JP3990080B2 - Shutter device for film unit with lens - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shutter device for a lens-fitted photo film unit provided with a delay mechanism for securing a time necessary for switching a diaphragm.
[0002]
[Prior art]
As a type of simple camera, a simple filming mechanism such as a photographing lens and shutter mechanism is built in, and various types of lens-fitted photo units with pre-loaded photographic films are sold by the present applicant, and users have good image quality. It is possible to take print photos easily. In this lens-fitted photo film unit, a fixed aperture opening is used in order to simplify the structure and reduce the cost. For this reason, the F value of the photographing lens is constant, and overexposure or underexposure may occur depending on the photographing conditions.
[0003]
This problem can be solved by incorporating a mechanism for changing the aperture diameter according to the amount of light of the subject, but a complicated structure leads to high costs, and thus cannot be introduced into a simple camera such as a film unit with a lens. In Japanese Patent Laid-Open No. 9-5817, therefore, a diaphragm plate having an aperture smaller in diameter than a fixed diaphragm aperture, photometric means for measuring a subject light amount, and outputting a switching signal when the light amount is a predetermined value or more, An automatic exposure control device having an electromagnet that operates when a switching signal is output has been proposed. In this automatic exposure control device, when the electromagnet is operated, a magnetic attraction force is generated between the diaphragm plate and the electromagnet, and the diaphragm diameter can be switched by moving the diaphragm plate against the bias of the spring. .
[0004]
[Problems to be solved by the invention]
However, in the above mechanism, photometry is performed when the shutter button is half-pressed, and the aperture plate is switched when the shutter button is fully pressed. Since it takes about 10 ms to switch the aperture, exposure may be performed before the switching of the aperture is completed. In this case, some or all of the external light that should normally be exposed is blocked, resulting in underexposure resulting in very poor image quality or, in the worst case, unexposed photographs. There is.
[0005]
When the lens-equipped film unit having the above mechanism is carried in a bag, the convex object in the bag comes into contact with the shutter button of the lens-equipped film unit, and the shutter button is half-pressed. There is a case. In this case, the lens-fitted photo film unit performs photometry, and depending on the result, the electromagnet may be energized. At this time, the battery is consumed wastefully, which becomes a fatal problem in the lens-fitted photo film unit in which the battery cannot be replaced. Furthermore, since the solenoid inside the electromagnet is excessively heated by energization for a long time, there is a possibility of causing ignition, and there is a problem from the viewpoint of safety.
[0006]
The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a shutter device for a lens-fitted photo film unit that can reliably switch the aperture while preventing wasteful battery consumption. .
[0007]
[Means for Solving the Problems]
The present invention is used together with an aperture switching unit that switches an aperture according to a photometric signal from a photometric unit that measures subject brightness, and when the shutter button is pressed, the shutter lever is biased by a spring to release the charging position. In a shutter device used in a lens-fitted photo film unit that is pre-loaded with a photographic film that operates by a kick-off method in which the shutter blades are kicked to open and close during the movement. Is released, rotates while holding the shutter lever in the charging position, and releases the holding of the shutter lever by rotating to a certain position to allow the movement to the release position, and operates the photometry means Metering switch and delay lever rotation In conjunction with this, the switch pressing member that turns on the photometric switch before the delay lever rotates to the predetermined position, and the rotation speed of the delay lever is adjusted, and the aperture is switched by the aperture switching means after the switch pressing member turns on the photometric switch. And a speed control mechanism for preventing the delay lever from rotating to a certain position until the switching is completed.
[0008]
The speed control mechanism is preferably a governor mechanism including an escape wheel that meshes with a gear formed on a delay lever, and an ankle that engages with the escape wheel and adjusts the rotation speed of the escape wheel. Moreover, it is preferable that the switch pressing member is integrally attached to the escape wheel. It is preferable that the time from when the photometric switch is turned on until the delay lever reaches the fixed position is 10 ms to 60 ms.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a film unit with a lens, which is a kind of simple camera, will be described as an example. As shown in FIG. 1, the lens-fitted photo film unit includes a unit main body 10 and an exterior label 11 that is wound around the outer periphery of the unit main body 10. On the front surface of the unit main body 10, a photographing lens 12, a finder 13, a strobe light emitting unit 14, a strobe switch 15, and a light receiving element 16 are provided. A shutter button 17, a film counter 20, and a charging completion confirmation window 21 are provided on the upper portion of the unit main body 10, and a part of the winding knob 22 is exposed to the outside on the back.
