Abstract: A holder includes a stay lock member capable of locking a vertical movement of a headrest stay at an appropriate vertical position by engaging with an engagement portion of the headrest stay. The stay lock member includes a flexible holder having a nail portion engageable with the engagement portion along a circumferential direction of the headrest stay as the flexible holder moves in a lower direction and separable from the engagement portion as the flexible holder moves in an upper direction, and an operation member capable of moving the flexible holder in any of the upper and lower directions.

Abstract: Frame structure for housing panel plates such as printed circuit boards. This structure is capable of housing panel plates having varying width, and consists of a top plate that is spaced from a bottom plate fixed thereto by means of support columns. The structure also has an immovable side board and a movable side board between the top and bottom plates. Each of the opposing side boards has a plurality of lateral grooves for housing the plates. The movable side board is easily movable while it is kept parallel to the immovable side board.

Abstract: A method for reducing the caking property of coal, by contacting coal with sulfur dioxide in an amount at least 0.5 times the amount of the coal on a weight basis, at a temperature of at least 120.degree. C. under a pressure of at least 10 Kg/cm.sup.2, and separating the treated coal from the sulfur dioxide, whereby to reduce the caking property of the coal and to render the coal more easily pulverizable.