U.S. patent number 3,822,396 [Application Number 05/335,582] was granted by the patent office on 1974-07-02 for electric locking and unlocking apparatus.
This patent grant is currently assigned to Tokyo Magnetic Printing Co., Ltd.. Invention is credited to Seiichi Kodera, Shunsaku Nakauchi, Mamoru Namikawa, Fumio Watase.
| United States Patent |
3,822,396 |
| Watase , et al. |
July 2, 1974 |
ELECTRIC LOCKING AND UNLOCKING APPARATUS
Abstract
An apparatus for locking and unlocking electric lock with a
magnetic key code signal recorded on a magnetic card is provided.
The apparatus includes a storage device in which a predetermined
signal specific to a particular lock associated is preliminarily
stored, and the key code signal read out from the card inserted
into a read-out device of the apparatus is compared with the
predetermined signal at a logic operation device. Coincidence of
the both signals at the logic operational device will actuate an
associated control device for the electric lock so that the lock
will be unlocked or locked depending on the locked or unlocked
state of the lock.
|
Inventors: |
Watase; Fumio (Tokyo,
JA), Nakauchi; Shunsaku (Tokyo, JA),
Kodera; Seiichi (Tokyo, JA), Namikawa; Mamoru
(Tokyo, JA) |
|
Assignee: |
Tokyo Magnetic Printing Co.,
Ltd. (Tokyo, JA)
|
| Family
ID: |
27292429 |
| Appl.
No.: |
05/335,582 |
| Filed: |
February 26, 1973 |
Foreign Application Priority Data
|
|
|
|
|
| May 11, 1972 [JA] |
|
|
47-45892 |
| Jun 22, 1972 [JA] |
|
|
47-61846 |
| Jun 22, 1972 [JA] |
|
|
47-61847 |
|
| Current U.S.
Class: |
361/172;
340/5.66; 340/5.23 |
| Current CPC
Class: |
E05B
49/00 (20130101); G07C 9/27 (20200101); G07C
9/00571 (20130101); G07C 9/00722 (20130101) |
| Current International
Class: |
E05B
49/00 (20060101); G07C 9/00 (20060101); E05b
049/00 () |
| Field of
Search: |
;317/134
;340/147MD,147CN,149R,149A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Miller; J. D.
Assistant Examiner: Moose, Jr.; Harry E.
Attorney, Agent or Firm: Wolfe, Hubbard, Leydig, Voit &
Osann, Ltd.
Claims
What is claimed is:
1. An electric locking and unlocking apparatus comprising an
electrically controlled lock mechanism, a read-out device for
reading out signals recorded on a magnetic card, a storage device
in which a predetermined signal is preliminarily stored, a logic
operational device for comparing an input signal from said read-out
device with said predetermined signal from said storage device, a
control device for controlling said lock mechanism as activated by
a signal from said logic operational device, and a temporary
storage circuit inserted between said read-out device and said
logic operational device so as to store the signal from the
read-out device, said storage device comprising a plurality of
key-code storage circuits corresponding in number to a plurality of
kinds of keys used so that predetermined key-code signals
respectively independent and corresponding to the respective keys,
said logic operational device comprising a plurality of comparator
circuits to which the output of said temporarily storage circuit
and outputs of said key-code storage circuits are given to compare
the signal from the magnetic card with the respective key-code
signals predetermined and stored in the respective key-code storage
circuits, so that said control device will be actuated upon
receiving outputs from any one of said plurality of comparator
circuits so as to lock or unlock the electric lock.
Description
This invention relates to an electric locking and unlocking
apparatus wherein an electric lock device is locked and unlocked by
a magnetic key code signal recorded on a magnetic card.
While there have been already electric locks in which a light,
magnetism or electricity is utilized, these include a special
electric or magnetic circuit within a lock mechanism itself and is
so complicated in structure and so high in price that these locks
have not yet come to be generally used.
