JPH11102000A - Focal plane shutter for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focal plane shutter for a camera constituted so that a set member is surely returned to an initial position before the exposure actions of a driving member for a first blade and a driving member for a second blade are started. SOLUTION: Since the set member 8 is locked by the lock part 12a of a lock member 12 in a set state, the parts to be pressed 4b and 6b of the driving member for a first blade 4 and the driving member for a second blade 6 are suppressed by the respective pressing parts 8a and 8b of the set member 8 so that the rotation thereof by respective driving springs 5 and 7 is suppressed. The lock state of the set member 8 is released by the lock member 12 at a photographing time. However, when the set member 8 is not immediately rotated by the pressing force of a return spring 10 for some reason, the part to be pressed 8f thereof is pressed by the pressing part 12b of the lock member 12 just after the above mentioned lock state is released so that the set member 8 can be returned to the initial position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In the present invention, in photographing, a front blade group and a rear blade group are sequentially operated in the same direction, and a film is exposed by slits formed by slit forming blades of both blade groups. The present invention relates to a focal plane shutter for a camera.

[0002]

2. Description of the Related Art Recently, a typical focal plane shutter has two main plates each having an opening at a substantially central portion (a main plate arranged on a lens side in a camera is called a shutter main plate, and The base plate to be placed is called a cover plate, an auxiliary base plate, etc.), and they are attached to each other with a predetermined space therebetween, and the space is partitioned by an intermediate plate placed between the two base plates to form two blades. Make up the room. The intermediate plate also has an opening formed in a substantially central portion, and is arranged so as to overlap with the openings of the two base plates, thereby forming a rectangular exposure opening centered on the optical axis. ing.

In the two blade chambers, a front blade group and a rear blade group are arranged, respectively. Each blade group is usually composed of two arms and a plurality of blades, respectively, and the arm is rotatably attached at one end thereof to the base plate, and is provided with a plurality of blades toward the other end. Are pivoted in turn. Also,
One of the two arms of each blade group is a main arm and has a long hole formed therein, and the long hole has an operating pin of the driving member for the front blade and an operating pin of the driving member for the rear blade. Are fitted. And, the rotational axis positions of these four arms are arranged so as to be substantially linear at one side position of the opening.

A mechanism for causing each of the blade groups to open and close is mounted on the surface of the shutter base plate (the surface that becomes the lens side of the camera).
No. 33945. As can be seen from this conventional example, the driving member for the front blade and the driving member for the rear blade are rotated at a position lateral to the opening forming the exposure opening and at a position far from the opening. Mounted as possible. The set member (set lever) is rotatably mounted at a position closer to the opening than the set member, and at the time of setting, both the front blade drive member and the rear blade drive member are operated to the set position. I have.

[0005] This set member is used for setting operation.
The camera is rotated by the member on the camera body side from the initial position against its own return spring, and the set position is held by the member on the camera body side until the next photographing is performed. At the time of shooting, prior to the exposure operation of each driving member, the holding force of the member on the camera body side is released, so that the set member is returned to the initial position by its own return spring, and the exposure of each driving member is performed. Enables operation. However, such a configuration requires that the member on the camera body side be stopped at a predetermined position during the set operation, and that the set position is relatively severe. The adjustment work was extremely troublesome when assembling the camera into the camera body.

Therefore, it is conceivable to provide a locking member for the set member on the shutter unit side so that the locking member can hold the set member at a predetermined position at the set position of the set member. I have. Accordingly, the member on the camera body side only needs to operate the set member at least to a position where it is locked by the locking member. Even if the overrun varies,
When the contact with the set member is lost, the set member is slightly returned by the return spring, and is held at the predetermined set position by the locking member. Therefore, it is not necessary to strictly adjust the set operation amount of the member on the camera body side, and the assembling work of the shutter unit becomes easy. However, as can be seen from the above, the locking of the locking member must be released prior to the exposure operation, but in that case, the locking is merely released, so that the member on the camera body side to be released is released. The working amount does not require any particular precision. The present invention relates to a focal plane shutter for a camera having such a configuration.

