TWIN CARD

Abstract: A twin card having a first carding unit (101) arranged to receive material from a fibrous feedstock material supply means (103, 104, 105) and which delivers partly carded material to a second carding unit (102) via a doffer (109) of the first carding unit and a taker-in (111) of the second carding unit, in which: (a) the first and second carding units (101, 102) are relatively movable between an operative position in which they can co-operate with one another to carry out successive carding operations, and an inoperative position in which an access gap is defined between the units to allow maintenance/cleaning operations to be carried out; and, (b) the transfer means to transfer partly carded fibres from a first carding cylinder (107) of the first carding unit (101) to a second carding cylinder (110) of the second carding unit (102) is constituted by the doffer (109) and the second taker-in (111), thereby excluding a usual train of transfer rollers between the two units (101, 102).

Description: TWIN CARD This invention relates to a twin card which comprises a first carding cylinder arranged to carry out a first carding action on a supply of raw fibres fed thereto, and a second carding cylinder arranged to receive the treated fibres issuing from the first carding cylinder in order to carry out a further carding action and thereby improve the treatment of the fibres. Tandem cards have been used for a number of years, and one commercially successful example is the Mark 5 tandem card supplied by Crosrol Limited of Halifax, United Kingdom. Clearly, the provision of two separate carding cylinders (as opposed to use of a single carding cylinder type of card) means that additional carding action can be obtained, so as to improve the orientation of the fibres and to improve the cleaning efficiency of the operation i.e. to increase the proportion of waste which is removed while minimising the removal at the same time of useful (usable) fibres. The Crosrol Mark 5 tandem card is shown in figure 1 of the accompanying drawings, and will be described, to form a background to the present invention. The tandem card is in two successive sections, in which an upstream card unit, known as the "breaker card" is provided, and is designated generally by reference 10, and which receives a raw material supply of fibres from chute feed 11 , and carries out a preliminary carding operation on the fibres, and then delivers these fibres to the downstream card unit, referred to as the "finisher card" designated by reference 12, and which carries out further carding action, prior to discharge of the treated web of fibres to further treatment machines (not shown). The breaker card 10 comprises a first carding cylinder 13 to which the fibrous raw material is fed from the chute feed 11 via feed device 14 and taker-in 15, and the web of fibres carried by the cylinder 13 then undergo a carding operation in co-operation with a set of movable flats 16, and the treated fibres are then removed by doffer 17, to be transferred to second carding cylinder 18 of the finisher card 12, via a set of transfer rollers 19 (and crusher rollers), and taker-in 20. Second carding cylinder 18 then co-operates with a set of movable flats 21 , and the finally treated fibres are then removed from the cylinder 18 via doffer 22, and then discharged via a web belt unit 23 to further treatment machines (not shown) . It has been accepted practice m the art of carding machines for cotton (and like fibrous material), when using a twin card, that a substantial tram of transfer / crusher rollers is required to transfer the part-carded fibres from the upstream carding cylinder to the downstream carding cylinder. It is for this reason, therefore, that twin cards of the type shown m Figure 1 have provided a substantial number of fibre-handling rollers in the space between the upstream and downstream carding cylinders, and conventional wisdom would indicate that any reduction in the number of rollers in this region would have an unacceptable effect on the quality of treatment of the fibres, and particularly in reducing the effectiveness of the subsequent carding action of the downstream carding cylinder. The two carding cylinder 13 and 18 of the tandem card are fixedly mounted in relation to each other e.g. by the two units 10 and 12 being bolted together, and with a standard spacing of the taker-m 15 of the first carding cylinder 13 from the supply chute 11. Typical spacing between supply chute 11 and the input 14 to the taker-in 15 is about 14 inches. However, with a tandem card (as with all types of carding machines), there is a need for periodic cleaning / maintenance of the components of the machine, and with the close-coupled arrangement between the breaker card unit a d the finisher card unit of a tandem card i.e. the first carding cylinder 13 and its associated components (taker-m, doffei and movable flats), and the second carding cylinder 18 and its related components, it can be difficult to gain adequate access to the components on