Between 265 & 485 SQ/FT The 12-Gauge Garage

[bwap]

Nice work, such a great idea!

 

[Stuart in MN]

Nice work. I'm thinking the kids are going to want to use it as a clubhouse when it's up in the air.

 

[jbmatth]

Very cool idea and a great way to maximize available space. What do the neighbors think of your movable tree house?

JB

 

[wssix99]

Using a four-post lift makes much more sense, safety-wise. I'm not documenting this much because I would hate to see someone else try it and have it fail on them. I don't have the training to determine appropriate materials and methods -- I just have my gut 'sense' of what's going to work, which is (of course) a terrible way to build something with important structural issues.

Thanks. You have a really tight space for a typical four post lift, also. If you were to go that route, I imagine you'd have to customize quite a bit and even trim the base plates.

Your frame is slender, and I imagine you could have some problems in an earthquake. You might consider the following additions to provide some resilience:

- Base plates welded to the leg feet
- Cross brace both sides
- Add gussets to the interior angles of the frame (Looking down from the sky, the frame could "twist" like a screw under external loads. Gussets can help the corner welds resist that.)
- Safety locks at height. (Depending on how high you are going to lift, you might also use auxiliary jack stands for the purpose. They could give you backup support in the event of a cable failure and would also provide some additional stability.)

 

[Old Man Roger]

I love the creativeness, and I can appreciate the work to build it.

Being lazy, I would have went with a dedicated ''tow vehicle'' like a ride on lawn mower, or small 4 wheeler.lol A hitch on the front to make backing it out easy. You could leave the tow vehicle hooked up, just pull the trailer in tongue first.

Are you planing on leaving it up?

 

[Jack Olsen]

I'll reply to posts individually a little later. But here's a design challenge I've been thinking about for the past couple of weeks.

The platform will be held up by steel pins when it's stationary. The only time I'd likely suffer catastrophic cable/sheave/structural failure with a big crunch would be while I'm actually raising or lowering the thing. Now, a four post lift uses a ratcheting tooth mechanism to prevent each corner from dropping suddenly, with an electric or hydraulic switch to retract the tooth while the lift is being lowered. I would like some kind of 'catch mechanism' like that. But I'd like it to have the following design features:

1) It's got to be able to catch a 1,000+ pound camper if a cable snaps.
2) Ideally, it would have some 'cushion' to its catching characteristics -- so that its deceleration isn't as destructive as a drop to the concrete.
3) It's got to independently operate on all four corners, since I don't know where the potential failure would be and I would like some redundancy -- if one corner's catch device fails, I'd like the other three to be able to work as they normally would.
4) I'd like it to operate automatically, without my having to remember to engage/disengage it.
5) I'd like the mechanism to be something ready-built and extensively tested, not something I build to mimic an existing device.
6) I'd like it to cost less than a hundred bucks for the whole deal.

Any suggestions? I looked at everything from mountain-climbing gear to variable-length legs that would swing down as the cradle rose. But I landed on something that I think will do the trick. I'll be interested to see if anyone lands on the same place.

 

[PugetDude]

I'll reply to posts individually a little later. But here's a design challenge I've been thinking about for the past couple of weeks.

The platform will be held up by steel pins when it's stationary. The only time I'd likely suffer catastrophic cable/sheave/structural failure with a big crunch would be while I'm actually raising or lowering the thing. Now, a four post lift uses a ratcheting tooth mechanism to prevent each corner from dropping suddenly, with an electric or hydraulic switch to retract the tooth while the lift is being lowered. I would like some kind of 'catch mechanism' like that. But I'd like it to have the following design features:

1) It's got to be able to catch a 1,000+ pound camper if a cable snaps.
2) Ideally, it would have some 'cushion' to its catching characteristics -- so that its deceleration isn't as destructive as a drop to the concrete.
3) It's got to independently operate on all four corners, since I don't know where the potential failure would be and I would like some redundancy -- if one corner's catch device fails, I'd like the other three to be able to work as they normally would.
4) I'd like it to operate automatically, without my having to remember to engage/disengage it.
5) I'd like the mechanism to be something ready-built and extensively tested, not something I build to mimic an existing device.
6) I'd like it to cost less than a hundred bucks for the whole deal.