[0011]
As shown in FIG. 2, the unit main body 10 includes a main body base 23, an exposure unit 24, a strobe unit 25, a cartridge main body 26, a photographic film 27, and a front cover 30 and a rear cover 31 that cover these. The main body base 23 includes an exposure frame 32 for determining an exposure range of the photographic film 27, a cartridge storage chamber 33 for storing the cartridge main body 26, and a photographic film 27 drawn out from the cartridge storage chamber 33 and wound in a roll shape. It comprises a photo film storage chamber 34 for storing. A winding knob 22 is attached to the upper part of the cartridge storage chamber 34. A shaft (not shown) provided at the lower portion of the winding knob 22 is engaged with a spool 26a formed on the cartridge body 26, and one end of the photographic film 27 is sandwiched between slits formed on the spool 26a. Is held. For this reason, when the winding knob 22 rotates counterclockwise in the figure, the spool 26a also rotates in the same direction, and at the same time, the photographic film 27 moves to the left in the figure.
[0012]
The front cover 30 is provided on the front surface of the main body base 23, and has an opening that exposes the photographing lens 12, the finder 13, and the like to the outside. The rear cover 31 is provided behind the main body base 23 and covers the inside of the unit main body 10 together with the front cover 30 in a light-tight manner. Bottom covers 35a and 35b are integrally formed on the rear cover 31, and lightly cover the bottoms of the cartridge body 26 and the photographic film 27. Further, the bottom cover 35a is opened when taking the photographed cartridge body 26 out.
[0013]
The strobe unit 25 is disposed beside the exposure unit 24, and includes a printed circuit board 36 on which a strobe circuit is formed, a strobe light emitting unit 14, a capacitor 37, a battery 38, and a sync switch 40 attached thereto. Yes. The strobe circuit is a circuit for charging a capacitor with a charge necessary for causing the strobe light emitting unit 14 to emit light, and operates by depressing a push switch 41 provided on the printed circuit board 36. The strobe switch 15 is provided to be movable up and down in order to switch on and off the strobe circuit. When the strobe switch 15 is moved upward in the figure, the push switch 41 is pushed down, the strobe circuit is activated, and the capacitor 37 is charged. When the charging of the capacitor 37 is completed, the light emitting diode provided in the charging completion confirmation window 21 blinks. Thereafter, when the shutter button 17 is depressed, the sync switch 40 is closed and the strobe light is emitted from the strobe light emitting unit 14.
[0014]
The exposure unit 24 is attached to the front surface of the main body base 23. As shown in FIG. 3, the exposure unit 24 includes a dark box 42, a shutter cover 43, shutter blades 44, a diaphragm plate 45, and an electromagnet 46. A shutter opening 47 that guides subject light to the inside of the exposure frame 32 is formed at the center of the dark box 42, and a finder 13, a shutter lever 50, and the like are attached to the upper part of the dark box 42.
[0015]
The shutter blade 44 is provided in front of the dark box 42 and rotates around an opening provided at one end. The shutter blade 44 is held at a position that covers the optical axis by the bias of the spring 51. When the shutter button 17 is depressed, the shutter mechanism is activated, and the shutter lever 50 kicks off one end 44a of the shutter blade 44 to open the shutter opening 47. Thereafter, the shutter blades 44 are returned to their original positions by the bias of the spring 51, and the unexposed photographic film 27 is exposed.
[0016]
The diaphragm plate 45 is disposed between the dark box 42 and the shutter blades 44 and is rotatable about the opening 45a. A small aperture 52 and a large aperture 53 are formed in the aperture plate 45. As shown in FIG. 4A, the large aperture 53 is inserted on the optical axis by the bias of a spring 54. Held in position 1. Reference numeral 55 denotes a stopper provided in the dark box 42 so that the diaphragm plate 18 stops at the first position.
