US 2876720 A
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Description (OCR text may contain errors)
March 10, 1959 M. A. SOKOLOFF 2,376,729
RUG MAKING ATTACHMENT FOR SEWING MACHINES Filed 001;. 7, 1954 5 Sheets-Shet .1
INVENTOR. maur ga. A. SOKO IO 2:. ATTORNEYS March 10, 1959- M. A. SOKOLOFF 2,876,720
RUG MAKING ATTACHMENT FOR SEWING MACHINES Lled Oct. T, 1954 i 5 Sheets-Sheet 2 IE- I I lllll lllxll hl FIG.
INVENTOR. Maune. tsokolo-Pf Y @njuwm 314M 4;. ATTORNEYS March 10; 1959 v M. A. SOKOLOFF' 7 2,876,720
Rue MAKING ATTACHMENT FOR SEWING MACHINES Filed Oct. 7, '1954 5 Sheets-Sheet 3 FIG.3E
IN V EN TOR. nawv'a eg. A. k H
BY ama M: W
eb- ATTORNEYS March 10, 1959 M. A. SOKOLOFF 2,876,720
RUG MAKiNG ATTACHMENT FOR SEWING MACHINES 5 Sheets-Sheet 4 Filed 001;. 7, 1954 Halo ' INVENTOR. Maurice A- okolo'f- LL. ATTORNEYS March 10, 1959 M. A. SOKOLO'FF 2,876,720
RUG' MAKING ATTACHMENT FOR SEWING MACHINES Filed Oct. 7. 1954 5' Sheets-Sheet 5 Fl 6J3 INVENTOR. Mau n'ae A. fiok ff ATTO R N EYS nited States Patent RUG MAKING ATTACHMENT FOR SEWING MACHINES Maurice A. Sokolotf, Peekskill, J. Y.
Application October 7, 1954, Serial No. 460,905 13 Claims. (Cl. 1129) The present invention relates to attachments for sewing machines, and more particularly to attachments which produce a pile fabric by stitching looped or cut yarn to a backing cloth. The pile fabric thus produced is suitable for use in the production of rugs, and for other purposes where a relatively thick pile fabric is desired.
It has heretofore been customary in the manufacture of rugs of this type to first produce a braid of looped yarn and to stitch the braid in-closely spaced rows to a backing cloth.
Where cut ends of the yarn were to form the upper surface of the pile fabric, the looped ends were sheared in a separate operationto produce an even surface.
The present invention avoidsthe preliminary-step of producing a braid, by forming loops which are positioned to be stitched directlyto the backing cloth by the stitch forming mechanism of a conventional sewing machine.
Where a smooth pile fabric is desired, in which the upper surface is to consist of cut ends of the yarn, the device of the present invention cuts the loops just prior to the stitching operation and adjusts the cut ends relative to the line of stitching to obtain a smooth .even surface in the finished product. The separate shearing operation is thus avoided.
An object of the invention is to provide a yarn looping attachment which may be mounted on the overhanging arm of a conventional sewing machine and which will form loops of yarn extending transversely of the line of stitching, the yarn loops being fed beneath the presser foot along with the backing cloth so that the loops are stitched directly to the backing cloth.
The attachment which is the subject matter of the invention is illustratively shown as being used with a sewing machine for stitching loops to a backing cloth. Obviously, this identical structure may be used with any type of fastening device, including suitable work-feeding means, and the loops may be attached to any type of backing sheet, loop-forming action being appropriately fixed in its speed relationship to the operation of the work-feeding and fastening means.
A further object of the invention is the provision of means for turning the series of loops or cut lengths of yarn held by a previously formed row of stitching away from the backing cloth in order to provide a clear space to permit the formation of an adjacent row of loops or cut lengths of yarn in close proximity to the previously formed row. This allows the production of a fabric having a dense pile consisting of closely spaced loops or lengths of yarn.
Another object of the invention is the provision of means for releasing the loops as they are fed beneath the presser foot.
