US 3919862 A
In a method for separating articles during knitting a portion of the yarn interconnecting a previously knitted article and the next article to be knitted is extended between two superimposed cylinders. Pressing off of the previously knitted article proceeds at the same time as the setting up of a set-up course for the next article which commences with the extended yarn portion. The extended yarn portion is cut by a device having oppositely directed cutting faces after the set-up course has been secured on needles. The previously knitted article comes off freely on completion of the pressing-off operation.
Description (OCR text may contain errors)
[ 1 SEPARATING TUBULAR KNITTED ARTICLES Nov. 18, 1975 FOREIGN PATENTS OR APPLICATIONS 1,938,624 2/1970 Germany 66/145 1,012,111 12/1965 United Kingdom..... 66/145 1,066,981 4/1967 United Kingdom 66/14 ABSTRACT In a method for separating articles during knitting a portion of the yarn interconnecting a previously knitted article and the next article to be knitted is extended between two superimposed cylinders. Pressing off of the previously knitted article proceeds at the same time as the setting up of a set-up course for the next article which commences with the extended yarn portion. The extended yarn portion is cut by a device having oppositely directed cutting faces after the setup course has been secured on needles. The previously knitted article comes off freely on completion of the pressing-off operation.
6C1aims, 9 Drawing Figures  Inventors: Gillies Wood, Evington; Alfred Edward Mitchell, Newbold Verdon, both of England  Assignee: The Bentley Engineering Co. Ltd.,
England  Filed: Feb. 6, 1974  Appl. No.: 439,854
 Foreign Application Priority Data Feb. 9, 1973 United Kingdom 6517/73  US. Cl. 66/14; 66/145 R; 66/172 R  Int. C1. D04B 9/10; D04B 35/00; D04B 9/46  Field of Search 66/172 R, 14, 141, 145 R  References Cited UNITED STATES PATENTS 3,342,043 9/1967 Shannon 66/172 R 3,402,575 9/1968 Peberdy 66/172 R 3,492,837 2/1970 Mountain 66/147 3,803,878 4/1974 Lonati 66/14 U.S.- Patent Nov. 18, 1975 Sheet 1 of5 3 919 862 -15 34 78 II I 24 4 42 1.0 28R i I 3834 64 US. Patent Nov. 18,1975 Sheet20f5 3,919,862
U.S. Patent Nov.18, 1975 Sheet4of5 3,919,862
DIRECT/ON OF KN/TT- V US. Patent Nov. 18, 1975 Sheet 5 of5 3,919,862
SEPARATING TUBULAR KNITTED ARTICLES BACKGROUND OF THE INVENTION The invention relates to methods and apparatus for separating tubular knitted articles for use especially in the manufacture of socks or stockings.
In the British Pat. No. 1,124,922 a method for severing articles during knitting is described. The yarn may be cut (see page lines 17-22) by a bluff-like cutting instrument. It has been found however that it is difficult to cut heavy denier and elastic yarns with such an arrangement.
SUMMARY OF THE INVENTION According to this invention there is provided a method of knitting on a circular knitting machine, preferably but not exclusively a superimposed double cylinder circular knitting machine according to which a previously knitted article is pressed off from needles at one position along the circumference of the knitting machine while a yarn is fed to needles at another position to start a set-up course for the next succeeding article which set-up course begins with the yarn extending between the needles and a loop-holding instrument at a higher level than the needles and connected to the previously knitted article; and according to which the yarn extending between the needles and the loop-holding instrument at the beginning of the set-up course is cut, after the set-up course has been secured to the needles, by a cutting device projected into the path of the yarn extending between the needles and the loop-holding instrument. In the case of a double cylinder machine the loop-holding instrument is formed by one or more needles that have been transferred from the lower to the upper needle cylinder. The set-up course is generally secured when it has been fed to at least two needles in the same cylinder. Preferably with a double cylinder machine the set-up course begins with a loop extending from one cylinder to the other and formed by the transfer of one needle of a group of needles to the other cylinder. Suitably the yarn extending between the cylinders is cut before the pressing off of the last course of the previously knitted article is completed but cutting may also be effected when pressing off has been completed and the pressed article is hanging from a needle in the upper cylinder. Advantageously the cutting device engages the yarn extending between the cylinders from a position straddling the yarn. In this way the yarn can be cut by bringing the cutting surfaces of the cutting device together.
