JPH0516012B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electric focal plane shutter device.

(Prior Art and Problems to be Solved) A conventional focal plane shutter is constructed so that the energy for running the leading curtain and the trailing curtain is stored in a spring means in conjunction with a film winding mechanism. . That is, both curtains are stretched between a winding drum rotated in conjunction with a film winding mechanism and a spring drum biased in one direction by a spring means such as a coil spring. It is hoisted from the drum side to the winding drum side. During this winding process, the energy stored in the spring means of the spring drum causes both curtains to travel one after another when the shutter is operated, and are wound onto the spring drum. A plane (focal plane) is exposed to light at a desired shutter speed.

Therefore, in such conventional focal plane shutters, the spring means of the spring drum is an important member for properly running the first and second curtains, and its precision is required, and the curtain speed is also kept as low as possible. It is hoped that it will be fast. That is, if the curtain speed is always constant, proper exposure can be performed, and the faster the curtain speed is, the more problems such as camera shake and problems when photographing a moving object can be eliminated. However, with the configuration using the above-mentioned spring means, there is a limit to its realization, and some kind of countermeasure is desired.

Furthermore, the above-mentioned conventional structure requires a transmission member such as a gear to charge the spring means during film winding, which not only requires a large number of parts and a complicated structure, but also causes a moment of inertia of these components to There were also problems with poor acceleration and poor shutter accuracy.

Furthermore, it is well known that as the functions of today's products are diversifying, there is a growing trend toward electric automation. Such a demand is also great in the field of cameras, and there is a trend towards automation using motors, for example, automatic winding and rewinding.

By the way, the problem in achieving the above-mentioned automation is how to distribute and utilize the current supplied from the battery used as the power source in a well-balanced manner to create a configuration that allows multiple functions to operate properly.

In other words, in a conventional camera mechanism, when winding the film, the winding mechanism moves the film by a certain amount, and in conjunction with this, energy is charged to the shutter mechanism and mirror drive mechanism, and the film is moved to confirm the film advance. Since time-sequential operations such as counter counting are performed in one operation, automating this would require an excessive amount of motor torque and an extremely large amount of current, resulting in problems with the number and quality of batteries. Therefore, it is desired that some kind of countermeasure be taken from this point of view as well.

In response to these demands, the present invention proposes a direct drive type shutter using a mechanically independent motor, instead of the conventional film winding-related operation in which the shutter curtain is moved using the stored force of a spring. In addition to reducing the torque during film winding to avoid excessive current flowing at one time, the direct-acting type uses a motor that does not use springs, so the leading and trailing curtains can be run properly and reliably, and they can also be controlled. It is an object of the present invention to provide an electric focal plane shutter device that can be easily operated and that can improve shutter accuracy.

On the other hand, in a focal plane shutter, an electric motor is used as a driving means for moving the shutter curtains, and each curtain is returned to its starting position by the reversal of the motor and the stored force of a spring. In addition, a structure in which a solenoid clutch means and a brake means for restraining the rotation of the corresponding drive system in conjunction with the clutch means between the motor and the drive system of each curtain is disclosed in Japanese Patent Application Laid-Open No. 55-1999.
It is disclosed in Publication No. 106436.

However, this configuration requires operations such as rotating the motor, connecting the clutch means using a solenoid, and then disengaging the brake means in conjunction with this to transmit rotational force and run the shutter curtain. However, it is troublesome and complicated both in terms of structure and operation.

(Means for Solving the Problems) In view of the above-mentioned circumstances, the present invention provides a curtain catch that locks the leading and trailing curtains of a focal plane shutter that has the habit of returning to the starting position against this returning habit. a shutter curtain position detection sensor that detects the initial position and end position of the leading and trailing curtains; The apparatus includes an electric control means that energizes the leading and trailing curtain coreless motors at the initial position in response to a start signal, and stops the energization when the shutter curtain position detection sensor detects the end of running of the curtain, and detects the end of running of the trailing curtain. The front curtain, which has already been locked at the travel end position, is released from the lock, and the front and rear curtains are automatically returned to the initial position.

