Fig. 138.J.N.
Fig. 138.J.N.
(247) To overcome this defect, therefore, the motion has been re-arranged in one or two cases, so that all the parts revolve in the same direction. Messrs. Curtis, Sons, and Co. employ Curtis and Rhodes’ motion, which is illustrated in section in Fig.138. The bobbin wheelAis cast in one piece with, or fixed to, an internal wheelC, which is loose upon the shaftB. The discDis fastened on the shaft, revolving with it, and carrying a pin or spindle, on each end of which are fastened the pinionsEandF.Egears with the internal wheel, andFwith a compound pinionG, which in turn engages with the pinionH. The latter iscast on the collarL, which is driven from the lower cone and is loose upon the shaftB, revolving in the same direction. If the collarLis fastened to the shaft, the whole of the wheels become locked together, and the bobbin wheelAand the driving pinionHwill revolve together at the same speed and in the same way. This arises from the fact that the discDis fixed on the shaft, and as it carries the train of wheels the fastening ofLkeeps the teeth ofEandFlocked, so causing the rotation of the latter and its attached wheelA. The carrier wheels would be standing under these conditions, while the Holdsworth motion in the same circumstances would have the whole of the wheels in rapid motion. Thus, if in actual work, when the collarLis loose, it is revolved at the same speed as the discDor at one nearly approaching it, there would be no motion in the carrier wheels, or very little, and the speed ofAwould equal that ofH. As the velocity of the latter is reducing, more motion is given to the wheels, which thus retard the wheelAwhile allowing it to rotate in the same direction as the shaft. In this way the wear and tear of the parts, and the power required to drive them, are alike materially reduced.
Fig. 139.J.N.
Fig. 139.J.N.
(248) Messrs. Howard and Bullough use Tweedale’s motion, which is illustrated in Fig.139. The shaftAhas a boss fastened on it, which is constructed with a second bossGat right angles to, but on one side of it. The latter is bored to receive a short shaft, on each end of which the two wheelsF Hare fixed. The wheelBis driven from the lower cone, and is compounded with the bevel wheelE, both being free to revolve on the shaft. The bobbin wheelCis cast in one piece with the wheelD, and also runs loosely upon the shaft. It will be noticed that only the wheelsFandHare positively rotated on the shaftA, being carried round with the boss. The motion is communicated fromEtoDas follows:Edrives the wheelF, thus rotating the short cross shaft and the pinionH. The latter gears with and drives the wheelD, the pinionFacting merely as a carrier. The action of this mechanism can be readily understood from the preceding explanation, and it need only be pointed out that the regulation comes from the wheelB. There is introduced into this mechanism the element of a double set of driving and driven wheels. ThusGdrives the wheelF, andH D, so that there is a difference between this and the Holdsworth motion, in which the intermediate pinions act as carriers only. In order,therefore, to get the speed communicated to the wheelD, it is necessary to multiply the number of teeth in the driving wheels and divide by those of the driven, by which means the proportions of the two are arrived at. By the use of the following formula the speed ofDcan easily be arrived at. Letm= revolutions of the shaft,n= revolutions of the pinionB, which is variable,a= the constant arrived at as above, andv= the speed of bobbin wheelD, thenv=m-a(m+n). Having obtained the speedvit is of course easy to calculate the necessary wheels to give the speed of the bobbins.
(249) The operation of the differential motion is controlled, as has been seen, by the lower cone, the speed of which is carefully regulated by altering the position of the driving strap laterally. It has been pointed out that the cones are correspondingly but conversely curved, the reason for this being that the actual increase which takes place in the diameter of the bobbin is not in the same proportion to the actual diameter at the end as at the beginning of winding. There is a slight decrease occurring as the bobbin fills, and in the early stages of spinning it was the practice to use a rack with uneven teeth cut to a parabola, which was a costly process, and is entirely avoided by the use of cones of that shape. Further, it is found that the bite of the strap is better during a change of position. It will be readily understood that the position of the strap on the two cones determines the speed of the plate wheelL. It is therefore essential to provide means by which the traverse of the strap can be effected, and, as the addition of one layer of roving implies the necessity for a change in the bobbin speed, the movement of the strap is given at the termination of each lift, at the moment of the change of traverse. It follows, therefore, that the mechanism by which the strap is moved, and that by which the reversal of the lift is effected, must be connected. Before proceeding to describe how this is done it may be stated that the strap passes between two guides fastened to the toothed rack or slideP(Fig.134), sustained by bearings fixed to the frame of the machine. The operation of traversing the rack is performed by an interesting piece of mechanism which has several functions.
