US2400064A - Yarn-control mechanism for warp knitting machines - Google Patents

Description

R. BASSIST YARN-CONTROL MECHANISM FOR WARP KNITTING- MACHINES May 14,.- 1946.

Filed Nov. s, 1943 2 sheets sheet 1 INVENTOR Basssfi WNJOMUZ OP ATTORNEY f May 14, 1946.. R. BASSIST YARN-CONTROL MECHANISM FOR WARP KNITTING mcxmms 2 sheets-sheet 2 Filed Nov. 3, 1945 (III/II mar-r moveo v 58 J" PATTERI? CONTROL 71 INVENTOR Patented May 14, 1946 YARN-CONTROL MECHANISM FOR WARP KNITTING MACHINES Rudolph Bassist, New York, N. Y., assignor of forty-five per cent to himself, ten per cent to Harold K. Stern, twenty-two and one-half per cent to Edith Abrams, and twenty-two and Edith April, all of New one-half per cent to York, N. Y.

Application November 3,- 1943, Serial No. 508,820

9 Claims.

My present invention relates generally to knitting machines and has particular reference to so-called warp knitting machines.

While certain phases of my invention are not necessarily restricted in their applicability to any particular kind of warp knitting machine, the general object of the invention is to provide certain improvements in high-speed knitting machines oi the so-called Tricot type. These machines are of relatively high gauge, employing approximately 28 to 34 needles per inch, and operating at rates of speed up to about 600 courses or stitches per minute.

In a warp knitting machine, the yarn is initially wound on one or more warp beams and is directed in parallel rows to a bank of needles which operate in a predetermined intermittent manner to interengage the threads to produce a knitted fabric of the jersey type. The yarn is directed to the needles by one or more guide bars through which the individual strands are threaded and by means of which the threads are looped around the needles or otherwise subjected to their operation, in a predetermined manner and sequence depending upon the particular pattern or style of knitted fabric which is to be produced.

In order that my invention may be better understood, I will preface this description by outlining, in a general way, the mode of operation and cooperation of the main parts of a warp knitting machlne.

A main driving shaft (hereinafter referred to as a cam shaft) is associated with means for intermittently moving the needles through the knitting cycle. Generally speaking, thi movement is an up-and-down movement. Thread is suitably looped around the needles while they are in their upward positions, and when the needles move downwardly they perform a, knitting opera--' tion, with the aid of a presserbar," a "sinker," and other suitable auxiliary parts which are well known per se. Each guide baris provided with a corresponding number of needles through which the strands coming from the warp beam are threaded. Actuated by the cam shaft is a means for imparting a predetermined intermittent movement to the guide-bar, one component of movement being a transverse or swinging movement in a substantially forward-and-back direction, the other component of movement being longitudinal. These movements of the guide-bar are so timed and controlled. relative to the needle operation, that the strands, are suitably loop d around or otherwise subjected to the action of the needles to chine, one of the shortcomings has arisen from in accordance with a predetermined pattern.

For examplefassuming that only one warp beam is employed, the guide-bar may be moved so as to loop a strand around one needle during one course, around an adjacent needle during the next course, and so on. Or, depending upon the fabric desired, the guide-bar may loop a strand direction to loop the strand around a third selected needle for the third". course, and so on. A

large number of different optional cycles are possible, depending upon the results desired in the finished product. In each case. however, the longitudinal movement of the guide-bar requires that a certain amount of yarn be made available to it, the exact amount being dependent upon the extent of the longitudinal movement of the guidebar; and during each forward-and-back or swinging movement of the guide-bare. relatively reduced amount of thread should be made available to it. The greater the accuracy with which the yarn feed corresponds to the moment-tomoment fluctuating yarn demands of the guidebar. the more smoothly and emciently will the machine operate.

' The machine may employ either one, two or three warp beams, possibly more. The simplest type of fabric is produced by the employment of' only a single warp beam. A different type of fabric would result from the employment of two warp beama itibeing understood that there is usually a separate guide-bar for each warp beam. Where a ."filler" thread, or more accurately, an

unknitted warp thread, is to be associated with the fabric for the purpose of forming loops or and to the strands of the ground fabric, in a predetermined manner.

For the sake of simplicity, the features of the present invention will be described in connection with a single warp beam and a single guidesbar. although it will be understood, as hereinbefore pointed out. that mor than one warp beam may be employed if necessary or desirable.

