US2820354A - Circular knitting machines of the superimposed needle cylinder type - Google Patents

Description

Jan. 21, 1958 A P. SAUNDERS 2,820,354

CIRCULAR KNITTING MACHINES OF THE SUPERIMPOSED NEEDLE CYLINDER TYPE Filed July 23, 1956 4 Sheets-Sheet 1 Jan. 21, 1958 Fiied July 25,1956

A. P. SAUNDERS I CIRCULAR KNITTING MACHINES OF THE SUPERIMPOSED NEEDLE CYLINDER TYPE 4 Sheets-Sheet 2 F/G'I 2. i

,awnini" Jan. 21, 1958 A. P. SAUNDERS 2,320,354

CIRCULAR KNITTING MACHINES OF THE SUPERIMPOSED v NEEDLE CYLINDER TYPE Filed July 25, 1956 4 Sheets-Sheet 3 F/G.-2' V Jan. 21, 1958 A P. SAUNDERS 2,820,354

' CIRCULAR KNiTTINC MACHINES OF THE SUPERIIMPOSED A I NEEDLE CYLINDER TYPE Filed July 25, 1956 4-Sheets-$heet 4 United States aren't CIRCULAR KNITTING MACHINES F THE SUPERIMPOSED NEEDLE CYLINDER TYPE Alfred P. Saunders, Leicester, England, assignor to Wildt and Company Limited, Leicester, England, a British company Application July 23, 1956, Serial No. 599,501

Claims priority, application Great Britain July 27, 1955 16 Claims. (Cl. 66-14) This invention relates to circular knitting machines of the superimposed needle cylinder type, that is to say, knitting machines comprising axially opposed and suitably tricked bottom or plain and top or rib needle cylinders arranged one above the other, a circular set of double-ended latch needles for operation in these cylinders, a corresponding set of needle-actuating sliders located in the tricks of each cylinder, and associated bottom and top cam systems furnished with cams for operating the sliders whereby the needles can function in either or both cylinders and be transferred from one cylinder to the other; according to knitting requirements.

The invention, moreover, is applicable to such machines in which all of the needles working in the top cylinder can, at required times, be transferred down to the bottom cylinder and provision is made for selective transference of needles from the bottom cylinder into the top cylinder.

in a circular knitting machine of the type referred to, each needle-actuating slider is, as well known, provided at its operative end with a hooked or equivalent formation, hereinafter for convenience referred to simply as a clutch," for 'interengagement at required times with the appropriate hook of the relevant double-ended latch needle and, adjoining such clutch, with a leading extension designed to retain the engaged needle in position at the back of its trick and also to guard the open needle latch associated with the said hook. Spaced axially a short distance from and behind the clutch of each slider is a shoulder for contact with the opposed head of the engaged needle whenever the latter is being pushed by advancement of the slider; whenever, on the other hand, the slider is retracted, the clutch acts on the engaged needle hook and pulls the needle. To enable a slider located in one cylinder to be disengaged from the relevant needle working in that cylinder, preparatory to transference of said needle to the axially opposed cylinder, two conjoint movements of the slider are necessary, viz. (a) an axial movement thereof to move its shoulder into contact with the head of the needle, thereby freeing the clutch of the slider from the previously engaged needle hook, and (b) an outward deflection of the slider to move it clear of the needle and enable the latter to pass by freely when in the course of being retracted by the opposite slider by which it is received.

The object of the present invention is to provide improvements in a circular knitting machine of the type concerned and of a previously proposed form wherein the tips of the leading extensions of the needle-actuating sliders are chisel-shaped, and the backs of the tail portions of the sliders are relieved to provide fulcrum points about which the sliders can be rocked outwardly, by action of rocker cams "on their tails, when being released ro-rn needles or by action of needles on their leading extensions when being engaged or clutched to those needles. The purposeof'the chisel tips is to present cam-like wedge formations adapted to be entered between the relevant hooks and the spoons of the associated latches of needles suchwise as to open these latches-especially when there are no loops on the needles capable of performing this function. In this regard, the success of a transferring action is, of course, the part dependent upon the latches of these needles which are to be interengaged with receiving sliders being open; otherwise the machine becomes jammed.

