JPS636739Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor drive device for a camera.

Recently, there are many electromagnetic release type cameras, and the motor drive devices installed in these types of cameras rotate and operate the motor only when it receives a signal from the camera. Therefore, it was difficult to check the operation of the motor drive device alone. Therefore, even if the motor drive function is lost due to battery exhaustion or malfunction, the motor drive function will not be lost until it is attached to the camera and you actually take pictures. The problem was that I didn't realize what was being said.

For this reason, conventionally, a switch or the like has been operated manually from outside the motor drive device,
There have also been proposals for devices that allow the operation of the motor drive device to be confirmed. One of the techniques that has been used in motor drive devices up until now is a method for automatically stopping the motor when all the exposures have been completed and the next winding is only partway through, by cutting off the power supply to the motor a predetermined time after the motor drive has started.

The above-mentioned time is sufficiently longer than the winding time for normal photography, but is usually set to around 1 second. In a reciprocating winding type motor drive device equipped with such a type of motor stop device, the following problems occur when performing an operation check.

In other words, the operation check can be performed by forcibly operating the winding SW of the motor drive device from the outside, or by installing a new switch in parallel with the winding SW and manually operating this switch from the outside. One possible method is to rotate the motor and check its operation. but,
In these methods, in the case of a motor drive device equipped with a motor stop device as described above, when an operation check is performed, the stop function is activated and the motor is stopped after about one second. The time it takes for the motor to stop is not always constant due to the constants of the time setting circuit and variations in the power supply voltage, and the rotational speed of the motor also changes depending on the power supply voltage, etc., so the winding claw of the motor drive device The winding may stop midway through. If you attach the motor drive device to the camera in this state, the winding claw of the motor drive device and the camera winding shaft will not mesh, so the next time you wind the camera, only the winding claw of the motor drive device will rotate, and the camera will not wind up. You will not be able to do so. Furthermore, since the winding pawl is normally pressed against the winding shaft of the camera by a spring, the winding pawl sometimes stops at the position where winding is completed and does not return to the standby position.

The present invention was devised in view of the above points, and its purpose is to have a self-restoring check switch that can confirm the operation of the motor drive unit alone by manual operation, and to have a self-recovery check switch that can be operated by the check switch. To provide an operation confirmation device for a motor drive device in which a stop device is inactivated while the winding is being carried out, and a hoisting pawl of the motor drive device always returns to a standby position after the check is completed.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

In the figure, M is a motor whose output is used to wind the camera film, and the relay
When the relay RL is energized and its contact is switched to the NO side, power is supplied from the power supply E, and when the relay RL is deenergized and the contact is switched to the NC side, braking is performed due to a short circuit between the terminals. Relay RL is energized by turning on transistor _Q3 and deenergized by turning it off. This transistor Q ₃ is connected to transistors Q ₁ and Q ₂
Of these, the transistor Q ₁ is controlled by the power switch SWo, the camera control switch SWc, and the winding switch SW ₁ linked to the motor M, and the transistor Q ₂
is responsive to a charging/discharging circuit connected to the collector of transistor _Q1 . In this charging/discharging circuit, when the transistor _Q1 is turned on, the capacitor _C1 is charged through the resistor _R5 , and when it is turned off, the capacitor C1 is charged through the diode _D3 and the resistor _{R3 .}
is discharged, and the operator presses the check switch.
Closing SW ₂ causes an instantaneous discharge of capacitor C ₁ via diode D ₂ and switch SW ₂ .

Next, the operation will be explained.

Assuming that the power switch SWo is currently closed, when the control switch SWc is closed due to the end of the camera's photographing operation, current flows through the resistors R ₁ and R ₂ to apply a bias to the transistor Q _{1 and} turn it on. As a result, a base current is applied from the collector of the transistor _Q1 to the transistor _Q3 via the resistor _R8 , turning on the transistor _Q3 , energizing the relay RL, and energizing the motor M.
When the transistor _Q1 turns on, the series circuit of the light emitting diode LED and the resistor _R4 is energized.
When the motor M rotates, the switch _SW1 closes, so even if the camera control switch SWc opens, the transistor _Q1 remains on. winding switch
SW ₁ remains closed until film winding is completed, and during this time transistor Q ₁ remains on.

As a result, base current continues to be applied to transistor Q ₃ , and at the same time, charging current is applied to capacitor C ₁ via resistor R ₅ . The time constant of the charging circuit made up of resistor _R5 and capacitor _C1 is much larger than the time normally required for this motor drive device to complete winding. Therefore, if the winding operation is performed normally, the capacitor
Winding switch SW 1 opens before the charging voltage of C ₁ rises appreciably and therefore _the base of transistor Q ₂ is biased _.
turns off, and the charge in capacitor _C1 is discharged through diode _D3 and resistor _R3 . In other words, if the winding operation is performed normally, transistor Q ₂ will not turn on, and therefore, turning on transistor Q _{2 will turn on transistor Q 2} .
Q ₃ never turns off. Then, the switch _SW1 is opened and the transistor _Q1A is turned off, thereby turning off the transistor _Q3 , deenergizing the relay RL, and stopping the motor M.

