Last updated on August 25th, 2023 at 10:05 pm
Jacquard is a shedding device placed on the top of the loom to produce large figure patterns by controlling a very large no. of warp threads separately by means of harness cords, hooks and needles. Here no heald shaft is used. Jacquard may be controlled by pegged card, punched card, punched tape etc. or by electrical means.
Single Lift Single Cylinder Jacquard is the original and the simplest type of jacquard. It works on bottom closed shed type of shedding mechanism. Here one set of knife with griffe controlled the hooks. The hooks are controlled by needles of one cranked eye and every needle is selected one hook in that pick. One neck cord with harness cord is controlled by this mechanism.
During the cycle of operation one of the faces of the cylinder together with a card is brought against the needle board. If a hole is punched in the card the corresponding needle will project through in the cylinder. the hook controlled by that needle will remain is such a position that its upper hooked end un punched will be caught by the raising knife. The un punched position of the card will press back the needle & consequently the hook controlled by that will be away from the path of the using knife. Thus the hook gets selection according to the design cut for a particular card.
When the hooks are lifted by the knives the cylinder moves out a limited distance. A catch holds it against the top corner of the cylinder. The cylinder is turned about its axis & new card is presented to the needles during its next cycle.
By this time the griffe along with its knives descend to lower the warp threads to the bottom shed line for a fresh warp threads to the bottom shed line for a fresh selection of the hook at the next pick.
By this mechanism we learn how jacquard mechanism work and how it produce decorate design by using yarn individually. Moreover it is a very helpful and important practical for our textile life.
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