In the conventional type of warp knitting mathe fact that the threads are drawn from the warp beam by a pulling action initiated by the needles themselves and by the guide-bar which controls the disposition of the yarn with respect to the needles. The warp beam is generally provided withsome sort of brake equivalent clutch mechanism operated by the pull of the yarn, whereby the warp beam is released for rotation whenever the knitting cycle call for thread, and whereby it is secured against rotation in the interim periods. This arrangement has numerous disadvantages and imposes severe limitations upon the knitting operations. For example, the interdependence between yarn feed and warp beam rotation restricts the types of fabric that may be produced. Also, any stoping or starting of the machine as a whole produce an irregularity in the knitting operation whereby an undesirable line or streak known as a stop-mark is produced in the fabric. The latter disadvantage often causes material impairment of the commercial value of the fabric, and it manifests itself most frequent in the highspeed machines to which my invention has primary reference, and in cases where the yarn is of the relatively slippery character of rayon or the like.

In my Patent No. 2,303,903, I disclosed a means whereby these disadvantages, and others, are successfully overcome, one of the characterizing features of the improved machine residing in the fact that the warp beam is continuously rotated in yam-feeding direction in a predetermined timed relationship with respect to the knitting cycle, but independent of any pulling action upon or by the yarn itself.

In my Patent No. 2,334,058, I described a further improvement and refinement of this general type of machine, whereby there is imposed upon a continuously rotating warp beam a regular fluctuating component of movement intended to synchronize the thread feed with the fluctuating requirements ofthe needles and guidebars. I disclosed the employment in the warp beam transmission, of a mechanism (exemplified by a pair of meshing non-circular gears) which comprises rotating driving and driven members wherein a fluctuating angular velocity is imparted to the driven member relative to that of the driving member.

In my Patent No. 2,361,526, I described certain further improvements by means of which an even wider range of adjustments wa provided for in the timing of the thread feed and'its synchronization with the yarn requirements of the guidebars and needles.

- It is the principal object of the present invention to provide certain further refinements in this general type of warp knitting machine. whereby further accuracy of synchronization may be effected, whereby the smoothness and efficiency of operation, even at relatively high speeds and for protracted periods, may be enhanced, and whereby there may be provided in a warp knitting machine, operating as hereinbefore described, a delicately controlled automatic stop mechanism designed to halt the machine in case of thread breakage or thread failure.

One feature of the present improvement consists, in brief, of an adjustable mechanically-operated'means for takin up d releasing. in a predetermined manner, the thread which is being fed from the warp beam to the knitting instrumentalities. This is not to be confused, howtake-up, because obviously no such continuous take-up or thread tensioning may be employed in a machine, like the present, in which the thread is positively fed or directed from the warp beam to the needles, as distinguished from a machine or mode of operation in which the thread feed is brought about by a pulling action upon the thread.

The present mechanically-operated thread take-up and release mean is controlled and driven by the cam shaft of the machine or by any other suitable driving instrumentality operating in timed relation to the main drive. It is to be understood that the term mechanically-operated" includes within its significance any electrical, magnetic, or other means of actuation and is intended merely to signify a positive type of operation as distinguished from the purely negative and continuous action of an ordinary springever, with any ordinary type of resilient slack actuated or otherwise resiliently-controlled mechanism.

The advantages of this improvement will be pointed out hereinafter, and reference will be.

made to some of the circumstances under which it is intended to be employed.

Another improvement forming part of the present invention appertains to the automatic stopping of the machine in case of thread breakage or thread failure. Its usability and advantages are directly attributable to the mechanical thread take-up and release means hereinbefore mentioned, because of the leveling effect of the latter upon undesired transverse thread movements or vibrations. So far as I am aware, an automatic stop mechanism of the present character has never before been employed or even deemed to be applicable in a warp knitting machine. Briefiy, the present improved structure consists of a delicately-poised feeler associated with each thread in such a manner that thread breakage or failure automatically disturbs the balance so as to effect an instantaneous stoppage of the machine.

I achieve the foregoing general objects and advantages, and I provide for the embodiment of the tion of Figure 4 and Figure 6 is a. diagrammatic view showing the relationship between certain driving and driven parts of the machine and certain electrical controls.

