GB2200375A - Knitting machine roller with card clothing - Google Patents

Abstract

The roller 15 has a card clothing including a substrate 23 for the attachment of card wires 32 and an intermediate layer 24 to resiliently support the wires 32. Outer end sections 38 of the wires 32 are inclined in the direction of travel V relative to central sections 39 at a bend 36. Whereas in a conventional card clothing wires 25 have a central section 29 which extends in a straight line through the layer 24 to the pivot point 26 formed by the attachment of the wire to the substrate 23, the improved card clothing has the wires 32 shaped by a bend at 37 so that the pivot point 33 is displaced from an imaginary extension, of the central section 39 towards an inward direction of the roller 15. This has the effect of reducing the change in effective diameter as the card wires swing about the pivot points and of reducing the turning moment of the forces acting on the outer ends of the card wires. An additional layer between surface 22 and layer 23 may be provided. <IMAGE>

Description

Roller with card clothing for a knitting machine for the production of knitted Roods with combed fibres The invention relates to a roller of the kind defined in the introductory part of claim 1.

The shape and arrangement of the card wires of rollers, in particular combing rollers of this kind, are largely determined by their function, e.g. combing fibres into the hooks of the knitting needles (West German Utility Model 82 16 932). Usually the card wires comprise a bend which, relative to the definite direction of rotation of the combing roller, i.e. the direction to be produced during use, opens to the front and forms an angle of approximately 100-170 between the card wire portions adjoining it. In this case it is desirable, for a neat and uniform combing action, that the bends of all the card wires should have the same radial distance from the axis of rotation of the combing roller, so that they always travel past the knitting needles selected to receive fibres in the same radial position.

As the knitting needle hooks during passage through card clothing cannot always be guided exactly through a gap left free by the working sections of the card wires, during the combing process as a result of the impingement of the needle hooks their working sections are subjected to numerous shocks which result in tilting or bending of the card wires parallel and perpendicularly to the direction of their movement relative to the needle hooks. In order for this tilting and bending to be able to take place to a large extent in the elastic range, firstly the intermediate layer is made of a material which elastically supports the card wires, e.g. sponge or foam rubber.Secondly the card wires are mostly U-shaped (US Patent 944 031), with their cross web arranged essentially parallel to the axis of rotation of the combing roller in the substrate layer or engaging behind it, so that it simultaneously forms a pivot axis for the card wire sections extending perpendicularly away from it.

This form of card clothing, which has been commonly used for decades, is not completely satisfactory. It has turned out that the card clothing wears relatively quickly, especially by the intermediate layer becoming soft (stretching) or tearing, whereby resilient tilting or bending of the card wires and their starting position are adversely affected and uneven transfer of the fibres carried by them into the knitting needles is caused, which results in unevenness of fibre density in the finished knitted article and breakdowns in the production process. The disadvantage here is not only the wear itself, but also the fact that it is hardly possible to measure this and therefore the card clothing should for safety's sake be changed more frequently than would be necessary for reasons of the wear in itself, in order thus to exclude the possibility of producing uneven knitted goods.

Corresponding wear phenomena arise due to the fact that the working sections of the card wires as a rule also become engaged with the card clothing of an opening roller by means of which the fibres to be combed into the knitting needles are supplied to the combing roller.

Lastly, for the same or similar reasons, the card clothing of other rollers of fibre feed stations of a knitting machine for the production of knitted goods with combed fibres is also subject to wear. This applies e.g. to the feed and/or opening rollers of conventional carding devices.

It is .he object of the invention to improve the combing roller of the kind mentioned hereinbefore, to the effect that its card clothing wears less rapidly, card clothing worn out by fat igue to a large extent retains its function and hence also a high-quality knitted article with uniform fibre density is obtained while the combing roller has a long useful life.

The characterising features of claim 1 serve to achieve this object.

The invention entails the advantage that as a result of shifting of the pivot axes of the card wires compared with ordinary card clothing, the forces or torques applied to them during impingement on the needle hopks or card wires of an opening roller are favourably affected. This is associated in particular with a decrease in tearing or fatigue of the intermediate layer, whereby the service life of the card clothing is increased substantially, and results in the geometrical ratios which are important for operation being largely preserved throughout the useful life of the card clothing.

