Abstract: Embodiments are directed in part to endovascular prostheses and methods of deploying same. Embodiments may be directed more specifically to stent grafts and methods of positioning and deploying such devices within the body of a patient.

Abstract: A pressure tank fault detector and method provides a system for detecting a fault in a pressure tank, such as a well water tank. The system includes a current transformer positioned adjacent a pump power wire. A circuit includes a timer, a data recorder, and a system status indicator. When the pump operates, the current transformer sends a signal to the circuit and the timer measures the signal duration. The data recorder logs a short cycle when the timer measures less than a selectable predetermined amount of time. When two or more short cycles are recorded, a signal indicates that a tank fault has been detected. Preferably, the system includes a test circuit and permits a user to select the number of short cycles before the alarm and whether to record only consecutive short cycles. Optionally, the system detects and signals pump cycles that exceed a predetermined excessive run time.

Abstract: A pressure tank fault detector and method provides a system for detecting a fault in a pressure tank, such as a well water tank. The system includes a current transformer positioned adjacent a pump power wire. A circuit includes a timer, a data recorder, and a system status indicator. When the pump operates, the current transformer sends a signal to the circuit and the timer measures the signal duration. The data recorder logs a short cycle when the timer measures less than a selectable predetermined amount of time. When two or more short cycles are recorded, a signal indicates that a tank fault has been detected. Preferably, the system includes a test circuit and permits a user to select the number of short cycles before the alarm and whether to record only consecutive short cycles. Optionally, the system detects and signals pump cycles that exceed a predetermined excessive run time.

Abstract: Methods and apparatus are shown for correcting velocity-induced offset errors in a digitizing system when the cursor is moved diagonally across a sensing grid. Primarily, this is a system for reducing the offset error in the actual and depicted cursor position when a pen cursor is moved rapidly over a digitizing screen of a pen-driven computer. It also provides double the number of positional outputs for added accuracy. A triplet of data is formed by taking two samples from one axis and one from the second axis. The two samples are averaged to form one component of the cursor position and then the average along with the single sample from the other axis are output as the positional coordinates. A second sample is then taken from the second axis to form a new data triplet. The averaging process is repeated with the two data points from the second axis and the average along with the second sample from the first axis are output as a next position of the cursor.

Abstract: A device for imparting a signal phase status of an alternating current (AC) magnetic field signal transmitting from a cursor in a cordless digitizer. The device includes an apparatus for causing the cursor to temporarily emit a signal having a frequency which is lower than the frequency of a basic cursor signal, and an apparatus for determining and imparting the signal phase status of the AC magnetic field signal transmitting from the cursor as derived from the temporarily emitted lower frequency signal.

Abstract: In a pen cursor for use in performing writing motions on the surface of a tablet, this is a sensor for mounting in a tip portion of the pen cursor to develop a signal output indicating longitudinal force on a writing tip of the pen cursor. A tip member extends from the tip portion of the pen cursor and is mounted for longitudinal movement. It has a plunger portion extending therefrom within the pen cursor. A resistive member and a conductive member are disposed within the pen cursor behind the plunger portion. The plunger portion forces the resistive member and the conductive member together in electrical contact over a contacting area which is directly proportional to the amount of longitudinal pressure on the plunger portion. A voltage is connected across the contacting area whereby resistance as a function of longitudinal pressure on the plunger portion can be measured.

Abstract: In a cordless, electro-magnetic digitizing system having a drive circuit outputting a square wave drive signal of known initial polarity to a transducer coil in a cursor to oscillate the transducer coil and cause a magnetic field output therefrom which is detected in an associated tablet, a method of operation and associated apparatus for determining the phase of a response signal induced by the magnetic field from the response signal itself.

Abstract: A hand-operated optical scanning system which can be used to scan a large document in multiple passes. There is a digitizing tablet containing position-sensing circuitry for outputting a signal indicating the position of a sensing coil in an x-y coordinate system associated with a working surface of the digitizing tablet as well as a buffer memory for receiving pixelized data associated with optical scanning of a document. A hand scanner for scanning the document comprises, a case having a longitudinal axis, guide rollers for allowing movement of the case only substantially along the longitudinal axis, a read bar centered on the longitudinal axis and perpendicular thereto for optically scanning a one-dimensional line of pixels and for outputting a signal reflecting an instantaneous scanned image, and a sensing coil carried by the case centered on the longitudinal axis at a pre-established distance from the read bar for being positionally sensed by the position-sensing circuitry of the digitizing tablet.

