EP0719881A1 - Stamped knitting tool for textile machines, particularly for knitting machines - Google Patents

Abstract

The stamped needle, for a knitter, has a shaft (1) with at least one butt (2), and a free zone (6) filled with pref. a plastics material (8), e.g. polyamide-12, polyethylene, polyurethane or PTFE, and or metallic organic material, firmly bonded to the shaft (1). The edges (14-16) of the free zone are chamfered inwards, at least in stretches, with chamfered sections (19,20) extending into the filling material.

Description

The invention relates to a punched knitting tool for textile machines, in particular knitting or knitting machines, with a shaft which carries at least one foot and in which at least one space is formed, which is filled with a heterogeneous material, in particular a plastic, which is firmly attached to the Shaft is connected.

“Knitting tools” are to be understood here as tongue needles, point needles, slide needles, needles without tongues, for example plush hooks for the manufacture of plush goods as well as sinkers and the like.

From DE-PS 3 314 809 a punched knitting tool of the type mentioned is known, in the shaft at least one free space is arranged, which is designed in the form of an elongated hole, the longitudinal axis of which is aligned parallel or coaxially to the longitudinal axis of the shaft. This slot is through two of the Upper vertical edge of the upper edge of the shaft is bounded by vertical guide parts and two narrow webs connecting them, which are arranged parallel to one another. The free space is filled with a vibration-damping material that is firmly connected to the needle shaft. This vibration-damping material is usually an elastic plastic material with high damping properties, but the use of other materials is not excluded. Embodiments with one or more such free spaces completely enclosed by the webs and the guide parts are described.

As shown by practical experience, the vibration behavior of the knitting tools is advantageously influenced by the vibration-damping material contained in the respective free space. It is possible to dissolve the knitting tools into a highly elastic structure with web heights of at most 1.1 mm and to use the knitting tools over long periods of operation at high working speed, without causing web breaks as a result of material fatigue or broken hooks to any significant extent.

Since the vibration-damping material filling the free space can only develop its effect if it is firmly connected to the shaft material along the edge of the free space, knitting tools have also been subjected to bending in particular in the case of very thin and in operation in the area of such a free space due to laterally acting forces on bending additional measures for anchoring the plastic filling in the free space have already been taken. For this purpose, it is known from the applicant's EP-A1 0 282 647 to provide the space-free web and / or guide sections with a profile. The profiling can have areas of reduced wall thickness, which are either arranged in a localized manner or in the form of strips over the entire outline - or part of it - of the free space. These areas of reduced wall thickness protrude into the plastic material filling the free space and contribute to its positive anchoring on the shaft.

In practice it has been found that the production of knitting tools, in particular needles with free spaces, which are formed with profiled areas of reduced shaft thickness at the edges, is relatively difficult and expensive. Separate punching tools specially designed for this embodiment of the anchoring of the plastic material are required, and in particular in the case of free spaces limited by webs of low height, precautions must be taken to prevent the thin webs from being distorted during manufacture. The areas of reduced shaft thickness adjoining the shaft via right-angled shoulder areas can also lead to localized stress peaks ("tension knots") which affect the life of the knitting tool when the knitting tools are subjected to high dynamic loads.

The object of the invention is therefore to remedy this and to create a knitting tool of the type described, in which, with simplified manufacture, a perfect anchoring of the heterogeneous material filling the respective free space in the shaft is ensured on the shaft.

To achieve this object, the knitting tool according to the invention has the features of claim 1.

The shaft is beveled at least in places along the edge of the free space towards the free space, the beveled areas projecting into the heterogeneous material filling the free space.

The bevel on the edge of the free space results in a secure external anchoring of the material filling the free space, in particular plastic. The chamfered areas can in particular be embossed into the shaft, which can be done with the aid of a simple, inexpensive stamp which has a long service life. Since the displaced material flows towards the free space during the embossing process, the unembossed shaft areas are not affected by the embossing process. This is particularly important if the space to the upper and / or lower edge of the shaft is limited by webs of low height, the cross-section of which is retained.