Still another object of the invention is the provision of loop forming means driven along with the stitch forming instrumentalities of the sewing machine, whereby the loops are formed at a predetermined rate with respect to the stitches. This assures that each transverse element of every loop which extendsacross the line of stitching will be properlypositioned at the time when it is stitched to the backing cloth.
Another object of the invention is to provide a looping attachment of this character which includes cutting means for severing the loops and positioning the free ends of the cut loops with respect to the row of stitching so that the final product, after turning up the free ends of the cut loops, will provide a smooth anduniform.
surface for the finished pile fabric.
Other and further objects will become apparent upon reading the following specification together with the accompanying drawing forming a part hereof.
Referring to the drawing:
Figure 1 is a perspective view illustrating an embodiment of the invention attached to the overhanging arm. of a conventional sewing machine.
Figure 2 is a front view in elevation, showing certain portions of the loop forming mechanism with the enclosure therefor removed.
Figure 3 is an end view of the attachment shown in Fig. 2 with the enclosure in position.
Figure 4- is a perspective view illustrating the loop erecting feature.
Figure 5 is an enlarged exploded perspective view showing the loop feeding and releasing mechanism.
Figure 6 is an enlarged transverse sectional view taken on a vertical plane passing through the line 6-6 of Fig. 5, with the mechanism assembled and looking in the direction of the arrows.
Figure 7 is a plan viewof a square of pile fabric, which is composed of triangular and trapezoidal elements cut from a relatively narrow elongated strip of material.
Figure 8 is a plan view of an elongated strip of material illustrating the layout of the elements which constitute the square shown in Fig. 7.
Figure 9 is an enlarged fragmentary sectional 'view taken along the line 9-9 of Fig. 8 illustrating the closely spaced rows of stitched loops which form a dense pile fabric.
Figure 10 is a view similar to Fig. 9 with the loops.
cut to form a smooth surfaced pile fabric.
Figure 11 is an enlarged fragmentary view in elevation of a modified form of the invention including means for cutting the loops to produce the fabric shown in Fig. 10.
Figure 12 is a sectional view in elevation taken along the line 12-12 of Fig. 11.
Figure 13 is a plan view of the cutting type of attachment shown in Figs. 11 and 12.
Figure 14 is a diagrammatic plan view showing the loop of yarn at the instant when it is cut.
Figure 15 is a diagrammatic plan view showing the cut lengths of yarn correctly positioned and stitched to the backing cloth.
Figure 16 is a diagrammatic view illustrating the lateral position of the pressure foot with respect to the cut and the aligned lengths of yarn shown in Figs. 14 and 15.
Referring to Fig. 1, a part of a conventional sewing machine is illustrated, arranged to form a row of stitching 19. A work table 20 of the sewing machine is operatively associated with an overhanging arm 21. Fastening means such as the usual work feeding and loop forming instrumentalities of the machine are disposed beneath the Work table 20 in conventional manner and do not appear in the drawing. The sewing machine also comprises the conventional vertical presser foot bar 22 and a vertically reciprocating needle bar 23 which operates in the usual mannerto form a row of stitching in a suitable backing sheet such as a backing cloth 25.
The attachment which is the subject matter of the present invention comprises a body 26which is fixedly secured to the overhanging arm 21 by means of a. rigid supporting rod 24. The body 26 is conveniently formed in two sections held together by screws 27. The needle bar 23 passes freely through the front portion of the body 26 and a the presser foot bar 22 similarly passes freely through the rear portion of the body 26.
A loop forming arm 28 is pivoted to the outer end of the overhanging arm 21 at 29 and comprises a laterally extending cam follower portion 30. An operating shaft 31 is connected by conventional means (not shown) to be driven simultaneously with the stitch forming mechanism of the sewing machine. The outer end portion of operating shaft 31 is journaled in a supporting block 32 fixed to the overhanging arm 21 of the sewing machine.