[0007]

By the way, in most recent cameras, the shutter is automatically set when photographing is completed. Therefore, the shutter
When the camera is not used, each drive spring is in a tensioned state. The shutter having the above-described configuration, which is the object of the present invention, is not an exception, and is almost always used for a camera having such specifications. However, if the set state continues for a long time, the adhesive phenomenon occurs between the contact members due to the influence of temperature, humidity, fine dust, contact pressure and the like. And this phenomenon, in particular,
This is remarkable between members made of synthetic resin.

In the case of the leading blade driving member and the trailing blade driving member, even if there is a little, they can be operated without any problem because they are urged by a strong driving spring. Is not the case even with the same rotating parts. If an adhesive phenomenon occurs on the contact surface with the rotating shaft or the contact surface with each drive member, the return force may not be restored only by the biasing force of its own return spring. The operation does not start at the moment when the locking of the stop member is released, and a slight timing shift may occur. Therefore, when such phenomena occur, the exposure operation of the leading blade driving member is hindered by the set member, and the exposure operation cannot be performed properly.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. It is an object of the present invention to provide a locking device that can be locked even before the exposure operation even if the above-mentioned adhesion phenomenon occurs. An object of the present invention is to provide a focal plane shutter for a camera, in which a set member can return to an initial position without delay when a member releases locking of a set member.

[0010]

In order to achieve the above object, a focal plane shutter for a camera according to the present invention comprises:
A front blade drive member having a pushed portion and actuated by the front blade drive spring during the exposure operation to open the front blade group, and a rear blade having the pushed portion during the exposure operation; A driving member for the rear blade that is actuated by the driving spring for the rear blade group to perform a closing operation, and two pressing portions and one driven portion, and from the initial position by the member on the camera body side at the time of setting. Actuated against its own return spring, the two pushing members individually push the pushed portions of the respective driving members, thereby operating the respective driving members to the set positions against the respective driving springs. At the time of release, the set member is returned to the initial position by the return spring prior to the exposure operation of each of the driving members, and the pressing member has a pushing portion to lock the set member against the return spring at the set position. At the time of release, Prior to the exposure operation of the member, the member on the camera body side is actuated to release the lock, and if the set member does not immediately return even if the lock is released, the push-moving portion is moved by the cover member of the set member. A locking member configured to press the pressing portion in the return operation direction. Also,
Preferably, when the set member returns from the set position to the initial position, the driving member for the front blade and the driving member for the rear blade slightly follow each other by the respective drive springs when the set member returns to the initial position. It is locked by each locking member at the operation start position, and at the time of exposure operation, the locking is released sequentially. In the focal plane shutter for a camera according to the present invention, preferably, the driving member for the front blade and the driving member for the rear blade each include an iron piece member, and when the set member returns from the set position to the initial position. The iron piece members are attracted to the electromagnet for the front blade and the electromagnet for the rear blade, respectively.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to an embodiment shown in FIGS. FIG. 1 is a plan view showing a set state. FIGS. 2 to 4 are plan views for explaining the operation from the set state shown in FIG. 1 until the driving member for the front blade and the driving member for the rear blade reach the exposure operation start position. FIG. 3 shows a state immediately after the locking member releases the locking of the set member. FIG. 4 shows a state immediately after the locking member releases the locking of the set member. It shows the state where it was turned on. FIG. 5 is a plan view showing a state immediately after the end of the exposure operation.

First, the configuration of this embodiment will be described. In a substantially central portion of the shutter base plate 1, an opening 1
a is formed. However, the configuration on the right side from the opening 1a is not particularly important for the present invention, and is not shown. Although not shown, as is well known,
On the back side of the shutter base plate 1 (the film side in the camera), an intermediate plate and an auxiliary base plate are sequentially mounted. Between the shutter base plate 1 and the intermediate plate, a blade chamber of a group of front blades is provided. Between them, a blade chamber of the rear blade group is formed. Further, the opening 1a is provided in the intermediate plate and the auxiliary base plate.
An opening having a shape similar to the above is formed. By arranging these three openings so as to overlap each other, a rectangular exposure opening centered on the optical axis is formed.

