Production of smoke signs in the air
United States Patent 2674820
US Patent References:
Illuminated sign
- - 1346493
Signaling system
- - 1632106
Electric sign and controlling circuits therefor
- - 1769060
Selective calling circuits
- - 2063354
Station selector system
- - 2184387
Illuminated sign
- - 1346493
Signaling system
- - 1632106
Electric sign and controlling circuits therefor
- - 1769060
Selective calling circuits
- - 2063354
Station selector system
- - 2184387
Inventors:
Krohn, Hansen Rolf
Sidney, Pike Sele
Sidney, Pike Sele
Publication Date:
04/13/1954
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Assignee:
Krohn, Hansen Rolf
Sidney, Pike Sele
Sidney, Pike Sele
Primary Class:
Other Classes:
340/332, 340/825.620, 361/183
International Classes:
G09F21/16; G09F21/00
US Patent References: