Abstract: A self-propelled drawing device is driven by two independent wheels whose axes are fixed, and has a writing tip which marks the drawing medium at a point which is not on the imaginary line joining the points of contact of the wheels with the drawing medium. The drawing device is connected to a stationary control device by flexible conductors in the form of a ribbon whose width lies in a vertical plane. Instead of a drawing device, the device can be arranged as a tracing device with counters on the wheels and a tracing tip instead of the writing tip.

Abstract: A chart recorder is described in which the writing head is rotatable by a motor to position any one of several writing tips over the paper. The motor is mounted on the same carriage as the writing head for movement relative to the paper.