JPH0455308Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a so-called setless camera shutter having an electromagnetic device that releases the shutter when it is energized and ends exposure when it is demagnetized.

[Conventional technology]

Releases the shutter by being excited,
In camera shutters that use an electromagnetic device that ends exposure when demagnetized, when the battery voltage drops and the attraction force of the electromagnetic device decreases, the operating speed of the armature at the initial stage of attraction, which is already slow, will further decrease. The unlocking operation of the locking member of the opening/closing member driven by the electromagnetic device is delayed, and a situation arises in which the opening/closing member operates while remaining in contact with the locking member, resulting in variations in the amount of exposure. There is a problem with this.

Therefore, as a countermeasure, for example,
The camera shutter described in Publication No. 4094 is configured to charge the opening spring when the electromagnetic device is attracted, and in the final stroke, that is, in the region where the suction operation speed is high, release the lock of the opening/closing lever and charge the closing spring. However, due to the operating characteristics of the electromagnetic device, the opening spring must be charged at the beginning of the suction operation when the suction force is relatively weak, which creates the problem that the voltage applied to the electromagnetic device must be set high. It was hot. Also, it is necessary to strengthen the spring that acts as a return force against the opening spring when each member returns to its original position, that is, the closing spring, but if it is made quite strong, the attraction force of the electromagnetic device when the shutter is operated will be strengthened. As a result, the minimum applied voltage increases, shortening the battery life, and, on the other hand, if it is weakened, the restoring force becomes weaker, making it difficult to restore.There is a contradiction in that. However, since this camera shutter had only one closing spring, it was difficult to resolve the above-mentioned contradiction.

[Problem that the invention attempts to solve]

In view of the above-mentioned problems, the present invention makes it possible to set the applied voltage to the electromagnetic device at a low level without variations in the exposure amount, ensure the closing operation, and facilitate the return of each member to its original position. The purpose is to provide a camera shutter.

[Means and actions for solving problems]

A camera shutter according to the present invention includes an electromagnetic device that releases the shutter when it is energized and ends exposure when it is demagnetized. a shutter opening/closing member that opens the shutter blade by forward movement and closes the shutter blade by backward movement against bias; is biased by a first restraining member which restrains the shutter opening/closing member and whose other end is connected to an operating portion of the armature in the electromagnetic device, and a second closing spring which is pivotally attached to the board and is stronger than the opening spring. a second restraining member whose one end restrains the shutter opening/closing member and whose other end is located away from the actuating part of the armature and is pushed by the actuating part when the electromagnetic device is excited; When energized, the first restraining member is first rotated in the direction of releasing restraint against the first closing spring, and after a predetermined stroke delay, the second restraining member also releases restraint against the second closing spring. is forced to rotate in the direction,
Furthermore, when the electromagnetic device is demagnetized, the first and second restraining members work together to cause the shutter opening/closing member to move back against the opening spring, so that the middle phase of the attraction operation of the electromagnetic device is prevented. From then on, the restraint on the shutter opening/closing member is released, and the load on the electromagnetic device is initially due to only one spring, but after the middle stage, the load on the electromagnetic device is the sum of the load due to two springs. It is designed to change according to the operating characteristics of the electromagnetic device. Further, when each member returns to its original position, there are two springs, the first and second closing springs, which act against the other springs.

〔Example〕

Hereinafter, the present invention will be explained in detail based on an illustrated embodiment.

FIG. 1 is a plan view showing the initial state of the shutter for a camera according to the present invention, in which 1 is a shutter board having an exposure opening 1a and a slot 1b; A pair of shutter blades 3, which open and close, are pivotally mounted on the upper surface of the substrate 1, and are connected to the shutter blades 2, 2 by a pin-slot connection via a pin 3a implanted at one end thereof and passing through the slot 1b. A shutter opening/closing lever 5 is connected to the other end of the opening/closing lever 3 and is biased by an opening spring 4 in the right rotation direction (opening direction) in FIG. The governor is interlocked with the opening/closing lever 3 and has a built-in one-way (opening direction) clutch mechanism. Reference numeral 6 is pivotally mounted on the substrate 1, and one end 6a is engaged with the pin 3b (first position) to restrain the opening/closing lever 3, and the first closing spring 7
The first restraining lever 8 biased in the clockwise rotation direction (closing direction) in FIG. an electromagnetic device connected to 6b by a pin-slot connection and controlled by an exposure time control circuit (not shown);
is pivotally connected to the base plate 1 coaxially with the first restraining lever 6, and a downward bent portion 9a provided at one end is engaged with the side edge (second position) of the opening/closing lever 3 in order to restrain it. The second closing spring 10 urges the clockwise rotation direction (closing direction) in FIG. This is the second deterrent lever. Note that the second closing spring 10 is the opening spring 4.
It is assumed that the setting is stronger than . Further, it is desirable that the first closing spring 7 is set to be weaker than the second closing spring 10 and the opening spring 4.

Since the camera shutter according to the present invention is constructed as described above, when the shutter is first released, the electromagnetic device 8 is excited by the exposure time control circuit (not shown) and the armature 8a is attracted downward in FIG. At the beginning of the operation, only the first restraining lever 6 is rotated to the right against the first closing spring 7, that is, while charging the first closing spring 7. At this time, the first restraint lever 6 releases the restraint on the pin 3b of the opening/closing lever 3, that is, the restraint at the first position, but the lower bent portion 9a of the second restraining lever 9 still remains on the opening/closing lever 3. Since the second closing spring 10 is in contact with the side edge and is stronger than the opening spring 4, the opening/closing lever 3 does not move.

