Pivotal back for a sandal style shoe

A pivotal back for a sandal style shoe adapted to mount on a sole (41), and the pivotal back comprising:

• a back (10) having a pivotal end;
• a pivot device attached to the back (10) and comprising
• a pivot chamber (11), which is a cylindrical tube, formed on the pivotal end of the back (10) and having a closed end (12), an open end (15) with an edge and a central hole (121) defined on the closed end (12);
• and
• a resilient element mounted inside the pivot chamber (11) to provide a restitution force to the back (10);
• and
• a hinge (30) adapted to attach to the sole (41) and comprising
• a U-shaped connecting bar (31);
• two parallel wings (32) extending outward and downward from the U-shaped connecting bar (31), wherein a space is formed between the two parallel wings (32) to rotatably receive the pivot chamber (11) of the resilient pivot device and a hole (321) is defined in each wing (32) to align with the central hole (121) in the closed end (12);
• and
• a pivot pin (36) passing through the holes (321) of the wings (32), the central hole (121) in the closed end (12) of the pivot chamber (11) and the resilient element to rotatably and axially assemble all elements together.