JPS62485B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camera shutter using a release type magnet, and more particularly, a locking member that engages with and disengages from a shutter opening/closing control ring to control the drive of the ring, and a locking member that controls the operation of the shutter opening/closing control ring. This invention relates to a two-ring type camera shutter having a release type magnet for control.

A two-ring type lens shutter using a release type magnet 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.
The rotation of both rings is controlled by a shutter ring locking lever operated by a release type magnet.

Next, we will explain the drive control mechanism using a release type magnet for the shutter opening/closing control ring in this kind of conventional lens shutter.As shown in FIG. An inverted L-shaped shutter opening ring locking lever 6 is provided.

This locking lever 6 has its swinging fulcrum on a support shaft 1d.
On the suction arm 6b, which is pivotally mounted on the shutter and extends horizontally, there is a magnet for controlling the shutter opening.
The suction piece 73 that attracts and separates Mg ₁ is the shaft 72
It is attached so that it can swing freely. A hook portion 6c protruding toward the shutter opening ring 4 is provided at the tip of the locking arm 6a extending in the vertical direction of the locking lever 6, and the lower edge thereof has an inclined edge. 6d is formed. The locking lever 6 formed in this manner is rotated clockwise around the support shaft 1d by a compressible coil spring 50 stretched between a pin 52 fixed to the suction arm 6b and an immovable pin 51. Due to this rotation, the suction piece 73 is brought into contact with the shutter opening control magnet Mg ₁ , and the hook portion 6c is brought into contact with the periphery of the shutter opening ring 4. It is adapted to be engaged in a timely manner with a notch 4a provided in a part of.

The shutter opening ring 4 is rotated clockwise by a driving spring 13 having tension elasticity, which is stretched between a pin 36 fixed on the ring 4 and a pin 37 fixed on an immovable member. to open the shutter blade, but in normal life, the above magnet
When the locking lever 6 is attracted to the Mg ₁ , the hook portion 6c enters the notch portion 4a, and the inclined edge 6d engages with the hook portion 6c, thereby rotating the ring 4 in the clockwise direction. is being prevented.

The above shutter opening control magnet Mg ₁ is
A permanent magnet 21 is held between yokes 22a and 22b,
It is composed of a well-known open type magnet in which a coil 7 is wound around one yoke 22a, and during normal operation when no excitation current is flowing through the coil 7, the permanent magnet 2
Although the attraction arm 6b is attracted through the attraction piece 73 by the attraction magnetic force of 1 and restrained, the coil 7
When an excitation current flows through and excites the electromagnet consisting of a yoke and a coil in a direction that demagnetizes the attracting magnetic force of the permanent magnet 21, the attracting arm 6b is released from its restraint and becomes free.

The magnet Mg ₁ has the following characteristics when the shutter button is pressed and the shutter is released:
An excitation current for demagnetization is passed through the coil 7. When this current is applied, the attractive magnetic force of the permanent magnet 21 is demagnetized as described above, and the ring 4 is moved clockwise by the tightening elasticity of the drive spring 13 against the elasticity of the spring 50. Rotate. Then, the locking lever 6 has its inclined edge 6d pushed by the ring 4, the hook portion 6c is pushed out from within the notch 4a, and rotates counterclockwise around the support shaft 1d, and the locking lever 6 is rotated counterclockwise around the support shaft 1d. The notch 4a and the inclined edge 6d are disengaged from each other.

When the ring 4 rotates clockwise, a shutter blade (not shown) opens and the film surface is exposed through the photographing lens 19. When the proper exposure time has elapsed, the shutter closing ring 3 is rotated clockwise by a control member (not shown) to close the shutter blades. When the shutter operation is completed, the current to the coil 7 of the magnet Mg ₁ is cut off, so that the attractive magnetic force of the permanent magnet 21 is restarted. A charge member (not shown) operates in conjunction with the winding of the film, and this operation causes the ring 4 to rotate counterclockwise against the elasticity of the spring 13. Then, the hook portion 6c of the locking lever 6 is attached to the ring 4.
The ring 4 returns to the initial state in which the drive spring 13 is charged by protruding into the notch 4a and the slanted edge 6d of the hook 6c engaging with the notch 4a. That is, when the notch portion 4a rotates and comes to a position corresponding to the hook portion 6c, the locking lever 6 rotates clockwise due to the elasticity of the spring 50, so that the hook portion 6c is rotated. enters into the notch 4a. Then, the attraction piece 6b of the lever 6 comes into contact with the magnet _Mg1 , and is attracted to the magnet by the attraction magnetic force of the magnet. Therefore, the inclined edge 6d of the hook portion 6c is held at the position where it engages with the notch portion 4a, and the clockwise rotation of the ring 4 is prevented.

