Abstract: A position detecting device such as a needle position detecting device which detects a needle position with the aid of a rotor. In the position detecting device, the rotor and a position detecting annular member are abutted against each other, and thus the use of screws can be eliminated, and the annular member can be readily adjusted in angular position with a tool which is inserted through the holes of the rotor and engaged with the adjusting means of the annular member.

Abstract: A flywheel device in which a rotating body is rotatably supported within a casing, the rotating body comprising a rotor rotated at a high speed and a flywheel rotated integrally with the rotor to accumulate rotating energies capable of being converted into electric energies at a time of a power failure. A protective ring is provided beween the outer surface of the rotating body and the inner circumferential wall of the casing. Upon the occurrence of an abnormally high speed of the rotating body, the rotor of the rotating body engages the protective ring. The protective ring is free of fixed engagement with the casing so that when engaged by the rotor the weight of the protective ring is added to that of the rotating body to act as a braking force.

Abstract: A sewing machine controller in which initially a rotation transfer ratio is calculated from the number of rotations of a motor and the detected number of rotations of the sewing machine shaft. Thereafter, the number of motor rotations is calculated as the product of the rotation transfer ratio and the desired number of rotations of the sewing machine.

Abstract: An improved lever mechanism interlocked with a pedal in a sewing machine driving device, which lever mechanism includes a rod positioned on one side portion of a lever so as to act on the lever when the latter is pivoted in one direction from a neutral position, and first and second springs of different diameters disposed concentrically with the above rod so as to urge the rod in the direction opposite to the pivoting direction of the lever.

Abstract: A low inertia, speed variable induction motor comprises a frame, a stator fixedly placed in the frame, a yoke fixedly placed in the frame in opposition to the stator with a predetermined gap and a cup-shaped rotor which is inserted into the gap and is fixedly mounted on an output shaft supported in the frame in a freely rotatable manner. Rotating magnetic field is produced in the gap by the stator and the yoke to generate a rotational torque of the cup-shaped rotor. The cup-shaped rotor is formed of a material or materials having a hysteresis characteristic and an eddy current producing characteristic to obtain a large torque.

Abstract: The disclosure describes an electromagnetic clutch/brake device which prevents undesired vibration of a rotary brake mounted on an ouput shaft so as to be slidable in its axial direction. For this purpose, the rotary brake is made unbalanced in weight in a specified direction with respect to its revolution center and a driven rotary body mounted on the output shaft and subjected to rotational force from the output shaft is made unbalanced in weight in a specified direction with respect to its revolution center. The driven rotary body and the rotary brake are fitted to the output shaft so that they are in a balanced condition when the shaft is driven.

Abstract: A low inertia, speed variable induction motor with a stator, a yoke, and a rotor mounted on an output shaft being accommodated in the interior of a frame, wherein the stator is fixedly provided inside the frame, the yoke is rotatably mounted inside the frame in a manner to oppose the stator with a small gap between them, and a cup-shaped rotor is inserted into the small gap between the yoke and the stator, thereby reducing the size and weight of the driving body including the cup-shaped rotor, and improving its high speed response property.

Abstract: A movable disc for a friction type electromagnetic clutch/brake is designed for preventing the production of grating sounds from the movable disc. The movable disc includes a rotary armature being movable in a predetermined direction by the application of electromagnetic force, a friction material stuck onto one side surface of the rotary armature, an elastic member supported on one side surface of the rotary armature to the side opposite to the friction material, a face plate fitted to the rotary armature so as to urge the elastic member to the rotary armature. Perforations are formed in the face plate to reduce its mass and the surface area contacting to the elastic member thereby attaining a rapid start up and good periodic damping characteristic.

Abstract: A low inertia induction motor to increase to speed responding characteristic at the time of its start and stop comprises a stator core fixed inside a frame, a yoke disposed in confrontation to the stator core with a space gap and a rotor interposed within the space gap between the yoke and the stator core. A through-hole is formed at the center portion of the frame for supporting the yoke or the stator core, a rotationary shaft is rotatably inserted into the through-hole and the rotational shaft is attached with a rotational plate for supporting the rotor and a cooling fan for feeding cooling air in the interior of the frame.

Abstract: A motor has an electromagnetic brake which is connected to the output shaft to brake the rotation of the output shaft, whereby the driving body can be forcibly braked with excellent stopping response.A fan for forcibly cooling the inside of the motor is enclosed in the casing, whereby temperature rises can be prevented by ventilation.A bracket for supporting the iron core of the brake coil is made of a non-magnetic material, whereby the leaked magnetic flux passing through the bearing fixed on the bracket can be prevented, and consequent damage to the bearing heated by the eddy current can be prevented.The stator can be a stator having windings used in a conventional induction motor, and the rotor is a cup type rotor having a simple structure extended in the axial direction. Accordingly, the structure is simple, and the size of the motor in the radial direction can be reduced.

Abstract: An electromagnetic coupling device including a drive member coupled to the rotary shaft of an electric morot and a follower operating in response to the drive member. The drive member includes first and second magnet pole pieces and a magnetic path forming member. The drive member having a relatively large inertia, serves also as a flywheel. The follower is made to have a relatively small inertia to improve its response characteristic. The drive member has a space incorporating a fixed exciting coil and a fixed magnetic path forming member and a clearance accomodating eddy current generating plate thereby reducing the overall axial dimension of the electromagnetic coupling device.