EP2813608B1 - Flat knitting machine - Google Patents

Description

In flat knitting machines, the knitting threads are usually fed to the knitting needles from one side of the needle beds via thread guides. This results in different thread tensions, depending on whether the thread guide moves away from the thread feed side or to this. To reduce this problem, stationary thread-retrieving and thread-storing devices are frequently provided on the flat knitting machines.

In the US 3,688,525 It has also been proposed to move along with the thread guide a Fadenleiteinrichtung that generates a thread loop in front of the yarn guide. The size of the thread loop can be adjusted by the distance between the Fadenleiteinrichtung and the yarn guide. However, this distance is constant during the entire carriage stroke of the machine and can only be changed when the carriage is reversed. A similar yarn guide with an associated yarn guide shows the EP 1 652 982 A1 , Even with this yarn guide, the distance to the yarn guide can only be adjusted in the carriage reversal. It has been shown that especially at elastic knitting threads or in a weft insertion with the known machine, the different yarn tension ratios can not be compensated sufficiently.

The present invention has for its object to provide a flat knitting machine with constant yarn tension ratios.

The object is achieved by a flat knitting machine having at least one needle bed and at least one insert yarn guide, which is provided along the at least one needle bed movable and provided with a Fadenleitorgan for inserting at least one knitting yarn in needles of the needle bed, and with at least one feed yarn guide, the the at least one knitting yarn feeds the at least one insertion yarn guide, which is characterized in that the two yarn guides are movable along the at least one needle bed so that their mutual distance in each direction of movement of the yarn guide during the common movement along the at least one needle bed adjustable is.

With this machine can also thread tension changes caused by a high elasticity of the knitting yarn or the braking of the yarn guide before a reversal of direction of movement, With this machine, even thread tension changes, which are caused by a high elasticity of the knitting thread or the braking of the thread guide before a reversal of direction of motion, can be compensated for sure. Thus, even with a weft insertion very constant thread tensions arise. As a result, the reversing edges of the knit are significantly improved in quality. In addition, when entering a weft thread ensures that the elasticity of the knitted fabric is constant over its entire width. Even when inserting floats from any yarn, for example, from wide ribbon yarns, the same advantages.

Further advantages arise when the insertion and the feed yarn guide with different and non-constant speeds along the at least one needle bed are movable. The mutual distance between the two yarn guides can then be arbitrarily shortened or enlarged during the movement along the needle bed (s). A non-linear change of the distance can be useful, in particular, shortly before or after the direction reversal of the movement of the two yarn guides.

To insert a weft thread, the insertion thread guide can be movable in both directions of movement at a higher speed than the leading feed thread guide along the at least one needle bed. As a result, the weft thread is as it were pushed onto the insertion thread guide, that is supplied completely tension-free this. The feed yarn guide can be repositioned already at the carriage reversal, so that this sliding yarn feed is guaranteed to insert yarn guide in both directions of movement of the yarn guide.

For the design of the feed yarn guide several possibilities come into consideration. The feed yarn guide may have a deflection roller and / or a thread brake and / or a thread clamp. If it has only one deflection roller, the thread is fed through the feed thread guide almost without friction to the insertion thread guide. Any required braking or jamming of the thread can be made by separate devices on the knitting machine. Alternatively, the feed yarn guide can brake or clamp and the thread deflection takes place via separate elements. Or the feed yarn guide can perform all these functions.

In a particularly preferred embodiment, the feed yarn guide on a pulley, between the roll halves of the knitting yarn is also braked and clamped. This thread guide has a compact design and yet can perform all three functions deflecting, braking and clamping the thread. In this case, the braking and clamping action of the deflection roller can preferably be generated by lifting the deflection roller displaceably mounted along a thread guide arm of the feed thread guide. The control of these different functions can then be realized in a similar manner as in conventional yarn guides whose Fadenführernüsschen is adjustable in height to switch the yarn guide between an active and an inactive position back and forth.

Further advantages can be achieved if at least approximately as much knitting thread can be withdrawn from a thread bobbin and stored between the feed thread guide and the insert thread guide before each movement direction change from the feed thread guide, as is required for the next knitting sequence. When reversing direction, the feed thread guide pulls the required amount of thread from the bobbin and then clamps the thread, whereby the amount of yarn at least partially required for the next row of knitting is stored between the feed yarn guide and the loading yarn guide. Subsequently, the stored thread is fed to the needles by the insertion thread guide while both thread guides move along the needle beds. The distance between the two yarn guides is reduced steadily. By this Vorlegeverfahren essentially only submitted during the reversal of direction between the yarn guides thread is entangled. The thread tension can be controlled by the amount of thread withdrawn and the relative speed of the two thread guides.

