Patent ID: 6962542

Claim:
A pulley comprising: a set of discs adapted to be fitted on a shaft of a transmission, at least one disc being axially displaceable and provided with cylinder/piston means, said cylinder/piston means comprising at least one pressure chamber with radial walls and concentric cylinder walls, at least one of said radial walls secured to one of said concentric cylinder walls by an immovable fit i) radially either to a sleeve part of a disc or to a part of said shaft and ii) axially to a shoulder part of said sleeve part or of said shaft, said at least one radial wall comprising, near said fit, a resilient hinge connecting to a lower portion of a radially extending wall part, the radially extending wall part having outer and inner axial wall faces extending uninterruptedly smoothly up to a radially inner diameter, wherein the resilient hinge comprises i) a foot part, axially protruding relative to the lower portion and integral therewith, and ii) a transition section providing a smooth curve between the inner axial wall face of the radially extending wall part and the axially extending foot part, wherein, the foot part at the radial inner, and axially outer side is provided with a recess, of which the radial extension starts at a location axially outwardly beyond the transition as seen from the axial wall face towards the other axial wall face.