US 3924818 A
Abstract available in
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Description (OCR text may contain errors)
I United States Patent [1 1 i 1 3,924,818
Pfeifle Dec. 9 1975 THREAD STORAGE DEVICE 3,720,384 3/1973 Rosen 242/47.01 [751 Invent Dieter Pfeifle, Plattenhardt, $332332 551332 33223111111111:1111:1331: 52552312; Germany 3,822,833 7/1974 Fecker 242/47.12  Assignee: SKF Kugellagerfabriken Gmbl-I,
S h i f t Germany Primary Examiner-Stanley N. Gllreath  Filed: Feb. 19, 1974  ABSTRACT PP 443,832 The disclosure relates to apparatus and method for ac cumulating and feeding thread from a supply to a pro-  Foreign Application Priority Data cessing station, over a rotating cylindrical storage Feb 20 1973 German 2308203 member. The thread 1s initially passed from the supply 0 l l 973 G y 2350979 to the peripheral surface of the storage member on the c ermany peripheral edge of a conjointly rotating disc having an axis oblique to that of the storage member. The disc is i g arranged with respect to the storage member so that  Field 47 0l 47 its lateral face engages the passing thread urging it to wind on the peripheral surface of the storage member into a coil and thereafter urging the coil to move axi-  References Cited ally on the peripheral surface of the storage member. The storage member is a drum having longitudinal UNITED STATES PATENTS slots and the disc has radial teeth extending through 2,387,252 10/1945 Furness 242/47.05 the slots, so that they are conjointly rotatable. Means 1 8/1947 Torrance 242/47-05 are provided for regulating rotation of the drum and 2,469,767 5/ 1949 242/47'07 disc in dependence of the degree of winding. 3,419,225 12/1968 Rosen 242/47.l2 3,709,444 1/1973 Tannert 242/4704 27 Claims, 4 Drawing Figures if F zzj [I Z] 7 r 17 i 20 r I I US. Patent Dec. 9, 1975 Sheet 1 of4 3,924,818
US. Patent Dec. 9, 1975 Sheet 2 of4 3,924,818
US. Patent Dec. 9, 1975 Sheet 3 of4 3,924,818
US. Patent Dec. 9, 1975 Sheet 4 of4 3,924,818
THREAD STORAGE DEVICE BACKGROUND OF THE INVENTION The present invention is directed to the feeding of yarn or thread to knitting, hosiery machines and the like, and in particular to a method and apparatus for accumulating thread drawn from a supply on to an intermediate store, from which the thread can be further passed to a processing point.
Such intermediate or temporary accumulators ensure the supply of thread with considerable uniformity, independently of the initial supply, especially when the demand for thread is not continuous but intermittent. The drawing off of the thread can then take place under very generally constant and stable conditions from a relatively small supply of the intermediate or temporary store, rather than from the larger source.
In known devices of this kind (e.g. US. Pat. No. 3,419,225 a revolving cylindrical intermediate store draws the thread from the supply and winds it into an intermediate supply bobbin or the like. The quantity of the intermediate supply bobbin is kept within a desired order of magnitude determined by a scanning sensor, which selectively actuates means for connecting and disconnecting the operation of the intermediate store. The thread which runs tangentially to the intermediate store is subjected to tensile stress, which is produced inter alia by a thread brake preceding the store. The thread, which may be non-uniformly stretched, is wound on the intermediate store, creating a coil of thread which is then completely under this stress. This thread tension can if necessary be maintained as far as the thread processing point, however, the relaxation which is then permitted it, causes irregularities in the knitted goods. This danger is in particular present when the intermediate accumulator is used for the so-called positive supply of thread, i.e. if the same quantity of thread is drawn from it tangentially as was previously wound by it on itself. (See for example US. Pat. No. 3,720,384). The coil of thread under tension has another disadvantage when the intermediate store is used for the so-called negative thread supply, i.e., where quantities of thread are drawn off it axially and where it does not at the same time wind on itself. In addition to the drawback of having the thread under a longer duration in the state of tension, irregularities arise on removal of thread from the intermediate lap which is also under tension.
It is an object of the present invention to provide a method and apparatus in which these defects are remedied and which ensures that the coil of thread on the intermediate store is built up from a thread which is not itself under the uneven stresses produced by the winding operation.
