JPH0627331U - Shutter-control device for surveillance camera - Google Patents

Abstract

(57) [Abstract] [Purpose] In the vehicle-mounted rear monitoring camera 17, when the camera 17 does not operate normally, the driver is notified of the abnormality of the camera 17 without opening the protective shutter. [Structure] A sync separation circuit 27 for extracting a sync signal from a video signal output from a surveillance camera 17, and a sync separation circuit 2
The operation detection circuit 31 that outputs a start signal while the synchronization signal is being input from 7 and the shutter drive motor 59 that is normally rotated when the start signal is input, and the shutter drive motor 59 that is rotated when the input of the start signal is stopped. A shutter drive motor starting circuit 41 for reversing the rotation and a switch circuit 61 for activating an alarm device 71 when a start signal is not input when the power supply to the surveillance camera 17 is turned on are provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an on-vehicle surveillance camera, and more particularly to a shutter opening / closing control device provided on the front surface of a protective case of the surveillance camera.

[0002]

[Prior art]

 Nowadays, in order to confirm the rear of vehicles such as buses and trucks, a small surveillance camera such as a CCD camera for rear surveillance is attached to the rear of the vehicle, and a monitor TV is often installed in the driver's seat. The surveillance camera mounted on the rear of the vehicle is covered with a protective case to protect the camera from rain and dust, and a shutter as an opening / closing door is installed in front of the lens of the surveillance camera to move the vehicle backwards. This shutter is opened when necessary when operating the surveillance camera, and normally this shutter is kept closed to prevent the camera and camera lens from becoming dirty.

The shutter opening / closing control mechanism normally detects that the gear lever has been moved to the reverse position, rotates the shutter drive motor, and causes the timer to operate the shutter only for the time required for opening / closing the shutter. Open / close control is performed while applying a voltage to the drive motor (for example, actual opening No. 2-66342), detecting the opening / closing position of the shutter by a sliding contact or limit switch that detects the opening / closing position of the shutter (for example, actual opening). No. 62-117881), which automatically closes the shutter when the gear lever is removed from the reverse position.

[0004]

[Problems to be solved by the device]

 As described above, in the device that automatically opens the shutter by moving the gear lever to the reverse position, when the gear lever is set to the reverse position, if the rear of the vehicle is not displayed on the monitor TV in the driver's seat, the driver However, it was not possible to immediately judge whether the surveillance camera itself was defective or the shutter or shutter opening / closing mechanism was defective.

Further, even if the surveillance camera is out of order, the shutter is opened by putting the gear in the back, and passers-by and workers in the rear of the vehicle are supposed to have the driver confirming himself / herself on the monitor TV. The illusion is that it is easy to be alert to the reverse movement of the vehicle, and accidents may occur more easily.

[0006]

[Means for Solving the Problems]

 The present invention provides an operation detection circuit that extracts a synchronization signal from the video signal of the surveillance camera that operates when the gear lever enters the reverse position by the synchronization separation circuit, and outputs a start signal while the synchronization signal is being input. A switch circuit is provided that activates the alarm device when the start signal from the operation detection circuit is not input by inputting the same power supply as that of the surveillance camera, and the start signal from the synchronization detection circuit is used to start the shutter drive motor. Input to the circuit to open and close the shutter.

[0007]

[Work]

 According to the present invention, the sync separation circuit extracts the sync signal from the video signal of the surveillance camera to form the start signal.Therefore, when the surveillance camera does not operate normally, the start signal is not output and the switch circuit is made conductive. It is possible to keep the shutter closed by notifying the abnormality of the camera by the alarm and without activating the shutter drive motor starting circuit.

[0008]

【Example】

 As shown in FIG. 1, the shutter control device according to the present invention includes a first input terminal 21 connected to a power supply terminal of a surveillance camera 17, and a second input terminal 23 to which a video signal from the surveillance camera 17 is input. The power supply terminal of the alarm device 71, the control input terminal of the switch circuit 61 and the power supply terminal of the sync separation circuit 27 are connected to the first input terminal 21, and the signal input terminal of the sync separation circuit 27 is connected to the coupling capacitor 25. Via the second input terminal 23, the output terminal of the sync separation circuit 27 is connected to the operation detection circuit 31, and the output terminal of the operation detection circuit 31 is connected to the other control input terminal of the switch circuit 61 and the shutter drive motor. It is connected to the starting circuit 41.

As shown in FIG. 2, the power supply terminal of the surveillance camera 17 and the power supply terminal of the monitor TV 19 are connected to the battery 11 via the back gear detection switch 15 and the main switch 13, and the shutter drive motor is also connected. The starting circuit 41 appropriately switches the voltage polarity from the battery 11 and applies the battery voltage to the shutter drive motor 59.