I have omitted a showing of a warp knitting machine as a whole, since the present invention may be adequately described and illustrated by itself. The general type of warp knitting machine to which my invention relates is illustrated in Figures 1, 2 and 3 of my aforementioned Patent No. 2,334,058. Briefly, the machine is provided with a bank of needles and at least one guide-bar which cooperates with them-in performing the knitting operations. The needles are intermittently moved in a general up-and-down direction,

. my aforesaid patent.

the motive power being derived from a main driving shaft or cam shaft. The guide bar has two types of movements, one of which is a swinging or back-and-forth movement, the other of which is a reciprocatory longitudinal movement. Both of these movements are brought about by the motive power of the cam shaft. the swingingmovement being generally accomplished by an articulation of parts as shown in Figure 2 of my aforesaid patent, the longitudinal movements being effected with the aid of a pattern wheel or similar instrumentality such 'as that shown in Figures 1 and 4 of said patent. The machine is also provided with at least one warp beam which is positively driven by a transmission which derives its power from the cam shaft. In the preferred embodiment, this transmission includes a change-speed device, whose general nature and mode of operation are well known per se, such a device being illustrated in considerable detail in The change-speed device has a driving shaft and a driven shaft, and is also provided with an adjustable member or rod whose operation alters the relation between the angular velocities of the driving and driven shafts.

Referring now to Figure 1 of the present drawings, the cam shaft of the machine is designated by the reference numeral Ill, and I have illustratlvely shown a thread H which is travelling from right .to left as viewed in Figure 1. This thread may be assumed to be emanating from the warp beam (not shown) and to be advanced ultimately to the needles and guide-bar. It will be understood that a multiple number of such threads are travelling atone time in the manner indicated. Thus, while I have shown a single thread ii in Figure 2, and have shown it passing between two adjacent upstanding teeth l2 of a comb it, it will be understood that a. similar thread is simultaneously travelling through each pair of adjacent teeth l2.

' will serve to take. up and release a predetermined amount of slack in the thread or yarn. In accordance with my invention, and for purposes which will hereinafter be described in greater detail, this take-up and release of slack is caused to occur in a predetermined manner during each 1 knitting cycle. By knitting cycle I refer to one The positively-driven or mechanically operated mechanism for taking up and releasing yarn, in accordance with my present invention, may assume various forms. A relatively simple embodiment is shown in Figure 1 and consists of an oscillating member l4 mounted for pivotal movement upon the shaft II which extends longitudinally across the machine. The member I4 is in effect a lever of the first class, and it is intended to rock upon the shaft I! as a pivot. The rearward arm of this lever is provided at its end with a follower or roller 18 which is held by means of a spring I! in contact with a cam l8 mounted upon the jack shaft ID. The latter shaft is continuously rotated by any suitable transmission operating in timed relation to' the main'drive of the machine, and I have illustratively shown sprocket wheels 20 and 2! mounted upon the shafts, l8 and I0, respectively, and a chain 22 which extends around these sprocket wheels.

The forward arm of the lever l4 serves as a carrier for at least one thread-guide member or roller, and I have illustratively shown a preferred construction in which there are two such members 23 and 24. These members are intended to cooperate with similar guidin members or rollers 25, 28 and 21. All of these guiding members extend longitudinally across the machine so that all the threads pass over and under them, as shown in Figure 1. The members 25, 2t and 21 are positionally fixed. while the members 23 and 24 are relatively movable. 75

complete cycle of operation of the needles and guide-bar, whereby one course of the resultant fabric is produced.

The relatively movable guide members 22 and 24 may be secured to the carrier l4 in any desired manner, but I have found it preferable to employ a resilient securing means. Thus, it will be observed that each of the members and 24 is mounted upon a shaft 28 journaled in bearings 2! which are constantlyurged downwardly by means of a spring 3!. This spring exerts its compressing force against a collar or shoulder 3i secured to the journal 29, and against a rel-' atively fixed shoulder 32 which is secured to the carrier H by means or a stud or similar adjustable fastening device 33. By adjusting the latter, the shoulder 32 may be shifted by slight amounts toward or away from the shaft 28, thereby effecting a corresponding increase, or decrease in the compressive power of thesprlng 30. This spring is purposely made of such a strength that it will not yield to I any appreciable extent when the guiding members 23 and 24 move downwardly (as viewed in Figure 1) to take up slack in the thread, otherwise the oscillating movements of the lever l4 would fail to fulfill the desired securement of the members 23 and 24 in the carrier arm, and it will be understood that these springs may under certain circumstances be dispensed with entirely.

