EP0990724B1 - Thread-clamping and -severing device for knitting machines - Google Patents

Description

The invention relates to a thread clamping and cutting device for knitting machines, especially for flat knitting machines, with several clamping and cutting points and at least one Thread allocation device for feeding at least one thread to the individual clamping and cutting points.

Clamping and cutting devices are for all types of Knitting machines already known. The cutting and clamping of Knitting threads will be required if on one thread another Color or quality is changed. For circular knitting machines the thread change takes place at full knitting speed. The clamping and cutting devices used there point usually a finger-like element on the thread either assigns to the knitting needles or withholds them. In the retention position, the thread can be from a blade or Scissors severed and different clamping devices Designs are kept. For flat circular knitting machines each thread must be cut off when it emerges from a needle bed and when entering the other needle bed the needles again are fed. That is why clamp cutters have for these machines a thread clamping element running after the thread guide, that keeps the thread in tension before he is cut off. The clamping element also ensures that the thread is deeper than the exit opening of the thread guide is held so that the first needle of the next needle bed can catch the thread and knit. After the thread on the new needle bed is integrated into the knitted fabric, it will Thread end still stuck in the clamp.

Flat knitting machines are used for the production of Round tubular knitted fabrics and so-called "fully fashioned "knitting clamps and cutters needed, the resulting individual knitted pieces from which they to separate forming knitting threads. It is also used for knitted color rings for the subsequent overcasting of the knitted edges an advantage if instead of thread loops that along of the side knit edge to the next strip of the same color, at the beginning and at the end of a color range there is only a short thread end.

DE-OS 37 15 297 of the applicant shows a cutting device for flat knitting machines in which the threads are first cut if they are already several by a thread guide Needles have been fed to the knitted edge. Thereby no clamping device is required. However, surrender depending on the height of the knitted area created by the knitting thread very different lengths of thread ends on the knitted edge, which makes subsequent assembly more difficult.

In JP 59-33787 is a mechanical over cam disks controlled clamping cutting device described, the one separately controlled clamping device and a separately controlled Has scissors. With this facility everyone can Knitting threads that are processed in the knitted piece at once to be clamped and cut so that this facility can also be used with "fully fashioned" knitted fabrics.

JP 5-222652 shows a clamp cutting device that of that JP 59-33787 is very similar. There are two clamping devices provided for a cutter, whereby the threads of circular tubular knitted fabrics can also be processed are. Those threads can be held with a clamping point which are cut off after forming the arms and with the other nip the threads that after the completion of the entire piece of knitted fabric can be cut off. Two clamping points on one side of the needle bed or two on both sides a needle bed can never pick up threads individually, as it is for a corresponding colored ring knitted fabric with more than four colors would be needed. This number also ranges from Clamping points for knitted pieces with a so-called "Comb beginning" are formed, not from. An arrangement of several such clamping cutting devices enlarged side by side however the length of the thread ends from clamp to clamp and also requires a correspondingly long path for the thread guide beyond the side knitted end.

The present invention has for its object a Clamping and cutting device, especially for flat knitting machines, to create with a variety of threads clamped and can be cut, the resulting thread ends are almost the same length.

The task is done with a thread clamping and cutting device of the type mentioned at the outset according to the invention, that the clamping and cutting points in one plane transverse to Needle bed longitudinal direction are arranged. Because with this device the threads in all clamping and cutting points in one Plane perpendicular to the longitudinal direction of the needle bed, thread ends of almost the same length arise. Also needed this arrangement of the cutting and clamping points only a little additional Installation space in the machine longitudinal direction.

Another big advantage is that the thread guide only an extremely small path laterally over the end of the Knitted fabrics must result in the threads of the clamping and To be able to feed the cutting device. Preferably only a thread allocation member in the form of a pivotally mounted element provided with a hook-shaped tip and the clamping and cutting points on an arc around the The fulcrum of the thread allocation member may be arranged. The provision only one thread allocation device is not only cheaper but also easier to control. Preferably, can the thread allocation organ or the threads in an upper one Record swivel position and in a position below it Transfer the swivel position to the clamping and cutting points, so that a relatively large height difference between the Needle crossing point of the flat knitting machine and the clamping point is possible. This has the advantage that the thread that is moved away from the clamping point by a thread guide, can also be safely inserted into needles that have a larger size Distance from the clamp than the edge needles of the needle bed.

