If you often drive or ride in a car, have you ever questioned the necessity of the seat headrest? It's not soft enough and doesn't fit the neck well enough. Why can't car companies design it to be more comfortable?
In fact, the seat headrests on vehicles were not originally created for the comfort of the occupants. Their real purpose is to protect the cervical vertebrae of the occupants.
In today's "Collision and Insight", we will review the "Growth History of Car Headrests" and see how cars use headrests to add points to their own safety.
Text?|?Yu Yan
Pictures?|?Hongyi
01? "Expensive" is a car, but the one used is a carriage chair
In 1886, Germany produced the world's first car that was patented as an "automobile". The inventor Carl Benz called it "Mercedes-Benz No. 1." The reason why it was patented is that unlike previous tricycles that were pulled by animal power, it was driven by a gasoline engine. At this point, the century-old development history of automobiles has begun.
Mercedes-Benz One was born out of a carriage, so its seat still looks like a carriage seat: a leather cushion placed on a wooden board is the seat; the backrest is short and can only protect the waist; two people The seats are connected together without separation; as for the headrests, of course there is no shadow yet.
At the beginning of the 19th century, many well-known automobile brands were born in European and American countries, production lines also developed maturely, and automobiles became mass-produced commodities and entered thousands of households.
With more people driving, traffic accidents have also increased significantly. In order to reduce the casualty rate in traffic accidents, the government continues to urge car companies to improve their cars, such as changing the front seats of the cars from "two-seat through-type" to "one-seat-one-seat". At the same time, the seat padding is softer and more elastic, and it also increases The height of both sides of the seat cushion and the backrest has been increased to wrap the occupants.
But until the mid-20th century, car seats still did not have headrests.
02? The terrible "whiplash injury" can only be cured by a "headrest"
After counting traffic accidents, people at that time found that one of the common injured parts of the passengers was the cervical spine - —Small in size, strong in flexibility, and connected to the head with a relatively large weight and volume. Once it is impacted by an external force, the spinal cord wrapped in the cervical vertebrae is easily stretched and squeezed and injured.
When a vehicle impacts, since the inertia of the human cervical spine and head lags behind the body, the body will first follow the direction of the car, and then the neck and head will be pulled by the body, bending first and then rebounding. The neck is pulled violently and quickly, like a whip, making it extremely vulnerable to injury. Medically, it is called "whiplash."
Image source: China Insurance Auto Safety Index
How serious are the consequences? According to statistics, more than 1/4 of rear-end collisions involve "whiplash" injuries to the occupants. Because most occupants will subconsciously brake suddenly during a rear-end collision, and all the deceleration force will act on the fragile neck. Even if the speed is only 10km per hour, the force is very huge. In severe cases, the occupant may even be paralyzed or killed due to a broken neck.
As a result, automotive engineers thought of adding a head restraint to the seat to limit the backward tilt of the head relative to the body and reduce the damage to the occupant's cervical spine.
This restraint accessory we call a "headrest" is finally making its way into history.
In 1969, the United States took the lead in enacting mandatory regulations requiring automobile companies to equip new cars with head restraints to ensure the safety of passengers. At this time, automobiles have been developed for more than 80 years.
The headrest appeared late, but it still saved many people’s necks. Data show that occupants who use head restraints correctly are 40% less likely to experience neck pain than those who use incorrect headrests. The probability of whiplash injuries when using high-quality headrests is 24% lower than when using inferior headrests.
03? To make full use of the safety of the headrest, you need to use it correctly
Nowadays, car headrests are basically designed with a concave upper half and a convex lower half, and the overall It protrudes beyond the backrest, which makes the back of our heads always pressed against the headrest, making it uncomfortable.
But this design is to make the headrest and seat more in line with our physiological curves and better absorb impact forces.
In reality, many people put neck pillows on their seats in order to make their necks more comfortable when riding in a car. This practice actually destroys the overall safety mechanism of the car seat.
When an accident occurs, the head will rebound and tilt back, and the neck pillow will block the neck during the rebound process. When the head rebounds to the headrest, the cervical vertebrae will still stop on the neck pillow. , easy to bend excessively, causing injury.
On the contrary, if there is no neck pillow, the head and neck will rebound at the same time, and then the head pillow will bear the head impact force. At the same time, the back will also lean on the backrest, and the head and neck will , the back basically maintains the physiological curve throughout the process, and the probability of injury is reduced.
Nowadays, the seat restraint system composed of headrest, seat cushion and backrest is working together with seat belts and airbags to fix the position of the occupants.
China Insurance Auto Safety Index has evaluated the headrest/seat protection effect of 52 cars in the past three years. The results show that 49 models have received excellent (G) evaluations, and another 3 models received an A (good) rating, indicating that current car headrests/seats are generally very protective.
(Send "headrest" to the public account "Eddy Automobile Network" to view the evaluation results of 52 models)
The inconspicuous headrest actually plays a role in collision accidents The protective effect cannot be ignored. Its birth and development process is the epitome of the development of automobile industry design from simple and rough to sophisticated and meticulous.
For more car safety knowledge, please continue to pay attention to Eddie Auto's column "Collision and Insight".
This article comes from the author of Autohome Chejiahao and does not represent the views and positions of Autohome.