CIRCULAR KNITTING MACHINE WITH KNITTING FUNCTION

Abstract

A circular knitting machine includes a needle cylinder rotating around a vertical axis and a sinker ring rotating with the needle cylinder. The needle cylinder has in its outer edge portion vertically controllable tip needles with needle hooks opened downwards as loop-forming elements, and for each tip needle, a surrounding sinker supporting the loop-formation is held movable in the radial direction on the sinker ring. Further, for each tip needle on the needle cylinder, a press sinker is kept on the sinker ring horizontally in radial direction, to close the hook tip of the tip needle by pressing the needle tip to the needle shaft. The press sinkers are each disposed on the sinker ring between two adjacent surrounding sinkers. The circular knitting machine allows needle wear to be reduced and a selection between weft knitting and warp knitting as loop-forming techniques is enabled in a single machine.

Claims

1-14. (canceled)

15. A circular knitting machine, comprising: a needle cylinder rotating around a vertical axis; and a sinker ring rotating with said needle cylinder; said needle cylinder having an outer edge portion and vertically controllable tip needles in said outer edge portion, said tip needles having needle hooks opened downwards as loop-forming elements and needle shafts; a surrounding sinker supporting loop-formation being held movably in a radial direction on said sinker ring for each respective tip needle on said needle cylinder; a press sinker held movably in the radial direction on said sinker ring for each respective tip needle on said needle cylinder to allow a closing of said needle hooks of said tip needle by pressing to said needle shaft; and said press sinkers each being disposed between two adjacent surrounding sinkers.

16. The circular knitting machine according to claim 15, wherein said press sinkers on said sinker ring are disposed between said adjacent surrounding sinkers on both sides substantially without clearance.

17. The circular knitting machine according to claim 15, which further comprises separating bars extended between said adjacent surrounding sinkers, said press sinkers each being guided on said sinker ring on said separating bars.

18. The circular knitting machine according to claim 15, wherein said surrounding sinkers have a side profile facing said needle and two horizontal support planes in side profile with an intermediate nose protruding in the radial direction.

19. The circular knitting machine according to claim 15, which further comprises a control device for individually controlling a radial displacement of at least one of said surrounding sinkers or said press sinkers.

20. The circular knitting machine according to claim 19, wherein said control device is configured to control said radial displacement of one or more of said surrounding sinkers or of all of said surrounding sinkers for guiding a new yarn toward said needle shaft before a retraction of respective tip needles to permit said tip needle to form loops of a weft knitted fabric.

21. The circular knitting machine according to claim 19, wherein said control device is configured to control said radial displacement of one or more surrounding sinkers or of all surrounding sinkers for guiding a new yarn past said needle shaft before a retraction of respective tip needles in a radial direction and thus for providing a yarn loop to permit said tip needle to form loops of a warp knitted fabric.

22. The circular knitting machine according to claim 15, which further comprises: a plurality of yarn feeders; said tip needles cooperating in a joint loop formation for a supplied yarn and each forming a loop-forming system; and each loop-forming system being adjustable in advance causing said tip needles to form loops either according to a weft knitting principle or a warp knitting principle.

23. The circular knitting machine according to claim 22, which further comprises: a sinker lock for guiding control feet of said surrounding sinkers and said press sinkers; said sinker lock configured to be changed for forming loops at said loop-forming systems either according to the weft knitting principle or the warp knitting principle.

24. The circular knitting machine according to claim 15, which further comprises: a plurality of yarn feeders; said tip needles cooperating in a joint loop-formation for a supplied yarn and each forming a loop-forming system; and each loop-forming system being adjustable in advance causing said tip needles to form loops, catch a supplied yarn or remain in a circular run.

25. The circular knitting machine according to claim 22, which further comprises a control device for controlling each loop-forming system to cause said tip needles to form the loops according to the weft knitting principle or the warp knitting principle or catch a supplied yarn or remain in a circular run.

26. The circular knitting machine according to claim 22, wherein said tip needles of a loop-forming system carrying out a catching process are retracted earlier than in the loop forming process, causing said press sinkers to close said hooks of respective tip needles only when both a supplied yarn and a previous loop have been received within said hook.

27. The circular knitting machine according to claim 22, wherein said press sinkers belonging to said tip needles of a loop-forming system performing a catching process are not moved so close to said hook of a respective needle that they close said hook, so that both a supplied yarn and a previous loop are received within said hook.

28. The circular knitting machine according to claim 15, wherein said tip needle includes an upper needle part with a nose protruding to a side and a lower control foot part with a recess for receiving said nose of said needle part.

Description

[0025] In the following, an embodiment as well as further advantages and details of the present invention are described with reference to the attached drawings.

[0026] The FIGS. 1a to 1h (with enlarged representation in FIG. 1a) show the sequence of the loop-forming method according to the (weft) knitting principle in the circular knitting machine according to the invention.

