 |
Description  |
|
|
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns a novel car anti-theft device comprising a manually
operable key fitted with illuminatable element means and a steering lock
fitted with light sensitive element means.
2. Prior Art
Conventional car keys are identified by their specific shapes and numbers
of key and groove serrations, respectively.
Therefore, the usable range of the keys must be highly limited and thus,
picking possibilities are rather frequent.
In recent decades, however, improvements have been proposed to provide
additional discriminating means in or on the key proper. As an example
thereof, U.S. Pat. No. 4,148,372 may be referred to.
In this prior art device, a manually operable key is inserted into the
steering lock and turned to the START-position. This is the first
condition for starting the engine. An electric resistant pellet has been
embedded in the material of the key. If the resistance value of the pellet
is equal to a preset value specifically allocated to the car, it is
adjudged that a correct manual key has been selected and used. This
constitutes a second condition for starting the engine.
It has been found that the reliance on electric resistance is rather
limitative for the identification of engine keys.
Further, the electric resistance will vary with variation of ambient
temperature and humidity.
BRIEF DESCRIPTION OF THE INVENTION
It is, therefore, an object of the present invention to provide an improved
car anti-theft device by reliance upon more reliable means than an
electric resistor.
It is still a further object to provide an improved car anti-theft device
which is not influenced by ambient temperature and moisture fluctuations.
This and further objects, features and advantages may be attained by
providing a highly improved car anti-theft device which comprises:
a manually operable, vehicle and engine operation controllable key piece
which further comprises:
a pair of electrodes mounted thereon;
an illumination circuit electrically connected with said electrode pair and
adapted for delivery of a specifically preset code signal upon
energization of said electrode pair, and illumination element means which
are caused to illuminate upon reception of said code signal;
a steering lock having a key-reception opening adapted for receiving said
key piece, further comprising:
a pair of electrical terminals mounted a defining wall of said opening and
electrically connectable with said electrodes for conveying voltage coming
from said key piece side, and light-receiving element means coming from
the side of said illumination element means; and lightreception circuitry
adapted for adjudging a coincidence between a signal from said light
reception element means with said preset code signal and adapted for
starting an engine starter and/or making an engine controller, into
operable condition.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a reversible type engine key providing
improvements in accordance with the present invention.
FIG. 2 is a front view of a steering lock assembly comprising a stationary
housing and a rotor mounted rotatably therein.
FIG. 3 is an illumination circuit molded within the engine key.
FIG. 4 is a light reception circuit mounted at the steering lock housing.
FIGS. 5 and 6 are flow charts to be used for the illustration of the
anti-theft device according to this invention.
FIG. 7 is a schematic sectional view of a shaftlocking device fitted with
the steering lock assembly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following, preferred embodiments of the present invention will now
be described more in detail with reference to the accompanying drawings.
In FIG. 1, a manually operable engine key of the up-and-down reversible
type is shown generally at 1 in its side elevation, which has two series
of symmetrical key serrations 1a and 1a' formed on both side edges of the
key proper 1e.
At the root portion of the ignition key 1, a pair of oppositely positioned
electrodes 1b and 1b' are provided on both surfaces of said key proper or
plate, although the latter electrode 1b' is not illustrated in FIG. 1.
However, the latter is schematically shown in FIG. 3. Naturally, these
electrodes or contact 1b and 1b' are electrically insulated from the body
portion 1e of key 1 which is made of a metal, preferably steel.
Symbol 1c represents a unitary grip section made preferably of synthetic
resin material and cast integrally thereon and covering the front and rear
root surfaces of the key proper 1e.
A pair of illuminatable diode elements 1d and 1d' are provided at the two
shoulder portions 1c' and 1c" of grip section 1c in a substantially
embedded manner and direct their illuminating lights toward the tip end of
key 1, when either of them is energized. An illuminator circuit shown
generally with 3 in FIG. 3 which includes said diode pair 1d; 1d', is cast
within the material of said cast-on resin section 1c.
In FIG. 2, a steering lock 2 is shown in its front view having a rotor 2a
formed with a conventional key slot or opening 2a', said blade portion 1e
of the key 1 being naturally able to be inserted thereinto and redrawn
out. An opposite pair of terminals 2b and 2b' are provided in the key
cylinder 2a of steering lock 2 and in a partially exposed manner into the
key slot 2a'.
When the key blade 1e has been inserted into the key slot 2a fully in
position, specifically arranged conventional tumblers (not shown) are
pressed laterally by contact with serrative projections 1a or 1a' formed
on the key edge, and the rotor 2a becomes rotatable by turning the key 1
in the clockwise or counter clockwise direction, as the case may be. In
addition, said terminal 2b or 2b' is brought into electrical connection
with corresponding electrode 1b or 1b' of key 1, respectively.
In this way, current may be supplied to illuminator circuit 3 through
either of these established electrical connections, as will be more fully
disclosed hereinafter.
At the ignition-ON position of steering lock 2, there is provided a light
reception element 2c which is so designed and arranged to receive light
beams issued from illuminator element 1d or 1d', if either one of the
latter has been energized.
In FIG. 4, numeral 4 represents a light reception circuit to which said
element 2c is electrically connected, as shown. This arrangement serves to
make a discrimination of a signal from light reception element 2c whether
it is originated from the vehicle key or not.
Next, referring back to FIG. 3, the illuminator circuit 3 molded in the
resin-made grip section 1c will be described hereinbelow.
In this drawing, said electrodes or contacts 1b and 1b' and illuminator
diodes 1d and 1d' are also shown.
