Abstract: Electrographic apparatus includes a transducer pad having a flexible membrane mounted over a base member with facing surfaces of the membrane and base member being electrically conductive and having electrical voltages applied thereto whereby to provide electrical signals representing the coordinates of a location at which pressure is applied to the flexible membrane locally by a pen or stylus, wherein in order to maintain an appropriate tension in the flexible membrane, the membrane is attached to and mounted on an outwardly tensioned rectangular frame member. The frame member may comprise separate frame elements and spring members forcing the elements away from one another. Alternatively, the frame member may be resilient and be inwardly compressed during the attaching thereto of the flexible membrane whereby the inherent resilience of the frame member subsequently tensions the flexible membrane.

Abstract: A handwriting recognition device comprises a transducer surface responsive to a pen positioned thereon for representing the coordinate position of the pen as an electrical signal, and data processing means for recognizing a handwriting effected with the pen, the data processing means including a microprocessor based control controlling a read/write memory, a non-volatile read-only memory storing a handwriting recognition routine to store recognized handwriting in the read/write memory, and an interface communicating to a host computer system a representation of the recognized character. A visual display may be provided coupled to a display interface and an input information for receiving verified recognized handwriting communicated from the host computer system.

Abstract: A guided carriage assembly for photodrafting equipment comprises a carriage and guide means for the carriage wherein the guide means comprises three parallel rails presenting accurately ground horizontally extending straight edges, one of the outermost straight edges lying in a horizontal plane and the other outermost edge and the intermediate edge being inclined to the horizontal in opposite directions, and the carriage assembly comprises two pairs of aligned rollers bearing on the inclined edges and a single roller bearing on the horizontal edge. The arrangement is such that the precision of movement of the carriage is governed substantially entirely by the straightness of the edges. A preferred embodiment comprises two such assemblies one mounted atop the other with the rails of the one extending orthogonally to those of the other whereby to provide an X-Y table.

Abstract: Projection apparatus for photodrafting equipment in which an exposure control disc is rotated to vary the intensity of the projected light during exposure of a line is provided with a region which on rotation of the disc effects progressive decrease in the intensity, that region being followed by an aperture or clear region and that in turn being followed by an opaque region. Thus the disc can be rotated in one direction to progressively reduce the intensity, then produce a brief flash at maximum intensity, and then shut off the projected light completely. The preferred form of the exposure control disc, believed novel in itself, comprises a tapered slot movable lengthwise through the optical path of the apparatus to selectively restrict the exit pupil thereof.

Abstract: Electrographic apparatus, that is apparatus for obtaining electrical signals related to the movement of a point, such as a pen or stylus, over a pressure sensitive surface. The apparatus comprises a hand-supporting plate movable relative to the pressure sensitive surface to provide a convenient hand-rest during writing or drawing without the hand touching the pressure sensitive surface.

Abstract: Photodrafting equipment which can be operated alternatively in first and second modes. In the first mode, the equipment can expose continuous lines in conventional manner. In the second mode, the equipment can expose a plurality of discrete areas or "pads" without interruption of carriage movement. To this end the projection apparatus of the equipment comprises a relatively low intensity light source for exposing the lines, a relatively high intensity flash light source for exposing the pads, and a rotatable reflecting prism to select one or the other of the light sources in accordance with the mode of operation.

Abstract: Electrographic apparatus, that is apparatus for obtaining electrical signals related to the movement of a point, such as a pen or stylus, over a pressure sensitive surface, and a method of producing an electrode surface for such apparatus. The pressure sensitive surface is formed by the upper surface of a taut flexible membrane. Two generally parallel electrode surfaces are formed by electrically conductive coatings on the lower surface of the flexible membrane and on an upper surface of a backing member so that pressure applied to the pressure sensitive surface locally interconnects the electrode surfaces. In use, voltages are applied orthogonally to the respective electrode surfaces so that the potentials developed at points on the surfaces correspond to the X and Y coordinates of those points.