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Volume 18, Issue 2
Displaying 1-3 of 3 articles from this issue
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Part 1: Deriving the Equation of Motion for WeftMinoru Uno1972 Volume 18 Issue 2 Pages 37-44
Published: 1972
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSFor scrutinizing the motion of weft gushed out and propelled by air stream, the physical (especially aerodynamic) properties of air jet and weft yarns are examined. An equation of motion for weft on an air jet loom is then derived, leading to the numerical solutions in several cases. The followings are some of the results: 1) The axial velocity of air jet is approximated fairly well by the following formula excepting the core region: V=BV0; /(x-A) where A and B are constants, V0; the initial jet velocity, x the axial distance from the nozzle exit to any point. 2) The coefficient of friction of spun yarns in air stream is approximated by Cf; =0.02+1/(V'+2) where V' is the relative air velocity to the yarn in m/sec. 3) In case where an air jet loom utilizes a measuring drum for yarn reserving, the drag due to yarn ballooning is as large as the air thrust. In order to minimize this harmful effect, a suitable cover should be set around the drum. 4) As the time necessary for the yarn to travel for some given distance is rather long in the region where the starting acceleration is not large, the initial jet velocity V0; should be quite large, say over 200m/sec.View full abstractDownload PDF (699K) -
Part 3: Measurements of the Hand of Various FabricsTatsuki Matsuo, Takashi Harada, Minoru Saito1972 Volume 18 Issue 2 Pages 45-54
Published: 1972
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSMethods for measuring the hand were given in the previous article (Part 2).
In this article 63 kinds of fabrics are measured by these methods. They consist of 15 worsted woven fabrics, 21 cotton-type spun-yarn woven fabrics, 9 textured yarn woven fabrics, 6 filament woven fabrics and 9 textured yarn circular knitted fabrics.
The hand of the fabrics is analyzed from the data obtained by measuring the main factors which govern their hand, and is summarized in Figs. 13 and 14.
The mutual relations among 9 factors of the hand are statistically analyzed and summarized in Table 2.
The factors, 'weight', 'thickness', and 'bending rigidity', are closely correlated to one another.
The factors, 'compression rigidity', 'friction coefficient', 'bending recovery' and 'rigidity of elongation', are almost independent of other factors.View full abstractDownload PDF (1125K) -
Yoshiki Yanagawa, Sueo Kawabata, Hiromichi Kawai1972 Volume 18 Issue 2 Pages 55-63
Published: 1972
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSIn previous paper, a biaxial tensile deformation theory was developed of a plain tricot fabric, a fundamental type for all two-bar tricot fabrics, .
In the present paper, this theory is expanded and more generalized to calculate the properties of two-bar tricot fabrics. The structure of the model proposed for the plain tricot fabric is modified to make it adaptable to more complicated structure.
When the number of wale spacings crossed by underlapping becomes large or when spun yarn is used, the original theory becomes more error-prone. To make the theory more precise, the compressive property of yarn should be introduced for calculation in stretching-effective region. In the new theory, a simple model where yarn is wound around a cylinder is used for the structure of the crossover region.
Finally, some theoretical calculations have been done for various factors such as the tensile and the frictional properties of yarn, structural constants, and the number of wale spacings crossed by underlapping.View full abstractDownload PDF (924K)
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