US2775107A - Circular rib knitting machine - Google Patents

Description

Dec. 25, 1956 Filed Feb. 13, 1953 A. SHORTLAND CIRCULAR RIB KNITTING MACHINE 3 Sheets-Sheet l IIVVE/VTOR mum-mu 3 Sheets-Sheet 2 Filed Feb. 13, 1953 1956 A. SHORTLAND 75,

CIRCULAR RIB KNITTING MACHINE Filed Feb. 13, 1953 3 Sheets-Sheet 3 a/lzhw /mtzml United States Patent CIRCULAR RIB KNITTING MACHINE Arthur Shortland, Leicester, England, assignor to Mellor Bromley & Co. Limited, Leicester, England, a British company Application February 13, 1953, Serial No. 336,812

Claims priority, application Great Britain February 18, 1952 2 Claims. (Cl. 66-27) This invention relates to circular knitting machines equipped with independent latch needles.

Although, broadly speaking, the invention may be applied to single cylinder plain knitting machines, it is principally the intention to apply it to circular rib knitting machines, that is to say circular knitting machines of the kind including at least two tricked needle beds equipped with sets of independent latch needles and having combined therewith cam systems for the conjoint control and operation of the sets of needles, or of associated needleactuating jacks or sliders. In this connection the invention is applicable to machines of the cylinder and dial type as well as of the double axially opposed, e. g. superimposed, needle cylinder type.

In a circular rib knitting machine, the needles in one bed draw loops or stitches in one direction, whilst the needles in'the other bed draw loops or stitches in the opposite direction, thereby enabling the machine to be used in the production of rib fabric and fabric with various purl stitch effects.

Now, in a circular knitting machine the stitch cam or cams incorporated in the single cam system or in one of the cam systems, as the case may be, is or are usually made adjustable for the purpose of regulation of the length of loops or stitches, for example to produce knitted fabric of a required quality, or/and as may be required according to the count of the yarn to be used. Heretofore, the or each stitch cam in a cylinder cam box has been adjustable vertically, whereas dial stitch cams are conventionally pivoted and adjustable in arcuate paths. Thus, whenever a conventionally adjustable stitch cam was adjusted not only was the knocking-over point changed in position as required, but also the inclined leading, i. e. operative, edge of the cam was simultaneously shifted laterally to one side or the other. Consequently, any adjustment of such a cam varied the precise point in the needle circle at which the latches of the needles eifected thereby were turned over and closed by previously formed loops on the needles.

Accordingly, if the latches of needles in the needle bed, or either needle bed, as the case may he, were turned over and closed too early they tended to collide with the latch guard through an opening in which a yarn is fed to the needles at the feed. If, on theother hand, the said latches were turned over too late, a compensating adjustment of the latch guard became necessary.

Moreover, when knitting on needles in both beds of a circular rib knitting machine, an adjustment of a stitch cam at a feeder frequently upsets the relationship between the respective turn-over points for the latches of the needles in the two needle beds. As is well known to those acquainted with the art concerned this relationship is critical, and if, as sometimes happened, a stitch cam adjustment resulted in the latches of the needles in one bed being closed at the same or practically the same time as the latches of the co-operating needles in the other bed, the previously formed loops on the needles were naturally subjected to undue strain.

The primary object of the present invention is to provide, in the cam system associated with a needle bed in a circular knitting machine of the independent latch needle type, a stitch cam or cams which is or are of improved form and adjustable in such a way as to obviate the foregoing disadvantages.

According to this invention, the or each stitch cam incorporated in the cam system combined with the needle bed, or one of the needle beds of the machine, as the case may be, is adjustable obliquely along a rectilinear path disposed at the same angle as the operative edge of the said cam. By the operative edge is meant the leading edge of a stitch cam which edge, by action on the operating butts of the relevant needles, or their associated jacks or sliders, effects retraction of these needles to the knocking-over point at the feeder, or the appropriate feeder, as the case may be.

By virtue of the invention, the operative edge of the or each stitch cam concerned is maintained in the same oblique line whenever the cam is adjusted in either direction; in other words, an adjustment of the said cam does not, as previously, result in any lateral displacement of the operative edge. For this reason, no degree of adjustment of the improved stitch cam in either direction will vary the precise point in the needle circle at which the needle operating butts (on the relevant needles, jacks or sliders) first come into contact with the operative edge of the cam. It follows that the turn-over point for the latches of these needles will remain the same notwithstanding an adjustment of the cam.