Other advantageous features of the invention are apparent from the subsidiary claims.

The invention is explained in more detail below by a practical example in- connection with the attached drawings.

These show: Fig. 1 a circular knitting machine for the production of knitted goods with combed fibres; Fig. 2 an enlarged schematic partial cross-section through a combing roller with conventional card wires and card wires according to the invention; and Figs. 3 and 4 greatly enlarged and schematised partial cross-sections of the combing roller accord ing to Fig. 2.

According to Fig. 1, a circular knitting machine for the production of knitted goods 1 with combed fibres has a base plate 2 in which are rotatably mounted a needle cylinder 4 fitted with knitting needles 3 and a sinker ring 6 fitted with.sinkers 5. The knitting needles 3 and sinkers 5 are mostly controlled conventionally at a plurality of fibre feed stations spaced apart in the circumferential direction of the needle cylinder, by cam members which act n the butts 3a of the knitting needles and corresponding bases of the sinkers 5. The fibre feed stations can moreover each be provided with a pattern device 7 by means of which the knitting needles are selected to receive fibres according to pattern.

Furthermore, at each fibre feed station is provided a feeder 9 which is attached to a frame 10 and serves to feed fibres to the knitting needles 3 selected to receive fibres, and to comb these fibres into hooks 3b of the knitting needles 3. Each feeder preferably consists of an ordinary carding device which comprises for example a drum or an opening roller 11 with card clothing 12 to which fibres in the form of a roving 13 are fed by means of a pair of feed rollers 14, and a doffer or combing roller 15 with card clothing 16 by means of which the fibres removed from the opening roller 11 are inserted in the knitting needles 3 selected to receive fibres. The card clothing 12 and 16 comprises in a known manner card wires between which are provided gaps through which travel the hooks 3b of the selected knitting needles 3.

The opening roller 11, the feed rollers 14 and the combing roller 15 are mounted rotatably in the frame 10, the axis of rotation of the combing roller 15 being marked with the reference number 17. All the rollers can be set in rotation by means which are not shown, the rotational movements generally being derived by means of belt or gear mechanisms from the drive mechanism which drives the needle cylinder or a rim gear connected to the needle cylinder. Fig. 1 shows schematically a drive mechanism 18 for the feed rollers 14, wherein in addition there is provided a control device 19 by means of which the fibres can be transferred to the opening roller 11 or the combing roller 15 in such quantities as are required by the respective pattern.Furthermore, a cover 20 at least partially surrounding the opening roller 11 and the combing roller 15 can be provided to avoid undesirable blowing of fuzz, and an extractor hood 21 for extraction of loose fibres.

The knitting needles travel past the combing roller 15 during rotation of the needle cylinder 4. At the front end of the combing roller 15, the knitting needles 3 which are to receive fibres are lifted b means of a cam member acting on the butts 3a, in such a way that the needle hooks 3b pass between the card wires of the combing roller 15 and thereby take over some of the fibres carried by them. During movement of the knitting needles 3 past the combing roller 15, the needle hooks 3b remain on a path extending essentially parallel to the axis of rotation 17. At the rear end of the combing roller 15, the knitting needles 3 are then pulled off again by a cam member acting on their butts 3a, wherein in addition a foundation thread supplied by a thread carrier can be inserted in their hooks 3b in order to form a stitch.

