JPS623789Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a two-ring type lens shutter, and more particularly to a two-ring type lens shutter that uses a shutter opening ring and a shutter closing ring to open and close a shutter blade.

As is well known, a two-ring lens shutter has a shutter opening ring that controls the opening operation of the shutter blade and a shutter closing ring that controls the closing operation of the shutter blade. It is designed to open and close depending on the movement.

By the way, in order to obtain a high-speed exposure time using this two-ring shutter, the opening ring first rotates to open the shutter blades, and then when the exposure time has elapsed, Rotation of the closing ring must cause the shutter blades to close immediately. However, when the closing ring rotates to close the shutter blades, the opening ring is still rotating.
The shutter blade must be closed by making the rotational movement of the closing ring faster than the rotational movement of the closing ring. Furthermore, in this type of shutter, the shutter opening ring is provided with a speed regulating mechanism in order to keep the opening speed of the shutter blades constant.

Figure 1 shows the relationship between the shutter opening degree l and time t in this type of shutter.The shutter opening degree l increases linearly in proportion to time t, and when the shutter is fully opened, The time opening degree l reaches ₀ . In this shutter, this time
At t ₁ , the proper exposure time is reached, the closing ring begins to rotate, and even if you try to close the shutter blades, the opening ring is still rotating, so the shutter blades do not close immediately, and the rotation of the closing ring stops the opening ring. At time t ₃ when it catches up with the rotation of , the shutter blade closes completely and its opening becomes zero. Therefore, compared to time _t1 , the shutter is opened an extra time _t3 - _t1 , resulting in overexposure.

The purpose of this invention is that even if the closing ring begins to rotate,
In order to eliminate the conventional drawback that the shutter closing time is delayed due to the opening ring still rotating, the shutter closing time is delayed at the same time as the closing ring starts rotating.
To provide a two-ring type lens shutter which applies a brake to the opening ring and immediately stops the operation of the opening ring.

According to the present invention, the brake is applied to the open ring at the same time as the closing ring starts to rotate.
The ring stops and the shutter blade closes immediately, reducing overexposure. That is, as shown in Fig. 1, the time for the shutter to completely close can be reduced from the conventional time t ₃ to time t ₂ , which reduces overexposure and allows accurate high-speed exposure time to be obtained. can.

In addition, the two-ring lens shutter of the present invention skillfully utilizes the speed regulating mechanism provided in a normal two-ring lens shutter as a braking means for applying a brake to the shutter opening ring. Therefore, the brake device can be constructed easily and economically.

Hereinafter, the present invention will be explained with reference to an illustrated embodiment.

In FIG. 2, a shutter housing housing 46 for storing a shutter mechanism is formed by overlapping two cover plates 1 and 2 with their opening surfaces facing each other. In addition, the above-mentioned both lid plates 1 and 2
When separated, the interior of each cover plate body 1, 2 is exposed. As shown in FIG. 3, inside the upper cover plate 1, there are a shutter closing ring 3, a shutter opening ring 4, a shutter blade 5, and a shutter opening ring locking member which is housed in the housing 46. Stop lever 6, magnet Mg ₁ for shutter opening control, shutter closing ring starting lever 8 of the locking member, magnet Mg ₂ for shutter closing control, gears 10, 30, pinion 29, escape wheel 11, pallet wheel 12, charge The shutter mechanism including the member 18, drive springs 13, 14, 15, etc. is mainly housed, and the lower cover plate body 2
serves to cover the upper cover plate body 1. Furthermore, as shown in FIG. 2, circular openings 47 and 57 are provided at the center of the lid plates 1 and 2, respectively, to form optical paths for photographing. A stepped portion 5 for attaching photographing lenses 19 and 20 is provided on the outer periphery.
8,59 are provided. And this stepped part 5
Photographing lenses 19 and 20 are fixed to lenses 8 and 59 by fixing rings 60 and 61, respectively.

Now, as shown in FIG.
A shutter opening ring 4 is arranged around the opening 47 to control the opening of the shutter blade 5, and a shutter opening ring 4 is arranged around the opening 47 inside the opening ring 4 to control the opening of the shutter blade 5. a shutter opening ring control section 62 for controlling the rotational drive of the opening ring 4, a shutter closing ring control section 63 for controlling the rotational drive of the closing ring 3, and adjusting the opening speed of the shutter blades. It is composed of a speed regulating mechanism section 64 that charges the drive springs 13 and 14 in conjunction with the winding of the film.

