Improvement in doubling frames with double-hollow-shaft spindle, with mobile shaft coupling

Abstract: The present invention relates to an improvement in the spindle for double-twist doubling frames in which both of the yarn cheeses (1, 2) are coaxially arranged, over each other, inside the basket of the spindle and each individual cheese is supported by a hollow shaft (15, 18) of its own, with its relevant yarn being reeled off upwards from it and each yarn directly entering the hollow shaft of its own cheese without reaching, while running along its unwinding path, the region which surrounds the other cheese. Said hollow shafts are installed above each other by means of a mobile coupling inside the doubling frame spindle basket. In fact, the hollow shaft (18) by which the (upper) cheese (1) superimposed to the underlying cheese (2) is supported, can be removed from the basket of the spindle and inside said basket said hollow shaft (18) is supported, together with its own cheese, by a support frame (12) which in its turn is removably fastened onto the inner wall of the same basket.

Description: The present invention relates to an improvement in the double-twist spindle for doubling frames in which each yarn cheese is supported on a hollow shaft of its own, with the yarns being reeled off upwards from each cheese, and each yarn reeled off from its cheese directly penetrates its relevant hollow shaft without reaching, while running along its path, the region which surrounds the other cheese. Said hollow shafts are arranged superimposed to each other by means of a mobile coupling inside the spindle basket. The invention can be applied to a double-twist spindle, in order to twist a plurality of yarns together with one another, such as to generate a ply yarn. Said yarns can have any compositions, or structures, and in the instant disclosure and in the appended claims they will be simply referred to as "threads", "yarns" or "ply yarns", with these terms being all used with interchangeable meanings and it is herein understood that these terms include all of the filaments, or filament complexes or fibres, whether of natural origin, or man-made. The term "to twist together" is used herein in the broad sense of combining two or more yarns together with each other; and the broad sense may include the twisting together of a plurality of previously twisted component yarns or threads. The invention is particularly suitable for twisting two yarns together with each other; it can anyway be also suitable for combining three or more yarns; with the limit value of the number of yarns being only determined by practical considerations. It is well-known that in a double-twist spindle the yarns which have to be twisted together with each other, are unwound upwards from at least two yarn cheeses installed over each other on one single hollow, stationary shaft. This unwinding operation, well-known to those skilled in the art, suffers from the drawback that it causes the yarns to interact with each other, with said yarns, before entering the central aperture of the hollow shaft of the spindle, originating loops, rings, helical regions resembling corkscrews, and other shapes of such kinds. It is well-known as well that the yarns unwound on a double-doubling frame, in particular at high speeds, by intersecting each other, are subject to undergo changes in their tension, which sometimes may reach excessive values, In the case of a plurality of yarns -- whether spun from staple fibres or from synthetic filaments --such excessively high tension values are undesirable, in that the yarns undergo stresses and severe friction contacts due to their intersecting during their continuous unwinding from the feed cheeses. As a consequence, they will be excessively stretched, damaged or, in the extreme case, they will be broken. The breakage of the yarn causes the production process to be discontinued and therefore reduces the economic outcome and the productivity of this kind of facilities. The double-twist spindles having this structure known from the prior art show the further drawback that the yarn is caused to run into contact with, and to creep along, the external peripheral surface of the mutually superimposed feed cheeses, which may cause the same yarn to be damaged by abrasion, with its mechanical strength being decreased. Therefore, the risk exists that the mutual intersecting of the yarns and the above mentioned creeping along the external peripheral surfaces of the same cheeses may cause dust and air-borne fibrils to be formed, which, after a certain time period, are twisted together with the yarn and can hence cause twist faults. On the other hand, owing to said effect of said yarns repeatedly intersecting