A disadvantage of a machine of this previously proposed form as heretofore constructed is that the sliders, and especially their leading extensions, are insufficiently steady during transferring actions as to permit of these actions being satisfactorily carried out. For example, when rela tive longitudinal movement between a needle and a slider to receive that needle is being effected, it can sometimes happen, as a consequence of the slider not being firmly held to the back of the relevant trick, that the chisel tip of the leading extension of the slider becomes disposed at the outer side of the spoon of a latch requiring to be opened instead of being properly presented between the inner side of the said spoon and the extremity of the associated hook of the needle. In this event, the latch fails to be opened so that, with the spoon of the latch in engagement with the needle hook, the latter becomes squeezed, rnis-shapen and damaged. Then, again, when a slider is rocked outwardly to disengage (i. e. de-clutch) it from one end of a needle during a transferring action, there has heretofore been nothing to exercise control over the opposing, i. e., receiving slider whilst it is in the course of engaging and being clutched to the opposite end of the same needle.

The fiorementioned improvements are, therefore, aimed at obviating these difiiculties in a particularly simple and efiicient manner as will be hereinafter described.

According to this invention control elements provided in conjunction with the top and bottom cam systems of the machine are so formed and arranged as to be adapted for action upon the leading extensions of the sliders, during needle transferring actions, suchwise as to hold sliders snugly in their tricks during opening of relevant needle latches by the chisel tips of those sliders which are to receive and engage the needles being transferred, and to control the same sliders during such reception and engagement of the needles thereby.

Additional and similar control elements may be provided at any appropriate points in the knitting system where the hooks and latches of longitudinally advancing needles are required to pass the chisel tips of opposing sliders, e. g. when said needles are being advanced from a non-knitting to a clearing position, so as to ensure that these tips are entered between the hooks and the spoons of the associated latches suchwise as to open the latter.

The provision of the control elements for the primary purpose intended therefore not only ensures certain and positive opening of the latches at those ends of the needles which are to be interengaged with the clutches of the receiving sliders, during transferring actions, but also controls, again in a positive fashion, the outward and inward rocking movements of the receiving sliders nec essary to effect such interengagement with the said ends of the needles simultaneously with disengagement of the sliders in the opposed cylinder from the opposite ends of the needles. It is thereby ensured that the receiving sliders are properly clutched to the needles being transferred without jamming and damage, and in a positive manner ensuring that the needles are, in fact, received I and not left behind upon retraction of the sliders.

The control elements may advantageously be in the form of circumferentially extending cams adapted for action upon the outer edges of the leading extensions of sliders at locations :between the clutches and the chisel tips thereof.

In order that the invention may be more clearly understood and readily carried into practical effect, a specific arrangement of control cams as applied to a rotary needle cylinder machine will now be described with reference to the accompanying drawings, wherein,

Figure 1 is a typical vertical section through the knitting head of a circular knitting machine of the super-- imposed needle cylinder type and shows the manner in which one of the said control cams is mounted, Figures 2(a) and 2(b) are a development of relevant portions of the top and bottom cam systems of the machine, as seen from the inside of the latter, and illustrate a complete arrangement of control cams shown in relation to needles and sliders at different stages during selective transference of a needle from the bottom cylinder to the top cylinder,

Figures 3 and 4 are detail part-sectional views showing a needle and the relevant top and bottom sliders at the two successive stages occurring respectively at III-III and IV-IV of Figure 2(a), and

Figure 5 is a detail plan view of one of the control cams showing the manner in which it acts upon the leading extensions of sliders to hold the latter in their tricks.

Like parts are designated by similar reference characters throughout the drawings.

In Figure 1, the reference numeral 2 indicates the rotary bottom or plain needle cylinder, whereas the axially opposed and similarly rotatable top or rib needle cylinder is indicated at 3. These superimposed cylinders 2 and 3 are formed in the usual way with longitudinally extending tricks 4 and 4' respectively in which doubleended latch needles such as 5 are arranged to work. To each needle 5 in the circular series there is provided, in the corresponding and axially aligned cylinder tricks 4 and 4 a bottom needle-actuating slider 6 and an opposed top needle-actuating slider 7. Surrounding the bottom cylinder 2 is a stationary bottom cam box or shell 8 to which are fitted the cams of a bottom cam system for operating the sliders 6, whilst a stationary top cam box 9 surrounds the top cylinder 3 and carries the cams of a top cam system for actuating the sliders 7.