The above shutter blade 5 (only two leaves are shown in the figure)
is rotatably supported at its base by a shaft 32 fixed to the shutter opening ring 4. The shutter closing ring 3 of this shutter blade 5
An elongated hole 5a is bored in a portion corresponding to the shutter closing ring 3, and an opening/closing pin 34 fixed to the shutter closing ring 3 is fitted into this elongated hole 5a.

The shutter opening ring 4 is adjacent to the outer side of the shutter closing ring 3, and both rings 3 and 4 are arranged concentrically and rotatably with respect to each other. A compressible drive spring 13 is applied to the pin 36 fixed to the shutter opening ring 4 and the pin 37 fixed to the cover plate 1, and the shutter opening ring 4 is moved by the spring. It is designed to be rotated clockwise. A notch 4a is provided on the periphery of the shutter opening ring 4, and a hook 6c of the shutter opening ring locking lever 6 constituting the shutter opening ring control section 62 engages with this notch 4a. The opening ring 4 is prevented from rotating clockwise by the tension of the spring 13. Further, on the shutter opening ring 4 opposite to the position where the notch 4a is provided, there are two protrusions 4c,
4d are formed with relatively narrow intervals, and a protrusion 3a protruding from the circumferential surface of the shutter closing ring 3 engages between the protrusions 4c and 4d. The rotational movement of the rings 3 and 4 is mutually restricted by this protrusion 3a and both protrusions 4c and 4d.

Further, a partial gear 4e is formed on a part of the circumferential surface of the shutter opening ring 4, and the pinion 29 of the speed regulating mechanism section 64 is attached to this partial gear 4e.
are meshing. Furthermore, a protrusion 4b is provided on the lower right peripheral surface of the shutter opening ring 4 (in FIG. 3), and this protrusion 4b is connected to the charge member 1 of the charge section 65.
8, the opening ring 4 is rotated counterclockwise in conjunction with film winding.

On the other hand, the shutter closing ring 3 has a compressible drive spring 1 hooked on a pin 38 fixed to the ring 3 and a pin 39 fixed to the cover plate 1.
4, the shutter is rotated in the clockwise direction, but in normal operation, the protruding portion 3a engages with the inclined edge 8c of the shutter closing ring locking lever 8 of the shutter closing ring control section 63. Thus, the closing ring 3 is prevented from rotating due to the elasticity of the spring 14.

The shutter opening ring control section 62 consists of a shutter opening ring locking lever 6 and a shutter opening control magnet Mg ₁ , which are arranged in a recess 1a formed in the lid plate 1. The locking lever 6 is formed in an inverted L-shape, and the fulcrum of its bent base 6e is rotatably supported on a support shaft 1d fixed to the cover plate body 1. A hook portion 6c is formed at the tip of the locking arm 6a extending in the vertical direction of the locking lever 6, and the hook portion 6c is configured to engage and disengage from the cutout portion 4a of the opening ring 4 at the appropriate time. The sloped edge 6d formed on the lower edge of the hook portion 6c is
The opening ring 4 contacts the lower step of the notch 4a.
It prevents the rotation of. The horizontally extending suction arm 6b of the locking lever 6 has a suction piece 73 which is swingably supported by a shaft 72 fixedly attached to the arm 6b, and is attracted to the magnet Mg ₁ . Lever 6
is held in the locked position of the ring 4.

When the locking lever 6 is rotated counterclockwise after the attraction force of the magnet Mg ₁ is lost,
The suction arm 6b comes into contact with the side wall 1g of the recess 1a formed in the cover plate 1, and is prevented from moving further away from the magnet _Mg1 . The distance between the adsorption arms 6b is the same as that of the magnet Mg ₁
This is the range within which the attractive magnetic force of the magnet acts.
The power to the coil 7 of Mg ₁ is cut off, and the permanent magnet 21
When the attracting magnetic force of Mg 1 is recovered, the attracting arm 6b within this range becomes a magnet Mg ₁ due to the attracting magnetic force.
It has become adsorbed by

The above shutter opening control magnet Mg ₁ is
It is constituted by a well-known release type magnet consisting of a permanent magnet 21, yokes 22a and 22b holding the permanent magnet 21 between them, and a coil 7 wound around one of the yokes 22a. This release type magnet is
When no current is flowing through the coil 7, the attracting arm 6b is attracted by the attracting magnetic force of the permanent magnet 21, the inclined edge 6d engages with the notch 4a of the ring 4, and the rotation of the ring 4 is prevented. Although it prevents
When a current flows through the coil 7, the magnetic force generated by this current cancels out the magnetic force of the permanent magnet 21, so the locking lever 6 becomes free.