Further, in the above referred cases, it has been comparatively
easy to make a master key and it has been necessary to
simultaneously replace the lock mechanism itself in order to
replace the master key with another.
In the apparatus of the present invention, the key is a magnetic
card which is so formed that, when a magnetic key code signal
recorded on this card is read out and coincides with a specific
signal which is preliminarily provided in the lock mechanism, a
locking or unlocking operation can be made.
A main object of the present invention is to provide an electric
lock apparatus wherein a key code signal recorded on a magnetic
card and a specific signal stored in the apparatus can be readily
altered to a new locking or unlocking code without changing the
magnetic card or lock mechanism itself when the specific signal
stored in the apparatus is changed in conformity with the key code
signal on the card and, further, the locking or unlocking of a
plurality of locks as well as a particular lock therein can be
concurrently concentrically controlled from a remote place, so that
the practicability and security are high.
Another object of the present invention is to provide an electric
lock apparatus which has an adaptability to the locking and
unlocking with a plurality of different key-code signals and yet
the variety of the key code signal can be easily increased without
increasing the amount of information given to the lock nor even
impairing the security of the lock.
A further object of the present invention is to provide an electric
lock apparatus wherein, by reading out a series signal of a key
card and comparing the series signal as it is with a comparative
signal preliminarily stored in the apparatus, so that the output
terminals of the key code storage circuits and the input terminals
of the comparator circuits can be minimized in number as requited
without requiring a series-to-parallel converter and irrespective
of the number of bits of the code signals, whereby the number of
component parts to be used in the apparatus can be decreased and
the formation of the circuit can be much simplified.
The present inventions shall now be explained in detail with
reference to accompanying drawings, in which:
FIG. 1A is a block diagram showing the basic structure of the
electric locking and unlocking apparatus according to the present
invention;
FIG. 1B is a block diagram of an embodiment of the apparatus of the
present invention;
FIG. 2 is an explanatory view showing an arrangement of a card
inserting port and lock mechanism in the present apparatus;
FIG. 3 shows a magnetic card used with the present apparatus;
FIGS. 4A-4E are practical circuit diagrams of the first embodiment
shown in FIG. 1B;
FIG. 5 is a block diagram of a second embodiment of the present
invention.
FIG. 6 is a practical circuit diagram of the second embodiment;
FIG. 7 is an equivalent block diagram to the basic structure shown
in FIG. 1A;
FIG. 8 is a block diagam of a third embodiment.
FIGS. 9 and 10 are diagrams showing wave forms at the respective
parts in the embodiment of FIG. 8 to explain its operation;
FIG. 11A is a practical circuit diagram of the third embodiment;
and
FIG. 11B shows wave forms at the respective parts in the third
embodiment.
In FIG. 1A, which showing the basic formation of the apparatus of
the present invention, 1 is a magnetic head to read recorded
signals out of magnetic cards, 2 is an amplifier to shape and
amplify pulse signals sent from the magnetic head, 3 is a logic
operational device to compare pulse signals from the amplifier 2
with signals preliminarily stored in a storage device 4, and 5 is a
control device to connect a power source 6 and an electric lock
mechanism 7 with each other in response to the results of the
comparison in the logic operational device 3. More specifically, a
predetermined key code signal is recorded on a magnetic recording
part 12 of a recording card 11 as shown in FIG. 3 and the magnetic
card 11 is inserted into a magnetic card inserting port 8 provided
on a wall 9 adjacent a predetermined door 10 as shown in FIG. 2. A
recorded signal reading-out device for reading the key-code signal
out of the magnetic card is provided inside the inserting port 8 so
that the signal will be read out. The signal read out is shaped and
amplified by the amplifier 2 and is sent to the logic operational
device 3. On the other hand, a signal specific to a predetermined
electric lock and separately memorized in the storage device 4 is
also sent to the logic operational device 3 so as to be compared
with the key-code signal read out of the magnetic card 11. In case
the two signals compared in the device 3 do not coincide with each
other, the signals will stop here and the lock will remain locked
or unlocked. In case they coincide with each other, a controlling
signal will be generated in the control device 5, which will
operate to connect the electric lock 7 with the power source 6 so
as to lock or unlock the same in such manner that, if the signal
fed back from the electric lock 7 due to the controlling signal
shows a locked state of the lock 7, the same will be unlocked and,
if said signal fed back shows an unlocked state, the lock 7 will be
locked.