(250) The “building motion,” or “box of tricks” as it is sometimes called, is placed in the position shown in Fig.133by the letterQ. In order that its details may be better understood, a front and back elevation and plan of it is given in Figs.140,141, and142, to which special reference will be made. The objects of the building motion are three-fold: 1st, to give the requisite traverse to the cone strap; 2nd, to give the reciprocal traverse to the bobbin; and 3rd, to shorten that traverse or lift at the termination of the winding of each layer. It has been already explained why the two first objects have to be attained, and it will be profitable to explain the reason for the third. Suppose that in commencing winding the tube is 11⁄4inches diameter, the lift say 10 inches, and the diameter of the roving1⁄8inch, there would be wrapped upon that surface during one lift 80 coils or 314 inches of roving. Now, assuming that four layers have been wound, the diameter of the bobbin would be 21⁄4inches, which, if the lift remained constant, would cause 563 inches to be wound on the surface. But as the rate of delivery by the rollers is definite during the time occupied by the lift, it follows that such a length of roving could not be wound. It, therefore, becomes necessary to reduce the lift after each layer of yarn is wound, so as to compensate for the increased area of the cylindrical surface, and provide that the whole of the length delivered by the rollers is taken up, but no more.
Fig. 140.J.N.
Fig. 140.J.N.
(251) Referring now to Figs.140and141it will be noticed that there are two cradlesAandB, centred respectively on the pinsA1andB1. Fixed in the upper cradleAare hooks, one at each side, which are connected, as shown, with double hooksC D, passing through ears on the lower cradleB, having weights attached to their lower ends. The lower cradleBhas fixed in it a pinE1, engaging with a slot in the leverE.Eis centred on the pinF, and is coupled at its lower end to the rodR, which is connected with the double bevel wheelT T, this connection being shown in Fig.134. Two catchesG G1, centred at their lower ends to the frame carrying the cradles, are coupled by the helical springH. It will be noticed that the pawls of the catch levers are differently shaped, so as to engage with the teeth of the rack or ratchet wheelIon the upper and lower side of the centre respectively. The rack wheel is fixed on the same centre as the cradleA, as is also a bevel pinionJ, gearing with a similar oneJ1fixed on the upright shaftK, Fig.141. At a higher point onKa spur pinionP1is fastened, which gears with the teeth on the rackP, controlling the strap guides. Two leversL L1are pivoted to the frame as shown, and are coupled at their inner ends by a helical springM, which is carried round the centreB1. The inner ends ofL L1engage with shoulders or cornersNN1, formed in the lower cradleB. Fixed to the bobbin rail is the double slideQ, which has a pinOsliding in it, on which the end of the connecting rodSis centred. This rod passes through bearings placed in the cradleA(see Fig.140), and is formed with a toothed rack at its lower side with which a wheelTfixed on the pinA1gears. These are the whole of the parts of this particular mechanism, but a reference to Fig.134will show that the rackPhas a weight attached to it by a chain, which is always tending to draw it inwards, and move the strap. In addition to this it causes a torsional strain to be exercised on the shaftK, and consequently on the rack wheel, which causes the latter, when released by the catches, to rotate.
