Variable ratio drive system

A variable ratio drive system comprising:

• a variable diameter sprocket including:
• a support having a rotation axis;
• at least three sprocket portions having a longitudinal body provided with opposite ends:
• each said at least three sprocket portions being so mounted to said support as to be radially movable with respect to said rotation axis;
• each of said at least three sprocket portions is so configured that it may be selectively maintained in a desired radial position;
• each of said at least three sprocket portions comprising a dented portion provided near one of said opposite ends of said longitudinal body,
• a sprocket diameter changing mechanism configured to interact with said at least three sprocket portions to selectively maintain said sprocket portions in said desired radial position;
• said sprocket diameter changing mechanism including a fixed portion and a movable portion mounted to said fixed portion;
• said movable portion provided with a pushing surface so positioned and configured as to overcome a biasing action of a biasing element selectively maintaining a movable element of said sprocket portion is said desired radial position through a pushing action on said movable element of said sprocket portion;
• said pushing action causing the disengagement of said movable element from a stopping element of said support;
• said movable portion also including at least one guiding surface configured and sized to reposition said sprocket portion in a second desired position and to engage said movable element with a corresponding stopping element of said support.

A variable ratio drive system comprising:

• a variable diameter sprocket including:
• a support having a rotation axis and at least three sprocket portion retaining means each being provided with at least two sprocket portion position maintaining means;
• at least three sprocket portions, each being so mounted to a respective one of said at least three sprocket portion retaining means of said support as to be radially movable;
• each of said at least three sprocket portions includes means to interconnect with said at least two sprocket portion position maintaining means to selectively maintain the sprocket portion in a desired radial position;
• each sprocket portion also includes biasing means so mounted thereto to bias said interconnecting means towards said at least two sprocket portion position maintaining means;
• means for changing the diameter of said variable diameter sprocket, said sprocket diameter changing means including:
• a fixed portion;
• and
• a movable portion so mounted to said fixed portion as to be movable;
• said movable portion including means for overcoming a biasing action of said biasing means through a pushing action on said interconnecting means of said sprocket portion;
• said pushing action causing the disengagement of said interconnecting means from one of said sprocket portion retaining means;
• said movable portion also including at least one guiding means configured and sized to reposition said sprocket portion in a second desired position and to engage said interconnecting means with a corresponding sprocket portion retaining means.

A variable ratio drive system comprising:

• first and second variable diameter sprockets, each including:
• a support having a rotation axis and at least three radial apertures;
• each aperture being provided with at least two stopping element;
• at least three sprocket portions, each being so mounted to a respective one of said at least three radial aperture of said support as to be radially movable therein;
• each of said at least three sprocket portions includes a movable element configured and sized to interconnect with said at least two stopping element to selectively maintain the sprocket portion in a desired radial position;
• each sprocket portion also includes a biasing element mounted thereto to bias said movable element towards said at least two stopping element;
• first and second sprocket diameter changing mechanisms each including:
• a fixed portion;
• and
• a movable portion mounted to said fixed portion;
• said movable portion including a pushing surface so positioned and configured as to overcome a biasing action of said biasing element of a corresponding variable diameter sprocket through a pushing action on said movable element of said sprocket portion;
• said pushing action causing the disengagement of said movable element from one of said stopping element;
• said movable portion also including at least one guiding surface configured and sized to reposition said sprocket portion in a second desired position and to engage said movable element with a corresponding stopping element.