The operating butts of the bottom and top sliders are indicated at 6a and 7a respectively. Each of the sliders, moreover, is formed in the conventional manner with a clutch, i. e. hooked formation 10, for interengagement with the hook 11 of the relevant double-ended latch needle 5 and, adjoining this clutch, with a leading extension 12 adapted to retain the engaged needle in position at the back of its trick and also to guard an open needle latch 13 associated with the said hook. The customary shoulder spaced behind the clutch of each of the bottom and top sliders is indicated at 14.

The circular knitting machine illustrated is of the form wherein the tips 15 of the leading extensions 12 of the sliders 6 and 7 are, chisel-shaped, and the backs of the tail portions of these sliders are relieved at 16 to provide fulcrum points 17 about which the sliders can be rocked outwardly, by action of rocker cams 18 and 19 on their tails 20, when being released from needles 5, as in Figure 4, or by action of needles on their leading extensions when being engaged or clutched to those needles. As previously explained, the purpose of the chisel tips 15 is to open needle latches 13 by entrance of these tips 15 between the corresponding needle hooks 11 and the spoons 13a of the said latches.

In accordance with the present invention control cams, such as those depicted at C C C and C are provided in conjunction with the cam systems of the machine, these cams being adapted for action upon the leading extensions 12 of the sliders, during needle transferring actions, so as to hold sliders snugly in their tricks 4 or 4' during opening of relevant needle latches 13 by the chisel tips 15 of those sliders which are to receive and engage the needles being transferred, and to control the- 4 same sliders during such reception and engagement of the needles thereby.

All of the control cams: may conveniently be of the same form and each comprise, as illustrated more clearly in Figure 5, a short portion 21 located close to and nearly touching the outer tricked or grooved surface of the relevant needle cylinder 2 or 3, and, immediately in advance of this portion, a somewhat longer adjoining portion 22 recessed at 22a (see Figure 5) suchwise as to provide between the operative face of the cam and the opposed cylinder surface a gap 23 which diminishes in width from its leading end to the point where the two portions 21 and 22 adjoin. The surfaces of the recessed portions 22 of the control cams are preferably at least in part smoothly concave. It will accordingly be appreciated that the recessed portion 22 of each control cam'provides a leadin which, if required to do so, will push an outwardly rocked slider smoothly inwards into and towards the back of its trick preparatory to the outer edge of the leading extension 12 of the slider being acted upon by the short portion 21 of the cam. The action of the short portion of the cam on the slider, at the point mentioned, strokes the slider fully back into its trick and, for an instant, positively holds it there. This is fully illustrated in Figure 5 which shows, by way of example, the action of the cam C on the leading extensions 12 of bottom sliders 6 as the latter are pushed inwards into the tricks 4 in the bottom cylinder 2.

Thus, where such a control cam is provided for ensuring the safe opening of the latches 13 of needles 5 which are to be clutched to receiving sliders during a needle transferring action, the said sliders are advanced, ahead of a transfer station, so that their leading extensions 12 can be acted upon by said control cam as a consequence of relative movement between the latter and the sliders in a circumferential direction. In these circumstances, if any of the receiving sliders happen to be projecting outwardly from their tricks, they will not only be pressed back again but also positively held back for an instant by the portion 21 of the control cam to ensure that their chisel tips 15 will correctly enter between the opposed needle hooks 11 and the spoons 13a of the associated latches 13 and open theselatches as the needles to be transferred are advanced. This will be clear from Figures 2(a) and 3, in which the control cam C ensures opening of the upper latches of selected needles like that shown which are to be transferred from the bottom cylinder 2 into the top cylinder 3 and clutched to corresponding top sliders 7. In this case the said top sliders are advanced by a cam 24, ahead of the transfer station T so that their leading extensions 12 can be acted upon by the cam C as the sliders move past the latter circumferentially.

