Patent ID: 7273201

Claim:
A tiltable mounting for a payload comprising, a platform to receive the payload, a support, means to mount the platform for tilting movement on the support about a horizontal axis to either side of a neutral position in which the platform is disposed above the horizontal axis and spring actuated counterbalancing means to control tilting of the platform/payload to balance the platform throughout its range of movement to either side of the said neutral position, wherein said spring actuated counterbalancing means comprises a cam which rotates with the platform, a cam follower engaging the cam and located on a pivotally mounted lever, linearly acting spring means to convert rotation of the lever into linear input to the spring means whereby a spring force generated in the spring means resist rotation of the cam and thereby tilting of the platform, the shaping of the cam being such that the spring means is displaced linearly in accordance with a function of sine θ/2 where θ is the absolute angle of tilt of the platform from the neutral position (in which θ is 0) so that the spring force generated in response to tilting of the platform counterbalances the platform/payload throughout a prescribed range of movement to either side of said neutral position.