Weft thread lubrication for textile machines, particularly weaving looms and the like

Abstract: A weft thread lubrication device for textile machines, particularly weaving looms and the like, comprising: an oil supply reservoir (13-130) which, by means of respective delivery ducts (17-141-142), distributes the oil to a plurality of individual lubricators (14-114) arranged in front of respective spools (11-110) of weft thread (FT) supported by a creel structure (10-100), each lubricator having an annular felt (22-226) that is impregnated by the oil and is crossed by the weft thread which, by means of the unwinding balloon (B) adheres to the inner surface of the axial hole of the felt, absorbing the oil; and recovery means (24-25-151) that receive the excess oil from the lubricators (14-114) to recycle it into the oil supply reservoir (13-130).

Description: The present invention relates to a device for lubricating the weft thread that is fed to textile machines and particularly to weaving looms, knitting machines, and the like. In conventional weaving processes performed with modern high-speed shuttle-less looms, such as air jet looms, projectile looms, and the like, the weft thread is unwound, from respective spools supported by a creel, by pre-feeders interposed between each spool and the loom and accumulate a reserve of weft in the form of turns of thread that subsequently unwind from the feeder when requested by said loom. In order to facilitate weaving, and particularly the correct insertion of the weft between the warp threads, it is advantageous, due to the high beat rate of said looms, to lubricate the weft thread beforehand, in order to eliminate or at least minimize the sliding friction of said weft against the warp threads. Pre-lubrication of the weft thread also allows to obtain a more uniform thread that can accordingly be processed better and is not subject to jamming and therefore to breakages. Usually, the weft thread is lubricated with low-viscosity vegetable-based oils or mixtures of oils when it is taken from the spool to be woven immediately, and the treatment must be performed in such a manner as to ensure uniform lubrication despite the unwinding speed of the thread, avoiding both excessive and insufficient impregnation. The thread is currently lubricated by individual lubricating devices, which are interposed between each spool and the respective weft pre-feeder; said devices comprise an oil reservoir, in which a strip of felt or the like dips and becomes impregnated with said oil by capillary action. The thread is made to slide in contact with said felt strip, from which it receives the lubricating oil. More particularly, in some conventional devices the felt strip is provided with a hole through which the weft thread passes. Said weft thread, by arriving directly from the spool, is subjected, in the space lying in front of said hole, to an unwinding rotation that makes said thread trace a solid of revolution known as a "balloon" and thus termed hereinafter; by virtue of this balloon, the thread repeatedly touches the internal surface of the hole, absorbing oil from the felt. These conventional devices have numerous severe drawbacks and therefore do not fully meet the expected requirements. In particular, said conventional lubrication systems allow no control over the amount of oil absorbed by the thread, since said absorption depends exclusively on the impregnating capacity of the felt, which in turn depends, in a fully unpredictable way, on various factors and in any case degrades quickly over time. Furthermore, in view of the large number of installed devices (a pool of 100 looms requires the installation of approximately 800 devices), due to obvious reasons of bulk the oil reservoir of each one of said devices must have a limited capacity, typically between 0.14 and 0.25 liters, and this requires frequent replenishments of the level of the oil and accordingly requires constant monitoring of the equipment, with obvious economical drawbacks and limited assurance of correct and constant lubrication. FR-785 988 A discloses a weft thread lubrication device as defined in the preamble of claim 1. A principal aim of the present invention is to eliminate these and other drawbacks of conventional lubrication devices, and said invention achieves this aim with a device having the specific characteristics described in the appended claims. Substantially, the invention is based on the inventive concept of adopting a single oil supply reservoir having a high capacity, typically between 10 and 100 liters, and of distributing the oil by means of respective delivery ducts to a plurality of individual lubricators arranged in front of corresponding spools, each lubricator being provided with a felt that is impregnated by the stream of oil that affects it; the felt of each lubricator being provided with a respective central hole, through which the weft thread passes, said thread rotating inside said hole as a consequence of the balloon formed by its unwinding from the corresponding spool. According to an embodiment of the invention, each lubricator is fed by gravity and is provided with a dosage device that allows to make the desired amount of oil reach the felt. The excess oil that is not absorbed by the weft thread is collected by