JPH0591151U - External power supply - Google Patents

Abstract

(57) [Abstract] [Purpose] When an external power supply device is connected to a portable device such as a camera and the portable device is used by the power supply device, at least the external power supply device generates heat even if the external power supply device generates heat. And to protect the portable device. An external power supply device comprising a battery used as an external power source for a portable device, a battery storage chamber for storing the battery, and an electric circuit for supplying power to the portable device by the battery, A temperature detecting element is provided in the battery storage chamber, and a cutoff unit for cutting off a current flow of the electric circuit when the detected temperature of the temperature detecting element rises is provided in the external power supply device.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an external power supply device connected to a portable device such as a camera.

[0002]

[Prior Art]

 Conventionally, a battery has been used as an internal power source of a portable device such as a camera. For example, in a camera, a standard type is one in which an AA battery is incorporated. In this way, the standard type may have a problem that the number of shots is relatively small due to the small amount of electric charge, and instead of the internal power source of the portable device described above, an external power supply device connected to the device may be used. As such, an external power supply device including a battery such as a single battery and an electric circuit for supplying power to the above-mentioned portable device by the battery is used.

However, when a short circuit occurs at the output terminal of the external power supply device due to mischief or the like to the output terminal, a large current exceeding the maximum rated current value of the external power supply device causes an electric circuit of the power supply device. There is a risk that the battery and the electric circuit of the power supply device generate heat due to the flow, and the battery and the electric circuit are damaged. If the input terminal is short-circuited due to mischief or the like before connecting the output terminal to the input terminal of the portable device, the maximum rated current of the external power supply device will be exceeded as described above. A large current exceeding the value will flow into the electric circuit of the power supply unit, and the flow of heat will cause the battery or electric circuit of the power supply unit to heat up, resulting in the risk of damage to the battery or electric circuit. ..

Furthermore, if a wiring failure occurs in the electric circuit provided inside the portable device for some reason, a short circuit (circuit short circuit) may occur in the electric circuit. At that time, the above-mentioned large currents flow into the electric circuits of the external power supply device and the portable device, respectively, which causes the battery of the external power supply device and the electric circuits of the power supply device and the portable device to generate heat. Then, each electric circuit and the battery are damaged.

A maximum rated current value is predetermined for the external power supply device, and when the maximum rated current value is exceeded, the current is referred to as a large current. A large current flows through the electric circuit of the device, and each electric circuit and the battery of the external power supply device generate heat and there is a risk of damage. Furthermore, even if the motor provided inside the camera receives the output current from the external power supply and tries to rotate, it cannot rotate, for example, the number of frames taken by the film is far exceeded. Even if it exceeds the limit, when the winding motor tries to wind the film for some reason, if the end of the film is locked to the rotating shaft inside the patrone, even if the winding motor tries to rotate, Due to the above-mentioned locking via the film, an abnormal state may occur in which the winding motor cannot be rotated while it is still on.In this case, the current from the external power supply device is passed through the inside of the camera. As a result, a state close to a short circuit occurs, in which the current flows through the coil of the hoisting motor. Due to this state, the large current described above may flow into the electric circuits of the external power supply device and the portable device. Due to this flow, similarly to the above, the electric current of the respective electric circuits and the external power supply device may be increased. The battery heats up and is damaged.

In order to prevent these dangers, conventionally, a protection circuit such as a circuit breaker or a fuse is provided in the external power supply device, and the protection circuit allows the electrical circuit of the portable device or the electric power of the external power supply device to be protected. Protects circuits and batteries. The above-mentioned protection circuit operates by detecting a large current exceeding a maximum rated current value of the external power supply device when the large current flows into the electric circuit of the power supply device.

[0007]

[Problems to be solved by the device]

 However, when the above-mentioned large current does not flow, for example, when the voltage of the battery provided in the external power supply device drops for a long time, the output terminal of the external power supply device short-circuits and to some extent. When the output terminal of the external power supply device is short-circuited due to the one having the resistance value of, a current slightly smaller than the above-mentioned maximum rated current value flows into the electric circuit of the external power supply device. Although the current is slightly smaller than the maximum rated current value as described above, if the current flows into the electric circuit of the external power supply device for a long time, the above-mentioned protection circuit will not operate. , The electric circuit or battery of the external power supply unit will generate heat, which may cause the electric circuit or battery to be damaged.

