JPH10333208A - Camera shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shutter suitable for attaining the high speed of an exposure time and stabilizing the actuation of shutter blades, in a type of shutter for actuating one linkage member in a direction where it crosses an optical axis, so as to reciprocate three or more shutter blades in a circular aperture surface. SOLUTION: The actuating pin 6a of an opening/closing member 6 directly connected to a motor 4 is in contact with the recessed part 10a of an annular linkage member 10 and a spring 17 pushes the linkage member 10 upward. When the actuating pin 6a is moved upward by the motor 4, at the time of executing an exposure operation, the linkage member 10 is actuated upward to turn the shutter blades 11, 12 and 13 of an opening blade group and open an aperture 1b. When the actuating pin 6a is moved downward by the motor 4, at the time of executing a setting operation, the aperture 1b is covered. As constitution for actuating a closing blade group consisting of three blades, constitution similar to the above-mentioned one is adopted. Three blades are arranged in a piled up state in an optical axial direction by using a partition as a boundary, close the aperture, at the time of executing the exposure operation and retreat from the aperture, at the time of executing the setting operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera shutter in which a plurality of shutter blades open and close a circular exposure opening when a film is exposed.

[0002]

2. Description of the Related Art A shutter of this type is called a lens shutter. During exposure operation, a plurality of shutter blades open an opening for exposure from the center of an optical axis. It is designed to close toward the center of the optical axis. During the operation, it is ideal that the plurality of shutter blades can always maintain a substantially circular opening shape. Therefore, in the past, a plurality of shutter blades were arranged at equal intervals around an exposure opening, and they were operated by a drive ring that reciprocates around an optical axis. In addition, the rotation of the drive ring is performed only by the spring force. However, such a shutter has a high processing cost because the drive ring is disposed in a groove formed over substantially the entire circumference with respect to the shutter base plate surface.
Regardless of the plane friction resistance, extremely large peripheral friction resistance was generated, and there was naturally a limit to speeding up.

[0003] After that, with the advancement of film technology and lens technology, the above-mentioned opening shape during operation has been allowed to be somewhat broken, and the cost reduction has been emphasized. It has become. for that reason,
Those using a drive ring have disappeared, except for the large shutters used in professional cameras, and instead have been replaced by two-bladed shutters that perform a reciprocating operation relative to each other. However, since the shape of the opening during operation cannot be largely destroyed, it is designed so that a shape close to an ideal is obtained as much as possible as a two-blade shutter. Was decided. However, since then, with the advent of the IX240 cartridge film (APS film), demands for miniaturization and motorization have increased, not to mention the cost reduction, but especially the requirements for miniaturization have increased. .

Incidentally, the inner diameter of the lens shutter is, of course, determined by the aperture of the lens. Therefore, reducing the size of the lens shutter does not mean simply reducing the overall size. This is how to make the mechanism arrangement part compact. This is nothing but how to reduce the planar accommodation space of the shutter blades when the exposure opening is fully opened. However, in the two-bladed shutter described above, the size of the shutter has already been reduced as much as possible. If the size is to be further reduced, the opening shape during operation cannot be maintained in an allowable range. Would.

Therefore, in order to further reduce the size, it is necessary to use three or more shutter blades to reduce the plane area per one and to arrange them at substantially equal intervals around the optical axis. Although it is necessary, a drive ring as in the related art cannot be used for the reasons described above and also from the viewpoint of cost. Therefore, an operating member called a link member made of a thin plate material that does not generate a frictional force on the peripheral surface is provided, and three or more shutter blades are connected to the operating member to open and close the opening for exposure. A shutter has been proposed by the present applicant and is known from Japanese Utility Model Laid-Open No. 7-5131, Japanese Patent Laid-Open No. 7-13218, and the like.

On the other hand, a coil spring has long been used as a drive source of the shutter. However, recently, from the viewpoint that a shutter driving mechanism does not have to be set for each photographing, a motor using a motor as a driving source has increased. Each of the shutters described in the above two publications uses a motor as a drive source. As a type of motor, a stepping motor (STM) was initially considered because a large driving force could be obtained. However, the stepping motor is not easy to miniaturize.
There is a problem that the size is increased when the size is reduced. Therefore, at present, attention has been paid to the use of a motor called a moving magnet type motor which is lower in cost than a stepping motor and is easy to cope with miniaturization.

This moving magnet type motor is characterized in that a rotor of a permanent magnet (usually two poles) is reciprocated within a predetermined angle range depending on the direction of current supply to the coil. In comparison with the above, there is a problem that it is suitable for size reduction and cost reduction, but it is difficult to obtain a large driving force. Of the above two publications,
The moving magnet type motor is used in the shutter described in Japanese Patent Application Laid-Open No. 7-13218. The present invention relates to a camera shutter in which a link member connecting three or more shutter blades is reciprocated by various driving sources.

