JP2514326B2 - Electromagnetic drive shutter - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetically driven shutter that drives an open blade group and a closed blade group using an electromagnetic drive device. [Prior Art] In recent years, electronicization of cameras has progressed, and exposure control, charging of a film winding mechanism, operation of a mirror mechanism, and the like have been electrically processed. However, since the conventional shutter uses a spring or the like as the drive source for the shutter blades, a mechanical coupling mechanism and a large amount of electrical energy are required for shutter charging, which is a major disadvantage for electrically controlled cameras. Was there. In view of this, an electromagnetically driven shutter has been proposed and is publicly known, in which a mechanical connection mechanism with the camera body is omitted and the shutter is controlled only by an electric signal and power is saved. [Problems to be Solved by the Invention] However, since the above-mentioned conventional electromagnetically driven shutter is not designed to temporarily hold the shutter blades on the start side, the exposure is an important factor in controlling the exposure time. The start position of the shutter blade during operation is not stable,
There is a problem that it causes the disorder of the exposure time. Further, in the above-mentioned conventional electromagnetically driven shutter, the driving force is immediately transmitted to the shutter as soon as the energization of the electromagnetic driving device is started, so that the shutter is driven. The current has not risen sufficiently, and as shown by the dotted line in FIG. 5, the slit width immediately after the start of exposure running becomes extremely narrow, and there is a problem that exposure failure is likely to occur when high-speed control is performed. . SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide an electromagnetically driven shutter that has a stable exposure time and does not cause poor exposure.

[Means and Actions for Solving Problems]

An electromagnetically driven shutter according to the present invention is connected to an open blade group to allow the open blade group to travel exposed from a closed state to an open state and return to the first set position where the aperture is closed before the next exposure traveling. An open-blade electromagnetic drive device is connected to the closed-blade group to drive the closed-blade group to expose from the open state to the closed state and return to the first set position in which the aperture is opened before the next exposure traveling. The closing blade electromagnetic drive device, the opening blade electromagnetic holding device that holds the opening blade electromagnetic driving device against its driving force at the second set position, which is the start position of the exposure traveling of the opening blade group, and the closing blade group A closing blade electromagnetic holding device for holding the closing blade electromagnetic driving device against the driving force thereof at the second set position which is the start position of the exposure traveling, Prior to the start of the exposure traveling, the electromagnetic force of any one of the electromagnetic drive devices and the electromagnetic holding devices is moved from the first set position to the second set position, and after the elapse of a predetermined time at each second set position, each electromagnetic When the holding device is sequentially demagnetized and the holding force for each of the electromagnetic drive devices is released, the exposure running is performed. [Examples] Hereinafter, the present invention will be described in detail based on one illustrated example. FIG. 1 shows the structure of the main part of the shutter of the present invention, where 1 is a shutter plate having an aperture 1a, and 2 is a shutter plate.
Is an open-blade drive source such as a motor fixed on the shutter plate 1, and 3 has a base fixed to the drive shaft of the open-blade drive source 2 and is connected to one of the support arms of the open-blade group (not shown) at the tip. It is an open blade drive member to which the open pin 3a and the front iron piece pin 3b pivotally supporting the front iron piece 4 are fixed.
Reference numeral 5 denotes a front coil bobbin 6 mounted on the shutter plate 1 so that its position can be adjusted by a front bobbin shaft 6a and a front adjustment eccentric shaft 6b, and a front coil 7 wound around the front coil bobbin 6.
And an open blade electromagnetic holding device (electromagnet) which is inserted into the front coil bobbin 6 and is biased in one direction by the front iron core spring 8 to form an open blade electromagnetic holding device (electromagnet). It is used to control the start position and running timing of the vehicle. Reference numeral 10 is a click spring for positioning the open blade drive member 3 at a position where the front iron piece 4 can be attracted by the attraction force generated by the electromagnetic holding device 5. The distance between the front iron piece 4 and the front coil bobbin 6 is exaggerated from the actual. 12 is a closing blade drive source such as a motor fixed to the shutter plate 1, 13 is a base fixed to the drive shaft of the closing blade drive source 12, and is connected to one of the support arms of the closing blade group (not shown) at the tip. The closed blade 13a and the rear iron piece pin 13b for pivotally supporting the rear iron piece 14 are fixed to the closing blade driving member. Reference numeral 15 denotes a rear coil bobbin 16 mounted on the shutter plate 1 so as to be positionally adjustable by a rear bobbin shaft 16a and a rear adjustment eccentric shaft 16b, a rear coil 17 wound around the rear coil bobbin 16, and a rear coil bobbin 16 fitted and inserted. And a closing vane electromagnetic holding device (electromagnet) composed of a trailing iron core 19 biased in one direction by a trailing iron core spring 18, which controls the start position and operation timing of the closing blade group during exposure operation. Used to do. 20 is a rear iron piece 14 is an electromagnetic holding device 15
This is a click spring for positioning the closing blade drive member 13 at a position where it can be attracted by the suction force generated by. The position of the electromagnetic holding device may be adjusted only on one side, either open or closed. The blade drive source may be a direct type or a linear motor type that does not require a drive member. FIG. 2 shows the control circuit of the above embodiment, SW is a release switch, FF ₁ and FF ₂ are flip-flops, OSM ₁ and OS.
