JPS609776Y2 - Electromagnetic shutter sector drive device for photo cameras - Google Patents

Description

[Detailed Description of the Invention] The present invention has a cylindrical moving coil connected to a shutter sector and arranged to be movable in the longitudinal direction in an annular gap extending in the axial direction, and the annular gap is moved by a permanent magnet. The present invention relates to an electromagnetic shutter sector drive device for a photographic camera, such as an electromagnetic shutter sector drive device for a photographic lens shutter, through which a generated magnetic field penetrates.

The shutter sector is driven by a reciprocating ring that is connected to the shutter sector by a pin-slit connection, and this sector ring is connected to an armature that can be moved in the opening or closing direction by a system of electromagnets that can change the polarity. It is known to do so.

The purpose of the present invention is to operate with as small a moving part as possible in this type of electromagnetic drive device, to enable extremely high-speed shutter operation with little energy consumption, and to directly drive the waist 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, two pot-shaped casings are arranged at a distance such that the recessed portions of the pot-shaped casings face each other, and the annular gap has an outer peripheral contour defined by the pot-shaped casings. the inner peripheral contour is defined by a cylindrical permanent magnet core, the cylindrical permanent magnet core is disposed coaxially in the casing and is connected to the casing bottom at one end face, and the annular gap is defined by a casing opening. narrows over a predetermined axial length in the region of the permanent magnet core to a point close to the outer diameter of a moving coil provided on a support disposed coaxially with the permanent magnet core; The shutter sector, which moves linearly in the opposite direction from the one it supports, is held fixed.

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

As a result, the dimensions of the magnets can be made significantly shorter, the magnetic flux of the magnets being used more efficiently, so that only smaller magnets are needed to obtain a given drive force, which reduces the length of the magnetic drive mechanism. It has the advantage of being significantly smaller, allowing the magnetic drive mechanism to be small enough to be mounted directly on the objective lens for driving the central shutter.

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

The pot casings 1 and 2 are made of magnetic material or permanent magnets, and the insertion cores 3 and 4 are permanent magnets.

An annular gap 9, 10 is provided between the two on the cylindrical support 5, 6 for accommodating a moving coil 7.8, respectively.

The annular gaps 9, 10 are significantly narrowed at the pot casing inlet to form an overflow just to allow the passage of the moving coil 7.8.

As a result, an extremely strong magnetic field is formed in the narrow area, so
When the moving coil 7.8 is suitably energized, it is drawn into or withdrawn from the pot casing 1, 2 with a 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.

Shutter sectors 11 and 12 are respectively fixed to the sides of the coil supports 5 and 6 opposite to the movable coil attachment side.

In the illustrated embodiment, shutter sectors 11. '12 can be moved linearly perpendicular to the optical axis and is directly connected to the moving coil 7.8 which enters the pot casing 1,2.

In this embodiment, no mechanical coupling between the individual shutter sectors or moving coils is necessary, since the opening and closing of the shutter sectors takes place very quickly and exposure errors do not occur.

Due to the device of the invention and the constant driving force generated thereby, the movable body can be made very small, especially since the moving coil is extremely light, and since the shutter sector moves in a straight line perpendicular to the optical axis, it is relatively expensive. acceleration can be achieved.

Therefore, not only is the extremely short operating time of approximately 5/1 compared to a conventional electromagnetic shutter drive device, but this short operating time is also 0 minutes longer than that of a conventional general electromagnetic shutter drive device. It is distantly related to power consumption that is smaller than 1.

[Brief explanation of drawings]

The figure shows a partially sectional front view of a drive device according to the invention with two pot-shaped magnet systems. 1.2...Pot, 3,4...Iron core,
5, 6...Support, 7. Death... Moving coil, 9, 10... Annular gap, 11.12...
...Shutter sector.

Claims (1)

[Scope of utility model registration request] A cylindrical moving coil is connected to the shutter sector and is arranged to be movable in the longitudinal direction in an annular gap extending in the axial direction, so that the magnetic field generated by the permanent magnet passes through the annular gap. In an electromagnetic shutter sector drive device for a photographic camera, two pot-shaped casings 1 and 2
The annular gap is arranged at intervals such that the concave portions of the pot casings face each other, and the outer peripheral contour of the annular gap is defined by the pot-shaped casings 1 and 2, and the inner peripheral contour is defined by the cylindrical permanent magnet cores 3 and 4. The cylindrical permanent magnet core is arranged coaxially in the casing 1.2 and connected to the casing bottom at one end, the annular gap having a predetermined axial length in the region of the casing opening. The diameter of the moving coil 7.8 is narrowed to a point close to the outer diameter of the moving coil 7.8 provided on the supports 5, 6 which are arranged coaxially with the permanent magnet core.
An electromagnetic shutter sector drive device for a photographic camera, comprising fixedly holding a shutter sector 11.12 that moves linearly in a direction opposite to that supporting a movable coil 7.8.