Further, in the apparatus according to the present invention, for
example, an additional means for allowing the control device 5 to
generate the said controlling signal directly may be provided, so
that the locking and unlocking operations may be performed without
using the magnetic card, In this case, a switch means for operating
such additional means may properly be set in a house room so as to
render the apparatus convenient. In this case, further, it becomes
possible to operate a plurality of electric locks connected to the
control device all simultaneously, or a specific one or plurality
of such locks, from a central control room.
In FIG. 1B showing a block diagram of a practical embodiment of the
present invention, 1A is a magnetic head to read out a key code
signal recorded on a magnetic card. 1A' is a magnetic head to read
out a clock signal recorded also on the magnetic card, 2A, 2B, 2A'
and 2B' are amplifiers, 2C and 2C' are wave-form shaping devices,
2D and 2D' are output amplifiers, 3A is a series-to-parallel
converter, 3B is a comparator circuit, 4A is a storage device, 5A
is a control device, 6A is a power source device, and 7A is an
electric lock.
An example of practical circuitry arrangement of the first
embodiment according to the present invention is shown in FIGS. 4A
through 4E. In the present instance, the apparatus is shown as
adapted to the case where the key code signal and clock signal on
the magnetic card are respectively comprising 25 bits.
In FIG. 4A, a key-code signal read out by the magnetic head 1A is
amplified by the amplifiers 2A and 2B and the wave form of the
amplified signal is shaped by the shaping device 2C comprising in
the present instance, for example, a monostable multivibrator. The
shaped signal is then applied through the output amplifier 2D to
"KEY" input terminal of the series-to-parallel converter 3A shown
in FIG. 4B. The clock signal read out by the magnetic head 1A' in
the same manner as in the foregoing is applied, on the other hand,
to "CLOCK" input terminal of the converter 3A in FIG. 4B.
In FIG. 4B, the respective bits of the key-code signal applied to
the "KEY" input terminal are caused to appear sequentially at the
respective terminals M-01 through M-25 in response to the
respective pulses of the clock signal, and are then applied
respectively to "M-01" to "M-25" input terminals of a group of 25
flip-flops in FIG. 4C which forming the comparator circuit 3B
together with a group of 25 diodes shown in FIG. 4D as encircled
and labeled as 3B. FIG. 4C shows only a part of such
flip-flops.
In FIG. 4C, by the key-code signal added to the input terminals
M-o1 to M-25, the flip-flops are operated to store the key-code
signal as a group of 25 bit parallel signals. In FIG. 4D, the
respective storage elements of the storage device 4A are
representing the respective flip-flops of FIG. 4C as simplified,
and output terminals "F01" through "F50" coincide with the
respective corresponding storage elements "F01" through "F50" of
the storage device 4A in FIG. 4D. Therefore, for example, the
output terminal "F01" of the flip-flops represents the storage
element "F01" shown in FIG. 4D.
In FIG. 4D, each of the diodes encircled as 3B is preliminarily
connected to either one of even-numbered and odd-numbered sides of
the output terminals of the respective flip-flops in accordance
with the predetermined key code signal. For example, the leftward
most diode in the drawing is connected at its cathode side to
either one of the output terminals "F01" and "F02" of the
flip-flops, the leftward second diode is likewise connected to
either one of the flip-flop output terminals "F03" and "F04" and so
on. That is, the key-code signal for locking and unlocking the
electric lock can be determined by the manner in which the
respective diodes are connected to the selective one of the two
output terminals of the respective flip-flops.
Further, the diode group 3B is forming an "AND" gate circuit, which
is actuated only when the key-code singal and the predetermined
key-code signal are all coincided with each other so that an output
will be provided at "LS" terminal and such output will be
transmitted to "LS" input terminal of the control device 5A in FIG.
4E as locking or unlock signal.
In FIG. 4E, by the locking or unlocking signal applied to the "LS"
input terminal of the control device 5A, a relay RA is operated to
lock or unlock the electric lock comprising a solenoid and a
mechanical lock mechanism.
Detailed explanation of the control device shown in FIG. 4E shall
be made in the following. In the present embodiment, a DC voltage
of 24V is supplied to a terminal "24VA," and a stabilized DC
voltage of 12V is supplied to a terminal "R12V." When the magnetic
card is inserted in the port 8 shown in FIG. 2, a microswitch
provided in said port (not shown) causes a terminal "PS" to be
connected to the earth so that a relay "RP" will be actuated.
Consequently, a contact rp is closed to apply the DC voltage to
transistors TR1 and TR2 and, at the same time, the DC voltage of
12V is supplied to the respective parts of the present locking and
unlocking device through a terminal "R12VS" coupled to the contact
rp. Further, a reset signal for resetting the respective flip-flops
in FIGS. 4B and 4C is provided to a "RESET" terminal as an
output.
The locking or unlocking signal applied to the "LS" terminal causes
the relay RA to be actuated through the transistors TR1 and TR2.
Consequent thereto, a contact ra2 is closed so as to apply the DC
voltage of 24V to the electric lock comprising a solenoid connected
to an "ST" terminal and mechanical lock mechanism so that the lock
will be locked or unlocked. A contact ra1 is of a selfholding type,
which holds its operation until the contact ra2 opens after the
relay RA is once actuated.
When the magnetic card is taken out of the card inserting port 8
after the electric lock is locked or unlocked, the connection
between the terminal "PS" and the earth is releases. Therefore, the
relay RP becomes non-operative so that the contact rp will open to
interrupt the power supply to the respective parts of the locking
and unlocking device, and the relay RA is also caused to become
non-operative so that the contacts ra1 and ra2 will open, thereby
the locking or unlocking operation for the electric lock is
completed.
Relay RL is provided for the purpose of determining whether the
electric lock is locked or unlocked. It terminal "DL" is to be
connected to the earth when the electric lock is in the locked
state. Relay RT is for the purpose of automatically locking or
unlocking the lock, a terminal "AL" of which is to be connected to
the earth when the lock is in its unlocked state. (Contacts rl and
rt are shown in their locked position in FIG. 4E.) Another relay RD
is provided so as to be utilized at the time when the power supply
from the source is interrupted. In case the power supply is
stopped, the contact rd is caused to be in its leftward position in
the drawing so that, when the electric lock is in its locked state,
a charge in a condenser C1 is supplied through the contact rl to
the solenoid of the electric lock so as to unlock the same.
Terminals "ML" and "MR" are provided so as to adapt the device to
manual locking and unlocking. For this purpose, the terminals are
connected through a push-button or the like to the solenoid of the
electric lock.
According to the thus formed electric locking and unlocking
apparatus of the present invention, the magnetic key code signal
recorded on the magnetic card cannot be normally recognized by
sight from outside and the forgery and illegal use of the card can
be prevented. Further, in case a possibility of the illegal use of
the magnetic card is produced by the loss or theft of the card, the
security will be able to be again secured by only a simple
operation of making the storage device to store an altered new code
signal and, at the same time, making a new magnetic card to store a
magnetic code signal coinciding with said altered new code signal
without requiring such trouble as replacing, adjusting or modifying
the lock mechanism at all. Also, in case it is necessary to release
a plurality of predetermined locks in an emergency case, a
simultaneous unlocking operation will be able to be made at once
through the above mentioned control device without making
individual unlocking operations with magnetic cards. Thus the
electric lock which is very practical and yet high in security can
be obtained.
