Abstract: An optical scanner or actuator comprising an armature which includes a movable, closed electrically conductive loop, the armature being mounted to rotate about a support axis, current inducing means associated with the electrically conductive loop comprising a stationary flux-conductor extending through and in current-inducing relationship with the loop, and drive means adapted to induce a magnetic current-inducing flux along the flux-conductor in accordance with desired movement of the armature, permanent magnet biasing means comprising a permanent magnet adapted to produce a magnetic field with which current in the electrically conductive loop interacts to cause movement of the armature, one pole of the magnet being permeably connected to one portion of the flux-conductor at a region remote from the electrically conductive loop, and the other pole of the magnet being permeably connected with the flux-conductor via a permeable gap in which a segment of the electrically conductive loop is arranged to move, wh

Abstract: A limited-rotation actuator in which the rotor pole faces and corresponding stator pole faces are spaced apart along the axis of rotation, the rotor pole faces are permeably connected by a flux path having an axial component through the rotor, and the rotor and stator pole faces each subtend an angle of between about 90.degree. and about 180.degree. around the axis. The invention enables wide angle excursions of the rotor and inexpensive fabrication.

Abstract: The invention relates to a limited rotation galvanometer having a shaft adapted to be deflected in accordance with an electrical drive signal applied to the galvanometer, the galvanometer comprising a stator assembly formed of at least one stationary permanent magnet and at least one pole piece cooperatively arranged about a hollow bore, a rotor associated with the shaft and mounted to turn in the hollow bore, and an electrical winding wound about the pole piece and adapted to receive the drive signal, this stator assembly and rotor defining magnetic circuitry for operation of the galvanometer, the deflection of the rotor being dependent upon the rigidity of the stator assembly and the value of the torque applied between the stator assembly the rotor by the application of the drive signal to the winding.

Abstract: A subfractional horsepower, permanent magnet motor has a stator assembly with a pair of axially aligned stator coils in stacked relation, and complementary metal housing members that enclose the coils and define a series of stator poles. An elongated sleeve disposed within the annular stator assembly provides, with the metal housing members, magnetic circuits that surround the stator coils. The stator sleeve is disposed over and interfitted with a frame core that has significantly greater thermal conductivity than the thermal conductivity of the stator sleeve. A channel extends from at least one of the stator coils along the axial length of the core to the base, and the leads of that coil extend radially inward from the coil and along the channel to the base and therefrom externally of the motor.

Abstract: A strip chart recorder having cantilevered spring arms integrally molded with its rigid chassis. One set of spring arms maintains pressure on a paper drive nip, another set permits resilient deflection of a rod to latch a paper supporting door, and a third set resiliently retains the paper supply roll. Improved drive is obtained by movable mounting of the drive roll in a special relationship that causes it to react to resistance of the paper by tightening the drive nip pressure.

Abstract: A device for providing a voltage indicating the angular velocity of rotation of the armature in a limited rotation, polarized, moving iron galvanometer. The device includes a means for providing a first voltage dependent upon the angular velocity of the armature, the self-inductance of the galvanometer drive coil, and the drive current in the drive coil. A compensation coil is magnetically coupled to the drive coil and magnetically isolated from the effects of the rotating armature to provide a second voltage which is dependent upon mutual inductance between the drive and compensation coils and upon the drive current, but is not dependent upon the effects of the rotating armature due to the magnetic isolation of the compensation coil from the armature. A combining means proportionally combines the first and second voltages to provide a voltage indicating the angular velocity of rotation of the armature.

Abstract: A subfractional horsepower permanent magnet synchronous motor comprises an annular stator and a cup-form permanent magnet rotor defining an internal cylindrical volume. The rotor is supported for rotation within the stator about the axis of the motor and with an annular air gap between the stator and the cup-form rotor, and means including a stator coil is adapted to be energized to rotate the rotor relative to the stator. An output shaft coaxial with the rotor extends outwardly from one end of the stator, and a stationary support bushing for the output shaft extends into the internal volume defined by the rotor. A gear train is mounted in the space between the inward end of the support bushing and the closed end of the cup-form rotor, and is coupled between the rotor and the output shaft to provide a predetermined speed reduction ratio between the rotor and the output shaft.

