US3597672A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical drive systems for sewing machines
Assignee: Singer Co
•
Filing: 1968-12-30
•
Granted: 1971-08-03
•
Expires: 1988-12-30
Abstract
Abstract An electrical drive system for a sewing machine has a lowinertia DC motor drivingly coupled directly to the main shaft of the sewing machine. The motor is preferably of the type having a single low-inertia low-inductance armature immersed in a field of constant flux. A bridge rectifier using sequentially-fired drivecontrolled rectifiers supplies variable direct current to the armature from a commercial AC source. A fixed rectifier bridge supplies a reference voltage which is controlled by an operatoractuated controller to phase control the firing of the controlled rectifiers to provide running speed control. The armaturegenerated back E.M.F. is used automatically as a speed feedback signal opposed to the reference voltage to provide good speed regulation with respect to load variations. A separate stop controlled rectifier is rendered conductive responsive to a command initiated by the controller to provide dynamic braking of the motor for quickly stopping tee sewing machine.
Inventors
- 👤 Henry A Seesselberg
- 👤 Richard Beck
- 👤 Benjamin T Bernstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:19
CPC Classifications
D; D05; D05B; D05B69/00; D05B69/14; D05B69/18; H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/292; H02P7/293
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
134 words
An electrical drive system for a sewing machine having a shaft, said system being energizable from a commercial source of AC voltage comprising; a rotary armature immersed in a constant flux field and coupled continuously to said shaft, first controlled rectifier means providing a variable direct current supply only for said armature from said AC voltage source, second controlled rectifier means providing continuous dynamic braking of the armature, rectifier means providing a DC reference signal, and single adjustable means operative in a forward direction from a relaxed position for controlling the reference signal to selectively fire the first controlled rectifier means to control the acceleration of the sewing machine and operative in a reverse direction from the relaxed position to fire the second controlled rectifier means to control the deceleration of the sewing machine.
Claim 2
Dependent Claim
134 words
An electrical drive system for a sewing machine having a shaft, said system being energizable from a commercial source of AC voltage comprising; a rotary armature immersed in a constant flux field and coupled continuously to said shaft, first controlled rectifier means providing a variable direct current supply only for said armature from said AC voltage source, second controlled rectifier means providing continuous dynamic braking of the armature, rectifier means providing a DC reference signal, and single adjustable means operative in a forward direction from a relaxed position for controlling the reference signal to selectively fire the first controlled rectifier means to control the acceleration of the sewing machine and operative in a reverse direction from the relaxed position to fire the second controlled rectifier means to control the deceleration of the sewing machine.
Claim 3
Dependent Claim
125 words
An electrical drive system for a sewing machine energizable from a commercial source of polyphase AC voltage comprising; a DC motor having a high torque-to-inertia ratio, a rotary armature for said motor immersed in a constant flux field and continuously coupled to said sewing machine, a transformer connected to said voltage source and providing a polyphase AC voltage output of lower value than said source, first rectifier means providing a variable direct current supply only for said armature from said lower voltage output, second rectifier means providing continuous dynamic braking of the motor, and single adjustable means operative in opposite directions from a relaxed position for controlling respectively said first and second rectifier means to selectively control the acceleration and deceleration of said sewing machine.
Claim 4
Dependent Claim
125 words
An electrical drive system for a sewing machine energizable from a commercial source of polyphase AC voltage comprising; a DC motor having a high torque-to-inertia ratio, a rotary armature for said motor immersed in a constant flux field and continuously coupled to said sewing machine, a transformer connected to said voltage source and providing a polyphase AC voltage output of lower value than said source, first rectifier means providing a variable direct current supply only for said armature from said lower voltage output, second rectifier means providing continuous dynamic braking of the motor, and single adjustable means operative in opposite directions from a relaxed position for controlling respectively said first and second rectifier means to selectively control the acceleration and deceleration of said sewing machine.
Claim 5
Dependent Claim
163 words
An electrical drive system for a sewing machine energizable from a commercial source of polyphase AC voltage comprising; a DC motor, a rotary armature for said motor immersed in a constant flux field and continuously coupled to said sewing machine, circuit means providing a variable direct current supply only for said armature from said polyphase AC voltage source, adjustable means for controlling the variable direct current fed to the armature to set a predetermined speed for said sewing machine, means responsive to the angular speed of the armature for automatically controlling the armature current to maintain the predetermined speed constant with respect to load changes, further circuit means providing controlled continuous dynamic braking of said armature to control the deceleration of the sewing machine, and single actuated means operative in opposite directions from a relaxed position for conjointly controlling said adjustable means responsively to motion in one direction and the energization of said further circuit means responsively to motion in the opposite direction.
