Patent ID: 7434880

Claim:
A mobile joint ( 1 ) suitable for a sitting device, comprising a first and second joint element ( 10 , 20 ), which are pivotally connected by a shaft ( 30 ), to allow tilting forwards and backwards of the sitting device caused by the displacement of the users weight, wherein the mobile joint comprises a first and second parallel plate spring ( 18 , 19 ) with first and second ends, with an intermediate blocking element ( 11 ), wherein each plate spring ( 18 , 19 ) in the first end is connected to the first joint element ( 10 ), and in the second end is glidingly abutting the second joint element ( 20 ), the second joint element ( 20 ) is allowed to tilt forwards until the first plate spring ( 18 ) abuts the blocking element ( 11 ), the second joint element ( 20 ) is allowed to tilt backwards until the second plate spring ( 19 ) abuts the blocking element ( 11 ), the first and second plate spring ( 18 , 19 ) each having an axis of rotation that is displaced in relation to each other and the shaft ( 30 ).