Where, on the other hand, a control cam, such as that indicated at C is provided to control receiving sliders during interengagement thereof with needles being transferred, the leading end of the recessed portion 22 of the cam where the gap 23 is widest serves to limit the extent of the outward rocking movement of the said sliders (caused by virtue of the needles being advanced by a transfer cam and the appropriate hooks 11. thereof moving past the clutches 10 on the receiving sliders), whereupon the control cam strokes the sliders back again into their tricks and positively holds them there for an instant until the receiving sliders, now correctly clutched to the needles, commence their subsequent retraction. This action will be clear from Figures 2(a) and 4 when it is pointed out that each of the top sliders 7 to be clutched to the upper hook of a selected needle, during selective transference of needles from the bottom cylinder 2 to the top cylinder 3, is advanced by a receive cam 25 and the said needle is advanced by a transfer cam 26 (or 35) as a consequence of which the upper hook 11 of the needle, in moving past the clutch 10 of the receiving top slider 7, causes the latter to rock outwardly,

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the extent of this outward rocking movement being, however, determined by the control cam C Thus, in this case, the recessed portion 22 of the said control cam measures and determines the maximum distance permitted between the outer edge of the leading extension 12 of each receiving top slider and the hack of the corresponding cylinder trick 4' at the instant when this slider is rocked outwardly just described.

in the specific arrangement of control cams illustrated in Figure 2(a), two cams C and C are disposed one above another in vertical alignment in advance of the top and bottom transfer stations T and T of the ma chine, the lower one, C of these cams functioning to hold bottom receiving sliders 6 snugly in their tricks 4 to facilitate the opening of the lower latches 13 of needles 5 during transference of all the needles from the top cylinder 3 to the bottom cylinder 2, and the upper cam C similarly acting to hold top receiving sliders 7 snugly in their tricks during opening of the upper latches of needles during transference of selected needles from the bottom cylinder 2 into the top cylinder .3. It is, however, to be clearly understood that as both top and bottom sliders are initially advanced towards each other in the customary manner at the commencement of a transferring action up or down, both sets of sliders will be acted upon by these two vertically aligned control cams C and C thereby steadying the needles whilst the appropriate latches 13 thereof are opened.

In the illustrated arrangement moreover, the rocker cam 18 provided in the bottom cam system for action upon the feet or tails 2d of the bottom sliders d is for the purpose of rocking these sliders outwards to effect disengagement thereof from needles 5 in the course of transference from the bottom cylinder to the top cylinder. This rocker cam 18 is arranged in vertical alignment with the control cam C associated with the top cam system for controlling the top sliders 7 which are to receive the said needles. Similarly, the control cams C provided in conjunction with the bottom cam system is arranged in line vertically with the rocker cam 19 in the top system.

The control cams may be mounted upon any suitable brackets, slides or the like and provision is preferably made for adjustment of the cams, both radially towards and away from the cylinders and also laterally, 1. e. in either direction circumferentially with respect to the cylinders. If desired, the control cams may also be adjustable up and down, that is to say axially 1n regard to the cylinders, these various adjustments enabling the cams to be accurately set in their correct positions. In the specific example illustrated in Figure 1, the control cam C is attached by means of a screw 27 to the lower end of a vertical carrier piece 28 which is in turn secured at its upper end by a screw 29 to a small block 30. A still further screw 31, screwed into a tapped hole formed in the underside of the top cam box 9, serves to secure the block 30 in position. By virtue of the fact that the screw 27 extends through an enlarged hole 32 formed in the vertical carrier piece 28, that is to say a hole of substantially larger diameter than that of the said screw, the cam C can be adjusted vertically up or down. Similarly, by arranging for the screw 31 to pass through an enlarged hole 33 formed in the block 3%, the carrier piece 28 and hence also the cam C can be adjusted both radially and laterally. The carrier piece 23 and the block 36 accordingly together constitute a bracket. The control cam C is mounted and. adjusted in precisely the same way as the cam 0*. Similar adjustable mountings are provided for the cams C and C although, of course, in this case the carrier pieces instead of extending downwards extend upwards from the top of the bottom cam box 8. As will be understood, the carrier pieces vary in length, depending on the precise positions (heightwise) to be occupied by the control cams.

