(344) The whole of the points relating to winding having been considered, the motions used in the fifth and last period require describing. When the carriage is near the completion of its inward run, the various parts are in the following position: The strap is on the loose pulley and the backing-off side shaft is being revolved either by the gearing named, or by its independent band; the back shaft clutch is disengaged and the back shaft is revolving so as to aid in drawing up the carriage; the rollers are disengaged and are not delivering roving; the taking-in friction is engaged, and the scroll bands are drawing in the carriage; the quadrant arm is completing its forward movement, and the spindles are revolving in their normal direction; the winding faller is locked and the wire is approaching the nose of the cop; and the counter faller is in contact with and sustaining the threads. As soon as the carriage arrives at the roller beam, the whole of these motions require changing, so that the different parts shall occupy the positions indicated in paragraph 286.
(345) This operation is mainly the work of the cam shaft, but in part is performed by other mechanism. As soon as the carriage arrives at, or near, the end of its outward run, the horn S1 on the carriage comes in contact with the anti-friction bowl R1 in the long lever T and depresses it (see Fig. [156]). This removes the nose of the releasing lever from the raised surface on V and allows the friction clutch W X to come into gear. The cam shaft immediately begins to rotate, and the three cams to act upon the various parts in the reverse way to that previously described. The rotation of the cam Z (Fig. [156]) performs the two functions of disengaging the taking-in friction clutch and engaging the back shaft clutch, the motions of these always being closely related. The cam W during the same period allows the roller clutch to go into gear, and the delivery of roving again begins. The rotation of the cam Y causes it to exercise a thrust on the pin fixed in G (Fig. [158]), so forcing the driving strap over on to the fast pulley, this giving renewed motion to the spindles. The same movement causes the lever H to be pushed forward until the shoulder formed in it can again engage with the fixed catch L, the spring P pulling the end of H upwards as soon as it is sufficiently far forward. The strap guider is thus again locked when the strap is on the fast pulley. By the time these engagements and disengagements have been made, the cam shaft M has made its second half revolution, and the end of the release lever again presses upon the raised surface on the cam V and detaches the friction cone W from X. The cam shaft is thus stopped and remains stationary until the end of the outward run as described in paragraph 291.
(346) The whole of the parts governed by the cam shaft having thus resumed their original position, it remains to be shown how the winding and counter fallers are released, so as to be able to assume their relative positions out of contact with the yarn. The unlocking of the winding faller must be made as late as possible in the inward run, but the exact period at which it is made is affected by the height of the cop nose on the spindle. The termination of winding requires to be made throughout the whole period of building a set of cops, at such a point as to leave sufficient yarn to coil on the spindles between their points and the cop nose. It will be easily seen that this quantity is varying throughout the whole of the formation of the cop, and that the length to be wound on is greatest at the commencement of the cop. This implies the unlocking of the winding faller at a point which is made gradually later, and this is well carried out in the Platt mule. At the lower end of the locking lever is a curved arm or “boot leg,” which, at the termination of the inward run, comes in contact with the fixed stop bracket G (Fig. [161]). The face of this is so shaped that the moment of unlocking is regulated in accordance with the requirements of the case throughout the whole of the formation of the cop. This is an important point, and requires careful attention. In a special form of mule, made by Messrs. Platt Brothers and Co., for finer counts, the stop bracket is a movable one, and is released by the run of the carriage, so as to slide forward and unlock at the exact moment required. The finer the yarns the more care is required in this respect, owing to their greater liability to breakage.
(347) Referring now to the release of the winding and counter fallers, it is essential that they should leave the yarn free as soon as spinning begins. For this purpose the lever J is raised by contact with the small roller W (Fig. [159]), and its weight is removed from the counter faller shaft, and also from the winding faller. Still further to facilitate the descent of the counter faller, which is sometimes a little sluggish, a stop is placed in the headstock, which engages with a tail piece on the counter faller shaft when the carriage has run in. This arrangement is shown in the dotted lines at the right hand top corner of Fig. [161]. The weight of the winding faller connections is, of course, sufficient to lift it quickly out of contact with the yarn.
(348) The operations thus described constitute the fifth period, and at its termination the mechanism is again engaged in the work of spinning or twisting, being at the commencement of another cycle of movements. There is, however, one more piece of mechanism to refer to before the description of this machine can be brought to a close. It was seen that during the period of winding the chain was drawn off the winding scroll during the forward stroke of the quadrant arm. Referring to Fig. [172], which represents a portion of the mechanism relating to the quadrant, it will be seen by the arrows that during the outward run of the carriage, the quadrant M also makes its backward stroke. During the same period it is necessary to rewind on the winding scroll the chain C which was previously unwound, and this is effected by the cord S. S is attached at one end to a hook or staple T, fixed to the framing, and at its other end to a weighted lever U, pivoted on a bracket fixed to the floor. The cord S, in its course, passes over the two pulleys shown fixed to the carriage, and its tension is sufficient to cause the pulley on the shaft X to be rotated by the inward run of the carriage, thus winding the chain C on to the scroll. By the termination of the outward run this operation is concluded, and the chain is ready to act again efficiently as soon as winding recommences. When a “set” of cops—that is, the whole number spun on a mule—is finished, it is “doffed” or stripped from the spindles. As soon as this is completed the winding nut is wound back by hand to the bottom of the quadrant, and the copping plates are also restored manually to their original position.
(349) The description thus given of the machine as made by Messrs. Platt will enable an accurate idea to be obtained of the mechanical movements which are found in the work of a mule. It is true that this special machine differs in some of its details from many of other makers, and that there are motions fitted to it which are not found in other machines. When the latter are used, however, they tend to increase the automaticity of the machine. The winding chain shortening, or, as it is more correctly called, the nosing motion, and the backing-off chain tightening motion, are of this class, both tending to an increased efficiency. The main principles in a machine of this class are embodied in the mule described, and the general explanations given will prove serviceable, whatever may be the make of mule studied.
Fig. 173.J.N.
(350) One of the important points of difference between this and mules of other makes is found in the position of the cam shaft. This, it was seen, is in the Platt machine placed above the axis of the rim shaft. In other cases it is placed, as shown diagramatically in Fig. [173], along the headstock of the mule, and below the centre of the long or “balanced” lever T. In this case the cam shaft K is a tubular one, and has passed through its centre the shaft M, which is suitably driven from one end. The cam shaft is fitted with a friction clutch at P, the fixed half being on the tubular shaft. The other half slides on the shaft M, being pressed up to the fixed half by the spiral spring shown. On the long lever T at the point L a pendant cam plate is hung, which surrounds the cam shaft as shown in a detached front view and section in Figs. [174] and [175], and is formed with a slot so as to permit it to rise and fall freely. The cam plate has two raised cam surfaces or courses, against which the end of a pin is pressed by the action of the spiral spring. The pin passes through the half clutch fixed on the cam shaft, and presses against the sliding half on the shaft M. Thus when the pin is on the raised part of the cam plate the clutch is detached, while if it is on the lower part the clutch is in gear. When, therefore, the inner end of the balanced lever T is depressed, the fall of the pendant plate causes the pin to come upon the lower part of the cam course, and permits the engagement of the clutch. The cam shaft thus makes a half circle turn, and effects the necessary changes for beginning spinning. This causes the end of the pin to run on to the second cam course, and by the time the half revolution is made, it comes on the raised surface and disengages the cam. In this position it rests until the outer end of the long lever is depressed, when a similar action occurs, terminating in a similar way.