Lifting Mechanism?

[aggie79]

Took me awhile to get my head around what you were intending to do. 1/2" EMT does bend easily with a bender but still is very strong. You might want to move the points where the springs attach to the scissor jack closer together.

[Barefoot]

<<Imagine a see saw – when you push down on one end, because of the fulcrum point, the other end moves up – there will always be some force exerted up at the hinge joint even with gas springs – some have literally popped the hinge off the galley >>

The hinge on the see-saw is in the middle, so the whole weight of the see-saw is always on the hinge and virtually none is on either end. Yes. On the hatch, though, the hinge is at one end (looking from the side) , so only half the weight of the hatch is on the hinge and the other half is on the floor or on your hand. With the spring also pushing up by your hand, the weight at each end stays half. With the spring pushing up closer and closer to the hinge, it becomes worse and worse (actually approaching infinity!), so the spring will push out the hinge first.

By now I wonder if we are even talking about the same thing. Whatever you wind up with (and why go all complicated?) be sure to mount it right, pushing up (or lifting) near the handle, not near the hinge. I promise not to say any more.

[starleen2]

Barefoot
By now I wonder if we are even talking about the same thing.

Probabally not – but do I see what you mean. By all means feel free to comment on the design. I’m not an engineer but a tinkerer ( I “tink” I can do it)


After reading the response and doing so crawling under the camper I literally hit upon and Idea – My leg on the trailer jack. A rush of ideas came to mind. Why not use a trailer jack instead – it would give me more extension in a narrower space! So Now and Adjustment (please not that this is not to scale)

Here’s a view with it tucked up under the camper. I want the tubes to be on the outside (sorry did not want to cut any more holes in the floor!) Of course they’ll be painted to match

[Lou Park]

I have an idea, but lets see if I can explain it.
Your going to have to remove the top/back to do this.
At the bottom of the rising top, attach an L bracket to the
plywood bottom, then attach seat belt material (because
its skinny and very strong) to the L bracket going in between
the raised top/back and the stationary back. At the top of the
plywood of the stationary back the seat belt material would go
over and back down that plywood over a bearing (metal tube
with a bolt through it.) and down inside the camper wall, through
the floor bent 90deg toward the center of the camper under the
frame to a ratcheting boat winch in the center. One from each
side to the center winch so when you crank the winch, the seat
belt material wraps up and pulls on the belt which pulls the side up.

Lou

[kennyrayandersen]

I have an idea, but lets see if I can explain it.
You’re going to have to remove the top/back to do this. At the bottom of the rising top, attach an L bracket to the plywood bottom, then attach seat belt material (because its skinny and very strong) to the L bracket going in between the raised top/back and the stationary back. At the top of the plywood of the stationary back the seat belt material would go over and back down that plywood over a bearing (metal tube with a bolt through it.) and down inside the camper wall, through the floor bent 90deg toward the center of the camper under the frame to a ratcheting boat winch in the center. One from each side to the center winch so when you crank the winch, the seat belt material wraps up and pulls on the belt which pulls the side up. Lou

OOOH, LOU! You a Genie-us

I like this one – it’s cheaper, and much simpler method; OK, there will still need to be a couple of small slots in the floor, but a small price to pay (and you could cover them from the bottom to keep whatever out). Your wall is ¾ or an inch thick? You can really make this slick by taking a plastic, preferably nylon, Delran, or Teflon (whatever you can get at the local plastic shop that will slide) rod to make a roller. Get it about the same or 1/8 inch bigger diameter than the inside wall thickness. Drill a 16/64 hole (just bigger than ¼ inch hole) down the middle of the rod (someone has a lathe). Make four of them just wider than the seat belt material.

Cut a notch in the top of the inner wall the same length as the plastic ‘cylinder’ (which is the same width as the seatbelt material). Make a couple of notches for the ¼ inch rod to sit into and drop the rod into the cylinder, and the cylinder to the wall. Now you have a ‘roller bearing’ for the seat belt material to slide over the inner wall, between the inner and outer wall, and it will attach to the bottom of the outer wall. On the bottom, near the outside corners you could mount the other two rollers. You’ll need a small slot (same width as the seatbelt material) in the floor just inboard on the inside of the inner wall. Mount the roller just inboard of the slot to guide the seatbelt from horizontal under the floor to vertical just on the inside of the inner wall.

