I worked as a line mechanic , twin post as described . The mechanic next to did the mistake of handle not in the neutral position off to lunch . On return Chrysler 300 , front bumper smashed his tool box rear axle remained on the cradle . Bent the frame on the ole barge . We were no longer allowed to empty the shop for lunch . It was done in shifts .
That is hard to look at. It makes me wonder if they didn't have the deck down on all the locks. I know on mine if the floor isn't even the locks will have to be lowered until they are all down or you have adjust the cables on all four corners.
It appears to be inside a building, so an asphalt floor would be unusual. Maybe the roof I see in the background is a temporary structure in a parking lot? (Off topic: when I was a kid, a local gas station had a single post lift that was outside. The post was kind of rusty, so the mechanic was supposed to wiggle the car when letting it down so the post wouldn't stick and the car would come back to earth smoothly. I was watching one time when they didn't...they just opened the valve and nothing happened, until the car dropped about five feet all at once. It was a real test of the suspension.
I just bought a four post lift to make room for another car in the barn. The guy I got it from stored a Hudson pickup on it without it lagged to the floor. I’m putting a Shoebox on it and lagging it to a real good concrete floor. This thread is timely and convinces me it’s right to anchor it……..Mark
Not all 4 post lifts require or need to be anchored to the floor. Higher quality lifts designed for movement on caster wheels certainly don't.
Interesting... I followed a truck/trailer that had an assembled 4 post on it home one day about a week and a half ago...also in OK. Looked pretty sketchy to me, it was pretty floppy going down the road
Friend recently sold his 4 post lift; borrowed a set of wheels, and rolled it down to another garage in the complex, same way he did when he bought it used a decade or so back. We used the lift for several car builds and lots of normal repair work over those years and as much as I can remember there never was a hint of instability even tho it was never bolted to the floor. The lift had a manual lever for the locks and we always made sure the car was on the locks and not hanging on the cylinder and cables.
I bought a 4-post maybe 8 or so years ago. I know lots of folks don’t anchor them down, but grabbing ahold of mine once all assembled, I was glad that we poured a yard of concrete under every post that I ended up anchoring it to. The stability between anchored and not was night and day. It might have been fine, but I wasn’t taking chances with a couple teenage boys and their friends using it regularly.
I had a 4-post probably a lot like this one at home for a year or so. It came with a wheel setup where you raise the lift, set the wheels in place, then lower it back down and it leverages itself onto the wheels for rolling around. I only used it for storing extra stuff in my garage with a high ceiling and never for working underneath. It did seem pretty sketchy. If it wasn’t setting in the right spot one of the locks would hang up when you tried lowering it back down. Sold it once I didn’t the extra space.
Easy to condemn the lift just from the picture after the failure, but we really need to know the exact situation that caused this catastrophic mess. Obviously many 4 post lifts in operation without incident.
Hmmmmm ... do you lag the legs to the concrete floor or will the addition of the lag holes in the concrete weaken the floor right where it needs strength? Should the concrete floor be dug up where the posts will sit and legitimate footings poured before lagging? If I had one I'd want it lagged in place but I'd also want to know the floor I'm lagging it to is up to the task Always the worrier, I wear diapers both inside and outside my pants Can never be too careful (helps to muffle farts too). Edit: Jeeze, take too long typing and someone sneaks one in before you
The pictures are out of order. The lift looks to have been partially removed when the first shot was taken, since the front left post (and more) is no longer in the picture. The second and third pictures seem to show the deck hasn’t collapsed on the posts, ie it’s still fully extended on the posts and the locks appear to be in place. I do agree that the way to get in trouble with a four post lift is to lower it without fully releasing all four locks, due to improper setup or an inattentive operator. I have seen other “failure” photos where that was the likely scenario. Here, with all the activity in the area, I wonder if the exhibit wasn’t involved in a forklift accident. I guess we’ll never knot. The building appears to be a temporary structure, so a failure of the asphalt as someone suggested could be possible. I don’t see anything in the photos to support that theory, though. Without better photos of the other components, rather than the aftermath, we’ll never know. The way portable lifts are designed, the car/ramps have to be fully lowered to lift the legs off the ground so it can be moved, so that scenario is definitely not the cause. I have two Advantage lifts, both with project cars stored on them in the elevated position, and the legs not bolted to the slab. Those lifts are rock solid, and much safer than my two post lift as far as stability goes.