In the particular arrangement shown in Figure 2(a) the transfer section of the top cam system incorporates a withdrawable transfer cam 34 of the bolt type located immediately in advance of the top rocker cam 19, and, in advance of the said transfer cam, there is provided the aforementioned cam 24 which is also of the bolt type to determine whether or not the operating butts 7a of the top sliders 7 are to be depressed for landing upon the transfer cam 34. The receive cam 25, also included in the top transfer section is located above the top control cam C and is adapted to dispose top sliders 7 at the correct level to receive selected needles 5 transferred up from the bottom cylinder 2.

The corresponding section of the bottom cam system incorporates the two transfer cams 26 and 35 spaced vertically one above the other, the upper transfer cam 26 being adapted for action on bottom slider operating butts 6a of a predetermined length only when transferring alternate needles from the bottom to the top cylinder preparatory to producing 1 x 1 rib fabric, and the lower transfer cam 35 being used for selective transfer by virtue of being adapted for action on butts (not shown) of selected jacks such as 36 (Figure 1) arranged beneath the bottom sliders 6. The upper l x 1 transfer cam 26 is arranged immediately in advance of the bottom rocker cam 18, and is preceded by a bottom receive cam 37 whereby bottom sliders are disposed at the appropriate height to receive needles transferred down from the top cylinder 3. In conjunction with this bottom receive cam 37 there is arranged a withdrawable bolt cam 38 which when in its operative position elevates bottom slider operating butts 6a and lands them onto the said receive cam but which, when withdrawn, permits these buts to pass by the receive cam 37 at a low level. A non-selected bottom slider with its butt 6:: at this low level, and a corresponding needle in a non-knitting position, are shown in the bottom portion of Figure 1. A patterning device (not shown) is provided at P, Figure 2(a), for action on the jacks 36 during selective transfer operations. Selected jacks are acted upon by a jack raising cam 39also of the withdrawable bolt type.

In all other respects the transfer arrangements are conventional.

When not knitting, the improved machine can safely be run without yarn or knitted loops on the needles. Moreover, the needles do not sustain damage when fabric is pressed off.

The invention is particularly advantageous when applied to fine gauge machines wherein the needles have fine latches.

I claim:

1. A circular knitting machine comprising, in combination, a bottom needle cylinder having longitudinally extending tricks therein, a superimposed top needle cylinder having therein similar tricks which are axially aligned with the corresponding tricks in the said bottom needle cylinder, a circular set of double-ended latch needles operating in said cylinders, a corresponding set of needle actuating sliders furnished with operating butts and located in the tricks of each cylinder, each slider having at its operative end a clutch and an adjoining leading extension the tip of which is chisel-shaped, and the back of the tail portion of each slider being relieved to provide a fulcrum point about which the slider can be rocked outwardly, bottom and top cam boxes surrounding the bottom and top needle cylinders respectively, cam systems in said boxes incorporating cams for operating the sliders whereby the needles can be transferred from one cylinder to the other, rocker cams in the cam. boxes for action on the tails of the sliders to rock the latter outwardly when they are being released from needles dur-. ing a needle transferring action, and, in conjunction with the top and bottom cam systems, control elements which are formed and arranged for action upon the leading extensions of the sliders, during needle transferring actions,

7 suchwise as to hold sliders firmly in their tricks and so facilitate opening of relevant needle latches by the chiselshaped tips of those sliders which are to receive into their clutches the needles being transferred, and to control the outward and inward rocking movements of the same sliders during such reception of the needles thereby.

2. A circular knitting machine according to claim 1, wherein the said control elements are in the form of circumfcrentially extending cams adapted for action upon the outer edges of the leading extensions of sliders at locations between the clutches and the chisel-shaped tips thereof.

3. A circular knitting machine according to claim 2, wherein all of the control cams are of the same form and each comprises a short portion located close to the outer tricked surface of the relevant needle cylinder and, immediately in advance of this short portion, a longer adjoining portion recessed suchwise as to provide between the operative face of the cam and the said opposed cylinder surface a gap which diminishes in width from its leading end to the point where the said two portions adjoin.