M ₂ , OSM ₃ , OSM ₄ , OSM ₅ , OSM ₆ are one-shot multi, ANDG is AND gate, ORG is OR gate, 22 is delay circuit, 23 is exposure time control circuit, 24 is shutter set circuit, T _{1 to} T ₁₁ is a transistor and E is a power supply. Since the electromagnetically driven shutter according to the present invention is configured as described above, the operation principle will be described with reference to FIG. 3 showing changes in the operating state of each member and FIG. 4 showing the operation sequence. Release switch SW
When the contact piece of is switched from the reset terminal R of the flip-flop FF ₁ to the set terminal S, the output Q of the flip-flop FF ₁ becomes “H”, and the transistor T ₆ becomes conductive due to the rising of the output signal of the one-shot multi-OSM _1. Then, the open blade electromagnetic holding device 5 is excited, and the attraction force attracts the tip iron piece 4. When the output Q of the flip-flop FF ₁ becomes “H”, the output of the one-shot multi-OSM ₂ also becomes “H”, the transistors T ₂ and T ₃ become conductive, and the open blade drive source 2 rotates in the drive direction. However, even if the output of the one-shot multi-OSM ₁ rises and the output of the flip-flop FF ₂ becomes "L" due to the rise of the output signal of the one-shot multi-OSM ₁ , the operation of the delay circuit 22 delays the conduction of the transistor T _{1 and} delays the power supply E.
Therefore, the driving force of the open blade driving source 2 is not generated, and only the suction force of the electromagnetic holding device 5 acts in the initial state. Therefore, as shown in FIG. 3, the front iron piece 4 is attracted to the electromagnetic holding device 5 and the open blade is positioned by the click spring 10 (first set state) from the electromagnetic holding device 5.
Thus, the state is maintained at the start position (second set state). After the delay time elapses, the transistor T ₁
Is conducted and the driving force of the open blade driving source 2 is generated, but the electromagnetic holding device 5 prevents the rotation. Meanwhile, in the initial state is the output of the exposure time control circuit 23 is "L", the output through the inverter is "H", by the output Q of the flip-flop FF ₁ is also "H", the AND gate ANDG Becomes "H", the transistor T ₇ becomes conductive, the closing blade electromagnetic holding device 15 is also excited, and the rear iron piece 14 is also attracted by the attraction force. In addition, the output of the OR gate ORG is also "H", the transistor T _8, T
₉ becomes conductive and the closing blade driving source 12 becomes rotatable in the driving direction. However, as in the above case, since the transistor T ₁ becomes conductive and is not connected to the power source E, the driving force of the closing blade driving source 2 is increased. Does not occur, and the electromagnetic holding device 15
The effect of the suction force of Therefore, as shown in FIG. 3, the rear iron piece 14 is attracted to the electromagnetic holding device 15, and the open blade is held at the start position by the electromagnetic holding device 15 from the state of being positioned by the click spring 20 (first set state). It will be in a state (second set state). Then, after the lapse of the delay time, the transistor T ₁ is turned on and the driving force of the closing blade drive source 12 is generated, but the electromagnetic holding device 15 blocks the rotation thereof. The start positions are respectively determined by the positions of the front coil bobbin 6 and the front iron core 9 and the positions of the rear coil bobbin 16 and the rear iron core 19, and the respective positions are adjusted by the front adjustment eccentric shaft 6b.
