Head & Neck Restraint Systems - Tech, Statistics - Circle Track Magazine

Head And Neck Restraints

If you’ve followed racing for the past two years, then you know what a head-and-neck restraint system is. You know why it exists and what it does to help prevent injuries to the brain.

Knowing all that, and assuming you drive a race car, own one or help make it go fast, why don’t you have one of these systems or make sure your driver has one on?

A head-and-neck restraint system is just as much a part of your racing effort as tires, wheels and an engine, or at least it should be. It’s all there, in black and white. Test data garnered from crash tests using instrumental dummies tell an interesting story. Boiled down, that story is either wear one or die.

That might seem a bit dramatic, but it’s the truth. The majority of head-and-neck injuries in racing are caused by the neck trying to do its job and failing against the massive force exerted on drivers by impacts with walls or other cars.

Following the death of Dale Earnhardt at Daytona in 2001, there was a massive investigation into the circumstances of the crash. In the course of that investigation, the investigators determined that the change in velocity—otherwise known as the Delta V—generated in that fatal crash was 42 mph. Delta V is not about how fast you’re going on the track. It’s about how fast you hit the wall and how fast you come off it.

If Earnhardt’s Delta V was 42 mph, then how difficult is it to imagine that the Street Stock or Late Model you drive can generate that kind of force? If you’re traveling 50 or 60 mph, hit a parked car or something and stop, that’s more than enough force to generate a head or neck injury. You don’t have to be racing at Daytona or Talladega to generate this kind of impact.

Trevor Ashline, whose résumé lists Swedish restraint-system manufacturer Autoliv in addition to BSR, is the inventor of the Hutchens Device. It is one of two devices mandated by NASCAR and other sanctioning bodies for its drivers. His advice to racers of all stripes, budgets and abilities is: wear it.

“There’s no reason not to, especially a harness device like this one,” he says. “There are no negatives.”

How much are you worth? For the cost of a quality racing suit, you can outfit yourself with something that will give you a chance to survive a heavy impact. The Hutchens Device in its current form costs $300-$325, depending on the bottom-end hardware for the buckle system. Ashline recently debuted an alternate version of the original, and its cost is $400. The difference in the two is that the new unit does not buckle into your safety harness. It uses your body’s own structure to keep your head in place and out of lethal range.

“Once you put it on, you can hook the helmet to it outside the car,” Ashline says. “When you get in the car, you just pull it snug. When you sit down, the points change. You’re using body kinematics (motion) to tighten the belts up. This one (the new unit) has a rebound strap on it, where it will try to catch your head going back. I’ve equaled the best numbers I’ve ever gotten on the original Hutchens. The original hooks to the belts as its anchor; the new one uses your pelvis as its anchor.”

What you’ll get upon purchasing either one is: the harness, leg straps, two upper tethers and the hooks for the helmet, along with the screws for the helmet.

The HANS Device ranges in price from $1,275 to $2,000, depending on the type of racing you do.

Neck Collars

OK, the price tag is a little steep for some of the more budget-conscious racers out there. Why not just pass on the Hutchens and go with a neck collar?

“Neck collars don’t do it,” Ashline states. “The people who thought that worked believed that the head just rotates down, and it doesn’t in a crash. The head first translates forward. Your upper torso belts hold you back, and your head goes straight forward until your neck tries to pull it down. You get full extension, you load the belts all the way and you’re (neck is) out here like this (three or four inches), then your neck starts to pull you down and it misses the collar altogether. You’ll never hit the collar.

“Does the collar work with a Hutchens device?” Ashline continues. “Yes, because you have the collar in close to your neck. The Hutchens Device is limiting the stretch of your neck, and it’s going to force your head down. That will help you because the rotation of your head as it is pulled down gets you into the collar. I don’t disagree with using a neck collar with a Hutchens Device. If you do not use a Hutchens or a HANS, you’re playing with fire. Your neck can’t hold the forces of the weight of your head, trying to take it off the top of your shoulders.”

