Question

Which type of weft accumulators given below are used to achieve higher W.I.R?

• A. Axial feed over end withdrawal
• B. Axial feed axial withdrawal
• C. Over end feed over end withdrawal
• D. Over end feed axial withdrawal

Hint:

• High Weft Insertion Rates (W.I.R) in shuttleless looms require efficient weft accumulators.
• Key principles for high speed:
  • Over-end feed from supply package Yarn is drawn from a large stationary package (cone/cheese) over its end.
  • Yarn is wound onto a (usually) stationary accumulator drum.
  • Over-end withdrawal from accumulator drum Yarn is pulled axially off the end of the stationary drum for insertion.
• This combination minimizes inertia effects and tension variations, allowing very high speeds.
• "Axial withdrawal" is synonymous with "over-end withdrawal" from the drum.

Answer 1

The Correct Option is C

Weft accumulators (or weft feeders) are essential for high-speed shuttleless looms. They draw yarn from a stationary supply package, store a certain length of it on a drum, and then allow it to be withdrawn at high speed with controlled, low tension for insertion into the shed. This enables high Weft Insertion Rates (W.I.R.). Let's clarify the terminology:

• Feed: Refers to how yarn is taken from the large supply package (cone/cheese) and wound onto the accumulator's storage drum.
  • Over-end feed from package: Yarn unwinds over the end of a stationary supply package. This is a low-tension, high-speed method. The yarn is then typically wound onto the accumulator drum by a rotating flyer or arm.
• Withdrawal: Refers to how yarn is taken from the accumulator's storage drum for insertion into the loom.
  • Over-end withdrawal from drum (Axial withdrawal): Yarn is pulled axially off one end of a typically stationary accumulator drum. This allows for very high withdrawal speeds with minimal tension variation as the drum itself does not need to rotate to release the yarn. The coils of yarn slip off the end of the drum.

To achieve higher W.I.R., both the feeding onto the accumulator and withdrawal from it must be efficient and capable of high speeds with low, controlled tension. The combination that best facilitates this is:

• Over-end feed from the main supply package (cone/cheese) to the accumulator system (where it's wound onto the accumulator drum).
• Over-end withdrawal (which is inherently axial) from the stationary accumulator drum into the loom's weft insertion mechanism.

Analyzing the options:

• (a) Axial feed over end withdrawal: "Axial feed" to the accumulator drum is not standard terminology for describing how yarn gets *onto* the drum from the package. If it implies winding along the drum axis, that's typical.
• (b) Axial feed axial withdrawal: Similar ambiguity for "axial feed".
• (c) Over end feed over end withdrawal: This accurately describes the principle: yarn taken over-end from the supply package, wound onto the accumulator drum (typically by a rotating element while the drum is stationary), and then withdrawn over-end (axially) from this stationary drum for insertion. This system is designed for high speeds.
• (d) Over end feed axial withdrawal: "Axial withdrawal" is effectively the same as "over end withdrawal" from the drum. So, this option is very similar to (c).

Option (c) is the most common and complete description of the high-speed accumulator principle. The "over end" part for feed emphasizes the unwinding from the large stationary package, and "over end" for withdrawal emphasizes unwinding from the stationary accumulator drum. Both contribute to enabling high W.I.R. \[ \boxed{\text{Over end feed over end withdrawal}} \]