US2940285A - Yarn feeding and changing mechanism for circular knitting machines - Google Patents

Description

June 14, 1960 A. P. SAUNDERS 2,940,285

YARN FEEDING AND CHANGING MECHANISM FOR CIRCULAR KNITTING MACHINES Filed Oct. 4. 1957 5 Sheets-Sheet 1 l/VVE/VTOR ALFBED PERCY SAUNDERS ATTORNEYS June 14, 1960 A. P. SAUNDERS 2,940,285

YARN FEEDING AND CHANGING MECHANISM FOR CIRCULAR KNITTING MACHINES ALFRED PERCY SAUNDERS cz is June 14, 1960 A. P. SAUNDERS 2,940,285

YARN FEEDING AND CHANGING MECHANISM FOR CIRCULAR KNITTING MACHINES Filed Oct. 4, 1957 5 Sheets-Sheet 5 ALFRED PERCY SAUNDERS roRA/H June 14, 1960 A. P. SAUNDERS YARN FEEDING AND CHANGING MECHANISM FOR CIRCULAR KNITTING MACHINES 5 Sheets-Sheet 4 Filed 0cr.. 4, 1957 ALFREgfLERCY SAUNDERS 73.. w 3

ATTORNEY June 14, 1960 A. P. SAUNDERS 2,940,235

YARN FEEDING AND CHANGING MECHANISM FOR CIRCULAR KNITTING MACHINES Filed Oct. 4, 195'? 5 Sheets-Sheet 5 ALFRED PERCY SAUNDERS United States Patent YARN FEEDING AND CHANGING MECHANiSll/I FOR CIRCULAR KNITTING MACHINES Alfred Percy Saunders, Leicester, England, assignor to Wildt Mellor Bromley Limited, Leicester, England, a British company This invention relates to yarn feeding and changing mechanism for circular knitting machines of the cylinder and dial type, and has reference particularly to yarn feeding and changing mechanism of the kind including a plurality of yarn guiding feeders each of which has associated therewith an individual yarn placing element, and wherein the said elements are operable selectively and each adapted, when so operated, not only to contact and move the companion yarn feeder from a non-feeding position adjacent to yarn trapping and severing means into a feeding position at which a yarn is favourably disposed by the feeder for introduction to needles of one of the two sets in the machine, but also to act on the yarn so disposed and thereby displace it in a radially inward direction suchwise as to efiect such introduction.

The invention may be applied to cylinder and dial machines of the rotary cam box type, i.e. of the type wherein the cylinder and the dial are stationary whereas the cylinder cam box and the dial cam plate furnished with the cams necessary for actuating the sets of cylinder and dial needles, revolves together.

There is, however, no limitation in this respect since the invention may also be applied to cylinder and dial machines wherein the cylinder cam box and dial cam plate are stationary and the cylinder and the dial rotate together.

The object of the present invention is to provide general improvements in the construction, operation and control of a yarn feeding and changing mechanism of the kind concerned as will be hereinafter described.

A particular aim is to enable the improved mechanism to feed to the needles difierent types of yarn or thread such as fine nylon thread, elastic yarn, yarns of wool and many other combinations, and efiiciently to effect changes as from a yarn or thread of one character to a yarn or thread having quite different characteristics.

The invention may advantageously be embodied in a horizontal striping attachment.

In the improved yarn feeding and changing mechanism constituting this invention there is an independent yarn trapping and severing unit to each yarn feeder and associated yarn placing element, and for actuating each such element and also a member for operating the corresponding individual trapper there is provided a common actuator which is adapted, when selected and moved to initiate introduction of a yarn to appropriate needles, to be advanced in two separate and defined stages, viz a first stage during which the common actuator moves the yarn placing element into its operative position and, in so doing, first causes the said element to contact the companion yarn feeder and displace it from its nonfeeding to its feeding position, and a second stage at which the corresponding trapper operating member is operated suchwise as to open the relevant trapper and thereby release the yarn introduced to the needles.

For the sake of simplicity in the following further de- 7 2 scription and in the appended claims the yarn placin elements will be referred to as yarn placers. As will be appreciated, there is a plurality of the common actuators, one to each yarn feeder and corresponding yarn placer and independent trapping and severing. unit, and these actuators are adapted to be selectively operated, through the medium of control connections of any suitable character at the dictates of timing mechanism.

