Mechanical Chain and Peg Board Dobby Systems
topic
Mechanical chain dobby systems store the lifting programme on metal chains with pegs or lags in positions that engage dobby hooks for raised shafts, with chain length determining pattern repeat and chain changing requiring the preparation of a new chain assembled from individual lags following the paper point draft, while peg board dobbies use cards or bars with holes indicating raising positions that are read mechanically, both systems being largely superseded by electronic dobby but remaining in service on older loom installations.
Role
Represents the historical technology that preceded electronic dobby and whose understanding is relevant for technicians maintaining older loom installations and for appreciating the design constraints that shaped dobby fabric traditions before digital control, with the physical chain preparation process that took hours for complex patterns illustrating the productivity advantage of electronic dobby's instant pattern change capability that transformed dobby weaving economics.