In Figure 3 I have illustrated the possibility of effecting the desired take-up and release of slack by a slightly different type of mechanism which is positioned in its entirety below the level of the threads travelling forwardly across the machine from the warp beam to the needles. An oscillating member .or carrier I4 is in this case similarly mounted for pivotal oscillations on the shaft 25, and the rear arm is actuated by means of a'follower or cam (or equivalent mechanism) similar to the elements I! and II of Figure 1. The forward arm of the lever 34 is provided with an arcuate member-tithe are being concentric with the pivot Carried by the memher I! are a plurality of fingers 31, each of shaft or pivot 22.

Coniointly, the fingers 81 define at their outer ends 'an arcuate guide over which the threads '40 arecaused to travel on their way to the needles. A rocking movement of the lever 24 serves intermittently to increase and decrease the radius of this composite outer guiding surface, whereby a predetermined amount of slack may be taken up and released during each knitting cycle.

For the sake of simplicity of description, each of the oscillatable members 14 and 34 of Figures 1 and 3 has been shown in the form of a lever whose lever arms are of predetermined relative lengths. In each case, the shape and contour of the cam (or equivalent instrumentality) which causes the oscillations will determine the amount or magnitude of movement of the guiding members which take up and release the slack in the thread. In the preferred embodiment of my invention, however, the relative lengths of the lever arms are adjustable or variable during a continued operation of the machine as a whole, so that the magnitude of the thread take-up may be accurately varied in accordance with a predetermined plan or pattern, in a corresponding manner. To accomplish this result, the pivoted lever or carrier member is preferably formed as shown at the left of Figure 4 and is associated with an adjustable lever or mechanism as shown most clearly in this figure.

In Figure 4, the shaft H is intended to represent the shaft .l5 of Figure 1 or the shaft 35 of Figure 3, and the reference numeral 42 is applied to the rear lever arm of the oscillating carrier member. It makes no difference whether the forward portion of the member 42 is constructed as in Figure l, or as in Figure 3, or in any other desired manner, but it will be observed that the rear arm is provided with a longitudinal groove or slot 43' within which a roller 44 is' arranged. This roller is mounted at. the forward end of a rod 45 which is exteriorly screw-threaded as at 45 and which extends into a suitable bore 41 in the oscillatable member 48. The latter is mounted for pivotal or oscillative movements upon a shaft 49 and is provided at its rear end with a follower 50 which rides upon an actuating cam 5|, a spring 52 serving to keep the follower 50 in contact with the cam 5|. The cam 5| corresponds to the cam I8 of-Figure 1, and is constantly rotated or driven by a suitable transmission from the cam shaft of the machine.

Mounted upon the member 48 is a reversible motor 53 which carries on its shaft a small driving pinion 54. This pinion meshes with a relatively large gear 55 which is provided at its hub with a worm 58 engaging the threads 46 on the rod 45. The member 48 is suitably recessed as at 51 to accommodate the gear 55.

In a manner and for a purpose presently to be described, the motor 53 is caused to operate at predetermined times, either in one direction or the other, so as to impart a corresponding rotation to the gear 55. Through the intermediary of the worm 56 and the threads 46, this brings about a corresponding longitudinal movement of the rod 45 into or out of the bore 41, thus slightly reducing or slightly increasing the effective length of this rod, When the rod is shortened, the magnitude of the oscillatory movements of the roller 44 is slightly reduced, thus bringing about a corresponding reduction in the magnitude of oscillating movement of the member 42 and thus in turn bringing about a corresponding reduction in the magnitude of slack which is taken up and released. When the rod 45 is slightly lengthened, the magnitude of oscillating movement of the roller 44 is correspondingly increased by a slight amount and this in turn brings about a correspondingly increased oscillation of the member 42, and a corresponding increase in the magnitude of the slack which is taken up or released. This adjustability may be eil'ected during a continued operation of the machine, since it is entirely independent of the contour or relative proportions of the cam 5| The purposes and advantages of the present mechanism for positively taking up and releasing certain amounts of slack during each knitting cycle can best be described by reference to several specific illustrative circumstances.

