Ordered A Lift

Iowa 409 Guy

Well Seasoned Member
Supporting Member 15
I would think it is stress from the towers trying to tip in toward the car. The stress on the anchors would be more of an angled pull on the floor, not straight up or down, just my observation anyway.
I would think the fulcrum point changes as you go up. Kinda like putting a weight on a stick close to you, and then moving it outward. Same going up, weight transfers towards the center.

I haven't looked at many lifts yet but if a person has the height, having a hoist with a cross bar at the top would take these 2 senarios out of play.
 

Tooth

Well Known Member
Supporting Member 3
I have to admit that I have both a 4 post Bend Pak lift in my garage. My MaxJax presently resides outside uninstalled, because there is no room for it inside. Too much junk, clutter and cars!View attachment 72234

How long have you been feeding that parking meter so your lift can stay parked there?:laugh:rollI have a long bed pickup and a trailer I would be happy to come up and do some select picking of my discretion to help you clean a place out to install your lift.:browJust trying to help:dunno
 
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Iowa 409 Guy

Well Seasoned Member
Supporting Member 15
I would think it is stress from the towers trying to tip in toward the car. The stress on the anchors would be more of an angled pull on the floor, not straight up or down, just my observation anyway.

I was just thinking of ways to install a lift even if my floor is not thick enough for their recommendations. The first thing that comes to mind is that the manufacturer is going to cover his a$$ by going overboard with thickness. How many people ever lift the max weight limit anyhow? I wouldn't have a problem placing a 4X4 foot piece of 3/8" or 1/2" steel plate down and making the footprint much larger and then bolt the lift to that. I don't want to be unsafe and get crushed by the Crusher, but I can't see a problem using a plate.

It wouldn't be the first time I engineered something out of the box. I've been building things "quarry tough" all my life. We had a vibrating grizzly feeder on a primary impact breaker years ago. You dug shot rock in the pit and dumped it into this feeder. The rock fell 6-8 feet onto the cheesy light weight 3/8" floor of the feeder. When a rock the size of 2 footstools repeatedly hits the floor it does some damage. The floor wasn't much over a year old and needed replaced because it was not heavy enough. I called the dealer and talked about replacement parts. I wanted something thicker that would last. I wanted to use at least 5/8" thick steel. The guy said he'd check with engineering. He got back to me and said that 5/8" would be too heavy and would affect the vibration. I said ok, and put a piece of 3/4" plate in there. It worked like a top. How in the hell could a 3/4" affect vibration when you are dumping 10 ton buckets of rock on the plate feeder. The key to success was i didn't tell the feeder, and it didn't know the difference.
 

JED

Well Known Member
Supporting Member 5
Thinking out loud here, I believe it might be the down pressure exerted on the towers as the car goes up. Would the pressure also be the same regardless of the height you choose to elevate the car?? For example, would the downward pressure, when you have the lift locked into the height you want and stable, be the same regardless if 4' high or 6' high??

I would expect it has more to do with the "moment arm" of the lift when it is raised with a load on it. I would think that the tendency of the lift posts to pivot with a slightly off center load would be more of a concern than the direct downward force applied directly in line with the vertical posts. Every collapsed 2-post lift that I have seen is because one (or both) of the posts pivoted, bringing the whole load down. I assume (because I have not seen it recorded anywhere) that both the thickness and PSI of the concrete floor (as well as the length of the hold-down bolts) are to resist this "pivoting/twisting" action of the posts when loaded. My Rotary 2-post 10,000 lb lift also required that I needed a minimum mounting pad of 4' square x 6" deep concrete section under each post, with a 3,000 psi minimum and bolts torqued to 150 Ft-Lbs minimum.
I would imagine that Jim's shorter lift has a lower requirement due to the lower lift height and weight capacity giving a resulting smaller moment arm of the lift posts.

Jim: Congrats on the new lift. They sure beat crawling around on the floor.

John
 

scott hall

Well Known Member
Supporting Member 2
Dave the two post 9000 lbs lift I have has the beam on top and it’s structural. Also caries cables and hyd. The top stop switch is adjustable for height so you don’t crush top of vehicle. I keep angle finders on the post to check for movement when load is going up and down. Never moves enem with 1ton dialysis diesels.
 

Carmine

Well Known Member
Supporting Member 10
Dave the two post 9000 lbs lift I have has the beam on top and it’s structural. Also caries cables and hyd. The top stop switch is adjustable for height so you don’t crush top of vehicle. I keep angle finders on the post to check for movement when load is going up and down. Never moves enem with 1ton dialysis diesels.
My lift is similar. Rated at 9000 lbs. Before buying it, I had the choice between the towers being bolted together at the top via a piece of structural steel which also carried the cable and hydraulic lines, or have same on the floor with steel covering them. A speed bump if you will. To me this was a no brainer. Right or wrong, I chose to have the channel steel mounted at top. This thickness if probably about 1/8". Maybe a little thicker. My thinking was exactly as mentioned in a thread here. When raising a car, the two towers can't be helped by pulling in towards each other. I think it's just a natural reaction to movement. That's why it's so important to mount the towers properly. I think the towers joined together at the top with steel, helps with the stability of the entire lift. Just my thoughts, Carmine.
 

Jim Sullivan

Well Known Member
Supporting Member 10
Dave, have you given any thought to going with a four post lift? I wonder what is required as far as floor thickness? As the load is spread out and some of four post lifts I don't think need to be bolted down??
 

1958 delivery

Well Known Member
Supporting Member 2
As stated earlier, the floor requirements is for prevention of the anchors from pulling out, not the weight of the lift pushing down. 4" concrete will handle the weight easily but may be weak in regards to anchors pulling out, probably over kill. The wider the 2 post lift is, the greater the force to pull the posts inward

. A 4 post is secured all around so no issue with the posts collapsing inward or outward
 
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