JPS5810732B2 - Photographer shutter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shutter device for a camera.

Generally, when adjusting the exposure amount of film in response to external conditions, a camera adjusts the shutter speed and/or the aperture of the exposure hole, or the aperture. The high-speed shutter drive mechanism must be controlled with high precision, so
This is more difficult than adjusting the aperture.

Therefore, in order to provide a camera at a low cost, it is advantageous to keep the shutter speed constant and to be able to adjust only the aperture.

However, even with a constant speed shutter device, the shutter is still driven at high speed. Those that drive shutter blades or shutter membranes such as cloth have the drawbacks of complex structures, high prices, and large operating noises. Even in the case of a method that drives the shutter blades, the shutter blades must be moved at high speed in the opening direction and then immediately moved at high speed in the closing direction, and the drive is reciprocating, making assembly complicated and requiring high precision. Moreover, when a solenoid is used, it also has disadvantages such as increased weight.

The present invention was made in view of this point, and uses the attractive force and repulsive force of a permanent magnet to rotate a shutter plate with one hole for the shutter, and has a simple structure, light weight, and low cost. To provide a constant speed shutter device that can be manufactured and has low operating noise.

A single embodiment of the present invention will be described based on the drawings.

A board 1 is provided on the front of a camera (not shown), and this board 1
A lens hole 2 is opened in the lens hole 2, and a disk-shaped magnet 3 having a magnetic pole on a flat surface is placed around a screw hole formed horizontally close to the lens hole 2. , S, N, S, even numbers, for example, 6, are arranged in sequence.

A magnet 5 having the same shape as the magnets 3 arranged on the substrate 1 is placed around an opening formed in the center of a disc-shaped shutter plate 4 made of a light-shielding material different from the substrate 1.
Only half of the number, that is, three, are arranged at equal angles with the same magnetic poles facing at intervals.

Further, a radius is set around the shutter plate 40 from the central opening to the distance between the lens hole 2 of the substrate 1 and the screw hole of the substrate 1, and when the magnets 3 and 5 of different polarities are attracted and come into close contact with each other, the lens hole 2 A plurality of shutter holes 6 are opened at positions that do not overlap.

The shutter holes 6 are opened at three equal angles corresponding to the number of magnets provided on the shutter plate 4.

At the same time, the same number of actuating pieces 7 as shutter holes 6 are provided protruding from the outer periphery of the shutter plate 4 at equal angles.

The shutter plate 4 is rotatably attached by inserting the screw 8 passing through the opening of the shutter plate 4 into the screw hole of the substrate 1.

At this time, the head of the screw 8 is kept a little apart from the shutter plate 4.

Next, the operation of this embodiment will be explained.

When the shutter plate 4 is in a stable state at rest, the magnets 5 of the shutter plate 4 are attracted to each other by the attractive force of the magnets 3 of different polarities on the substrate 1, and are in close contact with each other.

Therefore, since the shutter hole 6 does not overlap the lens hole 2, the light beam is blocked.

In this state, push the actuating piece 7 to move the shutter plate 4 to the first position.
Rotate the pressure in the figure.

Then, the shutter plate 4 is separated by magnets 3 of different polarities.
, 5 and the repulsive force of the magnets 3 and 5 of the same polarity as they approach each other.
The magnets 5 of the shutter plate 4 are then placed on top of the magnets 3 of the same polarity on the array substrate 1.

Therefore, the shutter plate 4 is lifted up by the repulsive force of the magnets 3 and 5 of the same polarity, and is no longer subjected to the frictional resistance between the magnets 3 and 5.

Then, from the time when this state is slightly exceeded, the magnet 5 of the shutter plate 4 has a repulsive force with the magnet 3 of the same polarity of the substrate 1 located at the corresponding position, and the magnet 5 of the opposite polarity of the next arranged substrate 1. 3, the shutter plate 4 suddenly rotates by one-sixth of a rotation, and the magnets 3 and 5 of different polarities come into close contact with each other and stop rotating.

That is, the shutter plate 4 is moved by the magnet 3°5 at the first manual operation.
rotated by the operator against the attractive and repulsive forces of
The latter hand movement automatically causes rapid rotation due to the attractive and repulsive forces of the magnets 3 and 5, and during the latter half of the rapid rotation, the repulsive force of the magnets 3 and 5 gradually decreases. The attractive force of the magnets 3 and 5 increases accordingly, so they rotate at a stable speed, and during the rapid and stable rotation in the second half,
The shutter aperture 6 and the lens aperture 2 overlap, and the light beam irradiates the lens aperture 2 from the shutter aperture 6, and the exposure is completed.