It is particularly advantageous if the beveled areas are delimited towards the free space by a fillet, which, as the second internal positive locking anchoring of the material filling of the free space, provides additional hold. This fillet is generated automatically during the stamping process because the shaft material is pushed inwards towards the free space. Basically, however, embodiments are also conceivable in which the fillet is produced differently, for example by machining or by means of an infiltration.

The chamfered areas advantageously have an essentially identical chamfer angle on both shaft sides, but embodiments are also conceivable in which, for special reasons, different chamfer angles are provided or a chamfer is only arranged on one shaft side.

Depending on the type and design of the knitting tool, the chamfered areas can be locally limited along the outline of the free space or extend around the closed outline of the free space.

So with knitting tools, the shank of which is Is designed with at least one free space in the form of an elongated hole, which is bounded towards the upper and lower edge of the shaft by a web of low height, the arrangement should be such that there are bevelled areas on the webs. The parts of the free space outline which connect the two webs at the end face to one another, as a rule semicircularly curved, can, in certain embodiments, at least partially also be left without bevels, ie unprocessed, if this appears expedient in view of a favorable stress distribution in the shaft material. Of course, it is also possible that the chamfered areas also extend entirely over these curved outline parts of the free space.

Particularly in the case of dynamically highly stressed knitting tools, such as needles for high-performance knitting machines, it has proven to be advantageous to design at least one of the curved outline or boundary areas of the free space to be essentially elliptical, the bevels then generally extending over the entire curved area. This results in a tension-friendly transition between the straight and the curved parts of the free space outline, which leads to a particularly high dynamic resistance of the knitting tool.

Further designs of the new knitting tool are the subject of subclaims.

• Fig. 1 ein Strickwerkzeug gemäß der Erfindung in Gestalt einer Zungennadel, in schematischer Darstellung und in einer Seitenansicht,
• Fig. 2 die Zungennadel nach Fig. 1 in der Draufsicht,
• Fig. 3 die Zungennadel nach Fig. 1 unter Veranschaulichung eines offenen, d.h. nicht mit einem heterogenen Material gefüllten Freiraums, im Ausschnitt und in einem anderen Maßstab,
• Fig. 4 die Zungennadel nach Fig. 3 geschnitten längs der Linie IV-IV der Fig. 3, in einem anderen Maßstab sowie im Ausschnitt,
• Fig. 5 den Umriß des mit Anschrägungen versehenen Freiraums der Zungennadel nach Fig. 3 in einer vergrößerten Teildarstellung und im Ausschnitt,
• Fig. 6 die Zungennadel nach Fig. 3 mit einem heterogenen Material ausgefülltem Freiraum in einer Darstellung entsprechend Fig. 3,
• Fig. 7 die Zungennadel nach Fig. 6 geschnitten längs der Linie VII-VII der Fig. 6 in einem anderen Maßstab,
• Fig. 8 die Zungennadel nach Fig. 1 in einer abgewandelten Ausführungsform im Ausschnitt und in einem anderen Maßstab und
• Fig. 9 die Zungennadel nach Fig. 8 in einem vergrößertem Ausschnitt zur Veranschaulichung der Umrißgestalt eines Freiraumes.

Exemplary embodiments of the subject matter of the invention are shown in the drawing. Show it:

• 1 is a knitting tool according to the invention in the form of a latch needle, in a schematic representation and in a side view,
• 2 shows the top view of the latch needle according to FIG. 1,
• 3 shows the latch needle according to FIG. 1, illustrating an open space, ie a space not filled with a heterogeneous material, in the detail and on a different scale,
• 3 cut along the line IV-IV of FIG. 3, on a different scale and in the detail,
• 5 shows the outline of the chamfered free space of the latch needle according to FIG. 3 in an enlarged partial view and in a cutout,
• 6 shows the tongue needle according to FIG. 3 with a heterogeneous material filled free space in a representation corresponding to FIG. 3,
• 7 cut along the line VII-VII of FIG. 6 on a different scale,
• Fig. 8 the latch needle of FIG. 1 in a modified embodiment in the cutout and on a different scale and
• FIG. 9 the latch needle according to FIG. 8 in an enlarged detail to illustrate the outline shape of a free space.