Since the adjustment can be performed by the rear adjustment eccentric shaft 16b, the second adjustment can be easily performed. Next, since the transistor T ₆ is cut off and the open-blade electromagnetic holding device 5 is demagnetized by the fall of the one-shot multi-OSM ₁ , the open-blade drive source 2 opens the open-blade drive member 3
Rotates counterclockwise, the open blade group retracts from the shooting optical path, and exposure is started. Then, the output of the one-shot multi-OSM ₂ becomes "L" after a predetermined time, and the open blade drive source 2 stops its operation. At the same time when the output signal of the one-shot multi-OSM ₁ falls, the exposure time control circuit 23 starts timing, and its output becomes "H" after a lapse of a predetermined time. Then, one input to the AND gate ANDG becomes “L” via the inverter, the transistor T ₇ is cut off, and the closing blade electromagnetic holding device 1
Since 5 is demagnetized, the closing blade drive source 12 rotates the closing blade drive member 13 counterclockwise, the closing blade group covers the photographing optical path, and the exposure is completed. In this case, the output of the exposure time control circuit 23 becomes "H" and the input to one input terminal of the OR gate ORG becomes "L" via the inverter, but the output of the one-shot multi-OSM ₃ becomes "H". Then, the other input terminal becomes "H", so that the drive state of the closing blade drive source 12 is maintained. Then, the output of the one-shot multi-OSM ₃ becomes "L" after a predetermined time, and the closing blade drive source 12 stops its operation. When the output of the exposure time control circuit 23 becomes "H" and then becomes "L" through the inverter, the shutter set circuit 24 first waits for a predetermined delay time and then the one-shot multi
The output of OSM ₄ becomes “H”, and the output of one-shot multi OSM ₅ becomes “H” with a certain time difference. When the output of the one-shot multi-OSM ₄ becomes “H”, the transistor T ₄ ,
T ₄ is turned on, open the blade drive source 2 is operated in the set direction,
A state in which the open blade group covers the shooting optical path (first set state)
Return to After that, when the output of the one-shot multi-OSM ₅ becomes “H”, the transistors T ₁₀ and T ₁₁ become conductive, the closing blade driving source 12 operates in the set direction, and the closing blade group retracts from the photographing optical path (first). Set state). Then, when the output signal of the one-shot multi-OSM ₅ becomes "L", the output of the one-shot multi-OSM ₆ becomes "H" via the inverter, and the flip-flop FF ₂ is reset and its output becomes "H". since the cut off transistors T ₁ output becomes "L" of the delay circuit 22, the energization of the driving source 2, 12 is cut off, the set is completed. The operation principle of the electromagnetically driven shutter of the present invention has been described above. However, since each blade group is held by the electromagnetic holding means for a predetermined time at the start of the exposure operation, the start position of the shutter blade is stable and the exposure time is stable. .
Further, since the holding is released after a predetermined time has passed after the start of energization to the electromagnetic drive device, the shutter blades are started after the drive current to the electromagnetic drive device has risen sufficiently. Therefore, as shown in FIG. 5, there is no delay in the rise of the drive current as compared with the conventional example, so that the blade traveling characteristics have an initial inclination, and as a result, there is an open blade group and a closed blade group immediately after the start of exposure. Since the slit width D is D> d compared to the slit width d of the conventional example, the traveling speed immediately after the start of exposure does not slow down, so-called exposure failure such as unexposed or uneven exposure does not occur, and the shutter speed is increased. Is possible. Further, since the characteristic curve becomes close to a straight line and the traveling time is shortened, it is possible to reduce the distortion of the image when photographing the moving body. In this embodiment, only the attraction force of each electromagnetic holding device 5, 15 was used to attract each iron piece 4, 14 attached to each blade drive member 3, 13 to each iron core 9, 19. However, at this time, if a driving force in the set direction is applied to the electromagnetic drive sources 2 and 12, each blade group can be more reliably held at the start position. FIG. 6 shows the structure of the essential part of another embodiment. To explain this, 26 is a pre-locking lever pivotally mounted on the shutter plate 1 and provided with a right-handed habit by a spring 27. The front iron piece 4 is pivotally attached to one end of the open blade driving member 3 via a pin 26a, and the other end is a pin of the open blade drive member 3.
A hook portion 26b capable of engaging with 3c is formed. Reference numeral 28 denotes a rear locking lever pivotally mounted on the shutter plate 1 and provided with a right turning property by a spring 29. A rear iron piece 14 is pivotally mounted on one end of the rear iron piece 14 via a pin 28a and the other end thereof. Has a hook portion 28b which can be engaged with the pin 13c of the closing blade drive member 13. At the time of shutter release, in the state shown in FIG. 6 (first set state), the opening blade drive source 2 and the closing blade drive unit 12 are respectively provided with a driving force in the setting direction to open the opening blade drive member 3 and the closing blade drive member 13. The front locking lever 26 and the rear locking lever 28 are rotated counterclockwise by rotating the front locking piece 4 and the front locking piece 4 respectively.