4. A circular knitting machine according to claim 3, wherein the surface of the recessed portion of each control cam is at least in part smoothly concave and is thereby adapted to provide a lead-in which, if required to do so, will push an outwardly rocked slider inwards into and towards the back of its trick preparatory to the outer edge of the leading extension of the slider being acted upon by the short portion of the cam, the subsequent action of this short portion on the leading slider extension stroking the slider fully back into the trick and, for an instant, positively holding it there.

5. A circular knitting machine according to claim 4, wherein in advance of a control cam for ensuring the safe opening of the latches of needles which are to be clutched to receiving sliders during a needle transferring action, cam means are provided for longitudinally advancing said sliders so that their leading extensions can be acted upon by the said control cam as a consequence of relative movement between the latter and the sliders in a circumferential direction, whereby if any of the receiving sliders happen to be projecting outwardly from their tricks, they will not only be pressed back again but also positively held back for an instant by the control cam to ensure that their chisel tips will correctly enter between the opposed needle hooks and the outer ends of the associated latches and open the latter as the needles to be transferred are advanced.

6. A circular knitting machine according to claim 5, wherein the leading end of the recessed portion of a control cam provided for controlling receiving sliders during interengagement thereof with needles being transferred serves to measure and limit the extent of outward rocking movement of the said sliders, caused by virtue of the needles being advanced by a receive cam and the appropriate hooks of these needles moving past the clutches on the receiving sliders and the said cam functions to stroke the receiving sliders back again into their tricks and positively hold them there until the said sliders, now correctly clutched to the needles, commence their subsequent retraction.

7. A circular knitting machine comprising, in combination, a bottom needle cylinder having longitudinally extending tricks therein, a superimposed top needle cylinder having therein similar tricks which are axially aligned with the corresponding tricks in the said bottom needle cylinder, a circular set of double-ended latch needles operating in said cylinders, a corresponding set of needle actuating sliders furnished with operating butts and located in the tricks of each cylinder, each slider having at its operative end a clutch and an adjoining leading extension the tip of which is chisel-shaped, and the back of the tail portion of each slider being relieved to provide a fulcrum point about which the slider can be rocked outwardly, bottom and top cam boxes surround- 8 ing the bottom and top needle cylinders respectively, cam systems in said boxes incorporating cams for op erating the sliders whereby the needles can be transferred from one cylinder to the other, rocker cams in the cant boxes for action on the tails of the sliders to rock the latter outwardly when they are being released from needles during a needle transferring action, two control cams disposed one above the other in vertical alignment in advance respectively of top and bottom transfer stations, the lower one of said two control cams functioning to act on the leading extensions of bottom receiving sliders to hold the latter snugly in their tricks and thereby facilitate the opening, by the chisel-shaped tips of said extensions of the lower latches of needles during transference thereof from the top cylinder to the bottom cylinder, and the upper one of the said two vertically aligned control cams similarly acting on the leading extensions of top receiving sliders to hold these sliders snugly in their tricks whilst the upper latches of needles are opened by the chisel shaped tips of the said extensions of the top receiving sliders during transference of such needles from the bottom cylinder into the top cylinder, a third control cam provided in conjunction with the top cam system, in vertical alignment with the rocker cam in the bottom cam box which acts on the tails of bottom transferring sliders for the purpose specified, said third control cam actin on the leading extensions of top receiving sliders to control the outward and inward rocking movements of the same during their reception of upwardly transferred needles, and a fourth control cam provided in conjunction with the bottom cam system, in vertical alignment with the rocker cam in the top cam box which acts on the tails of top transferring sliders for the purpose specified, this fourth control cam acting on the leading extensions of bottom receiving sliders to control the outward and inward rocking movements thereiof during their reception of downwardly transferred neeches.

8. A circular knitting machine according to claim 7, wherein all four of the said control cams are of the same form and each comprises, a short portion located close to the outer tricked surface of the relevant needle cylinder and, immediately in advance of this short portion, a longer adjoining portion recessed suchwise as to provide between the operative face of the cam and the said opposed cylinder surface a gap which diminishes in width from its leading end to the point where the said two portions adjoin.

