EP1870502B1 - Latch needle for loop forming textile machine - Google Patents

Description

The invention relates to a latch needle for a stitch-forming machine, in particular for a knitting machine for producing textile surfaces.

To form stitches, so-called latch needles are used in machines, in particular in knitting machines, which are moved back and forth to form the stitches in rapid succession. The tongue provided on a knitting machine needle opens and closes a receiving space for a thread in rapid succession and at high speed. This receiving space is bounded by the needle body and at its one end hook in cooperation with the opening and closing tongue. The tongue beats alternately on the hook in rapid succession, forming the closed position, as well as on the shaft of the latch needle, to form the open position or reserve. In the stitch formation process, the tongue of the latch needle is moved through the loop or half stitch. The tongue speed is highest at the tip of the tongue and decreases with the distance to the pivot point of the tongue on which it is mounted in the knitting machine needle. The kinetic energy of the tongue head must be destroyed on impact in the closed position on the hook and in the open position on the needle shaft. For this purpose, a state-of-the-art knitting machine needle 1 follows FIG. 4 . 4a . 5a and FIG. 7 on the top 37 of its needle body 2 a trough-like recess 27 and a receiving hopper 15 in the form of an impression. This follows in cross-section substantially a circular arc and is adapted to the back surface 23 of the tongue head 8, which is held by a tongue shaft 9. The tongue shaft 9 merges on both sides on a line 24 in the tongue head 8, which forms the edge of a facet 10, 10 '. The surfaces or facets 10, 10 'are at an acute angle to each other and connect to the back surface 23 at. The tongue head 9 is symmetrical to the central axis B and has, on its side facing the needle body, a width which, with the relatively large width C + of the recess (FIG. FIG. 4a ) matches.

This relatively large width C + of the receiving hopper 15 and also the large mass of the tongue head can cause problems because this mass must be moved at high speed between the closing and backing back and forth. The kinetic energy must be destroyed at the receiving hopper 15 for the tongue head. In the open position, this is done by the spring action of the bearing areas of the sheep cheeks, which are also referred to as jaws of the latch needle. This spring action can be achieved by extending the tongue slot or be influenced by an additional, second slot in the latch needle.

The forces generated by the impact of the tongue in reserve can be so great that the jaws or tongues break.

Another load, which is exposed to a machine knitting needle during the stitch formation, is caused by tensile forces of the knitted fabric. The machine knitting needle is guided in a needle channel of a needle bed and rests with the bottom of the needle (needle back) on the bottom of the needle channel. This can end in the throat area, ie the area of the receiving funnel of the latch needle. During the stitching operation, the needle moves well beyond the support area of the needle carrier. In this area, the machine knitting needle is subjected to tensile forces acting in the direction of the needle carrier. These tensile forces are caused by the fabric removal. The fabric withdrawal pulls already knitted goods away from the needles. The goods are held by the needles through half-stitches, which are located on the back of the needle. As a result, the pull-off forces on the half-stitches act directly on the needle body, which undergoes its support in the needle carrier. Now, if the half-stitches are cut off over the closed tongues, these tensile forces increase, the farther the half-stitches move in the direction of the needle hook. The resulting stresses can lead to Nadelschaftbrüchen. The needles usually break at the receiving hopper or shaping impression, which forms a weak point of the latch needle body and lies approximately at the end of the needle carrier (the so-called knock-off edge) when the knitting machine needle is in the extended position. An on a tongue head according to the prior art adapted form impression, which has a corresponding size, promotes this breaking behavior.

From the DE-OS 28 17 136 a tongue needle is known, the needle shaft has a recess, wherein the shape of the recess is formed complementary to the back surface of the tongue head. The recess is formed by removing needle shank material. The contact surface of the tongue head is limited to the existing width of the side walls of the needle shaft, ie the needle shank cheeks, wherein the needle shaft is weakened by the removal of material for the production of the recess. This increases the susceptibility to breakage of the latch needle.

From the DE-OS 22 25 835 It is known to reinforce the tongue head with a lateral rib in order to counteract the wear occurring in the stitch formation process and the susceptibility to breakage of the tongue head. This measure leads to an increase in the mass of the tongue head and has not prevailed in practice.

