Swivel unit having split ball

Claim 1

A SWIVEL UNIT OF THE CLASS DESCRIBED COMPRISING A HOLLOW SHELL, A FIRST MEANS MOUNTED TO SAID SHELL FOR PIVOTAL MOVEMENT ABOUT A FIRST AXIS, SAID FIRST MEANS INCLUDING A SPHERICAL PORTION DISPOSED WITHIN SAID SHELL AND A NIPPLE EXTENDING THROUGH AN ELONGATED SLOT IN SAID SHELL, BIASING MEANS URGING SAID SPHERICAL PORTION INTO ENGAGEMENT WITH A SPHERICALLY SHAPED INTERNAL SURFACE OF SAID SHELL; SAID SPHERICAL PORTION INCLUDING A FIRST AND A SECOND SPHERICAL SEGMENT AND A DISK SANDWICHED BETWEEN FLAT SURFACES OF SAID SEGMENTS; SAID NIPPLE SECURED TO SAID DISK AND EXTENDING THROUGH AN APERTURE IN SAID FIRST SEGMENT POSITIONED IN ALIGNMENT WITH SAID SLOT; SAID DISK BEING MOUNTED FOR ROTATION ABOUT A SECOND AXIS DISPOSED AT RIGHT ANGLES TO SAID FIRST AXIS; A PROJECTION AND ANNULAR GROOVE MEANS FOR LIMITING SAID ROTATION; SAID PROJECTION AND ANNULAR GROOVE MEANS BEING CARRIED BY SAID DISK AND ONE OF SAID SEGMENTS; A WASHER INTERPOSED BETWEEN SAID BIASING MEANS AND SAID SECOND SEGMENT; MEANS FOR MAINTAINING SAID WASHER AGAINST ROTATION WITH RESPECT TO SAID SHELL; SAID WASHER HAVING A SPHERICAL SURFACE BEARING AGAINST THE SPHERICAL SURFACE OF SAID SECOND SEGMENT; KEY MEANS PROJECTING FROM THE SPHERICAL SURFACE OF THE WASHER AND ENTERED INTO GROOVE MEANS IN THE SPHERICAL SURFACE OF THE SECOND SEGMENT TO MAINTAIN THE SECOND SEGMENT AGAINST ROTATION ABOUT SAID SECOND AXIS YET PERMIT PIVOTING ABOUT SAID FIRST AXIS.