and getting in each other's way, and due to the effect of the frequent creeping contacts along the portions of the external surfaces of the mutually superimposed feed cheeses, a larger energy consumption per each spindle occurs, and therefore an increase in the cost of the produced ply yarn is experienced. Many attempts were done in the past, in order to secure that the yarns do not interfere, getting in each other's way during their orbital unwinding rotation before penetrating the upper open end of the hollow shaft of the spindle. Typical examples of said attempted solutions proposed in the art are the reeling-off arms positioned in the upper region, or in the middle, or in the lower region, of the mutually superimposed cheeses in course of unwinding. Said reeling-off arms are dragged by the yarn to rotate around the hollow shaft of the spindle, in that they are centered on it and are used since long as auxiliary means for the unwinding of the yarns which have to be twisted. DE-B-1 159 826 patent is one from the numerous examples of application of a plurality of reeling-off arms. Unfortunately, these latter are not capable of securing a contant tension of the yarns in course of unwinding and therefore to not exclude that loops, rings, and helical portions -- which become apparent in the ply yarn, as those skilled in the arm are well aware of --may be formed. Furethermore, said reeling-off arms render enormously more complex the construction and the use of the twisting spindle. Therefore, the use of such reeling-off arms does not represent a satisfactory solution in the production of ply yarns on double-twist spindles. Furthermore, other applications have been provided, as disclosed in CH-A-398 392 and US 3,648,449 patents. CH-A-398 392 provides two cheeses coaxially arranged over each other, with the yarn from the upper cheese being unwound downwards and the yarn from the lower cheese being unwound upwards. Such a specific technical solution suffers from a considerable drawback as regards the reeling off of the yarn from the upper cheese. In fact, this yarn, by running downwards, is subject to simultaneously unwinding in a plurality of turns which, by collapsing by gravity, cause the same yarn to loosen, thus causing changes to occur in the tension of both yarns which have to be twisted with each other, causing conditions of uneven twisting. This effect is undesired in that it wastes the appearance of the end ply yarn and additionally causes a decrease in the tensile stress thereof, owing to the fact that the individual yarns are loaded with an uneven pulling load. The technical solution of said patent is furthermore difficult to be applied in the use of cone-frustum-shaped cheeses, above all if said cheeses have high conicalness values and high winding strokes, as those skilled in the art are well aware of. US-A-3 648 449 patent, and precisely in its graphic representation as shown in Figure 1B attached to it, provides two coaxially arranged cheeses, positioned over each other, with the yarn from the lower cheese being unwound upwards following a strongly bent path; the yarn is therefore highly tensioned. The two yarns run along completely separated paths, but are sent to the inlet aperture of the central hollow shaft with strongly different tension values owing to the different and complex running path the yarn unwound from the lower cheese runs along. Also in said technical solution, frequent actions of uneven twisting are experienced, with the outer appearance of the end ply yarn being damaged. When the processed yarns are very thin and the unwinding thereof takes place at a very high speed, disturbances caused by the breakage of the yarn from the bottom cheese can occur. Furthermore, said technical solution is generally not easy to be constructed and applied, and moreover its use is rather difficult. In other terms, its construction is more expensive and its use is more complex than of the technical solution proposed by the instant finding. DE-A-1 905 049 discloses a double-twist spindle according to the preamble of claim 1 whereby the upper cheese may not be satisfactory centered. The purpose of the present invention as disclosed in the claims is of getting rid of the above cited drawbacks by providing a spindle for double-twist doubling frames for producing ply yarns, which shows the following advantages: it makes it possible yarns to be twisted on the double-twist spindle, which come from cone-frustum-shaped cheeses with any values of conicalness and with considerable axial outline dimensions, i.e., with any values of yarn winding stroke; with the possible limitations only depending on the dimensional capability of the doubling frame to house the cheeses; it enables the