Hatch Struts...Formula?

[Steve Frederick]

Got the struts installed, no more prop rods




Rob

Love that Tear!!

[Tim Greiner]

Rob 48-

I had a Design Engineering magazine article on applying these things, unfortunately I can't locate it right now. Most of the advice given in the posts is right on, there are a few more things to consider.

Seals are where these fail, and the way to make them last longer is to mount them with the rod end down so that the fluid stays on the seals and keeps them from drying out. If you can't design the position to do this both up and down, do it in the down position as this is where the most time is spent.

I agree that looking at a factory example is great advice; try to find one that is very close to your application, like a minivan hatch. Just my 2 cents, I would provide positive lift all the way to the down position instead of overcentering and holding it closed, as teardrop hatches have a hefty weight and you need a separate latch to hold it closed. Something like a minivan hatch that has the hinge directly above the hatch in the down position needs no lift near the down position.

Good luck, I think struts are much nicer than broomsticks.

Tim Greiner

[48Rob]

Thank you Tim!

Rob

[Laredo]

is there a pattern available for that silverware basket in the galley? it' s beautiful...

[brian_bp]

...Second, notice that in the closed position, the pressure from the spring/gas-charge is actually pushing the hinge components apart. When mounted in the proper manner, the pressure should push the hinge components together, thereby adding the additional benefit of helping to hold the lid closed.

This doesn't make sense to me. As long as the linkage goes over-centre, it will tend to keep the hatch closed. That can be arranged as easily with Andrew's original configuration as with the other way, right?

I suppose I am much more accustomed to vehicle doors and hatches, which have good latches, than with truck topper and trailer hardware, so using the assist strut to hold the hatch closed doesn't seem like a significant factor.

[brian_bp]

...When the seals fail (and they WILL fail), nasty fluid leaks out...

In a series of cars driven a million of so kilometers over a couple of decades, I have found that hatch struts do eventually get weak enough that I have to replace them, but I've never had one leak. Perhaps the problem is that trailers are used so infrequently that the seals do dry out, while cars are used much more routinely and don't have the same problem.

[grantstew8]

I've found an actual formula for gas struts on a UK site
Download the pdf and go to page 4. You'll need to convert to metric but it's the first time I've found something like this.

[url]http://www.albert-jagger.co.uk/portals/0/010_b1_b_section.pdf
[/url]

[H.A.]

I've found an actual formula for gas struts on a UK site
Download the pdf and go to page 4. You'll need to convert to metric but it's the first time I've found something like this.

[url]http://www.albert-jagger.co.uk/portals/0/010_b1_b_section.pdf
[/url]

For those adverse to the metric systen...
http://www.mcmaster.com/#gas-struts/=pndf45

McMaster Carr is an excellent source of supplies and information.

[grantstew8]

Thanks HA!

[GerryS]

Take a serious look at a solid prop stick. It's not as elegant looking, but these lifts probably won't be used often enough to keep the innards lubricated and effective...

[Kaz]

Thank you all for your input. Still too complicated for my simple mind and I need to get this trailer done. I don't have the time for trial and error or the money. I'm sure I could return the struts I bought and get stronger ones, just don't know what to get. I think I'll go the maple stick for this year.