Sheet measuring apparatus with two structurally isolated non-contacting surface follower bodies and wireless signal transmission

Apparatus for measuring a property such as caliper, weight per unit area, formation or opacity of a sheet which is traveling longitudinally generally along a sheet path, said apparatus comprising

• a sensor body and a target body which during the measurement are located on opposite sides of the sheet and constrained without solid bodily contact (except for accidental or occasional) with the bodies for movement along respective portions of a mutual sensor path intersecting the path of the sheet, the movement being unimpeded by the friction that would otherwise result from solid bodily contact,
• means effective without solid bodily contact (except for accidental or occasional) with the sheet and the bodies for normally maintaining each of the sensor and target bodies at respective, substantially constant distances from the opposite, nominal surfaces of the sheet while permitting the movement of the bodies along the sensor path in response to the position and thickness of the sheet between the nominal surfaces,
• sheet property sensing means, including means aboard the sensor body and means aboard the target body interacting through the sheet to produce aboard the sensor body a response dependent on the sheet property,
• means aboard the sensor body utilizing the sheet property dependent response to produce manifestations thereof and to transmit the manifestations without using solid bodily connections through a space that is unoccupied by a solid bodily connecting member to a location spaced from the sensor body, and
• means including means at the spaced location for detecting the manifestations and producing a sheet property-indicative response.