US2143485A - Yarn tensioning for knitting machines - Google Patents

Description

Jan. 10, 1939. H. JANSSEN 2,143,435

YARN TENSIONING FOR KNITTING MACHINES 7 Filed May 24, 1937 4 Sheets-Sheet 1 Q I 672g 14' r, '9 v iii; if; 'FLEKL INVENTORZ 11614 314856 BY" TTORNEYI Jan. 10, 1939. H. JANSSEN YARN TENSIONING FOR KNITTING MACHINES Filed May 24, 1937 4 Sheets-Sheet 2 INVENTOR.

Jivnssezg TTORNE Jan. 10, 1939." I HJANSSEN 2,143,485

YARN TENSIONING FOR KNITTING MACHINES Filed May 24, 1957 4 Sheets-Sheet 3 IN VEN TOR. jienr Janssem BY 6? Y Arrows;

Jan. 10', 1939;

H.JANSSEN 2,143,485

' YARN TEN-SIGNING FOR KNITTING MACHINES Filed May 24, 1957 4 Sheets-Sheet 4 INVENTOR. Jim? Jameson,

mi. BY 1 ATM/W5;

Patented Jan. 10, 1939 UNITED STATES PATENT OFFICE YARN TENSIONING FOR KNITTING MACHINES Application May 24, 1937, Serial No. 144,365

15 Claims.

My invention relates to means for, and the method of, tensioning yarns, particularly between yarn feeding devices, such as snappers, and fabrics being knitted, as in full fashioned hosiery or straight knitting machines.

The feeding of yarn to the loop forming elements of a usual knitting machine is controlled by a snapper device which, after allowing the.

yarn to be freely fed to the knitting elements, is manipulated to take up the slack in the yarn between it and the fabric during loop forming movement of the machine. To aid the snapper in tensioning the yarn, a ring member is ordinarily provided, through which the yarn passes from the supply to the snapper. The ring hangs upon the yarn to apply a predetermined tension thereto, and, although a certain amount of slack is present, the ring maintains the yarn substantially taut between the supply andthe snapper. This slack in the yarn varies during the manipulations of the snapper but the ring aids the snapper in holding the yarn taut between the snapper and the fabric.-

If for any reason, such as variations in the yarn, vibrations of the machine or accidental slippage of the yarn through a snapper, a greater length of yarn is accumulated between the snapper and the fabric than can be taken up by the usual reverse movement of the snapper, loose end loops will be formed in the fabric.

Also, where a plurality of yarns are fed to the knitting elements in recurrent sequence, as in the three carrier ringless principle, each yarn, after being laid in one course, stands idle for two courses before again being fed to the knitting elements. With the yarn held in this manner and with the repeated manipulations of the snappers, yarn is accidentally drawn from the supply thereby allowing the rings to drop onto their respective support members, whereupon the tensioning action of the rings on the yarn between the yarn supply and the snappers is removed. The removal of this tension along with the excess yarn drawn from the supply while the carrier remains idle, increases the slack in the yarn to such a degree as to permit the idle threads to he accidentally caught by the end sinkers whereupon pullers are formed and defective fabric results. It is also apparent that each yarn, due to this excess slack, will be loosely fed to the knitting elements until such time when its ring is again raised to an effective position where it will be operative to apply tension to the yarn.

The usual ring tension structure, unless carefully attended, frequently becomes sticky because of the gum, oil or. moisture collected thereby from the yarn passing therethrough, and consequently the ring eventually sticks to the supporting wire and in turn becomes ineffective insofar as any tensioning action is concerned. Obviously, when this occurs on the machines of the prior art, no means is available for compensating for the slack in the yarn other than the snapper itself which is ordinarily incapable of satisfactorily compensating for slack in the yarn occasioned in the aforesaid manner.

Furthermore, the operation of the ring tensioning device depends entirely upon gravitational forces for its operation and consequently the speed of operation is a constant which has at times been found to be too slow for proper operation in connection with the present day high speed machines.

It is an object of my invention to provide a mechanism of simple construction which will be economical to manufacture and efilcient in operation, and which will satisfactorily overcome the deficiencies of prior art devices of this type.

Another object is to provide a yarn tensioning device will will be sufilcientlysensitive to permit its use on high speed knitting machinery.

Still another object of my invention is to provide a yarn controlling device for applying tension to the yarn during yarn feeding and for holding the yarn taut during loop forming movements of the machine.