Any suggestions? I looked at everything from mountain-climbing gear to variable-length legs that would swing down as the cradle rose. But I landed on something that I think will do the trick. I'll be interested to see if anyone lands on the same place.

Jack, I've seen a safety ratchet on movable machinery parts-really simple, it uses a pneumatic cylinder to swing a locking arm out of the way when retracting, it rides the frame up and would engage to catch the load in the event of a mechanical lifting failure. I'll see if I can find a picture.

 

[Bob Heine]

Jack, your price point made me think Junkyard Solution. I'm picturing four inertia seat belt retractors. As long as the frame is moving slowly, they would unreel but as soon as one moves quickly, it would lock. I'm pretty sure those units are rated for more than 250 pounds (1,000/4). I'm just not sure if any of those retractors hold six-plus feet of belt.

 

[Craptain]

Bob, I like your thoughts on that. I was still thinking about it and you already had an answer.

Sent from my SM-G930T using Tapatalk

 

[rlitman]

...2) Ideally, it would have some 'cushion' to its catching characteristics -- so that its deceleration isn't as destructive as a drop to the concrete...

The trick here is in stopping it right away, before it has time to accelerate. The more it drops, the more potential energy gets converted to kinetic.

 

[Jack Olsen]

Well, I don't know if Bob Heine wins the genius award on this -- but he wins the every-bit-as-smart-as-Jack-Olsen award. That's the same thing I came up with, and I had a couple of extras sitting around from when I installed a rear seat in my Jeep. So I tested one of them in place and the belts turned out to be long enough.

A 300-lb passenger in a 100-mph crash isn't something I'd expect would snap a 3-point harness -- and that's 300-lb subjected to something like 92 G of sudden force. So I suspect the weight of this camper spread over four of them will be okay.

The testing (both real-world and DOT) on retractable belts is pretty extensive, and the costs of that testing has been swallowed up by the scale of their use. So it's not like getting mountain-climbing gear where you're paying a lot just for the liability insurance.

I wish there were a way I could really test them, but I don't have a spare camper and a spare lift to do that. I still won't get anywhere near the thing when it's raising or lowering. But for the cost of about $70, it seems like it can't hurt.

With all four bolted in place, I tested lifting the thing to full height today. Can you spot the camper in this picture?

Here's the opposite angle. You can see the inertial reels and belts on the corners.

 

[rlitman]

...A 300-lb passenger in a 100-mph crash isn't something I'd expect would snap a 3-point harness -- and that's 300-lb subjected to something like 92 G of sudden force. So I suspect the weight of this camper spread over four of them will be okay...

My guess is that they're probably easily up to the task, and the little slack at the end is helpful. It gives the camper that tiny moment of acceleration that will get the belt moving fast enough to engage. If it were a tight fit, I'm, not sure it would lock up as reliably.

The concern I have is with UV. I don't think that stuff is designed to hold up outdoors. I wonder if some strategically applied paint would help.

 

[cortina64]

Well done Jack, your ingenuity and engineering skills are amazing!

Warren

 

[kbuhagiar]

This thread is the gift that keeps on giving.

 

[slik560]

From the street, it looks like a skylight.

 

[BlueBomber]

My guess is that they're probably easily up to the task, and the little slack at the end is helpful. It gives the camper that tiny moment of acceleration that will get the belt moving fast enough to engage. If it were a tight fit, I'm, not sure it would lock up as reliably.

The concern I have is with UV. I don't think that stuff is designed to hold up outdoors. I wonder if some strategically applied paint would help.

Re: the UV concern, it looks like they'll spend most of their time in the fully retracted (up) position, so they won't be exposed to much sun.

Another genius/smart ***/tightwad feature. I can't believe I hadn't subscribed to this thread sooner...