[0017]
The electromagnet 46 is attached to the dark box 42 and is connected to the photometric circuit 56. The photometric circuit 56 is formed on the printed circuit board 36 (see FIG. 2) together with the light receiving element 16, and operates by the current flowing from the battery 38 when the photometric switch 57 is turned on. The light receiving element 16 measures the subject light amount, and the photometry circuit 56 energizes the electromagnet 46 when detecting that the subject light amount is equal to or greater than a reference value. An iron piece 58 is attached to one end of the diaphragm plate 45. When the electromagnet 46 is energized, an attractive force is generated between the electromagnet 46 and the iron piece 58, and the diaphragm plate 45 is moved. After that, as shown in FIG. 4B, the diaphragm plate 45 moves to the second position where the small diaphragm opening 52 is inserted on the optical axis, and the electromagnet 46 and the iron piece 58 come into contact with each other, so that the diaphragm plate 45 is moved. Stops at this second position.
[0018]
FIG. 5 shows the structure of the shutter mechanism. The shutter mechanism includes a shutter lever 50, a delay lever 60, a release lever 61, a governor mechanism 62, a cam 63, and a sprocket 64. The cam 63 is attached to the upper part of the dark box 42 so as to be rotatable about the shaft 63a. The cam 63 is formed with a disc in which a notch opening 63b for locking the release lever 61 is formed, and a semi-disc-shaped convex portion provided in the lower portion thereof. The convex portion has a two-stage configuration of an upper first convex portion 63c and a lower second convex portion 63d. The first convex portion 63c contacts the shutter lever 50, and the second convex portion 63d is a delay. It contacts the lever 60. The shaft 63 a of the cam 63 is attached to a sprocket 64 disposed below the opening 65. Further, since the perforation 27a (see FIG. 2) formed on the photographic film 27 is meshed with the sprocket 64, when the photographic film 27 is fed by winding up the winding knob 22, the sprocket 64 and the cam 63 are shown in the drawing. Rotates counterclockwise.
[0019]
The shutter lever 50 is provided so as to be rotatable by a shaft 65 provided in the dark box 42. One end of a torsion spring 66 provided on the upper part of the shutter lever 50 is in contact with the shutter lever, and the other end is in contact with the dark box 42. The shutter lever 50 includes a shutter protrusion 50 a for kicking the tip 44 a of the shutter blade 44, a hook 50 b that makes contact with the cam 63, and a protrusion 50 c that makes contact with the delay lever 60. When the cam 63 rotates in the counterclockwise direction in the drawing, the first convex portion 63c and the hook 50b of the shutter lever 50 come into contact with each other, and the shutter lever 50 rotates in the clockwise direction in the drawing against the urging force of the torsion spring 66. Thus, shutter charging is performed.
[0020]
The delay lever 60 is provided above the dark box 42 so as to be rotatable, and constitutes a delay mechanism together with the governor mechanism 62. A torsion spring 68 and a rivet 70 are attached to the upper portion of the delay lever 60. A gear 60a is formed at one end of the delay lever 60, and the gear 60a meshes with an escape wheel (described later 73). On the upper portion of the delay lever 60, a protrusion 60b that comes into contact with the convex portion 63c of the cam 63 and an engaging portion 60c that holds the release lever 61 are provided. One end of the torsion spring 68 is in contact with the protrusion 60 b of the delay lever 60, and the other end is in contact with the dark box 42. When the cam 63 rotates counterclockwise in the figure, the second convex portion 63d pushes the projection 60b, so that the delay lever 60 rotates clockwise in the figure against the bias of the torsion spring 68.
[0021]
The release lever 61 includes a release portion 61a, a locking claw 61b, a winding stop portion 61c, and a protrusion 61d, and is rotatable by a shaft 71 provided in the dark box 42. One end of the torsion spring 72 attached to the lower part of the release lever 61 is in contact with the release portion 61a, and the other end is in contact with the dark box. The protrusion 61 d of the release lever 61 is disposed so as to contact the locking portion 60 c of the delay lever 60. The locking claw 61 b is provided to enter the notch opening 63 b of the cam 63 and hold the release lever 61. The winding stop 61c engages with a groove formed around the winding knob 22 when the release lever 61 rotates in the clockwise direction in the drawing, and locks the rotation of the winding knob 22. The release portion 61a is provided so as to contact the shutter button 17, and when the shutter button 17 is depressed, the shutter lever 61 rotates counterclockwise in the figure against the bias of the spring 72, and is locked. The engagement between the claw 61b and the notch opening 63b is released.
