GB2114608A - Circular knitting machine for the production of knitted goods with combed-in fibres - Google Patents

Abstract

For combing-in the machine has a carding device including a carding drum and a doffer roller 37. The roller 37 has a card clothing 39 with card wires 38 which extend over a constant width b so that the zones penetrated by the needles during combing-in always have an equal length. The clothing can be formed by spiral winding of a narrow belt followed by removal of the card wires up to parallel edges 40 which are perpendicular to the axis 42. Preferably the carding drum is also formed with card wires extending over a constant width. <IMAGE>

Description

SPECIFICATION Circular knitting machine for the production of knitted goods with combed-in fibres The invention relates to a circular knitting machine for the production of knitted goods with combed-in fibres, in which, for combing in the fibres, at least one carder is provided, which possesses a supporting belt having a section that is penetrated by the knitting needles and is provided with cards.

Owing to the special problems arising in the use of card wheels in connection with knitting machines for the production of knitted goods with combed-in fibres, flexible card clothing or supporting belts, provided with wire hooks on their outer surface, are wound around these card wheels, the width of these belts being considerably smaller than the width of the card wheels, measured in the direction of the axis of rotation. (German Patent Application P 3,024,962). The supporting belts are spirally passed around the surface area of the card wheels in a larger or smaller number of windings and at a higher or lower gradient, depending on their width and the diameter of the card wheels, and are fastened there by means of screws or by glueing.

Since purely manual wrapping of the card wheels causes difficulties, devices of the type described at the beginning have already been disclosed or proposed, which mechanise and simplify the wrapping of the card wheels. in the application of these devices, the supporting belts are guided by hand or mechanically and simultaneously pressed against the winding that has been previously applied in each case, the use of auxiliary devices enabling the initial gradient to be defined and the tolerance for the width of the supporting belt to be taken into account. It has however not been possible so far, even by applying devices of this kind, to eliminate the problem of irregular formations, caused by uneven fibre distribution, appearing in the finished knitted texture, which considerably impair the quality of the fabric.

The invention is based on the object of avoiding undesired irregular fibre distribution in knitted goods with combed-in fibres and of providing a circular knitting machine for the production of faultless knitted goods with combed-in fibres.

For the solution of this problem, the circular knitting machine, described at the beginning, is characterised in that the section of the supporting belt, containing the cards, has constant width along the entire circumference of the stripping roller.

Further advantageous features of the invention become clear from the subsidiary claims.

The invention implies the surprising discovery that very considerable progress with respect to uniform fibre distribution in the finished knitted texture can be achieved by a relatively simple modification of the card wheels hitherto used in circular knitting machines for the production of knitted goods with combined-in fibres. The assumption had previously been that undesirable lack of uniformity in fibre distribution, particularly periodic spiral patterns, was to be ascribed to the spirai winding of relatively narrow supporting belts around the card wheels. Experiments show, however, that this kind of lack of uniformity can be eliminated by the use of the card wheels according to the invention almost completely or, at least, to such an extent that this lack of uniformity can no longer be detected by the naked eye.This surprising effect is ascribed to the fact that, on using the card wheels according to the invention, each needle, regardless of which range of the card wheel it passes through for the purpose of picking up fibres, it covers invariably exactly the same distance within the carding cloth and therefore picks up invariably the same amount of fibres. The invention is explained in detail in the following in connection with the attached drawing, with reference to exemplary embodiments.

Figure 1 shows a circular knitting machine of known construction; Figures 2 and 3 show card wheels, which are spirally wound around with a carding cloth in a known or already proposed manner; Figure 4 shows a doffer roller according to the invention; Figure 5 shows a carding drum according to the invention; Figure 6 shows a card wheel according to the invention, onto which the card clothing has been drawn by means of a tube: and Figure 7 shows a card wheel according to the invention, around which a card clothing, in the form of an endless belt, has been wound.

According to Fig. 1, a known circular knitting machine for the production of a patterned knitted fabric 1 with combed-in fibres possesses a base plate 2, in which a needle cylinder 5, fitted with knitting needles 3, and a sinker ring 9, fitted with sinkers 7, are rotatably supported. The knitting needles 3 and sinkers 7 are controlled by cams in the usual way, the circumference of the needle cylinder 5 being provided with several spaced knitting systems, each having a pattern device 11, by means of which the knitting needles 3 are selected according to pattern for picking up fibres or not picking up fibres, respectively.

