US3231216A

US3231216A - Thread tensioning device for textile machines

Info

Publication number: US3231216A
Application number: US251554A
Authority: US
Inventors: Lemarchand Francis
Original assignee: Machines Bourgeas Pain SA
Current assignee: Machines Bourgeas Pain SA
Priority date: 1962-01-19
Filing date: 1963-01-15
Publication date: 1966-01-25
Anticipated expiration: 1983-01-25
Also published as: FR1319433A; ES284325A1

Description

Jan. 25, 19:66 F. LEMARCHANDQ 3,231,216

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' ATTORNEY United States Patent 3,231,216 THREAD TENSIONING DEVICE FOR TEXTILE MACHINES Francis :LemarchamL Rouen, France, asslgnor to Machines Bourgeas Pain, Valence, Drome, France, a French company Filed Jan. 15, 1963, Ser. No. 251,554 Claims priority, application France, Jan. l19, 1962, 885,294, Patent 1,319,433 9 Claims. (CI. 242-150) Theinvention relates to thread-tensioning devices for textile machines such as, for example, creeis,V reelingmachines, spoolers, winders, false-twist machines, etc.

In the majority of known thread-tensioning devices, the thread passes over two tension cylinders which are positionally adjustable at the outset but which remain stationary during the operation of the machine, the thread being guided, at least on the output side of the said tension cylinders, by means of a roller or like guiding member which is subjected tothe actionof an adjustable counterweight.

In the case of devices of this type, it is difficult to adjust the tension of the'thread during operation of the machine and it is in any case necessary to carry out this adjustment individually by hand on each thread-tensioning device, with the result that, in order to adjust all the thread-tensioning devices of a same machine, a relatively substantial amount of time has to be spent.

The purpose of the invention is to construct a threadtensioning device which not only ensures that the thread tension is automatically regulated to a constant predetermined value, but also makes it possible to modify the value of this tension at any desired moment during the operation of the machine, either by manual control means or by automatic means, as a function of time or of a pre-determined programme, for example in response to the diameter of the bobbins of threadwhich are undergoing formation on the machine, and finally, which makes it possible to eifect a simultaneous adjustment of all the tensioning devices of a same machine, star-ting from a single common adjustment unit.

To this end, in accordance with the invention, the thread tension regulating device comprises a feeler element with a-roller which is elastcally urged against the thread with a constant pressure which can preferably be regulated, and a thread tension regulating system controlled by the said feeler element in such manner that, depending on whether the thread tension tends to increaseV or decrease, the feeler roller is thrust back either in one direction by the thread or in the opposite direction by the elastic means actuating the said feeler element and produces action on the thread tension regulating system in the direction of a reduction or increase respectively, so as to compensate incipient variations in tension.

By virtue of this constructional arrangement, and in view of the fact that the feeler element acts upon the thread tension regulating system so as to compensate possible variations in tension, it will be understood that a very flexible and very effective regulation of tension is thus obtained and that it is possible to effect a modification of the value of the thread tension simply by varying the pressure applied by the feeler element on the thread.

The invention also has for its object forms of embodiment which comprise at least one of the following characteristic features:

(a) The thread tension regulating system is constituted by two parallel tension cylinders around which the thread passes in an S, the said cylinders being carried by a support which pivots about a shaft mounted parallel to to the feeler element.

the axes of the tension cylinders and which is coupled hmtif l Patented Jan.,` Z5, w66

(b) The thread tension regulating elements are conn stituted by two discs between which the threads pass, the said discs being urged towards each other by the feeler V t (d) Ther tension cylinders are carried by aA supportl which is adapted to pivot co-axially with the arm which carries the two feeler rollers, in the direction opposite Ato the said arm and preferably in a speed ratio which is greater `than unity, especially'of the order of 2:1.

(e) The coupling between the arm which carries the feeler rollers and the support which carries the tension cylinder is constituted by two toothed wheels which are respectively integral with the said arm and with the said support, the said two toothed wheels being in mesh with a common intermediate toothed wheel, the shaft of which is stationary.

