JPH09329827A - Focal plane shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the consumption of a battery as little as possible in the case of controlling the traveling of blades by a motor, as to a focal plane shutter constituted of a 1st blade and a 2nd blade. SOLUTION: The traveling of the 1st blade 14 driven by a 1st blade driving arm 16 is locked at the initial position by a 1st blade retaining lever 18, the 1st blade retaining lever 18 is released from locking by the cam 25b of the output shaft of a 1st blade operating motor 25 which is energized for a short time and operated by a 1st blade operating motor driver at releasing, and then, the 1st blade 14 travels in accordance with the rotation of the 1st blade driving arm 16, then, the exposure operation is started. Besides, as for a 2nd blade operating motor 26 which is energized for a short time and operated by a 2nd blade operating motor driver just before the completion of the exposure, the 2nd blade retaining lever 19 is released from locking by the cam 26b of the output shaft of the motor 26, then, the 2nd blade 15 travels in accordance with the rotation of the 2nd blade driving arm 17, then, the exposure is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control mechanism for causing a shutter curtain of a focal plane shutter to travel by a predetermined control signal.

[0002]

2. Description of the Related Art Conventionally, as a shutter blade traveling control mechanism for a focal plane shutter, a release type control system in which a spring-biased shutter blade drive arm is attracted and released by a magnet has been widely used. That is, when the release switch 1 is pressed as shown in the block diagram of the blade drive system of FIG. 4 and the time chart of the drive system of FIG. 5, the release signal is input to the CPU 2 for calculation, and then the leading blade magnet driver is operated. 3 and the trailing blade magnet driver 4 are turned on, and leading blade magnet driving current and trailing blade magnet driving current flow through the leading blade magnet 5 and trailing blade magnet 6, respectively. Then, a delay time t for timing with another mechanism
After ₀ seconds, the leading blade magnet separation timing signal is C
The leading blade magnet drive current output from PU2 is turned off. Next, when the exposure end time is reached after the lapse of time t ₁ second, the CPU 2 outputs the trailing blade magnet separation timing signal, and the trailing blade magnet drive current is turned off. Further, when the exposure time becomes long, the time from the output of the leading blade magnet separation timing signal to the output of the trailing blade magnet separation timing signal becomes t ₁₁ seconds as shown in FIG. As described above, the magnet drive current for the trailing blade continues to flow for t ₀ + t ₁ seconds or t ₀ + t ₁₁ seconds without being turned off until the exposure is completed, and therefore the battery is consumed depending on the length of the exposure time.

[0003]

However, in the case of the release type control system, it is necessary to continuously attract the magnet so as to lock the trailing blade drive arm during the exposure until the trailing curtain is moved, and therefore, the long-time control is required. Not only is the battery depleted during time exposure, but it is also possible that the battery will run out during open shooting and the shutter will not operate normally.

An object of the present invention is to provide a focal plane shutter which eliminates the above-mentioned drawbacks of the prior art and does not consume a battery even when an exposure is performed for a long period of time and enables open photographing.

[0005]

In order to achieve the above-mentioned object, the present invention drives a releasing member for releasing a tightening member for stopping the traveling of a second blade member which is a rear blade of a focal plane shutter. Is set just before the exposure is completed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention as set forth in claim 1 includes a first blade member that shields the optical path in the initial state in advance, and a first tightening member that locks the traveling of the first blade member. , A first release member for releasing the first tightening member, a first drive circuit for driving the first release member, and an optical path opened by traveling of the first blade member Second blade member, a second tightening member that locks the traveling of the second blade member, a second release member that releases the second tightening member, and a second release A second drive circuit for driving the member,
The second drive circuit prevents the second release member from being driven until just before releasing the second tension member, so that the first blade member travels to start exposure and then Since the second release member is not driven until the second blade member travels, it is possible to prevent the battery from being consumed even if the exposure is performed for a long time.