An eccentric cam 33 is fixed to the free: end of operating shaft 31 and engages the spaced upper and lower horizontally extending projections 34 and 35 of the cam follower portion 30 of the loop forming arm 28 so that the loop forming arm 28 is constrained to oscillate about its pivot 29 as cam 33 revolves.
At its lower end, loop forming arm 28 carries a laterally reciprocating yarn guide 36 which is horizontally apertured to permit the passage of a thread-like member such as a yarn 37 .therethrough. The yarn 37 is fed from a supply 38 over a pulley 39 and through fixed guide members40 and 41 to the reciprocating yarn guide 36.
Operating shaft 31 carries a sprocket wheel 42 which drives a larger sprocket wheel 43 through an endless chain 44. Sprocket wheel 43 is fixed to a shaft 45 suitably journaled in the body 26 of the attachment. Mounted on shaft 45 for rotation therewith are two gears 46 and 47 which are symmetrically arranged with respect to the row of stitching 19 formed by the sewing machine, being disposed on opposite sides of the sewing machine needle 48 and pressure foot 49.
A pair of shaft supporting members 50 and 51 extend downwardly from attachment body 26. A pair of cam supporting members 52 and 53 also extend downwardly from body 26 and have sockets 54 and 55 (Fig. formed therein to receive the hub portions 56 and 57 of a pair of angularly adjustable drum-shaped cam members designated generally as 58 and 59, respectively.
The hubs 56 and 57 of the cam members 58 and 59 are fixedly held in the sockets 54 and 55 of the cam supporting members 52 and 53 by means of a plurality of set screws 60. The fixed cam members 58 and 59 may be rotated in their sockets 54 and 55 for purposes of angular adjustment by loosening the set screws 60. The outer end portions of a pair of shafts 62 and 63 are journaled in the shaft supporting members 50 and 51. The shaft 62 has its inner end portion journaled in the hub 56 of cam member 58. A rotary supporting member or loop holder 64 is fixed to the inner end of shaft 62 adjacent to the sewing machine needle 48. The shaft 63 is arranged like the shaft 62, symmetrically with respect to the sewing -machine needle 48. The shaft 63 has its outer end porstruction being symmetrically arranged with respect tothe sewing machine needle 48. Each loop holder comprises a drum-shaped body 70 (Fig. 6) which fits freely around the outside of one of the drum-shaped cam members 58 or 59. The loop holder body 70 is provided with a plurality of rectangularly shaped through apertures 71. A block 72 is pivotally mounted in each aperture 71 on a pivot pin 73, the outward movement of each block 72 being limited by a stop pin 74 which engages a tongue portion 75 of block 72. A loop supporting pin 76 is carried by each of the blocks '72. Each of the loop sup- 4 porting pins 76 is curved slightly away from sewing machine needle 48 and is further curved slightly in the direction of rotation of the loop holder 64 or 65 of which it forms a part.
Each of the drum-shaped cam members 58 and 59 comprises a hollow open ended cylindrical body 78 which is cut away at 79. Whenever one of the blocks 72 is positioned at the cutaway portion 79 of its associated cam body 78, it is free to pivot inwardly so that the loop supporting pin 76 which it carries may move inwardly into the drum-shaped body 70 of the loop holder and be withdrawn from supporting engagement with a loop. When any of the blocks 72 is positioned adjacent to the solid portion of the cam body 78, its inward pivotal movement is prevented and the loop supporting pin 76 which it carries will be constrained to remain in an erect position, projecting generally radially outwardly from the loop holder as the loop holder revolves.
A work supporting platform 80 is disposed beneath the presser foot 49 and the usual work feeding elements of the sewing machine extend upwardly therethrough for engagement with the backing sheet such as a backing cloth 25.
