A core magnet type instrument which renders a linear response characteristic comprises a magnet core, a yoke surrounding and spaced apart from the magnet core to form an air gap therebetween, and a moving coil movable in the air gap and having a pointer. The magnet core is shaped into an ellipse to improve a response characteristic of the instrument.

A magnetic head comprises a magnetic record or magnetic record-reproduce head core for forming a magnetized track, and an erase head core secured to the magnetic record-reproduce head core for forming erased tracks along the upper and lower marginal edges of the recorded track formed by the magnetic record or record-reproduce head core. The magnetic record or magnetic record-reproduce head core has at least one effective gap. The erase head core has its erase head gaps formed by the outer edges ...

DC motor and control system therefor utilizing Hall generators are disclosed. A stator has a pair of flux-producing windings positioned in torque-producing relation with a rotor having magnetic poles of opposite polarities. A pair of Hall generators are positioned in flux-sensing relation with the poles on the rotor, and driving means for applying the currents to the stator windings is connected to a switching or commutation circuit which is actuated in response to the output signal from a contr...

A control system is disclosed for driving a DC commutator motor or brushless motor in precise synchronism with the external reference signal. A gate circuit which gives the logic output of the reference signal and the frequency signal representative of the rotational speed of the DC motor, generates ths signal for permitting the power supply to the DC motor in response to the first reference signal even when the reference and frequency signals are not alternately applied to the gate circuit, and...

A method and device used with an electronic photocopying apparatus and for removing any residual developing solution from a photosensitive member by the use of a corona discharger to thereby provide a perfect copy of an original image.

An input signal generating device for computers comprises a plurality of keys arranged on the keyboard each of which keys has means responsive to the depression of the associated key for magnetically producing an input signal to operate the operation unit. The means for producing the input signal comprise a coil and a magnetic member one of which is responsive to the depression of the associated key. The relative movement of the magnetic member and the coil induces voltage across the coil as an ...

This specification discloses a positioning device for setting an article in a predetermined position. The article to be positioned by the device has a referential pattern of predetermined shape formed on a surface thereof. The positioning device comprises reference pattern carrier means having a reference pattern whose base portion is substantially similar in shape to the referential pattern of the article. Means is provided to move the article in a plane and to a position where the referential ...

A film rewind device is characterized by a plural number of rollers which are made to contact, under pressure, a portion of the end of a spool within a cartridge which end projects out of the end plate of the cartridge, and at least one of the rollers is linked with a lever for rewinding the film

A camera provided with a recording device for a photographed date, comprising an auxiliary optical lens system common to day, month and year for making an image of a date onto film overlapping on a part of a picture from an outer object, three rings for date preselection, a middle one of said rings being supported coaxially and slidably arround an inner one of said rings and supporting a remaining outer one of said rings coaxially and slidably around said middle one of said rings, each of said r...

An magnetic recording apparatus comprises a magnetic tape and an endless magnetic recording medium. The former carries information signals such as auditory teaching materials recorded upon the first track at a predetermined interval and control signals recorded upon the second track. In reproducing the information signals, they are reprinted or transferred upon the endless magnetic recording medium which has the length substantially equal to the length of the information signal record plus the l...