Whenever an application has to be moved or activated in a few milliseconds, pyrotechnics are the method of choice. A pyrotechnic charge is initiated by an electrical impulse, generates pressure and pulls or pushes a piston. This movement can initiate a lock or unlock function or can move a load directly.
hirtenberger is the market leader for pyrotechnic actuators for crash-active head restraint systems and for pedestrian safety systems. Other possible fields of application are pyrotechnic switches in steering columns or pyrotechnic actuators for pedal release-, battery disconnection- or roll over bar-systems.
Pedestrian Protection:
Active systems provide space between bonnet and engine if a pedestrian is hit. During the impact of the head, the bonnet is deformed absorbing energy. The generated space grants that the head does not hit hard engine parts.The pyrotechnic actuators deliver the energy to raise the bonnet.
Crash-active headrest-systems:
Active head restraints reduce the distance head to head-restraint in case of a rear side crash. This avoids painful and costly “whiplash” injuries.
Numerous functions may be ingtegrated into the actuator design, such as
- locking in initial position
- retention force over time
- easily resettable after ventilation
- adjustable damping characteristics
- oscillation absorption
Pushing vs. Retracting
hirtenberger produces pushing pyrotechnic actuators with a piston travel from 5 - 130mm in pintype and leadwire versions.
retracting pyrotechnic actuators are mainly used in crash-active headrest systems and adaptive steering columns. The piston with a travel of 5-15mm is retracted within 2-4ms and releases a system (e.g. springs).
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