Lifting Mechanism?

[starleen2]

That's kind of what I'm thinking of for the L bracket - The drawing looks super and really explains the design - think this is what I'm going with! Can't wait till I get back to get started - thanks

[RAYVILLIAN]

Okay Guys this idea is great but I do see what might be one problem with using a strap like a seat belt.

In the first drawing you show the strap going in a V. At first thought you can put the roller at an angle but in looking at my WW that angle is close to 30 degrees and I'm afraid in real life the belt won't want to flex through that much angle and will slip to the side of the roller and possibly jam.

If you used small cable and pulleys to match the size of cable it should work. The cable would flex through the angle easier and wouldn't have to be much since your lifting less than 100 lbs.

I'm trying to figure out how I can retro fit this into the Winter Warrior.

Gary

[ParTaxer]

Maybe I've been watching the history channel too much. I'm thinking of using water or some type of fluid. Like the greeks used to perform mechanical illusions. You would have a reservour at both end of the hatch. Transfer tubes would connect both reservours. Like the sesaw, the weight of the fluid would transfer to the other end by natural gravity when lifting and closing. Might be a wild idea but simpler and less work. The reservours would be somewhat flat and extend along the edge of both ends.

[Lou Park]

Okay Guys this idea is great but I do see what might be one problem with using a strap like a seat belt.

In the first drawing you show the strap going in a V. At first thought you can put the roller at an angle but in looking at my WW that angle is close to 30 degrees and I'm afraid in real life the belt won't want to flex through that much angle and will slip to the side of the roller and possibly jam.

If you used small cable and pulleys to match the size of cable it should work. The cable would flex through the angle easier and wouldn't have to be much since your lifting less than 100 lbs.

I'm trying to figure out how I can retro fit this into the Winter Warrior.

Gary

Although I did not draw the picture, the "V" that you are looking at is a huge distortion and not even close to scale. In reality there is probably less then 1/4" between the wing walls and stationary walls. That is the reason for a strap in stead of a cable. You will have all the strength needed in less than 1mm where as a cable will not only need more space between wall, but will also mark up the stationary wall each time it goes up and down.
Lou

[kennyrayandersen]

Okay Guys this idea is great but I do see what might be one problem with using a strap like a seat belt.

In the first drawing you show the strap going in a V. At first thought you can put the roller at an angle but in looking at my WW that angle is close to 30 degrees and I'm afraid in real life the belt won't want to flex through that much angle and will slip to the side of the roller and possibly jam.

If you used small cable and pulleys to match the size of cable it should work. The cable would flex through the angle easier and wouldn't have to be much since your lifting less than 100 lbs.

I'm trying to figure out how I can retro fit this into the Winter Warrior.

Gary

Although I did not draw the picture, the "V" that you are looking at is a huge distortion and not even close to scale. In reality there is probably less then 1/4" between the wing walls and stationary walls. That is the reason for a strap in stead of a cable. You will have all the strength needed in less than 1mm where as a cable will not only need more space between wall, but will also mark up the stationary wall each time it goes up and down.
Lou

Lou is correct -- I exaggerated that for clarity of kinematics. It should be noted that the top does rotate though an arc and you will want a little angle in there so that half way up it's in perfect alignment and fully down or up the is a little offset -- I don't think it will not be too bad, but you could always use a cable if you had the room or designed in from the beginning (which might be a little more flexible). Fluids can be problematic due to leaks, having to have fluid reservoirs etc. It's hard to beat something that uses a simple cable [or strap] in tension.

[RAYVILLIAN]

The V I'm concerned about is the one in the first pic. If any thing it is under stated. My Warrior hatch drops 25" and in that drop the rear bottom corner of the hatch swings 15" toward the front of the trailer. Even if the attachment point was half way through that arc it would swing 7.5" both ways. The strap might work fine I was just pointing out that there might be a problem there.

Other than that this is the best idea I've seen for lifting the hatch on the Winter Warrior design I'm just trying to figure out how to work it with my drop floor that hangs below the frame rails.

GAry

[Lou Park]

The V I'm concerned about is the one in the first pic. If any thing it is under stated. My Warrior hatch drops 25" and in that drop the rear bottom corner of the hatch swings 15" toward the front of the trailer. Even if the attachment point was half way through that arc it would swing 7.5" both ways. The strap might work fine I was just pointing out that there might be a problem there.

Other than that this is the best idea I've seen for lifting the hatch on the Winter Warrior design I'm just trying to figure out how to work it with my drop floor that hangs below the frame rails.

GAry

That is something that is definitely worth some thought. It is also the very thing that could be taken care of by moving the bearing in 1/3 the distance and then angling the bearing 1/2 the angle. Of course this is all just theory.
Lou

[kennyrayandersen]

The V I'm concerned about is the one in the first pic. If any thing it is under stated. My Warrior hatch drops 25" and in that drop the rear bottom corner of the hatch swings 15" toward the front of the trailer. Even if the attachment point was half way through that arc it would swing 7.5" both ways. The strap might work fine I was just pointing out that there might be a problem there.

