WO2011080611A1

WO2011080611A1 - Draft device of a drafting machine or a lap - forming machine

Info

Publication number: WO2011080611A1
Application number: PCT/IB2010/055373
Authority: WO
Inventors: Girolamo Prandini; Roberto Torcoli
Original assignee: Marzoli Combing & Flyer S.P.A.
Priority date: 2009-12-28
Filing date: 2010-11-23
Publication date: 2011-07-07
Also published as: BR112012015915B1; CN102695826B; ITBS20090237A1; IT1397140B1; BR112012015915A2; CN102695826A; EP2519666B1; EP2519666A1

Abstract

A draft device (1) of a drafting machine or lap-forming machine on a spinning line comprises an opening unit (10) positioned upline of the draft unit (2). The opening unit (2) comprises opening cylinders with annular bosses or pairs of overlapping cylinders with a cylindrical helix, suitable to sink into each sliver entering the unit to open it, improving the conditions for subsequent drafting.

Description

DESCRIPTION

DRAFT DEVICE OF A DRAFTING MACHINE OR A LAP - FORMING MACHINE

[0001] The present invention relates to a draft device of a drafting machine or lap-forming machine on a spinning line for processing fibre and obtaining a yarn.

[0002] A textile plant for transforming fibre flocks into yarn is composed of numerous machines, which clean the fibres and position them in parallel to obtain fibre webs and finally the yarn.

[0003] The plant usually comprises a plurality of cans in which a sliver of fibre is contained, coming from carding machines, and a lap-forming machine, in which the individual slivers are joined, drafted and overlapped, forming a web, wound to form a lap.

[0004] One embodiment of a production line with cans and lap-forming machine is described in the document EP-A1- 1464739 in the Applicant's name.

[0005] Usually, the process also comprises a drafting machine in which the slivers are drafted only before moving on for subsequent processing.

[0006] Drafting is in both cases performed by a draft device .

[0007] The aim of the present invention is to make a draft device which increases the efficacy of the drafting. [0008] Such purpose is achieved by a draft device made according to claim 1.

[0009] The characteristics and advantages of the draft device according to the present invention will be evident from the description below, offered by way of a non- limiting example, with reference to the appended figures, in which:

[0010] - figure 1 is a schematic side view of a draft device according to the present invention;

[0011] - figure la schematically shows the action of an opening unit according to the present invention;

[0012] - figure 2 shows an axonometric view of the draft device in figure 1;

[0013] - figure 3 shows an opening unit of the draft device according to the present invention, according to one embodiment;

[0014] - figure 4 shows a schematic side view of a draft device according to a further embodiment of the present invention;

[0015] - figure 4a shows an opening unit of the draft device in figure 4;

[0016] - figures 5, 6, and 7 shows further embodiments of an opening unit according to the present invention.

[0017] With reference to the appended drawings, reference numeral 1 globally denotes a draft device, such as a drafting machine or lap-forming machine, fed with a plurality of slivers S.

[0018] The draft device comprises a draft unit 2 able to draft the slivers S.

[0019] The draft unit 2 comprises at least two pairs of drafting cylinders, positioned one downline of the other, having different peripheral speeds, and in particular such that the peripheral speed of the downline pair is greater than the peripheral speed of the upline pair. The sliver S, passing between the pairs of drafting cylinders, is drafted thanks to the difference in the peripheral speeds. The ratio of the peripheral speed of the downline pair of drafting cylinders to the peripheral speed of the upline pair of drafting cylinders is defined "draft". Increasing draft values correspond to a more energetic draft action, that is to say increased lengthening of the sliver.

[0020] According to the embodiment shown, the draft unit 2 comprises:

[0021] - a first pair of drafting cylinders 4, formed of a lower cylinder 4a and an upper pressure cylinder 4b;

[0022] - a second pair of drafting cylinders 6, formed of a lower cylinder 6a and un upper pressure cylinder 6b;

[0023] - a third pair of drafting cylinders 8, formed of a lower cylinder 8a and said upper pressure cylinder 6b, which is therefore common to the second and third pair.

[0024] The draft device 1 further comprise an opening unit 10 positioned upline of the draft unit 2 suitable to open the slivers S before proceeding towards the draft unit 2, by means of opening elements suitable to sink into the individual sliver.

[0025] In other words, the opening unit 10 is suitable to work on slivers S so as to open them, to reduce their compactness, by means of insertion of said opening elements.

[0026] Schematically as shown in figure la, the individual slivers S have an approximately elliptical section and occupy a substantially rectangular area R, when considered all together. By means of the opening unit, the opening elements penetrate the slivers and open them, according to insertion lines L such that each portion has a substantially homogenous density compared to the density of the other portions, between one insertion line and the next.

[0027] According to a preferred embodiment, the opening unit 10 comprises at least one main opening cylinder 12, fitted with a channelled surface 14, so as to forcibly channel the slivers and thereby separate them from other fibres, opening the sliver.

