To look at it, one would imagine it to be—what it really is—one of the simplest pieces of mechanism possible, yet the actions performed by it are complex and beautiful in the extreme. Later on, these actions of the Quadrant will be carefully examined.
Fig. 26.—Mule head showing quadrant.
The self-actor mule is an intermittent spinning machine, i.e., it is not continuous in action, as are most machines used in the making of thread or yarn from the fibrous product of the Cotton plant. Take for instance the Carding Engine, and the bobbin and fly frames, as previously described. So long as these machines are working, practically all of the acting parts of the mechanism have a continuous forward motion.
This is by no means the case with the machine now under consideration, as many of the more important and principal parts move alternately in opposite directions, while other of the less important may revolve at one time, and be stationary at another.
What are called the medium counts of yarn contain say from 30 to 50 hanks in one pound avoirdupois; a cotton hank being equal to 840 yards, so that one pound of 40's yarn will contain no less than 40 × 840 yards or 33,600.
For such yarns as these, a modern self-actor mule would probably go through its cycle of movements four times per minute. For coarser or thicker yarns this speed might be increased, while for finer and better qualities of yarn the speed would be diminished.
Now as each succeeding "stretch" marks a complete cycle of movements and is a repetition of others, it will probably suffice if a brief non-technical description of one of these "stretches" or "draws," as they are termed in mill parlance, be given.
As in the bobbin and fly frames, the bobbins containing the rovings of cotton to be operated upon, are placed behind the mules on skewers fitted in a suitable framework of wood and iron called "creels," so as to allow the cotton to be easily pulled off and unwound without breaking. These rovings are guided to and drawn through three pairs of drawing rollers (see [Fig. 27]), which shows this very fully.
The chief difference between these rollers and those of the previously described machines being in the lessened diameters of the mule rollers, and consequently attenuating the cotton to a much greater extent. It is a truism well understood by those in the trade, that the finer the rovings are the better the raw cotton must be, and the more drawing-out they will stand in any one machine. One inch of roving put up behind the rollers of a mule spinning medium numbers would probably be drawn out into 9 inches.