US3223351A

US3223351A - Thread tension regulator for textile machines

Info

Publication number: US3223351A
Application number: US347451A
Authority: US
Inventors: Lemarchand Francis
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-03-15
Filing date: 1964-02-26
Publication date: 1965-12-14
Anticipated expiration: 1982-12-14
Also published as: FR83273E

Description

1965 F. LEMARCHAND 3,223,351

THREAD TENSION REGULATOR FOR TEXTILE MACHINES Filed Feb. 26, 1964 2 Sheets-Sheet 1 INVENTOR B7 FRANCIS LEIIHRGll/IND WM W Dec. 14, 1965 F. LEMARCHAND 3,223,351

THREAD TENSION REGULATOR FOR TEXTILE MACHINES Filed Feb. 26, 1964 2 Sheets-Sheet 2 -H H 47 4g INV'EMTOR FRHNC! 5 LEMRRCll/W r MW/M W,

United States Patent 6 Claims. hi. 242-154 The present invention relates to thread tension regulators for textile machines such as, for example, creels, reeling machines, spoolers, winders, false-twist machines, etc.

In the majority of thread tension regulators, the braking of the thread is effected by means of one or a number of devices comprising discs so designed that the clamping action thereof increases the tension of the thread on the output side of the regulator. When using devices of this type, a deposit rapidly forms on the discs as a result of the passing of the thread between these latter and calls for frequent dedusting either manually or by compressed air, as otherwise the regulator would not work under satisfactory conditions.

In other known types of regulators, the braking of the thread is effected by modifying the path of this latter so as to cause tension by producing a variation in the lengths of the are over which the thread is wound around two cylinders which can be either movable or stationary. These regulators usually comprise a pivotal feeler system which is subjected to the action of a balance weight. \Vhen the speed of movement of the thread is high and, in a more general manner, when the frequency of variations in thread tension is high, the inertia of the balance weight adversely affects the stability of tension regulation. There frequently take place disturbing pulsations which are a source of difficulties in the design of tension regulators of this type, inasmuch as such pulsations are liable to result in damage to the thread.

Finally, tension regulation devices are also known which comprise grids or traveling rings, that is to say threadbraking devices having a large number of points of friction. In the case of devices of this type, it is diflicult to ensure accurate and progressive tension regulation. Furthermore, in order to balance the thread tension at a number of dilferent points along its path, it is necessary to apply a relatively substantial amount of power. If such power is provided by a balance weight, the inertia of this latter is detrimental to the good working of the regulator, and if this power is supplied by an electromagnet of the linear action type, the power consumption thereof is relatively high.

The object of this invention is to provide a thread tension regulating device for textile machines which is not subject to the above-mentioned disadvantages of known devices.

To this end, the thread tension regulator in accordance with the present invention comprises in combination: a stationary inlet thread guide, a stationary convex shoe having a varying radius and preferably having the shape of a portion of ellipse, a single movable thread guide and a stationary outlet thread guide, against each of which in turn the thread whose tension is to be regulated is intended to pass, the combined assembly and especially the configurations and relative positions of the stationary shoe and of the path of the movable thread guide being so designed and arranged that, when the movable thread guide moves in one direction along its path under the action of suitable resilient means such as an electromagnetic force which opposes the action produced by the thread tension on said movable thread guide, this latter produces an increase in the length of the arc of the shoe against which the thread rubs, whereas said movable thread guide brings about a reduction in the length of said are when performing a movement in the opposite direction under the predominant action of the thread tension.

A thread tension regulator of this type is of extremely simple constructional design, makes it possible to obtain a very uniform thread tension which can be accurately adjusted to a pre-determined value and which does not call for frequent servicing operations either for the purpose of cleaning, maintenance or re-adjustment.

One object of the invention is to provide a tension regulator wherein the movable thread guide is mounted at the free end of a lever-arm which is preferably balanced and the weight of which is as light as possible whilst the other end of said leverarm is capable of pivoting about a shaft which is at right angles to the place of the convex profile of the shoe.

