Modern Cotton Spinning Machinery, Its Principles and Construction

by Joseph Nasmith

(142) The defect of the Wellman machine in modern eyes is principally its slow velocity. The great weights which are now obtained from revolving flat cards cannot, or at any rate have not, been obtained from the self-stripper, and, in consequence, the latter has become discredited. But it must not be forgotten that the former machine has had an amount of mechanical skill lavished upon it which has been absent from the latter. This does not mean that the Wellman has not been well made, but it has not been so well constructed as the revolving flat type has during recent years. It is quite within the bounds of possibility that the self-stripper may have a revival, when its undoubted capability for good work may be combined with great productive power. It is often combined with a roller machine and used as a finisher carding engine, and is in other cases fitted with two or three rollers before the flats are reached.

(143) Reference was made in paragraph 105 to the use of a dish-feed. In Fig. [69] illustrations are given of this part of the mechanism, as made by Messrs. Dobson and Barlow, this being a reproduction of an illustration contained in a pamphlet on “Carding,” by Mr. B. A. Dobson. It will be seen that the feed-roller A revolves in the curved portion of the plate C, and that the nose of the latter is specially shaped to suit various classes of cotton. The principle involved here is precisely that referred to in paragraph 94 in dealing with the scutcher feed. The shorter the staple the more acute the surface from which it is struck can be without damaging the fibre. While a long fibre will permit of bending round a roller or lever end of large size, the shorter stapled varieties will simply be dragged downwards and crushed with precisely the same treatment. A close examination of the three views marked K, G, and R will illustrate this point, these being respectively for Surat, American, and Egyptian cotton. The adoption of the dish-feed is one of the most important of the minor improvements made in the carding engine, and leads to the straightening out of the lap end, owing to the exactitude of the rate of feed which can be attained. For the full success of this appliance it must be used in conjunction with the saw tooth on the licker-in, a description of which is given in the next chapter. This is a description of tooth which does not become charged or choked with dirt, nor does it require grinding, so that it is always in condition to deal effectually with the cotton. The action of this class of tooth is very graphically shown in Figs. [70] and [71], two reproductions of photographs in Mr. Dobson’s paper above referred to, of a lap end before and after the licker-in has acted upon it. They very clearly demonstrate the enormous effect produced by the licker-in teeth, and show how effectually all dirt and motes are removed.

(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.

Fig. 69.J.N.

(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.

Fig. 72.J.N.

(146) The driving of the cylinder is obtained from the line shaft by means of a fast pulley fixed on the cylinder shaft, a loose pulley adjoining it to facilitate stoppage. The licker-in is usually driven from the cylinder by a crossed strap, and the doffer from the licker-in by a similar strap, which passes over a pulley mounted on a stud fixed in a lever. The pulley has a pinion on its boss, which engages with the doffer wheel U, and so drives it. The pinion, or “barrow-wheel,” can thus be easily thrown out of gear, as desired. The feed-roller is driven by a side shaft from the doffer shaft, placed on the other side of the machine to the main driving and the doffer comb by a cord passing over a grooved pulley on the cylinder shaft. The calender rollers are driven from the doffer, and the coiler shaft from the spindle of the calender roller.

(147) The pedestal is constructed with an extra long bearing, the shaft being 3¹⁄₂ inches diameter and the bearing 7 inches long. The bush lining the pedestal is usually made of phosphor bronze, or some equally good material, in order to resist wear. It was pointed out in paragraph 119 that it is essential that the position of the centre of the cylinder shall be continually maintained, and it is therefore desirable to guard against its movement. If it is considered, it will be understood that the centrifugal action set up by the rotation of so heavy a body as a carding engine cylinder will cause it to endeavour to roll forward, and thus induce wear in the front of the cylinder bearing. This is aided by the pull of the strap, which is usually towards the front. The provision of some ready means by which the wear can be taken up and the position of the cylinder centre restored, is, therefore, of great service. It is not practicable to employ the conical bearings often used in other classes of machines, as the wear not being equal, a tightening of the bearing would not take it up.