In well known thread feeders, switching devices are actuated as a function of the respective thread supply for switching the driving motor on or off, (see US. Pat. No. 3,419,225) Sensing arms, racks tiltably discs or wheels are provided, which according to the oblique position imparted to it by the coil of thread, actuates a switch in the feeding circuit of the motor.
It is furthermore known to provide, between the thread winding drum and its drive, a clutch which can be engaged and disengaged. The clutch is controlled by a member sensing the state. of tension of the thread running off the drum in such a way that the thread winding drum is connected with its drive or separated from it 2 according to the respective thread requirement (German Pat. No. 834,581). It is also known from German AS 1,585,073 to employ a slip clutch so that the speed of rotation of thread winding drum is matched to the varying thread requirement.
In GB Pat. No. 1,295,734 there is arranged a loading member having several thread guide grooves, spaced laterally from the thread winding drum and parallel to the axis of the latter. The multiply guided thread, (alternately from the thread winding drum to the loading member and back to the drum) is finally placed by the loading member on to a conical portion of the drum from which it slides on to a cylindrical portion consisting of transparent material, on which a coil of thread is then formed. This coil is sensed by a beam projected by a source of light which passes through the transparent portion of drum from outside and runs directly towards a photo-sensitive cell stationarily arranged inside the drum. The cell controls electrical components which in turn actuate mechanical gears, which alter the speed of rotation of the thread winding drum in such a way that while maintaining a stored quantity of thread, the thread requirement is matched to the thread take-up.
In the well known feeders referred to, control devices which are sometimes of a very costly nature for varying the rotation of the thread winding drum in accordance with the thread requirement are necessary.
It is therefore, also an object of the present invention to provide thread accumulating and take-up means which is simple in construction, and easy and economical to run.
Further objects and advantages will be apparent from the following disclosure of the present invention.
SUMMARY OF THE INVENTION According to the present invention a method and apparatus is provided for accumulating and feeding thread from a supply thereof to a processing station wherein a rotating cylindrical intermediate storage member is provided and the thread is initially passed onto the peripheral surface of the storage member from the supply over the peripheral edge of a conjointly rotating disc having an axis oblique to that of the cylindrical storage member and is thereafter withdrawn to the processing station. The disc functions also, because of its oblique position, in relation to the storage member, to have its lateral face engage the thread causing the thread to wind on the peripheral surface into a coil and to act on the last wound section to move the coil axially on the peripheral surface toward the withdrawal position. The disc and storage means are preferably rotated at the speed at which the thread is withdrawn from the storage member. The rotation of the storage member and the disc is preferably effected by an electric motor which stator and rotor parts are integrally formed with the respective parts of the accumulator mechanism.
In the general form of the invention, the storage member comprises an open ended cylindrical drum having longitudinal slots extending axially on its jacket and the disc has radially extending teeth which respectively engage and extend through the slots. Further, the disc is mounted at the open end of the drum about an axis which is inclined and laterally offset from the axis of the drum so that the disc rotates in a plane oblique to that of the drum.
In one form of the invention, the drum is axially movable with respect to the disc which is fixed, and the drum is carried by a rod which is indirectly mounted to the machine, allowing the drum to axially move in response to the degree of winding of the coil. The movement of the drum which may be effected by the weight and centrifugal motion of the thread or drum, as well as the number of turns in the wound coil, is sensed and in response thereto a switch can be activated, in the circuit of the drive motor, which controls the motor. Thus, if too much thread is wound the motor can be slowed or stopped until a sufficient length is removed to the processing station.
In another form of the invention the drum and disc may be fixed against axial movement with respect to each other and the electric drive motor is of the type which is reponsive to changes in torque or drag load placed on it. A constant torque variable speed motor is preferred. Here the winding thread automatically and by itself regulates the operation of the motor and consequently the accumulation of the thread on the storage member.
Complete details of the present invention are set forth in the following description of several embodiments and are shown in detail in the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS In the drawings:
FIG. 1 is a side view in section of an intermediate or temporary storage accumulator according to the pres ent invention;
FIG. 2 is a view of the intermediate storage unit of FIG. 1 from above partially in section;
FIG. 3 is a view similar to FIG. 1 of a further example of the invention being in section along the line III-III in FIG. 4; and
FIG. 4 is a top view of the embodiment of FIG. 1 in section along the line IVIV of FIG. 3.
