Dobby Shedding Mechanism | Scope of a Dobby

Last Updated on 01/04/2021

Experiment name:
Study on Dobby shedding mechanism.


  1. To know about the different parts formed this shedding.
  2. To learn the mechanism of dobby shedding.

What is Dobby and Dobby Shedding?
Dobby is a compact, electronically or mechanically guided shedding motion. Dobbies normally are capable of having up to 28 shafts.

Dobby is a shedding mechanism placed on the top of the loom in order to produce figured patterns by using large number of healds than the capacity of a tappet. Dobby is also known as a “witch or “wizard”. Dobby shedding is more complex and versatile shedding motion.

dobby shedding in loom
Fig: Dobby shedding in loom

Dobby shedding is two types; negative dobby shedding and positive dobby shedding.

Scope of a Dobby:
The scope of dobby is limited between a tappet and a jacquard. The number of shafts that can be actuated by a dobby varies between 6 and 40. Theoretically dobby can control 48 shafts (maximum). However, practically it can control 36 shafts in case of wool and allied fibers. Again, for cotton and allied fibers, it can control maximum 24 heald shafts. In these case healds are operated by jacks and levers.

Main Parts of Dobby Shedding:

  1. Bottom shaft
  2. L-lever
  3. Upright shaft
  4. T-lever
  5. Upper draw knife
  6. Lower draw knife
  7. Upper hook
  8. Lower hook
  9. S-lever
  10. Bulk lever
  11. Thumb lever
  12. Jack lever
  13. Healdshaft
  14. Returning spring
  15. Motor
  16. Crank shaft
  17. Pattern cylinder
  18. Pattern chain

Dobby Shedding Mechanism:

Dobby Shedding Mechanism
Fig: Diagram of Dobby Shedding Mechanism

Here a climax dobby is described to explain the dobby shedding mechanism. Climax dobby is a double lift double jack-lever negative dobby. Here two jack levers are operated by a single bulk lever. They are joined with the bulk lever by a timber lever and a link. The double lever is fulcrum med at a point and is connected with S-lever. The S-lever controls two hooks, one upper hook and one lower hook. The hooks are controlled by feelers. One hook is controlled by hooked feeler and other by a connecting needle. The two hooks control two knives that are joined with a T-lever. The T-lever is fulcrum med and is controlled by an upright shaft and an L-lever. They get motion from motor and machine pulley. When the feeler comes in contact with a peg and when it is not in the contact it goes down.

dobby peg plan
Fig: Dobby peg plan

Dobby loom is important for its use. We can use 8-12 heald frame in tappet loom but if we want to use more heald frame for more decorative design then we should use dobby loom. This practical helps me to know about the dobby loom and its mechanism. I think this will help me in my future life.

You may also like:

  1. Differences between Tappet Shedding, Dobby Shedding and Jacquard Shedding Mechanism
  2. Beat-up Mechanism in Weaving Motion
  3. 7-Wheel Take Up Mechanism in Cotton Weaving
  4. Different Types of Shed in Weaving
  5. Motions of Loom and Their Functions in Weaving Machine
  6. Basic Parts of a Weaving Loom and Their Functions
  7. Different Parts of Loom and Their Functions with Pictures

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