head and neck safety
10-14-2010 | 04:17 PM
#91
Three Wheelin'
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From: Orlando, FL USA
The wings or epaulets have always been in question. They do assist in keeping the belts on the device if the belts are not installed strictly according to instructions. Some chassis manufacturers, most notably formula cars, have the shoulder straps mounts built into the chassis and are typically wider than recommended. Most cases, because of the proximity to the body, this is not that much of a big deal. As a matter of fact, the 2" wide straps work well. Not because that is the approximate width of the channel on top of the device but because of the mount width. If the belts are mounted properly, the outside edge of the shoulder straps do not even touch the epaulet.
The 2" HANS specific harnesses were designed for an issue that is probably not an issue if harnesses are mounted properly. None of these harness manufacturers worked with HANS while I was there for approval. HANS approved the 2" wide shoulder straps because they were either SFI or FIA approved. To my knowledge, HANS still only tests with 3" wide straps.
As Professor HANS mentioned earlier, NASCAR investigated around 4,000 crashes in their division and have never had an issue with the belts coming off the device. Of course, they have much stricter tech inspections. They don't just check for current dates. In the 3 years I did track support, I never found an issue of the belts coming off of a device in a crash. I've talked with a lot of racers that say they felt like the belts wanted to come off but in each and every circumstance, once we got their belts mounted properly, the feeling went away. The racers also said they were more comfortable with the HANS Device and could even pull their belts tighter.
When I first started with HANS, Professor HANS, aka Gary Milgrom, was one of my dependable sources for learning this stuff. No, he is not a "sales hack".
Howard Bennett
The 2" HANS specific harnesses were designed for an issue that is probably not an issue if harnesses are mounted properly. None of these harness manufacturers worked with HANS while I was there for approval. HANS approved the 2" wide shoulder straps because they were either SFI or FIA approved. To my knowledge, HANS still only tests with 3" wide straps.
As Professor HANS mentioned earlier, NASCAR investigated around 4,000 crashes in their division and have never had an issue with the belts coming off the device. Of course, they have much stricter tech inspections. They don't just check for current dates. In the 3 years I did track support, I never found an issue of the belts coming off of a device in a crash. I've talked with a lot of racers that say they felt like the belts wanted to come off but in each and every circumstance, once we got their belts mounted properly, the feeling went away. The racers also said they were more comfortable with the HANS Device and could even pull their belts tighter.
When I first started with HANS, Professor HANS, aka Gary Milgrom, was one of my dependable sources for learning this stuff. No, he is not a "sales hack".
Howard Bennett
10-14-2010 | 04:26 PM
#92
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I don't have videos any more but you can check the CD's that shipped with most devices and it should be on there. I don't know if CD's are still shipping with devices or not. We've had this discussion before when I had a dog in this fight, not anymore. Carry on!
Howard
Howard
10-14-2010 | 04:49 PM
#94
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I don't recall it being a promotional CD. It had the manual, harness mounting instructions, anchor installation instructions, video's from testing and I believe it had a video from NASCAR testing (not too sure about the last one).
Besides, I don't think it is important in the long run since it has passed SFI, NASCAR and FIA testing with no problems.
We can continue this discussion back and forth forever but it really boils down to you building something you can sell to the masses. That is up to you. It is not HANS, Safety Solutions, IST's or Leatt's fault (although HANS seems to be the only recipient of your unhappiness with SFI and FIA). If you are having a problem with SFI and FIA, maybe you should take it up with them.
Howard
Besides, I don't think it is important in the long run since it has passed SFI, NASCAR and FIA testing with no problems.
We can continue this discussion back and forth forever but it really boils down to you building something you can sell to the masses. That is up to you. It is not HANS, Safety Solutions, IST's or Leatt's fault (although HANS seems to be the only recipient of your unhappiness with SFI and FIA). If you are having a problem with SFI and FIA, maybe you should take it up with them.
Howard
10-14-2010 | 05:12 PM
#95
Three Wheelin'
Joined: Nov 2002
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From: Orlando, FL USA
Howard,
So you cannot back up your claim, even though you should have a drawer full of videos. Perhaps the "Professor" could help you out, but he too can't produce any evidence.
What would you call a sales rep who did that?
So you cannot back up your claim, even though you should have a drawer full of videos. Perhaps the "Professor" could help you out, but he too can't produce any evidence.
What would you call a sales rep who did that?
10-14-2010 | 05:20 PM
#96
Three Wheelin'
Joined: Nov 2002
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From: Orlando, FL USA
Here is what can happen if you are not a pro with a $10K seat:
From here.
Video here.
During my "incident" at Watkins Glen in '08, when I took three good hits (one ot the passenger side, a t-bone from another car; one to the rear, when I backed into the wall at 110+; and another hit hit to the passenger side, after the car further rotated and again hit the wall) both of the (3") belts over the HANS I was wearing slid off. Had I a subsequent forward hit, the HANS would have been completely useless...and, in fact, so would have been my shoulder belts, since they were now very loose and off to the side...
Video here.
10-14-2010 | 05:31 PM
#97
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Howard, thank you the reply in post 90.
It seems to echo what has been discussed here several times in the past, the importance of exact geometries when working with a Hans as part of overall safety design. Clearly, his is sometimes a challenge in the "amateur" ranks where there are practical limits to budgets and interior features, seats, varsity, etc.
I do have an additional question. Do you have any history or details behind the "double shoulder belt" harness design that HMS and Penske did a few years back? This was the 3" fir the driver and 2" for the device from Schroth IIRC.
Again, as an engineer, it just seems like H&D have been struggling with an inherent weakness in the Hans system (belt to device interface), and those revisions have been the source of both confusion and discussion.
Thank you for the contributions to the forum
It seems to echo what has been discussed here several times in the past, the importance of exact geometries when working with a Hans as part of overall safety design. Clearly, his is sometimes a challenge in the "amateur" ranks where there are practical limits to budgets and interior features, seats, varsity, etc.
I do have an additional question. Do you have any history or details behind the "double shoulder belt" harness design that HMS and Penske did a few years back? This was the 3" fir the driver and 2" for the device from Schroth IIRC.
Again, as an engineer, it just seems like H&D have been struggling with an inherent weakness in the Hans system (belt to device interface), and those revisions have been the source of both confusion and discussion.
Thank you for the contributions to the forum
10-14-2010 | 06:24 PM
#98
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Howard, thank you the reply in post 90.
It seems to echo what has been discussed here several times in the past, the importance of exact geometries when working with a Hans as part of overall safety design. Clearly, his is sometimes a challenge in the "amateur" ranks where there are practical limits to budgets and interior features, seats, varsity, etc.
I do have an additional question. Do you have any history or details behind the "double shoulder belt" harness design that HMS and Penske did a few years back? This was the 3" fir the driver and 2" for the device from Schroth IIRC.
Again, as an engineer, it just seems like H&D have been struggling with an inherent weakness in the Hans system (belt to device interface), and those revisions have been the source of both confusion and discussion.
Thank you for the contributions to the forum
It seems to echo what has been discussed here several times in the past, the importance of exact geometries when working with a Hans as part of overall safety design. Clearly, his is sometimes a challenge in the "amateur" ranks where there are practical limits to budgets and interior features, seats, varsity, etc.
I do have an additional question. Do you have any history or details behind the "double shoulder belt" harness design that HMS and Penske did a few years back? This was the 3" fir the driver and 2" for the device from Schroth IIRC.
Again, as an engineer, it just seems like H&D have been struggling with an inherent weakness in the Hans system (belt to device interface), and those revisions have been the source of both confusion and discussion.
