So what would you call a *taper* roller bearing? -- it supports loads in
two planes.
73
Alan NV8A
On 07/31/05 02:33 pm Dino Darling tossed the following ingredients into
the ever-growing pot of cybersoup:
> I've been reading this thread with great interest. I wasn't getting it at
> first. Sometimes the term, "thrust bearing" gets confused in the tower
> arena. "Thrust Bearing", in my vocabulary, means taking on SIDE loads in one
> dimension, like a thrust bearing in an engine that prevents the crankshaft
> from moving fore and aft, but not responsible for supporting that crankshaft.
> When we speak of tower masts, we take on loads in two dimensions; vertical
> and side.
>
> So this is how I try to separate the two (your mileage may vary).
>
> The "bearing" used to take the side loads, I call, a "BUSHING". I believe
> the majority of this thread was dealing with this type of bearing. Simply,
> it's a 1" thick triangle plate, the size of, and bolted to, the top/rotor
> plate. The center of this plate is drilled to accept the 2" mast and prevent
> it from touching the tower's metal parts. We rub the bearing rather than the
> metal tower parts. On the top of a "pointy" Rohn section, I've used a piece
> of PVC pipe, the length of the tower tube, as a bushing. In both examples,
> they only provide support in one (side) dimension.
>
> The "bearing" used to take the vertical loads, I call the THRUST bearing.
> It's just like the crankshaft, only flipped up vertical.
>
> (As a side note, it's my feeling that the majority of the bearings (fanfir)
> used to support the vertical load of the mast and antennas is used
> incorrectly. They were designed to support horizontal shafts parallel (load)
> to the flange, not how we use them. But, they seem to work OK. A taper
> bearing would be a better option. IMHO)
>
> What I don't fully understand at this point, is how the UHMW (plastic) sheet
> is used to support the vertical load. I'm assuming you are using 2 sheets.
> How is the second sheet secured to the mast? If possible, a picture is worth
> a thousand words! :-)
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