JPS6158014B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a malfunction warning device for an electric shutter that utilizes an electromagnetic device combined with a permanent magnet.

As shown in Fig. 3, as an electromagnetic device for controlling the closing of an electric shutter, it is possible to eliminate the need for a holding member for the iron piece lever 3, and the coil L is energized when controlling the closing of the shutter, and when the shutter is in the open state. A type in which a permanent magnet is combined with the iron core 1 has come to be used, taking advantage of advantages such as not needing to supply power to the coil L for holding the iron core 1.

In addition, the mechanical and electromagnetic operation delays of the shutter opening control system and closing control system can be offset,
In order to facilitate electrical control, it has been considered to use the same type of electromagnetic device for opening control as for closing control.

Here, the strength of the attraction force of the permanent magnet 2 that holds the iron piece lever 3 against the separation force of the spring 4 influences the magnitude of the electric power applied to the coil L when the iron piece lever 3 is moved away from the iron piece lever 3. Therefore, it is limited to the extent that the iron piece lever 3 can be held while withstanding the impact that normally occurs.

Therefore, since the setting member (not shown) is separated from the iron lever 3 after the shutter is set, if an unexpected shock is applied to the camera, the iron lever 3 may become separated from the iron core 1. It may be left in the same state as before the set.

If you press the shutter button without knowing the status and take a picture, either a camera equipped with an electric shutter that closes the shutter using the electromagnetic device described above, or a camera equipped with an electric shutter that opens and closes the shutter. If one or both of them are malfunctioning, depending on the type of shutter and their respective conditions, no actual shooting will take place at all, wasting a frame of film and making it impossible to retake an important photo. Otherwise, the film frame facing the aperture and, in some cases, the frames on both sides of the aperture are exposed, making it impossible to take a picture at that time, and also causing failure in previous and subsequent pictures.

Therefore, the present invention aims to reduce the electromotive force generated in the coil by the release when the iron piece lever in the electromagnetic device on the shutter release control side separates from the iron core and the release is performed. It is used as a signal to forcibly drive the coil on the closing control side to perform the closing release as well, thereby preventing the adverse effects of exposure on other film frames.
A combination of permanent magnets that enables the next reset, and also allows the shutter to notify the photographer that an abnormal operation has occurred in the past by eliminating the shutter's operating sound when the shutter is operated. The present invention provides a security device for a camera with an electric shutter that utilizes an electromagnetic device.

Embodiments of the present invention will be described below based on the drawings.

Figure 1 shows a control circuit when the above electromagnetic device is used to control the opening and closing of the shutter.When the iron piece lever on the opening control side separates from the iron core before operating the shutter, the shutter closes and closes. This is done to close the shutter.

First, the capacitor C ₂ is always charged to the open circuit voltage of the current battery E ₀ via the current limiting resistor R ₂ and the reverse current prevention diode D ₂ . Therefore,
Can drive the coil Lc on the shutter closing control side
The circuit consisting of the SCR and transistors T ₅ and T ₆ is always in a state where it can constitute a power supply circuit.

Therefore, if the iron piece lever on the release control side of the shutter separates from the iron core after the shutter is set but before the release operation, an electromotive force is instantaneously generated in the coil Lo. This electromotive force pulse is then AC amplified by transistor T ₃ via resistor R ₃ and capacitor C ₃ to trigger the SCR. As a result, transistors T ₅ and T ₆ become conductive due to the charge of capacitor C ₂ , and the coil also becomes conductive.
A large current is instantaneously passed through Lc, causing the shutter to close and release.

Therefore, the shutter can be reset, and the next time the shutter is operated, the mirror will be raised and lowered quickly, and the shutter will not make any noise, so the photographer will not have to worry about any previous abnormal shutter operation. By knowing this, you can properly take pictures by operating the release after resetting the shutter.

In addition, in this closing operation, capacitor C ₂
When the charge on the capacitor C2 is discharged to a certain potential, the SCR is cut off, so the current from the power source _E0 does not continue to flow, and the current stops flowing when the capacitor _C2 is charged to the open circuit voltage.

