Transmission with radially inverted pulleys

A transmission comprising:

• a first split pulley defining a first axis and comprising first and second half-pulleys;
• a second split pulley defining a second axis and comprising third and fourth half-pulleys, wherein the second split pulley is nested within the first split pulley;
• a belt, wherein the belt is in contact with the first split pulley and the second split pulley, wherein a couple between the first and second half-pulleys exerts forces onto the belt that are radially directed inward toward the first axis, wherein a couple the third and fourth half-pulleys exerts forces onto the belt that are radially directed inward toward the second axis, and wherein a torque applied to the second split pulley causes a torque to be realized at the first split pulley via a compressive force transmitted along the belt from the second split pulley to the first split pulley;
• an input member;
• and
• an output member;
• wherein the second split pulley is rotatable about the second axis, wherein the first pulley is coupled to a mechanical ground such that the first split pulley is prevented from rotating about the first axis, wherein rotation of the input member results in movement of the second axis about the first axis, and wherein the output member is coupled to the second split pulley such that rotation of the second split pulley results in rotation of the output member and further such that a torque at the input member causes a torque to be realized at the output member,
• wherein the transmission is configured to control a transmission ratio of the transmission by adjusting a separation between the first and second half-pulleys and a separation between the third and fourth half-pulley, and wherein the transmission further comprises:
• a central gear that is coupled to the output member such that rotation of the central gear results in rotation of the output member, wherein the third and fourth half-pulleys comprise respective first and second ring gears having teeth that are in geared contact with the central gear such that rotation of the second split pulley results in rotation of the central gear, and wherein the third and fourth half-pulleys are arranged symmetrically about the central gear such that adjusting the separation between the third and fourth half-pulley results in symmetrical motion of the third and fourth half-pulleys toward or away from the central gear.

A transmission having a controllable transmission ratio, the transmission comprising:

• a first pulley defining a first axis, wherein the first pulley is a split pulley comprising first and second half-pulleys that are coupled to a mechanical ground such that the first pulley is prevented from rotating about the first axis;
• a second pulley defining a second axis, wherein the second pulley is nested within the first pulley, wherein the second pulley comprises third and fourth half pulleys that are rotatable about the second axis, and wherein the transmission is configured to control a transmission ratio of the transmission by adjusting a separation between the first and second half pulleys and a separation between the third and fourth half pulleys;
• a belt, wherein the belt is in contact with the first, second, third, and fourth half pulleys and wherein a torque applied to the second pulley causes a torque to be realized at the first pulley via a compressive force transmitted along the belt from the second pulley to the first pulley;
• an input member coupled to the second pulley such that rotation of the input member results in in movement of the second axis about the first axis;
• an output member coupled to the second pulley such that rotation of the second pulley results in rotation of the output member and further such that a torque at the input member causes a torque to be realized at the output member;
• and
• a central gear that is coupled to the output member such that rotation of the central gear results in rotation of the output member, wherein the third and fourth half-pulleys comprise respective first and second ring gears having teeth that are in geared contact with the central gear such that rotation of the second pulley results in rotation of the central gear, and wherein the third and fourth half pulleys are arranged symmetrically about the central gear such that adjusting the separation between the third and fourth half pulley results in symmetrical motion of the third and fourth half pulleys toward or away from the central gear.