Patent GB-864654-A (GB)
Title: Improvements in and relating to the joining of yarns
Inventor: MACKIE JOHN KAY PRINGLE
IPC: B65H69/04
Filed: 1956-05-23
Abstract: 864,654. Knot-tying devices. JAMES MACKIE & SONS Ltd. May 15, 1957 [May 23, 1956; Aug. 2, 1956; Feb. 14, 1957], Nos. 16033/56; 23937/56 and 5146/57. Class 112 Knotting mechanism comprises a frame rotatable in its own plane, means for deflecting a portion of a strand of two yarns to be joined out of the plane of the frame so that rotation of the frame causes the strand to make one revolution round the frame, means for causing a further portion of the strand to enter the frame and to lie therein across the said convolution, means for pulling the convolution over the end of the frame while leaving the said further portion of the strand within the frame, and means for tensioning the yarn so that the portion of the strand within the frame is brought into contact with a cutting edge through which it is severed. As shown in Figs. 1 and 2, mechanism for tying a thrum knot in a strand of yarns A, B comprises a rectangular frame 14 having one long side formed by a member 15, the other long side and a short side formed by a member 16 having a curved end, and the other short side formed by a block 17 to which member 15 is fired and on which member 16 can pivot about a pin 20, block 17 being carried by a shaft 18 whereby the frame can be rotated in its own plane. At the commencement of the operation the yarns pass between separated feeding rollers 12, in front of frame 14, between separated clamping jaws 21 and into a suction duct 10. Frame 14 then rotates counterclockwise and shaft 18 is reciprocated axially, whereby the strand is wound in a convolution around frame 14, Fig. 1 (5). The frame continues to rotate through a further 180 degrees, during which period member 16 opens and closes to entrap a loop of the strand, the latter assuming the formation shown in Fig. 2 (7). Further rotation of the frame to a position 25 degrees short of its original position, causes the convolution to slip over the end of the frame and to pass over the loop held by the latter to assume the conformation shown in Fig. 2 (8). The frame then stops and the jaws 21 and rollers 12 close, the latter rotating to tension the knot. The frame then moves through the final 25 degrees, during which movement the sharpened outer edge of the curved end of member 16 severs the loop engaging the latter, when further rotation of the rollers 12 draws the severed end out of the knot-the severed end then being sucked into duct 10 through the opened jaws 21-and the knot being passed outwardly through the rollers 12. The knotter is incorporated in the travelling roll winder described in Specification 864,648. A yarn B of jute passes from a spool through a duct 28 to roll-forming means 22. The end of a yarn A passes from a full spool 24 between the rollers 12 and jaws 21 into the suction duct 10. On expiry of the spool carrying the yarn B, a member 30 closing a longitudinal slot 29 in duct 28 moves aside to allow yarn B to be drawn by the suction in duct 10 to pass through the slot and lie alongside yarn A. The knotting means comprises two shafts 36 and 68 driven at the same speed and in the same direction. Shaft 36 drives a shaft 39 via a friction clutch 38, a gear 40 on shaft 39 meshing with a gear 41 on shaft 18, carrying the knotting frame 14, to drive shaft 18 at twice the speed of shaft 39. A collar 60 on shaft 18 bears against a face cam 52 on shaft 39, whereby sliding movement is imparted to shaft 18 against the bias of a spring 62. Shaft 68 drives a shaft 72 through a friction clutch 70. A gear 102 on shaft 72 meshes with a gear 104 to drive one of the rollers 12. The other roller 12<SP>1</SP> is carried by an arm 105 pivoted at 106, and is biased towards roller 12 by a spring 107. A roller 108 on arm 105 co-operates with a face cam 109 on gear 102 to control the position of roller 12<SP>1</SP>. The jaws 21 comprise a fixed jaw 100 and a movable jaw 98 constituted by the end of an arm 94 carried by a pivoted shaft 96, to the other end of which is fixed an arm carrying a roller 88 spring-biased against a face cam 86 carried by shaft 72 and co-operating with cam 86 to control the position of jaw 98. In the rest position of the apparatus, an end 46 of a bell crank lever 42, pivoted at 44, engages a notch 48 in a collar 50 fixed to shaft 39 to hold the latter stationary. An end 76 of a bell crank lever 78, pivoted at 80, engages a notch 74 formed in the driven element of clutch 70 to hold shaft 72 stationary. The knotting operation is started when lever 42 is tripped by a moving part of the roll-winder to release shaft 39. When the latter has almost completed one revolution, a pin 82 on collar 50 engages on end 84 of lever 78 to withdraw end 76 from notch 74 to permit rotation of shaft 72. Immediately afterwards, end 46 of lever 42 enters a notch 56 in roller 50 to stop shaft 39. Rotation of shaft 72 closes rollers 12, 12<SP>1</SP> and jaws 21 to tighten the knot, a pin 58 rotating with shaft 72 then engaging end 54 of lever 42 to move the end 46 of the latter out of notch 56, when shaft 39 completes its rotation to effect the severing of the trapped loop, and is finally stopped when end 46 of lever 42 enters notch 48. Shaft 72 continues to rotate until end 76 of lever 78 enters notch 74. It is stated that the knotting operation can be completed in one revolution of the frame 14 by employing a swinging deflector, situated between the frame and the jaws 21, to engage the strand and to transfer it positively into the open frame. It is also stated that the frame may be permanently open.