FIG. 5 shows another embodiment of the present invention, wherein
the variety of keys for locking an unlocking a single lock can be
increased without increasing the amount of information given to the
key.
In the electric lock, as well known, an information of a key code
signal is given to a magnetic card or punched card which
corresponds to the key, is magnetically or optically read and is
compared with a key comparing information preliminarily stored in a
storage circuit of the electric lock and, only when they coincide
with each other, the lock will be locked or unlocked.
In such electric lock, in order that one lock may be locked and
unlocked with a plurality of kinds of keys, such plurality of kinds
of keys as change keys for locking and unlocking a specific lock,
master keys for locking and unlocking a group of different locks of
the change keys, and grand master keys for locking and unlocking a
group of different locks of the master keys are prepared, or the
kinds of keys are increased.
In the case of thus making a plurality of kinds of keys for one
lock, for example, if the total amount of information of the keys
is made 30 bits by using five kinds of keys, the amount of
information will be divided into five parts for each key and,
therefore, the amount of information for each key will decrease.
For example, if each key is formed of 6 bits as equally allotted,
the predetermined key for each lock can be found out relatively
easily at a probability of 1/2.sup.6 = 1/64 and thus there will be
a great problem in the security of he lock.
In order to reduce the probability of the lock being purposely
unlocked, the amount of information may be increased instead of
dividing and allotting the total amount of information to the
plurality of kinds of keys. That is, if the total amount of
information is made of 150 bits with five kinds, the probability of
the lock being purposely unlocked will be 1/2.sup.30 and it will be
impossible to find out the predetermined key or master key.
However, such large amount as a total amount of information of 150
bits is difficult to make from the size or the like of the magnetic
card for recording the key-code signal and has a defect of
complicating the formation of such circuit as the comparator
circuit in the electric lock.
After once setting a purality of kinds of keys, in order to
increase the kinds, as the amount of information has been divided
and allotted, it is necessary not only to change the design of the
entire electric lock but also to change the information to be given
to all the keys distributed to the users. It is substantially
impossible.
In the embodiment in FIG. 5 showing in a block diagram an apparatus
in which the above mentioned defects are eliminated, 21 is a code
read-out circuit, 22 is a temporarily storage circuit, and 23 is a
plurality of keycode storage circuits provided in parallel, which
are represented by references 23-1, 23-2 - - - 23-5, respectively.
24 is a plurality of comparator circuits provided in parallel,
which are represented by references 24-1, 24-2, - - - 24-5,
respectively. 25 is an "OR" gate circuit and 26 is an electric lock
which can be locked and unlocked with an electric signal, The code
read-out circuit 21 may be provided, as required, with an amplifier
in case the output is small and with a shaping circuit or the like
in order to shape the wave form.
The above second embodiment of FIG. 5 is formed by fixing a total
amount of information irrespective of the increase of the kinds of
keys. For example, if the total amount of information is made 30
bits and the kinds of keys are made five kinds, similarly to the
foregoing, 30 bits of the total amount of information will be
allotted to the respective keys of five kinds and thus five kinds
of keys will be made for one lock but the probability of this lock
being purposely unlocked with other keys than a predetermined key
will be 5/2.sup.30, it will be substantially impossible to unlock
it and the security of the lock will be well secured.
On the other hand, in the circuit formation of the present
apparatus, the key-code storage circuits 23 and the comparator
circuit 24 may be respectively increased in response to the number
of a plurality of kinds of keys and, in the case of 5 kinds of
keys, respectively 5 of these circuits may be set in parallel. The
key-code comparing information to be stored in the key-code storage
circuits 23 is formed of 30 bits in the same manner as the key-code
information. For example, the information of the individual key is
stored in the circuit 23-1, the information of the master key is
stored in the circuit 23-2, and in the same manner, the information
of the fifth key is stored in the circuit 23-5.