Each common actuator may advantageously be suitably biassed, e.g. by a spring, towards its normal inoperative, i.e. un-selected, position and arranged to be advanced against the biassing means. In this regard, an individual spring-influenced check pawl or detent may be provided for co-operation with spaced formations in.

each actuator, these formations, two in number, serving to define the two separate stages in the advance of the actuator to its fully operative position. That is to say, engagement of the check pawl or detent into the first of the two formations will determine and define the first stage of the advance of the actuator to effect introduction of the relevant yarn to the needles of the appropriate set, whereas the second stage of such advance to open the corresponding trapper and release the said yarn will be determined and defined by the engagement of the check pawl or detent in the second formation. When engaged in said second formation, the check pawl or detent functions to hold the actuator fully forward with the corresponding yarn feeder in its feeding position which latter is maintained for as long as the yarn is' required to be fed to the needles. For eifecting withdrawal of such yarn feeder from knitting as, for instance, at a yarn change, the check pawl or detent is moved under suitable control against the spring action influencing it, as a consequence of which the common actuator is released for rapid return to its inoperative position under the action of the aforementioned biassing means. Simultaneously with this return, the corresponding yarn placer and the associated yarn feeder, conveniently influenced by a common spring, are retracted to their inoperative positions.

In accordance with a feature of the invention, provision is made for lost motion between each yarn placer and the corresponding actuator during the second stage of advance of the latter. The purpose of this is, of course, to enable a yarn feeder and the associated yarn placer to remain stationary in their feeding positions whilst the actuator is moving forward to complete .its second stage of advance at which point it efifects actuation of the trapper operating member and opening of the trapper to release the newly introduced yarn; In this way the said yarn is enabled to be safely taken and knit-ted by a few (say two or more) of the needles of the appropriate set before the yarn is released from .the trapper. According to a further feature of the invention, an individual spring-influenced check detent, separate and vdistinct from the corresponding actuator check pawl or detent, is provided in conjunction with each trapper operat ing member for the purpose of maintaining the latter in the position to which it is moved by the said actuator during the second stage of the advance thereof. Thus, the check detent functioning in conjunction with each trapper operating member is arranged to act on the latter suchwise as to hold the :revelant trapper open for as long as an introduced yarn is required to be fed to the needles.

In order that the invention may be more clearly understood and readily carried into practical effect, a spe: cific constructional example of a striper mechanism arranged for feeding a selected one of a plurality, say four,

Patented June 14, 196 0.

the dial needles 4.'

yarns to the dial needles of such a machine equipped with a stationary cylinder and'dial-will now'bc described 7 with reference to the accompanying drawings, wherein,

Figure 1 is a vertical sectional view, partly inside elevation, illustrating the striper mechanism shown in relation not only to the cylinder and dial of the machine but alsoto the means for controlling the said mechanism,

Figure 2 is a front view, of' the striper unitp'er' se as seen in the direction of the arrow A in Figure 1, I

Figure ,3 is a rear view of the unit as seen inithe direction of therarrow B in Figure 1, v V r V t Figure 4 is a detail front view of-the independent yam trapping and severingrunits as view ed in the directio of'the arrow CrinrFigure l, H 7 r Figure! is a cross sectionalview' taken on the line i Fi gl11'6S 7 and 8 are two comparative diagrammatic 4 a a v and 24, on the one hand, and 25 and 26' on the other hand, which blocks are spaced apart height'wise and secured by screws 28 in the upper portion of the framework, are suitably grooved or slotted longitudinally at 23a, 24a, 25a and 26a suchwise as to provide guideways for a plurality of horizontally movable actuator slides 29. As viewed from'either end in Figures 2 and 3, or in cross-section, however, these actuator slides 29 are arranged vertically in close side-by-side relation. Each actuator slide 29 is longitudinally slotted at 30 to accommodate a short tension spring 31 the leading end 31a of which latter is anchored to the front vertical edge of the slide; The rear ends 31b ,ofthe springs 31 are securedlto, a. split pin 32 which extends transversely through the longitudinal slot 30 and is fixed in the side plates 21-and 22, Projecting outwardly from, the rear vertical edge of each actuator slide 29 is a tail butt 33,

7 these butts beingarranged one above the other, in difside views each showing a yarn ffeeder, .a corresponding yarn'placer, movable scissor and trapper blades, a trapper operating .lever, a common actuator, a corresponds ing actuator check pawl or detent and a check detent associated with the trapper operating lever, the specified parts being shown in the positions they occupy at the termination of the first stage (Figure 7) and of the secnd stage (Figure 8) of advance of the said common actuator ,when selected, and a Figure 9 is a perspective view corresponding to. Figure 8. a

