Umbrella frame and operating system

An umbrella structure (10), comprising: a central pole member (12) and having a longitudinal axis upper and lower ends (14, 16); main hub member (18) secured relative to said central pole member capable of sliding said main hub member between said lower end and said top; secondary hub member (30) secured to said member close to said upper end of post post; means (52, 70, 80, 90, 110) for supporting a canvas member (21); pulleys (130) for raising and lowering said main hub member along said pole member; and means (140, 150) for securing said member main hub in a stationary position along said post member, wherein said member main hub (18) includes a top surface (22) and a side surface ( 26) and in which said pulleys (130) includes at least one member of pulley (138) secured to said member and secondary hub (30) or said member central post (12), a support member (136) secured to said member main hub (18) and a line member (132) having first and second ends, being secured to said first end (134) to said support member (136), coupling said line member (132) cooperatively with said capstan member (138) and extending downwardly from said capstan member (138) toward said bottom end of post member (16), wherein said safety means includes a cam member (140) secured to said side surface (26) of said main hub member (18) and wherein said line member (132) engages cooperatively with said cam member (140) extending downwardly from said pulley member (138); characterized in that said cam member (140) it includes a pair of cams (141) secured pivotably to said side surface member main hub (26), said pair of cams (141) respectively a toothed inner side edge (142 ), looking said toothed inner side edges (142) each other in a rest position of the cam member (140).