And the rear iron pieces 14 are brought into contact with the front iron cores 9 and the rear iron cores 19 of the electromagnetic holding devices 5 and 15, respectively, and the electromagnetic holding devices 5 and 15 are excited one after another to excite the front iron pieces as shown in FIG. 4 and rear iron pieces
The front locking lever 26 and the rear locking lever 28 are respectively held by adsorbing 14 (second set state). After this holding is completed, the open blade driving source 2 and the closing blade driving source 12 are respectively given a driving force in the exposure operation direction to rotate the open blade driving member 3 and the closing blade driving member 13 counterclockwise, respectively.
Both drive members 3 and 13 are hooked by hooks 26b-pins 3c and hooks 28b-pins 1 by a front locking lever 26 and a rear locking lever 28, respectively.
It is immediately locked by the engagement relationship of 3c (Fig. 8), and this position becomes the start position. The outputs of the electromagnetic holding devices 5 and 15 are set so that the front locking lever 26 and the rear locking lever 28 are not rotated rightward by the driving force of the open blade driving source 2 and the opening / closing blade driving source 12, respectively. Be present. In the above embodiment, in order to hold the front locking lever 26 and the rear locking lever 28 by the electromagnetic holding devices 5 and 15, respectively, a driving force in the set direction is applied to the electromagnetic drive sources 2 and 12 to set the front iron piece 4 and the rear iron piece. I moved the iron piece 14 to the adsorption possible position,
If the first set position is set to the adsorbable position in advance, it can be held only by the adsorbing force of the electromagnetic holding devices 5 and 15. After that, first, the electromagnetic holding device 5 is demagnetized, and the front locking lever 26 is rotated rightward by the tension of the spring 27 to rotate the hook 26b.
As the pin 3c is released from the lock, the open-blade drive member 3 is rotated counterclockwise by the driving force of the open-blade electromagnetic drive source 2 in the exposure operation direction, and the open-blade group is retracted from the photographing optical path to start exposure. It Then, after the set exposure time elapses, the electromagnetic holding device 15 is demagnetized, the rear locking lever 28 is rotated right by the tension of the spring 29, and the pin 13c by the hook portion 28b is rotated.
When the lock is released, the closing blade drive member 13 rotates counterclockwise by the driving force of the closing blade electromagnetic drive source 12 in the exposure operation direction, the closing blade group covers the photographing optical path, and the exposure is completed. The subsequent setting operation is basically the same as that of the above-mentioned embodiment, and the driving force in the setting direction is sequentially applied to the open blade electromagnetic driving source 2 and the closing blade electromagnetic driving source 12 to set each member to the first setting state (first It is made by bringing it to (Fig. 6). FIG. 9 shows a control circuit suitable for the other embodiment described above, in which the output Q of the flip-flop FF becomes "H" by switching the release switch SW, so that the transistor T
₁ is immediately turned on, and power can be supplied to the electromagnetic drive sources 2 and 12. Further, since the output of the exposure time control circuit 23 is "L" in the initial state, as described above,
Since the outputs Q and FF of the FF become “H” and “L” respectively, the output of the one-shot multi OSM ₁ rises and the output of the NOR gate NORG becomes “L”, which causes the electromagnetic drive sources 2 and 12 to operate. At the same time as applying the driving force in the set direction and exciting the electromagnetic holding devices 5 and 15 one after another, the driving force in the exposure operation direction is applied to the electromagnetic driving source 2 by the fall of the input signal of the one-shot multi-OSM _1. to start counting of the exposure time control circuit 23, the electromagnetic holding device by the fall of the one-shot multi-OSM ₁ via the inverter the set one-shot multi-OSM ₂ of the output signal after a predetermined time by the falling of the output signal 5 Demagnetize. Then, after a predetermined time, the output of the exposure time control circuit 23 becomes "H", thereby applying a driving force in the exposure operation direction to the electromagnetic drive source 12, and the output of the exposure time control circuit 23 becomes "H". The electromagnetic holding device 16 is demagnetized by the fall of the output signal of the set one-shot multi-OSM ₃ after a predetermined time, and the output of the exposure time control circuit 23 becomes "H". 24 outputs of one-shot multi OSM ₄ and OSM ₅ are set to "H" after different delay times, and electromagnetic drive source is supplied via OR gates ORG ₁ and ORG _2.
