Extendable step ladder
US5000289A · kind A · utility
Inventor
Key dates
| Filing date | May 21, 1990 |
| Grant date | Mar 19, 1991 |
| Priority date | — |
| Expiry date | May 21, 2010 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE06C1/22
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A folding step ladder of multipart construction that is extendable from a standard base height to a series of heights incrementally greater than the standard base height, and that is composed of four ladder elements; an upper-front element joined to an upper-rear element at a top hinge-step, a lower-front element slidingly joined to the upper-front element along its length, and a lower-rear element slidingly joined to the upper-rear element along its length. The lower elements captively slide along the length of their corresponding upper element and are capable of being held at a particular incremental extension by a latch arrangement that engages the upper element when downward force is exerted on the ladder.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.