backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

looking to buy a used hyd cylinder on ebay (or some similar source) for
use in a home-brewed tilt trailer. have a couple amateur hydraulic
questions:

if there's no label or tag on a given cylinder, how do you tell by
looking at the cylinder if it's SINGLE acting or DOUBLE acting? also

"all other things being equal", how does one tell what weight, say, a
given cylider can LIFT, straight up? for sake of discussion let's assume
load to be lifted has perfect "zero friction" bearings guiding it. I
assume the answer has a lot to do with size of the cylinder *piston*,
and amount of pressure pump puts out "to" the cylinder ? but what's
the formula?

also, can -ALL- hydraulic cylinders be operated 'in any orientation'?
eg: with cyl body horizontal, vertical, or at any angle anywhere between
the two?

for application in a tiltbed trailer, I assume a cylinder that's bigger
and with a LONGER stroke mounted, say, closer to the hitch, would be
-vastly- better than having a shorter cylinder with an even bigger bore
mounted closer to the axle (so it had a shorter stroke). that be
correct, then?

in same appplication, bubba here also guesses designing a tilt-trailer
to employ very nearly the FULL stroke of the cyl is better that making
it use, say, only half the stroke, correct?

and is there a way for a guy to some sort of 'intermediate throttle
body' or something so that a single-acting cylinder can be made to
perform 'double-acting functions'?

thanks for educating me, guys :-)

toolie

- -
relies by e-mail, if any, please remove the weirdstuff from my address
before you click 'send' - thanks :-)
- -

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

dave wrote:

looking to buy a used hyd cylinder on ebay (or some similar source) for
use in a home-brewed tilt trailer. have a couple amateur hydraulic
questions:

if there's no label or tag on a given cylinder, how do you tell by
looking at the cylinder if it's SINGLE acting or DOUBLE acting? also

Hose fittings. Single hose fitting=single acting, two, double acting.
You can put vents on many double acting cylinders to use as single acting.

"all other things being equal", how does one tell what weight, say, a
given cylider can LIFT, straight up? for sake of discussion let's assume
load to be lifted has perfect "zero friction" bearings guiding it. I
assume the answer has a lot to do with size of the cylinder *piston*,
and amount of pressure pump puts out "to" the cylinder ? but what's
the formula?

Roughly. Use diameter and pressure rating to calculate force
available. (hint-use the diameter to calculate the area acted upon by
the pressure) Make sure to reduce the area by the size of the piston, if
there is one on that side.
Most guys check the column in the catalog that says "force available"
or similar.

also, can -ALL- hydraulic cylinders be operated 'in any orientation'?
eg: with cyl body horizontal, vertical, or at any angle anywhere between
the two?
Mostly. If the seals are working.

for application in a tiltbed trailer, I assume a cylinder that's bigger
and with a LONGER stroke mounted, say, closer to the hitch, would be
-vastly- better than having a shorter cylinder with an even bigger bore
mounted closer to the axle (so it had a shorter stroke). that be
correct, then?

Depends on the load and the design of the tailer. Best is a design
choice. Bigger and longer means more fluid to pack around.

in same appplication, bubba here also guesses designing a tilt-trailer
to employ very nearly the FULL stroke of the cyl is better that making
it use, say, only half the stroke, correct?

You can only get the trailer so empty, then you run out of work to do.
The location of the cylinder, and the location of structure suitable for
the cylinder to act on, determine the location more often than the
stroke of a cylinder does, in my experience. The cylinder does not care
if it is run to full stroke or not.



and is there a way for a guy to some sort of 'intermediate throttle
body' or something so that a single-acting cylinder can be made to
perform 'double-acting functions'?

No. If it's built as a single acting cylinder, that's what it is.

thanks for educating me, guys :-)

You really need to get hold of some catalogs.

Farm implement places and "surplus" places usually deal in Hydraulics
stuff. It is well covered in their catalogs. Do a little chinese
blueprinting. Look at what has been done, There are reasons for everyone
using a similar layout and parts. They work.

toolie

Cheers
Trevor Jones

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

On Sat, 04 Aug 2007 09:35:48 -0400, dave
wrote:
I'm sure that you'll get more answerers to your questions then you
expect but I'll lay a little groundwork:


looking to buy a used hyd cylinder on ebay (or some similar source) for
use in a home-brewed tilt trailer. have a couple amateur hydraulic
questions:

if there's no label or tag on a given cylinder, how do you tell by
looking at the cylinder if it's SINGLE acting or DOUBLE acting? also

A double action cylinder will have a hydraulic oil connection to both
ends of the cylinder although as in CAT blade cylinders the
connections will be at the same end but one will have a pipe going to
the other end.