DESCRIPTION OF INVENTION The intermediate storage accumulator shown in FIGS 1 and 2 comprises a trough or channel shaped support bracket 1, closed by a lid 2. The bracket is attached by suitable bolts etc. so as to extend cantilevered from the wall of a thread processing machine, such as a knitting machine. Adjacent the free end of the bracket, a screw bolt 4 secures an elongated hollow shaft 5 depending in perpendicular relationship to the plane of the bracket. The shaft 5 forms the central bearing column for a coaxial, open ended cylindrical thread storage drum 6 and the means by which an electric motor 7 is attached within the pot-shaped drum 6.
The bottom of the drum 6 is provided with ventilation holes 6a for airing the motor and a cetral hole from which extends a tubular hub 8. Inserted within the hub 8 is an elongated sleeve bushing 9, the inner surface of which comprises the race or bearing surfaces of a pair of spaced antifriction bearings. The first bearing is a needle bearing 10 located within the drum 6 so that its inner race is provided-directly by the outer surface of the shaft 5. The second bearing is a ball bearing 11, the balls of which run in a grooved race formed in the bushing 9, and in an opposing grooved race formed on a cup bushing 12 carried on the end of the shaft 5. The cup bushing 12 is slidable with respect to the end of the shaft 5 and is provided with a suitable sliding agent applied to the adjacent wall surfaces of the shaft and bushing. The agent may be a lubricant, or it may be a suitable low friction member formed of Teflon or the like. The slide mounting enables the axial movement of 4 the cup bushing 12 with respect to the free end of the shaft 5.
Extending freely through the hollow shaft 5 is a holding rod 13, which is secured at its lower end to the axial face of the cup busing 12. At its upper end, the rod 13 extends through the screw bolt 4 and is attached to the free end of a leaf spring 14 by an adjustablethumb screw 15. The free end of the leaf spring is forked as at 14a and the screw 15 thus enables the holding rod 13 to be axially as well as radially adjusted with respect to the spring 14. The leaf spring 14 is attached at its opposite end to a block 16 fixed on the supporting bracket 1 adjacent the end secured to the processing machine. Mounted to the bracket 1, beneath the leaf spring 14, and between the block 16 and rod 13, is an adjustable screw stop 17, in a suitable block, adapted to limit the movement of the leaf spring 14.
The free end of the leaf spring 14, extends beyond the rod 13 and overlaps the contact of an on-off switch 18, wired in the circuit of the electric motor 7. Switch 18 may be a micro-switch or other suitable device, and is in addition to the main motor switch, (not shown) which is operable by the machine operator to control the motor 7.
The motor 7 surrounds the shaft 5, which is provided with a lower shoulder 19. The motor 7 comprises a stator having a fixed core 20a wedged between the shoulder 19 and the bottom of bracket 1, a stator winding 20b having a central axis angularly offset from the axis of the shaft .5, and a rotor 200. The rotor 20c is mounted at each of its upper and lower ends in the outer race of a ball bearing, the inner race of which is fixed to the core. The rotor 20c comprises a cylindrical member, having a magnet means or the like on its inner surface parallel spaced opposite to the windings 20b so that it rotates about the angularly offset axis of the windings. Secured to the upper end of the rotor 20c in a plane perpendicular to the motor axis is a toothed disc 21 having a plurality of widely pitched teeth 22 extending into respective longitudinal slots 23 formed in the cylindrical jacket of the thread storage drum 6. The teeth 22 and slots 23 create a relative positive and nonrotating coupling between the motor 7 and the storage drum 6.
It is evident from FIG. 1 that the axis of rotation of the rotor 20c and therefore also that of the disc 21 runs obliquely to the rotation axis of the thread storage drum 6 defined by the column 5. From this and from the outer diameters of the drum 6 and the disc 21 it will be seen that not all, but only a certain number of teeth 22 project at any one time through the apertures 23 be yond the external peripheral surface of the drum. The axes of rotation of the disc 21 and the drum are in addition to their inclination laterally offset in relation to one another, as is indicated by a projection of the axis of rotation of rotor 20c and disc 21 as represented by the dash-dotted line 24 in FIG. 2. The special significance of this offset will be dealt with in further detail below.
In the outer peripheral surface of the disc 21 there is formed a guide groove 25 receiving the thread denoted by a dash-dotted line F. The surface of the groove 25 can be roughened or otherwise treated as is suitable to obtain slip free engagement of the thread.