A further object is to provide a yarn feed device adapted to take up the slack in the yarn, from the yarn feed device to the needles of the machine, where the yarn is-held for a plurality of courses while other yarns are being formed into'courses as in the alternating three carrier principle mentioned. 7 With these and other objects in view which will become apparent from the following detailed description of the fllustrative embodiment of the invention shown in the accompanying drawings, my invention resides in the novel elements, features of construction and arrangement of parts in cooperative relationship as hereinafter more particularly pointed out in the claims.

In the drawings:

Figure 1 is a cross sectional view taken through a full fashioned knitting machine, illustrating my invention and the associated yarn supp y and yarn feeding means;

Fig. 2 is an elevational view showing the snapper structure of Fig. 1 in one of its extreme positions;

Fig. 3 is an elevational view illustrating in full size a yarn tensioning device constructed in accordance with the present invention;

Fig. 4 is a view similar to Fig. 3, showing an advanced operative position and with certain of the parts being broken away to more clearly illustrate the invention;

Fig. 5 is a view of the invention taken in the direction of the arrows 5-5, Fig. 3;

Fig. 6 is a view similar to Fig. 3 illustrating a modified form of the invention;

Fig. 7 is a sectional view of the device shown in Fig. 6, with the parts thereof being shown in different operative positions;

Fig. 8 is a sectional View taken substantially along the line 8-8, Fig. 6; and

Fig. 9 is a perspective view illustrating the relation of a plurality of the devices of the invention in association with three yarn carriers operating in recurrent sequence.

In the drawings and description, only those parts necessary to a complete understanding of the invention have been set forth; further information as to the construction and operation of other elements not herein specifically pointed out, but which are usual and well known, being available in the pamphlet entitled Full Fashioned Knitting Machines, copyright 1920, and in the Reading Full Fashioned Knitting Machine Catalogues, copyright 1929 and 1935, published by the Textile Machine Works, Reading, Pennsylvania, and in a pamphlet entitled Knitting Machine Lectures, published in 1935 by the Wyomissing Polytechnic Institute, Wyomissing, Penna.

Referring to the drawings, and particularly to Fig; 1, the framework of a full fashioned hosiery knitting machine comprises a frame member II], a front beam II, a back beam 2, and a center bed |5 disposed transversely to the frame member ID.

A sinker head 20, comprising sinkers 2| and dividers 22, is arranged to cooperate with a bank of needles 25, carried by a needle bar 26, in forming the loops of a stocking fabric indicated by dotand-dash lines 23. The needle bar 26 is supported by an arm 21 secured to a shaft 28 which imparts a vertical movement to the needles. The mechanism for operating the shaft 28 and the presser mechanism which rocks the needles toward and from the sinker head 20 during the up and down movement thereof to effect the usual loop forming movements of the needles, is of well known construction and is not herein illustrated.

A yarn 30 is fed to the needles 25 from a supply bobbin 3| in a yarn box 32, which box is supported by a gallows or yarn box supporting bracket 33 secured to the machine frame. The yarn 30 passes from the bobbin 3| through an eyelet 36 secured in the top of the yarn box, over stationary guide rods 31 to a moistening trough 38. From the moistening trough 38 the yarn passes through a tension ring 4| which is slidably mounted on a guide member 42 fastened to the supporting bracket 33. A loop 40, formed at the bottom of theguide member 42, acts as a rest for, and

controls the lowermost position of, the ring 4|. The yarn 38 passes from the ring 4| through a snapper device 43, secured to a snapper shaft 44 by a screw 45, and around another guide rod 46 to a yarn guide finger 41 which is fixed to one of carrier 'rods 48 of the machine. The carrier rods are separately slidably mounted in individual bearings of a bracket 5| secured to the center bed l5.

Oscillatory movement is imparted to the snappers in timed relation to the needles 25 through a lever 52 having one end secured to the snapper shaft 44 and connected at its other end to a rod 53. The rod 53 is connected to a cam lever 56 which is pivotally mounted by a pin 58 on a bracket 51 secured to the back beam I2. The lever '56 has a follower 6| which is operated either by the regular knitting cam 62 or by the narrowing cam 63 depending upon the axial position of a cam shaft 64 on which they are secured; the follower 6| being biased toward the cams by a spring 66, one end of which is connected to the lever 56 and the other end to a shaft 61.