In the spring 50, the ring 4 rotates counterclockwise in a double direction, and the cutout portion 4a of the spring 50 is connected to the hook portion 6c.
When the lever 6 is at the position where it engages with the hook part 6, rotate the lever 6 clockwise around the support shaft 1d to release the hook part 6.
c is inserted into the notch 4a to engage the two. That is, at this time, as mentioned above, since the current to the coil 7 of the magnet Mg ₁ is cut off, the attracting magnetic force of the permanent magnet 21 is acting on the attracting arm 6b; The attracting magnetic force is not strong enough to attract the attracting piece due to the distance between the attracting arm 6b and the magnet Mg ₁ , so the lever 6 cannot be moved by the attracting magnetic force alone. This spring 50 is provided because the hook portion 6c cannot be thrust into the notch portion 4a by rotating clockwise around the support shaft 1d.

By the way, in the conventional drive control mechanism configured as described above, the spring 50 constantly applies a force to the locking lever 6 to rotate the lever 6 clockwise, so that the shutter is released.
Even when the attracting magnetic force of the magnet Mg ₁ is demagnetized and the ring 4 is about to rotate clockwise, the force of the spring 50 causes the inclined edge 6d of the hook portion 6c of the lever 6 to move around the ring 4. It collides with the notch 4a, becomes a load, and makes the rotation start timing of the ring 4 unstable. Further, even while the ring 4 is rotating, the hook portion 6 of the lever 6
The tip of c comes into contact with the circumferential surface of the ring 4 and acts as a brake, slowing down or making the rotation of the ring 4 unstable.

Therefore, in order to eliminate such drawbacks, the second
As shown in the figure, a compressible spring 53 is stretched between a pin 54 fixed on the suction arm 6b of the locking lever 6 and a pin 55 fixed on a stationary member (not shown). What is necessary is just to configure it so that rotational force is applied in a counterclockwise direction.

In this way, the spring 53 applies a counterclockwise rotational force to the locking lever 6, so that the release type magnet
When a current flows through the Mg ₁ coil 7 and the attractive magnetic force of the permanent magnet 21 is demagnetized, the lever 6 immediately rotates counterclockwise. Then, the inclined edge 6d of the hook portion 6c of the lever 6 immediately separates from the cutout portion 4a of the shutter opening ring 4, so that the ring 4 is smoothly rotated clockwise by the elasticity of the spring 13. In this case, the hook portion 6c and the inclined edge 6d of the lever 6 are completely separated from the cutout portion 4a and the circumferential surface of the ring 4, so that the hook portion 6c and the inclined edge 6d of the lever 6 are completely separated from the notch portion 4a and the circumferential surface of the ring 4, so that the hook portion 6c and the inclined edge 6d of the lever 6 are completely separated from the notch portion 4a and the circumferential surface of the ring 4. The rotation start timing of ring 4 will no longer become unstable and the rotation of ring 4 will no longer become a brake.

However, if the drive mechanism is configured as shown in FIG.
is separated from the magnet Mg ₁ , so even if the coil 7 is de-energized and the attraction magnetic force of the permanent magnet 21 is restarted, the attraction arm 6b will not be attracted to the magnet Mg ₁ by this magnetic force alone. . Therefore,
In this case, in conjunction with the film winding in preparation for the next photograph, the locking lever 6 is rotated clockwise against the force of the spring 53, and the suction arm 6b is attached to the magnet Mg _1. A charge mechanism is required to bring it into contact and attract it.