Like parts are designated by similar reference characters throughout the drawings. 7 7 7 Referring to Figure 1, it will be seen that the circular knitting machine to which the striper imechanism now to :be described is applied includes a stationary cylinder lfurnished'with cylinders needles suchas 2. and 'a stationary-dial 3 equipped with dial needles such as 4. Surrounding the cylinder 1 is an annular cam boxs which is mounted upon a rotary carriage 6. Cams. '7 and 8 attached respectively to the cam box and the roferenthorizontal planes and indicated more clearly 'in Eigure ,3; Ih'us, by pressing, inwardly upon the end of arselected tail :butt'33, the corresponding actuator slide 29 is advanced against the action of its controlling ten l. sion spring 31. In the upper horizontal edge of each actuator slide there are formed two, small V- shaped notches 34 and 35 arranged one closely behind theother. A check pawl 36 is provided for engagement successively in these. notches 34 and 35, whenever an actuator slide 29 is advancedagainst its spring action as described. Thatis to say, there is one check pawl 36to each actuator; slide 29v,tthese check pawls being mounted side by sidefor pivotal movement independently about a transverse pivot pin 37 located between the vertical side plates 21 and 22*"of the framework. ,To' expose the notched uppers edges of the actuator slides 29 for cooperation with the check pawls 36, and at the sametime provide 7 theuecessaryspace for accommodation'of the latter, the

' longitudinally grooved o'r slotted upper transverse guide blocks or plates 23 and 24 assisting in'the guidance of said actuator slides are spaced apart longitudinally with ta'ry carriage 6 "are arranged to provide between them a a track T into which extend knitting butts 9 onthe cylinder needles 2 Above the stationary dial 31there is a rotary dial cam-plate 10V to the underside of which are attached carnsxll and '12 arranged to provide between them a track T into which extend. knitting 'butts 13 on Aszdepictedin Figure ll thc, control mechanism of, the machine includes a peripherally notched chain wheel 14 wheel, Extending over the'chainwheel' I4 is a timing or patterning chain 18tfurnishedrwith lugs 19.

a space S between them (seeFigurel). 'Each' slide check pawlr36'is' connected with a tension spring 38 serving to of a selected slide 29 accordingly takes place in twosepwhichis securedupon anlaxle 15, and is adapted to be 'The striperfunit, indicated generally at 20," is mounted upon and arranged tojrevolve together with: the ro-r tat'able cylinder cam box 5 and'the dialcam-platell). In

i regardithe said unit may-be supportedupon 'a bracket orfhrackets' (not shown) carried by & any appropriate partjofthe knitting 'head ofithe machine.

vertical Side plates 21"andr22 (FigureslgaudS) which zontal, planes vand function. also for the purpose hereinv f The unit comprises two suitably spaced, and parallel arate, and distinct stages defined by engagement of the 7 relevant spring-influenced checltgpawl 36 successively. in

the two V-shapednotches' 34 and 35.

, 40. The-outerend 39b of the plunger 39 is of less width after O IeXP iflQ -r The framework ofrthe-sn'iperr V i i i f ifl, 'whi ihi is rectangular in plan,- is. directed radially awards with its lower, portion .20 located adjacent to the cylinder'fand dial needles 2 and 4. Regarded "from eithertside, the 7 upper portion of the framework-is rectangular nshape whil'stits lower portion 20a is of downwardlyitaperingbfonm (see Figure :1);

than'its' operative end 39a and, 'as' shown inFigures 1 and 3; projects from the framework. at ailo'cationsomee what above the uppermost butt33 of the series of butts 33 on the actuator slides 29. .It to be clearlyt understood, however, that'whenever the check pawl release responding to an outgoing-yam. On theotherrhand, a ';freshly:selected.actuator slide129fthez-butt 33 of which,

as shown in Figure 8, is engaged by'thecommon'selector 41 .at' the moment the check pawls 36 are tripped will remain inv its advanced position,

a shoulder 43 for contact with a correspondingtrapper operating lever 44 hereinafter to be described.

