Claims
- 1. In a sewing machine of the type provided with pattern selector means operated by the user for implementing selected ones of a plurality of differently configured stitch-patterns, in combination, electromechanical thread-tension varying means operative for varying the tension of the thread fed to the sewing needle of the machine in response to a variable electrical tension command signal; and tension command signal generating means operative for furnishing to the electromechanical thread-tension varying means an electrical tension command signal, and including means for automatically selecting different values for the tension command signal, and thereby different values of thread tension produced by the thread-tension varying means, without the user of the machine needing to separately command said different values for the tension command signal, the means automatically selecting different values for the tension command signal being responsive to user operation of the pattern selector means, whereby the automatic selection of different values for the tension command signal is performed automatically as an incident to the user selecting different stitch-patterns.
- 2. In a sewing machine as defined in claim 1, furthermore including auxiliary user-operated selecting means operable by the user for altering the automatically selected values for the tension command signal when the user wishes to deviate from the automatically selected values.
- 3. In a sewing machine as defined in claim 2, the tension command signal generating means comprising a voltage divider comprised of at least two series-connected resistor stages, one resistor stage comprising a plurality of parallel-connected circuit branches each of which includes a resistor of different respective resistance value and a switch which closes in response to selection of a respective pattern by the user-operated pattern selector means, the other resistor stage comprising a potentiometer having an adjustable wiper manually adjustable by the user and constituting the auxiliary selecting means operated by the user when the user wishes to deviate from the automatically selected values for the tension command signal, the tension command signal being produced at the wiper of the potentiometer.
- 4. In a sewing machine as defined in claim 2, the sewing machine being provided with a user-operated presser-foot member moved by the user to a first setting to lift the cloth presser foot of the machine up out of engagement with sewn cloth and moved by the user to a second setting to lower the cloth presser foot of the machine down into engagement against sewn cloth, the means for automatically selecting different values for the tension command signal including means automatically changing the value of the tension command signal when the user-operated presser-foot member is moved to the first setting thereof.
- 5. In a sewing machine as defined in claim 3, the sewing machine being provided with a user-operated presser-foot member moved by the user to a first setting to lift the cloth presser foot of the machine up out of engagement with sewn cloth and moved by the user to a second setting to lower the cloth presser foot of the machine down into engagement against sewn cloth, said voltage divider furthermore including a third resistor stage, the means for automatically changing the value of the tension command signal furthermore including switch means operative when the presser-foot member is in its second setting for connecting the first and second resistor stages in series but operative when the presser-foot member is in its first setting for connecting the second and third resistor stages in series.
- 6. In a sewing machine as defined in claim 1, the electromechanical thread-tension varying means having a range of settings respectively producing differing amounts of thread tension and furthermore including a feedback transducer cooperating with the thread-tension varying means and generating a feedback signal indicating the present setting of the thread-tension varying means, and means automatically changing the setting of the thread-tension varying means in dependence upon the discrepancy between the tension command signal and the feedback signal.
- 7. In a sewing machine as defined in claim 6, the electromechanical thread-tension varying means including a pressure-applying structure operative for tensioning thread by applying pressure to the thread, the feedback transducer being a pressure transducer generating a signal indicating the amount of pressure applied by the pressure-applying structure.
- 8. In a sewing machine as defined in claim 6, the electromechanical thread-tension varying means including a rotary structure rotatable for varying the tension applied to thread, the feedback transducer being an angular position transducer generating a feedback signal indicating the angular position of the rotary structure.
- 9. In a sewing machine as defined in claim 1, the electromechanical thread-tension varying means comprising a pair of cooperating tension disks between which thread to be tension is guided, a solenoid comprising a plunger-type armature and a solenoid winding encircling the plunger-type armature, the magnitude of electrical current flowing through the solenoid winding determining the force with which the plunger-type armature is urged, the solenoid being provided with two confining portions between which the tension disks are confined, one confining portion being provided on the armature and the other being stationary.
- 10. In a sewing machine as defined in claim 1, the electromechanical thread-tension varying means comprising a pair of cooperating tension disks between which thread to be tensioned is guided, a compression spring located to press one of the tension disks against the other, and electrically controlled pressing means pressing the compression spring against said one of the tension disks with an adjustable pressing force serving to vary the precompression of the compression spring, the electrically controlled pressing means including a reversible electric motor, a threaded shaft driven by the motor, an internally threaded pressing member threaded on the threaded shaft and pressing the compression spring against said one of the tension disks, rotation of the threaded shaft resulting in displacement of the internally threaded pressing member along the length of the shaft and thereby resulting in adjustment of the precompression of the compression spring.
- 11. In a sewing machine provided with a user-operated presser-foot member moved by the user to a first setting to lift the cloth presser foot of the machine up out of engagement with sewn cloth and moved by the user to a second setting to lower the cloth presser foot of the machine down into engagement against sewn cloth, in combination, electromechanical thread-tension varying means operative for varying the tension of the thread fed to the sewing needle of the machine in response to a variable electrical tension command signal; and tension command signal generating means operative for furnishing to the electromechanical thread-tension varying means an electrical tension command signal, and including means for automatically selecting different values for the tension command signal, and thereby different values of thread tension produced by the thread-tension varying means, without the user of the machine needing to separately command said different values for the tension command signal, the means for automatically selecting different values for the tension command signal including means responsive to the setting of the user-operated presser-foot member.
