Rotation control device

Claim 2

A rotation control device comprising means including a pulley mounted on a driving shaft which is rotated in a predetermined direction at a constant speed, a pulley mounted on a driven shaft which is desired to be driven in a fixed relation with the phase of a reference signal, one of said pulleys being a conical pulley and the other being an intermediately bulged pulley, and a torque-transmitting elastic belt trained around said pulleys for transmitting the rotation of said driving shaft to said driven shaft, means for deriving a signal which is in synchronism with the phase of rotation of said driven shaft, means for comparing the phase of the signal which is in synchronism with the phase of rotation of said driven shaft with the phase of said reference signal for thereby deriving a control signal which represents the phase difference between said signals, and means operative in response to the application of said control signal to impart a corresponding brake torque to said driven shaft for thereby automatically varying the engaging position between said torquetransmitting belt and said conical pulley.

Claim 3

A rotation control device comprising means including a pulley mounted on a driving shaft which is rotated in a predetermined direction at a constant speed, a pulley mounted on a driven shaft which is desired to be driven in a fixed relation with the phase of a reference signal, at least one of said pulleys being a conical pulley, and a torque-transmitting elastic belt trained around said pulleys for transmitting the rotation of said driving shaft to said driven shaft, one of said pulleys being so adapted as to be adjustably movable in the axial direction of the shaft on which it is mounted, means for deriving a signal which is in synchronism with the phase of rotation of said driven shaft, means for comparing the phase of the signal which is in synchronism with the phase of rotation of said driven shaft with the phase of said reference signal for thereby deriving a control signal which represents the phase difference between said signals, and means operative in response to the application of said control signal to impart a corresponding brake torque to said driven shaft for thereby automatically varying the engaging position between said torque-transmitting belt and said conical pulley.

Claim 4

A rotation control device comprising means including a pulley mounted on a driving shaft which is rotated in a predetermined direction at a constant speed, a pulley mounted on a driven shaft which is desired to be driven in a fixed relation with the phase of a reference signal, at least one of said pulleys being a conical pulley, and a torque-transmitting elastic belt trained around said pulleys for transmitting the rotation of said driving shaft to said driven shaft, one of said pulleys being so adapted as to be adjustably movable in the axial direction of the shaft on which it is mounted, means for deriving a signal which is in synchronism with the phase of rotation of said driven shaft, means for comparing the phase of the signal which is in synchronism with the phase of rotation of said driven shaft with the phase of said reference signal for thereby deriving a control signal which represents the phase difference between said signals, and means operative in response to the application of said control signal to impart a corresponding brake torque to said driven shaft for thereby automatically varying the engaging position between said torque-transmitting belt and said conical pulley.

Claim 5

A rotation control device comprising means including a pulley mounted on a driving shaft which is rotated in a predetermined direction at a constant speed, a pulley mounted on a driven shaft which is desired to be driven in a fixed relation with the phase of a predetermined reference signal, at least one of saiD pulleys being a conical pulley, and a torque-transmitting resilient belt trained around said pulleys for transmitting the rotation of said driving shaft to said driven shaft, means for deriving a signal which is in synchronism with the phase of rotation of said driven shaft, means for comparing the phase of the signal which is in synchronism with the phase of rotation of said driven shaft with the phase of said reference signal for thereby deriving a control signal which represents the phase difference between said signals, and brake means operative in response to the application of said control signal to impart a corresponding brake torque to said driven shaft, said brake means including a squirrel-cage induction rotor fixed to said driven shaft and an exciting iron core for applying to said rotor a DC magnetic field of the strength corresponding to said control signal, said brake torque imparted to said driven shaft by said brake means being operative to automatically vary the engaging position between said torque-transmitting belt and said conical pulley.

Claim 6

A rotation control device comprising means including a pulley mounted on a driving shaft which is rotated in a predetermined direction at a constant speed, a pulley mounted on a driven shaft which is desired to be driven in a fixed relation with the phase of a predetermined reference signal, at least one of saiD pulleys being a conical pulley, and a torque-transmitting resilient belt trained around said pulleys for transmitting the rotation of said driving shaft to said driven shaft, means for deriving a signal which is in synchronism with the phase of rotation of said driven shaft, means for comparing the phase of the signal which is in synchronism with the phase of rotation of said driven shaft with the phase of said reference signal for thereby deriving a control signal which represents the phase difference between said signals, and brake means operative in response to the application of said control signal to impart a corresponding brake torque to said driven shaft, said brake means including a squirrel-cage induction rotor fixed to said driven shaft and an exciting iron core for applying to said rotor a DC magnetic field of the strength corresponding to said control signal, said brake torque imparted to said driven shaft by said brake means being operative to automatically vary the engaging position between said torque-transmitting belt and said conical pulley.

Claim 7

A rotation control device comprising means including a pulley mounted on a driving shaft which is rotated in a predetermined direction at a constant speed, a pulley mounted on a driven shaft which is desired to be driven in a fixed relation with the phase of a reference signal, at least one of said pulleys being a conical pulley, and a torque-transmitting elastic belt trained around said pulleys for transmitting the rotation of said driving shaft to said driven shaft, means for deriving a signal which is in synchronism with the phase of rotation of said driven shaft, means for comparing the phase of the signal which is in synchronism with the phase of rotation of said driven shaft with the phase of said reference signal for thereby deriving a control signal which represents the phase difference between said signals, and means operative in response to the application of said control signal to impart a corresponding brake torque to said driven shaft for thereby automatically varying the engaging position between said torque-transmitting belt and said conical pulley.

Claim 8

A rotation control device comprising means including a pulley mounted on a driving shaft which is rotated in a predetermined direction at a constant speed, a pulley mounted on a driven shaft which is desired to be driven in a fixed relation with the phase of a reference signal, at least one of said pulleys being a conical pulley, and a torque-transmitting elastic belt trained around said pulleys for transmitting the rotation of said driving shaft to said driven shaft, means for deriving a signal which is in synchronism with the phase of rotation of said driven shaft, means for comparing the phase of the signal which is in synchronism with the phase of rotation of said driven shaft with the phase of said reference signal for thereby deriving a control signal which represents the phase difference between said signals, and means operative in response to the application of said control signal to impart a corresponding brake torque to said driven shaft for thereby automatically varying the engaging position between said torque-transmitting belt and said conical pulley.

Claim 9

A rotation control device according to claim 4, in which said torque-transmitting elastic belt is stabilized at a position slightly protruding beyond one end of said conical pulley when the brake torque imparted to said driven shaft is zero or has a suitable biasing value.

Claim 10

A rotation control device comprising means including a conical pulley mounted on a driving shaft which is rotated in a predetermined direction at a constant speed, a conical pulley mounted on a driven shaft which is desired to be driven in a fixed relation with the phase of a reference signal, said conical pulleys being mounted in directions opposite to each other, and a torque-transmitting elastic belt trained around said conical pulleys for transmitting the rotation of said driving shaft to said driven shaft, means for deriving a signal which is in synchronism with the phase of rotation of said driven shaft, means for comparing the phase of the signal which is in synchronism with the phase of rotation of said driven shaft with the phase of said reference signal for thereby deriving a control signal which represent the phase difference between said signals, and means operative in response to the application of said control signal to impart a corresponding brake torque to said driven shaft for thereby automatically varying the engaging position between said torque-transmitting belt and one of said conical pulleys.

Claim 11

A rotation control device comprising means including a conical pulley mounted on a driving shaft which is rotated in a predetermined direction at a constant speed, a conical pulley mounted on a driven shaft which is desired to be driven in a fixed relation with the phase of a reference signal, said conical pulleys being mounted in directions opposite to each other, and a torque-transmitting elastic belt trained around said conical pulleys for transmitting the rotation of said driving shaft to said driven shaft, means for deriving a signal which is in synchronism with the phase of rotation of said driven shaft, means for comparing the phase of the signal which is in synchronism with the phase of rotation of said driven shaft with the phase of said reference signal for thereby deriving a control signal which represent the phase difference between said signals, and means operative in response to the application of said control signal to impart a corresponding brake torque to said driven shaft for thereby automatically varying the engaging position between said torque-transmitting belt and one of said conical pulleys.

Claim 12

A rotation control device according to claim 6, in which said two conical pulleys disposed in the directions opposite to each other have cone angles different from each other, and said torque- transmitting belt is stabilized at a position slightly protruding beyond one end of one of said conical pulleys when the brake torque imparted to said driven shaft is zero or has a suitable biasing value.

Claim 13

A rotation control device for use in a magnetic recordiNg and reproducing apparatus of the kind having a magnetic tape and a rotary head assembly including therein a plurality of magnetic transducers for the recording and reproduction of a television signal; said device comprising means for deriving a control signal responsive to the synchronizing signal in said television signal, a single drive source for delivering a drive force to drive both said magnetic tape and said rotary head assembly, said drive source being an AC synchronous motor, a current-controlled stepless speed change mechanism connecting the shaft of said rotary head assembly with the shaft of said drive source, said stepless speed change mechanism comprising a pulley fixedly mounted on the shaft of said rotary head assembly, a pulley fixedly mounted on the shaft of said drive source, at least one of said pulleys being a conical pulley, a torque-transmitting resilient belt trained around said pulleys, and brake means mounted on the shaft of said rotary head assembly, means for deriving a signal which is in synchronism with the phase of rotation of the shaft of said rotary head assembly, means for comparing the phase of the signal which is in synchronism with the phase of rotation of the shaft of said rotary head assembly with the phase of said control signal for thereby deriving a second control signal, and means operative in response to the application of said second control signal to control said brake means for thereby imparting a brake torque to the shaft of said rotary head assembly and automatically varying the engaging position between said torque-transmitting belt and said conical pulley.

Claim 14

A rotation control device for use in a magnetic recordiNg and reproducing apparatus of the kind having a magnetic tape and a rotary head assembly including therein a plurality of magnetic transducers for the recording and reproduction of a television signal; said device comprising means for deriving a control signal responsive to the synchronizing signal in said television signal, a single drive source for delivering a drive force to drive both said magnetic tape and said rotary head assembly, said drive source being an AC synchronous motor, a current-controlled stepless speed change mechanism connecting the shaft of said rotary head assembly with the shaft of said drive source, said stepless speed change mechanism comprising a pulley fixedly mounted on the shaft of said rotary head assembly, a pulley fixedly mounted on the shaft of said drive source, at least one of said pulleys being a conical pulley, a torque-transmitting resilient belt trained around said pulleys, and brake means mounted on the shaft of said rotary head assembly, means for deriving a signal which is in synchronism with the phase of rotation of the shaft of said rotary head assembly, means for comparing the phase of the signal which is in synchronism with the phase of rotation of the shaft of said rotary head assembly with the phase of said control signal for thereby deriving a second control signal, and means operative in response to the application of said second control signal to control said brake means for thereby imparting a brake torque to the shaft of said rotary head assembly and automatically varying the engaging position between said torque-transmitting belt and said conical pulley.

Claim 15

A rotation control device according to claim 8, in which both said pulleys are conical pulleys.

Claim 16

A rotation control device according to claim 8, in which one of said pulleys in a conical pulley and the other is an intermediately bulged pulley.