Another object of the invention is to provide a tension regulator wherein the general characteristics of the apparatus including the characteristics of the means which apply a restoring force to the movable thread guide are such that, in any angular position of the lever-arm which carries the movable thread guide, the torque which is exerted on said lever-arm by the restoring means is equal to the torque exerted thereon by the thread tension applied to said movable thread guide.

Yet another object of the invention is to provide a tension regulator wherein the lever-arm which carries the movable thread guide is subjected to a constant restoring torque which is preferably supplied by an asynchronous motor of the type known as a torque motor, and the design of the combined assembly is such that the resultant of the tension oft he run of thread which arrives against the movable thread guide and of the tension of the run of thread which passes out of this latter accordingly exerts on the lever-arm which carries said movable thread guide a substantially constant torque having a value which is approximately equal to that of the restoring torque.

Again another object of the invention is to provide a tension regulator wherein the resilient means for returning the movable thread guide are pneumatic means.

A further object of the invention is to provide a tension regulator wherein the movable thread guide is coupled to a movable partition wall, one face of which is subjected to atmospheric pressure whilst the other face is subjected to the pressure of a suitable source of fiuid under constant pressure.

Again a further object of the invention is to provide a tension regulator wherein the movable partition wall consists of a vane which is pivotally mounted inside a sealed casing having the shape of a circular arc in which said vane forms two chambers which are respectively in communication with the atmosphere and with the source of fluid under constant pressure.

Another object of the invention is to provide a tension regulator wherein the movable partition wall is constituted by the flexible base of a capsule, the interior of which is in communication with the source of fluid under constant pressure.

The invention will be more readily understood by perusal of the following description and by examination of the accompanying drawings which show, by way of example, a few forms of embodiment of thread tension regulators for textile machines according to the invention.

In these drawings:

FIG. 1 is a front view of one form of embodiment electric motor;

FIG.- 2 is a profile v1'ew corresponding to FIG. 1;

FIG. 3 is a front view of another form of embodiment of regulator wherein the restoring torque is supplied by a pneumatic system comprising a pivoting vane;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, the pivoting vane being assumed to be brought back on the plane of the section;

FIG. 5 is a sectional view taken along line V-V of FIG. 4;

FIG. 6 is a sectional view taken along line VI-VI of an alternative form of regulator wherein the restoring torque is supplied by a manometric capsule;

FIG. 7 isra sectional view taken along line VI1VII of FIG. 6.

The thread tension regulating device for a textile machine as shown in FIGS. 1 and 2 comprises a casing 1, on one face of which (designated hereinafter as the front face) are fixed a stationary inlet thread guide 2, a stationary outlet thread guide 3 and a convex friction shoe 4 having a special shape to which further reference will bevmade below.

A movable thread guide 5 is carried by the free end of an arm 6, the other end of which is integral with a shaft 7 of an asynchronous motor or so-called torque motor, the conventional squirrel cage rotor 8 of which is integral with the shaft 7 and rotates within the stator 9 which is supplied from any suitable alternating current source, preferably at low voltage, for example of the order of 24 volts, through supply leads which are indicated at 11, 12 in FIG. 2.

The thread 10, the tension of which is to be regulated, passes in turn through the stationary inlet thread guide 2,- againstthe: stationary convex shoe 4, through the movable thread guide. 5 and the stationary outlet thread guide 3.

The arm 6 is capable of taking up practically any of the angular positions located approximately within the half-circle, the endpositions of which are indicated at 6and at 6" in FIG. 1. The position 6" is determined by astop 15 which limits the amplitude of pivotal movement of said arm inthe direction of application of the thread against the convex friction shoe 4. When the arm takes up position 6 which is represented in full lines, the three thread guides are substantially in alignment and the thread is notin contact with the friction shoe; this is an extreme reserve position corresponding to a highly tensioned thread or else to the position assumed by the leverwhen the restoring motor is not supplied with current.

The other end position 6" corresponds to a fully slackened thread.

Finally, position 6' corresponds to an intermediate position of normal working of the apparatus.

The apparatus carries two threaded rods 21, 22 (as shown in FIG. 2) for the purpose of securing said apparatus to a suitable wall such as the wall 23, for example, by means of clamping nuts 24.

The variable-radius shoe 4 has a profile substantially in the shape ,of a semi-ellipse between two points A and B which are substantially located in diametrically opposite relation at a certain distance from the two summits of the ellipse. This shape is particularly suitable for the purpose of providing, in the first portion of travel of the arm 6 which carries the movable thread guide, a long radius of curvature of the surface of the shoe against which the thread 10 is applied, and in the second portion of travel of the arm, a radius of curvature which is considerably shorter with a resulting force of application of the thread against the shoe which is considerably greater.

In order to gain a clear understanding of the wholly characteristic advantage offered by the profile in the shape of a portion of ellipse which is given to the shoe 4, it is useful. to point out that, in conventional regulators of this type, the surface of the shoe against which the thread is caused to rub is a cylindrical surface, and this feature involves two contradictory requirements between which a compromise has to be adapted.

In point of fact:

(1) In order to ensure a wide range of regulation of the thread tension, it would be necessary to select a relatively large diameter of cylinder. It is desirable, moreover, to ensure that the range of automatic regulation comprises a position in which the thread is not in rubbing contact with the cylinder, such a position being essential if magnification of excess tension is to be prevented.

(2) It would be necessary, on the other hand, to give the friction cylinder a relatively small diameter in order that the thread can be applied to the said cylinder under negligible tension and be endowed with very frequent vibrations as the bobbins are being wound off. In this case, it must be made possible to ensure sufiicient pressure per square millimeter of surface area of thread in contact with the shoe in order to prevent the creation of a critical some of low pressure in which the friction is unstable, whatever the material employed for the fabrication of the cylinder and whatever may be the state of surface of this latter and coefficient of friction thereof.

In this connection, it should be pointed out that in such regulators comprising a friction cylinder it is impossible, by virtue of their very principle of operation, to maintain a position without friction and at the same time adopt an arrangement whereby the angle of pull of the thread can be varied without modifying the length of the arc of contact between the thread and the shoe.

As a consequence, the displacement of the feeler arm, that is to say of the movable thread guide, cannot produce action directly on the unitary pressure of contact of the thread inasmuch as the displacement of said feeler arm so acts as to increase or reduce both terms of the ratio P/S wherein P is the total effort of the thread against the convex surface and S is the area of the thread which is in contact with said surface.

However, the designs of the prior art do appear to demonstrate that the best results have been obtained when it has proved feasible, within the limits of the possibilities offered by friction shoes of cylindrical shape, to cause the feeler to produce action on the pressure applied by the thread against the convex surface of the shoe rather than on the lengthof the arc of contact.

The shoe in accordance with the invention which has the shape of a portion of ellipse offers a wide range of possibilities, and readily provides a radii of curvature in a ratio of '1 to 8.35, for example, which prove entirely satisfactory. By means of this-design, the advantages of cylin-v ders having a large diameter can be turned to profitable. account while at the same time retaining the advantages of cylinders having a small diameter.

It follows from the foregoing in particular that the following advantages can be obtained in combination:

Position of zero friction in the case of excess tension, this being the position shown in full lines in FIG. 1 in which can be seen the thread 10 passing through the three aligned

thread guides

2, 5 and 3 without rubbing against the shoe 4.

Very wide range of adjustment of the thread tension.

Direct action on the value of the unitary pressure of the thread against the shoe in the second portion of the angular travel of the movable thread guide 5 and in the Zone of small radius of the shoe by. varying the angle of pull, that is to say the angle made with the surface of the shoe at its point of contact with this latter by the portion of thread comprised between the thread guide 5 and said shoe; this pres-sure is thus varied without substantial variation in the total surface area of thread which engages the shoe in View of the fact that said surface area already corresponds to the entire long-radius portion of the shoe starting from the point A, and that the length of the short-radius portion of the shoe which is covered by the thread varies to a very small extent during these pivotal movements of the feeler arm.

Very short lever-arm of the feeler 6, although the radius of curvature of the large convex surface of the shoe is two to five times greater than in the majority of conventional regulators.

Low inertia as a result of the small length of the arm 6 which carries the movable thread guide, thus also reducing the power to be supplied thereto.

Angular travel greater than 180 without requiring any effort-multiplication system, thereby ensuring a progressive tension-regulating action and a range of automatic compensation, the flexibility of which makes it possible, without any need for manual re-adjustment of the regulator, to work textile threads of very different kinds or diameters.

Straight path of travel of the thread, which passes without friction against the shoe and against the thread guides when the feeler arm is not actuated by the torque motor, thus providing an advantage which has long been sought by users.

Substantial reserve of thread which can be released in the event of excess tension. In fact, when the feeler arm 6 passes from the position shown in full lines in FIG. 1 to the intermediate position 5' which is shown in chaindotted lines, then to the opposite end-position 5" which is also shown in chain-dotted lines, a substantial reserve of thread is thus formed.

Small overall size and very great simplicity of the apparatus as a whole.

The combined assembly is so designed and arranged that, depending on the exact form of the path which is followed by the movable thread guide 5 and which is a curve having the shape of a circular arc, on the configuration of the convex shoe which, in this example, is a curve having the shape of a portion of ellipse, on the relative position of these two curves, and on the va ue of the constant torque supplied by the torque motor, the resultant of the tension of the run of thread which arrives at the movable thread guide 5 and of the tension of the run of thread which passes out of this latter produces, by pulling on the arm 6, a torque which is equal to the resilient torque supplied by the restoring-torque motor, this being the case irrespective of the angular position of said arm.

The operation of the apparatus is therefore as follows: in steady-state operation, the thread rubs on the shoe 4 (FIG. 1). If the tension of the thread 10 on the input side of the regulator has a tendency, for example, to slacken off, the torque exerted by the thread becomes lower than the restoring torque of the motor by reason of the friction force which is applied against the shoe, with the result that the arm 6 performs a pivotal movement in the direction of the arrow f1. Consequently, the length of the arc of the shoe 4 with which the thread is in rubbing contact increases until such time as the torque exerted on the arm 6 by the increasing tension of the thread once again balances the value of the torque supplied by the restoring-torque motor. The apparatus accordingly becomes stabilized in this new position.

Conversely, if the tension of the thread 10 on the input side of the regulating apparatus were to increase, the action produced by the thread tension on the arm 6 would become preponderant over that of the restoringtorque motor, with the result that the arm 6 would accordingly perform a pivotal movement in the direcion opposite to that of the arrow f1, thereby resulting m a reduction in the friction force applied by the thread against the shoe and consequently a reduction in the torque exerted on said arm 6 by the thread. Said arm would thus pivot and consequently reduce the length of the arc of rubbing friction of the thread against the shoe until the torque which results from the tension of the thread has been reduced to a value equal to the value of the reference torque of the restoring-torque motor. The

apparatus will again be stabilized in this new position until such time as there takes place a further variation in the tension of the thread on the input side of the regulator.

The arm 6 is as light in weight as possible and, in addition, the pivotal assembly is statically balanced about the geometrical axis thereof. To this end, for example, the arm 6 is fixed on the shaft 7 of the motor through the intermediary of a member which is provided with a boss 13 on that side which is located opposite to the lever-arm relatively to the pivotal axis.

In order to set the thread tension at any desired value, it is merely necessary to regulate the torque of the restoring-torque motor to the corresponding value. This adjustment can accordingly be made from a distance by giving a corresponding value to the excitation current of the motor. Consequently, the thread tension can be remote-controlled simultaneously in all the regulating devices at the same time and can be regulated and modified at will, for example as a function of the thread feed during a thread winding operation.

