Patents by Inventor David P. Smith
David P. Smith 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: 6224065Abstract: A face seal for forming a sealed condition between two spaced, opposed surfaces. The face seal includes an inner seal retainer member and an outer seal retainer member each defining an area having an axis therethrough. The inner and outer seal retainer members each having a first axial end portion, an opposite second axial end portion, and an axial extent as measured between the first axial end portion and the second axial end portion. The outer seal retainer member is disposed radially outwardly of the inner seal retainer member, defining a space therebetween. An elastomeric seal member having an axial extent longer than the axial extent of the first and second inner and outer seal retainer members is disposed in a predetermined portion of the space between the inner seal retainer member and the outer seal retainer member.Type: GrantFiled: May 7, 1999Date of Patent: May 1, 2001Assignee: Caterpillar Inc.Inventor: David P. Smith
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Patent number: 6205000Abstract: The data cartridge drive belt of this invention comprises a layer of a low stiffness belt material and a layer of a high stiffness belt material. By inserting the belt into the tape cartridge so that the high stiffness belt material is adjacent to the tape pack and the low stiffness material is away from the tape pack the neutral axis in the belt is shifted toward the tape pack.Type: GrantFiled: November 30, 1994Date of Patent: March 20, 2001Assignee: Imation Corp.Inventors: Mary R. Hable, Kam W. Law, Christopher J. Zwettler, R. Galen McCrea, Jr., David P. Smith, Jeffrey W. McCutcheon
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Patent number: 6179570Abstract: A variable pump control for a hydraulic fan drive is provided to control the speed of the fan between a maximum and a minimum desired value. A proportional solenoid valve arrangement is provided to established a maximum displacement of a variable displacement pump which drive a fluid motor having a cooling fan attached thereto. A variable electrical signal is directed to the proportional solenoid valve arrangement to proportionally reduce the displacement of the pump thus reducing the speed of the cooling fan to a predetermined minimum desired level.Type: GrantFiled: June 8, 1999Date of Patent: January 30, 2001Assignee: Caterpillar Inc.Inventor: David P. Smith
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Patent number: 6130046Abstract: Techniques for designing polymer probes to verify the integrity of the probe synthesis are provided. Multiple probes with identical sequences are designed so that the probes will be formed utilizing at least one different monomer addition cycle. Based on the probes affinity to a control target, variations (e.g., errors) in probe synthesis may be identified.Type: GrantFiled: August 31, 1998Date of Patent: October 10, 2000Assignee: Affymetrix, Inc.Inventors: Earl A. Hubbell, David P. Smith
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Patent number: 6098491Abstract: A control lever assembly with handle lockout capability including a lever element selectively positionable in a locking position and lockable therein by movement of a handle thereof to a lock position. A first biasing member is disposed on the lever element in an operative position to exert a first biasing force against a detent element, and a second biasing member is disposed in opposition to the first biasing member and is operable to hold the detent element to allow free pivotal movement of the lever element relative to a base.Type: GrantFiled: October 27, 1998Date of Patent: August 8, 2000Assignee: Caterpillar Inc.Inventors: David Carlson, Mark R. Coppley, Michael S. Johnston, David P. Smith
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Patent number: 6098481Abstract: A high force detent mechanism to selectively hold a control input lever in any selected position between neutral and its maximum travel in either direction. The high force detent mechanism includes a coil assembly connected to a control input lever and disposed in close proximity to a semi-circular member having a serrated edge defined thereon. An armature of the coil assembly has a first portion in driving contact with the serrated edge and a second enlarge portion having a latching surface disposed adjacent one of the first and second end faces of the coil assembly's detent coil. The size of the latching surface is larger than the size of the first portion that is in driving contact with the serrated edge. Consequently, the latching force generated between the latching surface and the one face of the detent coil is multiplied several time to create a detent holding force that is larger than the latching force.Type: GrantFiled: December 15, 1998Date of Patent: August 8, 2000Assignee: Caterpillar Inc.Inventors: Rudy V. Mills, David P. Smith
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Patent number: 6056294Abstract: A self energizing one piece seal has an annular seal body and a multiplicity of circumferentially spaced delta shaped resilient tabs extending inwardly from the annular body. The seal is adapted to be placed in an annular groove of a cylindrical member so that a circumferential seal face is initially biased into sealing engagement with a bore of a body and a radial seal face is initially biased into sealing engagement with a radial face of the groove by the resilient tabs.Type: GrantFiled: April 21, 1998Date of Patent: May 2, 2000Assignee: Caterpillar Inc.Inventor: David P. Smith
