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Electronic controlling equipment for driving systems with electromagnetic couplings for industrial sewing and/or overcasting machines

  • US 4,658,742 A
  • Filed: 09/24/1984
  • Issued: 04/21/1987
  • Est. Priority Date: 01/24/1983
  • Status: Expired due to Fees
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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