GB2205112A - Machine for producing twistless flax fibre yarn - Google Patents

Abstract

In a machine for producing twistless flax fibre yarn each yarn path includes a drafting system (3) with driven feed (12) and draft (13) rollers, top rollers (25 and 26) and bell cranks (21 and 22) carrying these top rollers (25 and 26). The top rollers (25 and 26) are urged against feed (12) and (13) rollers by a weighting system (27) operatively connected with bell cranks (21 and 22) and with a yarn breakage sensor (7). This provides for eliminating the influence of the varying weighting effort of one top roller upon another top roller. A revolving air jet device (4) and a device (6) for supplying a wetting fluid are also provided. <IMAGE>

Description

MACHINE FOR PRODUCING TWISTLESS FLAX FIBRE YARN" This invention relates to textile machinery intended for the production of flax fibre yarn in a wet spinning process. and more particularly to a machine for producing twistless flax fibre yarn.

There is known a machine for producing twistless flax fibre yarn. comprising, arranged successively in the yarn advance direction from bottom to top along each yarn path, a device for wetting the yarn. a drafting system including feed and draft rollers and top rollers, a pneumatic revolving or twisting tube communicating with a compressed-air line, a yarn breakage sensor and a winding mechanism with a yarn traverser (FR, B, 2096738).

However, in known machines of the this kind the top rollers of the drafting system are paired for two adjacent yarn paths, mounted on a common shaft and weighted by one and the same weight arm. This has been found to impede the operating of the machine, as breakage of yarn in one yarn path, necessitating the withdrawal of the respective top roller. steps up the yarn breakage tendency in the adjoining paired yarn path. Furthermore, with a pair of top rollers being mounted on a common shaft, the yarn quality is impaired, on account of the fact that when thickened or otherwise defective roving runs under one roller, this affects the weighting and causes skewing of the other roller of the adjoining yarn path, so that the draft of the roving in this adjoining yarn path is adversely affected.

The common arms of the top rollers hinder the operation of the machine. making performance of one roller dependent on the other one; moreover, when the yarn or roving of one top roller breaks, either the other roller of the pair or even the entire machine has to be halted, which affects the overall productivity.

There is also a tendency towards dirt and fibres accumulating on the journals of the common shaft, which are difficult to remove. Furthermore, impurities and loose fibres released by the fibrous product also accumulate on the end surfaces of the pneumatic revolving tube, necessitating the arresting of the machine for cleaning the tube.

The main object of the present invention is to create a machine for producing twistless yarn of flax fibre. wherein the load applied to the top rollers of one yarn path is independent of the varying load of the top rollers of the adjoining yarn path.

It is another object of the present invention to provide for the curing yarn breakages in either yarn path without deactivating the adjoining yarn paths.

It is a still further object of the present invention to enhance the yarn quality and the productivity of the machine.

These objects are attained in a machine for producing twistless yarn of flax fibre. wherein along each yarn path there are successively arranged in the yarn advance direction, from top to bottom, a drafting system including driven feed and draft rollers, top rollers engaging the feed and draft rollers and bell cranks. one bell crank having one arm carrying the top roller engaging the feed roller and the other bell crank having one arm carrying the top roller engaging the draft roller; a device for supplying wetting fluid onto the fibre; a pneumatic revolving tube; a compressed-air line communicating with the pneumatic revolving tube: a yarn breakage sensor; a yarn-winding mechanism with a yarn traverser; and a system for weighting the top rollers of the drafting system, operatively connected with the other arn,s of the bell cranks and with the yarn breakage sensor.

The provision of a weighting system for each yarn path eliminates the influence of a varying load applied to the top rollers of adjoining paths. allows the top rollers of each yarn path to withdraw simultaneously from their respective bottom rollers following a signal sent by the yarn breakage sensor, and cures a yarn breakage in either yarn path without halting either the adjoining yarn path, or the machine as a whole.

In a preferred embodiment of the invention, the system for weighting the top rollers of each pair includes an electrically controlled pneumatic valve operatively connected with the yarn breakage sensor and pneumatic chambers. each chamber having a resilient diaphragm operatively connected through a spring-urged rod and a pivoted arm to the arm of the respective bell crank, and its internal space under the diaphragm communicating with the compressed-air line by way of supply pipes and the electrically controlled pneumatic valve.

The bell crank carrying the top roller of the drafting system preferably also supports the pneumatic revolving tube and the device for supplying a wetting fluid, in the form of a tube. This offers better conditions in the service zone and allows the wetting fluid to be supplied directly into the drafting zone, to reduce non-uniformity of the yarn produced.

It is expedient to have nozzles arranged at the level of the end surfaces of the pneumatic revolving tube, communicating with the compressed-air line, so as to avoid accumulation of dirt, fine loose fibres and impurities at the inlet and outlet of the revolving tube, thus providing for maintaining a substantially constant tension of the yarn issuing from the revolving tube.

To avoid oscillating motion of the roving and the yarn. and also to level out their tension and velocity in front of the draft roller and winding mechanism, respectively. it is expedient to have inclined deflecting plates provided to deflect the moving roving or yarn from a vertical path, the plate in front of the winding mechanism being preferably mounted on the yarn traverser and extending at an angle from 50 to 700 to the vertical plane. the plate preferably having projections extending in the direction of the advance of the traverser; and the plate in front of the drafting roller being preferably in the form of a table having its work surface extending at an angle from 5 to 17 to the vertical plane, with an endless apron running about this table and the feed roller.

The invention will be further described in relation to its preferred embodiment, by reference to the accompanying drawings, wherein: Fig. 1 is a schematic general sectional view of a machine embodying the invention for producing twistless flax fibre yarn; Fig. 2 is a longitudinally sectional view of the pneumatic revolving tube of the machine; Fig. 3 shows the traverser with an inclined plate mounted thereon; Fig. 4 illustrates the position of the traverser relative to the driving drum.

The machine for producing twist less flax fibre yarn comprises a plurality of spinning stations, each with its own yarn path, successively arranged and uniformly spaced along the front of the machine. Each yarn path includes, successively arranged in the yarn advance direction, from top to bottom, a package 1 (Fig. 1) with a supply of roving 2. a drafting system 3. a pneumatic revolving tube 4 communicating with a compressed-air line 5 of the machine, a device 6 for supplying a wetting fluid onto the fibre, a yarn breakage sensor 7 of any suitable known structure, and a winding motion or mechanism 8 with a yarn traverser 9.

The supply package 1 is mounted on a support 10 with an underlying trough 11 for collecting the wetting fluid (e.g. water) flowing down from the supply package 1 and drafting system 3. The drafting system 3 includes a driven feed roller 12 and a driven draft roller 13, individually driven in each yarn path of the machine.

the rollers 12 and 13 being supported by a bracket 14 mounted on circular section support bars 15 and 16 with the aid of detachable covers 17 and 18.

The rollers 12 and 13 are individually driven from their respective driving shafts 19 and 20 through driving chains or other flexible endless driving members.

The drafting system 3 in each yarn path includes two bell cranks 21 and 22 swinging about their respective pivots 23 and 24 and carrying each on its one arm the respective rop roller 25 or 26, the top roller 25 being urged against the feed roller 12, and the top roller 26 being urged against the draft roller 13. The other arms of the bell cranks 21 and 22 are operatively connected with a system 27 for weighting the top rollers 25 and 26, provided for each drafting system 3 and operatively connected with is yarn breakage sensor 7.

The weighting system 27 includes an electrically controlled pneumatic valve 28 of any suitable known structure, electrically connected with the yarn breakage sensor 7, and two (for the two bell cranks 21 and 22) penumatic chambers 29 and 30 each having a resilient diaphragm 31 fixed to a rod 32. The rods 32 of the pneumatic chambers 29 and 30 are connected through pivoted arms 33 and spring-loaded rods 34 with the respective other arms of the bell cranks 21 and 22. The internal space 35 of each pneumatic chamber 29 and 30 under its diaphragm 31 communicates with a compressed-air line 36 via respective supply pipes 37 and 38, the electrically controlled pneumatic valve 28 and a T-piece 39.

In operation of the machine. the load for weighting the top rollers 25 and 26 is derived from the compressed-air line 36, through the electrically controlled valve 28 and T-piece 39. With a signal coming from the yarn breakage sensor 7 indicating that no breakage is detected, compressed air is fed simultaneously through the T-piece 39 into the pneumatic chambers 19 and 30. so that the rods 32 fixed to the respective resilient diaphragms 31 act upon the pivoted arms 33, making them turn on their pivots 40 and transmit the effort through the respetive rods 34 to the bell cranks 21 and 22. If the yarn breaks, and the sensor 7 sends a corresponding signal to the electrically controlled valve 28 to cut off the compressed air supply, the respective springs 41 act upon the rods 34 and withdraw the top rollers 25 and 26.

respectively, from the rollers 12 and 13.

The bell crank 22 carrying the top roller 26 further supports a plate 42 on which the device 6 for supplying the wetting fluid and the revolving tube 4 are mounted.

The same plate 42 (Fig. 2) has nozzles 43 and 44 mounted thereon at the respective levels of the end surfaces of the revolving tube 4, to blow impurities, such as lint, loose fibres, and so forth off these surfaces.

compressed air being supplied to these nozzles 43 and 44 via a system of ducts and passages 45-49. The body of the revolving tube 4 has an annular chamber 50 formed therein for directing compressed air via passage 51 extending tangentially with respect to the central bore 52 of the tube 4. Compressed air is supplied to the system 45-49 of the plate 42 from the compressed-air line 5 (Fig. 1) via a pipe 53.

The upper support bars 54 and 55 of the machine have a bracket 56 mounted thereon with the aid of detachable covers, the bracket 56 carrying the winding mechanism 8 including a friction-drive shaft 57, a bobbin holder 58 and the shaft of the traverser 9, carrying a grooved driving drum 59 (Fig. 4) imparting reciprocation to the traverser 9 through a follower block 60.

Mounted in front of the winding mechanism 8 (Fig. 1) and of the draft roller 13 are respective inclined plates 61 and 62.

The plate 61 (Fig. 4) is mounted on the traverser 9 at an angle =50-700 to the vertical plane. The plate 61 has projections 63 (Fig. 3) thereon, extending along the direction of the reciprocation of the traverser 9.

The bottom edge 64 of the plate 61 is bent accurately, as can be seen in Fig. 4, to minimize rubbing wear of the running yarn.

The plate 62 (Fig. 1) has the form of a table with its working surface extending at an angle B-5-170 to the vertical plane. An endless apron 65 runs about the feed roller 12 and the table.

Compressed-air lines 5 and 36 are connected to the spinning shop compressed air supply line.

The machine operates as follows: The roving 2 unwound from its supply package 1 revolving on the support 10 is fed into the nip between the top roller 25 and the apron 65 against which the top roller 25 is urged. so that it is rotated through the apron 65 by the driven feed roller 12. Water dripping from the supply package 1 and from the tube of the wetting fluid supply device 6 is collected in the trough 11.

The driven feed roller 12 is rotated by the driving shaft 19 through the flexible transmission. The endless apron 65 running at the top about the inclined plate 62 guides the roving to the driven draft roller 13 which receives rotation from the driving shaft 20 and, in its turn. transmits rotation to the top roller 26 carried by the bell crank 22. The plate 62 deflects the apron 65 and the roving supported thereon at an angle ss=5-17 from the vertical plane. which makes the roving positively engage the surface of the apron 65 and imparts to it permanent tension in the drafting process.

A no-breakage signal coming from the yarn breakage sensor 7 opens the electrically controlled valve 28, so that compressed-air line is fed via the T-piece 39 to act upon both resilient diaphragms 31 of the respective pneumatic chambers 29 and 30. The diaphragms 31 act through the rods 32, pivoted arms 33 and rods 34 upon the respective bell cranks 21 and 22, in which manner the top rollers 25 and 26 are weighted.

The end coming from the drafting system 3 is twisted (i.e. it attains false twist) in the pneumatic revolving tube 4 mounted for rotation on the plate 42 and having the central bore 52 (Fig. 2) for the passage of the yarn. into which compressed air is fed via the tangential feed passages, supplied from the annular chamber 50 receiving compressed air via the passage 47 from the compressed-air line.

The nozzles 43 and 44 mounted on the plate 42 direct streams of compressed air to blow dust, lint, loose fibres. and so forth off the respective ends of the revolving tube 4. The feeding of compressed air into the revolving tube 4 via the passage 47, and to the nozzles 43 and 44 is effected separately, for the operation of the nozzles not to cause a drop of pressure in the bore 52 of the revolving tube 4, with a corresponding reduction of the torque being developed.

The yarn, somewhat twisted by the action of the air stream, untwists upon leaving the revolving tube 4 (Fig.

1), forming a balloon extending as far as the inclined plate 61 reciprocating jointly with the traverser 9 along the final package 66.

The plate 61 being inclined at an angle from 50 to 700, to the plane in which the yarn is guided to be wound is likewise inclined to the vertical plane. which restrains the untwisting of the yarn and prohibits further propagation of the balloon, thus assisting in close engagement of fibres in the yarn and preventing its "fuzziness".

The yarn guided by the traverser 9 is wound into the yarn package 66 rotated by the friction drive shaft 57.

It can be seen from the above description that with the feed and draft rollers of the drafting system having their own independently actuated and driven top rollers in each yarn path, conditions for better yarn quality, easier operation and maintenance have been created, and influence of the weighting effort of one top roller upon another top roller has been precluded. With one of the bell cranks carrying a top roller also carrying the revolving tube with its blow nozzles and the device for supplying the wetting fluid, the design of the machine has been simplified.

Claims (8)

1. A machine for producing twistless flax fibre yarn, wherein along each yarn path there are successively arranged in the yarn advance direction, from top to bottom: a drafting system including driven feed and draft rollers. top rollers engaging the feed and draft rollers, and bell cranks, one bell crank having an arm carrying the top roller engaging the feed roller and the other bell crank having an arm carrying the top roller engaging the draft roller; a device supplying wetting fluid onto the fibre; a pneumatic revolving tube; a compressed-air line communicating with the pneumatic revolving tube; a yarn breakage sensor; a yarn-winding mechanism with a yarn traverser; and a system for weighting the top rollers of the drafting system, operatively connected with the respective other arms of the bell cranks and of the yarn breakage sensor.

2. A machine as claimed in Claim 1, wherein the system for weighting the top rollers includes an electrically controlled pneumatic valve connected with the yarn breakage sensor. and pneumatic chambers, each having its resilient diaphragm connected via a spring-urged rod and a pivoted arm with the arm of the bell crank, and its internal space under the diaphragm with the compressed air line via supply pipes and the electrically controlled pneumatic valve.

3. A machine as claimed in Claim 1, wherein the bell crank carrying the top roller associated with the draft roller also supports the revolving tube and the device for supplying the wetting fluid. including a tube.

4. A machine as claimed in Claim 1 or 3, comprising blow nozzles at the respective levels of the end surfaces of the revolving tube, communicating with a compressed air line.

5. A machine as claimed in Claim 1, comprising inclined plates adapted to deflect running yarn from a vertical path, arranged, respectively. in front of the draft roller and the yarn-winding mechanism.

6. A machine as claimed in Claim 5, wherein the plate arranged in front of the yarn-winding mechanism is mounted on the yarn traverser and extends at an angle from 500 to 700 to the vertical plane, this plate having projections extending along the direction of the motion of the traverser.

7. A machine as claimed in Claim 5, wherein the inclined plate arranged in front of the draft roller is in the form of a table having its surface extending at an angle from 50 to 170 to the vertical plane. an endless apron running about this surface and the feed roller.

8. A machine for producing twistless flax fibre yarn substantially as hereinbefore described with reference to the accompanying drawings.