JPH09304808A - Focal-plane shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a direct type focal plane shutter capable of preventing the separation of an iron piece member from an electromagnet caused by impact force when a driving member is actuated to an exposure operation starting position. SOLUTION: A press spring 12 wound to be concentric with the driving member 6 presses the iron piece 10a of the iron piece member 10 against the iron core member 15a of the electromagnet 15, at one end of the press spring 12. After releasing is attained, a setting member 13 is actuated to return by a spring 14 and when a pushing part 13b is separated from a part to be pushed 6d, the driving member 6 is turned by a driving spring 11 and stopped at the exposure operation starting position where an attaching part 6c is abutted on the jaw part 10c of the iron piece member 10. At this time, the impact force for separating the iron piece member 10 from the electromagnet 15 is exerted, but the force of the press spring 12 is exerted so as to resist the impact force, so that influence by the impact force can be made extremely small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focal plane shutter for a camera in which a group of front blades and a group of rear blades are sequentially moved in the same direction during photographing, and a film is exposed by slits formed by the groups. About.

[0002]

2. Description of the Related Art In a recent focal plane shutter, a group of front blades and a group of rear blades are operated by respective driving members, and the start of the operation of the driving members is performed through electromagnets prepared respectively. It is controlled. The use of the electromagnet for the driving member is roughly classified into two types.
No. 139, etc., which is generally referred to as a locking type.
It is known in, for example, Japanese Patent Application Laid-Open No. 2-22636, and is generally called a direct type.

[0003] Among them, the locking type has been practiced for a long time, and the driving member is locked by a locking lever at the set position. Therefore, even if the driving member is returned to the initial position immediately after the driving member is set at the setting position, the driving member can be securely held at the setting position until the exposure operation. There is an advantage that it is not necessary to expect a time for returning to the normal state, and the risk of missing a photo opportunity can be reduced. Further, when electricity is supplied to the electromagnet at the time of photographing, there is no need to magnetically hold the drive member against the force of the strong drive spring, so-called a so-called provided for releasing the lock of the drive member by the locking lever. Since it is only necessary to attract the iron piece lever, there is an advantage that the holding force by the electromagnet does not need to be increased.

However, on the other hand, in addition to the above-mentioned locking lever and iron lever, the iron lever is moved to a position where the electromagnet can be attracted by interlocking with the setting operation of the set member, and the iron lever is moved before the exposure operation. After being attracted to the iron piece lever, a so-called hold lever or the like that retreats from the operating range of the iron piece lever is required.Moreover, since each of these levers is spring-loaded, the number of parts is large, In addition to the complicated structure, the adjustment of the operation of each part during the manufacturing process is troublesome, which is very disadvantageous in reducing the size and cost of the shutter.

On the other hand, in the direct type, an iron piece attached to a driving member is attracted by an electromagnet. Therefore, the set member cannot return to the initial position immediately after the drive member is set to the set position, and after the drive member is magnetically held by the electromagnet prior to the exposure operation, the exposure of the blade group Prior to traveling, the vehicle is returned to the initial position by its own return spring. However, although a time for the return operation is required after the release in this way, such a time can be parallel to the time required for the mirror-up and the time required for the automatic focus adjustment, etc. It is not a problem. Because of this, the direct type shutter does not require the above-mentioned various levers unlike the locking type, and is extremely advantageous in terms of space and cost. Recently, this type of shutter has increased. There is. The present invention relates to such a direct type focal plane shutter.

By the way, in such a direct type shutter, the driving member is magnetically attracted and held by the electromagnet against the strong force of the driving spring, so that the electromagnet is energized prior to the exposure operation. When this is done, the attracted surface of the iron piece member attached to the drive member is
It is required to be in a proper contact state (close contact state) with the attracting surface of the electromagnet. Therefore, in practice, when the driving member is set by the setting member, even if there are some errors in part processing and errors in assembly processing, the above-mentioned proper contact state is not affected by the error. It is devised so that it can be obtained.