gravity in a discharge duct that ends in a corresponding collecting reservoir, from which it is periodically recycled into the supply reservoir by a pumping means. Level sensing means are provided both on the supply reservoir and on the collecting reservoir; the first means are provided to offer at least a refill signal and the second means are provided to start or stop the recycling pumping means when the oil in the collecting reservoir reaches a preset maximum or, respectively, minimum level. According to a different embodiment of the invention, instead of the reservoir that feeds the oil by gravity to the individual lubricators, a pressurized supply circuit is used, which includes at least one electric pump capable of feeding pressurized oil to a delivery duct from which branches for feeding the oil to corresponding lubricators extend, and a recovery circuit provided with a corresponding unpressurized recovery duct, in which branches connected to said lubricators merge, said branches collecting the excess oil discharged by said lubricators and conveying it to a centralized collecting reservoir, from which the suction duct of said electric pump draws. An automatic dosage device is installed at the inlet of each lubricator and includes a stem-like shutter contrasted by a spring the rigidity whereof is calculated as a function of the operating pressure of the pressurized supply circuit. According to this embodiment, it is possible to provide a centralized lubrication system that is capable of supplying, with a constant and controlled flow-rate, any number of lubricators, regardless of their mutual arrangement, particularly even if they are arranged in parallel-fed groups. Further characteristics and advantages of the device according to the present invention will become apparent from the following detailed description thereof, given with reference to the accompanying drawings, which are provided by way of non-limitative example and wherein: figure 1 is a schematic elevation view of the device according to an embodiment of the present invention, showing said device associated with a creel for supporting a plurality of spools of thread; figure 2 is an enlarged-scale axial sectional view of a lubricator of the device of figure 1; figure 3 is a front elevation view of the structure of a creel for supporting spools of thread, with the device according to a different embodiment of the invention associated therewith; figure 4 is a sectional view, taken along the plane IV-IV of figure 3; figure 5 is an enlarged-scale view of a detail of figure 3; figure 6 is an enlarged-scale axial sectional view of a lubricator; figure 7 is the block diagram of a system composed of a plurality of creel structures according to figure 3. With reference to figures 1 and 2, the reference numeral 10 generally designates the structure of a creel that supports a plurality of spools 11a-11b...11n of weft thread FT that is unwound from the corresponding spool by means of a respective weft feeder, not shown, that feeds the loom or other textile machine. The thread lubrication device, generally designated by the reference numeral 12, is associated with the creel 10. The device 12 comprises, substantially and in combination, an oil supply reservoir 13 arranged at the upper part of the structure of the creel 10, at a level that is in any case higher than the level of the uppermost horizontal row of spools 11b, and a plurality of lubricators 14a-14b...14n, each arranged adjacent to a corresponding spool 11a-11b...11n and in front of it (relative to the unwinding direction of the thread FT, indicated by the arrows in the figure). In figure 1 only two lubricators and corresponding spools (14a, 11a; 14b, 11b) are shown. The reservoir 13 has a substantial capacity, at least between 10 and 25 liters, and a distributor 15 is associated therewith and receives the oil from said reservoir by gravity, with the interposition of an electric valve 16 that is optionally adapted to interrupt its gravity flow. A plurality of delivery ducts 17a-17b...17n (only two of which, 17a, 17b, are shown) branches out from the distributor 15, and each duct feeds .oil, by gravity, to a corresponding lubricator 14a-14b...14n. The ducts 17 are preferably connected to the distributor 15 by virtue of the interposition of respective manually-adjusted dosage devices 18a-18b...18n (only two of which, 18a, 18b, are shown) that will be described hereinafter. Each lubricator 14 is configured as shown in the detail view of figure 2 and comprises a body 19 made of rigid material, preferably metal or metal alloy, that is provided with a front funnel-shaped hole 20 in which the thread FT also passes. The largest cross-section of the hole 20 is directed towards the spool 11 of thread, which is arranged to the rear, and the smallest cross-section is arranged adjacent to an annular seat 21 that contains a corresponding annular felt 22 provided with a central hole 23 in which the thread FT also passes. The oil supply duct 17 ends in the upper part of the seat 21, with the interposition of a corresponding dosage device, also designated by the reference numeral 18; said oil, appropriately metered according to the operating requirements, impregnates the annular felt 22. The dosage devices 18 are preferably of the needle