JP2518341Y2 - Focal plane shutter - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a focal plane shutter, and more particularly to a focal plane shutter provided with a cushioning mechanism capable of effectively absorbing a shock at the advanced end of each blade group forming the focal plane shutter with a simple structure.

[Prior art]

In recent years, focal plane shutters for single-lens reflex cameras are attempting to increase the curtain speed in order to stabilize the high-speed exposure seconds and increase the flash synchronization speed. While it was common for the vehicle to travel 24 mm in about 7 ms, in recent years it has come to travel in about 3 ms. On the other hand, it is well known that an increase in the curtain speed leads to an increase in operating noise and vibration at the advanced end, and further deterioration in durability. In the case of a focal plane shutter with a high curtain speed, effective cushioning is effective. A mechanism is needed. As a conventional cushioning mechanism, a brake lever, which is pressed against a friction plate and a leaf spring, is arranged on the passage path of the blade drive member, and the brake lever is rotated by the rear impact of the blade drive member to rotate the blade drive member and the shutter blade. It is generally known that the kinetic energy of the above is converted into heat energy due to the friction between the friction plate and the brake lever to absorb the impact.

[Problems to be solved by the device]

However, the shock absorbing mechanism of this type has a problem that the friction coefficient between the members is affected by temperature changes and aging changes, and thus the shock absorbing performance is also easily changed.
In addition to the shutter drive mechanism, a space for arranging a shock absorbing brake lever and a friction mechanism is required.
In addition to the shutter drive mechanism, the impact absorption mechanism must be charged during the charging operation, which also increases the amount of charging power.

[Means for solving problems]

The present invention has been made in view of these problems, and has stable buffering performance, a small installation space, and
It is an object of the present invention to provide a focal plane shutter having a shock absorbing mechanism that does not require an increase in charging power. In summary, the focal plane shutter of the present invention is: pivotally mounted on the shutter base plate and connected to a blade group composed of a plurality of divided blades, and the blade group is placed between the expanded state and the superposed state. A drive lever that is driven by a vehicle; and a swing lever that is swingably attached to a shaft provided on a position different from the turning shaft of the drive lever itself on the drive lever,
A reversing lever whose rotation range is restricted relative to the drive lever; a fixed end is provided outside the drive lever,
Urging means having an operating end engaged with the free end of the reversing lever and urging the reversing lever toward the forward limit of the drive lever; and a swing shaft of the reversing lever and the urging shaft on the reversing lever. A rotating cam rotatably attached to an intermediate portion of an engaging point of the urging means; operating along a traveling motion line of the rotating cam,
The drive lever is moved toward the initial position while engaging the rotary cam at the time of reverse running, and a set cam capable of retreating from the traveling operation line of the rotary cam is provided; the drive lever reaches the forward limit. A cam edge that suppresses a pivoting motion of the rotary cam about the swing axis of the drive lever is fixedly formed with respect to the shutter base plate at a position before the rotation. More preferably, the focal plane shutter of the present invention is based on the above, wherein the cam edge is formed on a cam plate fixed to the shutter base plate, and the mounting position of the cam plate with respect to the shutter base plate is adjustable. It was done. More preferably, on the premise of the above, the focal plane shutter of the present invention has a tangent line of the running trajectory immediately before the rotary cam contacts the cam edge and a tangent line of the cam edge immediately after the rotary cam contacts the cam edge. The feature is that they cross at an obtuse angle.

