JPH052900Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a so-called electromagnetic drive shutter device for a camera that controls exposure by opening and closing a shutter blade by exciting and demagnetizing an electromagnet.

[Conventional technology]

2. Description of the Related Art Conventionally, as a camera shutter using an electromagnet including a suctionable armature as a driving source, for example, a technique described in Japanese Patent Application Laid-Open No. 116633/1984 is known.

In such camera shutters, the armature is attracted by being excited by electricity,
Along with this, the shutter opening/closing member is driven, and at the same time, the force for closing the shutter is charged, and exposure for photographing is started by opening the shutter blade, and by releasing the suction of the armature by demagnetizing, exposure is performed. In a camera shutter for closing the shutter, when the electromagnet attracts the armature in response to a signal from the control circuit, the armature and the opening/closing member are directly connected, so the initial speed at the start of suction is slow and the force is small.

In particular, the recent trend towards miniaturization has led to the use of smaller batteries as a power source, which causes the voltage to drop more quickly, resulting in the inconvenience that small cameras have short battery life and fewer shots. It was hot.

This is because when a voltage drop occurs, the attraction force of the electromagnet device decreases, and when the armature is running, the initial speed decreases especially significantly, making it difficult to operate the shutter opening/closing member smoothly, causing variations in exposure, and extreme In such cases, it would become inoperable.

In order to eliminate these disadvantages, various techniques have been proposed, such as delaying the start of operation of the shutter opening/closing member from the armature suction of the electromagnetic device, as shown in Japanese Patent Publication No. 61-4094.

However, new inconveniences have arisen, such as the need for a locking member to delay the start of operation, which increases the number of parts.

[Purpose of invention]

SUMMARY OF THE INVENTION In view of the above-mentioned disadvantages, an object of the present invention is to provide an electromagnetic drive shutter device that is less affected by voltage drop despite having a simple configuration.

[Structure of the idea]

The purpose of the present invention described above is to provide a distance (gap) for the armature to run idly at the connection between the armature of the electromagnet device and the shutter opening/closing member, and to accelerate the running of the armature during this gap to increase the driving force. It can be obtained by

[Example of idea]

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

Reference numeral 1 denotes an electromagnetic device which attracts the armature 2 against the spring 2a by being energized by a control circuit (not shown), and separates and releases it by being demagnetized.

A connecting plate 3 has an opening 3c including an upper edge 3a and a lower edge 3b, and operates together with the operation of the armature 2 of the electromagnetic device 1.

Reference numeral 4 denotes a closing drive lever, which is rotatably supported on a shaft 4a, and has a pin 4b installed at one end that fits into the opening 3c of the connecting plate 3, and a pushing part 4c at the other end. It is biased clockwise by a spring 4d.

Reference numeral 5 denotes an opening/closing lever, which is connected to a shutter blade (not shown), rotatably attached to a shaft 5a, biased counterclockwise by a spring 5b, and one end of which is connected to a shutter blade (not shown), which is urged counterclockwise by a spring 5b. A pin 5c that comes into contact with the portion 4c is planted.

In addition, the closing drive lever 4 or the opening/closing lever 5
At least one of them is a known regulating member (not shown)
The rotation range is restricted by the shutter blade, and the figure shows a state in which the shutter blade is biased and restricted to be positioned on the closing side.

6 is a trigger switch, and when the two contact members are separated, the exposure calculation circuit starts calculation.

The operation will be explained below.

When the photographer releases the shutter from the illustrated pre-operation state, the electromagnet device 1 is excited by electricity from the control circuit.

This excitation attracts the armature 2, and the connecting plate 3 supported by the armature 2 moves downward in the drawing against the spring 2a together with the armature 2.

At this time, a return force for closing the shutter blade in the latter half of the exposure is charged by the spring 2a.

When the connecting plate 3 starts moving downward, the lower edge 3
b separates from the pin 4b set on the closing drive lever 4, but at this point the opening/closing lever 5 is pushed away from the pushing part 4 of the closing drive lever 4, which is biased by the spring 4d.
Since the shutter blade (not shown) is prevented from moving by c, the shutter blade (not shown) has not moved to the opening operation.