Using the invention heavy denier and elastic yarns can be cut with greater facility.
BRIEF DESCRIPTION OF THE DRAWINGS The invention is more particularly described with reference to the drawings in which:
FIG. 1 is a perspective drawing of a yarn cutting attachment partly in section according to the invention;
FIG. 2 is a perspective drawing of the yarn cutting attachment at FIG. 1 in a different position;
FIG. 3 is a perspective drawing of a control assembly for the attachment of FIG. 1;
FIG. 4 is a perspective drawing of the control assembly of FIG. 6 in a different position;
FIG. 5 is a section through a knitting machine having the attachment of FIG. 1;
FIG. 6 is a developed view of a cam lay-out of the knitting machine of FIG. 5; and
FIGS. 70, b and c are schematic plan views of a bottom cylinder of a double cylinder machine, with needles omitted for ease of understanding, during successive stages of the method of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIGS. 1 to 4, a yarn cutting attachment YC (FIG. 1) comprises a main block support 10 attached to a bracket 12 which is bolted to the upper cam-box of a superimposed double cylinder knitting machine (see FIG. 5). The block 10 may be pivoted about its locking screw 14 for alignment of the attachment with the axis of the needle cylinders of the machine. In operation the block 10 is locked up and fixed by the screw 14 with the front directed inwards with respect to the needle cylinder. A cutter block 16 is slidably located by a tenon in a channel 18 cut in a side face of the block 10, and is held on the block 10 by a sideways extending bolt 20 which passes through a slot 22 in the block 10 and is screwed into the cutter block 16. The block 16 in this way is capable of reciprocable sliding movement with respect to the block 10. A slidable top cutter 24 is slidably located in a channel 26 formed in the bottom face of the cutter block 16 above a lower cutter 28 which is secured to the block 16 on both sides of the channel 26 and acts as a cover plate to the channel 26. The cutter 24 has a projection extending through a slot in a side of the block 16 which engages an operating lever which is fulcrummed on a shoulder screw 32 screwed into an extension of the cutter block 16. The cutter 24 is provided on one side near the front of the attachment YC with a recess 27. The cutter 28 has a straight front edge 29 at an angle with the opposed edge of the recess 27. The lever 30 has a forked end located over the projection 25 and is attached above the screw 32 to an inner cable 64 of a Bowden control cable 34 by a cable clip 36. Screwed onto the upper face of the block 16 is a bracket 38 which mounts the Bowden cable 34 and supports a cable adjusting screw 40 for adjustment of the Bowden cable 34. A tension spring 42 is also provided with one end attached to the bracket 38 and its other end attached to the lower half of the lever 30 below the screw 32. The spring 42 acts to keep the cutter 24 in a retracted position at the side of the block 10 when the cable 64 is inactive. A second bracket 44 is attached to the rear of the cutter block 16. The bracket 44 is connected to be operable by a drum cam on the machine to project the cutter block 16 to a forward position. The extent of forward movement is adjustably controlled by means of a stop screw 48 mounted in the bracket 44 which can abut with the rear face of the fixed block 10. An inner cable 50 of the Bowden cable cover 46 is passed through a hole 52 in the fixed block 10 and has its end 54 secured in the hole in a position towards the front of the block 10. A compression spring 56 is located between the block 10 and the inside face of the bracket 44 to cause the cutter block 16 to take up a rearward position when the cable 50 is not actuated, the rearward movement being halted by the bolt 20 when it meets the rear end of the slot 22 (as in FIG. 1). The springs 42 and 56 operate to retain the cutter 24 and 28 substantially in line with the front of the attachment YC.