Other than that this is the best idea I've seen for lifting the hatch on the Winter Warrior design I'm just trying to figure out how to work it with my drop floor that hangs below the frame rails.

GAry

I'm with you now -- the roller will probably have to be mounted at an angle (tipped down in the back) so the it lines up with the two points at the beginning and end of the arc. The same holds true -- it should split the difference between the positions so that the error is divided by two. I'd have to sit down and play with it, but I'm on vacation and won't be back in the office until Monday next. Chances are someone will have sketched it to scale on a piece of paper and determined what the orientation of the roller needs to be before I can 'officially' look at it. If worse came to worse, it will definitely work with a cable as it would be a lot more tolerant of misalignment.

[Lou Park]

I'm with you now -- the roller will probably have to be mounted at an angle (tipped down in the back) so the it lines up with the two points at the beginning and end of the arc. The same holds true -- it should split the difference between the positions so that the error is divided by two. I'd have to sit down and play with it, but I'm on vacation and won't be back in the office until Monday next. Chances are someone will have sketched it to scale on a piece of paper and determined what the orientation of the roller needs to be before I can 'officially' look at it. If worse came to worse, it will definitely work with a cable as it would be a lot more tolerant of misalignment.

First of all, what the heck are you doing on the computer during vacation, go have some fun. Second, you can't split the difference because while the wings are in the down position the strap would be at one angle, but while lifted up the angle of the strap would be multiplied by??? because of the shorter distance or amount of strap left. So you will need to keep the bearing very close to the final or up position.
Lou

[RAYVILLIAN]

I have faith in you guy to figure it out.

I'm still trying to figure out how to run a cable through the drop floor so I don't step on it every time I get in the trailer and where to put the crank where it's out of the way.

My normal engineering method is the sleep on it and wake up in the middle of the night thinking about it method.

Gary

[wlooper89]

Although I have read through the thread, I am having a difficult time getting my mind around this. IMHO gas struts should work fine if they are the proper size and position. I would put them inside the trailer if possible. This seems much easier than the contemplated solution.

In my trailer the gas struts achieve a somewhat neutral lift vs. weight of the galley hatch. When shut the hatch stays down without being latched and when raised it stays up. I realize the hatch you have may be larger and heavier, but could not the right size struts handle it? Finding the proper strut size and positions of the attach points on either end of the strut might be difficult. I do not know how to do that but perhaps one of our resident experts could help. This is a not very good photo of my gas strut location, upper left corner. There is a similar strut on the passenger side.
http://tnttt.com/album_ ... c_id=37829

Bill

[wlooper89]

I am thinking there might be a way to experiment with gas strut positioning once the gas strut is on hand. Perhaps with C-clamps try to determine what position works best before final mounting. As far as ordering the right size gas strut, I am clueless and hope someone else has an idea.

Bill

PS My tongue box also has a gas strut and when released it pops the lid up so fast it is a shock to everyone. I have learned to keep my hand on the lid and let it up normally.

[kennyrayandersen]

I'm still trying to figure out how to run a cable through the drop floor so I don't step on it every time I get in the trailer and where to put the crank where it's out of the way.


My normal engineering method is the sleep on it and wake up in the middle of the night thinking about it method.

Gary

You could access the crank from the rear similar to a model T -- the crank part could just be a handle that is removable if you want.

First of all, what the heck are you doing on the computer during vacation, go have some fun. Second, you can't split the difference because while the wings are in the down position the strap would be at one angle, but while lifted up the angle of the strap would be multiplied by??? because of the shorter distance or amount of strap left. So you will need to keep the bearing very close to the final or up position.
Lou

If the normal axis of the roller goes through both the star and end point then it will be out in the middle; hey, I know it works kinematically, but the strap may not stay on the roller (I think the wall could guide it with a little rub strip on the aft edge?), but I think it worth of a small experiment. There is NO doubt that it works with a cable.


Original poster said he didn't want to use gas struts. Since the door weight is pretty high, and we've seen some pretty big force multipliers to operate the door, I can see his point. I'm not saying the strut couldn't work, and in the end it might be better -- this is just an alternative method is all -- it may not even be the best method. Still, there are a lot of pop-up campers out there that are using a similar crank methods albeit with cables inattead of a strap.

[mikeschn]

I think I'll stick with the gas springs.

Mike...

[tech]

JMHO but it seems the cable rollers are placed in the wrong orientation. If they were placed with the axle 90 degrees to the trailer side walls at the very tops of the right and left rear 90 degree wall corners and then the cable ran down to the the lowest point on the hatch wing , IE the point of the wing, they would not have to follow an arc.

The cable and attachment point would be all but hidden by the wing,think of a garage door torsion balance spring mechanism but with the power located remotely.

Using pulleys the pull point could be located anywhere with a simple boat type winch providing the power. The cables would not have to be that robust (less than 1/8")as the hatch from what I have seen is not all that heavy. In fact it is very possible that a pair of garage door cables could be utilized as they already have an eye and ferrule on one end which would slip over a pin located on the wing side panel of the hatch. The cables are used for lifting and lowering not holding.

Sorry for the long post but this intrigued me and it was all clear in my mind even if it came out muddy.

Tech