Abstract: A mechanical device alternately visually displays measurements, such as measurements of distance, in either one of two different units of measure. The apparatus comprises a dimensionless rotary indicator means carried by a frame to be visually observable by a user. The indicator means has rotatable input means and is calibrated in units and selected fractions thereof. Motion amplifying gear means are carried by the frame and are continuously coupled to the indicator means. The gear means operate the indicator input means faithfully in response to rotation of a rotary input shaft to the apparatus. The gear means include alternate input gears which are alternately engageable in a more directly driven relation with the input shaft than the other. The apparatus also includes selectively operable mode selector means, operable for engaging one or the other of the alternate input gears in said more directly driven relation.

Abstract: A fully adjustable concentric dial indicator comprises a first annular scale member which is adapted to carry indicia around the periphery thereof defining a first circular scale. The second scale member is disposed coaxially of the first and is adapted to carry indicia around the periphery thereof defining a second circular scale. Friction clutch means couple the scale members to a support for selective rotation of the scale members relative to the support in either direction about the common axis. The friction clutch means includes a manually engageable ring member to which only the first of the scale members is fixed and which is rotatable about the common axis of the scale members against the effect of the friction clutch means associated with the first scale member. First and second concentric rotatable shafts are aligned with the axis and respectively carry first and second pointers.