(1) As has been pointed out, the mode of operation of a warp knitting machine is of such a character that during each knitting cycle a relatively large amount of thread may be required during one interval of time, While a relatively smallamount of thread may be required during a succeeding length of time. Thus, while the guide-bar is moving longitudinally, a relatively large amount of thread may be required, while the transverse or swinging movement of the guide-bar (to loop the thread around a predetermined needle) usually requires a lesser amount of thread. In as much as the basic feature of the'present type of machine lies in the fact that the thread is positively directed toward the needles by an independent actuation of the warp beam, .i.- e., by an actuation which is entirely independent of any pull exerted by needles or guidebar, it ,is important that proper amounts of thread be fed to the guide-bar and needles in accordance with their momentary requirements. The more accurately the thread feed is synchronized with the moment-to-moment requirements of the guide-bar and needles, the more smoothly will the machin operate, especially at high speeds.

Assuming, therefore, that in the simplest type of machine there is a direct connection between the cam shaft and the warp beam (with perhaps a speed reducer or the like and possibly a changespeed device, but with no special mechanism such as the non-circular gears illustrated in my aforementioned Patents Nos. 2,334,058 and 2,361,- 526, it is obvious that the thread from the warp beam will be fed toward the needles at a uniform rate. As hereinbefore explained, however, the knitting cycle does not utilize thread at this uniform rate, and during each knitting cycle there is a momentary call for a larger amount of thread and a succeeding call for a smaller amount. This variation during each knitting cycle can be taken care of by means of the present mechanically-operated slack take-up so that the amount of thread available to the guide-bar and needles is accurately in synchronism with the requirements of the knitting cycle.

(2) As a second illustrative circumstance under which the present mechanical take-up device may be employed, let it be assumed that the transmission from the cam shaft to the warp beam includes a set of non-circular gears, such as the elliptical gears illustrated and described in each of my aforesaid Patents Nos. 2,334,058 and 2,381,526. These gears, similarly, serve the function of setting the tempo," as it were, of the thread feed to synchronizeit with the knitting cycle. It may happen, however, that because of manufacturing limitations the theoretical design of these non-circular or elliptical gears cannot be accurately carried out during the manufacturing process, especially where the machine is to operate at high speeds. As a result, thenon-circular gears (or equivalent mechanism) may prove to be slightly deficient in feeding the thread to the needles and guide-bar in exactly the accurate the machine or during its operation, that the variations in thread feed which are brought about by the non-circular gears or equivalent mechanism will be augmented or diminished, as the case may be, to the accurate amount desired.

brought into engagement with the fixed electric contact 5!.

(3) A third situation of similar kind may present itself where the rotation of the warp beam is regulated by a, special pattern control, such as the pattern chains shown in Figures 7 and 8 of my Patent No. 2,334,058, or the pattern control wheel shown in Figure 2 of my Patent No. 2,361,526. Here again, the limitations or special requirements of the manufacturing process may cause such pattern control to deviate slightly from the desired theoretical. For example, smooth operation at high speeds may require that the steps on the pattern control wheel. be merged more gradually with one another so as to avoid movements of too abrupt a character. Under such circumstances, the present mechanical takeup mechanism may be employed as an auxiliary means to compensate for such deviation.

(4) A fourth situation under which the'present mechanism may prove to be useful arises from the possible use of two or more guide-bars, each one regulating the manner in which thread from a separate warp beam is interengaged with the needles or with the threads of a ground fabric.

These guide-bars are arranged one behind the during that portion of the knitting cycle when it is again required.

The automatic regulation of the take-up, during continued operation of the machine, in accordance with the illustrative mechanism shown in Figure 4, may find utility under circumstances such as those illustratively shown in Figure 6. In this figure, I have illustratively shown a pattern-controlling mechanism similar to that shown in Figures 7 and 8 in'my Patent No. 2,334,058. A continuously travelling chain or chains (not shown) causes rods 58 and 59 to be individually moved downwardly at predetermined times. Downward movements of the rod 58 cause a lever (pivoted at 8|, to move into the illustrative position shown in Figure 6, in which the electric contact 62 (carried by the lever 60) is brought into engagement with the relatively fixed electrical contact 63. When downward pressure on the rod 5 8 is released, a spring 54 restores the rod 58 to its upward position and breaks the contacts 82, 63. Similarly, downward movement of the rod 59 causes a similar pivotal movement of the lever 65 which is pivoted at 58 and which carries an electric contact 51. The lever 65 is held in its normal position-by the spring BI, and when it is pivoted by the rod 59, the contact 61 is which derives its'power from the cam shaftof These electric contacts are arranged in a circuit which regulates a reversible electric motor I0. That is, when all contacts are broken, the motor I0 is idle and does not operate; when the contacts 62, 83 are in engagement, current from a suitable source II passes through the motor I0 to rotate it momentarily in one direction; and when the contacts 61, 69 are in engagement, current passes through the motor Hi to rotate it mo mentarily in the opposite direction.