It is an object of the present invention, in order to eliminate the above-mentioned drawbacks of the conventional art, to have a shutter that is attracted by the attraction magnetic force of a release type magnet and engaged with a shutter opening/closing control ring.
To provide a shutter for a camera using a release type magnet, in which a locking member that prevents rotation of the ring limits the range of movement when the attracting magnetic force of the magnet is erased to within the range of the attracting magnetic force of the magnet. There is something to do.

According to the present invention, the moving range of the locking member that is attracted by the magnetic force of the release type magnet, engages with the shutter opening/closing control ring, and stops the rotation of the ring is controlled by the magnetic force of the magnetic force of the magnet. Since the locking member is limited within the range, a spring is not required to move the locking member back to the position where it is attracted to the magnet. Therefore, due to the action of this spring, the locking member is constantly subjected to a pushing force and comes into contact with the ring, making the rotation start of the ring unstable or applying a brake to the rotational movement of the ring. drawbacks are completely eliminated.

In addition, when the attraction magnetic force of the release type magnet is eliminated, the locking member becomes completely free, so it does not affect the start and rotation of the ring, and therefore allows the opening and closing ring to be moved accurately. can be operated. Furthermore, since there is no need for a spring to disengage the locking member from the ring, there is no need for a charge mechanism for this purpose.

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

In FIG. 3, a shutter housing casing 46 that houses the shutter mechanism is formed by overlapping two lid plates 1 and 2 with side walls with their openings facing each other. ing. Further, when both the cover plates 1 and 2 are separated, the interior of each cover plate 1 and 2 is exposed. As shown in FIG. 4, inside the upper cover plate body 1, there is a shutter closing ring 3, a shutter opening ring 4, a shutter blade 5, which is housed in the housing 46, and a shutter opening which is a locking member. Ring locking lever 6, magnet Mg ₁ for shutter release control,
Shutter closing ring locking lever 8, shutter closing control magnet Mg ₂ , gear 10,
30, pinion 29, escape wheel 11, ankle 1
2, charge member 18, drive springs 13, 14, 1
A shutter mechanism such as No. 5 is mainly housed therein, and the lower cover plate 2 serves to cover the upper cover plate 1. In addition, the cover plate bodies 1 and 2
As shown in FIG. 3, circular openings 47 and 57 are provided in the center of the openings 47 and 57, respectively, to form optical paths for photographing. Step portions 58 and 59 are provided for attaching lenses 19 and 20 for use. Photographing lenses 19 and 20 are fixed to the stepped portions 58 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 a shutter opening ring locking lever 6 constituting the shutter opening ring control section 62 is engaged 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 is engaged between the protrusions 4c and 4d. The rotational movement of the rings 3 and 4 is mutually limited 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 protruding portion 4b is provided on the lower right peripheral surface of the shutter opening ring 4 (in FIG. 4), and this protruding portion 4b is connected to the charge member 1 of the charge portion 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. The closing ring 3 is thus prevented from rotating by the force 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 hole 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
Similar to the conventional one, a permanent magnet 21, yokes 22a and 22b that sandwich the permanent magnet 21,
It is composed of a release type magnet consisting of a coil 7 wound around one yoke 22a.

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. 4). 1
It is located within b. The 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. 4). 8c is formed, and this inclined edge 8c is the protrusion 3 of the closing ring 3.
a, and prevents the rotation of the closing ring 3. The horizontally extending suction arm 8 of the locking lever 8
A shaft 67 is fixedly planted at d, and an adsorption piece 68 is pivotally supported on the same shaft 67. And the same suction piece 68
is adsorbed on the above magnet Mg ₂ . Further, a braking arm 8e of the locking lever 8 extending in a direction opposite to the locking arm 8a is connected to a pallet lever 1 which will be described later.
It is located close to 2.

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 hole 1b and is prevented from separating from the magnet Mg ₂ any further.
The reason for this is the same as the reason for the magnet Mg ₁ mentioned above.

