Tri-axially loaded carabiners for autobelay mounting at Rocksport in Reno, NV

I'd be interested in actually hearing what kind of load they do generate. There is a moment of free fall and then speed is drastically reduced. I'm sure Head Rush has some documentation.

While I agree in general that these devices' clutching systems definitely bring the force down considerably, I feel like it is really naive to assume that these things are so magical that a 220lb guy just dropping off at the top of the route (sometimes even climbing above the device slightly) generates little more force on those biners and unit than body weight. I would go out on a limb and say that given the right scenario, it could be a lot more than that.

I'd be really interested to find or hear real data on the forces that can be generated by one of these things, both by proper and improper use. The manual for the device states that the unit needs to be installed to an anchor point that can withstand 20kn:

"Anchor point must be capable of withstanding a
minimum load of 20 kN (4400 lbs) in expected
direction of load application. All connectors, hooks, D-rings and shackles used to
mount the TRUBLUE Auto Belay must meet a
minimum breaking load of 20 kN (4400 lbs) and
comply with the relevant standards. "

Well i think everyone can agree its really bad practice

The other thing to keep in mind is that they havent failed ... Everybody including fatty newb yankees have flailed and been up those things over and over again

And unless its been swept under the rug theres not been a failure of even a single point ... Which just goes to show you the ridiculous margins built into climbing gear

Its bad ... But it aint killer .. So far

;)

On a side note, anyone know how the braking system on the autobelays works? Does it use a clutch pack, centrifugal clutch or something else all together?

20 kN wrote:On a side note, anyone know how the braking system on the autobelays works? Does it use a clutch pack, centrifugal clutch or something else all together?

They use eddy current braking.

What are eddy currents?
Eddy currents happen when you move non-magnetic metals through a magnetic field

What is eddy current braking?
Eddy current braking uses a phenomenon called electromagnetic induction, where motion between a magnet and non-magnetic metal causes a force opposing the motion between the two objects. As a result, kinetic energy, which is movement, is converted to thermal energy, which is heat. This braking happens entirely without contact. When the conductive material in the magnetic field is still, no reaction occurs. When the conductor moves while in the magnetic field, a magnetic field and eddy currents are generated within the conductor that opposes the direction of the current of the magnetic field of the permanent magnet to create the braking effect. This is called an “eddy current”, because the current doesn’t travel in a straight line. The induced current swirls within the conductor, like eddy currents in a river.

How is eddy current braking used in our devices?
In our devices, a retraction spring winds the webbing into the device. When force pulls the webbing out of the device, aluminum rotor arms are sent spinning into a magnetic field. This creates the eddy currents. These currents control the braking force and, thus, the speed at which the spinning occurs. This, in turn, controls the speed at which the webbing comes out. Our eddy current braking system is self-regulating. This means that the braking resistance automatically adjusts itself to provide consistent braking across a wide range of participant weights.

That is a badass explanation, Patrick Mulligan. What a cool device. Why fuck it up by rigging it wrong. Anyone from the gym gonna reply to this thread?

disclosure: I work for Head Rush Technologies the manufacturer of the TRUBLUE Auto Belay.

Here is an admittedly salesy video, but it explains how the TRUBLUE works (since this is on topic). There are no clutch bearings in the device. The 20kN rating comes from the Climbing Wall Associations minimum load requirements for belay bars. I'm not in a position to release load figures, but I can say that our free fall device the QuickJUMP uses the same technology and only requires a 10kN anchor requirement (there is also a major safety factor included). The nature of the magnetic braking GREATLY reduces the load.

youtube.com/watch?v=bkm61bi…

To be clear I'm not commenting on the anchor set up that started this thread.

Cheers,
-Micah

Micahisaac wrote:To be clear I'm not commenting on the anchor set up that started this thread. Cheers, -Micah