Buckle up for seatbelt history
Seatbelts are a standard safety device these days, but it took a while for the motoring world to widely accept their lifesaving value.
Engineer and aviation enthusiast George Cayley is considered to be the inventor of the seatbelt.
As a pioneer of flight in the 1800s, Englishman Cayley developed the lap belt to stop pilots falling from their gliders.
Safety second
Early motoring seatbelts were also the lap type, similar to those found in planes today. In 1949, the Nash Motor Company in Wisconsin, USA, was the first carmaker to offer seatbelts in its vehicles.
But some motorists questioned the value of this new-fangled device, claiming it could cause internal injuries, prevent an effective escape from a car submerged in water, and was simply uncomfortable.
Although seatbelts became increasingly available as an optional extra, motorists often declined to have them installed, and some car owners even removed belts that had already been fitted.
But research continued to show the safety benefits of seatbelts, and over time, more carmakers fitted them to their vehicles.
From 1 January 1969, it became mandatory for all new passenger cars in Australia to be fitted with front seatbelts, while rear seatbelts became compulsory in January 1971.
In 1970, Victoria was the first jurisdiction in the world to legislate that seatbelts must be worn if fitted to the vehicle.
Belt breakthrough
Although lap belts provided some restraint, they offered little control over torso and head movement.
Volvo engineer Nils Bohlin made a design breakthrough in 1959, developing the three-point seatbelt. Clicked into place at a fixed point near the hip, this style of belt is seen in nearly all modern passenger cars.
Volvo’s PV544 model was the first car to feature this new design, which not only spread the stress of impact more broadly across the body, but was operated with just one hand, unlike the lap variety that busied two hands.
In an inspirational act of philanthropy, safety champion Volvo made its seatbelt patent free for use by other carmakers, which is credited for saving countless lives.
While the three-point belt was a significant development, it still needed to be adjusted manually. This was often done incorrectly, leaving too much slack and reducing its effectiveness.
The arrival in the 1960s of the inertia-reel design with retractable belt was a major game changer, which is still in use today – albeit with the odd refinement over the years.
The spring-loaded ‘retractable’ feature allows the belt to recoil into its holder until it fits the user comfortably. The ‘inertia’ component locks the seatbelt during a crash, preventing the user from being launched through the windscreen.
Although heroically effective, this style of belt allows drivers to lean forward from the seat while the car’s moving, which reduces the time for safety features like airbags to effectively deploy in a collision.
Taking up the slack
In the early 1980s, Mercedes-Benz developed the pretensioner. When crash-detection sensors are triggered, an explosive similar to those used in airbags pushes a piston that winds in slack and holds the user firmly in position. Pretensioners also come in mechanical and electrical styles.
Many modern seatbelts use a load limiter in concert with a pretensioner. In a major crash, the pretensioner reels in belt slack, but once a predetermined impact force is reached, the load limiter allows some belt release, to lessen chest, neck and shoulder damage. All this happens in milliseconds, together with the deployment of the vehicle’s airbags.
Mercedes-Benz also came up with a pre-pretensioner, marketed as PRE-SAFE which uses sensors to detect when a crash is likely to happen, and adjusts the seat and seatbelts accordingly.
Tweaks
In 2009, Ford invented the inflatable seatbelt for rear-seat passengers, who weren’t benefiting from airbag, pretensioner and load limiter tech as much as folk in the front.
Basically an airbag in a seatbelt, these were available in some Fords, Mercedes and Lexus vehicles, but have since been discontinued in favour of other forms of airbag and seatbelt developments.
German automotive technology company ZF have come up with heated seatbelts for EVs, to reduce the amount of battery power needed to heat the whole cabin on wintry days. This offers no extra protection for vehicle occupants, but improves the range of the car and keeps the torso toasty on those chilly Hamburg mornings.
Seatbelt tech has come a long way since George Cayley designed a device to stop his airborne buddies toppling from their gliders.
While there have been substantial developments in vehicle safety over the years, the three-point seatbelt remains one of the most important, dedicated safety features in a car.