JPH0472211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric focal plane shutter device.

A conventional focal plane shutter is constructed so that energy for driving 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 that rotates in conjunction with a film winding mechanism and a spring drum that is biased in one direction by a spring means such as a coil spring. The winding is carried out from the 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 the required current would be extremely large, causing problems with the number and quality of batteries. Therefore, it is desired that some kind of countermeasure be taken from this aspect as well.

The present invention has been made in view of the above-mentioned circumstances, and the shutter curtain of the shutter, which exposes the subject by forward movement and returns to the initial position by backward movement, is moved forward by using the rotational power of a coreless motor. , a mechanically independent direct drive type shutter mechanism capable of returning the shutter curtain to its initial position by the spring force accumulated during this forward movement, and each shutter curtain is positioned between the forward movement end position and the initial position. By providing a locking means that can lock the shutter curtain, when the shutter curtain is moved forward, the locking means can be automatically released by rotating the coreless motor for easy and appropriate control. In addition, by simply releasing the locked state by the locking means after the forward movement is completed, the coreless motor can be rotated by the stored force of the spring, and the shutter curtain can be automatically returned to the initial position. Despite its simple configuration,
An object of the present invention is to provide an electric focal plane shutter device that can improve shutter accuracy.

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

FIG. 1 shows an embodiment of an electric focal plane shutter device according to the present invention, and shows the state before the shutter is started, which is the opposite state from the conventional device.

In the figure, numerals 1 and 2 are coreless motors arranged in parallel for driving the rear curtain, and numerals 3 and 4 oppose these motors 1 and 2 to return the shutter curtain to its initial position (start position). These four drums 1, 2, 3,
4 are erected immediately in front of the film plane (focal plane) 5, facing to the left and right of the film plane (focal plane) 5. The leading curtain 6 and the trailing curtain 7 are stretched between the motors 1 and 2 and the spring drums 3 and 4, respectively, and are placed at initial positions.

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 urged 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 arranged 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 a non-magnetic material so as not to affect the magnetic field of the motor 1.

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 the present invention, when the first and second curtains 6, 7 finish running, the rotation shafts 2 of the motors 1, 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
The locking lever is biased counterclockwise in the figure by a spring 43, that is, toward the locking disc 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 disk 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 pasted on these connecting plates 11 and 17, respectively, and the sensors 48 and 49 are connected to Hall elements. By configuring the switch, it operates as a proximity switch, making it possible to detect the respective positions. 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 will be explained in accordance with the operating order of the device of the present invention including this control state. In the state shown in FIG. 1, the connection plate 11 is , 17 are both sensed by the sensor 48, and it is determined that this is before the shutter starts.

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, when it is determined by the sensor 49 that the shutter operation is completed according to the preset sequential order, the sequential control circuit 51 sends the magnetic drive circuit 55. Sends a signal to 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 and 7 return to the opposite direction from when running while remaining overlapped, and are wound up by the stored force of the springs 14 and 16 of each spring drum 3 and 4, and return to the starting position. return.

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, according to the electric focal plane shutter device according to the present invention, the rotary power of the coreless motor is used to move the shutter curtain forward, and the spring force stored during this forward movement is used to move the shutter curtain forward. A mechanically independent direct drive type shutter mechanism capable of returning the curtain to its initial position is provided, and a locking means capable of positioning and locking each shutter curtain at the forward end position and the initial position is provided. Therefore, although the overall configuration is simple,
The leading and trailing curtains can be moved properly and reliably by simply rotating the coreless motor by releasing the locking means, and can be stopped and locked at a desired position, improving shutter accuracy. be able to.