Mounted to fulcrum about a transverse pivot pin 45 set in the framework, at a location in front of and a little above the lower horizontal edges of the actuator slides 29, is a plurality of depending and individually operable yarn placers 46 -one to each such slide. When in its normal retracted (non-feeding) position depicted in full lines in Figure 1, each yarn placer 46 extends downwardly and rearwardly somewhat so that a protuberant yam-engaging nose 47 provided at its lower extremity is withdrawn within the framework. A lower marginal portion of each yarn placer 46 adjoining its nose 47 is bent upwardly to form a channel 48-shown more clearly in Figure 9. Rigidly secured to the upper end of each yarn placer 46, at the same side thereof as the channel 48, is a rearwardly directed operating element 49 having an upwardly extending tail 50 for contact by the front lower corner of the corresponding actuator slide 29 (see Figure 1). The normal retracted position of each yarn placer 46 is determined by contact of the rear inclined edge 51 of its operating element 49 with an inclined frontal face 52 of the front longitudinally grooved transverse block or plate 26 assisting to support and guide the actuator slides 29.

Provided at the channelled side of each yarn placer 46 is a comparatively thin companion yarn feeder 53 in the form of a lever with a yarn guiding lower extremity 54. These yam feeders are, at or near their upper ends, mounted to fulcrum about a transverse pivot pin 55 which is set in the framework at a location substantially below and to the rear of the transverse pivot pin 45 constituting the fulcrum of the yarn placers 46. Each yarn feeder 53 extends forwardly and downwardly from its fulcrum and passes through, and in contact with the bottom, of the channel 48 formed at the lower extremity of the companion yarn placer 46. The lower extremity 54 of each yarn feeder 53 projecting from the leading end of the channel 48 extends vertically downwards (when the feeder is in its retracted or non-feeding position indicated in full lines in Figure 1). Each yarn placer 46 and the companion yarn feeder 53 are influenced by a single tension spring 56 connecting the two together. As shown more clearly in Figure 9, one end of this return spring is anchored to a lug 57 provided on the upper end of the yarn feeder 53 adjacent to itsfulcrum 55 whereas the opposite end of the spring is connected to a pin 58 fixed in the underside of the operating element 49 rigid with the yarn placer 46. Now during the first stage of the advance of a selected actuator slide 29, determined by engagement of the corresponding check pawl 36 in the first V-notch 34 in said slide, the lower front corner of the latter pushes against the rear inclined edge 51 of the operating element 49 rigid with the corresponding yarn placer 46 and pushes this forward against the action of the relevant spring 56. As the placer 46 turns about its frulcrum 45 the operative yarn engaging nose 47 thereof swings forward in a practically straight, but slightly arcuate, path above and clear of advanced dial needles 4. At the same time, the companion yarn feeder 53 is acted upon by the bottom of the channelled portion 48 of the yarn placer 46 and is turned upwardly about the yarn feeder fulcrum 55 so that the yarn guiding extremity 54 of the said feeder moves along a near-vertical arcuate path in front and clear of the hooks of the advanced dial needles. Thus, as will be appreciated, this conjoint movement of the nose 47 'of the yarn placer 46 and the yarn guiding extremity 54 of the yarn feeder 53 causes the relevant ingoing yarn Y (see Figure 9) to be gagement of the yarn with the needle hooks. As the.

actuator slide 29 reaches the end of its first stage ofadvance', the upwardly extending tail 5%) on the operating element 49 rigid with the yarn placer'46 engages beneath the lower horizontal edge of the slide as illustrated in Figure '7. Accordingly, continued forward movement of the selected slide29 during the second stage of its advance will take place independently of the yarn placer 46 which, during this stage, will remain stationary. This will be apparent from a comparison of Figure 8 with Figure 7, and the arrangement is such as to provide lost motion between the slide and the placer.

In a case where the machine is equipped with Jacquard patterning mechanism, an ingoing yarn may be introduced to the needles at a gap in the needles resulting from predetermined ones of the latter being unselected.

In the specific example illustrated, the lower ends of the vertical side plates 21 and 22 of the framework of the striper unit are connected by a horizontal transverse plate 56 surmounted by'a vertically slotted block 57 constituting a common carrier for the independent trappingand severing units U. These units U are located immediately beneath the lower yarn-guiding extremities 56 of the yarn feeders 53. Common to all of the trapping and severing units U is a transverse spindle 58 upon which are pivotally mounted pairs of conjointly movable trapper blanks 59 and scissor blades 60. Viewing the trapping and severing units U from the front and side, as in Figures 4 and 5, respectively, it will be seen that each such unit comprises a fixed cutter block 61 at the righthand side of the unit, when an immediately adjacent pivoted scissor blade 60 for co-operation with the fixed cutter block, next a fixed trapper part 62 and, adjacent to the latter and at the left-hand side of the unit, a pivoted trapper blade 59 which is rigid and movable together with the corresponding pivoted scissor blade 60. The unit, the component parts of which are more clearly shown in exploded condition in Figure 6, is completed by the provision of a blade spring 63 which, by exertion of pressure laterally upon the left-hand side of the pivoted trapper blade 59, provides sufiicient friction between the latter and the fixed trapper part 62 to exercise the necessary grip' upon a yarn withdrawn from knitting. Each pivoted scissor blade 60 is extended rearwardly to provide an arm 64 and this blade and also its companion trapper blade 59, are articulated, by means ofa pinand- slot connection 65, 66, with the lower end of a corresponding upwardly and rearwardly extending trapper operating lever 44.