Besides, each knitting system is provided with a carding device 12, which is fastened to a frame 14 and serves for feeding fibres having a certain property, e.g. colour, to the knitting needles selected for picking up fibres.

Each carding device 1 2 consists, for example, of a tambour or carding drum 1 5 having a cord clothing 16, which is fed with fibres in the form of a sliver 1 7 with the aid of a pair of feed rollers 18, and of a doffer roller or combing-in roller 1 9 having a card clothing 21, by means of which the fibres, taken off from the carding drum 15, are offered to the knitting needles 3, selected for picking up fibres. The combing-in point is located at the place where the hooks of the knitting needles 3 pass through the card clothing 21 on a track running essentially parallel to the axis of the doffer roller 1 9.

A drive 23 for the feed rollers 1 8 is controlled with the aid of a control device 25 in such a way that the fibres, averaged for relatively short periods, are transferred from the carding drum 1 5 to the combing-in roller 1 9 in amount such as is required by the pattern.

For evening out the fibre supply present on the doffer roller 19, a homogenising roller 26 can be associated to the latter.

Circular knitting machines of the type described have been disclosed, for example, in West German Patent Specification 1,201,509 and West German Offenlegungschriften (Unexamined Patent Applications) 2,115,721, 2,343,886, 2,524,491 and 2,748,941, to which reference is herewith made explicitly.

Figs. 2 and 3 each show a card wheel 27 with a collar 28. The card wheel 27 is spirally wound around, at an angle of twist a, with a card covering 29, which consists, as usual, of a, for example, textile supporting belt 30 and of card wires or fittings, for example wire hooks 31, which are incorporated into the supporting belt. The position of the start of the supporting belt 30 is fixed by the collar 28 and secured by means of a screw 32, while the position of the end of the supporting belt 30 is secured by a screw 33. The reference signs 34 and 35 denote vacant zones on the surface area of the card wheel 27, which are obtained during the customary winding with a supporting belt 30 of constant width.

Since the wire hooks 31 are uniformly incorporated into the entire surface of the supporting belt 30, the position of the wire hooks 31 on the surface area of the card wheel 27 corresponds exactly to the arrangement of the supporting belt 30. The reference signs 36 in Fig. 2 represent typical corrugations in the course of the windings of the supporting belt 30. These corrugations 36 are a consequence of tolerances in the width of the supporting belt 30 or of lack of uniformity, due to other reasons, in winding and have adverse results for the knitted texture to be produced.

By way of contrast, Fig. 3 shows a card wheel 27, which is wound around with ideal uniformity and is characterised by the virtually corrugation-free course of the windings and a correspondingly uniform arrangement of the wire hooks 31. Windings of this type can be produced with a device described in an earlier Application, P 3, 024, 962, of the same Applicant.

Fig. 4 shows a card wheel 37 according to the invention in the form of a doffer-roller, which can be employed, for example, as the doffer-roller 1 9 according to Fig. 1. The card wheel 37 is wound around with a card clothing 39, having wire hooks 38, the wire hooks 38 being located, however, only on a section of the supporting belt 39, which has a constant width b. The lateral edges 40 of this section are arranged not only parallel to one another, but also parallel to the end faces 41 of the card wheel 37, which, in turn, are arranged in planes running vertically to the axis of rotation 42, indicated by the broken line, of the card wheel 37. Correspondingly, Fig. 5 shows a card wheel 43 according to the invention, in the form of a carding drum, which can be employed, for example, as the carding drum 1 5 according to Fig. 1.The card wheel 43 is provided with a card clothing which has a supporting belt 44, which is provided with wire hooks 45 in a section of a width b that is constant throughout. The lateral edges 46 of the section fitted with the wire hooks 45 are arranged not only parallel to one another, but also parallel to the end faces 47 of the card wheel 43, which, in turn, run parallel to notional planes running vertically to the axis of rotation 48, indicated by the broken line, of the card wheel 43.

