Simultaneous Three-Wavelength Interferometry for Head/Tape Spacing Measurement

Instrumentation for the simultaneous acquisition of three monochromatic interference patterns for the measurement of head/tape spacing in magnetic tape drives is described. An algorithm to process the three images using a weighted average method into a map of the head/tape spacing and an estimated contact pressure map is presented. Both experimental evidence and Monte-Carlo simulation indicate that the three-wavelength technique is an improvement over standard monochromatic techniques. Sample one- and two-dimensional measurements are given.

Dynamic Deflection of Paper Emerging from a Channel

In many machines handling lightweight, flexible sheets, the sheet must transit an open space. Examples include magnetic tape drives, xerographic copiers, and sewing machines. The nonlinear theory of the elastica has often been used to model nonlinear, static deflections. Dynamic modeling is more difficult, and far less studied. Recently, however, L. Mansfield and J. G. Simmonds (1987) have considered the dynamic deflection of a sheet emerging from a horizontal channel at constant velocity and subjected to gravity loading. In this paper, we consider a generalization of that problem to include arbitrary exit angles and an accelerating “feed” rate. Gravity loading is retained. The resulting nonlinear equations of motion are tractable and are solved numerically.

Dynamic Deflection of Paper Emerging From a Channel

For many machines handling lightweight, flexible sheets, it is necessary for the sheet to transit an open space. Examples include magnetic tape drives, xerographic copiers, and sewing machines. The nonlinear theory of the elastica has often been used to model nonlinear, static deflections. Dynamic modeling is more difficult, and far less studied. Recently, however, L. Mansfield and J.G. Simmonds (1987) have considered the dynamic deflection of a sheet emerging from a horizontal channel at constant velocity and subjected to gravity loading. In this paper, we consider a generalization of that problem to include arbitrary exit angles, and an accelerating “feed” rate. Gravity loading is retained. The resulting nonlinear equations of motion are tractable and are solved numerically.