Shed Staggering

Types of Shed Geometry

Control or Effect

Types of Geometry

Shed Geometry

Shed Symmetry

Whip Roller

Positive Cams

Cloth Support

Shed Staggering

Timing (cams)

Shed Depth (stroke)

Shed Clearance

Shed Height

Shed with Staggered Timing

Characteristics

With staggered timing the shed closure of the individual shaft pairs is displaced in time, to avoid all shafts crossing at the same time.

Staggered Timing Application

Staggered Timing is purposeful only where

Very high warp densities are used

Hairy yarn that separate badly are being woven

Adjustment

The selvedge shafts always cross first (at about 350o )

Then the rearmost ground shafts cross, or those standing lowest in the upper shed

After this come always two more shaft progressing for rear to front

Staggered Timing on Positive Cams

Staggered Timing on Positive Cams

Heddle Frames Height of Time Staggered Shed

Reference Line Frame 4

Frame 3Frame 2

Normal Frame HeightFrame 1

Shed Closure Line

Shed Dwell

Shed Depth

20o 160o 270o 20o 160o 270o 20o

1st Cycle 2nd Cycle

Fixed Height (Clear) Shed

Characteristics

When an ideal shed the ends of the upper and bottom sheds each form an ideal, closed sheet.

A slight staggering in height may be observed in the bottom shed, that can be tolerated.

Clear Shed Application

For filament yarn fabrics, such as linings

For lightweight fabrics whose ends part well

For non-elastic fabrics like glass-fiber

For polyethylene and polypropylene ribbons

For twills woven from staple fabric

This adjustment is inadvisable for dense warp sheet, poor parting warp ends.

There are chance of end cut in case of projectile loom.

Staggered Height Shed

Characteristics

With staggered shed the shafts are adjusted offset in height, so that the upper and bottom sheds consist of several thread sheets

Staggered Height Shed Application For dense warp settings

For hairy, badly parting warp yarns

For fabrics with many shafts crossing at the same time

For skipping and warp ends cut on projectile looms

For warps sized too soft

Effects Owing to the differing height of individual shaft pairs, at

change of the shed the shafts cross in different planes. This gives the threads more room, they hinder each other less and the shed divides better.

Shed Height and Shed Depth

Front shed with all frame with same depth(stroke) and Increasing Height towards loom back

Front shed with Increasing depth(stroke) and Height towards loom back

Shed Height and Shed Depth

Shed Height and depth adjustment on Sulzer and Staubli Cam Shedding System

Shed Types w.r.t. Shed Closing Position of

Shed Types

w.r.t.

Shed Closing Position

Bottom Close Shed

Center Close Shed

Semi Open Shed

Open Shed

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