Speeds.—Average Speed of New Looms.
| Reed Space. | Picks per Minute. | |||
| Plain. | If Dobbied. | If Drop Boxes. | If Double Cylinder Jacquard. | |
| 32 inches | 240 | 190 | 190 | 190 |
| 44 inches | 200 | 175 | 175 | 175 |
| 54 inches | 180 | 160 | 160 | 160 |
| 66 inches | 150 | 150 | 150 | 150 |
On goods with ordinary headings, the stoppages for changing shuttles, piecing ends, etc., should not be more than one minute in twelve, or 8 per cent.
Reed Space.
The reed space of a loom is measured from backboard on the one side to the fork grate on the other. Thus, what is called a 40-inch loom measures 45 inches reed space, and in it it is usual to weave cloth up to 41 inches wide, although it is possible to weave 42-1/4-inch cloth in it. A 26-inch loom has a 30-inch reed space, and will weave to 28 inches. In wider looms the reed space is about six inches above the nominal size of the loom.
Top Motions.
In [Plate VI.] are shown a number of top motions to keep the healds tight when worked from below. Each is self-explanatory, and by imagining the effect of changing the heald or healds which are up for others, the value of each arrangement will be seen. For example—take H, a 3-shaft motion, two up. If No. 2 be required up and No. 3 down, the change is made without any movement of the top pulley; if No. 1 be required down and the other two up, it will be drawn down a distance equal to the size of the shed—say 2 inches; whilst the small pulley being connected to a step pulley on the larger one, is only lifted half that distance—say 1 inch. Now, if the small one be raised 1 inch and No. 3 heald be kept still, No. 2 heald will lift 2 inches—the height desired.
It will be noted that a top motion is adapted only for one number of healds, and that the same number must be up in successive picks. Should different numbers be up at consecutive picks, a spring top as at S is used.