Abstract: A transformerless capacitance detection device for picofarad level capacitances, used in a galvanometer for position feedback. A variable capacitor is connected between transistor emitter and ground with a ground-referenced oscillating voltage source connected directly to base and a capacitor discharge means connected to the emitter. Oscillating voltage appears across the capacitor via the transistor base; the capacitor is charged through the transistor while the transistor is conducting and is discharged through the discharge means while the transistor is non-conducting. The collector current while conducting is a measure of capacitance in this transformerless, simple circuit. This current is used to feedback the position of the rotor of a galvanometer or other moving element to enable operation of the position control circuit for the element.

Abstract: A limited rotation motor has a stator and a rotor mounted for limited rotation relative to the stator. The stator is constructed to conduct bias flux through magnetic circuits that extend across air gaps between the stator and the rotor and a drive system produces drive flux which is conducted through magnetic circuits that extend across air gaps between the stator and rotor to drive the rotor. The stability of radial rotor position in its support bearings is enhanced by an imbalance in the bias flux magnetic circuits which continually produces a resultant radial force on the rotor so that a well defined radial position of the rotor is maintained over the range of limited rotation that the rotor moves in response to the drive system.

Abstract: An electrically damped oscillation motor having a stator component, a rotor component, a permanent magnet which provides a magnetic field across the annular gap transverse to the axis of rotation of the rotor and a drive winding for passing an electric current that interacts with the magnetic field to produce rotational deflection of the rotor. Both a tachometer winding and a compensation winding are provided in fixed relation to the drive winding, the compensation winding being located at a greater radial distance from the annular gap than the tachometer winding, and the tachometer and compensation windings being connected together in circuit so that the signal induced in the tachometer winding due to electric current flow in the drive winding is cancelled by a similar signal induced in the compensation winding, while the tachometer and compensation windings provide a net velocity signal that is used to modify the electric current flow in the drive winding to electrically damp rotational motion of the rotor.

Abstract: A bearing free oscillation motor has a stator component that defines a cylindrical cavity and a rotor component with a cylindrical portion disposed within the cavity and spaced from the cavity wall by an annular gap of radial width in the range of one-five percent of the diameter of the cylindrical portion. The rotor is supported for rotation about its axis by attachment to one end of a torsion shaft that is fixed at its other end to the stator. The motor may be of either the moving coil or the moving magnet type, that is a permanent magnet provides a magnetic field across the annular gap and electric current flow through a drive winding interacts with the magnetic field to produce a torque that rotationally deflects the rotor. Disposed in the annular gap between the stator and rotor is a low viscosity liquid that produces essentially no viscous damping, for example a hydrocarbon oil, a silicone oil or a polymeric liquid.

Abstract: Moving iron limited rotation motors, and recorders employing such motors, in which a velocity sensor structure is axially spaced from a drive structure that is shorter than another drive structure of the drive system. In the preferred embodiment shown, a motor having a pair of diametrically opposite drive structures, the sensor is positioned opposite to the end of the longer drive structure and cooperates with it and a coextensive portion of the rotor in defining flux paths. A pair of permanent magnets extend the full length of the drive-sensor structure, supplying flux to both parts.

Abstract: According to one feature a bearing-free oscillation motor, e.g. for driving an optical scanner or chopper comprises a torsion shaft fixed at one end for rotational oscillation about its axis, a rotor support member substantially more rigid in bending than the torsion shaft attached to the free end of the shaft and extending back therealong, a magnetically interactive rotor rigidly joined to the support member at the midlength of the torsion shaft, and a magnetically interactive stator adjacent the rotor for inducing rotational oscillation of the rotor, the torsion shaft and the rotor support member cooperating to provide a stiff system in bending. Preferably the rotor torsion shaft and rotor support member assembly are cooperatively constructed to restrain the rotor, in response to radial forces acting on it, to substantially translational motion without tilting of the rotor or the attached mirror or other device.

Abstract: An alarm system includes a floating transmitter which when activated by a wave will generate one short signal and then turn itself off. A radio receiver will detect and verify the time duration of the radio signal, and thereupon activate an audible alarm. The alarm will continue to sound until it is manually turned off.