While glancing over the L & P Body Print brochure, I noticed they featrue “Soft Touch” springs, that “provide initial softness to the touch, that become firmer as weight is applied”. In other words a progressive spring.
Wouldn’t a progressive spring need be directional? i.e. the softer side of the spring should always be facing up? (If the brochure image is correct, the spring is not symmetrical in shape)
I notice the FlexusComfort and others use the Body Print Spring in their two sided mattresses. If this Body Print spring is in fact progressive, wouldn’t this give a different feel to each side of the bed?
Or perhaps the comfort layers damp the progressive effect to the point it is not noticeable?
[quote]I notice the FlexusComfort and others use the Body Print Spring in their two sided mattresses. If this Body Print spring is in fact progressive, wouldn’t this give a different feel to each side of the bed?
Or perhaps the comfort layers damp the progressive effect to the point it is not noticeable?[/quote]
You certainly have an eye for detail and it’s an interesting question
Innersprings have a very low hysteresis (how much energy they absorb) so the compression forces travel through the spring without being diminished as they go from the top to the bottom of the spring. This means that the softer coils (the ones that either have a wider diameter or more closely spaced turns which have a lower pitch angle) will compress before the firmer coils (that have a steeper pitch angle) regardless of whether they are on the top or bottom of the spring. All coils will become firmer as they compress more deeply so the softer coils will become firmer as they compress more which is when the firmer coils begin to “kick in” and take up the compression forces.
I believe that the picture on the L&P site is probably generic and that the body print is most likely symmetrical but regardless of whether it is symmetrical or asymmetrical it would have the same compression curve no matter which side of the spring was up so a two sided mattress that used it would have the same feel and performance on both sides.
