TWI859169B - Knitting machine needle and knitting system - Google Patents

Abstract

The invention relates to a knitting machine needle (1) comprising at least the following features: a hook (2) for the formation of loops, which limits the shank (3) in the longitudinal direction (z) of the shank (3) and which ends in a hook tip (4) and, a first drive section (33), which follows on from the hook (2) in the longitudinal direction (z) of the shank (3).

The knitting machine needle (1) has a predetermined breaking section (9) for separating the hook (2) from the first drive section (33). The predetermined breaking section (9) is formed by a section of the shank (3), which extends in the longitudinal direction (z). The predetermined breaking section (9) is located entirely in a first shank section (10), which extends in the longitudinal direction (z) of the shank (3) between the tip (4) of the hook (2) and the first drive section (33). In addition, a knitting system (15) is claimed, which comprises a knitting machine needle (1) with a predetermined breaking section (9).

Description

Knitting machine needles and knitting systems

The invention relates to a knitting machine needle and a knitting system. There are many different known knitting machine needles. Knitting machine needles are used in knitting machines and usually move in grooves of the needle bed of the knitting machine via one or more butts of the knitting machine needle. In this case, the butt of the knitting machine needle interacts with a cam on the knitting machine. Especially in the case of high-speed knitting machines, the knitting machine needle is subjected to strong acceleration forces. Knitting machine needles with a latch (latch needle) are often used. The latch performs many swinging movements, which together with the hook form a yarn loop. Due to the high dynamics of this oscillating motion, loop formation defects may be encountered in the case of high-speed knitting machines. Such defects are aggravated by the inevitable wear on the hook and latch. The hook and latch are arranged at the front end of the knitting needle and are connected to the butt of the knitting needle via the needle bar.

In certain types of knitting machines, collisions occur between the butt of a needle and a cam or a jacquard needle. In order to counteract or at least mitigate the occurrence of damage, it is proposed in JP62191888U and EP1424416A1 that the butt of a needle of a knitting machine is provided with a predetermined breaking point so that the butt breaks before significant damage occurs. A similar predetermined breaking point is described in CN2534208Y. The needle described in CN2534208Y additionally displays a notch in its rearward position in the bottom side of the needle bar below the needle latch position. Such a notch has the effect of reducing the tension of the yarn loop when the notch slides over the needle latch in its retracted position. This tension relief is encountered when the existing knitted material (preferably the preceding yarn loop) engages in this notch. In many knitting machine needle configurations, such tension relief notches are located below or immediately adjacent to the rearward position of the needle latch. These notches are not intended to break with any significant probability due to the forces exerted by the yarn on the hook.

DE1635837A1 shows a weaving needle with multiple sections on the needle bar, which are intended to prevent the transmission of shock waves from the needle butt to the hook. These sections can be constructed as sections with modified mechanical properties or as sections with a smaller weaving needle diameter. In each embodiment, the special section is located at the position with the maximum height on the needle bar. These sections are therefore not predetermined breaking points, because the probability of the needle bar breaking at these points is not high.

DE4320956A1 and DE19503048C2 show predetermined breaking points on sewing and knitting needles.

Recently, especially in the case of long and thin knitting machine needles, damage has occurred due to collisions between sections of the needle bar adjacent to the butt and cam.

The purpose of this invention is to solve this problem.

This object is achieved by the knitting machine needle of claim 1 and the knitting system of claim 13.

The knitting machine needle according to the invention comprises a hook for forming a yarn loop, which limits the needle bar in the longitudinal direction of the needle bar, i.e. starting there and ending at the hook tip. In the longitudinal direction of the needle bar, the hook is followed by a first drive section. The cam element of the knitting machine transmits the force for moving the knitting machine needle to the drive section of the knitting machine needle. The drive section can be constructed as a needle butt, which protrudes above the needle bar in the positive height direction of the needle bar. The drive section can be formed by a coupling position. In this case, the coupling element usually has a needle butt for the forces that move the knitting machine needle to act on the coupling position of the knitting machine needle in a known manner. Furthermore, the knitting machine needle according to the invention can include a needle latch. The needle latch can be pivoted to the needle bar in such a way that it closes the inside of the hook in the closed position and the tip of the needle latch points in the longitudinal direction of the needle bar towards the first drive section when the needle latch is in its rearward position. The needle latch can be pivoted to the needle bar by means of a hinge or a shaft via a pin formed on the needle bar.

The knitting needle according to the invention is characterized by a predetermined breaking section for separating the hook from the first drive section, the breaking section being formed by a needle bar section extending in its longitudinal direction. In the language of this document, a "section" extends over an infinitesimal distance in the longitudinal direction of the knitting needle. The predetermined breaking point is completely located in the first needle bar section, which extends in the longitudinal direction of the needle bar between the tip of the hook and the first drive section.

Surprisingly, it was found that the problem of damage to the needle bed and cam is substantially alleviated by such a predetermined breaking section, which manifests itself on the needle bar of the knitting machine needle and causes the breaking of the needle bar between the hook and the first drive section.

The predetermined breaking section extends over a non-infinitely small distance in the longitudinal direction of the knitting machine needle. If the movement of the knitting needle in the needle bed is obstructed or if the yarn loop fails to be pulled off, the knitting machine needle has a considerable probability of breaking in the predetermined breaking section due to the forces that can be transmitted by the yarn. As defined in this announcement, the needle bar of the knitting machine needle extends over its entire length. The needle bar can only be subdivided into different functional sections. The end section of the needle bar forms a hook and adjacent to this hook has a section that can come into contact with the yarn during knitting. Furthermore, the needle bar has a section (drive section or needle butt), through which the movement of the knitting machine needles is initiated. The section located between the above-mentioned sections is used, for example, to guide the knitting machine needles (in the needle bed) and to connect the above-mentioned functional sections. The predetermined breaking section will advantageously be located in the section of the needle bar that has the function of guiding and connecting the other functional sections. The cross-section of the needle bar can have different heights. Needle bar sections with different heights can be spliced to each other at transition points. The first transition point can be arranged in the vicinity of the drive section. The second transition point can be arranged close to the hook. In the backward position of the needle tongue, the second transition point can be separated from the tip of the hook in the longitudinal direction by a distance that is twice or three times the distance from the tip of the needle tongue. The distance between the second transition point and the tip of the hook can take any value between the above values.

The knitting machine needle may have a predetermined breaking section which is constructed in such a way that the hook can be separated from the first drive section by a force acting on the hook and said force is less than 80% of the force that causes permanent deformation of a completely identically constructed needle without the predetermined breaking point. This predetermined breaking section can in particular be constructed in such a way that the hook can be separated from the first drive section if an unusually large force acts on the hook in the negative height direction. It will be clear to a person skilled in the art that at least the diameter ("fineness") of the yarn is related to the breaking strength of the needle and the breaking strength is of course also determined by the fineness of the yarn. The fineness also determines the maximum diameter of the yarn to be used. The tensile strength of the yarn is of course also significantly dependent on the yarn diameter, so that the fineness is entirely a needle property that has a great influence on the organization of the predetermined breaking zone. The fineness (gauge) of a knitting machine needle can be determined by the thickness of the shuttle belt pierced by the knitting machine needle and can be measured in the width direction of the knitting machine needle. In the case of a 0.4 mm gauge needle, the force required to separate the hook from the first drive section can be in the range of about 5N to 1N, depending on how the predetermined breaking zone is constructed. A knitting machine needle of exactly the same construction will be permanently deformed at about 8N. The term "deformation" is here to be understood in particular as a general term including "bending". A special test to verify the suitability of the predetermined breaking section may consist in placing the needle with its bottom side (the side facing away from the butt in the direction of its height) on a table and first pushing the needle onto the table so that it hooks over the edge of the table until the hooked end part (front part) of the needle protrudes at least as far as the predetermined breaking section above the edge of the table. If a defined breaking force or bending force is applied to the hook, the needle shall break at the predetermined breaking section. If the force is increased further (see example above) and the needle deforms plastically but does not break, the suitability of the needle for the purposes of this announcement is questionable.

The knitting machine needle may have a predetermined breaking section which is completely located in a second needle bar section which extends in the longitudinal direction of the needle bar between the position of the tip of the needle latch in the rearward position of the needle latch and the first drive section.

The knitting needle may have a predetermined break section which is completely located in the third needle bar section, which starts in the longitudinal direction of the knitting needle from a point which is spaced two needle latch lengths from the pivot point of the needle latch in the direction of the first needle butt and ends in the longitudinal direction of the knitting needle at a point which is spaced three needle latch lengths from the pivot point of the needle latch in the direction of the first drive section, the needle latch length being the distance between the pivot point of the needle latch and the tip of the needle latch. This pivot point or bearing point of the needle latch may have a bearing seat in the needle latch in the form of a circular through-hole, into which the shaft or pin extends. The latch length can be measured starting from the center of this penetration hole. The latch tip is the point of the latch that is farthest from this center point, and the distance between the two points can represent the latch length. The specific definition of the position of the predetermined breaking section in the longitudinal direction of the knitting machine needle makes it possible to reduce the variations in the forces exhibited by a single sample of a large number of knitting machine needles, under which the bend hook is separated from the drive section. The predetermined breaking section can be located in the fourth or fifth needle bar section. The fourth needle bar section can extend from the pivot point of the latch to the second transition point. The fifth needle bar section can extend from the position of the latch tip in a rearward position to the second transition point. In the case of knitting machine needles without a needle latch (e.g. compound needles), the predetermined breaking section can be located in the sixth needle bar section as described below: The compound needle has guide means for a slide (hook closing element) which are spaced apart from the hook tip in the longitudinal direction and extend in the longitudinal direction towards the drive section. These guide means do not extend below the hook tip. As a result, there is a minimum distance in the longitudinal direction between the hook tip and the guide means. The sixth needle bar section can extend from 1.5 times the minimum distance to three times the minimum distance from the hook tip.