The thread F comes from a conventional supply component which is not shown. Before being placed in the part of the guide groove 25 protruding from the drum 6, as indicated at A it is first passed through a thread guide 26, which is attached to the support 1 which easily brakes the thread passing through it. The thread guide 26 consists, for instance, as shown, in the well known manner of two discs or plates which are held against one another by a weak spring and which guide the thread between them.
The thread F is initially inserted by hand in the direction of the arrow (FIG. 2) through the thread guide 26, and at A into the groove 25. It leaves the groove 25 again at point B, since at this point the groove 25 engages the peripheral surface of the storage drum 6, and the thread is laid on the latter. Initially the thread is looped by hand several times round the storage drum 6 and then finally forced under a brake ring 27 which, as seen in particular from FIG. 1, surrounds the storage drum 6. The lower end of the drum 6 tapers outwardly forming a thread take-off cone 28. The ring 27 falls freely about the periphery of the drum 6 to the take-off cone and preferably consists of elastic material such as rubber plastic or the like. The ring 27 moves freely under tension of the thread and consists of material that is in itself elastic, e.g. rubber. During its movement to the thread processing point, which takes place approximately parallel to the axial direction of the drum, the thread cap easily brakes the thread between it and the drum 6.
The figures show the parts in a position which they occupy after the intial setting up by hand which has been described, at which time there is no appreciable supply of thread on the thread storage drum 6 and the additional on/off switch 18 for the electric motor is in the ON position.
In operation the main switch (not shown) is closed actuating the electric motor 7, causing its rotor 20c and therefore also the disc 21 and the drum 6 coupled with it to rotate, on the direction of arrow M in FIG. 2. The thread F which is taken from the not shown supply by the disc 21, is moved along without slippage on the disc 21 and is placed on the peripheral surface of the storage drum 6 at the point B (FIG. 2) which, because of the coupling, moves at the speed of the thread, the thread then being carried along by the latter. The thread F, which initially runs in the plane of movement of the disc 21, after being placed on the storage drum 6 runs in the plane movement of the drum which is angular to that of the disc. Due to the inclination of the axis of the disc and its lateral offset from the rotation axis of the drum 6, the result obtained is that the thread winds itself in a transverse plane on the drum 6 so that when the length of thread on the drum is rotated to again come into proximity to the zone A, it lies below the point at which the teeth 22 again begin to emerge from the peripheral surface of the lower lateral face 22a of the disc 21. This is illustrated by position marked in FIG. 1 at C. In the zone between A and B, the thread previously laid on the drum 6 will enter the path of movement of the lateral face 22a of the teeth 22, and since at this point the teeth already project by a considerably distance from the peripheral surface of the drum 6, the thread is forced by this face 22a to be moved axially downward on the drum 6. After a first revolution of the drum, the loaded thread is then at the point D (FIG. 1) of the drum 6 below the thread being dated that a point is reached in which the upper winding can no longer be axially moved on the drum, the coil being so tightly wound against the cone 28. When this occurs the upper most winding reacts against the lower lateral face 22a of the disc 21 exerting separating force between it and the drum. As a consequence the coil of thread and the drum 6 move axially conjointly in relation to the disc 21, along the rod 13 while still coninuing in rotative movement conjointly with the disc 21. The movement is accomplished easily by the described mounting of the drum 6 on the slidable cup bushing 12 which is connected via the holding rod 13 to the resilient spring leaf 14. When the coil winds about the drum 6, the drum is caused to sag or move downwardly pulling rod 13 with it. The rod 13 simultaneously pulls the leaf spring 14 into a position where its free end trips the normally closed contact of switch 18, breaking the circuit of the motor 7, stopping the winding of the thread on the drum from the source.
The size of the coil stored onthe drum and the moment of switch-off can be determined simply by appropriately dimensioning the leaf spring 14, by selectively setting the adjustment screw 17 and the thumb 15. Furthermore, the sensitivity of the device may be selectively affected by the ease of running of the sliding joint between the colum 5 and the cup bushing 12 and by the weight of the drum 6. It is essential, to form the longitudinal apertures 23 of the drum axially longer than would actually be necessary for the engagement of the teeth 22, so that the drum 6 would be significantly lightened, if it is so desired.