On the other hand, if winding switch SW ₁ remains closed for a long time due to reaching the film end, transistor Q ₁ remains on, and charging current is applied to capacitor C ₁ via resistor R ₅ for a long time. It will be done. As a result, the charging voltage of the capacitor _C1 increases and when it reaches a predetermined value, the transistor _Q2 is turned on and the base and emitter of the transistor _Q3 are short-circuited. This turns off transistor _Q3 , deenergizes relay RL, and stops energizing motor M. At this time, the winding pawl of the motor drive device is stopped at a position halfway through winding.

To return the winding pawl, which is stopped in the middle of winding, to the standby position, turn off the power switch SWo.
This turns off the transistor _Q1 , the charge in the capacitor _C1 is discharged through the diode _{D3 and} the resistor _R3 , and the bias of the transistor _Q2 is removed, so the transistor _Q2 turns off.

In this state, take out the film that has already been shot,
When power switch SWo is turned on again, SW ₁ remains on during winding, so the transistor
Q ₁ turns on and transistor Q ₃ turns on again. Therefore, relay RL is energized and motor M
is energized and rotates and stops until the winding switch _SW1 is opened, that is, until the winding standby position is reached.

However, under normal usage conditions, the above operation is performed when the power switch SWo is turned on when a new film is inserted after taking out the film after shooting, so there is no need to perform the above operation every time the film is taken out after shooting is completed. do not have.

Next, a case will be described in which the operation of the motor drive device is checked individually. When the operator turns on the power switch SWo and turns on the check switch _SW2 , current flows through the resistors _R1 , _R2 , and _D1 , and the transistor _Q1
A bias is applied to the transistor Q1, and the transistor _Q1 turns on. This turns on transistor _Q3 , energizing relay RL and energizing the motor.

At the same time, when check switch SW ₂ is turned on, the charging current to capacitor C ₁ that flows through resistor R ₅ flows to check switch SW ₂ through D ₂ , and the voltage of capacitor C ₁ becomes higher than the forward voltage of D ₁ . As a result, transistor _Q2 continues to remain off, so the check switch
The motor will continue to rotate while SW ₂ is on.

Now assume that check switch SW ₂ is turned off in the middle of winding due to its self-restoring property. Since the winding is in progress, the winding switch _SW1 is on and the motor continues to rotate. Charging current also flows into the capacitor _C1 via the resistor _R5 , but the motor has completed winding by the time it reaches the voltage level that turns on the transistor _Q2 , and the winding switch _SW1
Turn off. As a result, transistor _Q1 is turned off, transistor _Q3 is also turned off, relay RL is deenergized, the motor is stopped, and the winding pawl is stopped at the standby position.

In addition, if the check switch SW ₂ is operated while the camera is taking pictures, the motor will rotate and move the film, or vibrations of the motor will interfere with normal shooting. When installed, it is desirable to place it in a position where it cannot be operated or to make it inoperable.

As mentioned above, the present invention can be applied to the motor drive device of a reciprocating winding camera equipped with a time-controlled stop device by providing a self-restoring check switch for checking the operation as described above. Functions such as the presence or absence of a battery and the presence or absence of a malfunction can be confirmed, and since the winding claw always returns to the standby position before the motor stops, it is possible to prevent mistakes when attaching the camera to the camera.

[Brief explanation of drawings]

The figure is a circuit diagram showing an embodiment of the present invention. Q...transistor, D...diode,
LED...Light emitting diode, C...Capacitor,
R...Resistance, RL...Relay, M...Motor,
SWo...power switch, SWc...camera control switch, SW ₁ ...winding switch, SW ₂ ...check switch.

Claims (1)

[Scope of Claim for Utility Model Registration] A motor drive device that starts a motor for driving a winding pawl by a control switch of a camera, and then continues to supply electricity to the motor via the winding switch until winding is completed, the motor drive device comprising: a resistor; In a motor drive device for a reciprocating wind-up camera, the motor drive device has a time constant circuit consisting of a capacitor and a capacitor, and a device that measures the energization time to the motor and stops the energization to the motor when the energization time reaches a predetermined value. , has a self-restoring check switch that is operated manually and energizes the motor, and the operation of the check switch short-circuits both ends of the capacitor of the time constant circuit to shorten the time of the stop device. The motor is continued to be energized so as to stop the measurement operation, and when the check switch becomes inactive, the short circuit between both ends of the capacitor of the time constant circuit is released, and the time measurement operation is started in the stop circuit. A motor drive device for a camera, characterized in that the motor is stopped after the winding claw is returned to a standby position by energizing the motor and returning the winding claw to a standby position.