Abstract: A universal digital converter for drafting machines operable to sense and instantly display numerically on one of the machine scales incremental linear or angular movements thereof. A sensor mounted on the scale has a wheel in rolling contact with the drafting surface and generates signals proportional to the net distance moved in a selected direction and these signals are processed electronically to represent the distance travelled in any desired preselected scale ratio. The sensor is quickly positionable to measure movements of either the horizontal or vertical scales, as well as angular movements of the protractor ring of a standard drafting machine.

Abstract: A multipurpose drafting and measuring instrument having an upright marking device mounted on a base or main frame readily maneuverable over sheet material. Mounted on the instrument main frame are one or more signal generators each having a roller in frictional driving contact with the sheet material and with their axes normal to one another and to a respective peripheral edge of the instrument base. The signal generators are connected to respective digital display panels each having a manually settable scale changer. Any of a variety of marking devices can be substituted for one another. The instrument includes various readily attached accessories for utilizing the instrument as an Y, X digitizer, a protractor, a planimeter, and both as a linear and a circular scale graduator.