Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01H—SPINNING OR TWISTING
  • D01H1/00—Spinning or twisting machines in which the product is wound-up continuously
  • D01H1/14—Details
  • D01H1/20—Driving or stopping arrangements
  • D01H1/28—Driving or stopping arrangements for two or more machine elements possessing different characteristics but in operative association
  • D01H1/30—Driving or stopping arrangements for two or more machine elements possessing different characteristics but in operative association with two or more speeds; with variable-speed arrangements
  • D01H1/305—Speed control of the spindles in response to the displacements of the ring rail

Definitions

• the invention concerns improvements in or relating to the over-end winding of yarn.
• Over-end winding of yarn is practised when it is desired to impart a twist to the yarn by the act of winding.
• a drawtwister is essentially a downtwister in which are incorporated roll mechanisms for drawing undrawn yarn.
• roll mechanisms consist of nip rolls rotated at a given speed acting as feed rolls; and a draw roll and separator roll combination, the former roll of which is rotated at the required higher speed to effect the drawing action on the filaments in question.
• the drawn filaments proceed in a generally downward direction to a thread guide positioned axially, or nearaxially, of the spindle of a ring and traveller ring spinning mechanism.
• This thread guide is sometimes known as the balloon guide, as the yarn is ballooned beneath it by virtue of the rotation of the traveller around the ring.
• the filaments are then wound up on a bobbin mounted on the rotating spindle, by passage around the traveller which is itself rotated around the ring and by reciprocation of the ring, in its rail, tray or other carrier, in the axial direction of the spindle according to the builder motion required for the particular yarn package to be wound on the bobbin.
• An alternative, or concomitant, approach to the reduction or avoidance of patterning, whether from natural or self-induced causes, consists in the rapid variation of one or more of the winding parameters, to bring about a scrambling of the winding conditions throughout the winding, in order continuously to modify the wave-form of the coils of yarn as laid on to the take-up package.
• the spindle speed may be rapidly varied, by say, 10% about the mean value desired; and this rapid variation or scrambling, of the spindle speed will serve to break up patterning when it occurs at the calculable winding conditions during the formation of the package. Variation takes place in a cyclical manner about the mean spindle speed; and the number of cycles occurring in unit time is termed herein the frequency.
• the present invention is based on the proposition that it is necessary to control the spindle speed scrambling frequency during the winding so as to avoid the above-referred to whole number ratios, such control of scrambling frequency being achieved by monitoring it by, and directly in relation to, the traverse frequency, so as preferably to lead to a constant ratio of scrambling frequency to traverse frequency during the entire winding, such ratio not being a ratio of small whole numbers leading of itself to patterning.
• the invention comprises a method of winding yarn by over-end winding on to a yarn package with the aid of a rotating spindle and a traversing means, wherein the speed of rotation of the spindle is varied cyclically about mean values thereof selected to be operative at given times during the winding of the package, or about a mean such value maintained constant throughout the winding, and wherein the frequency of such cyclical variation is monitored by, and is varied directly in relation to, the traversing frequency in such manner as to avoid any value of the ratio of said frequency to the traversing frequency ever being one consisting of small whole numbers (i.e. either of which is less than 5) such as would of itself lead to patterning occurring at given radii of the package during winding.
• the means for monitoring the scrambling frequency by and in relation to the traverse frequency and for controlling it in consequence thereof according to a desired programme may take any mechanical or electronic form convenient for the purpose and which is capable of sensing traverse frequency on a continuous basis and generating a scrambling frequency therefrom at a fixed ratio of frequencies, or at predetermined values of such ratio according to a desired programme.
• Such a means may be a general purpose analogue computer, containing amplifiers, relays and comparator circuits and fed with signals identifying the instants in time of the bottom and top reversals of the drawtwister traverse motion.
• the output represents spindle speed containing the desired scrambling component, and is fed to the input of a speed-controlling servo-motor driving the spindles on the machine.
• the specific method of continuously controlling spindle speed cycle time according to the invention may be combined with other expedients for the avoidance or reduction of patterning in over-end wound package.
• the invention may be combined with other more radical programming of the spindle speed, e.g. whereby regions of patterning due to ring-tilt may be avoided. Equally, the invention may be combined with controlled or random variations in traveller speed and with yarn delivery speed.
• the invention is applicable to the winding of yarn packages on all kinds of bobbin or tube, it will be understood that the particular programme to be selected will be affected by the shape of the tube, e.g. as to whether it is frusta-conical or cylindrical.
• the following details are given of a process for drawtwisting 100 denier 30 filament yarn of polyhexamethylene adipamide (nylon 6.6), at a draw ratio of 3.36 and a drawing speed of 2.646 feet/minute.
• the yarn was wound-up by a ringspinning mechanism with the ring tilted to 3 to the horizontal; and the yarn package was wound with a long-toshort traverse build, constant traverse speed of 23 inches/ minute.
• the spindle speed was programmed so as to reduce from an initial 9.750 r.p.m. to a final speed of 7,350 r.p.m.
• the yarn was produced and wound similarly to the above example, save that the spindle speed was scrambled i5% about the instant mean value, and the ratio of scrambling frequency to traverse frequency was 7.1.
• the principle so far as amplitude is concerned, is to use the lowest amplitude consonant with the achieveing of eifective dispersion of the patterns; so that amplitudes greater than, say, 15% will be unlikely to be needed or desirable.
• a method of claim 1 wherein said monitoring step is effected by electronically sensing the instants in time of the top and bottom reversals of the traversing means to obtain a signal and wherein the frequency of spindle speed cycling is varied in accordance with a function of said signal.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Winding Filamentary Materials (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=26259758

Family Applications (1)

Country Status (6)

Cited By (3)

Families Citing this family (2)

Citations (5)

• 1966
  • 1966-09-01 GB GB39114/66A patent/GB1198057A/en not_active Expired
• 1967
  • 1967-08-21 US US661771A patent/US3452534A/en not_active Expired - Lifetime
  • 1967-08-30 NL NL6711902A patent/NL6711902A/xx unknown
  • 1967-08-31 CH CH1220067A patent/CH466106A/de unknown
  • 1967-09-01 FR FR1558321D patent/FR1558321A/fr not_active Expired
  • 1967-09-01 DE DE19671685869 patent/DE1685869A1/de active Pending

Patent Citations (5)

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