[0008]

By the way, in the normal case, the lens shutter exposes the film by reciprocating the shutter blades, but temporarily stops when the shutter blades shift from the opening operation to the closing operation. There is a moment (called a dead point), and the closing operation cannot be performed quickly immediately. When the exposure time is relatively long, it is necessary to stop the shutter blade in the fully opened state, but in order to prevent the shutter blade from bouncing and temporarily covering a part of the opening at the time of the stop, the shutter blade must be stopped. The position is preset at a position past the fully open position. Therefore, after the shutter blade fully opens the opening for exposure, it is not possible to immediately start closing the opening. From this, it can be said that a normal lens shutter basically has a configuration in which it is difficult to obtain a high-speed exposure time. Of course, the shutter described in the above publication also has such a problem.

In particular, when a moving magnet type motor is used as a driving source, such a problem becomes more remarkable. As described above, the moving magnet type motor cannot be said to have a large driving force, and also has difficulty in starting up as compared with the pulse motor. Therefore, it takes a long time from the start of energization until a predetermined driving force is obtained, and the driving force is easily affected by a slight variation in load or a change in supply voltage. As described above, in a shutter that operates three or more shutter blades, the load is increased as compared with a shutter having a two-blade configuration, and it is extremely difficult to stably obtain a high speed.

However, in the case of a shutter using three or more blades, as described above, the opening shape can be maintained at a suitable shape centered on the optical axis during operation. In that respect, the performance is superior to that of the two-bladed shutter. for that reason,
In order to further improve the performance as a shutter, it is desired to obtain a higher speed than ever. Further, since this type of shutter has an excellent opening shape during operation, it is often used for a relatively high-end camera having a large lens aperture, and in some cases, it can be used instead of the above-described one using a drive ring. As a result, there is a possibility that it will be used in professional cameras. However, as the lens diameter increases, the size of the shutter blades increases and the load increases, which causes a problem that it is difficult to obtain a high speed. From such a viewpoint, there is a strong desire to stably obtain a high speed.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide an annular or arc-shaped link member arranged so as to surround an exposure opening. A shutter configured to reciprocate three or more shutter blades pivotally mounted at predetermined intervals around the opening by reciprocating in a direction transverse to the optical axis, and stabilizing high speed. It is an object of the present invention to provide a camera shutter which can be obtained by using a camera.

[0012]

In order to achieve the above object, a camera shutter according to the present invention comprises two shutter base plates each having a circular opening centered on the optical axis, and the two shutter base plates. And a partition plate forming a first blade chamber and a second blade chamber, each of which is composed of three or more blades, and is separately disposed in the first blade chamber and the second blade chamber. Each blade has a fulcrum portion and a moving point portion, and at the fulcrum portion, can be reciprocated between a position where the opening is opened and a position where the opening is closed. A first shutter blade group and a second shutter blade group, one of which opens and the other closes, and are arranged so as to surround the opening in the first and second blade chambers, each of which has an annular or arcuate shape. And the moving point of each blade A first link member and a second link member rotatably connected and reciprocating in a direction crossing the optical axis to reciprocate the blades at respective fulcrum portions, and provided outside the blade chamber. And a first drive means and a second drive means, each of which is capable of reciprocating operation and which enables reciprocal operation of the first link member and the second link member in conjunction with the reciprocating operation. In the camera shutter according to the present invention, preferably, the first driving unit and the second driving unit each include:
The motor includes a reciprocally rotatable motor and an opening / closing member that is reciprocated by the motor. During the exposure operation, the first shutter blade group performs an opening operation, and the second shutter blade group performs a closing operation. The first link member is urged by a spring in a direction to open the first shutter blade group so as to be in contact with one of the opening and closing members. In that case, preferably,
The motor constituting the first drive means is a moving magnet type motor, and in the set state, the magnetic force of the permanent magnet rotor overcomes the urging force of the spring, and the first link member is moved to the set position. To be held. Further, in the camera shutter of the present invention, preferably, the first driving means and the second driving means are each constituted by a reciprocally rotatable motor and an opening / closing member reciprocally operated by the motor, The opening and closing members are connected to the first link member and the second link member by pin and slot. In this case, preferably, each of the motors is operated to only one of them only at the time of the exposure operation, and the first shutter blade group and the second shutter blade group perform the opening operation and the closing operation at the time of the exposure operation. Alternately. Or, in that case, at the time of the exposure operation, the first shutter blade group performs the opening operation, the second shutter blade group performs the closing operation, and at least the first link member of the motor is connected. The motor to be operated is a moving magnet type motor, and the first link member is biased by a spring in a direction to open the first shutter blade group. Further, in the camera shutter of the present invention, preferably, at the time of an exposure operation, the first shutter blade group performs an opening operation, and the second shutter blade group performs a closing operation. At least one of the first driving means and the second driving means is an opening / closing member connected to the link member by a pin / slot connection and imparted with a rotation behavior in one direction by a spring. At times, the spring is rotated by the spring by being released by the electromagnet, and at the time of setting, it is turned to a contact position with the electromagnet against the spring by a set member. In that case, preferably, the connection relationship between the opening / closing member and the link member is such that the link member is engaged with the opening / closing member by being urged by another spring, and the opening / closing member is released to the electromagnet. When it turns, it operates so as to follow it.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to a first embodiment shown in FIGS. 1 to 5, a second embodiment shown in FIG.
This will be described with reference to the third embodiment shown in FIG. FIG. 1 shows the first
It is a sectional view required for understanding the skeleton of the whole composition of an example. 2 and 3 show the setting state of the shutter. FIG. 2 is a plan view of the partition plate in FIG. 1 as viewed from the left side, and FIG. 3 is a view of the partition plate in the right direction. FIG. FIG. 4 is a plan view as viewed in the same manner as FIG. 2, and shows a fully opened state of the shutter. FIG.
FIG. 4 is a plan view as viewed in the same manner as FIG. 3 and shows a state after the exposure operation is completed and before setting. FIG. 6 and FIG. 7 are plan views of main parts showing a state after the shutter button is pressed and immediately before the exposure operation is started, respectively.