The seatbelt is retracted on a shaft (wound up onto the shaft) with a handle that you turn (Model T anyone?). You mount the shaft in the fore/aft direction below the floor of the trailer. Your mechanical advantage is defined by the length of the handle. Once it’s up it could be held in place by a pin, stop, or you could actually use a mechanism off a boat trailer, complete with a ratchet gear.

This is pretty simple and probably cheaper and definitely easier to fabricate.

If you are having trouble seeing it I could draw up a schematic and send it to you as a word file or something. This would be slick.

[Lou Park]

Draw it up, I can see it in my head, but on paper would be great.
My only concern is when the top is all the way up, the L bracket is
all the way aft, but when in the down position, it looks to be about
12" forward. The L bracket may need to be on a swivel.
Lou

[kennyrayandersen]

Draw it up, I can see it in my head, but on paper would be great.
My only concern is when the top is all the way up, the L bracket is
all the way aft, but when in the down position, it looks to be about
12" forward. The L bracket may need to be on a swivel.
Lou

No L bracket needed -- I'll draw something up!

[starleen2]

Sweet! The distance between the open and closed position is about 23 inches with an arc of 6 inches. I think that 1 inch wide nylon strap will do just fine and forget about the L bracket – I have a pneumatic air tacker – Just staple the strap to the bottom of each wing. Believe me – it ain’t moving. We used to do it all the time with convertible tops and they stay in place at 70 + mph! I won’t even have to take the top off ! Remember folks, I’m only needing to raise the hatch – not support it. Once in the raised position, it is locked into place. Yes, it would involve making some kind of roller bearing. Maybe finding some nylon round stock and drilling through the center for a roller bearing? I guess I could live with a small one inch slot in the floor of each side – I still have some rubber that I could use as a seal. The boat crank winch is also a keeper since it is a force multiplier (can pick one up for about 19.00 usd locally) Could also work with cable, Attach at the bottom at the rear section of the wing with an eyelet screw and run the cable as mentioned and would only have to drill a small hole in the floor Who knows – I may just be able to get rid of that prop rod after all! Kennyrayandersen – get out the ole note pad and show the rest of us what it should look like! (i'm heading out of town for a week)

[kennyrayandersen]

I'm at work now, and finished the sketches. I'll e-mail them to myself and post later (since I can't post from work) -- look for them in the [your] morning.

[Lou Park]

I think that 1 inch wide nylon strap will do just fine and forget about the L bracket – I have a pneumatic air tacker – Just staple the strap to the bottom of each wing. )[/size]

L bracket is up to you, I would be afraid that the tacks would eventually rip out while cranking up. Both at the same time wouldn't be too bad, but if only one ripped it could be disastrous..
Lou

[kennyrayandersen]

I think that 1 inch wide nylon strap will do just fine and forget about the L bracket – I have a pneumatic air tacker – Just staple the strap to the bottom of each wing. )[/size]

L bracket is up to you, I would be afraid that the tacks would eventually rip out while cranking up. Both at the same time wouldn't be too bad, but if only one ripped it could be disastrous..
Lou

Oh, THAT L bracket -- might not be a bad idea there -- I wasn't sure where you were talking about. Pictures in about 10 minutes...

[starleen2]

Are you talking about the L bracket over the nylon webbing?

[kennyrayandersen]

OK,
here goes. I think Lou means the part that attaches the seatbelt to the lower edge of the outer wall.


The first one is a side view hinge toward the right.


View looking aft


roller detail


Crank detail

[kennyrayandersen]

Also, if you got a big enough gap you could use cable -- that way you could route them however you wanted under the tear (not unlike some of the ones in the link you posted)

[Lou Park]

Are you talking about the L bracket over the nylon webbing?

I'm thinking an "L" bracket to go under the lowest part of the movable wing. Kinda like when you grab a piece of plywood with your fingers, your fingers are under the edge of the ply. It doesn't have to be big and thick, (we're only talking approx, 30lbs each) and could be mortised in so it doesn't show.
Lou