Patent ID: 8794396

Claim:
A caliper comprising: a) a piston bore having a piston bore axis and a piston bore surface; b) a piston in the piston bore; c) an inboard brake pad and an outboard brake pad; and d) a seal groove, having a seal, located in the piston bore proximate to an open end of the piston bore, the seal groove comprising: i) a bottom wall; ii) a front wall extending between the piston bore surface and the bottom wall; iii) a rear wall extending between the piston bore surface and the bottom wall at an angle of about 5 degrees or greater and about 60 degrees or less with a line perpendicular to the piston bore axis; iv) a projection in a central region of the bottom wall suitable for allowing twisting of the seal during a brake release, wherein the projection is generally arcuate and convex in shape; v) a forward recessed region in the bottom wall on a side of the projection located proximate to the front wall, wherein the front wall and the bottom wall connect in the forward recessed region; and vi) a rearward recessed region in the bottom wall on a side of the projection located proximate to the rear wall, wherein the rear wall and the bottom wall connect in the rearward recessed region; wherein the bottom wall spans between and connects the front wall to the rear wall; wherein the rear wall, beginning proximate to the bottom wall, continuously diverges away from the front wall as the rear wall extends away from the bottom wall and towards the piston bore surface; wherein the seal, in a neutral position, has a front side that extends away from the piston bore axis and into the forward recessed region and a rear side that extends down and into the rearward recessed region and a gap exists between the rear side of the seal and the rearward recessed region; wherein the seal, during a brake apply, is rotated about the projection so that the front side of the seal is rotated into contact with the bottom wall and front wall in the forward recessed region and the rear side is rotated away from the rear wall; and wherein the seal, during a brake retract, is rotated about the projection so that the front side of the seal is rotated away from the front wall and out of contact with the bottom wall and the rear side is rotated towards the rear wall and further into the rearward recessed region when compared to the neutral position and during a brake apply so that the gap between the rear side of the seal and the rearward recessed region still exists but is reduced in size.