Slide Rule Type Patents (Class D18/9)
Rotary (Class D18/10)
  • Method and apparatus for determining the exponential powers of "i"
    Patent number: 5717193
    Abstract: The present invention provides methods and apparatus for readily determining the value of the imaginary number "i" raised to different exponential powers. Calculations pertaining to the imaginary "i" are commonly encountered in engineering, mathematical and scientific calculations and analysis. In accordance with the present invention, the value of "i" raised to any magnitude of exponential power is readily determined based upon the values of the "ones" and "tens" place of the exponent, including whether the "tens" value is an even or odd integer. Different apparatus are provided for readily calculating the value of the imaginary number "i" for any natural number of exponential power.
    Type: Grant
    Filed: October 21, 1996
    Date of Patent: February 10, 1998
    Inventor: Ruben V. Marcelo
  • Method and apparatus for determining the exponential powers of "i"
    Patent number: 5569896
    Abstract: The present invention provides methods and apparatus for readily determining the value of the imaginary number "i" raised to different exponential powers. Calculations pertaining to the imaginary "i" are commonly encountered in engineering, mathematical and scientific calculations and analysis. In accordance with the present invention, the value of "i" raised to any magnitude of exponential power is readily determined based upon the values of the "ones" and "tens" place of the exponent, including whether the "tens" value is an even or odd integer. Different apparatus are provided for readily calculating the value of the imaginary number "i" for any natural number of exponential power.
    Type: Grant
    Filed: March 24, 1994
    Date of Patent: October 29, 1996
    Inventor: Ruben V. Marcelo
  • Metric converter slide rule
    Patent number: D253114
    Type: Grant
    Filed: December 5, 1977
    Date of Patent: October 9, 1979
    Assignee: Hasbro Industries, Inc.
    Inventor: William Hackemann
  • Metric converter slide rule
    Patent number: D253115
    Type: Grant
    Filed: December 5, 1977
    Date of Patent: October 9, 1979
    Assignee: Hasbro Industries, Inc.
    Inventor: William Hackemann
  • Slide chart
    Patent number: D253830
    Type: Grant
    Filed: June 20, 1977
    Date of Patent: January 1, 1980
    Inventor: R. Wallace Wright
  • Slide frame for calculator or the like
    Patent number: D254078
    Type: Grant
    Filed: June 20, 1977
    Date of Patent: January 29, 1980
    Inventor: Gerrit A. Van Exel
  • Multiple scale rule
    Patent number: D255784
    Type: Grant
    Filed: April 13, 1978
    Date of Patent: July 8, 1980
    Inventor: Douglas D. Seely, Jr.
  • Slide calculator for metal beam dimensions
    Patent number: D265209
    Type: Grant
    Filed: August 8, 1979
    Date of Patent: June 29, 1982
    Inventor: Francois Aiello
  • Electrocardiogram analyzer
    Patent number: D265565
    Type: Grant
    Filed: June 23, 1980
    Date of Patent: July 27, 1982
    Inventor: Frank W. Jackson, II
  • Electrocardiogram analyzer
    Patent number: D267957
    Type: Grant
    Filed: May 26, 1978
    Date of Patent: February 15, 1983
    Inventor: Frank W. Jackson
  • Conversion calculator
    Patent number: D277871
    Type: Grant
    Filed: September 30, 1982
    Date of Patent: March 5, 1985
    Inventor: James E. Bubash
  • Nomograph
    Patent number: D284088
    Type: Grant
    Filed: July 12, 1983
    Date of Patent: June 3, 1986
    Assignee: The Purdue Frederick Company
    Inventors: Erwig Pinter, Michael Oellerich, Gerhard W. Sybrecht
  • Four-in-one pain scale
    Patent number: D561821
    Type: Grant
    Filed: June 15, 2005
    Date of Patent: February 12, 2008
    Assignee: Euro-Celtique S.A.
    Inventors: Stefaan Schatteman, Kris Schellens
  • Refrigeration line size calculator
    Patent number: D289058
    Type: Grant
    Filed: December 13, 1984
    Date of Patent: March 31, 1987
    Inventor: Michael T. Alberts
  • Four-in-one pain scale
    Patent number: D573175
    Type: Grant
    Filed: June 22, 2007
    Date of Patent: July 15, 2008
    Assignee: Euro-Celtique S.A.
    Inventors: Stefaan Schatteman, Kris Schellens
  • Growth ruler or the like
    Patent number: D308884
    Type: Grant
    Filed: June 10, 1986
    Date of Patent: June 26, 1990
    Inventor: Magnus Michaelsson
  • Dosage calculator
    Patent number: D597591
    Type: Grant
    Filed: December 12, 2007
    Date of Patent: August 4, 2009
    Assignee: Hadasit Medical Research Services and Development Ltd.
    Inventor: Mayer Brezis
  • Slide calculator
    Patent number: D316868
    Type: Grant
    Filed: March 31, 1989
    Date of Patent: May 14, 1991
    Assignee: Schwan's Sales Enterprises, Inc.
    Inventor: Craig E. Johnson
  • Manual calculator
    Patent number: D383774
    Type: Grant
    Filed: April 30, 1996
    Date of Patent: September 16, 1997
    Inventor: Kirk T. Winn