Method for stretching and folding extension jib in wheeled type crane
US4658972A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 16, 1984 |
| Grant date | Apr 21, 1987 |
| Priority date | — |
| Expiry date | Aug 16, 2004 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB66C23/702
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A method for stretching and folding an extension jib in a wheeled type crane including a telescopic boom, and a suspension-rod-supported compression column type extension jib to be supported in a flat posture at the fore end of the boom in stretched state through right and left jib foot portions rotatably engaged with horizontal boom point pins extending transversely of the boom at the fore end thereof, the method including the steps of (a) providing on opposite sides of the extension jib right and left jib foot portions disengageably engageable with the boom point pins, one of the jib foot portions being rotatable relative to the boom about an axis extending in the axial direction of the jib; (b) stretching the jib from a folded position in which the top and bottom sides of the jib are disposed in an upright posture along one side of the boom, by engaging the one jib foot portion with the boom point pin on the folding side and turning the boom into an inclined position from a horizontal position, rotating the jib around the axis of the boom point pin into a vertically suspended position; (c) turning the jib in the vertically suspended position through a predetermined angle about t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.