Building a bed crane. Need advice

[Ironman03R]

Yeah I realised thats my problem, the store bought ones dont use bearings but they put put the mounting point for the cylinder low on the shaft. I was going to buy a hrabor freight one but wanted to be able to transfer it from truck to truck as needed. So I bought the engine hoist used on Ebay for $75.00 and at this point I have 100-120 in the whole project, it will be a little more when I get a couple jacks for outriggers, but I have enough steel left over from the hoist to build a HD engine stand.

 

[Cheaper Jeeper]

You are going to put a jack stand on each side of where the crane mounts into your hitch receiver to keep it from trying to roll to one side or the other, right? What are you going to do to support it and prevent it from twisting away from the truck when the crane is pointed straight back with a load on it?

 

[93turbo_animal]

actually if he puts the jacks down on each end they would become a pivit and actually push up into the truck not pull away

 

[Cheaper Jeeper]

Not in the direction I'm talking about they won't. Picture this. The crane is pointed straight back - parallel to the bed but pointing away from the cab.

Start lifting a load with it and it torque is going to make the crane boom tip towards the ground - unless there is an outrigger or support of some kind preventing it from doing so.

 

[Diezel_Cowboy]

Not in the direction I'm talking about they won't. Picture this. The crane is pointed straight back - parallel to the bed but pointing away from the cab.

Start lifting a load with it and it torque is going to make the crane boom tip towards the ground - unless there is an outrigger or support of some kind preventing it from doing so.

A jack on each end will distribute the torsional force you speek of to the ground. Using the weight of the truck by to provide plenty of surface to ground friction should take care of it. He may even weld some grips to the foot of the jack to make it bite into the ground surface better and stabalize the torsional force.

 

[93turbo_animal]

Start lifting a load with it and it torque is going to make the crane boom tip towards the ground - unless there is an outrigger or support of some kind preventing it from doing so.

With no jack stands down if you pick up a load straight out behind the truck the whole back of the truck is gonna squat trying to pull the hitch off the frame. Now put the jack stands on his cross bar down against the ground and when you pick up that load the down preasure is gonna be on the jack stands with everything behind that going down and everything on the truck side trying to go up. Of course its not going straight up so its still gonna be torqued but the short distance from the jack stands is not gonna be near the torque as from clear out at the end of the boom. If its a good solid hitch I wouldn't be worried about it anyway if I expect it to hold a loaded trailer

 

[Ironman03R]

Updated design

Heres the almost done version, I changed the way the boom mounts to the piviot because I didnt like how much it moved when picking things up. I have a couple of bearing riding on a 1" shaft through the center now. The second "outriggor" will have a trailer jack on it to help preload the main support beam and to allow me to pull the pin in the other stand after the truck is loaded.

 

[Diezel_Cowboy]

Looks like it will be stable to me, but I dunno if i'd want to wrestle it to hook/unhook it to the truck.

 

[obinella]

found this on a welding forum
the outrigger is held on with a pin

 

[Ironman03R]

Mine are pinned on too. Its really not that bad to remove, the boom and upright will slide out of the main beam when you pull the pin. If I want to make it lighter I can just pull the 2 bolts that hold the boom and cylinder on and take that off first. Its heavy but still moveable

 

[typ4]

Mine are pinned on too. Its really not that bad to remove, the boom and upright will slide out of the main beam when you pull the pin. If I want to make it lighter I can just pull the 2 bolts that hold the boom and cylinder on and take that off first. Its heavy but still moveable

Are those bolts that heavy. sorry, I couldnt help it.

 

[Ironman03R]

Yeah they are, but first you gotta get the nuts off!