I also have an Advantage lift that is not bolted to the floor. It is very stable even with my 49 Buick on it up in the air. Even if the hydraulics failed it would only fall about 6 or 8” to the first safety lock.
A great stability improvement. Since the bottom plates warp when welded to column they give you shims to take out any unevenness if you bolt down which I didn't want to do. They will also creep around some as you use lift. I welded the provided nuts to the plates and used the cut down bolts as feet jacks to get columns plumb [I am anal so I glued levels to the columns] and no rock. Then I drilled a hole [5/16-3/8] in center of mounting plate and down into the concrete floor about an inch, dropped a bolt in and no rock/creep.
That sure sucks for the car, lucky no one was hurt. Lots of ways a lift can fail. Everyone worries about floor jacks failing but very few worry about a lift. I’ve see a hydraulic failure where one side started going down while the other was going up. I’ve see a lock not release allowing one side to drop while the other stayed down. I’ve seen a lift most of the way up drop the car to the ground. And I’ve seen a car roll off a drive on lift. several friends have lifts in residential garages on 3” concrete floors . These days you can buy a lift pretty easily and install it yourself. I’m surprised this doesn’t happen more often.
The one that crashed looks exactly like the one I just bought with my new property. The PO said its new, costs 6500, rated at 9000#'s so he could lift his diesel dually. I've looked for a brand name but haven't found one. Genuine Chineseum I suppose. It has the dollies to move around when empty, which I hope to do as I'm not sure yet where it will live. Read that as building too small to house all my junk at 42x48. Never used it yet as its still a construction site. Better look again for a brand name.
https://www.twinbusch.de/twimg/uk/c...ch_fundamentplan_4-saeulen-hebebuehnen_en.pdf Simpsons Set Epoxy for Concrete dowel anchor bolts Lager beer is after the concrete is poured
Too many times, I have seen people drill anchor holes, drop in some Red Head anchor bolts, then set the column over them and tighten the nuts. It usually results in a gap between the concrete and the base plate and gives the column the opportunity to move. The picture below is the way that columns were leveled back when I was setting them. To my knowledge, it's still being done this way. It takes just a few minutes and four more nuts under the base to get the columns plumb. The non-shrinking grout between the base plate and the floor eliminates any movement.
That decking it was on is pretty slick compared to concrete, and not a good thing to have under the bases of a lift! I have it in one of my shops and even jacking my cars up with the small jack on the decking can occasionally shift and give me a scare. I now use a piece of 3/4" plywood with sheetrock screws just poking through the plywood under my jacks to maintain stability under loads and not have the jacks shift.
Better to not even use redheads or flushells for this. I prefer stud anchors that can be easily drilled and anchored right through the base holes. And they come in numerous lengths so depending on slab thickness and base thickness you can drive them in to maximum depth and as you tighten them they get tight in the hole.
The shop I worked in back in the early 70's had a lift like that, we had the same thing happen at lunch time the rear post drifted down when the air pressure bled off . It had a 65 or 66 C10 pick up on it at the time and the controls were in the floor in the front of the sliding post. Owner after a few words reached in the hole with a broom handle and let it down made some strange noises and had a scrape or two more on the already mangled rear bumper but otherwise was no worse for the incident.....
Interesting. If I’m looking at it correctly all of the weight of the column is sitting on the four studs? Would those studs not have a tendency to dig into the concrete?
I mean.... while said In a joking manner I totally would rock it. Lack of Bondo shards after the incident tells a lot of how clean the build was
It was said the building is actually one of the tent structures put up for the auctions over the top of an asphalt lot. On another note I do know of several people with 4 post lifts that are being used regularly without being bolted down and have never had issues.
If I understand your question correctly, the bolts in the picture are long anchors set in the concrete with the threaded end of the anchor bolts exposed several inches above the concrete surface. After the concrete sets, a nut is run down on each anchor bolt that allows you to set and level the column. After the column is level, another set of nuts are run down to hold the column in place. The weight of the column bears on the non-shrinking grout which in turn transfers the column weight to the concrete pad or pier. It's common practice on steel structures. @JD Miller 's example in post #51 works well also, if the concrete is thick enough to take longer bolts. The bolts in the picture look to be approximately 8" long, so the concrete should be that thick at minimum. You have to work pretty quickly using epoxy and the holes should be clean of dust. Anchor bolts set in place ready for the concrete pour.
Word around the beer keg is, after the show, someone was dismantling the lift and forgot there was a car on it. It appears they got one leg done then ... quit before they could get fired Too soon?
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