(252) The action of this mechanism is as follows: The slideQin its reciprocal vertical movement causes by means of the “diminishing rod” or “hanger bar”S, the upper cradleAto oscillate in its centre. When the bobbins are midway in their lift, the centre of the slideQshould be in a line drawn horizontally through the centre of the pinA1, and the rodSshould be capable of being moved horizontally without producing any oscillating movement in the cradleA. When this is the case, the two leversL L1engage respectively with the shouldersN N1. Assuming that the bobbins are descending, the cradleAis turned from left to right when looked at from the back of the frame as in Fig.141. In this way the hookDis raised with its pendant weight, whileCis simultaneously lowered. As the shoulder on the upper part of the hookCprevents it passing through the hole in the ear on the cradleB, it follows that a pressure is exercised on the latter, which causes it to turn in the same direction asA. The weight attached toDis finally completely taken off the cradleB, and the continuance of the movement causes the point of contact ofLandNto become the fulcrum by which the rotary movement ofAis arrested for the time. This movement closely resembles the action of an anchor, the cradleBbeing practically fixed as a ship is by its anchor. In some modifications of the mechanism this resemblance is more pronounced than in the one immediately under notice. Thus the point through whichDpasses continues to be free, while the whole weight is thrown upon the hookC, which thus exercises a proportionate strain onB. The continued oscillation ofAin the direction indicated causes the screwX, fixed in the left hand arm ofA, as shown in Fig.140, to come into contact with the outer end of the leverL. The increasing pressure so applied causesLto turn upon its centre, destroying the contact of its inner end with the shoulderN, and allowing the cradleBto make a sudden movement, which is partially rotary, but is also vertical in character. The movement being reversed, the parts assume the position shown in Fig.140, shortly after the reversal. The screws fixed in the arms of the cradleAcan be readily adjusted and locked so as to make the release of the lower cradleBsimultaneous with the termination of the bobbin traverse.
Fig. 141.J.N.
Fig. 141.J.N.
Fig. 142.
Fig. 142.
(253) In consequence of the sudden release so effected, the leverL1assumes the position shown in Fig.140, and at the same time the pinE1strikes one side of the hole in the leverE(see Fig.141), and causes the latter to turn rapidly on the pinF. This is followed by three things. The head of the leverEstrikes the catchG1and throws it out of gear with the ratchet wheel. The latter at once makes a rotary movement to the extent of half a tooth, but is then arrested and retained by the catchG. As the catch leversG G1are coupled by the springHit will be easily understood how the movement of one of them to the right or left is accompanied by a corresponding movement of the other. By this release of the ratchet wheel and its partial revolution, the uprightshaftKalso moves and causes the rackPto travel inwards and so move the strap on the cones. This is the first effect of the movement of the leverE.
(254) As shown in Fig.134, and also in Fig.141, the lower end of the leverEis attached to the rodR, which is connected at its other extremity by a forked lever to the double bevel or “striking” wheelT T1. The latter engage alternately with the small bevel pinion fixed on the lower end of the upright or “change” shaftMand slide upon a short shaftU, which they drive by means of a feather key. OnUis also fixed a spur pinionVwhich drives, by the intervention of suitable gearing, a shaft running longitudinally and placed just behind the spindles. This shaft has a number of spur pinions fixed on it, which engage with vertical racks or “pokers” fastened to the bobbin frame. In this way the rotation of the pinionVin either direction is followed by the traverse of the bobbins either upwards or downwards. When, therefore, the rodRis traversed by the oscillation of the leverEand the bevel wheelsT T1are respectively thrown into gear with the pinion onM, the bobbin traverse in a corresponding direction is obtained.
(255) A further effect which arises from the rotation of the ratchet wheel is found in the fact that the wheelT(Fig.140) also moves, and as it engages with the rack on the underside of the rodSdraws the latter inward. As will be readily understood, the position of the pinOplays an important part in the oscillation of the cradleA. If, for instance, the pin were at the extreme point ofQfurthest fromA, the motion of the latter would be made much more slowly than ifOwere at the other end of the slide, when, owing to the shorter radius,Awould make its oscillatory movement more quickly, and, ifQmade the same vertical traverse,Awould move through a greater arc. Thus, ifOis drawn inwards, it is followed by a more rapid movement of the cradleA, and, as a consequence, the change of the position of the leverEoccurs at an earlier moment. This causes the reversal of the traverse of the bobbin rail to take place sooner, and, in this way, each succeeding layer of roving occupies a shorter portion of the bobbin surface longitudinally than its predecessor. Thus the bobbin is built accurately in the double conical shape required, and the shortening of the lift, the necessity for which has been previously demonstrated, is properly effected.
