Patents by Inventor David B Cameron
David B Cameron has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7334534Abstract: A water vessel includes a hull having a maximum width. The hull defines a first portion and a second portion. Each of the first and second portions has an end at which a width of the hull converges relative to the maximum width of the hull. The second portion has a first member that defines a first end and a second end. A coupling member pivotally couples the first end of the first member to the first portion of the hull. The second end of the first member forms a portion of the end of the second portion that converges relative to the maximum width of the hull. The first member is movable relative to the first portion of the hull between a closed position and an open position.Type: GrantFiled: August 3, 2006Date of Patent: February 26, 2008Inventor: David B. Cameron
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Patent number: 7293298Abstract: A self-contained sanitary system for a vehicle includes a toilet with a flush tank for storing a source of flush water. The system further includes a spout in fluid communication with the flush tank. The spout has a first open end coupled to the flush tank and a second open end. The spout is coupled for rotation about a generally vertical axis between a stowed position and an access position. The second end is rotatable relative to the first end about a generally horizontal axis between a fill position and a drainage position. The system further includes a bench and a holding tank. The holding tank is removably associated with the toilet and includes a pair of wheels and a retractable handle.Type: GrantFiled: April 2, 2004Date of Patent: November 13, 2007Assignee: Thetford CorporationInventors: David B. Cameron, Frank Schagen, Carrie E. Hall, Michael B. Fritz
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Patent number: 7124702Abstract: A water vessel has a hull having a maximum width and defines a first portion and a second portion. Each of the first and second portions has an end at which a width of the hull converges relative to the maximum width of the hull. The second portion has a first member defining a first end and a second end. The first end is moveably coupled to the first portion of the hull. The second end is associated with the end of the second portion. The first member is movable between a closed position and an open position relative to the first portion of the hull.Type: GrantFiled: August 5, 2005Date of Patent: October 24, 2006Inventor: David B. Cameron
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Patent number: 6353758Abstract: An electrotherapy method; and an apparatus for delivering electrotherapy to a patient. In particular, a method and apparatus for delivering a lower energy, therapeutically effective electrical waveform to a patient through a defibrillator. The method employed to lower the energy of the waveform can be applied to both internal defibrillators and external defibrillators. Further the method can be applied to any waveform, including monophasic, biphasic or multiphasic. Various custom shapes for a defibrillation waveform can be achieved by adjusting the rate at which the energy is duty cycled throughout any or all phases of the waveform.Type: GrantFiled: September 29, 1999Date of Patent: March 5, 2002Inventors: Bradford E Gliner, David B Cameron, Dennis E Ochs
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Patent number: 6158061Abstract: A sanitary toilet system with an integral water supply and manual flush assembly for a recreational vehicle in which a flush water supply tank is provided adjacent a recreational vehicle wall with an inlet extending through the wall, thus eliminating plumbing within the vehicle between a water inlet and the supply tank. A manually operated piston pump is provided in which a clearance exists between the piston and the pump cylinder allowing water to flow past the piston during operation of the pump. This reduces the forces necessary to operate the pump in comparison to a piston in sealing relation to the cylinder.Type: GrantFiled: January 16, 1996Date of Patent: December 12, 2000Assignee: Thetford CorporationInventors: David B. Cameron, John M. Antos, Charles L. Sargent
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Patent number: 5889388Abstract: A method and apparatus for indicating a low battery condition and for dynamically controlling the load on a battery in order to optimize battery usage. A dynamic load controller for a battery includes detection circuitry for measuring at least one condition related to battery capacity, and power control circuitry for adjusting a power load on the battery based upon the condition. The dynamic load controller may be employed to control the power load on a battery that powers an electrotherapy device, such as a defibrillator. The battery condition may include the slope of a capacity curve, which may be the product of the battery voltage and the power delivered from the battery as a function of the delivered power. Based upon this condition, the power control circuitry adjusts the power load to optimize power delivery from the battery.Type: GrantFiled: December 30, 1997Date of Patent: March 30, 1999Assignee: Heartstream, Inc.Inventors: David B. Cameron, Daniel J. Powers, Douglas H. Roberts
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Patent number: 5773961Abstract: A method and apparatus for indicating a low battery condition and for dynamically controlling the load on a battery in order to optimize battery usage. A dynamic load controller for a battery includes detection circuitry for measuring at least one condition related to battery capacity, and power control circuitry for adjusting a power load on the battery based upon the condition. The dynamic load controller may be employed to control the power load on a battery that powers an electrotherapy device, such as a defibrillator. The battery condition may include the slope of a capacity curve, which may be the product of the battery voltage and the power delivered from the battery as a function of the delivered power. Based upon this condition, the power control circuitry adjusts the power load to optimize power delivery from the battery.Type: GrantFiled: June 6, 1996Date of Patent: June 30, 1998Assignee: Heartstream, Inc.Inventors: David B. Cameron, Daniel J. Powers, Douglas H. Roberts
