Laterally adjustable armrest for a chair

Claim 1

A mechanism for adjusting the height of an armrest (1) relative to the seat of a chair comprising: a first elongated hollow tubular member (21) adapted to be secured to the frame of the chair; a second elongated tubular member (23) engagable interiorly of said first tubular member (21) and capable of mounting the armrest (1) of the chair at one axial end thereof; means defining a plurality of axially spaced sockets (24) on the outer periphery of said second tubular member (23); means for selectively moving the tubular members (21, 23) relative to one another to adjust the position of the armrest (1) and for selectively locking the tubular members (21, 23) in a pre-selected position relative to one another, said means comprising; a collar (20) circumscribing said first tubular member (21) and spaced therefrom to define a chamber C for a spring biasing means (28); a circumferentially extending ring insert (29) mounted in the lower end of the chamber C and having on its internal peripheral surface a circumferentially extending groove (25); a cavity defining seat (22a) in the side wall of the first tubular member (21) for a ball (22) selectively engagable in one of the sockets (24) in said second tubular member; means preventing relative rotation of the tubular members (21, 23) relative to one another whereby axial movement of the collar (20) against the bias of the spring (28) in one axial direction, positions the groove (25) in the ring insert (24) in alignment with the ball (22) permitting relative longitudal movement of said first and second tubular members (21, 23) so that when the ball (22) aligns with another socket (24) and the collar (20) is released, the tubular members (21, 23) are locked in a new position relative to one another.