type, and each one comprises a perforated and threaded tang 180 that screws into a corresponding threaded seat 190 of the body 19 (or of the distributor 15) and ends with a conical needle 181 that cooperates with a corresponding frustum-shaped tip cavity 191 of the seat 190; the axial movement of the threaded tang 180, which is produced by rotating said tang by means of a grip ring 182, is adapted to vary the gap L that lies between the needle 181 and the conical cavity 191 in order to throttle or, if necessary, interrupt the oil flow. A ring-shaped lock nut 183 screwed on the threaded tang 180 allows to lock the needle 181 in the selected adjustment position. The weft thread FT, in arriving from the spool 11, forms the balloon B, by means of which it rotates inside the holes 20 and 23, touching the internal surface of the latter hole and becoming impregnated with lubricating oil to an extent that is proportional to the degree of impregnation of the felt 22; said impregnation is in turn controlled by the dosage device 18. The excess oil, not absorbed by the weft thread FT, is collected by gravity by a corresponding discharge duct 24 that enters the lower part of the seat 21 and leads into a common collecting reservoir 25, in which all the discharge ducts 24a-24b...24n originating from the various lubricators 14a-14b...14n end. A pump 26 and a duct 26a are provided in order to recycle the oil from the collecting reservoir 25 to the supply reservoir 13, and level sensing means 27-28 are associated with the collecting reservoir 25 in order to activate and deactivate the pump 26 when the level in said reservoir reaches a preset maximum or, respectively, minimum level. Similar sensor means, at least of the minimum level sensing type, designated by the reference numeral 29, are provided in the supply reservoir 13 to activate at least one refill indicator 30, for example of the visual and/or acoustic type. Preferably, each lubricator 14 is completed, on the side where the weft thread FT enters, by a front shield 31 adapted to prevent the thread from becoming entangled in protrusions and the like due to the balloon B, and on the exit side, by a conventional brake 32 with facing disks which is adapted to tension the thread adequately. In installations having a limited number of lubricators 14, said lubricators can be cascade-connected to each other, so that the excess oil released by the lubricators 14b arranged at a higher level is fed by gravity to the lubricators 14b arranged at a lower level and is finally conveyed into the collecting reservoir 25. The different embodiment of figures 3 and 7 allows to provide a centralized lubrication system capable of feeding any number of lubricators with a constant and controlled flow-rate. This case can occur in creel structures formed by a plurality of modular elements that are assembled to supply a large pool of looms or other textile machines. In figure 3, the reference numeral 100 generally designates the modular element of a creel structure SC formed by two side-by-side rear posts 101 and two side-by-side front posts 102, all of which are interconnected by cross-members 103. A creel structure SC can be formed either by vertically overlapping a plurality of modular elements, such as 100' ... 100" etcetera, connected by joints 104, or by arranging horizontally and side-by-side identical modular elements that are interconnected by the cross-members 103 that cooperate with the joints 104. The rear posts 101 of each modular element support respective spools of thread 110-110' and the front posts 102 support a front shield 113, typically made of polymeric material, and preferably two lubricators 114-114' that are arranged side by side and downstream of the shield 113 with respect to the advancement direction of the thread FT that unwinds from the spools. A centralized oil reservoir 130 of substantial capacity, for example one hundred liters, is arranged adjacent to, and at the base of, a creel structure SC that is formed by a plurality of stacked and/or side-by-side modular elements 100, or said centralized reservoir is associated with a set of "n" creel structures, designated by the reference sign SC1...Scn in figure 7, that are adjacent to or even spaced from one another. A pressurized circuit is associated with the reservoir 130 and is adapted to supply a preset and constant flow-rate of oil to the individual lubricators 114-114' of each modular element 100 that composes each creel structure. The lubricators 114 can thus be arranged even at very different levels without this causing a difference in the flow-rate supplied thereto . Said flow-rate in fact no longer depends, as in the case of figure 1, on the hydraulic head, i.e., on the difference in level between the free surface of the oil in the reservoir 13 and each lubricator 14. Said pressurized circuit comprises at least one electric pump 140 that draws oil from the reservoir 130 and at least one delivery duct 141, from which branches 143-143' extend by means of cross-shaped unions 142, to feed the lubricators 114-114' of each modular element (figure 5), said branches being preferably made of polymeric material. By means of said cross-shaped unions 142, the delivery duct 140 reaches all the modular elements 100-100'-100" etcetera that compose each creel