In operation, the sewing machine forms a row of stitching 19 in the backing cloth 25 with the work feeding in the direction of the arrow shown in Fig. 1. Sewing thread 81 is fed to the needle 48 in the usual manner, passing through thread guides 82 mounted on overhanging arm 21. The yarn 37 is moved transversely across the direction of the row of stitching 19 being formed by the sewing machine, passing through the laterally reciprocating yarn guide 36 at the lower end of loop forming arm 28. The path of travel of yarn guide 37 extends beyond the rotating loop holders 64 and 65 sntficiently far to permit the yarn 37 to pass around the loop supporting pins 76 which are carried thereby.
There have been shown by way of illustration four equally spaced loop supporting pins 76 on each of the rotating loop holders 64 and 65. The loop holders 64 and 65 are so positioned on their respective shafts 62 and 63 that the loop supporting pins 76 are staggered, the pins on loop holder 64 being angularly displaced in position by 45 from the pins on loop holder 65. The yarn fed through the reciprocating yarn guide 36 is positioned in the path of travel of one of the loop supporting pins 76 which engages the yarn and draws it downwardly toward the presser foot 49. ,As the yarn is engaged by the loop supporting pin 76, the yarn guide 36 reverses its direction of movement carrying the yarn laterally to be engaged by another supporting pin 76 carried by the opposite rotating loop holder. The yarn is thus zig-zagged back and forth between the staggered loop supporting pins 76 carried by the rotating loop holders 64 and 65. The loop supporting pins 76 introduce the zig-zagged yarn thus carried by rotating loop holders 64 and 65 beneath the upturned toe 83 of the presser foot 49 where it is squeezed against the backing cloth 25 supported on the platform 80 and fed along with the backing cloth 25 into the stitching path of the sewing machine needle 48. The needle 48 thereupon stitches the zig-zagged yarn 37 to the backing cloth 25 in the form of a series of loops 84 extending outwardly from both sides of the row of stitching 19 formed by the sewing machine. The speed of rotation of the supporting members or loop holders 64 and 65 is operationally correlated with the speed of operation of the needle 48 and its associated work-feeding mechanism so that the zig-zagged yarn 37 is stitched at least once to the backing cloth 25 each time that it crosses the row of stitching 19.
The zig-zagged yarn is substantially horizontal as it is fed beneath the presser foot 49 and stitched to the backing cloth 25 by the needle 48, the height of the supporting platform 80 being sufficiently greater than the length of the loop supporting pins 76 to provide clearance for these pins with respect to the work table 20 in their lowermost positions of travel.
After the yarn 37 has been stitched to the backing cloth 25, the block 72 which carries the supporting pin 76 holding the particular loop 84 of yarn which has just been stitched will at that time be adjacent to the cut away portion 79 in the body 78 of its associated cam member 58 or 59. This allows each individual block 72 to pivot inwardly about its pivot 73 and permits its supporting pin 76 to assume a vertical position as it moves upwardly. As the loop holders 64 and 65 continue their rotation past the stitch forming mechanism of the sewing machine, the supporting pins 76 are successively drawn upwardly out of the closed ends of the individual loops, the pins assuming a more or less vertical position which facilitates their successive disengagement from each loop as the loops and the backing cloth travel onwardly past the presser foot 49 in the generally horizontal direction indicated by the arrow.
In order to permit a further series of loops to be stitched to the backing cloth in close proximity to a previously stitched series of loops, a loop turning member designated generally as 86 is provided. The loop turning member 86 is fixed to the attachment body 26 and comprises a rounded nose portion 87 whose lower edge is sufficiently close to the backing cloth 25 to engage the end of each loop of a previously formed series. As the backing cloth 25 is fed along by the sewing machine, the loops of the previously stitched series are progressively engaged by an outwardly sloping shoulder portion 88 of the loop turning member 86 and then by a curved turning portion 89 which turns each loop outwardly and away from the portion of the backing cloth 25 where the adjacent row of stitching is to be formed. This provides a clear space on the backing cloth 25 to which the newly formed adjacent series of loops may be stitched without interfering with the previously stitched series of loops, the end portions of the newly formed series of loops overlying the loops of the previously stitched series. After the material passes beyond the sewing machine, the resiliency of the yarn causes the loops to assume an upright position as may best be seen in Fig. 9, thereby forming a dense pile fabric.