Therefore, in this shutter control device 20, when the back gear detection switch 15 is turned on by moving the gear lever to the reverse position while the main switch 13 is turned on, the surveillance camera 17 is turned on. The operation is started, the power supply voltage is applied to the alarm device 71, and the sync separation circuit 27 is also started. When the video signal from the surveillance camera 17 is input, the sync separation circuit 27 extracts only a pulse-shaped sync signal from the video signal and sends it to the operation detection circuit 31.

The operation detection circuit 31 to which the synchronization signal is input is configured by, for example, an integration hold circuit 33 and a Schmitt circuit 37, and a pulsed synchronization signal is input to the integration hold circuit 33 and the integration hold circuit 33. When the output level of the Schmitt circuit 37 reaches the threshold value of the Schmitt circuit 37, the Schmitt circuit 37 outputs an L level start signal, and when the input of the synchronizing signal to the integration hold circuit 33 is stopped, the Schmitt circuit 37 outputs the output signal. Is returned to the H level and the output of the start signal is stopped.

The switch circuit 61 to which the start signal is input is composed of an AND circuit 63, a switching transistor 65, and an appropriate limiting resistor, and one input terminal of the AND circuit 63 is connected to the first input terminal. To the input terminal 21, another input terminal is connected to the output terminal of the Schmitt circuit 37, the output terminal of the AND circuit 63 is connected to the base of the switching transistor 65 via a resistor, and the switching transistor 65 is connected. Is for grounding the emitter and connecting the collector to the alarm 71.

Therefore, when a voltage is input to the AND circuit 63 from the first input terminal 21, the switch circuit 61 makes the switching transistor 65 conductive unless the start signal from the operation detection circuit 31 is input, and outputs an alarm. The device 71 is caused to generate an alarm sound. The shutter drive motor starting circuit 41 is composed of an inverter, a pulse generator, a relay switch and a holding circuit, and a shutter rotation position detecting switch, as shown in FIG. 3, and the Schmitt circuit in the operation detecting circuit 31. The output terminal of 37 is connected to the first pulse generator 43 via the inverter 42, the output terminal of the Schmitt circuit 37 is directly connected to the second pulse generator 44, and the output terminal of the first pulse generator 43 is connected to the first pulse generator 43. The output terminal of the second pulse generator 44 is connected to the control terminal of the first relay switch 45, and the common terminal of the first relay switch 45 is the shutter position detection switch 51. The common terminal of the second relay switch 46 is connected to one input terminal of the drive motor 59 and the other input end of the shutter drive motor 59. Connected to, B terminal of the first relay switch 45 and the second relay switch 4 6 respectively grounded, each A terminal is for connecting each through the holding circuits 47 and 48 to the power supply bus Tteri 11.

As shown in FIG. 4, the shutter position detection switch 51 has an insulating portion 57 formed on the surface of a disk conductor that rotates in accordance with the rotation of the shutter, and three contact points are brought into contact with each other. As shown in A of 4, the first contact 52 is in contact with the insulating portion 57 and the second contact 53 and the third contact 54 are short-circuited in the open position of the shutter. 4B, all of the first contact 52 to the third contact 54 are short-circuited to each other, and in the closed position of the shutter, the second contact 53 contacts the insulating portion 57 as shown in C of FIG. The first contact 52 and the third contact 54 are short-circuited.

Therefore, when an L-level start signal is input to the shutter drive motor starting circuit 41, the first pulse generator 43 via the inverter 42 outputs a pulse signal and the common terminal of the first relay switch 45. Is connected to the A terminal, and the shutter position detection switch 51 causes the drive motor 59 to rotate normally because the first contact 52 and the third contact 54 are short-circuited as shown in C of FIG. The first relay switch 45 keeps the shutter drive motor 59 rotating even after the pulse signal from the first pulse generator 43 is cut off by the holding circuit 47, and when the shutter reaches the open position, it is indicated by A in FIG. As described above, the first contact 52 of the shutter position detection switch 51 contacts the insulating portion 57 to stop the rotation of the motor, and the common terminal of the first relay switch 45 is the B terminal. Returned to the connection to the child.

When the input of the start signal from the operation detection circuit is stopped, the second pulse generator 44 outputs a pulse signal to connect the common terminal of the second relay switch 46 to the A terminal, When the shutter drive motor 59 is rotated in the reverse direction so that the shutter is in the completely closed position and the second contact 52 of the shutter position detection switch 51 comes into contact with the insulating portion 57 as shown in C of FIG. 4, the rotation of the motor is stopped. The connection of the common terminal in the second relay switch 46 is returned to the B terminal.