Thank you for the contributions to the forum
On the double shoulder belts, they have proven to be pretty popular in the Pro classes. As far as I know, they are still available from HMS. There are some special mounting issues that need to be taken into account. That's why I say typically the Pro classes. While I was at HANS, we typically did not recommend them only because we couldn't get racers to mount 5-pt systems properly. HMS or any of their dealers should be able to help. Basically, the 2" HANS straps are mounted on a different bar than the 3" shoulder straps. I've heard that once you try this configuration, you love it.
Howard
10-14-2010 | 07:21 PM
#99
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The weakness I see is the lack of reliable belt retention over the device and the inherent sensitivity to belt geometry.
It is somewhat analogous to trying to lift a weight with a rope pressed between your two palms as opposed to wrapping the rope sound a hand. If you squeeze hard enough the former works, but the latter removes this sensitivity.
I have a very odd perspective on things, it is an occupational hazard. I tend to see only defects and not what is done correctly. Odd way to make a living and go thry life, but it is what it is.
The Hans can clearly be improved to minimize the sensitivity to belt dumping, belt spreading under forward impact, etc but there is little incentive to do so. It is or has become the Microsoft Windows of the H&N restraint world.
It is somewhat analogous to trying to lift a weight with a rope pressed between your two palms as opposed to wrapping the rope sound a hand. If you squeeze hard enough the former works, but the latter removes this sensitivity.
I have a very odd perspective on things, it is an occupational hazard. I tend to see only defects and not what is done correctly. Odd way to make a living and go thry life, but it is what it is.
The Hans can clearly be improved to minimize the sensitivity to belt dumping, belt spreading under forward impact, etc but there is little incentive to do so. It is or has become the Microsoft Windows of the H&N restraint world.
10-14-2010 | 09:03 PM
#102
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P.S.
Howard, please stick around for the Formula 1 threads in this forum. It shows the "lighter side" of the members.
After that, you can move on to oil viscosity and tow vehicle discussions.
Howard, please stick around for the Formula 1 threads in this forum. It shows the "lighter side" of the members.
After that, you can move on to oil viscosity and tow vehicle discussions.
10-14-2010 | 09:55 PM
#103
Drifting
Joined: Sep 2002
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Professor Gary and Howard,
Maybe you can confirm my impressions. I was under the impression that the HANS collar area was the active area with the tethers in that the requirement for function is that the collar area be retained by the belts over the impact pulse. Someone quoted that time to be less than 100ms. The lower yoke tails that some have complained pops out from under the belts, sometimes not during crashes, is not important to HANS function as far as I understand. So if complete exit of the device after the 100ms has occured the device has saved the life. If the lower yoke partly pops out but the upper collar is intact there is no problem.
Some others have commented on the 3" vs. 2" hans specific vs 4 shoulder belt systems pointing to all these systems as a shortcoming to the HANS. At a lecture I was at given by Dr. Melvin many years ago he specifically said HANS recommends 3" belts. He did not believe there was much more to offer from the other designs except to sell more belts.
I happen to be a 4 shoulder belt user in a full containment seat and find the comfort to be better than with 3" or 2" systems. This year my belts expire and I'll buy the same set-up again.
Maybe you can confirm my impressions. I was under the impression that the HANS collar area was the active area with the tethers in that the requirement for function is that the collar area be retained by the belts over the impact pulse. Someone quoted that time to be less than 100ms. The lower yoke tails that some have complained pops out from under the belts, sometimes not during crashes, is not important to HANS function as far as I understand. So if complete exit of the device after the 100ms has occured the device has saved the life. If the lower yoke partly pops out but the upper collar is intact there is no problem.
Some others have commented on the 3" vs. 2" hans specific vs 4 shoulder belt systems pointing to all these systems as a shortcoming to the HANS. At a lecture I was at given by Dr. Melvin many years ago he specifically said HANS recommends 3" belts. He did not believe there was much more to offer from the other designs except to sell more belts.
