Hewlett-packard Company

Flowline, Inc.

Hewlett-packard Development Company, L.p.

Carl R Haynie

James J deBlanc

David Dickey

Jeffrey Dean Wilson

Herbert J Tanzer

Kenneth T Small

James Lawrence White

Brian S Tsuyuki

Mathew A Nieberger

Brian L Benson

William L McGeary

A backplane apparatus for an electronic device enclosure includes a common bus comprising a plurality of signal lines, each signal line having a current limiting element, RA. Isolation circuitry is provided for electrically coupling each of the plurality of signal lines of the common bus to a corresponding plurality of signal lines of the electronic device to enable signal communication between the common bus and the electronic device through the isolation circuitry. In one embodiment, the backplane apparatus further comprises connectors to enable removably attaching the electronic devices such as disk drives. In one embodiment, the isolation circuitry coupling each signal line of the common bus to the connector comprises an inline resistor, RD. The isolation circuitry associated with some of the signal lines may include pull up resistors. The values of RA and RD are selected to ensure that the common bus meets pre-determined current and voltage requirements so that the common bus can change states even if one or more of the devices fail by shorting to ground.

Fault tolerant bus for highly available storage enclosure

A circuit board including differential bus traces on or buried within both sides of the board, interconnecting electronic devices such as disk drives, processors, and connectors for external cables. Via fields, which mimic the size and configuration of the device and cable connector fields, are located between each connector on the board. The via fields link bus traces on or within one side of the board with respective bus traces on or within the other side of the board. The via fields may include subtle, unequal undulations in the trace patterns to provide equalization in the lengths of all trace pairs. The via fields and the connector fields both include repetitive conductor order reversals in the trace connections on opposing sides of the board, to reduce crosstalk between channels. The via fields may be oriented parallel with respect to collinearly arranged devices, or orthogonal with respect to devices or connectors which are parallel. Where a connector has laterally offset groups of pin connections, a via field may also include offset groups of vias to provide trace length equalization.

Circuit board construction for differential bus distribution

Fan brakes for decelerating blower impellers particularly for modular equipment enclosures are described. A module includes a blower having an impeller with a plurality of blades. The brake engages the impeller body or blades when the module is at least partially removed from the enclosure and disengages the impeller when the module is inserted into the enclosure. One brake includes an arm coupled to a braking surface. The arm applies the braking surface to the impeller when disengaged by a cam and retracts the braking surface from the impeller when engaged by the cam. A solenoid may be used in lieu of a cam for directly or indirectly applying the braking surface.

Fan brake for removable module

A power distribution unit adapted for mounting within an equipment enclosure including an inner rack. The power distribution unit includes at least one mounting hinge that is fixedly attached to the power distribution unit housing and which is adapted to fixedly mount the power distribution unit to the rack columns. The mounting hinge is pivotable such that the power distribution unit can be pivoted to an extended position to facilitate removal of removable modules of the equipment components mounted within the equipment enclosure.

Apparatus and method for mounting a power distribution unit within an equipment enclosure

A liquid level sensing apparatus, and related method, that utilizes a tuning fork assembly to detect the presence of not only a liquid or air at a particular location within a container, but also a solid material at that location. The tuning fork assembly includes an excitation transducer and a receiving transducer mechanically coupled to a pair of paddles that are exposed within the container, and a phase-locked loop control system applies an excitation signal to the excitation transducer having a frequency that is regulated to track the tuning fork's resonant frequency. A comparator compares that resonant frequency with a prescribed threshold, to determine whether the tuning fork assembly is disposed in air or a liquid. A failure of the phase-locked loop control system to lock the frequency of the excitation signal at any particular frequency indicates that the tuning fork assembly is over-damped and likely contacted by a solid material. Since the apparatus normally excites the tuning fork assembly at its resonant frequency, this allows the apparatus to be operated at reduced power levels, leading to improved efficiency.

Apparatus and method for level sensing in a container

A time-domain reflectometer is disclosed for reliably measuring the level of a liquid in a tank. The reflectometer emits an acoustic signal into a waveguide that projects downwardly into the tank and receives a return acoustic signal reflected from the surface of the liquid. The time delay between the transmitted acoustic signal and the reflected acoustic signal is a measure of the level of the liquid, and the reflectometer converts this level measurement into a electrical current that is linearly proportioned between predetermined minimum and maximum values. In addition, the reflectometer incorporates a liquid- and vapor-impervious membrane disposed in the path of the transmitted and reflected acoustic signals, adjacent to the transmitter and receiver, to prevent the escape of liquid and vapor from the tank and to isolate the electronics, including the transmitter and receiver, from such liquid and vapor.

Method and apparatus for acoustically measuring the level of liquid in a

A highly manufacturable low cost DC-to-DC power converter uses a control circuit constructed from a '555 type timer IC and a precision voltage reference. The output of the '555 timer is used to drive a MOSFET transistor that alternately energizes and de-energizes a primary winding of a transformer, thereby energizing secondary windings of the transformer. The voltage at the secondary windings is rectified and filtered to form the regulated output supply voltages. A feedback control signal is generated based on a difference between a reference voltage and the a regulated output supply voltage. Based on the feedback control signal, a control window is established within the '555 timer that determines the charging and discharging times of a capacitor. Since the charging and discharging times of the capacitor are exponential, changing the feedback control signal changes the control window, which in turn changes the charging time with respect to the discharging time. While the times change with respect to each other, the sum of the charging time and the discharging time remains relatively constant, so the oscillation frequency remains relatively constant. Accordingly, the present invention achieves pulse width modulation (PWM) type control at a cost much lower than the cost of commercially available controller ICs.

Low cost highly manufacturable DC-to-DC power converter

A magnetic shield is designed to be retrofitted over a flyback transformer of a cathode ray tube display terminal. The magnetic shield consists of a layer of metal conductor, for example mu metal, and a layer of insulation, for example polyester film. The layer of insulation is placed upon the layer of metal conductor and the layers are rolled to form a spiral having greater than two windings. Tape may be used to secure the shape of the spiral. Additionally foam rubber pads may be attached to the inside of the spiral to provide a secure mechanical mounting to the flyback transformer and to provide air spacing as additional insulation against corona discharge. Also shrink tubing may be placed over the spiral to provide additional support to the spiral shape and to provide heat and electrical insulation.

Growing community of inventors

Pilot Hill, CA, United States of America

Carl R Haynie