The shutter closing ring control section 63 consists of a shutter closing ring locking lever 8 and a shutter closing control magnet Mg ₂ , and is formed in a recess formed in the right diagonal upper part of the lid plate body 1 (in FIG. 3). 1
It is located within b. The above-mentioned locking lever 8 is formed of a three-armed rod, and a fulcrum at a substantially central portion 8f thereof is rotatably supported by a support shaft 1e fixed to the cover plate body 1. A hook portion 8b is provided at the tip of the locking arm 8a extending obliquely downward to the left of the locking lever 8 (in FIG. 3). 8c is formed,
This inclined edge 8c abuts against the protrusion 3a of the closing ring 3 and prevents the closing ring 3 from rotating. A shaft 67 is fixed to the horizontally extending suction arm 8d of the locking lever 8, and a suction piece 6 is attached to the same shaft 67.
8 is rotatably supported. The attracting piece 68 is attracted to the magnet _Mg2 . Further, a braking arm 8e of the locking lever 8 that extends in the opposite direction to the locking arm 8a is located near an ankle 12, which will be described later.

The shutter closing control magnet Mg ₂ , like the magnet Mg ₁ described above, is formed of a release type magnet, and includes yokes 24a and 24b, and a permanent magnet 23 held between both yokes 24a and 24b.
The coil 9 is wound around one yoke 24a. When no current is flowing through the coil 9, the attraction piece 68 is attracted to the magnet Mg ₂ by the attraction magnetic force of the permanent magnet 23, and the inclined edge 8c of the hook portion 8b of the locking lever 8 is Contacting the protrusion 3a of the closing ring 3,
Rotation of the closing ring 3 is prevented. Furthermore, when current flows through the coil 9, the electromagnetic force is applied to the permanent magnet 23.
Since the attracting magnetic force of the locking lever 8 is canceled out, the locking lever 8 becomes completely free. When the locking lever 8 is also rotated counterclockwise, its suction arm 8d comes into contact with the side wall 1h of the recess 1b and is prevented from separating from the magnet Mg ₂ any further.

The speed regulating mechanism section 64 includes a concave portion 1 of the lid plate body 1.
A pinion 29 is disposed in the upper part (in FIG. 3) of the opening ring 4 and meshes with a partial gear 4e formed on the circumferential surface of the opening ring 4;
A gear 10 that rotates together with the pinion 29 around a support shaft 44 that is fixed concentrically with the pinion 9 and fixed to the cover plate body 1, a gear 30 that meshes with the gear 10, and a gear 30 that meshes with the gear 10. The gear 3
an escape wheel 11 that rotates together with the escape wheel 1; and a shaft 6 that engages with the escape wheel 11 and is fixed to the cover plate body 1.
When the partial gear 4e rotates due to the rotation of the opening ring 4, the rotation is transmitted through the pinion 29 to the gears 10, 30 and the escape wheel. 11. A pallet wheel 12 is engaged with the escape wheel 11 at appropriate times to keep the rotational speed of the escape wheel 11 constant. Therefore, the rotational speed of the opening ring 4 is kept constant by this speed regulating mechanism.

The charge portion 65 is disposed in a recess 1c provided at the lower left side of the lid plate body 1 (in FIG. 3). The charge part 65 includes a charge member 18 formed of a rectangular thin horizontally long plate member having a projection 18a, and a charge member 18 formed of a rectangular thin horizontally long plate member having a projection 18a.
and a compressible spring 15 hung on a pin 70 fixed to the cover plate body 1. The charge member 18 has a guide slot 18b in its longitudinal direction,
18c is bored, and the same long holes 18b and 18c
pins 40 fixed to the cover plate body 1, respectively.
41 is fitted. The spring 15 normally moves the charge member 18 to the left, and in connection with film winding, is moved to the right by a drive member (not shown), and when the film winding is completed,
It moves back to the left due to the elasticity of the spring 15. In connection with film winding, the charge member 1
8 moves to the right, the right end tip 18e of the charge member 18 touches the protrusion 4b of the opening ring 4.
, the opening ring 4 is rotated counterclockwise, and the drive springs 13 and 14 are charged.