In order to be able to optimally utilize the advantages of the invention, the at least one insertion yarn guide and the at least one supply yarn guide are preferably driven by separate drive devices. The movements of the two yarn guides can then be controlled completely independently of each other.

In the following, a preferred embodiment of a yarn guide arrangement of a flat knitting machine according to the invention is explained in more detail with reference to the drawing.

The single FIGURE shows in a schematic representation on the left side of a feed yarn guide 10 and an insertion yarn guide 11 in the direction of movement 12 to the left and on the right side, the two yarn guides 10, 11 in the direction of movement 13 to the right. The two yarn guides 10, 11 are thereby moved together via yarn guide boxes 10.1, 11.1 in different tracks of a yarn guide rail not shown in the directions 12, 13, wherein the speeds of the yarn guides 10, 11, however, be different can. As a result, the distance A between the yarn guides 10, 11 can also be changed during a carriage stroke of the flat knitting machine.

The supply yarn guide 10 has a deflection roller 14, which feeds a knitting yarn 15 to a yarn guide nozzle 16 of the insertion yarn guide 11. From Fadenführernüsschen 16 of the thread 15 is then inserted into knitting needles 17 of a flat knitting machine otherwise not shown.

In both directions of movement 12, 13 of the yarn guide 10, 11, the yarn feed from the right. In both directions of movement 12, 13, however, the feed yarn guide 10 is the lead-in yarn guide 11 leading, so that in both directions of movement 12, 13 can achieve the same yarn tensions. It always results in a so-called sliding thread feed to the insertion yarn guide 11th

The deflection roller 14 may also be designed such that the thread 15 can be braked or clamped by them. Then it is possible, before changing the direction of movement 12, 13 with the supply yarn guide 10 deduct so much knitting yarn 15 from a yarn package, not shown here, as is needed for the knitting of the next course. The thread 15 is then clamped by the deflection roller 14 and stored between it and the yarn guide 16. Subsequently, during the movement of the yarn guide 10, 11 in one of the directions 12, 13 of the distance A between the yarn guides 10, 11 is shortened according to the current consumption of yarn.

Claims (8)

1. Flat knitting machine with at least one needle bed and at least one thread insertion guide (11), moveable along the at least one needle bed and equipped with a thread guide organ (16) for inserting at least one knitting thread (15) into needles (17) of the needle bed, and with at least one thread supply guide (10), supplying the at least one knitting thread (15) to the at least one thread insertion guide (11), characterised in that the two thread guides (10, 11) are moveable together along the at least one needle bed in such a way that their mutual distance (A) is adjustable in every movement direction (12, 13) of the thread guides (10, 11) during their joint movement along the at least one needle bed.
2. Flat knitting machine according to claim 1, characterised in that the thread insertion and supply guides (11, 10) are moveable with different and non-constant speeds along the at least one needle bed.
3. Flat knitting machine according to claim 1 or 2, characterised in that the thread insertion guide (11) is moveable along the at least one needle bed in both movement directions (12, 13) with a higher speed than the thread supply guide (10) travelling ahead for inserting a weft thread.
4. Flat knitting machine according to one of the preceding claims, characterised in that the thread supply guide (10) comprises a deflection roller (14) and/or a thread brake and/or a thread clamp.
5. Flat knitting machine according to claim 4, characterised in that the thread supply guide (10) comprises a deflection roller (14), between the roller halves of which the knitting thread (15) can also be braked and clamped.
6. Flat knitting machine according to claim 5, characterised in that the braking and clamping effect of the deflection roller (14) can be generated by lifting the deflection roller (14) displaceably positioned alongside a thread guide arm of the thread supply guide.
7. Flat knitting machine according to one of the preceding claims, characterised in that at least almost as much knitting thread (15) can be pulled from a thread bobbin and stored between the thread supply guide (10) and the thread insertion guide (11) by the thread supply guide (10) prior to every movement direction change, as is required for the next knitting row.
8. Flat knitting machine according to one of the preceding claims, characterised in that the at least one thread insertion guide (11) and the at least one thread supply guide (10) comprise separate drive means.

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