Next, if the iron piece lever is normally attracted, press the release button and first close the power switch S _1. As a result, the transistor T ₄ becomes conductive and the gate of the SCR is connected to the power source E ₀ . Disable the SCR by pulling it down to a negative level. Subsequently, the mirror is raised and the release switch _S2 is switched from terminal a to terminal b. Therefore, the flip-flop _FF1 is set when the reset is released, the output Q is inverted to the "H" level, and the output is inverted to the "L" level. This results in a transistor
Since T ₁ conducts through the buffer B ₁ , the coil L ₀ for opening the shutter is connected to the capacitor C ₁
A large current is instantaneously supplied by the charged load, causing the iron piece lever to separate from the iron core and open the release. At this time, an electromotive force similar to that described above is generated in the coil Lo, but as described above, the SCR cannot conduct.

On the other hand, since the field effect transistor FET is cut off due to the inversion of the output of the flip-flop _FF1 , charging of the capacitor _C4 is started via the exposure time control resistor _R4 . and comparator
COM is inverted when the potential at the non-inverting input (+) due to charging of the capacitor C ₄ becomes higher than the potential at the inverting input (-), causing the transistor T ₂ to conduct through the buffer B ₂ . Coil Lc is therefore actuated by the discharge of capacitor _C2 , causing the closing release of the shutter as described above.

Next, Figure 2 shows the control circuit when the up and down of the mirror is also controlled electromagnetically using a plunger, where Lu is the solenoid on the up release side and L _D is the solenoid on the down release side. It is a solenoid. In addition, terminals c, d, and e are always connected to a power source (not shown), and when the iron piece lever separates from the iron core before release, the down release of the mirror and, in some cases, the closing release of the shutter are performed. It is something that can be done.

That is, when the iron piece lever on the open release side separates from the iron core, an electromotive force is generated in the coil Lo, which triggers the SCR through the differential circuit of the capacitor C ₅ and the resistor R ₅ and the diode D ₃ . Therefore, the transistor T ₆ ' conducts to energize the shutter closing release coil Lc, and the transistors T ₅ and T ₉ conduct to energize the mirror down-release solenoid _LD . let

Also, if the iron piece lever on the closed release side rather than the open release side separates from the iron core, the coil
An electromotive force is generated in Lc and triggers the SCR through the differential circuit of capacitor _C6 and resistor _R6 and diode _D4 , so that the solenoid _LD is energized.

In any of the above cases, the solenoid _LD for the mirror down release is energized, but this is not directly related to the present invention, but the mirror down drive is activated by the energization of the solenoid _LD . The present invention is designed to be applicable to a type of camera in which the shutter cannot be set unless the member is moved to the position where the mirror is raised or the mirror is raised.

If it is set correctly, when you press the release button, the power switch is first closed and voltage is supplied to each part of the circuit, transistor _T4 becomes conductive, and the gate of the SCR drops to the "L" level. ,
Make the SCR inoperable. Then switch S ₃ is switched from terminal a to b, flip-flop
FF ₂ is set when the reset is released, and counters CO ₁ , CO ₂ , and CO ₃ are also released from reset.

Therefore, the flip-flop _FF2 inverts the output Q to the "H" level, opens the AND gate _AND1 , and sends the clock pulse CP to the counter _CO1 . In the initial state, the outputs Q ₃ , Q ₄ , and Q ₅ of the counter CO ₁ are at the "L" level and the output of the NOR gate NOR ₁ is at the "H" level, so the output Q ₂
When the is reversed to “H” level, the AND gate
The output of AND ₂ is inverted to the "H" level, making the transistor T ₇ conductive via the buffer B ₃ and energizing the solenoid Lu for raising the mirror. This activates the mirror-up drive member to raise the mirror. After that, when the output Q ₅ of the counter CO ₁ is inverted to the "H" level and the output Q ₂ is inverted to the "H" level, that is, after the operation of the automatic diaphragm mechanism has stopped, the output of the NAND gate NAND ₁ is The signal is inverted to the "L" level, and the transistor T ₁ ' is made conductive via the buffer B ₁ to energize the shutter release coil Lo. Furthermore, when the output Q ₅ of the counter CO ₁ is inverted to the "H" level and the output Q ₃ is inverted to the "H" level, the output of the AND gate AND ₃ is inverted to the "H" level, and the inverter I If you close the AND gate AND ₁ through ₁ , it will be fixed in that state.