As becomes clear from Figs. 4 and 5 moreover, the sections containing the wire hooks 38 or 45 are produced by first winding around the card wheels 37 and 43 in the customary way with a supporting belt 39 or 44, which is narrow in comparison with the width of the card wheel, and fastening the ends of the supporting belts to the card surface by means of screws 49 and 50. In this connection, the procedure can be either according to Fig. 2 or Fig. 3. Subsequently, the wire hooks or fittings, which are denoted in Figs. 4 and 5 by the reference signs 38 and 45, are removed at the outer edges of the supporting belts 39 or 44 in such a way that the lateral edges 40 or 46 of the remaining section of the supporting belt 39 or 44, which is still fitted with wire hooks 38, 45, run along peripheral lines, which lie in planes running vertically to the axes of rotation 42 or 48.

Removal of the excess of wire hooks or fittings 38, 45 can be effected, for example, by grinding down the latter by means of a grinding machine, so that the supporting belts 39 or 44 of these card clothings are positioned in the way that can be seen in Figs. 4 and 5 and remain secured by the screws 49 and 50. Alternatively, it would be possible to fasten the supporting belts 39, 44 to the card wheels 37 or 43 by glueing and then cut them along peripheral lines, running vertically to the axes of rotation 42, 48, in such a way that not only the excess of wire hooks 38 or 45, but also the associated sections of the supporting belts 39 or 44 can be removed.

The method of removing the excess of wire hooks or fittings 38, 45 has no noticeable influence on the quality of the knitted goods produced with the card wheels according to the invention.

A further possibility for the production of the card wheels according to the invention consists in drawing according to Fig. 6 onto a card wheel 55 an or tube 56, which is already provided with a prefabricated section of constant width b, containing wire hooks 57. This measure would have the advantage that, on changing a card clothing, the card wheels have to be dismantled from the circular knitting machine only for a short time. The fastening of the envelopes 56 to the card wheels 55 can be effected by surface shrinking, glueing, screwing or in some other way.

Finally, Fig. 7 shows a further embodiment of the invention, in which wire hooks 58 are formed on an endless supporting belt 59 and the latter is drawn as a whole onto the card wheel. In this case, again, the width b of the section containing the wire hooks 58 is constant and the lateral edges of that section run in planes that are vertically arranged to the axis of rotation of the card wheel.

The advantage that can be obtained with the invention results particularly from the tracks 60 and 61, which are represented in Figs. 4 and 5 by broken lines and indicate the tracks of knitting needles during the passage of the wire hooks 38 or 45. Independently of the position of these tracks on the circumference of the card wheels, the length of these tracks is always the same, as long as the angle between the track and the axis of rotation of the associated card wheel remains unchanged. It may be concluded from this that each knitting needle, passing through the card covering, also picks up essentially the same amount of fibres.

The invention is not limited to the exemplary embodiments described, which may be modified in many ways. For example, it is not necessary for the end faces of the card wheels to run parallel to the lateral edges of the card covering, since the course of these end faces has no influence on the distance passed by the knitting needles within the card clothings.

Furthermore, the lateral edges of the sections containing the wire hooks need not be spaced at exactly the same distances from one another at all points along the circumference of the card wheels, since minor deviations, which do not differ materially from the customary observable tolerances, have only an insignificant influence on the uniformity of the fibre woof (combing in of the fibres).

Furthermore, it is not essential to grind off the wire hooks or cut their supporting belts so that the measure b, shown in Figs. 4 and 5, is smaller than the width of the card wheels.

It is also possible, in fact, first to apply card clothings having a larger width in comparison with the card width and then carry out the cutting or grinding operation so that the measure b is essentially equal to the width of the card wheels.

Furthermore, it is useful to dimension the lengths of the distances 60 or 61, which the knitting needles pass through within the card clothings, particularly by adjusting the speeds of revolution of the card wheels and by dimensioning the width b and the angle between the axes of rotation of the card wheels and the needle tracks in such a way that they are adapted to the maximum amount of fibires that the knitting needles can pick up. It can be avoided, in this way, that excessive amounts of fibres accumulate in the hooks of the knitting needles, drop off without control and adversely affect the fibre distribution in the knitted texture.

