Patent ID: 8439176

Claim:
A cord coupling for engaging and disengaging a driving shaft with a driven hub disposed concentrically thereover and spaced therefrom comprising: a driving shaft configured with three or more longitudinal pairs of grooves provided in an outer drive surface thereof; three or more cords made of an elastic material; each pair of grooves having a deep groove having a deep track of a depth sufficient for a cord to reside therein out of contact with the driven hub disposed over the driving shaft, and a shallow groove adjacent to the deep groove having a shallow depth sufficient for a cord to reside therein with a portion of the cord extending beyond the outer drive surface in an amount sufficient to bridge the space between the driving shaft and the driven hub, each cord being secured and tightened within each shallow groove for a full length thereof when the driving shaft is not rotating, the deep groove being disposed adjacent to the shallow groove in a direction of rotation of the driving shaft, such that upon rotation of the driving shaft, the three or more cords are elastically displaced from the deep groove into the shallow groove, the three or more cords filling the space between the driving shaft and the driven hub which is thereby locked by the three or more cords into rotation with the driving shaft, and such that rotating the driven hub in a direction opposite to the rotating direction displaces each cord into the deep groove such that the driven hub is disengaged and removable from the driving shaft.