either side of the interface between the two carding cylinders i.e. the region in which the partly treated fibres are transferred from the first unit to the second unit. Therefore, in one aspect of the invention, it is an objective to provide easy means of relative adjustment of the positions of the two carding cylinders of a twin card (when inoperative) to provide improved access for maintenance / cleaning operations the interface region between the two carding cylinders. Therefore, according to a first aspect of the invention, there is provided a twin card which is intended to apply successive carding operations to a fibrous feedstock material supplied thereto, said card comprising a fibrous feedstock material supply means and first and second carding units, and in which: the first carding unit comprises a first carding cylinder arranged to receive material from said supply means, a first taker-m arranged to transfer the fibrous feedstock from the supply means to the first carding cylinder, and a first set of flats co-operable with the first carding cylinder; and, in which the second carding unit comprises a second carding cylinder, and a second set of flats co-operable with the second carding cylinder; characterised in that the first and second carding units are relatively movable between an operative position in which they can co-operate one with another to carry out successive carding operations on the fibrous feedstock, and an inoperative position in which an access gap is defined between the units to allow maintenance / cleaning operations to be carried out on the components of each unit adjacent to the access gap. A twin card according to the first aspect of the invention therefore can be used to carry out successive carding operations, when adjusted to its operating position, and giving rise to the advantages obtainable with use of first and second carding cylinders, but in the event of routine maintenance or servicing operations being required, e.g. routine cleaning, or even in the event of non-scheduled servicing, it is a simple matter to carry out necessary relative adjustment of the positions of the first and second carding units, to create an access gap between the two units, in which an operator can move into, in order to carry out servicing of adjacent components of each unit. It is not critical as to how the first and second carding units are made to be relatively movable, and both could be movable, or either the first or the second carding unit could be fixed, with the other one being movable. However, in a preferred arrangement, the second carding unit i.e. the downstream unit, is fixedly mounted, whereas the first carding unit is arranged to be movable. Usually, a clearance gap will be defined between the upstream end of the first carding un t and the supply means, to allow proper transfer of the fibrous raw material feedstock from the supply means to the first carding cylinder. Typically, the supply means comprises a feed chute, and means for transferring the feedstock from the chute to the first taker-m may comprise a feed plate and feed roller. The clearance at the upstream end of the first carding unit, typically being about 14 inches, can then be utilised to allow movement of the first carding unit to the inoperative position and away from the second carding unit, by takmg-up this clearance at the upstream end, and thereby creating tne same width of access gap between the two units. Any suitable transfer means may be provided in order to transfer treated fibres from the first carding cylinder to the second carding cylinder, and in a preferred arrangement comprises a direct transfer between a first doffer associated with the first carding cylinder, and a second taker-in associated with the second carding cylinder. Therefore, in a preferred arrangement of the first aspect of the invention, the first and second carding units may take- up approximately the same floor area as known fixed installations of tandem cards (having the same upstream spacing between the feed chute and the taker-m of the first carding unit, when in the operative position), but utilising the upstream clearance gap which is already present to allow necessary relative movement of the first carding unit when adjusted to the inoperative position, so that cleaning or maintenance operations can take place. Evidently, creating an access gap between the two units greatly simplifies access to the component parts of the carding units which require cleaning and / or maintenance. In a preferred arrangement, the first carding unit is mounted on rails, which are able to guide necessary linear movement of the first carding unit between the operative and inoperative positions; and to provide necessary lateral restraint during movement, at least one rail may have engagement with a flanged wheel supporting the first carding unit. The other rail then can have a simple vertical supporting engagement with associated wheel or wheels at the other side of the unit. Any suitable power operated device may be provided m order to