A variable speed drive mechanism includes a fixed disk concentric with, attached to, and rotatable with a shaft about a central axis. A plurality of pulley segments are supported by the fixed disk, and are moveable relative to the fixed disk in a radial direction relative to the central axis. A moveable disk is concentric with the shaft, and is rotatably moveable about the shaft relative to the fixed disk. The moveable disk defines a spiral groove having a center concentric with the shaft. The pulley segments include a guided groove portion engaged with and moveable along the spiral groove. Rotation of the moveable disk relative to the fixed disk rotates the spiral groove about the central axis relative to the pulley segments, thereby moving the guided groove portions along the spiral groove to move the pulley segments radially relative to the central axis.

A variable speed drive mechanism includes a fixed disk concentric with, attached to, and rotatable with a shaft about a central axis. A plurality of pulley segments are supported by the fixed disk, and are moveable relative to the fixed disk in a radial direction relative to the central axis. A moveable disk is concentric with the shaft, and is rotatably moveable about the shaft relative to the fixed disk. The moveable disk defines a spiral groove having a center concentric with the shaft. The pulley segments include a guided groove portion engaged with and moveable along the spiral groove. Rotation of the moveable disk relative to the fixed disk rotates the spiral groove about the central axis relative to the pulley segments, thereby moving the guided groove portions along the spiral groove to move the pulley segments radially relative to the central axis.

A stepless transmission transmits a driving force by an endless transmission member (5) wound around a V-groove (6) of an input pulley (1). The input pulley (1) has moving parts (9) which are fastened by threaded engagement so as to be axially movable with respect to a transmission case (3) and have ring gears (10), to which rotation can be input from the outer periphery sides, and pulley half discs (13) which are relatively rotatable with respect to the moving parts (9), which axially move integrally with the moving parts (9) and which are contactable with an endless transmission member (5). The pulley half discs (13) and an input shaft 2, which is disposed at the center of the pulley half discs (13), rotate together as one piece. The ring gears (10) are each rotationally driven from a drive source of the same drive member.

A stepless transmission transmits a driving force by an endless transmission member (5) wound around a V-groove (6) of an input pulley (1). The input pulley (1) has moving parts (9) which are fastened by threaded engagement so as to be axially movable with respect to a transmission case (3) and have ring gears (10), to which rotation can be input from the outer periphery sides, and pulley half discs (13) which are relatively rotatable with respect to the moving parts (9), which axially move integrally with the moving parts (9) and which are contactable with an endless transmission member (5). The pulley half discs (13) and an input shaft 2, which is disposed at the center of the pulley half discs (13), rotate together as one piece. The ring gears (10) are each rotationally driven from a drive source of the same drive member.

This new mechanism can effect a smooth change in speed ratio of a variety of machines, namely, in those of automobile gear boxes, motorcycles, bicycles or generally any system that is designed for transferring power which is subject to change in ratio. This idea, however, consists of a pulley that is capable of changing ratio without needing to halt or going through a step-off phase. This pulley, which I call Fragmentary pulley for argument's sake, is made up of, 10, 20, 24, 36 fragments. These fragments can move on path toward the center of the pulley and vice versa, thus varying the diameter of the pulley. In other words, the change in ratio will occur as result of this movement. The aforementioned process is the very foundation of my fragmentary pulley, though. the addition of another pulley with the same structure, spinning the opposite direction, augments the whole process. In short, when the input pulley is working with the smallest diameter, the secondary pulley will be working with its biggest diameter. In other words, the greater speed causes the input pulley to expand and the output pulley to contract.

This new mechanism can effect a smooth change in speed ratio of a variety of machines, namely, in those of automobile gear boxes, motorcycles, bicycles or generally any system that is designed for transferring power which is subject to change in ratio. This idea, however, consists of a pulley that is capable of changing ratio without needing to halt or going through a step-off phase. This pulley, which I call Fragmentary pulley for argument's sake, is made up of, 10, 20, 24, 36 fragments. These fragments can move on path toward the center of the pulley and vice versa, thus varying the diameter of the pulley. In other words, the change in ratio will occur as result of this movement. The aforementioned process is the very foundation of my fragmentary pulley, though. the addition of another pulley with the same structure, spinning the opposite direction, augments the whole process. In short, when the input pulley is working with the smallest diameter, the secondary pulley will be working with its biggest diameter. In other words, the greater speed causes the input pulley to expand and the output pulley to contract.

In a pulley apparatus, belt supporting portions of belt support pieces, which support a belt from a radially inside thereof, are arranged along a circumferential direction of a power shaft and each have a predetermined circumferential length. In a pulley driven mode, the belt support pieces rotate about corresponding first supporting members in a direction making the belt supporting portions become closer to the power shaft with second supporting members being relatively moved in corresponding elongated holes toward radially outer ends thereof, causing the belt supporting portions to be reduced in radius. In a pulley driving mode, the belt support pieces rotate about the corresponding first supporting members in a direction making the belt supporting portions become further from the power shaft with the second supporting members being relatively moved in the corresponding elongated holes toward radially inner ends thereof, causing the belt supporting portions to be increased in radius.

In a pulley apparatus, belt supporting portions of belt support pieces, which support a belt from a radially inside thereof, are arranged along a circumferential direction of a power shaft and each have a predetermined circumferential length. In a pulley driven mode, the belt support pieces rotate about corresponding first supporting members in a direction making the belt supporting portions become closer to the power shaft with second supporting members being relatively moved in corresponding elongated holes toward radially outer ends thereof, causing the belt supporting portions to be reduced in radius. In a pulley driving mode, the belt support pieces rotate about the corresponding first supporting members in a direction making the belt supporting portions become further from the power shaft with the second supporting members being relatively moved in the corresponding elongated holes toward radially inner ends thereof, causing the belt supporting portions to be increased in radius.

A segmented pulley defining an outer peripheral surface for engaging an endless member of a segmented pulley transmission is provided. The segmented pulley comprises: a plurality of pulley segments configured to be sequentially movable between an engaged region and a disengaged region to transition the endless member between the segmented pulley and a concentric pulley in the segmented pulley transmission, each of the pulley segments having a body defining a portion of the outer peripheral surface. The plurality of pulley segments includes a transition segment having an integrated support extending from the body of the transition segment, the integrated support being configured to support the endless member when transitioning the endless member between the segmented pulley and the adjacent pulley in the segmented pulley transmission. A segmented pulley transmission comprising the segmented pulley is further provided.

A segmented pulley defining an outer peripheral surface for engaging an endless member of a segmented pulley transmission is provided. The segmented pulley comprises: a plurality of pulley segments configured to be sequentially movable between an engaged region and a disengaged region to transition the endless member between the segmented pulley and a concentric pulley in the segmented pulley transmission, each of the pulley segments having a body defining a portion of the outer peripheral surface. The plurality of pulley segments includes a transition segment having an integrated support extending from the body of the transition segment, the integrated support being configured to support the endless member when transitioning the endless member between the segmented pulley and the adjacent pulley in the segmented pulley transmission. A segmented pulley transmission comprising the segmented pulley is further provided.