All of the trapper operating levers 44 are mounted to turn about the same transverse pivot pin 55 constituting the fulcrum of the yarn feeders 53. Anchored to the outer end of each pivoted scissor blade actuating arm 64 is one end of a tension spring 70 the opposite end of which latter is anchored to a transverse pin 71 carried by the side plates 21 and 22 of the framework. Turn ing movement of one of the arms 64 against the spring action simultaneously opens both the relevant trapper and the adjoining scissor device. On the other hand, release of such arm permits it to turn in the reverse direction under the reaction of the corresponding spring 79 suchwise as smartly to close the trapper and scissor device. An outgoing yarn trapped in a trapper is crimped byvirtue of extending around the edge of the fixed trapper part 62 and between the outer side of the latter and the inner side of the pivotedtrapper blade 59 as well as between the inner side of the said fixed trapper part 62 and the opposing face of the pivoted scissor blade 60.

The upper end of each pivoted trapper operating lever 44 is, as shown more clearly in Figure 9, formed with an upwardly directed extension 72 extending beyond the fulcrum 55, and this extension projects through aslot 73 formed in the rear one 25, of the two lower grooved blocks or plates supporting and' guiding the actuator slides 29. In fact, the extremity of the said upwardly directed extension 72 of each lever 44 is arranged to be V in the path of the shoulder 43 produced by recessing at 42 the lower horizontal edge'of thecorresponding actuatonslide 29. Consequently, during the second stage in the advance of. a selected actuator slide 29, the relevant shoulder 43 acts on the upwardly directed extension 72 of'the corresponding trapper operating lever 44 and pushes this extension forwards as depicted in Figure 8 with the result that the lower end of the said lever is drawn back toturn the arm 64 articulated thereto and so open the trapper 59, 62 and scissor device 60,61 against spring action. 7 V j a V .For maintaining a trapper 59, 62 and scissor device60, 61 open for as long as may bedesired, there is provided,.in

' association with each trapper operating lever 44, a spring influenced pivoted detent74 (Figures. 1 and 9) which, whenever-the upwardly'directed extension 72 of the lever is pushed forwards as just described, snaps into position behi d. e w rd y e in Proj c n 5. nth

lever. All'of these springtinfiuenced detents74 are pivotally mounted individually upon a transverse'spindle76 set in the framework, and thesaidrdetents are providedgwith depending lugs '77 adapted to be, acted on simultaneously:

by a second'release plunger-78. This plunger 78,.like the hereinbefore described-first release plunger 39, is mounted upon the. transverse block or plate 27 and is provided with an operative inner end 78a sufiiciently wide to act on all the detents 74 together. As shown in Figure 3, the outer end 78b of the second release plunger .78, which latter is controlled by a compression spring 80, is of a somewhat narrower width and projects outwardly from the framework beneath the superimposed butts 33 on'the actuator slides 29. 1 a a For action selectively upon the tail butts 33 of the'actu-J atorslides 29 there is provided 'a profiled portion of, or

part on, the common selector 41' in theform of a striker plate which is adapted to beshif'ted-up or down, under suitable control, either into one or another: of the aforementioned difierent planes or into a neutral position (indicated in Figure: 1) below and clear'of thetail butts 33. When thecommon selector is in the neutral position the mechanism is. inoperative'andi no yarn change c'an take place. Butwhenever, on theother hand, the selector 41 is moved into one of. the aforementioned planes, then relative rotation betweenthe yarn feeding and changing mechanism and the said selectorwill cause the inner end ofthe later to acton the desired tailbutt 33 to advance the-selected actuator slide 29 and thereby initiate-either introduction of a yarn or a yarn changeJ- i The plungers 39 and '78 for tripping first the check pawls 36 and thenthe'independent pivoted'checkflet-ents' 74, andso eifectingfirst' withdrawal from knitting of outgoing yarn: and then trapping and cutting of this yarn, are operated respectively by" striker cams or cam-like members 82 and 83 associated and movable conjointly with the common selector 41. The'timing is'such, how

ever, that the tripping of the plungers 39 and 78, is delayed until the new yarn has been introducedjhy selection of the relevant :actuator slide 29.

