On February 24, 2018 at 12:11, cma said...
I don't see why not
Here's why not:
On February 24, 2018 at 12:18, Ernie Gilman said...
A ceiling mount tends to hang plumb because the weight is more or less centered under the pipe. An upside down application will be the reverse. The TV will tend to want to fall off to the side because it's above the mounting point. Your challenge is to stabilize things so that doesn't happen.
The problem is called a lateral load. It's hard to find much about this kind of load short of huge sideways forces on buildings, but look it up and think about the forces that are shown.
As an example, if your TV is off perfect balance such that, say, five pounds of sideways force is exerted against the mount at, say, 18 inches up; and if the base is 4 inches across; the lever thus formed translates that into an upward pulling force on the mounting bolts of 5 pounds times 18 inches divided by 4 inches, which is 22 1/2 pounds. Now that I've done a calculation that probably puts us in the ballpark, it doesn't look like much force. Just be aware of it and make the mount plenty beefy.
On February 24, 2018 at 19:10, Archibald "Harry" Tuttle said...
Tried that upside down ceiling mount before, but gravity didn't cooperate.
On February 25, 2018 at 00:26, AZCS said...
How about something like...[Link: chiefmfg.com]
The base on that is not very large, but if the TV's mass is pretty well centered above it, the base should keep the TV from falling or angling to the side. If it's possible to use lag bolts, DO NOT
do so! Use nuts and bolts, with fender washers on the bottom so that pullout forces can't make the nuts sink into the wood.
On February 26, 2018 at 10:33, tomciara said...
I'm ordering a ceiling mount. It comes with a 36" extension, so I also ordered 6" and 12" extensions, along with a couple adjustable extensions, hoping to get the height I am after.
Looking at the numbers I cited above, if the TV exerts a sideways force of 5 pounds at 36 inches up, and the base is 4 inches across, the resulting lever exerts a pullout force of 5 pounds times 36 inches divided by 4 inches, which is 45 pounds.
On March 3, 2018 at 10:18, FreddyFreeloader said...
Gotcha. An aftermarket tabletop stand with adjustable also height comes to mind. Maybe you have a plan but I’m wondering if an upside ceiling mount will want to stay straight with such a small base plus the fact that normally it counts on gravity to stay straight.
In news related to holding a mass up and plumb, take a look at this article: [Link: blogs.dailybreeze.com]
about an AM broadcast antenna in the Los Angeles area. It had three or four sets of guy wires that pulled down and out on the antenna, adjusted to hold it totally vertical. Somebody cut ONE TURNBUCKLE
on ONE WIRE and the thing "collapsed like an accordion."
You can't just take a hanging TV mount and turn it upside down.