[Action]

That is, according to the focal plane shutter of the present invention, the reversing lever is urged toward the forward limit of the drive lever, and the relative turning limit with respect to the drive lever toward the forward limit of the drive lever is set. Since it is regulated, the urging force applied to the reversing lever causes the reversing lever to travel with the drive lever toward the forward limit of the drive lever.
In this traveling process, the rotary cam pivotally attached to the reversing lever reaches the cam edge before the drive lever reaches the forward limit, and the turning motion of the rotary cam is suppressed by this cam edge, and the reversing lever acts as the drive lever. The axle bearing part of the car runs first. Since this rotary cam is provided at the intermediate portion of the engaging point between the shaft attachment portion of the reversing lever and the drive lever and the biasing means,
After the rotary cam comes into contact with the cam edge, the biasing force of the biasing means is reversed around the location of the rotary cam as a fulcrum and transmitted to the drive lever, so that a braking force is applied to the drive lever.
Shock and vibration at the forward limit are alleviated. Further, when the set cam is retracted from the traveling motion line of the rotating cam, the drive lever is returned toward the initial position while engaging the rotating cam when the traveling direction of the rotating cam is reversed. Serves as both the roller for the initial setting of the blade and the cushioning member. Further, when the mounting position of the cam plate with respect to the shutter base plate is adjustable, the timing of applying the braking to the drive lever can be finely adjusted by adjusting the mounting position. Furthermore, when the tangent line of the running trajectory of the rotary cam just before the contact with the cam edge intersects the cam edge at an obtuse angle, the incident angle of the rotary cam with respect to the cam edge becomes an obtuse angle. There is less impact and vibration when the butt contacts the cam edge.