From the U.S. Patent 2,817,222 It is known to provide the back of the tongue head with a projecting rib which dips into the tongue slot in the open position of the tongue. With this measure, tongue and jaw fractures should be avoided. From the EP 1 584 722 A is known to form a rib of tongue head by this is provided with recesses.

From the DE-PS 27 14 607 It is known to damp the impact of the needle tongue in the open position or reserve by a special design of the needle longitudinal slot and thereby otherwise occurring in the reserve of the needle tongue damage to the tongue and the needle itself to avoid. This is followed by the first needle longitudinal slot, the the tongue receives, a second needle longitudinal slot, which projects beyond the end of the open tongue with its length. By this measure, the elasticity of the needle shank cheeks is increased. However, this measure is not sufficient to meet today's requirements for high-speed knitting machine needles.

On this basis, it is an object of the invention to provide a latch needle for a stitch-forming machine, said latch needle to show a reduced tendency to needle or tongue fractures.

The latch needle according to the invention according to claim 1 meets these expectations. It has at its tongue back at least two first facets, which are arranged divergent as in a conventional latch needle in the tongue longitudinal direction. In addition, two further (second) facets are provided, which are arranged between the existing facets and the back of the tongue. They diverge from the back of the tongue. As a result, the facets are arranged inclined to a plane imaginary by the central axis. The opening direction of the preferably acute angle enclosed by the first facets substantially coincides with the tongue longitudinal direction. The opening direction of the preferably acute angle enclosed by the second facets substantially coincides with a direction which deviates from the tongue longitudinal direction and lies in the median plane. The first two facets are preferably arranged symmetrically to the median plane. The two second facets are preferably also arranged symmetrically to the median plane. These facets can be flat or arched. In this case, a concave curvature is preferred. The facets are at the end of the spoon-shaped Tongue head, arranged at which this connects to the tongue shaft. The tongue shaft has a width which is slightly smaller than the width of the tongue slot, so that the tongue is kept movable in the tongue slot. The tongue head projects beyond the tongue slot and also the hook of the latch needle in its width, in order to ensure the knocking off of the half stitch over the tongue head smoothly.

The second facets lead to a weight reduction of the tongue head, which reduces its kinetic energy. In addition, the pressure to be provided on the needle body shape impression can be made narrower than before, which reduces the otherwise existing weakening of the needle body at this point.

The first two facets form a transition section from the relatively narrow tongue shaft to the broad tongue head. This transition section may partially dive into the tongue slot and / or in the receiving hopper of the needle body. In this case, this transition section of the tongue preferably has on each side in each case a first and a second facet. Starting from the flat side of the tongue shaft whose width is first increased by the first, each other a wedge-forming facets until the maximum width of the tongue head is reached. The second, preferably elongated, facet is adjacent to the preferably substantially triangular first facet, thereby reducing the cross-section of the latch head in the transition section of the latch shaft to the latch head. The transition portion of the tongue shaft is in the region of the receiving hopper, which can thus be reduced in size, in particular its width. The second facet is at an obtuse angle arranged to the first facet. Both facets can merge seamlessly into one another, so that the sliding of the stitches over the back of the tongue is not hindered. The transition of the two molding surfaces into each other can be designed, eg rounded, that it is not possible to determine an exact boundary of the two molding surfaces. In addition, the facets with rounded edges and edges in the other tongue back can go over.

Due to the second shaping surface, the cross section or the volume of the tongue head is reduced at the section with which the tongue head dips into the receiving funnel of the sheep cheeks in open position or touches it. As a result, the width of the receiving hopper can be reduced. As a result, the needle shank cheek can be formed wider at its top. This leads to a reinforcement of this critical area of the needle body, which otherwise forms a weak point.

The shape of the receiving hopper, ie the so-called shaping impression, can be adapted to the back of the tongue head. The shape corresponds to the shape of the tongue head in the region in which the tongue head rests against surfaces of the shaping impression. The tongue head usually has a curved shape that follows a radius. Where the receiving hopper merges into the upper side of the sheep cheeks, it can have at least one partial surface. This partial surface is preferably aligned parallel to the second facet of the tongue head. A section through the receiving hopper is then bounded by a curve consisting of an arcuate portion and two straight line sections. It is thus possible a receiving hopper for the tongue head, at its lowest point in the center of a bow, such as a circular arc follows, ie is curved and is formed at its ends areal. This receiving hopper can be adapted substantially to the shape of the tongue head in this area.