carry out necessary linear reciprocation of the first carding unit between the operative and inoperative positions. By way of example only, a hydraulic or pneumatically operated piston / cylinder device may be provided. The first aspect of the invention is primarily concerned with providing relative adjustment movement between first and second carding units of a tandem card, and preferred embodiment of the first aspect provides direct transfer of treated fibres from the first carding unit to the second carding unit via the doffer of the first unit and the taker-m of the second unit. However, according to a second aspect of the invention, the feature of relative movement between the first and second carding units may be omitted, but having the feature of direct transfer of the treated fibrous feedstock from the first carding cylinder to the second carding cylinder via direct contact between the doffer associated with the first carding cylinder and the taker-in associated with the second carding cylinder. It has been found that this gives surprising technical improvements in the hand] ing and the treatment of the fibrous feedstock. Accordingly, in a second aspect of the invention, there is provided a twin card which is intended to apply successive carding operations to a fibrous feedstock material supplied thereto, said card comprising: a fibrous feedstock material supply means; a first carding cylinder airanged to receive material from said supply means; a first taker-m arranged to transfer the fibrous feedstock from the supply means to the first carding cylinder; a first set of flats co-operable with the first carding cylinder; a first doffer arranged to remove treated fibres from the first carding cylinder; a second carding cylinder; a taker-m arranged to transfer treated fibres from the first carding cylinder to the second carding cylinder; a second set of flats co-operable with said second carding cylinder; and, transfer means for removing treated fibres from the second carding cylinder: characterised m that the doffer associated with the first carding cylinder is arranged to transfer the treated fibres directly to the second taker-in associated with the second carding cylinder. A twin card according to the second aspect of the invention is surprisingly effective m the treatment of a fibrous feedstock, m that the deliberate exclusion of substantial tram of rollers to transfer the partly-carded fibres from the first carding cylinder to the second carding cylinder (as in known twin cards) does not in practice result in production of unacceptable sliver, at least in the sense that fabric ultimately formed from yarn derived from the sliver has been shown in tests to have improved quality. The reasons why this unexpected result is achieved is not entirely clear, but it is believed may be due to one, or both of the following theoretical considerations: 1. The presence of a number of transfer and other rollers in known twin cards creates a drafting effect which tends to increase the parallelisation of the partly-carded fibres before they are transferred to the second carding cylinder; 2. The action of the rollers in known twin cards tends to cause the fibres to curl up before they are transferred to the second carding cylinder. At this stage, these theoretical considerations are speculation only, but are given as a possible explanation of why the carding performance of a twin card according to the second aspect of the invention is not inferior to that of known twin cards, but on the contrary can be at least as effective, if not more so, in providing improved production of carded fibres for subsequent formation into sliver, and then fabrication into cloth. Thus, while further parallelisation of fibres before passage to the second carding cylinder might be thought to be a desirable attribute, it is believed that in known twin cards this may actually reduce the effectiveness of the cleaning action exerted on the fibres by the subsequent co-operation between the flats and the second carding cylinder, in that the presentation of non-parallel fibres to the flats of the second carding cylinder may actually enhance the cleaning action. Alternatively, or additional] y, in known twin cards a tendency for curling-up of the fibres, before transfer to the second carding cylinder, may result in less efficient treatment, and cleaning of the fibres between the flats and the second carding cylinder. A preferred embodiment of twin card according to the first or second aspect of the invention will now be described in detail, by way of example only, with reference to Figures 2, 2a and 2b of the accompanying drawings, in which: Figure 2 is a schematic side view illustration of a twin card according to the invention; Figure 2a is a detail view showing part of a linear guidance arrangement for guiding linear reciprocation of one of the carding units of the twin card relative to the other carding unit; and, Figure 2b is a further detail view, similar to Figure 2a, showing a further part of a rail guidance arrangement. Referring