A device, the invention of which greatly increased the speed at which cloth could be made of spun yarns. The loom used for weaving contains a means of lifting selected warp yarns above other warp yarns, forming a space called a shed through which the weft is passed. Such devices cannot function unless the warp is under tension, so all looms also contain in means for stretching the warp. There are many different method of stretching the warp and of forming sheds, ranging from the very simple to the very complex.