Drawing board assembly having angle scale device

摘要

A drawing board assembly includes a board having two tracks and two slide bases are movably received in the tracks. A ruler is connected between the two slide bases and a frame is connected to the ruler. The frame has a groove in which a slide member is movably received. A protractor is connected to the slide member and a guide ruler is pivotally connected to the protractor. A bolt extends through the guide ruler and the protractor. A positioning knob is connected to the bolt so that when the bolt is loosened, the guide ruler is pivoted.