Spiral staircase
Description
Claims
The ornamental design for a spiral staircase, as shown.
Referenced Cited
Patent History
Patent number: D673691
Type: Grant
Filed: May 26, 2011
Date of Patent: Jan 1, 2013
Inventors: Piero Alessandrini (Rome), Chiara Alessandrini (Rome)
Primary Examiner: Doris Clark
Attorney: Young & Thompson
Application Number: 29/392,782
Type: Grant
Filed: May 26, 2011
Date of Patent: Jan 1, 2013
Inventors: Piero Alessandrini (Rome), Chiara Alessandrini (Rome)
Primary Examiner: Doris Clark
Attorney: Young & Thompson
Application Number: 29/392,782
Classifications
Current U.S. Class:
Stepped (12) (D25/63)