JPS61120125A - Electromagnetic shutter - Google Patents

Abstract

PURPOSE:To make an electromagnetic shutter compact and to control it through an electric interface by charging and releasing the shutter with plural pulses and controlling the seconds of automatic exposure according to variation in the length of a final pulse. CONSTITUTION:When a changeover switch S1 is on, an electromagnet is controlled by a pulse oscillation circuit to attract and release an iron piece 10c repeatedly. Then, a driving ring 10 is swiveled clockwise and counterclockwise repeatedly to swivel a closure ring 5 gradually through the operation of a ratchet claw 12 and a lock claw lever 14, thereby charging a closure spring 6. Then, the ring 5 is operated counterclockwise with the final pulse of a charging stroke to push an engaging contact pin 18c to left with its edge 5c. Then, a lever 18 is swiveled counterclockwise to disengage an opening/closing ring 2 and the switch S1 is turned off. Therefore, the ring 2 is opened and swiveled counterclockwise through the operation of the spring 3 to open shutter blades 4; and the electromagnet is controlled by an exposure second control circuit to maintain the iron core 10c in an attracted state.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an Everset type electromagnetic shutter.

Normal everset type shutters (a type of shutter release that is automatically performed at the final operation of the charging process) have a longer release stroke and require electrical control due to the mechanical connection. The problem is that it is impossible. On the other hand, conventional electric shutters of the electromagnetic release type require a mechanical setting member, which increases the load when winding the film, and there is a problem in that there is no freedom in camera design due to constraints caused by this. On the other hand, the electromagnetic shutter type requires a high-output electromagnet because it divides within the -pulse, and as a result, a permanent magnet,
There are problems in that the printed circuit board becomes larger, higher in cost, and heavier.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention aims to provide an electromagnetic shutter that can be made compact and that can be controlled entirely through an electrical interface.

1-Ai The electromagnetic shutter according to the present invention operates an electromagnetic drive device using multiple pulses to charge and release the shutter, and also controls the automatic exposure time by changing the final pulse length of the multiple pulses. In this way, the electromagnetic drive device is miniaturized by dividing the amount of safety torque, and one electromagnetic drive device can perform all the controls.

Hereinafter, the present invention will be described in detail based on an illustrated embodiment. Fig. 1 is a plan view showing the structure of the lid of the present invention, where ■ is a substrate having an aperture 1a, and 2 is a substrate. an opening/closing ring which is rotatably disposed on the aperture la and has a retaining portion 2a formed at a predetermined position, and has an engaging pin 2b and a trigger switch operating pin 2C implanted therein; 3 is an opening spring that gives the opening/closing ring 2 a left rotation behavior (opening behavior), and 4 is a pair of opening/closing rings that are connected to the opening/closing ring 2 by a pin-slot connection and are opened and closed by left and right rotation of the opening/closing ring 2. A shutter blade 5 that also serves as an aperture (only one blade is shown for convenience of drawing) is disposed on fIvLl so as to be rotatable in the same capacity as the aperture 1a, and also has an arcuate ratchet gear portion 5a. A closing ring whose one end edge 5b can engage with the engagement pin 2b, and 6 a closing spring that gives the closing ring 5 a dextrorotating behavior (closing behavior). It is assumed that the elasticity of the closing spring 6 is set to be stronger than the elasticity of the opening spring 3. Reference numeral 7 denotes a delay ring which is rotatably disposed on the substrate 1 in the same manner as the aperture la and has an arcuate rack portion 7a and an arcuate hole 7b through which the engagement pin 2b is fitted. , 8 is a return spring that imparts dextrorotary behavior (return behavior) to the delay ring 7, and 9 is an arcuate rack portion 7 provided on the substrate 1.
It is assumed that the elasticity of the return spring 8 is set to be significantly weaker than the elasticity of the opening spring 3. Mg is an electromagnet fixed on the substrate l, 10 is arranged on the substrate 1 so as to be rotatable in the same capacity as the aperture la, and one arm portion 10a, the other arm portion 10b, and the other arm portion 1.
A drive ring 11 has an iron piece 10c fixed to the iron piece 0b and is made to rotate to the left by being pulled by the electromagnet Mg, and 11 imparts right-handed rotation behavior to the drive ring lG. A spring 12 is pivotally attached to the arm 10a, and a spring 13 (suspended between it and the arm 1a) imparts dextrorotation, and the distal end edge is bent downward. a ratchet pawl 14 provided with a portion 12a and whose tip engages with the ratchet gear portion 5a;
is pivotally mounted on the substrate 1 and has an upwardly bent portion 14a near the base.
A locking pawl lever 15 is provided with a tip end side edge that engages with the lower bent portion 12a from the inside and a tip end that engages with the ratchet gear portion 5a, and a locking pawl lever 15 imparts right-handed rotation behavior to the locking pawl lever 14. A spring 16 is pivotally connected to the arm tob, and a spring 17 (suspended between the arm 10b and the arm 10b) imparts right-handed rotational behavior and engages with the upper bent portion 14a. A locking lever 18 provided with a locking portion 16a is pivotally mounted on the base plate 1 and has a locking lever 16 at its tip.
An upper bent portion 18a capable of inhibiting left rotation of the closing lever 5 and an engaging pin 18b capable of being engaged with the #A green 5c are provided, and an engaging portion 18C capable of engaging with the retaining portion 2a is provided at a midway portion. and a change-over switch actuating pin 18d, and 19 is a spring that gives the locking lever 18 a right-handed tendency. The elasticity of the spring 15 is set to be weaker than the elasticity of the spring 11, and the elasticity of the spring 19 is set to be stronger than the elasticity of the spring 17. The locking lever 18
A normally closed changeover switch that turns OFF when the S
! is a normally open type trigger switch whose one contact piece engages with the trigger switch operating pin 2C and is turned OFF by turning the opening/closing ring to the left, and these are incorporated in the control circuit described later together with the electromagnet Mg.

