For this year 2012, we thought to redo the most mechanical parts of our Versatower HF pylon.
This one is erected since the begenning of the clubstation (1982), and it was urgent to take care of it, the fresh and salty britainy air has not arranged the affair...
In this first part, we describe the conception and the installation of the hoist to secure tilt operation.
The mast is a Versatower biggest model (3XHD with its trussed base FBPX).
The first thing very surprising is that the genuine mast does not have any hoist to tilt the main pole. The simple idea to manipulate the mast only with ropes and by hand, made us hesitate about the cazy things that could happen if the affairs go wrong.
If you look closer, you could suspect that the designers have thought to this problem because the pivot point located at about 6m above ground and the conterweight blocks make all this hardware balanced.
However as the future installation of another antenna system will generate a sizeable imbalance, we decided to make a winch identical to asymmetric models as BP60. Namely, a luff tackle.
The main challenge is to design a winch system irreversibly, with a relatively modest cost, pulled from recycled materials.
A trip to the local junkyard permitted us to find a gear and worm wheel which was used to handling a metal curtain.
the gear ratio is about 1:40 to 1:50, which is perfect for irreversibility, one ton capacity (more than enough).The original engine was fried, we decided to use the winch manualy, as its use is more episodic, it will be easy to adapt a drill motor if needed.
From the perspective of mechanical design, a calculation under simple stress with a large coefficient of security, or the well known proverb "I don't calculate, I'll make bigger"
CLICK ON THE IMAGES TO ENLARGE
As seen in the real world:
The movable assembly (Wire rope eye splice)
Moment of truth
F8RDO (Mich, maneuvering , easy!) 1PÉKAB!!!
B&D motorisation (we accept any compensation!)
to be continued....
Creation date : 02/04/2012 11:06
Last update : 18/04/2012 22:50
Category : Projects
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