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Patent
   D673691
Priority
May 26 2011
Filed
May 26 2011
Issued
Jan 01 2013
Expiry
Jan 01 2027
Inventors
Alessandri…
Assg.orig
Assg.curr
Entity
unknown
Referenced by
0
References
3
Maint.:
n/a
The ornamental design for a spiral staircase, as shown.

FIG. 1 is a front, left side perspective view of the design for a spiral staircase;

FIG. 2 is a left side elevation view thereof;

FIG. 3 is a front elevation view thereof; and,

FIG. 4 is a top plan view thereof.
INVENTORS:

Alessandrini, Piero, Alessandrini, Chiara

THIS PATENT IS REFERENCED BY THESE PATENTS:
Patent Priority Assignee Title
THIS PATENT REFERENCES THESE PATENTS:
Patent Priority Assignee Title
6155007, Jan 28 1998 Surface tread for a spiral staircase
6523310, Nov 23 2001 Taiwan Lounge Chair Industry Co., Ltd. Tread and handrail combination structure of a staircase
D271524, Feb 17 1981 Spiral stairway
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