The knitting machine needle may include a distance from the starting point of the hook end of the knitting needle in the longitudinal direction of the needle bar to the first driving section, that is, a distance of at least 75 mm starting from the side of the first needle butt closer to the hook in the longitudinal direction.

The knitting machine needle may have a needle bar whose height at the highest point in the section where the latch pivots to the needle bar ("breast height") is 0.8 to 1.5 mm. This height is measured in the height direction. The knitting machine needle may have a needle bar whose height in the section where the predetermined breaking section is located is between 50% and 70% of the breast height.

The knitting machine needles may have a needle bar which is punched out of the strip material and may have a thickness of 0.3 to 0.6 mm or 0.7 mm in a section where its thickness still corresponds to the thickness of the strip material measured in the width direction.

The knitting machine needles may comprise a predetermined break section having a reduced bar cross section in a direction at right angles to the longitudinal direction. "At right angles to the longitudinal direction" refers in particular to the plane defined by the height direction x of the knitting needle and its width direction y.

A knitting machine needle may have a predetermined break section, which has a reduced needle bar cross section, the reduction in the cross section being achieved by a reduction in the needle bar in the height direction. Such a predetermined break section may have the advantage that, in the case of a stamping process, it can be manufactured simultaneously and without the need for a separate production step. The predetermined break section can therefore be produced economically. The reduction in the height of the needle bar can be carried out in the height direction from above and/or from below. However, it would also be conceivable to provide the needle bar with a recess (or recesses) which does not extend to the upper and lower sides of the needle bar or the predetermined break section. The knitting machine needle may have a predetermined break section which, at the point where the reduction in the cross section is the greatest, is reduced by a minimum amount of 10% and a maximum amount of 60% of the height or height dimension adjacent to the needle bar or adjacent to a needle bar section. Thus, at the thinnest point of the predetermined break section, 40% to 90% of the cross-sectional area (in a plane at right angles to the longitudinal direction of the needle) remains. In particular in the case where a plurality of notches penetrate into the needle bar from different directions (e.g. from above and from below), the reduction in the cross section or height may be distributed over different subsections of the predetermined break section (20% from above, 25% from below). The notch-shaped configuration of the cross-sectional reduction point in the predetermined breaking section enables a relatively precisely defined point to be obtained for separating the hook from the drive section. The stress concentration is found at the location of the predetermined breaking section. Additionally or alternatively, it is naturally also possible to reduce the width of the knitting needle. In this case, measures equivalent to the above-mentioned measures for reducing the height of the needle bar can be used.

The knitting machine needles can have a reduction in the needle bar which is triangular in height and has an aperture angle of 60° to 120°. An angle of 90° can be particularly advantageous. The three corners formed in the needle bar can be rounded. In the case of a smaller reduction in height, a radius for the rounding of at least 0.02 mm is advantageous; in the case of a larger reduction in height, the rounding can also advantageously be constructed with a radius of 0.35 mm or, for example, also 0.4 mm or 0.5 mm. The height reduction can also be constructed as a trapezoid, a step or another geometric shape. Based on the above information, the difference compared to an indentation becomes apparent, for example, when the indentation slides over the needle latch in its rear position, which can have the effect of relieving the tension on the yarn: such an indentation has a larger aperture angle and is flat, so as to allow easy entry and exit of the yarn. In contrast, most predetermined break sections are intended to induce a defined break at a defined position. Therefore, in such predetermined break sections, the aperture angle of the flank is smaller. Moreover, because of the specific shape that favors the predetermined break section, it is advisable to position such a predetermined break section in a position that is not suitable for a yarn-embossed pattern indentation: the yarn-embossed pattern indentation is located at a position on which the yarn slides off. Due to its shape, the predetermined breaking section can "trap" the yarn loops and endanger the knitting process. Therefore, as mentioned above, it is advantageous to position the predetermined breaking section, for example, behind the position of the tip of the needle latch in the backward position of the needle latch. Another consideration that is advantageous for positioning the predetermined breaking section in the backward section of the weaving needle is the lever effect: if the yarn loops, and in this case especially the yarn loops that have not yet been unhooked, transmit great forces to the interior of the hook, the distance from the hook increases the lever effect of these forces on the predetermined breaking section.

