1837 Crompton's Patent Model of a Power Loom

Before William Crompton’s 1837 patent for a fancy power loom was adopted, the harnesses of power looms were controlled by cams. This arrangement limited the number of harnesses that could be utilized, which in turn limited the complexity of patterns that could be woven. In order to vary the pattern, the cams had to be laboriously changed. Crompton’s invention solved both of these problems. In his patent, an endless pattern chain was used, upon which rollers or pins could be variously placed to engage the harness levers (as had the cams) but which allowed any number of harnesses to be used and easily permitted the changing of patterns. Now more elaborate designs could be easily woven on power looms.