Hydraulic Toyota truck project

While surfing the web looking for sources for stuff to rebuild the engine in my 85 1-ton toyota truck, I got thinking about the flatbed I
want to mount on it. So I started looking for makers of flatbeds to get ideas. They are kind of hard to find, but I found a few including Knapheide, who also make service bodies for trucks.
I saw this picture at the Knapheid site that got me thinking. It is called a Knaphoist and it basically turns a flatbed truck into a dump truck.
It is a very compact design, that I believe I can reverse engineer with some help. I am wondering if any of you hydraulic gurus can take a look at it and make some guesses about the cyclinder specs and how big a pump one would need.
http://www.knapheide.com/products/hoists/default.asp
I plan on handling a lot of crushed rock for my driveway. A dump bed would be really handy.
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Many years ago Princess Auto sold kits to farmers. I checked my latest PA catalogue and I don't see them. I am thinking that there must be a supplier of lift kits for farm wagons below the 49th. The lift on the site has a problem that if you expect heavy lifts it just won't do it. A direct lifting multi-stage cylinder is better but needs a big hydraulic tank. Randy
While surfing the web looking for sources for stuff to rebuild the engine in my 85 1-ton toyota truck, I got thinking about the flatbed I want to mount on it. So I started looking for makers of flatbeds to get ideas. They are kind of hard to find, but I found a few including Knapheide, who also make service bodies for trucks.
I saw this picture at the Knapheid site that got me thinking. It is called a Knaphoist and it basically turns a flatbed truck into a dump truck.
It is a very compact design, that I believe I can reverse engineer with some help. I am wondering if any of you hydraulic gurus can take a look at it and make some guesses about the cyclinder specs and how big a pump one would need.
http://www.knapheide.com/products/hoists/default.asp
I plan on handling a lot of crushed rock for my driveway. A dump bed would be really handy.
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But a roller mat is a lot easier, cheaper, and will do the job just fine, with a lot less effect on the way the truck behaves.
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On Wed, 01 Oct 2003 11:11:50 GMT, Ecnerwal
......and in reply I say!:
Do they use those? I have often wondered but thought it was a crazy idea. Great for working underneath the shed etc!
hmmmmm
Actually here,in West Oz, licensing would be more easy. If you make your tray top a tipper, you have to license it again.

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Ernie Leimkuhler wrote:

Cylinder and pump info is listed under the "specifications "link.
Cheers Trevor Jones
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Here is the page in the Pricess auto book: http://www.princessauto.com/downloads/catalog242/hyd-CAN.PDF this is the hoist cylinder only, but the hoist mechanism is listed on page 311. Check it out. It is a pdf, and will take a couple minutes to load.
They list 2 cylinders. One is a 4" bore, 7 ton, the other is a 5" bore 12 ton. 3000 psi max cont. pressure.
Cheers,
Dale

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We have a local company (in Queensland, Australia) that makes tipping trailers using air bags and exhaust gas, the idea is so simple and easy to use you'd never want to try and use hydraulics on a small vehicle.
The bed is hinged at the rear, two spring loaded locks to hold the bed down at the front. The air bag is located under the trailer bed on a flat steel platform, its angled rearward so some basic geometry would be needed to set it up.
The exhaust hose has a valve on it and a rubber cone to fit onto the end of the exhaust.
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On Thu, 2 Oct 2003 06:47:38 +1000, "Roger Martin"
......and in reply I say!:
Three issues. I was building one of these (actually thought of it before I heard about the mob making them. D'Oh!).
Issue one. I have one of the airjack bags that they use. It does not work any more, as it appears to have perished somewhere. I admit it took a few years (2-3?) but it was still a PITA.
Issue two. In WAus, in theory, you still need to relicence the vehicle if you make it a tipper, however.
Issue three. Your exhaust needs to be in top condition to run these things. My best trick was to blow an exhaust join.

