Catalogue of mechanical engineering collection in the Science Division of The Victoria and Albert Museum Volume 2 - Softcover
Synopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 Excerpt: ...breaking, and heckling. In making the hemp into rope, the coarseness of the fibres and their great length, about 3 ft., have rendered the advantages of machine over hand work less pronounced than in many industries, so that hemp is still extensively spun by hand, assisted only by the very primitive machines of a rope-walk. The spinner wraps a quantity of prepared hemp round his waist, and then pulling forward a tuft, twists it and attaches it to a hook at one end of the walk. This hook, or whirl, is rapidly rotated through multiplying wheels by an assistant, so twisting the fibres into a yarn, while the spinner walking backwards continues to feed more fibres, end on, into the yarn, until he reaches the limit of the walk, sometimes 400 yds. After some minor operations, the completion of the rope is proceeded with. by combining three or more of these yarns into a single cord in such a way that there shall be no tendency for the rope to untwist. This process, known as laying, is of great interest, and in a rope-walk is performed by attaching the three strands at one end to a single hook on a carriage at one end of the walk, and the other end of each yarn to separate hooks at the other end of the walk. The three yarns are at first consolidated by twisting each separately, and then the three strands are twisted into a single rope by the revolution of the single hook on the carriage, which slides up as the twisting reduces the length. When the strands are twisting together, their individual hooks are being revolved at the same rate as the main single hook, so that the twist of the fibres of the strands is not altered by the laying twist. A conical plug of wood with three grooves in it, called a lay-top, is squeezed along the three strands as they close together, ...
"synopsis" may belong to another edition of this title.