First, the configuration of the first embodiment will be described with reference to FIGS. As can be seen from FIG. 1, in the present embodiment, two blade chambers are formed by partitioning the two shutter base plates 1 and 2 with the partition plate 3. The shutter base plates 1 and 2 are made of synthetic resin, and as can be seen from FIGS. 2 and 3, four pedestals 1a and 2a having holes are provided on the blade chamber side, respectively. The shutter base plates 1 and 2 and the partition plate 3 are mounted by sandwiching the partition plate 3 between these pedestals 1a and 2a and screwing screws (not shown) into holes of the pedestals 1a and 2a. Therefore,
Although not shown, it goes without saying that the mounting hole is formed in the partition plate 3. In addition, other than this, actually, an attachment portion to the camera body is formed, but these are not shown. Further, the shutter base plates 1 and 2 and the partition plate 3 are formed with exposure openings 1b, 2b and 3a having a circular shape centered on the optical axis.

On the outer wall surfaces of the shutter base plates 1 and 2,
Moving magnet type motors 4 and 5 are attached to operate the opening blade group and the closing blade group separately arranged in the two blade chambers. As described above, this type of motor is well known, but its configuration will be briefly described with reference to the cross-sectional view of FIG. The rotors 4a and 5a are made of permanent magnets and are normally magnetized to two poles. The rotating shafts of the rotors 4a and 5a are made of synthetic resin and are integrally formed with the opening and closing members 6 and 7. Rotors 4a, 5a
Are supported by upper frames 4b and 5b and lower frames 4c and 5c, and coils 4d and 5d are wound so as to bundle them. In addition, cylindrical yokes 4e, 5e are attached around the cup-shaped upper frames 4b, 5b. The motors 4 and 5 are attached to the shutter base plates 1 and 2 by two screws 8, 8, 9 and 9, respectively. The operating pins 6a, 7a of the opening / closing members 6, 7 are connected to the holes 1c, 2c of the shutter base plates 1, 2.
Penetrating through each of the blade chambers.

A blade chamber of a group of opening blades is formed between the shutter base plate 1 and the partition wall 3. As can be seen from FIG. 2, an annular link member 10 is provided in the blade chamber.
And three shutter blades 11, 12, and 13, which are arranged in the order of the link member 10, the shutter blade 11, the shutter blade 12, and the shutter blade 13 from the paper surface toward the near side. . Of these, link member 1
0, a concave portion 10a, an engaging portion 10b, and three projecting portions 10
c, 10d, 10e, three long holes 10f, 10g, 1
0h is formed. The recess 10 a contacts the operating pin 6 a of the opening / closing member 6, and
Reference numerals 0c, 10d, and 10e are slidably mounted on shelf-shaped receiving portions 1d, 1e, and 1f formed on the shutter base plate 1 with a large thickness, respectively. Also, holes 10f, 10g, 10
h denotes shafts 1g and 1 erected on the shutter base plate 1, respectively.
h, 1i.