"all other things being equal", how does one tell what weight, say, a
given cylider can LIFT, straight up? for sake of discussion let's assume
load to be lifted has perfect "zero friction" bearings guiding it. I
assume the answer has a lot to do with size of the cylinder *piston*,
and amount of pressure pump puts out "to" the cylinder ? but what's
the formula?

First there are balanced and unbalanced cylinders. The balanced
cylinders have the piston rod extending all the way through the
cylinder.

The formula for a single action cylinder would be Pi X radius squared
of the piston(in inches) X PSI divided by whatever constant you want
to get pounds /Tons/Etc.

For a double action cylinder the formula would be: Pi X radius
squared of the piston O.D.(in inches) minus Pi X radius squared of
the piston rod X hydraulic pressure in PSI divided by any constant you
need to convert to pounds/tons/etc.

There are also double action cylinders that are not balanced so in
that case you use the formula for a single action cylinder on the end
without the shaft and half of the double action formula for the shaft
end.

Usually you also figure in a fudge factor to make sure it really is
big enough like adding 15 - 25% :-)

also, can -ALL- hydraulic cylinders be operated 'in any orientation'?
eg: with cyl body horizontal, vertical, or at any angle anywhere between
the two?

Up, Down, Sideways, don't make any difference.

for application in a tiltbed trailer, I assume a cylinder that's bigger
and with a LONGER stroke mounted, say, closer to the hitch, would be
-vastly- better than having a shorter cylinder with an even bigger bore
mounted closer to the axle (so it had a shorter stroke). that be
correct, then?

Well, space does enter into things a bit. If you want to raise the
front of the body 6 feet in the air and the cylinder is connected to
the front of the dump bed and the trailer hitch it will have to be a
one of those multiple sleeve cylinders like a fork lift uses - which
probably costs a bit.

If you are serious about building a hydraulic dump trailer then go
look at dump trucks and copy the design. They have been b building
them for yonks and pretty well come up with the best ways to do
things.

in same appplication, bubba here also guesses designing a tilt-trailer
to employ very nearly the FULL stroke of the cyl is better that making
it use, say, only half the stroke, correct?

Whether the cylinder is partially full or partially full of oil makes
no difference as the pressure is constant throughout a closed system..
Most designs are sized so at full travel there is some small clearance
between the piston and the end cap.

and is there a way for a guy to some sort of 'intermediate throttle
body' or something so that a single-acting cylinder can be made to
perform 'double-acting functions'?

Not really.

thanks for educating me, guys :-)

toolie

- -
relies by e-mail, if any, please remove the weirdstuff from my address
before you click 'send' - thanks :-)
- -

Bruce in Bangkok
(brucepaigeATgmailDOTcom)

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

"dave" wrote: looking to buy a used hyd cylinder on ebay (or some similar
source) for use in a home-brewed tilt trailer. have a couple amateur
hydraulic questions: (clip)
^^^^^^^^^^^^^^^^^^
The answers you have received are all correct, but your questions indicate
that you don't know enough about the basics to even consider such a project.
Without understanding the engineering, you could look at other trailers all
day and not absorb the important design criteria.

Things that could go wrong:
1.) You could start the project and never finish it.
2.) You could wind up with a trailer that doesn't work, or doesn't work
very well.
3.) You could wind up with a trailer that breaks with the load raised, and
kills someone.
4.) You could wind up paying someone to unscramble your mess, and spend
more than the cost of a ready-made trailer.


if there's no label or tag on a given cylinder, how do you tell by looking
at the cylinder if it's SINGLE acting or DOUBLE acting? also

"all other things being equal", how does one tell what weight, say, a
given cylider can LIFT, straight up? for sake of discussion let's assume
load to be lifted has perfect "zero friction" bearings guiding it. I
assume the answer has a lot to do with size of the cylinder *piston*, and
amount of pressure pump puts out "to" the cylinder ? but what's the
formula?

also, can -ALL- hydraulic cylinders be operated 'in any orientation'? eg:
with cyl body horizontal, vertical, or at any angle anywhere between the
two?

for application in a tiltbed trailer, I assume a cylinder that's bigger
and with a LONGER stroke mounted, say, closer to the hitch, would
be -vastly- better than having a shorter cylinder with an even bigger bore
mounted closer to the axle (so it had a shorter stroke). that be correct,
then?

in same appplication, bubba here also guesses designing a tilt-trailer to
employ very nearly the FULL stroke of the cyl is better that making it
use, say, only half the stroke, correct?

and is there a way for a guy to some sort of 'intermediate throttle body'
or something so that a single-acting cylinder can be made to perform
'double-acting functions'?

thanks for educating me, guys :-)

toolie

- -
relies by e-mail, if any, please remove the weirdstuff from my address
before you click 'send' - thanks :-)
- -

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

"all other things being equal", how does one tell what weight, say, a
given cylider can LIFT, straight up? for sake of discussion let's assume
load to be lifted has perfect "zero friction" bearings guiding it. I
assume the answer has a lot to do with size of the cylinder *piston*,
and amount of pressure pump puts out "to" the cylinder ? but what's
the formula?

