[TowerTalk] FW: Crank up questions.

[Chris]

Due to the position of my tower being very close to my house, I had to build my own raising fixture.  It wasn't hard...two 8' 4x4 posts bolted together in an A frame, standing vertically behind the tower baseplate, and two more 16' 4x4's that bolt to the top of the A frame and go forward and down to the ground like big grasshopper legs.  A Fulton 2550 winch bolted to the A frame did the lifting duty.  The cable went up around a pulley, then down to the tower and back up (2:1).  It wasn't hard to lift (I used a long 1/2" ratchet as the handle to the winch), and was stable under load.  I'm keeping all the parts since that is the only way of getting it down!

Chris
KF7P

On Nov 27, 2013, at 2:12 AM, Roger (K8RI) on TT wrote:

> On 11/27/2013 3:28 AM, Matt wrote:
> 
> A raising fixture similar to the commercial ones is very easy to build. Whether the tower will easily adapt to one is something else, but with a little ingenuity should work.
> 
> 73
> 
> Roger (K8RI)
> 
>> This may or may not be of use to you but thought I would offer an
>> alternative.  I have 4 cranks-ups and 2 don't have raising fixtures.   For
>> each of these without fixtures I elongated the foundation excavation and
>> dropped a 20 ft stick of schedule 40 pipe centered at the appropriate
>> location prior to placing concrete.  I welded cap plates and reinforced
>> mountings for a 2-ton chain hoist at the top of each of these the pipes.
>> Suggest to do the stress and flexure analysis on the lifting loads for the
>> tower before sizing the pipe.   I ended up with 6" pipe on one installation
>> and 8" on the other (a larger HD tower).  On the advice of my structural
>> engineering friend, I fabricated the rebar cages with additional "U" straps
>> wrapped around the pipe on a 2" larger radius tied back deep into the center
>> of the concrete with angle turnouts on the ends.  - and doubled up on the
>> spacing through the bottom (and top for good measure) few feet of the
>> foundation.   This is to strengthen the foundation for the side loads (ie
>> avoid blowing out the side of the foundation at the bottom corner) that are
>> imparted when the pipe is under bending stress.
>> 
>> To raise or lower the tower I just hang the chain hoist on the pipe, connect
>> to the tower and she comes right up - very sturdy.
>> 
>> Good luck on your tower project.
>> 
>> 73
>> Matt
>> KM5VI
>> 
>> 
>> 
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