The shutter blades 11, 12, and 13 are respectively
These holes are fitted to the shafts 1g, 1h, and 1i, and can reciprocate around the fitted portions. Further, each of the shutter blades 11, 12, and 13 respectively
It is attached to the link member 10 by connecting shafts 14, 15, and 16. Each of the connecting shafts 14, 15, 16 is a rivet component, is inserted from the back side of the link member 10 in FIG. 2, and is caulked on the surface side of each of the shutter blades 11, 12, and 13. Therefore, the space between the link member 10 and each of the connection shafts 14, 15, 16 is movable, and the connection shaft 1
Reference numerals 4, 15, and 16 are moving points of the shutter blades 11, 12, and 13. The shutter blade 13 has a projection 13a formed at the tip thereof. This is to block the optical path of the photoreflector at the initial stage of the opening operation. However, since the configuration and function of such a detection mechanism are well known, the illustration of the photoreflector is omitted, and the detailed functional description is omitted. Omitted.

A shaft 1j is provided upright on the outer wall surface of the shutter base plate 1 to which the moving magnet type motor 4 is attached, and a spring 17 is wound around the shaft 1j. One end of the spring 17 is hooked on a spring hook 1k, and the other end is bent and inserted into the blade chamber from the hole 1m, and is hooked on the engaging portion 10b of the link member 10. Therefore, FIG.
In, the link member 10 is urged by a spring 17 to operate upward. In the set state shown in FIG. 2, no current is supplied to the coil 4d of the moving magnet type motor 4. However, this motor 4
A magnetic member is disposed close to the rotor 4a at an appropriate place, and a clockwise rotating force acts on the rotor 4a by a magnetic force acting between the two. Then, the force is larger than the urging force of the spring 17, and the link member 10 is pushed downward by the operating pin 6a.
The operation pin 6a stops when it comes into contact with the end face of the hole 1c.

On the other hand, a blade chamber of a closing blade group is formed between the shutter base plate 2 and the partition wall 3. As can be seen from FIG. 3, the configuration inside this blade chamber is quite similar to the configuration inside the blade chamber of the opening blade group. Therefore, a brief description will be given. An annular link member 18 and three shutter blades 19, 20, and 21 are also arranged in the blade chamber. The order of the arrangement is such that the link member 18, the shutter blade 19, Shutter blade 2
0, shutter blades 21. The link member 18 has a slot 18a and three long holes 18b, 18c,
18d and three overhangs 18e, 18f, 18g. The slot 18a is fitted to the operating pin 7a of the opening / closing member 7, and the holes 18b, 18
c and 18d are shafts 2g and 2 erected on the shutter base plate 2, respectively.
h, 2i, which are overhangs 18e, 18f, 18
g denotes receiving portions 2d, 2e, 2 formed on the shutter base plate 2.
f is slidable.

The shutter blades 19, 20, 21 are respectively
These holes are fitted to the shafts 2g, 2h, and 2i, and can reciprocate around the fulcrums. Each of the shutter blades 19, 20, and 21 has a connecting shaft 22, 23,
24, the connecting shafts 22, 23, 24 are connected to the shutter blades 19,
20 and 21 are moving point portions. Further, the shutter blade 21 has a projection 21a formed at the tip thereof, but this is merely a common component with the shutter blade 13 and has no particular meaning. The moving magnet type motor 5 is also provided with a magnetic member (not shown). Accordingly, in FIG. 3, the operation pin 7a of the opening / closing member 7 pushes the link member 18 downward, but stops because the operation pin 7a contacts the end face of the hole 2c.

Next, the operation of this embodiment will be described. 2 and 3 show the set state. At this time, as shown in FIG. 2, the link member 10 is pushed down on the end face of the recess 10 a by the operating pin 6 a and is operated downward against the spring 17. Therefore, each blade 11, 1 of the open blade group
Reference numerals 2 and 13 are rotated clockwise about shafts 1g, 1h and 1i, which are fulcrum portions, and close the opening 1b. On the other hand, as shown in FIG.
Is operated downward. Therefore, each of the blades 18, 19, and 20 of the closed blade group is connected to a shaft 2 serving as a fulcrum.
It is rotated clockwise around i, 2h, and 2g, and completely retreats from the opening 1b.

When the shutter button is pressed in this state, the power switch is first closed, and the photo reflector (not shown) attached to the shutter base plate 1 is turned on. As a result, the light emitted from the light emitting unit into the blade chamber is reflected by a reflection sheet (not shown) attached to the partition plate 3 and enters the light receiving unit. After such a preparation state, when the coil 4d of the moving magnet type motor 4 is energized in the forward direction, the rotor 4d
The opening / closing member 6 integrated with a rotates counterclockwise in FIG. 2, and the operating pin 6a operates upward.

