Picking Mechanism involves the insertion of the weft yarn through shed across the width of the warp sheet. The picking mechanism is especially a function of the picking media, used for the insertion of the weft. The picking media vary greatly on the idea weft velocity and therefore the insertion rate; and are classified into the shuttle and shuttle-less picking.
It is the oldest technique of weft insertion on the loom. The picking media may be a wooden shuttle that traverses back and forth across the loom width. A pirn or quill having yarn wound thereon is placed inside the shuttle. because the shuttle moves across, the yarn is unwound and placed within the shed. A picking stick on all sides of the loom helps to accelerate the shuttle by striking it. The shuttle travels on the race board, above the lower portion of the warp sheet. The shuttle picking takes place from both the edges of the loom.
Introduced first time by Sulzer in 1952, this machine uses a little metallic projectile alongside gripper to throw the wet yarn across the loom width. The energy required for the propulsion of the projectile into the shed is provided by twist within the torsion rod. The projectile glides through guide teeth within the shed. It had low power consumption, the versatility of yarns, and a better weft insertion rate as compared to the shuttle picking system.
Rapier Picking – Picking Mechanism
This picking system uses a rigid or flexible element called rapier for the insertion of weft yarn across the shed. There are two major variations within the rapier picking; single rapier and double rapier. just in case of a single rapier picking system, the rapier head grips the weft and carries it across the shed to receiving end. The rapier has got to return empty to insert the new weft. The double rapier picking as well as makes use of two rapiers. One rapier (giver) takes yarn to the center of the machine and transfers it to the opposite rapier (taker), which brings the weft to the other side.
Water Jet Picking
The water jet picking involves the insertion of weft yarn by highly pressurized water. This pressurized water takes the shape of a coherent jet thanks to the surface tension viscosity of water. The flow of water has three phases: acceleration inside the pump, jet outlet from the nozzle, and flow into the shed. the quantity of water used for the insertion of 1 pick is a smaller amount than 2 cm3. this technique is usually preferred for the synthetic yarns.
Air Jet Picking – Picking Mechanism
In the air-jet picking system, the weft is inserted into the shed by the utilization of compressed gas. The yarn is taken from the availability package/cone and wound on to the feeder before insertion to avoid tension variations. The weft is then skilled the most nozzle which provides initial acceleration to the yarn. The auxiliary nozzles are present at specific distances along the width to help in weft insertion. A special sort of reed called profiled as well as reed is employed for air-jet picking. The channel within the reed guides the yarn across the shed and avoids entanglement with warp. it’s a particularly high weft insertion rate.