Sent from my SM-G950U using Tapatalk

 

[Outlawmws]

Well thought out and well done Jack! Looks good!

I'd bet you can't see that top from a drive by. How much head clearance do you have in the up position?

 

[Jack Olsen]

It's all fun and games until the day I have to explain to the insurance guy how the camper landed on the top of my car.

 

[wssix99]

A 300-lb passenger in a 100-mph crash isn't something I'd expect would snap a 3-point harness -- and that's 300-lb subjected to something like 92 G of sudden force. So I suspect the weight of this camper spread over four of them will be okay.

I would look to swap the belts out for something else.

The webbing is designed to stretch under shock loads, which could lead to tipping or tearing. I also think that most mechanisms rely more on the movement of the retractor mechanism vs. the belt webbing to cause a retractor lock:

I would think some monkey pole jacks could be re-purposed nicely here, but the cost would drive over $100?

 

[Outlawmws]

There is another type with centrifugal latches, and if you pull on the belt too fast, it will engage. possibly they use both for double security, as I know if I'm on the brakes, it can also engage...

 

[Jack Olsen]

Thank you guys -- for at least humoring me on this. I'll repeat: no one should copy me on this one. The downside to a mistake is pretty huge.

How much does the Boler weigh?

I'm going to get an exact weight of mine, now that I'm able to lift it up and set it down on my cornering scales. It's reportedly around 900 pounds empty. We'll see if that's true or just hype.

Very cool idea and a great way to maximize available space. What do the neighbors think of your movable tree house?

No comments yet. I don't think any of them have seen it, though. You really need to know where to look in order to notice it. Even my wife missed it when she came home tonight.

Nice work. I'm thinking the kids are going to want to use it as a clubhouse when it's up in the air.

It's possible that I'll get comfortable with it enough for that. We'll see. I'm adding a switch for the hoist that needs a key in order to operate. I don't want anything to happen that will make me regret this.

Thanks. You have a really tight space for a typical four post lift, also. If you were to go that route, I imagine you'd have to customize quite a bit and even trim the base plates.

Your frame is slender, and I imagine you could have some problems in an earthquake. You might consider the following additions to provide some resilience:

- Base plates welded to the leg feet
- Cross brace both sides
- Add gussets to the interior angles of the frame (Looking down from the sky, the frame could "twist" like a screw under external loads. Gussets can help the corner welds resist that.)
- Safety locks at height. (Depending on how high you are going to lift, you might also use auxiliary jack stands for the purpose. They could give you backup support in the event of a cable failure and would also provide some additional stability.)

The frame is slender, but that's kind of an illusion. You really have to consider the two walls that it attaches to as part of the structure. And since the walls are wood frame construction, they're pretty good in earthquakes because they flex. They're also thick. I had to use 14" carriage bolts to connect to them. And the two uprights on the wall side (which are 1/8"x2"x4") are connected with those bolts to a beam I had to notch into. It's solid wood, almost a century old, and 14" thick. Then there's a second wall I was able to go all the way through that's 90° from the first. With the camper in the high position, there is nothing I can to do produce any wobble in the structure -- even if I grab the most-isolated leg to shake or use surfer-style moves up inside the camper itself.

I have base plates and I poured a concrete footing for the legs that aren't on the driveway surface itself. The base plates are tied in with Tapcons.

On the long side that isn't bolted to the adjoining wall, I have a 6' high x-brace welded in between the two uprights to keep those two legs parallel.

I planned on gussets, although now that I've tried to move the loaded frame and failed, I'm scaling that back from my original idea.

I have half-inch steel pins (with the inset spring-loaded ball) supporting each corner of the load itself once it's raised into position. When I actually saw the pins in action, I decided to add some more reinforcement to the 'ears' that go on either side of each upright. It held fine, but the fact that everything is being held up by some bent pieces of 1/8" steel didn't seem like a great idea, long-term. So I'm going to overlay some side pieces that will be stronger.