yarns to never interfere with each other while they are getting reeled off from the two mutually superimposed cheeses; it makes it possible a perfectly symmetrical unwiding of the two feed cheeses to be achieved, with the tensions of the yarns unwound from said cheeses being consequently uniform. In fact, said yarns run along a reeling-off path which is identical for each of them, with the yarn running paths being simultaneously separated from each other; it makes it possible the formation of loops, rings, and helical portions to be eliminated, with any breakages of the yarns which are being unwound in order to produce the ply yarn being simultaneously eliminated; it enables any rotary elements, such as reeling-off arms, or any stationary spacer elements with either fixed or variable geometry, such as guide plates or guide disks for the unwound yarns, to be eliminated. The purpose of the invention is obtained by providing a double-twist spindle comprising the features of claims 1. A further advantage of the spindle for double-twist doubling frames according to the present invention is that it is capable of twisting yarns of any structures, including cotton and yarns suffering from low-speed reeling off problems, in that the yarns fed in order to produce the end ply yarn do not intersect each other and, as a consequence, do not undergo any wearing, nor do they undergo any tension changes while they are being unwound. The latter advantage makes it possible a ply yarn to be obtained, whose quality is higher and with lower operating costs. Incidentally, the best quality springs from the absence of wear due to the creeping of the individual yarns on each other, from the perfectly identical tensions shown by said yarns, and from air-borne dusts and fibrils being not generated, in that the yarns run along different -- and simultaneously of identical shape -- paths during the whole unwinding step. For practical use, a substantial advantage is that the spindle for double-twist doubling frames makes it possible the feed cheeses to be rapidly charged to the container basket, and also makes it possible their support tubes to be rapidly removed when the unwinding is complete, i.e., the replacement of the cheeses has to be quick, and easy to be performed. This feature is achieved, e.g., due to the fact that the hollow shaft on which the cheese which is superimposed to the underlying cheese is installed, is supported in its turn by an element resting and centered on elements fastened to the inner surface of the cheese-bearing basket. Therefore, in order to charge and discharge the cheeses used to feed the spindle according to the present invention, no complex operations are required from the user, nor does he have to use any auxiliary tools. These and still further advantages are all achieved by the present improvement in the doubling frames equipped with double-yarn twisting spindles in order to produce ply yarns, in which the two cheeses are coaxially arranged over each other inside the basket of the same twisting spindle and whereby each undividual yarn feed cheese is supported on a hollow shaft of its own, with the yarn being reeled off from all of said cheeses upwards, or anyway in the same direction of reeling off of the yarns of the other cheeses, and each yarn directly enters the hollow shaft of its own cheese without reaching, during its running, the region which surrounds the other cheese, and without the aid of any reeling-off arms or elements. According to a form of practical embodiment, the hollow shaft on which the cheese which is superimposed to the underlying cheese is supported, can be slid out from the basket, and inside said basket is supported, together with its own cheese, by a support resting on elements fastened onto the inner wall of the same basket inside which the cheeses which are being reeled off are contained. The present invention is explained in greater detail in the following by referring to the example of practical embodiment thereof which is shown in the drawing of the hereto attached single drawing table. Further peculiar features and characteristics thereof will be explained in the following, it being anyway understood in this regard that the invention can be practiced according to many different forms of practical embodiment. In the drawing, the figure schematically shows, in axonometric pespective, a partial axial sectional view of the spindle for double-twist doubling frames, according to the present invention, in a form of practical embodiment of two mutually superimposed, cone-frustum-shaped cheeses which feed the yarns needed in order to form the end ply yarn. In said figure, also the path is shown of the yarns which are reeled off, each yarn from its own cheese, and enter their respective hollow shaft. For the sake of clearness of the whole view, the parts which are not necessary in order to understand the invention are not shown in the figure, in that they are already known from the prior art and do not concern the operation of the present invention. In the hereto attached drawing table, we have that: 1 and 2 are the two cone-frustum-shaped cheeses which will feed the yarns in order to originate the ply yarn obtained from the spindle 25 by means of its double-twisting action. Said mutually superimposed cone-frustum-shaped cheeses 1 and 2 are arranged with their taper being directed upwards, i.e., their shortest diameter is at the top and their orientation is the same; 18 is the upper -- substantially stationary -- hollow shaft of the spindle 25. Said hollow shaft 18 is provided with a circumferential element 19 in a middle region thereof, and with a bottom hub 11 made integral with radial support elements 12. These latter preferably consist of three radial beams arranged at an angle of substantially 120° to each other. The element 19 and the support hub 10 cause the cheese 1 to be centered around the hollow shaft 18, by getting coupled with the inner surface of the conical tube 6 of the cheese 1. As a consequence, the axis of said hollow shaft 18 and the axis of the cone-frustum-shaped cheese 1 are caused to coincide; 25 is the spindle according to the present invention, whose axis can be vertical, horizontal, or inclined. Incidentally, said spindle 25 will be described herein in its essential parts only; it is disclosed in greater detail only in the parts concerned by the instant invention. The reference numeral 35 indicates the pulley which causes the rotary portion, per se known, of the spindle 25, to revolve. Said pulley 35 is normally caused to revolve by a belt, or by means of other drive means, all of which are known from the prior art, and are meaningless for the purposes of the present invention. The reference numeral 20 indicates the upper end -- also denominated "upper reeling-off head -- of the hollow shaft 18, and the yarn 21, unwound from the cheese 1 superimposed to the bottom cheese 2, enters the central aperture thereof and runs downwards; 16 is the upper end -- also denominated "lower reeling-off head -- of the hollow shaft 15, and the yarn unwound from the cheese 2 enters the central aperture thereof together with the yarn 21 leaving the hollow shaft 18, and both of said yarns run downwards; 9 is the container basket which houses the mutually superimposed, yarn-feed cheeses. Said basket is prevented from rotating by stop magnets (not shown in the figure). The reference numeral 12 indicates the support structure constituted by three or more radial elements, rigidly connected with the support hub 10 in the central region and resting at their peripheral portion onto the circumferential, shoulder-like, protruding element 3. Said protruding element, also said "circumferential insert" is a rigid element and therefore constitutes an enbloc body with the inner surface 14 of the cheese-containing basket 9; 4 is the tube of the cone-frustum-shaped cheese 2. The inner surface of said tube, by getting coupled with the circumferential protrusions 8 and 5, causes the cheese 2 to be centered around the hollow shaft 15; 33 is the ply yarn which radially leaves the yarn accumulator disk 30 through the duct 29 provided in said yarn accumulator disk for the same ply yarn; 24 is the expansion device provided in order to control the tension of the yarn inside the spindle. In the herein depicted form of practical embodiment, said device is the "expansion plug" already known in the art, constituted by two cylindrical elements axially arranged and kept in their position by at least one elastic force, the value of which can be adjusted, with the tension given to the passing yarn being consequently adjusted; 34 is the cup, or rotary plate, whose external edge guides the ply yarn after its leaving the duct 29; 32 is the circular shell acting as the container for the balloon of ply yarn 33. In the art, said shell is given the name of "balloon-breaker container"; 27 is a yarn-guide ring which determines the top of the balloon of the end ply yarn 33 which ply yarn, by running upwards, feeds the winding unit (not shown in the figure). The operating way of the spindle for doubling frames according to the present invention is disclosed now by referring to the single hereto attached figure, which illustrates an easily understood constructional configuration. Let's suppose that the spindle according to the present invention is fed with feed cheeses, in order to enable said spindle to produce the ply yarn. The yarn-guide ring 27 is lifted, the