On Sun, 05 Aug 2007 12:23:59 -0400, dave
wrote:

thanks for your help, guys: trevor, brucedpa, grant, andy. 'light
intro's' to hydraulic cylinders requested, and received, and very much
appreciated :-)

ps - I'm in Gainesville FL, in case of any of you guys sort of near have
an ol' cylinder that might do me some good :-). I'm guessing something
in the *roughly* 3 to 4 inch diameter range, 24 to 36 inch stroke 'more
or less'. I'm a bit on the cash-poor side, but have 'oceans' of extra
tools, components, and hardware type stuff to barter...

again, thanks :-)

Even though it's more spendy, you should consider getting a pre-fab
"tilt-bed hoist kit" (that usually comes with the trailer or truck-bed
mounting and design plans) for your first project. There are way too
many things to go wrong, some that can bite you *hard*.

They use one or two short large OD cylinders (6" to 8" range) in a
"Scissors Jack" linkage arrangement underneath the bed, and all the
engineering work has already been done - the jack assembly is much
less likely to grenade on you due to unforeseen forces in the jack.
There is a reason for the oversized bushings and pins...

Weld the jack in position, hook up the hydraulic lines to the 12V
pump on the trailer tongue, connect a battery, purge the air out of
the cylinder and lines and you are done.

Then you only have to make sure that the bed, hinge and chassis are
built strong enough so they don't break during use, and the suspension
is stiff enough so the entire trailer doesn't get up high in the dump
mode and fall over sideways from trying to dump an unbalanced load -
either of which could /really/ hurt if you are standing in the wrong
place.

Oh, and you always dump a tilt trailer while hitched to the tow
vehicle for the same reason - you don't want to chance the trailer
'turning turtle', going over-center and onto it's back.

-- Bruce --