【Example】

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a front view of a front plane 1 and a rear plane 2 of a focal plane shutter according to an embodiment of the present invention. FIG. 7 is a plan view showing an initial state of the connecting levers 5 and 6 for exposure, and an exposing aperture 7a formed in a central portion of the main plate 7 is shielded by the front blade 1 in an initial state. First, the connecting lever 3 is swingably supported by the shaft 8 and the connecting lever 4 is swingably supported by the main plate 7 by the shaft 9. The blades 1a, 1b, 1c, 1d that make up the leading blade 1 are each a screw.
The connecting lever 3 is rotationally swaged by the screws 3a, 3b, 3c, and 3d, and the connecting lever 3 is rotationally swaged by the screws 4a, 4b, 4c, and 4d. In addition, the bent portion that penetrates the slot 7b formed in the main plate 7
10 is engaged with the connecting lever 3, and when the bent portion 10 is lowered along the slot 7b, the connecting lever 3 rotates right about the shaft 8, and in conjunction with this, the connecting lever 4 also moves around the shaft 9. The blades 1a ・ 1b ・ 1c ・
1d travels downward to open aperture 7a. Similarly, the connecting lever 5 is connected to the connecting lever 6 by the shaft 11.
The shafts 12 are swingably supported by the ground plate 7, respectively. Each of the blades 2a, 2b, 2c, 2d that form the rear blade 2 is a screw.
The connecting lever 5 is rotationally swaged by the connecting levers 5a, 5b, 5c, and 5d, and the connecting lever 6 is rotationally swaged by the screws 6a, 6b, 6c, and 6d. Also, the bent portion that penetrates the slot 7c formed in the base plate 7
30 is engaged with the connecting lever 5, and when the bent portion 30 is moved down along the slot 7c, the connecting lever 5 rotates right about the shaft 11, and in conjunction with this, the connecting lever 6 also moves around the shaft 12. The blades 2a ・ 2b ・ 2c ・
2d runs downward and shields the aperture 7a. In the focal plane shutter shown in FIG. 1, the time difference from the start of the leading blade 1 to the start of the trailing blade 2 corresponds to the exposure time, but it stabilizes the high-speed exposure time. In order to increase the flash synchronization speed, it is necessary to increase the curtain speed of the leading blade 1 and the trailing blade 2. However, when the curtain speed is increased, a large shock or vibration is generated at the end of the operation of each blade, and the focal plane shutter of the present invention has a new shock absorbing mechanism to absorb the shock at the end of the shutter operation. To have. The specific structure is shown in FIGS. 2 to 9. In these drawings, FIG. 2 shows the state immediately after the shutter charge is finished, FIG. 3 shows the state immediately before the start of the leading blade, and FIG. 4 shows the leading blade and the trailing blade in the forward limit. FIG. 5 shows a state in which the leading blades are disengaged in the forward limit, and FIG. 6 shows a state in which the trailing blades are disengaged in the forward limit. Further, FIG. 7 is an enlarged view showing a drive mechanism portion of the leading blade 1, FIG. 8 is an enlarged view showing a drive mechanism portion of the trailing blade 2, and FIG. 9 is a cam plate for the trailing blade. It is sectional drawing of the attachment part of. Further, among the mechanical elements shown in FIGS. 2 to 8, many elements are urged by springs,
In order to avoid complicating the drawing, only the biasing direction is indicated by the arrow except for the spring which is important for the present invention.
Further, in order to avoid complication of the drawings, in FIGS. 3 to 6, reference numerals are attached only to the elements referred to in the main text of the specification when explaining each operation state. First, the drive mechanism of the leading blade will be described. A front blade drive lever 15 having a bent portion 10 formed on the back surface is swingably supported on a shaft 14 on the main plate 7, and the front blade 1 runs on a shaft 15a on the back surface of the front blade drive lever 15. A reversing lever 16 that transmits a driving force to the leading blade 1 in the first half region of the operation and transmits a braking force to the leading blade 1 in the second half region of the traveling operation of the leading blade 1 swings freely. It is worn. The bent portion 16a formed at the tip of the reversing lever 16 penetrates the hole 15b formed in the leading blade drive lever 15,
A free end 17a of a torsion spring 17 for driving is engaged with the bent portion 16a, and a fixed end of the torsion spring 17 is engaged with a pin 18 fixed to a camera body (not shown). Therefore, the force exerted by the torsion spring 17 on the reversing lever 16 can be transmitted to the leading blade actuating lever 15 as a right-handed force about the shaft 14 via the bending portion 16a and the edge 15c of the hole 15b. Has been done. On the back surface of the reversing lever 16, a rotary cam 19 which also serves as a set roller is rotatably mounted at an intermediate portion between the shaft 15a and the bent portion 16a, and the main plate 7 has a cam plate for controlling the traveling locus of the rotary cam 19. A shaft 20 is fixed to the shaft 14 by a shaft 42 described later. Although the operation of the cam plate 20 will become clearer in the description of the operation to be described later, the cam plate 20 is formed with a cam edge 20a for restricting the right rotation of the rotary cam 19 accompanying the right rotation of the leading blade drive lever 15. . The cam edge 20a is formed at a position where the rotary cam 19 abuts before the leading blade drive lever 15 reaches the forward limit, and the rotary cam 19 travels immediately before the rotary cam 19 contacts the cam edge 20a. The shape of the cam edge 20a is set so that the tangent line of the locus and the cam edge 20a intersect at an obtuse angle. Next, the drive mechanism of the rear blade will be described. In the present embodiment, the drive mechanism of the trailing blade is essentially the same as the drive mechanism of the leading blade, so the elements in the driving mechanism of the trailing blade are attached to the same types of elements in the leading blade driving mechanism. The explanation is simplified by giving a reference numeral obtained by arithmetically adding 20 to the reference numeral. In the drive mechanism on the trailing blade side, the mounting structure of the cam plate is different from that on the leading blade side, but this shows a modification of the embodiment, and the leading blade side will be described in detail below. It is needless to say that the rear blade side, which will be described in detail below, can be configured in the same manner as the front blade side described above. A rear blade drive lever 35 having a bent portion 30 formed on the rear surface thereof is swingably supported on a shaft 34 on the main plate 7, and a reversing lever 36 is mounted on a shaft 35a on the rear surface of the rear blade drive lever 35. It is pivotally mounted. The bent portion 36a formed at the tip of the reversing lever 36 has a hole 3