(Example) Hereinafter, the present invention will be explained in detail using an example shown in the drawings.

FIG. 1 shows an embodiment of the device that is the premise of the electric focal plane shutter device according to the present invention. The figure shows the state before the shutter starts, which is the opposite state from the conventional device. It is in.

In the figure, reference numerals 1 and 2 refer to motors arranged in parallel, and motors for running the rear curtain; numerals 3 and 4 refer to motors 1 and 2, which are arranged in parallel and opposite to these motors 1 and 2, and the rear curtain start position. These four drums 1, 2, 3, and 4 are provided with return springs, and are erected immediately in front of a film surface (focal surface) 5, facing each other on the left and right sides thereof. The front curtain 6 and the rear curtain 7 are stretched between motors 1 and 2 and spring drums 3 and 4, respectively.

To explain this in detail, the left end 6a of the front curtain 6 is connected to the rotor (armature) 10 in the front curtain travel motor 1.
It is glued to the outer periphery of the rotor and is configured to be directly wound around the rotor when driven. A ribbon 12 is connected to the right end of this leading curtain 6 via a connecting fitting 11.
a, 12b are connected, and these ribbons 12a, 1
The other end of 2b is wound around the spring drum 3 for returning to the leading curtain start position. in this case,
This spring drum 3 is biased clockwise in the figure by a spring 14 on a shaft 13.

Further, the right end of the trailing curtain 7 is adhered to and wound around the spring drum 4 for returning to the trailing curtain start position. Of course, like the spring drum 3 described above, this spring drum 4 is also biased clockwise in the figure by a spring 16 on the shaft 15. On the other hand, the left end of the trailing curtain 7 is similarly connected to a connecting fitting 17 at a position substantially overlapping with the connecting fitting 11 of the leading curtain 6, and ribbons 18a and 18b are connected to this connecting fitting 17. The other ends of these ribbons 18a and 18b are fixed to cylindrical parts 19a and 19b that are integrated with a rotor (not shown) in the trailing curtain traveling motor 2, and are configured to be wound up by the rotation of the motor. ing.

Here, the above-mentioned leading and trailing curtain traveling motors 1 and 2 are used.
To explain the specific structure of the cup type coreless motor shown in Fig. 2, reference numeral 20 in the figure
is a rotating shaft, 21 is an external cylindrical body disposed around the rotating shaft, and a cylindrical permanent magnet 2 is installed inside this external cylindrical body 21.
A mounting body 23 to which 2 is fixed is inserted and fixed, and the rotating shaft 20 is configured to be freely rotatable with respect to this mounting body 23. In this case, the external cylindrical body 21 and the mounting body 23 are made of magnetic material, and the permanent magnet 22
It becomes the yoke of

A moving coil 24 is installed as a rotor in the gap between the permanent magnet 22 and the external cylindrical body 21, and this coil 24 is fixed on the rotating shaft 20 together with a commutator 25 via a fixed disk 26. It has a structure that rotates by supplying current from the

The front curtain drive motor 1 according to the present invention has a structure substantially similar to that of the coreless motor described above, and the difference is that, as shown in FIG. 30, and the leading curtain 6 is wound around the rotor 10 (moving coil 24) through this slit 30. That is, the leading curtain 6 is caught in the gap between the external cylindrical body 21 and the rotor 10. Of course, the first act 6
is made of non-magnetic material so as not to affect the magnetic field of the motor.

In addition, in the trailing curtain traveling motor 2, its rotation shaft 31
Cylindrical portions 19a and 19b are fixed to both ends of the ribbon, and these cylindrical portions 19a and 19b are configured to wrap around the ribbons 18a and 18b on the rear curtain 7 side by rotating together with the rotating shaft 31 by a rotor. There is.

If such a configuration is adopted, it becomes possible to run the leading and trailing curtains 6 and 7 while taking advantage of the coreless motor's quick startup speed.
The benefits are great.

