JPS609774Y2 - Electromagnetic shutter sector drive device for photo cameras - Google Patents

Description

[Detailed description of the invention] The invention has a curved cylindrical coil connected to a shutter sector and disposed so as to be longitudinally movable in an annular gap;
The present invention relates to an electromagnetic shutter sector drive device for a photographic camera in which a magnetic field generated by a permanent magnet passes through the annular gap.

The shutter sector is driven by a reciprocating ring connected to the shutter sector by a pin-slit connection,
It is known to connect this sector ring with an armature which can be shifted from the opening direction to the closing direction by means of an electromagnetic system whose polarity can be changed.

The purpose of the present invention is to operate this type of electromagnetic drive device with as small a moving part as possible, to enable extremely high-speed shutter operation with little energy consumption, and to directly drive the shutter sector without using an intermediate transmission member. The aim is to create something that is suitable for use and therefore operates with particularly high efficiency.

As a distant relative of this purpose, according to the present invention, the annular gap is defined by a pot-shaped casing whose outer circumferential contour is curved into an arc, and whose inner circumferential contour is shaped like a rod disposed coaxially within the pot-shaped casing 1. defined by a permanent magnet, the rod-shaped permanent magnet being connected at its end face to the casing bottom, the annular gap being close to the outer diameter of the curved cylindrical coil over a predetermined axial length in the region of the casing opening. The shutter sector, which rotates around a rotation point, is directly fixed to the curved cylindrical support body which is narrowed to a certain extent to form a narrow part and supports the curved cylindrical coil.

According to the present invention, by narrowing the annular gap, all lines of magnetic force are concentrated in the narrow portion, and all the magnetic force obtained thereby can be effectively utilized.

At any position of the coil displacement, the generated magnetic flux that concentrates on the same number of coil turns always penetrates, so the constant speed of the coil is distantly related, and in this case, the coil displacement range does not remain in the area surrounded by the magnet. Good too.

In addition, the curved configuration of the magnets and the direct fixation of the shutter sector, which pivots around a point of rotation, on the coil support make it possible to achieve significantly shorter dimensions, in which case the magnetic flux of the magnets is used sufficiently effectively, so that , a smaller magnet is required to provide the driving force, which significantly reduces the length of the magnetic drive so that it can be attached directly to the objective lens for driving the central shutter. It has the advantage of being small.

Embodiments of the present invention will be described in detail below with reference to the drawings.

The pot-shaped casing 1 curved into an arc is made of a permanent magnet, and the insertion core 2 coaxially fixed therein is a permanent magnet.

An annular gap 3 is provided between the two for accommodating a moving coil 4 supported by a curved cylindrical support 5.

The annular gap 3 narrows significantly at the inlet 5 to form a narrowing 6 just to allow the passage of a moving coil 4 carried on a support.

As a result, a significantly stronger magnetic field is created in the narrow part 6, so that the moving coil 4, when suitably energized, is drawn into or out of the pot 1 with an approximately constant force over its entire length.

As a result, this electromagnetic drive is particularly suitable in cases where a constant force is required over a distance.

By reversing the polarity of the windings of the moving coil 4, the device can be used in both directions with the same effect.

Furthermore, each shutter sector 7 is directly fixedly connected to the support 5 of its own moving coil 4 .

In this case, the moving coil 4 and the pot-shaped magnet casing 1
is bent into a circle around the rotation point 8 of the sector 7.

The device according to the invention and the constant driving force generated by it enable relatively high accelerations to be achieved, especially since the moving coil is very light and the moving body can be made very small.

Therefore, not only is the operating time very short, about one-fifth of that of a conventional electromagnetic shutter drive, this short operating time is also much shorter than that of a conventional electromagnetic shutter drive. It is distantly related to one or more of the following with moderate power consumption.

[Brief explanation of drawings]

The figure is a partially cutaway front view of the electromagnetic shutter drive device of the present invention. DESCRIPTION OF SYMBOLS 1... Pot-shaped casing, 2... Permanent magnet, 3... Annular gap, 4... Moving coil, 5... Support body , 6...Narrow area, 7...Glossy sector, 8...Rotation point.

Claims (1)

[Scope of utility model registration request] An electromagnetic shutter for a photographic camera having a curved cylindrical coil connected to a shutter sector and disposed so as to be longitudinally movable in an annular gap, the annular gap being penetrated by a magnetic field generated by a permanent magnet. In the sector drive device, the annular gap 3 is defined by a pot-shaped casing 1 whose outer peripheral contour is curved into an arc, and whose inner peripheral contour is defined by a rod-shaped permanent magnet 2 coaxially arranged inside the pot-shaped casing 1. The rod-shaped permanent magnet is connected at its end face to the casing bottom, and the annular gap 3 is close to the outer diameter of a cylindrical coil 4 which is curved over a predetermined axial length in the region of the casing opening. An electromagnetic camera for a photographic camera, in which a shutter sector 7 rotating around a rotation point 8 is directly fixed to a curved cylindrical support 5 which supports the cylindrical coil and is narrowed to form a narrow part 6. type shutter sector drive device.