A control unit CU (see FIG. 3) is provided to control the Bowden cable 64. The control unit CU comprises a main plate 60 bolted to the frame of the machine (not shown). Attached to the plate 60 is a bracket 62 which supports one end of the Bowden cable cover 34, the other end of the inner cable 64 being attached by a cable clip 66 to the end of a control lever 68. The control lever 68 is located in a slot 70 cut in a rotatable shaft 72, and is held in position by a pin 74 extending through the shaft 72 and lever 68. Adjustably mounted on the end of the lever 68 is a nose 76 facing a cam 78 fixed to a continuously rotatable disc 80. The cam 78 is adapted to be driven by the machine drive in an anticlockwise direction. The lever 68 is held in its idle position by a tension spring 82 one end of which is attached to a rod 84 which is screwed into the shaft 72, and the other end of which is attached to a stud 86 screwed into the plate 60. When the lever 68 is in the previously mentioned idle position, the cam 78 on the rotating disc 80 passes above the nose 76. For activation of the lever 68, a cable 88 is attached at one end to a rod 90 which is screwed into the shaft 72 diametrically opposite the rod 84, and the other end of the cable is attached to a cam follower (not shown) adjacent to the main cam drum on the knitting machine. The cable 88 is supported by a bracket 92 which is fastened to the plate 60.
The knitting machine itself is of the nature described in the British Pat. No. 1,124,922 (see FIG.
To explain the operation of the attachment YC it is assumed that a new sock is to be started. At the point in the needle circle at which the new sock is to be commenced, a bolt cam 101 (See FIG. 6) for a back feed station (generally indicated at 150 in FIG. 7a, b, c) is introduced to engage a small group of sliders having butts of medium height. The position of these sliders is generally indicated in FIGS. 5 and 7a, b, c at 28b. The sliders at 281) are situated in the middle of sliders having knitting butts of short height in the bottom cylinder indicated in FIGS. 5 and 7a at 28a. The knitting butts of the bottom sliders 127 are arranged with the short butts on either side of the medium butt sliders in the heel half of the needle cylinders and with long butts in the instep half. As the group of medium butt sliders 127 pass down the bolt cam 101 the cam is moved right in so that all following short and long butt sliders will be lowered. The path of the needles is schematically indicated'in part by a dotted line in FIG. 6 and starts from the right of that Figure. The bolt cam 101 remains in for one cylinder revolution only and as no yarn is being fed at the back feed to needles controlled by the bolt cam 101, the needles will all be pressed off as the sliders associated with such needles engage this cam 101. FIG. 7a shows the initial pressing off stage, the feeder at the back feed 150 being withdrawn from an active position (dotted lines in FIG. 7a) to an inactive position (in full lines). The fabric on the needles passing the back feed 150 is progressively pressed off, the needles on sliders 281) now being free of any yarn. Continuing from the stage where the group of medium butt sliders have passed down the cam 101 they now proceed below a cam 102 until the transfer butts of these sliders encounter a cam 103. The medium butt sliders are then lifted by the cam 103 so that the knitting butts of the medium butt sliders ride up a cam 104 and raise the needles to clearing height. As there is no yarn on the needles at this stage it is necessary to open the latches by other means. In this example the upper cylinder slid ers indicated at 136 in FIG. 6 are directed to a level where the noses of the upper cylinder sliders shown at 105 (which are specially shaped for the purpose) encounter the needles whose medium butt sliders are moving progressively up the cam 104 and open their latches. All needles controlled by short the long butt sliders that follow the needles controlled by the medium butt sliders follow the same path. The empty needles led by the group 28b whose sliders have medium butts continue at clearing height and pass by the transfer station TS. See FIGS. 6 and 7a, b, 70.