In this case, the external cylindrical bodies 21 of the motors 1 and 2 are fixed to a frame of a camera body (not shown), and the respective rotating shafts 20, 31 are rotatably supported by the frame (also not shown). In addition,
In the figure, reference numerals 32 and 33 indicate pulleys for guiding the ribbons 12a, 12b, 18a, and 18b of the front and rear curtains 6 and 7 in the right angle direction, respectively.

Therefore, by adopting the above-mentioned configuration, the motors 1 and 2 can be activated by the shutter start signal.
are sequentially started to rotate, and the leading curtain 6 and trailing curtain 7 travel to the left in the figure just in front of the film surface 5 with a desired slit width, and exposure is performed. and,
The problem at this time is that when both curtains 6 and 7 run, the spring 1 on the spring drum 3 and 4 side
4 and 16 are stored, the running is completed, and motors 1 and 16 are
When 2 stops, there is a force that tries to return.

Therefore, according to this embodiment, the first and second curtains 6, 7
When the motors 1 and 2 have finished running, the rotation shafts 2 of the motors 1 and 2
A locking mechanism is provided to temporarily lock 0 and 31. To explain this using Figure 1, 4 in the figure
0 and 41 are the rotation shafts 20 and 2 of the motors 1 and 2, respectively.
It is a locking disk fixed on the 31, and its outer circumferential portion has first notches 40a, 41a that lock the trailing curtains 6, 7 at the start position, and a second notch 40a, 41a that locks the trailing curtains 6, 7 at the end position. Notches 40b and 41b are formed.

42 is a notch 40 of the locking disc 40 on the front curtain 6 side.
a, 40b having a locking portion 42a that engages with the first
This locking lever is biased counterclockwise in the figure by a spring 43, that is, toward the locking disk 40 side. Further, 44 is a second locking lever having a locking portion 44a that engages with notches 41a and 41b of the locking disk 41 on the rear curtain 7 side, and is similarly moved counterclockwise in the figure by a spring 45, i.e. It is urged toward the locking disc 41 side. A pin 46 protruding from a portion of the second locking lever 44 close to the locking portion 44a is connected to the tip portion 4 of the first locking lever 42.
2b. Also,
At the other end of the second locking lever 44, there is an iron piece that is attracted to a magnet 47 for rotating the second locking lever 44 clockwise, that is, in a direction away from the locking disc 41. 44b is attached.

Further, sensors 48 and 49 for detecting the position of the shutter curtains are provided on both ends of the film surface 5 along which the leading and trailing curtains 6 and 7 run. These sensors 48 and 49 detect the start position and end position of the curtain connecting plates 11 and 17. For example, magnetic sheets are attached to these connecting plates 11 and 17, respectively, and the sensors 48 and 49 are replaced with Hall elements. By configuring this, each switch operates as a proximity switch, making it possible to detect each position. By reading the current state of the leading curtain 6 and trailing curtain 7 in this manner, the central control section can issue instructions for sequential operation.

FIG. 3 shows the control state, and the operation sequence of the present invention including this will be explained as follows.
In the state shown in FIG. 1, both the connecting plates 11 and 17 are sensed by the sensor 48 with both curtains 6 and 7 closed, and it is determined that the shutter is not started.

Now, when a start signal for shooting is sent from the release button (not shown), the start circuit 50
A signal is transmitted to the sequential control circuit 51, and from the position detection signals of the sensors 48 and 49, it is determined that the position is before the shutter start. Then, the start signal instructs the time setting circuit 52 to set the start reference, and at the same time, the motor drive circuit 5 for the front curtain
3, the motor 1 for driving the leading curtain is started to rotate, and the set time is counted.

When the motor 1 rotates, the leading curtain 6 is wound around the rotor 10 which rotates counterclockwise, and the leading curtain 6 travels in the direction of the arrow in FIG. 1 to expose the film surface 5. At this time, the spring 14 in the spring drum 3 is charged. In addition, the rotating shaft 2
The first locking lever 42 that locks the locking disc 40 on the front curtain 6 is pushed away by the counterclockwise rotation when the front curtain is running, and does not lock it. Therefore, it travels just in front of the film surface 5.

