The fibre is carried by the main cylinder down to the first worker e, which is the foremost to act after the cylinder has taken the jute from the feed-roller. The worker is abont 9 in. in diameter, and has a surface speed of 50 ft. a minute. Its carding-pins or points are inclined at a more acute angle than those of the main cylinder, and in a direction opposite to that of its revolution, which is the same as the contiguous surface of the main cylinder (Fig. 864). As a consequence, the fibres, being partially thrown off the surface of the main cylinder by centrifugal force, are caught upon the pins of the more slowly-revolving worker, the points of which are inclined for their recep tion, the worker e being adjusted so that its pin points shall be in. from those of the cylinder. The action of the main cylinder is therefore to pull the fibres upon the pins of the worker, and to carry them well towards their base, by which means, the latter roller auceeeds in retaining a great portion of that which has not been suffi ciently opened in the first stage of its passage through the machine. The worker, having thus secured possession of, and assisted to comb out more perfectly, the unopened fibre, is cleared in turn by the stripper f, a roller about 13 in. in diameter, and having its card-points inclined in the direction of its revolution (Fig. 864), and a surface speed of 450 ft. a minute, by which means, it is enabled to strip the worker e, whose cards are inclined to deliver them to its action. The latter in turn is similarly inclined to, and is stripped by, the main cylinder, revolving at a much quicker rate. The second worker and stripper perform a similar function, but they are adjusted a little closer than the above to the main cylinder, so that they will operate on any portion of the fibre that may have escaped the action of the preceding parts.
All the jute having been thus delivered again to the main cylinder, and, in its progress to this point, having been combed and carded until it is clean, and its fibres are laid parallel, it is carried along by the revolution of the cylinder, until the doffer his reached. This is a roller of about 16 in. in diameter, covered with rather finer cards than the preceding, and which are inclined away from the direction of its revolution. It is set still nearer than any of the preceding, its points almost touching those of the cylinder. This arrangement, combined with its relatively slow paco, enables it to strip all the oarded fibres from the oylinder, whence it is carried to the small pair of doffing-rollers k, which receive it in a thin sheet or fleece, and pass it into the conductor 4 which, from being the width of the rollers at the top, narrows until it is not more than 4 in. across. The fleece, in its transit along this way, is condensed into a sliver, and passes through the delivery rollers m, falling into the sliver-can n, when the work of the breaker-card is completed.
The surface speeds of the doffing-rollers k and delivery-rollers m are usually about 14 times the rate of the feed-roller b, hence, when the lap of jute is fed to the machine at about 2 lb. to 1 yd., it will be delivered at the opposite side in the sliver, attenuated 14 times = 7 yd. to 1 lb.
Jute being, like flax, capable of minute subdivision in its fibres, is usually submitted a second time to the process of carding. The machine used in this case is called the finisher-card, and, in its essentials, is exaotly similar to the breaker-card. The differences consist in the cards upon all the
rollers being finer than in the preceding case, and in each roller being set closer to its work. According to the comparatively rough or fine quality of work required, the pairs of working and stripping-rollers are less or more in number, varying from three to five pairs, the latter being employed when the best work is wanted.
Twelve cans containing the carded jute from the breaker-card are placed behind the finisher, and the sliver from each, laid upon the endless apron, forms a lap, which passes into the machine, and is further combed and subdivided to the required state. The irregularities which will obviously occur in the sliver from the breaker-card, are, by this means, almost eliminated ; and, as the speeds of the feed-roller and doffing-rollers are, in this case, 16 to 1, further attenuation takes place, the sliver delivered being of about 9i yd. a lb., and, as compared with that from the breaker, much more level. • Drawing.—The sliver from the finisher-card is next required to undergo further attenuation, and to have its fibres placed ill more perfectly parallel order. This is accomplished by the spiral gill drawing-frame, whose essential parts are shown in Figs. 865, 866, 867, 868. There are other kinds of these frames, but that illustrated is in most general use. Fig. 865 is a transverse section, showing the traveller-bars with the gills mounted upon them, Fig. 866 is a longitudinal section while the process is in operation. Fig. 867 gives an enlarged representation of the tra velling-bars and the gills or hackles, which are seen in section in the pre ceding Fig., 866. In Fig. 868, is illus trated an enlarged section of the tra velling-bar carriage.
In operation, the cans a, containing the slivers from the finisher-card, are placed behind the machine. The slivers are then passed over the guide-plate b, and conducted to the retaining-rollers c, passing under the first, over the second, and under the third. These con stitute the feed-rollers, their function being to supply the fibre to the gills d, upon the travelling. bars a, best seen in Figs. 867, 868. These bars are arranged just in front of the delivery side of the rollers, and each bar carries four " gills " or " hackles " —brass stocks filled with a row of vertical steel pins. On each side of the bars, are two shafts extending longitudinally across the ma chine, and one placed above the other. These have a large thread turned upon them in the middle portion of their length (f, Fig. 868), and are called the top and bottom screws. The top screws are cut at a pitch varying from 1 to 2 threads an inch. The ends of the travelling or gill-bars are bevilled, so as to fit into the angle formed by the thread of the screws, the body of the bars and the gills they are carrying being thus maintained in a vertical position. In working, by the revolution of the shafts, the bars are made to travel forward from the retaining-rollers, carrying with them the gills, whose pins, having penetrated the sliver, draw the jute along with them, their speed slightly exceeding that of the rollers delivering the sliver, which secures the latter being held tightly, so that it is prevented rising from the pins. The bars move upon steel slides, which keep them at an uniform elevation, and secure them in their proper position. The threaded part of the shafts is proportioned to the length of the fibre, being 10-11 in. for carded jute.