The theme of this article is to discuss the productivity of an automatic winder. At first, the theoretical efficiency of machine77 is defined and then the theoretical numbers of drums p₀ to which one worker operates is defined.
R expressed as R=p₀·ν/ν_s was considered as an index of the productivity of winder, where V is the yarn speed and ν_s is the standard speed of yarn.
Winders are classified as the following five typical types :
(1) The winder operated by hand.
(2) The winder comprising more than fifty drums to which one knotting unit operates and it knots the yarns from a package and a new cop, but does not knot a broken yarn.
(3) The winder similar to type (2), but attached with an automatic cop feeding device and auto-doffing device.
(4) The winder comprising about ten drums to which one knotting unit operates and knots the broken ends when yarn breaks.
(5) The winder of which each drum is operated by each knotter and attached with the automatic cop feeding device.
η, p_s and R are shown as a function relating to the rate of yarn breakage α for each type of winder above mentioned. According to the increasing, the specific characteristics of η, p_s and R will vary. For instance, the values of the winder of the type (2) and (3) are good when α is less than 0.2, but when the value of α is 0.2 or more, they will decline in the bad condition. On the contrary, the winders of the types (4) and (5) maintain good condition, even when α is more than 0.2. It was ascertained that the automatic cop feeding device showed good efficiency.

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The purpose of this article is to consider the behavior and physical properties of the sewing thread during sewing motion in relation to the sewability.
The auther examined the relation between the Sewability and the statical properties of some sewing thread and found no relation between them.
To investigate the reason, the dynamic behavior and the change of physical properties of a sewing thread during Sewing motion is considered with some experiments.
As the results, it is cleared that the dynamic hebavior of a sewing thread are characterized by the condition of high speed extension under high temperature.
And initial modulus, thoughness index, and breaking stress etc., under such conditions are shown, and their influenced on the sewability are considered.

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