I'm also adding some last-chance loops of the wire rope to reduce the consequences of a break where the cables mount with their sleeved loops. My goal is to have some survivability to the whole mechanism, even if any one (or two) components surprised me with a failure.

I love the creativeness, and I can appreciate the work to build it.

Being lazy, I would have went with a dedicated ''tow vehicle'' like a ride on lawn mower, or small 4 wheeler.lol A hitch on the front to make backing it out easy. You could leave the tow vehicle hooked up, just pull the trailer in tongue first.

Are you planing on leaving it up?

I can't pull it anywhere. I simply have no room. Here's how bad the situation was before this lift. I couldn't even take my trash cans out to the street without moving the trailer.

My guess is that they're probably easily up to the task, and the little slack at the end is helpful. It gives the camper that tiny moment of acceleration that will get the belt moving fast enough to engage. If it were a tight fit, I'm, not sure it would lock up as reliably.

The concern I have is with UV. I don't think that stuff is designed to hold up outdoors. I wonder if some strategically applied paint would help.

I hadn't thought about the UV. But I recently replaced the belts in my Jeep which were out in the sun for the past 35 years. They were faded from the sun, but might have still been functional. In any case, these won't be asked to last 35 years.

From the street, it looks like a skylight.

I finally walked my wife far enough away so she could see it -- even from the street, it's not visible -- you've got to go up the hill across the street. I think the fact that it's white and curvy makes it blend with the architecture pretty well.

Well thought out and well done Jack! Looks good!

I'd bet you can't see that top from a drive by. How much head clearance do you have in the up position?

The lowest point on the trailer are the wheels, and they're a little more than six and a half feet up. The rest of the undercarriage is about 84" up.

There is another type with centrifugal latches, and if you pull on the belt too fast, it will engage. possibly they use both for double security, as I know if I'm on the brakes, it can also engage...

These are 'universal' belts, so they don't work with any kind of exterior inertial switch. They're rotary inertial (or whatever it's called). I've jerked them at different speeds and with different initial velocities, and I'm reasonably confident they'll all grab if the trailer drops down.

But then, I hope I never find out if they work.

Here I am, filthy from cutting, drilling and welding in the 90° heat -- up inside the elevated camper. You can see the welder down below.

 

[Old Man Roger]

I can't pull it anywhere. I simply have no room. Here's how bad the situation was before this lift. I couldn't even take my trash cans out to the street without moving the trailer.

AAHH OK! I thought it would only have to be backed out of the driveway on the occasional track day.

Here I am, filthy from cutting, drilling and welding in the 90° heat -- up inside the elevated camper. You can see the welder down below.

I knew you'd go up there..lol

 

[Kriesel]

A little google-foo leads to some seat belt physics:
http://hyperphysics.phy-astr.gsu.edu/hbase/seatb.html

And some laws regarding seat belts:
https://www.law.cornell.edu/cfr/text/49/571.209
"(b)Breaking strength. The webbing in a seat belt assembly shall have not less than the following breaking strength when tested by the procedures specified in S5.1(b): Type 1 seat belt assembly - 26,689 N; Type 2 seat belt assembly - 22,241 N for webbing in pelvic restraint and 17,793 N for webbing in upper torso restraint.

(c)Elongation. Except as provided in S4.5, the webbing in a seat belt assembly shall not extend to more than the following elongation when subjected to the specified forces in accordance with the procedure specified in S5.1(c): Type 1 seat belt assembly - 20 percent at 11,120 N; Type 2 seat belt assembly 30 percent at 11,120 N for webbing in pelvic restraint and 40 percent at 11,120 N for webbing in upper torso restraint.

(d)Resistance to abrasion. The webbing of a seat belt assembly, after being subjected to abrasion as specified in S5.1(d) or S5.3(c), shall have a breaking strength of not less than 75 percent of the breaking strength listed in S4.2(b) for that type of belt assembly.

