JPS61238546A - Steal preventing device for vehicle - Google Patents

Abstract

PURPOSE:To prevent a tire, etc. from being stolen, by surely detecting the rise-up of a vehicle upon stealing a tire, and by issuing an alarm. CONSTITUTION:A closed container 1 is formed by inner and outer peripheral walls 11, 12 each of which is curved in a downward convex shape in the center section thereof and which is in a circular shape in a plan view. A closed container 1 is held on a base plate 51 secured to a vehicle floor, etc. and contains therein a liquid 2 having an amount which is less than the volume of the container 1. An upper electrode 3 and lower electrodes 41, 42 are attached to the upper and lower surfaces of the container 1 so that they are opposed to each other with the liquid 2 being held therebetween. These electrodes 3, 41, 42 constitute a capacitor. Further, an inclination detecting means 7 detects the capacitance of the capacitor which varies when the liquid is displaced in association with the inclination of the vehicle during parking thereof, and energizes an alraming device (not shown) through a cord 58 when the capacitance of the capacitor varies exceeding a predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a theft prevention device for a vehicle, and more particularly to a theft prevention device that is effective in preventing tire theft.

[Prior Art] Conventionally, vehicle theft prevention devices have been known to prevent vehicle theft by locking the steering wheel, but this is ineffective against tire thieves [and vehicle theft using tow trucks]. There is no.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle theft prevention device that can prevent the tire theft and the like by reliably detecting lifting of the vehicle during theft and issuing an alarm.

Means for Solving Problem 1] The anti-theft device of the present invention has a sealed container 1 (FIG. 1). The container 1 has a circular plane and is surrounded by an inner circumferential wall 11 and an outer circumferential wall 12 whose central portion is curved downward in a convex shape.

The sealed container 1 is held on a substrate 51 fixed to a vehicle floor or the like, and a liquid 2 smaller than the volume of the container 1 is sealed inside the container 1. On the upper and lower surfaces of the container 1, an upper electrode 3 and a lower electrode 41, 42 are arranged to face each other with the liquid 2 interposed therebetween, and the electrode 3 and the electrode 4L42 form an electrode J. Inclination detection means 7 (31
The capacitance of the capacitor, which changes due to the tilt of the parked vehicle (and the accompanying movement of the liquid 2), is detected, and an alarm signal is issued when the capacitance changes by a predetermined value or more.

[Effect of the invention 1: The vehicle in the movie was lifted up and tilted by a jack or a tow truck.
When it soaks, the liquid 2 in the container 1 moves and the capacitance between each electrode 3.71L4.2 changes,
An alarm will be issued. This prevents tire theft and the like.

Furthermore, if the present invention is used between stations, the capacitance will change even if the vehicle is tilted in any direction, ensuring that the vehicle is stolen! 11
It is possible to detect and notify.

[Example] FIG. 1 shows an overall sectional view of the anti-theft device.

In the figure, the device housing consists of a board 51 fixed to the floor of a vehicle trunk room, etc., and a rectangular cylindrical cover plate 52 covered with this, and a sealed container 1 inside the housing.
The container 1 is circular (Fig. 2), and the center part is curved downward in a convex shape.In other words, the container 1 has a resin inner circumferential wall formed into a bowl shape. 11 and an outer circumferential wall 12 are separated by a predetermined distance and fitted liquid-tightly at their outer peripheries, and a dielectric liquid 2 smaller than the volume of the container 1 is sealed inside the container 1.

A hemispherical upper electrode 3 is provided along the upper surface of the sealed container 1, and the electrode 3 is screwed to a rectangular support plate 53 disposed above it at the center of the upper surface. It is electrically connected to the formed lead portion. A cylindrical center electrode 41 with a concave upper surface is provided along the center of the lower surface of the container 1, and a peripheral electrode 41 is provided concentrically with the electrode 41 along the outer periphery of the lower surface of the container 1. We have set up 42. The electrodes 41 and 42 are screwed to a support plate 54 disposed in contact with the lower surfaces thereof, and are formed on the support plate 54 or are electrically connected in a single portion. The outer peripheries of the container 1 and the peripheral electrode 42 are covered with a cylindrical shield case 55.

The tilt sensor constituted by the sealed container 1 and the electrodes 3, 41, 42 has four corners of the support plate 53, 54.
It is fixed to the substrate 51 with screws 5G that pass through it. The screw 5G has an inclined center marked -h by the spacer 57.
A printed board 61, 62 on which a tilt detection circuit 7 is formed is held and held at a predetermined interval, and the electrodes 3, 41, 42 are connected to the tilt detection circuit 7. The alarm signal issued by the tilt detection circuit 7 is
Coat bushing 5 provided on the outer periphery of the lower J4j of the cover plate 52
It is taken out of the device by a lead wire (not shown) passed through the inside of the device.

