EP2009160B1 - Cutting needle with replaceable blade - Google Patents

Description

For knitting machines, for example, cutting needles are made using cutting needles having a needle body with a hook provided at one end and a blade portion formed adjacent to the hook. The knife portion has a sharpened cutting edge, which serves for slicing stitches. If the knife section is dulled by prolonged use, the quality of the knitwear suffers. The cutting needle must then be replaced.

From the DE 21 26 522 a cutting needle with a needle body is known, at the end a hook is formed. The needle body is provided with a slot for receiving a knife. The knife is held interchangeable on the needle. Further describes the EP 1 710 335 A2 a cutting needle according to the preamble of claim 1.

On this basis, it is an object of the invention to provide an improved cutting needle.

This object is achieved with the cutting needle according to claim 1.

The cutting needle according to the invention has a needle body and a knife, which is detachably connected to the needle body. By this measure, the knife can wear replaced and replaced with a new sharpened knife. It is also possible to remove a worn knife from the cutting needle and sharpen separately.

The cutting needle may remain in the knitting machine when the knife is to be replaced. It is not necessary to open the knitting machine lock. This greatly facilitates the maintenance of the knitting machine with truncated cutting edges of the cutting needles.

Preferably, a seat for receiving and supporting the knife is provided on the cutting needle. This seat may for example be in the form of a slot extending through the needle body. The slot is preferably located in the needle body longitudinal direction adjacent to the hook. Between the slot flanks the knife is held. It sits in the slot, preferably with very little lateral play, so that it is precisely captured. The slot is preferably arranged centrally in the needle body. It is then bounded laterally by webs or slot walls. The slot walls are part of the needle body and preferably formed parallelflankig. The slot width and the cross section of the slot walls can be approximately the same size. They are preferably each one third of the needle thickness in the slot area. Depending on the field of application, however, the thickness ratios can vary. For example, when using a large diameter cutting blade, the slot width may be greater than one third of the needle thickness in the slot area. The slot width can take up half of the needle thickness and in some cases even larger. When using a very fine cutting blade, the slot width can be very small, it can then take, for example, only 20% of the needle thickness in the slot area or even less.

The knife socket formed by the slot preferably contains at least one form-locking holding means for supporting the knife. This form-locking holding means is engaged with the knife to store it at least at one of its ends or in an area near the end. The form-locking holding means is, for example, a first projection protruding into the slot, which is received by a recess of the knife. The recess may be in the form of an opening which adjoins both flat sides of the knife and thus passes through the knife, or be formed on the front side, the hook-facing end of the knife. These positive locking means may form a pivoting hinge, which supports the knife at its front, hook-side end.

Furthermore, a moment supporting surface for the knife can be provided on the needle body. This is preferably arranged on the distal end of the form-locking holding means of the slot. It serves to absorb and support a pressure force exerted by the thread, in particular when the cutting edge gradually blunts, on the knife. The moment supporting surface is preferably a preferably flat surface extending in the longitudinal direction of the needle body. This surface is preferably oriented approximately radially to the pivot axis formed by the above-mentioned hinge means.

For releasable connection of the knife with the needle body can serve a releasable connection means. This is inventively formed by a latching device which is arranged at a location which is spaced from the positive-locking holding means. The latching device may be formed, for example, by a latching tongue formed on the blade, which can engage in a latching manner with a second projection provided in the slot. The latching tongue is preferably transverse to the Needle body longitudinal direction oriented. Based on the defined by the positive connection means pivot axis, the latching tongue is preferably oriented in the circumferential direction. The latching tongue is in turn preferably one-piece component of the knife. This can be achieved by providing the knife with slot-like recesses between which a tongue formed from the material of the knife remains. This is preferably provided at its free end with a detent recess which can engage the needle body.

