FR2524451A1 - Loom weft yarn store - has grooved ring around store drum with elastic ring feeler - Google Patents

Abstract

A fixed outer ring (10) covers the yarn store drum (8) with a gap between them, and it is fitted with a radial groove (10a), to form the yarn store assembly in the weft feed system for a loom. The conductive feeler is at least one elastic ring (9) sitting freely in the groove (10a) of the outer ring (10), pressing against the yarn store drum (8). The assembly gives a positive register of the yarn in the yarn store, and prevents false signals being sent to the loom stop mechanism.

Description

 The present invention relates to weaving; more specifically to weaving looms with a fixed weft thread spool, and in particular relates to a device for forming a reserve of thread when it is inserted into the crowd of a weaving loom.

 A device is known for forming a reserve of thread during its insertion into the crowd of a weaving loom comprising a drum for forming a reserve of thread, a rotating thread guide and a member sensitive to the presence of the thread (cf., for example, USSR patent NO 406370, cl.

D 03 D 47/34).

 In this device, the quantity of coiled wire turns is controlled using a photoelectric cell mounted above the cylindrical part of the drum.

 The photoelectric cell controls the rotation of said wire guide as a function of the number of coiled wire coils, constantly maintaining a predetermined number of coils on the drum. Such a wire reserve formation device employing a photoelectric cell as an organ sensitive to the presence of the wire is insufficiently reliable, given the risk of dusting of the cell.

 In the device considered, in order to facilitate the unwinding of the wire by limiting its bloating during its unwinding of the drum, an appropriate annular element in the form of a cone can be used which can move axially and is mounted with a clearance relative to the part d 'reduced diameter end of the drum. In such a device, during the unwinding of the drum thread, the passage through said set of knots and extra thicknesses of the thread results in a significant overvoltage of the latter, causing it to break during its insertion into the crowd of the craft. In addition, such an annular element does not ensure the limitation of the bloating of the wire in the zone of the initial turns during the unwinding of the wire, which leads to the formation of loops in the fabric and lowers the quality of the latter.

In order to improve the operating reliability of the member sensitive to the presence of the wire, in a similar device which is the subject of the patent application
RFA Rendered Ap7blique NO 2335204, cl. D 04 B 15/48, for the control of the number of turns of wire wound on the drum, a feeler is applied elastically applied against the drum so as to ensure punctual mechanical and electrical contact with the latter, this feeler being able to move relative to the drum generator. The feeler has a V shape. In such a device, when winding a determined number of turns of wire on the drum, the feeler is moved axially by the turns of wire while pivoting about its fixing axis. The displacement of the V-shaped feeler cuts the electrical connection between the drum and the block controlling the rotation of the thread guide, which stops the process of winding the thread on the drum. Subsequently, during the unwinding of the drum wire, the electrical connection between the drum and the control unit is re-established and the winding of the wire on the drum begins again. In such a device, the electrical connection of the drum with the control block for the rotation of the thread guide is only ensured at the single point where the feeler touches the surface of the drum, hence the risk of device failure. because of the oxidation of the almost point contacting faces or else of the presence of a stain between the feeler and the surface of the drum.

In addition, in such a device, the wire unwinding from the drum, passing through the point where the feeler touches the drum, cuts the electrical contact between the feeler and the drum, so that the motor actuating the rotating thread guide does not is temporarily more energized, the speed of rotation of the wire guide suddenly decreases, which alters the process of winding the wire on the drum and cause a break in the wire.

 The periodic passage of the thread through the point of contact between the feeler and the drum also temporarily increases the tension of the thread, which favors the appearance of an additional irregular tension of the thread and leads to an increase in the number of breaks in the thread. during its insertion into the crowd of the loom. During the operation of the device in question, the bloating of the wire around the drum can cause the said wire to be hooked by the V-shaped feeler and consequently to break.

 The present invention therefore relates to a device for forming a wire reserve? during its insertion into the crowd of a loom, whose feeler would be designed so as to ensure permanent contact with the surface of the drum, thus excluding the risk of application to the control unit of false signals causing the disconnection of the thread guide rotation control.

