Timing.
All the contrivances just described are required to work harmoniously in order to produce the desired results, each coming into action at the proper time. In plain cloth weaving, when the crank is at the fore centre, the reed touches the cloth at right angles, and the healds are slightly open, forming a new shed. As the slay moves backwards just in front of the bottom centre, the picking band is tight and just commencing to move the shuttle. At this point the healds are full open and remain so until the crank has passed the back centre, when, as the shuttle has arrived in the opposite box, the shed begins to close. Before the slay has reached the front again, indeed when just past the top centre, the healds are level; an advantage is thus gained in having the rods crossed on the weft at the time it is beaten up, holding it firmly. The sector lifts the greyhound tail for the weft stop motion at the moment that the reed touches the cloth, when the fork would be lifted if there were weft in the loom. This only happens, of course, every alternate pick, when the shuttle is at the fork side of the slay. Generally the monkey tail on the slay sword moves the take-up pawl as the slay moves back, just dropping the holding catch as the crank reaches the back centre.
The reed is held tightly in a loose reed loom when the slay approaches the front. Of course, the timing of the motion varies under different circumstances; if cloth is being woven as wide as the loom will possibly admit of, or if the shuttle boxes be short, then picking necessarily must take place later, as the shuttle starts so close to the cloth; consequently, shedding must be later or the shed will close before the shuttle is through. Of course in this case the pick must be stronger, as the shuttle has more friction in its traverse. Other circumstances also affect the timing.