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Patent number: 6027778Abstract: The present invention provides a novel one-piece capstan for a tape cartridge which provides good static dissipative properties and wear resistance. The capstan material of the present invention has a charge decay time of no more than 5 seconds as measured according to Mil B-81705C standard. The capstan material also has a flexural modulus of at least 200,000 psi (1379 MPa). The capstan comprises a hard, dimensionally stable polymer and a static dissipating polymer. The capstan also has an improved structure and geometry which enables the part to be easily molded, reduces drive force requirements with a reduction of material from the prior art design, but with no significant loss of performance properties.Type: GrantFiled: September 15, 1994Date of Patent: February 22, 2000Assignee: Imation Corp.Inventors: Karunasena A. Alahapperuma, Anthony B. Ferguson, David P. Smith, David L. Tussey, Saurin J. Shah, Dean E. Sitz, Randy S. Bay, Daniel C. Egan, Wolfgang G. Schoeppel
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Patent number: 5897176Abstract: A braking apparatus includes a brake cylinder having a first opening and a second opening defined therein. The braking apparatus also includes a movable member located within the brake cylinder which has a channel defined therein. The braking apparatus further includes a brake chamber in fluid communication with the brake cylinder. The brake chamber has a brake member located therein. The movable member is moved to a position which allows fluid communication between the first and second opening through the channel thus creating a subsequent pressure drop in the system. The pressure drop causes a hydrostatic transmission in fluid communication with the brake apparatus to be neutralized by a responsive displacement of a pump and motor which reduces the travel speed of a vehicle. Additionally, the movement of the movable member causes a brake member to be forced against a moving object.Type: GrantFiled: March 15, 1996Date of Patent: April 27, 1999Assignee: Caterpillar Inc.Inventors: Paul A. Dvorak, Peter R. Hildner, David P. Smith, William C. Swick
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Patent number: 5875682Abstract: Fore and aft movement of a lever pivots first and second shafts of a cross shaped member while left and right movement of the lever causes a yoke of the lever to pivot on third and fourth shafts of the cross shaped member. The pivotal movement of the first shaft causes a pair of end portions of a torsion spring to generate forces on a force sensor resulting in the output of electrical signals proportional to the fore and aft movement of the lever. Similarly, left and right pivotal movement of the yoke causes a pair of end portions of another torsion spring to generate forces on another force sensor resulting in the output of electrical signals proportional to the left and right movement of the lever. Selectively energizing a coil device fixed relative to a mounting base pulls a washer anchored to the second shaft into mechanical engagement with the coil device to hold the lever at a fore or aft operational position.Type: GrantFiled: March 20, 1997Date of Patent: March 2, 1999Assignee: Caterpillar Inc.Inventor: David P. Smith
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Patent number: 5875631Abstract: A hydrostatic transmission has a pair of overcenter variable displacement pumps, each having a flow control element controlled by a double acting actuator to control direction and flow rate of the pump. Fluid pressure in first and second chambers of each actuator are equal at a neutral position of the transmission. A forward control valve controllably communicates the first chambers of both actuators to a tank through a first orifice to reduce the pressure in the first chambers to simultaneously move the flow control elements in a first direction for forward travel. A reverse control valve controllably communicates the second chambers of both actuators to the tank through a second orifice to reduce the pressure in the second chambers to simultaneously move the flow control elements in a second direction for reverse travel.Type: GrantFiled: December 11, 1996Date of Patent: March 2, 1999Assignee: Caterpillar Inc.Inventor: David P. Smith
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Patent number: 5868059Abstract: An electrohydraulic displacement controlled valve module is disposed in a bore of a valve body for controlling fluid flow between first and second ports. A main valve element slideably disposed in the bore is biased to a closed position blocking communications between an annular groove of the valve element and the second port. An actuating chamber defined at one end of the valve element receives pressurized pilot fluid for urging the main valve element toward an open position communicating the first and second ports through the annular groove. A passage communicates the actuating chamber with a control chamber disposed at the other end of the valve element through an orifice. A poppet is disposed within the control chamber and is biased into sealing engagement with an annular valve seat of an outlet port by a feedback spring disposed between the valve element and the poppet.Type: GrantFiled: May 28, 1997Date of Patent: February 9, 1999Assignee: Caterpillar Inc.Inventor: David P. Smith
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Patent number: 5819866Abstract: An active pitch control is provided for counteracting the pitching motion of a mobile machine. The machine has an apparatus for transmitting driving torque from an engine to a pair of pneumatic tires. The pitch control includes a device for detecting a pitching motion of the machine and responsively outputting a control signal. A device receives the control signal and changes the driving torque transmitted to the tires to counteract the pitching motion.Type: GrantFiled: September 9, 1996Date of Patent: October 13, 1998Assignee: Caterpillar Inc.Inventors: David P. Smith, Ronnie L. Satzler
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Patent number: 5809841Abstract: A variable position detent mechanism for latching a control lever at an infinite number of operating positions includes a semi-circular member connected to a support so that its axis coincides with the pivot of the control lever. An electric detent coil is connected to the lever at a location adjacent the semi-circular member so that energizing the detent coil magnetically latches the lever to the semi-circular member.Type: GrantFiled: October 17, 1996Date of Patent: September 22, 1998Assignee: Caterpillar Inc.Inventor: David P. Smith