In addition, as shown in FIG.
6, 27, and 28 are drilled. Screw holes (not shown) are also drilled at the same positions of the cover plate 2 corresponding to the three corners, and both cover plates 1,
When the two cover plates 1 and 2 are superimposed, the cover plates 1 and 2 are integrated with screws 71 to form a casing 46.
Furthermore, the lid plate body 1 has a notch 1 at its upper left corner.
f, and a hole 72 is bored in the lower right corner, and holes of the same shape and the same diameter are also provided in the same position of the cover plate body 2 corresponding to the above two corners. There is. When both the cover plates 1 and 2 are joined together, the holes 72 are filled with the holes 72, as shown in FIG.
A guide tube 25 is screwed on, and a guide pin 16 fixed to a fixed member of the camera is inserted into the guide tube 25, and a guide pin 17 fixed to a fixed member of the camera is also inserted into the notch 1f. be done. By moving the entire shutter housing housing 46 along the guide pins 16 and 17 in the optical axis direction of the lenses 19 and 20, the lenses 19 and 20 disposed in the housing 46,
20 focal lengths can be adjusted.

FIG. 7 shows an example of an electric shutter circuit for operating the shutter drive mechanism, in which a photovoltaic circuit is connected to both ends of the DC power source E via a power switch _SW0 that is closed in connection with the release operation of the shutter. Series circuit of conversion element P and capacitor C, resistance
A voltage dividing circuit of R ₁ and R ₂ , a series circuit of transistor Q ₁ and the above-mentioned shutter opening control magnet Mg ₁ ,
A series circuit of transistor Q ₂ and resistor R ₅ and a series circuit of transistor Q ₃ and the shutter closing control magnet Mg ₂ are connected, respectively.
Further, the comparator OP has its positive input terminal connected to the connection point between the resistors R ₁ and R ₂ , its negative input terminal connected to the connection point between the photoelectric conversion element P and the capacitor C, and its output terminal connected to the connection point between the resistors R 1 and R 2. ₃ and the base of _{the transistor Q 2 via} a resistor R ₄ . In addition, a normally closed trigger switch is installed at both ends of the capacitor C.
SW ₁ is connected, and the above transistor
The collector of Q ₂ is connected to the base of the above transistor Q ₃ .

The trigger switch SW ₁ opens in conjunction with the opening operation of the shutter, releases the short circuit of the capacitor C, and connects the photoelectric conversion element P to the capacitor C.
It is designed to charge the current that passes through it. The photoelectric conversion element P measures the reflected light from the subject to be photographed, and charges the capacitor C with a current proportional to the subject light. Comparator OP above
receives the voltage charged in the capacitor C at its negative input terminal, and compares the charged voltage with the reference voltage created by the voltage divider circuit of the resistors R ₁ and R ₂ applied to its positive input terminal. However, when the reference voltage is higher than the charging voltage, the output terminal of the comparator OP is set to high level and transistors Q ₁ and Q ₂ are turned on. However, when the charging voltage is higher than the reference voltage, the output terminal of the comparator OP is set to high level. It becomes a low level and turns off transistors Q ₁ and Q ₂ .

Next, the operation of the two-ring type lens shutter of the present invention will be explained with reference to FIGS. 3 to 7.

FIG. 3 shows the notch 4 of the opening ring 4 after the film has been wound and the shutter has been charged.
The figure shows a state in which the hook portion 6c of the locking lever 6 is engaged with the point a, thereby restraining the rotational movement of the opening ring 4. In this state, the protruding portion 3a of the closing ring 3 also connects to the hook portion 8 of the locking lever 8.
b, and prevents the rotation of the closing ring 3.

Now, in this state, when you press the camera's shutter button and release the shutter, the power switch SW ₀ shown in Figure 7 closes, and the power supply voltage is supplied to the electric circuit shown in Figure 7. do. At this point, the trigger switch _SW1 is still closed, so the charging voltage of the capacitor C is zero. Therefore, the output terminal of the comparator OP is at a high level, and the high level output signal of the comparator OP causes the transistors Q ₁ and Q _{2 to}
is on and transistor _Q3 is off. When the transistor _Q1 is turned on, current flows through the coil 7 of the shutter opening control magnet _Mg1 . Further, since the transistor _Q3 is off, no current flows through the coil 9 of the shutter closing control magnet _Mg2 .