[0027] FIGS. 2a and 2b each show the different positions of the loop-forming elements before pulling off the needle during warp knitting and weft knitting with the circular knitting machine according to the invention.

[0028] FIG. 3a shows the position of the loop elements during pulling off/retracting of the needle during the catching process, while FIG. 3b shows the needle movement curve during the catching process.

[0029] FIG. 4a shows a perspective close-up view of the edge portion of the needle cylinder with needles as well as corresponding surrounding sinkers and press sinkers and the corresponding sinker locks (in contrast to the circular knitting of FIGS. 2a and 2b, the sinker lock and sinker lock part are integrated in this case). FIG. 4b shows a detailed view of the weft knitting or warp knitting system in FIG. 4a.

[0030] FIG. 5 shows a cross-sectional view of the sinker ring and the surrounding sinkers and press sinkers supported thereon in a parallel section direction which is parallel to the tangential direction on the needle cylinder.

[0031] FIG. 6 shows a variant of a two-piece tip needle that can be used in the circular knitting machine, in two views, one with the two needle parts separated from each other and one in the composite state.

[0032] In FIGS. 1a to 1h, the loop formation according to the (weft) knitting principle is shown on a loop-forming system of the circular knitting machine according to the invention. FIG. 1a shows in enlarged representation the tip needle 2 in the needle cylinder. By appropriate guidance of its control foot 6 in a cylinder lock part 14, the needle is expelled in the vertical direction and removed. In FIG. 1a the needle is in the pulled-off state. In its hook tip, there is the previously formed “old” loop of the already produced knitted fabric. The needle 2 is now expelled upwards, while the old loop remains on the plane (the lower support plane) 3a of the surrounding sinker 3 and is held back by the nose 3c of the sinker profile. As soon as the needle 2 has reached its highest position, the surrounding sinker 3 stored on the sinker ring 19 is ejected outwards (to the right in the drawing) guided by the control foot 8 in the sinker lock part 10, see FIG. 1b.

[0033] In FIG. 1c, the needle 2 now passes the yarn guide 5 on its rotation path. Then, the surrounding sinker 3 in FIG. 1d is extended in the radial direction inwards (to the left in the drawing) in the direction of the needle and the new yarn 1 is pushed to the shaft from the is extended 3 above the upper support plane 3b in the direction of the shaft of the expelled needle 2.

[0034] The needle 2 is then pulled down/retracted in FIG. 1e, so that the yarn lying on the upper support plane 3b of the surrounding sinker 3 is received in the needle hook. Then, in FIG. 1f, the press sinker 4 is extended by appropriate guidance of its control foot 7 inwards in the direction of the needle, so that it closes the needle hook elastically by pressure from the outside. Now in FIG. 1g the surrounding sinker 3 is pulled back so far that its upper support plane 3b releases the new yarn 1, while the needle 2 is simultaneously pulled further downwards, so that the needle hook and with it the yarn 1 therein are pulled through the through the old loop which is still on the plane 3a. Subsequently, in FIG. 1h, the press sinker 4 is retracted and the pull-off process of the needle 2 is completed (loop-formation, “Kulierung”), whereby the looping process is completed and can start again in the position of FIG. 1a.

[0035] FIGS. 2a and 2b show two snapshots of a weft knitting or warp knitting process in the circular knitting machine according to the invention. FIG. 2b shows the position of the loop forming elements in the knitting process immediately before pulling off the needle 2 and thus corresponds approximately to the position in FIG. 1d (the needles and sinkers of the machine in FIGS. 2a and 2b differ slightly from those in FIGS. 1a to 1h). In FIG. 2a, the corresponding snapshot is depicted in the warp knitting process. The surrounding sinker 3 is extended further inwards (to the left in the drawing) in comparison to the weft knitting process and thus presents a yarn loop reaching from the needle shaft to the upper support plane 3b. While the yarn is kept under uniform tension as continuously as possible by appropriate means (such as a suitable feeder) in the knitting process in FIG. 2b with a view to a good quality of the produced knitted fabric, the yarn tension can be lower in the warp knitting process in FIG. 2a and can vary. The provision of the yarn loop by the further advancing of the surrounding sinker ensures a safe loop-forming process.

[0036] Both in the situation of the warp knitting process in FIG. 2a as well as in the weft knitting process in FIG. 2b, in the next steps, the needle hooks are closed by the press sinker 4, the needle 2 is removed and the new yarn 1 on the needle shaft or the provided yarn loop are thus received to be then pulled through the old loop.

[0037] The circular knitting machine according to the invention is therefore suitable both for weft knitting and for warp knitting. In fact, the machine may have an actuator 15 on the sinker lock 9, with which a sinker lock part 10 can be displaced, whereby the length of the ejection path of the surrounding sinker 3 is switched between a longer path for warp knitting and a shorter path for weft knitting. The sinker lock 9 screwed to the sinker lock support ring 12.

