Apparatus for recovering thread loops in warping machines

Abstract: System for recovering thread loops in warping machines with a support for winding up the thread in a preset sequence and with means for presenting and releasing the same threads, the apparatus comprising a fixed structure (1) located between a warper and a creel on which reels are provided for feeding the threads (F, G, H, ...., Z) to the warper (2), wherein to said structure (1) means are associated which impart an impulse, from above downwards, to the thread each time disengaged by the release members (21) of the warper (2): said means acting upon the portion of thread between the structure (1) and the warper (2) and being connected to the release members (2) so that the impulse is imparted simultaneously to the release of the thread.

Description: The present invention refers to a system for recovering thread loops in warping machines. Warpers are known in which warps are prepared by the so-called "thread-by-thread" system, that is, by only one thread at a time, according to a sequence which is preset on the basis of the programmed warping pattern. Currently, the most widespread warpers performing this work are essentially of two types: the Suzuki-type warpers and the Hergeth-type warpers. The Suzuki warpers are provided with a fixed cylindrical support or "drum" having horizontal axis on which each thread is wound with the aid of a thread-holding rod rotating about the drum axis. The turns so formed upon every revolution of the said rod are progressively moved away from their deposition site by means of driving belts ring-like developed parallel to the drum axis on the outer length of which said turns are laid. In the Hergeth-type warpers, the support of the turns is made up of an array of belts closed over two horizontal drums suitably spaced apart so that the support for the turns in the process of formation is substantially vertical instead of being cylindrical with horizontal axis. The individual working threads are borne by a movable hook connected to a belt which closes up over said horizontal drums. The Hergeth-type warpers also exhibit means for the progressive moving away of the turns from their deposition site. Provided in both the above described warpers are means for feeding threads from corresponding reels arranged on a creel, means for presenting the threads to the rod or thread-holding hook and means to operate, under control, the release of the working thread for its return in the corresponding presentation channel at the base of the warper, said release means being placed in fixed position with respect to the threads-presentation channels. When the thread is released - and owing to the fact that the release means are at a distance from the respective presentation channel - the thread forms a loop, in the region between the release means and said channel, whose length increases with the distance of the channel from the release means. Because of the operational sequence typical of these machines, it is necessary to wait for the return of the loop formed by the release of a thread before taking out the next thread and winding it over the drum (or over the vertical belts) of the warper. To allow for the return of this loop, each thread is made to slide through a perforated disc mounted on vertical guides to enable it to move by gravity between a lifted position, corresponding to the condition in which the thread is used for the warping, and a lowered position, corresponding to the condition in which the thread is not used and ready for its hooking up. During the loop-recovery stage, the disc moves from the top to the bottom position. The return speed of the loop depends, therefore, only on the weight of the discs, weight which cannot be increased beyond a certain value in order not to overstress the working threads - this being a heavy restraint to the operational capacity of the warpers. The main object of the present invention is to overcome the said drawback. This result has been achieved, according to the invention, by providing a system having the features indicated in the characterizing part of the independent claims. Further characteristics being set forth in the dependent claims. The advantages deriving from the present invention lie essentially in that it is possible to significantly reduce the time for recovering the loop formed by the release of the threads on the warper, thereby reducing the time for waiting the return of the threads in the respective presentation channels, this making it possible, any other condition being equal, to increase the production, without overstressing the threads, of both warpers with horizontal drum and of warpers with vertical drum, that is, of Hergeth type; that an apparatus according to the invention is simple to make, cost-effective and reliable even after a prolonged service life. These and other advantages and characteristics of the invention will be best understood by anyone skilled in the art from a reading of the following description in conjunction with the attached drawings given as a practical exemplification of the invention, but not to be considered in a limitative sense, wherein Fig. 1 is a schematic perspective view of an apparatus, according to the invention, associated to a vertical warper of Hergeth type, which shows the thread-presentation channels, the thread-holding hook and the member which allow the release of the threads as necessary for their changeover; Fig. 2 shows a further embodiment of the apparatus, according to the invention, ideally separated from the warper; Fig. 3A is a simplified block diagram of the means for driving the arms of the apparatus of Fig. 1; Fig. 3B is a block diagram similar to that of Fig. 3A for the apparatus of Fig. 2. Reduced to its basic construction, an apparatus according to the invention comprises a fixed structure (1) located between a warper and a creel - not shown for the sake of simplicity - on which reels are provided for feeding the threads (F, G, H, ...., Z) to the warper (2) and on which means are installed able to impart an impulse, from above downwards, to the thread each time disengaged by the release members (21) of the warper (2): said means acting upon the portion of thread between the structure (1) and the warper (2) and being connected to the release members (2) so that the impulse is imparted simultaneously to the release of the thread. With reference to Fig. 1 of the attached drawings, the said means comprise, for