Drawing off the thread F, to the processing station, reduces the supply of thread on the drum 6. Thus the resilient force of the leaf spring 14 can finally move the drum axially in relation to the residual coil of the thread supply engaging the disc 21, whereby the parts move back into the position represented in FIG. 1. The switch 18 which then enters the ON position closes the circuit of the motor 7 causing it and the drum 6 to be set in motion again, recreating a supply of thread on the coil in the manner previously described. There is thus available for take-off to the processing station a temporary supply which builds up automatically to an extent which can be determined and from which thread can be taken off continuously or intermittently. In the latter instance, of course, the quantity delivered by the drum 6 must be greater than the thread consumption.
The device represented can be used without difficulty for the so-called positive supply of thread, where the quantity of thread passed to the drum 6 corresponds more or less exactly to the amount to be passed by it continuously to the processing station. The thread is supplied and wound about the drum similarly as described with respect to FIG. 1,. but at the same time the thread is not as represented in FIG. 1 moved axially to the take-off position of the processing station, but instead, as is shown in FIG. 2, is taken-off in a direction F tangentially away from the drum and substantially in a parallel plane to the in-feed direction F. Thus a relatively small supply of thread need be wound on the drum 6 which amount is by no means sufficient to cause an axial movement of the drum 6 in relation to the disc 21 and which moves at a speed sufficient to keep the drum 6 from falling by its own weight. The switch 18 therefore remains in its on position during the continued operation.
It may be seen from FIG. 2 that the thread F lies on a circular sector path between points A and B, which through the extension of the teeth 22 through the slots 23 is larger than the sector of the surface of the drum 6 from the point B at which it is loaded or laid on the drum and its take-off point. From this it will clearly be seen that the length of thread extending between the point A and B is longer than the peripheral length of the surface of the drum 6 which is in the same Zone. Hence it follows that for the thread F, a loading length is available on the surface of the drum 6 for it to wind which is shorter than the length of thread removed from the supply for it. Therefore, should thread, taken from the thread supply and passed through the thread guide 26, be even slightly stretched, it can on reaching the point B, be relieved of stress on being loaded on the drum 6. The degree of difference between the circular path AB in the groove 25 and the circular path AB on the surface of the drum 6 depends, on the diameter of the groove 25 and of the drum 6 as well as on the angle of inclination of the rotation axes of these two numbers to one another, and on the lateral offset between the rotation axes of the disc 21 and the drum 6. The arrangement is preferably made in such a way that on the one hand the adequate relaxation of the thread F can be obtained, while on the other hand, the thread F is not wound so that it surrounds the drum 6 so loosely thereby producing a supply coil which is not adequately rigid to prevent the axial movement of the drum 6.
If the rotation axes of the disc 21 and the drum 6 were merely to run inclined to one another, and with reference to the representation in FIG. 2, a projection of the rotation axis of the disc 21 would intersect the rotation axis of the drum 6, the result would be that those points at which the teeth 22 enter the peripheral surface of the drum 6, and leave it again, would lie on the same plane imagined as running at right angles to the rotation axis of the drum 6 through the latter. A thread laid by the disc on the drum, would then be covered by the disc emerging from the peripheral surface of the drum and lifted by the drum. The lateral offset of the rotation axes of the disc 21 and the drum 6 in relation to one another prevents this and of placing the point of entry of the groove 25 into the peripheral surface of the drum 6, viewed in the axial direction of the drum 6, closer to its take-off cone 28 than that point on the peripheral surface of the drum 6, at which the teeth 22 of the disc 21 again begin to emerge from the peripheral surface. A thread F from the groove 25, laid on the drum 6 in which it is overlapped by the teeth 21 protruding again from the peripheral surface of the drum 6 must therefore certainly come into contact with the lower end surface 22a, whereby the formation of the intermediate storage coil described above is produced. By means of correspondingly large lateral offset, as represented, the result can be obtained that the point of entry of the groove 25 in the peripheral surface of the drum 6 is at a point where the groove 25 is at its shortest distance from take off cone 28.
The intermediate or temporary accumulator shown as a second example of the invention differs from that according to FIGS. 1 and 2 through its special driving means, which dispense with the use of switching mechanisms to be actuated by the respective thread supply for switching the motor drive on and off. Similar parts to those of FIGS. 1 and 2 are shown in FIGS. 3 and 4 by similar numerals increased by 100.