Due to the dielectric liquid 2 sealed in the container 1, a capacitance C1 is generated between the upper electrode 3 and the center electrode 41, and a capacitance C2 is generated between the upper electrode 3 and the peripheral electrode 42.

When the vehicle tilts and the dielectric liquid 2 moves, the capacitance C
1 and C7 change, and by detecting the difference between these capacitances @C1 and C2, the tilt angle can be detected no matter which direction the vehicle tilts.

The tilt detection circuit 7 is shown in FIG. 30 is an oscillation circuit, which is an RC oscillation circuit formed by connecting Invar 1 to Goo 1 in series. Then, from the oscillation circuit 30 to the invert gate 301
Pulse signals of opposite phases are applied to the center electrode 41 and the peripheral electrode 42 through invert gates 302 and 303, respectively.

” - so that the capacitance C1 between the lightning 4 and the center electrode 41 and the capacitance C2 between the upper electrode 3 and the peripheral electrode 42 are equal when the vehicle is horizontal. the above electrode 3;
/'12 in parallel with ]ndenza C3. Therefore, when the vehicle is horizontal, pulse voltage signals 3081 and 11 are generated at the upper electrode 3, and as the inclination angle of the vehicle increases, the voltage width of the pulse voltage signal 30a increases.

This pulse voltage signal 30a enters the amplifier circuit 31, is amplified by the operational amplifier 311, and is connected to the operational amplifier 321, resistor 322, 323, diode 324, and capacitor 32.
Smoothing is performed by a smoothing circuit 32 configured by 5. The output voltage of this smoothing circuit 32 becomes lower as the inclination angle of the vehicle becomes larger, that is, as the pulse voltage signal 30a becomes larger. The above outputs are provided by analog switches (Toshiba C4066) 331a, 331b,]]tin'J-332a332b and operational amplifiers 333a, 3.
The analog switches 331a and 331 are manually inputted to the lean pull hold circuit 33 as a two-system memory circuit configured by 33b, and then the analog switches 331a and 331 are
(b closed)] A voltage corresponding to the inclination of the vehicle is held in the detectors 332a and 332b.

The comparators 341a and 341b of the comparator circuit 34 compare the voltages of the operational amplifiers 333a and 333b, and when a difference of more than a certain value occurs, that is, when the vehicle tilts, the output reaches the 11 OIT level.

35 (J, time limit circuit, divider counter 35L352 (
Toshiba TC4020>, decimal counter 353a, 35
3b (TC4017 made by Toshiba) and Goo 1~, outputs a signal to close the analog switches 331a, 331t) to the sample hold circuit 33 at fixed time intervals, and outputs a latch signal to the alarm circuit 37 described later. do.

The alarm circuit 37 is composed of a D-type flip-flop 371, a frequency division counter 372, a transistor 373, and a gate, and the output of the comparison circuit 34 described in OI
When the frequency reaches the T level, the frequency division counter 372 starts frequency division,
1 to transistor 373 operate and issue an alarm signal. A horn or the like is blown by the alarm signal.

The periodic voltage generation circuit 38 supplies voltage to each of the operational amplifiers and comparators at regular intervals to reduce current consumption. 39 is necessary for a constant voltage circuit. 40 is a reset circuit.

The operation of the anti-theft device having the above structure will be explained below.

When a switch (not shown) is turned on when the vehicle is parked, the constant voltage circuit 3
The power supply VB is supplied to the reset circuit 40, and the timer circuit 35 and alarm circuit 37 are reset. Then, the transmission signal from the transmission circuit 30 is inputted to the time limit circuit 35, and the terminal Q1, terminal Q2, terminal Q
5. The signals (a) to (d) shown in FIG. 4 are output to the terminal Q6. The R terminals of the decimal counters 353a and 353b receive signals 1e), (f) (FIG. 4) which are the logic of the reset 1 signal from the reset circuit 40 and the terminals Q5 and Q6 of the frequency dividing counter 352. is input. Therefore, signals 1) and (h) (FIG. 4) are output to the output terminals 01 of the counters 353a and 353b, respectively. And AN
r) Signals (i), (, j) (Fig. 4) are output to the outputs of 354 to goo 1 and 355 to OR goo 1.

Signal (i) is a latch signal. The signal (, j) is input to a periodic signal generating circuit 38, which supplies an operating voltage to each operational amplifier and inverter at regular intervals. On the other hand, the oscillation signal from the oscillation circuit 30 is applied to the center electrode 41 and the peripheral electrode 42 in opposite phases via the inverter 1 to the gates 301, 302, and 303, and is applied to the upper electrode 4 as follows.
When the vehicle is parked horizontally, no pulse voltage signal 30a is generated, and when the vehicle is parked on a slope, a constant pulse voltage signal 30a is generated. When a voltage is supplied from the periodic voltage generation circuit 38, the signal 308 is amplified via the amplifier circuit 31, smoothed by the smoothing circuit 32, and converted into a DC voltage according to the inclination of the vehicle.
Enter.