The knitting machine needle may have a predetermined breaking section, the material of which has a lower elongation at break than the section constituting the rest of the needle bar. The behavior of the knitting machine needle under overload can be selectively controlled by this configuration of the predetermined breaking section (in addition or as an alternative to height reduction measures or similar measures). When the loads significantly exceed the loads for which the knitting machine needle is designed, the different degrees of plastic deformation to which the material is subjected can be suppressed, in favor of selective breaking. The knitting machine needle is advantageously made of steel. In the case of steel, the elongation at break can be influenced by selectively adjusting the hardness or the microstructure. For example, the microstructure in the predetermined fracture zone may be selectively brittle and/or coarse-grained.

As already mentioned at the outset, the problem of needle bed and cam damage occurs primarily in knitting systems which involve the use of long, fine knitting machine needles at high knitting rates. In this announcement, the term "needle bed" is used as a general term for those parts of the knitting system which guide the needles during the knitting operation. These are in particular the needle cylinders and needle discs of circular knitting machines and the flat needle beds for flat knitting machines.

DE3311361A1 and DE102014118217A1 describe measures for further increasing the productivity of high-speed knitting machines and show examples of typical knitting systems with suitable knitting machine needles in the attached figures. The invention relates in particular to improvements in knitting machine needles and knitting systems suitable for the high speed requirements described in these publications. These two publications describe knitting systems with knitting needles that have a very long, very thin needle bar section between the hook and the first needle butt. According to the above two publications, the majority of this long and thin needle bar section is guided transversely (in the width direction of the needle) in the individual needle beds by sinkers rather than by the groove walls of the needle beds. Knitting systems of the above-mentioned type achieve high knitting performance and high precision. The contents of the above-mentioned two announcements are incorporated herein by reference, at least with regard to the shape of the knitting needles used and the configuration of the knitting needles and sinkers in the knitting system in question.

The knitting system according to the invention comprises a needle bed with guide means and at least one groove bottom, which are arranged to receive the knitting needles and to guide and support them in their longitudinal direction during their intermittent movements. A needle bed in the form of a needle cylinder, a needle plate or a flat needle bed, for example for flat knitting machines, may be suitable. The knitting needles are received in the grooves by the needle bed and are guided in the width direction of the knitting needles by the groove walls and supported in the negative height direction of the knitting needles by the groove bottom. In particular, the knitting needle does not have to be guided over its entire length in the width direction, but can only be guided in the rearward section of the knitting needle. In other sections of its length, the knitting needle can be guided in the width direction by other knitting tools (this is the case, for example, in the knitting systems according to the publications DE 33 11 361 A1 and DE 10 2014 118 217 A1). The same applies to the support of the knitting needle on the bottom of the groove.

Furthermore, the knitting system according to the invention comprises at least one cam element for transmitting force to at least a first drive section of a knitting machine needle seated in a needle bed. Typically, the butts of the knitting machine needles rise vertically from the grooves of the needle bed and are received in passage-type grooves (cam curves) in the cam element. Circular knitting machines typically have a plurality of cam elements, each of which defines a subsection of the distance traversed by the butt (of the coupling element) during one complete rotation of the knitting needle cylinder of the circular knitting machine. Due to this relative movement between the knitting machine needle and the cam element in the width direction of the needle, the cam element transmits the forces which move the needle in its longitudinal direction during the knitting operation in the circular knitting machine to the drive section or needle butt in question.

The subject matter of the invention comprises a knitting system having a plurality of knitting machine needles, wherein each of these knitting machine needles has the following characteristics for its part:

A hook for forming a yarn loop, which limits the needle bar in its longitudinal direction and terminates at the tip of the hook,

The first drive section is located after the bend hook in the longitudinal direction of the needle bar.

The knitting system according to the invention is characterized in that at least one of the knitting machine needles has a predetermined breaking section for separating the hook from the first drive section. The predetermined breaking section is formed by a first section of the needle bar extending in its longitudinal direction. The predetermined breaking section is completely located in the first needle bar section, which extends in the longitudinal direction of the needle bar between the tip of the hook and the first drive section.

Due to the predetermined breaking section, exceptionally high forces acting on the knitting machine needles in the negative height direction will lead to the hook being separated from the first drive section. As a result, these forces are not transmitted to the needle bar section adjacent to the cam element. Due to this measure, collision-induced damage to the needle bed and the cam element is prevented or at least reduced.