(e)Resistance to light. The webbing in a seat belt assembly after exposure to the light of a carbon arc and tested by the procedure specified in S5.1(e) shall have a breaking strength not less than 60 percent of the strength before exposure to the carbon arc and shall have a color retention not less than No. 2 on the AATCC Gray Scale for Evaluating Change in Color (incorporated by reference, see § 571.5).

(f)Resistance to micro-organisms. The webbing in a seat belt assembly after being subjected to micro-organisms and tested by the procedures specified in S5.1(f) shall have a breaking strength not less than 85 percent of the strength before subjection to micro-organisms.

S4.3 Requirements for hardware.

(a)Corrosion resistance.

(1) Attachment hardware of a seat belt assembly after being subjected to the conditions specified in S5.2(a) shall be free of ferrous corrosion on significant surfaces except for permissible ferrous corrosion at peripheral edges or edges of holes on underfloor reinforcing plates and washers. Alternatively, such hardware at or near the floor shall be protected against corrosion by at least an electrodeposited coating of nickel, or copper and nickel with at least a service condition number of SC2, and other attachment hardware shall be protected by an electrodeposited coating of nickel, or copper and nickel with a service condition number of SC1, in accordance with ASTM B456-79 (incorporated by reference, see § 571.5), but such hardware shall not be racked for electroplating in locations subjected to maximum stress.

(2) Surfaces of buckles, retractors and metallic parts, other than attachment hardware, of a seat belt assembly after subjection to the conditions specified in S5.2(a) shall be free of ferrous or nonferrous corrosion which may be transferred, either directly or by means of the webbing, to the occupant or his clothing when the assembly is worn. After test, buckles shall conform to applicable requirements in paragraphs (d) to (g) of this section.

(b)Temperature resistance. Plastic or other nonmetallic hardware parts of a seat belt assembly when subjected to the conditions specified in S5.2(b) shall not warp or otherwise deteriorate to cause the assembly to operate improperly or fail to comply with applicable requirements in this section and S4.4."

To Jack's point, seat belts should do the trick just fine considering the development put into seat belts by automakers.

 

[Jack Olsen]

That's good to know. Thanks.

As an aside, here's my 'home project tip' for when you decide to do something that's big and a little ridiculous. My wife was understandably on the fence on the wisdom of putting a big camper up above our heads. The spot I'd chosen for it was about as out-of-sight as is possible on an eighth of an acre plot. But I knew the levitated camper would be visible from our patio, which is on the other side of the wall that runs along the driveway.

We can grow vines or something in that spot long term to make the thing less visible. But one of the first purchases I made was an Ebay remnant of some Sunbrella fabric. I knew that the less my wife saw of the project as it went up, the better. So I obscured it right from the beginning. Here's a picture of the camper up in the air, which you might miss because of the leafy pattern of the fabric I chose.

 

[elguappo]

This is wisdom here.
Keep the wife happy, continue on with questionably engineered projects.
;-)

 

[Nolift911]

Holy HOA batman!!!

I think at the first sign of a "structure" out of the norm I would have been reported...

 

[wssix99]

I have base plates and I poured a concrete footing for the legs that aren't on the driveway surface itself. The base plates are tied in with Tapcons.

lol It's like a TV cooking show where all the vegetables are peeled before the chef walks into the kitchen! It looks so easy that way. There's a little Hollywood magic behind this project. It looks like it went up so fast!

 

[Jack Olsen]

lol It's like a TV cooking show where all the vegetables are peeled before the chef walks into the kitchen! It looks so easy that way. There's a little Hollywood magic behind this project. It looks like it went up so fast!

12 days, pretty much full-time. Before I got started I had everything I needed delivered (McMaster-Carr, Zoro, Amazon). The only thing I went out for was the steel. But even with everything on hand, it took me a surprising amount of time to put together.

The more time-consuming part was figuring out how I was going to do it. Being a non-engineer, it was a challenge for me just to work out how pulleys (sheaves, I learned to call them) can be put together to half the load by doubling the amount of rope used to move a load. Basic stuff to someone with even a small amount of education in this area -- but most of it was new to me. How much to reinforce the different components was something I put a lot of thinking into (not a lot of knowledge, but thinking at least). It's hard for me to understand something mechanical without seeing it in front of me.