I happen to be a 4 shoulder belt user in a full containment seat and find the comfort to be better than with 3" or 2" systems. This year my belts expire and I'll buy the same set-up again.
10-14-2010 | 10:06 PM
#104
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Professor Gary and Howard,
Maybe you can confirm my impressions. I was under the impression that the HANS collar area was the active area with the tethers in that the requirement for function is that the collar area be retained by the belts over the impact pulse. Someone quoted that time to be less than 100ms. The lower yoke tails that some have complained pops out from under the belts, sometimes not during crashes, is not important to HANS function as far as I understand. So if complete exit of the device after the 100ms has occured the device has saved the life. If the lower yoke partly pops out but the upper collar is intact there is no problem.
Some others have commented on the 3" vs. 2" hans specific vs 4 shoulder belt systems pointing to all these systems as a shortcoming to the HANS. At a lecture I was at given by Dr. Melvin many years ago he specifically said HANS recommends 3" belts. He did not believe there was much more to offer from the other designs except to sell more belts.
I happen to be a 4 shoulder belt user in a full containment seat and find the comfort to be better than with 3" or 2" systems. This year my belts expire and I'll buy the same set-up again.
Maybe you can confirm my impressions. I was under the impression that the HANS collar area was the active area with the tethers in that the requirement for function is that the collar area be retained by the belts over the impact pulse. Someone quoted that time to be less than 100ms. The lower yoke tails that some have complained pops out from under the belts, sometimes not during crashes, is not important to HANS function as far as I understand. So if complete exit of the device after the 100ms has occured the device has saved the life. If the lower yoke partly pops out but the upper collar is intact there is no problem.
Some others have commented on the 3" vs. 2" hans specific vs 4 shoulder belt systems pointing to all these systems as a shortcoming to the HANS. At a lecture I was at given by Dr. Melvin many years ago he specifically said HANS recommends 3" belts. He did not believe there was much more to offer from the other designs except to sell more belts.
I happen to be a 4 shoulder belt user in a full containment seat and find the comfort to be better than with 3" or 2" systems. This year my belts expire and I'll buy the same set-up again.
As far as Dr. Melvin, he likes the 2" wide belts as most of the stress is along the edges of the strap making 3" straps not as important (I'm not sure that is the correct word). Or I should say the edges carry more of the load than the middle section of the strap.
I assume you are talking about a 4-pt harness system as I do not recall ever seeing 4" wide straps (not that they don't exist?). If a 4-pt system, is it a Y or V shoulder strap, or no sub-strap.
Howard
Last edited by hbennett; 10-14-2010 at 10:39 PM. Reason: Correction
10-15-2010 | 09:31 AM
#105
Mr. Excitement
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Your device was tested per a set protocol as were the others. Many years later there should be some real world data to look at. This data is far less clean as far as graphs and pie charts but it is far more relevant to a human in a track car seat. I am not trying to brush aside the testing I am trying to see if we can add in any newer and perhaps more relevant information.
For the record, Isaac has never run any tests. We contract with labs to run test protocols that were designed by others. The lab technicians then follow the protocols, which incorporate the manufacturers' instructions for all products. In the case of the videos referenced here, the test protocol is per SFI spec 38.1 performed by Delphi Safety Systems and the belts and HANS device were installed per HANS instructions. This is standard lab procedure, otherwise the test is worthless.
You guys are aware of belts coming off and drivers being trapped in burning cars in race settings, right? Especially road racing?
You guys are aware of belts coming off and drivers being trapped in burning cars in race settings, right? Especially road racing?
John H, an ever so slightly faster car changes nothing. I call BS on sound bites, knee jerk thinking and poor fabrication work when I see it. Call me odd but I can smell sound bites.
I would like to see a good true discussion on the merits and physics of various systems without friends and family and old axes coming into play. This is not what color looks best on my new track car or F1 from the recliner. This is more about what can happen when we wreck. I plan to drive and race for a good while and expect to wreck. I am here to learn not prove something.