FIG. 2 shows the control circuit of the above embodiment, where C1 is a capacitor, R+, Rz, Rz, R-.

R, , R, ) Mr. T 1. T! is a transistor, CP, 4m comparator, and comparator C
Transistor T when the output of P1 is at rHJ level.

becomes conductive, and the inverting input terminal of the comparator CP (
-) decreases to some extent, but the potential of the transistor Tt
becomes conductive, the capacitor CI is discharged, and after a certain period of time, the potential of the non-inverting input terminal (+) of the comparator CP1 falls below the potential of the inverting input terminal (-), so the output of the comparator CP becomes the rLJ level. When the output of the comparator CP is at the rLJ level, the transistor TI is cut off and the potential at the inverting input terminal (-) of the comparator CP rises to some extent, but the transistor Tt is also cut off and the capacitor CI is not charged. After a certain period of time, the non-inverting input terminal (+
) becomes higher than the potential of the inverting input terminal, so the output of comparator CP is inverted to rHJ level, and these constitute a pulse oscillation circuit that oscillates a rectangular pulse. SPD is a light receiving element such as a silicon photodiode, OP is an operational amplifier circuit, D is a diode for logarithmic compression, TL is a transistor for logarithmic expansion, C2
is a capacitor for exposure time control, and CPx is a comparator, which together with the trigger switch Ss constitute a well-known exposure time control circuit. T, ~T, are transistors, and when the changeover switch S1 is ON, the transistor Ts is connected via the transistors Tx and Ta.
The electromagnet Mg becomes conductive and the transistor T is cut off via the transistor T.
is now under the control of the pulse oscillation circuit, and when the changeover switch S1 is OFF, the transistor Ts is cut off via the transistors T3 and T4, and the transistor T
When the transistor T becomes conductive through the resistor R, the electromagnet Mg is controlled by the exposure time control circuit with a small current through the resistor R, and together with the changeover switch S, the electromagnet Mg is controlled by the exposure time control circuit. It consists of

Since the electromagnetic shutter according to the present invention is constructed as described above, at the beginning of the purchase of the camera release,
When the power switch is turned on, power is supplied to each part of the circuit, and the pulse generation fi circuit starts operating. At this time, since the changeover switch SI is ON as shown in FIG. 1, the electromagnet Mg is controlled by the pulse oscillation circuit, and the iron piece 10c
As a result, the drive ring 1G repeats left and right rotations, and the closing ring 5 is gradually rotated to the left by the action of the ratchet pawl 12 and the locking pawl lever 14 (so that the closing spring 1 6 is performed (see Fig. 5), and when the closing ring 5 is rotated to the left by the final pulse of the charging stroke and the end 1!5C of the closing ring 5 is pushed to the left, the engagement pin tSC is pushed to the left. As shown in FIG. 3, the locking lever 1B rotates to the left to release the lock from the opening/closing ring 2, and at the same time, the changeover switch Sl is switched to OFF. Then open the Nyatta blade 4 and move N.
The VI stone Mg is now under the control of the exposure time control circuit, and the adsorbed state of the iron piece 10c is maintained.