 This problem is solved with the aid of a device for the formation of a reserve of thread when it is inserted into the crowd of a loom, of the type comprising a fixed drum made of current-conducting material for the formation of the wire reserve, a wire guide mounted mobile in rotation around said drum and a feeler of current-conducting material for controlling the number of turns of wire, mounted so as to contact the surface of said drum and electrically connected to a block of motor control rotating the wire guide, said device being characterized, according to the invention, in that it also comprises an annular support embracing the drum for forming the reserve of wire, said support being mounted fixed and with a certain interval with respect to said drum and having a radial notch, said feeler being produced in the form of at least one elastic ring placed freely in the notch of the annular support and elastically enclosing the 'format drum Wire reserve ion along its periphery.

 It is advantageous that the elastic ring is constituted by a tension spring and that the interval between the drum for forming the wire reserve and the annular support is commensurable with the thickness of the wire.

 The execution of the feeler in the form of at least one elastic ring elastically embracing the peripheral surface of the drum makes it possible to ensure linear electrical contact of the feeler with the drum over the entire area of application of the elastic ring against the drum. , which increases the reliability in service of the device. At the same time, the use of such a feeler makes it possible to obtain a permanent electrical connection between said guardian and the drum during the unwinding of the latter's thread, which ensures a regular and continuous winding of the thread on the drum during the insertion of the thread into the crowd of the loom, which improves the process of forming the reserve of thread and decreases the number of breaks of thread.

 In such a device, the unwinding of the weft thread from the drum when it is inserted into the crowd of the weaving loom occurs without bloating in the unwinding zone of the initial thread turns, since the thread being unwound is in interaction permanent elastic with the elastic ring and with the surface of the drum.

This elastic interaction between the thread and the elastic ring during its unwinding or drum ensures the maintenance of a constant tension of the thread during its insertion in the crowd of the loom, which excludes the formation of loops in the fabric and improves the drum thread unwinding process as well as the quality of the fabric produced. In such a device, the passage of the knots and the excess thicknesses of the thread during its unwinding in the zone of application of the elastic element against the drum only causes an insignificant increase in the tension of the thread, not leading to its broken.

 The fixing of the electroconductive element in the annular support, preventing any axial displacement of this elastic ring, makes it possible to maintain a determined constant number of turns of wire on the drum during the operation of the device.

 Such a device for forming a reserve of thread makes it possible to improve the process of unwinding the thread of the drum and excludes the need to use an auxiliary member to reduce the bloating of the thread.

The invention will be better understood and other objects, details and advantages thereof will appear better in the light of the explanatory description which will follow of different embodiments given only by way of nonlimiting examples, with references to the drawings. nonlimiting annexed in which
- Figure 1 shows a general schematic view of a device for the formation of a reserve of thread during its insertion into the crowd of a loom (longitudinal section)
- Figure 2 shows an elastic ring made in the form of a tension spring
- Figure 3 shows an elastic ring in the form of two tension springs.

 In the casing 1 (FIG. 1, 2) of the device for forming a wire reserve is mounted a stator 2 of an electric motor carrying windings 3, as well as a hollow wire guide 4 mounted on rolling bearings 5.

A rotor 6 rotating the wire guide 4 is rigidly fixed to the latter. On the wire guide 4 is fixedly mounted, by means of a rolling bearing 7, a drum 8 for forming a wire reserve, made of a current conducting material. On the drum 8 for forming the wire reserve, along its entire periphery, is applied elastically a feeler made of current-conducting material executed in the form of at least one elastic ring 9.

 The device for forming the wire reserve comprises a fixed annular support 10 rigidly fixed to the casing 1 and consists of a current conducting material.

The support 10 is fixed with a certain interval relative to the surface of the drum 8 for forming the reserve of thread, in the zone of application of the elastic feeler 9, and has a radial notch 10a in which is housed said elastic ring 9 The notch 10a is formed by two rings 11 and 12 preventing the axial movement of the elastic ring 9.The value of the interval between the drum 8 for forming the wire reserve and the annular support 10 is chosen commensurable with the thickness of the wire, which allows this wire to pass freely under the support towards the elastic ring 9.