The free end 37a of the torsion spring 37 is engaged through the 5b, and the fixed end of the torsion spring 37 is engaged with the pin 38. Therefore, the force exerted by the torsion spring 37 on the reversing lever 36 may be transmitted to the rear blade actuating lever 35 as a right-handed force about the shaft 34 via the bending portion 36a and the edge 35c of the hole 35b. Has been done. A rotating cam 39 is attached to the back surface of the reversing lever 36, and a cam plate for controlling the traveling locus of the rotating cam 39 is attached to the main plate 7.
40 is fixed by the shaft 34 and the shaft 62. The cam plate 40 is formed with a cam edge 40a for restricting right rotation of the rotary cam 39 associated with right rotation of the trailing blade drive lever 35. The cam edge 40a is formed at a position where the rotary cam 39 contacts before the trailing blade drive lever 35 reaches the forward limit.
Moreover, the point where the shape of the cam edge 40a is formed so that the tangent line of the running trajectory of the rotary cam 39 immediately before the contact of the rotary cam 39 with the cam edge 40a and the cam edge 40a intersect at an obtuse angle is on the leading blade side. Although the same, the attachment structure of the cam plate 40 to the base plate 7 is different from the cam plate 20 on the leading blade side. Specifically, the cam plate 20 on the leading blade side is fixed to the base plate 7 by the shaft 14 and the shaft 42, while the cam plate 40 on the trailing blade side is mounted on the shaft 34.
And a shaft 62 for fixing the position. FIG. 9 is a cross-sectional view showing a portion of the shaft 62, in which a adjusting sledge 62a is formed on the head flange of the shaft 62.
Is penetrated through the adjusting groove 40b formed in the cam plate 40 and screwed with the base plate 7. Since the eccentric shaft 62b is formed on the shaft 62 so that the inner width of the adjusting groove 40b is equal to the diameter of the adjusting groove 40b, the cam plate 40 is turned around the shaft 34 by rotating the shaft 62 by the sliwer 62a. Therefore, the angle of the cam edge can be finely adjusted. Next, 41 is a set lever for initially setting the shutter mechanism. The set lever 41 is swingably supported by the shaft 42 described above,
It is connected to the set cam 44 via the set link 43, and the set lever 41 is connected to the shaft 42 against the biasing force of the spring.
When rotated right about, the set cam 44 rotates right about the shaft 45. The cam surface 44a formed on the set cam 44 contacts the rotating cam 19 described above, and when the set cam 44 is rotated clockwise, the leading blade drive lever 15 is rotated counterclockwise. Further, the cam surface 44b formed on the set cam 44 contacts the rotating cam 39 described above, and when the set cam 44 is rotated right, the rear blade drive lever 35 is rotated counterclockwise. Next, 46 is a leading blade bound stopper that engages the leading blade drive lever 15 when the leading blade finishes traveling,
Reference numeral 47 is a trailing blade bound stopper that engages the trailing blade drive lever 35 when the trailing blade finishes traveling. The leading blade bound stopper 46 is attached to the shaft 48 and the trailing blade bound stopper 46.
Each of the shafts 47 is attached to a shaft 49. Incidentally, more detailed structures of the leading blade bound stopper 46 and the trailing blade bound stopper 47 will be made clear in the following operation description. Furthermore, 50.5
1 indicates a magnet for electromagnetic release. Next, the operation of this embodiment will be described with reference to the above items. First, in the initial state, the peripheral mechanism of the shutter blade is in the state shown in FIG. 1, and the drive mechanism thereof is in the state shown in FIG. In this initial state, the urging force in the left-handed direction given to the set lever 41 from the spring is transmitted as the left-handed force to the set cam 44 via the set link 43, but the set cam 44 is not shown in the figure. The counterclockwise rotation of the set cam 44, which is engaged with the release lever, is restricted in the state shown in FIG. Now, when the set cam 44 is released from the release lever (not shown) from the state shown in FIG. 2, the left turning force given from the spring to the set lever 41 is transmitted to the set cam 44 via the set link 43, and the set cam 44 is set. The cam 44 turns counterclockwise. By the left rotation of the set cam 44, the cam surface 44a of the set cam 44 and the rotary cam 19 on the leading blade side are separated from each other, and similarly, the cam surface 44b of the set cam 44 and the rotary cam 39 on the trailing blade side are separated from each other. Therefore, the reversing lever 16 is rotated counterclockwise about the shaft 15a by the urging force of the torsion spring 17 so that the bent portion 16a has the leading blade drive lever.
