Abstract: A trocar obturator includes a hollow tube having a substantially solid, optically clear tip attached thereto. A distal cutting end of the tip is formed by a pair of opposing, angularly oriented surfaces which converge to a line at that point with a cutting element disposed along the line. For electrosurgical operation, an electrode is positioned along the line. The tip serves as a viewing window and defines a viewing port at its proximal end for an endoscope inserted into the hollow obturator tube for viewing a tissue wall as it is penetrated. The trocar obturator tip may include an axial bore extending between its proximal and distal ends with a viewing rod within the bore for viewing the area ahead of the tip. Here again, the distal cutting end of the tip may be formed by a pair of opposing angularly oriented surfaces which converge to a line. Two cutting elements extend linearly along the distal end of the tip, one on either side of the bore.

Abstract: A fiber optic signal collection system and method for position sensing or sensing other parameters indicated by light distinctive patterns. The system is particularly suitable for use in aircraft flight control. The system includes a set of fiber optic fibers with first and second ends. The first ends are disposed adjacent a light distinctive pattern indicating a particular pattern such as a relative position. A portion of the second ends are positioned adjacent a light source and a portion of the second ends are disposed adjacent a light sensing electrical device such that light from the light source can be conveyed through the fibers, reflected from the light distinctive pattern, and conveyed through the fibers to the light sensing electrical device in order to detect the pattern in the electrical device.

Abstract: Tissue impedance or tissue impedance in combination with tissue temperature is used to control electrosurgical tissue treatment. Tissue impedance alone provides better control of electrosurgical treatment by determining an initial maximum tissue impedance, a minimum tissue impedance selecting a point between the maximum and minimum impedances, preferably the average, as an impedance threshold, and turning off rf power to the electrosurgical instrument when the impedance reaches the threshold as it rises from the minimum. Control may also be by the combination of tissue impedance and temperature. Temperature is controlled to maintain a selected preferred temperature and a maximum temperature is also selected so that if the tissue reaches the maximum temperature, power is turned off. Impedance control is combined with temperature control so that the temperature of the instrument is maintained at a selected preferred temperature unless a maximum temperature is exceeded, which normally will not happen.

Abstract: A trocar obturator includes a hollow tube having a substantially solid, optically clear tip attached thereto. A distal cutting end of the tip is formed by a pair of opposing, angularly oriented surfaces which converge to a line at that point with a cutting element disposed along the line. For electrosurgical operation, an electrode is positioned along the line. The tip serves as a viewing window and defines a viewing port at its proximal end for an endoscope inserted into the hollow obturator tube for viewing a tissue wall as it is penetrated. The trocar obturator tip may include an axial bore extending between its proximal and distal ends with a viewing rod within the bore for viewing the area ahead of the tip. Here again, the distal cutting end of the tip may be formed by a pair of opposing angularly oriented surfaces which converge to a line. Two cutting elements extend linearly along the distal end of the tip, one on either side of the bore.

Abstract: A novel position sensing device and novel method for determining position use an electronic memory to retain a look up table for calibrated position indicia on a scale. The position indicia are preferably arranged along the scale so that at least two indicia are positioned at unique distances apart in each length segment of the scale. A reader electrically reads the at least two indicia of a segment and the electronic memory look up table allows the at least two indicia to determine the segment, position within segment, and the position relationship between the position within the segment and the reader. Preferably, the indicia are slits in a scale bar, and the reader is a light source and charge-coupled device. The position of the slits is preferably determined using more than one pixel of the charge-coupled device.

Abstract: A fiber-optic position sensor includes a light source, a light detector that produces analog electrical signals proportional to the intensity of incident light on the detector, and fiber-optic bundles for transmitting illumination light to an object, transmitting reflected light from the object to the detector, and reference light from the light source directly to the detector. Electronic circuits are also provided for use with the optical position sensor for processing the signals from the detector to determine the position of the object. The detector is a photovoltaic bi-cell having two discrete regions, the first being used to detect the reference light and the second being used to detect the reflected light. A mounting block configuration is also provided to conveniently hold the optical elements.

Abstract: A structure which has a low coefficient of thermal and moisture expansion along one dimension (an axis) is formed of an arrangement of fibers surrounded by and bonded to an engineering thermoplastic resin. The fibers are arranged so that essentially all of the fibers are disposed parallel to the axis. The fibers have a negative coefficient of expansion, the resin has a positive coefficient of expansion, and the volume ratio is balanced so that the composite structure has a near zero coefficient of expansion. Perferably the structure is formed by pultrusion of overlapped tapes of aligned carbon fibers preimpregnated with polyphenylene sulfide. A scale having this structure has slots for indicating position on the scale. The slots extend through the scale and are transverse to the axis.

Abstract: A light source providing a diffuse, uniform intensity of light over a length of the device. A prism of material having a relatively high index of refraction has a shape to capture light emitted longitudinally therein by light emitting diodes molded into the ends thereof. A window, such as a frosted surface of the prism, allows the light to be emitted from the prism. The window has a shape which tapers toward the light emitting diodes so that a linearly uniform amount or intensity of light is emitted along the length of the window.

Abstract: A carriage and housing for a position sensing device of the type having a carriage for carrying a reader for reading the position of the carriage with respect to the housing along a position line of the device. The improvements include a carriage with five bearings to restrict the carriage to motion parallel to the position line. The carriage and housing are isolated in a frame of reference by the housing having first and second planar reference surfaces on which the bearings ride and first and second springs which urge the carriage toward the first and second reference surfaces by contact with first and second spring supports which form part of the housing and extend parallel to the first and second reference surfaces and the position line. A yoke moves the carriage but is isolated from the carriage by a five degree of freedom of movement connection. The yoke has arms with facing bearings which contact but float on planar bearing surfaces on the carriage which extend perpendicular to the position line.