One example is described in Japanese Patent Application Laid-Open No. 3-231723. According to this example, the spring (absorption spring) is interposed between the driving member (driving lever) and the iron piece member (armature). When the set member (charge lever) operates the drive member to the set position, the spring is compressed after the attracted surface of the iron piece member properly contacts the attracted surface of the electromagnet (yoke). The amount of compression absorbs the difference between individual shutters and the difference between the leading blade side and the trailing blade side so that the set operation can be performed without any trouble.

Further, in the direct type shutter, a return spring for returning to the initial position is usually applied to the setting member. Therefore, at the time of setting, the set member is actuated from the initial position by the member on the camera body side against the force of the return spring, and immediately after the release of the camera, follows the return of the member on the camera body side. Then, it returns to the initial position by the force of the return spring. However, if the camera is used for a long period of time, the contact portion between the driving member and the set member may be deformed, or if the camera is left unused for a long period of time, the contact portion may adhere to the contact portion depending on environmental conditions. May occur, and the set member may not smoothly follow the return of the member on the camera body side.

As a method for preventing such a phenomenon from occurring, it is conceivable to increase the force of the above-mentioned return spring. However, if it is too strong, on the contrary, there arises a problem that the set torque becomes large. Therefore, in order to allow the set member to follow the return of the member on the camera body side even if such a situation does not follow smoothly, the member on the camera body side does A part of is momentarily hit in the return direction.

[0010]

As described above, the direct type shutter is extremely advantageous in space and cost as compared with the locking type shutter, but is resistant to the strong force of the drive spring. Since it is necessary to magnetically hold the driving member, there remains a problem in terms of power consumption. Therefore, there is a demand for an improvement that can reliably hold the driving member by suction and consumes as little power as possible. However, when considering the improvement measures, it is not possible to simply set the attraction force by the electromagnet to a minimum value in a range exceeding the urging force of the drive spring, and the above-mentioned unique It must be structured.

That is, in the above-mentioned Japanese Patent Laid-Open No. 3-231723, when the setting member is returned to the initial position prior to the exposure operation, the setting member presses the driving member in the initial process of the returning. When released, the drive member is slightly rotated by the combined force of the spring compressed between the iron piece member and the drive member, and the drive spring, and collides with the iron piece member, causing the iron piece member to move from the electromagnet. Will give the power to separate. Therefore, the attraction force of the electromagnet with respect to the iron piece member must be sufficient to withstand the impact force generated by the above contact. Further, as described above, when returning to the initial position immediately after the release, if the set member is hit by a member on the camera body side, it must be able to withstand the vibration that occurs at that time. I will have to do it.

The present invention has been made to solve such a problem, and an object of the present invention is to provide an iron piece member until the drive member finishes operating to the exposure operation starting position prior to exposure traveling. A direct type focal plane shutter is provided in which the impact force when the drive member abuts the iron piece member at the exposure operation start position is mitigated by providing a spring member that presses the electromagnet with a predetermined biasing force. Is to provide.

[0013]

In order to achieve the above object, a focal plane shutter for a camera according to the present invention has an electromagnet which is energized at the time of release to give an attractive force, and a pushed portion. And a drive member that operates from the set position to the exposure operation start position by the drive spring at the time of release, and when the electromagnet is de-energized, further operates in the same direction by the drive spring to cause the blade group to perform exposure travel, It has a surface to be attracted to the attraction surface of the electromagnet and is attached to the drive member so as to be able to change the relative positional relationship so that the drive member can be held at the exposure operation start position by the attraction. The iron piece member and the pushing portion capable of engaging with the pushed portion, the pushing portion pushes the pushed portion at the time of setting, and the attracted surface comes into contact with the attracted surface. Et al. Actuate the drive member against the drive spring while changing the relative position to the iron piece member, and at the time of release, return to the initial position after energizing the electromagnet and operate the drive member to the exposure operation start position. And a pressing spring configured to press the attracted surface against the attracted surface with substantially the same force until at least the driving member has finished operating to the exposure operation start position. To be