The moving magnet type motor is inferior in startability to the pulse motor, has a slow initial operation, and is easily affected by load conditions and supply voltage. Therefore, it is difficult to shorten the exposure time, and it is difficult to stabilize the operation. However, in the case of the present embodiment, since the spring 17 urges the link member 10, the link member 10 not only follows the operation of the operation pin 6a but also positively pushes the operation pin 6a. Like that. Therefore, at the beginning of the operation, the link member 10 is
The operation is faster and more stable than when only the motor is used.

As described above, when the link member 10 starts operating upward, the shutter blades 11, 1 of the opening blade group are opened.
2 and 13 also start to rotate counterclockwise around the axes 1h, 1g and 1i, respectively. When the projection 13a of the shutter blade 13 interrupts the optical path of the photoreflector before the pinhole state, the output signal starts counting the time by the exposure time control circuit. Thereafter, the shutter blades 11, 12, and 13 bring the opening 1b into a pinhole state and open the opening around the optical axis, but continue slightly after opening the opening 1b, The operation pin 6a stops when it comes into contact with the upper end surface of the hole 1c. The state at that time is shown in FIG.

After that, when the exposure time control circuit finishes the predetermined counting, the coil 5d of the other moving magnet type motor 5 is energized in the forward direction in accordance with the output signal. Therefore, the opening / closing member 7 integral with the rotor 5a rotates counterclockwise in FIG. 3, and pushes the end face of the slot 18a by the operating pin 7a to operate the link member 18 upward. Therefore, the shutter blades 19, 20, and 21 of the closed blade group rotate counterclockwise about the axes 2h, 2g, and 2i. Then, after the shutter blades 19, 20, and 21 close the opening 2b, the operating pin 7 is closed.
Stops when a contacts the upper end surface of the hole 2c.
The state at that time is shown in FIG.

In the above description, the case where the opening blade group stops the opening operation and then the closing blade group starts the closing operation has been described. However, according to the present embodiment, the opening blade group stops. Immediately before, or in some cases, immediately before the opening blade group fully opens the opening 1b, the closing blade group can start the closing operation. As a result, the opening can be closed almost at the same time as the opening is fully opened, so that a high-speed exposure time can be obtained. Further, if necessary, the opening can be closed before the opening is fully opened.

Thus, when the exposure operation is completed,
Next, a set operation is performed. In this case, first, the coil 4d of the moving magnet type motor 4 is energized in a direction opposite to the previous direction. Therefore, the opening / closing member 6 rotates clockwise in FIG. 4 and pushes the concave portion 10a of the link member 10 by the operating pin 6a. Then, the link member 10 operates downward against the urging force of the spring 17 to move the shutter blades 11, 12, and 13 of the opening blade group to the shafts 1h and 1h.
Rotate clockwise in g and 1i to cover the opening 1b. This operation is stopped when the operating pin 6a comes into contact with the lower end surface of the hole 1c, and the state shown in FIG. 2 is obtained.

Thereafter, the coil 5d of the other moving magnet type motor 5 is also energized in the direction opposite to the above. As a result, the opening / closing member 7 rotates clockwise in FIG. 5 and pushes the end face of the slot 18a by the operating pin 7a to operate the link member 18 downward. As a result, the shutter blades 19, 20, and 21 of the closing blade group
Rotates clockwise about the axes 2h, 2g, and 2i, and the opening 2
Retreat from b. Thereafter, the operation pin 7a stops when the lower end surface of the hole 2c comes into contact with the operation pin 7a, and a state shown in FIG. 3 is obtained. Finally, the energization to the coils 4d and 5d is cut off, but as described above, the magnetic force acting between the rotors 4a and 5a and a magnetic member (not shown) causes the next photographing to be performed. This state is maintained.

As described above, according to this embodiment, since the exposure operation is performed by the opening blade group and the closing blade group, the exposure time can be shortened, and in the opening operation of the shutter, the link member 10 and the shutter blade are used. Since the motors 11, 12, and 13 do not become loads on the motor, but rather are pushed in the rotational direction by the urging force of the spring 17 applied to the link member 10, the startability, which is a weak point of the moving magnet type motor, is greatly improved. The rising characteristics of the shutter blades 11, 12, and 13 are improved, and the operation is stabilized. Therefore, exposure control in a high-speed region of the shutter speed can be stably obtained, and light emission control of a flash which is usually performed in synchronization with an opening operation is also simplified.

In this embodiment, the link member 1
Although the motors 0 and 18 are driven by the moving magnet type motors 4 and 5, a stepping motor may be used as a driving source. In that case, one may be a moving magnet type motor and the other may be a stepping motor. Further, in the present embodiment, the opening / closing members 6, 7 are integrally formed with the rotors 4a, 5a, but one or both of them may be formed separately as is well known. Absent.

The connection between the opening / closing member 6 and the link member 10 may be a so-called pin / slot connection like the connection between the opening / closing member 7 and the link member 18. In this case, a slot is formed in the opening / closing member 6, and the link member 1 is formed.
0 may be provided with a pin. However, in this case, since the link member 10 and the shutter blades 11, 12, and 13 become loads of the motor 4, the performance is inferior to that of the embodiment. It is possible to obtain the effect of When the link between the opening / closing member 6 and the link member 10 is also formed by the pin / slot connection, as described above, the shutter blades 11, 12, and
13 and the shutter blades 19, 20, and 21 are not limited to the closed blade group. The shutter blade 1 is not used for the next photographing without performing the setting operation from the state of FIGS.
It is possible to operate the shutter blades 9, 20, 21 as a group of open blades in the state of FIG. 3 and to operate the shutter blades 11, 12, 13 as a group of closed blades in the state of FIG.
On the other hand, the connection relationship between the opening / closing member 7 and the link member 18 may be configured like the connection relationship between the opening / closing member 6 and the link member 10 in the embodiment.

Further, in this embodiment, the link member 1
Although 0 has a ring shape, the present invention is not limited to such a shape. For example, in the present embodiment, a connection portion with the shutter blade 11 and a connection portion with the shutter blade 12 may be left, and an arc shape may be formed with a gap between them. In this case, the shape is such that the opening 1b is surrounded by about 240 °. This means that the link member 1
The same applies to the shape 8. Furthermore, in the present embodiment, one shutter blade group is composed of three blades. However, four or more shutter blades may be used if necessary. If the number is four, the link members 10 and 18 may have a shape surrounding the opening 1b by about 270 °. However, this is the case where the shutter blades are arranged at equal intervals around the opening, and even if three shutter blades are used, it is necessary to sacrifice some compactness. , 240 ° or less.

Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment differs from the first embodiment only in part of the configuration, and FIG. 6 shows only those parts necessary for understanding the different points. Therefore, the same members and the same parts as those in the configuration of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. FIG.
Shows a state in which the shutter blades 11, 12, and 13 completely close the opening 1b, but differs from the set state in the description of the first embodiment because the driving means is different from that of the first embodiment. In state. This will be described in detail below.

The feature of this embodiment is that the link members 10 and 18 in the first embodiment are driven only by spring force without being driven by a motor. That is,
An electromagnet 25 is attached to the outer wall surface of the shutter base plate 1 by an appropriate means. And this electromagnet 25
Is composed of an iron core member 25a and a coil 25b. An opening / closing member 26 is rotatably attached to a shaft 1n provided upright on the shutter base plate 1, and is urged by a spring 27 to rotate counterclockwise. The opening / closing member 26 is provided with an iron piece 26a and an operating pin 26b, and the iron piece 26a is an iron core member 25a of the electromagnet 25.
So that it can be adsorbed. In addition, the operating pin 26
b penetrates the hole 1c and fits into a slot 10i formed in the link member 10 in the blade chamber. In this embodiment, the spring 17 of the first embodiment is not provided.

Further, a set ring 28 is disposed on the outer wall surface of the shutter base plate 1 so as to be rotatable about the optical axis. The operating surface of the set ring 28 is
Is closer to the outer wall surface of the shutter base plate 1 than the working surface of the shutter ring, and the cam surface 28a of the set ring 28 is
Can be contacted. Although not shown, a configuration similar to the configuration of the drive system including the electromagnet 25, the opening / closing member 26, and the spring 27 and the set ring 28 is also provided on the outer wall surface of the shutter base plate 2. The operating pin of the opening / closing member is the same as the operating pin 7a in the first embodiment, and the slot 18 of the link member 18
a.

Next, the operation of this embodiment will be described. FIG.
Does not show the set state as described above.
In the set state, the set ring 28 is rotating more clockwise than the state of FIG. 6, the cam surface 28a pushes the operating pin 26b, and the iron piece 26a is moved to the iron core member 25a against the force of the spring 27. In contact with it. The same applies to the drive system and the set ring of the closing blade group. When the shutter button is pressed in such a set state, the power switch is first closed, and power is supplied to the photoreflector (not shown) in the same manner as in the first embodiment. Coil 25
b, so that the iron piece 26a is attracted to the iron core member 25a. Then, the setting member 28 is rotated counterclockwise, the cam surface 28a is separated from the operating pin 26b, and the opening / closing member 26 is rotatable, as shown in FIG. This is the same for the drive system and the set ring of the closing blade group.