When the leading curtain 6 completes its travel, the connecting plate 11 connects to the sensor 4.
When the vehicle reaches position 9, a travel completion signal is sent out, the power to the motor 1 is cut off, and the motor 1 is stopped. At this time, since the rotational torque of the rotor 10 disappears, the front curtain 6 tries to be returned by the stored force of the spring 14, but the notch 40 of the locking disc 40
b is designed to be located at a position corresponding to the locking portion 42a of the top locking lever 42, and the function of this locking lever 42 prevents the rotor 10 from rotating in the opposite direction.

Also, in the second curtain 7, when the set time is counted,
The motor 2 is energized and rotated by the motor drive circuit 54 in response to a signal from the timing circuit 52, and the motor 2 similarly runs in the direction of the arrow in FIG. 1 and closes the shutter. At this time, the ribbons 18a, 18 are attached to the cylindrical parts 19a, 19b integral with the rotor of the motor 2.
It goes without saying that the trailing curtain 7 travels by being wound around b.

Then, like the leading curtain 6, when the connection plate 17 travels from the position of the sensor 48 to the position of the sensor 49, the sensor 49 senses the end of the travel and sends out a travel completion signal, so that the motor 2 is energized. is cut off and rotation is stopped. At this time, the spring 16 of the spring drum 4 that has been stored during running exerts a force to return the trailing curtain 7, but this is also caused by a notch in the locking disc 41 on the rotating shaft 31, similar to the leading curtain 6. The locking portion 44a of the second locking lever 44 is attached to the portion 41b.
is engaged to restrict its rotation and prevent the rear curtain 7 from returning.

In this way, the running of the front curtain 6 and the rear curtain 7 is completed, but for the next shutter operation, it is necessary to return both curtains 6 and 7 to the starting position shown in FIG. 1 again.

This may be set back immediately upon completion of the shutter operation, or may be set back when the mirror is lowered in a single-lens reflex camera, or at any desired point in the design.

To explain this in detail, according to a preset sequential order, when the sensor 49 determines that the shutter operation is completed, the sequential control circuit 51 sends a signal to the magnetic drive circuit 55. Send a signal and magnet 4
7 is intermittently energized. This means that each locking lever 42,
44 engages with the notches 40a, 40b, 41a, 41b in sequence when the locking discs 40, 41 are rotated to recover.

That is, first, when the magnet 47 attracts the iron piece 44b by the first pulse energization, the second locking lever 44 releases the locking disc 41 on the rear curtain side, and at the same time, the second locking lever 44 releases the locking disk 41, and at the same time, the pin The locking lever 42 of No. 1 also comes off from the locking disk 40 on the front curtain side. Then, these curtains 6, 7 return in the opposite direction to the traveling direction while remaining overlapped, and are wound up by the stored force of the springs 14, 16 of each spring drum 3, 4, and return to the starting position. .

At this time, during the return, the notches 40a, 40b, 41 of the locking discs 40, 41 of each curtain 6, 7
Each locking lever 42, 44 engages with a, 41b,
Although it is temporarily stopped, the next pulse energization releases each lock and returns to the starting position. The sensor 48 senses this state and the intermittent energization of the magnet 47 is stopped.

As explained above, the above-mentioned embodiment is advantageous in that it is not necessary to remove the locking lever each time when the shutter curtain starts running, and the shutter curtain can be moved by simply starting the motor. Since the disc flips up the locking lever and the shutter curtain runs, there is concern that this impact may affect the shutter running characteristics, and when returning the shutter curtain to the starting position after closing the shutter, it is necessary to A special operation was required to release it.

From this point of view, the rotating member corresponding to the locking disc is rotated in the opposite direction to the locking direction of the locking lever, and the shutter curtain is prevented from interfering with other members until it passes through the effective exposure range. The present invention has been improved to detect the completion of exposure, move the locking lever away from the locking area, and automatically return the shutter curtain to the starting position.