For the fourth national bond issue (q) and (h), the analog switches 331a and 331b are closed, and the capacitors 332a and 3 are closed.
Voltages are generated at 32b, but since these voltages are the same, the outputs of comparators 341a and 34.1b of comparison circuit 34 are at the ll 1 +4 level. Therefore, the D terminal of the flip-flop 371 of the alarm circuit 37 is ll OIT
Even if the latch signal @(i) is input, the output Q terminal remains at the "1" level, and the alarm circuit 37 does not operate.

During theft, when the vehicle is lifted, the dielectric liquid 2 moves and causes the upper electrode 3 to receive a different pulsed voltage signal 30 than before.
a occurs. For this reason, a voltage difference occurs between the capacitors 332a and 332b of the sample and hold circuit 33. For example, if the voltage of the capacitor 332b is lower than that of the capacitor 332a, then the comparator 3 of the comparison circuit 34
The output of 41b becomes the "01j level." As a result, the alarm = 11- The D terminal of the flip-flop 371 of the circuit 37 becomes "1".
level, and the output terminal Q becomes 1 due to the latch signal (i>
Since the signal reaches the 10 I+ level, the frequency division counter 372 starts frequency division, and the transistor 373 is driven to issue an alarm using a horn or the like. After that, when the terminal Q3 of the frequency division counter 372 reaches the "'1" level, the circuit 4 is transferred to the reset l.
0 is activated, and the alarm circuit 37 and time limit circuit 35 are reset.

In this embodiment, the periodic voltage generation circuit supplies voltage to each operational amplifier and comparator at predetermined time intervals, or may supply voltage all the time.

Furthermore, in this embodiment, two sample and hold circuits store the vehicle's inclination angle alternately at fixed time intervals, and a memory circuit capable of long-term storage stores the vehicle's initial inclination angle at the start of parking. The tilt angle during subsequent parking may be compared with the initial tilt angle.

Furthermore, the liquid in the sealed container 1 may be conductive.

Also, the alarm circuit is reset when the alarm is issued twice by a horn or the like, but it is also possible to continue issuing the alarm until the power supply VB is turned off using a switch (not shown).

[Brief explanation of the drawing]

FIG. 1 is an overall sectional view of the device of the present invention, FIG. 2 is a half-sectional perspective view of a tilt sensor, FIG. 3 is a circuit diagram of a tilt detection circuit, and FIG. 4 is a signal waveform diagram. 1... Sealed container 11... Inner peripheral wall 12... Outer peripheral wall 2... Liquid 3.
... Upper electrode 33 ... Sample hold circuit (memory circuit) 3
4... Comparison circuit 37... Alarm circuit 41... Center electrode (lower electrode) 42...
・Peripheral electrode (lower electrode) 61.62... Printed board 7... Tilt detection circuit agent Patent attorney Motomu Ito Uma 1 diagram

Claims (5)

[Claims] (1) A sealed container fixed to a vehicle and surrounded by an inner peripheral wall and an outer peripheral wall that are flat or circular and whose center curves convexly downward, and a liquid sealed in a volume smaller than the volume of the sealed container. , an upper electrode and a lower electrode that are arranged oppositely on the upper and lower surfaces of a sealed container with the liquid interposed therebetween to form a capacitor, and the capacitance of the capacitor that changes due to movement of the liquid as the vehicle tilts while parked. An anti-theft device for a vehicle, comprising tilt detection means that detects and issues an alarm signal when the capacitance of a capacitor changes by a predetermined amount or more. (2) The upper electrode is provided along the entire surface of the upper surface of the sealed container, while the lower electrode is provided with a center electrode provided along the center of the lower surface of the sealed container, and a center electrode provided concentrically with the center electrode on the outer periphery of the lower surface of the sealed container. The vehicle anti-theft device according to claim 1, comprising a peripheral electrode provided in the vehicle. (3) The vehicle according to claim 2, wherein the inclination detection means is set to detect a difference in capacitance between the upper electrode and the center electrode and between the upper electrode and the peripheral electrode. anti-theft device. (4) The inclination detection means includes a memory circuit that stores the capacitor capacity at the start of parking, and a comparison circuit that issues an alarm signal when the capacitor capacity during parking changes by more than a predetermined amount with respect to the stored capacitor capacity. A vehicle anti-theft device according to claim 1, comprising: (5) The inclination detection means includes a pair of memory circuits that alternately memorize the capacitor capacity at each given period during parking, and the capacitor capacity stored in one memory circuit is stored in the other memory circuit. 2. The anti-theft device for a vehicle according to claim 1, further comprising a comparison circuit that issues an alarm signal when the capacitance of the capacitor changes by more than a predetermined amount.