According to Fig. 2, the card clothing 16 normally comprises a substrate layer 23 which faces towards the cylindrical wall surface 22 of the combing roller 15, e.g. is laid on top of this and mainly consists of a textile fabric, an intermediate layer 24 attached to the substrate layer 23 and consisting of e.g. foam or sponge rubber, and a plurality of card wires 25 which are essentially U-shaped. Cross webs (not shown) of these card wires 25 are pivotably connected to the substrate layer 23 by, for example, engaging behind then in a manner known in the art (US Patent 944 031), wherein their axes are arranged parallel to the axis of rotation and thereby define, on the rear side of the substrate layer 23 or between the latter and the cylindrical wall surface 22, pivot axes which in Fig. 2 are indicated schematically with the reference number 26.From the ends of the cross webs extend generally rectilinear, perpendicularly projecting arms which traverse the intermediate layer 24, are supported in the latter and partly protrude therefrom. In this case these arms, relative to the direction of rotation which is marked by an arrow v and which is to be observed during use of the combing roller 15, are inclined rearwardly and form an acute angle a of e.g. 700 with those tangents to the cylindrical wall surface 22 which are drawn by the pivot axes 26. The working sections of the card wires 25 protruding from the intermediate layer 24 each comprise a bend 27 by which in each case an end section 28 and a central section 29 of the working sections (the central section 29 lying in the extension of the associated arm) are joined by an angle which opens in the direction of rotation (arrow v).The angle between the end sect 0 ions 28 and central sections 29 comprises, for example, 110-170 , and the pivot axes 26 lie on imaginary extensions of the central sections 29 extending away from the bend 27. Furthermore, the relative positions of the knitting needles 3, the direction of rotation of the combing roller 15 and the arrangement of the card wires 25 are coordinated with each other in a known manner as can be seen from Fig. 2 and is conducive to proper combing of the fibres carried by the working sections into the needle hooks 3b.

Circular knitting machines of the kind described are known* for example, from West German Patents 1 201 509 and 2 115 721, West German Patent Application 2 307 111 and West German Utility Model 82 16 932, which are hereby expressly referred to. Here, the card wires 25 may comprise only one arm passing through the intermediate layer and/or be joined to the substrate layer 24 in some way other than described (US Patent 944031). It is therefore appropriate to regard each individual arm as a separate card wire which is independent of any second arm.

The working sections of the card wires 25 protruding from the intermediate layer 24 are normally engaged at a transfer point 30 (Fig. 1-) with corresponding card wires of the card clothing 12 of the opening roller 11, in order to take over at least partially the fibres supplied by the opening roller 11 when the latter and the combing roller 15 are turned together during operation. These fibres are then inserted in the hooks 3b of the knitting needles 3 selected to receive fibres, wherein the needle hooks 3b according to Fig. 2 are located approximately at the level of the bends 27 of the card wires 25.

According to the invention, the card clothing 16 as in Fig.

2 does not comprise the card wires 25, but card wires 32. These are, like card wires 25, joined to the substrate layer 23 in a known manner and comprise, on or in the latter, pivot axes 33 from which extend one or two supporting sections 34 which are e.g. rectilinear as usual, traverse the intermediate layer 24, are elastically supported in the latter and merge into working sections 35 protruding from the intermediate layer 24.

By contrast with the known card wires 25, these working sections 35 comprise at least two bends 36 and 37 each, operation of the first bend 36 being essentially the same as that of the known bend 27. The first bend 36 connects an outer end section 38 of the associated working section 35, to a rectilinear enthral section 39 thereof, while the second bend 37 connects the central section 39 to the end of the supporting section 34 which protrudes out of the intermediate layer 24. The bends 36 and 37 are preferably located in-planes which intersect perpendicularly with the axis of rotation 17 of the combing roller 15.

The length of the working sections 35 measured in a radial direction is appropriately selected so that the radius R1 of the combing roller 15 measured over the outer tips of the card wires 32 is essentially exactly the same as with conventional combing rollers. The same applies to the radius measured up to the outer surface of the intermediate layer 24. As can furthermore be seen from Fig. 2, the bends 36 as seen in the direction of rotation of arrow v, like the bends 27, open forwardly, wherein the angle formed by the end sections 38 and the central sections 39 may, as with ordinary combing rollers, comprise e.g. 110-170 .

The second bends 37, on the other hand, are angled in the opposite direction and hence open in the direction opposite arrow v.

The advantages obtained by the invention are shown below with reference to Figs. 3 and 4, in each of which a central part of the intermediate layer 24 has been omitted to simplify description Fig. 3 shows firstly, schematically and greatly simplified, a card wire 25 of'conventional shape shown in dot-dash lines, which is rotatable about the pivot axis 26. The position of the 'known bend of this card wire 25 is marked by a point 27a in Fig. 3. If during impingement on a knitting needle 3 a force is applied to this card wire 25, a card wire of the opening roller or the like approximately in the direction of arrow w, then the bend moves essentially along an arc 43-until, after a pivot angle ss, it reaches a point marked with the reference number 27b.