(f) The arm which carries the feeler rollers and the support which carries 'the tension cylinders are connected together by means of a coupling comprising two crankpins which are respectively integral with the coaxial shafts of the said arm and the said support and which l" are coupled at two points of an intermediate pivotal lever which are located at distances from the fulcrum of this y latter which are respeetively'proportionali to the angular speeds of the arm and of the support. 4

(g) The two discs of the disc-type tensioning device are respectively coupled axially to two coaxial shafts which are movable one with respect to the other, both axially and in rotation, one of the said two shafts being designed to carry the pivotal arm which supports the feeler roller whilst the other shaft is secured against rotation and a cam transmission produces the relative sliding of the two shafts under the action of the pivotal motion of that shaft which carries the feeler roller.

(h) The feeler roller is urged against the thread by means of an electromagnetic device such as, for example, an electric motor of the type known as a torque-motor.

(i) The electromagnetic device comprises a' pivoting system which is secured to the arm tted with the feeler roller and which carries two pole'pieces adapted to move in front of two stationary pole pieces which are displaced angularly in such manner that, when the area of the airgap between two oppositely facing pole pieces decreases, the area of the air-gap between the two other oppositely facing pole pieces increases, two of the opposite faces having the same polarity whilst the two other opposite faces have different polarities in order that the torque` provided by the moving system may be substantiallyv constant, irrespective of the angular position thereof.

(j) The circuit supplying current to the electromagneticV device which applies the feeler roller against the thread is placed under the control of a device such as a r eostat which comprises a moving element coupled to a member, the displacements of which are dependent on the value of the diameter of the bobbin of thread which is undergoing FIG. .3 is a partial transverse cross-section taken along the line III-III of FIG. l,

FIG. 4 is a transverse cross-section taken along the line IV-IV of FIG. l,

FIG. S'is a plan view which is similar to FIG, 2 and which shows the members in another position,

FIG. 6 is an axial cross-section of a first variant of the form of embodiment of FIGS. 1 to 5,

FIG. 7 is an axial cross-section taken along the line VlI-VII of FIG. 6,

FIG. 8 is an axial cross-section of a second variant,

FIG. 9 is a partial transverse cross-section taken along the line IX-IX of FIG. 8,

FIG. 10 is a view which is similar to FIG. 9, and which shows the members in another position,

FIG. 1l is an axial cross-section of another form of embodiment taken along the line XI-XI of FIG. 15,

FIG. 12 shows on a larger scale a detail of FIG. 11,

FIGS. 13 and 14 are cross-sections taken respectively along the lines XIII- XIII and XIV-XIV of FIG. 12,

FIG. 15 is al plan view which corresponds to FIG. 11,

FIG. 16 is a view which is similar to FIG. l5 and which shows the members in another position, and

FIG. 17 is an electric circuit diagram of an installation for the control of a series of tensioning devices in accordance with the invention which arel mounted on a textile machine.

The thread-tensioning device which is illustrated in FIG. 1 comprises a box 1 inside which are mounted two vertical co-axial shafts, namely: an internal shaft 2 and an external tubular shaft 3 which support respectively at the top extremities of the said shafts a bracket 4 which carries'two

tension cylinders

5, 6 and an arm 7 which carries two rollers, namely, a feeler roller 8 and guide roller 9 (see also FIG. 2).

The two tension cylinders and 6 have their axes parallel to the shaft 2 and are rigidly yfixed to the bracket 4, that is to say, the said tension cylinders do not rotate about their own axes. The two

rollers

8 and 9 are grooved rollers which are, on the contrary, mounted for rotation on

shafts

11 and 12 which are respectively fixed on the two extremities of the arm 7. The said arm is fixed on the tubular shaft 3 by means of a clamping screw 14 which -passes through a hub 15, the said hub being integral with the said arm.

The thread 20, the tension of which it is desired to adjust, passes in the direction of the arrow f1, first over the input guide roller 8, then over the two

tension cylinders

5 and 6 so as to form an S and lastly over the output guide roller 9.