Cross-sectional area of the piston in square inches times pressure in psi
sq.inches times pounds divided by sq.inches = pounds lift

also, can -ALL- hydraulic cylinders be operated 'in any orientation'?
eg: with cyl body horizontal, vertical, or at any angle anywhere between
the two?

Not the ones that are actuated by a lever/piston mounted to one end of the
cylinder, otherwise yes.

for application in a tiltbed trailer, I assume a cylinder that's bigger
and with a LONGER stroke mounted, say, closer to the hitch, would be
-vastly- better than having a shorter cylinder with an even bigger bore
mounted closer to the axle (so it had a shorter stroke). that be
correct, then?

Go look at one and copy their design.

You could certainly spend $20 or so on an engineered set of plans ..

GWE

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

Or, he could start the project and learn. Giving up never taught anyone
anything.

b


"Leo Lichtman" wrote in message
...

"dave" wrote: looking to buy a used hyd cylinder on ebay (or some similar
source) for use in a home-brewed tilt trailer. have a couple amateur
hydraulic questions: (clip)
^^^^^^^^^^^^^^^^^^
The answers you have received are all correct, but your questions indicate
that you don't know enough about the basics to even consider such a
project. Without understanding the engineering, you could look at other
trailers all day and not absorb the important design criteria.

Things that could go wrong:
1.) You could start the project and never finish it.
2.) You could wind up with a trailer that doesn't work, or doesn't work
very well.
3.) You could wind up with a trailer that breaks with the load raised,
and kills someone.
4.) You could wind up paying someone to unscramble your mess, and spend
more than the cost of a ready-made trailer.


if there's no label or tag on a given cylinder, how do you tell by
looking at the cylinder if it's SINGLE acting or DOUBLE acting? also

"all other things being equal", how does one tell what weight, say, a
given cylider can LIFT, straight up? for sake of discussion let's assume
load to be lifted has perfect "zero friction" bearings guiding it. I
assume the answer has a lot to do with size of the cylinder *piston*, and
amount of pressure pump puts out "to" the cylinder ? but what's the
formula?

also, can -ALL- hydraulic cylinders be operated 'in any orientation'? eg:
with cyl body horizontal, vertical, or at any angle anywhere between the
two?

for application in a tiltbed trailer, I assume a cylinder that's bigger
and with a LONGER stroke mounted, say, closer to the hitch, would
be -vastly- better than having a shorter cylinder with an even bigger
bore mounted closer to the axle (so it had a shorter stroke). that be
correct, then?

in same appplication, bubba here also guesses designing a tilt-trailer to
employ very nearly the FULL stroke of the cyl is better that making it
use, say, only half the stroke, correct?

and is there a way for a guy to some sort of 'intermediate throttle body'
or something so that a single-acting cylinder can be made to perform
'double-acting functions'?

thanks for educating me, guys :-)

toolie

- -
relies by e-mail, if any, please remove the weirdstuff from my address
before you click 'send' - thanks :-)
- -

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

Dave, do I have your permission to post your response to me?

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

On Sat, 04 Aug 2007 14:28:07 GMT, Trevor Jones
wrote:

The cylinder does not care
if it is run to full stroke or not.



Cheers
Trevor Jones

If it is a displacement cylinder, it does. They may have no internal
stop and the shaft/piston will simply be pushed out of the cylinder. A
very bad situation now covered with hydraulic oil!

--Andy Asberry--
------Texas-----

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

Andy Asberry wrote:
On Sat, 04 Aug 2007 14:28:07 GMT, Trevor Jones
wrote:


The cylinder does not care
if it is run to full stroke or not.



Cheers
Trevor Jones


If it is a displacement cylinder, it does. They may have no internal
stop and the shaft/piston will simply be pushed out of the cylinder. A
very bad situation now covered with hydraulic oil!

--Andy Asberry--
------Texas-----

All the cylinders I have ever seen, aircraft or industrial, either
limited out against something, whether that was the end of the cylinder
or a limiting device, or were restrained by the item that they were
moving, as in, it only has so much room to move.

It seems a dumb idea, to me, to build a mechanism that will come apart
if not stopped before the end of it's travel.

Cheers
Trevor Jones

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

"Trevor Jones" wrote: or were restrained by the item that they were
moving, as in, it only has so much room to move.

It seems a dumb idea, to me, to build a mechanism that will come apart if not stopped before the end of it's travel.
^^^^^^^^^^^^^^^^^^
That's the thing Andy A was referring to. If a cylinder was restrained by the thing it was bolted to, and was then removed and sold on e-bay, the buyer could accidentally drive it apart and spill oil all over.