Therefore, in view of the above problems, the present invention allows not only the above-mentioned large current but also a current slightly smaller than the maximum rated current value of the external power supply device to flow into the electric circuit of the external power supply device. However, it is an object of the present invention to prevent the electric circuit of the power supply device and the electric circuit of the portable device from being damaged, and also prevent the battery provided in the external power supply device from being damaged.

[0009]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a battery used as an external power source of a portable device, a battery storage chamber for storing the battery, and a battery for supplying power to the portable device. In an external power supply device including an electric circuit, a temperature detecting element disposed in the battery storage chamber, and when the temperature detected by the temperature detecting element rises, the current flow of the electric circuit is cut off. It was equipped with a shutoff means.

[0010]

[Action]

 If, due to the above-mentioned short circuit, a current that is slightly smaller than the maximum rated current value of the external power supply unit flows in the electric circuit of the external power supply unit for a long time, or if the above-mentioned large current flows in the electric circuit, the Since the above-mentioned battery connected to the circuit generates heat and the battery is stored in the battery storage chamber as described above, the above-mentioned temperature detecting element arranged in the battery storage chamber is Detects the temperature rise in the battery compartment due to heat generation. By this detection, the above-mentioned interruption means interrupts the flow of current to the electric circuit of the external power supply device, and the current slightly smaller than the maximum rated current value or the above-mentioned large current is interrupted by the above interruption. As a result, the electric power does not flow to the electric circuit of the external power supply device or the electric circuit of the portable device described above, and therefore the electric circuit of the external power supply device and the portable device or the battery of the external power supply device are not damaged. Can be protected.

[0011]

【Example】

 FIG. 1 is a schematic perspective view showing an example of a camera system in which an external power supply device 1 according to the present invention can be connected to a camera 2. In FIG. 1, a camera 2 is equipped with a taking lens 3, and a subject image obtained by the lens 3 can be visually recognized by a finder 4. The power source of the camera 2 may be an AA battery, which is an internal power source (not shown), or the external power source device 1.

The external power supply device 1 is connected to the cord 20, and when the connector 6 of the cord 20 is inserted into the connector receiving portion 5 of the camera 2, the camera 2 has an AA battery therein. The external power supply device 1 is electrically connected to the camera 2 by being disconnected from the electric circuit in the camera. The box-shaped external power supply device 1 has a plurality of AA batteries 8 housed in the battery housing chamber 19, and the AA batteries 8 can be replaced by opening the lid 7. The springs 21a and 21b on the inside of the lid 7 are terminals that come into contact with the electrodes of the AA battery 8 with the lid 7 closed, and are designed to press the AA battery 8 in the battery storage chamber 19. is there.

FIG. 2 is a circuit diagram showing an electric circuit of each of the external power supply device 1 and the camera 2 according to the present invention. As shown in the figure, the electric circuit surrounded by the block 1 on the left side is the electric circuit provided inside the external power supply device 1 in FIG. 1, and the electric circuit surrounded by the block 2 on the right side is the camera 2 described above. The electric circuit provided in the inside of is shown. As shown in the block 2, the electric circuit in the camera 2 includes an exposure control circuit 9 for controlling the exposure of the camera and a display circuit for displaying the data in the camera such as the shutter speed and the aperture value. 10 and a drive circuit 11 for driving a motor for autofocus, film feeding, etc. The electric circuit of the external power supply device 1 is used as a power source as shown inside the block 1. A plurality of single cells 8, an air circuit breaker 14 that also serves as a temperature detecting element and a shut-off means described later, a regulator 12 used as a constant voltage power supply circuit, and an overcurrent detection resistor 13. Is becoming

