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PTO
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Patent
D289414
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Priority
Jun 19 1985
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Filed
Jun 19 1985
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Issued
Apr 21 1987
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Expiry
Apr 21 2001
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Assg.orig
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Entity
unknown
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3
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7
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n/a
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The ornamental design for a duct design calculator, as shown.
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FIG. 1 is an isometric view of a duct design calculator showing our new
design;
FIG. 2 is a top plan view;
FIG. 3 is a right end elevational view; and
FIG. 4 is a bottom plan view.
Peters, David C., Williams, Derek P., Chadwick, William C.
| Patent |
Priority |
Assignee |
Title |
| D256472, |
Mar 06 1978 |
Texas Instruments Incorporated |
Case for an electronic calculator |
| D271025, |
Jul 19 1982 |
RJP Electronics Limited |
Combined ruler and electronic calculator |
| D279381, |
Jan 19 1983 |
Cal-Comp Electronice, Inc. |
Calculator ruler or similar article |
| D283515, |
May 20 1983 |
|
Combined ruler and solar cell calculator |
| D284199, |
May 20 1983 |
|
Combined ruler, clock and calculator |
| D285094, |
Jan 26 1984 |
RJP Electronics Limited |
Combined calculator ruler, and desk tray |
| D286161, |
Oct 12 1983 |
Far East United Electronics Limited |
Combined ruler, calculator and clock |
| Date |
Maintenance Fee Events |
n/a
| Date |
Maintenance Schedule |
n/a