first to Figure 2 of the drawings, a twin card according to the invention is designated generally by reference 100, and comprises a first, upstream carding unit 101, and a second, downstream carding unit 102, arranged to apply successive carding operations to a fibrous feedstock material. A fibrous feedstock material supply means is provided, preferably taking the form of a supply chute 103, and which supplies the raw material feedstock to the first carding unit 101 via a usual feed plate 104 and feed roller 105 to a first taker-in 106. The first carding unit 101 has a first main carding cylinder 107 to which the fibrous feedstock is applied by the taker-in 106, and a first set of flats 108 co-operates with the carding cylinder 107 to carry out a preliminary carding treatment of the fibres. In the preferred arrangement, as shown, the first set of flats 108 comprises a set of travelling flats, which will be well known to those of ordinary skill in the art, and which need not be described in detail herein. To remove the treated fibres from the first carding cylinder 107, a first doffer 109 is provided. The second carding unit 102 comprises a second carding cylinder 110, a second taker-in 111, a second set of flats 112, and a second doffer 113. In use, a preliminary carding action is applied to the fibrous material feedstock by the carding components of the first carding unit 101, and the partly treated fibres are then transferred to the second carding unit 102, to receive further carding treatment. The first and second carding units 101, 102 will normally be adjusted to a fixed position, one relative to the other, so that continuous flow of fibrous material can take place between the upstream and downstream ends of the tandem card, and usually there will be a clearance gap G1 between the feed chute 103 and the feed roller 105, which in typical fixed tandem card arrangements is about 14 inches wide. However, at the interface region between the downstream end of the first carding unit 101 and the upstream end of the downstream carding unit 102, there is an adjustable clearance gap G2. This determines the clearance between the first doffer 109 and the second taker-m 111, and can be adjusted by varying the engagement between a fixed stop on one of the units, and an adjustable stop on the other of the units. In the illustrated arrangement, a fixed stop 114 is provided on the second carding unit 102, and the adjustable stop 115 is provided on the first carding unit 101. Adjustment of the adjustable stop 115 can vary the width of the setting or clearance gap G2 between the doffer 109 and the taker-in 111. However, in order to provide an access gap between the first and second carding units, to allow routine or non- scheduled cleaning / maintenance operations to take place, the first and second carding units 101 and 102 are arranged to be relatively movable between an operative position, as shown, and an inoperative position in which an access gap is defined between the two units. In the preferred arrangement, as shown, the second carding unit 102 is fixed, whereas the first carding unit 101 is movable linearly on a guidance system, comprising a pair of spaced rails 120 on which support wheels can run, and which support the first carding unit 101. Figure 2a shows a flanged wheel engagement with a rail, to provide lateral guidance, whereas Figure 2b shows a plain vertical support only . In order to move the first carding unit 101 between the operative and inoperative positions, a suitable power operated device is provided, and which is shown schematically only by provision of a piston and cylinder device (pneumatically or hydraulically operated), and designated by reference 116. Movement of the first carding unit 101 to the right can take-up the standard clearance G1 , and this then increases the clearance gap G2 by the same amount, so as to provide clear access between the two units for an operator to move into this area and carry out routine or other maintenance and cleaning operations. After completion of servicing / cleaning, the first carding unit 101 then returns to the previous clearance setting determined by engagement between fixed stop 114 and adjustable stop 115, i.e. the piston cylinder device 116 operates until such time as they re-engage, and with the assurance that the previous setting has been taken-up again. A tandem card as shown schematically in Figure 2 therefore can take-up generally the same floor area as a conventional design of tandem card having fixedly mounted first and second carding units, and the access gap is created by taking-up space which will be present anyway i.e. the space between the feed chute and the feed roller. The relative adjustment between the first and second carding units, as described and shown schematically, comprises one example only of a first aspect of the invention. In a second aspect of the invention, the feature of relative adjustment may be omitted, or provided as required. According to the example of the second aspect of the invention, there is