The releasable connection means, for example in the form of a latching device may be formed at the same location as the holding means, it then forms the holding means. The latching device may for example be formed by a survey that protrudes into an opening of the knife and thus holds this by means of positive locking and fixed. The survey may be in the form of a pin formed from the material of a slot wall. The size and dimension of the opening of the cutting blade and the survey of the slot wall can be coordinated so that the cutting blade is axially fixed in the slot of the needle body after assembly. For radial fixation, a second latching device of the same or a similar type can be arranged at a distance from the first. Preferably, one of these two latching means is arranged in the front end region of the cutting blade and the other holding or latching means in the rear end region of the cutting blade. To fix the cutting blade can serve two surveys per opening in the cutting blade. Each elevation starts from a slot wall and projects into the opening of the cutting blade. Both elevations can be mirror-symmetrical and can be exactly opposite each other. To fix the cutting blade in the needle body, an opening can take a shape that deviates from the shape of a survey. For example, an opening may be formed as a slot be. The elevations of the two slot walls can then preferably be arranged laterally offset, so that a survey in the rear region of the elongated hole projects and the opposite elevation protrudes in the front region of the elongated hole. The height of the surveys can be made very small. If two elevations protrude into an opening, the sum of the height of both elevations may be smaller than the width of the cutting blade or the length of an opening. Between the two surveys which protrude into an opening is then preferably a distance. The elevations may be formed in a variety of forms, they may for example have a cylindrical, or a spherical or otherwise curved shape.

In a preferred embodiment of the cutting needle an effective between the knife and the needle body Axialarretierungseinrichtung is provided. This serves to keep in operation on the knife acting axial forces, in particular of the locking device of the knife and to ensure that the knife does not move in operation in the axial direction of the needle body. The Axialarretierungseinrichtung may be formed by positively cooperating means which are effective between the knife and the needle body. Preferably, the Axialarretierungseinrichtung contains at least one contact surface for the knife, said contact surface is directed against axial movement of the knife on the latching device towards. That is to say, the contact surface of the axial locking device provided, for example, on the needle base body preferably looks toward the positive connection means. Such a contact surface may for example be formed on a web provided in the slot, which is arranged between the latching device and the positive connection means. Alternative axial locking means may be provided which act, for example, on an end face of the knife.

Regardless of the specific design of the connecting means, which stores the knife on the needle body, the present invention allows a simple and quick change of worn knives and thus a considerably accelerated maintenance of knitting machines. In addition, the present invention enables the separate production of knives and needle bodies from different, each optimized for the purpose of materials with different optimized for each target production technologies. It is also possible to provide needle body and knife separately and in different numbers, so that a plurality of knives can be successively inserted and worn on a needle body.

• Figur 1 die erfindungsgemäße Schneidnadel in einer perspektivischen Übersichtsdarstellung in ausschnittsweiser Ansicht,
• Figur 2 die Schneidnadel nach Figur 1 in einer vereinfachten Seitenansicht,
• Figur 3 die Schneidnadel nach Figur 1 und 2 in einer teilweise geschnittenen Seitenansicht,
• Figur 4 die Schneidnadel nach Figur 3 beim Messerwechsel,
• Figur 5 eine abgewandelte Ausführungsform der Schneidnadel in einer teilweise aufgeschnittenen Seitenansicht,
• Figur 6 eine abgewandelte Ausführungsform der Schneidnadel in einer teilweise aufgeschnittenen Seitenansicht und
• Figur 7 einen Ausschnitt der Schneidnadel nach Figur 6 in Draufsicht.

Further details of advantageous embodiments of the invention will become apparent from the description, the drawings and claims. The description is limited to essential aspects of the invention and other circumstances. The drawings illustrate further details and are to be used by the skilled person in the usual way complementary to the description. Show it:

• FIG. 1 the cutting needle according to the invention in a perspective overview in a sectional view,
• FIG. 2 the cutting needle after FIG. 1 in a simplified side view,
• FIG. 3 the cutting needle after FIG. 1 and 2 in a partially sectioned side view,
• FIG. 4 the cutting needle after FIG. 3 when changing blades,
• FIG. 5 a modified embodiment of the cutting needle in a partially cutaway side view,
• FIG. 6 a modified embodiment of the cutting needle in a partially cutaway side view and
• FIG. 7 a section of the cutting needle after FIG. 6 in plan view.