3a represents a polarity conversion circuit which is preferably a diode
rectifier and electrically connected with said electrodes 1b and 1b'. It
should be remembered that the key 1 is the reversible type, since upper
and lower serrations 1a and 1a' are made in the opposite shape to each
other, as seen from FIG. 1. Although a 12-volt current will be supplied
when the electrode 1b or 1b' is brought into electrical connection with
the terminal 2b or 2b' upon insertion of the key 1 into key slot 2a', as
was already described substantially hereinbefore, the polarity of the
current may be either plus or minus, depending upon key insertion attitude
"up" or "down". By provision of polarity converter 3a, a supply of reverse
polarity current to illuminator circuit 3 may be positively prevented.
Control circuit 3b is electrically connected with polarity conversion
circuit 3a, the former being adapted for on-off control of a transistor 3d
by a signal fed to the control circuit 4c to be described; and for feeding
to the latter through closure of ignition switch 4a.
The control circuit 4c is so designed and arranged that when ignition
switch 4a has been closed a voltage is supplied to said terminals 2b; 2b'
and comparison is made if there is a coincidence between the signal fed
from illuminator element 2c and the preset signal stored at memory circuit
4d and further, if there be such coincidence as mentioned above the
transistor 4f is turned on, while, if there be no coincidence, another
transistor 4e is caused to turn on. Therefore, when repeating again, the
memory 4d has stored the code specifically selected out for the car under
consideration.
Symbol 4g represents a relay which becomes conductive if the transistor 4f
is on, thus its movable contact being caused to close.
As shown, transistor 4e is connected with an alarm which is preferably a
buzzer.
Further, movable contact of relay 4g is electrically contact to a starter
interruption relay, not specifically illustrated. In the case of an
automatic clutch vehicle, the electric connection under consideration is
made to such a relay, although not specifically illustrated, which is so
designed and arranged that the starter is caused to operate when the shift
lever, not shown, is positioned. either at the parking or neutral
position.
Finally, the operational mode will be set forth hereinbelow with reference
to flow charts shown in FIGS. 5 and 6.
Now assuming that a correct ignition key specifically attributed to a car
under consideration, as at 1, which represents inventive improvements so
far shown and described, has been selected out and inserted into the key
insertion slot 2a' of steering lock rotor 2a in position, either electrode
1b or 1b' is brought into conductive engagement with terminal 2b or 2b',
respectively. Then, the rotor 2a is rotated with the inserted engine key
clockwise to ON-position, ignition switch 4a is caused to close and
voltage energy is supplied to terminal 2b or 2b' from current source.
Thus, illuminator circuit 3 is caused to operate in the aforementioned way
and control circuit 3b reads out the code from storage 3c, and a pulse
signal is fed to transistor 3d. In this way, the transistor 3d is caused
to on-off operate so as to make on-off operation of illumination diode 1d
in accordance with said pulse signal.
Successive light beams will be delivered from said illumination diode 1d,
1d' to light reception element 2c which delivers in turn a corresponding
light pulse signal which is then fed through input/output circuit 4b to
control circuit 4c. The latter circuit 4c reads out this pulse signal as
well as the preset signal from memory circuit 4d.
And, therefore, a comparison is made between the input signal and the
preset signal and a comparison job between these both signals will be
made. When there is a coincidence, in this sense, an output will be fed to
transistor 4f for turning the latter on.
Current is, therefore, fed to relay 4g and thus, its movable contact is
closed and an output is fed to the starter interruption relay for
operating the starter motor, not shown.
On the contrary, if a false or incorrect engine key is used, the steering
lock rotor 2a will be rotated. However, in this case, the key is not
fitted with an illumination diode and thus, the element 2c receives no
light and no further action will be made at light reception circuit 4.
By rotation of the rotor 2a with use of the false key, current will also be
fed to the key blade 1e, and illumination element 1d will be caused to
make on-off operations, the mode of which is, however, different from the
read-out signal from the memory 4d. Thus, control circuit 4c determines
that there is a lack of coincidence and an output will be fed to another
transistor 4e. By this operation, the alarm will be operated so as to give
notice to the driver or other responsive person of the possibility of a
key misuse or a possible picking of the lock.
In, in the foregoing embodiment description, the engine starting has been
described only as an explanatory example. Any person skilled in the art
will easily think of similar applications as with a car trunk, openable
car roof or the like appliances.
Further, with reference to FIG. 7, the locking operation per se will be
described only briefly, taking the case of steering shaft locking and
unlocking operations.
The forward end of the rotor 2a of lock 2 is operatively connected
coaxially with a rotator 9 which is formed rigidly with a rotary cam,
preferably a sector cam 8, kept in pressure contact with a hanger 10. This
hanger 10 supports a conventional steering shaft locking bolt 15 which can
slide up-and-down as in FIG. 7. The lowermost end of this locking bolt is
brought into engagement with a recess, not shown, of the steering shaft,
not shown. FIG. 7 represents such a shaft-locking state. There is an
urging spring 13 provided between a stationary cap member 2d and said
hanger 10, for urging the locking bolt towards its locking direction.
With operational rotation of the rotor 2a of lock 2, upon proper insertion
and rotation of the key 1 in the aforementioned way, the rotator and
hanger are caused to move upwardly against the action of the urging spring
13, so as to raise or recede the locking bolt 15 from its shaft locking
position to its unlocking position.
When the key is turned in the opposite direction, the locking bolt 15 is
caused to advance downwards under the action of spring 13 until the tip
end of bolt 15 has been brought into engagement with the recess of the
steering shaft for locking the latter.
As the light medium for signal transmission usable in this invention,
infrared light may most preferably be employed.
Although the present invention has been described in the foregoing with
particular reference to a preferred embodiment, it should be understood
that this is merely illustrative and not restrictive, and any change and
modification may be effected within the spirit and scope of the present
invention as recited in the appended claims.
* * * * *
|
|
 |
|
 |
Description |
|