Claim 6
Dependent Claim
163 words
An electrical drive system for a sewing machine energizable from a commercial source of polyphase AC voltage comprising; a DC motor, a rotary armature for said motor immersed in a constant flux field and continuously coupled to said sewing machine, circuit means providing a variable direct current supply only for said armature from said polyphase AC voltage source, adjustable means for controlling the variable direct current fed to the armature to set a predetermined speed for said sewing machine, means responsive to the angular speed of the armature for automatically controlling the armature current to maintain the predetermined speed constant with respect to load changes, further circuit means providing controlled continuous dynamic braking of said armature to control the deceleration of the sewing machine, and single actuated means operative in opposite directions from a relaxed position for conjointly controlling said adjustable means responsively to motion in one direction and the energization of said further circuit means responsively to motion in the opposite direction.
Claim 7
Dependent Claim
44 words
An electrical drive system in accordance with claim 3, in which the variable direct current supply comprises a single separate controlled rectifier for each of the phases of the polyphase AC voltage including means for sequentially triggering the rectifiers to load each phase equally.
Claim 8
Dependent Claim
190 words
An electrical drive system for a sewIng machine energizable from a polyphase AC voltage source comprising; a DC motor having a low-inductance, low-inertia rotary armature immersed in a constant flux field and continuously coupled to the sewing machine, fixed rectifier means providing a constant DC reference signal, adjustable means for controlling the value of the reference signal, first controlled rectifier means for supplying variable direct current only to the armature, triggering means responsive to the adjustable means for sequentially firing said first controlled rectifier means in synchronism with the phase rotation of the polyphase AC voltage to supply driving torque to the sewing machine, means responsive to the rotational speed of the armature to modify the sequential firing to automatically maintain a constant sewing speed set by the adjustable means, second controlled rectifier means, means for triggering said second controlled rectifier means to energize a dynamic braking circuit only for the armature to provide a continuous braking torque to the sewing machine, and single control means operative in opposite directions from a relaxed position for controlling respectively the adjustable means and the means for triggering the second controlled rectifier means.
Claim 9
Dependent Claim
190 words
An electrical drive system for a sewIng machine energizable from a polyphase AC voltage source comprising; a DC motor having a low-inductance, low-inertia rotary armature immersed in a constant flux field and continuously coupled to the sewing machine, fixed rectifier means providing a constant DC reference signal, adjustable means for controlling the value of the reference signal, first controlled rectifier means for supplying variable direct current only to the armature, triggering means responsive to the adjustable means for sequentially firing said first controlled rectifier means in synchronism with the phase rotation of the polyphase AC voltage to supply driving torque to the sewing machine, means responsive to the rotational speed of the armature to modify the sequential firing to automatically maintain a constant sewing speed set by the adjustable means, second controlled rectifier means, means for triggering said second controlled rectifier means to energize a dynamic braking circuit only for the armature to provide a continuous braking torque to the sewing machine, and single control means operative in opposite directions from a relaxed position for controlling respectively the adjustable means and the means for triggering the second controlled rectifier means.
Claim 10
Dependent Claim
171 words
An electrical drive system for a sewing machine energizable from a source of AC voltage comprising; a DC motor having a low-inertia low-inductance rotary armature immersed in a constant flux field and continuously coupled to the sewing machine, first controlled rectifier means for supplying a variable direct current only to the armature from said polyphase voltage source, means including gated threshold diodes for supplying triggering pulses to said first controlled rectifier means in phase synchronism with the polyphase AC voltage in response to a start command signal, means responsive to the angular speed of the armature for automatically controlling the phase position of said triggering pulses to provide a constant speed, second controlled rectifier means for energizing continuously a dynamic braking circuit only for said armature, means for supplying a single triggering pulse to the second rectifier means in response to a stop command signal, and single means for alternatively establishing the start and stop command signals by positive movement thereof in respective forward and reverse directions from a relaxed position.
Claim 11
Dependent Claim
171 words
An electrical drive system for a sewing machine energizable from a source of AC voltage comprising; a DC motor having a low-inertia low-inductance rotary armature immersed in a constant flux field and continuously coupled to the sewing machine, first controlled rectifier means for supplying a variable direct current only to the armature from said polyphase voltage source, means including gated threshold diodes for supplying triggering pulses to said first controlled rectifier means in phase synchronism with the polyphase AC voltage in response to a start command signal, means responsive to the angular speed of the armature for automatically controlling the phase position of said triggering pulses to provide a constant speed, second controlled rectifier means for energizing continuously a dynamic braking circuit only for said armature, means for supplying a single triggering pulse to the second rectifier means in response to a stop command signal, and single means for alternatively establishing the start and stop command signals by positive movement thereof in respective forward and reverse directions from a relaxed position.
References Cited (Backward Citations)
US2970238A
Cited
US3189811A
Cited
US3149593A
Cited
US3195488A
Cited
US3268047A
Cited
US3295037A
Cited
US3494312A
Cited
US3374758A
Cited
US3319591A
Cited
US3463991A
Cited
US3458790A
Cited
US3501684A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-02 | 1975-02-01 | 1975-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-02 | 1979-02-01 | 1979-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-02 | 1983-02-01 | 1983-08-03 | $7700.00 | Window Closed / Lapsed |