EP2251469B1 - Flat knitting machine with sinkers - Google Patents

Description

The invention relates to a flat knitting machine with opposing needle beds and longitudinally slidably disposed needles, each needle is associated with a hold-down plate, which is arranged adjustable between a closed position and an open position.

The use of hold-down boards in flat knitting machines has been known for some time. For example, describes the DE 39 35 763 A1 a flat knitting machine with hold-down boards, which act in addition to rigidly arranged mesh images and which are pivoted by means of control cams in their closed and open positions. The hold-down surfaces of the sinkers are angled, resulting in a hook-shaped profile of the top of the hold-down boards. In the closed position, the hold-down surface reaches relatively far below the plane defined by the underside of the needles. Due to this pronounced closed position and the hook-shaped design of the hold-down boards, while these can fulfill their hold-down function outstandingly, they exert a relatively high force on the loop to be retained. The tension created by this force in the mesh can become so great that the mesh bursts when the needle in which it is held, is driven, as the needle cross-section of a latch needle constantly increases until the stitch is behind the open needle tongue. Knitted pieces with broken stitches are rejects, which is why the formation of stitches must be avoided as far as possible.

The EP 1 347 088 B1 describes a further embodiment of hold-down plates, which also have a hook-shaped tip and exercise by a deep closed position of the hold-down a similarly strong force on the mesh. Again, it can come to the bursting of stitches.

The two known hold-down plates can also be pivoted due to their storage close to the stitch formation area of the needle bed only in a relatively limited opening position. In the opening position, the hold-down surfaces of the boards are still within the hook interior of their associated needle. In particular, in the case of a hook-shaped design of the tip of the hold-down plates, it may therefore happen in individual cases that the tip of the hold-down plate pierces parts of the knitting thread, which is in the hook of a withdrawal movement exporting knitting needle and with which the new stitch is to be formed. Another retraction movement of the needle ruptures the portion of the knitting thread that has been caught by the hold-down plate. This is visible on the surface of the knitted fabric and leads to an impairment of the knitted piece.

The invention has for its object to provide a flat knitting machine, the hold-down boards allow the processing of yarns without it can come to a bursting of stitches. The object is achieved with a flat knitting machine of the type mentioned above, which is characterized in that the hold-down plate has a flat hold-down surface, which is in the closed position of the hold-down below the bottom of the associated needle, the hold-down surface and through the bottom of the Needle defined plane an angle of at most 10 ° between them.

The hold-down of the flat knitting machine according to the invention dive in its closed position to below the needle bottom and thus also cause a reliable retention of the held in the needle stitch. However, since the hold-down surface is flat and not angled hook-shaped and also includes the active surface with the plane defined by the bottom of the needle angle of 10 ° highest, the force exerted on the mesh force is significantly lower than the known hold-down plates. Also in the production of knitted pieces of thin and / or delicate yarns thus the risk of bursting a stitch can be significantly reduced. Due to the flat configuration of the hold-down surface, that is, by dispensing with a hook-shaped design of the tip of the hold-down, also injuries to the knitting yarn in the opening position of the hold-down board are much less likely than in the known hold-down boards.

If these injuries of the knitting thread are completely excluded by the tip of the hold-down plate in the open position, the hold-down surface may lie in the open position of the board in a plane which is tangent to the hook interior of the associated needle or above the hook interior. In this embodiment of the flat knitting machine according to the invention touched the knitting thread, which is in the needle hook, does not hold the hold-down plate when it is in its open position. The stitch formation can thus be undisturbed and without injuries to the knitting thread.

Further advantages arise when the hold-down plate between its closed position and its open position is adjustable by pivoting. The hold-down boards must then be mounted only pivotable and not be displaced in addition to performing a translational movement.

Expediently, the blanks of the flat knitting machine according to the invention can also be adjusted by means of control cams arranged on the carriage of the flat knitting machine. This control is cost-effective and allows in a structurally simple manner, the vote of the movement of the hold-down plates on the movement of the needles, which are also acted upon by arranged on the carriage of the flat knitting machine cams.

In a preferred embodiment of the flat knitting machine, the hold-down surface of the hold-down plate merges to form a rounded tip in an end face of the hold-down, wherein the tip in the closed position of the hold-down plate has a distance to the median plane between the opposing needle beds of at least 0.1 mm. The rounding of the tip of the hold-down board and the maintenance of a minimum distance to the center plane of the flat knitting machine ensures that there can be no collision of opposing hold-down boards of the two needle beds.

It is also advantageous if the end face of the hold-down plate in the closed position of the hold-down plate parallel to the bottom of the needle of the opposite needle bed and at a distance of at least 0.2 mm below the plane defined by the bottom of the needle level. In this embodiment, it is ensured that the hold-down plate does not hinder the movement of the needle of the opposing needle bed even in its closed position.

The flat knitting machine according to the invention can also be equipped with stitch patterns which are rigidly arranged on the needle beds and which allow the uniform formation of stitches. To facilitate the knocking off of the stitches, a take-off wire can be guided in a manner known per se through all stitch patterns.

Hereinafter, a preferred embodiment of the stitch formation region of a flat knitting machine according to the invention will be described in more detail with reference to the drawing.