In FIG. 1 a cutting needle 1 is illustrated, which has an elongate base body 2, at the end of a hook 3 is formed. The main body 2 is configured to communicate with a drive device. He can do that as well FIG. 2 shows, be provided at a suitable remote from the hook 3 place with a foot 4. This is adapted to cooperate with the needle lock of a knitting machine, whereby the needle body 2 in the needle channel of a needle bed, such as a dial or a knitting cylinder, ie axially in the longitudinal direction L is moved. The example in rectangular cross-section needle body 2 has, as FIG. 1 illustrates, adjacent to the hook 3, a slot 5 in which a knife 6 is held. The slot 5 preferably starts in the immediate vicinity of the hook 3 in a throat region 7 and extends beyond the needle breast 8. It is straight and is bounded by two slot flanks. As FIG. 3 shows the slot 5 goes from the needle top 9 to the needle back 10 and thus forms an opening. The slot 5 is thus open both to the needle top 9 and to the needle back 10. It is noted, however, that the slot 5 may be closed to the needle back 10 as needed.

The slot 5 serves to support and secure the blade 6, which can be designed as a razor blade as a flat flat plate. It thus has two facing away from each other flat sides, which are held between the slot flanks without significant play. It is ground on its edge rising away from the throat 7, so that there is formed, as shown, a straight or, if necessary, also otherwise shaped cutting edge 11. This is preferably at an acute angle to the shaft longitudinal direction L.

The knife 6 and the needle body 2 of the cutting needle 1 are preferably made separately and subsequently joined together. Accordingly, they can consist of different materials, for example different steels. For example, the material of the knife 6 is optimized so that the wear of the cutting edge 11 in the intended use is minimal. On the other hand, the material of the needle body 2 can be optimized in terms of toughness or other properties. In addition, both the knife 6 and the needle body 2 can be provided with optimized wear-reducing coatings of different types.

It is effective between the needle body 2 and the knife 6 preferably at least one positive retaining means 12 which is arranged for example on the hook-side end 13 of the slot 5. The holding means 12 is formed, for example, by a first projection 14 formed on the end 13 of the slot 5 in conjunction with a notch 15 provided in the associated end of the knife 6. The first projection 14 may be formed between end surfaces of the slot 5, each of which is followed by a circular arc. How the comparison of FIGS. 3 and 4 shows, the positive-locking means 12 forms a kind of hinge, a in FIGS. 3 and 4 defines perpendicular to the plane of the drawing and thus oriented transversely to the main body longitudinal direction L hinge axis. This allows the knife 6 in the slot 5 in and out of this herauszuschwenken how FIG. 4 indicated by a dot-dashed circular arc 16.

At a location remote from the holding means 12, a preferably flat torque support surface 17 is formed on the needle base body 2, which serves as a support surface for a correspondingly shaped support surface 18 of the blade 6 which is likewise planar in the present exemplary embodiment. The moment support surface 17 is oriented approximately radially to the center of rotation of the holding means 12 and thus transversely to the circular arc 16. It supports the blade 6 when corresponding forces act on the cutting edge 11 when cutting threads, which then generate torques that press the knife 6 about the imaginary hinge axis of the positive holding means 12 in the direction of the circular arc 16 against the Momentenabstützfläche 17.

To secure the knife 6 in its working position FIG. 3 a fastening means is provided, which is formed by a latching device 19 in the present embodiment. The latching device 19 comprises two latching engageable members, one of which is formed on the Nadelschaf t 2 and the other on the knife 6. In the exemplary embodiment, these members are formed by the needle shaft 2 by a second projection 20 which is formed at the end 21 of the slot 5 away from the hook 3. On the part of the knife 6, the locking member is formed by a tongue 22, which is an integral part of the knife 6. The second projection 20 is limited in the present embodiment of two arcuate curved surfaces. It forms a projecting towards the hook 3 tip.

The tongue 22 is made of the material of the knife 6. It is separated by two slots 23, 24, ie cut out of the flat body of the knife 6 and thus forms an exposed elongated portion of the knife 6. At one end, it is seamless and seamless connected to the remaining material of the knife 6. Its other end is resiliently movable towards and away from the notch 15. This other resiliently movable end is also provided with a recess or notch 25 which is arranged to receive the tip of the second projection 20 can, when the support surface 18 rests against the torque support surface 17.

In addition, the cutting needle 1 may have an axial locking device 26 to which an abutment 27 formed on the base body 2 and a contact surface 28 formed on the blade 6 belong. The abutment 27 may be formed by a web 5 passing through the web, which is integrally connected to both the slot 5 bounding cheeks. The web or the abutment 27 preferably has a facet 29 oriented toward the hook 3. This is associated with the contact surface 28, which points away from the holding means 12 and the hook 3. The contact surface 28 may be part of a boundary of a mouth-like opening 29 which is attached to the knife 6 at the edge 11 opposite the cutting edge.

