Abstract: A vernier device of the digital display type for a universal parallel ruler is disclosed comprising a slit protractor having slits arranged at the same visually readable protractor and a intervals as those intervals for the protractor graduations, the slit protractor being provided on one of a stationary portion and a rotatable portion of a scale operating head. A slit vernier protractor having slits at other intervals for vernier graduations is provided, the slit vernier protractor being provided on the other of the two portions of the operating head. An encoder consisting of photoconductive elements and corresponding light-emitting elements is provided with the slit protractor graduations and the slit vernier graduations interposed therebetween wherein a fine vernier angle is digitally displayed for reading on the basis of a signal representing a coincidence between a slit vernier graduation and a corresponding slit protractor graduation.

Abstract: A universal parallel ruler is disclosed. It is an arm-type ruler and includes a first base attached to a drawing board, a first arm attached to the first base, a second base attached to the opposite end of the first arm, a second arm attached on one end to the second base, and a third base attached to the opposite end of the second arm. The third base includes a lead having an x-scale and y-scale attached thereto. The scales define an (x,y) coordinate system. When the x and y scales are horizontal and vertical, respectively, a point (X,Y) may be selected on a set of (x,y) coordinate axes defined by the scales. If the scales are tilted by .theta. degrees, the position of the point (X,Y) may be determined along a new set of coordinate axes defined by the tilt angle .theta. of the scales and may be identified by a new coordinate point (x,y) relative to the new coordinate axes as follows:X=L.sub.1 cos .theta..sub.1 +L.sub.2 cos .theta..sub.2Y=L.sub.1 sin .theta..sub.1 +L.sub.2 sin .theta..sub.2x=X cos .theta.

Abstract: A universal parallel ruler is disclosed. A desired angle of rotation of a preset member relative to a base line is selected. This angle of rotation is introduced into the ruler via an input station mounted on the ruler. The desired angle of rotation of the preset member is displayed on a display and an input signal representative of this desired angle of rotation is input to a comparator. The preset member is rotated. A detector detects the actual angular position of the preset member relative to the base line and it introduces another input signal to the comparator representative of the actual position of the preset member relative to the base line.

Abstract: A universal parallel ruler is disclosed. The head of the ruler includes preset stoppers which are adjustably positioned according the three axes of the three-dimensional drawing. There are three stoppers. One is stationary, and two are adjustable. The scale can be selectively set to the basic three axes by locking engagement with the preset stoppers. The stationary stopper corresponds to the vertical axis Y whereas the adjustable stoppers may be angularly set and correspond to the remaining (X and Y) axes. A locking piece may be engaged with or disengaged from the preset stoppers so that the scales may be engaged with the preset stoppers after the stoppers have been angularly set as desired. Also, the three preset stoppers may be fixably or adjustably mounted on the ruler's protractor so that the three axes of the three-dimensional drawing may be independently set.

Abstract: A universal parallel ruler is disclosed. The ruler includes two digital read-out displays for displaying the displacement of the ruler in the x and y directions. In displaying the position of the ruler along the directions, the ruler compensates for the displacement of the movable rail relative to the stationary rail. It further compensates for the displacement of the head relative to the movable rail and for the x and y scales relative to the head. A reset is provided by which the position of the x and y reference axes may be changed. In addition, the ruler may be set to operate in a reduced or multiplied scale, and the digital display will, in either case, display the actual reduced/increased dimensional information.

Abstract: A feed indexing device for a draftsman's straight-edge includes a control member that can be selectively linked to a straight-edge carriage plate. When the control member is linked to the carriage plate, it is rotated proportionately to carriage plate movement. An indexing mechanism is included for allowing the control member to only rotate a preset distance for each resetting thereof. A brake mechanism is included for braking further movements of the carriage plate during resetting of the control member.