According to the second aspect of the present invention, since the second release member is composed of a motor having a cam on its shaft, the second blade member can be operated by driving the motor for a short time. It is possible to reduce the battery consumption. Claim 3
In the present invention shown in FIG. 3, since the first release member is composed of a motor having a cam on its shaft, the first blade member can be operated by driving the motor for a short time, so that the battery is consumed. Less is. According to the present invention as set forth in claim 4, the driving time of the motor on the shaft of the first or second releasing member is a short pulse-like time, about 5 to 10 msec, so that the consumption of the battery by the motor driving is reduced. Especially good for.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view of a focal plane shutter of this embodiment, and FIG. 2 is a block diagram of a shutter drive system. In FIG. 1, 11 is a shutter base, 12 is an aperture provided in the shutter base 11, and 13 is a cover member fixed to the back surface side of the shutter base 11 at intervals. Reference numerals 14 and 15 denote leading and trailing blades composed of a plurality of blade members which are light-shielding members, and are axially supported on the back side of the shutter base 11 by shafts 14a and 15a which are erected upright through the shutter base 11. ing. Reference numerals 16 and 17 denote a leading blade driving arm and a trailing blade driving arm, which are rotatably supported by the shafts 14a and 15a on the front side of the shutter base 11 and project from one end of the shafts 16a and 1a.
7a are arc grooves 1 formed on the shutter base 11, respectively.
The front blade 14 and the rear blade 15 are engaged with each other through 1a and 11b to be rotatable. And the leading blade 14
The trailing blade 15 and the trailing blade 15 are guided by the cover member 13 at their traveling positions by the rotation of the leading blade driving arm 16 and the trailing blade driving arm 17, respectively, and rotate to form a predetermined slit in the aperture 12. In addition, the leading blade drive arm 16
Is an upper base 23 wound around the shaft 16a and one end of which will be described later.
The trailing blade drive arm 17 is urged in the direction of arrow A (clockwise) by a torsion spring 16b fixed to the shaft 17a, and the trailing blade drive arm 17 is wound around the shaft 17a and has one end fixed to the upper base 23. It is biased in the direction of arrow B (clockwise) in the figure.

Reference numerals 18 and 19 are a leading blade tensioning lever and a trailing blade tensioning lever, which are rotatably supported by shafts 18a and 19a provided upright on the shutter base 11 and one end of which is the shutter base 11. Torsion spring 18 fixed to
b and 19b, arrow D, E direction in the figure (counterclockwise direction)
The leading blade drive arm 16 and the trailing blade drive arm 17 are locked at the set position. Two
Reference numerals 0, 21, 22 are link plates, and the link plates 20 and 22 are respectively shafts 20a provided upright on the shutter base 11.
And 22a are rotatably supported by the link plate 21, and the link plate 21 has both ends at the shafts 21a and 21b, respectively.
And 22 to form a link mechanism,
Has cam surfaces 22b and 22c. Then, when the link plate 20 is pushed from the outside in the direction of arrow C (leftward direction) in the drawing to swing, the cam surfaces 22b and 22c of the link plate 22 push and rotate the leading blade driving arm 16 and the trailing blade driving arm 17, respectively. , The leading blade drive arm 16 is swung in the direction opposite to the arrow A direction in the drawing, and the trailing blade drive arm 17 is swung in the direction opposite to the arrow B direction in the drawing, so that the leading blade tightening lever 18 and the trailing blade tightening lever 18 respectively. It is adapted to be locked at the set position by the constant lever 19.

Reference numeral 23 denotes an upper base, which is the shutter base 11
Of a pair of columns 24a, 24b and the shaft 14a which are erected on the
And 15a. Reference numeral 25 is a leading blade actuating motor, and 26 is a trailing blade actuating motor.
The output shafts 25a and 26a are mounted on the upper side thereof, and stoppers (not shown) are attached to the respective output shafts 25a and 26a so that the shafts are restricted from rotating more than a certain angle. In addition, the output shafts 25 of the leading blade operating motor 25 and the trailing blade operating motor 26, respectively.
Cams 25b and 26b are fixed to a and 26a, and torsion springs 27 and 28 whose one ends are fixed to the upper base 23 are hooked on the cams 25b and 26b, respectively. The stoppers are urged in directions opposite to the clockwise direction and the G direction (clockwise direction), respectively, and are in contact with one end side of the stopper. Then, the leading blade operating motor 25
When a driving current flows in the direction of arrow F in the figure, the cam 25b flicks off the leading blade tensioning lever 18, and then the leading blade actuating motor 25 slightly rotates by inertia, not shown. Abut the stopper and stop. Similarly, when a drive current flows through the trailing blade operating motor 26, the trailing blade operating motor 26 slightly rotates after the cam 26b flips the trailing blade tensioning lever 19 by rotating in the direction of arrow G in the figure. It rotates by inertia and contacts a stopper (not shown) to stop. When the drive current to the motor is cut off, the cams 25b and 26b are returned to their initial positions by the biasing forces of the torsion springs 27 and 28.