Now, if the key-code information recorded on the magnetic card or
the like comes in, it will be read out by the read-out circuit 21
and will be sent to the respective temporarily storage circuits 22.
The key-code information thus read out is temporarily stored in
respective said storage circuits 22 and is sent out simultaneously
to a plurality of respective comparator circuits 24 provided in
parallel.
In the comparator circuits 24 having received the key-code
information, the key-code information is compared simultaneously in
parallel with the respective key-code comparing informations stored
in a plurality of the key-code storage circuits 23. That is, in the
comparator circuit 24-1, the key-code information is compared with
the key-code comparing information from the key-code storage
circuit 23-1. In the comparator circuit 24-2, the key-code
information is compared with the key-code comparing information
from the storage circuit 23-2. In the same manner, the respective
informations are compared simultaneously in parallel.
As a result of such comparison, in case the key-code comparing
information coincides with the key-code information, a signal will
be sent to the "OR" gate circuit 5 from the comparator circuits 24
but, in case it does not coincide, no signal will be generated.
Therefore, in the "OR" gate circuit 25, if a signal comes from any
of the comparator circuits 24, a locking or unlocking signal will
be sent to the electric lock 26 to lock or unlock it. If no signal
comes from any of the comparator circuits 24, there will be no
output from the "OR" gate circuit 5 and, therefore, the key is
discriminated not to be the specific predetermined key and the
electric lock cannot be locked nor unlocked.
The example wherein five kinds of keys are prepared from the first
has been explained in the above. However, in such case that two
kinds of keys are prepared at first and then the kinds of keys are
further increased, two key-code storage circuits 23 and two
comparator circuits 24 are respectively set and then the key-code
storage circuits 23 and the comparator circuits 24 may be increased
in parallel by the number of the kinds of keys to be increased.
Therefore, it is very easy to increase the kinds of keys.
Further, it is possible that respective numbers of the circuits
expected to be required in future are set from the first but only
the circuit functions of actually not required circuits are
retained stopped, so that not only the circuit functions will be
recovered in the case of increasing the kinds of keys but also the
kinds of keys will be able to be decreased at a later stage.
As described above, according to the second embodiment, the kinds
of keys can be easily increased without increasing the amount of
information given to the key nor impairing the security.
FIG. 6 shows an exemplary practical circuit of the second
embodiment, wherein 21 is a read-out circuit, 23 is a plurality of
temporarily storage circuits, 24 is a plurality of comparator
circuits, 25 is an electric lock, 26 is an addressing circuit for
the storage circuits, and M1 to M5 are respective storing devices
of the storage circuits 23.
FIG. 7 shows an equivalent circuitry block diagram to the basic
structure of FIG. 1 for explaining the key-code signal comparison
performed in the structure. Generally, when a key-code signal
recorded in series on the magnetic card or the like comes in, it
will be read out as a series signal in a read-out circuit 71 and
the series signal thus read out will be temporarily stored in a
series-to-parallel converter 72 and will be converted to a parallel
signal. This parallelly converted output is sent to a comparator
circuit 73.
On the otherhand, from a key-code storage circuit 74, a key-code
comparing signal preliminarily stored therein comes as a parallel
output into the comparator circuit 73 simultaneously with the
parallel output of the key-code signal.
In the comparator circuit 74, the key-code signal and key-code
comparing signal are compared with each other parallelly
simultaneously to see whether all the signals coincide. In case
they coincide, the signals will be sent to an electric lock 75 to
lock or unlock it.
In such electric locking and unlocking apparatus, as the signals
are compared parallelly simultaneously, the output terminals of the
series parallel converters and key-code storage circuits and the
input terminals of the comparator circuits are required by the
number of the bits of the signals. For example, if the signal is
formed of 40 bits, 40 sets of input terminals will be required for
the key-code signal and key-code comparing signal in the comparator
circuit. Therefore, there arises a defect that the component parts
forming each circuit are many and that the circuit formation is
thereby complicated.
