar-ly spaced from said first group in the .direction ofcylin del -rotation, the method comprising the steps of removingyarns from active knitting by retraction of a-yarnfeed1 of each of'said yarn feed groups, whereby saidiwithdrawnyarns are carried by the last needle to-knit each means of said suction.

6; In the operation ofa circular knitting machine, having a rotary cylinder with independent needles, adial" cap, mountedv adjacent the top ofsaid cylinder, a, first group of individually retractable yarn feeds, a second group of individually retractable yarn feeds vangularly spaced from. said firstgroup in the direction of cylinder 7 rotation,.and yarn severing means disposed peripherally of said: dial cap. at, a point angularly spaced fromsaid saidyarn Eseveringmeans in the direction ,ofjcylinderro '12 second yarn feedgroupjn the directionof cylindifirotation, the method comprising the steps; of applying; sion to inactive yarnends extendingfrom both ,fe groups oversaiddial cap by suctionapplied ,to a common pointtrailing said second. yarn feedfgr'oup and leading tion, inserting inactive yarnsfrom each ,of saidyarnfeed; groups while so tensionedinto the needles for knitting}, withdrawing yarns from active knitting by ret action, of; a yarn' teed of each. ofvsaid yarnfeed groups,jwherebv'.

'said withdrawn yarns are carried by the. lastneedleto,

kniteach yarn: aroundsaid cylinder and over said,dial,, cap, applying tension tosaid; withdrawnyar'nsrby. suction, applied atsaid commonpoint, severing allot, said yarns, close. to the fabricwhile sotensioned, removinglthesev-i ered newly inserted yarn endsby-means of saidlsuction, and engaging 'the severed v withdrawn ends; bymeansiofl said suction. i f a i 7 In the operation of a circular. knitting machine, havingarotary cylinder with independentineedles, a} cap mounted adjacent the top. of said cylinder a group ,of aindividually retractable yarn feeds,v a, second group of individually retractable yarn feeds spaced-from:- saidfirst groupiin th e direction of cylinder. rotation, and, a shear disposed-peripherally of said. dialv capat. a,point;. angularly spacedfrom said second-yarn feed group in theI directionrof cylinder rotation, the methodcornprising; the, steps of applying tension to inactive yarn .ends'extending,

from both yarnfeed groups over said dialcap atapointI;

References Cited in the file of this patent V UNITED STATES PATENTS 1 1,352,079 Miller Sept. 7; 1920" 1,359,250 Houseman Nov. 16,1920 1,865,710 Smith July-5, 1932 2,180,707 Houseman Nov. 21,1939 2,287,131 Redeen 'June 23,-1942 2,551,385 Miller May 1, -1 2,824,436 Stack et a1. Feb; 25;1958

, FOREIGN PATENTS 503,418 Germany Ju1y:24, .1930s

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