The pivotal arm A7 which carries the feeler rollers and the bracket 4 which carries the tension cylinders are coupled for rotation by means of a step-up system which comprises an internally toothed ring gear 22 and an externally toothed wheel 23 which are respectively secured to the tubular shaft 3 which carries the rollers and to the internal shaft 2 which carries the tension cylinders, whilst the internally-toothed ring gear 22 and the externally toothed wheel 23 are both in mesh with an intermediate toothed wheel 24 which is mounted to rotate freely on a pin 25 which is rigidly secured in the bottom of the box 1. The pitch diameter of the ring gear 22 is, in this example, substantially double the diameter of the toothed wheel 23, with the result that the angular displacement of the bracket which carries the tension cylinders is approximately double the angular displacement of the pivotal arm which carries the feeler rollers, and takes place in the opposite direction.

The pivotal arm 7 which carries the feeler rollers is induced to perform a pivotal movement in the direction of the arrow f2 (as shown in FIG. 2) and, in consequence, the bracket which supports the tension cylinders is induced to rotate in the opposite direction with an amplitude and an agular speed which are double, under the action of a device which, in this example,is of the electromagnetic type comprising a rotor which is generally designated by the reference 28, and a stator which is generally designated by the reference 29.

The -rotor 28 which is mounted on the tubular shaft 3 comprises two

pole pieces

31, 32 which are intended to co-operate respectively with two

pole pieces

33, 34 of the stator. In order that the total reluctance of the airgap between the stator and the rotor should rem-ain substantially constant, there has -been given to the two pole pieces of the stator a suitable angular displacement which is different from that of the pole pieces of the rotor.l In this manner, when one of the two air-gaps decreases in area, the other air-gap increases, thereby making it possible to retain a substantially constant torque, 'while steps are taken to ensure that the two oppositely facing pole pieces, for example the pole piece 31 of the rotor and the pole piece 33 of the stator both have like poles, for example north-seeking or positive poles, whereas the two opposite faces of the two

other pole pieces

32 and 34 have unlike poles, in order to ensure that two pole pieces repel each other while the other two -pole pieces attract each other and that their combined action should consequently be in the same direction, that is to say, in the example, the direction of the arrow f2.

There has been diagrammatically illustrated in FIG. 1 the electric circuit for the excitation of the pole pieces of the rotor and of the stator. The electric current flows into the box 1 through a supply lead 41 and passes successively through the coil 42 of the pole piece 33 of the stator, through a brush 43 which is secured to the box cover l0 by means of an insulating member 44, through the brush-contact 43 to a collecting-ring 45 which is mounted on an insulating tube 46 fixed on the tubular shaft 3, through a supply lead 47, through the coil 48 of the pole piece 31 of the rotor, the coil 49 of the pole piece 32 of the rotor, through another collecting-ring 51, a brush 52, and through the coil 53 of the pole piece 34 of the stator, whereupon the current finally passes out of the box through a lead 54.

The operation of the device takes place as follows:

It is assumed that the apparatus is at present in stable condition of operation. Accordingly, the thread 20 has a tension which balances the pressure with which the feeler and guide

rollers

8 and 9 as well as the

tension cylinders

5 and 6 are applied against the thread under the action of the constant torque provided by the electromagnetic device.

If for any reason the tension of the thread shows a tendency to decrease, for example, the lpivotal arm 7 which carriesthe feeler rollers will pivot in the direction of the arrow f2 under the action of the predominant torque of the electromagnetic device, with the result that the

tension cylinders

5 and 6 will pivot together in the direction opposite to the arrow f2 and that consequently, the arc over which the thread is wound onto the' said tension cylinder-s will increase; this results in an increase in the tension'of the thread, which tends to cause the

feeler rollers

8 and 9 to move back to the same extent as they had moved forward under the 4action of the pre dominant driving torque of the electromagnetic device.