The motor I0 may have its shaft I2 connected to the change-speed control of a change-speed device I3. This device has an input shaft I4 the knitting machine (either directly or through an intermediary transmission) and the output or driven shaft I5 may be connected through a speed reducer I5 to the warp beam 11.

This illustrative transmission, and the electric circuit shown, issubstantially the same as the corresponding mechanism and parts illustrated and described in my Patent-No. 2,334,058, and ailords a means whereby the continuous rotation of the warp beam may be slowed or speeded up during continued operation of the knitting machine, in accordance with a predetermined plan or pattern. Obviously, when the warp beam is speeded up, a larger amount of thread is fed to the needles during each knitting cycle, and when the warp beam is slowed, a relatively smaller amount of thread is fed to the needles durin each knitting cycle. Accordingly, the amount of slack to be reckoned with is slightly larger in one case than in the other, and for this reason it is desirable that the present slack take-up and release mechanism be automatically regulated as indicated in Figure 4, during continued operation of the knitting machine. This automatic regulation is preferably accomplished by connecting the motor 53 (Figure 4) with the electrical circuit of Figure 6, so that the motors 53 and in are arranged in parallel and operate together. That is, when the motor I0 is idle, the motor 53 is also idle; when the motor l0 momentarily rotates in one direction, the motor 53 does the same; and when the motor 10 momentarily rotates in the opposite direction, the motor 53 does the same,

for stopping the machine in case of an interruption oi. continued yarn travel. The means by which I prefer to accomplish this result is shown most clearly in Figures 1 and 2.

As hereinbeiore described, each thread II passes through two adjacent teeth l2 of a comb I3. Adjacentto this comb is a similar comb I8 provided with spaced partitions or teeth IS. The comb I8 is provided with a supporting ridge, adapted to support, in delicately poised positions, a plurality of make-and-break contact members 8|. It will be understood that there is onegof these members between each pair of adjacent partitions 19, although only one such member is shown in Figures 1 and 2.

The member 8| has a curved portion 82 which rests upon the ridge 80, and a forward arm 83 which is adapted to press upwardly against the thread The' rearward arm 84 is preferably composed of insulating material and carries an electric contact element 85 positioned in operative relation to a pair of bus-bars or electric contact members 86. The members 88 are suitably arranged in an electrical circuit which controls the cam shaft of the knitting machine, the arrangement being such that the establishment of a short-circuit between the members 86 will affect the electrical circuit in such a manner as to discontinue the operation of the cam shaft.

Under normal circumstances, each of the make-and-break devices 8| is poised in the position shown in Figures 1 and 2, whereby the contact element 85 is inoperative so far as the contact members 85 are concerned. So long as the thread continues to travel in an uninterrupted manner, its downward pressure on the forward 'arm 83 holds the element 85 in the normal inoperative position. The device 8| is so weighted, however, that if the thread breaks or fails, or for any other reason discontinues its pressure upon the arm 83, the device 8| will swing immediately into a position in which the contact element 8'5 short-circuits the members 88. After the machine has stopped, and after the operator has remedied the cause of'thread failure or inneedles and a guide-bar operated thereby, a warp beam, means independent of any pull exerted by needles or guide-bar for feeding yarn from the warp beam to the needles, an adjustable oscillatable member.actuated by the cam shaft in timed relation to the needle'and guide-bar operation for taking up and releasing slack in said yarn during each knitting cycle, and means for adjusting said member to vary the magnitude of its oscillations and thereby vary the magnitude of said slack take-up and release, said oscillatable member comprising a pivoted lever and said adjusting means comprising a mechanism for altering the relative lengths of its lever arms.

4. In a, warp knitting machine, a cam shaft, needles and a guide-bar operated thereby, a warp beam, means independent of any pull exerted by needles or guide-bar for feeding yarn from the warp beam to the needles, means operable during continued operation of the machine for varying the amount of yarn feed in accordance with a predetermined plan, adjustable mechanism actuated by the cam shaft in timed relation to the needle and guide-bar operation for taking up and releasing slack in said yamduring each knitting cycle, and means operating in timed relation to said yarn-feed-varying means for adjusting said a mechanism during continued operation of the terruption, the machine is ready to resume operation.

It will be understood that, for the sake of clarity, the present drawings are in man respects exaggerated and diagrammatic, and the details of structural proportions are not accurately depicted.

It will also be understood that the details herein described and illustrated are given merely by way of example, and that changes may readily be made by those skilled in the art without departing from the spirit and scope of the invention as expressed in the appended claims.

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent is: I

1. In a warp knitting machine, a cam shaft,

needles and a guide-bar operated thereby, a warp beam, means independent of any pull exerted by needles or guide-bar for feeding yarn from the warp beam to the needles, adjustable mechanism actuated by the cam shaft in timed relation to the needle and guide-bar operation for taking up and releasing slack in said yarn during each knitting cycle, and means for adjusting said mechanism during continued operation of the machine to vary the magnitude of said slack take-up and release.

2. I a warp knitting machine, a cam shaft, needles and a guide-bar operated thereby, a warp beam, means independent of any pull exerted by needles or guide-bar for feeding yam from the machineto vary the magnitude of said slack takeup and release.

5. In a warp knitting machine, a cam shaft, needles and a guide-bar operated thereby, a warp beam, means independent of any pull exerted by needles or guide-bar for feeding yarn from the warp beam to the needles, and mechanism actuated by the cam shaft in timed relation to the needle and guide-bar operation for taking up and releasing slack in said'yarn during each knitting cycle, said mechanism comprising relatively movable guiding members over which the yarn travels, and means for effectingan intermittent relative movement of said members.

6. In a warp knitting machine, a cam shaft, needles and a guide-bar operated thereby, a warp beam, means independent of any pull exerted by needles or guide-bar for feeding yarn from the warp beam to the needles, relatively movable guiding members over which the yarn travels, at least one of said members being positionally fixed, at least one other of said members being relatively movable, and mechanism for intermittently moving the latter, said mechanism being actuated by the cam shaft in timed relation to the needle and guide-bar operation whereby said intermittent movement takes up and releases slack in said yarn during each knitting cycle.

7. In a warp knitting machine, a cam shaft, needles and a guide-bar operated thereby, a warp beam, means independent of any pull exerted by needles or guide-bar for feeding yam from the Warp beam to the needles, relatively movablev guiding members over which the yarn travels, at least one of said members being positionally fixed,

at least one other of said members being relatively movable, an oscillatable carrier for the latter, and mechanism for oscillating said carrier, said mechanism being actuated by the cam shaft in timed relation to the needle and guide-bar operation whereby said oscillation takes up and releases slack in said yarn during each knitting cyc e.

8. In a warp' knitting machine, a cam shaft, needles and a. guide-bar operated thereby, a warp beam, means independent of any pull exerted by needles or guide-bar for feeding yarn from the warp beam to the needles,- relatively v movable guiding members over which the yarn travels, at least one oi said members being positionally fixed, at least one other or said members being relatively movable, an oscillatable carrier Ior said movable member, yieldable resilient means securing said member to said carrier, and mechanism for oscillating said carrier, said mechanism being actuated'by the cam shaft in timed relation to the needlenand guide-bar operation whereby said oscillation takes up and releases slack in said yarn during each knitting cycle.

9. In a warp knitting machine, a cam shaft, needles and a guide-bar operated thereby. a warp beam, means independent oi any pull exerted by needles or guide-bar for feeding yarn from the warp beam to the needles, relatively movable guiding members over which the yarn travels, at least one of said members being positionaliy fixed,

at least one other of said members beinarelatively movable, an oscillatable carrier for said movable member, yieidable resilient means securing said member to said carrier, mechanism for oscillating said carrier, said mechanism being actuated by the cam shaft in timed relation to the needle and guide-bar operation whereby said oscillation takes up and eleases slack in said yarn during each knitting cycle, and means for adjust ing the resilience of said resilient securing means.

RUDOLPH BASSIST.

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