According to FIGS. 3 and 4, a wall 103 of a thread processing machine e.g. a knitting machine is adapted to carry a number of intermediate accumulators of which these figures show only a single one. In its support 101, placed on the wall 103 and fixed to it by a clamping screw, is attached a shaft 29 by means of a screw fitting 104. 0n this shaft 29 there is supported in an antifriction bearing 30 a loading member which is generally denoted by numeral 36, having a loading disc 121 which, as apparent from FIG. 4, is toothed and whose outer peripheral surface has a peripheral guide groove cut in it, (vide also FIG. 3), as previously described.
A second shaft 31 is fastened in a threaded bore 290 in the shaft 29, with the help of a thread attachment. As may be seen from FIG. 3, this attachment is carried out in such a way that the shafts 29 and 31 run inclined with respect to one another, and from FIG. 4, it may be seen that the direction of the threaded bore 29a is eccentric in the shaft 29, whereby there is created a lateral offset of the two shafts 29 and 31.
The stator 32 of an electric motor is attached on the shaft 31. The rotor is fixed on roller antifriction bearings 33 on the depending shaft 31. The main connecting cables for the stator 32, which are not shown, run in a duct 34 formed in the shaft 29. the rotor comprises at the same time the thread storage drum 106, whose cylindrical surface is provided on the end facing the loading disc 121 with longitudinal apertures 123, into which the teeth of the loading disc 121 can enter. Preferably the rotor and stator comprises electric motor means employed in this embodiment, one having a relatively constant torque so that it may respond to changes in torque created by the thread at any speed.
The diameters of the thread storage drums 106 and the loading disc 121 are selected in such a way and the shafts 29 and 31 are so offset in relation to one another that the loading disc 121, over a portion of its periphery, protrudes from the surface of the thread storage drum 106 and the remaining part of the periphery runs within the drum 106. Through the engagement of the teeth 122 of the loading disc 121 in the longitudinal opening 123 of the drum 106, there is a simultaneous rotation of the loading disc 121 during the rotation of the drum 106.
A thread denoted by the dash-dotted line F is passed via a thread brake 126 arranged in the support 101 and then to the loading disc 121. It is initially placed by hand in the latters groove 125. The thread F, as may be seen from FIG. 4, during looping at the point B, bears on the surface of the drum 106 round which it is laid several times and is finally taken via a thread take-off cone 128 axially to the processing station. At the same time, the thread is passed between the drum 106 and a brake ring 127, which consists of material that is itself elastic.
On initiating operation of the machine, with simultaneous switching on of the motor (32, 106), the drum 106 and the driven loading disc 121 revolve in the direction of the arrow 34 (FIG. 4). At the same time, the oncoming thread F lying in the groove 125 of the loading disc 121, reaches the point B where it loads itself on the thread winding drum 106. Due to the inclination of the axis of the drum 106 to the axis of the disc 121 it has been found that when the loaded thread on the drum is moved below Zone A it is axially below the point at which the teeth 122 of the disc 121 begin to emerge from the surface of the drum 106. The end surfaces of the teeth 122 facing the thread then come into contact with the thread in the range of movement between the points A and B and shift it axially on the cylindrical surface of the drum 106. After a further revolution of the drum the thread previously placed at the point B has moved axially to the point denoted in FIG. 3 by the arrow D. The thread which reaches this point D pushes the thread previously located at this point axially on the drum and in this way there is formed on the drum a coil consisting of a plurality of turns, which rests for its axial movement on the drum 106 on the loading disc 121, which is at the same time the supporting member. The force needed for the axial shift of the coil of thread increases in accordance with the growth of the coil and attains orders of magnitude that are higher than the force which was originally necessary for the rotation of the device. This force which is needed for the axial shift of the coil, has to be provided by the electric motor (32, 106). As a result the motor reduces its remaining force for the rotation of the drum, and according to the level of the power limit of the motor, the latter is caused to run more slowly and may even be brought temporarily to a standstill. Due to the subsequent thread take-off which occurs, the force to be expended for the axial movement of the coil of thread is reduced, so that the motor starts up again, or in accordance with the thread take-off runs faster and thus adapts itself automatically to the respective thread requirement, while maintaining a supply of thread on the drum 106.
The size of the thread supply depends on the power given to the motor and in order to be able to determine the size of the thread supply, the motor power can be influenced by simple means by being operated either with its rated voltage or at a voltage lower than the latter. In accordance with the reduction in the rated voltage, the size of the thread supply coil is reduced since the motor attains its power limit earlier. In this embodiment moreover the nature of the thread is important, for the frictional resistance of the coil of thread during its movement on the drum depends on the type of thread and since the speed of rotation is influenced by the extent to which the power required for the axial movement of the thread coil increases or decreases, only that power requirement, but not the size of the coil is really decisive. Influence is moreover exerted by the degree of thread braking, i.e., the respective setting of the thread brake 126, on the size of the thread supply coil.