The shutter base plate 1 is formed with three arc-shaped holes 1b, 1c, 1d and a circular hole 1e.
Among them, the upper edges of the arc-shaped holes 1b and 1c are
Well-known cushioning members 2 and 3 made of an elastic material such as rubber and having a C-shaped planar shape are attached. Further, the shafts 1f, 1g, 1h,
1i, 1j, 1k, and 1m are erected. Of these shafts, shafts 1h, 1i, and 1j are erected on the front side of shutter base plate 1, and shafts 1k and 1m are erected on the back side, while shafts 1f and 1g penetrate through shutter base plate 1. It has a shaft on both the front side and the back side.
Although not shown, a well-known support plate and a printed wiring board are mounted on the front side of the shutter base plate 1 at the ends of the shafts 1f, 1g, 1h, and 1j so as to be parallel to the shutter base plate 1. Have been.

Although FIG. 1 does not show the leading blade group and the trailing blade group, each blade group in this embodiment is provided with two arms and a pivotal support at different length positions, as is well known. It consists of a plurality of blades. On the back side of the shutter base plate 1, the two arms of the front blade group are on the shafts 1f and 1k, and the two arms of the rear blade group are on the shaft 1f.
g and 1 m are rotatably mounted respectively. Further, the arm attached to the shafts 1f and 1g is formed with a long hole to be fitted to an operation pin of each drive member described later.

On the front side of the shutter base plate 1, a shaft 1f
The front blade drive member 4 is rotatably attached to the drive shaft. The front blade driving member 4 has an operating pin 4a on the back side.
And a pushed portion 4b, and a projection 4c on the surface side. The operating pin 4a penetrates the arc-shaped hole 1b, and its root has a circular cross-sectional shape so that it can abut on the buffer member 2. The operating pin 4
The leading end of a has a cross section similar to an oval, and is fitted in a long hole of an arm attached to the shaft 1f on the rear side of the shutter base plate 1. Then, the front blade driving member 4
Is urged by the leading blade drive spring 5 to rotate in the counterclockwise direction.

Similarly to the shutter base plate 1, a rear blade drive member 6 is rotatably mounted on the shaft 1g.
The rear blade drive member 6 has an operating pin 6a and a pushed portion 6b on the back side, and has a projection 6c on the front side. The operating pin 6a penetrates the arc-shaped hole 1c, and a root having a circular cross section can come into contact with the cushioning member 3. In addition, the tip whose section is oval,
On the back side of the shutter base plate 1, it is fitted into a long hole of an arm attached to the shaft 1 g. The rear blade drive member 6 is urged by a rear blade drive spring 7 to rotate counterclockwise.

A set member 8 and a locking member 9 for the rear blade are attached to the shaft 1h of the shutter base plate 1 so as to be rotatable separately. The set member 8 is formed with two pushing portions 8a and 8b. The pushing portion 8a pushes the pushed portion 4b of the leading blade driving member 4, and the pushing portion 8b acts as a trailing blade driving member. 6 to be pushed. The set member 8 is further provided with a pushed portion 8c and an engaging portion 8d, and a pin 8e is provided on the back side, and the pushed portion is pushed radially from the thick portion on the back side. Part 8f
Are formed. The pushed portion 8c is a portion that is pushed upward by a member on the camera body side (not shown). The pin 8e is inserted into the arc-shaped hole 1d of the shutter base plate 1, but has a length such that its tip does not protrude to the rear side of the shutter base plate 1.
The set member 8 having such a shape is provided with the return spring 1.
It is urged to rotate clockwise by 0.

The shape of the locking member 9 for the rear blade is extremely simplified. The rear blade locking member 9 is actually urged to rotate clockwise by a spring (not shown), and is positioned by the stopper 11 provided on the support plate (not shown). The rear blade drive member 6 can be seen within the operation locus of the projection 6c. Further, during photographing, when the energization of the electromagnet for the rear blade provided on the support plate is cut off during photographing, the rear member is rotated in a counterclockwise direction by a member operated thereby. It has become so.