The attraction of the electromagnetic device 1 continues, and the armature 2 advances while accelerating and increasing the force due to inertia, and the upper edge 3a of the opening 3c of the connecting plate 3 closes and comes into contact with the pin 4b of the drive lever 4. Push downward.

A closing drive lever 4 that is pushed via a connecting plate 3 by an armature 2 that has accumulated sufficient force is connected to a shaft 4.
It rotates to the left (counterclockwise) about point a against the force of the spring 4d, and the pushing part 4c releases the lock of the shutter opening/closing lever 5.

Then, the shutter opening/closing lever 5 starts turning right around the shaft 5a due to the return force of the spring 5b, and opens the shutter blade (not shown), and in conjunction with this, the pin 5c reverses the trigger switch 6 from on to off.

As a result, the exposure calculation circuit starts calculation and counts the time until the shutter closes.

Next, the control circuit, informed by the arithmetic circuit that the predetermined exposure time has ended, cuts off the power to the electromagnet device 1 and demagnetizes it.

The demagnetized electromagnetic device 1 releases the attraction of the armature 2, and the armature 2 moves upward by the restoring force of the spring 2a, which has already been charged during the first half of the exposure operation.

The closing drive lever 4, whose rotation to the right has been locked by the connecting plate 3, is released from the lock by the movement of the upper edge 3a, and is therefore rotated clockwise by the return force of the spring 4d.

At this time, the pushing part 4c at the tip rotates while pushing the pin 5c of the shutter blade opening/closing lever 5, so the shutter blade closes the photographing aperture window, turns on the trigger switch 6, and performs the exposure operation. end.

[Other Examples]

In this embodiment, an opening into which the closing drive lever 4 is fitted is provided in the connecting plate 3, which is a separate member from the armature 2;
It goes without saying that there is no problem in forming it integrally with the end of the.

Further, the opening of the connecting plate may have another shape such as a U-shape.

It goes without saying that a mechanical governor may be applied to the opening/closing lever 5.

[Effect of idea]

As described above, by implementing the present invention, an electromagnetic drive shutter device can be obtained which reduces the influence of a drop in power supply voltage by using a simple mechanism, instead of the conventional disadvantage that exposure accuracy becomes inaccurate when the power supply voltage drops. be able to.

[Brief explanation of the drawing]

The drawing is a side view showing an embodiment of the present invention. 1... Electromagnetic device, 3... Connection plate, 3c... Opening, 4... Closing drive lever, 5... Opening/closing lever.

Claims (1)

[Claims for Utility Model Registration] (1) An opening/closing member that opens and closes the shutter blade; a first biasing member that biases the opening/closing member in the blade opening direction; a closing member that comes into contact with the opening/closing member; a second biasing member that biases the opening/closing member so as to push the opening/closing member in the blade closing direction; and a movable armature that is energized. an electromagnetic device that generates a force that displaces the armature by demagnetizing the armature, and a third biasing member that biases the armature in a direction away from the electromagnet device; An electromagnetic drive shutter device comprising a connecting member integrally supported so as to be displaceable and having an opening at the other end that loosely fits into the closing actuating member, the connecting member forming the opening of the connecting member. At the edge, between the rear end edge in the traveling direction in the exposure operation and the part where the closing operation member abuts and is pushed, there is a pin provided complementary to both members and an opening wider than the diameter of the pin. are fitted loosely and a gap is provided by the third biasing member, and the strength of the second biasing member is greater than the strength of the first biasing member, The closing actuating member is displaced against the second biasing member in the middle of the suction operation of the armature so that the shutter opening operation is delayed compared to the suction timing of the armature and starts the shutter opening operation. Electromagnetic drive shutter device. (2) The trigger switch member is arranged with a force in a direction that resists the second biasing member, and the force of the second biasing member is equal to the force of the first biasing member and the force of the trigger switch member. Claim 1 for registration of a utility model, characterized in that the scope is large compared to the sum of the competence and competence.
The electromagnetic drive shutter device described in .