[0022]
The governor mechanism 62 is composed of a ganki wheel 73 and an ankle 74, and is disposed on the dark box 42, respectively. The rotational speed of the escape wheel 73 is adjusted by an ankle 74. As described above, the escape wheel 73 is engaged with the gear 60 a of the delay lever 60 and rotates together with the delay lever 60. Therefore, the governor mechanism 62 operates as a speed adjusting mechanism that adjusts the rotational speed of the delay lever 60. The gunki wheel 73 is provided with a fan-shaped rib 75. The rib 75 contacts the photometric switch 57 only while the escape wheel 73 is rotating.
[0023]
FIG. 6 shows a schematic diagram of the shutter mechanism. This figure shows a state before the shutter charge is performed. The delay lever 60 is held by a torsion spring 68 so that the right tooth of the gear 60 a meshes with the gear of the escape wheel 73. In this state, since the photometric switch 57 is separated from the rib 75, photometry is not performed. Further, the torsion spring 72 is charged in the direction in which the release lever 61 is rotated in the clockwise direction in the drawing. Here, since the torsion spring 72 having a smaller bias than the torsion spring 68 of the delay lever 60 is used, the release lever 61 is in a state in which the protrusion 61d is in contact with the locking portion 60c of the delay lever 60. Is retained.
[0024]
When the winding knob 22 is rotated, the photographic film 27 is fed, and the cam 63 is rotated counterclockwise along with the sprocket 64 in the drawing. Then, the first convex portion 63c of the cam 63 contacts the hook 50b of the shutter lever 50, and as shown in FIG. 7, the shutter lever 50 rotates in the clockwise direction in the drawing and is charged.
[0025]
When the cam 63 is further rotated, the second protrusion 63d comes into contact with the protrusion 60b of the delay lever 60, and the delay lever 60 rotates in the clockwise direction in the drawing together with the shutter lever 50. Then, when the delay lever 60 rotates by a certain amount, as shown in FIG. 8, the engagement between the locking portion 60c of the delay lever 60 and the projection 61d of the release lever 61 is released, and the release lever 61 is rotated clockwise in the figure. The locking claw 61 b comes into contact with the cam 63 by rotating. Further, the hook 50b of the shutter lever 50 is separated from the first convex portion 63c of the cam 63, and the shutter lever 50 tends to rotate counterclockwise in the drawing. However, since the projection 50c of the shutter lever 50 is in contact with one end of the delay lever 60, the shutter lever 50 is held with the torsion spring 66 charged.
[0026]
When the winding knob 22 is further rotated, the cam 63 rotates counterclockwise. When the one-frame winding of the photographic film 27 is completed, as shown in FIG. 9, the engaging claw 61b of the release lever 61 enters the notch opening 63b and the release lever 61 is held. At this time, the release lever 61 rotates in the clockwise direction in the drawing, and the winding stopper 61c meshes with the teeth provided around the winding knob 22, so that the rotation of the winding knob 22 is locked. Since the protrusion 61d of the release lever 61 is inserted on the rotation track of the locking portion 60c, the delay lever 60 is held in a state where the locking portion 60c is in contact with the protrusion 61d of the release lever 61. The shutter charge is performed by the above operation.
[0027]
When the shutter button 17 is pushed down while the shutter is charged, the release portion 61a of the release lever 61 contacts the shutter button 17, and the release lever 61 rotates counterclockwise in the figure against the bias of the spring 72. . Then, as shown in FIG. 10, the protrusion 61d of the release lever 61 is retracted from the rotation track of the locking portion 60c of the delay lever 60, so that the delay lever 60 rotates counterclockwise in the figure. With the rotation of the delay lever 60, the escape wheel 73 rotates in the clockwise direction in the figure. Then, the rib 75 attached to the escape wheel 73 comes into contact with the photometric switch 57, the photometric switch 57 is turned on, the photometric circuit 56 is activated, and the aperture is switched.
