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Thread: Loading ramp design options
07-12-2007, 09:49 AM #1
A friend of mine recently acquired an old Inter 4 x 4 light truck that he intends to use for transporting car wrecks and more useable vehicles. The truck will be fitted with an electric winch which will pull the vehicles up on to the bed.
The body/deck/bed is 14' long and about 4' off the ground. He is proposing to build what is called a beaver tail, fixed ramp making the loading ramps, often loose pieces which just hook on, short and light enough to manhandle about.
The challenges are several in this proposal, the most serious, in my opinion, being the 4' height of the bed. Does anyone know the optimum or maximum safe angle that the ramp or beaver tail should be?
I can see lots of benefits in a hydraulically operated two part ramp but cost might well rule this out. A search in the general forum did not reveal anything close to this topic.
Does anyone have any designs or recommended steel profiles likely to meet the service requirements? Do you have your ears on AAB?
07-12-2007, 10:39 AM #2
Poking my nose in where I have no specific expertise, I would ask do others use a similar truck for the same application? If so check out their design and copy it.
If you over-engineer these ramps they will likely be too heavy to manhandle. I'd guess that the maximum safe angle may well be limited getting the sill of the vehicle over the 'round over' of the intersection between ramp and bed to prevent grounding. You obviously want some sort of safety factor but this will be difficult to judge unless you know the weight of whichever car is lifted.
No help I know, still whats new?
07-12-2007, 11:09 AM #3
In some places, a "light truck" would be too small to haul a car on its deck. I am sure Queensland has its own definitions. A ute would not have a fourteen foot bed. I have seen photos of rather large trucks hauling three trailers of logs or some such down some road in Australia.
Maybe it would be more practical to pull a car hauling trailer with the truck. A car trailer would come equipped with detachable ramps and be ready to use. It would have a deck around two feet off the ground.
You might even figure out how to use the trailer ramps to get a car from the trailer up on the truck deck. I suppose the trailer deck would be about half the height of the truck deck, so it might be done. Then you could haul two cars at once.
07-12-2007, 11:17 AM #4
Al asks, "do others use a similar truck for the same application?"
The answer is no. Not that I'm aware of. The usual truck would be the height of a tilt tray or lower. Maybe 2'6" or even 750mm. Not 1200mm or thereabouts.
I am thinking of a curved intersection between bed and beaver tail and grounding is a factor.
I am trying to consider options and advantages and disadvantages.
07-12-2007, 11:28 AM #5
Larry you are thinking as I am. A beaver tail might limit the ability to contrive a tow hitch as well as reducing the high clearance existing at present.
I think we should take advantage of the all terrain aspects for this recovery vehicle rather than limit them.
Weight or carrying capacity would not be a limitation. I believe that it is down graded to 21/2 tons capacity for off road situations and around 4 tons for road conditions. Certainly not in the category of a "Ute".
Which reminds me of a large local construction company whose foreman had an 8 wheeler for his Ute as he called it. It had an enormous knuckle boom crane fitted which limited its load capacity to 9 tons. It was specially made for carrying, lifting and placing electrical transformers for the power supply authority which was the original owner.
07-12-2007, 11:35 AM #6
The problem is not in getting the car up the ramp but in getting it over the "hump" where the ramp meets the truck bed. A quick calculation for say a Dodge Neon yields a 20 foot ramp to raise the car 4 feet and have a shallow enough angle as to not bottom the car at the hump. So the ramps would need to be longer than the bed creating a storage problem as well as a handling problem.
07-12-2007, 11:50 AM #7
I was thinking of placing a wideish roller in the centre of the bed to allow the winch cable to accommodate the angled pull over the hump without chaffing. The same sized rollers where a car tyres/sills would track might help minimise any scraping.
Naturally a 20' ramp is out of the question. The design would have to be based on the average wheel base and minimum ground clearance of a standard sedan.
07-12-2007, 12:07 PM #8
how about adding a jack to the front of the vehical to raise the front axel thus reducing the hump? Could be like a down rigger, fairly simple with out adding rear axel weight.
07-12-2007, 12:12 PM #9
I saw a tip truck made that way. Two long stroke hydraulic cylinders just behind the front wheels lifted the whole front of the truck to tip the contents of the fixed body out the back. An ugly solution but engineering is about lateral thinking and finding original solutions.
07-12-2007, 01:16 PM #10
One posibility for your ramps, would be to make them multi-part. Have the rearmost sections like long loose "car ramps" and engage a bridging section from the truck to them with "hooks". A couple of hooked poles could also hold the "ramps" in their correct place. The bits will still be long and heavy though. Thought, could they be stored under the bed of the trailer?
07-12-2007, 09:16 PM #11
The following are an overkill for what you want, but it may give you some ideas.
Note the fall in the tray to minimise getting over a hump.
07-12-2007, 10:14 PM #12
In NYC the configuration of a JUNK car pickup vehicle is similar to what you are looking for. a 16-20 beavertail flatbed, over the top is a frame which supports an I beam from front to just past the end of the beavertail. A cable winch at the front of the body, cable vertical to a block, then to a second block at the end of the I beam. In use they back up to end of the car hook the cable to something down low, lift up that end and back the truck underneath, unhook cable and run it to the far end of the car, hook onto whatever looks good, then winch the car right into the truck. No more that 2 minutes work. These are Junk cars, once stickered by traffic they are fair game for the first guy who spots them.
07-12-2007, 10:19 PM #13
Just make the bed tilt in place (pivot).
The bed tilt could be as simple as an appropriately-sized air cylinder with mechanical safety blocks or stops, although I'd prefer hydraulics.
Then the hump goes away, use short ramps made of ladder-frame channel and heavy expanded metal, just pull the car up towards the headache rack and then tilt the bed back to level.
Same concept as a rollback tow truck but the bed doesn't necessarily need to translate if you are using ramps.
07-13-2007, 12:59 AM #14
Firstly thanks to everyone for your contributions.
AAB said. "Note the fall in the tray to minimise getting over a hump." I don't understand what you are alluding to Alex. All I am seeing is the conventional beaver tail back. Is that what you mean.
The design in the pictures you supplied would be over design in our application but our bed height would be higher than the truck in your pictures and therefore the loading ramp or ramp and beaver tail would be more difficult.
Some of the suggestions that seem possible are having the bed pivot at the hump to reduce the angle and avoid grounding. Matt's suggestion. An alternative to that is a separate frame sitting on the bed which can be raised and lowered at the front.
Tom's suggestion has no regard for the damage possible when loading the wreck and we want to avoid any damage.
A thought incorporating some suggestions here has occurred to me:- Is it possible that the loading ramp could be loose, both sides each supporting either side of the car are tied together (fabricated as one piece) rollers are placed at frequent intervals on the bottom under the frames on each side.
When the car tied to the ramp is pulled up on to the truck, the pivotting point is encountered at the hump and the winch pulls the ramp/cradle and car over the pivotting point and the rollers take the load on the truck bed and advance the load to the front of the bed. Spring loaded pins could be fitted under the bed which could be held below the deck level and with a twist of a special tool project up through anchor holes in the travelling pallet, if you like, and with lynch pins hold the cradle/pallet in place fixed to the truck.
Is there any future in this suggestion?
The hump or pivot point is envisaged as some substantial rollers at the hump or perhaps just at the end of the bed and without any sort of a beaver tail at all.
07-13-2007, 02:39 AM #15
Here are some pictures of the beast in question. The bed height measures a little over 1300mm at the back axle.
07-13-2007, 11:15 AM #16
BTW, you may want to figure out just how much problem the bump is. I had a situation where I would occasionally have to move a Mini-Cooper from ground level up to a low, 36 inch, loading dock. A 12 foot ramp worked just fine. The cars had 15 and 16 inch rims, standard 24 inch diameter tires, so the clearance was probably about standard. After the cars were brought up they would be put on dollys so they could be pushed into the office. Long story....
Also, that bed looks to have a lot of clearance over the tires, can he change the springs to bring it down a bit? or lower the frame somehow?
07-13-2007, 06:18 PM #17
Damien. I have a similar truck a 1964 AACO182D and I can tell you will not load cars on it with out a tipping tray. I load mostly tractors with a heavy ramp that has a bend in it to do the same as a beaver tail would do. I allso load a vintage truck with 160" WB and to do that I run the front wheels up on a ramp and use a lot of extra timber to get it up with out hitting. My advise is to make the tray tip and buy a set of aluminum ramps or tow a traller. Same cost even with a 12volt winch on the trailer witch will be a lot easyer to use.
07-13-2007, 08:06 PM #18
I didn't think a vehicle was made that got less mpg than my dually.
Now I see I was wrong
07-13-2007, 08:23 PM #19
Just as I suspected! "Light truck" in Australian has a whole different meaning than over here. Second observation is, what an ugly truck! Then I saw that beautiful IH emblem on the front. I worked for International Truck engineering here, from 1963 to 2003. I do know we had a manufacturing and sales presence in Australia, but I never got a road trip to see it. I am sure that cab was never on a USA civilian model IH truck. It looks very military, and probably locally made.
07-13-2007, 10:04 PM #20
I would borrow some engineering thought from the ATV and Lawn Mower guys. If you curve the ramps. It is a whole lot easier to load something with low ground clearance like a mower. Something like this just one a larger scale.