Thus its vertical distance from the intermediate layer 24 is reduced by an amount hl, while at the same time its portion protruding from the outer surface of the intermediate layer 24 covers a distance marked by points A and B if pivoting is completely absorbed by recoil of the intermediate layer 24.

Fig. 3 moreover shows schematically a card wire 32 in solid lines according to the invention, which is originally -arranged in such a way that its first bend and its end section 38 corresp-ond to those of card wire 25 (point 36a). If this card wire 32 is now pivoted by its supporting section, which is arranged in the intermediate layer 24, through a corresponding angle ss into a position shown in dashed lines 36b, then the first bend 36 follows approximately an arc 44 until position 36b is reached, as the card wire 32 pivots about its pivot axis 33. It follows that with the same pivot angle ss the vertical distance from the bend 36 to the intermediate layer 24 is reduced only by amount h2, while at the same time its portion protruding from the outer surface of the intermediate layer covers only a distance marked by points C and D. It can be concluded from this that when the card wires 32 according to the invention are used, firstly lower stresses have to be absorbed by the intermediate layer 24, where-by the risk of cracking or softening or slackening of the sponge or foam rubber is counteracted. Secondly, the risk that the distance between the bends 36 and the intermediate layer 24 and hence the radius of the combing roller measured over the outer ends of the card wires 32 will change substantially in the course of time is substantially reduced in comparison with conventional card wires, as amount h2 is considerably lower than amount hl.A decrease in spacing or radius of this kind could in fact occur in particular if the sponge or foam rubber of the intermediate layer 24 slackens or no longer develops the full recovery force, and thus result in different relative positions of the bends of the card wires to the needle hooks 3b, particularly in case of different speeds of the combing rollers. This in turn could lead to unevenness during combing of the fibres into the needle hooks 3b, even if the aforementioned changes in spacing hl with conventional card wires should be within the range of only a few millimetres, which is to a large extent avoided by using the card wires 32 according to the invention.

Another advantageous effect of the card wires 32 according to the invention is apparent from Fig. 4 in which is shown schematically by an arrow x approximately the direction in which a force is applied to the card wires 25 and 32 when they impinge on the card clothing 12 of an opening roller. As the known card wires 25 and the card wires 32 according to the invention pivot about different pivot axes 26 and 33, the result is very different lever arms kl and k2 indicated by dot-dash lines. As lever arm kl for the known card wires 25 is very much larger than lever arm k2 for the card wires 32 according to the invention, the torques applied to the card wires also differ accordingly.

It also follows that when the card wires 32 according to the invention are used, the intermediate layer 24 is subjected to far less stress and therefore has a longer life under otherwise identical conditions. Apart from this, the card wires 32 themselves are subjected to far less bending stress than card wires 25.

The shape of the card wires 32 according to the invention which can be used in particular cases is variable within wide limits. As far as possible, the starting point should be an optimum arrangement and alignment of the first bend 36 and of the end and central sections 38 and 39 which form it, the minimum length and the direction of the central sections 39 being essentially fixed. As shown in particular by Fig. 3, with the known card wires 25 their pivot axis 26 is located in an imaginary and real rearward extension of the central sections 29,extending away from the bend 27. By contrast, the second bend 37 achieves the result that the pivot axes 33 of the card wires 32 according to the invention, as seen in the direction of rotation of the combing roller (arrow v), are located behind such imaginary extensions of the central sections 39 extending in the direction of the pivot axes 26.On the contrary, pivot axes 33 are located between pivot axes 26 and points 45 which are obtained by imaginary rearward extensions of the end sections 38 extending beyond the bend 36 as far as the rear side of the substrate layer 23, as indicated by a dotted line 46 in Fig. 3. The optimum position of the pivot points between the pivot axes 26 and points 45 can be found experimentally, depending on the particular case.However, it proved advantageous if pivot axes 33 are located within ranges which are obtained by central projection of the end sections 38 onto the cylindrical wall surface of the combing roller* wherein the central point is located on the axis of rotation 17 of the combing roller and the projection lines extend perpendicularly or radially to this axis of rotation in planes which contain the central point and are arranged perpendicularly to the axis of rotation 17, as shown by a line R2 in Fig. 3.In this case a compromise must always be found between the two aims - firstly that of obtaining a value of h2 as low as possible, and secondly that of avoiding excessively hard impacts between the end sections 38 and the needle hooks 3b or the 'card wires of the opening roller 11, if any, as might be the case if the pivot axes are arranged at points 45.