In the focal plane shutter for a camera according to the present invention, preferably, the pressing spring is a torsion coil spring, and one end portion for pressing the attracted surface against the attracted surface is the above-mentioned. The iron piece member is arranged between the driving member and the iron piece member so as to bias the iron piece member. Further, in the focal plane shutter for a camera according to the present invention, preferably, a coil shape is formed on the one end portion of the pressing spring on the side opposite to the urging direction of the iron piece member so as to come into contact with the drive member. To form the compression spring portion of. Further, in the focal plane shutter for a camera according to the present invention, preferably, the pressing spring is a torsion coil spring wound concentrically with a rotation shaft of the driving member, and one end portion of the pressing coil spring is the attracted object. The surface is pressed against the suction surface so that the other end is hung on a fixing member other than the driving member.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to a first embodiment shown in FIGS. 1 to 6 and a second embodiment shown in FIGS. First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view of the present embodiment and shows a state in which the exposure traveling by the front blade group and the rear blade group is completed. FIG. 2 is a plan view for explaining the support structure of each blade group in this embodiment. FIG.
5 to FIG. 5 are plan views of the present embodiment, respectively, for explaining the operating state from the state of FIG. 1, and FIG. 6 is a sectional view taken along the line AA of FIG.

First, the configuration of this embodiment will be described mainly with reference to FIGS. 1, 2 and 6. Similar to FIGS. 4 and 5, FIG. 1 shows a part of the configuration in a cross section, and FIG. 2 shows that the shutter base plate 1 is attached to the front surface side (camera lens side) in FIG. It shows the state in which each part is removed. Further, in FIG. 1, only the drive / control configuration of the leading blade group is shown, and the drive / control configuration of the trailing blade group is not shown, but as is well known, the drive / control configuration of both blade groups may differ in shape. Since they are almost the same, they are omitted so as not to complicate the drawing. Therefore, the present invention can also be applied to the drive / control configuration of the rear blade group.
For the same reason, the drive / control configuration of the rear blade group is omitted in FIGS. 3 to 5.

The shutter base plate 1 has two arc-shaped holes 1b and 1c and a hole 1d in addition to the opening 1a for exposure. Well-known buffer members 2 and 3 made of an elastic material such as butyl rubber are fitted into the lower ends of the arc-shaped holes 1b and 1c. Further, on the front surface side of the shutter base plate 1,
The shafts 1e, 1f, 1g, 1h, 1i, 1j are erected. As shown in FIG. 6, a mounting plate (also referred to as an upper plate) 4 is fixed to the shutter base plate 1 so as to be substantially parallel to the base plate. The printed wiring board 5 is attached to the side). And, the tip ends of the shafts 1e, 1f, 1g among the above-mentioned shafts are
It is fitted in the holes formed in the mounting plate 4 and the printed wiring board 5.

The front blade drive member 6 made of synthetic resin is attached to the shaft 1e.
Is rotatably attached, and a trailing blade drive member (not shown) is similarly attached to the shaft 1f.
The leading blade drive member 6 is integrally formed with a cylindrical portion 6a that is rotatably fitted to the shaft 1e, a drive pin 6b, a mounting portion 6c, a pushed portion 6d, and a spring hook portion 6e. . Of these, the drive pin 6b penetrates the hole 1b and is fitted into a hole 7a formed in the main arm 7 of the leading blade group on the rear side of the shutter base plate 1 as is well known. The trailing blade driving member (not shown) similarly has a cylindrical portion, a driving pin, a mounting portion, a pushed portion, and a spring hook portion, of which the driving pin passes through the hole 1c and the trailing blade. It is fitted in a hole 8a formed in the main arm 8 of the group. Further, as shown in FIG. 6, a ratchet gear 9 is rotatably attached to the shaft 1e, and rotation in one direction is restricted by a well-known ratchet pawl (not shown) provided on the attachment plate 4. There is. Such a ratchet gear is similarly attached to the shaft 1f.

