IMPROVEMENTS TO A SPINNING SYSTEM HAVING A ROTARY BALLOON CHECKING DEVICE

Abstract: Improvements to a spinning system (10) having a rotary balloon checking device (16), the checking device (16) consisting of an upper cylindrical portion (27) and lower frustum-shaped portion (28) which surround a yarn package (14) being formed, the upper portion (27) being upheld by a support (17) with bearings which is solidly fixed to a rail (19) of a spinning machine, the yarn (22) on arrival from a drafting unit (20) of the spinning machine forming a balloon between a thread eye (21) and the top of the checking device (16) and thereafter constituting an inner controlled segment (125) and an outer segment (225) able to slide on the checking device (16) during its descent to be wound on the yarn package (14), the yarn (22) being guided (29) at the lower edge of the frustum-shaped portion (28), the improvements comprising: - the outer slidable segment (225) of yarn positioned in correspondence with the upper part of the upper cylindrical portion (27) of the checking device (16), and - an element (31) to the guide the yarn (22) towards the yarn package (14) in correspondence with the lower end part of the frustum-shaped portion (28) of the checking device (16), such guide element (31) being located on the inner surface of the lower end part of the frustum-shaped portion (28).

Description: This invention concerns a spinning system having a rotary balloon checking device. To be more exact, the invention concerns a segment of yarn able to slide on the rotary balloon checking device and also the type of attachment for the yarn on the checking device so as to guide the yarn in being wound onto the yarn package. Spinning system according to the invention is suitable to ensure better performance of spinning and twisting machines employing a rotary balloon checking device and better operating conditions for the operatives in charge of such spinning and twisting machines. Spinning systems with a rotary balloon checking device are known in the art. The system employed in the embodiment disclosed in patent application IT 83441 A/85 in the name of the present applicant provides a rotary balloon checking device which makes possible, starting with the winding tension, the predetermination of the reduction of that tension to the required value on the basis of the balloon. Such reduced tension, which coincides with the spinning tension, is normally obtained by choosing a suitable extent of surface for the sliding of the yarn on the outside of the lower frustum-shaped portion of the rotary checking device. The yarn, which in this case is in the upper cylindrical portion of the checking device, is merely guided by the inner surface of the upper portion or is guided by means of a tube or conduit. At a given point the yarn comes out from the upper cylindrical portion onto the outer surface of the device and as we said, is made to slide along a given extent of surface on the frustum-shaped portion of the checking device. The yarn leaves the lower edge of the checking device and is wound onto the yarn package by passing through a hole or appropriate lead-in in the checking device. In any event the yarn is guided in the last controlling part of the checking device before leaving the device and being wound onto the yarn package. Some shortcomings are entailed in the configuration described in IT 83441 A/85. First of all, the re-ascent of the twist from the point or zone in which it is imparted to the yarn, up to the drafting unit encounters some hindrances. As the twist is imparted in the sliding stretch on the outer surface of the checking device and as the yarn is thrust against that surface, the twist in its re-ascent towards the drafting unit is hindered in the upper cylindrical portion of the device, against the inner surface of which the yarn is thrust by the forces in question. Moreover, such hindrance is of a variable value since the contact between the yarn and the controlling surface may vary from moment to moment owing to the unavoidable geometric variations in the balloon due to the pulsations of the tension. It is known that in spinning or twisting operations the fact that the twist can re-ascend in a continuous, uniform manner is of great technological importance. A further drawback consists of the fact that the rotation of the checking device by the spindle takes place by means of a very short length of yarn which is free in the air, particularly at the moment when it is wound on the outer diameter of the yarn package. Another shortcoming is the fact that the yarn is rigidly engaged at the edge of the checking device by a hole or notch through which it passes. This does not allow the yarn to react resiliently, except to a very limited extent, to any irregularity in the spinning conditions, such as any irregularity in the motion of the spindle or any geometric irregularity in the yarn package or any of the many other possible irregularities. The outcome may be an increase in the number of breakages of the yarn or a deterioration of the quality of the yarn. Document FR 967.411 deals with a shell or sheath like a bell, which comprises on the lower end portion of its inner surface a thread guide conformed structurally so as to enable the yarn to pass from above downwards along the inner wall of the shell towards the thread guide device. This definition has been inferred from Fig. 1 and from the abstract included in the document since in that document there are no other points where there is a specific mention of the functional characteristics of the thread guide. The thread guide performs the tasks of diverting the yarn with one single position of location of the yarn at work and therefore tends to solve different problems from those with which our present invention is concerned. Document CH 631.753 deals with a roving-clamping device which can be actuated, when the yarn breaks, crosswise to the direction of feed of the roving in the area of entry into the feed rollers of the drafting unit, as set forth in the main claim. This device obtains a lateral diversion of the roving with a gripping of the same when the roving breaks, that is to