Method of making spiral staircases
US4831706A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 21, 1988 |
| Grant date | May 23, 1989 |
| Priority date | — |
| Expiry date | Mar 21, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49936
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method of constructing a spiral staircase to the specifications of an architect comprising the steps of taking a plurality of flat rectangular sheets of metal and cutting the front edge at an angle to form the front edge of a tread. Then cutting a pair of stringers in the sheet of metal and bending the stringers downward until they are perpendicular to the tread. Then cutting a riser at the back of the sheet of metal and bending the riser upward. Once a plurality of sheets of metal are formed as outlined above they may be assembled by attaching the stringers of one sheet to the risers of another, forming a spiral staircase. A base for the staircase to rest on and attach the first step to should be employed. The base should be attached to the floor. The base may be made from a rectangular sheet of metal by cutting the front edge at the same angle as the front edge of the tread and then bending a front and rear support for the base in the sheet of metal. At the top of the stairs a plate should be attached to the floor and to the staircase to hold the staircase in place.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.