In FIGS. 3 to 5, an alternative form has been shown wherein the restoring torque of the feeler arm 6 is carried out by means of a pneumatic device comprising a vane 31 mounted within a casing 32 having the shape of a circular arc and pivoted on a shaft 7a which is integral with the feeler arm 6. The casing 32 carries the stationary inlet thread guide 2 and the stationary outlet thread guide 3 as well as the convex elliptical shoe 4 which has the same configuration as that of the form of embodiment of FIGS. 1 and 2.

The vane 31 divides the interior of the casing 2 into two chambers 32a, 32b fitted respectively with a pipe 34 which is connected to a suitable source of gas under pressure and a pipe 35 which opens directly int-o the atmosphere.

The torque which must be applied to the feeler arm 6 is supplied by the difference in the pressures which prevail within the two chambers 32a and 32b of the casing and which are exerted on the two opposite faces of the pivoting vane 31. The flow of air is determined by the small leakage which occurs between the chamber 32a and the chamber 32b, along the baflles provided on the external edge of the vane 37 and on an arcuate portion 38 which forms part of the casing and which is located against the cylindrical hub of said vane.

The supply of gas under pressure, which is preferably compressed air, is effected by any suitable means of conventional type such as that which has been represented diagrammatically in FIG. 5 and which comprises an electric motor 41, an air compressor 42 which is driven from said motor, an air reservoir 43 connected to the outlet nozzle of the compressor 42, and a pressure-reducing valve 44 which is connected to the outlet orifice 45 of the compressed air reservoir 43 and which determines the pressure of compressed air delivered to a general supply pipe 46 which is connected to the nozzle 34 through a branch pipe 47 whilst other branch pipes such as 47a, 4712, etc., serve to feed other regulators of similar design. A pressure gauge 48 indicates the pressure in the general supply pipe 46.

The operation of said regulator is the same as that described in reference to the form of embodiment of FIGS. 1 and 2, the only difference being that the restoring torque to which the feeler arm 6 is subjected is supplied by the pneumatic system described above instead of being supplied by a torque motor.

The compressed air at low pressure which is intended to supply the pneumatic device calls for a lower consumption of power than that which is required by an electric torque motor while at the same time supplying a maximum torque of substantially the same value and a responsiveness which is comparable to that of the form of embodiment in which the restoring torque is supplied by a torque motor.

In FIGS. 6 and 7,.there is shown an alternative form of embodiment wherein the pneumatic means for restoring or returning the movable thread guide no longer comprise a pivoting vane but comprise instead a circular flexible diaphragm 51, the edge of which is clamped over the. periphery of a capsule 52 provided with a pipeconnection 53 for the purpose of connecting said capsule to a source of fluid under constant pressure. The central portion of the flexible diaphragm 51 is strengthened by two

discs

54, 55 which are secured respectively against the two faces of said central portion of the diaphragm, for example by means of a rivet 56.

The manometric capsule 52 is fixed flat in the bottom of a box 57 on which are supported, as in the form of embodiment of FIGS. 3 to 5, the stationary inlet thread guide 2'and stationary outlet thread guide 3 as well as the movable thread guide 5 which is integral with an arm 6a which is mounted on a pivot-pin 7b, said pivot-pin.

being journalled in two bearings 61, 62secured to a support 63 which is integral with the box 57. Said box additionally carries the. convex elliptical shoe 4;

The kinematic connection between the pivot-pin 7b of the movable thread guide Sand the diaphragm 51 of the manometric capsule consists of a bevel pinion 65 which is integral with the pivot-pin 7b and engaged with a corresponding toothed sector 66 which is made fast with a shaft 67, the two ends of which are pivotally mounted in two lugs 68, 69 forming part of'the casing 57, the direction of the shaft 67 being at'right angles to that of the shaft of the pivot-pin 7b which supports the movable thread guide. The toothed sector 66 forms one piece with an arm.71, the extremity of which is. adapted to bear against the rivet 56 which is secured to the cena tral portion of the diaphragm.