A locking member 1 is attached to a shaft 1i of the shutter base plate 1.
2 is rotatably mounted and urged by a spring 13 to rotate clockwise. This locking member 12
A locking portion 12a for locking the engaging portion 8d to prevent the returning operation of the set member 8, a pushing portion 12b for pushing the pushed portion 8f of the setting member 8, and a hole in the shutter base plate 1. 1e
Are formed, and a pushed portion 12d pushed by a member on the camera body side is formed. Of these, the regulating portion 12c regulates the rotation angle of the locking member 12 so as not to hinder the assembling of other members at the time of assembly, and has no functional relationship. Configuration.

A front blade locking member 14 is rotatably attached to the shaft 1j of the shutter base plate 1. The front blade locking member 14 is shown in a simplified form, similarly to the rear blade locking member 9 described above, and the actual configuration is similar to the rear blade locking member 9. That is, the locking member 1 for the front blade
4 is biased by a spring (not shown) so as to rotate clockwise, is positioned by a stopper 15 provided on the support plate, and is actuated by a protrusion 4c of the leading blade drive member 4. You can come inside. Further, when the energization of the front blade electromagnet provided on the support plate is cut off during photographing, the front blade locking member 14 is rotated in a counterclockwise direction by a member operated thereby. It has become.

Next, the operation of this embodiment will be described. FIG. 1 shows a setting state of the shutter, in which the engaging portion 8 d of the set member 8 is attached to the engaging portion 12 a of the engaging member 12.
Are engaged, and the rotation of the set member 8 in the clockwise direction by the return spring 10 is prevented. At this time, the front blade drive member 4 and the rear blade drive member 6
The pushed parts 4b and 6b are the pushing parts 8 of the set member 8.
a, 8b, so that it cannot be rotated in the counterclockwise direction by the drive springs 5, 7. In this state, the plurality of blades of the front blade group are in the unfolded state and cover the opening 1a, and the plurality of blades of the rear blade group are in the superimposed state and are located below the opening 1a. Is stored.

In photographing, when the release button of the camera is pressed, the power switch is closed at an initial stage (some cameras have the power switch closed before the release button is pressed). When the electromagnet is energized, each of the well-known release members (often referred to as an iron piece lever) is attracted and held against its own operation habit. Therefore, a holding member (not shown) (often referred to as a hold lever) retreats from a position where the release member has been in contact with the electromagnet.
Almost at the same time, focusing and mirror-up operation by the automatic focus adjustment device are performed, and the pushed portion 12d of the locking member 12 is pressed by a member (not shown) on the camera body side. Is rotated counterclockwise against the urging force of the spring 13.

The rotation of the locking member 12 causes the locking portion 1 to rotate.
FIG. 2 shows the state at the moment when the engagement between the engagement portion 8a and the engagement portion 8d is released. In this state,
The pushing portion 12b of the locking member 12 has not yet contacted the pushed portion 8f of the set member 8. When the locking by the locking member 12 is released in this way, the set member 8 immediately rotates clockwise by the urging force of the return spring 10 in a normal case. However, in particular, when the apparatus is left in the set state for a long period of time, for example, the adhesive action occurs at the bearings of the set member 8 and the contact parts with the drive members 4 and 6, There is a case where the setting member 8 does not immediately rotate clockwise. In such a case,
The pushing portion 12b pushes the pushed portion 8f. Indeed,
The state at that time is shown in FIG.