Additional benefits can be achieved if at least a thread allocation member has a separate drive. It can then the speed of the organ in the critical Optimal phases in thread take-up and thread transfer Taxes. The drive device can be designed in this way be that catching, pinching and cutting a thread like that it quickly happens that the person who moves the associated thread guide Carriage at undiminished knitting speed over the Clamp cutting device is movable. Even multi-system Sledges can go over with maximum knitting speed the clamping cutter moves away and the threads of all systems are clamped and cut. Through the separate Drive device of the clamping and cutting device is it is also possible to get stuck threads regardless of position of the sled again.

In a preferred embodiment, the clamping and Cutting points each one can be driven out in the longitudinal direction Clamping and cutting needle with one clamping surface and one Have cutting surface, the clamping surface of the clamping and Cutting needle when retracting the clamping and cutting needle with the surface of a pinch roller interacts. Such a clamp Cutting needle therefore takes on several functions. It takes over the knitting thread from the at least one thread allocation member in its thread space, clamps the thread on its clamping surface and cuts it on their cutting surface, which is with a Cutting blade interacts. None fall during the cutting process loose thread sections in the clamping cutting area could accumulate.

Preferably, the clamping surface of the clamping and cutting needle and the surface of the pinch roller with surface structures be provided, which interlock positively. Thereby can be guaranteed that all types of knitting threads, regardless of their thickness and surface condition, be securely clamped. Also a clamping of several knitting threads different thickness and structure is possible. The thread can be at each clamping and cutting point other thread guide clamped, cut and loosened. But it is also possible to thread several threads in a clamping and cutting point to clamp and cut. One can against the cutting surface of the clamping and cutting needle Swivel-mounted cutting blade without gaps thanks to spring force be pressed. The spring for pressing the cutting blade to the cutting surface of the needle can simultaneously the entire Press the needle against the pinch roller, creating a special simple mechanical construction of the clamping and cutting points is achieved.

It is also advantageous if the clamping and cutting needle after clamping and cutting one or more threads or the thread end / s with its end face when the Release the needle from the clamp. This is for solving the No additional devices required for thread ends. The single ones Clamping and cutting needles can be individually, preferably but drive by a common drive device. The drive device can expediently with a Selection mechanism for the clamping and cutting needles of the various clamping and cutting points, the also a collision between the clamping and cutting needles prevented.

Below is a preferred embodiment of one Clamping and cutting device according to the invention based on the Drawing explained in more detail.

Fig. 1

eine Detailansicht einer Flachstrickmaschine im Bereich des linken Nadelbettenendes;

Fig. 2a - 2d

eine Detailansicht der Fadenklemm- und Schneideinrichtung der Flachstrickmaschine aus Fig. 1 in unterschiedlichen Arbeitspositionen;

Fig. 3a, 3b

eine Vorder- und eine Seitenansicht einer Klemm- und Schneidnadel der Fadenklemm- und Schneideinrichtung aus Fig. 2;

Fig. 4

eine Detailansicht einer Klemm- und Schneidstelle einer Fadenklemm- und Schneideinrichtung gemäß Fig. 2;

Fig. 5

eine schematische Darstellung der Antriebsvorrichtung für die Klemm- und Schneidstellen der Fadenklemm- und Schneideinrichtung aus Fig. 2;

Fig. 6

eine schematische Darstellung des Selektionsmechanismus der Fadenklemm- und Schneideinrichtung aus Fig. 2;

Fig. 7

eine der Fig. 4 entsprechende Darstellung mit Zuführung eines geklemmten Fadens zu einem Nadelbett der Flachstrickmaschine.

Show it:

Fig. 1

a detailed view of a flat knitting machine in the region of the left needle bed end;

2a-2d

a detailed view of the thread clamping and cutting device of the flat knitting machine of Figure 1 in different working positions.