When a current flows through the coil 7 of the magnet Mg ₁ , the attractive magnetic force of the permanent magnet 21 is eliminated and the shutter opening ring locking lever 6 becomes free.
The shutter opening ring 4 begins to rotate clockwise due to the compressed elasticity of the drive spring 13, causing the shutter blade 5 to rotate around the pin 34, thereby starting the shutter opening operation. When the shutter starts to open, the trigger switch SW ₁ shown in Figure 7
opens, and the capacitor C begins to be charged via the photoelectric conversion element P.

When the shutter opening ring 4 begins to rotate clockwise, its notch 4a will open as shown in FIG.
The inclined edge 6d of the locking lever 6 that was in contact with the notch 4a is pushed by the edge of the notch 4a, and the hook portion 6c of the locking lever 6 is disengaged from the notch 4a, and the hook 6c of the locking lever 6 disengages from the notch 4a. Move to a position where it does not interfere with the rotation of the opening ring 4. At this time, the lower edge of the tip of the suction arm 6b of the locking lever 6 is connected to the side wall 1 of the recess 1a.
g, and restricts the locking lever from rotating any further. As mentioned above, this is
This is to position the attracting arm 6b within the range of the attracting magnetic force of the magnet _Mg1 .

When the shutter opening ring 4 rotates, the pinion 29 that meshes with the partial gear 4e formed on its outer circumferential surface rotates, and the aforementioned speed regulating mechanism 64 causes the
The rotational speed of the ring 4 becomes constant, and the opening degree l of the shutter also becomes constant, as shown in FIG.

Returning to FIG. 7, the charging voltage of capacitor C gradually increases and exceeds the reference voltage at the appropriate shutter time, so the output terminal of comparator OP goes from high level to low level, and transistors Q ₁ , Turns off Q ₂ and turns on transistor Q ₃ . When transistor Q ₃ turns on,
A current flows through the coil 9 of the shutter closing control magnet Mg ₂ , and the attracting magnetic force of the permanent magnet 23 of the shutter closing control magnet Mg ₂ is eliminated, and the shutter closing ring locking lever 8 becomes free. Then, the opening ring 3 rotates clockwise due to the tightening elasticity of the drive spring 14, and the protrusion 3a of the ring 3 pushes away the inclined edge 8c of the locking lever 8, and as shown in FIG. The hook portion 8b of the locking lever 8 is retracted from the rotation path of the protruding portion 3a, and the locking lever 8
rotates counterclockwise around the support shaft 1e. When this rotates, the tip of the control arm 8e of the locking lever 8 comes into contact with the pallet 12 of the speed regulating mechanism 64 and presses the pallet 12, so the operation of the synchronizing mechanism 64 is stopped and the opening ring 4 Partial gear 4e
The rotational movement of the opening ring 4 is braked via the pinion 29 which meshes with the opening ring 4. Further, the tip of the suction arm 8d of the locking lever 8 is connected to the side wall 1h of the recess 1b.
The suction arm 8d does not move any further.
This is to position the attracting arm 8d within the range where the attracting magnetic force of the permanent magnet 23 of the magnet Mg ₂ acts.

Furthermore, when the transistor Q ₁ is turned off, the current to the coil 7 of the magnet Mg ₁ is cut off, so that the attracting magnetic force of the permanent magnet 21 of the magnet Mg ₁ is restored, and the locking force within the range of this attracting magnetic force is Pull the suction arm 6b of the lever 6 toward the magnet Mg ₁ . Then, as shown in FIG. 5, the tip of the hook portion 6c of the locking lever 6 comes into contact with the circumferential surface of the opening ring 4, so the locking lever 8 cannot rotate any further, but the suction A tension force that pulls the attracting arm 6b toward the magnet Mg ₁ is applied to the arm 6b due to the attracting magnetic force of the magnet Mg ₁ , and the opening ring 4
The rotational movement of the opening ring 4 is braked by the hook portion 6c which is in contact with the circumferential surface of the opening ring 4. That is,
By the braking means of the present invention, the brake by the speed regulating mechanism section 64 and the brake by the hook part 6c of the locking lever 6 act simultaneously on the opening ring 4, and the rotational movement of the opening ring 4 is controlled. , the brakes are completely applied.

