Patent Publication Number: US-6907758-B2

Title: Circular knitting machine having at least one moveable thread guide

Description:
FIELD OF THE INVENTION 
     The invention relates generally to a circular knitting machine comprising a needle cylinder, at least one cylinder cam segment, a dial arrangement having a dial and at least one dial cam segment, an axis of rotation, which is coaxial with the needle cylinder and the dial arrangement, and at least one thread guide element intended to supply a thread, wherein the cylinder cam segment together with the thread guide element, and the dial cam segment can be rotated about the rotational axis relative to one another, and wherein the needle cylinder and the dial arrangement together with the thread guide element are disposed displaceable relative to one another and parallel to the rotational axis. 
     BACKGROUND OF THE INVENTION 
     In a known circular knitting machine of this type (DE 19 44 454 A1) the cylinder and dial cams, or respectively the segments which form same, are disposed around an axis of rotation so as to be rotatable relative to one another. This serves the purpose of optionally adjusting the dial cam to synchronous draft or timing and afterdraft or delayed timing, respectively, in order thus to withdraw the dial needles simultaneously with the cylinder needles or—when viewed with respect to the circumferential direction of the needle cylinder—somewhat later than the latter into their completely drawn-back position (couliering position). Moreover the entire dial arrangement is mounted displaceable parallel to the axis of rotation, so that the height of the dial arrangement above the needle cylinder alters and thus the stitch length of the knitted goods to be produced on the circular knitting machine can be adjusted. 
     A problem with circular knitting machines of this type, which has so far not been satisfactorily solved, consists in the mounting of their thread guide elements, which serve to supply threads to the individual knitting points or systems. If a height adjustment of the dial arrangement takes place, then the height of the thread guide elements or respectively of the entire thread guides should be correspondingly altered so that the eyes or the like on them substantially maintain their relative position relative to the dial needles. If on the other hand the dial cam is rotated relative to the needle cylinder cam, in order for example to move from synchronous timing to delayed timing, then the thread guides should not be also rotated but should substantially maintain their relative position relative to the cylinder cam. This applies irrespective of whether the circular knitting machines have rotatable needle cylinders and dials and stationary cylinder and dial cams, or stationary needle cylinders and dials and rotatable cylinder and dial cams. 
     In the known circular knitting machine of the type described initially, the thread guides and all their parts are secured for this purpose o a common holding ring which is secured with the aid of carrier rods disposed parallel to the axis of rotation on a carrier which is disposed above the dial arrangement. This carrier can be moved up and down together with the dial arrangement but, during rotary movements of the dial cam relative to the cylinder cam, maintains its position relative to the cylinder cam segments. Thus the desired positions of the thread guides are automatically secured. What is disadvantageous, however, is that a thread guide ring surrounding the dial cam is required, the carrier rods required for the suspension of said ring make the arrangement of further structural components, such as yarn stripers for example, largely impossible and both the thread guide ring and the carrier rods hinder free access to the dial cam. Up to now these disadvantages have had to be accepted since other known types of fastening for the thread guides (e.g. DE 29 34 694 A1, DE 39 20 408 A1) are either unusable in circular knitting machines of the type described initially or result in other serious disadvantages. These consist especially in the fact that the thread guides have to be adjusted individually and set again manually after a height adjustment of the dial arrangement and/or a relative rotation of the dial cam in relation to the cylinder cam, and this is complicated and time-consuming. Moreover, with these types of fastenings for the thread guides, no automatic adjustments of the dial cam and/or of the entire dial arrangement can be carried out with the aid of stepping motors or the like, and therefore no complex circular knitting machines can be realised in which these adjustments can be carried out when knitting is in progress. 
     OBJECTS OF THE INVENTION 
     In contrast to the above it is an object underlying this invention to so design the circular knitting machine of the type described above that, despite of the described adjustment possibilities, free access to the cams is possible. 
     A further object of this invention is to so design the knitting machine defined above that sufficient space for additional structural components such as yarn stripers or the like is provided even in case the described adjustments are possible. 
     Yet another object of the present invention is a design of the circular knitting machine described above in such a manner that, also in case that the described adjustment possibilities are given, no additional carrier ring is required for the thread guides. 
     SUMMARY OF THE INVENTION 
     These and other objects are solved in accordance with the present invention by movably mounting the thread guide element on the cylinder cam segment. 
     Because the thread guide elements are mounted displaceable on cylinder cam segments which are associated with them, the space above the dial cam can remain largely free. If the thread guide elements are pivotably attached to the cylinder cam segments in such a manner that they can be pivoted radially outwards into an out-of-action position, the access to the machine during repair and maintenance work is improved still further. 
     Further advantageous features of the invention arise from the dependent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in greater detail below with the aid of an embodiment and in conjunction with the accompanying drawings. These show: 
         FIG. 1  diagrammatically a vertical radial section through a circular knitting machine according to the invention; 
         FIGS. 2 and 3  each an enlarged detail of  FIG. 1 , with two different height settings of a dial arrangement and a thread guide; 
         FIG. 4  a detail corresponding to  FIGS. 2 and 3  but not quite so greatly enlarged, the thread guide having been pivoted into an out-of-action position; 
         FIG. 5  a front elevation, partially in section, of a holder and a lever mechanism, which is pivotably mounted on said holder, for a thread guide element according to a preferred embodiment of the invention; 
         FIGS. 6  to  8  sections along lines VI—VI to VIII—VIII of  FIG. 5 ; 
         FIGS. 9 and 10  each a diagrammatic front elevation, partially in section, of the circular knitting machine on a scale corresponding roughly to  FIGS. 2 and 3  and in two different relative rotational positions of a dial cam and a cylinder cam; and 
         FIG. 11  a diagrammatic plan view of a guiding part formed on a dial cam segment according to FIGS.  9  and  10 . 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     According to  FIG. 1 , a circular knitting machine contains a, preferably rotatably mounted, needle cylinder  1  which is mounted on a carrier ring  2  having external toothing  3 . The external toothing  3  engages in known manner with a driving toothed wheel which can be driven by gear parts, which are not shown, by means of a drive motor which is also not shown. The carrier ring  2  is rotatably mounted in a stationary annular base plate  4  which bears a carrier ring  5  which is also stationary and on which a cylinder cam is secured which is composed of a plurality of cylinder cam segments  6 , which are disposed distributed in the circumferential direction of the needle cylinder  1  and around a rotational axis  7  which is coaxial with said cylinder. One segment  6  of this type is present, for example, per knitting system of the circular knitting machine. 
     Above the needle cylinder  1  is provided a dial arrangement  9 , which contains a dial  10  and a dial cam which, like the cylinder cam, is composed of a plurality of dial cam segments  11 , which are disposed distributed in the circumferential direction of the needle cylinder  1 . The dial  10  is mounted on a dial carrier  12  which is mounted rotatable in a machine frame which is not shown in detail, whereas the dial cam segments  11  are secured in a stationary manner to a dial cam carrier  14  which is securely connected to the machine frame. It is clear that on the circumference of the circular knitting machine can be arranged at least one cylinder cam segment  6  and one dial cam segment  11 , preferably however a plurality of cylinder cam segments  6  and dial cam segments  11 . The needle cylinder  1  is fitted in known manner with cylinder needles  15  and associated control elements  16 , a selection of the cylinder needles  15  according to the pattern being possible with the aid of selection devices  17  such as electromagnets for example. Correspondingly, the dial  10  is fitted with dial needles  18 , which can be preferably also selected according to the pattern using means which are not shown. As for the rest, the cylinder and rib needles  15 ,  18  are provided in known manner with feet which are guided on preselected paths by cam portions which are secured to segments  6 ,  11 . 
     Furthermore the circular knitting machine is provided with first means which are not shown and by means of which the position of the entire dial arrangement  9  can be adjusted parallel to the axis of rotation  7  and relative to the needle cylinder  1 , in order to alter the axial spacing of the cylinder and dial needles  15 ,  18  and thus the size of the stitches of the knitted goods to be produced. Moreover, second means are present which are not shown and by means of which the dial cam segment  11  (or respectively all the dial cam segments  11  present simultaneously) and the cylinder cam segment  6  can be rotated about the axis of rotation  7  relative to one another in order to adjust the dial cam to synchronous draft or afterdraft in dependence on the desired type of knitting. 
     Moreover, the circular knitting machine has on each knitting system at least one associated thread guide  9 , by means of which respectively at least one thread  20  coming from a supply bobbin can be supplied to the cylinder and dial needles  15 ,  18 . 