9. A circular knitting machine according to claim 7, wherein the control cams are mounted upon brackets secured to the top and bottom cam boxes of the machine.

10. A circular knitting machine according to claim 9, wherein the control cams are adjustable on the brackets both radially towards and away from, and circumferentially with respect to, the needle cylinders.

11. A circular knitting machine according to claim 10, wherein the control cams are also adjustable up and down on the brackets.

12. A circular knitting machine comprising, in combination, a bottom needle cylinder having longitudinally extending tricks therein, a superimposed top needle cylinder having therein similar tricks which are axially aligned with the corresponding tricks in the said bottom needle cylinder, a circular set of double-ended latch needles operating in said cylinders, a corresponding set of needle actuating sliders furnished with operating butts and located in the tricks of each cylinder, each slider having at its operative end a clutch and an adjoining leading extension the tip of which is chisel-shaped, and the back of the tail portion of each slider being relieved to provide a fulcrum point about which the slider can be rocked outwardly, bottom and top cam boxes surrounding the bottom and top needle cylinders respectively, cam

systems in said boxes incorporating cams for operatingthe sliders whereby the needles can be transferred from one cylinder to the other, rocker cams in the cam boxes for action on the tails of the sliders to rock the latter outwardly when they are being released from needles during a needle transferring action, two control cams disposed one above the other in vertical alignment in advance respectively of top and bottom transfer stations, the lower one of said two control cams functioning to act on the leading extensions of bottom receiving sliders to hold the latter snugly in their tricks and thereby facilitate the opening, by the chisel-shaped tips of said extensions, of the lower latches of needles during transference there of from the top cylinder to the bottom cylinder, and the upper one of the said two vertically aligned control cams similarly acting on the leading extensions of top receiving sliders to hold these sliders snugly in their tricks whilst the upper latches of needles are opened by the chisel-shaped tips of the said extensions of the top receiving sliders during transference of such needles from the bottom cylinder into the top cylinder, a third control cam provided in conjunction with the top cam system, in vertical alignment with the rocker cam in the bottom cam box which acts on the tails of bottom transferring sliders for the purpose specified, said third control cam acting on the leading extensions of top receiving sliders to control the outward and inward rocking movements of the same during their reception of upwardly transferred needles, a fourth control cam provided in conjunction with the bottom cam system, in vertical alignment with the rocker cam in the top cam box which acts on the tails of top transferring sliders for the purpose specified, this fourth control cam acting, on the leading extensions of bottom receiving sliders to control the outward and inward rocking movements thereof during their reception of downwardly transferred needles, withdrawable transfer cam incorporated in the top cam system and located in advance of the top rocker cam, and, in advance of said transfer cam, a further withdrawable cam adapted to determine which top sliders are to be acted upon by said transfer cam.

13. A circular knitting machine according to claim 12, wherein the top transfer section also includes a receive cam located above the relevant control cam and adapted to dispose top sliders at the correct level to receive needles transferred up from the bottom cylinder.

14. A circular knitting machine according to claim 13, wherein the transfer section of the bottom cam system incorporates two transfer cams spaced vertically one above the other, the upper transfer cam being adapted for action on bottom slider operating butts of a predetermined length only when transferring alternate needles from the bottom to the top cylinder preparatory to producing 1 x 1 rib fabric, and the lower transfer cam being used for selective transfer by virtue of being adapted for action on butts of selected jacks arranged beneath the bottom sliders.

15. A circular knitting machine according to claim 14, wherein the upper l X 1 transfer cam is arranged in ad- Vance of the bottom rocker cam, and is preceded by a bottom receive cam whereby bottom sliders are disposed at a height to receive needles transferred down from the top cylinder.

16. A circular knitting machine according to claim 15, wherein there is arranged in conjunction with the bottom receive cam a withdrawable cam which when in its operative position elevates bottom slider operating butts and lands them onto the said receive cam but which, when withdrawn, permits these butts to pass by the receive cam at a low level.

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