But it was in the nineties most days and I was out in the sun for most of it, which was pretty brutal.

Still, I'm glad it's done.

 

[Craptain]

First mention of this project was on 15th. Now he says 12 days. Methinks Jack already had this more or less worked out before he ever asked any questions here. More like validating his plans than really needing help.

What say you Jack?

Sent from my SM-G930T using Tapatalk

 

[Brian R]

12 days, pretty much full-time. Before I got started I had everything I needed delivered (McMaster-Carr, Zoro, Amazon). The only thing I went out for was the steel. But even with everything on hand, it took me a surprising amount of time to put together.

The more time-consuming part was figuring out how I was going to do it. Being a non-engineer, it was a challenge for me just to work out how pulleys (sheaves, I learned to call them) can be put together to half the load by doubling the amount of rope used to move a load. Basic stuff to someone with even a small amount of education in this area -- but most of it was new to me. How much to reinforce the different components was something I put a lot of thinking into (not a lot of knowledge, but thinking at least). It's hard for me to understand something mechanical without seeing it in front of me.

But it was in the nineties most days and I was out in the sun for most of it, which was pretty brutal.

Still, I'm glad it's done.

Just back from vacation in UK. Tower of London has a pretty decent exhibit / demonstration on how castle builders used pulleys to raise huge stone blocks for construction.
Cool stuff-well done, Jack

 

[Jack Olsen]

I sketched out the idea on a trip to Chicago for the 4th of July. It's been in the works since then. When I posted my 'to do' list on the 14th, I was already well underway. I already had six items checked off.

The new video for it only took a few hours this evening. It would have gone even quicker, but my six-year-old had some definite ideas about how it should look and sound.

(Click on the image to see the video.)

 

[Lookin4'67Galaxieconv]

Jack, that trailer is a great size. It's a great upgrade from tent or pop-up camping because you can stop at an overlook or roadside picnic park and have lunch and also have zero setup time in the rain. Our much heavier and cruder trailer was about the same size and our family of four used it until I was 12 and my brother was 14. Our trips lasted about 75 days so the extra two feet came in handy. Not being air tight (not even close) meant living with a lot of dust at times (like 2,000 miles of unpaved Alcan highway).

Looks like a Serro Scotty Sportsman. We camped out at the beach with one of those in the '70s.

I'm debating getting one of those now, vs. a newer camper.

 

[Grizz1963]

Just Brilliant

Well done Team !!

 

[Boosted1]

Nice video. You have skills.

 

[jbmatth]

Great video Jack, and well done all around.
JB

 

[kbuhagiar]

On a completely unrelated note, I can't believe how fast the kids are growing...

Have I really been following this thread for over eight years???

Seems like just yesterday that I discovered the 12-Gauge Garage...

 

[yates]

Only thing I can think of on the camper might be a way to secure the trailer to the lift so that it does not bounce off due to a jerk or anything that would allow it to bounce (if that makes sense). I would hate to see the frame stop but the trailer not. Maybe a strap point from the frame to the trailer similar to how you strap a car down although it would need to be nearly as tight.

 

[stonesg]

Speaking of securing... Is there any possibility of high winds that the combination of wind, the walls, gate and the shape of the trailer might make it lift off the cradle?

TG

 

[Jack Olsen]

yates, I agree with you -- and that's on my 'punch list' still. I'm going to add a thing to the rear cradle that interlocks with the bumper so the whole assembly can't slide in a seismic event. For now, I'm using a big-*** C-clamp to eliminate the possibility of lateral movement.

 

[Jack Olsen]

yates, I agree -- and that's on my 'punch list' still. I'm going to add a thing to the rear cradle that interlocks with the bumper so the whole assembly can't slide in a seismic event. For now, I'm using a big-*** C-clamp to eliminate the possibility of lateral movement.