(256) A reference to Fig.134will show that the weight attached to the rackPis fastened to the latter by a chain, which passes over a pulley at the lower end of the leverW, which is sustained in position by a catch placed atX. When the rackPhas made its extreme inward traverse the catch is released, and the leverWis caused to strike the collar on the rodY, so as to cause the latter to move longitudinally. As the rod is connected with the driving strap fork, the strap is thrown over on to the loose pulley, and the frame is stopped. Attached to the bobbin frame are chains, to the other end of which balance weights are fastened so as to relieve the work of the lifting pinions. These chains are passed over pulleys fixed to the framing as shown in Fig.134.
(257) Recurring now to the action of the building and winding motions, it is necessary to note that the number of the releases of the ratchet wheelIcorrespond to those of the reversals of the bobbin rail, and consequently to the number of the layers of roving. It therefore becomes necessary to alter the wheelIwhenever a change in the roving which is being produced is made. As the ratchet wheel is the governing factor in the regulation alike of the speed of the strap traverse and of that of the inward movement of therodS, the reason for changing it is easily seen. Thus the increase in the diameter of a bobbin on which a roving1⁄16th inch diameter is being spun would be less than that which occurs when a roving3⁄32nd inch diameter is made. It follows, therefore, that the rate at which the strap is moved along the cones would in the first case be only two-thirds of that at which it moves in the last case. Again, the lessened increase in diameter involves, as was shown, the winding on of a shorter length of roving during the “lift” of the bobbin, and consequently the latter does not require to be diminished in the same ratio. Therefore, it is desirable to substitute for the ratchet wheel one with more teeth, the number of which must be in direct ratio to the number of coils it is intended to wind on the full bobbin.
(258) Let it be assumed that the pitch of the teeth of the rackPand of that inSis one-quarter inch; that the ratchet wheelIhas 30 teeth, the pinion engaging withP31 teeth, and the pinionT19 teeth. As was shown, the wheelImoves to the extent of half the pitch of the tooth every time the traverse of the bobbin rail takes place. In this case 60 such reversions would take place during the time that the ratchet wheel made a complete revolution. During that time the wheel engaging withPwould also have made a complete revolution, andPwould have moved in 73⁄4inches, giving a corresponding traverse to the strap. In the same time the pinionTwould have made a revolution, and the “diminishing rod”Swould move in 43⁄4inches. Assuming—a purely hypothetical assumption—that the distance from the centreA1of the cradleAto the outermost point of the slideQto which the pinOcan be pushed is 15 inches, and that the lift of the bobbin be 7 inches, it will follow that the above reduction of the distance ofOfromA1will cause a more rapid oscillation of the cradleA. A simple calculation will show that this would cause the change of the direction of the lift to take place when 43⁄4inches was covered. This example will serve to illustrate the principle involved, but does not necessarily represent any actually existing case. It is only intended to show that the reduction of the lift takes place in exact accordance with the period occupied by the ratchet wheelIin its rotation. During the time the traverse has been shortened the speed of the bobbin, owing to the traverse of the strap along the cones, has also been diminished in the exact proportion required to compensate for the increased diameter.
(259) Now, if it be assumed that a coarser roving requires producing, and that the ratchet wheelIis changed for one containing only 20 teeth, it will be seen that while the same necessity exists for the full traverse of the strap guide and diminishing rod, a smaller number of layers of roving will be wound in the same time. In this case 40 layers only will be laid, although the strap makes the same movement. That is, the same reduction of the speed of the bobbin is made while 40 layers are wound that was previously made while 60 were wound. Now, as the diminution of the speed of the bobbin must be exactly proportionate to the increase of its diameter, it follows that the roving in the former case must be correspondingly thicker. It should also be observed that the inward traverse of the diminishing rodSis quickened as well as that of the racksP, because the time occupied by the ratchet wheel in making a complete revolution is, of course, less than when one with 30 teeth is employed. Thus the speed of the bobbin and the length of its traverse are both decreased at a more rapid rate when a ratchet wheel is employed, which is exactly what is wanted when coarser roving is being produced.
(260) A locking motion is fitted to the machine by which, when the rackPis released in the manner described, the stop rod is locked in such a way that until the rack has been wound back by hand into proper position the frame cannot be started. There are two advantages in this motion, viz., that the size of the bobbins is accurately regulated, and damage to the frame is prevented.