Fig. 1

einen Querschnitt durch den Maschenbildungsbereich einer Flachstrickmaschine mit Niederhalteplatinen in der Schließstellung;

Fig. 2

einen der Fig. 1 entsprechenden Querschnitt mit den Niederhalteplatinen in der Öffnungsstellung;

Fig. 3

eine vergrößerte Detaildarstellung der Fig. 1;

Fig. 4

eine vergrößerte Detaildarstellung der Fig. 2.

In detail show:

Fig. 1

a cross section through the stitch formation region of a flat knitting machine with hold-down boards in the closed position;

Fig. 2

one of the Fig. 1 corresponding cross-section with the hold-down boards in the open position;

Fig. 3

an enlarged detail of the Fig. 1 ;

Fig. 4

an enlarged detail of the Fig. 2 ,

The cross-sectional view according to Fig. 1 shows the stitch forming area of a flat knitting machine arranged between the two opposing needle beds 4, 4 '. In the needle beds 4, 4 'needles 3 are mounted longitudinally displaceable, so that they can perform movements in the directions of the double arrows NB, NB'. In the example shown, the needles 3 are in their basic position. In the needle beds 4, 4 'also hold-down boards 1, rigid stitch patterns 2 and a tee wire 5 are stored. The tee wire 5 is fixed in the stitch patterns 2.

Im in Fig. 1 As shown, the hold-down boards 1 are acted upon by not shown control cams at their ends 14 and pivoted in the direction of the arrows KS, KS 'in its closed position.

Fig. 2 on the other hand shows the stitch formation area of the flat knitting machine with the hold-down boards 1 in its open position. For this purpose, the hold-down boards 1 are detected by control cams, not shown, at their ends 14 and pivoted in the direction of the arrows KO, KO 'in the open position. The opening position of the hold-down plate is mechanically limited by the abutment surface 15 of the hold-down plate, which abuts against the boundary surface 41, 41 'of the needle bed 4, 4'.

The detailed representation of the Fig. 3 shows in an enlarged view of the stitch formation region of the needle bed 4 'from Fig. 1 , From this representation it can be seen that the hold-down plate 1 in its closed position with its newly designed hold-down surface 11 a section 101 of a mesh 100 applied and thereby holds down. The hold-down surface 11 of the hold-down plate 1 is flat in the entire area above the tee wire 5. It falls short of that Bottom of the needle and forms with the plane NG ', which is defined by the underside of the needle, a maximum angle of 10 °. The hold-down surface 11 merges with the formation of a rounded tip into an end face 12 of the hold-down plate 1. The end face 12 extends at a distance of at least 0.2 mm parallel to a plane NG which is defined by the underside of the opposing needle, which is not shown here. The rounded tip 13 of the hold-down plate 1 has a distance of at least 0.1 mm to the center plane M of the flat knitting machine.

Due to the configuration and the position of the hold-down surface 11 below the plane NG ', the smallest possible hold-down force is exerted on the loop 100 and thus also the smallest possible tension in the loop 100 is generated.

Fig. 4 is one of the Fig. 3 corresponding enlarged detailed representation of the stitch formation area of the needle bed 4 ' Fig. 2 , The hold-down board 1 is in its open position. The straight hold-down surface 11 of the hold-down plate 1 extends tangentially to the inner space 35 of the needle hook 31 at the top thereof and is thus at a considerable distance above the knitting thread of the loop 100. Thus, the possibility that the tip 13 of the hold-down plate 1 in the knitting thread of the stitch 100 can prick, practically impossible.

Claims (8)

1. Flat bed knitting machine with opposing needle beds (4, 4') incorporating longitudinally displaceable needles (3), whereby a hold-down sinker (1) is allocated to each needle (3), wherein said sinker is arranged to move between a closed position and an open position, characterised in that the hold-down sinker (1) comprises a flat hold-down face (11) which is located under the underside of the associated needle (3) in the closed position of the hold-down sinker (1), whereby the hold-down face (11) and the plane (NG') defined by the underside of the needle (3) enclose an angle of 10° at the most between them.
2. Flat bed knitting machine in accordance with claim 1, characterised in that the holding-down face (11), in the open position of the sinker (1), lies in a plane which runs tangentially to the hook's internal space (35) of the associated needle (3) or over the hook's internal space (35).
3. Flat bed knitting machine in accordance with claim 1 or 2, characterised in that the hold-down sinker (1) is displaceable between its closed position and its open position by pivoting.
4. Flat bed knitting machine in accordance with one of the previous claims, characterised in that the hold-down sinker (1) is displaceable by means of control curves arranged on the carriage of the flat bed knitting machine.
5. Flat bed knitting machine in accordance with one of the previous claims, characterised in that the hold-down face (11) of the hold-down sinker (1) merges into a front face (12) of the hold-down sinker (1) to form a rounded tip (13), whereby the tip (13), in the closed position of the hold-down sinker (1), is at least 0.1 mm from the centre plane (M) between the opposing needle beds (4, 4').
6. Flat bed knitting machine in accordance with claim 5, characterised in that the front face (12), in the closed position of the hold-down sinker (1), runs parallel to the underside of the needle (3) of the opposing needle bed (4) and forms a gap of at least 0.2 mm below the plane (NG) defined by the underside of the opposing needle (3).
7. Flat bed knitting machine in accordance with one of the previous claims, characterised in that stitch formers (2) also are arranged rigidly on the needle beds (4, 4').
8. Flat bed knitting machine in accordance with claim 7, characterised in that a casting-off wire (5) is driven by all stitch formers (2).

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