Further, the iron piece member 10 is attached to the attaching portion 6c. The iron piece member 10 is composed of an iron piece 10a to be attracted to an electromagnet, which will be described later, and an iron piece shaft 10b having a circular cross section. The iron piece shaft 10b is loosely fitted in a hole formed in the mounting portion 6c. There is. And the iron piece 10a
As shown in FIG. 6, the attracted surface has a rectangular shape and is integrated with one end of the iron piece shaft 10b at a substantially intermediate position.
A flange portion 10c is formed on the other end of the iron piece shaft 10b,
The iron piece member 10 does not fall off from the mounting portion 6c. Further, as can be seen from FIG. 1, the pushed portion 6d is provided on a stepped portion where the plate thickness changes on the back side of the leading blade driving member 6, and its end edge is formed in a cam shape. There is. These configurations are substantially the same for the trailing blade drive member (not shown).

As is well known, the drive spring 11 is loosely wound around the cylindrical portion 6a of the leading blade drive member 6. The drive spring 11 has one end hooked on the spring hooking portion 6e and the other end hooked on a spring hooking portion (not shown) provided on the ratchet gear 9 to urge the drive member 6 to rotate clockwise. are doing. The biasing force of the drive spring 11 can be adjusted by rotating the ratchet gear 9. The pressing spring 12 is a torsion coil spring, which is concentrically wound with the drive spring 11, one end of which is hung on the shaft 1h, and the other end of which is annular and has an iron piece shaft 10.
It is loosely wrapped around b. And this pressing spring 12
Has a biasing force in the counterclockwise direction, the flange portion 10c of the iron piece member 10 is brought into contact with the mounting portion 6c in FIG. Similarly, another driving spring and a pressing spring are also hooked on the trailing blade driving member (not shown). A shaft 1i shown in FIG. 2 is a shaft for hanging the pressing spring, and corresponds to the shaft 1h described above.

A set member 13 made of synthetic resin is rotatably attached to the shaft 1g. A cylindrical portion 13a fitted to the shaft 1g, two pushing portions 13b and 13c, a front surface side protruding portion 13d, a rear surface side protruding portion 13e, and an abutting portion 13f are integrally formed on the setting member 13. Is provided. Of these, the pushing portion 13b is the leading blade driving member 6
The pushed portion 6d and the pushed portion 13c can come into contact with the pushed portion of the rear blade drive member, and each edge is formed in a cam shape. In addition, the protrusion 13d,
The contact portion 13f is operated by a member on the camera body side. Further, the protrusion 13e is fitted in the hole 1d of the shutter base plate 1, and the rotation of the setting member 13 is restricted by the upper and lower ends of the hole 1d in the drawing.
The setting member 13 includes the shaft 1j and the protrusion 13d.
It is urged to rotate counterclockwise by a spring 14 attached to and, and FIG. 1 shows a state in which the counterclockwise rotation is restricted by the lower end of the hole 1d.

An electromagnet 15 is attached to the above-mentioned attachment plate 4 by a well-known appropriate method, as indicated by a chain line. The electromagnet 15 has a substantially U-shape and is attached so that the two magnetic pole portions (in FIG. 1, the two magnetic pole portions are vertically arranged with respect to the shutter base plate 1 as shown in FIG. 1). Core member 15 having
a and a coil bobbin 15b fitted in one of the magnetic poles, and the tip surfaces of the respective magnetic poles (the lower right end surface in FIG. 1) attract the iron piece member 10. Has become. Needless to say, another electromagnet having the same structure is attached to the above-mentioned mounting plate 4 in correspondence with the iron piece member of the trailing blade drive member.

Next, the operation of this embodiment will be described. FIG. 1 and FIG. 2 show a completed state of exposure traveling by the front blade group and the rear blade group. Therefore, in this state, the four blades forming the front blade group are superposed and stored in the lower position of the opening 1a, and the four blades forming the rear blade group are expanded to open the opening 1a. Covering. Further, as described above, the pressing piece 12 causes the iron piece member 10 to move to the collar portion 1.
0c is in contact with the mounting portion 6c. When the photographing is performed and the exposure traveling is completed, the setting operation of the shutter is performed in association with the film winding. The setting operation is performed by a member on the camera body side pressing the protrusion 13d and rotating the setting member 13 in the clockwise direction against the force of the spring 14.

