JPH0535885Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an anti-theft device for a car stereo that is detachable from the front of the driver's seat of a passenger car.

<Conventional technology> Conventional car stereo theft prevention devices require that the car stereo be detachably attached to a dash board installed in front of the driver's seat, the engine key of the passenger car inserted, and the switch of the car stereo turned "ON". The release pin can be inserted only when the car stereo is grounded and the car stereo can be removed from the dash board. For example, Akira Jitsugane
There is No. 62-117456.

<Problems to be solved by the invention> However, in the conventional example described above, if you leave the car with the engine key inserted, the car radio can be operated freely even if it is turned off, making it susceptible to theft. There is a risk. Therefore, the present invention deals with the drawbacks of the above-mentioned conventional example,
Furthermore, the present invention aims to provide a device that is highly effective in preventing theft.

<Means for solving the problem> A hanging plate is provided on the side of the car stereo cabinet and is adapted to be attached to and removed from the dash board, and a hole is provided on the cabinet front plate corresponding to the front end of the hanging plate. An electromagnetic shielding plate is interposed between the release pin and the through hole to prevent insertion of the release pin by a timed operation when the engine key of the passenger car is turned on.

<Function> Insertion of the release pin is prohibited even if the driver removes the engine key, and even if the engine key is inserted and the engine is in the "ON" state, the release pin is not inserted after a certain time limit has been reached. This works to prevent the car stereo from leaving the car.

<Example> The present invention will be explained in detail below using the example shown in the drawings.
It is similar to No. 117456 and is shown in FIGS. 1 to 3.

That is, as shown in FIGS. 1a and 1b, through holes 2, 2, .
Notches 5, 5 are provided in the inner side plates 3, 3 of 2..., respectively, and the notches 5, 5 are provided on the outside of the notches of the side plates 3, 3, as shown in Fig. 1a.
Or, as shown in Figure 1b, latches 7',
Two tongue pieces 7, 7 with bent portions 7' form the notches 5,
An electromagnet 11, which is operated by an anti-theft circuit 18 to be described later, is set on a support plate 17 which is mounted so as to be bent inward through the front plate 1 and parallel to the front plate 1. Core 1 of the electromagnet 11
The other side 14 of the bending part of the electromagnetic shielding plate 13 is fixed to the tip of the support plate 17 , and a sliding support piece 15 is bent and connected at a right angle to the other side 14 of the bending part.
It is slidably held by pins 16 erected above.

On the other hand, the side plate 10 adjacent to the stereo cabinet of the dash board 8, which is adapted to accept the insertion of the car stereo, is designed to engage with the latches 7', 7' of the latch plate 6 when the cabinet is inserted. A notch 9 is provided so that when the cabinet is inserted into the holding portion of the dash board 8, the front end surfaces of the latches 7', 7' of the latch plate 6 engage with the front edge of the notch 9.

The anti-theft circuit for operating the electromagnet 11 is constructed as shown in FIG.

That is, the collector-emitter terminal of the switching transistor _Q1 is connected between the terminal T that is linked to the key and GND via the delay capacitor _C2 , and the base of the transistor _Q1 is connected between the terminal T and GND. Connected to the junction of voltage dividing resistors R ₁ and R ₂ connected via delay capacitor C ₁ to
Furthermore, a discharge resistor _R3 is connected to the junction between the delay capacitor _C2 and the collector terminal of the switching transformer _Q1 .
The base of another switching transistor _Q2 is connected through the
The emitter side of Q ₂ is connected to the terminal T, and the collector terminal side of the transistor Q ₂ is connected to the base terminal of the switching transistor Q ₃ , which is connected between the nolenoid co-oil L connected to the terminal T and GND. It is connected via a bias resistor _R4 .

Next, to explain these series of operations, when the driver removes the engine key and leaves the driver's seat, the circuit of terminal T opens in conjunction with this, and the circuit of terminal T is opened, The power supply to the anti-theft circuit 18 is stopped.

Therefore, each switching transistor Q ₁ , Q ₂ ,
Since no power is supplied to all the anti-theft circuits including Q ₃ and solenoid L, naturally solenoid coil L does not operate and shielding plate 13
A state in which the core 12 is pushed to the left as shown in Figure 1a by a compression spring wrapped around its outer periphery (arrows are unrelated)
, and closes the inside of the through hole 2 to release the release pin 1.
9 is prevented from being inserted, and the release of the latched state of the latches 7', 7', . . . is prohibited.

Then, when the engine key is turned on, the delay capacitor is connected to the terminal T connected to it.
_C1 is charged through resistors _R1 and _R2 , and the base voltage is applied during that time, so the switching transistor
Q ₁ is in the "ON" state, and together with this, a charging current also flows through the delay capacitor C ₂ , and during this time, the base voltage is also applied to the transistor Q ₂ via the discharging resistor R ₃ , and the transistor
Keep Q ₂ "ON", and when the capacitor C ₂ is saturated, the discharge current I will increase as shown by the broken line.
now flows through transistor Q ₂ ,
During this time, the collector-emitter of the transistor Q ₂ is maintained in the "ON" state, and a base voltage is applied to the switching transistor Q ₃ to energize the solenoid coil L, energizing the electromagnet 11, and causing the core 12 to resist the spring. and move it to the right [in the direction of the arrow in FIG. Guided by the bent portion 4, the tongues can easily enter between the latches 7', 7' of the tongues 7, 7, as shown in FIG. 2b, thereby causing the tongues to move to the right. As the latches 7' and 7' are pushed and bent, they are also moved to the right and are released from the front edge of the notch 9, allowing the car stereo A to be taken out from the dash board. Then, during the operation of the electromagnet 11 mentioned above, that is, the time when the transistor Q ₃ is in a conductive state, the delay capacitor C ₁ is charged, and during the short period while the capacitor C ₂ is also charging, and then being discharged. Only when the blocking operation by the shielding plate 13 is released is executed.

In other words, the release pin can only be accepted within a certain period of time after inserting the engine key and turning it on, and if you forget to remove the engine key and leave the driver's seat temporarily with the engine key still inserted. Even in this case, after a certain period of time has elapsed, the circuit leading to the solenoid L of the electromagnet 11 is automatically cut off, and the shielding plate 13 is closed.

In other words, the timed operation starts based on the point when the engine key is inserted and the engine key is turned "ON", and the time during which the release pin can be inserted is determined. Even in this state, insertion of the release pin is excluded after a certain period of time has passed.

<Effects of the invention> Since the present invention is constructed as described above, when the engine key is removed, the power to the anti-theft circuit is naturally cut off, so the electromagnet does not operate and the shield plate remains closed. condition, it is impossible to remove the car stereo from the dash board without accepting the release pin. In addition, even if you insert the engine key and leave the seat in the "ON" state, the switching transistors Q ₁ and Q ₂ of the anti-theft circuit 18 will be activated after a certain period of time from the time the engine key is inserted. The circuit of the electromagnet 11 is cut off for a limited time (several tens of seconds) determined based on the capacitance of the delay capacitors C ₁ and C ₂ and the resistors R ₁ and R ₂ , and the shielding plate remains open until then. This prevents the driver from closing the door and inserting the release pin, making it impossible to remove the car stereo, so the driver cannot turn on the engine key.
It is possible to completely prevent theft even if you temporarily leave your car unattended.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the device of the present invention, FIG. 1a is an enlarged side view of the main parts of the mechanism, FIG. 1b is an enlarged side view showing the operating state of the same, and FIG. 3 is a partially cutaway perspective view of the car stereo, and FIG. 4 is a theft prevention circuit diagram. 1...Front plate, 2...Through hole, 3...Side plate, 5...
... Notch, 6 ... Latching plate, 7 ... Tongue piece, 8 ... Dash board, 9 ... Side wall, 10 ... Electromagnet, 1
2...Core, 13...Shielding plate, 18...Anti-theft circuit, _C1 , _C2 ...Capacitor, _R1 , _R2 ...Resistor, _Q1 , _Q2 , _Q3 ...Transistor, L... ...Solenoid coil.

Claims (1)

[Scope of utility model registration request] The car stereo is fixed by inserting the car stereo into the dart board from the front and engaging the hooking plate on the car stereo with the hooking part of the dash board, and the hooking plate and the hooking part are fixed. In a device in which the release operation is performed mechanically by a release pin inserted through a hole in the front panel of the car stereo, the release pin appears between the hole in the front panel of the car stereo and the latch plate and the latch part. a shielding plate that is freely provided and always positioned between the through hole and the locking plate and the locking part by the elasticity of a spring to prevent insertion of the release pin from the through hole; and a shielding plate that is energized. When an electromagnetic means is moved backward against the spring to release the insertion prevention operation of the release pin, and when an engine key is inserted, power is supplied to the electromagnetic means, and a certain period of time has elapsed after the insertion of the engine key. A theft prevention device for a car stereo, comprising: a time limit control means for automatically cutting off power supply to the electromagnetic means when the electromagnetic means is stopped.