Also, since the AND gate AND ₄ is opened by the inversion of the AND gate AND ₃ , the clock pulse CP
is fed into the counter CO ₂ . If the exposure time setting switch S ₄ is connected to the output Q ₁ and the frequency of the oscillator OSC is f = 1KHz (1.024KHz), the output will change after 1ms or 1/1000 seconds.
_Q1 is inverted to the "H" level, and counter _CO2 is fixed in that state by closing AND _{gate AND4 via} inverter I2. On the other hand, at this time, the output of the NAND gate NAND ₂ is inverted to the "L" level and makes the transistor T _{2 '} conductive via the buffer B 2, so that the shutter closing/release coil Lc is energized. On the other hand, the AND gate _AND5 is opened and the clock pulse CP is sent to the counter _CO3 . In the operation of the counter _CO3 , first, when the output of the output _Q3 is reversed to the "H" level, the output of the NOR gate _NOR2 is reversed to the "L" level and the current supply to the coil Lc is stopped. Next, output _Q4 is inverted to "H" level and output
When Q ₂ is inverted to the "H" level, the output of the AND gate AND ₆ is inverted to the "H" level, which makes the transistor T ₈ conductive through the buffer B ₄ and energizes the solenoid L _D for down-release of the mirror. Have them do it. This activates the mirror-down drive member to lower the mirror. After that, when the output Q ₄ of the counter CO ₃ is inverted to the "H" level and the output Q ₃ is inverted to the "H" level, the output of the NAND gate NAND ₃ is inverted to the "L" level and the AND gate AND is inverted. When ₅ is closed, it is fixed in that state.

As described above, in a camera with an electric shutter that uses an electromagnetic device combined with a permanent magnet, the iron piece lever in the electromagnetic device on the shutter release control side separates from the iron core before release, and the release is performed. If the film is released, the electromotive force generated in the coil due to the separation is used as a signal to forcibly drive the coil on the closing control side to perform the closing release. In addition to preventing the negative effects of exposure to
When the shutter release operation is subsequently performed, the shutter does not make any operating noise, which allows the photographer to know that an abnormal operation occurred previously, and to prompt the photographer to set the shutter again and shoot properly. It is possible.

[Brief explanation of the drawing]

FIGS. 1 and 2 are circuit diagrams showing embodiments of the present invention, and FIG. 3 is an explanatory diagram of an electromagnetic device that is the premise of the present invention. 1... Iron core, 2... Permanent magnet, 3... Iron piece lever, 4... Spring, L (Lo, Lc)... Coil.

Claims (1)

[Scope of Claims] 1. An iron piece lever serving as a release member that is given a disengagement habit is attracted to an iron core by the attractive force of a permanent magnet, and a magnetomotive force is generated in a coil in the direction of reducing the magnetic flux of the permanent magnet. In a camera with an electric shutter that uses an electromagnetic device that moves the lever away from the shutter to control the opening and closing of the shutter, an opening capacitor and a closing capacitor that are constantly connected to a power source and charged, and a release operation signal are used. an opening switch means for forming a closed circuit between the opening coil and the opening capacitor in the opening control electromagnetic device; and an opening switch means that is activated by the release operation signal and generates an exposure time end control signal after a predetermined time. an exposure time control circuit; a first closing switch means configured to configure a closed circuit between a closing coil in the closing control electromagnetic device and the closing capacitor according to a control signal of the exposure time control circuit; a differentiating circuit connected to both ends of the opening coil and detecting an electromotive force instantaneously generated in the coil when the iron piece lever in the opening control electromagnetic device separates from the iron core; a second closing switch means for configuring a closed circuit between the closing coil and the closing capacitor; and a prohibition circuit for disabling the closed circuit configuration function of the second closing switch means in response to a release operation signal. A security device characterized by comprising the following.