Driving system for a sewing machine

Claim 2

A driving system for a sewing machine comprising: a motor included in a motor housing having a stator fixed on said motor housing, a rotor rotatably arranged opposedly to said stator and a rotary shaft connected to said rotor and supported on said motor housing through a bearing; an electromagnetic coupling including a driving part mounted on one end of said rotary shaft of said motor and interlocked with said rotary shaft, and a driven part rotatably disposed inwardly of said driving part in spaced relationship therewith; an intermediate housing fitted on one end of said motor housing; an output shaft supported on said intermediate housing through a bearing and having said driven part mounted thereon; said electromagnetic coupling having an exciting coil fixed on said intermediate housing; an electromagnetic brake including a rotor connected to said output shaft; a tachometer generator including a rotor also connected to said output shaft; a command switch energized in reponse to a command by the operator; and means for regulating the electromagnetic force of said electromagnetic coupling and said electromagnetic brake in response to a signal either from said command switch or from said tachometer generator.

Claim 3

A driving system for the sewing machine according to claim 1, in which when said electromagnetic coupling is in an excited condition, said electromagnetic brake is in a de-energized state, and vice versa, both being controlled by said control means in response to signals from said tachometer generator and said command switch.

Claim 4

A driving system for the sewing machine according to claim 1, in which said command switch for regulating the excitation of said electromagnetic coupling and said electromagnetic brake through the control means is interlocked with an operating pedal of the sewing machine and is adapted to produce at least two different signals.

Claim 5

A driving system for the sewing machine according to claim 1, in which said electromagnetic coupling comprises a driving part including a drum axially projecting from an end of a flywheel mounted on one end of the rotary shaft of said motor and a driven part including a magnetic pole opposed in spaced relation with the inner periphery of said drum inwardly thereof, said driven part having a yoke directly secured to said output shaft, said driving part and said driven part of said electromagnetic coupling being excited through an exciting coil axially provided in said intermediate housing supporting said output shaft.

Claim 6

A driving system for the sewing machine according to claim 1, in which a plurality of cooling vanes are provided on the outer periphery of a flywheel mounted on the rotary shaft of said motor, and the cooling air is exhausted along the outer periphery of said motor housing axially thereof through an air passage comprising a plurality of ventilatioN holes provided on said intermediate housing and on an end bracket on the output shaft side of said motor.

Claim 7

A driving system for a sewing machine comprising: a motor having a housing, a stator fixed on said motor housing, a rotary shaft supported by said motor housing, and a rotor disposed on said rotary shaft and arranged rotatably and oppositely to said stator; an intermediate housing fitted on one end of said motor housing; an output shaft supported by said intermediate housing and arranged on the same axis as said rotary shaft of said motor; an electromagnetic coupling including a driving part mounted on one end of said rotary shaft of said motor, a driven part mounted on said output shaft and arranged rotatably and oppositely to said driving part with a gap therebetween, and an exciting coil fixed inwardly to one of the side walls of said intermediate housing for producing magnetic flux passing a magnetic path consisting of said driving part, said driven part and said gap; an electromagnetic brake including an exciting coil fixed outwardly to said one of the side walls of said motor housing, and a magnetic body, provided oppositely to said exciting coil, having a friction member and supported by a spring support fixed on said output shaft; a tachometer generator disposed within said intermediate housing for detecting the rotational speed of said output shaft; a command switch energized in response to a command by an operator; and means for regulating the electromagnetic forces of said electromagnetic coupling and said electromagnetic brake in response to at least one of signals from said command switch and from said tachometer generator.

Claim 8

A driving system for a sewing machine comprising: a motor having a housing, a stator fixed on said motor housing, a rotary shaft supported by said motor housing, and a rotor disposed on said rotary shaft and arranged rotatably and oppositely to said stator; an intermediate housing fitted on one end of said motor housing; an output shaft supported by said intermediate housing and arranged on the same axis as said rotary shaft of said motor; an electromagnetic coupling including a driving part mounted on one end of said rotary shaft of said motor, a driven part mounted on said output shaft and arranged rotatably and oppositely to said driving part with a gap therebetween, and an exciting coil fixed inwardly to one of the side walls of said intermediate housing for producing magnetic flux passing a magnetic path consisting of said driving part, said driven part and said gap; an electromagnetic brake including an exciting coil fixed outwardly to said one of the side walls of said motor housing, and a magnetic body, provided oppositely to said exciting coil, having a friction member and supported by a spring support fixed on said output shaft; a tachometer generator disposed within said intermediate housing for detecting the rotational speed of said output shaft; a command switch energized in response to a command by an operator; and means for regulating the electromagnetic forces of said electromagnetic coupling and said electromagnetic brake in response to at least one of signals from said command switch and from said tachometer generator.

Claim 9

A driving system according to claim 6, wherein when said electromagnetic coupling is in an excited condition, said electromagnetic brake is in a de-energized condition and when said electromagnetic coupling is in a de-energized condition, said electromagnetic brake is in an energized condition, both said electromagnetic coupling and said electromagnetic brake being controlled by said control means in response to signals from said tachometer generator and said command switch.

Claim 10

A driving system according to claim 7, wherein said command switch provides a plurality of predetermined output signals in accordance with an operating pedal position of the sewing machine, comparison means for comparing the output signals of said command switch and said tachometer generator for providing an output signal indicative of the difference therebetween, and first and second means for respectively controlling the excitation condition of said electromagnetic coupling and said electromagnetic brake in accordance with the output signal of said comparison means.

Claim 11

A driving system according to claim 8, wherein said first means includes power supply means connected to thyristor means for providing an exciting signal to said electromagnetic coupling and phase control means responsive to the output signal of said comparison means for controlling the firing phase of said thyristor means, and said second means includes power supply means connected to thyristor means for providing an exciting signal to said electromagnetic brake and converter means responsive to the output signal of said comparison means for providing an output signal to a phase control means for controlling the phase of firing of said thyristor means.

Claim 12

A driving system according to claim 6, wherein said command switch for regulating the excitation of said electromagnetic coupling and said electromagnetic brake through the control means is interlocked with an operating pedal of the sewing machine and is adapted to produce at least two different signals.

Claim 13

A driving system for a sewing machine according to claim 6, wherein said driving part comprises a drum axially projecting from a flywheel mounted on said one end of the rotary shaft of said motor, and said driven part includes a magnetic pole arranged inside of said drum in spAced and opposite relation to the inner peripheral surface of said drum and secured to said output shaft through a yoke fixedly secured to said output shaft.

Claim 14

A driving system according to claim 6, wherein a plurality of cooling vanes are provided on the outer periphery of a flywheel mounted on the rotary shaft of said motor, and cooling air is exhausted along the outer periphery of said motor housing axially thereof through an air passage comprising a plurality of ventilation holes provided on said intermediate housing and on an end bracket on the output shaft side of said motor.