Thereafter, in the state shown in FIG.
When the power is cut off, the opening / closing member 26 is rapidly rotated counterclockwise by the force of the spring 27,
The link member 10 is operated upward. Thereafter, in the same manner as in the first embodiment, the link member 10 opens and the shutter blades 11, 12, and 13 of the blade group rotate counterclockwise to open the opening 1b. And the opening 1b
Is fully opened, the operation pin 26b comes into contact with the upper end surface of the hole 1c, and the operation is stopped. Thereafter, or immediately before the stop of the shutter blades 11, 12, and 13, the energization of the coil of the other electromagnet is cut off, and the link member 18 is similarly operated upward, and the shutter blades 19 and 2 of the closing blade group are closed.
Rotate 0, 21 counterclockwise to close the opening,
The exposure operation ends.

When the exposure operation is completed, the set ring 28 is first rotated clockwise in association with the winding of the film. Therefore, the operating pin 26b is pushed by the cam surface 28a, and the opening / closing member 26 rotates clockwise against the force of the spring 27. With this rotation, the link member 10 operates downward, and rotates the shutter blades 11, 12, and 13 clockwise to cover the opening 1b. Then, when the shutter blades 11, 12, and 13 completely cover the opening 1b and the iron piece 26a of the opening / closing member 26 comes into contact with the iron core member 25a, the rotation of the set ring 28 stops. afterwards,
The other set ring starts rotating, and operates the link member 18 downward in the same manner as described above, and the shutter blade 1
9, 9, 21 are set to the state shown in FIG. 3 in the same manner as in the first embodiment, and the setting operation is completed.

In the above description of the setting operation, it has been described that the rotation of the set ring 28 is stopped when the iron piece 26a comes into contact with the iron core member 25a. It is. Therefore, the iron piece 26
a immediately before contact with the iron core member 25a.
The rotation of 8 may be stopped. in short,
When the coil 25b of the electromagnet 25 is energized, the iron core member 25a only needs to be able to reliably attract the iron piece 26a.

Next, a third embodiment of the present invention shown in FIG. 7 will be described. In contrast to the above-described second embodiment in which the opening / closing member 26 and the link member 10 are pin-slot-coupled,
This embodiment is similar to the first embodiment in that the operating pins 26
b is engaged with the concave portion 10a of the link member 10. Therefore, in this embodiment, the spring 17 is provided as in the first embodiment.
The connection relationship between the other opening / closing member and the link member 18 may be the same, or may be a pin / slot connection. Since other configurations are completely the same as those of the second embodiment, the same members and the same parts as those shown in the first and second embodiments are denoted by the same reference numerals. Further, the operation of the present embodiment can be understood very clearly from the description of the operations of the first and second embodiments, and thus the description thereof will be omitted.

[0041]

As described above, according to the present invention, an annular or arc-shaped link member disposed so as to surround a circular exposure opening is reciprocated in a direction crossing the optical axis. A shutter configured to reciprocate three or more shutter blades pivotally mounted at predetermined intervals around the opening, wherein the two blade groups are operated by separate driving means, so that exposure is performed. The time can be shortened, and when a moving magnet type motor is used as the driving means, the opening operation of the shutter blades can be stabilized by applying a spring force to the link member. Therefore, the camera shutter of the present invention can be used for a camera having a relatively large lens aperture, and is most suitable for a camera requiring high performance.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view necessary for understanding a skeleton of a configuration of a first embodiment.

FIG. 2 is a plan view showing a setting state of a group of opening blades in the first embodiment.

FIG. 3 is a plan view showing a set state of a closing blade group in the first embodiment.

FIG. 4 is a plan view showing a fully opened state of an opening blade group in the first embodiment.

FIG. 5 is a plan view showing a state immediately after the exposure operation of the closing blade group is completed in the first embodiment.

FIG. 6 is a plan view of a main part of the second embodiment, showing a state immediately before an exposure operation is started.

FIG. 7 is a plan view of a main part of the third embodiment, showing a state immediately before an exposure operation is started.