[0028]
At this time, since the protrusion 50c of the shutter lever 50 remains in contact with one end of the delay lever 60, the shutter lever 50 is held in a charged state. Further, the delay lever 60 rotates while receiving a frictional force due to the urging force of the torsion spring 66 attached to the shutter lever 50. In order to secure a sufficient rotational force against the frictional force, the torsion spring 68 on the delay lever 60 side has a larger bias than the torsion spring 66 on the shutter lever 50 side.
[0029]
The delay lever 60 continues to rotate while holding the shutter lever 50. When the delay lever 60 rotates by a certain amount, the end of the delay lever 60 deviates from the rotation trajectory of the protrusion 50c of the shutter lever 50, and the shutter lever 50 starts to rotate counterclockwise in the drawing. Then, the shutter protrusion 50a kicks off the tip end portion 44a of the shutter blade 44, and the photographic film 27 is exposed. After that, the delay lever 60 continues to rotate, and when the rib 75 moves away from the photometry switch 57, the delay lever 60 stops and the shutter operation ends.
[0030]
FIG. 12 shows a timing chart of the shutter mechanism. Since the movement of the diaphragm plate 45 is taken into consideration, it is assumed that the subject light quantity is bright. When the shutter button 17 is pressed down at time T1, only the release lever 61 moves, and the delay lever 60 is released and stopped at time T2. Thereafter, the delay lever 60 starts rotating, and at time T3, the photometric switch 57 is turned on, and the photometric circuit 56 is activated. Then, after the aperture is switched, the shutter lever 50 is unlocked at time T4, the shutter lever 50 starts rotating, and at time T4, the shutter blades 44 rotate to perform exposure. After the exposure is completed at time T6, the photometry switch 57 is turned off at time T7, the rotation of the delay lever 60 is stopped at time T8, and the shutter operation is completed.
[0031]
Here, since the rotation speed of the delay lever 60 can be changed by the governor mechanism 62, the interval between the time T3 when the photometry is started and the time T4 when the shutter lever 50 starts rotating can be arbitrarily adjusted. . This time interval (T4-T3) is preferably set to 10 ms to 60 ms. At this time, since the shutter blades 44 are opened after switching the aperture, exposure control can be performed reliably.
[0032]
Further, in the shutter device configured as described above, the only member that receives the braking by the governor mechanism 62 is the delay lever 60, and the rotation of the shutter lever 50 itself is not braked, so that the shutter speed is not affected.
[0033]
The operation of the present embodiment will be described. The photographer rotates the winding knob 22 to set the unexposed photographic film 27 inside the exposure frame 32. As the winding knob 22 rotates, the shutter lever 50 and the delay lever 60 are charged. When the photographic film 27 is wound up by exactly one frame, the release lever 61 rotates and the winding stop 61c comes into contact with the winding knob 22 to lock the winding knob 22. In a state where the shutter lever 50 is charged, the photometric switch 57 is not turned on unless the shutter button 17 is pressed down, so that useless consumption of the battery 38 is suppressed.
[0034]
Thereafter, the subject is framed and the shutter button 17 is pressed down. Then, the delay lever 60 is unlocked, and the delay lever 60 starts to rotate. Thereafter, the photometric switch 57 is turned on and the photometric circuit 56 is activated. When the subject light quantity is equal to or greater than the predetermined value, a current flows from the photometry circuit 56 to the electromagnet 46, and the diaphragm plate 45 moves to the second position. On the other hand, when the subject light quantity is less than or equal to the predetermined value, the electromagnet 46 is not energized, and the diaphragm plate 45 is held in the first position by the bias of the spring 54. At this time, since the shutter lever 50 is locked by the delay lever 60, exposure is not performed while the diaphragm plate 45 is moving.
[0035]
When the delay lever 60 rotates for a certain time, the shutter lever 50 is unlocked, the shutter lever 50 starts to move, kicks the shutter blade 44, and the photographic film 27 is exposed. Thereafter, the photometric switch 57 is turned off, the delay lever 60 is stopped, and the photographing is finished.
[0036]
When the subject is not sufficiently bright as in indoor shooting, the exposure is made through the large aperture 24. In this case, since the exposure amount is increased, it is possible to obtain a printed photograph with appropriate exposure without causing underexposure. On the other hand, when the subject is very bright, such as when shooting outdoors on a sunny day, the exposure is made through the small aperture 23. Since the exposure amount is reduced to an appropriate value by the small aperture 23, it is possible to perform photographing without causing overexposure.
