U.S. patent number 3,639,906 [Application Number 04/767,209] was granted by the patent office on 1972-02-01 for key identification system having key code control.
Invention is credited to Peter R. Tritsch.
United States Patent |
3,639,906 |
Tritsch |
February 1, 1972 |
KEY IDENTIFICATION SYSTEM HAVING KEY CODE CONTROL
Abstract
A type of ordinary key is inserted into an ordinary looking lock
that provides a group of unique tone pairs characteristic of the
code identified by the key. These groups of tone pairs are
transmitted to a central processing unit. The central processing
unit responds to the pairs of frequencies by transmitting
appropriate control signals that unlock or refuse to unlock an
appropriate lock or indicate that the key holder may or may not be
entitled to credit.
Inventors: |
Tritsch; Peter R. (Boston,
MA) |
Family
ID: |
25078814 |
Appl.
No.: |
04/767,209 |
Filed: |
October 14, 1968 |
Current U.S.
Class: |
340/5.66;
340/5.67; 70/277; 361/176; 361/172 |
Current CPC
Class: |
G06Q
20/4037 (20130101); G07C 9/00571 (20130101); G07F
7/08 (20130101); G07C 9/27 (20200101); G07C
9/0073 (20130101); E05B 49/006 (20130101); Y10T
70/7062 (20150401) |
Current International
Class: |
G07F
7/08 (20060101); E05B 49/00 (20060101); G07C
9/00 (20060101); H04q 003/00 () |
Field of
Search: |
;340/149A,171,147
;70/277 ;317/134 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pitts; Harold
Claims
What is claimed is:
1. Apparatus for identifying an ordinary looking key having lands
any of which may be within at least three different height ranges
comprising,
key accepting means for receiving an ordinary looking key and
providing an electrical key signal representative of the
identifying code carried by lands of the received key,
said key accepting means including means responsive to the land of
the received key for providing a large plurality of electrical key
signals each representative of a different code carried by a
different arrangement of key lands and having a signal portion for
each land sensed indicating which of said at least three height
ranges embraces the sensed land,
receiving means responsive to said electrical key signal for
providing one of identification and nonidentification signals,
and utilization means responsive to the identification and
nonidentification signals for providing a predetermined
response.
2. Apparatus in accordance with claim 1 wherein said utilization
means comprises actuating means for establishing an unlocked
condition only in response to said identification signal.
3. Apparatus in accordance with claim 1 wherein said electrical key
signal comprises audio tone pairs with each tone pair associated
with a corresponding pair of lands and one of at least three tones
designating a first land height range and one of at least three
tones designating a second land height range in each tone pair.
4. Apparatus in accordance with claim 1 and further comprising
means responsive to magnets in said lands in the ordinary looking
key for providing said electrical key signal.
5. Apparatus in accordance with claim 1 and further comprising said
ordinary looking key in said key accepting means.
6. Apparatus in accordance with claim 4 and further comprising said
ordinary looking key in said key accepting means.
7. Apparatus in accordance with claim 1 wherein said receiving
means is remote from said key accepting means and said utilization
means and further comprising,
means for transmitting said electrical key signal to said receiving
means,
and means for transmitting at least one of said identification and
nonidentification signals to said utilization means.
8. Apparatus in accordance with claim 6 wherein said receiving
means is remote from said key accepting means and said utilization
means and further comprising,
means for transmitting said electrical key signal to said receiving
means,
and means for transmitting at least one of said identification and
nonidentification signals to said utilization means.
9. Apparatus in accordance with claim 7 wherein said electrical
key, identification and nonidentification signals comprise audio
tone pairs for transmission by said means for transmitting with
each electrical key signal tone pair associated with a
corresponding pair of lands and one of at least three tones
designating a first land height range and one of at least three
tones designating a second land height range in each electrical key
signal tone pair.
Description
BACKGROUND OF THE INVENTION
The present invention relates in general to secure key control and
more particularly concerns a novel system that accepts insertion of
an ordinary looking key, decodes that key and produces an
appropriate response to the decoding, such as unlocking or refusing
to unlock a door or ignition system, or indicating that the key
holder should or should not be entitled to credit.
With the widespread use of credit cards the problem of stolen or
misused credit cards becomes more serious. Furthermore, the problem
of unauthorized persons having access to locked rooms or systems
through picking or otherwise bypassing locks becomes more serious.
Still another problem associated with ordinary locking systems is
that once there is danger of an authorized person having a key to a
secured area, for example, if someone loses a key or an employee
having a key no longer becomes associated with the firm, mechanical
locks must be changed. This changing is both costly and time
consuming. And the authorized personnel must each receive a new key
each time a lock is changed.
