Collapsible umbrellas

Claim 1

IN A TELESCOPING UMBRELLA FRAME COMPRISING A STICK HAVING A CROWN, A PLURALITY OF ANGULARLY SPACED TELESCOPABLE RIBS EACH PIVOTED AT ONE EXTREMITY TO SAID CROWN, EACH OF SAID RIBS HAVING A FIRST MEMBER PIVOTED TO SAID CROWN AND A SECOND MEMBER SLIDABLE RELATIVELY TO SAID FIRST MEMBER, A MAIN SLIDER MOVABLE ALONG SAID STICK TOWARD AND AWAY FROM SAID CROWN, A PLURALITY OF ANGULARLY SPACED MAIN STRUTS EACH ARTICULATED AT ONE EXTREMITY TO SAID MAIN SLIDER AND AT ITS OTHER EXTREMITY TO A RESPECTIVE ONE OF SAID RIBS, AN AUXILIARY SLIDER MOVABLE ALONG SAID STICK AND DISPOSED BETWEEN SAID MAIN SLIDER AND SAID CROWN, AND A PLURALITY OF ANGULARLY SPACED AUXILIARY STRUTS EACH PIVOTED TO SAID AUXILIARY SLIDER AT ONE END AND AT ITS OTHER END TO A RESPECTIVE MAIN STRUT WHEREBY SIMULTANEOUS DISPLACEMENT OF SAID SLIDERS TOWARD SAID CROWN FROM RESPECTIVE EXTREME POSITIONS REMOTE THEREFROM WILL EFFECT A TELESCOPING OF SAID MEMBERS OF EACH RIB; THE COMBINATION THEREWITH OF A CLAMPING ELEMENT PIVOTED TO ONE OF SAID MEMBERS OF AT LEAST ONE OF SAID RIBS FOR LOCKING SAID MEMBERS AGAINST RELATIVE DISPLACEMENT, SAID ELEMENT BEING SWINGABLE ABOUT A PIVOTAL AXIS TRANSVERSE TO THE DIRECTION OF RELATIVE DISPLACEMENT OF THE MEMBERS OF SAID ONE RIB WHILE BEING FORMED WITH AN ARCUATE CLAMPING SURFACE ECCENTRIC WITH RESPECT TO SAID AXIS AND ENGAGEABLE WITH THE OTHER MEMBER OF SAID ONE RIB FOR ENTRAINMENT THEREBY TO WEDGE THE MEMBERS OF SAID ONE RIB AGAINST EACH OTHER AND RESTRAIN SAID AUXILIARY SLIDER FROM MOVEMENT ALONG SAID STICK SIMULTANEOUSLY WITH SAID MAIN SLIDER IN ONE OPERATIVE POSITION OF ELEMENT, AND ABUTMENT MEANS ON SAID ELEMENT ENGAGEABLE BY THE ASSOCIATED MAIN STRUT FOR SWINGING AND MAINTAINING SAID CLAMPING SURFACE OUT OF ENGAGEMENT WITH SAID OTHER MEMBER IN ANOTHER OPERATIVE POSITION OF SAID ELEMENT UPON SAID ASSOCIATED MAIN STRUT BEING DISPOSED SUBSTANTIALLY PARALLEL TO SAID ONE RIB FOR PERMITTING SAID SIMULTANEOUS DISPLACEMENT OF SAID SLIDERS, SAID ELEMENT HAVING A CENTER OF GRAVITY LOCATED BETWEEN SAID AXIS AND SAID OTHER MEMBER WHEREBY SAID CLAMPING SURFACE MAY BE URGED BY GRAVITATIONAL FORCE AGAINST SAID OTHER MEMBER.