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Patent number: 5746466Abstract: A door assembly to be attached to a cutout in the side wall of a recreational vehicle for alternatively closing off and providing access to an internal compartment. A body frame is attached to the cut out in the side wall. A door panel is attached by a hinge to the body frame. A pair of push button latch mechanisms, one of which contains an integrated lock, retains the door panel in the closed position. The locking latch may be switched to the locked position when the door is open, automatically locking the door when it is closed. A flexible seal, incorporating a double sealing surface feature, is attached to the perimeter of the door and seats against the frame when the door is closed. The door panel includes a separate door wall and inner and outer door frames which are joined by a retaining clip. The metal retaining clip has a return bent upon itself shape and pointed wedge shaped upset portions for joining the outer and inner door frames.Type: GrantFiled: April 2, 1996Date of Patent: May 5, 1998Assignee: Thetford CorporationInventors: John M. Antos, John R. Selina, David B. Cameron, James M. Byrne, Gerard Cornelis Rijn, Marinus Antonius Ros
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Patent number: 5594287Abstract: A solid state relay, suitable for use in a defibrillator or other high voltage application, is disclosed. Upon activation by a switch, the solid state relay switches power from a high voltage power source, such as a capacitor, to a load, such as a patient undergoing defibrillation. The solid state relay has a group of at least two relay sections that share the voltage load such that no one relay section experiences an overvoltage condition due to the parametric variations of each relay section. Each relay section contains a subsection responsible for balancing the off-state voltage between the relay sections, a subsection responsible for controlling the change of voltage over time as the switch is activated, and a subsection for controlling the change of voltage over time as the switch is deactivated. The solid state relay also contains an output section responsible for minimizing the leakage current from the relay group to the load.Type: GrantFiled: November 4, 1994Date of Patent: January 14, 1997Assignee: Hewlett-Packard CompanyInventor: David B. Cameron
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Patent number: 5483165Abstract: This invention is a battery monitor and battery capacity indicator that uses a sense cell in addition to the main battery to determine main battery remaining capacity and depletion condition. A parameter of the sense cell is related to the main battery capacity so that the main battery will have a minimum capacity remaining when the sense cell parameter reaches a particular value or crosses a particular threshold. In a preferred embodiment, the sense cell is a battery which is identical and of the same manufacturing lot as the battery cell or cells in the main battery pack. A current is drawn from the sense cell that is larger than the current being drawn from the main battery. When the sense cell is fully depleted, the main battery will have a remaining capacity whose magnitude depends on the relationship between the main battery current and the sense cell current.Type: GrantFiled: January 14, 1994Date of Patent: January 9, 1996Assignee: Heartstream, Inc.Inventors: David B. Cameron, Daniel Powers, Thomas Lyster, Carlton Morgan
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Patent number: 5395394Abstract: A solid state relay, suitable for use in a defibrillator or other high voltage application, is disclosed. Upon activation by a switch, the solid state relay switches power from a high voltage power source, such as a capacitor, to a load, such as a patient undergoing defibrillation. The solid state relay has a group of at least two relay sections that share the voltage load such that no one relay section experiences an overvoltage condition due to the parametric variations of each relay section. Each relay section contains a subsection responsible for balancing the off-state voltage between the relay sections, a subsection responsible for controlling the change of voltage over time as the switch is activated, and a subsection for controlling the change of voltage over time as the switch is deactivated. The solid state relay also contains an output section responsible for minimizing the leakage current from the relay group to the load.Type: GrantFiled: June 17, 1993Date of Patent: March 7, 1995Assignee: Hewlett-Packard CorporationInventor: David B. Cameron
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Patent number: 5359307Abstract: A high-speed, relay for switching a high voltage signals includes a set of terminals across which the high voltage signal is applied. The relay also includes a motor having a shaft for movement between an open position and a closed position responsive to actuation of the motor. A contact plate is connected to the shaft which moves responsive to the shaft. A conductor having two contacts at distal ends is formed on the contact plate opposite the terminals such that the conductor does not contact the terminals in the open position and the conductor creates a short circuit across the terminals when in the closed position. The relay according to the invention permits the contact plate to be positioned closer to the terminals which results in a faster switching time.Type: GrantFiled: August 12, 1993Date of Patent: October 25, 1994Assignee: Hewlett-Packard CorporationInventors: Steven A. Mahoney, David B. Cameron