At this stage the third slider of the group 2812 is raised by its transfer butt up a transfer cam T.C. shown in FIG. 6 and thus transfers its needle to the top cylinder. To achieve the selection of the third slider, the No. 4 butt on the selector head 129 associated with the third slider of the group 281) is removed, thus allowing a rocking jack located in the same needle trick to remain in a transfer track, while all other selector heads with the No. 4 butt left on are raised by a selector lever in order to cancel out their associated rocking jacks 128 from the transfer track. The bottom slider from which the needle has been transferred is returned to clearing height by the cam 300 after it has ensured that the open latch of its transferred needle is delivered safely behind a latch guard 301 in its open condition. At this stage, knitting of the final course of the finished sock is taking place at the main feed point A in FIG. 6, 7a, 7b and 70 with all sliders passing down the stitch cam 107. The sliders 127 are then raised through the engagement of their transfer butts with a cam 108 to raise the needles to clearing height as shown at (and at 28a in FIG. 5). The needles are being pressed-off at the cam 101 as the needles following group 28b move progressively past the back feed and fully downwards and the latches of empty needles are being opened as the sliders are raised by the cam 104. Empty needles are thus approaching the main feed point A at clearing height, led by the group of four or so needles controlled by medium butt sliders, the third needle of which is now in the upper cylinder.
As the group of needles 28b containing the single rib needle (indicated at 28R in FIGS. 5 and 7b) pass by the main feed point A the yarn is laid by the feeder (shown at 37 in FIG. 5) from the last needle to knit prior to this group into the open hooks of the needles of the group and also into the hooks of the following empty needles. All the needles 28b in the lower cylinder will pass down the stitch cam 107, while the single rib needle 28R passes up the rib stitch cam 111 in the upper cylinder. The bottom cylinder needles (commencing with the group associated with the medium butt sliders) are allowed to remain low, the upthrow cam 108 being withdrawn, so that the loops are not cleared. The single rib needle 28R, having passed up the stitch cam 111, is maintained at this level, a rib depressor 116 being raised at this time and preventing a lowering of the needle 28R. The extended loop is thus held taut. The resulting situation is illustrated in FIG. 711 wherein the yarn cutter is shown projected by a sequence of operations described in the following:
The rib depressor cam 116 referred to is provided to lower the rib needles (after they have drawn loops at the rib stitch cam during normal knitting) just sufficiently to enable their loops to be taken by the sinkers as they move inwardly towards the knockover position.
It is therefore necessary to raise the rib depressor cam during sock separating otherwise the single rib needle 28R, which is stretching the loop to be severed, would be lowered and thus slacken the loop instead of keepmg 1t taut.
Thus the yarn is drawn taut between the single rib needle in the top cylinder, and the plain needles on either side of it in the bottom cylinder. A loop is formed with legs disposed so that they extend vertically across the gap between the opposing ends of the needle cylinders as shown in FIG. 2 and 5.
The rotation of the needle cylinders continues until this extended loop reaches a position in advance of the rib clearing bolt 112, at which location the yarn cutter YC is located on the knitting machine.
Prior to the extended loop reaching the attachment YC the racking mechanism of the machine (not shown) is caused to operate in order to place a cam on the control drum underneath a cam follower to which the cable 46 is attached which is secured at the other end to the block 16 by the bracket 44. Operation of the cable 46 causes the cutter block 16 to be projected forward until the stop screw 48 meets the rear face of the fixed block 10, so bringing the cutters 24 and 28 to rest just outside the circle of needles in the bottom cylinder. During this same rack of the machine, the verge is raised in order to give clearance between the opposed ends of the needle cylinder so that the cutter 24 can be inserted without interference. As the extended loop continues to move towards the attachment YC, a second rack is taken so that a cam follower on the control drum (not shown) to which the cable 88 is attached, can be operated by a cam on the main drum.
Operation of the cable 88 causes the shaft 72 of the control unit CU to rotate in an anti-clockwise direction against the pull of the spring 82, thus raising the nose 76 on the lever 68 into the path of the cam 78 on the rotating disc 80. As the cam 78 passes by the nose 76, the lever 68 is pivoted on the pin 74, causing the inner cable 64 to operate the lever on the attachment YC, this projecting the cutter 24 to a forward position in order to receive the extended loop of yarn to be cut in the recess 27 (see FIGS. 2 and 4).
