Geometry of shed

Size of Shed

•      The size of the shed is very critical. It should allow a secured weft insertion. 

•      Shed size can be expressed in terms of the front shed angle.

•      The shed angle may be as low as 15° to 18° on a gripper projectile weaving machines.

•      In general, the reduced shed may be used with the smooth warps, for example, with the filament warps.

•      It cannot be used with low-grade warps because the sticking warp ends

cannot be separated in a small shed.
Shed angle should not exceed 25° with very poor warps because it would require an excessive lift of the farthest healds shafts from the beat-up line.

Timing of the shed opening

•      Timing of the shed opening is also critical.
Healds cross at 0 °

•      Heald shafts become level when the reed is at its most forward Position.
Healds cross at 270 °

•      Heald shafts become level well before the reed reaches its most forward Position.

    When the reed is at the front dead, a new shed is partly opened. The timing of shed opening is earlier than the former one.
The relative timing of 'the shed change’ with respect to the reed beat up can be adjusted.