| 摘要 |
FIELD: printing.SUBSTANCE: invention is a portable drawing tool of roller type for drawing parallel lines of different orientations and circles on the basis of a number of holes. The roller ruler comprises a housing bearing a plate and a roller support. The plate is made of a transparent material, has a straight front edge and at least two scales - linear and arc. For making circles of various radii the plate is equipped with a means comprising the center of rotation with a working element in the form of pressure axis of rotation for contact with a sheet of paper. Parallel to the front edge of the plate there is a linear series with a constant pitch of through holes for the writing tip. The housing has a cavity open from below. The roller support is placed in the housing cavity and is designed in the form of a cylindrical shaft stepped by diameter. The geometrical axis of the shaft is oriented parallel to the front edge of the plate. The shaft is connected to the side walls of the housing with the ability to rotate and has two equal roller stages with the friction surface, located at its ends, which partly pass beyond the lower surface of the plate. The ruler has a mechanism of exclusion the working contact with paper of roller stages of the shaft, and its center of rotation is made with the ability of fixed movement in a direction of a linear series of holes within at least their step.EFFECT: expanding the range of circles drawn.21 cl, 26 dwg |