direct transfer of fibres from the first carding unit to the second carding unit via direct transfer between doffer 109 and taker-in 111. This direct transfer of fibres is different from the train of transfer rollers e.g. as per the known Crosrol mark 5 tandem card shown in Figure 1 , and provides surprising technical advantage in the treatment of the fibrous feedstock. Comparative tests have been carried out, using different samples of cotton fibrous feedstock, using the mark 5 tandem card, compared with the new design of twin card according to the invention as shown schematically in Figure 2, in which there is direct transfer between the doffer and the taker-in. It should be understood that these are preliminary tests only, and that further investigations may be made in the future, possibly giving rise to different results. However, even from these preliminary tests, it is clear that, in at least some circumstances, there are significant technical advantages to be derived in the treatment of fibrous feedstocks, using the preferred embodiment of the invention. The twin card trials were conducted using three different origins of cotton, with differing characteristics. The Turkish cotton was a short staple very trashy cotton, the CIS cotton was a medium staple, relatively clean cotton and the Australian cotton was a longer staple clean cotton. Initial trials were carried out on the existing mark 5 tandem card, before converting it to the twin card of the invention; this ensured that the wire conditions and settings were the same. Three card production rates used were - 65kgs/hr, 85kgs/hr and 105kgs/hr. After two passages of drawframe the samples were spun into ring and rotor spun yarns, prior to knitting. The linear density of the yarns were 12s rotor spun yarn and 16s ring spun yarn, and for the finer yarns the counts were 38s rotor spun yarn and 34s ring spun. The finer counts were not always suited to the type of cottons being spun, but in spinning finer counts, any small imperfections will be more visible rather than being disguised by the body of the yarn. The rotor spun yarn results showed the twin card was equal to or better than the tandem. The twin card ring spun results would have been better than the tandem had the Uster tester not counted trash particles as neps . It is accepted that there is more trash in the twin carded yarns; this problem will be eliminated when the cylinders are fitted with new wires and the speeds optimised. It was in single jersey knitted fabric form that the real advantages of the twin card could be seen. The most critical yarns spun were the 34s Nee ring spun yarns, these were the fabrics that would show up any major differences. Viewing the fabric on blackboard, the twin card fabric had an overall better cover, in that less of the black background could be seen through the interspaces in the yarns. The complete fabrics appeared significantly more regular and less patchy than the tandem fabrics. The tandem fabrics surface appeared to have a more "worn in" (meaning it looked more worn and abraded - can be seen as patches of surface hairs) effect than the twin card fabric. This worn in effect usually signifies that a fabric will be more prone to pilling. Viewing the whiteboards the twin card yarns were generally more trashy but as explained earlier this problem can be resolved. The fabrics spun from the fine count rotor spun yarns showed that the twin card fabrics were substantially better or at least equal to the tandem carded fabrics this was depending upon the type of cotton and its suitability to fine count rotor spinning. Trash levels in the fabrics were either the same or slightly worse off the twin card. The twin card fabrics from the 16s ring spun yarns were as good as, or in some cases substantially better than the tandem fabrics in terms of regularity, and cover. Trash levels in the fabrics from the tandem were either equal to or marginally better than the twin card. The coarse rotor spun fabrics were the least critical of all the fabrics produced, here it was difficult to differentiate between the twin card and the tandem samples both sets looked to be of a good quality. Note: Assessment of the visual appearance of fabrics in a non-quantifiable grading system, there is no measuring apparatus capable of defining and classing fabric appearance. The judgement of fabric appearance is dependant upon the trained eye, but it is a non-quantifiable measure that is relied upon to judge quality by all the major names in the clothing and cloth retail manufacturing industry. In the above description, with reference to Figure 2 of the drawings, there is disclosure of a doffer H and taker-in E, each of which is provided on a separate carding frame sub- assembly, with the sub-assemblies being movable one relative to the other . However, if required, a transfer roller may be located between doffer H and taker-in E, which can give rise to improved quality of carded product. This is achieved with desirably little, or negative drafting effect between the two carding units.