The invention is not limited to the practical examples described, which can be modified in many ways. This applies* for example, to the shape and length of the central sections 39 and of the supporting sections 34, which do not absolutely have to be rectilinear. Moreover, the second bend 37 does not need to form a sharp angle, but may extend e.g. along an arc which extends practically over all the portions of the card wires 32 located between the first bends 36 and the pivot axes 33 (Fig. 2), so that the central sections and supporting sections merge into each other.

Also conceivable is the use of more than two bends if the desired shifting of the pivot axes 33 of the card wires is obtained as a result.

Furthermore, the invention is not limited to rectilinear central and supporting sections 34, 39, although such sections are preferred because they are easier to manufacture. Moreover it is not necessary for the central sections 39 to be arranged exclusively outside the intermediate layer 24, as for example the bends 37 can be moved to the intermediate layer 24. The arrangement which can be seen in Figs. 2 to 4, in which the second bends 37 are arranged approximately at the level of the outer surface of the intermediate layer 24, proved to be particularly advantageous, however. Furthermore, it would be conceivable to provide an additional layer between the cylindrical wall surface 22 and the substrate layer 23.

Although the invention has been described with reference to a combing roller, it can also be used to advantage for other rollers used to supply fibres. This is true of, for example, the opening roller 11 and the feed roller 14 according to Fig. 1.

Claims (6)

Claims

1. Roller with card clothing, a cylindrical wall surface and a definite direction of rotation for a knitting machine for the production of knitted goods with combed fibres, the card clothing consisting of a substrate layer facing towards the cylindrical wall surface, an intermediate layer disposed on the outer surface of the substrate layer, and a plurality of card wires which each comprise a supporting section extending through the intermediate layer, a working section extending outwardly out of the intermediate layer and consisting of a central section, an outer end section and a first bend connecting the two, and a mounting section which extends out of the intermediate layer into the substrate layer and which is joined to the substrate layer so as to be pivotable about a pivot axis, characterised in that the portions of the card wires (32) located between the first bends (36) and the pivot axes (33) are shaped in such a way that the pivot axes (33) are located in regions which, as seen in the definite direction of rotation (arrow v), are disposed behind imaginary extensions of the central sections (39) pointing away from the first bend (36).

2. Roller according to claim 1, characterised in that the card wires (32) comprise, between the first bend (36) and the pivot axis (33), at least one second bend (37) which is bent in the opposite direction to the first bend (36).

3. Roller according to claim 2, characterised in that the pivot axes (33) are arranged within regions which are formed by the imaginary extensions of the central sections (39) and corresponding extensions (46) of the end sections (38).

4. Roller according to claim 2 or 3, characterised in that the pivot axes (33) are arranged within regions which are formed by central projection of their end sections (38) onto the cylindrical wall surface (22), wherein the central point is located on the axis of rotation (17) and the projection lines extend in a plane which contains the central point and is arranged perpendicularly to the axis of rotation (17).

5. Roller according to any of claims 1 to 4, characterised in that it is constructed as a combing roller (15).

6. A knitting machine roller having a cylindrical surface and a card clothing comprising a substrate layer surrounding the cylindrical surface, an intermediate layer disposed on the outer surface of the substrate layer, and a plurality of card wires each having a supporting section extending through the intermediate layer, a mounting section which is joined to the substrate layer so as to be swingable about a pivot axis, and a working section extending outwardly of the intermediate layer and consisting of a central sectidn, an outer end section and a first blend connecting the two such that the outer end section is inclined in the direction of travel of the roller surface with respect to the central section, characterized in that the portions of each card wire between the first bend and the pivot axis are so shaped that the pivot axis is displaced in a direction opposite to the direction of travel of the roller surface to lie behind the imaginery extension away from the first bend of the central section of the card wire.