Dentists chair head rest adjusting mechanism - has triangular linkage and guide members slid by servomotors in backrest

摘要

The adjusting mechanism for the headrest of a dentist's chair, allows it to slide in two planes and tilt in one, at least. It is attached to a support by a hinge or ball joint, and secured to the chair backrest. The support (1), together with a second one (2), forms a triangular linkage with a first hinge and two base hinges, each of the latter being on one of two guide members (6,7) working in the backrest. Servomotors alter the distances (a,b) between the base hinges and the backrest, and the alterations can be for the same or different distances.