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

Will someone tell me why a double-acting cylinder would even be considered
for a tilt bed or a dump bed? Wouldn't gravity would be sufficient for
lowering?

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

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 :-)

toolie

backyard "hydraulics design foramateurs" - tilt trailer cylinder
 

Northern Tool+Equipment have dump trailer blueprints for A 10'X5' and A
14X6'4" in there master catalog. There asking $34.99 and $39.99 for
them.
They also have 2 books on trailer design in there.

Good luck on your project.

H.R.

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

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 :-)

toolie

There is a lot of info in a granger catalog or some other catalogs that
sell hydraulic parts. I think the new MSC catalog even has some info on
Hydraulics. Northern Hydraulics has a page or two on designing
hydraulic stuff.

John

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

Leo Lichtman wrote:
Will someone tell me why a double-acting cylinder would even be considered
for a tilt bed or a dump bed? Wouldn't gravity would be sufficient for
lowering?


A closed system, positive action (to deal with mud, damage, or decay),
and the ability to have the trailer both move as required, and be locked
in the desired position hydraulicly, are what comes to mind.

It would be a little more complex, and perhaps only a percieved
benefit, but I could see it.

Cheers
Trevor Jones

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

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 --

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

"Trevor Jones" wrote: A closed system, positive action (to deal with mud,
damage, or decay),
and the ability to have the trailer both move as required, and be locked
in the desired position hydraulicly, are what comes to mind. (clip)
^^^^^^^^^^^^^^^^
My automotive bottle jack, my automotive hydraulic scissor jack and my
hydraulic press are all single acting. They do not present any problems
from the fact that they take in air as the cylinder extends. As to locking
the tilt bed in place, that is accomplished by closing a valve, trapping
fluid in the cylinder. The extra complexity of a double-acting system to
handle the possibility of sticking seems like huge overkill.

You could, of course, slip the end of the trailer under a load, and use it
for lifting, or maybe for pulling stumps.

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

Leo Lichtman wrote:


"Trevor Jones" wrote: or were restrained by the item that they were
moving, as in, it only has so much room to move.

It seems a dumb idea, to me, to build a mechanism that will come
apart if not stopped before the end of it's travel.
^^^^^^^^^^^^^^^^^^
That's the thing Andy A was referring to. If a cylinder was
restrained by the thing it was bolted to, and was then removed and
sold on e-bay, the buyer could accidentally drive it apart and spill
oil all over.


How about turning off the HTML?


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

Leo Lichtman wrote:
"Trevor Jones" wrote: A closed system, positive action (to deal with mud,
damage, or decay),

and the ability to have the trailer both move as required, and be locked
in the desired position hydraulicly, are what comes to mind. (clip)

^^^^^^^^^^^^^^^^
My automotive bottle jack, my automotive hydraulic scissor jack and my
hydraulic press are all single acting. They do not present any problems
from the fact that they take in air as the cylinder extends. As to locking
the tilt bed in place, that is accomplished by closing a valve, trapping
fluid in the cylinder. The extra complexity of a double-acting system to
handle the possibility of sticking seems like huge overkill.

You could, of course, slip the end of the trailer under a load, and use it
for lifting, or maybe for pulling stumps.


None of those single acting cylinders will likely ever see a load in
the "pulling" direction, such as when the load is moved past the pivot
point of the trailer.

Cheers
Trevor Jones

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

"Trevor Jones" WROTE: None of those single acting cylinders will likely
ever see a load in the "pulling" direction, such as when the load is moved
past the pivot point of the trailer.
^^^^^^^^^^^^^^^^^
If I understand you, you are picturing a load on the aft end of the trailer,
trying to push the bed down, and "stretching" the cylinder. Good point I
hadn't thought of. It could suck in fluid from the supply, past the check
valves. But, couldn't you stop it by just closing the control/bypass valve
between the pump and the cylinder?

Does the kit that Bruce Bergman recommends use a single or double acting
cylinder?

backyard "hydraulics design for amateurs" - tilt trailer cylinder
 

Leo Lichtman wrote:
"Trevor Jones" WROTE: None of those single acting cylinders will likely
ever see a load in the "pulling" direction, such as when the load is moved
past the pivot point of the trailer.
^^^^^^^^^^^^^^^^^
If I understand you, you are picturing a load on the aft end of the trailer,
trying to push the bed down, and "stretching" the cylinder. Good point I
hadn't thought of. It could suck in fluid from the supply, past the check
valves. But, couldn't you stop it by just closing the control/bypass valve
between the pump and the cylinder?

That would still leave seals, designed for load in one direction only,
holding the load. Maybe a problem, or maybe not.

Does the kit that Bruce Bergman recommends use a single or double acting
cylinder?



No idea.

Cheers
Trevor Jones