Hook and Needle Selection Principles
topic
Jacquard machines select individual hooks for raising by engaging a selection element with the hook knife that lifts all engaged hooks simultaneously, with the selection mechanism using punched cards pressing needles through holes to engage hooks in mechanical Jacquards, electromagnetic coils attracting or deflecting selection elements in electronic Jacquards, and piezoelectric or shape memory actuators in specialised high-speed systems, with the selection cycle completing for each pick insertion to update the raised hook configuration.
Role
Implements the individual end control that distinguishes Jacquard from dobby by providing a unique selection decision for each hook position per pick rather than grouping ends on shared shafts, with selection mechanism reliability being the most critical performance parameter governing the defect rate in Jacquard fabrics where a single missed selection produces a visible fabric defect, requiring selection success rates above 99.99 percent for acceptable fabric quality.
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