While the nose 76 remains on the rotating cam 78, the cutter 24 will lie in the path of the loop of yarn to be cut, so that further rotation of theneedle cylinders will bring the legs of the extended loop into the recess 27 of the cutter 24.
At this time the nose 76, on the lever 68, drops off the end of the rotating cam 78 allowing the inner cable 64 to relax, the tension spring 42 then returning the cutter 24 to its rear position in the cutter block ,16, carrying the yarn in the recess 27 past the cutting edge 29 of the bottom cutter 28 where it is cut through, thus separating the two articles which up till now have been joined together by the extended loop of yarn.
On continued operation of the machine the main drum is again racked around. This removes the cams from under the cam followers to which the cable 50 and 88 are attached. Consequently the spring 82 is allowed to rotate the shaft 72 in a clockwise direction, taking the nose 76 out of the path of the rotating cam 78, and at the same time the cutter block 16 is moved to its rear position by the action of the compression spring 56. At this time the verge is lowered to its original position. This operation is illustrated in FIG. 70
wherein the last loops held on the needle of the previously knitted article areabout to be pressed off.
The attachment YC remains idle until the cycle starts again at the finish of the next article. The extended loop, carried by the rib needle thus enters the cutter and is severed by it before the last stitch of the previous article has been shed. At this stage the remaining few needles carrying stitches of the previous article, which preceed the group, are shedding their stitches as their sliders pass down the cam 101 and the yarn extends from the last of these needles into the hooks of the needles of the group 2811 which includes the rib needle 28R. The sinkers are retracted radially inward between the needles at the location of the cutter, and therefore both yarn ends formed by the cutter are laid in a zig-zag pattern around the needles by the sinkers. No loops are as yet being formed. The cutter is by then withdrawn clear of the needle circle. Further rotation to complete a single rotation of the cylinder of the machine causes the previous article to be fully shed from the needles. The bolt cam 101 is then withdrawn. The next article is thus commenced with a set-up course after the yarn has been laid in a zig-zag pattern beginning with one of the ends of the cut loop. Thereafter the needles are divided at the cam 103 so that alternate needles are raised from a float or non-knit position to be transferred to l X l on arrival at the transfer section. The single rib needle in the group of medium butts, on arrival at the transfer section is transferred down to the bottom cylinder to be re-selected, because its location in the cylinder is in ad vance of the needles where the l X 1 selection is to start. After the transfer of the alternate needles they arrive at the main feed station A in a l X l set-out, Le.
alternate needles in the top cylinder and intermediate needles in the bottom cylinder, with the yarn following a zig-zag path from the hooks of the intermediate needles to the hooks of the alternate needles. The knitting process at the station A, then causes the yarns laid in a zig-zag path to be formed into loops forming the first course. Thus socks can be knitted continuously, while the socks are delivered by the knitting machine individually separated.
The construction may be modified from that described. For example, instead of the cam 80, a cam surface may be provided on a part rotating jointly with the cylinders to operate the cutting attachment during the cutting operation. The cutting attachment itself can be modified by mounting the cutters each on a separately slidable block. The blocks could be urged together by a spring and an abutment could be provided to arrest the rearmost block in its projected position. A cable pulling or pushing the foremost member would then successively cause both cutters to be projected and then separate the cutting edges. Release of the cable would then enable the extended loop to be cut and the cutters to be immediately retracted. An alternative and often advantageous arrangement is for the projection of the cutters to be under the influence of the spring and the cutting action and retraction of the cutters to be in response to the direct action of the cable. The cutters are also conveniently mounted underneath instead of to the side of the mounting block.
The invention enables heavy and elastic yarn to be cut. In further modified constructions, the cutter may have a stationary blade positioned permanently to one side of the path of an extended loop. It need then not be elongate. A further movable cutter can then be projected to cut the yarn from a straddling position. The stationary blade must not be at a position at which it fouls the needle latches or verge pieces, but in some knitting machines it is nevertheless possible to position such a stationary blade at a position very close to the needle circle. In a dial and cylinder machine, one or more points on the dial may be used to form the extended loop.
