GB891321A - Improvements in or relating to automatic draft regulating devices for the drawing sections of textile spinning machines or preparatory machines - Google Patents

Abstract

891,321. Drafting-mechanism. VENNER, H. A. L. (Spinnereimaschinenbau Karl-Marx- Stadt VEB). July 21, 1959, No. 25007/59. Class 120(2) [Also in Group XXXVIII] Means for automatically regulating the draft according to variations in sliver-thickness and delaying the regulation until that portion of the sliver giving rise to it reaches the drafting field, comprises three potentiometers, two 12, 13 in series and one, 14, in parallel with them, 12, 13 forming one side and 14 the other of a switching bridge for a reversible electric motor 16 which initiates the regulation: the potentiometer 12 is adjustable by one of two sensing-rollers 5, 6, while 13 is manually adjustable according to the basic speed of the driving roller 5 of the sensing- pair suitably to delay the effect of the regulation, and is coupled to a voltage adjuster 19 for the motor, the latter also constituting the adjusting means for the potentiometer 14. Displacement of roller 6 rotates a gear 11 through a quadrant 10 and a pivoted lever 8: the gear 11 adjusts the setting of potentiometer 12 and if the bridge is unbalanced current flows through a polarized relay 15 to close one of two contact-pairs governing motor 16. The arm of potentiometer 13 is coupled to the arm of a votage-adjuster 19 which, through a rectifier 24, feeds motor 16 which is coupled to the arm of potentiometer 14 to move it until there is equilibrium in the bridge to cut-off current to the motor. The latter also acts to vary the output of one of two hydrogenerators 36, 37, the latter of which supplies through a valve 39 two hydromotors 26, 25 coupled respectively to the back and front rollers 2, 1 of the drafting -frame, the latter coupling being through lower roller 5 of the sensing-pair and a chain 35. Valve 39 supplies part of the driving fluid to motor 26 and part to 25. The return line 48 from motor 26 is the output line of generator 36, the output of which accordingly brakes motor 26 to a greater or less degree. If motor 26 decelerates, motor 25 accelerates on account of valve 39. A safety valve 49 and a pressure-holding valve 53 are provided while a pump relieves hydromotor 37 from having to draw up the driving-fluid. The arrangement can be adapted to drive either the front or the back rollers.