 The elastic ring 9 can be manufactured either in the form of a current conducting rubber cord, either in the form of a tension spring 9a (figure 2), or alternatively, it can comprise two tension springs 9b (figure 3) in the form of two half-rings as shown in FIG. 3. The elastic ring 9 (FIG. 13 is placed in the notch 10a of the annular support 10 so as to be able to move freely in the radial direction, throughout the area of its application against the drum 8, between the two rings 11 and 12. The elastic ring 9 and the support 10 form a device sensitive to the presence of the wire and used to control the number of turns of the wire 13 on the drum 8 and to maintain a predetermined number of these turns on the drum 8.

 The elastic ring 9 and the drum 8 are electrically connected to a block 14, of a type known per se, for controlling the rotation of the wire guide 4, for the transmission of an electrical signal carrying information on the presence on the drum 8 with a number of turns less than or equal to the assigned value and for the subsequent transformation of this signal into a thread guide rotation movement 4 or the cessation of its rotation, depending on the character of said signal .

 The proposed device operates as follows.

 The wire 13 arrives in the cavity of the wire guide 4 and when the supply voltage is applied to the windings 3 of the stator 2 of the electric motor, this wire is wound on the drum 8 to form a reserve of wire by the guide -wire 4 in rotation. Said drum is immobilized in rotation by any known means, for example using a weight (not shown). The turns of the wire 13, during its winding on the drum 8, advance along its axis towards the elastic ring 9 and, on reaching it, move it away from the surface of the drum 8, thereby cutting the electrical connection between the ring 9 (the feeler) and the drum 8, so that the block 14 cuts off the supply of the windings 3 of the stator 2 of the electric motor, the wire guide 4 stops rotating and winding the wire 13 on the drum 8. The movement of the wire turns along the axis of the drum 8 is carried out using any known means, for example using a conical projection 15 of the drum 8, as shown on Figure 1. When inserting the thread into the crowd of the loom, this thread is unwound from the drum 8 and the elastic ring 9 is applied again to the drum 8 thereby re-establishing the electrical connection between them. The block 14 then again applies a supply voltage to the winding 3 and the wire guide 4 begins to rotate and to wind the wire 13 on the drum 8. Then the operating cycles are repeated. rolling bearings 5 and 7 would not ensure secure electrical contact between the drum 8 and the casing 1 of the device for forming the wire reserve, the device sensitive to the presence of the wire consists of two elastic half-rings, for example of springs 9b as shown in FIG. 3. In this case, the two elastic half-rings are separately electrically connected to the block 14 for controlling the rotation of the wire guide 4 and are electrically connected to each other via the drum 8.

 Thus, the fact that the member sensitive to the presence of the wire comprises an elastic ring of electrically conductive material embracing the drum 8 for forming a wire reserve along its periphery and elastically applied against this drum increases the reliability of the operation of the device. for forming the wire reserve thanks to the electrical connection of the block 14 for controlling the rotation of the wire guide with the drum 8 along the line of application of the elastic ring 9 against this drum 8.

 The use of a feeler in the form of an elastic ring in the organ sensitive to the presence of the wire improves the processes of accumulation of the wire on the drum and of unwinding of this wire from the drum, which reduces breakage. weft thread and increases the quality of the fabric obtained.

Claims (3)

 1.- Device for the formation of a reserve of thread during its insertion into the crowd of a loom, of the type comprising a drum (8) for the formation of a reserve of thread, mounted fixed and constituted by a current conducting material, a wire guide (4) movable in rotation around the drum (8) for forming a wire reserve, and a feeler constituted by a current conducting material, intended to control the number of turns of wire wound on the drum (8, and mounted so as to be able to contact the surface of the drum (8), said feeler being electrically connected to a block (14) for controlling the motor rotating the wire guide (4), characterized in that it comprises a fixed annular support (10) embracing the drum (8) for forming a reserve of wire, separated from said drum by an interval and having a radial notch (10a), said feeler being produced in the form of at least one elastic ring (9) placed freely in the notch (10a) of the annular support (10) and e Elastically tightening the drum (8) along its periphery.  2.- Device according to claim 1, characterized in that the elastic ring (9) is constituted by a tension spring (9a).  3.- Device according to one of claims 1 and 2, characterized in that the interval between the drum (8) and the annular support (10) is commensurable with the thickness of the wire.