(144) Again referring to Fig. 69, it will be seen that below the dish =C= two blades or “mote knives” are placed, which can be readily adjusted so as to present a sharp edge to the cotton as it is flung down by the licker-in, and so scrape off the “motes” from its surface. The object of these knives is similar to that of the leaf extractor used in a scutcher, and described in paragraph 77. Beneath the licker-in and beyond the knives a casing =E= is placed. These are usually made of tinned iron, and form a sort of grid through the interstices of which the droppings can fall. From their position they are known as “under casings.” The exact setting of these is a matter of high importance during working, and should be ascertained by observation when dealing with different classes of cotton. It has been found that the use of under casings with the licker-in has been attended with considerable economy. They are also used beneath the cylinder, and should be as carefully set as is the case with those under the licker-in. In determining the distance, regard should be had to the quality of cotton used and its length of staple, as, if the fibres actually strike the bars of the grid, they may adhere to them and partially choke the latter. On the other hand it is found that too wide a setting is followed by increased waste. It is both possible and advisable to find the golden mean by observation. Messrs. Platt Brothers and Co., Limited, have a special way of forming the undercasings, the bars of which are secured to turned wrought iron segmental rings, the position of which can be regulated from outside the machine by special setting screws. They also attach the licker-in casing and mote knives to the cylinder under casing, so that they are all set in combination, and an alteration of the position of the licker-in leads to a readjustment of all its attachments. The three gauges mentioned in paragraph 132 are combined, and the casings set sufficiently far from the cylinder to permit of the introduction of the three gauges. That is to say, the space left is ·031 of an inch, which is found to be generally ample, but this is subject to the remarks previously made.
(145) In addition to the necessity for under casings, covers are required for the licker-in, cylinder, and doffer. As the circles described by the teeth on these three parts approach each other, as shown in Fig. 46, it is desirable that the covers used should go as near to the point of approach as possible. If any space is left the fly and dirt speedily fills it, and from time to time drops upon the doffer, causing a thick place in the sliver. The arrangement used by Messrs. Dobson and Barlow is shown in Fig. 72, and it will be seen that the cover goes close down into the space left between the cylinder and doffer, and effectually prevents any accumulation of dirt. The cover is in three parts, and is hinged so as to permit of the surface of either cylinder =H= or doffer =F= being stripped or ground as desired. Setting arrangements are provided, by which the cover can be maintained in an accurate position during the whole period of work, although it may be necessary to set the doffer in towards the cylinder. The shape of the centre portion is specially designed to permit it to receive the strippings from the flats. Again referring to Fig. 69, it will be seen that similar arrangements are made for the licker-in and flats, the space between the flats and the cylinder wire being filled as shown, as is also the space between the licker-in and cylinder. The cover =F= over the cylinder and licker-in can be set up as desired, as can also the filling piece =L= below. All the covers are arranged to fit closely to the bend at the edges, so that there cannot be any blowing out at the side of the cylinder.