Fig. 65.J.N.
(130) In Fig. [65] is given a side elevation of one side of a carding engine, in which the bend is made in an entirely different manner to any previously described. This is really a revival of a plan which was suggested many years ago by James Smith, of Deanston, but which was dropped on account of certain difficulties in adjustment which are now overcome. The machine as illustrated is made by Mr. Samuel Brooks, and is nearly the latest form put on the market. The pedestal A has a circular flange formed on it about midway of its length, to which a bush C can be bolted by the three bolts M. The bush is placed over the inner boss of the pedestal, and can be set in its proper position, which may be ascertained at any time by the pin J, passing through a hole in the pedestal flange and one in the bush when the latter is quite concentric with the cylinder, and only then. On this bush a wheel D, with a flat periphery, is fitted and revolves. The periphery E of this wheel sustains the flats F, the traverse of which cause it to rotate at precisely the same circumferential speed as that of the flats. The friction of the flat ends is in this way avoided, which is claimed as one of the important features of the new arrangement. When the machine is new the diameter of the wheel D is of the exact size needed to sustain the flats, and keep the wire points the requisite distance apart, theoretically, 1⁄1000th inch. But when the wire has worn and has been re-ground, it is, of course, necessary to reset the flats. This is effected by means of the milling cutters G, placed as shown, which can be set in by the arrangement shown in side elevation in Fig. [66], and in partial section in Fig. [67]. The cutter G is fixed on a shaft borne by the bracket F, which is attached to the bend, and is moved inwards in a radial line by the screw H, the latter being arranged on the micrometer principle. The screw is threaded 25 to the inch, and the worm wheel I has 20 teeth. The rotation of the latter one tooth implies a corresponding movement of the cutter G 1⁄500th inch. By subdividing the disc K on the spindle carrying the worm L, as much as desired, the cutters can be moved in or out to a very slight but ascertainable degree. A similar arrangement is fitted to the bush C, by which when unlocked it can be lowered as desired.
Figs. 66 and 67.J.N.
(131) In setting, or, rather, in lowering the flats—because that is practically all that can be done by this arrangement—the bush is unlocked and the pin J taken out. It, with the wheel, is then lowered until the wires on the central flat and those on the cylinder can be heard to click. A careful note is taken of the amount which the bush has been lowered, and it is again raised to its central position and locked. Suppose that the amount was 1⁄250th inch—a very extreme supposition—then the distance the flats have to be lowered is that distance less 1⁄1000th inch, the standard distance between the wire teeth, or 3⁄1000th inch. The disc K is therefore revolved 11⁄2 times, which moves the cutters G inward to that extent, and, in consequence, the diameter of the wheel D is reduced, so as to provide a course for the flats of the exact size required. The cutters G are driven by a band from the cylinder shaft, and the wheels C are traversed as usual during the process of reduction. This arrangement is a novel one, but it is clear that, if successfully carried out, it provides a perfectly concentric flat course.
(132) Before proceeding further, and dealing with another form of machine, a few words may be said on the subject of setting the flats. It has been shown that in many cases a delicate indicator and micrometer screw is fitted, by which it is claimed the most exact settings can be made. There can be no dispute as to the power to do this which is thus provided, the only question is whether the circumstances of the case call for it, and whether in actual work any such accuracy is obtained and maintained. There are four points where adjustment is required in a carding engine. These are between the dish feed plate and licker-in; between the licker-in and cylinder; between the cylinder and flats or rollers; and between the doffer and cylinder. Messrs. Platt supply three gauges, respectively ·013, ·011, ·007 of an inch thick. The finest of these it will be seen is 7⁄1000ths of an inch thick, so that in this case at least the theory as to setting to 1⁄1000th is disregarded. In adjusting the flats, by far the commonest plan is to do so during the time the mill is standing, when everything is quiet. The bend is then dropped until the gauge which it is intended to use can be pushed between the two sets of teeth. If it is afterwards desired to get very fine setting, the bend is lowered until the slow revolution of the cylinder produces a “click,” which shows that the teeth of the cylinder and flats are in contact. A little elevation is given to the bend so as to leave a space between the teeth. A skilful setter can tell at any time by the “touch” of the teeth if they are too closely set, but the vibration existing during working hours may disturb his observation. When an indicator is used the practice is to establish the clicking point, and then turn back the screw until the flats are raised the desired distance.
(133) It is questionable whether it is possible to maintain so accurate a setting during actual work over a long period after wear has begun. It is hardly likely that many machines continue to work with this close setting. The practice is rather the other way. Wider spaces than ·011 are common, and it is unreasonable to expect anything else. The function of the wires on the cylinder being to seize by means of their points the fibres of cotton and bring them under the influence of the flats, it is obvious that the question of efficient carding turns very largely upon the charge of cotton in the wire. If light carding is taking place—that is, if little cotton is passing over the cylinder during a fixed time—the delicate setting is both possible and desirable, as it would result in the cotton fibres being thoroughly combed from end to end. But if the cotton is fed rapidly, so that the cylinder becomes highly charged and its surface covered with a comparatively thick fleece, a too close setting would result in considerable damage to the fibre. As the prevailing practice is generally based upon commercial considerations, the last is the more usual condition existing, and extremely close setting is in this case both impracticable and undesirable.
(134) Even if this extra fine setting named were adopted there is nothing to show that it cannot be attained with the flexible bend. True, the setting of the latter involves a little more labour, but is it quite demonstrated that it is not necessary labour? The construction of flexible bends is now such, as has been shown, that their flexure, 3⁄8ths of an inch, is made with absolute ease and accuracy by means of the setting screws. There is an old adage that “the proof of the pudding is in the eating,” and no candid person will contend that carding engines made with flexible bends of the Leigh type produce either worse slivers or make more waste than others. On the other hand, it is only fair to say that the converse of this proposition holds true, and that good slivers are obtained from machines made with indicators and special setting appliances without more waste being made than in the case of flexible bend machines. It is, however, more than probable that the system of setting by the ear is adopted in every case of successful carding.