[0028] For example, the cylinder 12, which is rotatable around a rotation axis X transversal to the feed direction of the slivers, has a plurality of circumferential bosses 16 on the surface, in axial succession. A channel 18 is formed between one boss and the next in which the fibres, combined in laps, are channelled.

[0029] The distance between one boss and the next axially abreast boss is defined "pitch".

[0030] The pitch of the bosses of the opening cylinder 12 is preferably less than the average transversal width of the slivers, so that the bosses, which act as the opening elements in such variation, can sink into the fibres of the sliver.

[0031] According to^' the embodiment shown, the bosses are circumferentially continuous.

[0032] According to embodiment variations, the bosses are discontinuous, in other words made as a succession of protruding teeth; according to a further embodiment, the opening elements are defined by a plurality of tips or blades, able to sink into the sliver.

[0033] According to yet a further embodiment the opening elements are positioned axially to form a cylindrical helix, continuous or interrupted in parts.

[0034] According to a preferred embodiment the opening unit 10 comprises a downline opening cylinder 20, for example positioned downline of the main opening cylinder 12.

[0035] The opening cylinders 12, 20 are positioned so that the sliver in transit between the main opening cylinder 12 and the downline opening cylinder 20, follows a downhill circuit; this way the sliver S transits over the top of the main opening cylinder, deviates downwards and transits over the bottom of the downline opening cylinder 20.

[0036] Preferably, downline of the downline opening cylinder 20, the draft device 1 comprises a support bar 30, positioned so that its upper surface, which the sliver S rests on in transit, is substantially at the height of the aperture of the first pair of drafting cylinders 4, and at a greater height than the bottom of the surface of the downline opening cylinder 20.

[0037] In other words, after the downline opening cylinder 20, the sliver follows an uphill circuit, as far . as the support bar 30, to then enter the draft unit 2.

[0038] Advantageously, this makes it possible to create a tension of the moving sliver which pushes it downwards towards the surface of the main opening cylinder 12 and upwards onto the surface of the downline opening cylinder 20, intensifying the channelling effect.

[0039] According to a further embodiment the opening unit 10 comprises an upline opening cylinder 40, positioned upline of the main opening cylinder 12 (figures 4 and 4a) . The upline opening cylinder 40 has structural and functional features similar to those of the main opening cylinder 12.

[0040] According to a preferred embodiment the opening cylinders 12, 20, 40 are non-motorised. According to further embodiments, the opening cylinders 12, 20, 40 are motorised according to yet further embodiments, some opening cylinders are motorised and some are not.

[0041] Advantageously, this makes it possible to regulate the speed of rotation of the cylinders, so as to regulate the speed in relation to the slivers and thereby optimise the channelling action.

[0042] According to one embodiment the opening cylinders are made in lightweight aluminium alloy, so as to reduce rotation inertia.

[0043] According to one embodiment moreover, wherever several opening cylinders are foreseen, the frequency of the opening elements, for example the number of circumferential bosses per unit of length of the relative opening cylinder, increases from high to low. For example, the main opening cylinder 12 has a denser pattern of circumferential bosses along its axis than the upline opening cylinder 40 and the downline opening cylinder 20 has a denser pattern of circumferential bosses along its axis than the main opening cylinder 12

[0044] Advantageously, the progression of the frequency of bosses makes it possible to progressively dose the aggressiveness of the opening effect.

[0045] According to a further embodiment the opening unit comprises overlapping opening cylinders, in other words cylinders the circumferential bosses of which penetrate each other at least partially (figures 5, 6 and 7) .

[0046] In other words, the circumferential bosses of one opening cylinder position themselves inside the ideal cylindrical surface formed by the subsequent bosses of the coupled cylinder, between the valley formed between one boss and the next.

[0047] For example, a co-penetrating cylinder opening unit comprises a lower opening cylinder 12' and an upper opening cylinder 12", for example with the same axial pitch between consecutive circumferential bosses.

[0048] According to a first embodiment the circumferential bosses of one opening cylinder are in phase with the circumferential bosses of the overlapping opening cylinder, so that the top of a boss of one opening cylinder corresponds to the bottom of a valley of the other opening cylinder (figures 5 and 7).

[0049] According to a further embodiment the circumferential bosses of one opening cylinder are out of phase with the circumferential bosses of the overlapping opening cylinder, so that the top of a boss of one opening cylinder corresponds to the sloping side of the other opening cylinder (figure 6) .

[0050] According to yet a further embodiment, the overlapping cylinders have a different pitch.

[0051] According to a further embodiment, the overlapping opening cylinders have opening elements with a cylindrical helical movement, continuous or interrupted in parts, wherein the two helixes have opposite winding directions, so as to balance the axial shift effect on the slivers processed.

[0052] Preferably, moreover, the drafting machine or lap- forming machine comprises a support surface 50, upline of the opening unit 10, inclined downhill in the direction of advancement of the slivers.

