(109) The sliver is loosely gathered together into a strand by means of a specially shaped plate, and passed through a pair of calender rollers =H= Fig. 44 by which it is partially compressed. A slight traverse is sometimes given to the trumpet-shaped tube through which the sliver is taken to the calender rollers. After leaving the latter the sliver is taken upwards to an opening in the plate at the upper part of the frame =I=. This frame forms part of the apparatus known as the “coiler,” which is illustrated in vertical section in Fig. 45.
(110) The coiler consists of a frame =I= within which is a vertical shaft =V= driven by means of the short horizontal shaft from the calender rollers. At the upper end of the shaft a second pair of bevelled wheels are geared, which drive the calender or feed rollers placed immediately below the trumpet-shaped orifice in the cover =T=, which is hinged as shown. One of the rollers is supposed to be removed in order to show the arrangement more clearly. The sliver entering by the orifice in =T= and, passing the rollers, is delivered into a short tube =X= forming part of the plate =Z=. The latter is driven in the direction shown by the arrows by means of the spur wheel =Y= gearing with a rack formed on the edge of the coiler plate =Z=. The sliver is thus given a slight twist, and is delivered into the can =W=, placed on a plate free to revolve and borne in the lower part of the coiler frame. The can is placed eccentrically to the coiler plate =Z=, and is slowly revolved in the opposite direction to it, as indicated by the arrows. In this way the sliver is laid within the can in coils, which are peculiarly disposed so that they do not become entangled. Often, within the can, a pair of discs, coupled by a coarsely pitched helical spring, are placed, upon which the cotton is received. The object of this device is to relieve the strain upon the sliver, which would otherwise arise if it were unsupported as far as the bottom of the can. As the weight comes upon the upper disc the spring compresses.
(111) The parts thus described are common to all cotton carding machines, and would remove the major portion of the motes and heavier impurities, but only a partial parallelisation of the fibres would occur; nor would more than a small portion of the short, broken, or immature fibres or “neps” be removed. It therefore becomes necessary to devise a means by which, while the cotton is on the cylinder, it may be treated so that the completion of the cleansing and the arrangement of the fibres are carried out. In order to do this the fibres must be submitted to a combing process, by which, while held by the cylinder teeth, another set of teeth act upon them. The form of carding engine which first found extensive employment, and which is yet preferred by many spinners, is known as the “roller and clearer card.” This machine is illustrated in Fig. 47, as made by Mr. John Mason, in perspective, and in Fig. 46 diagrammatically. After the cotton has been taken from the licker-in =B= by the cylinder =E= it is carried past a roller =J=, known as a dirt roller. The diameter of this is from 5in. to 6in., and it revolves at about eight revolutions a minute. When the fibres are taken up by the cylinder wire, they are partially embedded in the interstices of the clothing, but the motes remain on the surface, from which they are easily removed. The dirt roller =J= takes these up, and, being covered with a coarser pitched wire than =E=, the motes become fixed in the former, from which they can be stripped. This can be effected by a hand comb at regular intervals, or by an oscillating comb suitably operated in the way made by Messrs. John Hetherington and Sons, as illustrated in Fig. 48 (page 60). In this case the dirt roller =A= is driven by a side shaft by means of the worms =B= and =D=, the latter gearing into the wheel =E=, which is keyed on the dirt roller spindle. A cam =F= fixed on the first working roller gives a reciprocating motion to the rail =G= by which the comb =H= is operated, the roller =J= being thus stripped. An iron tray =I= is fixed, as shown, into which the strippings fall.