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).

  • Patent number: 5362009
    Abstract: A corner belt guide roller for use in a belt driven tape cartridge is disclosed. The roller controls drag on the driving belt to maintain magnetic tape tension and reduce variability in the cartridge operation. The guide roller is mounted on a pivot pin through an inner cylindrical surface. The inner cylindrical surface has an oriented controlled texture including axial splines. This enables the guide roller to have controlled friction with its pivot pin, and provide a predetermined constant amount of drag to the driving belt to improve the consistency of the tape cartridge operation.
    Type: Grant
    Filed: October 15, 1993
    Date of Patent: November 8, 1994
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: William L. Howard, Jr., David P. Smith
  • Patent number: 5358193
    Abstract: A belt driven reel-to-reel tape cartridge includes two tape guides for guiding the tape to and from respective tape reels. The tape guides have a large radius of curvature and are flanged to form a long trough to guide and align the tape to improve tape tracking. This also provides hydrodynamic lift by creating an air film between the tape and the tape guide to reduce the friction between the tape backside and the tape guide. The radius of curvature can be constant or can vary from a larger radius at the ends to a smaller radius in the middle.
    Type: Grant
    Filed: August 4, 1993
    Date of Patent: October 25, 1994
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: David D. Madsen, David P. Smith, Robert A. von Behren
  • Patent number: 5265331
    Abstract: Hydraulic piston pumps and motors are used in various applications to power implements, steering, propel, and auxiliary systems. However, it is important to keep the piston weight and compressible fluid volume low in order to have a smaller more efficient pump. The subject piston is manufactured in a simple manner to achieve a reliable, light weight design. The piston has a cylindrical body having an outer surface. The piston is manufactured by forming a first bore having a large diameter in the body extending from the outer surface and terminating at an annular shoulder. A second bore is formed which extends from the annular shoulder to a predetermined depth. A tube is inserted through the bore and extends a predetermined distance into the second bore. A cap has a bore and is positioned on the body in abutment with at least a portion of the outer surface. The cap slidably receives the tube through the bore.
    Type: Grant
    Filed: January 16, 1992
    Date of Patent: November 30, 1993
    Assignee: Caterpillar Inc.
    Inventors: William K. Engel, Guy C. Carlson, Jr., Howard Savage, David P. Smith, Phillip J. Wenger
  • Patent number: 5199660
    Abstract: A thin, continuous, flexible drive belt for a belt-driven data cartridge. The belt has a rectangular rib which extends longitudinally along the center of the face of the belt that contacts a tape pack contained within the cartridge. The ribbed belt allows the tape pack to operate at greater transport speeds and acceleration rates by creating a pair of air channels extending the full length of the contact area between the belt and tape pack, resulting in effective removal of air at the belt/tape pack interface.
    Type: Grant
    Filed: April 2, 1992
    Date of Patent: April 6, 1993
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: David P. Smith
  • Patent number: 5049978
    Abstract: A conductively enclosed hybrid integrated circuit assembly for use with microwave and millimeter wave signals is disclosed. The enclosure utilizes a silicon substrate into which recesses are formed by conventional silicon etching processes to support individual MMIC chips with their surfaces flush with the unetched substrate surfaces. The assembly is covered with a thin solid dielectric layer, perforated over points of connection and followed by a metallization to provide point-to-point connections. The arrangement provides one or more levels of patterned metallizations with additional levels being provided either by additional dielectric layers or by forming the silicon substrate from three or more laminar elements and providing a patterned metallization on the surface of an intermediate element. Efficiency in signal grounding and in rf transmission line paths is assured by surface metallizations and the provision of low impedance paths through the substrate.
    Type: Grant
    Filed: September 10, 1990
    Date of Patent: September 17, 1991
    Assignee: General Electric Company
    Inventors: David A. Bates, Ronald B. Browne, David P. Smith
  • Patent number: 5014734
    Abstract: Quick drop valves are usable in hydraulic circuits in which fluid is expelled from a hydraulic cylinder due to gravity force acting on a load connected to the hydraulic cylinder. The present quick drop valve has a sleeve carried by a valve member for establishing an orifice through which the fluid expelled from the hydraulic cylinder passes. When the flow rate of the expelled fluid exceeds a predetermined flow rate, a differential pressure generated by the orifice causes the valve member to start moving toward a quick drop position. In so doing, the sleeve quickly establishes a more restrictive orifice to immediately generate a higher differential pressure to cause the valve member to quickly move to the quick drop position. The more restrictive orifice also causes a greater amount of the expelled fluid to be returned by the valve member to the expanding ends of the hydraulic cylinders, yet still allows sufficient flow therethrough so that the quick drop action can be stopped if so desired.
    Type: Grant
    Filed: August 31, 1990
    Date of Patent: May 14, 1991
    Assignee: Caterpillar Inc.
    Inventor: David P. Smith
  • Patent number: 4581189
    Abstract: In a tape which is driven by an elastic pretensioned belt, discontinuities such as embossings in the surface of the belt promote the release of air from between the belt and the underlying tape, thus minimizing variations in tape tension and tape speed.
    Type: Grant
    Filed: May 9, 1984
    Date of Patent: April 8, 1986
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: David P. Smith, Robert A. von Behren
  • Patent number: 4466564
    Abstract: In a tape which is driven by an elastic pretensioned belt, discontinuities such as embossings in the surface of the belt promote the release of air from between the belt and the underlying tape, thus minimizing variations in tape tension and tape speed.
    Type: Grant
    Filed: September 14, 1981
    Date of Patent: August 21, 1984
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: David P. Smith, Robert A. von Behren
  • Patent number: 4466874
    Abstract: The invention deals with a method of electroding a poly(vinylidene fluoride) solid in a piezoelectric application. The electroding method entails surface preparation of the poly(vinylidene fluoride) by a variety of steps including plasma etching to create temporary molecular scale surface irregularities followed by sputtering a metallic layer before deterioration of the plasma etched surface. The chromium may be the initial metal sputtered, followed by a sputtered copper layer, followed in turn by at least one heavier electrodeposited conductive layer. The method may be conducted without deterioration of the piezoelectric properties of the material. The method has been found to provide very good adhesion between the electrode and the PVF.sub.2 surface.
    Type: Grant
    Filed: September 29, 1983
    Date of Patent: August 21, 1984
    Assignee: General Electric Company
    Inventors: Robert E. Belke, Jr., Richard J. Hill, Raymond A. Shirk, David P. Smith