FIG. 4 is a partially omitted plan view showing an embodiment of the present invention, showing only improved portions based on the embodiment of FIG. 1. This figure shows a configuration in which the leading curtain 6 and the trailing curtain 7 can be returned in a superimposed state at the same time as the shutter curtain running operation is completed without using a magnet for returning the shutter curtain. To explain this simply, the reference numeral 60 in the figure is a small gear provided on the rotating shaft 20 of the front curtain traveling motor 1, and the reference numeral 61 is a large gear that meshes with the small gear and decelerates its rotation. The front curtain 6 is set to rotate exactly one revolution from the start position to the end of its travel. A first lever 63 is provided which has a locking portion 63a that engages with a pin 62 implanted in the side surface of the large gear 61 and is biased by a spring 64. Therefore, the first act 6
When the travel ends, the first foot lever 63 temporarily stops the return.

65 is the rotating shaft 31 of the trailing curtain driving motor 2.
The small gear 66 provided above is a large gear that meshes with the small gear 66 to reduce its rotation, and the reduction ratio of the large gear 66 on the rear curtain side is set to be slightly larger than that on the front curtain side. Therefore, when the trailing blade 7 travels, the pin 67 installed on the side surface of the large gear 66 rotates from the position shown in FIG. 4 to the position indicated by A in the same figure. 6
Reference numeral 8 denotes a second foot lever having a locking portion 68a that engages with this pin 67, and its tip 68b engages with the pin 63 provided on the first foot lever 63.
b. In addition, 69
is a spring that biases this second foot lever 68 clockwise in the figure.

In such a configuration, when the front curtain 6 finishes traveling, the first hook lever 63 engages with the pin 62 of the large gear 61, and its rotation is restricted. Thereafter, the rear curtain 7 travels, and when the travel ends, the pin 67 of the large gear 66 on the rear curtain side reaches the position A in the figure and does not yet engage with the second lever 68. According to this embodiment, this second curtain 7
When the motor 2 on the side rotates a little further, the sensor 49 is set so that the power supply to the motor 2 is cut off. Therefore, the pin 67 rotates the second hook lever 68 counterclockwise due to a slight rotation of the trailing blade 7 of the motor 2 after it has finished running. Then, due to the rotation of this lever 68, the tip end 68b is brought into contact with the first lever 63.
The leading blade 6 is engaged with the pin 63b and rotated counterclockwise to release the restraint of the rotating shaft 20 of the leading blade motor 1, so that the leading blade 6 is returned by the stored force on the spring drum 3 side.

Also, at the time when the restraint of the first curtain 6 is released, the second curtain 7
The power supply to the motor 2 on the side is also cut off by the sensor 49.
As a result, the torque disappears, and the rear curtain 7 is also returned to its original position by the stored force on the spring drum 4 side, and both curtains 6 and 7 are returned to the starting position while remaining overlapped. Then, the start position state shown in FIG. 4 is reached.

(Effects) As explained above, according to the electric focal plane shutter device according to the present invention, in order to run the leading curtain and the trailing curtain, instead of the conventional type that uses spring storage force, the coreless In addition to being a direct drive type using a motor, the return of each curtain to the start position is automatically performed using only the force of the return spring by synchronizing the return of each curtain to the start position and releasing the shutter curtain at the end of travel position in synchronization with the completion of shutter exposure. Since the shutter is configured to return, the leading and trailing curtains can be properly and reliably run and the shutter accuracy can be improved, although the overall configuration is simple. In particular, according to the present invention, the spring precision required for conventional shutter curtain travel is not required, and an extremely weak spring tension that simply returns the shutter curtain to the starting position is sufficient, and power is applied to the coreless motor. There is no need to reverse drive, and energy loss is extremely small. Also, there is no need for transmission members such as gears for spring charge as in the past, and there is no interference from other moving parts. There is no problem that the acceleration performance is impaired. In addition, in the device of the present invention, since the curtain starts running only by starting the coreless motor, the moment of inertia of the lightweight moving coil is sufficient, so the start-up of the curtain running is very good, and the rotation of the motor can be easily controlled. Therefore, by adding a sensor or the like to the curtain traveling speed, it is possible to automatically control the shutter speed and obtain a high-quality shutter speed.