In the contrary case, that is to say if the tension of the thread tended to increase, the feeler rollers would be thrust back in the direction opposite to the arrow f2, with the result that the tension cylinders would perform a pivotal movement in the direction of the said arrow while producing a decrease in the length of the are over which the thread rubs against the said cylinders, which would have the effect of reducing the tension of the thread and of initiating the return of the pivotal systems to their po sition of stable operation.

In FIG. 2, there have been illustrated the moving systems in a mean position in which it is effective and, in FIG. 5, in a position which corresponds to the maximum tension of the thread in which the device is not effective until the tension produced by the delivering and receiving l machines is reduced.

The multiplication of the amplitude of the movement and of the speed of the feel-er rollers with respect to the tension cylinders provides the apparatus with great sensitivity, a small response time and rapid compensation of variations' in tension for small angular displacements of the feeler rollers, thereby preventing troublesome timeylags and considerably increasing the range of adjustment provided by the apparatus.

In order to regulate the thread tension to the desired Value, it is merely necessary to regulate the current intensity in the electromagnetic device to the value which corresponds to the torque which is necessary for the pur- -pose of applying the feeler rollers against the thread with the corresponding pressure.

The form of embodiment which is illustrated in FIGS. 6 and 7 resembles the form of embodiment of FIGS. l to 5 and the same members have been designated by the same reference numerals; it essentially differs only in the fact that the stepup gear device, instead of being con stituted by straight-tooth gears, is constituted by beve1- gears.

The arm 7 which carries the feeler rollers is mare integral with a bevel-gear 61 which is secured to shaft 2 and in mesh with an intermediate bevcl-gar 62 which is mounted to rotate freely on a shaft 63, the said shaft being carried by a support 64 which is mounted on the `cover of the box, the said bevel-gear 62 being in t-urn engaged'at the same time with a bevel pinion 66, the pitch diameter of which is substantially one half the pitch diameter of the bevel-gear 61. In this form of embodiment, the bevel pinion 66 is provided with a collar 67 in which are directly mounted the two

tension cylinders

5, 6. The said pinion and its collar rotate freely on the shaft 2 which in this case, is directly coupled to the rotor 28 and is journalled in the box casing and box cover, the tubular shaft of the previous form of embodiment being no longer provided in this alternative form.

A casing 68 protects the reduction gear unit.

The said device obviously operates in the same manner as the device which is described with reference to FIGS. 1 to 5.

The form of embodiment which is illustrated in FIGS. 8 to l() also differs from the form of embodiment of FIGS. 1 to 5 solely in the structure of the step-up gear device which, instead of being in the form of gears, is designed in the form of levers which are pivotally coupled to each other.

' The internal shaft 2 which carries the tension cylinders at the top extremity thereof is rigidly fixed at the bottom extremity thereof to a crank-pin 71 whilst the bottom extremity of the tubular shaft 3 which carries the feeler rollers is tted with a crank-pin 72 having substantially the same length as that of the crank-pin 71, the two crank-pins being substantially diametrically opposite in the central position of adjustment of the device. The stud 73 of the crank-pin 71 is engaged inside an elongated slot 74 which is formed in the free extremity of a lever 75 (see also FIGS. 9 and l0) which pivots at the other extremity thereof about a pin 76 which is made integral with the bottom of the box 1. The stud 78 of the crankypin 72 is housed in a similar manner inside as elongated slot 79 which is formed in the lever 75 at a distance from the pin 76 which is substantially equal to one half the distance between the elongated slot 74 and the said pin.

Accordingly, any angular displacement of the intermediate lever 75 corresponds to an angular displacement of the crank-pin 71 which is substantially equal to double the angular displacement of the crank-pin 72. The same effort-multiplication ratio is thus found between the pivotal arm which carries the feeler rollers and the bracket which carries the tension cylinders as in the forms of lembodiment which have been described in the foregoing. For constructional reasons, provision has stead of being designed in the form of two tension cyl` inders, is designed in the form of two` discs 91, 92 which are applied elastically one against the other with a pres- ,sure whichcan be regulated.

