GB701967A - Improvements in or relating to yarn-cutting arrangements in automatic looms - Google Patents

Abstract

701,967. Cutting weft in automatic looms. NATIONAL RESEARCH DEVELOPMENT CORPORATION. June 18, 1951 [June 16, 1950; Jan. 30, 1951]. Nos. 15163/50, 2370/51. Class 142(2) A device for severing the weft yarn extending from an expended pirn which is to be replaced in the shuttle by a full one comprises a notched member 1 adapted to be actuated by the sley, shuttle box or shuttle and slide between a cutter 2 and a clamp 8 so that the yarn caught in the notch 4 is severed and held. To prevent immediate release of the yarn after severance and upon return of the sley, the member 1 has a piston portion 10 slidable in a cylinder 9 against a spring 11 and when actuated forces air from the cylinder out of a non-return valve 12, the return movement being controlled by an air inlet in the side of the cylinder S. Further movement of the member 1 is permitted, after severing and clamping a yarn, by mounting the cylinder 9 in a body portion 13 and causing it to act against a spring 14 but which is of sufficient strength to prevent relative movement of the cylinder and body portion until the clamping and severing action is complete. An alternative mounting for the cylinder comprises links 69, 610, pivotally secured to the cylinder and a fixed member of the loom, and a coil spring 615 connected to the link 69 and a pillar 617 so as to act as a strut during the initial movement of the device. Further movement overcomes the strut action and causes the spring to bend and permit movement of the cylinder. In the arrangement the notched member may be freely slidably mounted in the cylinder but having a piston arrangement which controls the member on its return movement only by permitting only a gradual air flow past it and a slow return of the member under its own inertia. In another arrangement, the spring acts as an over centre lever to hold the device in a fully advanced or retracted position and in this case a lever mechanism for returning the device to its operative position is provided. To facilitate engagement of the yarn by the notched member the shuttle may be recessed and lined with a strip of material engaged by the yarn to prevent formation of a slack loop in the shuttle eye.