Claims: CLAIMS 1. A twin card (100) which is intended to apply successive carding operations to a fibrous feedstock material supplied thereto, said card comprising a fibrous feedstock material supply means (103, 104, 105) and first and second carding units (101, 102), and in which: the first carding unit (101) comprises a first carding cylinder (107) arranged to receive material from said supply means, a first taker-in (106) arranged to transfer the fibrous feedstock from the supply means to the first carding cylinder (107), and a first set of flats (108) co-operable with the first carding cylinder (107); and, in which the second carding unit (102) comprises a second carding cylinder (110) and a second set of flats (112) co- operable with the second carding cylinder (110); characterised in that the first and second carding units (101, 102) are relatively movable between an operative position in which they can co-operate one with another to carry out successive carding operations on the fibrous feedstock, and an inoperative position in which an access gap is defined between the units (101, 102) to allow maintenance / cleaning operations to be carried out on the components of each unit adjacent to the access gap. 2. A twin card according to claim 1, in which the first and second carding units (101, 102) are both movable. 3. A twin card according to claim 1, in which one of the carding units (101, 102) is fixed, and the other one is movable . 4. A twin card according to claim 3, in which the second carding unit (102) is fixedly mounted, and the first carding unit (101) is arranged to be movable. 5. A twin card according to claim 4, in which a clearance gap G1 is defined between the upstream end of the first carding unit (101) and the supply means (103), to allow transfer of the fibrous raw material feedstock from the supply means to the first carding cylinder (107), and in which the first carding unit (101) is movable to the inoperative position by takmg-up the space taken by the clearance gap G1 , thereby creating the same width of access gap G2 between the two carding units (101, 102). 6. A twin card according to any one of claims 1 to 5 , in which transfer means to transfer treated fibres from the first carding cylinder (107) to the second carding cylinder (110) comprises a first doffer (109) associated with the first carding cylinder (107), and a second taker-m (111) associated with the second carding cylinder (110). 7. A twin card according to claim 4 or 5 , in which the first carding unit (101) is mounted on rails, which are able to guide necessary linear movement of the first carding unit (101) between the operative and inoperative positions. 8. A twin card according to claim 7, including a power operated device (116) for carrying out necessary linear reciprocation of the first carding unit (101) between the operative position and the inoperative position. 9. A twin card which is intended to apply successive carding operations to a fibrous feedstock material supplied thereto, said card comprises: a fibrous feedstock material supply means (103, 104, 105); a first carding cylinder (107) arranged to receive material from said supply means; a first taker-in (106) arranged to transfer the fibrous feedstock from the supply means to the first carding cylinder; a first set of flats (108) co-operable with the first carding cylinder (107); a first doffer (109) arranged to remove treated fibres from the first carding cylinder (107); a second carding cylinder (110); a taker-m (111 ) arranged to transfer treated fibres from the first carding cylinder (107) to the second carding cylinder (110); a second set of flats (112) co-operable with said second carding cylinder (110); and, transfer means (113) for removing treated fibres from the second carding cylinder (110): characterised in that the doffer (109) associated with the first carding cylinder (107) is arranged to transfer the treated fibres directly to the second taker-in (111) associated with the second carding cylinder (110). 10. A twin card according to claim 9, in which a transfer roller is located between the doffer (109) and the second taker-in (111). 11. A twin carding according to claim 9 or 10, in which the first set of flats (108) comprises a set of movable flats, and the second set of flats (112) associated with the second carding cylinder (110) also comprises a set of movable flats. 12. A twin card according to any one of claims 9 to 11, in which the first and second carding units (101, 102) are relatively movable between an operative position in which they can co-operate one with another to carry out successive carding operations on the fibrous feedstock, and an inoperative position in which an access gap is defined between the units to allow maintenance / cleaning operations to be carried out on the components of each unit adjacent to the access gap.

Inventors: VARGA JOHN MAXIMILIAN JULES, VARGA, JOHN, MAXIMILIAN, JULES
Applicants: CARDING SPEC CANADA, VARGA JOHN MAXIMILIAN JULES, CARDING SPECIALISTS (CANADA) LIMITED, VARGA, JOHN, MAXIMILIAN, JULES
Application year: 1998
Main classification: D01G15
IPC codes: D01G15