each thread, an arm (3) oriented toward the warper (2) and angularly oscillating between a lifted position, corresponding to the condition in which the thread is wound on the warper, either on the point of being released or standing by for its removal (like the threads F, G and Z of Figs. 1 and 2) and a lowered position, corresponding to the condition of loop return after the release of the thread (like the thread H of Figs. 1 and 2): the free end of each arm (3), or any other portion thereof, having the function of intercepting the respective thread in order to impose a corresponding downward movement to the portion thereof that results between the structure (1) and the warper (2) once the same thread is released from the thread-holder (22). Advantageously, the free end (30) of each arm (3) may be shaped like a hook through which the thread is made to pass. In order to drive the arms (3) into rotation a plurality of corresponding solenoid motors (31) or equivalent means may be employed which are operable in parallel with the release member (21) via a programmable electronic control unit (UE), according to the diagram of Fig. 3A, which may be the same unit already present in the warpers and intended to control the presentation and the release of the threads in accordance with the programmed warping pattern. The control units of the warpers are known per se to those skilled in the art and, therefore, will not be described in further details. The said solenoids (31) may be fixed to respective bearing brackets (32) which are, in turn, connectable to a fixed part of the structure (1). The connection of the brackets (32) to the structure (1) may also be carried out by screw means (35) - of which Fig. 1A shows but a trace for the sake of simplicity - in order to adjust the height of the same brackets as necessary to meet any application requirement. In place of an arm (3) for each thread, a single longer arm for all the threads may be provided. Advantageously, according to the invention, to said structure (1) a horizontal rod (34) is associated in a position facing the free end of the arms (3) to make up a stop element for the downward travel of the threads acted upon by the same arms (3). Moreover, advantageoulsy, the rod (34) is supported by a pair of vertical elements (35) - only one of which being shown in Fig. 1 - each of which is disposed on a corresponding side of the structure (1) and provided with a seat (350) for receiving the corresponding end of the rod (34) to allow the latter to be located at a plurality of different heights with respect to the set of members (23) which present the threads into the channels (24) of the warper (2). The threads to be fed to the warper may be made to pass also through perforated discs (33) lighter than those in use in the existing warping systems. According to a further embodiment, and reference being made to the attached drawings, the means intended for downwardly imparting the impulse to the thread upon its release comprise, for each thread to be fed to the warper (2), a cylindrical chamber (4) associated to an electrical aspirator (40) and intended to act as a vertical guide for a corresponding hollow ball (41) - or a ball of lightweight material - to which a ring (42) is fixed for the thread to go therethrough. Each of the chambers (4) may be put into comunication with the aspirator (40) via a conduit (46) to which the lower open base of each chamber (4) is connected through a communication port (48). While any of the said threads is being wound on the warper, the draw exerted by the thread-holding member (22) is such as to cause the maximum lift of the corresponding ball (41) inside the respective chamber (4). In this stage, the aspirator (40) is deactivated and no draw is exerted on the other threads and, accordingly, the respective balls (41) occlude the port (48) which puts into communication the conduit (46) with the corresponding chambers (4). When the thread already in the process of being wound is released, no draw is exerted on it and, by activating the aspirator (4) concurrently with the release, the respective ball (41) is called back downwards - as indicated by the arrows of Fig. 2 - until it occludes the corresponding port (48) of conduit (46). As soon as the thread-holding member (22) withdraws a new thread from the presentation members (23), the aspiration is switched off. Advantageously, to ensure an even more stable vertical guide, each of said rings (42) is fixed to the lower end of a vertical rod (43) made of lightweight material, such as plastics, sliding within a corresponding guide hole (44) formed in a horizontal fixed cross-piece (45) disposed above the chambers (4). A fixed rod (47) developing trasverse to and above the said chambers (4) may be provided to make up an upper stop element for the upward travel of the threads acted upon by the apparatus. Also in the case of the embodiment described with reference to Fig. 2 of the attached drawings, the control of the aspirator may be operated by the electronic unit (UE) which controls the various operational stages of the warper, as schematically illustrated in Fig. 3B. With reference to both the embodiments above described, the instantaneous lowering outside the warper imparted to the thread upon its release stage (transfer from position Z to position H of Figs. 1 and 2), will cause the recovery or return of the loop formed by the same thread when this is released by the member (21), the latter being actuated to intercept the thread, driven into rotation on the warper by the thread-holding member (22), and disengage it. The system according to the present invention implies, therefore, an action, to be exerted on the released thread, in such a manner to allow for the subsequent translation of its portion located between the warping machine and the feeding unit towards the latter. Although Fig. 1 illustrates an embodiment for application to a vertical warper, the operation of the present apparatus is the same as in the case of a warper with fixed drum having horizontal axis. In Fig. 1, numerals (23) and (24) indicate the whole of members and, respectively, the presentation channels in correspondence of the warper (2). These means, known per se to those skilled in the art, as well as the curved guide (25) intended to guide, in correspondence of the presentation channels (24), the thread being wound of the warper (2), do not require any modification for the application of the present apparatus.