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Patent number: 5746056Abstract: An overspeed control for a hydrostatic transmission of a mobile machine includes a speed control valve arrangement connected to a fixed displacement pump through a supply line and to a pressure responsive displacement controller of a variable displacement hydraulic pump of the transmission. An overspeed control valve is connected to the supply line and is operative for reducing the fluid pressure level in the displacement controller when the speed control valve arrangement is in an operative position and the rotational speed of the engine exceeds a predetermined level. This reduces the displacement of the variable displacement pump (which acts as a motor in a downhill situation) and thus increasing engine retarding and transmission losses for preventing the positive grade from accelerating the machine, engine and/or the components of the hydrostatic transmission to speeds exceeding their designed limits.Type: GrantFiled: September 30, 1996Date of Patent: May 5, 1998Assignee: Caterpillar Inc.Inventor: David P. Smith
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Patent number: 5722610Abstract: A belt-driven tape cartridge with reduced tape pack deformation and more spatially homogeneous tape tension. The belt driven tape cartridge has a supply side tape hub and a winding side tape hub both rotatably mounted on the base. The tape is wound around the hubs to form a tape pack about each hub. A drive roller is rotatably mounted on the base. First and second rollers are rotatably mounted on the base. The drive belt is engaged on the drive roller, the tape pack on the supply side tape hub, the first and second corner rollers, and the tape pack on the winding side tape hub. The pack belt is engaged between the first and second corner rollers and disposed on the inner side of the drive belt. The drive belt has a width less than a width of the pack belt such that tape pack deformation is reduced and the tape tension is more spatially homogeneous.Type: GrantFiled: November 6, 1996Date of Patent: March 3, 1998Assignee: Imation Corp.Inventors: David P. Smith, Koichi Sano
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Patent number: 5682955Abstract: A blade control system includes a directional control valve, a fluid regeneration valve and a selector valve for selectively controlling fluid flow between a pump and first and second hydraulic cylinders and between the cylinders. With the valves positioned at preselected operative positions, pressurized fluid from the pump is directed to the head end chamber of the first cylinder, fluid expelled from the rod end chamber of the first cylinder is diverted to the head end chamber of the second cylinder, and fluid expelled from the rod end chamber of the second cylinder is combined with the fluid being directed to the head end chamber of the first cylinders to provide two stages of fluid regeneration for increasing the extension speed of the cylinder.Type: GrantFiled: September 6, 1996Date of Patent: November 4, 1997Assignee: Caterpillar Inc.Inventors: Steven L. Groth, Richard A. Arstein, Randall A. Harlow, David P. Smith, Richard J. Skiba
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Patent number: 5577681Abstract: A pack belt or similar mechanism is provided in a two hub, belt-driven data cartridge to press against the tape pack on the take-up hub side of the cartridge when approximately half of the tape has wound onto that hub. The added load from this pressure reduces the speed of the tape-up hub, which in turn reduces the speed differential between the two hubs. Since the speed differential between the hubs causes a gradient in tape tension (bow-tie) as the tape is moved from BOT to EOT, this reduces or eliminates the bow-tie. Adjustment of the relative tensions between the drive belt and the pack belt allows adjustment of the bow-tie, ranging from the normal bow-tie, to near zero bow-tie, to a negative bow-tie. Coating one side each of the drive belt and the pack belt, then having the coated side of the drive belt contact the uncoated side of the pack belt further reduces bow-tie.Type: GrantFiled: June 29, 1995Date of Patent: November 26, 1996Assignee: Imation Corp.Inventors: Koichi Sano, David P. Smith, David D. Madsen
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Patent number: 5447029Abstract: Hydrostatic transmissions are useful for propelling a machine to do work and travel relative to the ground. In performing work functions and during travel it is desirable to adjust machine speed to aid in handling the machine. The subject hydrostatic transmission control system includes a infinitely adjustable creeper hand lever which can be moved to any desired position and be maintained in the selected position until moved by the operator. A spring biased inching pedal can be used in combination with the creeper lever to further adjust the machine speed. This arrangement of components provides a control system for the hydrostatic transmission which can be adjusted and maintained at a desired setting.Type: GrantFiled: April 8, 1994Date of Patent: September 5, 1995Assignee: Caterpillar Inc.Inventors: William C. Swick, David P. Smith
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Patent number: 5435131Abstract: An apparatus and method for controlling a variable displacement motor of a hydrostatic transmission is provided. The apparatus includes an engine, and a hydraulic pump mechanically coupled to the engine. The variable hydraulic motor includes an output shaft. The apparatus monitors rotational speed of the output shaft. The apparatus and method control motor displacement and detect and/or predict the occurrence of an overspeed condition. The displacement of the motor is modified if an overspeed condition is predicted and/or detected.Type: GrantFiled: April 11, 1994Date of Patent: July 25, 1995Assignee: Caterpillar Inc.Inventors: Dennis J. Hausman, Stephen W. Rector, David P. Smith, Steven T. Ufheil