Next, when the armature 8a further moves downward in FIG. 1, that is, in the middle stage of the suction operation, the pin 8b
begins to push the second deterrent lever 9 as shown by the dashed line in FIG. While doing so, he was forced to rotate to the left. At this time, the attraction force of the electromagnetic device 8 increases rapidly as the stroke S of the armature 8a approaches the end according to its operating characteristics (see FIG. 3), so the first and second restraining levers 6 and 9 rapidly move. As a result, the inhibition of the opening/closing lever 3 by the second restraining lever 9 is instantly released.

Immediately after the restraint is released, the opening/closing lever 3 starts turning to the right by the opening spring 4, and rotates to the right to the position shown by the two-dot chain line in FIG. 2 under the action of the governor 5.
Open the shutter blades 2, 2 and start exposure.

Next, when a predetermined exposure time has elapsed, the electromagnetic device 8 is demagnetized by an exposure time control circuit (not shown), and its attractive force disappears.

When the attractive force of the electromagnetic device 8 disappears, the first and second restraining levers 6 and 9 close the first and second closing springs 7.
and 10, the lower bent portion 9a of the second restraining lever 9 pushes the side edge of the opening/closing lever 3, and one end 6a of the first restraining lever 6 pushes the pin 3b, so that the opening/closing lever 3 Open the clutch and rapidly rotate it to the left (in the non-clutch direction) against the force of spring 4.

By turning the opening/closing lever 3 to the left, the shutter blades 2, 2 are closed, and the exposure is completed. At the same time, each member returns to the position shown in FIG. 1, and the shutter returns to its initial state.

In the above embodiment, the first deterrent lever 6, which is biased by the first closing spring 7, and the second deterrent lever 9, which is biased by the second closing spring 10, are activated during the entire stroke of the closing operation of the shutter blade. Because both levers are pivoted on the same axis in order to work together, the points of action of both levers on the opening/closing lever 3 are different, but if the points of action are the same, the pivot points of both levers must be different. It's fine if you do.

The operating principle of the shutter for a camera according to the present invention has been explained above, but the shutter according to the present invention is used after the middle stage of the suction operation of the electromagnetic device 8, that is, after the electromagnetic device 8 shown in FIG.
As is clear from the operating characteristic curve, the shutter opening/closing lever 3 is released from its inhibition in the region where the suction force becomes stronger and the operating speed becomes faster.
Even if the attraction force of the electromagnetic device 8 is reduced due to a drop in battery voltage, a situation in which the opening/closing lever 3 operates while remaining in contact with the second restraining lever 9 is prevented, and as a result, variations in exposure amount are prevented. Ru. In particular, in the case of the above embodiment, since the operation of the opening/closing release 3 is slowed down by the action of the governor 5,
Its effects are even more remarkable. In addition, the camera shutter of the present invention has an electromagnetic device 8 as shown in FIG.
At the beginning of the suction operation, the load is only due to one spring, that is, the first closing spring 7, and from the middle stage onward, it is the total load of two springs, that is, the first and second closing springs 7 and 10. Since it is designed to change according to the operating characteristics of the electromagnetic device 8, a small amount of spring force is charged at the beginning of the suction operation when the suction force is relatively weak, and a large amount of spring force is charged after the middle of the suction operation when the suction force is strong. Charging is performed, and as a result, the voltage applied to the electromagnetic device 8 can be set low. In addition, in the camera shutter of the present invention, there are two springs, the first and second closing springs 7 and 10, that act against the opening spring 4 when each member returns to its original position, so the returning force is reduced. Strong and easy to return each member to its original position.

Note that the stroke values shown in FIGS. 3 and 4 are not particularly limited.

[Effect of idea]

As described above, the camera shutter according to the present invention allows the voltage applied to the electromagnetic device to be set low without variations in the exposure amount, ensures the closing operation, and allows each member to return to its original position. It has many important practical advantages such as ease of use.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the initial state of an embodiment of a camera shutter according to the present invention, FIG. 2 is a plan view showing changes in the operating position of the main parts of the above embodiment, and FIGS. 3 and 4 are 3 is a graph showing the operating characteristics of the electromagnetic device of the above embodiment in terms of the relationship between stroke and attraction force, and the relationship between time and stroke, respectively. 1... Shutter board, 2... Shutter blade, 3
...Shutter opening/closing lever, 4...Opening spring, 5...
...Governor, 6...First deterrent lever, 7...First closing spring, 8...Electromagnetic device, 9...Second deterrent lever, 10...Second closing spring.

Claims (1)

[Scope of utility model registration request] Releases the shutter by being excited,
In a camera shutter having an electromagnetic device that terminates exposure when degaussed, the shutter blade is pivotally attached to a circuit board and biased by an opening spring, and the shutter blade is opened by the forward movement caused by the bias, and the shutter blade is returned against the bias. a shutter opening/closing member that closes the shutter blade by the action of the shutter; and an actuating portion of an armature in an electromagnetic device, the shutter opening/closing member being pivotally connected to the base plate and biased by a first closing spring, one end of which restrains the shutter opening/closing member, and the other end of which is an electromagnetic device. a first restraining member connected to the base plate, and a second closing spring pivotally connected to the base plate and biased by a second closing spring stronger than the opening spring, one end of which restrains the shutter opening/closing member, and the other end of which is connected to the operating portion of the armature. a second restraining member located at a remote position and pushed by the actuating part when the electromagnetic device is excited; the first restraining member first resists the first closing spring when the electromagnetic device is excited; The shutter opening/closing member is rotated in the restraint release direction against forward movement, and after a predetermined stroke delay, the second restraint member is also rotated in the restraint release direction against the second closing spring, and the electromagnetic device is A camera shutter characterized in that, when demagnetized, the first and second restraining members work together to cause the shutter opening/closing member to move back against the opening spring.