In certain instances, it may be desired to form a pilefabric in which the yarn is cut to provide free ends instead of the closed ends of loops as previously described. This may be accomplished by cutting the ends of the loops as they are stitched to the backing cloth to produce a pile fabric of the type shown in Fig. 10. This may be readily accomplished by the appropriate positioning of cutting knives in proximity to the loop holders 64 and 65.
Referring to Figs. 11, 12 and 13, a pair of loop cutting knives 91 and 92 are held by screws 93 and 94 in a knife supporting block 95. Knife supporting block 95 is secured to attachment body 26 by screws 96.
Rotary loop holders 97 and 98 have annular peripheral grooves 99 and 100 formed therein to receive the free end portions of the knives 91 and 92. The knives 91 and 92 are each provided with a sharpened cutting edge 101 which is directed substantially radially with respect to the common axis of rotation of the loop holders 97' and 93 and lies in a plane normal thereto. There is a slight angle of deviation of each cutting edge 101 from the radial direction, such that the yarn 37 is forced slightly outwardly away from the loop holder at the instant when it engages the cutting edge 101 and is being cut.
Each of the rotary loop holders 97 and 98 is shown provided with four pairs of loop supporting pins 102 103, the outer pins 103 of loop holder 97 being disposed at the outer side of groove 99 and the inner pins 102. being disposed at the inner side of groove 99. The outer pins 103 and inner pins 102 are similarly arranged with respect to the groove 100 of rotary loop holder 98,. the pairs of pins 102103 on loop holder 97 being stag- 6 gered, or displaced by 45 with respect to the pairs of pins 102-103 carried by loop holder 98.
The pairs of pins 102-103 are fixedly securedto the peripheries of loop holders 97 and 98, the loop releasing mechanism described above being omitted because the loops are cut by knives 91 and 92 and released in this manner. The loop holders 97 and 98 are fixed to the inner ends of shafts 62-and 63, respectively, the loops being formed and the shafts 62 and 63 being driven by mechanism which has been described above.
The presser foot 104 is of a modified form of con struction, being provided on its under side with laterally spaced runners 105 and 106. The runners 105 and 106 have relatively sharp edges which engage the yarn as it passes under the presser foot.
Figs. 14 to 16'illustrate the operation of the cutting knives 91 and 92 and the presser foot runners 105 and 106.
In Fig. 14 the yarn has just been cut by knife 91 at between pins 102 and 103. The cut takes place in the leading portion of the yarn looped around pins 102- 103 which is the first portion to be pressed against cutting edge 101 of knife 91'. This frees the trailing portion of the loop so that it will notbe cut. This would result in a staggered arrangement of the yarn ends as shown in Fig. 14, except for the controlled action of 'the presser foot runners and 106.
At the time that the leading portion of the yarn is cut as shown at 108 in Fig. 14, the uncut portion of the yarn is under tension. By adjustment of the amount of pressure on presser foot 104, the runners 105 and 106 can be caused to permit a controlled amount of backward movement of'the uncut portion of the loop by reason of the tension in the yarn at the instant when the loop is cut. When properly adjusted, the presser foot runners 105 and 106 will permit a limited amount of backward movement or Withdrawal of the cut end of the looped yarn under the runners 105 and 106 such that the cut lengths 109 will assume aligned symmetrical positions with respect to the row of stitching 19. This is shown in Fig. 15. This backward movement occurs immediately prior to the stitching of each length of cut yarn 109 to the backing cloth 25' by the row of stitching 19 which is formed by the sewing machine. The means for adjusting the pressure on presser foot 104 is conventional and is therefore notdescribed.