The cutting needle 1 works as follows:

In operation, the cutting needle 1 performs a back and forth along the shaft longitudinal direction L movement. The hook catches 3 threads and shapes them into half-stitches or stitches. If these are pushed to the knife 6 or the cutting needle 1 is driven so far that the cutting edge 11 of the knife 6 moves through the mesh, the mesh is cut. In this case, a force directed away from the hook 3 is exerted on the knife 6, among other forces. This force supports the contact surface 28 on the abutment 27. The force is thus kept away from the latching device 19. The knife 6 is securely held in the needle body 2.

The knife change goes as follows:

The knife 6 is pulled out of the slot 5 and pivots it, as it FIG. 4 shows. The tongue is 22 resiliently and thus slides off the second projection 20. In addition, the knife 6 is pivoted away from the abutment 27, so that it from the in the FIG. 4 shown position entirely out of the slot 5 can be lifted out. A new knife 6 is used by this is first introduced with its hook-side end in the slot 5, so that its notch 15 is placed on the first projection 14. Then, the knife 6 is pivoted along the circular arc 16 into the slot, wherein the notch 25 of the tongue 22 engages the second projection 20 and the support surface 18 on the Momentenabstützfläche 17 finds their abutment. This process can be performed without removing the cutting needle 1 from its needle bed.

FIG. 5 illustrates a modified embodiment in which the Axialarretierungseinrichtung 26 is not, as stated above, between the ends 13, 21 of the slot but seen from the perspective of the hook 3 behind the knife 6 is arranged. This embodiment is suitable for example for cutting needles 1 'with a relatively high shaft, ie greater distance between the needle top 9 and the needle back 10. Within a slot extension 5', the abutment 27 'may be provided which cooperates with an end face 31 of the knife 6. The end surface 31 thus forms a contact surface which corresponds to the contact surface 28. The abutment 27 'may be formed by a pin which is inserted into a corresponding, the needle body 2 transversely passing through opening. The pin can also be formed by projections which project from the flanks of the slot extension 5 'toward one another. Such half-pegs can be produced similar to the production of tongue bearings in latch needles.

FIG. 6 illustrates a modified embodiment of a cutting needle according to the invention 1. This cutting needle has an Axialarretierungseinrichtung 26 ', a holding means 12' and a latching device 19 ', which differs from the means described above. Otherwise, reference is made to the above description when using the same reference numerals. It is between the needle body 2 and the knife 6 preferably at least one positive retaining means 12 'is effective, which is arranged for example in the end region of the blade 6 at the hook-side end 13 of the slot 5. The holding means 12 'is formed for example by a notch 15' in the form of an opening which is arranged transversely to the longitudinal direction L of the needle main body 2. In this opening 15 'which is formed in the form of a slot, projecting from the slot wall 34, a first projection 14' and starting from the slot wall 35, a first projection 14 "( FIG. 7 ). The slot 15 'is limited in the direction of the hook 3 by an end 33 and opposite by an end 32. The first projection 14 'and 14 "may be formed of the material of the slot wall 34, 35. The first projections 14' and 14" may be positioned spaced apart in the axial direction. In the embodiment according to FIG. 7 the first projection 14 'cooperates with the end 33 of the opening 15' and the first projection 14 '' with the end 32 of the opening 15 'and form a positive fit with the ends 32 and 33. The surface of the first projection 14' and 14 '' may be in the form of a spherical section and comprise part of a spherical surface. Their height of the first projection 14 ', 14 "can be made small and thus only slightly project into the opening 15' of the knife 6. To enable the clipping of the knife into the slot 5, the height and positioning of the first projection 14 ', 14 "depending on the flexibility of the slot walls 34, 35 determines. High flexibility of the slot walls 34, 35 allows a large height of the first projection 14 ', 14 "and the positioning in a near-end region of the knife 6. Stable slot walls 34, 35 require a small height of the first Projection 14 ', 14 "and the positioning as possible in the middle of the longitudinal extent of the knife. 6

The latching device 19 'according to the embodiment according to FIG. 6 is spaced from the holding means 12 '. It is essentially the same as the holding means 12 'is formed. It has a notch 25 'in the form of a bore, which passes through the knife 6 transversely to its longitudinal direction. In this opening 25 'projects from the slot wall 34, a second projection 20 "and starting from the slot wall 35, a projection 20". Both protrusions 20 'and 20 "are equally positioned in the axial direction, they face each other and form a positive fit with the opening 25. For the height and the position of the second protrusion 20' and 20", the above-mentioned criteria of the first protrusion apply 14 'and 14 "accordingly.

