Fig. 119.
Figs. 121 and 122.J.N.
(202) In Fig. [119] a perspective view, and in Fig. [120] a sectional view is given of Messrs. Dobson and Barlow’s Heilmann combing machine. In the main it is similar to the machine previously described, but there are some alterations in detail which require explanation. One of these is shown in elevation and plan in Figs. [121] and [122], and is an improvement in the mode of working the detaching rollers, which it was shown have to revolve a little distance in each direction alternately. This motion is placed at the end of the machine, and consists of a large cam F, which is suitably driven and with which a bowl fastened in quadrant C engages. C is formed on its outer edge with a toothed rack, which engages with the pinion B, loose and sliding upon the spindle of the detaching roller C1. B is part of a toothed clutch, as shown at E, and has a ring groove formed on its boss, with which a claw at the end of the lever G engages. The sliding half of the clutch is usually drawn inwards by the spiral spring shown in the plan, so that the normal tendency of the two parts is to engage. At the end of the lever G a pin carrying a bowl is fastened, the latter being constantly in contact with a cam surface fixed on the shaft on which the cam F is secured. The action of this mechanism is easily understood. The cam surface which actuates the lever G at the moment when the detachment of the tuft of cotton is completed, allows the clutch to become engaged. Simultaneously with this the cam F causes the quadrant to make its stroke, and thus rotate the detaching roller C1 as much as is required when the lever G is moved, so as to disengage the clutch, and the detaching roller is free to revolve. The advantage of this motion is principally its simplicity, which causes it to be easily worked at a high speed without endangering its positive action. It can readily be adjusted to suit different staples of cotton, without any change pieces.
Fig. 120.J.N.
(203) Referring now more particularly to Fig. [120], it will be noticed that a change is made in the construction of the nippers. In the machine as usually constructed, the lower blade H is used as a cushion, being covered with leather, an operation which is a somewhat delicate and difficult one. In Messrs. Dobson’s machine the lower nipper blade H is made a somewhat blunt V shape, while the upper blade or knife D is fitted with a narrow strip of india-rubber or leather. The nip is obtained between these surfaces, and owing to the yielding nature of the strip, an efficient grip is always established. As a corollary of this the lower nipper blade D is fixed, and does not yield as in the ordinary mode of construction. The cam for working the nipper is shown at K, and its motion is communicated through the lever and rod G. Its shape is such that it works easily and smoothly without any difficulty, at a speed of from 80 to 95 nips per minute.
(204) In order to avoid misapprehension, it may be as well to say at this point that the mechanism employed being similar to that in the ordinary machine, the various parts are all marked with the same reference letters in each case. The cotton is marked Z and its passage through the machine can be clearly followed. This will avoid any special reference to the mechanism common to both machines. The leather roller Q is in this case carried at the ends of two levers R, which are coupled directly to the lever W, which receives the necessary reciprocal motion, and the joint X at the end of W is so arranged, that it can be very readily set. The setting is very easily made, and as the operation of the “leather” or “piecing” roller is one of the most delicate in the machine, any means by which this can be more readily adjusted is of importance. The top roller T is made of a large size, so as to press well down upon the detaching roller, and not to vibrate, however high the speed of the machine may be. A minor improvement is made by arranging that as the bristles of the cleaning brush wear, they can be driven at a quicker speed.
(205) Although the Heilmann machine has been in use for about 40 years, it is a singular fact that no other machine for the same purpose has had anything like the same success. A machine, invented by Mons. Imbs, has been used to a certain extent on the Continent, but it has not been adopted except in a small percentage of the cases in which the Heilmann has been used. A machine, which is extremely ingenious in its mechanism, and which has been a little used for short stapled cotton, is the joint invention of Messrs. Pinel, Lecœur, and Hetherington. In this machine the principle of a revolving nipper is adopted. A long pipe forms the main moving piece of the machine, and is of sufficient length to constitute six heads, its circumference being divided into three parts. For each head three longitudinal slots are cut in the pipe equal in length to the width of the lap. Three sets of nippers are fitted to each head, the fixed jaw of each coming up to the edge of the slot, which, when the nipper is closed, is covered by the loose jaw. When the nipper is open the slot is exposed. Between each pair of nippers is placed a comb segment with thirteen rows of needles. A feed nipper presents the end of the lap to the needles, the pipe then revolving at its highest speed. When the end of the lap has been combed the revolving nipper comes opposite the feed nipper, which is stationary, and the pipe revolves at a slower speed to allow the combed end of the lap to be drawn into the nipper. This is effected by the suction of an air current induced by a fan connected to the tube. This operation being completed, the revolving nipper closes on the lap and the feed nipper allows a short length of lap to be taken through. The separation of the tuft is then made, and its other end is combed by being drawn through a top comb as in the Heilmann. The pipe then continues to revolve, and while the next in the series of nippers is taking its feed, the one holding the combed tuft opens slightly on arriving at a table placed at the front of the machine. By the aid of a pusher the fibres are superposed on those already on the table, a continuous fleece being thus made which is taken forward by two pairs of draw rollers. The sliver is made exactly as in the Heilmann. The Lecœur machine is not suitable for long stapled cotton, but it will comb very effectively the short Indian and American staples. Of these it will produce 400lbs. per week, with a per centage of waste of from 16 to 20. It is only in special cases that the combing of this class of cotton is remunerative.