The knitting system according to the invention can be constructed so that the guide means and at least one groove bottom of the needle bed, at least one cam element, as well as the position of the drive section and the predetermined break section on at least one knitting machine needle are coordinated in such a way that during knitting, at least one knitting machine needle is at least intermittently raised out of the guide means so that the guide means at least intermittently no longer supports the predetermined break section of the at least one knitting machine needle. At least when the knitting machine needle is in the raised state, the predetermined break section is above the first cam segment. This special setting enables precise control of the behavior of the system if unusually high forces act on the hook or on the unsupported section of the knitting machine needle. High forces can then be applied to the relatively long lever from the bend to the intended break section. Since the intended break section is located approximately at the point where the knitting machine needles are supported from the needle bed, a well-defined break is likely to occur at or in the intended break section. In this case, it is also important that the intended break section is not located too far in the direction of the bend, because otherwise, due to the lever action, an undefined break could occur at the point where the knitting machine needles are again supported by the needle bed. If the intended break section is located completely within the support zone, an undefined break could occur at the edge of the needle bed. For example, if the yarn loops are not unhooked and are collected in the hook, great forces can be generated during fabric winding. In this case, the hook can quickly be subjected to winding forces that are 2 times or more than the usual winding forces.

The use of knitting needles according to the present publication is particularly advantageous with knitting systems of the type described in DE 3311 361 A1 and DE 10 2014 118 217 A1. Advantageously, the knitting system which is the subject of the present publication also has the additional properties of DE 3311 361 A1 and DE 10 2014 118 217 A1.

1: Knitting machine needles

2: Bend hook

3: Needle bar

4: Bend hook tip

5: Pin heel

6: Needle latch

7: Closed position

8: Backward position of needle latch 6

9: Predetermined breaking section of needle tongue 6

10: The first section of needle bar 3

11: The second section of needle bar 3

12: Tip of needle latch

13: The third section of needle bar 3

14: Pivot point of needle latch 6

15: Knitting system

16: Needle bed

17: Guiding mechanism

18: Cam element

19: Starting point of the hook end of the first stitch butt 5

20: Starting point of the hook end of knitting machine needle 1

21: Reduction in the cross-section of the needle bar

22: Needle bar cross section

23: The section adjacent to the planned fault section 9

24: The section adjacent to the planned fault section 9

25: Transverse flank

26: The height reduction shape of the needle bar height dimension in the z-x plane

27: Aperture angle with decreasing height

28: First Transition Point

29: Second Transit Point

30: The fourth section of needle bar 3

31: The fifth section of needle bar 3

32: Bottom of groove 32 of needle bed 16

33: Drive section

F: Strength

x: height direction

y: width direction

z: longitudinal direction

Figure 1 shows an overall view of a knitting machine needle.

Figure 2 shows an enlarged detail of the knitting machine needles in Figure 1.

FIG. 3 shows an enlarged detail of an alternative embodiment of a knitting machine needle similar to FIG. 2 .

Figure 4 shows an overall view of an alternative embodiment of a knitting machine needle.

Figure 5 shows an enlarged detail of the knitting machine needles in Figure 4.

FIG. 6 shows an enlarged detail of an alternative embodiment of a knitting machine needle similar to FIG. 5 .

Figure 7 shows an enlarged detail of the knitting machine needle of Figure 2, with the closed position of the needle latch and two cross-sectional views added.

FIG8 shows a symbolic representation of a knitting system according to the present invention.

FIG. 1 shows an overall view of a knitting machine needle 1. The drawings are not drawn to scale and details that are not necessary for the invention have been omitted. The other drawings have also been simplified accordingly. For the sake of clarity, a coordinate system has been added, which shows the directions defined on the knitting machine needle 1. The longitudinal direction of the knitting machine needle 1 is indicated by z, the width direction is indicated by y, and the height direction is indicated by x. In FIG. 1 , the hook 2 is located at the left end of the knitting machine needle 1 in its longitudinal direction z. Not far from the right end of the knitting machine needle 1 in FIG. 1 in the longitudinal direction z, the knitting machine needle 1 has a butt 5. (Also called drive section 33). The butt 5 protrudes above the knitting needle 1 in the positive height direction x. All figures show only one butt 5 on the knitting needle 1. However, in all embodiments, it is conceivable that the knitting needle 1 extends further to the right and has one or more further butts. The needle bar 3 of the knitting needle 1 extends between the hook 2 and the butt 5. The needle bar 3 has a clearly recognizable elongated design. In this embodiment, the length from the starting point 20 of the hook end of the knitting needle 1 to the starting point 19 on the hook side of the first butt 5 is approximately 78 mm. For the sake of clarity, three sections (10, 11, 13) along the length of the needle bar 3 of the knitting machine needle 1 are indicated by large brackets. The first section 10 and the second section 11 extend at their right ends to the hook side starting point of the first needle butt 5. In the third section 13, which is included in the first section 10 and the second section 11, a predetermined breaking point 9 is provided on the needle bar 3. This detail and other details can be more clearly identified in the enlarged view of the left-hand part of the knitting machine needle 1 in Figure 2.

