Insole
An insole ( 2 ) has a heel region ( 8 ), an arch region ( 6 ) and a forefoot region ( 4 ). A pod ( 10 ) comprising an encapsulated liquid is partially embedded in a foam layer in the heel region ( 8 ). The impact of foot strike can lead to large forces on joints in the body. The insole ( 2 ) with the pod ( 10 ) reduces the impact of foot strike and therefore can lessen the impact of steps on the body.
1. An insole comprising:
a heel region, an arch region and a forefoot region;
wherein the heel region comprises a pod and a PU foam layer;
wherein the pod encapsulates a liquid, the pod at least partially embedded in the PU foam layer and partially surrounded by the PU foam on the bottom surface of the insole; and
wherein the PU foam is separated from the pod on the bottom surface by a gap of 0.8 mm to 1.2 mm.
2. The insole of claim 1 , wherein the encapsulated liquid has a viscosity of 18,000 to 24,000 cSt at 40° C. and a density of 0.7 g/cm3 to 1.1 g/cm3.
3. The insole of claim 1 , wherein the PU foam layer has a hardness in the range of 20 Asker C to 40 Asker C.
4. The insole of claim 1 , further comprising a memory foam top layer.
5. The insole of claim 1 , wherein the pod comprises a lip extending around its perimeter, the lip at least partially embedded in the PU foam layer.
6. The insole of claim 1 , wherein the pod is configured to redistribute force associated with a heel strike by displacing the encapsulated liquid.
7. The insole of claim 1 , wherein the pod is elliptical in shape and has a minor axis in the range of 15 mm to 26 mm.
8. The insole of claim 1 , wherein the pod is surrounded by the PU foam layer and a thermoplastic polyurethane shell in a concentric arrangement on the bottom surface of the insole.