When the set member 13 is rotated clockwise, the pushing portion 13b first pushes the pushed portion 6d to rotate the leading blade driving member 6 counterclockwise. Then, after the slit forming blades of the front blade group overlap with the slit forming blades of the rear blade group by a predetermined amount, the pushing portion 13c pushes the pushed portion of the rear blade driving member to rotate the driving member counterclockwise. After that, both drive members are simultaneously rotated to expand the front blade group and superimpose the rear blade group. After that, the attracted surface of the iron piece member 10 (iron piece 10a) comes into contact with the attracted surface of the electromagnet 15 (iron core member 15a), and at that time, the attracted surface of the iron piece member attached to the trailing blade drive member (not shown). The attraction surface is not yet in contact with the attraction surface of the other electromagnet.

The setting member 13 continues to rotate, and further rotates the leading blade driving member 6 in the counterclockwise direction. At this time, since the iron piece member 10 cannot move, the contact between the mounting portion 6c and the collar portion 10c is separated. Further, at this time, since the pressing spring 12 is not tensioned but the drive spring 11 is only tensioned, the amount of force required for the set operation does not sharply increase from that point as in the conventional case. Further, the torque value at this time may be set to a value that will withstand the impact described later. On the other hand, the attracted surface of the iron piece member attached to the trailing blade drive member following the leading blade drive member 6 also contacts the attracted surface of the other electromagnet, and the attachment portion of the drive member and the flange portion of the iron piece member are Come away. In this way, after the attracted surface of each iron piece member completely contacts the attracted surface of each electromagnet, the rotation of the setting member 13 is stopped and the setting operation is completed. FIG. 3 shows a completed state of such a set operation. Then, this state continues until the next shooting is performed. In addition, this FIG. 3 shows the iron piece member 1.
0 mounting components are shown without cross section.

In the state shown in FIG. 3, when the shutter button of the camera is pressed, the electromagnet 15 (coil bobbin 15b) is first energized, and the iron piece member 10 is magnetically attracted and held by the iron core member 15a. At the same time, the other electromagnet is also energized, and the iron piece member of the trailing blade drive member is attracted and held. After that, the member on the camera body side operates to release the pressing force applied to the protrusion 13d. It should be noted that the member on the camera body side is designed to move up and down in the figure like a pendulum with the spatial position on the surface side of the figure as a fulcrum.
The operation portion for the setting member 13 is provided at the tip position. Then, when the set member 13 immediately follows the force of the spring 14 due to the release of the pressing force, the operation portion does not come into contact with the contact portion 13f, but the set member 13 has some reason. If it is not immediately followed by, the abutting portion 13f remaining in the operation locus of the operating portion will be hit slightly upward. In this way, the setting member 13 rotates counterclockwise in any case.

When the setting member 13 starts rotating, first,
The pushing portion 13c of the setting member 13 separates from the pushed portion of the trailing blade drive member, and the pushing portion 13b then separates from the pushed portion 6d of the leading blade drive member 6 in the rotational direction. The state at the moment of leaving is shown in FIG. At this time, in the drawing, the mounting portion 6c of the leading blade driving member 6 is the collar portion 1 of the iron piece shaft 10b.
It is in contact with 0c. However, when manufacturing a mass-produced product, it is important to ensure that the contact state between the pushed portion 6d and the pushing portion 13b is obtained when the mounting portion 6c abuts the collar portion 10c. It's technically very difficult. Theoretically, in order to obtain such a state, the cam-shaped portion of the pushing portion 13b should be formed long or the return speed of the setting member 13 should be slowed. ,
In the former case, there is a problem that the components are large and the set stroke of the set member 13 by the member on the camera side has to be set large. In the latter case, there is a problem when the exposure traveling of the blade group is started. Will cause the problem of being slow.

