Roberts Loom: Difference between revisions

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==The Loom==
The Roberts loom of 1830 incorporated ideas embodied in an 1822 patent.

The frame of the loom was cast iron. There were two side frames cast as single pieces. The three cross tails were machined for an accurate assembly. The great arched rail at the top supports the healds. The front and back cross rails bifurcate at each side to give a larger binding surface.<ref>{{harvnb|Marsden|1895|p=79}}</ref>
 
The warp passes from the warp beam, passes over a friction guide roller, where it horizontally passes through the loom to a breastbeam. Here it turns vertically to the cloth beam. Even tension is essential as any variation will lead to broken threads. As the warp beam empties its effective diameter changes making the warp slacker- tension is maintained by adding a wooden pulley to the beam, around which are two turns of rope that are attached to mill weights- thus retarding the beam through friction. The cloth beam bears a toothed wheel which works a pinion. A ratchet wheel is attached with a click level to take up the slack in the cloth. This was Roberts invention.
 
The heddles are of standard construction. They are arranged in groups of four, obviously even threads and odd must go up and down alternatively but two heeddles re used for the evens and two for the odds so adjacent threads don't rub. The lower end of the heddle leaves are attached to treadles or marches. These are depressed by cam refered to as eccentrics..
 
The loom is powered by a leather steam-belt which drives the driving shaft. Here there is a flywheel to smooth the motion and a crank mechanism to drive the battens (swords) and a toothed wheel. This engages a second shaft known as the tappet shaft or wiper shaft who's job is to lower the treadles and throw the shuttle. This turns half the speed of the driving shaft, so its toothed wheel is twice the size.
 
The shuttle is thrown by two levers attached to the side frame, but activated by a friction roller on the tappet shaft. As the shuttle enters the shuttle-box at the end of its travel, it depresses a lever which acts as a brake. If this lever is no depresses then the loom is stopped. <ref>{{harvnb|Marsden|1895|pp=78-88}}</ref>
 
==Economics==