The Singer Company

John A Herr

Wolfgang Jaffe

Jack Brown

Wesley R Peterson

John W Wurst

Donald J Coughenour

Oswald M Porter

Kenneth D Adams

Charles R Odermann

James A Transue

Philip F Minalga

Allan M Dob

William L Herron

Bruce R Rogan

Nicholas A Tarquinio

The back EMF generated in armature coils is substantially balanced by causing the coils located a greater distance from the axis of rotation of the armature to have fewer turns than the coils located closer to the armature axis of rotation. Alternatively, rather than decrease the number of turns in the coils, the same balancing affect can be achieved by increasing the electrical resistance of the coils located a greater distance from the armature axis of rotation.

Balanced armature winding for motors

A brush board assembly for a dynamoelectric machine is provided with flexible electrically conductive brush carrying flat springs which are pinned to a ring-like mounting board in a manner effective to electrically connect the spring to printed circuitry on the board.

Brush board assembly for dynamoelectric machine

A brush board for a dynamoelectric machine is formed with resilient arms which are an integral part of the board and have commutator engageable brushes affixed at the free ends thereof. The board carries printed circuitry which extends to the free end of the arms and connects with the brushes.

Brush board assembly for dynamoelectric machine with flat end commutator

A single air gap motor is provided with inner and outer coil wires in armature slots. Inner and outer coils with the same number of turns are symmetrically distributed around the armature and are connected in series with inner and outer coils alternating in the connection to balance out back E.M.F.

Multi-level armature winding for single air gap motor

A brushless direct current motor is provided with a rotor having a rare earth magnet within a nonferrous cylinder and a pair of coil windings which are air wound. To effect rotation of the rotor, current through the coils is controlled to rotate the resultant magnetic flux generated by the currents through the coils so that the rotor attempts to align itself magnetically with the resultant flux from the coils. Both coils are simultaneously energized and the polarity of current flow through the coils is reversed in such a manner that there is a current reversal through only one of the coils whenever the current is switched. Coil switching is directed by a triggering magnet fixed on the rotor shaft, which magnet operates Hall effect switches. The Hall effect switches in turn operate power switches to apply the correct voltage and polarity simultaneously to both windings.

Brushless direct current motor and control therefor

A tension device for sewing machines is disclosed having thread tensioning discs and a linear actuator for applying a compressive force between the discs. The invention is characterized in that for any given tension setting of the device, the applied compressive force, or tension, remains constant regardless of any variations in the spacing of the discs due to variations in the thread thickness, up to the range of travel of the linear actuator.

Electro-magnetic thread tension control for sewing machines

A Hall effect switch device converted to a latching relay by having a reversible bias magnet attached thereto adjacent the Hall sensor so as to operate the switch circuit in one polarity of the bias magnet, and release the switch circuit in the other polarity of the bias magnet.

Latching relay using Hall effect device

A single air gap permanent magnet electric motor is provided with field magnets formed as thick annular segments concentric with the axis of rotation of a solid non-magnetic cylindrical armature. The field magnets are magnetized radially to the axis and have oppositely polarized pole faces facing the axis. The ratio of the thickness to the inner diameter of the annular segments is maintained within a defined range to provide for a high magnetic flux density across the single air gap.

Annular segment permanent magnet single air gap electric motor

An electric motor, such as a rare-earth permanent magnet single airgap direct current motor is provided with generally longitudinally extensive heat transfer or cooling means comprising heat receptor elements adjacent but minimally spaced apart from and parallel the armature. These heat transfer elements are then cooled, as by being thermally connected with external heat discharging or dissipating structure to transfer the heat away from the motor. In one embodiment or modification the heat transfer elements project inwardly from a heat conductive end cap provided on its outer surface with heat radiating fins. In another embodiment or modification the heat transfer elements are hollow and a coolant, such as air, is circulated therethrough. The heat receptor elements may be provided with fins to increase their surface area, with the fins preferably facing the armature structure. The receptor elements are also preferably substantially coextensive with the active portion or windings of the armature. A stirring fan may also be provided mounted to the armature to provide circulation of air within the motor housing, around the armature and heat transfer elements.

Method of and apparatus for cooling electric motors and totally enclosed

A sewing machine, wherein a stitch controlling instrumentality is positioned during operation of the machine by a motor acting through connecting linkages, is provided with a ring magnet that is connected to said linkages for angular displacement thereby about its axis and with a linear output Hall effect sensor that is disposed within the ring magnet to produce an output voltage proportional to displacement of the stitch forming instrumentality.

Position sensing device for electronic sewing machine

A pump is disclosed having a housing with a recess therein, an elastomeric diaphragm stretched across said recess forming a pump cavity in which the medium being pumped is circulated, and inlet and outlet valves. An electronically controlled linear actuator is attached to the diaphragm within the pump cavity thereby allowing compactness in the construction of the pump and improved heat dissipation from the linear actuator. The pump fits within the frame of a sewing machine and creates an air vacuum for assisting in needle threading.

Diaphragm pump for needle threading

A fixed speed sewing machine is disclosed having only start and stop control capability for the actual running of the machine. An arrangement is provided for controlling the acceleration of the sewing machine drive motor so that it is gradual, rather than abrupt.

Ramp speed integrated motor controller for sewing machines

A pump for needle threading is disclosed having a housing with a recess therein, an elastomeric diaphragm stretched across said recess forming a pump cavity in which the medium being pumped is circulated, and inlet and outlet valves. An electronically controlled linear actuator is attached to the diaphragm within the pump cavity thereby allowing compactness in the construction of the pump and improved heat dissipation from the linear actuator.

A circuit which limits the maximum permissible speed of a sewing machine motor when specific stitch patterns are selected. Electronic signals from a means for sensing the selected stitch pattern are analyzed by the circuit to control the operation of a relay which connects a resistance in series with the sewing machine motor to reduce the maximum speed at which the drive motor may be operated.

Sewing machine motor speed limiting by pattern selection

A mechanism for detecting the depletion of bobbin thread in a sewing machine. A bobbin is formed with a polygonal core having a plurality of light reflecting surfaces contained thereon. A light source transmits a beam of light toward the polygonal core of the bobbin and the light reflected therefrom is intercepted by a photodetector. The polygonal reflecting surfaces contained on the bobbin core do not begin to reflect light until a sufficient quantity of bobbin thread has been consumed in the sewing process to expose a part of the reflective surface portion of the bobbin core. The rotation of the bobbin thereafter results in flashes of light being received by the photodetector. An electronic circuit analyzes the output of the photodetector and distinguishes between the flashes and steady ambient light to signal the impending depletion of bobbin thread.

Growing community of inventors

Garwood, NJ, United States of America

John A Herr