Abstract: In an electro-magnetic, cordless digitizer system wherein a transducer emits an AC magnetic field which is detected by a first grid of scanned parallel first wires in a tablet to provide positional data for the transducer in a first axis of a coordinate system and which are detected by a second grid of scanned second wires in the tablet to provide positional data for the transducer in a second perpendicular axis of the coordinate system, a method and associated apparatus for obtaining a phase reference signal; to be used in a demodulator demodulating data signals from the first and second grids of scanned first and second wires.

Abstract: In a digitizer tablet system employing a tablet having equally spaced parallel grid wires disposed in a plane along an axis parallel to the tablet's upper surface and a pen cursor having a sensing coil disposed concentric with and perpendicular to a longitudinal axis of the pen cursor to develop a characteristic output waveform from electromagnetic inductance between the grid wires and the sensing coil, this invention is the method of compensating a calculation of the position of the pen's tip on the tablet's upper surface and along the axis determined from an interpolation of the characteristic output waveform to find its zero voltage crossing point for tilt of the pen cursor longitudinal axis from perpendicular to the tablet's upper surface comprising using voltage values from grid wires next on opposite sides of the zero crossing point to calculate a pen tilt compensation factor.

Abstract: A method and associated circuitry for use in an electromagnetic digitizer having a plurality of first grid conductors connected from a first multiplexer controlled by a first enable input to ground and a plurality of second grid conductors connected from a second multiplexer controlled by a second enable input to ground and crossing over the first grid conductors at multiple points for eliminating errors caused by capacitively coupled signals between the grid conductors at the cross over points.

Abstract: In a digitizer system, a grid comprises a group of X conductors and a group of Y conductors, each such group comprising a first and second set of conductors. The first set in each group is formed by looping a predetermined number of conductors back and forth across the grid active area so as to provide a plurality of crossing conductors segments. The second group is formed by looping a different number of conductors back and forth across the active area in the spaces between the conductors of the first set so as to provide a plurality of second set crossing conductor segments alternating with said first set crossing conductor segments. Due to the differing number of conductors in the sets and their alternate looping across the grid active area, the positional and directional polarity relationships between the crossing conductor segments shift across the active area, enabling segments to be distinguished from one another and treated as if they were separate and distinct wires.

Abstract: An improvement to position digitizing devices wherein sensed response voltages caused by the interaction of a movable instrument relative to conductors beneath a planar surface are converted to digital form and digitally processed to determine instrument position. An integrating voltage to frequency converter is used to produce a frequency with a correspondence to the voltage applied to it. By counting the frequency for a defined length of time, a resultant count is obtained which also corresponds to the applied voltage. By varying the counting period under microprocessor control, acquisition rate and resolution can be varied over several orders of magnitude without changing circuit components. The digitizer includes conductive elements disposed across the digitizing surface and incorporated into an instrument for producing an analog voltage signal having a DC component related to the position of the instrument on the digitizing surface.

Abstract: A digitizer wherein the transduction frequency is controlled (automatically or manually) to minimize the interference effect of sources of external AC fields, such as CRT monitors. The digitizer implements the method of operation comprising the steps of, connecting a source of a frequency higher than the frequency to be employed as the transduction frequency of the digitizer to the first input of a counter; receiving input pulses from the source at the first input of the counter; outputting output pulses which are employed to generate the transduction frequency in the digitizer at an output of the counter; selectively setting an initial count value at a second input of the counter; and, repeatedly counting from the initial count value at the second input to a terminal value, outputting an output pulse upon reaching the terminal value, and resetting to the initial count value after outputting each output pulse.

Abstract: A cementing plug container for enclosing and injecting cementing plugs into the casing of an oil or gas well to reduce contamination on the interface between the well fluid and the cement, which container includes a shaped housing containing one or more plugs, a plug release mechanism for each plug, which release mechanism is characterized by an air cylinder and a cooperating plug support and release assembly which function to drop the plug or plugs from an upper interior segment of the housing into a lower interior segment or bore responsive to operation of the cylinder.