Abstract: An apparatus for optically scanning and measuring the physical parameters of a sheet material by means which are fully enclosed within an air purged cross-machine box-beam structure to protect the radiation source, the radiation detector and the optics from the harsh machine environment. The apparatus may involve a single beam enclosing a combined source/detector module for reflection measurement or dual beams on opposite sides of the sheet for transmission measurement with one enclosing a source module and the other enclosing a detector module. Standardization means are also provided either in the module itself or as an extension of the beam. Means are also disclosed for sealing the opening in the beams through which the radiation passes.

Abstract: Characteristics of moving webs are measured using a radiation source shutter which is rotatably movable between an opened-shutter position and a closed-shutter position and structured to permit access to the radiation source in the closed-shutter position. The source is configured to produce a fan-shaped radiation beam which passes through the web to a detector. The sizing of the fan-shaped beam and the detector together with the spacing the source and the detector are such that the beam width is substantially less than the detector while its length is greater than the detector. This novel beam shaping, detector arrangement provides composition insensitivity, increases solid beam angle and superior streak detection by aligning the beam length dimension with the direction of web movement.

Abstract: An apparatus for detecting streaks in a moving sheet of material utilizes the signal generating and processing means of an existing spot/hole detection system which provides a series of spot measurement signals generated sequentially as a machine direction series of cross-machine sets and assigns a cross-direction location to each signal. Means are provided for calculating an exponential average of the signals for each of the cross-machine locations. This average is compared with a predetermined standard and an output signal, including a cross-machine location, is generated when the average exceeds the standard.

Abstract: A linear weight actuator includes a clamp assembly adjustably connecting the power screw to the output spindle. The assembly includes an integrally formed key, riding in a slot formed in the actuator housing, which obviates the need for a separate key element. A mounting plate is adjustably clamped to the actuator housing, by a threaded mounting nut, such that the plate may be conveniently rotated relative to the housing. A linear bearing disposed in the mounting nut provides lateral support for the output spindle at a point spaced from the clamp assembly. A clamping ring encircles a thinned segment of the power nut and urges it against the power screw to prevent backlash.

Abstract: An apparatus for drying a moving web includes an elongate support frame, disposed transverse the web, and a number of heater modules releasably attached thereto. The heater modules each include a housing and an inner panel assembly releasably captured therein. An openable cover, in the housing, provides for ready insertion or removal of the inner panel assembly, which rests on two mutually perpendicular support members and is clamped against one of them by the closed cover. A number of heating elements are operatively supported on the inner panel assembly by means which include a locking member displaceable between a first position, whereat all of the heater elements are locked in position, and a second position, whereat the heater elements may be removed.

Abstract: In a scanning head position sensing method and apparatus, a plurality of distinct electromagnetic signals are transmitted from a corresponding plurality of transmitter sites surrounding a central position on one side of a web of material. The signals are transmitted through the web and are received by an electromagnetic energy sensor on the opposite side of the web of material. The electromagnetic energy sensor is positioned to receive approximately equal signal energies from all the transmitters when the energy sensor is positioned substantially opposite to the central position across the web. The transmitters and the sensor are fixedly positioned relative to the first and second sensor heads such that the relative positioning of the heads is determined by combining the signals with one another.

Abstract: A device for measuring the gap between the radiation source and the radiation sensor of a basis weight gauge. A caliper sensor measures the thickness of a sheet of material as it passes through the gap, while the caliper contact shoe rides on the sheet and urges it against a first side of the gap. A linear variable differential transformer measures the distance between a reference point on the contact shoe and the opposed side of the gap. The gap dimension is the sum of the sheet thickness, the distance between the caliper reference point and the second side of the gap, and a readily measurable constant.

Abstract: The stack reflectance is predicted from an on-line, wavelength dependent measurement of the sheet reflectance and the on-line measurement of the sheet opacity at a wavelength interval. The stack reflectance Rst is then used to predict and/or control stack color, preferably by using the parameter K/S=(1-Rst.sup.2)/2 Rst where K is the dye absorption coefficient and S is the dye scattering coefficient.

Abstract: A method and apparatus provide for determining properties of a web of traveling sheet material by scanning light including at least selected wavelengths such as IR and/or visible wavelengths across the web of material and also across at least two calibration samples. The signals generated in response to the scanning of the calibration samples is used to calibrate the scanning operation preferably on every scan. By providing at least two calibration samples, better estimates of average calibration parameters can be made and detection of a faulty calibration sample is facilitated. The calibration samples preferably are protected by mounting them within a scanner housing in relatively close proximity to a scanning beam generator. In addition, at least two compensation samples are supported substantially adjacent the moving web of material and preferably at least one compensation sample is positioned on each side of the web.

Abstract: A pneumatic stepper motor weight actuator captures the advantages of polymeric harmonic gears while occupying less space and eliminating the problems associated with air entrapment in the stator grooves. Air entrapment is eliminated by providing orificed air passages from the bottom of the longitudinal stator grooves to the center stator hole. Advantageously, the actuator includes a rigid gear comprising a toothed polymeric sleeve adhesively bonded inside a metal cup.