hollow shaft 18 -- and consequently the support hub 10 and the support frame 12 which constitute an enbloc body with said hollow shaft 18, are removed from the basket 9. A yarn feed cheese 2 is charged to the basket 9 and is installed on the hollow shaft 15, whose axis is the centering axis for said cheese 2,thanks to its circumferential protrusions 8 and 5 integral, as one single body, with said hollow shaft 15. The leading end of the yarn is fastened onto a nylon needle by being wound around it. Said nylon needle is then slid through the central (inlet) aperture 16 of the hollow shaft 15. Said needle, together with the leading end of the yarn 7 fastened to it, shall be caused to exit the duct 29 of the accumulator disk 30 and then move upwards along the annular air space bounded by the basket 9 and the container 32. In that way, the leading end of the yarn of the cheese 2 is lifted up to the outlet defined by the top edge of the container 32. The hollow shaft 18, around which the feed cheese 1 is housed, is then inserted inside the basket (the axis of said cheese 1 coincides with the axis of the hollow shaft 18 thanks to the inner surface of its inner tube 6 getting coupled with the circumferential element 19 and the support hub 10 provided on said hollow shaft 18). The support frame 12 is laid on the circumferential shoulder 3. The leading end of the yarn 21 of the cheese 1 is fastened onto a nylon needle. Then, by said latter nylon needle being slid through the central (inlet) aperture 20 of the hollow shaft 18, said leading end of yarn 21 is caused to leave the container 32 at the outlet defined by the top edge of said container 32 (all the above is done in the same way as of the operation disclosed for the leading end of the yarn 7 of the underlying cheese 2.) In that way, both individual yarns 7 and 21 come to stand side-by-side of each other at the outlet defined by the top edge of the container 32. Said individual yarns 7 and 21 will be passed together with each other through the yarn-guide ring 2 and, while being so retained, will be sent to the winding unit (not shown in the figure). Incidentally, all of the above operations are carried out with the spindle 25 being kept stationary, i.e., the yarn accumulator disk 30, the rotary plate 34 and the pulley 35 are stationary. When the rotation of said elements is enabled, and the brake -- the brake is not shown in the figure, in that it is already per se known from the prior art -- is released, the operation of twisting in order to produce the twisted yarn 33 is started. Modifications of applicative nature may be provided, and therefore the elements disclosed and illustrated herein can all be replaced by other equivalent elements, without thereby departing from the purview of the inventive idea, as said purview is claimed in the hereto appended claims. The terminology relevant to "up" and "down", "top" and "bottom", and so forth, is used in the instant disclosure and/or in the appended claims, for the only purpose of describing the relation of certain elements relatively to other elements when the spindle is standing in its normal vertical position, and should not be construed as being limitative to this precise position.

Claims: A double-twist spindle (25) for doubling frames for producing ply yarns (33), comprising a basket (9) for receiving two cheeses (1,2) coaxially over each other, each of the cheeses (1,2) being arrangeable about an own hollow shaft (18,15) for being supported therefrom whereby the yarns (6,7) of the cheeses (1,2) are reeled off from the respective cheeses (1,2) substantially in the same direction for directly entering the respective hollow shafts (18,15) from above without reaching, during their running the region which surrounds the other cheese, and without the aid of any reeling-off arms or elements, the lower hollow shaft (15) being rigid with the basket (9) and the upper hollow shaft (18) being rigid with a support removable from the inside of the basket (9), and the hollow shafts (18,15) each having an upper reeling-off hollow head (20,16), characterised in that said hollow shafts (18,15) each have two axially spaced apart centering elements (10,19; 5,8) for the tubes (6,4) of the cheeses (1,2). A double-twist spindle according to claim 1, characterised in that said support comprises arms (12) extending radially from the bottom centering element (10) of the upper hollow shaft (18), and in that said basket (9) has a circumferential inner protrusion (3) for sustaining said arms (12).

Inventors: COLLI LUIGI, COLUSSI VITTORIO, COLLI, LUIGI, COLUSSI, VITTORIO
Applicants: SAVIO MACCHINE TESSILI SRL, SAVIO MACCHINE TESSILI S.R.L.
Application year: 1990
Main classification: D01H1
IPC codes: D01H1