[Explanation of symbols]

1, 2 Shutter base plate 1a, 2a Base 1b, 2b, 3a Opening 1c, 1m, 2c, 10f, 10g, 10h, 18b,
18c, 18d Holes 1d, 1e, 1f, 2d, 2e, 2f Receiving portions 1g, 1h, 1i, 1j, 1n, 2g, 2h, 2i Shaft 1k Spring hook 3 Partition plate 4, 5 Moving magnet type motor 4a, 5a Rotation Child 4b, 5b Upper frame 4c, 5c Lower frame 4d, 5d, 25b Coil 4e, 5e Yoke 6, 7, 26 Opening / closing member 6a, 7a, 26b Operating pin 8, 9 Screw 10, 18 Link member 10a Recess 10b Contact portion 10c, 10d, 10e, 18e, 18f, 18g Overhanging portion 10i, 18a Slot 11, 12, 13, 19, 20, 21 Shutter blade 13a, 21a Projection 14, 15, 16, 22, 23, 24 Connecting shaft 17 , 27 spring 25 electromagnet 25a iron core member 26a iron piece 28 set ring 28a cam surface

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[Procedure amendment]

[Submission date] June 4, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

In particular, when a moving magnet type motor is used as a driving source, such a problem becomes more remarkable. As described above, moving-magnet motor can not be said to be very driving force is large, also Suteppi
A difficulty in starting performance as compared to the ring motor. for that reason,
It takes a long time from the start of energization until a predetermined driving force is obtained , and the driving force is easily affected by a slight variation in load or a change in supply voltage, as in the shutter described in the above publication. In the case of a shutter that operates three or more shutter blades, the load becomes large as compared with a shutter having a two-blade configuration, and it is extremely difficult to stably obtain a high speed.

Claims (8)

[Claims] 1. Two shutter base plates each having a circular opening centered on an optical axis, a partition plate partitioning between the two shutter base plates and forming a first blade chamber and a second blade chamber. , Each of which is composed of three or more blades, is separately disposed in the first blade chamber and the second blade chamber, and each blade has a fulcrum portion and a moving point portion, and the opening is provided at the fulcrum portion. A first shutter blade group and a second shutter blade group configured to be able to reciprocate between an opening position and a closing position so that one of the openings is opened and the other is closed during an exposure operation; And are arranged so as to surround the openings in the first blade chamber and the second blade chamber, respectively, and are rotatably connected to the moving point portions of the respective blades so as to cross the optical axis. Each blade is reciprocated in the direction A first link member and a second link member for reciprocating rotation at each fulcrum, and a first link member and a second link member provided outside the blade chamber and capable of reciprocating each other and interlocking with the reciprocating operation. A camera shutter, comprising: a first drive unit and a second drive unit that enable reciprocal operation of a two-link member. 2. The first driving means and the second driving means,
Each of the motors comprises a reciprocally rotatable motor and an opening / closing member reciprocally operated by the motor. During the exposure operation, the first shutter blade group performs an opening operation, and the second shutter blade group closes. The first link member is operated by a spring.
2. The camera shutter according to claim 1, wherein the shutter blade group is urged in a direction to open the shutter blade group and engages with one of the opening and closing members. 3. A motor constituting the first driving means,
A moving magnet type motor, wherein in a set state, the magnetic force of the permanent magnet rotor overcomes the urging force of the spring to hold the first link member at the set position. The camera shutter according to claim 2. 4. The first driving means and the second driving means,
Each is constituted by a reciprocally rotatable motor and an opening / closing member reciprocally operated by the motor, and these opening / closing members are pin-slot-coupled to the first link member and the second link member. Claim 1
2. The camera shutter according to 1. 5. The motor according to claim 1, wherein each of the motors is operated only when the exposure operation is performed, and the first shutter blade group and the second shutter blade group perform an opening operation and a closing operation during the exposure operation. The camera shutter according to claim 4, wherein the shutter operation is performed alternately. 6. At the time of an exposure operation, the first shutter blade group performs an opening operation, the second shutter blade group performs a closing operation, and at least the first link member of the motor is connected. The camera according to claim 4, wherein the motor to be operated is a moving magnet type motor, and the first link member is biased by a spring in a direction to open the first shutter blade group. Shutter. 7. An exposure operation, wherein the first shutter blade group performs an opening operation and the second shutter blade group performs a closing operation, and the first driving means and the second driving means perform a closing operation. At least one of them is an opening / closing member that is connected to the link member by a pin / slot connection and is given a rotation behavior in one direction by a spring, and the opening / closing member is released by an electromagnet during an exposure operation, 2. The camera shutter according to claim 1, wherein the shutter is rotated by the spring, and is rotated to a contact position with the electromagnet against the spring by a setting member at the time of setting. 8. The connecting relationship between the opening / closing member and the link member is such that the link member is urged by another spring to engage with the opening / closing member, and the opening / closing member is released by the electromagnet. The camera shutter according to claim 7, wherein the camera shutter is configured to operate following the rotation.