Angularly adjustable seat

Claim 1

A SEAT HAVING A TILTING BACK, RESILIENT MEANS URGING THE BACK TO FOLD IN THE DIRECTION OF THE SEAT, AND MEANS FOR LOCKING THE BACK IN A VERTICALLY SWUNG ADJUSTED POSITION RELATIVE TO THE SEAT, SAID MEANS COMPRISING TWO TUBULAR ELEMENTS SLIDING ONE WITHIN THE OTHER AND MECHANICALLY CONNECTED BY THEIR FREE ENDS THE ONE TO THE SEAT THE OTHER TO THE BACK, THE INNER TUBULAR ELEMENT TERMINATING INSIDE THE OUTER TUBULAR ELEMENT IN SPACED ARMS HAVING A SCORED OUTER SURFACE FOR CLAMPINGLY ENGAGING THE INSIDE OF THE OUTER TUBULAR ELEMENT, SAID ARMS HAVING A RESILIENCY THAT TENDS TO KEEP THEM OUT OF LOCKING ENGAGEMENT WITH THE INNER SURFACE OF THE WALLS OF THE OUTER TUBULAR ELEMENT, WEDGE MEANS MOVABLE INTO AND OUT OF THE END OF SAID INNER TUBULAR ELEMENT, AND AN OPERATING MEMBER LOCATED OUTSIDE THE TUBULAR ELEMENTS AND MECHANICALLY CONNECTED TO THE WEDGE MEANS FOR SELECTIVELY MOVING SAID WEDGE MEANS INTO AND OUT OF THE INNER END OF SAID INNER TUBULAR ELEMENT THEREBY SELECTIVELY TO FORCE SAID SCORED SURFACES INTO LOCKING ENGAGEMENT WITH THE OUTER TUBULAR ELEMENT AND TO RELEASE SAID LOCKING ENGAGEMENT, RESPECTIVELY.