SYSTEM FOR ADJUSTING A LOAD FOR GYMNASTIC MACHINES AND TENSIONING AND RETURNING DEVICE OR SAID SYSTEM FOR ADJUSTING

A system for adjusting a load movable along a vertical direction for gymnastic machines provided with a frame, said system comprising a supporting member of said mobile load, provided with a plurality of adjustment holes, said movable load consisting of a plurality of weights arranged stacked and selectable, a selector member to be inserted in one of said adjustment holes of said supporting member, in order to select a group of said weights, adjusting said movable load and a string having an end fixed to said selector member, said system comprising tensioning means of said string, to keep said string in tension when said selector member is inserted in one hole of said plurality of adjustment holes, and to return said selector member when it is disengaged from said plurality of adjustment holes The system also concerns a tensioning and returning device.