The latch needle shown in FIGS. 1, 2 has a needle shaft 1, which is usually punched out of strip steel and has two molded feet 2 on its upper side and to which a needle head 3 with the needle hook 4 is connected on one side. The needle tongue cooperating with the needle hook 4 is indicated at 5.

In the illustrated embodiment, four through slots 6 are spaced apart from one another in the axial direction, each of which forms a free space which is filled with a heterogeneous material 8 in the manner shown in FIGS. 6, 7. The heterogeneous material is firmly connected to the shaft 1 along the edge of each elongated hole 6. It usually consists of a plastic, preferably a polyamide-12, polynrethane, polyethylene or polytetrafluoroethylene or the like, but in principle this also means non-organic substances, for example of a metallic type.

Each elongated hole 6 is delimited on its long sides by two mutually parallel webs 9, 10 and on the end face by two guide parts 13 extending from the upper edge 11 of the shaft to the lower edge 12 of the shaft. Each foot 2 is supported by one of the guide parts 13. The two webs 9, 10 lying on the upper needle shaft edge 11 and on the lower needle shaft edge 12 have a low height of preferably approximately 1.1 mm and less. Their length is advantageously more than 8 mm. In the embodiment shown in FIGS. 1 to 7, the outline of each elongated hole 6 is thus limited to the long sides adjoining the two webs 9, 10 by essentially straight lines 14, 15, which are formed by two semicircular curved lines 16, 17 are connected to one another, of which the associated radius is indicated at 18 in FIG. 3.

Along the edge of each of one of the elongated holes 6 formed free space, the shaft 1 is tapered inwards towards the free space, as can be seen in particular from FIGS. 3 to 5. The narrow, strip-shaped, beveled areas are designated 19, 20. They lie on both sides of the shaft 1 and have essentially the same bevel angle 21, which is 35 ° in the exemplary embodiment shown. It can also be selected differently depending on the shaft thickness 22 and the type of material filling 8 used as well as the conditions of use and conditions of the knitting tool. It is preferably in a range of approximately 10 to 80 °. The bevel angles 21 can also have different sizes on both sides of the shaft 1, which should be pointed out for the sake of order. Finally, it should be mentioned that the bevels 19, 20 in the illustrated embodiment extend in the form of a wedge in each case towards the longitudinal median plane of the shaft 1 indicated at 23 in FIG. 4 and lie with their (imaginary) apex line on this median plane. Embodiments are also possible in which this (imaginary) apex line is offset on one or the other side with respect to the longitudinal center plane 23. The beveled areas 19, 20, which in the present case are of equal width, can also have a width that is different from one another.

4, 5 show that the beveled region 19 extends on both sides of the shaft substantially over the length of the two straight contour lines 14, 15 of the elongated hole 6 and the semicircular curved contour line 17 of the elongated hole 6 connecting them, which extends in close to foot 2. On the opposite end face of the elongated hole 6, the beveled area 19 ends on both sides of the shaft at 25 in the axial direction somewhat in front of the area in which the straight outline 14 or 15 merges into the semicircular curved outline 16. The tapered area 20 extends then on both sides of the shaft over part of the semicircular curved line 16, wherein it is arranged symmetrically to the longitudinal axis indicated at 26. Due to the free, ie not beveled, shaft area between the bevels 19, 20 at 27, there is a favorable influence on the stress distribution occurring during operation in the shaft 1. Embodiments are also conceivable in which such non-beveled areas at other points along the Outline of the respective elongated hole 6 are provided. For example, in the region of the end face facing the foot 2, a bevel 20 can only be present over part of the length of the semicircular contour line 17.

The equally shaped, beveled areas 19, 20 lying on both sides of the shaft 1 are each delimited towards the free space by a fillet 27, which is arranged symmetrically to the longitudinal center plane 23.