The outer face of the diaphragm 51 is accordingly subjected to atmospheric pressure whilst the inner face thereof'is subjected to the pressure of the source of fluid under constant pressure with the result that this latter exerts the desired restoring torque on the movable thread guide 5 through the intermediary of the drive system described above.

The operation of the regulator which has just been described is the same as that of the form of embodiment of FIGS. 3 to 5, the only difference being that the restoring torque of the movable thread guide 5 is supplied by different pneumatic means.

It will be understood that the invention is not limited to the forms of embodiment which have been described and illustrated andthat a large number of modifications can be made therein without consequently departing either from the scope or the spirit of the invention.

It accordingly follows, for example, that in the form of embodiment described, the stationary inlet and outlet thread guides form part of the regulating apparatus but can equally well be incorporated in the textile machine on which said apparatus is mounted.

What I claim is:

1. A thread tension regulating device comprising: a casing, a stationary inlet thread guide secured to said casing, a convex shoe secured to said casing and having a long radius portion adjacent said inlet thread guide and a shorter radius portion remote from said thread guide, a movable thread guide pivotally mounted on said casing, a stationary outlet thread guide secured to said casing, said movable guide being operatively associated and located with respect to said convex shoe so that thread threaded successively through said inlet guide, said movable guide and said outlet guide will frictionally engage an arcuate portion of said convex shoe which is longer and longer as said movable thread guide is pivoted more and more in a predetermined direction, and means mounted in said casing for resiliently urging said movable thread guide in said predetermined direction with a constant torque adapted to always balance the torque exerted by the thread tension upon said movable thread guide.

2. A device accordingto claim 1, wherein said convex shoe is substantially in the shape of half an ellipse between two points thereof substantially diametrically opposed and located at a predetermined distance from the end of the major axis of said ellipse.

3. A device according to claim 1, wherein said means for resiliently urging said movable thread guide is an electric torque motor.

4. A device according to claim 1, wherein said means for resiliently urging said movable thread guide are pneumatic means.

5. A device according to claim 4, including a partition which is movable in said casing, said partition sealingly dividing said casing into two chambers, one of said chambers being in permanent communication with the atmosphere while the other is adapted to be connected to a suitable constant pressure fluid source.

6. A device according to claim 5, wherein said partition is constituted by a vane pivotally mounted in said casing, said casing being at least partially cylindrical.

References Cited by the Examiner UNITED STATES PATENTS 1,475,855 11/1923 Murdock. 2,331,261 10/ 1943 Wholton 242-154 FOREIGN PATENTS 523,580 7/1940 Great Britain. 833,425 4/1960 Great Britain. 1,334,485 7/ 1963 France.

JORDAN FRANKLIN, Primary Examiner.

Claims

1. A THREAD TENSION REGULATING DEVICE COMPRISING: A CASING, A STATIONARY INLET THREAD GUIDE SECURED TO SAID CASING, A CONVEX SHOE SECURED TO SAID CASING AND HAVING A LONG RADIUS PORTION ADJACENT SAID INLET THREAD GUIDE AND A SHORTER RADIUS PORTION REMOTE FROM SAID THREAD GUIDE, A MOVABLE THREAD GUIDE PIVOTALLY MOUNTED ON SAID CASING, A STATIONARY OUTLET THREAD GUIDE SECURED TO SAID CASING, SAID MOVABLE GUIDE BEING OPERATIVELY ASSOCIATED AND LOCATED WITH RESPECT TO SAID CONVEX SHOE SO THAT THREAD THREADED SUCCESSIVELY THROUGH SAID INLET GUIDE, SAID MOVABLE GUIDE AND SAID OUTLET GUIDE WILL FRICTIONALLY ENGAGE AN ARCUATE PORTION OF SAID CONVEX SHOE WHICH IS LONGER AND LONGER AS SAID MOVABLE THREAD GUIDE IS PIVOTED MORE AND MORE IN A PREDETERMINED DIRECTION, AND MEANS MOUNT-