In the enlarged view of FIG. 2 , in particular the hook tip (4) and the hook end 20 of the knitting machine needle 1 can be recognized. During knitting, the loop for loop formation is held inside the hook 2, below the hook tip 4. The latch 6, shown in its rearward position 8, also plays a role in loop formation. In this position, the latch tip 12 reaches a point at which it is oriented maximally toward the needle butt 5 in the longitudinal direction z (also referred to as the drive section 33). The latch 6 pivots to the needle bar 3 at the pivot point 14. The needle bar 3 has a predetermined breaking section 9, which has a notch or recess, at which the height of the needle bar or the dimension of the needle bar in the height direction x decreases from above. The shape of the relevant recess is triangular and has a rounded tip. In the rounded tip, the triangle encloses an angle of 90° ("aperture angle"). At the point of the smallest remaining cross-sectional area, the height of the needle bar 3 is reduced by about 50%.

FIG. 3 corresponds essentially to FIG. 2 , except that it shows an alternative embodiment of the predetermined breaking section 9 . The cross-sectional area is reduced less than in the embodiment of FIG. 2 . The rounding of the tip of the recess formed in the predetermined breaking section is absent or too small to be discernible in this figure. In each embodiment, the tip of the recess formed may be rounded. In all embodiments, the corners formed on the upper edge of the needle bar 3 on the left and right sides of the predetermined breaking section 9 may also be rounded.

FIG. 4 shows an overall view of another embodiment of a knitting machine needle 1. Apart from the alternative configuration of the predetermined breaking section 9, the knitting machine needle 1 corresponds largely to the knitting machine needle 1 of FIG. 1 . In addition, a first transition point 28 and a second transition point are indicated by large brackets, as well as a fourth section 30 of the needle bar 3 and a fifth section 31 of the needle bar 3. The height of the needle bar 3 (dimension in the height direction x) is at a maximum from the needle butt 5 to the first transition point 28. After the first transition point 28, the height of the needle bar 3 decreases rapidly to a medium height towards the hook 2 of the needle bar 3. After the second transition point 29, the height of the needle bar 3 decreases again towards the hook 2. The fourth section 30 of the needle bar 3 extends in the longitudinal direction z of the knitting machine needle 1 from the pivot point 14 of the needle tongue 6 to the second transition point 29. The fifth section 31 of the needle bar 3 extends in the longitudinal direction z of the knitting machine needle 1 from the tip 12 of the needle tongue 6 in its rearward position 8 to the second transition point 29. The minimum height of the needle bar 3 and thus the appropriate position of the predetermined breaking point 9 can be determined in two sections. The height of the needle bar in the needle bar section between the second transition point 29 and the first drive section 33 is greater, so that this needle bar section does not provide an optimal position for the predetermined breaking section 9.

The predetermined break point 9 can be more easily identified in the enlarged view of Figure 5. The knitting machine needle 1 in Figure 5 differs essentially from the knitting machine needle 1 in Figures 2 and 3 only in the structure of the predetermined break section 9. The predetermined break section 9 is formed by reducing the height of the needle bar 3 from below in the height direction x. In all other aspects, this reduction "from below" has exactly the same structure as the reduction "from above" shown in Figure 2. In all embodiments of the knitting machine needle 1, the reduction in the needle bar diameter can always be advantageously performed from above, from below, or from above and below. Alternatively or in combination, a reduction in the width direction y is also available. FIG. 5 additionally shows the transverse flank 25, the reduced height shape 26 in the needle shaft height dimension in the z-x plane, and the reduced height aperture angle 27.

FIG. 6 shows an enlarged view of the front region of a knitting machine needle 1 which corresponds substantially to the knitting machine needle 1 shown in FIGS. 1 to 5 , except for the way in which the predetermined breaking section 9 is realized. In this embodiment, the predetermined breaking section 9 is formed by a section of the needle bar 3 whose cross section has not been adjusted to form the predetermined breaking section 9. Alternatively, as represented by the hatching of the needle bar 3 in the predetermined breaking section 9, the material of the predetermined breaking section 9 has improved properties and, in particular, has a smaller elongation at break than the adjacent sections 23, 24 of the needle bar 3. Such an adjustment of the material properties in the predetermined fracture zone 9 can be advantageously used in all embodiments of the invention as an alternative to or in combination with other measures such as a reduction in the cross-section.

