pivotally connected to its corresponding rib at 56 the lower ends of links 51 55 are pivotally connected to slide ring 47 in the same manner that the ribs are pivotally connected to rib holder 40 as shown in fig5 thus the back strut links 53 and 54 pivot in a common vertical plane which is the vertical plane of ribs 33 and 34 and the vertical plane through the back edge 22 of the top fabric 20 for improved durability and stiffness each of the ribs and strut links just described is made as a double rib and double strut link as seen in fig5 for the purpose of the present description however each such pair of ribs and strut links will be referred to as a single member means are provided to hold back strut links 53 and 54 and back ribs 33 and 34 in a common vertical plane with the back edge 22 of top fabric 20 when the umbrella is open to prevent distortion as a result of the tension of the fabric and the eccentric position of pole 12 this holding means comprises a bracket 60 fixedly mounted on pole 12 by screw 61 so that wings 62 extend approximately in the vertical plane of back edge 22 of top fabric 20 the upper ends 63 and lower ends 64 of wings 62 are bent forward as seen in fig6 when the umbrella is opened strut links 53 and 54 pass upward behind the wings 62 and are thereby held in the desired common vertical plane as shown in fig1 and 4 and prevented from swinging forward under.