In FIG. 2, reference numeral 31 is a release switch,
Reference numeral 32 denotes a CPU as an arithmetic circuit that calculates an appropriate exposure time from the photographing conditions and generates a traveling signal of each blade so as to form a slit matching the result, and a signal from the release switch 31 is input. A leading blade actuation motor driver 33 turns on / off a current for operating the leading blade actuation motor 25 in response to a signal from the CPU 32.
34 is a trailing blade operating motor driver which turns on / off a current for operating the trailing blade operating motor 26 in response to a signal from the CPU 32.

In this embodiment having the above-described structure, first, when the release switch 31 is pressed, the release signal is CP.
After being input to U32 and calculated, the leading blade motor driving timing signal and the trailing blade motor driving timing signal are output to the leading blade operating motor driver 33 and the trailing blade operating motor driver 34, respectively. Then, the leading blade operating motor driver 33 and the trailing blade operating motor driver 3
4 drives the trailing blade operating motor 25 and the trailing blade operating motor 26 according to the motor drive timing signal.

Next, the exposure operation of the shutter will be described with reference to FIG.
This will be described with reference to the time chart of FIG. In the initial state, the leading blade driving arm 16 and the trailing blade driving arm 17 are held in a state where they are locked at the set position, respectively, and are waiting for a release signal to be input. Therefore, when the release signal is applied, the leading blade motor drive current is t ₂ after a delay time for timing with other mechanisms, that is, t ₀ seconds in FIG.
The first blade actuating motor 25 flows for a second, rotates in the direction of arrow F in the figure, and when the cam 25b flies off the leading blade tensioning lever 18, the leading blade drive arm 16 is unlocked and rotated, and the leading blade 14 moves. Runs and starts exposure.

Then, according to the calculation result of the CPU 32, an appropriate time for obtaining a predetermined exposure amount, t ₁ shown in FIG.
When a drive current flows to the trailing blade actuating motor 26 for a period of t ₂ seconds after a second, the trailing blade actuating motor 26 rotates in the direction of the arrow G in the figure to flip the trailing blade tensioning lever 19 to fly off the trailing blade actuating arm 17. The lock is released, and the rear blade 15 runs to complete the exposure operation. When the exposure time becomes long, the time from the output of the leading blade motor drive timing signal to the output of the trailing blade motor drive timing signal becomes long as t ₁₁ seconds shown in FIG. When the exposure operation is completely completed, the link 20 swings in the direction of the arrow C in the figure by receiving power from the outside, and the leading blade driving arm 16 and the trailing blade driving arm 17 are respectively attached to the cam surfaces 22b and 22c of the link 22. In the figure, they are pushed and oscillated in the direction opposite to the arrow A and the direction opposite to the arrow B, locked by the leading blade tension lever 18 and the trailing blade tension lever 19 at the set position, and the release signal is input again. It remains as it is until it is opened.

Then, as described above, the leading blade tensioning lever 1
8 and the rear blade tensioning lever 19 when the tension is released, as shown in FIG.
As t ₂ seconds in the above, it suffices to supply a current to the leading blade operating motor 25 and the trailing blade operating motor 26 only for a short time of about 5 to 10 msec. Therefore, after driving the leading blade operating motor 25, any long interval can be set. When the rear blade actuating motor 26 is driven after being placed, the battery is not consumed during that time.