structure SC; the oil is also fed, by means of optional secondary ducts 141', to the various creel structures that compose a set of structures SC1...SCn as shown in figure 7. Advantageously, the oil supply pressure in the pressurized circuit is between 5 and 25 bar, according to the number of modular elements composing each creel structure and to the number of said structures combined so as to form a system. A recovery circuit cooperates with the above-described pressurized circuit and is provided with a corresponding unpressurized recovery duct 150, into which branches 151-151' merge which are also made of polymeric material, are connected to the corresponding lubricators 114-114', and are adapted to collect the excess oil discharged by said lubricators, and convey it into the duct 150 and into the centralized reservoir 130 by means of said duct. The recovery duct 150 reaches, by means of corresponding cross-shaped unions 152, all the modular elements 100 that compose the creel structure and, by means of secondary ducts 150', any other creel structures that compose the set SC1...SCn (figure 7). With reference now to figure 6, it is evident that each lubricator 114 is provided with a central body, generally designated by the reference numeral 219, that is formed by a first annular portion 220 of metal or metallic alloy that is chromium-plated and is provided with a funnel-shaped central hole 221 through which the thread FT passes; due to the balloon B, said thread rotates inside the hole and remains tangent to its surface. The first portion 220 is hermetically coupled, with the interposition of an O-ring 222, to a second portion 223 of the body 219 that is preferably made of polymeric material and in which a central hole 224 is formed; said hole is surrounded by an annular seat 225 for containing and retaining a felt ring 226. Two diametrically opposite radial ducts 227-228 lead into the seat 225 and end with respective seats for hermetically receiving, respectively, an automatic dosage device 229 that receives the corresponding branch 143 of the delivery duct 140, and a union 230 for connecting the corresponding branch 151 of the recovery duct 150. The automatic dosage device 229 in turn comprises a cylindrical body with a first threaded tang that screws into the respective seat of the portion 223 of the body of the lubricator and a second threaded tang that receives a ring 231 for the hermetic connection of the branch 143. Said hermetic connection is provided, in a per se known manner, with the interposition of a connecting ring 232 that is shaped like a double frustum and cooperates with a spacer ring 233 that has a frustum-shaped seat adapted to hermetically accommodate one end of the connecting ring 232. A filter 234, preferably composed of agglomerated spheres, is accommodated below the ring 233 and has the purpose of filtering any impurities that are present in the oil. A cylindrical seat is formed in the body of the dosage device 229, and the stem of a shutter 237 is slideable in said seat with a considerable radial clearance and in contrast with the action of a spring 235 that pushes against a spacer 236; the shutter is provided with a frustum-shaped head 238 that cooperates with a valve seat that is also correspondingly frustum-shaped and is provided in said dosage device body. The radial clearance between the stem of the shutter and the respective containment seat, as well as the rigidity of the spring 235, are chosen so as to allow the passage of a preset flow-rate of oil to appropriately impregnate the felt ring 226; said flow-rate is, for example, between three and eighty drops per minute. Any excess oil that is not absorbed by the thread is released by the felt 226 into the radial duct 228 to be collected by the branch 150 and conveyed into the reservoir 130. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims: A weft thread lubrication device for textile machines, particularly weaving looms and the like, comprising: an oil supply reservoir (13-130) which by means of respective delivery ducts (17-141-142) distributes the oil to a plurality of individual lubricators (14-114) arranged in front of respective spools (11-110) of weft thread (FT) supported by a creel structure (10-100), and recovery means (24-25-151) that receive the excess oil from said lubricators (14-114) to recycle it into the oil supply reservoir (13-130) characterized in that each lubricator has an annular felt (22-226) that is impregnated by said oil and is crossed by the weft thread which, by virtue of an unwinding balloon (B) adheres to the inner surface of the axial hole of said felt, absorbing the oil; a distributor (15) and individual dosage devices (18) being associated with said distributor and/or with said lubricators (14), and in that the upper part of said annular seat (21) of each dosage device (18) is connected to a respective oil delivery duct (17) by means of the dosage device (18), and in that the lower part of the seat (21) is connected to a respective discharge duct (24) ending in the recovery means (25). The device according to claim 1, characterized in that the supply reservoir (13) supplies the oil by gravity to said lubricators (14) and is supported by the creel structure (10) at a higher level than the uppermost row of spools (11b) of weft thread, and in that the recovery means comprise a recovery reservoir (25) that is arranged at the base of the creel structure (10) and pumping means (26) that are adapted to periodically recycle the oil from the recovery reservoir (25) to the supply reservoir (13). The device according to claim 1, characterized in that the capacity of the supply reservoir (13) is at least between 10 and 25 liters. The device according to claim 1, characterized in that said supply reservoir (13) feeds the oil by gravity to the individual lubricators by means of said distributor (15) and of said individual dosage devices (18) that are associated with said distributor and/or with said lubricators (14). The device according to claim 1, characterized in that an electric valve (16) is interposed between the oil supply reservoir (13) and the distributor (15) and is adapted to interrupt the oil supply stream. The device according to claim 1, characterized in that each lubricator (14) comprises a rigid body (19) that is provided with a funnel-shaped front hole (20) through which the weft thread (FT) passes, and in that the largest cross-section of the funnel-shaped hole is directed towards the spool (11) of thread and the smallest cross-section is adjacent to an annular seat (21) containing the corresponding annular felt (22). The device according to claim 1, characterized in that the dosage devices (18) associated with the distributor (15) and/or with the individual lubricators (14) are manually regulated and of the needle type, and in that each one comprises a perforated and threaded tang (180) that screws into a respective threaded seat (190) and ends with a frustum-shaped needle (181) that cooperates with a corresponding frustum-shaped cavity (191) of said seat; the axial movement of the tangs (180) being adapted to vary the gap (L) between said needle (181) and said frustum-shaped cavity (191) in order to throttle and/or interrupt the oil flow. The device according to claim 2, characterized in that the recovery reservoir (25) comprises level sensing means (27-28) that are capable of activating and deactivating the recycling pumping means (26) when the level of the oil in said reservoir reaches a preset maximum or, respectively, minimum value. The device according to claim 1, characterized in that the oil supply reservoir (13) comprises sensor means (29) that detect at least the minimum level and are capable of activating a refill indicator (30). The device according to claim 1, characterized in that each lubricator (14-114) comprises, on the side where the weft thread enters, a front shield (31-113) for said thread. The device according to claim 1, characterized in that the individual lubricators (14) are cascade-connected so that the excess oil released by the lubricators (14b) arranged at a higher level feeds the lubricators (14a) located at a lower level. The device according to claim 1, characterized in that it comprises a pressurized supply circuit including at least one electric pump (140) that is adapted to feed pressurized oil to at least one delivery duct (141), from which branches (143-143') extend that feed the oil to corresponding pairs of lubricators (114-114'), and a recovery circuit that is provided at least with a respective unpressurized recovery duct (150) into which branches (151-151') connected to said lubricators merge, said branches collecting the excess oil released by said lubricators and conveying it to a centralized collection reservoir (130) from which the suction duct of said electric pump (140) draws. The device according to claim 12, characterized in that said pressurized delivery duct (141) and said unpressurized recovery duct (150) reach a plurality of modular elements (100-100'...100") that compose a creel structure (SC), each element comprising two lubricators (114-114') that are arranged adjacent to a corresponding pair of thread spools (110-110'). The device according to claim 13, characterized in that said pressurized delivery duct (141) and said unpressurized recovery duct (150) reach, by means of respective secondary ducts (141'-150'), a plurality of creel structures (SC1...SCn) that compose a set. The device according to claim 13, characterized in that the pressurized delivery duct (141), together with its respective branches (143-143'), and the unpressurized recovery duct (150), together with its respective branches (151-151'), are constituted by pipes made of polymeric material. The device according to claim 13, characterized in that the pressure of the oil in said pressurized supply circuit is between 5 and 25 bar. The device according to claim 15, characterized in that each lubricator (114) comprises an automatic dosage nozzle (229) that is located at the inlet of the branch (143) of the supply circuit, said nozzle comprising a stem-shaped shutter (237-238) that is contrasted by a spring (235) the rigidity whereof is calculated as a function of the operating pressure of said supply circuit in order to allow a preset flow-rate of oil to pass, said flow-rate being between three and eighty drops per minute.

Inventors: PEDRINI GIOVANNI, ZENONI PIETRO, PEDRINI, GIOVANNI, ZENONI, PIETRO
Applicants: LGL ELECTRONICS SPA, L.G.L. ELECTRONICS S.P.A.
Application year: 1996
Main classification: D03J1
IPC codes: D03J1