Therefore, immediately after the pushing portion 13b is separated from the pushed portion 6d in the rotation direction, the mounting portion 6c is moved to the iron piece shaft 10b.
Some products come in contact with the collar portion 10c. Moreover, this abutment is performed by the force of the strong drive spring 11, and the impact force due to the abutment causes the iron piece member 10 to move to the electromagnet 15
It acts to separate from. The same thing as this can occur before the setting member 13 reaches the position shown in FIG. For example, there is a case where the cam shape of the pushing portion 13b is relatively steep and the rotation of the setting member 13 is fast. In any case, not only the above-mentioned impact force but also various vibrations due to the return of the member on the camera body side may be applied.

Therefore, according to the above-mentioned conventional example, it is necessary to give the electromagnet 15 an attractive force to withstand the impact force, but in this embodiment, the pressing spring 12 contacts the iron piece member 10 with the electromagnet 15. Since it is biased in the direction, it is possible to remarkably reduce the influence of the impact force compared to the case of the conventional example, and it is possible to make the attraction by the electromagnet 15 more reliable. On the other hand, the attraction force is set weaker accordingly. It becomes possible. Moreover, when setting the drive spring, it is not necessary to consider the force of the spring that is interposed between the drive member and the iron piece member and acts as the biasing force of the drive member as in the conventional case. Only the force of 11 needs to be considered. Therefore, it is possible to save power consumption. Then, in this way, the mounting portion 6c of the leading blade drive member 6 comes into contact with the flange portion 10c of the iron piece shaft 10b as shown in FIG.
This state is the standby state for the exposure operation of the leading blade drive member 6. On the other hand, at this stage, the trailing blade driving unit (not shown) is also in such a standby state, and then the setting member 13 returns to the initial position and stops. This state is shown in FIG.

After the setting member 13 returns to the initial position,
When the power supply to the electromagnet 15 for the leading blade is cut off by the signal from the control circuit, the leading blade driving member 6 is rapidly rotated clockwise by the driving force of the strong driving spring 11.
Therefore, the leading blade group which has been expanded and covered the opening 1a is actuated by the drive pin 6b, opens the opening 1a while deepening the mutual overlapping of the blades, and travels downward. Finally, the drive pin 6b collides with the buffer member 2 to absorb the bound and stop.
When a predetermined time elapses after the leading blade driving member 6 starts exposure traveling in this way, the power supply to the electromagnet for the trailing blade is cut off. As a result, the trailing blade drive member is rotated in the clockwise direction, and the trailing blade group stored in the position above the opening 1a is expanded to close the opening 1a. Then, finally, the drive pin collides with the cushioning member 3 to absorb the bound of the rear blade group and stop. FIG. 1 shows the state at that time.

In this embodiment, the pressing spring 12 is used.
Is a torsion coil spring, and is arranged concentrically with the drive spring 11, that is, concentrically with the rotary shaft 1e of the drive member 6,
This is so that the urging force on the iron piece member 10 acts on the electromagnet 15 in the contact direction, that is, on the vertical direction with respect to the attracting surface. The attracting surface is brought into contact with the attracting surface of the electromagnet 15 in a state of being correctly opposed to prevent abrasion between the contact surfaces, and even if the above-mentioned impact force is unevenly applied at the time of release, it is possible to respond to them on average. To do so. However, the present invention is not limited to such an arrangement. In addition, in the present embodiment, the end portion of the annular pressing spring 12 pushes the iron piece 10a of the iron piece member 10, but the end portion may push the brim portion 10c. In that case, various ways of attaching the end portion to the collar portion 10c are conceivable, and accordingly, the shape of the end portion is not annular but various shapes are conceivable.

Next, a second embodiment of the present invention will be described with reference to FIGS.
This will be described using 1. However, the configuration of the present embodiment is almost the same as that of the first embodiment, and only the shape of the pressing spring 12 is substantially different, and therefore the reference numerals of the respective parts and parts are the same as those of the first embodiment. The reference numerals will be used, and only different points will be described to avoid duplication. Also, since the operation is basically the same, a brief description will be given to avoid duplication.

