Fig. 104.
Fig. 104.
Fig. 105.J.N.
Fig. 105.J.N.
(180) In Fig.105an illustration is given of an arrangement patented by Messrs. Knowles and Tatham. The grinding bracket carries a pivot on which the weighted leverFoscillates. The unweighted end ofFpresses against the top side of the flats as they are successively brought within the sphere of its influence, being of course turned upside down at this point. A plateBis fixed in the position indicated, being of sufficient width to engage with the flat end without touching the wire.Bis, as shown, formed with a shoulder, the difference in the height of the two planed surfaces,DandE, thus obtained being equal to theheel of the flat. The grinding roller is indicated by the dotted line, as is also the bearing. The position of the shoulder onBis such that the whole of the wire has been ground before the flat end passes over the shoulder, and the flat is thus kept approximately in correct position for maintaining the parallel relation of the wire and working faces. Before the wire on the succeeding flat begins to be ground, one of the ridges on it passes on to the lower surfaceE, so that the wire face is brought into a horizontal position.
Fig. 106.J.N.
Fig. 106.J.N.
(181) In Fig.106an arrangement made by Messrs. John Hetherington and Sons is illustrated. The ordinary grinding bracket is replaced by another one, fixed in the same position, which carries at its upper end a slideK. This moves in a bed prepared for it in the bracket, and has the necessary bearings formed for the rollerM. Attached to the slideKand the bracket is a spiral springT, which always tends to drawKagainst a stop. The vertical leverLextends upward, and its upper end presses against the inner side of the horn of the slideK, so that whenLis oscillated the slide is moved forward. On the same spindle, forming a centre forL, a leverQis fixed, which has a vertical tail-pieceP. A rib is formed onLthrough which a screw is threaded, the point of which presses against the edge of the tailP, and is, when adjusted, locked by means of a nut. The flats pass beneath a plane surface fixed to the inside of the grinding bracket, and their working faces are pressed against it by means of the weighted leverP. The line of the flat traverse while so pressed is shown by the dotted lineU V. When a flat enters upon the surface on the bracket it is pressed upwards, as described, and, while so held, the grinding bracket is moved forward over the teeth by the action of the camRfixed on the chain roller shaft. The rotation ofRdepresses the leverQ, and gives the required movement to the leverLand to the slideK. It will be noticed that the slideKis placed at such an angle that it traverses to meet the flat, the object of this being to establish such a line of motion of the grinding roller as corresponds to the inclination of the flat relatively to the cylinder during work. The roller traverses in the opposite direction to that in which the flat moves for a certain distance, when it returns and again passes over the wire surface as that is moving forward. During the reverse movement it moves vertically to the same extent as previously made, so that in both cases it grinds the wire points in the desired plane, and thus maintains the true relative distance of both sets of teeth. By the time the reverse movement has taken place, the flat being ground has moved forward sufficiently to pass beyond the range of the roller, and the latter is then ready to grind the next of the series. In this device the principle of grinding by the movement through an angular plane of the roller axis is the central idea, and there can be no question that this is a very likely method of getting a true result. For it is obvious that if the flats were held stationary, and the roller traversed in an inclined plane, the necessary regularity would be given to the wire surface with great exactitude. A similar result is obtainable by similar means although the flats may be slowly moving, and this is demonstrated by the motion just described, which has been used with great success.
(182) In Fig.107is shown a side elevation of Edge’s grinding apparatus, which is made by Mr. Samuel Brooks. Its essential feature consists of a curved plateB, which is fixed either to the grinding bracketA, or to a fixing attached to it. Over this the flatsCtraverse, and when they reach the centre the snugs at the back are drawn upon the raised portionB1, which is sufficiently long to permit of each flat being in contact with it the whole of the time it is passing under the grinding roller. A plateDis maintained in a position above the flats, and the method of forming it and regulating its position constitutes one of the chief features of this arrangement. The grinding rollerGis sustained by a bracket or bearing, in which its axisFrotates. The bracket rests upon a cylindrical stemE1, fitting inside a cup, and also in a similar recess or barrelE. The latter has a long boss which forms part of, or is attached to, the plateD, andE1is screwed and fitted with two cylindrical nuts. Thus, by adjusting the nuts, the distance of the centre ofFfrom the under surface ofDcan be varied at will, and the pressure of the grinding roller upon the wires fixed. The action of this mechanism is as follows: As the flatsCtraverse they ride upon the projectionB1, and their working surfaces are forced against the under side of the plateD. The latter is shaped so that the traverse of the flat causes one side of it to become depressed and the other to be elevated. The peculiarity of this arrangement lies in the fact that the change of position of the plane of the flat faces issufficient to ensure all the wire points being presented to the action of the grinding roller in their correct plane. In other words, the effect is nearly identical with that obtained when flats are held separately in a stationary frame, and the grinding roller passed over them. Not less important is the ease with which the position of the setting plateDcan be adjusted relatively to that of the grinding roller. This power of adjustment is the chief feature of this mechanism, and as, when it is once made it is constantly maintained, each of the series of flats will be so ground that the distance of its wire points from its working face will be identical with that of each of its fellows. Thus a set of thoroughly good flats is obtained, each of which is in the best condition to do its work. A further point which it will, perhaps, be well to mention is, that the power of adjustment, existing by reason of the two nuts shown, permits of the flat ends being subject to the required pressure during grinding, which is afterwards constantly maintained.