[0038] Due the option of switching between the weft knitting function and warp knitting function, the circular knitting machine according to the invention allows an efficient and safe processing of a variety of different yarns. In particular, the warp knitting function allows the use of more sensitive yarns due to the lower yarn tension in the process. In fact, the loop-formation in the warp knitting process according to FIG. 2a takes place in the two steps of providing a yarn loop and pulling the provided yarn loop through the old loop. In the first step, the yarn tension in the yarn loop first increases from friction point to friction point due to the rope friction principle and then, when the yarn loop is presented, drops back to zero. In the second step, when the yarn loop is pulled through the old loop, yarn sections of the yarn loop and of the old loop rub against each other, thereby increasing the yarn tension again.

[0039] In contrast, in weft knitting, the conveying of the new yarn through the yarn guide and the pulling of the yarn through the old loop are simultaneously carried out, whereby the corresponding yarn friction forces add up and together result in a significantly higher yarn tension. Such an addition of yarn forces does not take place in warp knitting due to the temporal offset of the two processing steps, whereby the maximum occurring yarn tensions are lower. The warp knitting process is thus more preserving for both the yarn to be processed and for the loop-forming elements of the circular knitting machine.

[0040] The presentation of the yarn loop in the warp knitting process also has the advantage that the loop-forming part in the cylinder lock is relieved. The loop-forming angles therein are less steep than for weft knitting, which in turn reduces the load on the needle guided in the loop-forming part. By using simpler loop-forming parts, needle foot fractures and needle head fractures can be avoided.

[0041] In order to allow patterns, the weft knitting or warp knitting systems of a circular knitting machine that can be used for weft knitting and warp knitting should also be able to be adjusted for circular running and catching.

[0042] During the circular running, the needle 2 simply remains in its circular running position by appropriate control of the lock parts and is not expelled at all. The new yarn 1 is not even received by the needle hook.

[0043] FIG. 3a shows the position of the knitting system in the catching process, more precisely during the retraction of the needle 2. After the needle 2 has just before been ejected so far that it has received the new yarn 1, both the new yarn 1 and the old loop remain in the needle hook when retracted.

[0044] The catching process can be controlled by appropriate control of either the needle retraction or of the displacement of the press sinker 4. Thus, an earlier retraction of the needle 2 can be adjusted so that the press sinker 4 closes the needle hook only when the opening of the needle hook has already passed the old loop lying on the plane 3a (which is therefore already inside the needle hook).

[0045] FIG. 3b shows the needle movement curves for the weft knitting process and the catching process side by side. While the solid line 16 represents the needle movement along the timeline during the weft knitting process, the interrupted line 17 shows the earlier retraction of the tip needle 2 during the catching process.

[0046] Another possibility to implement the catching process with the circular knitting machine according to the invention is to not at all extend the press sinker 4 on a selected knitting system to close the hook needle, but to maintain it in its retracted position without pressure contact to the needle hook. The corresponding control of the press sinker 4 is done, for example, by a suitable adjustment of the sinker locks on the respective systems.

[0047] FIG. 4a shows a perspective view of the needle cylinder 11 from the side (in the variant shown here, the sinker lock 9 and the sinker lock part 10 are integrated). In FIG. 4b, the section showing the knitting system with yarn guide 5 is shown in detail. In both figures, the tip needles 2, which are arranged in the entire circumferential range of the needle cylinder 11, are shown only in a partial portion of the cylinder circumference for clarity. The figures, in particular FIG. 4b, show in addition to the needles 2 and the surrounding sinkers 3 and press sinkers 4 also the yarn guide 5 belonging to the knitting site in the selected portion of the cylinder edge. The surrounding sinkers 3 extend from the sinker ring 19 from the outside to the inside between the needles 2 on the sinker guides arranged on the needle cylinder. The press sinkers 4 are each arranged between two adjacent surrounding sinkers 3 essentially without any clearance (see also FIG. 5) and thus directly face the corresponding tip needle. The tip needles are also arranged between the surrounding sinkers extending towards the sinker guides to the board guides, so that the surrounding sinkers serve as guides for both the press sinkers and the needles.

[0048] As shown in FIG. 5, the press sinkers 4 thereby require little additional space because even with a conventional circular knitting machine, in which tongue needles but no press sinker are used, the surrounding sinkers 3 are spaced from each other (so that they can be guided past by the needles when they are expelled). In such a conventional knitting machine, separating bars 18 are normally provided on the sinker ring 19 in the spaces between the surrounding sinkers 3 to avoid clearance between the surrounding sinkers 3. Such a machine can be modified to a circular knitting machine according to the invention by arranging the press sinkers 4 on the separating bars 18, reasonably with as little clearance as possible with respect to the adjacent surrounding sinkers 3. Alternatively, a respective surrounding sinker and press sinker could also share a channel delimited by corresponding separating bars. However, this would have the disadvantage that the separating bars should be as thin as possible in view of a high fineness, which would entail an increased risk of breakage of the separating bars.

