| 摘要 |
A device for varying, in an exercise apparatus, forces and movements between a movement organ and resistive means, comprises a pulley; a movable structure, bearing a pivot pin for the rotation of the pulley, whereto is applied a traction force correlated to the muscle effort of the person performing the exercise; a cable element wound on the pulley, forming a pair of parallel branches, whereof one is connected to the resistive means, the other to a bar able to move within a guide. The device comprises selective fastening means which, in a first operative condition, anchor the bar to the guide opposing twice the force of the resistive means to the pin; and which, in the second operative condition, allow the bar to translate until it abuts against the movable structure, opposing a reaction force equal to the reaction force of the resistive means to the pin.
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