Accordingly, it is an important object of this invention to provide
a secure key system.
It is a further object of the invention to achieve the preceding
object with an ordinary looking key that causes unlocking only when
a central control unit determines that the key seeking the
unlocking bears a proper code, a code which may be readily
changed.
It is a further object of the invention to achieve one or more of
the preceding objects with an ordinary looking key that identifies
the key holder as entitled to credit.
It is a further object of the invention to achieve one or more of
the preceding objects with apparatus that is relatively inexpensive
when considered as a whole and reliable in operation.
SUMMARY OF THE INVENTION
According to the invention, encoding means, such as an ordinary
looking key, is inserted into transmitting means that provides a
signal, such as audio tone pairs, representative of the code
carried by the encoding means. Receiving means accepts the encoding
means and provides appropriate identification or nonidentification
signals. If the encoded signal is acceptable, the transmitted
signal may cause a mechanism to unlock, such as unlocking a door or
enabling an ignition system of an automobile. Alternately, it may
transmit a signal back to the transmitting means signifying that
the key identifies an individual with acceptable credit. If the
receiving means identifies the encoding signal as unacceptable, it
will refuse to unlock a lock or identify the key as associated with
one who has no or limited credit. Alternately, the receiving means
could transmit a signal that sounds an alarm or identifies the key
as being stolen.
Numerous other features, objects and advantages of the invention
will become apparent from the following specification when read in
connection with the accompanying drawing in which:
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is block diagram illustrating the logical arrangement of a
system according to the invention;
FIG. 2 is a block diagram illustrating the logical arrangement of a
specific embodiment of the invention in which the encoder is a
standard keylike slot and transmits a dual audio tone over
telephone lines;
FIG. 3 is a block diagram illustrating the logical arrangement of a
credit card checking scheme;
FIG. 4 is a pictorial representation of an exemplary embodiment of
the encoding means for mechanically scanning the code carried by an
ordinary key;
FIG. 5 illustrates an embodiment in which magnets in the key carry
the code and actuate magnetic reed switches;
FIG. 6 is a pictorial representation of the inside of the encoder
of FIG. 5 showing a fiberoptic technique for determining the key
code;
FIG. 7 is a diagrammatic representation of additional aspects of
the encoding system utilizing fiber optics; and
FIG. 8 is a combined block-schematic circuit-pictorial diagram of
an encoding system according to the invention for providing encoded
data in the form of tone signals.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
With reference now to the drawing and more particularly FIG. 1
thereof, there is shown a block diagram illustrating the logical
arrangement of a system according to the invention. A type of
ordinary key 11 is inserted into an encoding transmitter 12 that
provides a signal on transmission means 13 representative of the
code carried by key 11. This code is decoded by decoding receiver
and answering means 14 to provide a response that either does or
does not operate actuator 15, depending upon the relationship of
the signal decoded to predetermined conditions. For example, if
decoder receiver and answering means 14 is set to recognize a
particular code and cause the unlocking of a door, sensing that
particular code causes actuator 15 to unlock the door. Decoding
receiver and answering means 14 may respond to a number of
predetermined codes to effect actuation, and these codes may be
selectively changed at any time.
A feature of the invention is that it may decode remotely, accept
all keys, the decoding combination may be rapidly changed and
accept virtually any number of codes and is especially convenient
for use with electronic or computer control. In contrast, a
conventional key is decoded by the lock at the point of insertion,
normally accepts only a preselected group of keys, has but a single
combination or limited set of combinations that is difficult to
change and normally relies on mechanical implementation to effect
unlocking.
Referring to FIG. 2, there is shown a block diagram illustrating
the logical arrangement of a system for encoding the code carried
by the key in a form that is especially useful for use with
ordinary telephone lines. The encoder 21 includes a slot 22 that
accepts any key code of a selected key type. Typically encoder 21
provides tone pairs, an X tone and a Y tone. Preferably there are
four X tones and four Y tones with a pair comprising one X tone and
one Y tone so that the tone pair identifies one of 16 possible code
bits and is compatible with the touch tone telephone system. This
4.times.4 matrix encoding is represented by the matrix encoder 23
that provides the selection of tone pairs over communication means
13 to modem 24 and then decoding receiver and answering means 14
that appropriately controls actuator 15. Typically inserting the
key in slot 22 closes appropriate relays in matrix encoder and tone
generator 23 that select the appropriate tone pairs for
transmission.