1. A method of knitting on a circular knitting machine having a loop-holding instrument operable to a higher level than needles of the machine, comprising the steps consisting of:
A. pressing off a previously knitted article from needles at a first position on the circumference of the knitting machine;
B. simultaneously feeding a yarn to needles at a second position on the circumference to start a set-up course for the next succeeding article, said set-up course commencing with a yarn portion extending from the needles to the loop-holding instrument;
C. projecting a cutting device into the path of the yarn portion; and
D. cutting the yarn portion by means of the cutting device, the cutting device being positioned between the first and second positions to engage the yarn portion when the set-up course has been secured to the needles.
2. A method as claimed in claim I wherein the knitting machine is a superimposed double cylinder knitting machined having means for transferring at least one needle from a lower needle cylinder to an upper needle cylinder to function as the loop-holding instrument, and prior to cutting the yarn portion extends between the at least one needle in the upper cylinder and a group of needles in the lower cylinder to secure the yarn portion.
3. A method as claimed in claim 1 wherein the cutting device is positioned to engage the yarn portion before pressing off of the last course of the previously knitted article is completed.
4. A method of knitting a succession of articles on a circular knitting machine having a first knitting station, a second knitting station spaced from the first and a device for cutting yarn including: a support mounted on the knitting machine between the first and second knitting stations; a first elongate cutter mounted on the support and formed with a cutting surface adjacent one end thereof; a second cutter mounted on the support and formed with a cutting surface facing in the opposite direction to the cutting edge of the first cutter; a means for projecting the first cutter and for separating its cutting surface from that of the second cutter in a position above the needle circle of the knitting machine; and a means for bringing the cutting surfaces into cooperation;
said method including the steps of: j
A. knitting a main portion of an article B. when the main portion is completed, pressing off the article from needles at the first knittingstation; C. simultaneously feeding a yarn at the second knitting station for starting a set-up course for a main portion of an article to be knit subsequently, the set-up course commencing with ayarn portion extending between a group of needles and a loop-holding instrument at a higher level than the group of needles;
D. actuating the means for projecting the first cutter to place the first cutter in the path of the extended yarn portion; and
E. actuating means for bringing the cutting surfaces into cooperation when the extended yarn portion is received between the oppositely directed cutting surfaces to cut said yarn portion when the set-up course has been secured by the group of needles.
5. A method as claimed in claim 4 wherein the knitting machine is a superimposed double cylinder knitting machined having means for transferring at least one needle from a lower needle cylinder to an upper needle cylinder to function as the loop-holding instrument.
6. A method of knitting a succession of articles on a superimposed double cylinder machine having a first knitting station, a second knitting station spaced from the first and a device for cutting yarn including: a support mounted on the knitting machine between the first and second knitting stations; a first elongate cutter mounted on the support and formed with a cutting surface adjacent one end thereof; a second elongate cutter mounted on the support and formed with a cutting surface facing in the opposite direction to the cutting edge of the first cutter; a means for projecting the first and second cutters together and for separating the cutting surfaces in a position between the cylinders of the knitting machine; and a means for moving the first and second cutter relatively to bring the cutting surfaces in cooperation;
said method including the steps of:
A. knitting a main portion of an article I B. when the main portion is completed, pressing off the article from needles at the first knitting station;
C. simultaneously feeding a yarn at the second knitting station for starting a set-up course for a main portion of an article to be knit subsequently, the set-up course commencing with a yarn portion extending between at least one needle in one cylinder and a group of needles in the other cylinder;
D. actuating the means for projecting the first and second cutters together and separating the cutting surfaces before a full course has been pressed off to place the cutters into the path of the extended yarn portion; and
E. actuating the means for moving the first and second cutters relatively when the extended yarn portion is received between the oppositely directed cutting surfaces to cut said yarn portion when the set-up course has been secured by the group of needles.