Electronic controlling equipment for driving systems with electromagnetic couplings for industrial sewing and/or overcasting machines
First Claim
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1. A device for continuous speed control and control of presser foot lifting, thread loosening and thread cutting for an industrial sewing machine with electromagnetic coupling and a first shaft comprising:
- an operator input means for controlling said machine;
an asynchronous motor for driving said machine;
a clutch coupled to said asynchronous motor;
a transmission system;
a braking mechanism coupled to said clutch and coupled to said machine by said transmission system;
an inductive speed and position transducer coupled to said machine for detecting speed of said machine and position of said first shaft;
a comparator coupled to said speed and position transducer and said input means, for comparing said speed with a desired speed as established by said input means;
a logic block coupled to said input means, said machine and said speed and position transducer for controlling said presser foot lifting, said thread loosening and said thread cutting;
a speed regulator coupled to said comparator and said logic block for regulating said speed;
a first power amplifier coupled to said speed regulator and said clutch;
a second power amplifier coupled to said speed regulator and said braking mechanism; and
a voltage source coupled to said first power amplifier and said input means, said operator input means including a foot pedal,an elongated support having a longitudinally extending passage,a ferromagnetic rod displaceable in said passage parallel to a longitudinal axis of said support,a primary and a secondary coil surrounding said passage and offset along said axis, said primary coil being coupled to said voltage source, anda link coupling said ferromagnetic rod and said pedal,said speed and position transducer comprising;
a nonmagnetic second shaft coupled to said first shaft,a permanent magnet mounted on said second shaft and rotatable therewith, a stator being juxtaposed with said permanent magnet and having a coil with an output proportional to the speed of said first shaft, andan axially magnetized magnet carried by said second shaft and formed with ferromagnetic pieces flanking said axially magnetized magnet, a Hall-effect transducer extending between said pieces and having an output signaling the position of said first shaft,a housing having a longitudinally extending passage,a nonmagnetic second shaft rotatable in said passage, coupled to said first shaft and surrounded by a magnetic rotor armature, anda ring-shaped permanent magnet surrounding said second shaft, axially magnetized, having on a first side a first ferromagnetic piece and on a second side a second ferromagnetic piece, said first and second ferromagnetic pieces concentrating the flux of said ring-shaped magnet;
a rotoric inductive armature consisting of magnetic yokes being winded with a multiplicity of coils, whereby the electrical output of said coils is proportional to said speed of said first shaft; and
a magnetic sensor mounted in said housing parallel to said ring-shaped permanent magnetic for detecting the position of said first shaft.
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Abstract
The invention relates to an electronic system for the continuous speed control, with stopping at fixed preselected points for industrial sewing and/or overcasting machines. The invention also relates to a system which can afford additional control of the electromagnetic operational components e.g. the presser foot, of cutting device and of thread loosening device, using a driving system with an asynchronous motor and an electromagnetic coupling.
12 Citations
10 Claims
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1. A device for continuous speed control and control of presser foot lifting, thread loosening and thread cutting for an industrial sewing machine with electromagnetic coupling and a first shaft comprising:
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an operator input means for controlling said machine; an asynchronous motor for driving said machine; a clutch coupled to said asynchronous motor; a transmission system; a braking mechanism coupled to said clutch and coupled to said machine by said transmission system; an inductive speed and position transducer coupled to said machine for detecting speed of said machine and position of said first shaft; a comparator coupled to said speed and position transducer and said input means, for comparing said speed with a desired speed as established by said input means; a logic block coupled to said input means, said machine and said speed and position transducer for controlling said presser foot lifting, said thread loosening and said thread cutting; a speed regulator coupled to said comparator and said logic block for regulating said speed; a first power amplifier coupled to said speed regulator and said clutch; a second power amplifier coupled to said speed regulator and said braking mechanism; and a voltage source coupled to said first power amplifier and said input means, said operator input means including a foot pedal, an elongated support having a longitudinally extending passage, a ferromagnetic rod displaceable in said passage parallel to a longitudinal axis of said support, a primary and a secondary coil surrounding said passage and offset along said axis, said primary coil being coupled to said voltage source, and a link coupling said ferromagnetic rod and said pedal, said speed and position transducer comprising; a nonmagnetic second shaft coupled to said first shaft, a permanent magnet mounted on said second shaft and rotatable therewith, a stator being juxtaposed with said permanent magnet and having a coil with an output proportional to the speed of said first shaft, and an axially magnetized magnet carried by said second shaft and formed with ferromagnetic pieces flanking said axially magnetized magnet, a Hall-effect transducer extending between said pieces and having an output signaling the position of said first shaft, a housing having a longitudinally extending passage, a nonmagnetic second shaft rotatable in said passage, coupled to said first shaft and surrounded by a magnetic rotor armature, and a ring-shaped permanent magnet surrounding said second shaft, axially magnetized, having on a first side a first ferromagnetic piece and on a second side a second ferromagnetic piece, said first and second ferromagnetic pieces concentrating the flux of said ring-shaped magnet; a rotoric inductive armature consisting of magnetic yokes being winded with a multiplicity of coils, whereby the electrical output of said coils is proportional to said speed of said first shaft; and a magnetic sensor mounted in said housing parallel to said ring-shaped permanent magnetic for detecting the position of said first shaft. - View Dependent Claims (2, 3)
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4. Electronic equipment for continuous adjustment of speed, braking and stopping in a pre-set position and controls for presser foot lifting, thread loosening and thread cutting for a driving system having electromagnetic clutches for an industrial sewing and/or overcasting machine comprising:
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a contactless input device mechanically connected to the foot pedal controlling said sewing machine; an asynchronous electric motor driving said sewing machine; an electromagnetic clutch for coupling the shaft of said motor to the output shaft of said driving system; a second electromagnetic clutch for braking said output shaft; a transmission system located between the motor shaft and the shaft of said system; an inductive speed transducer and a position transducer having a magnetic sensor mounted on the machine shaft detecting the speed and the position of said machine shaft; a comparator having applied to one of its inputs the input value of said input device and to the other input the reaction value for the speed of said transducer; a control logic having as input value the output value of said input device and the reaction values of speed and position of said transducer, said transducer performing all controlled functions and interblocking constraints imposed by said sewing machine, said control logic cooperating with said input device so that front and back movement of said foot pedal controls the speed of said sewing machine, movement of said foot pedal into an intermediate back position automatically raises said presser foot, and further movement of said foot pedal into an extreme back position effects thread loosening and thread cutting; a speed regulator having as input values the error signal provided by said comparator and the logical signals given by said control logic in order to adjust the speed of said machine; a power amplifier having as an input value the signal given by said speed regulator, said amplifier controlling one of said electromagnetic clutches in order to apply a continually variable speed to said shaft of said machine; and a second power amplifier controlled by said logic by means of said speed regulator and operating another of said electromagnetic clutches in order to brake and position said shaft of said sewing machine. - View Dependent Claims (5, 6, 7, 8, 9, 10)
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Specification