A linkage system is disclosed that is suitable for connecting an input shaft and an output shaft. The linkage system has a wide variety of applications, with non-limiting examples disclosed including a hinge for a door or gate, and a hub for a bicycle or similar. The linkage system comprises a first member having an input location fixedly connected to the input shaft, a second member having an input location pivotally connected to an output location of the first member, a third member having an input location pivotally connected to an output location of the second member, and a fourth member having an input location pivotally connected to an output location of the third member and having an output location fixedly connected to the output shaft. The linkage system has an engaged mode of operation whereby rotation of the input shaft causes corresponding rotation of the output shaft, and a disengaged mode of operation whereby the input shaft can be rotated independently of the output shaft.