Load Limiting

The Hutchens Device and the higher-dollar HANS both act on the same principle: They limit the loading on the weakest joint in the human body in terms of impact. Your neck is very strong when it’s holding your head up under normal gravity. When impact forces of 800 to 1,500 pounds (1 Newton = 0.2248 pound of force) are at play, it’s a weak collection of bones held together with discs and ligaments. Don’t be misled by the fact your Street Stock only reaches 80 mph. Forces generated from an impact at that speed can kill you just as dead as impacts at 160 mph.

“Load limiting is the key,” Ashline says. “Restrain the occupant early, limit the load the occupant sees and then ride them out. That’s the key. You don’t want them to spike. The spike comes when you restrain late and everything hits quickly. If you restrain early, you can take that force out, and if you use some kind of load-limiting device, like the Hutchens Device ... it comes in early. Because it does, you never really get the high (load) numbers. It brings you up, over and down, and that’s what you want to see.”

The first thing you want to do is to have your pelvis locked down in the seat.

“In the first 20 milliseconds, you’ll start loading up the belts as the occupant moves forward,” Ashline explains. “As that forward movement starts, the occupant tightens the belts. The biggest thing you want to do in any type of crash is to lock down the pelvis and reduce the amount of movement there early. Then it’s easier to control the chest and the head. Center of mass is your pelvis, and it can handle a lot more g-forces than the rest of you can. When you lock the pelvis down, you have this load on your lap belt that’s 2,500-3,000 pounds. That provides a really good anchor for the (original) Hutchens device.”

He continues, “The straps that go up the back are very heavy material with low elongation. As your head starts to go straight forward, it tightens up the straps. The upper torso starts moving because your pelvis is locked in and rotates into the upper belts. It limits the amount of movement your head is going to see. The device comes into the lap belt, and the lap belt is under so much load there is no way the harness is going to move it. The helmet straps limit the whipping motion of the head.”

Lab Tested

Ashline, as an engineer, recommends that whatever you decide you need for a head-and-neck restraint, make sure the product has been tested under laboratory conditions.

“You learn how to watch the kinematics, learn where the loads are going,” in a laboratory/crash sled setting, he explains. “The only way you get to do that is to run your own sled tests. The (safety) guys who are out there who aren’t doing sled testing have no idea what they’re doing. You can sit there all day long and say, ‘my thing is the best in the world.’ You put that on a sled test and that will tell you. That’s the only way you can do it, in a laboratory setting where you can study the motion and see how your system interacts with the rest of the systems in the cockpit. If you’re not doing that, don’t go there, don’t buy it, don’t even think it’s going to be right.”

As for the HANS, developed by sports-car racer Jim Downing, it does its job well, according to Ashline. “The end result stays the same, and that’s good,” Ashline says. “The HANS is a good product, it works well. I’ve done a lot of testing on it. They are just going a different way than I am.”

While this article is focused on head-and-neck restraints, there’s more to this than just going out to buy a Hutchens Device or a HANS Device. All systems in the cockpit—belts, restraints, steering column, seat, padding, etc.—work together, and if they are working in concert, the result is a better opportunity to survive a crash.

Seat Belts and Head Padding

One piece of advice Ashline gave that applies across the scope of racing is on seat-belts. “The seatbelt and the seat are the number-one things you can do to be safe,” he says. “Mount your belts correctly. If you can get good geometry on your seatbelts, you are so far down the road into a good restraint system it’s not funny.” Seatbelt manufacturers supply mounting instructions—use them.

Padding around your seat’s head restraints is important too. Ashline’s advice is to go with thicker, more impact-absorbing padding there. “Formula One, the IRL and CART require three inches of energy absorption padding around their headrests,” Ashline says. “It doesn’t give you a big spring-back. You want something that rides you down and is strain-rate dependent—which means that the faster you ride into it, the more energy it will absorb. We’re working with urethane foam right now, which is harder than other types of foams and gels. The visco-elastic foams and gels are temperature-dependent, so when it gets cold or hot, they do too. The gels are heavy, too. You need a minimum of three inches.”

The idea for this story is to get you, the racer, to think in terms of safety in ways that are outside the old standby. If you drive a racing car, whether it be a full-on Late Model or a Hobby Stock, you need one of these devices, just like you need a helmet, firesuit and gloves. It is not a question of whether you can afford one. The question is rather, can you afford not to have one?