Transistor Q ₃ turns on and the magnet
When the attraction magnetic force of Mg ₂ disappears and the shutter closing ring 3 starts rotating clockwise, at this time,
As mentioned above, since the opening ring 4 is braked and is stationary, the shutter blade 5 is rotated counterclockwise around the shaft 32 by the pin 34 fixed to the closing ring 3. direction, and the shutter blade 5 begins to rapidly close. Then, the rotation of the closing ring 3 progresses, and its protrusion 3a
When the shutter blade 5 comes into contact with the protrusion 4c of the opening ring 3, the shutter blade 5 is completely closed, as shown in FIG.
The shooting ends here.

Then, when the shutter closes and the shutter button is restored, the power switch SW ₀ in Fig. 7 opens.
Trigger switch SW ₁ closes and returns to the initial state. Also, after that, when the film is wound,
In conjunction with this, the charge member 18 is pushed to the right, so the protruding portion 4b of the opening ring 4 is pushed and the opening ring 4 is rotated counterclockwise. At this time, the protruding part 3a of the closing ring 3 is also pushed by the protruding part 4c of the opening ring 4, and rotates counterclockwise together. Then, the hook portion 6c of the locking lever 6 engages with the notch portion 4a of the opening ring 4. When the film winding is completed and the charging member 18 returns to its original position, the opening ring 4 tries to rotate clockwise due to the elasticity of the charged drive spring 13, but the opening ring 4 tries to rotate clockwise due to the elasticity of the charged drive spring 13. sloped edge 6
d comes into contact with the edge of the notch 4a to prevent its rotation and return to the state shown in FIG. 3.

As mentioned above, the shutter of the present invention operates.This operation will now be explained in detail with reference to Fig. 1.In Fig. 1, at time _t1 , the closing ring 3
When the shutter blade 5 starts to rotate and the shutter blade 5 starts to close, the opening degree l of the shutter starts to decrease from this point on. In this case, if there is no brake provided by the speed regulating mechanism 64 according to the present invention and no brake provided by the locking lever, the opening ring 4 will continue to rotate as described above, so the opening degree l of the shutter will change over time. At time t ₃ , it finally becomes completely zero, but if the above-mentioned brakes according to the present invention are applied, the shutter opening degree l becomes completely zero at time t ₂ , compared to the case where no brake is applied. The excess opening amount can be reduced by the hatched opening amount in FIG. 1, and overexposure can be reduced.

Therefore, according to the present invention, the governor of the speed regulating mechanism section 64 connects the gears 10 and 30 via the pinion 29.
Since the speed is increased and transmitted to the escape wheel 11, a large braking action can be performed with a small torque. In addition, since the pallet wheel 12 changes rotational motion to rocking motion,
By abutting and pressing the tip of the control arm 8e against this, the governor can be reliably stopped.
A reliable braking action can be applied to the release ring 4. Furthermore, it is possible to provide a two-ring type lens shutter that completely eliminates the drawbacks of conventional shutters of this type as described at the beginning of the specification.

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram showing the opening amount of a two-ring type lens shutter versus time, Fig. 2 is a sectional view of a two-ring type lens shutter showing an embodiment of the present invention, and Fig. 3 The figure is a front view showing the shutter mechanism housed in the shutter storage case shown in Fig. 2 above, Figures 4, 5, and 6 are front views showing the operating mode of the shutter mechanism shown in Fig. 3 above, and Fig. 7 This figure is a diagram showing an electric shutter circuit used in the two-ring type lens shutter shown in FIG. 3 above. 3... Shutter closing ring, 4... Shutter opening ring, 5... Shutter blade, 8a... Locking member, 8e... Control member, 11... Escape wheel, 1
2...Ankle, 64...Governing mechanism.

Claims (1)

[Scope of claim for utility model registration] Rotating by the release operation of the shutter,
A shutter opening ring that performs the opening operation of the shutter blades, a speed governing mechanism that engages with the shutter opening ring and has an escape wheel and pallets that keep the speed of the opening operation of the shutter blades constant; A shutter closing ring that performs the closing operation is engaged with this shutter closing ring to lock this rotation, and when the exposure time has elapsed, it moves from the engaged position and allows the shutter closing ring to rotate. A two-ring lens shutter comprising: a locking member; and a braking member pressed against the ankle of the speed regulating mechanism in conjunction with movement of the locking member.