The speed regulating mechanism section 64 includes a concave portion 1 of the lid plate body 1.
a pinion 29 disposed in the upper part (in FIG. 4) of the opening ring 4 and meshing with a partial gear 4e formed on the circumferential surface of the open 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 gear. It is transmitted to the car 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. 4). 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 2 are superimposed, both cover plates 1 and 2 are integrated with screws to form a casing 46. Furthermore, the lid plate body 1 has a notch 1f at its upper left corner.
A hole 72 is bored in the lower right corner, and holes of the same shape and the same diameter are also provided at the same positions on the cover plate body 2 corresponding to the two corners. . When both the cover plates 1 and 2 are joined together, the guide tube 25 is screwed into the hole 72, as shown in FIG. 3, and the guide pin 16 is inserted through the guide tube 25. Further, the guide pin 17 is also inserted through the notch 1f. Then, the entire shutter storage case 46 is connected to this guide pin 1.
The focal lengths of the lenses 19, 20 disposed in the housing 46 are adjusted by moving the lenses 19, 20 in the optical axis direction along the lenses 6, 17.

FIG. 8 is an example of an electric shutter circuit for operating the shutter drive mechanism. A power switch SW ₀ is connected to both ends of the DC power supply E, which is closed in connection with the shutter release operation.
A series circuit of photoelectric conversion element P and capacitor C, a voltage dividing circuit of resistors R ₁ and R ₂ , a series circuit of transistor Q ₁ and the above-mentioned shutter open control magnet Mg ₁ , a series circuit of transistor Q ₂ and resistor R ₅ , a transistor Q ₃ is connected to the series circuit of the shutter closing control magnet Mg ₂ , and a comparator OP has its positive input terminal connected to the connection point of the resistors R 1 and R 2, and its negative input terminal connected to the connection point of the resistors R ₁ and R ₂ . The photoelectric conversion element P is connected to the connection point of the capacitor C, and its output terminal is connected to the base of the transistor _Q1 and the resistor via the resistor _R3 .
These are connected to the bases of the transistor Q ₂ via R ₄ respectively. A normally closed trigger switch _SW1 is connected to both ends of the capacitor C, and the collector of the transistor _Q2 is connected to the base of the transistor _Q3 .

The trigger switch _SW1 is opened in conjunction with the opening operation of the shutter, disconnecting the capacitor C and charging the capacitor C with the current passing through the photoelectric conversion element P. 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 above
OP receives the voltage charged in the above capacitor C at its negative input terminal, and the reference voltage created by the voltage divider circuit of the above resistors R ₁ and R ₂ applied to its positive input terminal and the above charging voltage. and when the reference voltage is greater than the charging voltage, the comparator
Set the output terminal of OP to high level and connect the transistor
Q ₁ and Q ₂ are turned on, but when the charging voltage becomes higher than the reference voltage, the output terminal of the comparator OP becomes a low level, turning off the transistors Q ₁ and Q ₂ .

Next, the operation of the camera shutter of the present invention will be explained with reference to FIGS. 4 to 8.

FIG. 4 shows the notch 4 of the opening ring 4 when the film winding is completed and the shutter is 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 comes into contact with the inclined edge 8c of the hook portion 8b of the locking lever 8, thereby preventing the closing ring 3 from rotating.

Now, in this state, when you press the camera's shutter button to release the shutter, the power switch SW ₀ shown in Figure 8 closes, and the power supply voltage is supplied to the electric circuit shown in Figure 8. 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, a 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 8 is activated in conjunction with the shutter opening.
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. The engaging portion 4g is moved to a position where it does not interfere with the rotation of the opening ring 4. At this time, the lower edge of the distal end of the suction arm 6b of the locking lever 6 comes into contact with the stopper 1g, which is the side wall of the recess 1a, thereby restricting the locking lever from rotating any further. This is because, as described above, the attracting arm 6b is located 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. FIG. 9 is a characteristic diagram showing the shutter opening degree l versus time t. In Figure 9, the shutter opening degree l
increases linearly in proportion to time t, and reaches the opening degree l ₀ when the shutter is fully open.

