Restraint testing and weight limits

Saturday, April 5, 2003 10:37 AM
Can anyone (Rideman) that knows for certain tell me how restraint systems are tested and what the theoretical weight limits are for rides like impulses and flyers? My wife loves rollercoasters almost as much as I do, but refuses to ride anything that hangs you from your restraint for more than a fraction of a second. She has this fear of the restraints failing. Any real help would be appreciated. Thanks, J.C.

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Just a couple of G-Force junkies!

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Saturday, April 5, 2003 11:45 AM
If anyone has any info or links to sites that explain how restraint systems for most rides work I'd sure like to see it.

On coasterquest they had a "how it works" page up but they never got around to finishing the page on how lap bars work so if Rideman can put something like that on his site I'd certainly like to read it.

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Saturday, April 5, 2003 11:47 AM
Well, I do not know the answers to your questions. But tell your wife, the Intamin Impulses are a hydraulic (sp?) system, so it is really hard for them to fail. I believe the default is to be closed. Also, they have a safety strap/belt. For added safety.

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Rob


"Some people spend an entire LIFETIME wondering if they made a DIFFERENCE. The MARINES don't have that problem." -President Reagan 1985

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Saturday, April 5, 2003 11:47 AM
You'd probably be best served by asking PTC or Premier how they test their equipment. The weight standard, though, is 170lb, as given by the ASTM.
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Saturday, April 5, 2003 12:09 PM
I can't give you an exact weight limit, but I am sure that the B&M flyers are equipped to hold more weight than you could possibly fit into the seat in human form.

And although the "average" weight of a person is 170 lbs for design purposes, it's my guess that any kind of restraint is designed ot hold much more (at least 2X) than the largest guests it will probably see using it.

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Is that a Q-bot in your pocket or are you just happy to see me?

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Saturday, April 5, 2003 12:41 PM
The vekoma flyer's have a maximum weight restriction of 250lbs.
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Saturday, April 5, 2003 2:54 PM
When it comes to direct safety systems such as restraints, they are redundantly overbuilt. B&M uses a double ratchet design in their other roller coasters. Each ratchet device is more then enough to restrain a rider alone but they use two. In most cases, they also use a belt that is strong enough to prevent the restraint from opening. I've heard that the belt is just a measuring device and it'll break if the other restrints fail. From my own experince, that has proved not to be true. I'm tall, so the restraints push down on my sholders. When I unbuckle the belt the restraint moves up about an inch.

I can see why you wife gets that feeling, but the truth is that the restraints are very important to the safety of the riders and not overlooked. While the actual restraints are tested in various ways, the chances of them failing is very little. I don't think any deaths where caused by the restraints that failed mechanicly.

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Saturday, April 5, 2003 3:28 PM
First of all, the Intamin hydraulic lap bar and shoulder bar used on the Giant Drop, Volcano, the Superman coasters, Millennium Force, rocket coasters, Impulse coasters, and just about any other recent Intamin ride, is described, complete with a schematic diagram, in the Dragster technical article I wrote for Walt Schmidt's "Virtual Midway". The implementation is slightly different, because of the difference in direction of operation, but Intamin uses the same system for both lap bars and shoulder bars. It's worth noting that the system is dual-redundant, in that each seat has two independent cylinder arrangements, either one of which would be enough to hold the bar closed.

Second, Wolf mentions the ASTM standard of 170 pounds. That isn't completely true; the standard for estimating passenger weight is the greater of 170 pounds OR 12 pounds per inch of width at the hip. So a Zierer Wave Swinger with its 16" wide seat would have to be built for 192 pounds, and a Chance Yo-Yo with a 22" seat would have to be built to support 264 pounds. I can tell you from experience that at 250 pounds I found the Yo-Yo seat to have ample room in it. Obviously these rides are built to higher safety factors; at 250 pounds I can also tell you from experience that I fit quite nicely into a Wave Swinger seat as well.

(by the way, the last time I checked I was down to 238 pounds. Nyah.)

Most ride restraints are unnecessary, excessively overbuilt, or sometimes both. That is, if a restraint is necessary, it's generally excessively overbuilt. Multiple locking systems, and backup devices are extremely common. The B&M shoulder bar, for instance, uses four independent spring-loaded locking pawls. The Arrow looping coasters used (don't know if they still do...) a hydraulic locking cylinder with a set of ratchet teeth on the bottom of the rod. I forget the standard for automotive-type safety belts (something on the order of thousands of pounds of breaking force) but those are used as backup belts on an awful lot of ride restraints these days.

The restraints are the one part that gets checked on each and every ride cycle, with the result that actual catastrophic failures in operation are extremely rare. And most of the time a partial failure won't kill anybody.

--Dave Althoff, Jr.

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