1 As'will be seen in Figure-l, the common'selector '41 in the specific'example illustrated is mounted upon'a carrier I 84- which is slidable to various-positions heightwise along a vertical guide post- (not shown), the carrier being guided V by'an additional post 85, and {the selector restingagainst aguide plate 86. The guide posts are secured in a fixed bracket 87 to the underside of which is'attached a sleeve 88, for the guidance of a vertically 'movablerod .89; The

upper end of this rod is articulated to the selectorcarasses-.

93'and isadaptedto be held down against the spring action (with the striker cam 83 below and clear o'fthe' plunger 78,) by means ofthe selector carrier 84 whenever the selector 41 is in its neutral position. But when the selector 41 is shifted up into anyone of the planes'concorned, the'carrier 92'will be released and permitted to" move up' under the influence of the spring 93 to an extent suflicient to dispose the striker cam 83' in the path of the plunger 78. 1 i

, Thus, assuming one .of. the striping yarns is already being fed to the dial needles 4, then, 'to eifect a yarn change by substitution of the feeding yarn by another of the striping yarns, the common selector 41 is first shifted,

upor down, as the case may be, out of the plane in which i t engages the tail butt 33 of the previously selected slide.

29 into another plane in whichit will engage the butto'f 'the newly selected slide. Then,; after thcrnew yarn has been introduced to and safelytaken by. a fewneedles, the.

first releaseplunger 39 is pressed in as a 'consequenceo'f' which the actuator slide corresponding to "the yarn tobe withdrawn is-releasedto effect retraction of the relevant yarn placer 4 6- and companion yarn feeder 53 to their non-feeding positions. This action lays the outgoing yarn across the appropriate trapper and severing 'unit U, whereupon the second release plunger 78 is immediately pressed in to trip; thev appropriatetrapper operating lever 44 and so close the corresponding trapper and scissor device to trap and sever this yarn.

For lifting the yarn feeders 53 manually as occasion may demand there is provided an element 94 which, as

shown in Figure 1, is secured to -a spindle 95 furnished 7 with a knob 96 (see Figures 2 and 3). r I

feeding and changing mechanism comprising a plurality of .yarn feeders Pivotallymounted'sideby side,adjacent to thecylinder and dial; each ofsaid feeders adapted to V moveupwardly fromanon-feeding positionintoafeed feedersand pivotally mounted side by side: for movement ing position; a plurality of corresponding selectively operahle yarn placers arranged in contact with said yarn radially inwards and outwardswith respect to the needles;

an independent yam trappingv and severingunit-foreach yarn feedensaid unit comprising a trapper having tired and pivoted trapper elements and a-cutter having fixed and pivoted scissor" elements, levers which are mounted to pivot independently of, but about the same axis as, the yarn feeders and are pivotally connected to the pivoted trapper and scissor elements for operating the same, common actuator slides mounted side by side each for pushing against and actuating a yarn placer-and hence rier 84 whil'st at its lower end thesaid rodimpinges on i aco'ntrol lever having aitoe'91 arranged; to be acted upon by lugs such a's'19 of different heightson the timing "or patterningchain 18. The striker'camr82extends up;

w'ardly from and is 'rigid with the commontselector 41. The strikericam 83,- on 'the other "hand; is securedv tea 1 m msw e also the yarnfeederin' contact therewith, as well as the correspondingtrapper and-scissor operating. leveneach of saidslides having in one of its longitudinal edges two spaced, formations, an'individual springinfluenced check pawl for engagement successively in said'spac'ed formations of eachslide at required times, springs biassingfthe actuator slides in a radial direction away from the common axis of the cylinderand diaL-an intermittentlymov? able timing chain, and control connections between said timing chain and the common actuator slides-for 'selec 'tively' advancing said slides against the biassing springs,

each of the actuator slideswhen so advanced moving intwo separatestages defined by; successive engagement of 9, r the relevant check pawl in the two spaced formations in the slide.

