Abstract: Apparatus and method are described for developing indentation defined characters formed within pixel matrices having a generally arcuate configuration. The row and column matrices which are formed by the method are characterized in having arcuate rows which are regularly spaced radially from a marker axis. The column components of the pixel matrices are regularly angularly spaced radii emanating from the same marking axis. A rotational marker head is provided carrying marker pin assemblies which are oriented at regular radial angular spacings and in progressively incrementing regular radial distances from the marker axis. As the marker head assembly is rotated, the marker pin assemblies are actuated to form the arcuate character string. The apparatus and method permits the marking of significant character string information on restricted surfaces such as the face of gears and the like.

Abstract: Apparatus for simultaneously forming one or more lines of multi-character messages on the surface of solid material which employs an array of marker pins which are moved by a carriage along a singular plane locus of movement defining a sequence of rows corresponding with a pixel matrix. The locus includes a retrace feature for each row or transverse movement which enhances the quality of character formation. An actuator assembly develops the locus of movement and, in turn, is driven by facing cam wheels which, in turn, are powered from an electric motor. A manifold which receives pneumatic pulses from arrays of conduits is coupled to the carriage and a marker head assembly, in turn, is removably coupled to the manifold. An array of solenoid actuated valves is coupled to the tubing arrays and to a pneumatic source which may be remotely positioned from the manifold.