Further reference will not be made to the method of assembly of the feeler rollers or to the manner in which these latter 4are urged against the thread as a result of the torque which is produced by the electromagnetic system. The bottom thread-tensioning disc 91 is tted freely on .an internal shaft 93 which is mounted inside the tubu- A lar shaft 3 which carries the feeler rollers. i A locking-pin i 94 passes through the bottom extremity of the internal shaft 93, the extremities of the said locking-pin being Y.

adapted to slide in two

longitudinal slots

95, 96 formed in a socket 97 provided with a cylindrical extendedl por tion 98 which is force-fitted in a hole 99 formed in the base of the box 1. The internal shaft 93 can therefore slide vertically but cannot rotate about :its own axis.

The top extremity of the shaft 93 is threaded and is fitted with a knurled regulating knob 101 by means of which it is possible to compress to a greater or lesser extent a spring 102, one end of which is'applied against the bottom end of the said knob whilst the other end of the spring is applied against a washer 103 which bears onA the upper face of the top disc 92 provided for the purpose of regulating the thread tension.

The end annular face of the bottom extremity of the tubular shaft 3 is cut in the shape of a cam 105 in such `manner that, when the said shaft is caused to perform The thread 20, the tension of which it is desired toI regulate, is guided between the two feeler rollers andy tightly` held between the two discs 91, 92.

The operation of this device is similar to` that of those forms of embodiment which have been described above and differs therefrom solely in the fact that the increase in tension of the thread, instead of taking place under' the effect of an increase in the length of thearc over which the thread is wound onto the tension cylinders,

is obtained as a result of an increase in the pressure applied by the two discs 91, 92 under the action of the downward movement of the shaft 93 which produces a slightlyl greater compression of the spring 102 which applies the top disc against the bottom disc.

The said downward movement of the shaft corresponds to a pivotal movement of the system of feeler rollersin the direction of the arrow f2 (as shown in FIG. 15), which in turn corresponds to a tendency towards initial reduction in thread tension. thread tension will accordingly be compensated by a corresponding increase which is in turn due to the im crease in the clamping pressure of the two discs.

As the knurled knob 101 is screwed down further on the top .portion of the apparatus, so the pressure of the spring is increased and the tension of the thread is consequently also increased und'er stable operating conditions.

FIG. 16 shows the, relative position of the members i in the case of a substantially maximum tension setting.

The devices such as have been described above in var- The said reduction in ions forms are very well suited to the adjustment, as effected both simultaneously and from a distance, of the tension of the threads in all the sections of a textile machine suoli as, for example, a multiple-spindle machine, either as a function of time 'or in compliance with any desired law. It accordingly follows, for example, that in FIG. 17, there have been shown a certain number ot devices 111vfor regulating-the thread tension which are titte'd with a control electromagnetic system of the same type as that which has been described above, for example, all such systems being fed in parallel from an electric circuit comprising the following essential elements: a power line 112 supplying alternating current, a general switch 113, fuse units 114, a transformer 115, a rectifier 116, an initial-setting rheostat 117 and a rheostat 118 for the automatic adjustment of the thread tension in response to a system 121 which is connected to a unit 122, the displacements of which are dependent on the diameter of cach bobbin of thread which is undergoing formation. ln this manner, the adjustment of thread tension is effected simultaneously on all the spindles as aA function of the diameter of the bobbin which is undergoing formation.

It accordingly follows, for example, that, although two feeler rollers have been illustrated in the drawings, especially for reasons of symmetry and primarily of balancing, it would be suflicient to provide one roller only at the output end.

It will be understood that the rheostat 118 can be replaced by any other device by means of which the terminal voltage can be varied, the said device being inserted, for example, in the alternating current circuit before the rectifier 1,16, and consisting of a transformer or multiple-tapping autotransformer, variable-core inductance and, generally speaking, any means which makes it possible to produce action on the current intensity simul Y taneously in all the apparatuses which are in service on one machine or on a part of one machine.

By way of example, the following numerical data can be given in the case of an apparatus which is constructed for a winding machine:

min.

dev-ice (this latter being located in lthe mean opening position): 8/ 100 sec.

Diameter of the tension cylinders: 9 mm.

Angle of total displacement of the feeler rollers: 45.

Angle of total displacement of the tension cylinders: 90.

Supplemental length of thread gripped between arms in the closed position of the tension cylinders as comparyed with the open position of the tension cylinders: 40 o.

Thread employed for test purposes: Cotton, Nm 28/2,

twisted to 500 turns per metre.

When the tensioning device comprises a control system consisting of an input feeler member and an output feeler member, it is advantageous in the case of certain applications which can concern, for example, the use of reeling machines, winding machines, spoolers, etc., to make the elastic means which act upon the tensioning device dependent not upon a constant torque but on a decreasing torque. In other words, if the tension of the Vwhich can be common to all thread on the input feeler member were to decrease,

member and thus producinga'preponderance of the saidactuating means, the resulting effect of which is an angular displacement of the control system, the driving torque applied on the control system would tinally decrease as a function of the said angular displacement.

There has been given in the foregoing description an explanation of the manner in which the said displacement produces action on the tension-regulating system so that the tension of the thread at the output end does not undergo any decrease in spite of the reduction in tension at the input end.

This variation yin the value of. the driving torque of the apparatus as a function of the amplitude of angular displacement of the tensioning device is determined in such manner that, in any position of the control system, the driving torque balances the sum of tensions both at the input and output end, whilst the output tension is mainu tained substantially constant.

Depending on the nature of the variations in the tension to be controlled and compensated, namely, frequency, amplitude, speed of the thread considered, or depending also on the characteristics of the threads employed, namely, the nature, size, elasticity, fragility, twist, etc., or finally according to whether the thread, the tension of which it is desired to control, is delivered freely or by means of adelivery roll, or through a false-twist spindle or at the output of a device fitted with tins or rings or of a single-twist or double-twist spindle, etc., the etectiveness of compensation and the stability of the tension of the thread at the output end of the apparatus are obtained either by making use of a constant driving torque or a decreasing driving torque.

Furthermore, it can be found that, on a same machine, an optimum tension-setting of the threads is obtained in certain cases by means of constant-torque tensioning devices, and in other cases by means of tensioning devices in which the torque decreases in time and also decreases according to the angular displacement of the control system. The apparatus in accordance with the invention is designed to carry out all these functions at will.

Moreover, the ratio of decrease in torque as a function of the position of the tensioning device can be remotecontrolled by means of an adjustment unit or regulator the tensioning devices of a machine.

This adjustment can be either manual or automatic, and can, for example correspond to a pre-arranged programme in which the return to constant torque at any given moment can be both directed and obtained.

This range of possibilities is given to the apparatus by the operation of a variable shunt which branches the internal electric circuit of the constant-torque electromagnetic control in such manner that the current intensity can decrease in "those coils in` whichthe pole Y pieces repel each other while the intensity increases in those coils in which the pole pieces attract each other. The said shunt is represented in broken lines in FIG. 17.

A single rheostat 123 can,.for example, carry out this function for the combined assembly of tensioning devices which are mounted on one machine.

On the tensioning device itself, a third lead terminal at 124 (as shown in FIG. 1) is alone suicient to endow the apparatus with this possibility of instantaneous modifcation of the nature of the driving torque, namely either constant torque or decreasing torque.

On the basis of the above data, it will be understood that the adjustment of the tension of the threads on either one or a number of machines can comply with any law of constancy or of variation.

The association of a number of tensioning devices of the present invention, the same applying in the case assiste controlling the feeler system.

It will naturally be understood that `the invention is not limited to those forms of embodiment which have been described and illustrated and which have been given solely by way of example, and that numerousl modifications can be made therein without consequently departing either from the scope or the spirit of the invention.

