Posted Thursday, October 10, 2002 6:21 AM | Contributed by RideMan
A flaw in the design of a ride at the Ohio State Fair was to blame for one of its cars falling about 15 feet, injuring two men in August, according to a final report released Wednesday. The Ohio Department of Agriculture, which is responsible for inspecting amusement rides, said that cracks caused the welded metal to snap where the car joined an arm of the Re-Mix.
Read more from AP via The Akron Beacon Journal.
--Dave Althoff, Jr.
Why would there be a seam in the middle of the tube?
I rode one of these rides and wasn't too impressed, but now that this has happened I think I'll be staying away from them for good. Orbiters which seem much sturdier are my ride of choice between the two. Orbiters go much faster with far more Gs.
If that really is a butt weld between 2 piece of tube, I'm like Ride_Op, I don't quite understand why it is there rather than using one piece of tube then welding it to the block. The only thing I can think of is that the want to be able to inspect the fillet weld of the tube to the block inside and out since it can't be X-rayed well, then did the blind weld as a butt so that it could be x-rayed. The newspaper article makes it sound like there was also an internal corrosion problem.
The whole thing without further details makes me wonder if this was really a design error or a fabrication error. Properly make between 2 pieces of tube, the butt weld should be as strong as the tube. However, if things aren't done right it can be much weaker especially in fatigue which there would lots of. Then again there is the mention of corrosion.
This sounds suspiciously like the (in)famous Spider sweep crack that propogates from the end point of a pair of welds on the sweep, and starts on the inside surface of the tube.
I tried to determine whether there was a similar seam on the KMG rides at the Ohio fair this year, but I couldn't see that tube on the KMG ride because there is a reinforcing gusset plate wrapped around that tube on the KMG rides. At least I think that's what I'm seeing in this photo.
--Dave Althoff, Jr.
There are two different types of tubing, seamless, and seamed. Seamless tubing is extruded,and if I recall correctly, seamed is rolled. The seam is fused shut in the manufacturing process. The latter is less expensive to make than extruded, and in some cases they can be interchanged with the seamless in certain applications. Apparently this isn't one of them.
Many of the smaller European ride builders have components built by the same fabricators, thus sharing certain subassemblies.Thus KMG and Tivoli using the same seat assemblies and other components is not unusual.
Thing is, that weld would have a starting and ending point somewhere along the circle, and the point where the start of the weld and the end of the weld meet would be an inflection point in the weld. My guess is that the overlap point of the weld is probably where the crack started. I don't know that; it's just a guess at this point. But it's consistent with what I know of Spider sweep cracking, and this sounds like a similar problem.
--Dave Althoff, Jr.
As Dave has pointed out many times, it varies from state to state and in many cases fairs and carnivals are better regulated than parks.
"This just also proves my point that fair rides are not as well made a stationary rides."
Really? I would advise you to check out rides from KMG and Mondial before saying that every ride made to move is inferior. You should also contact several parks and tell them they have dangerous rides. For instance, all of these parks operate dangerous portable rides:
Myrtle Beach Pavillion- Huss Top Spin, Mack Petersburger Schlittenfahrt, Mack Calypso, Zierer Wave Swinger
Cedar Point- Schwarzkopf Wildcat, Mack Calypso, Schwabinchen and Matterhorn
Knoebels- Zamperla Power Surge, Dartron Downdraft, Eyerly Roll-o-Plane, and Sellner Tilt-a-Whirl
I am sure most of these manfactuerers would be insulted at the insinuation that they build rides to lower-quality standards when building for a carnival or indepedent operator as opposed to a park.
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