Returning to FIG. 8, 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 , 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 closing 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 section 64 and presses the pallet 12, so that the synchronized speed mechanism section 6
4 is stopped, and the rotational movement of the opening ring 4 is braked via the pinion 29 meshing with the partial gear 4e of the opening ring 4. In addition, the locking lever 8
The tip of the suction arm 8d contacts the stopper 1h, which is the side wall of the recess 1b, and the suction arm 8d
does not move. 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 . However, in this case, as shown in FIG. 6, the tip of the hook portion 6c of the locking lever 6 comes into contact with the holding portion 4g on the circumferential surface of the opening ring 4.
The locking lever 8 cannot be rotated any further. However, the attraction arm 6b moves toward the magnet Mg ₁ due to the attraction magnetic force of the magnet Mg ₁ .
A tensile force is applied to the opening ring 4, and the rotational movement of the opening ring 4 is braked by the hook portion 6c that is in contact with the circumferential surface of the opening ring 4. That is, open ring 4
At this time, the brake from the speed regulating mechanism section 64 and the brake from the hook section 6C of the locking lever 6 act simultaneously, and the rotational movement of the opening ring 4 is completely braked.

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 starts the action of closing the shutter blade 5. and,
As the rotation of the closing ring 3 progresses and its protrusion 3a comes into contact with the protrusion 4c of the open ring 4, the shutter blade 5 closes as shown in FIG. 7, and photographing ends here.

Then, when the shutter closes and the shutter button is restored, the power switch SW ₀ in Fig. 8 opens.
Trigger switch SW ₁ closes and returns to the initial state. Further, when the film is wound up thereafter, the charge member 18 is pushed to the right in conjunction with this, so the protrusion 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 notch 4a of the open ring 4
The hook portion 6c of the locking lever 6 engages with the locking lever 6. 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. The inclined edge 6d contacts the edge of the notch 4a to prevent its rotation, returning to the state shown in FIG. 4.

In FIG. 9, time _t1 is the point at which the closing ring 3 begins to rotate and the shutter blade 5 is about to start its closing operation, and from this point on, the opening degree l of the shutter starts to decrease. If there is no brake by the speed regulating mechanism 64 and brake by the locking lever as described above, the opening ring 4 will continue to rotate, and the opening degree l of the shutter will decrease.
finally becomes completely zero at time t ₃ , but when both of the above brakes are applied, the shutter opening l becomes completely zero at time t ₂ , compared to the case where no brake is applied. , the extra opening amount is reduced by the opening amount indicated by diagonal lines in FIG.

As described above, according to the present invention, it is possible to provide a camera shutter in which the drawbacks of conventional shutter drive mechanisms using release type magnets have been completely eliminated.

[Brief explanation of the drawing]

Figures 1 and 2 are partial front views showing the main parts of a conventional camera shutter using a release type magnet, and Figure 3 is a camera shutter using a release type magnet showing an embodiment of the present invention. FIG. 4 is a front view showing the shutter mechanism housed in the shutter storage case shown in FIG. 3, and FIGS. 8 is a circuit diagram of an electric shutter used in the camera shutter shown in FIG. 3, and FIG. 9 is a characteristic diagram showing the opening amount of the shutter shown in FIG. 3. 1, 2... Lid plate body, 1g, 1h... Stopper (side wall), 3, 4... Shutter drive member (opening/closing ring), 3a, 4a... Engaging portion, 3g, 4g...
...Holding part, 5... Shutter blade, 6, 8... Locking member (locking lever), 7, 9... Coil, 2
1, 23...Permanent magnet, Mg ₁ , Mg ₂ ...Release type electromagnet.

Claims (1)

[Scope of Claims] 1. A release type electromagnet consisting of a permanent magnet and a coil that generates magnetic force in a direction that cancels the magnetic force of the permanent magnet when energized; a position attracted to the electromagnet; a locking member that is movable between separate positions; a stopper that limits the amount of separation of the locking member to a position that is attracted by the permanent magnet; and a shutter drive member that is biased in a direction to operate the shutter blade. and an engaging portion provided on the driving member that engages with the locking member when the locking member is in the adsorption position and disengages when the locking member is in the separated position; 1. A camera shutter using a release type magnet, comprising a holding part provided on the member and holding the locking member in a separated position when the driving member moves in a direction for operating the shutter.