     Finally, the circular knitting machine can be additionally provided with adjusting members  21  (e.g.  FIG. 4 ) and  22  (e.g.  FIGS. 1 and 4 ) which make possible individual adjustment of the take-down depth of the cylinder or dial needles  15 ,  18  on each knitting system. Circular knitting machines of the described type are commonly known and therefore do not need to be explained in greater detail to the person skilled in the art. Reference is made by way of example in this context to the publications DE 19 44 454 A1 and DE 197 43 814 A1, which are hereby incorporated by reference as subject matter of the present disclosure, in order to simplify the illustration. 
     According to an embodiment of the invention, deemed to be the best one up to now, the thread guides  19  are mounted so as to be moveable, i.e. displaceable and preferably pivotable on cylinder cam segments  6  which are associated with them, as is explained in greater detail below with the aid of  FIGS. 2  to  4  in connection with one of the cylinder cam segments  6 . The other thread guides  19  present are expediently correspondingly formed and mounted. 
     In the embodiment according to  FIGS. 2  to  4 , the thread guide  19  is mounted with the aid of a holder  23  so as to be pivotable on the cylinder cam segment  6 . The thread guide  19  contains a lever mechanism  24  and a thread guide element  25 . The holder  23  is securely fastened to an upper end and to a side of the cylinder cam segment  6  lying radially on the outside. In a central portion, the holder  23  has a through hole  26  ( FIGS. 4 ,  5 , and  7 ) through which the adjusting member  21  is accessible. As especially  FIGS. 5  to  8  show, the holder  23  is provided in an edge portion surrounding the hole  26  with bores  27  for fastening screws  28 , by means of which it can be secured to the associated segment  6 . In an upper portion, the holder  23  is configured fork-like and provided with two parallel fork members  29 , which form a U-shaped receiver for a disc-shaped end portion  30   a  of a first lever  30  of the lever mechanism  24 . A pivot  31 , which protrudes through coaxial bores in the end portion  30   a  and in the two fork members  29 , serves the pivotable mounting of the lever  30  in the holder  23 . An imaginary longitudinal axis of the holder  23  here is substantially perpendicular to an imaginary longitudinal axis of the first lever  30 , whilst a pivot axis  32  ( FIG. 5 ) of the pivot  31  is substantially perpendicular to these two axes. In the mounted state of the thread guide  19 , therefore, the pivot axis  32  of the pivot  31 , as is apparent e.g. from  FIGS. 1 and 9 , is on the one hand perpendicular to the axis  7  of rotation, and on the other hand substantially perpendicular to an imaginary radius of the needle cylinder  1  or the dial  10 , said radius proceeding from the rotational axis  7  and being extended through the centre point of the pivot  31 . 
     According to  FIGS. 7 and 8 , the lever arm  30  is configured fork-like at an end portion remote from end portion  30   a  and provided with two parallel fork members  30   b  which form a U-shaped receiver for the one end portion  33   a  of a second lever  33  of the lever mechanism  24 . A pivot  34  which protrudes through coaxial bores in this end portion  33   a  and in the fork members  30   b , serves the pivotable connection of the two levers  30  and  33 , a pivoting axis  35  of pivot  34  being disposed parallel to the pivoting axis  32  of the pivot  31 . The articulation of the lever  30  with the holder  23 , effected by the pivot  31 , serves moreover the pivotable mounting of the entire lever mechanism  24  on the holder  23 , an imaginary longitudinal axis of the second lever  33  being disposed substantially perpendicular to the longitudinal axis of the first lever  30  and parallel to the longitudinal axis of the holder  23  in the mounted state and when the thread guide  19  is in the operating position. Moreover, the second lever  33  extends, according to  FIG. 7 , preferably above both the first lever  30  and the holder  23 . 
     As e.g.  FIGS. 1 ,  7  and  9  show, in the mounted state of the thread guide  19 , the first lever extends substantially radially inwards and the second lever  33  is disposed substantially parallel to the rotational axis  7  of the circular knitting machine. Therefore the lever  30  could also be described as a radial connecting rod in which pivot  31  is disposed radially outside and pivot  34  radially inside. By contrast, the lever  33  can also be described as a vertical connecting rod in which the end portion  33   a  is disposed with pivot  34  axially beneath and a further end portion  33   b  axially above. 
     As  FIGS. 5  to  8  also show, there is provided on the end portion  33   b  of the lever  33  a groove  37  in which one end of a slider or tangential holder  38  is mounted so as to be displaceable, specifically substantially in a direction parallel to the pivoting axes  32  and  35 . Moreover end portion  33   b  has an elongated hole  39  (FIG.  5 ), the long side of which is disposed parallel to pivot  31 , whilst the end of the slider  38  which is located in the groove  37  is provided with a threaded bore into which is inserted a fastening screw  40  which also protrudes through the elongated hole  39 . Thus the slider  38  can be moved backwards and forwards within limits determined by the edges of the elongated hole  39  and be fixed in a predetermined position by means of the fastening screw  40 . 
     At the other end of the slider  38  is secured an upper end of the thread guide element  25 . For this purpose, the slider  38  has there a groove  41  ( FIG. 5 ) and in its base a threaded bore, which is aligned with an elongated hole  42  ( FIG. 6 ) in the upper end of the thread guide element  25  and accommodates a fastening screw  43  protruding through this elongated hole  42 . Imaginary longitudinal axes of the groove  41  and of the elongated hole  42  are substantially parallel to the imaginary longitudinal axes of the second lever  33  and of the holder  23  and extended so far that the thread guide element  25  according to  FIG. 5  is disposed laterally beside the second lever  33 . With the aid of the fastening screw  43 , the thread guide element  25  can be moved up and down parallel to its imaginary longitudinal axis within the limits predetermined by the elongated hole  42  and be fixed in a preselected position. 
     The thread guide element  25  per se can be configured in any way at all. However it is particularly advantageous for it to be angled by approximately 90° at its lower end ( FIGS. 5 ,  6  and  9 ) along a narrow connecting web and thus be provided with a web  44  which is disposed substantially parallel to the pivoting axis  32  and which forms with the main part, disposed perpendicular thereto of the thread guide element  25  a narrow guide slot  45 , into which the thread  20  can be inserted in order to offer it to the knitting needles  15 ,  18 . 
     When the knitting needles  15  are used in the form of latch needles, web  44  is expediently configured as a latch opener or respectively a holding-open device for the latches of the needles  15 , so that it is ensured that the latches of the knitting needles  15  brought near in the direction of an arrow v ( FIG. 9 ) are opened before the thread guide  19  is reached, or are kept open. Such a design of the thread guide element  25  is expedient above all when the circular knitting machine on which it is mounted is equipped with automatic thread-changing devices (cf. e.g. DE 195 11 949 A1). 
     As for example  FIGS. 2 and 7  show, there is associated with each thread guide  19  a guiding part  46  attached to the dial cam, said guiding part being preferably secured to the associated dial cam segment  11  and protruding radially from said segment towards the outside. The guiding part  46  is provided with a guiding groove  47  which is represented in  FIGS. 2 and 3  in a broken line but in  FIG. 4  by a continuous line, said groove being configured here as a V-shaped groove which is open upwards. The guiding part  46  serves to bear and support a supporting member  48  which is formed on a part, which protrudes radially inwards and over the slider  38 , of the upper end portion  33   b  of the second lever  33 . The supporting member  48  preferably contains a protruding sliding element  49  which can be inserted into the guiding groove  47  and which consists for example of a bolt having an end which tapers conically downwards, and being glued or pressed into a bore in the end portion  33  or supporting member  48  and protrudes from same parallel to the lever  33  downwards, i.e. in the direction of the other end portion  33   a . The guiding groove  47  extends, as is clear for example from  FIGS. 9 and 10 , substantially perpendicular to the rotational axis  7  and perpendicular to the radial direction, i.e. substantially parallel to a tangent to the circle of needles of the needle cylinder  1 . By particular preference, the guiding groove  47  extends here along a circular path segment coaxial with the rotational axis  7  (FIG.  11 ), the radius of which corresponds to the spacing of the guiding groove  47  from the rotational axis  7  (FIG.  1 ). In  FIG. 11 , the curvature of the guiding groove  47  is represented disproportionately large. 
     According to a preferred embodiment, which can be seen e.g. in  FIGS. 2 ,  3  and  5 , the holder  23  has in its upper region a blind hole  50  which is parallel to its longitudinal axis and which opens out into the receiver, formed by the fork members  29 , for the end portion  30   a  of the lever  30 . On the base of the blind hole  50  is supported a spring  51 , here configured as a helical spring, which bears a locking ball  52  lying on its free end and tries to press said ball into the receiver for the end portion  30   a . The end portion  30   a  is here configured as a flat disc which is designed cylindrical on most of its circumference and provided with at least two index notches or recesses  53 , into which the locking ball  52  can enter when the end portion  30   a  is in the appropriate rotational position. The recesses  53  are preferably limited by guide surfaces  53   a  ( FIG. 3 ) which are configured in such a way, e.g. disposed in a V-shape, that the spring  51  attempts, after the locking ball  52  has snapped into one of the recesses  53 , to maintain, or respectively produce again after a deflection, a preferred rotational position of the end portion  30   a  in which the locking ball  52  assumes a centered position in the respective recess  53 . 
