Apparatus and associated methods for forming curved wooden hand rails for spiral staircases and the like
US4953602A · kind A · utility
Inventor
Key dates
| Filing date | Dec 8, 1989 |
| Grant date | Sep 4, 1990 |
| Priority date | — |
| Expiry date | Dec 8, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB27M3/12
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The construction and installation of a curved, laminated wooden bending rail used as a hand rail on a spiral staircase or the like is significantly facilitated utilizing a series of contoured clamp structures which circumscribe the rail and uniformly engage it, at each clamp location, around its entire periphery. Each clamp structure includes a pair of bolt-connected clamping blocks which may be drawn into circumbscribing abutment with and tightened around the rail. When the clamp structure is fully tightened, the surfaces of cutout portions in the two clamping blocks each closely conform to and uniformly engage a lateral half of the rail periphery and laterally clamp the rail laminae together with a clamping force which is very evenly distributed along the nonplanar opposite lateral side surfaces of the clamped rail section, thereby essentially eliminating marring and deformation of the rail caused by clamping force concentrations on circumferentially spaced portions thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.