In a convenient embodiment of the invention, the opposite side edges (including the operative edge) of the or each stitch cam are parallel to each other, and the cam is slidably mounted, for adjustment, in an obliquely disposed recess provided between appropriately inclined and circumferentially (i. e. laterally) spaced parallel ends of two cams or cam portions secured to the cylindrical cam box, or the dial cam plate, as the case may be.

Thus, although it is principally the intention to apply the invention to the stitch cam or cams incorporated in the cylinder cam box of a machine of the cylinder and dial type, it is also possible, as will be appreciated, to apply it to the dial stitch cams of such a machine. As far as a circular rib knitting machine of the superimposed needle cylinder type is concerned, stitch cams adjustable in accordance with the invention would preferably be incor-- porated in the bottom or plain needle cylinder. In any event, it is only necessary to apply the invention to the cam system associated with one of the needle beds of a circular rib knitting machine.

A stitch cam which is adjustable in the manner hereinbefore described may conveniently be combined with a guard cam which is adjustable conjointly and simultaneously therewith along the same oblique line.

In accordance with a further feature of the invention, a stitch cam which is adjustable in the manner hereinbefore described, may, if desired, be made double-ended and reversible suchwise as to enable it, depending on its position, to present to operating butts a selected one of two knocking-over points separated, circumferentially, by a distance equivalent to a plurality of needles.

In order that theinvention may be more clearly understood and readily carried into practical effect, a specific example thereof applied to a stitch cam incorporated in a cylinder cam box will now be described with reference to the accompanying drawings, wherein,

Figure 1 is a fragmentary portion of a cylinder cam system as seen from inside the cam box and shows, for purposes of comparison with the invention, a vertically adjustable stitch cam,

Figure 2 is a view similar to Figure 1 illustrating a cylinder stitch cam which is obliquely adjustable in accordance with the invention;

Figure 3 is an elevational view, as seen from the outside of the cylinder cam box, of means for automatically adjusting the stitch cam depicted in Figure 2,

Figure 4 is a plan view of the same,

Figure illustrates a cylinder cam box section incorporating obliquely adjustable stitch cams which are double-ended and reversible for the aforementioned purpose, and

Figure 6 is a similar view but with the said doubleended cams reversed.

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

In Figure 1, the stitch cam 1 is of conventional form and is adjustable vertically as, for example, from the lower full-line position to the upper dotted-line position, and vice versa. Whenever the cam is adjusted in this way not only is the knocking-over point changed, e. g. to vary the length of loops or stitches, but also the inclined leading edge 2 of the cam is shifted laterally. Thus, for instance, when the stitch cam 1 is depressed vertically from the said upper to the lower position, the knocking-over point will move down from a to b, and the leading edge 2 wil be shifted laterally to the left from c to d. As a consequence the latches 3 of the needles 4 turn over and are closed earlier with risk of collision with the latch guard 5 through an opening 5:; in which yarn is fed to the needles. When, on the other hand, the cam 1 is raised vertically from the lower to the upper position shown, not only will the knocking-over point move up from b to a, but the inclined leading edge 2 will shift laterally from d to c with the result that the needle latches 3 will be turned over and closed later; inthese circumstances the latch guard will require to be adjusted to the chain-line position. In Figure 1, the needle waves, that is to say the paths followed by the heads of the needles 4, when the stitch cam 1 is in its full-line and dotted-line positions are indicated at W and W respectively. One of the needles 4 is shown, in side elevation, at the left-hand side of Figure l, and in this figure two further needles are shown edgewise with their operating butts 4a in engagement with cams of the system. Of the two last mentioned needles, the right-hand one is approximately at the location where its latch 3 is turned over and closed. In this regard the lateral spacing of the downwardly inclined, i. e. descending, portions of the two waves W and W serves to emphasise the earlier and later closing of needle latches resulting from a vertical adjustment of the stitch cam 1. The vertical chain lines represent the pitch of the needles.

Referring now to Figure 2, which is laid out similarly to Figure 1 to facilitate comparison, it will be seen that the improved stitch earn 6 incorporated in a section of a cylinder cam box, indicated at CB in each of Figures 3 and 4, has a mainly straight operative edge 7 which is inclined at an angle of 48 or thereabouts with respect to the horizontal upper and lower edges of the cam box. The opposite edge 8 of. the stitch cam 6 is straight from end to end and extends parallel to its operative edge 7. The cam' 6 is slidably mounted in an obliquely disposed recess formed between inclined and circumferentially spaced parallel ends 911 and a of two cams 9 and 10 fixed to the inner wall of the cam box CB. The lower edge of the fixed cam 9 immediately adjacent to the inclined operative edge 7 of the slidable stitch cam 6 is mainly straight and horizontal but is somewhat downwardly curved at 9b where it adjoins the said operative edge suchwise as to provide a stitch drawing surface. It is in the region defined by the rounded corner between the underside of this fixed cam 9 and the operative edge 7 of the slidable stitch cam 6 that the latches 3 of the cylinder needles 4 are turned over and closed as these needles pass through the feeder. The lower edge Mb of the fixed cam 10 on the other side of the stitch cam 6 is straight and horizontal. The parallel sides of the obliquely disposed recess are disposed at the same angle as the operative edge 7 of the stitch cam, as a consequence of which whenever the latter is adjusted up or down the said operative edge will move in the same oblique line so that its relationship with the aforementioned latch turn-over location will remain constant. This will be evident from the fact that in Figure 2 the descending straight portions of the two waves W and W are coincident.

The inclined stitch cam 6, and also a guard cam 11 arranged beneath it, are fixed upon a common slide 12 a portion of which is slidable in a correspondingly inclined slot 13 formed in the wall of the cam box'CB. The slide 12 is biassed upwardly bymeans of a compression spring 14 (see Figure 3). The outer side of the cam slide 12 exposed at the exterior of the cylinder cam box CB is formed with a protuberant step-like lug 15 upon the upper side of which is arranged to act the outer end of one arm 16a of a lever 16. This lever is fulcrumed at 17 on the outside of the cam box and has an upstanding arm 16b arranged to be acted upon by an automati-.

cally operable control member 18 which may, as shown in Figures 3 and 4, be actuated at appropriate times by or from a peg drum or like control unit such as 19 mounted, in the case of a machine of the cylinder and dial type, on the top of the dial cam plate 20. the combined stitch and guard cams 6 and 11 can be automatically adjusted from time to time according to knitting requirements. For the purpose of initially setting the stitch cam 6 to draw loops of a pre-determined normal length, there is provided, in this example, on the outside of the cam box CB, an adjusting screw 21 which has a knurled head 22 and is arranged with its leading end pressing down on thetop of the lug 15 formed on the slide 12.

As previously mentioned, a stitch cam adjustable in accordance with this invention may be made doubleended and reversible to enable it to present a selected one of two circumferentially separated knocking'over points. Two such obliquely adjustable cams, incorporated in one cylinder cam box section, are shown at 23 in each of Figures 5 and 6. Each of these cams which is attached, together with an associated guard cam 24, to a slide 25, is differently contoured at its opposite ends so that by detaching it from its slide, turning it round end for end and then re-attaching it to the said slide, the knockingover point can be changed, according to knitting requirements. This will be clear from a comparison of Figures 5 and 6. In Figure 5, the cams 23 are so arranged that their contoured ends 23a oppose the guard cams 24 and the knocking-over points are at e, whereas in Figure 6 the same cams have been reversed so that their opposite ends 23b now oppose the guard cams and the knockingover points are at 1, that is to say considerably to the left, and accordingly in advance, of the points 2.

Double-ended and reversible stitch cams are accordingly useful when altering the set up of a machine to change from the production of, say, 2 x 2 rib knitted fabric (Figure 5) to l x l rib fabric (Figure 6). Thus, for instance, in a cylinder and dial machine set up to produce 2 x 2 fabric, the knocking-over point on the or each adjustable cylinder stitch cam must be in alignment with the knocking-over point on the corresponding dial stitch cam so that both the dial and the cylinder needles knockover together at the knitting location. For producing 1 x 1 fabric, on the other hand, the knocking-over point on the cylinder stitch cam requires to be so disposed that the cylinder needles knock-over earlier than the co-operating dial needles to a circumferential extent of as many as six or seven needles. This change can readily be effected by the employment of a double-ended and reversible cylinder stitch cam at the or each feeder of the machine.

What I claim then is:

1. In a circular knitting machine, in combination, knit- In this way,

ting instruments provided with operating butts, and a cam system incorporating a stitch cam having an inclined operative edge for action on said butts, the said cam being adjustable obliquely at the same angle as its operative edge, being made double-ended and reversible suchwise as to enable it, depending on its position, to present to the operating butts a selected one of two, circumferentially separated knocking-over points.

2. The knitting machine as defined in and claimed by claim 1 further characterized in that a guard cam is combined with and adjustable conjointly and simultaneously with said stitch cam along the same oblique line.

References Cited in the file of this patent UNITED STATES PATENTS Vermilyea Sept. 9, 1884 Aiken Aug. 25, 1885 Klemm Oct. 15, 1907 Ingalls July 27, 1915 Howie et a1. Aug. 1, 1922 Zieve et al July 5, 1949 Stibbe et al. Jan. 31, 1950

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