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[[ This message was both posted and mailed: see the "To," "Cc," and "Newsgroups" headers for details. ]]

Now that idea I like a lot. Any chance of pictures or a website?
There was a company here in the US selling exhaust powered car jacks that were basically inflatable bags. Same idea.
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wrote:

to
down
steel
set
of
Sorry no website that I'm aware of, and for the life of me I cant remember their name either. I'll see if I can get a photo next week when I go to Brisbane.

I think they use a more robust arrangement - looks like material used in truck air springs. But I'm sure that an exhaust jack would work well and with a larger footprint it would require less chassis subframe modifications.
Big problem with any tipper is twisting the vehicle chassis, using hydraulics can put some really large loads onto chassis crossmembers. I've seen a few horizontally mounted rams which must rely upon the hinge pins being in good condition to rotate around. Regular dump trucks usually have a vertically (just off actually) mounted ram.
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On Thu, 2 Oct 2003 14:34:14 +1000, "Roger Martin"
......and in reply I say!: If you check out the site thet Ernie refers to, they have a complete frame to support the thig, and don't rely on the truck frame. From the forces I worked out, I can see why.

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Here's something similar but it uses a compressor instead of exhaust.
http://www.loadhog.com/instructions.htm
The Web site's pretty crappy but if you read the instructions you can get a pretty good idea of the setup. They installed one on the Trucks TV show and it looked decent.
Best Regards, Keith Marshall snipped-for-privacy@progressivelogic.com
"I'm not grown up enough to be so old!"
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A dump is nice, but it requires hydraulics and a PTO, or a huge electric hydraulic power pack. What type of PTO works on a Toyota truck?
Instead, consider getting a trailer you can dump. If you are doing enough work that requires a dump, you must have a small tractor to push that gravel around.
Put a ball in the bucket of your tractor so you can use the hydraulics of the tractor to dump the trailer.
My trailer was designed with this exact idea in mind. It can be stood on end (dumped) without breaking anything, even when hauling a few tons.

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The thing about dump beds is the bed winds up not rigidly attached to the frame, sometimes not that securely attached either. I think you'd find a rigid bed more useful for your occasional load-limit top-heavy machinery hauling. Now you might build a dump box that mounts over the flatbed - there are some neat "insert" dump beds for pickups that have a smooth interior for easier sliding. No wheel well inserts etc.
I also like the suggestion of the roller mat. I haven't tried it with gravel, but I have several times brought home 2 yards of mulch dumped on a tarp in the pickup bed, and then either tied off the tarp to an anchor and driven the truck out from under it or just pulled out the tarp with power equipment. Gravel is more involved... am sure you can come up with something.
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I know a couple of guys that have used the kits to turn pickups into dump beds. They seem to me to be very light duty setups, very suitable for landscaping type tasks such as brush, limbs and mulch. But not so well suited to heavy loads such as rock or full bed of dirt. Heavy use resulted in worn out everything. Just an observation.
JTMcC.
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Ernie,
You might want to check with the Washington highway patrol before you convert to flatbed. In CA this means you are going to have to stop at truck scales, and your taxes get jacked way up.
A tip bed pickup however is probably still a pickup.
--
Roger Shoaf
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I already checked with the Washington State Patrol. Because it already is a 1-ton truck, they don't care if I turn it into a flatbed.
It would still be exempt from truck scales.
I might not go as far as the tiltbed, but I will be going to a flatbed. I like the idea of a ramp that slides under the bed, and toolboxes under the sides.
And also Flip down side rails that can recieve plywood panels for hauling loose materiel.
Kind of fun to design.
First I need to get the engine replaced with one I rebuild myself, then the flatbed.
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[...]

They list a patent number. Please go to the USPTO web site (www.uspto.org), and type that patent number (US3791695) in their search tools for the patent. The patent has plans. Admitedly, they are lawyers plans (it's still a patent), but they may be of help. The patent expired at least 10 years ago, in case you wonder.
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