At this time, the opening/closing ring 4 is subjected to a delay action by the governor 9 via the delay ring 7. Also, at this time, the engagement lever 1
6 is released from the restraint by the upper bent portion 18a, rotates to the left, and engages with the upper bent portion 14a. On the other hand, since the trigger switch S2 is turned OFF by turning the opening/closing ring 2 to the left, the capacitor C1 is charged by the current of the transistor Tt corresponding to the output of the operational amplifier circuit OP (proportional to the intensity of exposure to the light receiving element SPD). Then, when the potential at the lower end of the capacitor Cx becomes lower than the potential at the inverting input terminal (-) of the comparator CP1, the output of the comparator CP is inverted to the rLJ level (see Figure 5).
, Therefore, the transistor T'l is cut off and the electromagnet Mg is demagnetized, so that the drive ring 10 is rotated to the right by the action of the spring 11.

Then, as shown in FIG. 4, the engagement lever 16 moves upward and rotates the locking pawl lever 14 to the left, so that the leading ends of the locking pawl lever 14 and the ratchet pawl 12 are disengaged from the ratchet gear portion 5a. As a result, the closing ring 5 rotates to the right due to the action of the closing spring 6, and its end edge 5b pushes the engagement pin 2b, so that the opening/closing ring 2 resists the tension of the opening spring 3 and is independent of the delay ring 7. The shutter blade m4 is rotated to the right and the shutter blade m4 is closed. At this time, the delay ring 7 slowly rotates to the right due to the action of the return spring 8 and returns to its original position. When the opening/closing ring 2 turns to the right to the end, the locking lever 18 rotates to the right to lock the opening/closing ring 2 again, as shown in FIG. presses the engagement lever 16 and rotates it to the right, so the engagement lever 16 is disengaged from the locking pawl lever 14, and as a result, the locking pawl lever I4 rotates to the right and its tip re-engages with the ratchet pin middle portion 5a, The ratchet pawl 12 also rotates to the right and its tip engages with the ratchet pin middle portion 5a again.

Also, selector switch S and trigger switch S! and returns to the ON state again as shown in FIG.

This completes a series of operations, but since the electromagnetic shutter according to the present invention operates the electromagnet Mg with multiple pulses to charge and release the shutter, the setting force is divided, and as a result, the electromagnet Mg can be downsized. Furthermore, in addition to charging and releasing the shutter using a plurality of pulses, automatic exposure time control is also performed by changing the length of a plurality of pulses, so that all the controls can be performed using Mg electromagnets.

Therefore, the entire shutter can be made more compact. Also, all controls are performed using Mg electromagnets, so
All can be controlled via an electrical interface.

As mentioned above, the electromagnetic shutter according to the present invention has important practical advantages in that it can be made compact and can be controlled entirely through an electrical interface.

[Brief explanation of drawings]

Figure 1 is based on the present invention! A plan view showing the structure of one embodiment of the magnetic shank, FIG. 2 is a diagram showing the control circuit of the above embodiment,
3 and 4 are plan views showing the opening stroke and closing stroke of the shutter blade of the above embodiment, respectively, and FIG. 5 is a waveform diagram of pulses that drive the electromagnet Mg of the above embodiment. l... Board, 2... Opening/closing ring, 3... Opening spring, 4... Shutter blade that also serves as aperture, 5...
Closing ring, 6... Closing spring, 7... Delay ring, 8... Return spring, 9... Governor, 10...
... Drive ring, 11 ... Spring, 12 ... Ratchet pawl, 13 ... Spring, 14 ... Locking pawl lever, 15 ... Spring, 16 ... Engagement lever, 1
7... Spring, 1B... Locking lever, 19...
・Spring, Mg...electromagnet, Sl...changeover switch, Sl...trigger switch.

Claims (1)

[Claims] In an everset type electromagnetic shutter, an electromagnetic drive device is activated by multiple pulses to charge and release the shutter, and automatic exposure seconds are controlled by changing the final pulse length of the multiple pulses. An electromagnetic shutter featuring