[0049] Just like the tip needles 2 having needle feet 6, which run through appropriately pre-set lock channels during rotation, the surrounding sinkers 3 and press sinker 4 also each have sinker feet 7 and 8 which are guided in corresponding channels of the sinker lock part 10. By appropriate presetting of the needle locks and sinker locks, each knitting system can optionally be adjusted so that loops are formed either according to the weft knitting principle or according to the warp knitting principle, catches the new yarn only or remains in a circular running state. In FIGS. 4a and 4b, the switch between weft knitting and warp knitting function is carried out by the actuator 15 on the sinker lock with integrated sinker lock part.

[0050] The space-saving arrangement of the press sinkers 4 between the surrounding sinkers 3 allows a relatively high fineness of the circular knitting machine, i.e. a large number of needles per inch at the cylinder circumference. Another advantage of this space-saving arrangement is that a high number of knitting systems can also be arranged along the circumference of the needle cylinder. Thus, with a circular knitting machine having a needle cylinder circumference of 30 inches, more than 88 knitting systems can be provided, which corresponds to a high system density of 2.9 systems per inch (higher system densities up to 3.2 are also conceivable).

[0051] FIG. 6 illustrates another possible simplification, which is the use of two-piece tip needles in the circular knitting machine. Such a two-piece tip needle has an upper tip needle part 2′ and a lower control foot part 6′. The tip needle part 2′ extends from the needle hook at the upper end along the needle shaft to a nose protruding to the side, while the control foot part 6′ has a gap-like recess receiving the nose and has the contour profile required for receiving and guiding in the corresponding cylinder lock part. The needle part 2′ can then preferably be formed by simple forming a wire, which is bent at the upper end towards the needle hook and towards the nose at the lower end, while another method such as punching a sheet metal part can be used for the control foot part 6′. The nose of the needle part 2′ and the recess of the control foot part 6′ are engaged with each other, but are not limited in their form apart from this adapter function; in particular, the recess in the control foot part does not need to have a slotted or slit shape.

[0052] The use of two-piece tip needles can also bring about further cost advantages, if only the more cost-effective needle parts 2′ of the tip needles have to be replaced after wear. Depending on the selection of the manufacturing processes for the needle parts, a complete needle equipment of the circular knitting machine can be more cost-effective. This partition of the needle in two parts, optionally in combination with the optional insertion of the press sinkers 3 between the surrounding sinkers 4, also allows an even easier conversion of a circular knitting machine with wrap knitting function into a conventional circular knitting machine and vice versa.

[0053] Alternatively, the present invention can also be applied to circular knitting machines based on the principle of the so-called relative technology. In such machines, the surrounding sinkers are stored in the upper part of the needle cylinder between the needles. Therefore, this machine type does not require a separate sinker ring. The surrounding sinkers can be controlled vertically in height and at the same time perform a pivoting motion around their pivot point. This pivoting motion replaces the horizontal movement of a conventional surrounding sinker. As pressing elements for closing the needle hooks, pressing wheels arranged outside the needle cylinder circumference can be used here (one for each loop-forming system, respectively).

[0054] The structure of the circular knitting machine according to the invention is based on a further development of conventional circular knitting machines. The circular knitting machine according to the invention can be manufactured as an independent machine; however, it is also conceivable, for example, to expand a conventional circular knitting machine by simply adding press sinkers into the already existing gaps between the surrounding sinkers as well as by the replacement of tongue needles by tip needles or the replacement of needle parts of corresponding two-piece tongue needles and tip needles.

[0055] In any case, the invention provides considerable advantages with regard to the problem of needle wear. In addition, the machine according to the invention allows the choice between weft knitting and warp knitting as the loop-forming techniques within a single machine.

REFERENCE SIGN LIST

[0056] 1 yarn [0057] 2 needle [0058] 2′ needle part [0059] 3 surrounding sinker [0060] 3a lower support plane [0061] 3b upper support plane [0062] 3c nose of the surrounding sinker profile [0063] 4 press sinker [0064] 5 yarn guide [0065] 6 Control foot of the needle [0066] 6′ control foot part [0067] 7 Control foot of the press sinker [0068] 8 Control foot of the surrounding sinker [0069] 9 sinker lock [0070] 10 sinker lock part [0071] 11 needle cylinder [0072] 12 sinker lock support ring [0073] 13 cylinder lock [0074] 14 cylinder lock part [0075] 15 actuator for weft knitting/warp knitting [0076] 16 knitting curve [0077] 17 catching curve [0078] 18 separation bar [0079] 19 sinker ring