Patent ID: 8899185

Claim:
A positioning device comprising: a) a base plate with at least one pair of raised portions upstanding from the base plate and one or more valley regions located between the raised portions of each pair of raised portions, wherein the profile of each of the raised portions, and the profile of one or more of the valley regions, is convex; b) a first pair of raised portions, a second pair of raised portions and one or more valley regions located between the raised portions in at least one of the first and/or second pair of raised portions, wherein the profile of each of the raised portions and the profile of one or more of the valley regions is convex; and c) wherein the base plate comprises forward and rearward facing ends and wherein the raised portions comprise a pair of elongated and parallel raised portions which form two raised ridges that run towards the forward facing end in one direction and towards the rearward facing end in the other direction, wherein a valley is located between the two raised ridges and further wherein the profile of each of the two raised ridges and the profile of the valley located between the two raised portions is a convex arc running in the direction between the forward facing and rearward facing end portions.