In any case, when the set member 8 is rotated clockwise by the urging force of the return spring 10 in this manner, the pushing portions 8a and 8b of the set member 8 and the pushing members 8a and 8b of the driving members 4 and 6 are pushed. The contact relationship with the moving parts 4b, 6b is released, and the respective driving members 4, 6 rotate counterclockwise by the urging forces of the respective driving springs 5, 7. However, the rotation of each of the driving members 4 and 6 is stopped only by a slight rotation due to the protrusions 4c and 6c abutting on the locking member 14 for the front blade and the locking member 9 for the rear blade. . The state at that time is shown in FIG. For each of the driving members 4 and 6, the position at this time is the start position of the exposure operation, and even by the operation up to this position, the blades of the front blade group still cover the opening 1a. The blades of the blade group are located below the opening 1a. And the set member 8
Makes the pin 8e abut on the upper edge of the arc-shaped hole 1d,
It has returned to its initial position.

Thereafter, the exposure time control circuit is activated by the end signal of all the preparatory operations such as the automatic focusing described above. First, the power supply to the electromagnet for the first blade is cut off, and the counting of the exposure time is started. Then, the release member (not shown) which is attracted and held by the leading blade electromagnet,
It operates according to its own operation habit, and the locking member 14 for the leading blade
Is rotated counterclockwise against the urging force of a spring (not shown). As a result, the engagement with the projection 4c is released, and the leading blade drive member 4 is rapidly rotated counterclockwise by the urging force of the leading blade drive spring 5. Therefore, the plurality of blades of the leading blade group are operated upward from the deployed state covering the opening 1a, and open the opening 1a while increasing the amount of overlap with the adjacent blade. Then, after the respective blades are in a superimposed state and completely retreat from the opening 1a, the operating pin 4a of the leading blade driving member 4 comes into contact with the buffer member 2, and the impact is absorbed to stop.

When a predetermined time has elapsed since the start of the exposure operation of the front blade group, the power supply to the electromagnet for the rear blade is cut off by an output signal from the exposure time control circuit. Thereby, the release member (not shown) is activated by its own operating behavior, and rotates the locking member 9 for the rear blade counterclockwise against the urging force of the spring (not shown). Thereby, the engagement with the projection 6c is released.
The rear blade drive member 6 is rapidly rotated counterclockwise by the urging force of the rear blade drive spring 7. As a result, the plurality of blades of the rear blade group are operated upward from the superimposed state stored at the lower position of the opening 1a, and are deployed while reducing the amount of overlap with the adjacent blades, thereby opening the opening 1a. Will be closed. Then, at the stage where the opening 1a is completely covered, the operating pin 6a of the rear blade drive member 6 comes into contact with the cushioning member 3, absorbs the impact, and stops. FIG. 5 shows a state immediately after the end of the exposure operation.

When the photographing is completed in this way and the film is automatically wound up, the member on the camera body side pushes the pushed portion 8c of the set member 8 upward in FIG. , Set operation is performed. On the other hand, at almost the same time, the members related to the respective electromagnets are also set, and the holding member (not shown) operates the release member so as to contact the electromagnets. The locking member 9 for the rear blade rotates clockwise by the urging force of a spring (not shown), and
1 is brought into contact.

When the pushed member 8c is pushed by a member (not shown) of the camera body, the set member 8 rotates counterclockwise from the initial position against the urging force of the return spring 10. In the process, first, the pushing portion 8a pushes the pushed portion 4b, and the front blade driving member 4 is rotated clockwise against the front blade driving spring 5. When the overlap between the slit forming blades of the front blade group and the slit forming blades of the rear blade group reaches a predetermined amount, the pushing portion 8b pushes the pushed portion 6b, and the rear blade driving member 6 is moved backward. It starts rotating clockwise against the blade drive spring 7. Therefore, there is no light leakage from between the two slit forming blades of the leading blade group and the trailing blade group, and each blade of the leading blade group reduces the overlap with the adjacent blade, Each blade is operated downward while increasing the overlap with the adjacent blade.

In this setting operation, the projections 4c and 6c of the driving members 4 and 6
After temporarily pressing counterclockwise 4, 9 counterclockwise, set member 8
Is locked by the locking portion 12a of the locking member 12, and the process ends. At the stage where such locking is possible, a member on the camera body side (not shown) is
c is stopped, and the part to be pushed 8c moves away from the operating locus. FIG. 1 shows a completed state of such a set operation. In this state, each blade of the front blade group is in a deployed state and completely covers the opening 1a. As described above, the blades are superimposed and stored at a position below the opening 1a.