say, the device takes action when the roving breaks, and this is in conditions different from our invention. The present applicant has studied, tested and obtained improvements to a spinning system having a rotary balloon checking device which are able to overcome all the shortcomings of the known art. According to the invention the extent of surface on which the yarn slides on the checking device, such extent being suitable to pre-determine the required spinning tension, is located in correspondence with the upper part of the cylindrical portion of the checking device above the support which upholds the device itself. The length of the extent of surface on which the yarn slides can be varied and pre-set. According to the invention the yarn descends within the device from the cylindrical portion until it reaches an element which guides it towards the yarn package. In the end part of its descent at the lowest zone of the frustum-shaped portion of the device the yarn descends separated from the inner surface of that zone. This is obtained by the inclusion of the guide element, of which the conformation and arrangement on the device are also such as to enable the guiding point to be displaced during the spinning so as to take account of the unavoidable disturbances which take place during the spinning cycle. In other words the point at which the yarn is guided towards the yarn package is not a stationary point but can be varied suitably within a given field which depends on the geometric conformation of the guide element. The yarn becomes involved in a situation of unstable equilibrium and can react readily to any variation, even if momentary, in the spinning conditions. The guide element is suitably conformed for swift insertion of the yarn during the operations of the spinning cycle. The improvements according to the invention entail a plurality of advantages as follows: the twist is imparted to the yarn at a position very near the drafting unit, and therefore the length of the re-ascent of the twist is very short, in practice the twist re-ascends along an extent of yarn free in the air without hindrances or points of resistance, this extent corresponding substantially with the distance between the drafting unit and the upper terminal edge of the rotary checking device, the re-ascent of the twist takes place in a segment of yarn subject to a tension less than the value of the winding tension, the descending segment of yarn within the checking device towards the guide element is already fully twisted and is therefore less liable to damage by sliding on the inner surface of the wall of the checking device, the descending segment of the yarn comprises a high tension substantially equal to the winding tension, and therefore the yarn is not thrust powerfully against the first descent portion of the inner surface of the checking device and remains separated from the wall of the device in the final descent portion, the inclusion of the guide element makes it possible to have a segment of yarn free in the air upstream of the guide element, this free segment sharing with the final winding segment in ensuring a given adaptability in the spinning system, the yarn can move on the guide element and can thus react to variations, even if momentary, in the tension due to functioning irregularities, the wear on the guide element is considerably reduced by continuous variations in the point of its contact. with the yarn, and the improvements adopted obtain a conformation of the system which enables the yarn to be readily inserted since the yarn can be passed freely through the whole checking device upwards from below, for instance by pneumatic propulsion of the end of the yarn. The invention is therefore obtained with the contents of Claim 1 and the dependent claims. The attached figures, which are given as a non-restrictive example, show the following: Fig.1 shows an embodiment of the prior art; Fig.2 shows an embodiment according to the invention; Fig.3 shows diagrammatically a front vertical section of the lower part of the checking device together with a guide element according to the invention; Fig.4 gives a side view of Fig.3; Fig.5 shows a diagram of the checking device of the invention from below; Fig.6 gives a diagram of a guide element and guiding conditions according to the invention. Fig.1 shows an embodiment of the prior art; a spinning system 10 is applied to a spindle 11 which in this example is driven by an independent motor 12 fitted to a rail 13 energized by vertical reciprocating motion, indicated by the arrow, so as to form a yarn package 14 on a tube 15. A balloon checking device 16 consists of an upper cylindrical portion 27 and a lower frustum-shaped portion or distributor portion 28. The checking device 16 surrounds the yarn package 14 being formed and lets the top of the tube 15 protrude upwards. The cylindrical portion 27 is upheld by a support 17 with bearings solidly fixed to a rail 19 of the spinning machine, the rail being stationary in this example. A brake 18, of a magnetic type for instance, serves to graduate the winding tension in a known manner. Yarn 22 arriving from a drafting unit 20 constitutes a first segment 23 which reaches a thread eye 21. A second segment 24 of yarn between the thread eye 21 and the upper end of the checking device 16 forms a balloon. After entering the device 16, the yarn constitutes a controlled extent 25, of which a first segment 125 is within the device 16 while a second segment 225 is outside the device and is substantially on the frustum-shaped portion 28. The yarn 22 emerges from the cylindrical portion 27 through a hole 26. The yarn 22 is guided in a lead-in 29 comprised in the lower edge of the frustum-shaped portion 28 and is then wound onto the yarn package 14. Fig.2 shows an embodiment according to the invention in which the same parts or parts having the same functions bear the same reference numbers as in Fig.1. The yarn 22 arrives at the top of the checking device 16 from the drafting unit 20 as in the prior art. It enters into the inside of the cylindrical portion 27 at the top of the device and runs therein for a short distance; it emerges through the hole 26 and, after forming a sliding segment 225 on the outer surface of the cylindrical portion 27, re-enters that portion 27 through a second hole 126. Notches 30 and 130 are comprised in the cylindrical portion 27 for the introduction of the yarn 22 into the holes 26 and 126 respectively. A third hole 226 is also comprised in the same zone so as to pre-determine a different length of the sliding segment 225. A plurality of holes 26-126-226 can be included to obtain different combinations of sliding segments 225 as required. The yarn 22 proceeds inside the cylindrical portion 27 along a controlled segment 125 in which it is in contact with the inner surface of that portion 27. It then proceeds within the frustum-shaped portion 28 of the device 16 along a segment 325 substantially separated from the inner surface of the frustum-shaped portion 28. The separated segment 325 of yarn cooperates at its lower end with a guide element 31, which may be a hook or the like for instance, so as to form a free segment 425 of yarn for winding on the yarn package 14. The guide element 31, which is fixed suitably to the inner, lower end part (see Figs. 3, 4, 5 and 6) of the frustum-shaped portion 28, comprises a substantially straight part 32 or a part having a very slight curvature. This part 32 enables the segments 325 and 425 of the yarn to move freely, as shown with dashes in Fig.3. Such straight part 32 of the guide element may have a length "L" advantageously, but not only, within a range between 3 and 15 mm. This straight part 32 is inclined at an angle "gamma", which is advantageously about 45°, to the plane of the lower edge of the frustum-shaped portion 28, such angle being suitable to enable the yarn segments 325 and 425 to react at once and therefore to be displaced in relation to the spinning irregularities. The substantially straight part 32 lies on a plane "pi" identified by the direction of arrival (arrow 33) of the separated segment 325 on the straight part 32 and by the direction of departure (arrow 34) of the free segment 425 of the yarn 22 from the straight part 32. The straight part 32 will advantageously be at about a right angle (angle "beta" of about 90° in Fig.6) to the bisector 35 of the angle formed by the direction of arrival 33 and of departure 34 of the yarn 22 on the straight part 32, in correspondence with a mean diameter "Dm" of the yarn package 14.

Claims: A spinning system (10) having a rotary balloon checking device (16), the checking device (16) consisting of an upper cylindrical portion (27) and lower frustum-shaped portion (28) which surround a yarn package (14) being formed, the upper portion (27) being upheld by a support (17) with bearings which is solidly fixed to a rail (19) of a spinning machine, the yarn (22) on arrival from a drafting unit (20) of the spinning machine forming a balloon between a thread eye (21) and the top of the checking device (16) and thereafter constituting an inner controlled segment (125) and an outer segment (225) able to slide on the checking device (16) during its descent to be wound on the yarn package (14), the yarn (22) being guided (29) at the lower edge of the frustum-shaped portion (28), being characterized in comprising: the outer slidable segment (225) of yarn positioned in correspondence with the upper part of the upper cylindrical portion (27) of the checking device (16), and an element (31) to guide the yarn (22) towards the yarn package (14) in correspondence with the lower end part of the frustum-shaped portion (28) of the checking device (16), such guide element (31) being located on the inner surface of the lower end part of the frustum-shaped portion (28). A spinning system as claimed in Claim 1, in which the outer sliding segment (225) comprises at least one passage (26-226) for the exit of the yarn (22) from the inside to the outside of the cylindrical portion (27). A spinning system as claimed in Claim 1 or 2, in which the outer sliding segment (225) comprises at least one passage (126) from the outside to the inside of the cylindrical portion (27). A spinning system as claimed in any claim hereinbefore, in which the passages (26-126-226) cooperate with notches (30-130) in the swift insertion of the yarn (22) in the passages (26-126-226). A spinning system as claimed in any claim hereinbefore, in which the guide element (31) is conformed substantially as a hook and comprises a straight or almost straight part (32) on which the terminal separated segment (325) of the controlled segment (125) and the segment (425) free for winding on the yarn package (14) can run freely. A spinning system as claimed in any claim hereinbefore, in which the guide element (31) keeps the free end segment (325) substantially separated from the inner surface of the frustum-shaped portion (28). A spinning system as claimed in any claim hereinbefore, in which the substantially straight part (32) of the guide element (31) has a length (L) advantageously between 3 and 15 mm. A spinning system as claimed in any claim hereinbefore, in which the substantially straight part (32) is inclined at an angle "gamma", which is advantageously about 45°, to the plane of the lower edge of the frustum-shaped portion (28). A spinning system as claimed in any claim hereinbefore, in which the substantially straight part (32) lies on a plane "pi" indentified by the direction of arrival (33) of the terminal segment (325) on the straight part (32) and by the direction of departure (34) of the free segment (425) from the straight part (32). A spinning system as claimed in any claim hereinbefore, in which the straight part (32) lies substantially at a right angle to the bisector (35) of the angle formed by the directions of arrival (33) and departure (34) of the yarn (22) on the straight part (32), in correspondence with a mean diameter (Dm) of the yarn package (14). A spinning system as claimed in any claim hereinbefore, in which the guide element (31) is interrupted at one side for introduction of the yarn (22).

Inventors: GERIN, UMBERTO, LANCEROTTO, FABIO, MARCHIORI, MIRKO
Applicants: MASCHINENFABRIK RIETER AG
Application year: 1988
Main classification: D01H1
IPC codes: D01H1, D01H7