In producing a course of loops, the yarn is drawn from the supply bobbin 3|, through the moistening trough 38, the ring 4|, the snapper device 43 and the yarn guide finger 41, and is fed to the needles 25. As the yarn passes through the snapper device, the latter is operated so as to permit free movement of the yarn therethrough under the control of the low portion 62a of the cam 62; and at the end of the carrier travel, after the yarn has been fed to the full complement of needles, the snapper is raised from the position indicated in Fig. 4 to a point approximately midway between the positions indicated in Figs. 3 and 2 as controlled by the portion 62b of cam 62, whereupon the yarn again becomes anchored thereto and is drawn tightly around the last sinker 2| to which the yarn has been fed. As the needles move downwardly to draw the new course of loops through the previously formed course of loops, the snapper while continuing to hold the yarn also moves downwardly from the intermediate position to the position of Fig. 3 controlledby the portion 620 of the cam 62, at which time the needles have reached their lowermost cyclic position. During the subsequent return of the needles to the highest position in their operative cycle, the snappers also move to their uppermost position shown in Fig. 2 under the influence of the high cam portion 62d of the cam 62. Following this movement the roller 6| coacts with the low portion 62a of cam 62 to position the snapper as shown in Fig. 4, corresponding to the couliering operation. Thus the thread tension mechanism under the control of the cam 62 operates to maintain a desired degree of tension on that portion of the yarn extending between the snapper 43 and the stocking fabric 23 during the knitting cycle of the machine; whereas the cam 63 becomes aligned with the follower 6| and controls the operation of this mechanism when the machine operates through its narrowing cycle.

The snapper device 43, see Figs. 2, 3, 4 and 5,

'is provided with an eyelet 68, in one arm 1| of a snapper base or frame 12 mounted on the shaft 44. A second arm 13, also a part of the frame 12, has a forked free end, the prongs 14 and 15 of which carry eyelets 11 and 80, respectively, through which the yarn passes from the eyelet 68 in its path to the yarn guide finger 41. The arm 1| has a leaf spring 18 secured thereto, as by screws 81, which has an opening 19 adapted to receive the eyelet 11, thereby permitting the spring 18 to press the yarn against the top of arm 13 and hold that portion of the yarn taut which extends from the snapper through the yarn guide finger 41 to the fabric being knit. The spring 18 cooperates with a fixed rod 8| in the manner illustrated in Fig. 4 to release the yarn as the latter is fed to the needles of the machine during the usual couliering operation.

Preparatory to feeding the yarn 30 from the yarn supply 3|, through the snapper to the needles 25, the snapper is moved in a clockwise direction, by action of the normal knitting cam 62, the snapper shaft 44, and the intermediate linkage, from the position shown in Fig. 2, to the position of Figf4, the snapper moving away from the spring 18 to permit the yarn to pass freely through the snapper. Upon completion of the couliering after the desired length of yarn has been fed to the needles, the snapper shaft Ml moves the snapper 43 in a counterclockwise direction to the aforesaid intermediate position controlled by the cam portion 62b, whereupon the spring it again anchors the yarn to the snapper and tensions the yarn between it and the fabric. This action is ordinarily sufficient to control the feeding of the proper lengths of yarn to the needles and thenproperly tension the yarn between the snapper and the needles during the downward and upward travel of the needles coincident with the looping of the new loops through the old. However, certain uncontrollable conditions, such for instance as the vibration of the machine, tend to cause the yarn between the snapper and the needles to become slack whereupon a loose selvage results.

To supplement the action of the snapper and prevent the slackening of the yarn a third arm 82 is provided on the snapper frame it having a leaf spring 83 secured thereto, as by a screw 88. The spring 83 extends upwardly through an opening M in the arm 13 and is provided at its upper end with an extension 85 which carries an eyelet 86 through which the yarn is laced as it passes from the eyelet TI to the eyelet 80, respectively, provided on the prongs M and 15 of the arm 13. During the feeding of the yarn from the supply to the needles 25, the extension 85 of the arm 83 is drawn to a position between the arms it and 15 (Fig. 4). However, if for any reason such for instance as variations in the yarn or vibrations of the machine, a greater length of yarn is provided between the snapper and the fabric than can be taken up by reverse movement of the snapper, such greater length will be automatically taken up by the action of the spring arm 83. Thus the yarn is always held taut between the snapper and the fabric.

Figs. 6;7 and 8 show a snapper device 9| of modified form in which an arm 92 corresponding to the arm 13, is of hollow or channel sectionprovided with a top wall portion 93 for covering an opening 94, the top wall 93 preventing accidental entanglement of the yarn 30, with the upper end of the spring 83 as the yarn passes from the guide eve 68 to the guide eye 11.