In the above embodiment, the present invention
At the start position of the exposure operation, the front blade drive member 4 and the rear blade drive member 6 are mechanically locked by the front blade lock member 14 and the rear blade lock member 9. The case where the present invention is applied to a stop type focal plane shutter has been described. However, the present invention is not limited to such a locking type focal plane shutter. That is, an iron piece member is attached to each of the leading blade driving member 4 and the trailing blade driving member 6, and at the start position of the exposure operation, the leading blade electromagnet and the trailing blade electromagnet directly attract and hold the iron piece members. It is obvious for those skilled in the art that the present invention can be applied to a so-called direct type focal plane shutter. Further, in the above embodiment, the exposure time control circuit and the electromagnet are used. However, by using a mechanical delay mechanism, the two locking members 14 and 9 can be connected to the driving members 4 and 9 respectively.
You may remove it from 6.

[0031]

As described above, according to the present invention, at the start of photographing, the locking member can press the set member immediately after releasing the locking of the set member. Can be reliably returned to the initial position, and the exposure operation of the leading blade driving member and the trailing blade driving member can be performed without any trouble.

[Brief description of the drawings]

FIG. 1 is a plan view showing a set state of an embodiment.

FIG. 2 is a plan view showing the moment when the locking member releases the locking of the set member in the embodiment.

FIG. 3 is a plan view showing a state immediately after the locking member releases the locking of the set member in the embodiment.

FIG. 4 is a plan view showing a state of an exposure operation start position according to the embodiment.

FIG. 5 is a plan view showing a state immediately after the end of the exposure operation of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shutter base plate 1a Openings 1b, 1c, 1d, 1e Holes 1f, 1g, 1h, 1i, 1j, 1k, 1m Shaft 2, 3 Buffer member 4 Driving member for leading blade 4a, 6a Operating pin 4b, 6b, 8c, 8f, 12d Pushed portion 4c, 6c Projection portion 5 Front blade drive spring 6 Rear blade drive member 7 Rear blade drive spring 8 Set member 8a, 8b, 12b Push portion 8d Engagement portion 8e Pin 9 Rear end Locking member for blade 10 Return spring 11, 15 Stopper 12 Locking member 12a Locking portion 12c Regulator 13 Spring 14 Locking member for trailing blade

Claims (3)

[Claims] A driving member for a front blade which has a pushed portion and which is actuated by a driving spring for the front blade at the time of an exposure operation to cause the front blade group to perform an opening operation, and a pushed portion. It has a rear blade drive member that is actuated by the rear blade drive spring during the exposure operation and causes the rear blade group to perform a closing operation, and has two pushing portions and one pushed portion. The member is actuated from its initial position against its own return spring, and the two pushing portions push the pushed portions of each of the driving members separately so that each of the driving members opposes each of the driving springs. A set member which is operated to the set position and which is returned to the initial position by the return spring prior to the exposure operation of each of the driving members at the time of release, and which has a pressing portion and which is set against the return spring at the set position. When locking the member and releasing Prior to the exposure operation of each of the driving members, the member on the camera body side is actuated to release the lock, and if the set member does not immediately return even if the lock is released, the pushing portion is moved. A focal plane shutter for a camera, comprising: a locking member configured to press the pushed portion of the set member in a return operation direction. When the set member returns from the set position to the initial position, the drive member for the front blade and the drive member for the rear blade slightly follow each other by the respective drive springs, and are respectively locked at the exposure operation start position. 2. A focal plane shutter for a camera according to claim 1, wherein said focal plane shutter is locked by a member, and is unlocked sequentially during an exposure operation. 3. A driving member for the front blade and a driving member for the rear blade are provided with iron pieces, respectively. When the set member returns from the set position to the initial position, the iron pieces are respectively used for the front blade. 2. A focal plane shutter for a camera according to claim 1, wherein the focal plane shutter is attracted to the electromagnet and the electromagnet for the rear blade.