The driving force in the set direction is sequentially applied to 2 and 12. FIG. 10 shows an operation sequence of the other embodiment described above. Since this embodiment is constructed as described above, in addition to the advantages common to the first embodiment, since the drive member is not provided with an iron piece, the inertia is small and the mechanical follow-up delay is small, so that the blade is small. There is an advantage that the initial inclination of the traveling characteristics is further raised, and as a result, the width of the photographing slit can be further widened, so that the shutter speed can be further increased. Further, by making the length of the arm portion on the iron piece pivotally attached side of the locking lever longer than the length of the arm portion on the hook side, the attraction force of the electromagnetic holding device for obtaining a predetermined locking force by this principle is set. It has the advantage that it can be made smaller and consequently the electrical energy required can be made smaller. In both of the above-mentioned embodiments, a normal electromagnet is used to secure the exposure operation position of each blade group and control the timing of running start, but an electromagnet with a permanent magnet (combination type) or an electrostrictive element is used. It is also possible. For example, when an electromagnet with a permanent magnet is used, the drive member or the locking lever can be attracted and held in the first set state, and that position can be set as the start position.
It is easier to simplify the mechanism. In addition, it is effective to save power because it is sufficient to apply a current so that the iron pieces separate from each other only at the start of exposure. [Effects of the Invention] As described above, the electromagnetically driven shutter according to the present invention has a practically important advantage that the exposure time is stable, exposure defects such as exposure unevenness do not occur, and as a result, speedup is possible. Have

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a main part of an embodiment of an electromagnetically driven shutter according to the present invention, FIG. 2 is a diagram showing a control circuit of the above embodiment, and FIG. 3 is an operating state of each member of the above embodiment. FIG. 4 is a diagram showing a change, FIG. 4 and FIG. 5 are diagrams showing an operation sequence and a blade traveling characteristic of the above embodiment, respectively, and FIG. 6 is a diagram showing a configuration of a main part of another embodiment, FIG. FIG. 8 is a diagram showing changes in the operating state of each member of the other embodiment, and FIGS. 9 and 10 are diagrams showing a control circuit and an operating sequence of the other embodiment, respectively. 1 ... Shutter plate, 2 ... Open blade drive source, 3
...... Open blade driving member, 4 ... Lead iron piece, 5 ... Open blade electromagnetic holding device, 10 ... Click spring, 12 ... Closed blade drive source, 13 ... Closed blade drive member, 14 ... Rear iron piece, 15 ……
Closed-blade electromagnetic holding device, 20 ... click spring, 22 ... delay circuit, 23 ... exposure time control circuit, 24 ... shutter set circuit, SW ... release switch, FF, FF ₁ , FF ₂ ...... flip-flop , OSM _{1 to} OSM ₆ ... One-shot multi,
ANDG …… AND gate, ORG, ORG ₁ , ORG ₂ …… OR gate, NORG …… NOR gate, T _{1 to} T ₁₁ …… Transistor, E …… Power supply.

Continuation of the front page (56) Reference JP-A-55-149924 (JP, A) JP-A-60-208739 (JP, A) JP-A-58-190930 (JP, A) Actual development Sho-60-181729 (JP , U)

Claims (1)

(57) [Claims] 1. An open-blade electromagnetic device connected to an open-blade group to cause the open-blade group to travel exposed from a state where the aperture is closed to a state where the aperture is open and to return the aperture to the first set position where the aperture is closed before the next exposure traveling. A drive unit and a closing blade electromagnetic connected to the closing blade group to cause the closing blade group to travel exposed from the open state to the closed state and to return to the first set position where the aperture is opened before the next exposure running. A drive device; an open-blade electromagnetic holding device for holding the open-blade electromagnetic drive device against its driving force at a second set position, which is the start position of the open-blade group exposed travel; A closing blade electromagnetic holding device for holding the closing blade electromagnetic driving device against its driving force at the second set position, which is a start position, and The electromagnetic holding device is moved from the first set position to the second set position by an electromagnetic force of any one of the electromagnetic drive devices and the electromagnetic holding devices, and the electromagnetic holding devices are sequentially moved after a predetermined time elapses at each of the second set positions. An electromagnetically driven shutter, characterized in that the vehicle travels exposed when the holding force for each electromagnetically driven device is demagnetized.