The Shifting of the Lining on the Rayon Velvet by a Plate Pressure Assuming that the Presser Foot Presses the Layers

Abstract

This experiment is carried out on the model of the phenomenon which takes place when a cuprammo nium linings on the piles of a rayon velvet is pressed down by the presser foot during the sewing operation. The results obtained are as follows.
(1) Assuming that the lining on piles under pressure is shifted by the tips of the piles, the shift of the lining parallel to the horizontal plane are measured in the case of two kinds of toothbrushes, one of which has the same height of piles and the other has two height levels of piles. In the latter case, the shift of the lining finally becomes greater than the height of the longer piles.
(2) The shift of the lining on the velvet pressed by a plate can approximately be given by the shift of the latter case in (1).
(3) All the piles of velvet lean in a certain limited direction by pressing and the coefficient of static friction of the velvet is minimum in the pile direction and is maximum in the opposite direction.
(4) With increasing the pressure, the coefficient of static friction of the velvet in the pile direction decreases, but the one in the opposite direction increases with increasing the pressure beyond the critical value.
As above mentioned, the lining on the piles of the velvet is shifted into a pile direction by tips of piles when the pressure of a plate is applied. If the pressure exceeds the critical value, the larger difference in the coefficient of static friction is recognized between the pile direction and the opposite direction. Therefore, it is almost impossible to prevent the shift of the lining by hand. So, this phenomenon is referred to as “Green Bristle Glass (Setaria Viridis) Effect” by the authors.