It contacts the edge 15c of the hole 15b formed in 15 and exerts a right turning force on the leading blade drive lever 15. Similarly, the reversing lever 36 is rotated counterclockwise about the shaft 35a by the urging force of the torsion spring 37, and the bent portion 36a abuts the edge 35c of the hole 35b formed in the trailing blade driving lever 35 to drive the trailing blade. A right turning force is exerted on the lever 35. The state at this time is as shown in FIG. 3. In the state of FIG. 3, the iron piece 15d provided on the leading blade drive lever 15 is attached to the magnet 50 and the iron piece 15d provided on the trailing blade drive lever 35. Since 35d is attracted to the magnet 51, the leading blade 1 and the trailing blade 2 maintain the initial state. Now, after the set cam 44 is released, the magnets 50 and 51 are sequentially demagnetized with a time difference corresponding to the exposure time. Describing mainly on the leading blade side, the biasing force of the spring 17 is transmitted to the leading blade driving lever 15 through the bent portion 16a of the reversing lever 16 and the edge 15c of the hole, and the leading blade driving lever 15
Turns right about axis 14. Therefore, since the bent portion 10 formed on the back surface of the leading blade drive lever 15 descends along the slot 7b, the connecting lever 3
Rotates right about the shaft 8, and in conjunction with this, the connecting lever 4 also rotates right around the shaft 9, so that the blades 1a, 1b, 1c, 1d forming the leading blade 1 run downward. Open the aperture 7a. Now, in the process in which the reversing lever 16 and the leading blade driving lever 15 integrally rotate, the rotating cam 19 contacts the cam edge 20a formed on the cam plate 20 before the leading blade driving lever 15 reaches the forward limit. To do. Even after the rotary cam 19 contacts the cam edge 20a, the leading blade drive lever 15 continues to turn to the forward limit due to its own inertial force and the inertial force of the related mechanism of the leading blade 1.
Therefore, the shaft 15a of the reversing lever 16 continues to turn integrally with the leading blade drive lever 15. On the other hand, since the turning motion of the rotating cam 19 is restricted by the cam edge 20a, the reversing lever 16 rotates right about the shaft 15a relative to the leading blade driving lever 15, and the reversing lever 16 rotates. Since the bent portion 16a formed in 16 is separated from the edge 15c of the hole of the leading blade driving lever 15, the right turning force from the torsion spring 17 is not transmitted to the leading blade driving lever 15. Moreover, since the free end of the torsion spring 17 is still engaged with the bending portion 16a of the reversing lever 16 even at this time, the force exerted by the torsion spring 17 on the bending portion 16a of the reversing lever 16 rotates. It is transmitted to the shaft 15a of the reversing lever 16 with the cam 19 as a fulcrum. Then, this force acts on the leading blade drive lever 15 as a left-handed turning force about the shaft 14. As described above, in the present embodiment, even after the rotary cam 19 contacts the cam edge 20a of the cam plate 20, the leading blade drive lever 15 travels to the forward limit due to the inertial force of itself and the leading blade-related mechanism, After the cam 19 comes into contact with the cam edge 20a of the cam plate 20, not only does it not receive the right-handed force from the torsion spring 17, but the force of the torsion spring 17 is reversed by the reversing lever 16 and becomes a braking force. Since it is transmitted, shocks and vibrations at the end of running are greatly reduced. Then, the engaging protrusion 15 formed on the leading blade driving lever 15
e is engaged with the leading blade bound stopper 46, and the leading blade drive lever 15 stops. Also, the operation of the drive mechanism on the trailing blade side is exactly the same as that on the leading blade side, and the engaging projection 35e formed on the trailing blade driving lever 35
Is engaged with the trailing blade bound stopper 47, and the trailing blade drive lever 35 also stops. The state at this time is the state shown in FIG. Now, after one exposure operation is completed as described above, when the set lever 41 is rotated clockwise about the shaft 42 against the biasing force of the spring in conjunction with the film winding operation by the motor or manually. , The set cam 44 rotates right through the set link 43. As the set cam 44 rotates to the right, the cam surface 44c formed on the set cam 44 causes the leading blade bound stopper 46 to rotate counterclockwise about the shaft 48, so that the leading blade bound stopper 46 and the leading blade drive lever 15 are engaged. The engagement with the protruding piece 15e is released. At this point, the leading blade drive lever 15 has a torsion spring.
Since the force of 17 is inverted and transmitted by the reversing lever 16 with the rotating cam 19 as a fulcrum, when the engagement by the leading blade bounding stopper 46 is released as described above, the leading blade drive lever 15 has a hole portion. The edge 15c is turned counterclockwise until it contacts the bent portion 16a of the reversing lever 16. The state at this time is the state shown in FIG. Then, when the set cam 44 is further turned to the right, the set cam is rotated.
The cam surface 44d formed on 44 is the rear blade bound stopper 47.
Is rotated left about the shaft 49, the engagement between the trailing blade bounding stopper 47 and the engaging projection 35e of the trailing blade drive lever 35 is released. Therefore, the trailing blade drive lever 35 is also a torsion spring.
The urging force of 37 causes the edge 35c of the hole to rotate counterclockwise until it contacts the bent portion 36a of the reversing lever 36. The state at this time is the state shown in FIG. In this embodiment, since there is a slight time difference between the disengagement on the leading blade side and the disengagement on the trailing blade side, there is no risk of exposing the exposing aperture when the blade is returned. After that, when the set cam 44 is further turned to the right, the set cam is rotated.
The cam surface 44a formed on the front blade 44 comes into contact with the rotary cam 19 on the leading blade side, and the cam surface 44b formed on the set cam 44 comes into contact with the rotary cam 39 on the rear blade side. Then, the rear blade drive lever 35 is rotated counterclockwise to reach the initial position shown in FIG. In the above description, the cam plate 20 (40) on which the cam edge 20a (40a) is formed is fixed to the base plate 7, but the cam edge 20a (40a) is directly formed on the base plate 7. Is also good.

