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G8MNY > TECH 05.07.05 17:07l 129 Lines 6504 Bytes #999 (0) @ WW
BID : 53034_GB7CIP
Read: OE3KLU GUEST OE7FMI
Subj: A Light 17m /P mast design. 2/3
Path: DB0FHN<DB0RGB<DB0MRW<DB0HOT<DB0HDF<DB0ERF<DB0FBB<DB0IUZ<DB0GOS<DB0EEO<
DB0RES<ON0AR<GB7CIP
Sent: 050705/1052Z @:GB7CIP.#32.GBR.EU #:53034 [Caterham] $:53034_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
PULL UP MAST SYSTEM (Updated Apr 05)
1.5" \°°4 ³ Smaller Pole ³ Guy
Pole °o \ =======³_____ ______³======= Plate
°° Pole ³ ³ o / \ o ³ ³
Pulley °° Holes ³ ³ ³³\/³³ ³ ³ Pulley bolted
Wheel \_ °° / LOCKING ³ ³o[³³||³³]o³ ³ between 2x
|0À°oÄ¿ PIN ³ ³__³³||³³__³ ³ right angles
|³ °°³ÃÄ. ³ ÀÄ||ÄÙ ³ pop riveted On.
Strong | ³ °°³ : ³ || ³ Inside rivets
Nylon\ | ³ °°³ : ³ || ³ hammered flat.
cords | _ ³ ³ : Release ³ Strong Nylon ³
| |0|³ ³³ : Cords
| | ³|³ 3 ³³ : LOCKING CATCH
| | ³|³ ³³ : ³ Inner Tubes Have³ /Pin
| | ³À³__|^Ä¿ : ³ Locating V ===³) <--Screw & Tag
thicker| | ³ ³ÃÄ. : ³Top pole has hole³ÚÄÄÄÄ. Release
rope | | _ ³ 2" ³ : : ³ ³³____/ Leaver
| | |0|³ Tube ³³ : : ³ ³ ³ :
| | |³|³ 2 ³³ : : ³ ³ ³ SPRINGS
| | |³|³ ³³ : : ³_________________³_³__ :
| | |³À³_____|^Ä¿ : : ³ JUBILEE CLIP ³0) :
| | |³ Notch ³ÃÄ. : : ³--------------------' : Release
| | |³ ³ : : : ³ ³³ : Cord
| | |³ 2.5" ³ : : : ³ ³³ :
| | |³ Pole 1 ³ : : : ³ ³
PULL UP ROPES
These are thicker ropes where you hold them (eg 6-10mm) & for poles 3 & 4 are
joined to strong thinner nylon cord (3mm 80kg) that can go over the 2cm dia
pulley & between the poles. The top corners of the aluminium right angle
supporting the pulley is bent over to capture the cord so it can't foul off the
pulley.
On the outer pole I put a rope tie off cleat made from a bent flat strip of
thick metal clamped with a large jubilee clip to the pole.
The ropes are attached to the bottom of the poles by a hole drill in the pole
end. Like the guy plates, these holes are cleaned up to stop chaffing.
The top rope is attached to the bottom of thinnest pole through a diagonal
hole made through it. This insures when the pull up rope is tight the pole is
in the right location for the locking pin to engage.
LOCKING CATCHES
The location of these automatic locking pins determines the amount of pole
overlap. I set the positions to give about 60cm of overlap.
On the top pin system a hole is made in the inter tube. The locking system is
mounted 2cm (1") down on the next tube, so that it clears the guy plate, & a
slot just the width of the pin is cut in the 2nd bigger tube.
Pole
smooth load Ú¿ tag for
rounded ,Ä.__.ÄÄ´³/ wire
nose ³ pin ³³]
`ÄÄÄÄÄÄÄ´³ Screw
small hole ÚÄÁÁÄÄÄÄÄÄÄÄÄÄ. hole for
for wire ³' crank o ³release
bearing ÀÄÂÂÄÄÄÄÄÄÄÄÄÄ' string
³³flat
³³springs
³³
ÄÄÄÄÄÄÄÁÁÂÄÄÄ.
Jubilee Clip ³(/)³
ÄÄÄÄÄÄÂÂÁÄÄÄ'
³³
ÀÙ
The catches uses a shaped steel locking pin (filed threaded pillars) to support
each of the 3 inner sections. The shape has a curved top to ensure the pin
can't release under load. These are attached with 4mm (2BA) steel screws with a
tag to the flat springs which can be made from several old large hacksaw blades
& other flat spring taped together.
The whole locking system is held to the pole with a suitable jubilee clip
around the springs once the outer pole pin hole has been made.
To facilitate unlocking a flat steel strip 1.2 wider than the pin inner pole
engagement length is placed between the spring just under the pin. This is bent
around the spring to form a square flat U with the top the U making the crank
leaver for the release string. A bearing for the crank is formed with 2 small
holes though it just by the bends behind springs & nearest the pin. A sturdy
wire threaded though & attached to the tag completes this bearing.
Warning:- A failure in the release mechanism @ 3m, 7.2m, 11.4m above you, MAY
mean the loss of the mast when it comes to take it down! So make sure you are
happy with it's operation when you make it & each time you use it.
LOCKING LOCATIONS
The bottom of poles 2 & 3 are cut at an angle & a V notch to take the locking
pin. This is opposite the pull up rope tie off hole point. The angle & notch
ensure the pole do not rotate when locked, & easily find the home position when
engaging. As there is quite bit of room between pole 1 & pole 2 spacers are
pope riveted on either side of the thick pull up rope on pole 2 to reduce the
play & keep the bottom of the pole firmly against the catch.
POLES 2 & 3 Lift Rope T O P P O L E
2 holes ||
³ Pin Locating ³ ÚÄ ÄÄÄÄÄÄÄÄÄÄÄÄÄ ÄÄÄÄÄÄÄÄÄÄ ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
³ Notch ³ ³ \===========/ Hole | | Room for³
³ /\ ³ ³ knot | | Aerial ³
³ ³ ³ ³ ³ Tallest Locking | | Shortest ³
³ _.-' `-._ ³ ³ Hole | | Hole ³
³.-' () `-.³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ ÄÄÄÄÄÄÄÄÄÄÄÄÄ ÄÄ ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ -----60cm-------
Lift Rope Hole
The top pole has a locating hole for the locking catch pin to find. This must
be located accurately so that under pull up load it will locate OK. Other holes
can be also be made higher up that pole to enable lower mast height to be used
if it is too windy to do the final lift. In that case the upper guys can be
tied off shorter to improve stability.
LUBRICATION
As aluminium to aluminium mechanics is not hard warring or low friction,
suitable lubrication is need. For the underside of the guy plates & top washer
I use a heavy grease that will not wash away. For the tubes & pulleys, I use
new engine oil, it is easy to apply with each tube pulled out one at a time.
In part 3. Setting up, Erecting, & in Use.
Why Don't U send an interesting bul?
73 de John G8MNY @ GB7CIP
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