In addition, the cutting needle 1 according to FIG. 6 an Axialarretierüngseinrichtung 26 ', to which a formed on the base body 2 abutment 27' and formed on the knife 6 contact surface 28 'belong. The abutment 27 'may be formed by a slot 5 limiting surface or edge. The edge or abutment 27 'preferably has a facet 29' oriented toward the hook 3. This is associated with the contact surface 28 'which points away from the holding means 12' or the hook 3.

The knife 6 of a cutting needle 1 according to the invention FIGS. 6 and 7 is changed by using a means such as a pair of flat-nose pliers (not shown), the knife 6 detected on its flat sides and after: above in the direction of the needle top 9 is withdrawn. In this case, the slot walls 34, 35 are resilient, so that the projections 14 ', 14 "and 20', 20" the openings 15 'and 25' share and the knife 6 can be removed. A new knife 6 can be used in the free Slot 5 are introduced by being introduced from the needle top 9 in the direction of the needle back 10 with an aid, wherein the projections 14 ', 14'',20', 20 "with the openings 15 'and 25' form a snap closure.

It has been provided a cutting needle 1 for knitting machines and similar applications, which has a needle body 2, to which a knife 6, preferably by a latching device 19, 19 'is releasably held. Such a cutting needle 1 reduces maintenance costs of knitting machines and opens up ways for the production engineering and material optimization of the needle body 2 and knife 6.

reference numeral

1, 1 '

cutting needle

2

Needle body, basic body

3

hook

4

foot

L

Stem longitudinally

5

slot

5 '

Slot extension

6

knife

7

Kehlbereich

8th

needle breast

9

Needle top

10

needle back

11

cutting edge

12, 12 '

holding means

13

The End

14, 14 ', 14 "

first advantage

15, 15 '

Notch, opening

16

arc

17

Momentenabstützfläche

18

supporting

19, 19 '

locking device

20, 20 ', 20 "

second lead

21

The End

22

tongue

23, 24

slot

25, 25 '

Notch, opening

26

Axialarretierungseinrichtung

27, 27 '

abutment

28, 28 '

contact surface

29, 29 '

facet

30

opening

31

end face

32, 33

The End

34, 35

diaphragm wall

Claims (7)

1. Cutting needle (1) for a knitting machine,
   with a needle body (2) which is provided with a hook (3) at one end, and
   with a cutter (6) which is detachably connected to the needle body (2),
   wherein the needle body (2) is provided with at least one form-fit holding means (12, 12') for mounting the cutter, and
   the holding means (12, 12') is formed by a first protrusion (14, 14', 14") and a notch (15, 15'),
   characterized in that
   a detent device (19, 19') is provided which serves to hold the cutter (6) on the needle body (2),
   and that the detent device (19, 19') is formed by a second protrusion (20, 20', 20") and a notch (25, 25'),
   wherein the first protrusion (14, 14', 14") and the second protrusion (20, 20', 20") are arranged at points spaced apart from each other at ends of a slot (5) of the needle body (2).
2. Cutting needle according to claim 1, characterised in that the needle body (2) has a slot (5) for receiving the cutter (6).
3. Cutting needle according to claim 1, characterised in that the needle body (2) is provided with a moment-support face (17) for the cutter (6).
4. Cutting needle according to claim 1, characterised in that the detent device (19) comprises a detent tongue (22) formed on the cutter (6).
5. Cutting needle according to claim 4, characterised in that the detent tongue is formed by an exposed linear portion of the cutter (6).
6. Cutting needle according to claim 1, characterised in that it comprises an axial locking device (26).
7. Cutting needle according to claim 6, characterised in that the axial locking device (26, 26') has at least one contact face (28, 28', 31) for the cutter (6) which counters an axial movement of the cutter (6) towards the detent device (19, 19').

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