【effect】

As described above, according to the present invention, a single spring is
The shutter blade is used as a driving force source for traveling until the middle of the traveling movement of the shutter blade, and is used as a force source for braking of the shutter blade during the traveling movement of the shutter blade. There is no need to provide a spring separately, and the installation space for the braking mechanism is saved. Further, according to the present invention, since there is no member that causes friction due to the braking of the shutter blade, it is not affected by the fluctuation of the friction coefficient due to the temperature change, and the stable shutter opening is achieved regardless of the use environment of the camera. The characteristics can be obtained, and there is no deterioration in shock absorption capacity due to abrasion. Further, as described above, in the present invention, since the shutter driving spring also serves as the shutter braking force source, it is not necessary to charge the braking mechanism separately from the shutter driving mechanism, and an increase in charging force can be prevented. . Further, in the case of the present invention, since the incident angle of the rotary cam with respect to the cam edge is an obtuse angle, there is substantially no member that causes a rear-end collision, and wear due to a rear-end collision is extremely small. Further, in the case of the present invention, the only member mechanically added is the reversing lever, and the rotating cam pivotally mounted on the reversing lever also serves as the set roller normally provided in the shutter mechanism of this type. Therefore, the structure is extremely simple. Furthermore, if the mounting position of the cam plate is adjustable,
It is possible to easily make adjustments so as to obtain ideal cushioning performance within a range in which the blade group can reliably travel to the forward limit, and it is also possible to easily make adjustments in cushioning performance during repairs and the like.