Figs. 143, 144, 145, and 146.
Figs. 143, 144, 145, and 146.
(261) In order to avoid the uneven wear of the top rollers, caused by the slubbing or roving passing through them at one point constantly, it has become the practice to give a slight lateral traverse to the guide bar. One of the latest developments of this special treatment is illustrated in Figs.143to147, this being the invention of Mr. George Paley, a spinner, of Preston. It consists of a wormIfixed upon the end of the roller spindle, which gears into two wheelsG H, carried on a pin fixed in a bracket. The number of teeth in the wheels are different,Hhaving one more tooth thanG. In this wayGis revolved once for every 24 revolutions of the worm, whileHrequires 25 revolutions of the latter before making a complete rotation. The wheelHhas a bossJ, the upper part of whichKis formed eccentrically, and on this portion the eccentricLis placed. To the clip ofLthe traverse rodPis coupled.Lis driven from the wheelGby means of a pin fastened inL, and engaging with a slot inG. Thus the rotation of the eccentricLis followed by the traverse of the guide bar.
(262) It will be noticed that the outer eccentricLis not only out of centre with the pinS, but also with the inner eccentricK. Thus the rotation of the latter perpetually establishes a new condition of eccentricity. At one point the throw of the combined eccentrics is smaller than at another, and there are fixed limits within which many positions are assumed. If the throw ofKis3⁄8inch, and ofL5⁄8inch, it is obvious that if they are both at the front centre their combined throw will be 1 inch. But ifKis at its back centre andLat its front one the combined throw is only 1\4 inch. Now owing to the fact that the wheelsGandHare made with one tooth more or less, it happens that 25 complete revolutions of the eccentrics are needed before they are brought with their centres coinciding after that position had been abandoned. The result is, that during every one of the 25 traverses a different throw occurs, and the length of the traverse is varied, as shown diagramatically in Fig.147. By altering the size of the wheelsG Hany number of variations desired can be obtained.
DIAGRAM SHOWING VARIATIONS OF TRAVERSEFig. 147.
DIAGRAM SHOWING VARIATIONS OF TRAVERSEFig. 147.
(263) Messrs. Howard and Bullough fit to their intermediate frame an electric stop motion. It should be explained that it is customary to pass two slubbings through the rollers at once, twisting them together to form one thread. If from any cause one of these ends breaks, the other may go on twisting, and a thin defective place would result. To obviate this, the arrangement named is applied. The slubbing bobbins are placed in a creel, and are passed between the surface of a metallic spring, and a roller placed at the back part of the machine. The drawing rollers are fixed in their usual position, and the spring is held by a bracket attached to one pole of an electro magnet and battery, the back roller being connected to the other pole. When the thread of slubbing breaks, contact between the spring and the roller occurs, and the circuit is closed. Thereupon a current is passed through the magnet, and one end of a lever is attracted so as to bring its other end in the path of a constantly rotating ratchet wheel. This arrests the motion of the latter, and so releases a catch on the stop rod, allowing it to be drawn along by the action of a helical spring. In this way the machine is rapidly stopped.
PRODUCTION OF SLUBBING AND ROVING FRAMES IN LBS. PER WORKING WEEK OF 56 HOURS.
HankRoving.Speed of Spindles.RevolutionsPer Minute.TwistperInch.Production.Maker’s Name.·50600·85114John Mason.·50600·85116Crighton and Sons.·50700·84115Howard and Bullough.1·007001·2056John Mason.1·007001·2056Crighton and Sons.1·007001·2059Howard and Bullough.3·0010002·0817John Mason.3·0010002·0816Crighton and Sons.3·0011002·0716·53Howard and Bullough.6·0014002·947·25John Mason.6·0013002·947·20Crighton and Sons.6·0011002·926·25Howard and Bullough.
John Mason.
Crighton and Sons.
Howard and Bullough.
John Mason.
Crighton and Sons.
Howard and Bullough.
John Mason.
Crighton and Sons.
Howard and Bullough.
John Mason.
Crighton and Sons.
Howard and Bullough.
Note.—The velocity of the spindles and amount of twist introduced will largely influence the productions as given above, which are only illustrative of the capacity of these machines.