The space delimited by each elongated hole 6 is, as already mentioned, injection molded with vibration-damping plastic material 8, which, as can be seen from FIG. 7, is flush with the two shaft side walls. The beveled areas 19, 20 and the fillet 27 protrude into the material filling 8 and thus result in a form-fitting anchoring for the plastic adhering to the slot edge. The fillets 27 form an additional second anchoring means. Embodiments are also conceivable in which preformed plastic parts are pressed into the elongated holes 6 and anchored therein in a form-fitting manner at the edge.

The chamfers in the chamfered areas 19, 20 are stamped on the shaft 1. For this purpose, an embossing stamp indicated at 28 in FIG. 4 is used, the length of which is matched to the respective elongated hole 6 and partially corresponding to the beveled areas 19, 20 has circumferential bevels 29. In the embossing process indicated by an arrow 30 in FIG. 4, the shaft material is pushed inwards on the outline of the elongated hole 6, the groove 27 being formed at the same time. The chamfered areas 19, 20, which practically enclose the entire contour of the elongated hole 6, provide excellent anchoring of the plastic 8, preventing local breaking out. The cross section of the two webs 9, 10 is retained during the embossing process and offers no approach to break points. The latch needle thus has a very low coefficient of friction in the needle channel of the associated needle bed.

In the modified embodiment shown in FIGS. 8, 9, the chamfered area 19 extends over the entire closed outline of the free space delimited by the elongated hole 6. Deviating from the embodiment according to FIGS. 1 to 7, however, the semicircular contour line 16 or 17 (which is indicated by dashed lines in FIG. 9 for comparison), which connects the two straight contour lines 14, 15 on the front side, is replaced by an essentially partially elliptical contour line 17a , which transitions into the straight outline 14, 15 without a paragraph. This configuration results in a better stress distribution in the region of the front ends of the free spaces when the latch needle is loaded, which contributes to the fact that the ends of the webs 9, 10 experience a gentler change in cross-section at the transition into the elliptical contour lines 17a.

Contour lines 17a which are partially elliptically curved can be provided on each end face for each elongated hole 6, but it is often sufficient to design only one end face accordingly, while the part-circular outline line 17 is used on the other end face. The partially elliptical outline 17a can face a foot 2 or the needle head 3 (FIG. 1).

Deviating from the exemplary embodiments shown, other embodiments of knitting machine needles and generally knitting tools are of course also possible, which for example have only a single foot 2 and / or an elongated hole 6, the outline of the respective free space also being able to be designed differently from an elongated hole, for example in Circular, slot, V shape and the like.

Claims (9)

Stamped knitting tool for textile machines, in particular knitting or knitting machines with a shaft (1) which carries at least one foot (2) and in which at least one free space (6) is formed which is filled with a heterogeneous material (8), in particular a plastic which is firmly connected to the shaft (1), the shaft being beveled inwards at least in places along the edge (14, 15, 16, 17, 17a) of the free space and the beveled areas (19, 20) protrude into the heterogeneous material (8). Knitting tool according to claim 1, characterized in that the chamfered areas (19, 20) are delimited towards the free space (6) by a groove (27). Knitting tool according to claim 1 or 2, characterized in that the chamfered areas (19, 20) are embossed in the shaft (1). Knitting tool according to one of the preceding claims, characterized in that the chamfered areas (19, 20) are arranged on both sides of the shaft. Knitting tool according to one of the preceding claims, characterized in that the chamfered areas have a substantially identical chamfer angle (21). Knitting tool according to claim 5, characterized in that the bevel angle (21) is between 10 and 80 ° and is preferably approximately 35 °. Knitting tool according to one of the preceding claims with a free space in the form of an elongated hole, which is delimited towards the upper and lower edge of the shaft by a web (9, 10) of low height characterized in that beveled areas (19) are present on the webs (9, 10). Knitting tool according to one of the preceding claims, characterized in that beveled areas (19, 20) extend partially or entirely into or over curved outline areas (17, 17a) of the free space (6). Knitting tool according to Claim 8, characterized in that at least one (17a) of the curved contour regions is essentially elliptical.

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