For altering the voltage, well known arrangements may be made, e.g., an adjustable transformer can be arranged in the feeding circuit, or other variable voltage regulators supplied.
The embodiment shown in FIGS. 3 and 4 have considerable advantage.
Simplification over the devices heretofore known is obtained by the fact that the disc is formed as a fixed supporting member for the coil of thread which moves opposite it axially on the storage drum. As a result special scanning or sensing members and arrangement for their movable support can be dispensed with. Furthermore, the switching mechanisms that are otherwise actuated by those moving parts, such as the drum and disc, can be dispensed with through the use of the constant torque electric motor, since in accordance with different power requirements, the motor alters its speed and can if necessary, temporarily come to a standstill without actuating a switch. The use of the electric motor with roughly constant torque within the speed range in question has the special advantage that the device responds to changes of torque at any speed in about the same way, i.e., it adapts itself automatically and constantly to thread requirement of an extensive nature, while maintaining an approximately constant supply. Such adaptation is not, however, furnished by types of motor with greatly varying torques depending on their speed of rotation, since with thread requirement of different extent, due to their correspondingly different torques they would form thread supplies of different size and thus not render possible the withdrawal of thread from a supply that is always approximately the same, as is aimed at for feeders.
This device is thus based on the principle of using, as
a gauge for the direct influencing of the drive of a feeder, the force that is needed for moving a thread supply coil mounted at a point forming part of the apparatus and moving on a storage surface that likewise forms part of the apparatus.
Various changes, modifications and embodiments have been described. It is intended therefore, that the present disclosure be taken as illunstrative only of the invention and not as limiting of its scope or application.
What is claimed:
1. A method for accumulating and feeding thread from a supply thereof to a processing station, comprising the steps of providing a rotating cylindrical storage member, initially passing said thread from the supply to the peripheral surface of said storage member on the peripheral edge of a conjointly rotating disc having an axis oblique to that of the storage member, arranging said disc with respect to said storage member so that its lateral face engages said passing thread urging it to wind on the peripheral surface of said storage member into a coil and thereafter urging said coil to move axially on the peripheral surface of said storage member and simultaneously withdrawing the thread from said storage member to said processing station.
2. The method according to claim 1, wherein said storage member and said disc are rotated at a speed equal to the speed at which said thread is withdrawn.
3. Apparatus for the intermediate accumulation of thread being delivered from a supply thereof to a processing station comprising a disc rotatable about its central axis having a peripheral edge for receiving thread from said supply, a cylindrical storage member rotatable about its central axis having a peripheral surface on which said thread is wound, said disc being arranged adjacent one edge of said storage member, having its axis of rotation inclined to and laterally offset from the axis of rotation of said storage member and its peripheral edge extending radially beyond at least a portion of the peripheral surface of said storage member, means for conjointly rotating said disc and said storage member, said peripheral edge having a lateral face adapted to urge said thread to wind about the peripheral surface of said storage member into a coil and to urge said coil to move axially along the peripheral surface of said storage member to the upper end of said member for withdrawal to said processing station.
4. The apparatus according to claim 3, wherein said thread is withdrawn from said storage member and means are provided for rotating said storage member and said disc at a speed equal thereto.
5. The apparatus according to claim 3, wherein said peripheral edge of said disc is provided with a groove for receiving said thread.
6. The apparatus according to claim 3, wherein said storage member and said disc are axially movable with respect to each other, in response to the winding of said thread into a coil.
7. The apparatus according to claim 6, including means for sensing the axial movement of said disc and storage member and in response thereto controlling the means for rotating the same.
8. The apparatus according to claim 3, wherein the means for rotating said storage member and said disc comprise an electric motor having a rotor and a stator, the rotor being connected to said disc and the stator being fixedly mounted within said storage member.
9. The apparatus according to claim 3, wherein said storage member is rotatably mounted about a fixed shaft, and said means for rotating said disc and storage member comprises an electric motor, the stator of which is mounted on said shaft within said storage means about an axis inclined with respect to and offset in relation to the axis of the shaft, said disc being mounted on the rotor of said motor in a plane perpendicular to the axis of said stator.
