Pair of compasses for drawing arcs or circles

摘要

The drawing compasses have two pivoted branches, one with a point about which the compasses pivot, and the other with a holder for a pencil or lead which traces the arc or circle. The pivot point has a rotatable rounded tip (7) on the end of a spindle (8) set in a fixed body (9). The tip is covered partly or completely with a non-slip surface which is placed at the centre of the arc or circle to be drawn.Each branch has a mechanism which ensures that both its points lie perpendicular to the surface on which the drawing is made.