Mast extending and rotating apparatus
US4864784A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 15, 1988 |
| Grant date | Sep 12, 1989 |
| Priority date | — |
| Expiry date | Jun 15, 2008 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE04H12/18
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A mast defined by three flexible longerons with cross elements coils into a canister. Extension and retraction are controlled by three axially oriented lead screws which engage protuberances spaced along the longerons. The lead screws are mutually synchronzied by an annular planet gear, and are driven by a spiroidal gear set. At a predetermined mast extension, motor drive is switched over for rotation of the mast rather than extension-retraction. The switch over is controlled by an actuator in the form of a movable guide element dimensioned to clear normal-sized protuberances but to be seized and carried by an oversize protuberance at the desired mast extension. The actuator is coupled to a lock which unlocks the annular gear to the canister so that motor drive results in mast rotation. An auxiliary lock allows re-locking of the canister to the support structure for allowing resumption of the mast extension-retraction mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.