Abstract: An electronically-operable door strike employing a guard clip for deterring picking of the locking mechanism therein, a springless solenoid designed to avoid the undesirable build-up of residual magnetism and which incorporates air gaps for dissipating heat, thus prolonging the useful life of the solenoid, and a face plate for mounting the strike into a door jamb.

Abstract: An electronically-operable door strike employing a guard clip for deterring picking of the locking mechanism therein, a springless solenoid designed to avoid the undesirable build-up of residual magnetism and which incorporates air gaps for dissipating heat, thus prolonging the useful life of the solenoid, and a face plate for mounting the strike into a door jamb.

Abstract: An electrically operable strike with a pivotable keeper and a rectilinearly slidable locking member with planar major surfaces with arms extending parallel to the surface planes, which arms in one position of the locking member prevent pivoting of the keeper and which in a second, different position of the locking member, permit the keeper to pivot. The locking member has a magnetic portion and is moved from one position to the other by the magnetic field of an electrically energizable coil having its axis perpendicular to the plane of movement of the locking member. There are two similar locking members, and with one locking member, the strike is normally locked and by replacing such locking member by the other locking member, the strike is normally unlocked. In one embodiment, the keeper engages faces of the locking member arms and in another embodiment, the keeper engages faces at the ends of the locking member arms.

Abstract: 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.

Abstract: A dynamoelectric machine having a stator of permanent magnet segments, each segment being formed of a plurality of laminae concentrically oriented with respect to the armature, wherein an outer laminae exhibits demagnetization characteristics effective to prevent substantial permanent loss of magnetism in an inner laminae.

Abstract: 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.

Abstract: 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.

Abstract: A Hall effect sensor is disposed between two magnets having their fields in quadrature and in association with a movable specially formed ferromagnetic part which is used to control flux in the sensor in such a way as to cause the sensor to produce a linearly varying output voltage dependent upon the position of the part.

Abstract: 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.

Abstract: 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.

Abstract: A linear motor is provided with a coil, a plunger selectively positionable thereby, a permanent magnet concentric with the coil and plunger having oppositely polarized magnetic poles on outer and inner surfaces creating a magnetic circuit extending through the plunger, end caps of non-magnetizable material in line with the plunger, and an output shaft of non-magnetizable material extending through an end cap.

Abstract: A linear motor construction in which a plurality of parallelpiped shaped permanent magnets are retained within an easily molded spool having an axial bore formed through the axis thereof. A coil which may be electrically excited is wound about the spool and produces a magnetic field when excited, which reacts with the field produced by the permanent magnets to cause linear motion in a ferro-magnetic, cylindrical armature which is slidably contained within the axial bore.

Abstract: 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.

Abstract: When it is not possible to place magnets into their final assembly before magnetizing them, the performance of high energy magnetic materials having a nonlinear demagnetization characteristic at room temperature is improved by heating the magnetic material, magnetizing the heated magnetic material and then placing the resulting heated magnetic into its final assembly and letting it cool to room temperature.

Abstract: 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.

Abstract: 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.

Abstract: A low bobbin thread supply alarm in which a bobbin case is fitted with lever pivoted thereon and carrying a permanent magnet for travel to the hub of the bobbin. An arm overhanging the bobbin case and bobbin carries a Hall generator in a portion thereof overlying the hub of the bobbin. The lever and permanent magnet carried thereby is urged by an electromagnet supported externally of the looptaker toward and away from the hub of the bobbin at suitable intervals. When the lever pivots greater than a given amount due to depletion of thread on the hub of the bobbin the permanent magnet on the lever will trigger a voltage change on the Hall generator which may cause an appropriate alarm to provide a warning of a low thread condition.

Abstract: 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.

Abstract: This disclosure relates to electric motor/actuators and in particular to an electric motor/actuator for driving a sewing machine and operating sewing machine controls regulating, for instance, the position coordinates of the resulting stitches formed by the sewing machine. The electric motor includes multiple non-magnetic armatures having commutated windings rotatable in a single air gap formed between opposing permanent magnets having their opposed polarized poles facing said armatures and wherein individual ones of said armatures are capable of different output functions free of significant interaction with others of said armatures.

Abstract: A position sensing device is disclosed including an assembly of a Hall effect generator element shiftably supported relatively to a permanently magnetizable element. Each such Hall effect generator element being randomly chosen from an inventory of parts having wide tolerance limits of Hall effect output under like magnetic flux influence; and each magnetizable element from an inventory having a widely varying magnetic capability after exposure to like magnetizing influence. The magnetization of the magnetizable element of each such assembly being imparted thereto under control of the Hall effect output of the specific Hall effect generator in the assembly with the result that every position sensing device so assembled can be made to produce substantially identical Hall effect output in each relative position of said elements.