For rapid production, the backing cloth is preferably arranged in the form of an endless belt -Whose maximum width is limited by the length of the overhanging arm 21 of the sewing machine. Successive rows of stitching will be formed in a helical arrangement without removing the backing cloth from the machine. After the backing cloth has been filled, the endless belt is cut to form an elongated strip as shown in Fig. 8. The strip is then cut into pieces to form two trapezoids B and C and two right isosceles triangles A and D which are stitched together as shown in Fig. 7 to form a larger piece such as a square of dense pile fabric, suitable for use as a rug. If desired, rectangular elements may be assembled in a conventio-nal manner.
If desired, the endless belt of backing cloth may be cut transversely to form suitable lengths with ends which are square or otherwise appropriately shaped and these lengths may be secured together to form a larger piece of pile fabric, such as a rug of any desired shape in which the rows of pile extend parallel to one of its edges, or in any other desired direction.
As may be seen in Fig. 13, the rotary loop holders 97 and 93 are axially movable to an extent determined by the flexibility of the knives 91 and 92. Axial movement of the loop holders 97 and 98 will vary the relative lengths of the cut loops and this axial movement may be caused to follow a predetermined pattern such that a decorative pattern will be formed in the pile fabric, the decorative pattern being defined by relatively raised and depressed areas resulting from the different lengths of the cut loops.
If the limited amount of axial movement permitted by the knives 91 and 92 is insuflicient, the loop holders 97 and 98, together with their respective knives 91 and 92 may be slidably arranged in any desired manner for symmetrical or other lateral movement with respect to the row of stitching 19, to vary the relative loop lengths. The eccentric cam 33 (Fig. 1) may also be moved axially along with the loop holders 97 and 98 to vary the amount of travel of yarn guide 36 in accordance with varying axial spacing between the rotary loop holders 97 and 98. All of these axial movements may be controlled by pattern-control mechanism of the type used in connection with looms to obtain a decorative pattern. The pattern may also be defined in black ink on the back of a light colored backing cloth to assure proper correlation of the pattern to the endless belt so that the endless belt may be cut without destroying the decorative effect and with a minimum waste of material. Photoelectric scanning apparatus located in close proximity to the stitch forming mechanism may then be used to vary the loop length in each row of stitching in accordance with the location of the particular row on the backing cloth.
The form of the invention shown in Figs. 1, 3 and 5 in which the loops remain uncut after stitching may also be arranged for axial movement of the loop holders 64 and 65 together with their respective earns 58 and 59 to obtain a decorative pattern in a pile fabric consisting of closed loops.
Having thus described my invention, what I claim as new and desire to secure by Letters Patent is the invention as defined in the appended claims.
What is claimed is:
l. A loop-forming attachment for use with a fastening device of the type which comprises fastening means, work feeding means for feeding a backing sheet to said fastening means for fastening a series of transversely extending portions of a thread-like member to said backing sheet by securing means extending along the line of feed of said work feeding means during the course of passage of said backing sheet past said fastening means, said attachment comprising: rotary supporting means; two circumferentially extending series of loop holding members carried by said rotary supporting means, said two series loop holding members being axially spaced from each other on said rotary supporting means, said loop holding members being adapted to receive an elongated thread-like member which is zig-zagged between axially spaced loop holding members of difierent ones of said two series, said attachment being adapted to be positioned with said two series of loop holding members disposed on opposite sides of said line of feed for delivering said zig-zagged thread-like member along with said cloth to said fastening means; cyclically operative feeding means cooperating with said loop holding members for delivering and zigzagging said thread-like member between axially spaced ones of said members of said two series of loop holding members; and means for driving said rotary supporting means and said cyclically operative feeding means at predetermined speeds in fixed relationship to the feeding speed of said work feeding means.
2. An attachment according to claim 1, in which said rotary supporting means is axially movable.
3. An attachment according to claim 1, further comprising releasing means for releasing said thread-like member from said loop holding members after said thread-like member has become fastened to said backing sheet by said fastening means.
