• The mechanical solutions are, first, a device between the seat cushion and the backrest that enables the backrest to move backwards throughout the operational sequence and, secondly, a wire frame suspended in a set of additional springs in the backrest which helps prevent the occupant from being pressed too far back and thereby being subjected to the catapult effect.
• During the first stage, after the impact, the body is thrown backwards and then cushioned in a controlled manner with the whole of the spine safely against the backrest. In order to reduce the force, the backrest is allowed to move backwards with the occupant. This backward movement prevents the body being thrown forward. The upper part of the backrest moves upwards and forwards, thereby providing extra support and protection for the neck and the head.
• This is the first stage of the WHIPS function and is called the parallel phase.
• During the second stage, the WHIPS mechanism allows the backrest to tilt backwards, up to 15 degrees, thereby absorbing impact energy, reducing the movement of the body and heavily reducing the risk of the catapult effect which causes the whiplash injury.
• Tests conducted by Volvo during the development of the system reveal that the WHIPS system can reduce the acceleration forces in the neck by approximately 50 percent.
• Rear seat passengers are not affected by the movements of the WHIPS front seats in an impact situation. They move in the same way as the occupants of the front seats, making the entire movement parallel, without any negative interaction such as the legs being trapped and injured between the front and rear seats.
• The WHIPS system is activated at lower speeds which means it must be easy to repair and it is. The mechanical parts that are affected are simple and inexpensive and, in most cases, they can be replaced without needing to replace the entire seat.
• Passenger protection in side impacts is perhaps the most difficult area in terms of safety development, because of the lack of space or the minimal distance involved only 25-30 cm (10 - 12 in). Passengers sit very close to the point of impact. This must therefore be compensated for in one way or another.
• The SIPS structure has been extensively upgraded and its interacting components consist of the energy-absorbing elements in bottom rails, pillars, cross-members, roof and seats, plus energy-absorbing materials in the doors.
• This has been supplemented with more, further improved padding in all the roof pillars and along the edges of the roof lining. This material has a hard feeling when it is touched, but it yields in a "controlled" manner and absorbs energy when it is hit in an impact.
• The second step in the continued development of the SIPS system was the introduction of the SIPS bags in 1994- now a standard item on all Volvo cars.
• The Volvo side airbag is located in the outer part of the backrest and is therefore always in the optimum protective position in relation to the occupant.
• SIPS further reduces the risk of severe chest and pelvic injuries as its function is to keep the occupant away from the side of the car.
• In the Volvo S80, the side air bags are trigged by electronic sensors, one in the B pillar and one behind the rear door. Their position makes the reaction time from moment of impact to triggering the bag very short. A factor which is of vital importance in side impacts.
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