2. In a circular knitting machine of the cylinder and dial type, a combination according to claim 1 wherein there is lost motion between each yarn placer and the corresponding common actuator slide, during the second stage of advance of the latter, whereby the said placer and the companion yarn feeder remain stationary in their operative positions while the actuator slide is advancing to complete its second stage of advance to effect actuation of the corresponding trapper and scissor operating lever.

3. In a circular knitting machine of the cylinder and dial type, a combination according to claim 1, wherein an individual spring influenced check detent, separate and distinct from the corresponding actuator check pawl is provided in conjunction with each trapper and scissor operating lever to maintain the latter in the position to which it is moved by the corresponding common actuator slide during the second stage of the advance thereof.

4. In a circular knitting machine of the cylinder and dial type, a combination according to claim 3' including spring means for each trapper and scissor operating lever whereby whenever an actuator slide moves during the second stage of an advance, it actuates the relevant trapper and scissor operating lever against the spring action and the corresponding check detent is automatically disposed to hold said lever in a loaded condition, and also including control means for triggering of a check detent associated with a loaded trapper and scissor operating lever whereby when a detent is so triggered, the corresponding trapper and scissor operating lever is released under the spring action to close the trapper.

5. In a circular knitting machine of the cylinder and dial type, in combination, a cylinder; a set of needles in said cylinder; a dial associated with and concentric with respect to said cylinder; a further set of needles in said dial arranged to co-operate with the needles in the cylinder in the production of knitted fabric, and a yarn feeding and changing mechanism comprising a plurality of yarn feeders pivotally mounted side by side adjacent to the cylinder and dial for movement such that its yarn guiding extremity moves up along an upright arcuate path from a non-feeding position into a feeding position clear of the hooks of the dial needles, and vice versa, a plurality of corresponding selectively operable yarn placer-s disposed in contact with said yarn feeders and pivotally mounted side by side for movement radially inwards and outwards along a slightly arcuate path with respect to the needles, each yarn placer when so moved inwardly first raising the companion yarn feeder into its feeding position and then introducing a straight length of yarn extending between said feeder and the corresponding trapper to the dial needles, an independent yarn trapping and severing unit for each yarn feeder, said unit comprising a trapper having fixed and pivoted trapper elements and a cutter having fixed and pivoted scissor elements, levers which are mounted to pivot independently of but about the same axis as the yarn feeders and are pivotally connected to the pivoted trapper and scissor elements for operating the same, common actuator slides mounted side by side and each having formations for pushing against and actuating a yarn placer, and hence also the yarn feeder in contact therewith, as well as the corresponding trapper and scissor operating lever, each of saidvslides having in one of its longitudinal edges two spaced formations, an individual spring influenced check pawl for engagement successively in said spaced formations of each slide at required times, springs biassing the actuator slides in a radial direction away from the common axis of the cylinder and dial, an intermittently movable timing chain, control means between said timing chain and the common actuator slides for advancing said slides against the biassing springs, each of the actuator slides when so adr 10' a a vanced moving in two separate stages defined by success sive engagement of the relevant check pawl in the two spaced formations in the slide, the first stage causing the yarn placer to swing forwards towards theneedles and the companion yarn feeder to swing up from its nonfeeding position, and the second stage causing the corresponding trapper and scissor operating lever to mm and so open the trapper, and means operable under the control of the timing chain for acting on and disengag"-' ing any desired check pawl from the secondmentioned formation in the relevant actuator slide to relessethe latter for return to its inoperative positionunder the action of its biassing spring. a

6. In a circular knitting machine of the cylinder and dial type, a combination according to claim 5 including individiual pivoted spring influenced check detents auto: matically turnable underthe spring action into operative. positions to maintain the trapper andscissor operating levers in the positions to which they are moved by the corresponding common actuator slides during the second stage of the advance (thereof, springs controlling said, operating levers and against the action of which the'lat ter are actuated when pushed by said slides during such advance thereof, and control means for turning a selected check detent against the spring action and thereby releasing the corresponding trapper and scissor operating lever, to close the trapper and cutter.

7. In a circular knitting machine of the cylinder and dial type, a combination according to claim ,5 wherein one end of each trapper and scissor operating lever is articulated by means ofa pin and slot connection to the movable trapper and scissor elements of the correspond ing independent yarn trapping and severing unit.

8. In a circular knitting machine of the cylinder and dial type, a combinationaccording to claim 7 wherein the movable scissor element of each independent-yam trapping and severing unit is extended beyond the'pin and slot connections to provide an arm, and wherein the said movable trapper and scissor elements of said unit are controlled by a spring which is anchored to said arm.