In particular, according to the present invention, when the shutter curtain is moved forward, the locking means can be automatically released by simply rotating the coreless motor, and the shutter curtain can be moved forward, and the shutter curtain can be moved forward at each forward movement end position. By being locked by the locking means and releasing the locked state, the coreless motor is not driven.
Appropriate and reliable drive control of the shutter curtain can be performed in which the shutter curtain automatically returns to its initial position by the stored spring force. At this time,
The spring for returning the curtain has an extremely weak biasing force, does not require precision, has little energy loss, and is less likely to be a load on the motor for moving the curtain forward.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing an embodiment of an electric focal plane shutter device according to the present invention, and FIG.
The figure is a side sectional view for explaining the structure of a motor used for curtain traveling, and FIG. 3 is a system diagram for explaining its control state. 1, 2...Motor for leading and trailing curtains, 3, 4...
Spring drum for returning to the starting position of the leading and trailing curtains,
5...Film plane (focal plane), 6...First curtain, 7...
... Rear curtain, 10 ... Rotor, 14, 16 ... Return spring, 20, 31 ... Rotating shaft.

Claims (1)

[Scope of Claims] 1. A shutter comprising a front curtain and a rear curtain that exposes a subject in a forward motion and returns to an initial position in a backward motion; a rotor connected to the front curtain; a leading curtain coreless motor that winds up the leading curtain and drives the leading curtain when the trailing curtain moves forward, and a rotor connected to a ribbon that pulls the trailing curtain, and winds up the ribbon when the trailing curtain moves forward. It has a trailing curtain coreless motor that drives the trailing curtain, and a leading curtain return spring that returns the leading curtain to its initial position, and is connected to a ribbon that pulls the leading curtain, and is connected to a ribbon that pulls the leading curtain to move the ribbon when the leading curtain returns. a leading curtain spring drum for returning the leading curtain to the initial position; and a trailing curtain return spring for returning the trailing curtain to the initial position; a leading curtain spring drum that winds up the curtain and returns the trailing curtain to its initial position; a rotor of the leading curtain and trailing curtain coreless motor;
A trailing blade locking disk having a locking portion that locks the trailing curtain against the biasing force of the return spring at the initial position and forward movement end position, and locking of each of these locking disks. a locking means comprising a pair of locking levers that are biased so as to be selectively locked to the respective locking discs and lock the rotation of the respective locking disks in the return direction; and A shutter curtain position detection sensor that detects the position and a travel end position, and a shutter start signal that energizes the leading and trailing curtain coreless motors at the initial position, and when the shutter curtain position detection sensor detects the end of forward movement, energizes. and an electric control means for stopping each of the locking discs in the locking means after receiving a forward movement end signal of the leading curtain and trailing curtain from the shutter curtain position detection sensor, and after the forward movement of the leading curtain and trailing curtain is completed. The locking lever that locks the locking portion at the forward movement end position is moved in the locking release direction, and the leading curtain and trailing curtain are returned to their initial positions by the urging force of the return spring. the front curtain and rear curtain coreless motors are arranged in parallel on one side, and the front curtain and rear curtain spring drums are arranged in parallel on the other side, and the front curtain is activated by a shutter start signal. , the trailing curtain coreless motor is sequentially started to rotate in a direction opposite to the direction in which each of the locking levers locks each of the locking disks, and locks each of the locking disks at the initial position. When the parts are disengaged from the locking levers, the leading and trailing curtains move forward while accumulating the springs for returning the leading and trailing curtains against the biasing force of the springs for returning the leading and trailing curtains. At the same time, each of the locking levers is locked with the locking portion of each of the locking disks at the forward movement end position, so that the leading curtain and the trailing curtain are moved to the stored force. At the same time, the leading and trailing curtain coreless motors are de-energized in response to a forward movement end signal of the leading and trailing curtains from the shutter curtain position detection sensor, and the leading and trailing curtains are stopped in motion. After the movement is completed, the locking release means operates to release the locking state of each locking disk, thereby rotating each rotor of the leading blade and trailing blade coreless motors with the stored force, and causing the leading blade to rotate. An electric focal plane shutter device characterized in that a trailing curtain is wound around each spring drum.