CONTINUOUSLY VARIABLE DRIVETRAIN
Drivetrains and frames for vehicles, equipment, machines, etc. Some embodiments of the drivetrains and frames are particularly suited for human powered machines, such as bicycles and exercise equipment. In some embodiments, a drivetrain includes a reciprocating crank coupled to a crank pivot. A lever couples to the crank via a lever pivot positioned on the crank. A lever stop cooperates with a lever guide surface to guide a motion of the lever as the lever pivots about the lever pivot. The lever and/or the crank are operably coupled to a drive pulley, idler pulley, and/or compound pulley. In some embodiments, a drive cable operably couples the lever and/or the crank to the drive pulley, idler pulley, and/or the compound pulley. In one embodiment, one or more pulleys couple to the lever's distal ends. In some embodiments, the drivetrain includes a wheel hub adapted to receive torque from the crank via a drive pulley.
1 . A cable-and-pulley system for a drivetrain, the cable-and-pulley system comprising:
a first pulley adapted to drive a hub;
a second pulley;
a first coupling member that couples the first pulley to the second pulley;
a third pulley;
a second coupling member that couples the second pulley to the third pulley;
wherein the first coupling member begins at the first pulley and ends at the second pulley; and
wherein the second coupling member begins at the second pulley and ends at a stationary structure.
2 . The cable-and-pulley system of claim 1 , wherein the first coupling comprises a first flexible tension member.
3 . The cable-and-pulley system of claim 1 , wherein the second coupling comprises a second flexible tension member.
4 . The cable-and-pulley system according to claim 2 or claim 3 , wherein the first and/or second flexible tension member comprises a cable.
5 . The cable-and-pulley system of claim 1 , wherein the second pulley comprises first and second grooves, wherein the first groove is adapted to receive the first coupling member and the second groove is adapted to receive the second coupling member.
6 . The cable-and-pulley system of claim 1 , wherein the third pulley comprises an idler pulley.
7 . The cable-and-pulley system of claim 6 , further comprising a crank operably coupled to the stationary structure.
8 . The cable-and-pulley system of claim 7 , wherein the third pulley is operably coupled to the crank.
9 . The cable-and-pulley system of claim 7 , wherein the crank operates in reciprocating motion.
10 . The cable-and-pulley system of claim 9 , wherein the first coupling member winds and unwinds from the drive pulley substantially synchronous with the reciprocating motion of the crank.
11 . The cable-and-pulley system of claim 9 , wherein the crank is configured to rotate less than 360 degrees.
12 . The cable-and-pulley system of claim 9 , wherein the second coupling member winds and unwinds from the second pulley substantially synchronous with the reciprocating motion of the crank.
13 . A pulley comprising:
a groove adapted to receive a flexible tension member;
a spiraling root that starts at a root of the groove and spirals through an angle of at least 360 degrees; and
wherein the largest diameter of the spiraling root is between 1.5 to 2 times greater than a diameter of the flexible tension member.
14 . The pulley of claim 13 , further comprising a bearing race integrally formed with the pulley.
15 . The pulley of claim 13 , further comprising a torque driver integrally formed with the pulley.
16 . The pulley of claim 13 , wherein the spiraling root is about 1.5 times greater than a diameter of the flexible tension member.
17 . A drive pulley comprising:
a groove for receiving a flexible tension member;
a torque driver integrally formed with the drive pulley;
a bearing race integrally formed with the drive pulley;
a spring hole configured to receive one end of a spring;
a cable hole configured to receive one end of the flexible tension member; and
one clamp hole configured to facilitate a fastening of the flexible tension member to the drive pulley.
18 . The drive pulley of claim 17 , wherein the torque driver is a hardened steel cylinder.
19 . The drive pulley of claim 17 , wherein the bearing race is hardened steel.
20 . The drive pulley of claim 17 , wherein the groove has a spiraling root that starts at a root of the groove and spirals through an angle of at least 360 degrees.