In the third embodiment of FIG. 8, such defects are eliminated by
comparing the key-code signal as a series signal as it is.
In the block diagram showing the third embodiment in FIG. 8, 81 is
a read-out circuit, 82 is a comparator circuit 83 is a key-code
storage circuit, 84 is a coincidence storage circuit, 85 is an
"AND" gate circuit, and 86 is an electric lock. As required, the
read-out circuit 81 may be provided with an amplifier in case the
output is small, or with a shaping circuit or the like in order to
shape the wave form.
In FIGS. 9 and 10 showing wave forms at the respective parts in the
embodiment of FIG. 7. In particular, FIG. 9 shows wave forms in
case the key-code signal and key-code comparing signal coincide
with each other and FIG. 10 shows wave forms in case these signals
do not coincide.
Now, if a signal of a key recorded in series on a magnetic card or
the like comes in, it will be read out as a series signal in the
read-out circuit 81 and the signal thus read out (exemplified as
S.sub.1 in FIG. 9 and S.sub.2 in FIG. 10) will be sent as a series
signal as it is to the comparator circuit 82. Further, a part of
the signal read out will be sent as a clock signal to the key-code
storage circuit 83 from which a key-code comparing signal S.sub.0
preliminarily stored therein (shown in FIGS. 9 and 10) will be
triggered by said clock signal and taken out in the form of a
series signal so as to be sent to the comparator circuit 82.
In the comparator circuit 82, the key code signal S.sub.1 (or
S.sub.2) and key-code comparing signal S.sub.0 are compared with
each other as series signals as they are. As a result of the
comparison, in case both signals all coincide, that is, in case the
key-code signal is S.sub.1 as shown in FIG. 9, a signal S.sub.3
will be sent to the coincidence storage circuit 84 from the
comparator circuit 82 and a signal S.sub.5 of a constant level (a
low signal here) will be sent to the "AND" gate circuit 85 from the
coincidence storage circuit 84.
On the other hand, as an end signal that the key-code signal
S.sub.1 has been all completely read out is given to the "AND" gate
circuit 85 from the key-code storage circuit 83, an "AND" with the
signal S.sub.5 is taken and, with its output signal, that is, a
locking and unlocking signal S.sub.7 (a high signal here), the
electric lock 86 is locked or unlocked.
Further, in case the signals do not coincide, that is, in case the
key-code signal is S.sub.2 as shown in FIG. 10, a signal S.sub.4
having pulses in the non-coinciding part will be sent to the
coincidence storage circuit 84 from the comparator circuit 82. As
said storage circuit 84 is so formed as to reverse the polarity
only when the signals do not coincide with each other, an output
signal S.sub.6 is generated by the signal S.sub.4 and is sent to
the "AND" gate circuit 85.
On the other hand, an end signal that the key-code signal S.sub.2
has been all completely read out has been given to the "AND" gate
circuit 85 as described above but the "AND" with the signal S.sub.6
can not be taken and, therefore, no output comes out of the "AND"
gate circuit, thus no locking and unlocking signal is given to the
electric lock 86, only a signal S.sub.8 is sent and therefore the
electric lock 86 can not be locked nor unlocked.
In the third embodiment, as a series signal of a key code is read
out and is compared as a series signal as it is with a key-code
comparing signal preliminarily stored as referred to in the
foregoing, there are advantages that the output terminals of
key-code storage circuits and the input terminals of comparator
circuits can be minimized as required without requiring
series-to-parallel converters as before and irrespective of the
number of bits of signals, that the number of component parts to be
used can be decreased and that the circuit formation can be
simplified.
FIG. 11A shows a practical circuit diagram of the third embodiment.
FIG. 11B shows signal wave forms at the respective parts in the
circuit of FIG. 11A.
* * * * *