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 as on the well-known ring spinning machine ,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.
• Such ring tilt is at least a major factor predisposing the formation of regions of patterning at certain radii of the package build, owing to the coincidence of adjacent coil loci.
• the incidence of these various regions of patterning, which patterning is to be avoided both from the technical point of view of package stability and yarn take-01f characteristics and from the point of view of appearance, can be calculated, e.g. by analogue computer, for any given process involving a drawtwisting wind-up; and hence it is possible to so programme the winding conditions that the regions of patterning which normally would occur shall be avoided.
• 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 mare than one spindle speed scrambling frequency shall be employed during the winding, the choice of frequencies and the programming of their application being effected so as to avoid any ratio of scrambling frequency to traverse frequency during the entire winding which is 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 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 in spindle speed is changed between at least two values during the winding, according to a programme of changes calculated 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 of programming may take various forms, the exact operation of which may depend on whether the traverse motion of the drawtwisting machine is of a constant-rate or a constant-time variety.
• Programming by a general purposes analogue computer is one such means, the computer serving automatically to control the number of changes in spindle speed cycle time occurring during the winding of a full package, by continuously measuring said traverse cycle by electronic means and controlling shifts from one frequency to another so as to avoid the critical ratios of such scrambling frequency to traverse frequency.
• 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 frusto-conical or cylindrical.
• the following details are given of a process for drawtwisting 70 denier 30 filament yarn of polyhexamethylene adipamide (nylon 66), at a draw ratio of 3.36 and a drawing speed of 2,300 feet/minute.
• the yarn was woundup by a ring spinning mechanism with the ring tilted to 3 to the horizontal; and the yarn package was wound with a long-to-short traverse build, constant traverse speed.
• 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.
• a 3-shift rapid variation in spindle speed was programmed on to the spindle drive mechanism by an analogue computer, of an amplitude of of the instant spindle speed, the rate of change of spindle speed (or scrambling frequency) being changed according to a 3-shift rapid variation programme so designed that the shifts in spindle speed occurred when the ratio of scrambling frequency to traverse frequency at one of the scrambling frequencies approached a ratio of small whole numbers, i.e. whole numbers either of which is less than 5.
• 100 denier 34 filament yarn of polyhexamethylene adipamide was wound up at 2646 feet/minute after being drawn on a drawtwisting machine.
• the yarn was wound-up by a ring spinning mechanism, with the ring tilted to 3 to the horizontal; and the yarn package was wound with a long-to-short traverse build, at a constant traverse speed of 23 inches/minute.
• the mean spindle speed was maintained constant at 6,850 r.p.m.; and this speed was varied -10% about the mean at two discrete frequencies, and a change was made from one to the other, at the lengths of traverse stroke as shown in the following table:
• the high value of 0.048 cycle/second was selected in order to place the 1:1 ratio of scrambling frequency to traverse frequency just outside the range of package build. Then, the lower frequency of 0.03 84 cycle/second was selected in order to avoid the occurrence of an undistributed patterned region near to the bobbin surface, where pressures are greatest within the package.
• the principle so far as amplitude is concerned, is to use the lowest amplitude consonant with the achieving of effective dispersion of the patterns; so that amplitudes greater than, say 15% will be unlikely to be needed or desirable.
• a method as in claim 1 including the step of electronically monitoring the traverse cycle to obtain a signal and wherein the frequency of the cyclical variation in spindle speed is switched in accordance with a function of said signal.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Winding Filamentary Materials (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=10407717

Family Applications (1)

Country Status (6)

Cited By (3)

Families Citing this family (1)

Citations (5)

• 1966
  • 1966-09-01 GB GB39115/66A patent/GB1198058A/en not_active Expired
• 1967
  • 1967-08-21 US US661770A patent/US3452533A/en not_active Expired - Lifetime
  • 1967-08-30 NL NL6711900A patent/NL6711900A/xx unknown
  • 1967-08-31 CH CH1219967A patent/CH468485A/de unknown
  • 1967-09-01 DE DE19671685868 patent/DE1685868A1/de active Pending
  • 1967-09-01 FR FR1558322D patent/FR1558322A/fr not_active Expired

Patent Citations (5)

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