Claims: Apparatus for recovering thread loops in warping machines with a support for winding up the thread in a preset sequence and with means for presenting and releasing the same threads, the apparatus comprising a fixed structure (1) located between a warper and a creel on which reels are provided for feeding the threads (F, G, H, ...., Z) to the warper (2), characterized in that to said structure (1) means are associated which impart an impulse, from above downwards, to the thread each time disengaged by the release members (21) of the warper (2): said means acting upon the portion of thread lying between the structure (1) and the warper (2) and being connected to the release members (2) so that the impulse is imparted simultaneously to the release of the thread. Apparatus according to claim 1, characterized in that the means, intended to impart an impulse to the threads upon their release, are operable under control of an electrical signal and are electrically connected to said release members (21). Apparatus according to claims 1 and 2, characterized in that said means comprise, for each thread, an arm (3) oriented toward the warper (2) and angularly oscillating between a lifted position and a lowered position: a portion of each arm (3) having the function of intercepting the corresponding thread in order to impart, to the portion thereof lying between the structure (1) and the warper (2), a corresponding downward movement upon its release from the thread-holder (22). Apparatus according to claim 3, characterized in that the free end (30) of each arm (3) is shaped like a hook through which the thread is made to pass. Apparatus according to claim 3, characterized in that it comprises, in order to drive the arms (3) into rotation, a plurality of corresponding solenoid motors (31) operable in parallel with the reales member (21) of the warper (2). Apparatus according to claims 3 and 5, characterized in that said solenoids (31) are fixed to respective bearing brackets (32) which are, in turn, connected to a fixed part of the structure (1). Apparatus according to claim 1, characterized in that said means consist of a single arm developed transverse to the threads and associated to a corresponding driving member. Apparatus according to any of claims 1 to 7, characterized in that said structure (1) is associated to a horizontal rod (14) positioned opposite to the free end of the arms (3) in order to make up a stop element for the downward travel of the threads acted upon by the same arms (3). Apparatus according to claim 8, characterized in that said rod (34) is supported by a pair of vertical elements (35), each of which is located on a side corresponding to the structure (1) and provided with a seat (35) for receiving the corresponding end of the rod (34) to allow the latter to be located at a plurality of different heights with respect to the set of members (23) which present the threads into the channels (24) of the warper (2). Apparatus according to claim 1, characterized in that the means intended for downwardly imparting the impulse to the thread upon its release comprise, for each thread to be fed to the warper (2), a cylindrical chamber (4) associated to an electrical aspirator (40) and intended to act as a vertical guide for a corresponding plug (41) to which a ring (42) is fixed for the thread to go therethrough: said plug (41) having the function of opening, respectively, closing a port allowing the chamber (4) to communicate with a conduit (46) connected with the aspirator (40). Apparatus according to claims 1 and 10, characterized in that each of said rings (42) is fixed to the lower end of a vertical rod (43) sliding within a corresponding guide hole (44) formed in a horizontal fixed cross-piece (45) disposed above the chambers (4). Apparatus according to claims 1, 10 and 11, characterized in that it comprises a fixed rod (47) developing trasverse to and above the said chambers (4) to make up an upper stop element for the upward travel of the threads. Method for recovering thread loops in warping machines, characterized in that , in correspondence of the releasing step of a thread at the end of the relevant winding step, the portion of said thread which is the area included between the warping machine and and the corresponding feeding unit is subject to a translation towards the thread feeding unit.

Inventors: VIERI ROBERTO, VIERI, ROBERTO
Applicants: AGE S N C DI VIERI A & C, AGE S.N.C. DI VIERI A. & C.
Application year: 1998
Main classification: D02H3
IPC codes: D02H3