What I claim is:

1. A thread tensioning device comprising supporting means; a feeler element mounted on said supporting means for turning movement and adapted to engage a thread; a thread tensioning element movably mounted on said supporting means and adapted to engage the thread for increasing or decreasing the tension of the same; transmission means connecting said feeler element with said thread tensioning element so that said thread tensioning element and said feeler element move opposite to each other for increasing or decreasing the tension of the thread; torque creating means including a stationarily mounted member and a turnable member, said members being mechanically unconnected for torque transmission, and electromagnetic means creating between said stationary and said turnable member an electromagnetic torque the force of which is independent of the position of said turnable member, said turnable member being connected to one of said elements for urging the same against the thread at a torque which is independent of the position of said elements, whereby both said elements exert a selected torque on the thread irrespective of the relative position of said elements and of the tension of the thread.

2, A thread tensioning device comprising supporting means; a feeler element mounted on said supporting means for turning movement and adapted to engage a thread; a thread tensioning element movably mounted on said supporting means and adapted to engaged the thread for increasing or decreasing 'the tension of the same; transmission means connecting said feeler element with said thread tensioning element so that said thread tensioning element' and said feeler element move opposite to each other for increasing or decreasing the tension of the thread. said transmission means turning said thread tensioning element at a different speed than said feeler element; torque creating means including a stationarily mounted `member and a turnable member, said members being mechanically unconnected for torque transmission, and electromagnetic means creating between said stationary and said turnable member an electromagnetic torque the force of which is independent of the position of said turnable member, said turnable member being connected to one of said elements for urging the same against the thread at a torque which4 is independent of the position of said elements, whereby both said elements exert a selected torque on the thread irrespective of the relative position of said elements and of the tension of the thread.

3. A thread tensioning device comprising a casing; a feeler; a support for said feeler turnably mounted on said casing for causing engagement of a thread by said feeler; torque creating means mounted in said casing and including a stationarily mounted member and a turnable member, said members being mechanically unconnected for torque transmission, andelectromagnetic means creating between said stationary and said turnable member an electromagnetic torque the force of which is independent of the position of said turnable member, said turnable member being connected to said support for urging said feeler against the thread at a torque which is independent of the position of said elements, whereby both said elements'exert a selected torque on the thread irrespective of the relative position of said elements and of the tension of :the thread; thread tensioning means en gaging the thread and movably mounted on said casing to increase or decrease the tension of the thread; and transmission means operatively connecting said support with said thread tensioning means for increasing the tension of the thread as saidlfeeler element is moved by said torque creating means against the action of the' decreasing thread tension or is moved back by the thread when the thread tension increases to such extent as to` overcome the constant torque of said torque creating means.

' 4. A thread tensioning device comprising a casing; a feeler; a support for said feeler turnably mounted on said casing for causing engagement of a4 thread by said feeler; torque creating means mounted in said casing and including a stationarily mounted member and a tumable member, said members being mechanically unconnected for torque transmission, and electromagnetic means cre'- ating between said stationary and said turnable member an electromagnetic torque the force of which is independent-of the position of said turnable member, said turnable member being connected to said support for urging said feeler against the thread at a torque which is independent of the position of said elements, whereby both said elements exert a selected torque on the thread irrespective of the relative position of said elements and of the tension of the thread; thread tensioning means including a carrier mounted on said casing for turning movement about the turning axis of said support arm, and a pair of tension cylinders having parallel axes parallel to said turning axis, said tension cylinders engaging the thread to increase or decrease the tension of the thread; and transmission means operatively connecting said support with said thread tensioning means for increasing the tension of the thread as said feeler is moved by said torque creating means against the action of the thread tension when said thread tension decreases to such an extent as to be overcome by the constant torque of said torque creating means or to decrease the tension of the thread when the feeler is moved back by the thread when the thread tension increases to such extent as to overcome the constant torque of said torque creating. means..

5. A thread tensioning device as set forth in claim 4 wherein said support includes an arm having said4 slots spaced ditferent distances from the pivot axis of the intermediate lever and respectively receiving said pins whereby said thread tensioning means and said support` vand feeler move at different selected angular speeds.