Fig. 9 illustrates the use of three snappers 43a, 4131) and 430, on a snapper shaft 44a, each of construction similar to that of the snapper 43. These snappers are used to control the feeding of separate yarns 30a, 30b and 300 from bobbins 3|a, 31b and tile, over tension rod 31a, through a trough 38a and through rings a, Mb and Mo on guides 42a, 42b and 420, and in turn feeding the yarns in recurrent sequence through yarn remain idle, one at each side of the knitting sechas opened twice and closed once.

tion, while the third finger moves with the friction rod (not shown).

Also, during each stroke of the friction rod, the snapper shaft 44a is actuated to tilt all of the snappers 43a, 43b and 430 in unison, each from a position corresponding to that of Fig. 2 to a position corresponding tothat of Fig. 4.

However, since only one of the yarnguide fingers 41a, band 410 is laying yarn during any one stroke of the friction rod, and the snappers of the idle yarns, as well as that through which the yarn being laid is fed, are open as in Fig. 4, a slight amount of yarn is inadvertently fed through the inoperative snappers. Obviously when yarn is thus supplied to idle carriers, slack is formed which, however, in the present construction is automatically taken up by the springs 83a, 83b or 830 as the case may be.

As indicated in Fig. 9, each of the springs 18a, 18b and is hearing against the stationary rod 81a, parts of which are broken away in the figure for clearness of illustration, which position corresponds to the position of the snapper of Fig. 4, which is the position corresponding to the couliering operation.

At the same time, the yarn guide finger 41b is traveling toward the left of the machine (Fig. 9), drawing its yarn 30b, and the ring 4| b is in its uppermost position. Also, at this time, the yarn guide finger 41a. has just completed a stroke of the right, but since it has now been idle since the departure of the finger 41b from its right hand position and its snapper is open, the ring Ma has descended part way. Further, at this time, the yarn guide finger 410 has been idle for approximately one-and-one-half strokes of the friction rod, during which period its snapper These repeated operations of the inactive snapper unintentionally draw sufiicient yarn from the supply to create enough slack to permit the ring Me to rest on its support member 40c illustrated as a loop at the bottom of the double wire like guide 420. Similar supports 40a and 40b are provided for the other tension rings. Thus, continued accidental feeding of yarn through the inactive snappers is compensated for by the action of the springs 83a, 83b and 830, as the case may be, which consequently prevents the formation of free end loops.

stroke, the guide 410 is released for a stroke to the right to draw its yarn 30c through the snapper and the ring dlc, and the above described cycle is repeated. Thus, a method of, and means for, tensioning a single yarn, or a plurality of yarns in selective or recurrent sequence, are provided by which the yarn or yarns are severally or simultaneously held, advance movement is given to the holding means during each yarn laying movement, release of the holding means is effected while one or more of the yarns are fed, holding of the yarn is again effected and the holding means moved backwardly, and a relaxing effect in the yarn is offset as by tensioning it or deflecting it by means constantly tending totake up slack in the yarn.

Obviously a thread control device of this improvedconstruction may be employed either independently of, or in combination with, a ring tension arrangement with equal efficiency, inasmuch as the operation of the resilient slack compensator element is entirely independent of the auxiliary devices. The sensitivity, automatic operatlon and simple construction 'of-this device makes it particularly desirable for use on full fashioned knitting machinery, on which it will function efficiently regardless of the oil, water and other disturbing elements which prevent satisfactory operation of more complex units. In like manner, the fact that the present arrangement is spring operated, permits it to be employed satisfactorily on modern machinery the high operative speed of which frequently prevents the use of gravity operated devices.

This improved mechanism, in addition to being adapted for use on knitting machines operating on the alternating carrier principle, may likewise be employed effectively to overcome numerous other problems, such for instance as are frequently associated with the production of knitted fabric .made from high twist silk. The natural tendency of high twist silk is to double itself into snarls, which, if carried into the fabric, create defective fabric. Obviously, snarls in the yarn cannot be formed unless slack exists in the yarn, and since this device effectively prevents slackening of the yarn, it is apparent that defects in fabric resulting from snarls will be effectively eliminated.