Fig. 107.J.N.
Fig. 107.J.N.
Fig. 108.J.N.
Fig. 108.J.N.
(183) Fig.108represents in partial section Higginson and Mc.Connell’s patent, which has been adopted by Messrs. Dobson and Barlow. It consists of a bracketAfixed as usual to the machine framing, and having at its upper portionCa slot in which the small slideDis fitted. This slide has its underside shaped to the extent necessary to give the flats the required amount of inclination during grinding, and at the end of this surface is formed with a lip as shown. A spiral springEis fitted in the slot, and pressesagainst the end of the slide when the latter is in its normal position. The flatsG, of which there are only two shown, travel in the direction of the arrow, and when turned face up the chain lugs mount upon the nose of the short leverH. A bell-cranked leverFis fixed on the same shaft asH, its vertical limb having a set screwIfitted, by which its range of movement is limited, while its horizontal arm carries a balance weight. As the flats traverse they alternately mount upon the higher part ofH, and are thus pressed into contact with the inclined part of the slideD. Immediately afterwards the flat comes in contact with the lip, which prevents its further forward movement. At this time it is in such a position that the wire surface is horizontal, and while in that position it is passed under the grinding rollerB. As it traverses it carries the slideDalong with it, gradually compressing the springEuntil the wire has been entirely ground. When this has happened the slide makes a little further forward movement—its entire traverse being shown by the two vertical dotted lines—when the chain lugs pass off the nose ofH, and the flat falls clear of the slideD. Immediately this occurs the springEpushes the slide back, and it is ready to receive another flat. The chief feature of this motion is the employment of the sliding wedge. When the flat is pressed on to this it is held as though it was on a stationary bed, and is, by reason of the horizontal position of the slot, maintained in a constant plane. Thus the wire surface is presented to the action of the roller in a plane parallel to that of the slot, so that, whatever the variation in the flat end caused by wear, it is not affected. There is another point which is somewhat important. The tension upon the chain links caused by the friction of the flats upon the bend is very considerable, and results in a gradual lengthening of the pitch of the chain. If, in addition to this, the extra friction set up by the pressure of the leverHon the flat, thus causing the latter to be forced against the surface of a plate, be taken into account, this tendency to lengthen will be increased. The extent to which this is to be considered varies naturally with the pressure exerted. Although it is not perhaps great it is appreciable, and it is a matter to be considered. In Higginson and Mc.Connell’s motion this friction is slight, as the slideDis arranged to move without much power, although thecompression of the spring towards the end increases the amount required. As the wedge springs back into position it has to slide over the face of the next of the series of flats, which by this time has passed upon the end of the leverH. Thus, although the flat travels forward without friction, there is a certain amount to be considered as the wedge is passing into position on each flat, the pressure being then exerted as in the case of a fixed plate until the flat presses against the lip, and the wedge begins again to slide.
Fig. 109.J.N.
Fig. 109.J.N.
(184) In Fig.109a side elevation of an arrangement made by Messrs. Platt Brothers and Company, Limited, is shown. In this case, also, the device of a sliding angular surface is employed. A slideH, which is guided in the upper part of the grinding bracket, and upon which a pull is constantly exercised by the balance weightMand chain shown, has affixed to its lower side the angular or inclined surface against which the flat end is pressed during grinding. As in the mechanism just described, the surface to receive the flat is formed with a lip, so that the forward traverse of the flats causes it and the slideHtomove in the direction of the arrow. A slight curve corresponding to that of the bend is given to the sustaining surface of the slide, and the flat is thus held in a corresponding position to its working position. On the axle of the chain wheel by which the flat chain is driven is a toothed cam plateK, which is shaped as shown, so that it can give a forward movement to the leverL. The latter has fixed in it a tooth or catch, which constantly presses on the surface of the wheelK. The lever or barLis formed with a slot at one end, with which a pin fixed in the end of the chain wheel axis engages, so that the lever can freely slide upon it. The other end of the lever is jointed to a leverB, fixed upon a short shaft on which is also fastened the short leverFand the curved armD. There is a similar arrangement of mechanism at either side of the machine, and the two armsDare coupled by means of a round barE, which acts as a weight. In this way a certain torsion is put upon the short shaft, and a tendency is set up in the leverFto move upwards. In doing soFpresses against the slideGplaced inside the framing and bend. The upper end ofGwhen pushed up presses against the back of the flat and forces it against the inclined surface, where it remains until the flat is ground.
