One of the most important of the early inventions in the textile art was the cotton gin. This was the invention of Eli Whitney, of Massachusetts, and was patented by him March 14, 1794. Prior to its use the picking of the cotton fibre from the bean-like seed with which it is compactly stored in the boll was entirely effected by hand, and it was a slow and tedious process, and about 4 pounds per day was the average work of one man. The cotton gin, shown in [Fig. 288], is a device for doing this by machinery in a rapid, thorough, and expeditious manner. The cotton, mixed with seed, is fed to the roll box J, in which a sort of reel F continually turns the cotton. The bottom of the roll box is formed with a grating of parallel ribs E, between which project the teeth of a gang of circular saws C, which pull the fibre through between the ribs and deliver it to the revolving brush B, which beats the fibre off the teeth of the saws and produces a blast that discharges the fleece through the rear of the gin. The cotton seed, which are too large to pass between the ribs with the fibre, drop out the bottom of the roll-box. With the aid of the cotton gin the efficiency of one man is raised from four pounds per day to several thousand pounds per day, and the culture and manufacture of cotton fibre was revolutionized and greatly stimulated by providing a mode of putting it into merchantable condition at a reasonable price. It is said that the crop of cotton increased from 189,316 pounds in 1791 to 2,000,000,000 pounds in 1859. The cotton gin, as invented by Whitney more than a hundred years ago, is still in use, substantially unchanged in principle, but its efficiency has been raised from 70 pounds per day to several thousands. The cotton crop of the United States for 1899, which was handled by the modern gins at this rate, amounted to 11,274,840 bales, of about 500 pounds each, or more than five thousand million pounds. But for the cotton gin this great staple would have only a very limited use, and one of the greatest of the world’s industries would have practically no existence.
FIG. 288.—COTTON GIN.
FIG. 289.—
MODERN
SPINNING
SPINDLE.
A modern step of importance in spinning was the ring frame. Ring spinning was invented by John Thorp, of Rhode Island, who took out two patents for the same November 20, 1828. The leading feature of the ring frame is the substitution of a light steel hoop or traveler running upon the upper edge of a ring surrounding the spindle in lieu of the flyer formerly employed. The thread passes through the hoop as it is wound upon the spindle. In modern times ring spinning has attained considerable proportions, especially in cotton manufactures.
Nearly 3,000 United States patents have been granted in the class of spinning, and many valuable improvements in the details of construction in spinning machinery have been made in recent years. The most important, perhaps, are those relating to spindle structure, whereby the speed and efficiency of spinning machines have been greatly increased. Prior to 1878 the speed of the average spindle was limited to 5,000 revolutions a minute. In 1878 improvements were made which doubled its working speed and permitted as high as 20,000 revolutions a minute. This result was accomplished by making a yielding bolster. The bolster is an upright sleeve bearing, in which the spindle revolves, and against which is sustained the pull of the band that drives the spindle. By making this bolster or sleeve bearing to yield laterally by means of an elastic packing which surrounds it, a much greater freedom and speed of revolution were obtained. The preliminary step in this direction was made by Birkenhead in patent No. 205,718, July 9, 1878. In the same year this idea was perfected by Rabbeth. The bolster was placed loosely in a bolster case of slightly larger diameter than the bolster, and the bottom of the spindle had a free lateral movement as well as the top, as shown in his patent No. 227,129, May 4, 1880. With such perfect freedom of movement, the spindle at high speed could find its own center of revolution, and an indefinitely high speed and quadrupled efficiency were attained. The Draper Spindle is shown in [Fig. 289] as one of the most modern and representative of spinning spindles. Considering the great speed of the modern spindle and the fact that a single workman attends a thousand or more of them, the record of progress in this art becomes impressive. In 1805 there were only 4,500 cotton spindles at work in the United States. In 1899 there were 18,100,000.