JPS5934894Y2 - Camera tuning contact circuit - Google Patents

Description

[Detailed explanation of the invention] This invention consists of a camera tuning contact circuit, specifically a direct hot shoe dedicated to the X contact, a synchro socket, and an X contact circuit.
The present invention relates to a tuning contact circuit for a camera having a -FP contact changeover switch, particularly a -eye reflex camera.

Conventionally, in high-end cameras such as -eye reflex cameras,
Built-in tuning contact circuit with a direct hot shoe dedicated to the X contact, a synchro socket, and an X-FP contact switching switch so that it can be used with both an FP class tuned light bulb and a strobe device that is a flash synchronized light emitter. has been done.

As is well known, the direct hot shoe mentioned above has an electrical contact for connecting an electric circuit inside the accessory shoe of the camera, and when a strobe device with a corresponding electrical contact is attached, the strobe device automatically connects to the hot shoe. The X contact inside the camera is connected cordlessly to the electric circuit inside the camera.

Next, before explaining the present invention, an example of the conventional tuning contact circuit will be explained with reference to FIG.

In the same figure, electrical contact 1 of direct hot shoe 1
a is connected to the internal connection terminal 2a of the synchro socket 2, and the external connection terminal 2b of the socket 2 and the shoe fitting 1b of the hot shoe 1 are each body grounded.

The connection point between the electrical contact 1a and the connection terminal 2a is X-
Switching movable contact terminal Sea of FP contact switching switch S1
is connected to one fixed terminal S of the switch S1.
1b is connected to the fixed terminal of the X timing switch S2, the other fixed terminal S1c is connected to the fixed terminal of the FP timing switch S3, and both switches S2. S
Each movable contact piece terminal No. 3 is grounded.

When using a strobe device that does not have an electrical contact connected to the electrical contact 1a of the hot shoe 1 or a light emitting device of an FP class luminous bulb, the synchro socket 2 is used to insert the synchro plug into the strobe device. Alternatively, it serves to connect the X timing switch S2 or the FP timing switch S3 in the camera to the electric circuit in the light emitter via the changeover switch S1.

In addition, in a single-lens reflex camera having a focal plane shutter, the X timing switch S2 is
It is turned on when the shutter is fully opened when the leading curtain ends, and turned off when the trailing curtain ends or in connection with film winding.

The FP timing switch S3 is turned on before the front curtain travels, for example, 10 m5 before the front curtain travels, and operates so that the amount of light emitted from the FP luminescent bulb reaches its maximum when the shutter is fully opened.

In the conventional tuning contact circuit that is bottomed out in this way,
When using a strobe device that has electrical contacts that correspond to hot shoe 1, attach the strobe device to hot shoe 1, and replace switching switch S1 with X timing switch S.
When the shutter button is pressed after switching to 2, the X timing switch S2 is turned on when the shutter is fully open, and synchronized flash light emission is performed.

In addition, when using a strobe device that does not have an electrical contact corresponding to the hot shoe 1 or an FP light emitter, insert the synchro plug into the synchro socket 2 and turn the switch S1. All you have to do is to switch the X timing switch S2 to the alligator, and for the FP bulb light emitter, to the FP timing switch S3, and then press the shutter button.

Then, the X timing switch S2 or the FP timing switch S3 is turned on, and synchronized light emission is performed when the shutter is fully open.

The above is an example of a conventional tuning contact circuit.
1 to the optimum state, complete synchronized light emission cannot be obtained.

That is, in the case of a strobe device that uses the hot shoe 1, if the FP timing switch S3 is switched to the wrong side by erroneously operating the changeover switch S1, the strobe device will flash before the shutter is fully opened. When using an FP bulb light emitting device, if the X timing switch S2 is switched to the wrong side by erroneously operating the changeover switch S1, the FP bulb will start emitting light when the shutter is fully opened, making it impossible to obtain synchronized light emission. This results in an underexposed photo.

On the other hand, in the tuning contact circuit at the bottom of the tank as described above, since the synchro socket 2 and the electrical contact 1a of the hot shoe 1 are always connected, the synchro socket 2
When the synchro plug of the strobe device is inserted into the strobe device, the relatively high charging voltage of the trigger capacitor in the strobe device is also applied to the electrical contact 1a.

Therefore, without attaching a strobe device to hot shoe 1,
When a strobe device is attached using a camera's tripod hole or the like, there is a risk of electric shock if the photographer accidentally touches the electrical contact 1a.

Therefore, as a measure to prevent electric shock, a diode is inserted in the connection between the electrical contact 1a of the hot shoe 1 and the synchro socket 2 (Utility Model Publication No. 52-15225, Utility Model Application No. 4).
No. 9-21039 and Japanese Utility Model Application Publication No. 49-137535) have already been proposed.

However, in this conventional electric shock prevention device, the anode of the diode is connected to the electrical contact 1a of the hot shoe 1, and the cathode is connected to the synchro socket 2, so that a positive voltage is applied to the electrical contact 1a, and a negative voltage is applied to the shoe fitting 1b. It is effective for devices in which a negative voltage is applied to the electrical contact 1a and a positive voltage is applied to the shoe fitting 1b, as seen in some foreign-made strobe devices. has no effect.

By the way, recent strobe devices are designed to have an electrical contact connected to the electrical contact 1a, based on the fact that most of the camera accessory shoes are direct hot shoes. .

An object of the present invention is to provide a tuning contact circuit for a camera that overcomes the above-mentioned conventional drawbacks by paying attention to these points.

Hereinafter, the present invention will be explained based on the illustrated embodiment.

FIG. 2 is a camera tuning contact circuit showing an embodiment of the present invention.

In this proposal, the X-FP contact changeover switch is configured with a 1-circuit 2-contact changeover switch S7 without using a diode or the like,
It skillfully eliminates the drawbacks of the previous model.

In FIG. 2, the electric contact 4a of the direct hot shoe 4 is connected to one X fixed terminal S7c of a changeover switch S7 configured with one circuit and two contacts.

Then, the other FP fixed terminal S7 of this switch S7
b is connected to ground, and the switching movable contact terminal S7a of the switch S7 is connected to the FP timing switch S6.
Connected to the movable contact terminal.

The fixed terminal of this switch S6 is connected to the internal connection terminal 5a of the synchro socket 5, and the external connection terminal 5a of the socket 5 is grounded.

The FP timing switch S6 is turned on when the movable reflector of the -eye reflex camera moves upward.

Further, the electric contact 4a is connected to a fixed terminal of an X timing switch S5, and a movable contact terminal of the switch S5 is connected to ground.

In the above-described embodiment configured in this manner, when using a strobe device having electrical contacts, the strobe device is attached to the hot shoe 4, and the switch S7 is connected to the X fixed terminal S7.
Simply switch to c and press the shutter button.

When the shutter is pressed, the movable reflector rises and closes the FP timing switch S6, but since the synchro socket 5 is not used, this closing is an operation unrelated to light emission.

Then, when the shutter is fully open, the X timing switch S
5 is closed, a trigger current flows from the electrical contact 4a to the ground through the switch S5, and the strobe device emits flash synchronized light.

In the present invention, even if the selector switch S7 is accidentally switched to the FP fixed terminal S7b while the strobe device is in use, the switching mode of the switch S7 and the FP
Regardless of the operation of the timing switch S6, when the X timing switch S5 is closed, a trigger current flows from the electrical contact 4a to the X timing switch S5 to perform flash synchronized light emission.

Therefore, the conventional drawbacks can be overcome.

Furthermore, in the case of a strobe device that does not have electrical contacts, a synchro plug may be inserted into the synchro socket 5, and the switch S7 may be switched to the X fixed terminal S7c.

In this way, the FP timing switch S6 is closed by the bounce of the movable reflector, and the X timing switch S5 is closed when the shutter is fully opened, so that the trigger current is transferred to the movable contact terminals S7a and X of the FP timing switch S6 and the switch S7. Since the current flows through the fixed terminal S7c and the X timing switch S5, synchronized flash light emission is performed.

When using the FP bulb light emitter, it is sufficient to insert a synchro plug into the synchro socket 5 and switch the switch S7 to the FP fixed terminal S7b.

Then, as the movable reflector rises, the FP timing switch S6 closes, and the trigger current flows to the movable contact terminal S7 of the FP timing switch S6 and the switch S7.
a, flows to the FP fixed terminal S7b to perform synchronized light emission.

According to the present invention, the electrical contact 4 of the hot shoe 4
When using a strobe device that has an electrical contact that comes into contact with a, even if the X-FP contact changeover switch S7 is accidentally switched to the FP fixed terminal S7b, the strobe device will still emit flash synchronized light completely. So, the drawbacks of this kind of conventional products are eliminated.

Further, according to the present invention, the FP timing switch S6, which is closed when the movable reflector jumps up, is connected between the synchro socket 5 and the switching movable contact terminal of the X-FP contact switching switch, and Since the connection between the shoe's electrical contact and the synchronizer socket is open, the charging pressure of the trigger capacitor will not be applied to the hot shoe's electrical contact through the synchro socket.
This completely prevents electric shock.

Furthermore, when the FP timing switch S6 is turned on, the charging pressure of the trigger capacitor is applied to the electric contact 4a, but at this time, the camera is being photographed and the camera is normally held with both hands. In this state, no fingers or the like touch the hot shoe, and electric shock is completely prevented.

In addition, this electric shock prevention means does not use a diode as in conventional methods, so it is carried out regardless of the directionality of the diode. Even in a strobe device to which a voltage is applied, electric shock can be effectively prevented by switching the X-FP contact changeover switch to the X fixed terminal.

Furthermore, when a strobe device is attached to the direct hot shoe and a data imprinting device is connected to the synchro socket, even if the strobe device fires a test light, the FP timing switch is in the OFF state, so the data imprinting device does not work. Since no activation signal is applied and the device does not work, double copying of data can be completely prevented.

As described above, according to the present invention, it is possible to provide a camera tuning contact circuit which eliminates the conventional drawbacks, has a simple circuit configuration, has fewer failures, and is highly practical.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing an example of a conventional camera tuning contact circuit, and FIG. 2 is an electric circuit diagram of a camera tuning contact circuit showing an embodiment of the present invention. 1.4... Direct hot shoe, 2,5.
...Synchro socket, Sl, S7...
X-FP contact changeover switch, S2. S5...
X timing switch, S3. S6...FP timing switch.

Claims (1)

[Claim for Utility Model Registration] A shoe fitting for attaching a strobe device is grounded to the body of the camera, and a dedicated A direct hot shoe, an X-timing switch whose one end is connected to the above-mentioned electrical contact of the direct hot shoe, and whose other end is grounded to the body and is closed when the shutter is fully opened, and whose external connection terminal is grounded to the body. It consists of a synchro socket with an FP timing switch connected to its internal connection terminal, and a selector switch.When the synchro socket is used as an X contact, its switching movable contact terminal connects to the direct hot shoe's electrical An X-FP contact in which the X fixed terminal connected to the contact can be switched to the FP contact, and when the synchro socket is used as an FP contact, the movable contact terminal can be switched to the FP fixed terminal connected to the body ground. A changeover switch and
This X-FP contact changeover switch has one end connected to the switching movable contact terminal and the other end connected to the internal connection terminal of the synchro socket, and is an FP timing switch that is closed before the shutter is fully opened. A camera tuning contact circuit comprising: