JPS589220Y2 - Camera electric winder drive circuit - Google Patents

Description

[Detailed explanation of the invention] With this invention, the shutter is activated by the release operation during shooting, and when the shutter shooting operation is completed, the shutter is turned on.
It can be attached to a camera body equipped with a switch mechanism that turns it off when the film has finished winding.
This invention relates to a drive circuit for an electric winder in which film can be automatically wound by an electric motor 1.

Conventionally, in an electric winder, a clutch mechanism provided between a film winding shaft and a film winding motor has been used as means for detecting the completion of film winding.

In this type of device, when the film winding is completed, the rotation of the film advance shaft stops, but the motor tries to continue rotating, so an overload is applied and the clutch is disengaged. .

For this reason, some devices operate an overload switch connected to the clutch mechanism, turning off the motor drive circuit and stopping the rotation of the motor.

However, such devices have the disadvantage that they cannot distinguish between the completion of presentation and the end of the film.

Therefore, it has been proposed to provide a timer circuit, for example, as a film end detection means, and to detect the end of the film based on the operation of the timer circuit.

As for how to operate this timer, since the normal film winding time is about 0.5 seconds, the timer is set to operate at, for example, 0.7 seconds.

When the rear curtain of the shutter completes its travel and a signal is sent from the camera body to command the next film advance, the timer starts operating, and when the film advance is completed, the film is Since the presentation completion signal is sent, the timer is reset by this signal.

In this way, during normal winding, the timer is reset approximately 0.5 seconds after the timer starts operating, so the timer does not issue an output signal.

However, when the film ends, the film winding completion signal is not sent even after about 0.5 seconds after the timer starts operating, so the timer is not reset and the initially set time, e.g. 0.7 seconds, elapses. Then, it outputs an output signal and can detect the end of the film.

Further, at this time, it is also possible to indicate the end of the film by the output signal of the timer.

However, in such conventional devices, even if the winding shaft stops rotating when the film is finished, the motor is not energized for a while (maximum of 0.7 seconds in the previous example). Due to the continuous operation, a large current flows through the motor and there is a risk of burning out the motor coil, relay contacts, etc., which limits the types of batteries that can be used, and has the disadvantage of increasing battery consumption. .

In order to improve these conventional drawbacks, the present invention provides a new electric winder drive circuit that uses a winding command switch inside the camera body and an overload switch on the winder side, and improves the winder operating mechanism. It is simple, improves operability, and eliminates all restrictions on use.

In addition, it is possible to switch between frame photography and snapshot photography, making it easy to perform continuous shooting, and making it possible to use various types of batteries. It is designed to enable display and reduce battery consumption.

Next, an embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a circuit diagram showing an embodiment of the invention, in which E is a power source such as a battery, M is a motor for film winding, RL is a relay, Tr2 is a transistor, C1 is a capacitor for starting, and D 1 is a diode for backflow prevention, D2 is a diode for suppressing the back electromotive force of the relay, R1-R6 are resistors, So is a power switch, and SL is a single or multi-switch switch for switching between frame-by-frame shooting and continuous shooting. , S2 is a release interlocking switch, which is always on and remains off only while the camera release button is pressed.

S3 is a winding command switch, which is a camera shutter that operates when the camera shutter is activated and the shooting operation is completed; for example, in the case of a focal plane shutter, it turns on when the trailing curtain completes travel, and turns off when the film has finished advancing. This is a switch installed inside.

S4 is an overload switch, which is always on and turns off when it detects that the motor f is overloaded (this is the switch on the winder side).

SL is a switching type contact of the relay RL, and the movable contact C is normally connected to the fixed contact a side, and only when the relay RL is energized, the fixed contact side is switched.

Power switch S. When not using the winder, or when replacing the film with a new one after the film is finished, always connect contacts C and A. Capacitor C1 is always f
This is the state f in which the charges are discharged.

The operation of this embodiment composed of the components as described above will be explained in order below.

In the state shown in Fig. 1, the hoisting command switch S3 is on and the relay RL is not operating, so the switching contact SL is connected between contacts c and a, and the overload switch S4 is On state, transistor Tr1,
Tr2 is in the off state, and the single/multi changeover switch S1 is set to the M side, that is, the multi shooting side (from this switched state, the power switch S is turned off).

When the winder circuit f is operated to the left and the contact points c and c are connected from the state shown in the figure, the voltage is supplied to the winder circuit f.

At this time, the discharge circuit of the capacitor C1 is opened, so that the capacitor C1 starts charging via the emitter and base of the transistor T r 1.

At this time, a charging current flows to the capacitor C1 (therefore, the transistor Tr1 is turned on, so the transistor Tr
Current flows through the collector of transistor T r 2, turning on transistor T r 2.

After a certain period of time, the capacitor C1 completes charging and stops passing the charging current, but when the transistor Tr2 is turned on, the emitter of the transistor Tr1 → the base → the resistor R4 →
Since current flows through the path from diode D1 to collector to emitter of transistor Tr2, transistor Trl
, Tr2f together form a self-holding circuit.

Therefore, relay RL operates and maintains its operation.

When relay RL operates, its switching contact SL switches to contacts c and b.
This can be switched to connect between

Therefore, the motor M is started and winds the film.

When the film is finished being played, the winding command switch S3 is turned off, so that the relay RL is turned off.

For this reason, the switching contact SL of the relay RL is switched so that the contacts c and a are connected (as this is done, the energization to the motor M is stopped, and the motor M is braked and stopped.

Therefore, overload switch S4 will not turn off, so
Even in this state, the transistor Tr1. Tr2 continues to maintain the on state.

At this time, if the camera's shirt release button is continued to be pressed, a photographing operation will be performed after the film winding is completed, and the shutter will be activated.

When the shutter shooting operation is completed, the display command switch S3 is turned on again, so the relay RL operates again and the contact c and b of the switching contact SL are connected, so the motor M is connected to the power supply E. Once connected, it starts up and winds the film.

When the film presentation is completed, the presentation command switch S3 is turned on again.
is turned off, relay RL is turned off and motor M is stopped.

In this way, as long as the shutter release button is kept pressed, the operations described above are repeated to perform continuous shooting.

Next, to explain in detail when performing single photography, first, prior to photography, the single/multi selector switch S1 is switched to the S side, that is, to the single photography side.

Then, starting from the initial state where film winding is completed, the power switch S is turned on.

However, when contacts c and a are connected as shown in Figure 1, the winding command switch S3 is off and the release interlocking switch S2 is on, as explained earlier. The situation is the same as for continuous shooting.

Now power switch S. From the state shown in the diagram, rub f so that the contacts and c are connected, and as explained above, f
At this time, the transistors Tr1tTr2 are turned on to form a self-holding circuit.

However, since hoisting command switch S3 is off, relay R
L does not work.

When the release button is pressed in this state, photographing starts and the release interlock switch S2 is turned off.

Thereafter, when the rear curtain of the shutter finishes running, the winding command switch S3 is turned on, but since the release interlocking switch S2 is turned off, the relay RL does not operate.

Subsequently, when the release button is released, the release interlock switch S2 is turned on, and as a result, from the power source E, the single/multi selector switch S1 → the release interlock switch S2 → the winding command switch S3 → the relay RL → the transistor Tr2. Between the collector and emitter of → power supply switch′
A current flows through the path So→power source f, operating the relay RL, and connecting the contacts c and b of the switching contact SL.

As a result, the motor M is started and the film is played.

When the film is finished playing, the winding command switch S3 is turned off, so the relay RL is turned off and the switching contact S is turned off.
Contacts c and b of L are opened, power to motor M is cut off, and the motor stops.

Next, when the release button is pressed again, the operation as described above is performed, and each time the release button is pressed, the film is automatically played.

Next, when the film ends, the film winding shaft stops rotating during the film winding operation, so the motor f becomes overloaded.

When this state is detected by the overload switch 84f, the overload switch S4 is turned off.

Therefore, the transistor T r 1 is turned off, and thereby the transistor Tr2 is also turned off, so that the relay RL does not operate.

Therefore, contacts c and b of switching contact SL of relay RL are opened, and power to motor M is immediately cut off.

Fig. 2 shows an embodiment in which a circuit for displaying the finished state of the film in the electric winder as shown in Fig. 1 is added. DP is added.

During normal photographing operation (in this case, embodiment f in Fig. 1 above)
As shown, since the transistor Tr1 is always on, the transistor Tr2 is also always on.

Therefore, the transistor Tr3 is on and Tr4 is off, so the light emitting diode LED does not light up.

However, when the film ends, as explained above,
Since the transistor Tr2 is turned off, the transistor T
r3 is turned off and transistor Tr4 is turned on.

Therefore, the light emitting diode LED lights up to indicate that the film has finished.

This display operation lets you know that the film has finished, so first press the power switch S.

Operate F so that contacts C and A are connected as shown in the figure, discharge capacitor C1, replace the film, and prepare for the next photographing operation.

In the embodiment described above, two
We explained the case where transistors are used.
It is not limited to transistors, but can also be replaced with elements that have a self-holding function, such as cyrisks and relays.
The display means is not limited to a light emitting diode, and other display means including, for example, an acoustic generator can also be used.

As explained above, in some cases, the advance command switch inside the camera body and the overload switch on the winder side are used in combination, and when the film is advanced (in this case, at the same time as winding is completed, the film is At the end of the process, the power to the motor can be cut off and the motor can be stopped immediately, which prevents accidents such as excessive current flowing through one motor and causing it to burn out, and also prevents relay contacts from being overloaded. This prevents excessive current from flowing, and accidents such as contact burnout can be prevented.

In addition, a circuit to indicate the end of the film can be easily added, and the overall winder configuration can be simplified.
It has many advantages such as good operability and not being subject to various restrictions.

[Brief explanation of drawings]

Figure 1 is a circuit diagram showing an example of the inconvenience, and Figure 2 is a circuit diagram showing an example of the inconvenience.
FIG. 2 is a circuit diagram of an embodiment in which a display circuit is added to the embodiment shown in the figure. M...Film winding motor, RL...Relay, S
L... Relay switching contact, C1... Capacitor, D
l. D2...Diode, Trl, Tr2...Transistor, So...Power switch, Sl...Single
Multi-selection switch, S2... release interlocking switch, S3... performance command switch, S4... overload switch, LED... light emitting diode.

Claims (1)

[Scope of utility model registration request] A single/multiple selector switch that switches between single-frame shooting and continuous shooting, a winding command switch that is turned on when the shutter shooting operation is completed, and turned off when the film advance is completed, and a relay are connected in series, and the series circuit f here is connected in series. A circuit in which a switching element is connected in series, a series circuit consisting of a film winding motor and a normally open contact of the relay are connected in parallel, and the circuit is connected between both terminals of the power supply via a power switch.・Connect a normally closed release interlocking switch that turns off only when the release button is pressed between the single side contact and the multi side contact of the multi-switch switch. A camera comprising a self-holding circuit that includes a normally closed overload switch that is only turned off, and that turns on the switching element when the power switch is turned on and maintains that state until the overload switch is turned off. electric winder drive circuit.