     The functioning of the described thread guide  19  is substantially as follows: 
     After the thread guide  19  has been mounted on the cylinder cam segment  6  in the described manner which is clear from the drawings, the second lever  33  is disposed substantially parallel to the rotational axis  7 . Now initially the thread guide element  25  can be so adjusted that the end of the guiding slot  45  guiding the thread  20  assumes an optimal position, relative to the knitting needles  15 ,  18 , for the insertion of the thread  20 . Here it is possible to proceed e.g. from the arrangement shown in  FIG. 2 , in which the axial spacing of the dial arrangement  9  from the upper end of the needle cylinder  1  is the smallest. The supporting member  48  is here in a position supported on the guiding part  46 , in which position the sliding element  49  lies in the guiding groove  47 . The guiding slot  45  can be adjusted relative to the knitting needles  15 ,  18  by the fastening screws  40 ,  43  being released, the slider  38  being displaced tangentially with respect to the circle of needles, and/or the thread guide element  24  being displaced substantially parallel to the rotational axis  7 , and the fastening screws  40 ,  43  being screwed tight again after a preselected position has been produced. In addition, the radial position of the thread guide element  25  relative to the rotational axis  7  could also be adjustable, by a further adjustment possibility being provided or appropriate washers being placed between the slider  38  and the thread guide element  25 . The circular knitting machine is now ready for operation. 
     If the height of the dial arrangement  9  above the needle cylinder  1  is to be altered, only the usual adjusting mechanism requires to be actuated for this purpose (e.g. DE 19 44 454 A1). The thread guide element  25  and the guide slot  45  automatically make the same, movement in the direction of an arrow w (FIG.  2 ), because the thread guide  19  is connected in an interlocking manner to the dial arrangement  9  on account of the guiding part  46  gripping under the supporting member  48  during upwardly directed axial movements of the dial arrangement  9 . Through this axial motion, the lever mechanism  24  is pivoted e.g. from the position according to  FIG. 2  into the position according to FIG.  3 . By suitable choice of the lengths of the levers  30  and  33 , of the arrangement of the thread guide element  25  on the thread guide  19  and of the position of the pivot  31  it can be achieved that the second lever  33  is only pivoted slightly in a radial direction and therefore the guide slot  45  substantially maintains its radial position relative to the cylinder needles  15  (cf.  2  and  3 ). This ensures that the thread  20  is securely inserted into the hooks of the cylinder needles  15  as they are withdrawn. Moreover, the guide slot  45 , after an axial displacement of the dial arrangement  9  (FIG.  3 ), assumes practically the same axial position relative to the dial needles  18  as in  FIG. 2 , such that the thread  20  can also be perfectly supplied to the dial needles  18 . 
     If the dial arrangement  9  is later lowered again for the purpose of reducing its spacing from the needle cylinder  1 , the thread guide  19  also makes this movement in the opposite direction to arrow w in FIG.  2 . This is firstly a result of gravity and secondly caused by the spring  51 . Since the end portion  30   a  of the lever  30  is rotated clockwise about the pivot  31  during a movement of the dial arrangement  9  in the direction of arrow w, the locking ball  52  here runs according to  FIG. 3  onto one of the guide surfaces  53   a  of the associated recess, with the result that the spring  51  is tensioned more strongly. As the dial arrangement  9  is lowered, the spring  51  then presses against the guide surface  53   a  and thus exercises a rotary moment in an anti-clockwise direction on the end portion  30   a , such that the thread guide  19  is coupled to the guiding part  46  by a frictional connection during this movement and is moved with said guiding part. Naturally other types of coupling are also possible. 
     For the function of the web  44  or respectively of the latch opener formed on same, the movement of the dial arrangement  9  parallel to the arrow w is not critical. It is merely necessary to form the parts intended to open, or respectively keep open, the needle latches so high that they are effective in each provided axial position of the dial arrangement  9 . 
     A substantial advantage of the described, and currently considered to be the best, embodiment consists in the fact that the thread guide  19  can be pivoted out of the operating positions according to  FIGS. 2 and 3  radially outwards into an out-of-action position according to FIG.  4 . For this purpose, it is merely necessary to raise the thread guide  19  slightly by hand in the direction of arrow w ( FIG. 2 ) until the sliding element  49  has emerged from the guiding groove  47 , and then to pivot it as a whole clockwise about the pivot  31 . In a desired out-of-action position, the locking ball  52  can then lock into a further recess  53  formed on the circumference of the end portion  30   a  (FIG.  4 ). This possibility of pivoting the thread guide  19  backwards and forwards is independent of the height at which the dial arrangement  9  is located and of the relative rotational position which the dial cam segment  11  assumes relative to the cylinder cam segment  6 . 
     Furthermore it is possible, as particularly  FIGS. 9 and 10  show, to rotate the dial cam segment  11  about the rotational axis  7  in the circumferential direction relative to the cylinder cam segment  6 . For this purpose again means which are known per se can be used (e.g. DE 19 44 454 A1).  FIG. 9  shows for example a position in which the needle cylinder  1  and the dial  10  operate with synchronised draft, i.e. in which the deepest points of the needle paths of the two cam segments  6 ,  11  lie vertically above one another. On the other hand,  FIG. 10  shows an adjustment to afterdraft (delayed timing) in which the dial cam segment  11  is displaced, as compared with the position according to  FIG. 9 , by several needle spacings (gauges) in the direction of arrow v. The thread guide  19 , however, remains unaltered in the position according to  FIG. 9 , because as the dial cam segment  11  is rotated, the guiding part  46  secured to same is also displaced in the direction of the arrow v and can slide along supporting member  48  ( FIG. 7 ) or respectively sliding element  49  of the thread guide  19  which cannot be displaced in this direction v, as is indicated by a broken line  47   a  in FIG.  10 . 
     The invention is not limited to the described embodiment which can be modified in many ways. This applies for example to the lever mechanism  24  in which the two levers  30  and  33  can also be securely connected to one another to form a one-piece part. In this case, appropriate choice of the lengths of the levers  30 ,  33  and of the position of the pivot  31  can again ensure that the position of the guide slot  45  (or any thread guide eye or the like) is only comparatively slightly altered when the dial arrangement  9  is displaced over the entire adjustment range provided for it in the direction of arrow w, and therefore does not have to be corrected. Furthermore, the thread guide  19  can also be coupled to the dial cam segment  11  by other means in the direction of the arrow w (or respectively in the opposite direction thereto). A reversal of the movements would also be conceivable, insofar as the cylinder cam segment  6  is rotated relative to the dial cam segment  11 , or respectively the needle cylinder  1  is moved together with the cylinder cam segment  6  axially relative to the dial arrangement  9 . Apart from this, the thread guide element  25  could be guided on the cylinder cam segment  6  so as to be axially displaceable instead of radially pivotable, in which case the pivot mechanism  24  would disappear and be replaced for example by a slip-in guide. In this variant also, the axial coupling could be effected by means of parts  46  to  49  and if necessary by means of additional springs or the like. Further, both variants can be provided, instead of with the engaging means  52  and  53 , with other locking means being easily operable and serving to fix the thread guides  19  at least in the operating positions. Insofar, the phrases “pivotable”, “displaceable” or, in general, “moveable” are to be understood in such a manner that the desired and described adjustments are possible without complicated manipulations and that at least after an unlocking of the locking means preferably also a central adjustment of the distance or the angular position between the cylinder  1  and the dial arrangement  9  can be carried out. Furthermore, in an advantageous manner stroke-limiting means can be provided which prevent unintentional pivoting of the thread guide  19  radially inwards or outwards. This purpose is served by e.g. two end stops  54  ( FIGS. 2  to  4 ) attached to lever  30 , between which stops an extension  55  attached to lever  33  is disposed. Thus the two end stops  54  fix the maximum pivoting range of the lever  33  when the end portion  30   a  of the first lever is in the locking position, which is also expedient in producing the out-of-action position according to FIG.  4 . Finally it goes without saying that the various features can also be applied in combinations other than those illustrated and described. 
     It will be understood, that each of the elements described above or two or more together, may also find a useful application in other types of constructions differing from the types described above. 
     While the invention has been illustrated and described as embodied in a knitting machine, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics or the generic of specific aspects of this invention. 
     What is claimed as new desired to be protected by Letters Patent is set forth in the appended claims.