Finally, the width b of the sections containing the wire hooks is chosen with particular advantage in such a way that the width of that section is larger for the doffer roller than for the carding drum, but smaller than the distance, along which the knitting needles are located at the combing-in point in their raised position, suited to fibre pick-up. The width of the section of the feed rollers, containing the wire hooks, however, should be smaller than the width of the corresponding section of the carding drum.

Furthermore, it is possible, in modification of the embodiments according to Figs. 4 and 5, not to wind around the surface areas of the card wheels spirally with a relatively long supporting belt, but to cover them with individual strips of the supporting belt, arranged in parallel, the length of the strips corresponding to the length of the surface area. Care should be taken in this case, however, that these strips are arranged so thatt,ke wire hooks are offset to one another in the ttanner customary for carding devices of this,tpe.

Finally, the invention is no! limited to those embodiments, in which the lateral edges of the sections containing the wire hooks are arranged vertically to the card axis. As Figs. 4 and 5 show, in fact, lateral edges that are arranged obliquely to the card axis and parallel to one another also lead to sections of equal width in the sense that the knitting needles, on passing through the wire hooks, always cover tracks 60 or 61 of equal length.

Claims (11)

1. A circular knitting machine for the production of knitted goods with combed-in fibres, comprising for combing-in the fibres, at least one carding device having a doffer roller being provided with a card clothing having a section that is traversed (passed through) by the knitting needles and is provided with card wires, characterized in that said section of the card clothing (39, 44, 59) has constant width (b) along the entire circumference of the doffer roller (37, 43, 55).

2. A circular knitting machine according to claim 1, in which the carding device possesses, in addition, at least one carding drum and a pair of feed rollers, characterized in that at least the carding drum (15) and, preferably, also the feed rollers (18) consist of card wheels (37, 43, 55), which possesses a card clothing having a section that contains card wires (38, 45, 57, 58) and has constant width (b) along the entire circumference of the card wheels (37, 43, 55).

3. A circular knitting machine according to claim 1 or 2, comprising a plurality of carding devices each comprising at least a pair of feed rollers, a carding drum, a doffer roller and, in case of need, additional rollers provided with card clothings, characterized in that all the rollers (15, 18, 19, 28) are designed as card wheels (38, 43, 55), which are provided with a card clothing having a section that contains card wires (38, 45, 57, 58) and has constant width (b) along the entire circumference of the card wheels (38, 43, 55).

4. A circular knitting machine according to at least one of the claims 1 to 3, characterized in that the width of the section having card wires of the doffer roller is greater than the width of the section having card wires of the carding drum, but smaller than the path, along which the knitting needles pass at the combing-in point in their raised position, suitable for picking up fibres, and that the width of the section having card wires of the feed rollers is smaller than the width of the section having card wires of the carding drum.

5. A circular knitting machine according to at least one of claims 1 to 4, characterized in that the lateral edges (40, 46) of the section containing the card wires (38, 45, 57, 58) are arranged in planes running vertically to the axes of rotation of the rollers (42, 48).

6. A circular knitting machine according to at least one of claims 1 to 5, characterized in that the card clothing is fixed to a tube or collar (56) that is pushed onto the roller (55) and is fastened to the latter.

7. A circular knitting machine according to claim 6, characterized in that the card clothing is fastened by shrinking the tube or collar (56) onto the roller (55).

8. A circular knitting machine according to at least one of the claims 1 to 7, characterized in that the card wires (58) are incorporated in an endless belt (59).

9. A circular knitting machine according to at least one of claims 1 to 8, characterized in that the card clothing (39, 44) is spirally wound onto the roller (37, 43) or the tube or collar (56) and the card wires (38, 45, 57) are ground off along a section of constant width.

10. A circular knitting machine according to at least one of claims 1 to 7, characterized in that the card clothing (39, 44) is spirally wound onto the roller (37, 43) or the tube or collar (56) and the coil is cut off to constant width at its lateral edges.

11. A circular knitting machine according to at least one of claims 1 to 10, characterized in that the width of the rollers is greater than the width of the sections containing the card wires (38, 45, 57, 58).