Patent ID: 7090458

Claim:
A mechanism comprising: a base; a platform that is movable relative to the base in a plane extending through the base and the platform; the base being provided with two rotatable drive members connected to the platform via a pair of linkages, each linkage including a drive link having a first end fixed for rotation with a respective drive member and a driven link having a first end pivotally connected to the platform, and respective second ends of the drive and driven links being pivotally connected together, one of said linkages further including means for locating the platform relative to the base and for maintaining the platform in a predetermined orientation with respect to the base during movement thereof, wherein the means for locating includes a bell crank provided at a pivotal connection between the drive and driven links, a first location link pivotally connected between one arm of the bell crank and the base, and a second location link pivotally connected between the other arm of the bell crank and the platform.