Patent GB-932289-A (GB)
Title: A mechanism for uniting two threads
Inventor: TROST WAYNE CLIFFORD
IPC: B65H69/04
Filed: 1959-09-04
Abstract: 932,289. Knot-tying devices. BARKERCOLMAN CO. Sept. 4, 1959, No. 30284/59. Class 74 (2). A device for tying a weaver's knot comprises a knotting bill projecting transversely from a rotary shaft and having a pair of thread-cutting and gripping jaws, means for supporting one thread in a substantially straight line extending transversely of said shaft and within and adjacent the heel of the bill, means for supporting the other thread alongside the first thread and crossing the latter at points spaced from said heel with the intervening portion lying adjacent the outer side of the heel, means for shifting the threads laterally to position the second thread within the open jaws of the bill, means for cutting the first thread, and means for stripping the knot from the bill. The device is incorporated in a machine in which a thread running at high speed therethrough is knotted, on breakage, to a reserve thread positioned adjacent thereto. A knotting bill 196, having a blade pivoted between a pair of spaced-apart blades, projects transversely from a horizontal shaft (not shown) and normally lies in a horizontal plane. A running thread 20 passes vertically in succession through the open jaws 200b, 200d of a lower clamp, a notch 249 in a fixed plate 248, a notch 263 in a positioning finger 202 pivoted at 257, within the heel of the knotting bill, a notch 244 in a fixed plate 231, and finally through the open jaws 230a, 234 of an upper clamp. The upper end of a stationary reserve thread 21 passes in succession through a notch 271 in plate 248, a notch 264 in finger 202, across thread 20 at 265, around the outside of the knotting bill heel, across thread 20 at 266, and through a notch 270 in plate 231. Jaws 200d and 234 are carried by a yoke 235 pivoted at 232. A stationary cutter blade 247 is aligned with one edge of notch 249 and a co-operating blade 250 is pivoted at 251 to blade 247. A blade 216 carries a gear 219 meshing with a pinion 220 on shaft 204. A torsion spring 215 has its lower end rigid with shaft 216 and its upper end rigid with a pinion 217 which is journalled on shaft 216 and meshes with a gear 218 rigid with a shaft 24. Normally, shaft 216 is held stationary and shaft 24 is rotated sufficiently to stress spring 215. It is so arranged that breakage of the running thread 20 results in the release of shaft 216, whereby spring 215 turns the latter through one revolution during which the knotting bill rotates four times, in the first of which it ties the threads 20 and 21 together. It is stated that the knot is formed in about from 0.005 to 0.015 of a second. Shaft 216 is normally held stationary by the engagement of an arm 233 thereon with an abutment 222 on a latch 221 pivoted at 224. Latch 221 is held stationary by engagement with an abutment 225 on a latch 226. The latter is pivoted at 227 and is biased by a spring 228 into engagement with a cam notch 229 on a spindle 150. It is arranged that the latter rotates when thread 20 breaks, whereby latch 226 is turned to release latch 221 and the latter swings to engage a stop 291 while an arm 292 thereon is held by a spring detent 293. Arm 223 rotates once to displace and then abut a spring stop. One arm of a bell-crank lever 300 pivoted at 302 carries lugs 303 which straddle spring 293, and the other arm carries a lug 298 which normally lies in one of a series of notches 296 formed in a circular flange 297 rigid with shaft 24. One arm of a bell-crank lever 301, also pivoted at 302, has a pin-and-slot connection 304 with an arm 305 on latch 221, and the other arm has a lug 299 also lying in the notch 296. Initial movement of shaft 24, when the latter is turned clockwise to wind spring 215, will engage an edge of the notch 296 with lug 298 for turning lever 300, when lugs 303 will move detent 293 to release latch 221. Said edge subsequently engages lug 299, when lever 301 will turn latch 221 counterclockwise past abutment 225. Further turning of shaft 24, by stressing spring 215, will turn arm 223 to engage abutment 222, whereby latch 221 is turned to engage abutment 225. When shaft 216 commences to rotate, upon breakage of thread 20, a linkage connecting a cam disc 239 thereon with yoke 235 turns the latter to close the upper and lower clamps on thread 20, whereby the V above crossing 226 is moved into alignment with the tip of bill 196. Subsequently, a linkage associated with a cam disc 259 on shaft 216 pivots the positioning finger 202 to shift thread 20 within the cutter blades 247 and 250, and to shift thread 21 for engagement within the opened jaws of the knotting bill. On further rotation of shaft 216, a further linkage between cam disc 239 and blade 250 swings the latter to sever thread 20. Thread 21 is severed and held by the closed jaws of the knotting bill, and a stripper finger 203a, rigid with shaft 216, finally tightens the knot and strips the latter from the bill.