FIG. 7 corresponds essentially to FIG. 2 . For the sake of clarity, the needle latch 6 of the knitting machine needle 1 of FIG. 7 is shown in both of its two end positions. The needle latch is shown both in its closed position 7 and in its rearward position 8 . The sections 23 , 24 adjacent to the predetermined breaking section are also shown.

Furthermore, in FIG. 7 , the cross-sectional lines A-A and B-B are shown at two locations on the needle bar 3. The associated sectional views are arranged on the right side of the knitting machine needle 1 in FIG. 7 and show, for one of them, an unreduced cross-sectional view 22 of the needle bar and, for the other, a reduced cross-sectional view 21 of the needle bar. The sectional views show in the background the first needle butt 5, the first transition point 28, and the second transition point 29.

FIG. 8 shows a cross section through a groove of a needle bed 16 of a knitting system 15 according to the invention. The cutting line here is immediately in front of (and parallel to) the side wall of the knitting needle 1 in the width direction. The knitting system 15 is similar to the knitting systems described in the publications DE 33 11 361 A1 and DE 10 2014 118 217 A1. The figures are not drawn to scale and have omitted components which are essential for the knitting process - for example further knitting tools (in particular sinkers). As previously described, the omitted sinkers guide the knitting needle 1 in its width direction y in sections which are located in front of the groove wall 17 in the longitudinal direction z of the knitting needle 1. Therefore, the sinker adjacent to the knitting needle 1 will usually be partially visible behind the knitting needle 1. The knitting machine needle 1 is guided in two dimensions by means of the guide means 17 of the needle bed 16. In the height direction x, the knitting machine needle 1 is supported by the bottom of the groove 32 of the needle bed 16. The knitting machine needle 1 is guided in the width direction y by means of two groove walls 17. In the accompanying figure of FIG. 8 , only one groove wall 17 of the needle bed 16 is shown, which guides the rearward part of the knitting machine needle 1 in which the butt 5 is located in the width direction y (as mentioned above, the sinker which replaces the guiding function in front of the groove has been omitted). The butt 5 of the knitting machine needle 1 is engaged in the cam element 18 shown in section. Towards the front of the knitting machine needle 1 in its shown position in the needle bed 16, in particular from the hook 2 to the predetermined break section 9, the knitting machine needle 1 is not supported in the height direction x by the needle bed 16. This state occurs at least in those cases according to the knitting system 15 of the invention during the knitting operation when the knitting machine needle 1 is raised to the maximum extent. When the knitting needle 1 is in the raised position, in particular a predetermined break can occur, in which the needle bed 16 or other knitting machine parts no longer ensure a forward supporting function for the predetermined break section 9 or at least for a large part of the hook end portion of the knitting needle. This applies even more here, since in the loading position shown, the predetermined break caused by the force F most likely occurs by a snapping break of the front part of the needle 1 with the hook 2. This snapping break is facilitated by the length of the lever (here the distance from the hook 2 to the predetermined break section 9) (lever action).

1: Knitting machine needles

2: Bend hook

5: Pin heel

9: Predetermined breaking section of needle tongue 6

15: Knitting system

16: Needle bed

17: Guiding mechanism

18: Cam element

32: Bottom of groove 32 of needle bed 16

F: Strength

x: height direction

y: width direction

z: longitudinal direction

Claims (14)

A knitting machine needle (1) comprises: a hook (2) for forming a yarn loop, the hook limiting the needle bar (3) in the longitudinal direction (z) of the needle bar (3) and terminating at the hook tip (4); a first drive section (33) following the hook (2) in the longitudinal direction (z) of the needle bar (3); and a predetermined breaking section (9). Used to separate the hook (2) from the first drive section (33); it is formed by a section of the needle bar (3) extending in the longitudinal direction (z); and it is completely located in the first needle bar section (10) and extends in the longitudinal direction (z) of the needle bar (3) between the tip (4) of the hook (2) and the first drive section (33). A knitting machine needle (1) as claimed in claim 1, wherein the predetermined breaking section (9) breaks under a force applied to the hook (2) and less than 80% of the force; under the action of the force, a knitting machine needle with the same structure but without the predetermined breaking section (9) becomes permanently deformed. A knitting machine needle (1) as claimed in claim 1 or 2, further comprising a needle latch (6) pivoted to the needle bar (3) in such a manner that in its closed position (7), the needle latch (6) closes the interior of the hook (2), and when the needle latch (6) is in its rearward position (8), the tip of the needle latch points in the longitudinal direction (z) of the needle bar (3) towards the first drive section (33). A knitting machine needle (1) as claimed in claim 3, wherein the predetermined breaking section (9) is completely located in the second needle bar section (11); wherein the second needle bar section (11) extends in the longitudinal direction (z) of the needle bar between the position of the needle latch tip (12) in the backward position of the needle latch (6) and the hook side starting point (19) of the first drive section (33). A knitting machine needle (1) as claimed in claim 4, wherein the predetermined breaking section (9) is completely located in the third needle bar section (13); it starts from a point separated by two needle latch lengths from the pivot point (14) of the needle latch (6) in the direction of the first drive section (33) in the longitudinal direction (z) of the knitting machine needle (1); and it ends at a point separated by three needle latch lengths from the pivot point (14) of the needle latch (6) in the direction of the first drive section (33) in the longitudinal direction (z) of the knitting machine needle (1); wherein the needle latch length is the distance between the pivot point (14) of the needle latch and the tip (12) of the needle latch. A knitting machine needle (1) as claimed in claim 5, wherein the hook side starting point (19) of the first driving section (33) in the longitudinal direction (z) is spaced at least 75 mm from the hook side starting point (20) of the knitting needle (1) in the longitudinal direction (z) of the needle bar (3). A knitting machine needle (1) as claimed in claim 6, wherein the drive section (33) is formed by a needle butt (5), and the needle butt (5) protrudes above the needle bar (3) in the positive height direction (x) of the needle bar (3). A knitting machine needle (1) as claimed in claim 7, wherein the predetermined breaking section (9) comprises a reduced portion (21) in the cross section of the needle bar at right angles to the longitudinal direction (z). A knitting machine needle (1) as claimed in claim 8, wherein the predetermined breaking section (9) includes a reduced portion (21) in the needle bar cross section (22) due to a reduction in the needle bar size in the height direction (x). A knitting machine needle (1) as claimed in claim 9, wherein at the point on the predetermined break section (9) having the maximum reduction (21) in the needle bar cross section (22), the predetermined break section (9) has a reduction in the needle bar dimension in the height direction (x) of at least 10% and at most 50%. A knitting machine needle (1) as claimed in claim 10, wherein the reduction of the needle bar size in the height direction (x) is carried out in a process, which has a triangular or trapezoidal shape (26) in the plane defined by the height direction (x) and the longitudinal direction (z), and the transverse sides (25) of the shape (26) mutually enclose an aperture angle of 60° to 120°. A knitting machine needle (1) as claimed in claim 11, wherein the predetermined breaking section (9) at least partially comprises a material having a smaller breaking elongation than the remaining sections (10, 11, 13) of the needle bar (3), and in particular smaller than the sections (23, 24) of the needle bar (3), the sections (23, 24) being adjacent to the predetermined breaking section (9). A knitting system (15) comprises at least: a needle bed (16) with a guide member (17) and at least one groove bottom (32) which is arranged to receive a knitting machine needle (1) and to support and guide the knitting needle in its longitudinal direction (z) during its intermittent movement; at least one cam element (18) for transmitting force to at least one first drive section (33) of the knitting machine needle (1) located in the needle bed (16); a plurality of knitting machine needles (1), wherein each of these knitting machine needles (1) comprises the following features for its part: a hook (2) for forming a yarn loop, which limits the needle in the longitudinal direction (z) of the needle bar (3); The invention relates to a knitting machine needle (1) having a first drive section (33) which is located behind the hook (2) in the longitudinal direction (z) of the needle bar (3) and terminates in the hook tip (4); the first drive section (33) is characterized in that at least one of the knitting machine needles (1) has a predetermined breaking section (9) for separating the hook (2) from the first drive section (33); It is formed by a first needle bar section (10) extending in the longitudinal direction (z) of the needle bar (3); and it is completely located in the first needle bar section (10) and extends in the longitudinal direction (z) of the needle bar (3) between the tip of the bend (2) and the bend side starting point (19) of the first drive section (33). A knitting system (15) as claimed in claim 13, wherein the guide member (17) of the needle bed (16), the at least one groove bottom (32), the at least one cam element (18), and the position of the drive section (33) on the at least one knitting machine needle (1) and the position of the predetermined break section (9) are set in the following manner: during knitting, the at least one knitting machine needle (1) is at least intermittently raised to a position away from the guide member (17) and the at least one groove bottom (32); the guide member (17) and the at least one groove bottom (32) at least intermittently no longer support the predetermined break section (9) of the at least one knitting machine needle (1).

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