Education and demonstration – Mathematics – Arithmetic
Reexamination Certificate
2007-11-27
2007-11-27
Fernstrom, Kurt (Department: 3711)
Education and demonstration
Mathematics
Arithmetic
Reexamination Certificate
active
11172948
ABSTRACT:
An educational tool including a frame having a rod extending between its opposite sides. A number of beads are slidably positioned on the rod. A reckoning bar is slidably secured to the top of the frame. The reckoning bar bears indicia, for counting the beads, in the form of a series of whole numbers that increase from one side of the frame to the other. Another reckoning bar is slidably secured to the bottom of the frame and bears indicia, for counting the beads, in the form of a series of whole numbers that increase in a direction opposite that provided to the indicia on the first reckoning bar. A slide is slidably secured to the top of the frame for selectively covering the indicia on the first reckoning bar. A second slide is slidably secured to the bottom of the frame for selectively covering the indicia on the second reckoning bar.
REFERENCES:
patent: 452302 (1891-05-01), Denison
patent: 465811 (1891-12-01), Anderson
patent: 1532011 (1925-03-01), Williamson
patent: 2646631 (1953-07-01), Lazar
patent: 3273262 (1966-09-01), Smith, Jr.
patent: 3387392 (1968-06-01), Kurz
patent: 3455034 (1969-07-01), Schott
patent: 3710456 (1973-01-01), Jerman
patent: 4812124 (1989-03-01), Colodner et al.
patent: 5149269 (1992-09-01), Ylitalo
patent: 5205747 (1993-04-01), Tan
patent: 5334026 (1994-08-01), Ylitalo
patent: 5725380 (1998-03-01), Kennelly
patent: 5769639 (1998-06-01), Foster
patent: 6375468 (2002-04-01), Sundararajan
patent: 7077655 (2006-07-01), Watanabe
Fernstrom Kurt
Greiner Stephen R.
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