10. The apparatus according to claim 3, wherein said storage member comprises a drum mounted to rotate about a given axis, said drum being open at one end and provided with a plurality of longitudinal slots extending axially from said open end and said disc is mounted within said drum about an axis inclined with respect to and laterally offset from the axis of said drum, said disc having an outer periphery formed of a plurality of teeth extending respectively through said longitudinal slots.
11. The apparatus according to claim 10, wherein said drum is axially movable with respect to said disc in response to the winding of said thread thereon.
12. The apparatus according to claim 10, wherein said drum is provided with a conical take-off member for passing the thread to the processing station.
13. The apparatus according to claim 11, wherein the axially movable drum is held by a spring in one of its end positions, its axial movement taking place against and under the action of the spring, a switch member located adjacent said spring for providing switching pulses for the motor in response to movement of said spring.
14. The apparatus according to claim 13, wherein the drum is attached to a supporting rod which is carried so as to be axially movable in the shaft, which rod is held by said spring in one of its end positions.
15. The apparatus according to claim 14, including a support bracket and wherein the spring is a leaf spring fastened at one end to said support bracket and free at its other end, said holding rod being attached adjacent to the free end of said leaf spring.
16. The apparatus according to claim 15, wherein the leaf spring in the area between its support and the point of attachment of the holding rod is provided with an adjustable stop.
17. The apparatus according to claim 16, wherein the switch is arranged adjacent said leaf spring within the zone of movement of the leaf spring so that it can be actuated on movement by said leaf spring.
18. The apparatus according to claim 14 including fastening means for fixedly attaching the shaft to said support bracket, said fastening means comprising the fastening for the leaf spring.
19. The apparatus according to claim 3 wherein the diameter of the disc and the diameter of the storage member and the inclination and lateral offset of the rotation axes of disc and storage member relative to one another are chosen such that the point of entry of the 12 peripheral edge of said disc in the surface of the storage member, viewed in the axial direction of the storage member is closer to the other end of said storage member than that point on the surface of the storage member at which the teeth of the disc start to emerge from it again.
20. The apparatus according to claim 3, wherein the storage member and said disc are axially fixed with respect to each other, and said rotating means comprises an electric motor having a constant torque within a given speed range, the winding of the thread into an increasing coil on said storage member creating a drag on the rotation thereof causing a counter torque within said motor correspondingly reducing the speed of rotation thereof.
21. The apparatus according to claim 20, wherein said motor is operated at a voltage lower than its rated voltage.
22. Apparatus for the intermediate accumulation of thread being delivered from a supply thereof to a processing station comprising a supporting bracket, a hub having a central axis fixedly mounted on said support, a disc rotatable mounted about said hub concentric with the central axis thereof, a shaft fixed to said hub and extending along an axis oblique to and laterally offset from the axis of said hub, a cylindrical storage member rotatably mounted about said shaft, means for conjointly rotating said disc and said storage member, said storage member having a peripheral surface upon which said thread is wound, said disc having a peripheral edge for receiving thread from said supply and for passing said thread unto said peripheral surface of said storage member, the peripheral edge of said disc being adapted to urge said thread to wind about said storage member into a coil and to urge said coil to move axially along the peripheral surface of said storage member away from said disc to the other end thereof for withdrawal to said processing station.
23. The apparatus according to claim 22, wherein said storage member comprises a substantially hollow drum open at one end and provided with a plurality of longitudinal slots extending axially from said open end and said disc is mounted about said hub to lie within the open end of said drum, said disc having an outer periphery formed of a plurality of teeth extending respectively through said longitudinal slot.
24. The apparatus according to claim 23, wherein each of said teeth is provided with a groove on.its outer end, the locus of which lie about the axis of rotation and form the peripheral edge of said disc.
25. The apparatus according to claim 23, wherein the means for rotating said storage member and said disc comprises an electric motor in which the storage member comprises the rotor thereof and includes a stator attached to said shaft.
26. The apparatus according to claim 25, wherein said storage member and said disc are axially fixed on said hub and shaft respectively and said motor has a constant torque within a given speed range, the winding of the thread into an increasing coil on said storage member creating a drag on the rotation thereof causing a counter torque within said motor correspondingly reducing the speed of rotation thereof.
27. The apparatus according to claim 26, wherein said motor is operated at a constant voltage lower than its rated voltage.