[Brief description of drawings]

1 is a plan view of a blade peripheral mechanism of a focal plane shutter according to one embodiment of the present invention, FIG. 2 is a plan view showing a shutter charge state of a shutter driving mechanism according to one embodiment of the present invention, and FIG. 2 is a plan view showing a state immediately before the leading blade of the mechanism shown in FIG. 2 is started to travel, and FIG.
FIG. 5 is a plan view showing a state in which the leading blade and the trailing blade of the mechanism shown in the figure are engaged at the forward limit, and FIG. 5 shows the engagement of the leading blade of the mechanism shown in FIGS. 2 to 4 at the forward limit. FIG. 6 is a plan view showing a state in which the rear blades of the mechanism shown in FIGS. 2 to 5 are disengaged at the forward limit, and FIG. 8 is an enlarged view of the drive mechanism, FIG. 8 is an enlarged view of the drive mechanism on the trailing blade side, and FIG. 9 is a sectional view showing the mounting structure of the cam plate on the trailing blade side. 1 …… Leading blade 1a ・ 1b ・ 1c ・ 1d …… Blade 2 …… Rear blade 2a ・ 2b ・ 2c ・ 2d …… Blade 3/4/5/6 …… Connecting lever 7 …… Main plate, 7a …… Aperture 7b ・ 7c …… Slot, 10 …… Bending portion 15 …… Leading blade drive lever, 15b …… Hole portion 15c …… Edge, 16 …… Reversing lever 16a …… Bending portion, 17 …… Torsion spring 19… … Rotating cam, 20 …… Cam plate 20a …… Cam edge, 30 …… Bending section 35 …… Leading blade drive lever, 35b …… Hole section 35c …… Edge, 36 …… Reversing lever 36a …… Bending section, 37 ...... Torsion spring 39 …… Rotating cam, 40 …… Cam plate 40a …… Cam edge, 40b …… Adjustment groove 44 …… Set cam, 44a …… Cam surface 44b …… Cam surface, 62 …… Axis

Claims (3)

(57) [Scope of utility model registration request] 1. A drive lever which is pivotally mounted on a shutter base plate and is connected to a blade group composed of a plurality of divided blades, and which drives the blade group between a developed state and a superposed state. A reversing lever, which is swingably attached to a shaft provided at a position different from the turning shaft of the driving lever itself on the driving lever and whose turning range is restricted with respect to the driving lever, and a fixed end. Urging means provided outside the drive lever, having an operating end engaged with a free end of the reversing lever, for urging the reversing lever toward the forward limit of the drive lever, and on the reversing lever, A rotating cam rotatably attached to an intermediate portion between the swing shaft of the reversing lever and the engaging point of the biasing means, and a rotating cam that operates along the traveling motion line of the rotating cam and moves in the reverse direction. The drive lever to the initial position while engaging And a set cam capable of retreating from the traveling motion line of the rotary cam and centering the swing shaft of the drive lever of the rotary cam at a position before the drive lever reaches the forward limit. The focal plane shutter is characterized in that a cam edge for suppressing the turning motion is fixedly formed with respect to the shutter base plate. 2. The focal plane shutter according to claim 1, wherein the cam edge is formed on a cam plate fixed to the shutter base plate, and the cam plate is attached to the shutter base plate. A focal plane shutter whose position can be adjusted. 3. The focal plane shutter according to claim 1 or 2, wherein the rotary cam has a tangent to a running trajectory immediately before the rotary cam contacts the cam edge, and the rotary cam is aligned with the cam edge. A focal plane shutter characterized in that the tangent line of the cam edge immediately after contact intersects at an obtuse angle.