GB760783A - A picking device for shuttleless weaving looms - Google Patents

Abstract

760,783. Shuttleless looms. MIRA, ZAVODY NA PLETENE A. STAVKOVE ZBOZI, NARODNI PODNIK. Aug. 27, 1954 [Oct. 1, 1953; Oct. 10, 1953], No. 24980/54. Class 142 (2). A weft measuring device for looms in which the weft is inserted by a jet of air or water produced by a nozzle 19, comprises a rotating drum 1 having a smooth portion 1a round which the weft thread is guided by eyelets 13, 17, and a helical groove 4 into which the thread is guided by a claw 6 rotating with the drum. At first, a clamp 18 between the drum and the nozzle is closed, but after one- and-a-half turns (for example) have been wound on, the friction between the thread and the drum is sufficient to pull the thread through a tension device 15 ; the clamp 18 is then opened. A plate 10, rotating slightly faster than the drum, now overtakes the claw 6 and begins to push the thread out of it, thereby causing thread to be drawn back through the nozzle 19 to bring the cut end to the position required for the next pick. When the plate 10 has freed the thread from the claw 6, the nozzle 19 operates to project the thread into the shed, the coils on the drum being pulled off endwise. At first, thread from the supply 14 continues to be wound on the drum, but when most of the coils have been pulled off, the friction between the remaining coils and the drum becomes insufficient to overcome the tension device 15, whereupon winding ceases. The loop of thread between the eyelets 13, 17 slips on the surface 1a of the drum until the clamp 18 closes and the claw 6 initiates another cycle. In another construction, two weft threads pass round, and normally slip on, smooth portions of the drum, additional eyelets on levers operated by pattern mechanism bringing the selected weft into range of the claw to be wound on the drum. Fig. 3 shows a nozzle used for two threads. Fluid pressure in the space 48 tends to open valves 49 by moving them away from the exterior of jets 50 through which the weft threads pass ; electromagnets controlled by pattern mechanism attract armatures 41 to keep one or both valves closed at the required times. Specification 693,751 is referred to.