Mercedes-Benz wedge-pin door lock
wedge-pin door lock
Stuttgart, Jul 02, 2003 At the instigation of the then managing director of Daimler-Benz, Dr. Ing. Wilhelm Haspel, research into accident safety was introduced as a new development field in 1939. The head of the newly created unit was Karl Wilfert, an engineer who was as progressive as he was unconventional. His “experimenter”, working independently along the lines of extremely futuristic thought patterns, was the ingenious Béla Barényi, who was to become famous as the doyen of passive safety in later years. The cooperation of these two men laid the foundations of decades of ever more detailed and ever more scrupulous safety design for Mercedes-Benz passenger cars.
Even in these early stages, the investigation and evaluation of cars damaged in accidents provided pointers and ideas for the design of models and prototypes of “safety vehicles”.
One of the more conspicuous criteria in accidents were doors which flew open even in relatively harmless crashes. Since doors were still hinged at the rear in those days, this often had serious consequences when the driver or passengers were catapulted out of the car. Some 25 percent of road accident fatalities were attributable to doors bursting open.
Since retaining straps were still largely unknown, not to mention seat belts, the task was to prevent the doors – and especially the front doors – from bursting open. The engineers focused on the door locks most of which featured merely the classic catch even though car doors were already fitted with double retaining wedges “for safety’s sake”, i.e. to prevent them from inadvertently opening on a bumpy road.
As early as 1949, numerous experiments led to the first patent, entitled “Locking mechanism, especially for motor vehicles” and registered by the German Patent Office under No. 827 905 for Daimler-Benz AG on April 23, 1949.
These first safety locks did prove themselves but their design wasn’t the final pearl of wisdom: under certain circumstances, for instance in rollovers, doors still tended to burst open even with these newly designed locks. The deficits were made out in the interplay of several elements, calling among other things for the fundamental improvement of passenger cell rigidity which declined significantly as soon as the doors opened.
So the engineers continued their search for a lock version that was to keep the doors closed under all circumstances in order to retain and secure the valuable survival space for the occupants.
And after having gone through several preliminary stages, they finally came up with a famous, pioneering design: the Mercedes-Benz wedge-pin door lock with two safety detents. The patent – DBP No. 1 089 664 – for the “Pin lock, especially for motor vehicles” was granted on July 2, 1958.
The wedge-pin door lock was incorporated in large-scale production for the first time in the Mercedes-Benz 220 of 1959, known as the “tail-fin” and the world’s first car with holistically designed safety bodywork, that is with a rigid passenger cell, crumple zones front and rear and an interior in which all appointments were recessed, rounded or padded so as to reduce the injury hazard in an accident.
The passive safety criteria, developed by Mercedes-Benz in years of research and testing, namely
Extremely rigid passenger cell
Crumple zones front and rear
Lateral impact protection
Safety door locks
Split steering column
Safety steering wheel
Seat belts
Easy-to-repair front and rear sections
were for the first time incorporated in the 1959 sedan. The latest development stage has meanwhile been reached with the innovative, anticipatory PRE-SAFE safety system from Mercedes-Benz. With PRE-SAFE, the delineation between passive and active safety is overcome for the first time – representing another major step towards the target of accident-free motoring. Mercedes-Benz
Bocklenberg & Motte wedge-pin door locks in the W163
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