As is well known, the connector 6 of the cord 20 of the external power supply device 1 has a hollow cylindrical portion and a concentric cylindrical portion located in the hollow, respectively, and has a terminal for receiving the connector of the camera 2. The portion 5 has respective terminals consisting of a first hollow cylindrical portion and a second hollow cylindrical portion located in the hollow, and the connector 6 of the cord 20 is inserted into the connector receiving portion 5 of the camera 2. Then, the connection terminals 5a and 6a in FIG. 2 corresponding to the hollow cylindrical portion of the connector 6 and the first hollow cylindrical portion of the connector receiving portion 5 are connected to each other, and the concentric cylindrical portion of the connector 6 and the connector receiving portion are connected. The connection terminals 5b and 6b in FIG. 2 corresponding to the second hollow cylindrical portion of the portion 5 are also connected to each other. By this connection, the electric circuit in the block 1 is used as a circuit for supplying power to the electric circuit of the camera 2.

The overcurrent detection resistor 13 located inside the block 1 is for converting the current flowing from the battery 8 into a voltage, and the regulator 12 has an overcurrent limiting circuit provided therein. There is. The overcurrent limiting circuit limits the current when the maximum rated current value of the external power supply device is exceeded, that is, when the voltage value by the above-mentioned resistor 13 exceeds a predetermined value, The overcurrent limiting circuit limits the current under the control of the regulator 12 itself.

As described above, when the output terminal of the external power supply device is short-circuited or the internal short circuit of the camera occurs, the voltage value becomes equal to or higher than the predetermined value due to the above-mentioned resistor 13, and the regulator detects it. 12 controls itself, and the internal overcurrent limiting circuit limits the current, but since it limits when the maximum rating is exceeded, there is no change in that a large current (large current) flows.

Further, if the overcurrent limiting circuit does not operate for some reason, a very large current larger than that when the above-mentioned limiting is performed flows, and in order to prevent the flow of these large currents, Causes an absolute circuit break to be performed by the air circuit breaker 14 in FIG. Details are as follows. Even if a current slightly smaller than the maximum rated current value flows in the electric circuit of the external power supply device 1 for a long time due to the above-mentioned short circuit or the like, the above-mentioned large current still causes the electric circuit of the external power supply device 1. Even if it flows to the inside, the A-size battery 8 generates heat due to its internal resistance, and due to the heat generation, the room temperature of the battery storage chamber 19 in FIG. 1 rises. The air circuit breaker 14 detects this temperature rise and shuts off the circuit by itself, and the air circuit breaker 14 may be a breaker, a thermostat, or the like as long as it can shut off the circuit by sensing the temperature.

FIG. 3 shows a thermostat used as the air circuit breaker 14. The cylindrical temperature detecting portion 15 located on the right side in the figure is provided with two sections 22 and 23 therein, and although not shown in the figure, one of the two is provided via the main body 14a. The contact piece 22 is connected to the terminal 17, and the other contact piece 23 is connected to the terminal 18. The above-mentioned contact piece 23 is formed of a bimetal in which two kinds of metals having different coefficients of thermal expansion are stuck together, and together with the one piece 22 constitutes one kind of switch which is curved by temperature.

At a normal low temperature, the sections 22 and 23 are in contact with each other, and this contact causes a short circuit between the terminals 17 and 18. When the ambient temperature rises, the segment 23 bends due to the bimetallic structure and separates from the one contact piece 22, and this separation causes the terminals 17 and 18 to be opened and the air circuit breaker 14 in FIG. Is also converted to the open (off) state. Due to this conversion, the current flow of the electric circuit in the block 1 is cut off, so that a current slightly smaller than the maximum rated current value or the large current described above flows in all the circuits in FIG. It is possible to prevent all the circuits and the battery 8 from being damaged. Therefore, the thermostat 14 of FIG. 3 is also used as the temperature detecting element and the above-mentioned shut-off means. The screw hole 16 in FIG. 3 is for fixing the thermostat 14 with a screw (not shown).

FIG. 4 is a schematic perspective view showing the battery storage chamber 19 of the external power supply device 1, which is a posture when the external power supply device 1 is actually used, such as a strap (not shown). When it is hung on the photographer's shoulder, the state shown in the figure is assumed. The battery storage chamber 19 is designed so that three AA batteries 8 are vertically arranged in two rows and a total of six batteries can be accommodated between the rows so that these batteries can be properly accommodated in the battery storage chamber 19. A partition 24 is provided. Springs 25 and 26 are attached as electrodes under the battery storage chamber 19 in the figure. The thermostat 14 is installed above the partition 24 in the figure. This is because when the internal air of the battery storage chamber 19 is warmed by the heat generated by the AA battery 8 and convection occurs, the interior of the battery storage chamber 19 is closed. The heat is concentrated in the upper part of the figure, so it was installed at this location. It should be noted that as long as the rise in the room temperature of the battery storage chamber 19 can be detected by the heat generation of the single battery 8, it is not necessary to install the partition 24 above the drawing, and it may be installed anywhere.

FIG. 5 is an enlarged view of the thermostat 14 in FIG. 4 and a part of the periphery of its installation position. The thermostat 14 is screwed through the screw holes 16 in FIG. It is fixed to the partition 24 by 27. In order to detect the rise in the room temperature of the battery storage chamber 19 due to the heat generation of the single battery 8, the temperature detecting portion 15 of the thermostat 14 is attached so as to be exposed from the cutout portion of the partition 24 shown in FIG. There is. This is to ensure that the air in the room warmed by the heat generated by the AA battery 8 efficiently strikes the temperature detecting portion 15 of the thermostat 14.

Although the cutout portion is provided in FIG. 5, any method may be used as long as it is a method capable of reliably detecting an increase in the room temperature, for example, by providing a ventilation hole and mounting it inside the ventilation hole. There is no. Although not shown in FIGS. 4 and 5, the overcurrent detection resistor 13 and the regulator 12 in FIG. 2 are provided inside the partition 24 in FIG. The terminal 17 is connected to the terminal 25 in FIG. 4 through a connection cord (not shown) provided inside the partition 24, and the other terminal 18 in FIG. It is connected to the detection resistor 13. The other end of the regulator 12 connected to the resistor 13 is connected to the central cylindrical portion (connection terminal 6a) located in the connector 6 of the cord 20, and the other terminal 26 in FIG. Is connected to the concentric cylindrical portion (connection terminal 6b) formed on the connector 6 of the cord 20. The terminals 21a and 21b located inside the lid 7 in FIG. 1 are electrically connected by connecting pieces (not shown).

FIG. 6 is a schematic perspective view showing an embodiment in which two thermostats 14 are provided in the battery storage chamber 19 of the external power supply device 1. As shown in this figure, a thermostat 14 is provided above one inner wall of the battery storage chamber 19, and another thermostat 14 is provided below one end of the diagonal line passing through that portion, that is, below the other inner wall. There is. The circuit at this time is to insert another air circuit breaker 14 between the battery 8 and the air circuit breaker 14 shown in FIG. 2 so that two air circuit breakers are connected in series. Except for the two air circuit breakers 14, the same as described above.

When the aforementioned single cell 8 generates heat, at least one of the two air circuit breakers 14 detects an increase in the indoor temperature, and the contact piece 23 in FIG. In order to cut off the flow of current away from the piece 22, regardless of the posture of the external power supply device 1, a current slightly smaller than the maximum rated current value or the above-mentioned large current is generated. Therefore, the electric circuit and the battery 8 can be prevented from being damaged.

According to the above-mentioned embodiment, the temperature detecting element is also used as the blocking means as described above, but as another embodiment, it may be provided separately. At this time, in the air in FIG. Instead of the circuit breaker 14, a movable switch is provided, and the movable switch and a control unit for controlling the opening / closing of the circuit breaker constitute the above-mentioned breaking means. It is also possible to install the temperature sensor inside the wall, instead of the thermostat 14 shown in FIG. 3, and to operate as follows.

In advance, the movable switch is turned on by the above-mentioned control unit, and when the battery 8 generates heat due to the above-mentioned short circuit or the like, the room temperature of the battery storage chamber rises and the above-mentioned temperature detection sensor is used. The control unit opens (turns off) the movable switch, and by this opening, the current slightly smaller than the maximum rated current value and the large current described above do not flow, and the electric circuit described above is released. It goes without saying that you can protect

Further, as described above, the camera is used as the portable device and the dry battery of the single battery is used as the external power source. However, the present invention is not limited to the above-described embodiment, and the external battery may be a storage battery such as a storage battery. Use a battery for cars, etc. and a portable device such as a video camera that can be operated by the battery.In this case, install a battery compartment for accommodating the battery and the battery compartment. An external power supply device provided with the temperature detection element, an electric circuit for supplying power to the above-mentioned equipment by a battery, and the above-mentioned shut-off means may be provided and operated as follows.

When a short circuit occurs in at least one of the portable device such as a video camera and the above external power supply device for some reason, if the above battery heats up, the battery is installed in the battery storage chamber of the battery storage. In addition, the above-mentioned temperature detection element detects an increase in the room temperature of the battery storage chamber, and the above-mentioned shut-off means shuts off the flow of current in the internal circuit of the external power supply device. Similarly, a current that is slightly smaller than the maximum rated current value of the external power supply device or the large current described above does not flow into the electric circuit of the external power supply device or the portable device, and the electric circuit or the battery is damaged. Can be prevented.

Further, although the protection circuit such as the circuit breaker and the fuse described above is not provided in FIG. 2, as another embodiment, the electric circuit in the block 1 in FIG. 2 is provided with the protection circuit described above. Alternatively, when the above-mentioned large current flows, the protection circuit cuts off the large current flow, or the air circuit breaker 14 cuts off the large current flow due to the heat generation of the battery, Alternatively, if a current slightly smaller than the maximum rated current value flows for a long time, the air circuit breaker 14 interrupts the current flow due to the heat generation of the battery, as described above. There is no hindrance to the purpose of.

[0030]

[Effect of the device]

 As described above, according to the present invention, even if the external power supply is in any posture due to the above-mentioned short circuit, the temperature of the battery in the external power supply is increased by the heat generated by the battery itself of the external power supply. And for that purpose the aforementioned interrupting means can cause the electrical circuit of the external power supply device to interrupt its current flow. By this interruption, the electric circuit of the portable device, the electric circuit of the external power supply device, and the battery can be protected.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a camera system according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing circuits arranged inside the external power supply device 1 and the camera 2 of FIG.

FIG. 3 is a schematic perspective view of a thermostat used as an example of a temperature detecting element.

FIG. 4 is a schematic perspective view of an external power supply device according to an embodiment of the present invention.

5 is an enlarged perspective view showing the temperature detecting element 14 and its surroundings in FIG.

FIG. 6 is a schematic perspective view of an external power supply device when two temperature detecting elements 14 are provided in a battery storage chamber 19 according to another embodiment of the present invention.

[Explanation of symbols]

1 ... External power supply device, 2 ... Camera, 8 ...
・ Single battery 14 ・ ・ ・ Temperature detection element, 19 ・ ・ ・ Battery storage chamber

Claims (5)

[Scope of utility model registration request] 1. An external power source including a battery used as an external power source for a portable device, a battery storage chamber for storing the battery, and an electric circuit for supplying power to the portable device by the battery. In the device, a temperature detecting element disposed in the battery storage chamber, and a shutoff means for shutting off the current flow of the electric circuit when the temperature detected by the temperature sensing element rises are provided. Characteristic external power supply. 2. The external power supply device according to claim 1, wherein the temperature detecting element is installed in a place where heat is concentrated in the battery storage chamber. 3. The external power supply device according to claim 1, wherein a plurality of temperature detecting elements are installed at both ends of the battery storage chamber that are diagonal to each other. 4. The external power supply device according to claim 1, wherein a temperature detecting portion of the temperature detecting element is exposed inside the battery storage chamber. 5. The external power supply device according to claim 1, wherein the temperature detecting element is also used as the shutoff means.