- 12. In a sewing machine as defined in claim 11, the means responsive to the setting of the user-operated presser-foot member comprising means operative when the presser-foot member is moved by the user to the first setting thereof for automatically establishing a predetermined value for the tension command signal; and furthermore including auxiliary user-operated selecting means operable by the user for altering the tension command signal value automatically selected in response to the first setting of the presser-foot member, whereby if the machine is used for basting with the cloth presser foot in raised position thread tension is nevertheless maintained and is furthermore user-adjustable.
- 13. In a sewing machine of the type provided with a pattern memory consisting of addressable storage locations which store stitch-control data for at least one stitch-pattern, the pattern memory having stitch-control data outputs at which appear the stitch-control data contained in a memory storage location when that storage location is addressed, the storage locations furthermore storing tension-control data and the pattern memory additionally having tension-control data outputs at which appear the tension-control data contained in a memory storage location when that storage location is addressed, in combination, electromechanical thread-tension varying means operative for varying the tension of the thread fed to the sewing needle of the machine in response to a variable electrical tension command signal; and tension command signal generating means operative for furnishing to the electromechanical thread-tension varying means an electrical tension command signal, and including means for automatically selecting different values for the tension command signal, and thereby different values of thread tension produced by the thread-tension varying means, without the user of the machine needing to separately command said different values for the tension command signal, the means for automatically selecting different values for the tension command signal being at least in part constituted by the tension-control data outputs of the memory.
- 14. In a sewing machine as defined in claim 13, the means for automatically selecting different values for the tension command signal comprising means deriving the tension command signal from the data produced at the tension-control data outputs of the memory.
- 15. In a sewing machine as defined 14, furthermore including auxiliary user-operated selecting means operable by the user for altering the automatically selected values for the tension command signal when the user wishes to deviate from the automatically selected values.
- 16. In a sewing machine as defined in claim 15, the means deriving the tension command signal from the data produced at the tension-control data outputs of the memory comprising means for deriving an analog tension command signal, the auxiliary user-operated selecting means comprising a potentiometer receiving the analog tension command signal and having a user-adjusted wiper.
- 17. In a sewing machine of the type provided with a pattern memory consisting of addressable storage locations which store stitch-control data for at least one stitch-pattern, the pattern memory having stitch-control data outputs at which appear the stitch-control data contained in a memory storage location when that storage location is addressed, in combination, electromechanical thread-tension varying means operative for varying the tension of the thread fed to the sewing needle of the machine in response to a variable electrical tension command signal; and tension command signal generating means operative for furnishing to the electromechanical thread-tension varying means an electrical tension command signal, and including means for automatically selecting different values for the tension command signal, and thereby different values of thread tension produced by the thread-tension varying means, without the user of the machine needing to separately command said different values for the tension command signal, the means for automatically selecting different values for the tension command signal including means receiving the stitch-control data and deriving the tension command signal therefrom.
- 18. In a sewing machine as defined in claim 17, the means deriving the tension command signal from the stitch-control data comprising calculating circuit means operative for calculating appropriate values for the tension command signal dependent upon the stitch-control data.
- 19. In a sewing machine as defined in claim 18, the calculating circuit means comprising means operative for calculating from the stitch-control data distance-dependent values dependent upon the physical distances from one constituent needle-penetration location of a stitch-pattern to the next and producing the tension command signal in dependence upon the distance-dependent values.
- 20. In a sewing machine of the type provided with pattern selector means operated by the user for selecting differently configured stitch-patterns, in combination, electromechanical thread-tension varying means operative for varying the tension of the thread fed to the sewing needle of the machine in response to a variable electrical tension command signal; and tension command signal generating means operative for furnishing to the electromechanical thread-tension varying means an electrical tension command signal, and including means for automatically selecting different values for the tension command signal, and thereby different values of thread tension produced by the thread-tension varying means, without the user of the machine needing to separately command said different values for the tension command signal, the means for automatically selecting different values for the tension command signal comprising means furnishing a nominally-required-tension signal in dependence upon the selected pattern and indicating the thread tension nominally required, means furnishing cloth and thread signals dependent upon the thickness of the cloth to be sewn and dependent upon the thread to be employed, and means deriving the tension command signal from the nominally-required-tension signal and the cloth and thread signals.
CROSS-REFERENCE TO RELATED APPLICATION
The present application is a continuation-in-part of copending application Ser. No. 907,294 filed Mar. 6, 1978, now abandoned.
US Referenced Citations (4)
Foreign Referenced Citations (1)
Number |
Date |
Country |
45-18060 |
Jun 1970 |
JPX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
907294 |
Mar 1978 |
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