Further details of advantageous embodiments of the invention will become apparent from the drawing, the description and / or the claims.

Figur 1

eine zungengezaschte Nadel mit verbessertem Übergangsbereich zwischen Zungenschaft und Zungenkopf in schematisierter, ausschnittsweiser Seitenansicht in Schließ- und Rücklage der Zunge,

Figur 2

die Zungennadel nach Figur 1 in einer schematisierten Seitenansicht mit Zunge in Rücklage und in einem anderen Maßstab,

Figur 3

die Zunge nach Figur 2, geschnitten entlang der Linie A-A in einem anderen Maßstab,

Figur 3a

eine vergrößerte Darstellung des Aufnahmebereichs einer Zungenadel nach Figur 3

Figur 4

einen Schnitt entsprechend Figur 3 einer Zungennadel gemäß des Standes der Technik,

Figur 4a

eine vergrößerte Darstellung des Aufnahmebereichs einer Zungenadel gemäß des Standes der Technik nach Figur 4,

Figur 5

die Zunge der zungengezaschte Zungennadel nach Figur 1 in einer ausschnittsweisen Seitenansicht in einem anderen Maßstab,

Figur 5a

die Zunge der Zungennadel nach dem Stand der Technik in einer ausschnittsweisen Seitenansicht,

Figur 6

die Draufsicht des Formeindrucks gemäß der Zungennadel nach Figur 1 und

Figur 7

die Draufsicht eines Formeindrucks einer Nadel nach dem Stand der Technik im vergrößerten Maßstab.

Exemplary embodiments of the invention are illustrated in the drawings. Show it:

FIG. 1

a tongue-stained needle with improved transition region between the tongue shaft and the tongue head in a schematic, fragmentary side view in the closing and backing of the tongue,

FIG. 2

the latch needle after FIG. 1 in a schematic side view with tongue in reserve and on a different scale,

FIG. 3

the tongue after FIG. 2 cut along the line AA on a different scale,

FIG. 3a

an enlarged view of the receiving area of a tongue needle after FIG. 3

FIG. 4

a cut accordingly FIG. 3 a latch needle according to the prior art,

FIG. 4a

an enlarged view of the receiving area of a tongue needle according to the prior art after FIG. 4 .

FIG. 5

the tongue of the tongue-struck tongue-needle follows FIG. 1 in a fragmentary side view on a different scale,

FIG. 5a

the tongue of the latch needle according to the prior art in a fragmentary side view,

FIG. 6

the top view of the shape impression according to the latch needle FIG. 1 and

FIG. 7

the plan view of a shape impression of a needle according to the prior art on an enlarged scale.

In FIG. 1 a latch needle 1 is illustrated, which has a needle body 2 with a stitch-forming part 3, on which end a hook 4 is formed. The hook 4 is provided with a tip 12 which may be rounded at its upper side 18.

The needle body 2 has at its stitch-forming part 3 a tongue slot 17 into which a tongue 6 projects with one end 19. The tongue 6 is held in the tongue slot 17 on a bearing device 5 and pivotally mounted. The storage device 5 is z. B. formed by a tongue slot 17 by cross-bearing axis. This bearing axis may be formed in the form of a bearing pin or preferably in the form of a one-piece or multi-part with the needle body 2 seamlessly connected pin. To this storage device 5 is the tongue 6 of the in FIG. 1 Closing position illustrated on the left side pivotally mounted in a reserve, the in FIG. 1 is illustrated on the right.

The tongue has a narrow, preferably parallelflankig limited shaft 9, the width of which is slightly smaller than that of the tongue slot 17. The length of the tongue 6 is dimensioned so that it can reach the top 18 of the hook 4 with its end 20 and partially overlaps , The end 20 is provided on the hook 4 side facing with a recess 21, according to the embodiment according to FIG. 1 a trough 22 for receiving at least a portion of the hook 4 forms. The trough 22 may correspond to the shape of the top 18 of the hook 4 and be adapted.

