High grip self locking quick-change angle-poise joins
Application Note 20.
The gravity locked join below employs free rollers shown in red that are placed in a loose assembly between a circular outer rim and an inner shaped three lobe cam block that is also free.
The red rollers are made of sintered tool steel and impregnated with a friction enhancing agent.
Upon gentle rotation the rollers will roll and allow adjustment between the components of the knuckle.
Upon more aggressive movement the rollers lock, trapped by the cam.
As soon as slipping starts the Trib action causes the friction to rise rapidly and the join locks solid.
External levers can be attached to either the outer ring, the rollers or the cam.
Hence the relative positions of these levers can be adjusted by removing the force (usually gravitational) to release the friction grip, usually done by lifting or releasing the force holding the friction faces together.
The following diagrams illustrate the general principle for use with display arms or keyboard arms.