This device is particularly effective in preventing the formation of loose loops on the last needle to which the yarn is fed in successive courses, which loops may be at the selvage edge of the fabric or at an intermediate point, such for example as at the inner edge of a high splice heel portion of a full fashioned stocking. Loose loops of this nature are particularly noticeable as well as undesirable at the jointure between normal weight and reinforced portions of fabric, inasmuch as the loose floating loops which extend from the fabric are readily snagged and formed into pullers by any object coming in contact therewith whereupon the fabric is correspondingly damaged. Consequently, since this improved device prevents the yarn from becoming slack, loose floating loops of the kind described will be eliminated, and the fabric produced will obviously be of an appreciably better grade than was hitherto possible.

The simple construction of the auxiliary yarn tensioning or slack compensator member embodied in this invention, permits the amount of take-up to be varied, simply by bending the resilient piece toward or away from the control rod 44, as desired. Furthermore, it is manifest that springs of different strengths may be interchangeably used in order to increase or decrease the degree of tension associated with this arrangement, as the case may be, without in any way departing from the concepts of the invention.

Of course, the improvements specifically shown and described by which I obtain the above results, can be changed and modified in various ways, without departing from the invention herein disclosed and hereinafter claimed.

I claim:

1. In a yarn tensioning unit for a knitting ma chine, the combination with mechanism including a base carrying yarn holding and releasing elements, said mechanism including said base and said elements being movable in the yarn feeding direction to release and provide for advance of the yarn and movable in reverse direction to hold and exert backward pull on the yarn, of means carried by said base for tensioning the yarn between said base means and a fabric being knitted.

2. A yarn snapper comprising a support, a pair of elements thereon by which the yarn is guided, means including a spring on the support for engaging and releasing the yarn before it passes said elements, and means on the support including a spring for deflecting the yarn between said elements to take up slack in the yarn between said engaging and releasing means and an element to which the yarn is fed.

3. A'yarn snapper comprising a support, a pair of eyelets thereon through which the yarn passes, means including a spring on the support for engaging and releasing the yarn before it enters the eyelets, and means including a spring and a. third eyelet through which the yarn passes at a position between the eyes of said pair for deflecting the yarn and taking up slack thereon between an element to which the yarn is fed and said first means.

4. In a knitting machine snapper tensioning device, the combination with a member through which yarn is fed to a fabric being knitted, a spring carried by said member for engaging and releasing the yarn, and a stationary element, movement of said member in the feeding direction of the yarn causing the spring to engage the stationary element to lift the spring off the yarn for feeding the yarn, reverse movement of said member causing the spring to engage the yarn and exert a backward pull on the yarn, of auxiliary means including a spring carried by said member for taking up slack in the yarn between said first spring and said fabric.

5. In a knitting machine, a snapper tensioning device comprising a member through which yarn is fed to a yarn carrier, a spring carried by said member for engaging and releasing the yarn, a stationary element, movement of said member in the feeding direction of the yarn causing the spring to engage the stationary element to lift the spring off the yarn for feeding the yarn, reverse movement of said member causing the spring to engage the yarn and exerting a backward pull on the yarn, a tension ring for floating position on the yarn between the snapper and a yarn supply, and means including a spring for tensioning the yarn between said first spring and the carrier.

6. In a knitting machine, a snapper tensioning device comprising a member-through which yarn is fed to a yarn carrier, a spring carried by said member for engaging and releasing the yarn, a stationary element, movement of said member in the feeding direction 'of the yarn causing the spring to engage the stationary element to lift the spring off the yarn for feeding the yarn, reverse movement of said member causing the spring to engage the yarn and exerting a backward pull on the yarn, a tension ring for floating position on the yarn between the snapper and a yarn supply, and means including a spring carried by said member for tensioning the yarn between said first spring and the carrier.

'7. -A yarn snapper comprising a support for pivotal movement about a horizontal axis, a generally horizontal arm on the support of hollow cross section having a forked free end, yarn guide elements carried by the prongs of the fork, a laterally deflectable spring mounted on the support and extending to a position adjacent to said prongs, and a. yarn guide element carried by the spring for deflecting the yarn toward the interior of said hollow section arm from a position between the prongs. v

8. A yarn snapper comprising a support for pivotal movement about a horizontal axis, a generally horizontal arm on the support of inverted substantially channel shape having a forked free end, yarn guide elements carried by the prongs of the fork, a laterally deflectable spring mounted on the support and extending to a position adjacent to said prongs, and a yarn guide element carried by the spring for deflecting the yarn toward the channel from a position between the prongs.