Furthermore, according to the present invention, there is no need for operations related to conventional film winding operations, so even if this is automated, there is no problem such as the need for excessive current at one time, and this makes it possible to reduce the power supply compared to conventional methods. The number and quality of the batteries can be small, and the effect is great.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of a device that is the premise of an electric focal plane shutter device according to the present invention, and FIG. 2 is a side sectional view for explaining the structure of a motor used for curtain travel. FIG. 3 is a system diagram for explaining the control state, and FIG. 4 is a partially omitted plan view showing one embodiment of the present invention. 1, 2...Motor for leading and trailing curtains, 3, 4...
Spring drum for returning to the starting position of the leading and trailing curtains,
6...First curtain, 7...Second curtain, 10...Rotor, 1
4, 16... Spring for return, 61... Large gear, 62... Pin, 63... Foot lever, 66
...Large gear, 67...pin, 68...foot lever.

Claims (1)

[Scope of Claims] 1. An electric focal plane shutter device having a shutter composed of a leading curtain and a trailing curtain that exposes a subject in a forward motion and returns to an initial position in a backward motion, the shutter being connected to the leading curtain. a leading curtain coreless motor that winds up the leading curtain and drives the leading curtain when the leading curtain moves forward; and a rotor that is connected to a ribbon that pulls the trailing curtain; A trailing curtain coreless motor that winds up the ribbon and drives the trailing curtain when the curtain moves forward is disposed in parallel on one side, and a trailing curtain return spring that returns the leading curtain to its initial position; a leading curtain spring drum that is connected to a ribbon that pulls the leading curtain and winds up the ribbon to return the leading curtain to its initial position when the leading curtain returns; and a trailing curtain return spring that returns the trailing curtain to its initial position. and a trailing curtain spring drum that is connected to the trailing curtain and winds up the trailing curtain to return the trailing curtain to its initial position when the trailing curtain returns, and is arranged in parallel with the other, and the coreless leading curtain A leading blade locking disk having a locking portion that locks the rotor of the motor at an initial position of the leading blade and a forward movement end position against the biasing force of the return spring, and a locking portion of this disk. a leading curtain locking means, which includes a leading curtain locking lever that is biased so as to be locked and locks the rotation of the leading curtain locking disk in the return direction; A trailing curtain locking disk having a locking portion that locks the curtain against the biasing force of the return spring at the initial position of the curtain, and a rear curtain locking disk that is biased to be able to lock with the locking portion of this disk and facing the initial position. a trailing curtain locking member that locks the rotation of the trailing curtain locking disk in the return direction at a position and releases the locking of the leading curtain locking disk by the leading curtain locking lever at the forward movement end position of the trailing curtain; a shutter curtain locking means comprising a stop lever; a shutter curtain position detection sensor for detecting the initial position and end position of the leading and trailing curtains; and a coreless motor for the leading and trailing curtains in the initial position in response to a shutter start signal. and electrical control means that energizes the shutter curtain position detection sensor and stops the energization when the shutter curtain position detection sensor detects the end of the forward movement, and in response to the shutter start signal, the leading and trailing curtain coreless motors move the respective locking levers. is sequentially started to rotate in a direction opposite to the direction in which each of the locking disks is locked, and the locking portion of each of the locking disks at its initial position is disengaged from each of the locking levers. The leading and trailing curtains move forward while accumulating the leading and trailing curtain return springs against the biasing force of the leading and trailing curtain return springs, and the leading curtain locking lever The front curtain is locked against the accumulated force by being locked by the locking portion of the front curtain locking disk at the forward movement end position, and the front curtain of the shutter curtain position detection sensor is The leading curtain and trailing curtain coreless motors are de-energized by the trailing curtain forward movement end signal, and in synchronization with the end of the trailing curtain forward movement, the trailing curtain lock release means operates to release the leading curtain locking circle. By releasing the locked state of the plate, each rotor of the leading curtain and trailing curtain coreless motor is rotated by the stored force, and the leading curtain and trailing curtain are wound onto their respective spring drum sides. This electric focal plane shutter device is characterized by: