This "rubber flex disc" as you call it is a excelent thing to
use to save rotors. Actually, as far as I know, that disc
is called a Hardy disc. They are common on cars like
Ford Granada, BMW and Opel to name a few.
I use a small Emotator rotor to turn a 80 foot rotating
tower with multiple antennas on it, what saves the rotor
is a Hardy disc and I have also mounted an automobile
driveshaft U-joint so I dont have to be all that careful
in geting everything centered, also the bottom of the
tower yanks around a bit so the U-joint will fix it.
No problem with bolts coming loose, dont forget bolts
has to be tightened to proper torque.
73, merry christmas, Jim SM2EKM
--------------------------------------------------------
Mike wrote:
> That was our thinking here, Pete. Big rotator, big antenna,
> HD mast. The rubber flex disc was just something that
> my friend and I thought would be fun to try. We figured
> that as long as that it didn't tend to enhance or sustain any
> mechanical resonances in the system, then it could nothing
> but improve reliability.
>
> Of course experience may prove that we were wrong.
> Currently the rotator is only turning about 200 degrees
> out of 360. I am hoping that its just the a loose bolt keeps
> the output spline shaft from dropping down into the gearbox,
> but I won't know until I climb tower sometime in the next
> few weeks.
>
> 73 de Mike, W4EF.....................................................
>
> ----- Original Message -----
> From: "Pete Smith" <n4zr@contesting.com>
> To: <towertalk@contesting.com>
> Sent: Wednesday, December 19, 2001 5:14 AM
> Subject: Re: [TowerTalk] Hink and Kinks
>
> >
> > At 09:14 PM 12/18/01 -0800, Mike wrote:
> > >
> > >Yes, the drivetrain disks work because they use staggered
> > >bolt patterns each with 4 metal sleeves buried in the rubber
> > >disk. This allows the bolts to be tightened down hard
> > >metal to metal with no sloppy rubber in between the bolt
> > >head and the mating surface.
> > >
> > >In order to install a rotator with rubber shock mounts between
> > >the base and the mounting, a similar scheme that allowed
> > >for hard mounting of the bolts metal-to-metal would be
> > >required.
> >
> > Hi Mike et al. Yaesu apparently makes a device that does exactly what
> Mike
> > suggests. See this dated December 2000 from N7US:
> >
> > "Has anyone used one of these things [Yaesu GA-3000 tower absorber] and,
> if
> > so, what do you think?? They are shown on p. 141 of the Fall/Winter AES
> > catalog. It looks to me to be a two-plate sandwich with big rubber
> > grommets/bumpers in between. I'm assuming it mounts below a rotor to
> > minimize the torque on a tower."
> >
> > In a reply, Mike recounted his experience with a Mercedes drivetrain disk
> > as a mast absorber, which needed jam nuts added to make it hold together -
> > simple lockwashers weren't sufficient over time.
> >
> > I guess I'm not persuaded by the idea that using any such device is just
> to
> > make up for marginal mechanical design. After all, the natural
> environment
> > provides all kinds of uncommon load events -- the 100-year flood, the
> freak
> > windstorm, etc. -- and making provision for such things isn't a bad idea,
> > even if all normal loads are well within spec.
> >
> > This is not to endorse the original Hints and Kinks idea, which I never
> > saw.
> >
> > 73, Pete N4ZR
> > www.qsl.net/n4zr
> >
> >
> >
> >
> >
> > AN Wireless Self Supporting Towers are now available! Windloading tables,
> > foundation diagrams and charts, along with full details are now at the
> > AN Wireless Web site: http://www.ANWireless.com
> >
> > -----
> > FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> > Submissions: towertalk@contesting.com
> > Administrative requests: towertalk-REQUEST@contesting.com
> > Problems: owner-towertalk@contesting.com
> >
> >
>
> AN Wireless Self Supporting Towers are now available! Windloading tables,
> foundation diagrams and charts, along with full details are now at the
> AN Wireless Web site: http://www.ANWireless.com
>
> -----
> FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> Submissions: towertalk@contesting.com
> Administrative requests: towertalk-REQUEST@contesting.com
> Problems: owner-towertalk@contesting.com
AN Wireless Self Supporting Towers are now available! Windloading tables,
foundation diagrams and charts, along with full details are now at the
AN Wireless Web site: http://www.ANWireless.com
-----
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
|