Essential Parts which are Used in Weft Insertion Motion of Loom

Last Updated on 12/01/2021

Essential Parts which are Used in Weft Insertion Motion of Loom

Bhavdip Paldiya
Dept. of Textile Technology
Sarvajanik College of Engineering & Technology, Surat, India


Weft Insertion Motion
The movement of the inserted yarn in weft passage is a complex motion. It is called weft insertion motion of loom. It is not a positively controlled process.

Weft Insertion Motion of Loom
Fig: Weft Insertion Motion of Loom

Here We Explain the Some Following Parts which are used in Weft Insertion Motion of Loom:

  1. Plate spring tenser
  2. LH sensor
  3. Pre-winder
  4. Electromagnetic pin
  5. Balloon sensor
  6. Balloon breaker
  7. ABS/WBS
  8. Tandem nozzle
  9. Main nozzle
  10. Electrical cutter
  11. Sub-nozzle
  12. H1 feeler
  13. H2 feller

1. Plate spring tenser:
Thread a weft through the tenser. (Be sure to thread a weft between the leaf springs of the tenser.)

Plate spring tenser
Fig: Plate spring tenser


  • Plate Spring Tenser
  • Plate Spring
  • Adjusting Nut

2. LH sensor:
This LH sensor detects the presence or absence of a weft yarn at the preset timing. If it detects a weft yarn, the machine continues running, if no weft yarn, the machines stop.

LH sensor
Fig: LH sensor

3. Pre-winder:

  • Adjust the drums height 1& 2 at an equal distance from the horizontal center-line assumed between tandem nozzles. Drums head 1& 2So that its center line passes the center of the inlet of tandem nozzle. Drums should be tilted down 14 degree from a horizontal position.
  • Right to left position the electric drum unit so that the distance from balloon cover to tandem nozzle comes to 50 mm. The distance from electromagnetic pin to tandem nozzle should be approx. 400-420 mm.
  • Adjust drum head 1& 2 to the front or rear so that its center line passes the center of tandem nozzle & main nozzle. Adjust the height of chesses tensor and eyelet front to rear positioning. By using push button, feed a weft yarn into the drum. Yarn feeding air is supplied from main tank.

Name of Components:

  • Winding Sensor
  • Electromagnetic Pin
  • Measuring Band
  • Measuring Bands
  • Cover
  • Motor
  • Inlet Piece
  • Winding Arm
  • Push Button
  • Adjust Bracket
Fig: Pre-winder

4. Electromagnetic pin:
This pin measures the length of a weft yarn for one pick. Make the clearance between this pin & measuring band 0.5 to 0.8 mm.

Electromagnetic pin
Fig: Electromagnetic pin

5. Balloon Sensor:

  • This sensor detects the number of weft winding on measuring bands and is the first turn, second (n-1) th turns and nth turn. Adjust the clearance between the sensor and the measuring band to 0.5 to 1.2 mm.
  • Measuring length = Drawing in width + Waste selvedge in length.

6. Balloon breaker

  • The balloon breaker makes the filling balloon small to reduce release tension and filling insertion resistance. It is required to operate the loom stably with weak filling.
  • It controls the balloon size and pressure of the main nozzle. It guides the weft thread,
Balloon breaker
Fig: Balloon breaker

7. Weft Break System (WBS):

  • WBS Weft Brake System prevents broken picks and slack picks.
Weft Break System
Fig: Weft Break System
  • Braking force is applied to the filling just before the insertion is completed. This reduces the velocity in order to greatly reduce peak tension. Decrease of broken picks improves quality and operation. Loom speed can be increased.

***Prevents many common problems such as:

  • Broken Pick
  • Slack Pick
  • Intertwining
  • Long & Short Pick
  • High-Twisted and Elastic Yarn Returning

8. Tandem Nozzle:

  • Set the crank angle at 90-degree. Set the dimension at 21 mm. Angle at about 10 degree so that tip and of the accelerating tube of tandem nozzle comes to the center line of main nozzle. Up down positioning at left adjust tandem nozzle & so that their center lines pass the center of drum head 1&2 and of thread guides respectively according to the following procedure.
Tandem Nozzle
Fig: Tandem Nozzle
  • Adjust distance between the top of tandem plate & the top of the tandem nozzle one bracket to 165mm & second bracket to 60mm. Adjust the inclination of tandem nozzle & so that the distance between their tips becomes 48mm.

9. Main Nozzle:

  • The right to left positioning of main nozzle that adjust slay so that distance from its left end to the left most dent of reed comes to 215 mm. Adjust main nozzle so that distance from the tips of their acceleration tubes to the left most dent comes to approx. 11 mm.
Main Nozzle
Fig: Main Nozzle
  • The standard clearance between thread guide & lock nut is approx. 3.5 mm. clean sides of thread guide & side of main nozzle body with a clean cloth or an air blower. Insert thread guide straight into main nozzle body until its locks become engaged.

10. Electrical Cutter:
The Electrical Cutter Solves the Difficulty of Fine Adjustment.

  • The cutter timing of the main nozzle can be set on the i-board. (Easy adjustment)
  • The tension in filling cutting can be adjusted according to the filling type even during operation.
  • Because the cutter is inoperative during APR operation, it is unnecessary for the defective pick to escape from the cutting area. (Easy adjustment for blowing-up, increase of success ratio of the APR)

11. Sub Nozzle:

  • Sub nozzle is placed in front of reed. Air is jetted in order to transfer the inserted weft through main nozzle over the entire machine width. 4-sub valve is use in machine.
Sub nozzle
Fig: Sub nozzle
  • Each sub valve has 4-sub nozzle join to it. Connect an air pipe to sub nozzles, then tighten the nut fully by hand. Rotate fixing nut by 360 degree with a spanner. The height & angle of sub nozzle may be changed upon the texture type to be woven.

***Arrangement of sub nozzle:

  • Distance between H1& H2 feller =125mm.
  • Distance from the left most warp to the first sub nozzle =30mm.
  • Distance between sub nozzle in the central zone of fabric =60mm.
  • Distance from the right most warp to the last sub nozzle = (30-60) mm.
  • Distance between last sub nozzle & H1 feeler = (25-30) mm.
Arrangement of sub nozzle
Fig: Arrangement of sub nozzle

12. H1 feeler:
H1 feeler detects the presence or absence of a weft yarn at the preset timing. If it detects a weft yarn, the machine continues running, if no weft yarn, the machines stop.

H1 feeler
Fig: H1 feeler

12. H2 feeler:
H2 feeler detects the presence or absence of weft yarn at the preset timing. If it detects no weft yarn, the machine continues running, if it detects any weft yarn reaching the H2 due to a broken or blown-off weft trouble the machine stop.

The Distance Between H1& H2 Feeler Is 125mm
Fig: The Distance Between H1& H2 Feeler Is 125mm

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