[0037]
In a very dark situation such as at night, the photographer turns on the strobe switch 15 to perform strobe photography. Then, the strobe circuit is activated and the capacitor 37 is charged. After the completion of charging is detected by the flashing of the charging completion confirmation window 21, the shutter button 17 is pressed down to take a picture. In this case, the subject light quantity is equal to or less than a predetermined value, and no current flows through the electromagnet 46. Therefore, exposure is performed through the large aperture opening 24.
[0038]
【The invention's effect】
As described above, according to the present invention, the restraint is released by pressing the shutter button, the shutter lever is rotated while being held at the charging position, and the holding of the shutter lever is released by rotating to a certain position. A delay lever that allows movement to the release position, a metering switch that is activated by the delay lever before the delay lever rotates to a certain position, and a metering switch that operates the metering means, adjusts the rotation speed of the delay lever, and the metering switch turns on And a speed control mechanism that prevents the delay lever from rotating to a certain position until the switching of the diaphragm is completed by the diaphragm switching means, while preventing battery consumption due to useless photometry, Aperture can be switched reliably.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external appearance of a lens-fitted photo film unit.
FIG. 2 is a perspective view showing the inside of a lens-fitted photo film unit.
FIG. 3 is a perspective view showing an internal structure of an exposure control mechanism.
FIGS. 4A and 4B are schematic views showing a main part of the exposure control apparatus, in which FIG. 4A shows a case where the subject is bright and FIG. 4B shows a case where the subject is dark.
FIG. 5 is a perspective view showing a structure of a shutter mechanism.
FIG. 6 is a schematic view showing a main part of a shutter mechanism.
FIG. 7 is a schematic view showing a main part of the shutter mechanism in a state where only the shutter lever is charged.
FIG. 8 is a schematic view showing a main part of the shutter mechanism in a state where the delay lever is charged.
FIG. 9 is a schematic diagram showing a main part of the shutter mechanism when the shutter charge is completed.
FIG. 10 is a schematic diagram illustrating a main part of the shutter mechanism immediately after the shutter button is pressed down.
FIG. 11 is a schematic view showing a main part of a shutter mechanism during exposure.
FIG. 12 is a timing chart of the shutter mechanism.
[Explanation of symbols]
10 unit body 22 winding knob 44 shutter blade 50 shutter lever 57 metering switch 60 delay lever 61 release lever 62 governor mechanism 63 cam 64 sprocket 66, 68, 72 torsion spring

Claims (4)

Used together with aperture switching means for switching the aperture in accordance with a photometric signal from a photometric means for measuring subject brightness, and when the shutter button is pressed, the shutter lever is moved from the charge position toward the release position by spring bias. In the shutter device used for the lens-fitted photo film unit, which is operated in a kick-off system in which the shutter blades are kicked to open and close during the movement, and the photographic film is loaded in advance .
A delay lever that is released by pressing a shutter button, rotates while holding the shutter lever in a charging position, and releases the holding of the shutter lever by rotating to a certain position and allows movement to a release position;
A photometric switch for operating the photometric means;
In conjunction with the rotation of the delay lever, a switch pressing member that turns on the photometry switch before the delay lever rotates to the predetermined position;
Adjusting the rotational speed of the delay lever, the switch pressing member until the completion of the switching of the stop by the stop changing means after turning on the photometric switch, speed control mechanism which prevents the rotation delay lever to a predetermined position A shutter device for a lens-fitted photo film unit . The governor mechanism is a governor mechanism comprising an escape wheel that meshes with a gear formed on a delay lever, and an ankle that engages with the escape wheel and adjusts the rotational speed of the escape wheel. 2. A shutter device for a film unit with a lens according to 1. 3. The shutter device for a film unit with a lens according to claim 2, wherein the switch pressing member is integrally attached to the escape wheel. The shutter of the film unit with a lens according to any one of claims 1 to 3 , wherein a time from when the photometric switch is turned on until the delay lever reaches the predetermined position is set to 10 ms to 60 ms. apparatus.

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