As described above, the structure of this embodiment is different from that of the first embodiment in that the shape of the pressing spring 12 is substantially different. As a result, the shape of the leading blade drive member 6 is also partially changed, but this is merely a consideration for the assembling of the pressing spring 12 and has no other meaning. In the case of the first embodiment, the end portion of the pressing spring 12 that presses the iron piece member 10 against the electromagnet 15 has an annular shape, whereas in the present embodiment, the entire shape of the end portion has a small diameter. From the portion to the large diameter portion, it is wound so as to form a truncated cone, and only this end portion constitutes the compression spring. The small diameter portion contacts the iron piece 10a of the iron piece member 10, and the large diameter portion contacts the inner peripheral wall of the hole formed in the mounting portion 6c.

Next, the operation of this embodiment will be briefly described with reference to the drawings. Further, in principle, description of each member on the rear blade driving / control side will be omitted. FIG. 7 shows a state where the exposure traveling is completed. In this state, the collar portion 1 of the iron piece member 10 is urged by the urging force of the pressing spring 12.
0c is in contact with the mounting portion 6c. The member on the camera body side is the set member 13 in conjunction with the film winding.
When is rotated clockwise, the pushing portion 13b moves the pushed portion 6
By pressing d, the leading blade drive member 6 is rotated counterclockwise, and the attracted surface of the iron piece member 10 (iron piece 10a) eventually becomes
It contacts the attracting surface of the electromagnet 15 (iron core member 15a). This contact is made by the shape of the end portion of the pressing spring 12 of the iron piece member 10 with respect to the attachment portion 6c regardless of the posture up to that point and any vibration. Since the relative positional relationship is not changed, the attracting surface and the attracted surface are in a substantially ideal facing relationship.

The setting member 13 continues to rotate, further rotating the leading blade driving member 6 in the counterclockwise direction. At this time, since the iron piece member 10 cannot move, the contact between the mounting portion 6c and the flange portion 10c is separated, and the frustoconical spring portion is compressed at the end portion of the pressing spring 12. After that, the rotation of the setting member 13 is stopped, and the setting operation is completed in the state of FIG. The electromagnet 15 (coil bobbin 15b) is energized by the release of the camera, and the iron piece member 10
When the member on the camera body side is actuated after being sucked and held, the set member 13 starts to rotate counterclockwise following the operation. FIG. 9 shows a state in which the pushing portion 13b of the setting member 13 is separated from the pushed portion 6d of the leading blade driving member 6 in the rotation direction.

In this way, the mounting portion 6c may contact the flange portion 10c of the iron piece shaft 10b immediately after the pushing portion 13b is separated from the pushed portion 6d in the rotational direction. In the case of the example, the force of the drive spring 11 and the restoring force of the above-mentioned frustoconical spring portion act on this contact. However, in the present embodiment, as in the case of the first embodiment, the pressing spring 12 is biased in the direction of bringing the iron piece member 10 into contact with the electromagnet 15, so that it is more than in the case of the conventional example. The influence of the impact force can be mitigated, and the iron piece member 10 can be more securely held by suction. On the other hand, on the other hand, the suction force can be set weakly, and power consumption can be saved. After that, the setting member 13 returns to the initial position and stops. This state is shown in FIG. The subsequent exposure operation is the same as in the first embodiment, and the completed state is as shown in FIG.

As described above, in this embodiment, the effect of absorbing the impact force is inferior to that of the first embodiment by the amount of the frustoconical spring portion formed in the presser spring 12, but the conventional example does not. It's much better than anything. Further, in the present embodiment, even when the driving member 6 receives a much larger impact than the above impact at the time of completion of the exposure operation, the mounting portion 6c and the iron piece member 10 are relatively opposed to each other by the spring shape of the truncated cone. Since the relationship is not changed, there is an advantage that the iron piece member 10 can be always brought into contact with the electromagnet under the same ideal condition (see Japanese Utility Model Publication No. 6-26898), and in that respect, in the case of the first embodiment. Is more advantageous than. Moreover, it is excellent in that the effect described in Japanese Utility Model Publication No. 6-26898 and the effect according to the present invention can be obtained by one spring component. The effects of the present invention can be obtained even if the compression spring portion is formed by winding the frustoconical spring portion into a conical shape, a cylindrical shape, or the like.