3a, 3b

a front and a side view of a clamping and cutting needle of the thread clamping and cutting device of Fig. 2;

Fig. 4

a detailed view of a clamping and cutting point of a thread clamping and cutting device according to FIG. 2;

Fig. 5

a schematic representation of the drive device for the clamping and cutting points of the thread clamping and cutting device from FIG. 2;

Fig. 6

a schematic representation of the selection mechanism of the thread clamping and cutting device of Fig. 2;

Fig. 7

a representation corresponding to FIG. 4 with feeding a clamped thread to a needle bed of the flat knitting machine.

Fig. 1 shows a section of the long side of a flat knitting machine in the area of the left end of a needle bed NB, in which a thread clamping and cutting device 10 is arranged. The device 10 could also be at the right end of the needle bed NB or at both ends of the needle bed NB be arranged. A thread guide FF1 carries a first thread F1 in a not shown, on the needle bed NB lying knitted fabric. The thread F1 continues to take on the knitting process part. A thread guide FF2 carries a second thread F2 for which the knitting process has just been completed. The thread F2 was already the thread clamping and cutting device 10 passed but not yet cut off.

2a to 2d describe the functional sequence of the thread clamping and cutting device 10 from FIG. 1. The thread clamping mouth Cutting device has eight in the example shown Clamping and cutting points 11 to 18. These are side by side arranged in one plane, in one plane across to the longitudinal direction of the needle bed NB, as shown in FIG. 1. Moreover are the clamping and cutting points on a circular arc a pivot point D of a thread allocation member 30 is arranged. The Thread allocation member 30 has a hook-shaped tip 31, with one thread, here thread F2 in the area of the thread guide FF2 and above the crossing point NK of needles 35 two opposite needle beds can be gripped, as Fig. 2b shows. At the same time, a clamping and cutting needle 40 expelled the first clamping point 11. Subsequently pivots the thread allocation member 30 down and passes the thread F2 in the thread space 41 of the clamping and cutting needle 40 (Fig. 2c). In Fig. 2d it is shown how the clamping and Cutting needle 40 is retracted into its lowest position. The Thread F2 is clamped and cut in this position. It then runs from the clamping and cutting needle 40 to the thread guide FF2. The thread allocation organ is back in its starting position swiveled back.

Fig. 3 shows a partially sectioned front view as well a side view of a cutting and clamping needle 40 Fig. 2. The thread space 41 (Fig. 3b) is used to insert the Thread. A projection 44 delimits the thread space 41 to the outside and thus prevents the thread during the retraction movement of the Slide the clamping and cutting needle 40 out of the thread space 41 can. The clamping and cutting needle 40 also has a lateral one Clamping surface 42 (Fig. 3a), which together with a Pinch roller 70 (Fig. 4) can clamp one or more threads. On the side of the needle opposite the clamping surface 42 40, a cutting surface 43 is provided, on which a Cutting blade 60 (Fig. 4) is present. When loosening the thread he can clamp by means of the end face 45 of the needle 40 conveyed out of the clamp when the needle 40 is driven out become.

4 is in addition to the clamping and cutting needle 40 also Pinch roller 70 shown together with the clamping surface 42nd the needle 40 can clamp one or more threads. For this the surface of the pinch roller 70 has a surface structure on the form-fitting in the surface structure of the Clamping surface 42 of the needle 40 engages. The pinch roller 70 is is rotatably mounted on an axis 53 and thus obstructs the inward and outward movement of the needle 40 is not. In one Bearing part 50, the cutting blade 60 is rotatable on an axis 51 stored. The cutting blade 60 is supported by a spring 52 with its cutting edge 61 without a gap on the cutting surface 43 of the needle 40 pressed. At the same time, the effect of the force exerted by the spring 52 also presses the needle 40 to the pinch roller 70 for pinching the thread.

5 shows a preferred embodiment of a common one Drive of several clamping and cutting needles shown. A not The electric motor shown drives a toothed disk 77 in the direction of arrow 76. A toothed belt 74 transmits the movement uniform on toothed pulleys 71, 72 and 73. One not Mechanism shown in more detail engages in the individual toothed disks 71, 72, 73, 77 arranged bolts 75 and transmits the rotational movement of the toothed disks 71, 72, 73, 77 in one translational movement of the clamping and cutting needles.