(185) The action of the mechanism is as follows: When a flat has passed under the grinding roller completely the rotation of the wheelKcauses one of the teeth to push the leverLforward, and so oscillate the shaft upon which the leverBis fastened. This raises the armD, and relieves the slideGof the pressure exerted by the weightE. The flatIat once falls out of contact with the surface of the slideHwhich is thus free to fall back into position to receive the next of the series, this being the position shown in Fig.109. It is essential to notice that, while the backward movement of the slideHis taking place it is out of contact with the flat, so that, neither during its forward or backward traverse is there any extra tension put on the chain. Immediately the slide has completed its movement the engagement of the catch inLwith the tooth inKceases, andLis free to slide inwards, which it is caused to do by means of the weightE. At the same time the slideGis pushed upwards, and lifts the next flat into contact with the inclined surface onH. It only requires to be said further that the pitch of the teeth onKensures the requisite movements being given toGto cause the latter to engage every flat in its turn.
(186) The rollers and clearers are ground after removal from their places in the machine. A machine of which Fig.110is a perspective view is employed for this purpose, this being the type made by Messrs. Dronsfield Brothers, who have specially devoted themselves to this class of machines. The machine consists of a frame which has bearings formed, in which the shaft of the grinding roller revolves. Affixed to the lower portion of the frame is a counter shaft from pulleys, on which the emery roller is driven at a speed of 300 revolutions per minute. The roller to be ground is borne by the two bearings shown, which are slid laterally by the extremities of arms secured to a transverse spindle sustained by brackets fixed to the framing. The two arms are moved to or from the frame by means of a hand wheel which is keyed on a short spindle, on which is also fixed a worm. This engages with a quadrant fastened on the transverse spindle, so that the rotation of the worm in either direction gives a movement to or from the grinding roller. In this way the card roller is brought into contact with the grinding roller equally over its whole surface, the axis of thebearings in the arms being always parallel with those of the grinding roller. A bonnet is placed above the machine, and the dust is removed by the small centrifugal fan shown. The card roller is driven by a separate strap from the counter shaft.
(187) The flats of self-stripping machines are removed from the latter, and are secured on suitable bearings formed on the frames of a special grinding machine. The bearings are adjustable, so that the correct position is given to the flat during grinding. The faces of the flats when so held are moved across the grinding roller, which revolves at a high speed. As the arrangement is a very simple one, and does not present any great novelty, it is not necessary to describe it in great detail.
Fig. 110.
Fig. 110.
(188) As the wire clothing on the cylinder, doffer, rollers, and flats becomes filled with motes, neps, and short fibres, it is necessary to remove these periodically. This operation is called “stripping,” and it is a very important one. Whatever may be said to the contrary, stripping cannot be dispensed with unless some specific be found for the removal of the impurities as fast as they are taken out of the cotton. The plan formerly adopted for this purpose has fallen into disuse, as it implied the stripping of the card during work, and led to the mixing of the stripping with the finished sliver. It has been shown that a clean wire surface is the best for carding, and it will be easily seen that the filling of the spaces between the teeth will materially reduce the elasticity of the wires. Regular stripping is for this reason advisable; but the ease with which, if so carried out, the dirt can be removed, constitutes a further reason for this procedure. Carding speedily becomes poor in quality unless this is looked to, and all spinners should carefully watch this point. Another matter is, that inasmuch as it is practically impossible to strip all the cards simultaneously,the operation should be effected so that there should be an equal proportion of clean and dirty or half dirty machines. These are all little points, but they are of great importance in the effective working of a machine.
Fig. 111.
Fig. 111.
(189) The stripping of cylinders and doffers was usually carried out by a wire hand brush, the teeth of which are thrust into the wire spaces and then drawn downwards, so removing the “strips.” This is now entirely superseded by the revolving wire brush, such as is shown in Fig.111, as made by Messrs. John Whiteley and Sons. This is a roller on which is wound card clothing made of hardened and tempered wire. It can be revolved by hand or power, and is carried in the grinding brackets. In stripping it should be set so that the teeth finally penetrate about1⁄16th inch into those on the cylinder, but should be gradually set in to that depth so as to avoid damaging the wire. A speed of 200 revolutions for hardened and tempered, and 150 for mild steel cards is recommended by the makers, the cylinder revolving slowly in the meanwhile. The fleece of strippings thus produced is removed from the roller by dividing it along the narrow uncovered space shown, after which it will lift off by slowly revolving the roller. A similar plan is followed with the doffer. The rollers and clearers are usually stripped by hand, and it is hardly possible to adopt a better plan.
(190) In closing the consideration of the carding engine and its accessories, it is necessary to enforce upon the reader the dictum that good carding is absolutely essential to good work. With it a good even yarn can be made. Without it no such result need be looked for. It is impossible to lay too much stress upon this point, and the care bestowed upon the machine and its clothing will amply repay the spinner. Cleanliness is essential, and it is certain that the want of it often leads to trouble and loss in the subsequent stages of spinning.