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Patent number: 5285779Abstract: A variable rate defibrillator charging circuit includes a power transformer that accepts an internal battery output and the output from an AC-to-DC converter on separate primary windings. The secondary winding of the transformer is coupled through a rectifier to a storage capacitor. The transformer operates in a fly-back mode whereby energy is discharged into the storage capacitor when the power supplies discontinue charging the transformer. After energy in the transformer is discharged into the storage capacitor, the power supplies are reactivated, recharging the transformer. The separate primary windings of the transformer provide a fast, reliable, low cost means for charging the storage capacitor with multiple power supplies. The AC power source feeding the AC-to-DC converter is detachable allowing the defibrillator to be operated remotely whereby the storage capacitor is charged solely from the internal battery.Type: GrantFiled: March 27, 1992Date of Patent: February 15, 1994Assignee: Hewlett-Packard CompanyInventors: David B. Cameron, Paul D. Bliley
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Patent number: 5203347Abstract: A uni-cable paddle system comprising two paddles with contact surfaces, and a main cable connected at one of its ends to one of the paddles, e.g., the sternum paddle. An inter-paddle cable connects the sternum and apex paddles. The main cable has two high-voltage (HV) wires. One of the HV wires is connected to the contact surface of the sternum paddle; the other HV wire is connected to the apex paddle's contact surface via a HV wire in the inter-paddle cable. Control switches and display indicators may be located on the paddles; the wires for these additional functions may be integrated into the main and inter-paddle cables.Type: GrantFiled: December 12, 1990Date of Patent: April 20, 1993Assignee: Hewlett-Packard CompanyInventor: David B. Cameron
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Patent number: 5060320Abstract: A toilet having a foot pedal flush control comprising two pedals, one for opening a toilet bowl discharge outlet and the other for supplying flush water to the bowl. The pedals both operate through actuation cables having a wire member slidable within a conduit. The flush water pedal can be independently actuated to partially fill the bowl prior to use of the toilet while the outlet closure member pedal coacts with the flush water pedal so that upon opening of the bowl outlet, the flush water pedal is depressed providing water to the bowl. The wire members are solid wire members coupled to the pedals for both pull and push operation so that upon a failure of the pedal return mechanism, the pedals can be manually returned closing the bowl outlet and terminating the flow of flush water to the bowl.Type: GrantFiled: June 25, 1990Date of Patent: October 29, 1991Assignee: Thetford CorporationInventors: Charles L. Sargent, John M. Antos, David B. Cameron
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Patent number: 4982456Abstract: A portable toilet having a fill cap covering the fill opening for a flush water tank. The cap includes a lid with an air vent opening and a seal member captivated in a cage extending downwardly from the lid into the tank, the cap being removably mounted on a tube for filling the tank with water. An air path from the atmosphere to tank is defined by the lid vent opening and an annulus around the seal. The cage is inserted into the tube and should the water splash in the tube the seal is forced upwardly and against the vent opening to prevent water from escaping.Type: GrantFiled: February 27, 1989Date of Patent: January 8, 1991Assignee: Thetford CorporationInventor: David B. Cameron
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Patent number: 4888832Abstract: A flush pump is disclosed for use in pumping water from a storage tank to a toilet bowl for flushing waste from the toilet such as in a recreational vehicle. The pump disclosed includes a housing with a bellows disposed therein with an inlet extending into the flush water storage tank and a discharge connected to the toilet bowl. A piston positioned above the bellows is used to depress the bellows upon rotation of the piston by an actuator above the piston. The actuator includes a cylindrical wall portion extending into the housing having a plurality of vertical flanges extending from the cylindrical side wall engaged with the piston side wall such that when the actuator is rotated the piston will rotate therewith. The housing side wall includes a fixed cam which is engaged with an incline flange cam follower extending from the piston side wall such that the piston will move downward upon rotation of the actuator.Type: GrantFiled: June 17, 1988Date of Patent: December 26, 1989Assignee: Thetford CorporationInventor: David B. Cameron
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Patent number: 4850064Abstract: A portable toilet having a fill cap covering the fill opening for a flush water tank. The cap includes a lid with an air vent opening and a seal member captivated in a cage extending downwardly from the lid into the tank, the cap being removably mounted on a tube for filling the tank with water. An air path from the atmosphere to tank is defined by the lid vent opening and an annulus around the seal. The cage is inserted into the tube and should the water splash in the tube the seal is forced upwardly and against the vent opening to prevent water from escaping.Type: GrantFiled: November 9, 1987Date of Patent: July 25, 1989Assignee: Thetford CorporationInventor: David B. Cameron
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Patent number: 4805660Abstract: An improved vent structure for a toilet which is normally open but automatically closable depending on the water level whereby to prevent unwanted spills allows air to escape from the interior of a flush water holding tank. A cruciform shaped stem including a buoyant body attached thereto reciprocates in a bore, and a seal, provided by an interior bellows or by the buoyant body, closes the air path when the stem is buoyed upwardly by a rise in the water level.Type: GrantFiled: November 9, 1987Date of Patent: February 21, 1989Assignee: Thetford CorporationInventors: John M. Antos, David B. Cameron
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Patent number: D390525Type: GrantFiled: April 2, 1996Date of Patent: February 10, 1998Assignee: Thetford CorporationInventors: John M. Antos, John R. Selina, David B. Cameron, James M. Byrne, Gerard Cornelis Rijn, Marinus Antonius Ros