[0053] In addition, the drafting machine or lap-forming machine comprises a plurality of deviation elements 52, which occupy a deviation region of the support surface 50, projecting from it, near the entrance rim. The deviation elements 52 are preferably positioned in a herringbone pattern so as to reduce the width of the flanked group of slivers.

[0054] In other words, the deviation elements 52, composed of blocks in a parallelepiped shape with rounded corners, comprise a tip element 52a, positioned substantially in contact with the entrance rim of the surface 50, and side elements 52b, flanking the tip element 52a, which move further away from the entrance rim as they approach the sides of the surface 50.

[0055] The deviation elements 52 are positioned so as to be transversally distanced and form ducts between them which the slivers are channelled into, transversally delimited by said elements 52.

[0056] The drafting machine or lap-forming machine further comprises a substantially horizontal end surface 60, downline of the support surface 50, immediately downline of which the opening unit 10 is positioned.

[0057] According to a preferred embodiment, the drafting machine or lap-forming machine comprises aspiration devices able to aspirate dirt or the like from the slivers as they pass.

[0058] For example, said aspiration devices comprise through slots which go through the thickness of the end surface 60.

[0059] Innovatively, the draft device according to the present invention makes it possible to improve the drafting of the slivers so that these reach the draft unit already opened.

[0060] Accentuated opening of the slivers corresponds to an accentuated opening of the fibres and therefore better adhesion of the same, thereby improving drawing.

[0061] Advantageously, moreover, the uphill and downhill circuit of the slivers makes it possible to intrinsically push the slivers onto the channelling surfaces, accentuating the effect of the opening unit.

[0062] It is clear that a person skilled in the art may make modifications to the draft device described above so as to satisfy contingent requirements.

[0063] For example, in one embodiment variation, the opening elements are fixed.

[0064] All the variations fall within the sphere of protection as defined by the following claims.

Claims

1. Draft device (1) of a drafting machine or lap-forming machine of a spinning line, comprising:

- a draft unit (2) able to draft an incoming sliver;

- an opening unit (10) positioned upline of the draft unit (2), comprising opening elements suitable to sink into each incoming sliver to open it.

2. Device according to claim 1, wherein the opening elements are moveable, for example in rotation.

3. Device according to claim 1 or 2, wherein the opening unit comprises a main opening cylinder (12) fitted with a channelled surface for channelling portions of sliver.

4. Device according to claim 3, wherein the main opening cylinder (12) comprises a number of circumferential bosses (16) which form said opening elements.

5. Device according to claim 5, wherein said bosses (16) are in axial succession to form circumferential channels (18).

6. Device according to claim 5, wherein the circumferential bosses are in axial succession with a predefined pitch less than the average transversal width of the individual slivers (S) .

7. Device according to any of the claims from 3 to 6, wherein the opening unit (12) comprises a downline opening cylinder (20) , positioned downline of the main opening cylinder (12), structurally and functionally similar to it.

8. Device according to claim 7, wherein the top of the lateral surfaces of the main (12) and downline (20) opening cylinders are at different heights, so as to form a downhill circuit of the slivers in the direction of advancement .

9. Device according to any of the claims 7 or 8, wherein the opening unit (10) comprises an upline opening cylinder (40) , positioned upline of the main opening cylinder (12) , structurally and functionally similar to it.

10. Device according to claim 9, wherein the top of the lateral surfaces of the main (12) and upline (40) opening cylinders are at different heights, so as to form an uphill circuit of the slivers in the direction of advancement .

11. Device according to any of the previous claims wherein the opening elements are tips or blades or form a helix, continuous or interrupted in parts.

12. Device according to any of the previous claims when dependent on claim 7, wherein the main opening cylinder (12) has a greater frequency of circular bosses than the downline opening cylinder (20) .

13. Device according to any of the previous claims when dependent on claim 9, wherein the upline opening cylinder (40) has a greater frequency of circular bosses than the main opening cylinder (12) .

14. Device according to any of the claims from 3 to 13, wherein at least one of said opening cylinders is not motorised.

15. Device according to any of the claims from 3 to 14, wherein at least one of said opening cylinders is motorised.

16. Device according to any of the previous claims comprising pairs of overlapping opening cylinders (12', 12'^■ ) .

17. Device according to claim 16, wherein the overlapping opening cylinders (12 ', 12'') have circumferential bosses in phase.

18. Device according to claim 16, wherein the overlapping opening cylinders (12', 12'') have circumferential bosses out of phase.

19. Device according to any of the claims from 16 to 18, wherein the overlapping opening cylinders (12', 12'') have circumferential bosses of a different pitch.

20. Device according to any of the previous claims, when dependent on claim 9, wherein the opening cylinder is made in lightweight aluminium alloy.

21. Device according to any of the claims from 16 to 20, wherein the overlapping opening cylinders comprise opening elements having a helical movement, continuous or interrupted in parts, for example in an opposite winding direction.

22. Draft frame or lap-forming machine comprising a draft device made according to any of the previous claims.