This series of operations functions as a constant speed shutter device.

Note that the shutter plate 4 rapidly rotates during the second half of the manual operation due to the attractive force and repulsive force of the magnet 3.5, but when the second half of the manual operation is rotated by one-sixth of a rotation, the shutter plate 4 rotates rapidly due to the attractive force and repulsive force of the magnet 3.5. K, shutter plate 4 as in the stationary stable state
The magnet 5 of the substrate 1 and the magnet 3 of different polarity of the substrate 1 are in close contact with each other, and the magnet 5 of the shutter plate 4 is in the corresponding position.
The shutter plate 4 receives an attractive force from the magnets 3 of different polarity and a repulsive force from the magnets 3 of the same polarity of the array substrate 1.
Further rotation of the lens is prevented, ensuring that more than one second exposure is performed.

Further, the initial manual movement of the shutter plate 4 is performed by the operator, and at this time, as shown in FIG. In addition, when this protruding actuating piece 7 is pushed downward along one side of the board 1, six magnets 3 are arranged at equal intervals, so that six magnets 3 are arranged at equal intervals. If the operating piece 7 is made so that it no longer protrudes from the base plate 1 at the position where it has been rotated by a little more than one-quarter of a turn, that is, at the lower position on one side of the base plate 1, the operator can simply move the fingertip upward along one side of the base plate 1. By simply moving the shutter plate 4 downwards, it is possible to ensure that only the first half of the manual movement of the shutter plate 4 is performed. Therefore, the shutter plate 4 does not return backward, and moreover, the operator's fingertips are not affected by the second half of the manual movement. does not act as a resistance, so the exposure time is always constant.

Note that the shutter plate 4 may be operated by any suitable means other than the actuating piece 7 described above. For example, as shown in FIG. The shutter plate 4 may be directly operated by having a little more than one portion protrude from one side of the substrate 1.

In the above embodiment, the magnets 3 of different polarities on the substrate 1 are N and S.
, N, and S are arranged alternately, but N
, S, S, N or N, S, S, S, N, a large number of magnets of different polarities may be arranged between the same poles. For example, when the magnet 5 of the shutter plate 4 is set to the S pole. , shutter plate 4
During the second half of the hand movement, the magnet 5 receives the repulsive force of the plurality of magnets 3 with the same polarity, so the speed at which it moves between the last same-polarity S and the next different-polarity N becomes faster (the shutter speed becomes faster). can be made faster.

Note that this was confirmed through experiments.

According to the present invention, the shutter plate has rotational mobility from a stable state to the next stable state due to the arrangement of magnets as one movement, and the shutter plate can perform the subsequent manual movement by making the first manual movement of the one movement. The operation is performed automatically and rapidly by the repulsive force of the magnets of the same polarity and the attractive force of the magnets of the different polarity, and moreover, during this latter half of the sudden rotation, the repulsive force of the magnets of the same polarity gradually increases. However, the attractive force of the magnets of different polarities increases accordingly, so it rotates at a stable speed, and after the second half of the manual movement, it returns to a stable state due to the arrangement of the magnets, and no further rotation is possible. blocked.

Therefore, during the rapid and stable rotation in the second half, exposure can be performed by aligning the shutter hole with the lens hole, and the shutter plate does not require reciprocating movement, so the structure is simple, and the magnet A fixed-speed shutter device that can operate reliably by using the suction and repulsion forces of can be provided.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of a shutter device for a camera according to the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a front view of a modified example thereof. 1...Substrate, 2...Lens hole, 3, 5...Magnet, 4...
Shutter plate, 6...One hole for shutter.

Claims (1)

[Claims] 1 A shutter plate 4 having a shutter hole 6 formed at a peripheral position overlapping with the lens hole 2 is rotatably supported on a substrate 1 having a lens hole 2, and a shutter plate 4 having a shutter plate 40 at the rotation center is rotatably supported on the substrate 1. A plurality of magnets 3 are arranged around the substrate 1 with their polarities sequentially changed, and magnets 3 of one polarity of the substrate 1 are attracted to the center of rotation of the shutter plate 4, while magnets 3 of the other polarity are arranged around the center of rotation of the shutter plate 4. A magnet 5 is arranged to repel the
The shutter hole 6 opens the substrate 1 from the time when, when the shutter plate 4 is rotated in the operating rotation direction, the magnet 5 approaches the repelling magnet 3 of the other polarity of the substrate 1. A shutter device for a camera, characterized in that the lens hole 2 is formed at a position that coincides with the lens hole 2 until the magnet 3 of one polarity attracts the magnet 3 again.