Question

Pick finding in modern looms include the

• A. Heald crossing motion
• B. Warp easing motion
• C. Cylinder turning motion
• D. Index wheel turning motion

Hint:

• Pick finding An operation to remove a faulty weft pick and reset loom mechanisms to restart weaving correctly after a loom stop (e.g., due to weft break).
• It involves coordinated reverse or adjusted movements of shedding, sley, take-up, etc.
• All these movements are synchronized with the main shaft} of the loom.
• "Index wheel turning motion" implies the controlled rotation of this main shaft to achieve the correct phase for pick finding. This is the most encompassing description of the control aspect.

Answer 1

The Correct Option is D

Pick finding is an operation performed on a loom after a stop, usually caused by a weft break (or sometimes a warp break). Its purpose is to: % Option (A) Remove the broken or faulty pick from the shed if it was partially inserted. % Option (B) Bring the loom mechanisms (shedding, sley) back to the correct position (typically, shed open, sley back) ready for the insertion of the next pick, so that weaving can be restarted without a defect (like a mispick or a starting mark). Modern looms have automatic or semi-automatic pick finding systems. These systems involve coordinated reverse (or forward and then reverse) movements of several loom mechanisms:

• Shedding mechanism (Healds/Jacquard): Needs to be brought to a specific shed position (often open shed for the pick that failed, or to the point just before that pick).
• Sley (Reed): Needs to be moved back from the fell.
• Take-up motion: May need to be reversed slightly to release cloth tension and allow removal of a faulty pick.
• Let-off motion: May need to be coordinated.
• Weft insertion system: Needs to be ready for the next pick.

All these motions are timed relative to the main shaft of the loom. The "index wheel" indicates the angular position of this main shaft. Let's evaluate the options for what "pick finding ... include the":

• (a) Heald crossing motion: The healds (or Jacquard elements) control the shedding. During pick finding, the healds must move to open the correct shed or to facilitate removal of a broken pick. "Heald crossing" refers to the point where healds are level during shed change. This is a part of shedding motion, which is involved.
• (b) Warp easing motion: Warp easing (or warp let-back) is a mechanism that slightly releases warp tension, especially when the shed is fully open, to reduce strain on warp yarns. This might be activated during pick finding or loom stop/start to manage tension.
• (c) Cylinder turning motion: This could refer to the pattern cylinder of a dobby or a Jacquard cylinder if it's an older mechanical type. These control the shedding sequence. Reversing or adjusting these cylinders would be part of repositioning the shedding mechanism.
• (d) Index wheel turning motion: The index wheel itself is a passive indicator of the main shaft position. However, "index wheel turning motion" implies the controlled rotation of the main shaft (to which the index wheel is attached) either forwards or backwards to bring all loom mechanisms to the correct synchronized position for pick finding and restart. Modern automatic pick finding systems achieve this by precisely controlling the rotation of the main shaft.

Pick finding requires the entire loom to be brought to a specific phase in its cycle. This is achieved by turning the main shaft (and thus the index wheel) to the desired angular position. The other listed motions (healds, warp easing, pattern cylinder) are *consequences* or *parts* of the coordinated actions controlled by the main shaft's positioning during pick finding. Therefore, the fundamental action that underpins the entire pick finding sequence is the controlled "turning motion" of the main shaft, which is reflected by the "index wheel turning motion". This option represents the overall coordinated control. \[ \boxed{\text{Index wheel turning motion}} \] (Interpreting this as the controlled rotation of the main shaft, which the index wheel follows and indicates.)