| 摘要 |
1,135,752. Drafting - appartus; measuring sliver. T.M.M. (RESEARCH) Ltd. 4 July, 1966 [20 July, 1965], No. 30820/65. Headings DID and D1F [Also in Division G3] To reduce variations from standard in the mass per unit length in drafted material, drafting apparatus comprises means for measuring the mass per unit length of material being fed to a main drafting system, and control means responsive to deviations so measured to vary the draft in a control drafting system which acts on the material before it reaches the measuring station. Slivers are fed from cans 13 by driven feed-rollers over a table 14 and travel in turn around guides 15, through a control drafting system 16, through a converging guide 19, measuring rollers 21, 22, below and above spreading- guides 23 respectively to be delivered by rollers 26 to a main drafting system. The measuring- rollers comprise a vertically-displaceable disc 21 cooperating with a fixed grooved roller 22 driven at constant speed. The displaceable roller is coupled to a transducer which generates a signal related in phase-angle to the direction in which the disc is displaced. The signal from the transducer is amplified at 28 and fed to a servo-motor 29 supplying a variable input at 31 to a speed-changer 32. This also receives a constant speed input at 33 from the delivery rollers 26 and the variable output from it is delivered at 38 to the front rollers 17 of the control system 16 of which the back rollers are driven at constant speed from the rollers 26. The draft produced at 16 is normally between 1 and 2; when sliver of reduced diameter appears at the measuring-station, the disc 22 falls so that the phase angle of the transducer signal is zero, and the front rollers 17 are speeded to reduce the draft at 16. When the disc rises, the phase angle changes through 180‹ to slow the rollers 17 correspondingly and to increase the draft. The device will also compensate for the absence of a sliver or the presence of an additional sliver during piecing. Instead of a servo-motor clutches may be employed as in Specification 941405 to vary the draft of the control drafting-system. |