In this embodiment, the shutter member is a vertically running focal plane shutter using a plurality of blade members, but a lateral running focal plane shutter using a cloth curtain as the shutter member is also available. It goes without saying that it is good.

[0017]

Correspondence between Embodiments and Embodiments In the above embodiments, the leading blade 11 and the trailing blade 12 are respectively the first and second blade members, and the leading blade tensioning lever 18 and the trailing blade tensioning lever 19 are respectively the first and second blade members. A first blade actuation motor 25 having a cam 25b on an output shaft 25a and an output shaft 2 on the first and second tension members.
The trailing blade actuating motor 26 having the cam 26b at 6a serves as the first and second releasing members, and the leading blade driving motor driver 33 and the trailing blade driving motor driver 34 controlled by the CPU 32 carry out first and second driving, respectively. Each corresponds to a circuit. The above is the correspondence relationship between each configuration of the embodiment and each configuration of the present invention, but the present invention is not limited to this embodiment, and the function shown in the claims or the function of the configuration of the embodiment It goes without saying that any structure can be used as long as it can be achieved.

[0018]

As described above, according to the present invention as set forth in claim 1, in the initial state, the first blade member that shields the optical path in advance and the first tension member that locks the traveling of the first blade member are provided. The fixed member, the first release member for releasing the first tightening member, the first drive circuit for driving the first release member, and the first blade member are opened by traveling. A second blade member that shields the optical path; a second tension member that locks the travel of the second blade member; a second release member that releases the second tension member; A second drive circuit for driving the second release member, wherein the second drive circuit does not drive the second release member until immediately before releasing the second tightening member. It is possible to reduce the consumption of the battery that operates the member for exposure. Further, in the present invention as set forth in claim 2, the second releasing member is constituted by a motor having a cam on its shaft, and in the present invention as set forth in claim 3, the first releasing member is Since the motor is provided with a cam on the shaft, the motor drive time is shortened, which is effective for battery consumption. According to the present invention as set forth in claim 4, the driving time of the motor on the shaft of the first or second releasing member is a short pulse time, about 5 to 10 msec.
Therefore, the consumption of the battery can be minimized.

[Brief description of drawings]

FIG. 1 is a perspective view of a focal plane shutter of one embodiment according to the present invention.

FIG. 2 is a block diagram of an electric circuit for driving the shutter.

FIG. 3 is a time chart of the drive system.

FIG. 4 is a block diagram of an electric circuit for driving a conventional focal plane shutter.

FIG. 5 is a time chart of the drive system.

[Explanation of symbols]

11 ... Shutter base, 12 ... Aperture, 13 ...
Cover member, 14 ... Front blade, 15 ... Rear blade, 16 ...
.Leading blade drive arm, 17 ... Rear blade drive arm, 18
..Front blade tensioning levers, 19 ... Rear blade tensioning levers, 2
0, 21, 22 ... Link plate, 23 ... Upper base, 24
a, 24b ... props, 25 ... leading blade actuating motor, 25
b..cam, 26..rear blade actuating motor, 26b..cam, 27,28..torsion spring, 31..release switch, 32..CPU, 33..first blade actuating motor driver, 34..rear Blade operation motor driver.

Claims (4)

[Claims] 1. A first blade member that shields an optical path in an initial state in advance, a first tightening member that locks the traveling of the first blade member, and the first tightening member is released. A first release member, a first drive circuit that drives the first release member, a second blade member that blocks the optical path that the first blade member travels and is open, and the second A second tightening member that locks the traveling of the blade member, a second release member that releases the second tightening member, and a second drive circuit that drives the second release member. The focal plane shutter, wherein the second drive circuit does not drive the second release member until just before releasing the second tightening member. 2. The focal plane shutter according to claim 1, wherein the second releasing member is a motor having a cam on its shaft. 3. The focal plane shutter according to claim 1, wherein the first releasing member is a motor having a cam on its shaft. 4. The driving time of the motor on the shaft of the first or second releasing member is a short pulse time, about 5 to 10 ms.
The focal plane shutter according to claim 2, wherein the focal plane shutter is ec.