Gas Shocks / Struts

[atomarc]

Off Topic: did you pick your name based off the ESAB welding electrodes?

Sent using Morse code on - .- .--. .- - .- .-.. -.-

When I picked that name, it was around 1971 and the rod supplier was Chemetron...but yes..it's a stick welding rod which I ran hundreds of pounds of. Good guess.

Stuart

 

[kustomizer]

I have a customer that has a rack on top of his horse trailer to haul his hay when He's on a riding trip, unfortunately He's tired of the hay getting wet and wants me to build a 15" tall cover that is 90" wide by 80.5" long that hinges on the front and latches down in the back, I also have the exact weight of this lid.

So I want to use 2 gas shocks / struts to hold the cover open like the modern day hatch backs have on a car.

My problem is trying to find a company that will tell me the length of the gas shock I need and where to mount the shock in reference to the hinge.

I'm willing to pay for the gas struts and for a engineering and cant find anyone !!!
Any ideas

Our Country Coach RV has gas springs on the storage doors that work great in the Summer but come winter they won't hold the doors open, I switched them out with the next stronger gas springs and now they work in the winter but you almost cant close them in the summer, I like the actuator Idea, Wonder Woman has that on her Ford Expedition, works well every day, even with snow on it.

 

[CatMan]

If you know the exact weight of the cover, then theoretically, if you hinged the cover at the very front, and placed the gas shocks in the middle, then the shocks would need to be rated the same as the weight of the cover. Doubt that's going to lift the rear of the cover very high though. If you hinged the cover in the front, and placed the shocks 1/4 distance away from the hinge, then the gas shocks should be rated at 2x the weight of the cover.

I'd add 20% to the weight ratings. And I'd pick a shock "family" that has some additional ratings above & below what the initial gas shock guess is.

Also, does the shock actually have to support the entire weight of the cover? If these people are physically able enough to get hay on top of their trailer and climb up there and get it down, then why not consider the gas shocks "lift assist" shocks? Have the person lift the cover and maybe there's a prop stick that automatically pops up to hold the lid.

Crazy horse people have no limit on what they will spend on their horses. I have heard in the past that the trailer dealers will finance a horse trailer for up to 40 years. Most of them are broke, but you'd never know it until you went to deposit their check.

 

[Portable Welder]

Thanks for everyone's replies.
Triunph 406, the Guden Calculater was very helpful.

I also found a guy Dan Varey from JWS technologies that is helping me size this.

Ill keep you updated on how everything turns out.

 

[gustafson]

The gas springs on hatchbacks etc are setup in a particular way, so that they are ineffective or very nearly when fully closed. So they do not fly up when you unlock them. Those hatches are also pretty heavy.
If you set the gas spring so that the pivot is oh so slightly higher than the end of the rod when it is closed then it won't fly open when unlatched.

 

[Rob F.]

The gas struts could also hold the cover closed if you raise the mounting point on the roof side above the lid mount. It would be nice if it did not bounce open if they forget to latch it down... I would still put a latch (or lock) on it.

 

[Portable Welder]

Thanks for additional advice, I will definitely latch it down.

 

[DDoug]

Post up your CAD layout here.

 

[Portable Welder]

I finally found a company called JWF Technologies out of OH, I spoke with a guy named Dan Verney and he sized every thing for me and told me what my lift weight would be, what the shut pressure would be and exact points that everything needs to be mounted.

I'll keep you updated on how it works.

 

[ratbldr427]

Be sure to mount them with the rod end down. This keeps oil on the shaft to seal them.They will last a lot longer before the gas escapes.

They also offer them with a rod cover that is loose and falls to one side to lock them open incase they loose gas, wont fall on you.
Its easy to calculate what you need but if that is not your thing then use a pull scale at your proposed mounting point to determine your starting lift force. Depending on the mount angle the force can be rising rate or falling.

Some are available with a bleeder valve so you can reduce force if necessary.

 

[DDoug]

The gas springs on hatchbacks etc are setup in a particular way, so that they are ineffective or very nearly when fully closed. So they do not fly up when you unlock them. Those hatches are also pretty heavy.
If you set the gas spring so that the pivot is oh so slightly higher than the end of the rod when it is closed then it won't fly open when unlatched.

The gas struts could also hold the cover closed if you raise the mounting point on the roof side above the lid mount. It would be nice if it did not bounce open if they forget to latch it down... I would still put a latch (or lock) on it.

Your layout will achieve a "toggle" action when you position your attachment points such that the extending force, when past "Neutral" (or TDC) will now force the hatch shut.

 

[Strostkovy]

I use gas struts all of the time. You need to know the distance from the pivot to the center of gravity of the lid, and the angle of the strut and lid when open.