9. In a circular knitting machine of the cylinder and dial type, in combination, a cylinder; a set of needles in said cylinder; a dial; a further set of needles in said dial; and a yarn feeding and changing mechanism ineluding a plurality of side by side yarn feeders for feeding yarns selectively to the needles, a plurality of corresponding side by side selectively operable yarn placers for contacting and moving the companion yarn feeder from a non-feeding position into a feeding position where the yarn is favorably disposed for introduction to needles of one of the two sets in the machine and for acting on the yarn so disposed to displace it in a radially inward direction to effect such introduction, an independent yarn trapping and severing unit for each yarn feeder, said unit comprising a trapper having fixed and movable trapper elements and a cutter having fixed and movable scissor elements, members for operating the individual trappers, common actuators in the form of slides which are arranged side by side and are provided with tail butts disposed in respectively different planes, each of said actuators serving to actuate a yarn placer and the corresponding trapper operating member, a common selector to be moved from a neutral position clear of all the tail butts into a desired one of the aforementioned planes, means for effecting relative rotation between the yarn feeding and changing mechanism and said selector, and control means for moving the selector into a desired plane, whereby whenever the selector is moved into one of said planes the relative rotation will cause the selector to act on the desired tail butt to advance the selected actuator, each of said actuators, when selected and advanced to initiate introduction of a yarn to needles of the aforesaid set being advanced in two separate and defined stages, first causing said placer to contact the 7' cpmpanionyarn feeder :7 10. la a" knittingfniachiue or thefcylinder' and dialitype, a cylinder, a series needlesfin said cylinder;

a; diah a further setfOf needles in said dial; and "a'y'arnf r ading anu'lchans nszmechanism including a plurality of' yami feeders'i forgfeedin selectively to, the needles, a plurality of cjorrefsp'ending selectivelyrf op erable yarfn'jplacersffori eo'ntactin'giand moving the companion yarn feeder front a nOn feeding position into; a feeding position where its yarn is favorably disposed for intro dueti'on' to" the needles of one of the two sets in the machineiandjor acting on the so disposed to dis"- it'tofefie'et such introduction, an independent yarn trapping iand'severinglunitto each yarn feeder, said unit comprising a trapper having'relatively movable trapper 'eremjmtsand jantl a cutter having relatively movable scis- 7 'sorelem'ents; members; for, operating the individual trap- 'pe'rs; ebn1mon actuatorsi for actuatinga yarn placer 'andi a corresponding" trapper operating member, said actuators being inrthe form of Slides which are provided with'tail' *b'utts' disposed in respectively ditferent' planes, at longitiidinal edge of each of said actuators having'therein two spaced formations, individual spring influenced 'check pawls for" engagement successively in said spaced forma- 1 n tion's, biasing, the actuators towards normal in- 7 operative positions, a common selector which is adapted.

to be'moved from a neutralposition clear of all of the tail, butts into a desired one of the aforementioned'planes; nieans'for efiectingrelative rotation between the yarn fecdingand changing mechanism and said selector, con-, trel rueans for moving-the selector into 'a desired plane, whereby whenever theselector-is moved intooneofthese the relative rotation-causes the selector to act on anddisplace itfrom 7, its non- I "n' g: :to' :its position'gand secondly operating the corresponding trapper operating member to open the releva t-trapper and release the yam introduced to the the ,desired tail butt to advance. the selected actuator 7 against the relevant biasing spring, each "of said acmstdrs,

whenselected andadvanced to initiate introduction of a yarn tojneedles of the aforesaid set, being advanced in two "separate stages defined by engagement of therelevant check pawl successively in the spacedfformation'in the 15 pending common actuators during the 's'econdstageof actuator, Jfirst moving the corresponding yarn placer into operative position and causing said placer to contact the companionjyarn and displace it to its feeding position and secondly operating the corresponding trapper mem her to open the trapper 'and release the yarn introduced to the needles, individual spring influenced check detents,

separate and distinct from the common actuator" check pawls,. for maintaining the trapper operating members in 'thepositions 1to whichjthey are moved 'by the c'orrethe advancjepth'ereof, a plunger for disengaging actuator check pawls from theisecond formations in theactua'tors,

- a second plunger for trippingthe' independent check deg 29.

tents associated with the trapper operating members; and

' striker cams which are influencedby the common selector 7 secured to its upper end an operating element adapted for contact by the corresponding actuator.

' i heferences Cited in the file of fliis patent UNITED S ATES PATENTS

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