7. A thread tensioning device comprising a casing; a feeler; a support for said feeler turnably mounted on. said casing for causingengagement of a thread by said feeler; torque creating means mounted in said casing and rincluding a stationarily mounted member and a turnable member, said members being mechanicallly unconnected f for torque transmission, and electromagnetic means creating between said stationary and said turnable member an electromagnetic torque the force of which is independent of the position of said turnable member, said turnable member being connected to said support for urging said feeler against the thread at a torque which is independent of the position of said elements, whereby both said elements exert a selected torque on the thread lmovement toward andl away from the other disc; and

transmission .means operatively connecting said support with said one disc for moving the same toward said other disc for increasing the tension ofthe thread as said feeler is moved by said torque creating means against the action of the thread tension when said thread tension decreases to such an extent as to be overcome by the constant torque of said torque creating means or to decrease the tension of the thread when the feeler is moved back by the thread when the thread tension increases to such extent as to overcome the constant torque of said torque creating means.

8. A thread tensioning device as set forth in claim 7 wherein said support includes an arm having said feeler at one end, and a tubular shaft secured to said arm and mounted in said casing for turning movement, said other disc'being secured to said tubularshaft, an inner shaft located in said tubular shaft for axial and turning movement, means mounting said inner shaft on said casing nonrotatably and axially movable; wherein said spring means is a helical spring surrounding said inner shaft and abutting said one disc; a projection on said inner shaft on which said spring abuts; and wherein said transmission means includes cooperating camming means on said tubular shaft and on said inner shaft, respectively, for moving said inner shaft and said one t 12 disc against the action of said helical spring when said tubular shaft is turned.

.9. A thread tensioning device as set forth in claim 3 wherein said torque creating means'includes a rotor having two diametrically arranged rotor pole piecesextending the same angular distance, and a stator having two stator pole pieces each of which extends the same angular distance as said pole pieces of said rotor, said stator pole pieces being angularly spaced an angle equal to less the angular extent of any one pole piece, one of said rotor pole pieces cooperating with a stator pole piece of like polarity while the other rotor pole pececooperates with a stator pole piece of opposite polarity.

References Cited by the Examiner UNITED STATES PATENTS 1,459,332 6/ 1923 Hineline 242-154 2,326,714 8/ 1943 Whalton 242-154 2,554,493 5/1951 Heizer 242-150 2,685,417 8/ 1954 Bartelson 242-154 X 2,833,491 5/ 1958 Carroll 242-154 FOREIGN PATENTS 915,401 7 1946 France.

22,908 1 1/ 1900 Switzerland.

MERVIN STE-IN, Primary Examiner. RUSSELL C. MADER,-Exwniner.

S. N. GlLREATH, Assistant Examiner.

Claims

1. A THREAD TENSIONING DEVICE COMPRISING SUPPORTING MEANS; A FEELER ELEMENT MOUNTED ON SAID SUPPORTING MEANS FOR TURNING MOVEMENT AND ADAPTED TO ENGAGE A THREAD; A THREAD TENSIONING ELEMENT MOVABLY MOUNTED ON SAID SUPPORTING MEANS AND ADAPTED TO ENGAGE THE THREAD FOR INCREASING OR DECREASING THE TENSION OF THE SAME; TRANSMISSION MEANS CONNECTING SAID FEELER ELEMENT WITH SAID THREAD TENSIONING ELEMENT SO THAT SAID THREAD TENSIONING ELEMENT AND SAID FEELER ELEMENT MOVE OPPOSITE TO EACH OTHER FOR INCREASING OR DECREASING THE TENSION OF THE THREAD; TORQUE CREATING MEANS INCLUDING A STATIONARILY MOUNTED MEMBER AND A TURNABLE MEMBER, SAID MEMBERS BEING MECHANICALLY UNCONNECTED FOR TORQUE TRANSMISSION, AND ELECTROMAGNETIC MEANS CREATING BETWWEN SAID STATIONAY AND SAID TURNABLE MEMBER AND ELECTROMAGNETIC