[0038]

As described above, in the present invention, in the direct type focal plane shutter, the iron piece member is fixed to the electromagnet until the driving member finishes moving to the exposure operation starting position prior to the exposure traveling. Since the spring member that is pressed by the urging force is provided, even if the drive member reaches the exposure operation start position and contacts the iron piece member, the urging force causes the iron piece member to move away from the electromagnet. The force is relieved, and the adsorption holding of the iron piece member by the electromagnet can be reliably maintained. It also makes it possible to save power consumption.

[Brief description of drawings]

FIG. 1 is a plan view of a first embodiment, showing an exposure traveling completed state of each blade group.

FIG. 2 is a plan view for explaining a support structure of each blade group in the first embodiment.

FIG. 3 is a plan view of the first embodiment, showing a set operation completion state of the set member.

FIG. 4 is a plan view of the first embodiment, showing a state in which the pushing portion of the setting member is about to separate from the pushed portion of the driving member after release.

FIG. 5 is a plan view of the first embodiment, showing a state when the setting member returns to the initial position.

6 is a cross-sectional view taken along the line AA in FIG.

FIG. 7 is a plan view of the second embodiment, showing an exposure traveling completed state of each blade group.

FIG. 8 is a plan view of the second embodiment showing a set operation completion state of the set member.

FIG. 9 is a plan view of the second embodiment, showing a state where the pushing portion of the setting member is about to separate from the pushed portion of the driving member after release.

FIG. 10 is a plan view of the second embodiment, showing a state when the setting member returns to the initial position.

11 is a sectional view taken along line BB in FIG. 10;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shutter base plate 6 Leading blade drive member 6b Drive pin 6c Mounting part 6d Pushed part 10 Iron piece member 10a Iron piece 10b Iron piece shaft 10c Collar part 11 Drive spring 12 Holding spring 13 Set member 13b, 13c Pushing part 15 Electromagnet 15a Iron core Element

Claims (4)

[Claims] 1. An electromagnet which is energized at release to give an attraction force, and a driven part which is operated from a set position to an exposure operation start position by a drive spring at the time of release to de-energize the electromagnet. Then, the drive member is further operated in the same direction by the drive spring to cause the blade group to perform exposure travel, and the attracted surface to be attracted to the attracting surface of the electromagnet has a relative positional relationship with the drive member. A set that includes an iron piece member that is attached so as to be changeable so that the driving member can be held at the exposure operation start position by the suction, and a pushing portion that can engage with the pushed portion. Occasionally, the pushing portion pushes the pushed portion, and after the attracted surface comes into contact with the attracted surface, the driving member is actuated against the drive spring while changing the relative position to the iron piece member. At release A set member that returns to the initial position after energizing the electromagnet and enables the drive member to operate to the exposure operation start position, and the attracted surface until at least the drive member has finished operating to the exposure operation start position. And a pressing spring configured to press the suction surface against the suction surface with substantially the same force. 2. The pressing spring is a torsion coil spring, and one end portion for pressing the attracted surface against the attracted surface is disposed between the drive member and the iron piece member. The focal plane shutter according to claim 1, wherein the member is biased. 3. A coil-shaped compression spring portion is formed at the one end of the pressing spring on the side opposite to the urging direction of the iron piece member so as to come into contact with the drive member. The focal plane shutter according to claim 2. 4. The pressing spring is a torsion coil spring wound concentrically with the rotary shaft of the drive member, one end of which presses the attracted surface against the attracted surface, and the other. The focal plane shutter according to any one of claims 1 to 3, wherein an end portion is hung on a fixing member other than the driving member.