Patent GB-891514-A (GB)
Title: Method and apparatus for winding yarn at constant linear speed
IPC: B65H59/38
Filed: 1960-03-09
Abstract: 891,514. Winding yarns. LEESONA CORPORATION. March 9, 1960 [March 17, 1959; July 1, 1959], No. 8271/60. Class 120(2) [Also in Group XXXVII] In winding yarns, the spindle-speed is continuously changed in response to activation effected by the change in diameter of the package, and is further changed in response to a separate actuation by tension changes in the yarn. in Fig. 4, a spindle 17<SP>1</SP> pivots at 38<SP>1</SP> relatively to a traverseguide 28<SP>1</SP> as the package grows and rocks a cam 41 to move a pivoted lever 40 secured at 42 to a belt 69 to move a contact 63 to gradually decrease the supply to a D.C. motor 16<SP>1</SP> driving the spindle. Also a bight of yarn varying according to the tension varies the position of a rod 70<SP>1</SP> to raise and lower a core 27 in a coil 24 to vary the current to the motor in a sense to keep the size of the bight constant. The control circuit for the motor is shown in Fig. 5. Contact 63 moves from right to left as winding proceeds along a potentiometer 61 in series with a setting-potentiometer 244 and coil 24 is in series with a transformer secondary and primary windings 232 and 236. Hence the output of secondary winding 242 to which is added that of secondary 240 rectified at 248 and smoothed by capacitor 250 is transmitted to contact 63 which thus receives a signal which is variable according to the position of core 27 in coil 24 which it transmits to the phase-shifted grid of a thyratron 220 controlling motor 16<SP>1</SP>. A starting switch 217 is connected to a switch 226 so that when the former is closed the latter opens and vice versa: when 217 is closed 226 being open a capacitor 230 which is charged to the voltage of contact 63 discharges through a resistor 228. At first the voltage at 221 is zero because the voltages on 63 and 230 are of opposite sign; as 230 continues to discharge, the voltage at 221 which is applied to grid 223 rises until thyratron 223 starts to fire so that the motor starts gradually. Capacitor 224, which with 226 open becomes charged to the value of the control signal, serves to cushion changes caused by rapid movement of core 27. The collapse of the motor shunt field in a coil 212 when switch 217 is opened, contact 63 now being at the extreme left of the potentiometer, induces a negative voltage across a resistance 214, which is applied to grid 223 to phase off thyratron 220. In other forms, movement of the spindle correspondingly moves a resistance element of a rheostat or the coil of an autotransformer relative to a contact and changes on the tension cause the contact to move relatively to the element or to the coil: in each case the position of the contact varies the voltage across the motor 16<SP>1</SP>. When an autotransformer is used the motor may be controlled by the circuit of Fig. 3 where the output of autotransformer 15 as determined by the position of contact 155, rectified at 142 and smoothed at 143 and 144 is applied to the centre tapping of transformer secondary winding 126 and to one end of the motor-field winding 164. Accordingly a variable voltage is applied by windings 126 to phase-shifted grids of tubes 130, 131 which fire when a selected grid-voltage is attained and thereby establish the voltage applied to armature 160; also a variable voltage is applied by winding 127 to field winding 164 through a rectifier, resistance and capacitor network. Specification 787,129 is referred to.