Car Seat Testing
The Gorman Pelvic Support Seat has been designed with safety in an accident always in mind and the strength of the seat and various components is of obvious importance. Good engineering practice and expertise have been used at all points in the design with over specification of steel thickness, dimensions etc, rather than detailed calculation to minimise component cost.
However as any engineer knows there is no substitute for sensible destructive testing to prove that the design is indeed safe.


Testing of Seat Back

The force in an accident on the top of the back of the seat produces a very large force at the hinge points of the back rake. In order to estimate the strength required a normal seat was taken and tested to destruction as shown.


The same test was then given to the Gorman Pelvic Support Seat to the level when components were damaged. In the Gorman Pelvic Support Seat it turned out to be the front cross shaft which was permanently bent by this force. This was considered to be a good and safe form of failure as even with gross distortion of this component there was no sudden failure only a progressive bending.

This will absorb energy in the event of an accident (in a rear end collision obviously the force will initially be of the body backwards against the seat back, in a front end collision the impact of the body rebounding from the seat belts is however also very large. In both of these cases the progressive distortion of the position of the seat back would seem likely to reduce the likelihood of injury. Also the distorted component is very easy to replace during accident repair being only bolted into the position by four screws at the front of the seat and will be replaced free of charge if returned to Gorman Design Ltd.


Head Rest Testing

The head rest on the Gorman Pelvic Support Seat consists of an outer steel frame with firm foam padding and a net centre. The reasons for this form of construction are expanded under Design Philosophy. Without any specification for the strength of such net, experiment was the only way of ensuring safety. The strength of standard head rests was assumed by checking the size and grade of steel tubes used and a steel frame of similar strength was then constructed. Various forms of nylon and polypropylene netting were then tried to find one that was easy to see through, elegant in form and which could not be broken before the steel frame was totally distorted.

 It was then necessary to choose a strength of steel for the frame of the head rest to be used with the production seats.
After various experiments it was decided to use a steel bar of similar bending strength to the steel tube as it would distort more progressively without buckling or folding in an accident