As described above, in the shutter control device 20 according to the present embodiment, the back lever detection switch 15 is turned on by putting the gear lever in the reverse position, the monitoring camera 17 operates, and the monitoring camera 17 outputs the video signal. Then, the sync separation circuit 27 extracts the sync signal from the video signal, the operation detection circuit 31 outputs an L level start signal, and the shutter drive motor starter circuit 41 rotates the shutter drive motor 59 in the forward direction to open the shutter. The AND circuit 63 of the switch circuit 61 is closed by the level start signal and the alarm device 71 is not activated. Even though the back gear detection switch 15 is turned on, a video signal is output from the surveillance camera 17. If not, the output of the operation detection circuit 31 is maintained at H level, The AND circuit 63 in the switch circuit 61 sets the output to the H level in combination with the power supply voltage applied to the surveillance camera 17, and turns on the switching transistor 65 that is in series with the alarm device 71 to cause an alarm from the alarm device 71. A sound is emitted, and the shutter drive motor starting circuit 41 keeps the shutter closed without operating.

In the above embodiment, the operation detection circuit 31 outputs the L level start signal, but even when the operation detection circuit 31 outputs the H level start signal, the switch circuit 61 and the shutter drive motor starter circuit 41 can be operated in the same manner by incorporating an inverter into the shutter drive motor starter circuit 41 and performing level inversion. Further, the shutter drive motor starter circuit 41 is operated by a timer and a forward / reverse changeover switch circuit. It is also possible to output the forward rotation signal to the motor for a fixed time after the input of, and output the reverse rotation signal to the motor for a fixed time after the start signal is stopped.

As shown in FIG. 5, the switch circuit 61 has a delay circuit 69 of about 0.5 seconds to several seconds inserted between the AND circuit 63 and the first input terminal 21 so that the surveillance camera 17 can operate. In the case of a camera of a type that requires some time from power-on to video signal output, the alarm device 71 may be erroneously prevented from operating. The alarm device 71 is not limited to a sounding type such as a buzzer, but the alarm lamp can be made to blink.

Further, the power supply for operating the inverter 42, the AND circuit 63, and the Schmitt circuit 37 is supplied by being directly connected to the battery or by being connected to the battery 11 via the main switch 13. The power source terminal of the alarm 71 is not only connected to the first input terminal 21, but is directly connected to the main switch 13 or in the shutter drive motor starting circuit in series with the switch circuit 61. It is also possible to connect directly to the battery 11 together with 41.

[0021]

[Effect of device]

 Since the shutter control device of the surveillance camera according to the present invention extracts the synchronizing signal from the video signal and controls the shutter drive motor, when the surveillance camera fails, the shutter is not opened and the person behind the vehicle is monitored. There is no illusion that the camera is working.

Further, when the video signal including the normal synchronizing signal is not output from the surveillance camera, the switch circuit is brought into the conductive state to activate the alarm device, so that the driver can be clearly notified of the camera failure.

[Brief description of drawings]

FIG. 1 is a block diagram of a shutter control device for a surveillance camera according to the present invention.

FIG. 2 is a diagram showing a circuit example of a surveillance camera using a shutter control device according to the present invention.

FIG. 3 is a diagram showing an example of a shutter drive motor starting circuit.

FIG. 4 is a diagram showing a contact example of a shutter position detection switch.

FIG. 5 is a diagram showing another embodiment of the switch circuit.

[Explanation of symbols]

11 Battery 15 Back Gear Detection Switch 17 Surveillance Camera 19 Monitor TV 20 Shutter Control Device 21 First Input Terminal 23 Second Input Terminal 27 Sync Separation Circuit 31 Actuation Detection Circuit 41 Shutter Drive Motor Starting Circuit 59 Shutter Drive Motor 61 Switch Circuit 71 Alarm Device

Claims (1)

[Scope of utility model registration request] 1. A first device connected to a power supply terminal of a surveillance camera
It has an input terminal and a second input terminal to which a video signal from the surveillance camera is input, and is connected to the second input terminal and is connected to a sync separation circuit for extracting a sync signal from the video signal and to the sync separation circuit. The operation detection circuit that outputs a start signal while the synchronization signal from the sync separation circuit is being input, and a forward rotation signal to the shutter drive motor at the start of output of the start signal that is connected to the operation detection circuit and a start signal. A shutter drive motor starting circuit that outputs a reverse rotation signal to the shutter drive motor at the end of output, and a switch that is connected to the first input terminal and the operation detection circuit and conducts when a start signal is not input when power is supplied to the surveillance camera. And a switch circuit, the switch circuit being connected in series with an alarm device connected to a power source. The control device.