The latch needle 1, in particular the needle body 2, is held movably in a needle carrier 36. The needle carrier 36 may end approximately at the axial position, where the tongue head 8 cooperates in reserve with the needle body 2. The needle body 2 is supported at this point by the needle carrier 36, in particular when the needle is subjected to the tensile forces F of the fabric take-off.

The formation of the end 20 of the tongue 6 is further from the Figures 2 . 3 and 5 out. At the end 20 includes a back surface 23, which forms the back of a end formed on the tongue 6 spoon. The tip of the spoon marks the end 20 of the tongue 6. Its width exceeds the width of the substantially parallel-flanked tongue shaft 9. The tongue shaft 9, whose width is determined by the distance of its flat sides 7 and 7 'from each other, goes to a line 24 with the Transition region 16 in the tongue head 8 via. The width of the tongue head 8, which is measured perpendicular to the flat sides 7, 7 ', increases continuously from the line 24 in the axial or tongue longitudinal direction progressively. Their maximum distance reaches them at the in FIG. 2 and 5 dashed line 25, which cuts the spoon. The (imaginary) line 25 is located approximately in the middle of the tongue head length L, which extends from the line 24 to the end 20 of the reed head 8. The widest point of the tongue head 8 may also be displaced in the direction of the line 24 so that it does not lie in the middle of the tongue head length L.

The increase in the width of the tongue head 8 is (as in FIG. 2 ) determined by the first facet 10. The edge of the facet 10 is preferably an isosceles triangle. The facet 10 is preferably flat. It is also possible to make them convex or concave curved.

Subsequent to the facet 10, a second facet 11 is formed on the tongue head 8. This facet 11 lies above the receiving hopper 15 of the needle body 2 when the tongue 6 is in reserve. This second facet 11 is an elongated molding surface which, as seen in FIG FIG. 3 can be seen, is arranged at an obtuse angle α to the first facet 10. The length of the facet 11 to be measured in the longitudinal direction of the tongue may extend as far as the line 25 or, if appropriate, slightly beyond (FIG. FIG. 2 ). Embodiments are also possible in which the facet 11 extends almost over the entire length of the tongue head. It then extends, starting from the forming surface 10, to the end 20 of the tongue head 8 and then ends at the trough 22, which is close to the tongue head end.

FIG. 3 1 shows an exemplary embodiment in which the tongue head 8 has two first diverging facets 10, 10 ', which intersect the drawing plane oriented transversely to the longitudinal direction of the needle in a line which is parallel to a plane B, which in turn is parallel to the flat sides 7, 7'. the tongue shaft 9 is arranged. Subsequent to the first facets 10, 10 ', the tongue head 8 has on each side of the plane B in each case a second planar facet 11, 11'. The two facets 11, 11 'enclose an acute angle β with one another. As a result, the cross-sectional area and the volume of the tongue head 8 are reduced in the transition region 16, with which it cooperates with the receiving hopper 15 or in which it rests in the receiving hopper 15. The arrangement of the facet 11 is selected such that an extension beyond the back surface 23 in the direction of Needle body 2 the tongue slot 17 cuts. Tangents of the facets 11, 11 ', which are applied to the facets in the plane of the drawing, form an intersection point A. This intersection point A preferably lies on the center plane B and varies as a function of the angle β. The distance between the intersection A and the back 23 of the needle tongue 6 is preferably at least half the thickness of the tongue shaft 9.

The receiving hopper 15 is formed by a recess 27 which is adapted to the back surface 23 in the transition region 16 of the reed head 8. In this case, the receiving hopper 15 at its lowest point in the vicinity of the median plane B has a curvature which substantially corresponds to the curvature of the adjacent portion of the back surface 23 of the reed head 8. In the edge region 28, 28 'of the receiving hopper 15, this has two partial surfaces 29, 29', which are formed substantially parallel to the second facets 11, 11 '. The receiving hopper 15 has, measured transversely to the center plane B, a width C ( FIG. 3a ), which is substantially smaller than in a receiving hopper according to the prior art ( FIGS. 4 . 4a and 7 ). The width of the upper sides 32, 32 'of the needle shaft cheeks 30, 30' adjoining the receiving hopper 15 is determined by the size of the chamfer 31, 31 'and the width C of the receiving hopper 15. This width of the upper side 32, 32 'is compared to the width of a top side 32 of a needle according to the prior art ( FIG. 4 . 4a and 7 ) significantly larger, at least 1.5 times as large. This increases the stability of the sheep cheeks 30, 30 'in this area and thus the stability of the needle body 2 as a whole.

The receiving hopper 15 is produced by a non-cutting machining. Thus, material from the region of the needle shaft cheek 30, 30 'in the direction of the tongue slot 17 be relocated. As a result, a support surface is created in the receiving hopper 15 above the tongue slot 17. The material displacement can be carried out in such a way that the edges of the projections formed on the sheep cheeks 30, 30 'almost touch each other in the area of the center plane B ( FIG. 6 ).

FIG. 3a shows the width C of the receiving hopper 15. Between the top 32 and the receiving hopper 15 is a boundary D. Between the top 32 'and the receiving hopper 15 is a limit D'. The width C of the receiving hopper 15 is to be measured from the boundary D to the boundary D '. The width C of the receiving hopper 15 is substantially lower than in the case of a needle according to the prior art ( FIG. 4 . 4a and 7 ). This is achieved by the arrangement of the partial surface 29, 29 'in the recess 27. The rounding of the receiving hopper 15, which corresponds to the rounding of the back surface 23 of the tongue head 8 in a needle according to the prior art, is interrupted by the partial surfaces 29, 29 '. FIG. 3a shows by way of example on the right needle shaft cheek 30 in dashed lines the imaginary extension of the otherwise uniformly rounded surface of the receiving hopper 15. Due to deviating from the other rounding faces 29, 29 ', the width C of the receiving hopper 15 in comparison to conventional form impressions by two times the Track X be scaled down. The distance X is the distance between the boundary D and the end of the receiving hopper 15 without partial surfaces 29, 29 'according to the prior art. By reducing the width C of the receiving hopper 15, the widths of the upper sides 32, 32 'of the needle shank cheeks 30, 30' can be increased by the amount X.

Due to the arrangement of the facets 11, 11 '( FIG. 3 ), the cross-sectional area, and the volume of the reed head 8 are significantly reduced. A comparison of FIG. 3 a needle according to the invention, with the FIG. 4 A prior art needle makes this reduction in volume or cross-sectional area clear.

How out FIG. 5 can be seen, a transition 33 is formed between the facet 10 and the facet 11 of the tongue head 8. This transition 33 may be formed as a rounded or smoothed edge, which does not hinder the stitch formation. The transition 33 may also be formed as a surface or other facet. This serves the smooth transition of the facet 10 into the facet 11. A clear boundary between the facets 10 and 11 is then no longer discernible.

Furthermore, it is off FIG. 5 an alternative embodiment of the facet 11 in dashed lines visible. This alternative facet 11 extends from the facet 10 almost over the entire length of the reed head 8 and follows its lateral curvature. In the design of the facet 11, requirements of the stitch forming process may be taken into account.

FIG. 6 shows a plan view of the recess 27 of the receiving hopper 15. This can be formed by a forming process from the sheep cheeks 30, 30 'out and two curved surfaces 34, 34' have. The edge of the surface 34 is preferably rounded at the side facing the chamfer 31. This increases the stability of the knitting machine needles in this area compared to prior art knitting needles and FIG. 7 considerably. The same applies mutually to the forming surface 34 '. The danger the formation of an undesirable weak point due to a corner in the edge of the surface 34, 34 'and the recess 27 (FIG. Fig. 7 ) is thus significantly reduced.

The tongue needle 1 described so far works as follows:

In operation, the latch needle 1 according to their in FIG. 1 reciprocated by an arrow 35 longitudinal direction. The tongue oscillates continuously between the closed position ( FIG. 1 left side) and the reserve ( FIG. 1 right side). In the closed position, the recess 21 partially overlaps the hook 4. In the reserve, however, the hook 4 is released. When swinging back and forth wins the tongue 6 respectively kinetic energy that leads to a shock load of the hook 4 and the tongue 6 when hitting the reserve or when hitting the hook 4. The facets 11, 11 'reduce in comparison to a tongue 6 of the same shape, but without such surfaces, the volume of the tongue head 8 and thus the reacted kinetic energy handsomely. In addition, the latch needle 1 is reinforced due to the adapted, narrowed shape of the receiving hopper 15 and can better absorb and absorb the kinetic energy. This results in a lower load on the top 18 of the hook 4 and in the region of the recess 27 in reserve of the latch needle 1. This leads to the reduction of the shock acting on the tongue 6 and the needle body 2, which the number of breaks in Area of the tongue shaft 9 and the needle body 2 reduced.

The latch needle 1 according to the invention has a tongue 6, which on its tongue spoon on the side facing away from the hook 4 thereof with at least two facets or forming surfaces 10, 11 is provided. These facets 11, 11 'converging towards the tongue back 23 reduce the volume of the tongue head 8. This makes it possible to reduce the width C of the recess 27, resulting in stabilization of the knitting needle 1 in this area.

LIST OF REFERENCE NUMBERS

1

latch needle

2

needle body

3

stitch forming part

4

hook

5

Storage facility

6

tongue

7, 7 '

flat side

8th

latch head

9

latch shaft

10, 10 ', 11, 11'

Form surfaces / facets

12

top

15

receiving hopper

16

Transition area

17

latch slot

18, 37

top

19, 20

The End

21

deepening

22

trough

23

backrest

24, 25

line

26

needle back

27

recess

28, 28 '

border area

29, 29 '

subarea

30, 30 '

Needle shank cheeks

31, 31 '

chamfer

32, 32 '

top

33

crossing

34, 34 '

area

35

arrow

36

needle carrier

A intersection B midplane C, C + width D, D ' The End F off force L Latch head length X route α angle β angle

Claims (10)

1. Latch needle (1) for a stitch-forming textile machine, in particular knitting machine,

   with a needle body (2), which has a stitch-forming part (3) with a hook (4), a sawslot (17), a bearing means (5) arranged in the sawslot (17) and a receiving cone (15),

   with a latch (6) having a latch blade (9), which is disposed to pivot on the bearing means (5) and bears a latch head (8) having a transition area (16) with sides pointing away from one another, in which area the latch blade (9) merges into the latch head (8),

   respectively with a first bevel (10, 10') arranged on each side of the transition area (16) of the latch head (8),
   wherein the latch (6) is disposed to pivot between a closed position, in which it touches the hook (4), and a shift position, in which its latch head (8) cooperates with the receiving cone (15),
   characterised in that
   at least one further bevel (11), which adjoins the first bevel (10), is configured on the transition area (16) of the latch head (8).
2. Latch needle according to claim 1, characterised in that the bevel (10) merges into a broad flat side (7, 7') of the latch blade (9).
3. Latch needle according to claim 2, characterised in that the bevel (10) is a plane surface arranged at an obtuse angle to a flat side (7, 7') of the latch blade (9).
4. Latch needle according to claim 1, characterised in that the bevels (10, 11) merge into one another.
5. Latch needle according to claim 1, characterised in that the cross-section of the latch head (8) in the transition area (16) is delimited by at least two bevels (10, 11) and a rear face (23).
6. Latch needle according to claim 5, characterised in that the cross-section of the latch head (8) in the transition area (16) is delimited by at least four bevels (10, 10', 11, 11') and the rear face (23).
7. Latch needle according to claim 6, characterised in that a first bevel is respectively configured on each side of the latch (6), so that the two first bevels (10, 10') intersect a transverse plane at lines parallel to one another.
8. Latch needle according to claim 1, characterised in that the first bevel (10) forms an obtuse angle (α) with the second bevel (11).
9. Latch needle according to claim 1, characterised in that the at least one second bevel (11) is arranged on the latch head (8) in such a way that a tangent placed against the bevel (11) intersects the sawslot (17) when the latch head (8) is received by the cone (15).
10. Latch needle according to claim 1, characterised in that the second bevels (11) are arranged on the latch head (8) in such a way that tangents placed against the bevel (11) and pointing into the sawslot (17) enclose an acute angle (β) with one another.

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