|Budget Amount *help
¥1,300,000 (Direct Cost : ¥1,300,000)
Fiscal Year 1991 : ¥100,000 (Direct Cost : ¥100,000)
Fiscal Year 1990 : ¥1,200,000 (Direct Cost : ¥1,200,000)
A new testing system was constructed to evaluate the sewability of threads during machine sewing. A high-speed and constant-load cyclic test for sewing threads is desired from a point of view of sewing. The testing equipment utilizes the motion of needle bar and cyclic loading is given to a specimen. Between two clamps of the test machine, there is a thread absorber which compensates the unrecovered (permanent) strain to operate constant-load cyclic test. The thread absorber has a servomotor which is controlled by personal computer. This method enables constant-load cyclic test under high-speed conditions although it is necessary to determine the control data by trial and error. In actual experiment, the testing equipment worked successfully.
Ufirecovered strain and work of samples (sewing threads) in every cycle were obtained from the test data using computer. The unrecovered strain was increased with cyclic loading and was saturated soori. On tlie other hand, the work taken from threa
d stretching process became a little smaller with(, Yclic loading but the work in the recovering process maintained some constant level. There was a linear relationship between the work in the recovering process and the maximum tension held constant in cyclic loading.
The contraction of seams sewed by a lockstitch machine was measured. The contraction (i. e. seam ptickeritig) is related with the work in the recovering process obtained from the thread test described above. Next, the motion of check spring was observed photographically. It was shown that the motion of spring was roughly explainable using the elongational data of sewing threads obtained from the test. There was little relation between the elongational properties of threads and loop configurations of needle threads.