9. A yarn snapper comprising a body portion for mounting on a snapper shaft, a first arm on said body, an eyelet on said first arm constituting the entrance of the yarn to the snapper, a second arm on the body having a forked end and an aperture in the arm between the body and said end, a pair of eyelets in the respective prongs of the fork, the yarn passing through said entrance eyelet and said pair of eyelets, a spring mounted on said first arm for engaging the yarn over the first eyelet of the pair and responsive to movement of the snapper about the axis of the snapper shaft for engaging a stationary element and releasing the yarn, a third arm on the body, a spring mounted on the third arm and extending into said aperture of the second arm, and a fourth eyelet through which the yarn passes carried by the second spring for deflecting the yarn between the eyelets of said pair toward said aperture to take up slack between said first spring and an element to'which the yarn is fed.

10. A yarnsnapper comprising a body portion for mountin on a snapper shaft, a first arm on said body, a eyelet on said first arm constituting the entrance of the yarn to the snapper, a second arm on the body of hollow cross section having upper and lower fork prongs at its free end, a pair of eyelets in the respective prongs of the fork, the yarn passing through said entrance eyelet and said pair of eyelets, a laterally deflectable spring mounted on said first arm for engaging the yarn over the first eyelet, of the pair and responsive to movement of the snapper shaft for engaging an element and releasing the yarn, a third arm on the body, a second laterally deflectable spring mounted on the third arm and extending to position adjacent to said prongs, and a fourth eyelet carried by the second Spring adjacent to the prongs for deflecting the yarn between the eyelets of said pair toward the interior of said hollow section arm to take up slack between the first spring and a fabric being formed.

- 11. A yarn snapper comprising a body portion for mounting on a snapper shaft, a first arm on said body, an eyelet on said first arm constituting the entrance of the yarn to the snapper, a second arm on the body of inverted substantially channel shape having upper and lower fork prongs at its free end, a pair of eyelets in the respective prongs, the yarn passing through said entrance eyelet and said pair of eyelets, a laterally deflectable spring mounted on said first arm for engaging the yarn over the first eyelet of the pair and responsive to movement of the snapper shaft for engaging an element and releasing the yarn, a. third arm on the body, a second laterally deflectable spring mounted on the third arm and extending to position adjacent to said prongs, and a fourth eyelet carried by the second spring adjacent to the prongs for deflecting the yarn betweenv the prongs toward the channel to take up slack between the first spring and a fabric being formed.

12. The method of tensioning the yarns in a machine for laying a plurality of yarns in which one of the yarns is idle during the laying of another yarn, which comprises the steps of simultaneously holding the yarns and moving the holding means of each yarn in the direction of feeding the yarns to release the yarns with each yarn laying movement of the machine, simultaneously reversely moving the holding means of all the yarns to hold and exert backward pull on all of the yarns at the end of each yarn laying movement, and aifecting each yarn between its holding means and a fabric being formed to ofiset a relaxing efiect in the idle yarn caused by said movements thereof.

13. The method of tensioning the yarns in a machine for laying a plurality of yarns in recurrent sequence, which comprises the steps of simultaneously holding the yarns and moving the holding means of each yarn in the feeding direction to release the yarns upon each yarn laying movement of the machine, only one of the yarns being fed at each yarn laying movement, but all of the holding means acting as aforesaid and tending to simultaneously exert backward pull on all of the yarns at the end of each yarn laying movement, and the step of deflecting each yarn between its holding means and a yarn laying element of the machine to exert a compensating tensioning effect to offset a relaxing efiect caused by operation of the holding means on the inactive yarns.

14. A yarn tension snapper unit comprising a rockable base, a yarn guide on the base, a spring on the base responsive to rocking of the base for disengaging the spring from, and engaging the spring to, a stationary member to hold the yarn against, and to release the yarn from, said yarn guide, respectively, a second yarn guide on the base spaced from said first yarn guide in the direction of yarn feed, a spring mounted on said base, and a third yarn guide carried by said second spring movable relative to said base for exerting tensioning forces on the yarn at positions on the yarn after the yarn passes said first guide and before the yarn passes said second guide.

15. A yarn tension snapper unitcomprising a rockable base, a yarn guide on the base, an element movably mounted on the base responsive to rocking of the base for disengaging said element from, and engaging said element to, a stationary member to hold the yarn against, and to release the yarn from, said yarn guide, respectively, a second yarn guide on the base spaced from said first yarn guide in the direction of yarn feed, and means including a third yarn guide carried by, and movable relative to, said base for exerting tensioning forces on the yarn at positions on the yarn after the yarn passes said first guide and before the yarn passes said second guide.

HENRY JANSSEN.

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