4. An attachment according to claim 1, further comprising loop turning means spaced from said fastening means, said turning means successively engaging the loops of a previously fastened row and turning said loops away from the area on said backing sheet where an adjacent row of loops is to be fastened, whereby successive rows of loops may be fastened in close proximity to each.
other to form a dense pile of loops extending outwardly from said backing sheet.
5. An attachment according to claim 1, in which said two series of loop holding members are symmetrically arranged with respect to said line of feed of said work feeding means.
6. An attachment according to claim 1, in which said zig-zagged thread-like member, after being fastened to said backing sheet, comprises loops with closed ends, said attachment further comprising sharp-edged cutting means cooperating with said rotary supporting means and said loop holding members for severing said closed ends to release said thread-like member from said loop holding members after operation of said fastening means.
7. A sewing machine attachment comprising: a pair of axially spaced rotary loop holder members adapted to be disposed on opposite sides of a line of stitching formed by work-feeding and stitch forming means; a plurality of loop supporting members carried by each of said loop holder members; means for driving said loop holder members in predetermined speed relationship with respect to the speed of rotation of said work feeding and stitch forming means; reciprocating yarn feeding means driven in predetermined speed relationship with respect to said loop holder means for delivering and looping a continuous yarn around said loop supporting members, said loop holder and loop supporting members being arranged to deliver said looped yarn to said stitch forming means to be stitched to a backing cloth, the speed of rotation of said loop holder members by said driving means being operationally so correlated to the speed of operation of said work-feeding and stitch-forming means that each portion of said yarn which crosses said line of stitching is stitched at least once to said backing cloth; and means for releasing said stitched looped yarn.
8. An attachment according to claim 7, in which said loop supporting members are symmetrically arranged with respect to the line of feed of said work feeding means.
9. 'An attachment according to claim 7, in which said rotary loop holder members are axially movable for varying the relative lengths of said loops in accordance with a predetermined pattern.
10. An attachment according to claim 7, in which said loop holder members have a common axis of rotation, each loop holder member being of drum-shaped configuration and each having a peripheral groove formed therein, and wherein each'of said loop supporting members consists of a pair of radially extending pins disposed on opposite sides of one of said grooves, and in which said releasing means consists of a pair of fixed knife members each guided in one of said grooves, each knife member having a cutting edge extending generally radially with respect to said common axis and lying substantially in a plane normal to said axis, each knife member being arranged to sever a loop of yarn supported by each of said pairs of pins carried by one of said rotary loop holder members as said pair of pins passes said cutting edge.
11. An attachment according to claim 10, wherein said stitch forming means comprises a presser foot under which said yarn passes, said cutting edges being positioned to out said looped yarn during engagement thereof by said presser foot and prior to the stitching thereof, the pressure on said presser foot being adjusted to permit controlled lateral movement of the yarn thereunder, whereby the free end of the severed unstitched yarn will be drawn back under said presser foot by an amount suflicient to bring the ends of the stitched cut lengths of yarn into alignment.
12. An attachment according to claim 11, wherein said presser foot comprises a pair of spaced runners which engage said yarn, said runners having relatively sharp edges for controlling the extent of said backward movement in accordance with the amount of pressure on said presser foot.
13. An attachment according to claim 10, in which each of said rotary loop holder members is of hollow drum shaped configuration and wherein each of said loop supporting members comprises a portion pivotally connected to one of said drums and a normally radially extending pin portion, said pin portion being movable inwardly with respect to said drum for releasing a loop of yarn, and in which said releasing means comprises a pair of stationary cams engaging said pivotal portions of said loop supporting members and maintaining said pin portions in radially extending position, said cams each having a portion cut away to permit said inward movement of one of said pin portions when said loop is to be released.
References Cited in the file of this patent UNITED STATES PATENTS 423,781 Landenberger Mar. 18, 1890 2,117,964 Karle May 17, 1938 2,128,484 Karle Aug. 30, 1938 2,450,695 Siefert et a1. Oct. 5, 1948 2,482,655 Cone Sept. 20, 1949 2,631,556 Seaman Mar. 17, 1953