6 shows a selection mechanism for the total of eight Clamping and cutting needles 40/1 to 40/8 of the eight clamping and Cutting points 11 to 18 shown. A not shown Electric motor drives a pinion 85 in the two through the Double arrow 86 shown directions of rotation. This will a selection slide 80 on an arcuate path moved right or left. Through a special arrangement from selection points 81, 82, 83, 84, 85 on the selection slide 80 is achieved that only one clamping and Cutting needle 40/1 to 40/8 over a not shown Mechanics can be activated. The selection point 81 acts on the clamping and cutting needles 40/1, 40/2, the selection point 82 on the clamping and cutting needle 40/3, the selection point 83 on the clamping and cutting needle 40/4, the selection point 84 on the clamping and cutting needles 40/5, 40/6 and the selection point 85 on the clamping and Cutting needles 40/7, 40/8.

In Fig. 7 is also shown how a in a clamping and Cutting point 11 to 18 according to FIG. 4 clamped and cut Thread F is fed back to the knitting process. The Thread F is first between the clamping and cutting needle 40 and the pinch roller 70 is pinched as shown in broken lines is. The thread guide FF then moves right over the needle bed NB, and thread F is over some Stitches integrated into the knitted fabric. Then the Clamping and cutting needle 40 expelled, causing the thread end F by means of the upper end face 45 of the clamping and Cutting needle 40 is transported out of the clamp.

Claims (12)

1. Trapping and cutting device for knitting machines, in particular for flat bed knitting machines, comprising a plurality of trapping and cutting points (11 to 18) and at least one thread allocating member (30) for feeding at least one thread (F, F2) to the individual trapping and cutting points (11 to 18), characterised in that the trapping and cutting points (11 to 18) are arranged in a plane transverse to the needle bed longitudinal direction.
2. Trapping and cutting device according to claim 1, characterised in that a thread allocating member (30) is provided in the form of a rotatably mounted component having a tip (31) configured in the shape of a hook, and the trapping and cutting points (11 to 18) are arranged on a circular arc about the pivot (D) of the thread allocating member (30).
3. Trapping and cutting device according to claim 2, characterised in that the thread allocating member (30) receives the thread or threads (F, F2) in an upper rotation position and transfers it or them to the trapping and cutting points (11 to 18) in a rotation position therebelow.
4. Trapping and cutting device according to any of claims 1 to 3, characterised in that the at least one thread allocating member (30) comprises a separate drive.
5. Trapping and cutting device according to claim 4, characterised in that the drive is constructed in such a way that the threads (F, F2) are caught, trapped and cut so quickly that the slide moving the associated thread guide (FF1, FF2) can be moved over at undiminished knitting speed via the trapping and cutting device (10).
6. Trapping and cutting device according to any of claims 1 to 5, characterised in that the trapping and cutting points (11 to 18) each comprise a trapping and cutting needle (40), which may be expelled in the longitudinal direction, comprising a trapping face (42) and a cutting face (43), the trapping face (42) of the trapping and cutting needle (40) cooperating with the surface of a trapping roller (70) when the trapping and cutting needle (40) is inserted.
7. Trapping and cutting device according to claim 6, characterised in that the trapping face (42) of the trapping and cutting needle (40) and the surface of the trapping roller (70) are provided with surface structures that engage with one another in an interlocking manner.
8. Trapping and cutting device according to either of claims 6 and 7, characterised in that a rotatably mounted cutting blade (60) is pressed against the cutting face (43) of the trapping and cutting needle (40), without causing splitting, by means of spring tension.
9. Trapping and cutting device according to claim 8, characterised in that the spring (52) for pressing the cutting blade (60) against the cutting face (43) of the needle (40) simultaneously presses the entire needle (40) against the trapping roller (70).
10. Trapping and cutting device according to any of claims 6 to 9, characterised in that, after the thread (F, F2) has been trapped and cut, the trapping and cutting needle (40) removes the thread end with its end face (45) from the trapping when the needle (40) is withdrawn.
11. Trapping and cutting device according to any of claims 6 to 10, characterised in that a common drive device is provided for a plurality of trapping and cutting needles (40/1 to 40/8).
12. Trapping and cutting device according to claim 11, characterised in that the drive device is equipped with a selection mechanism for the trapping and cutting needles (40/1 to 40/8) of the various trapping and cutting points (11 to 18), which mechanism also prevents the trapping and cutting needles (40/1 to 40/8) from colliding with one another.

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