Referring to FIG. 3, there is shown a block diagram illustrating
the logical arrangement of a suitable credit card checking system
according to the invention. There may be an encoder 21 at each
location where credit is desired to be checked feeding an
associated modem 23 that is connected to a corresponding modem 24
at the central location over ordinary telephone lines or other
public communications channels 25. A combining means 26, which may
include multiplexing means for sampling the outputs of modems 24
and coupling them in sequence to an adapter 27 may function to
present the data on the different lines to data processing means
31, preferably in digital form. The data processing means 31 may
typically be a general purpose computer or a decode-encode
generator of the type used in cryptology. The data processing means
31 may then compare the data with appropriate information in memory
means 32 and provide a signal on output line 33 that may
distributed by combining means 26 back to the then sensed one of
modems 24 for transmission back over the public communication
channels 25 to an associated one of modems 23 and provide an
indication of the credit status of the individual associated with
the inserted key. For example, the interrogating local station
might include three lights, one of which is actuated. Illumination
of a green light indicates a specifically good credit check; amber,
not more than a predetermined amount; and red that credit should
not be extended and probably that appropriate authorities should be
immediately alerted. The central location may also include similar
indicating means.
The data processing means 31 and memory means 32 may comprise a
general digital processing system having both a drum and core
memory. The core memory may function as executive or director,
carrying sets of criteria for key recognition and associated
action. A high-speed tape reader and punch may be utilized for
entering and receiving information for permanent inventory. The
system could be used to check credit in that the bad credit risks
might be stored on the drum, and the key code would be compared to
these bad risks. Specific central systems are known in the art and
are not described here to avoid obscuring the principles of this
invention.
An especially suitable transmission medium is the telephone system
adapted to carry the touch-tone frequencies used by the telephone
company. There are eight frequencies available arranged in a
4.times.4 matrix to facilitate encoding one out of 16 discrete
values as a combination of two frequencies. To avoid tolerance
problems in determining pin heights of a lock cylinder having pins
displaced in accordance with the configuration of peaks and valleys
in a conventional key, it has been found to be advantageous to
decode the pin height into four levels whereby contiguous pairs of
pins would select the frequency pairs so that two successive pin
heights could be transmitted as a two frequency signal in
accordance with already acceptable telephone company standards.
Although more pin pairs and more discernible pin height would
provide many possible combinations, a special key that looks
different from the average key may be required. The different
appearance of such a key might compromise the security of the
system, a feature of the invention being that the coded key looks
like any other key. This possible problem posed by this
implementation may be overcome by using two common keys with six
pins each, thereby providing 2.sup.24 combinations if the keys are
inserted in proper sequence.
Referring to FIG. 4, there is shown a means for scanning the code
carried by the key 11. A stationary cylinder guide 41 carries a
moving cylinder 42 that is urged rearward against spring 43 inside
dash pot 44 when key 11 is inserted. Spring 43 then urges moving
cylinder 42 back along key 11 to scan its projections and
depressions in sequence. FIG. 5 shows an embodiment of the
invention in which key 11 carries small imbedded magnets, such as
45, 46, 47 and 48 for actuating respective ones of magnetic reed
switches 50 when key 11 is fully inserted. Respective ones of the
reed switches 50 may sequentially activate tone oscillators to
transmit the desired signal sequence. This approach is especially
economical when keys are produced in quantities of 10,000 and
over.
Referring to FIG. 6, there is shown a photoelectromechanical
arrangement for decoding the key. Key 11 is shown inside moving
cylinder block 42. Moving cylinder block 42 is shown with four
spring-loaded pins 51, 52, 53 and 54 having respective caps 55, 56,
57 and 58 formed with openings for transmitting light to an
associated photoelectric transducer through a respective one of
four fiber optical filaments in respective ones of plane 61, 62, 63
and 64. The position of the associated opening allows light to be
transmitted to one and only one of four associated photoelectric
transducers. Thus, pins 51 and 52 denote the tone pair X.sub.1 and
Y.sub.3 while pins 53 and 54 denote the respective tone pairs
X.sub.2 and Y.sub.4. Instead of photoelectric transducers in the
planes 61, 62, 63 and 64, there could be a set of four magnetic
reed switches in each of these planes, and the caps 55, 56, 57 and
58 could be small permanent magnets that would close one, and only
one, of the four reed switches in a respective plane to provide the
appropriate encoding signals.
Referring to FIG. 7, there is shown a diagrammatic representation
of a suitable means for photoelectrically sensing the positions of
the four pins. Fiber bundle 65, 66, 67 and 68 carry light
distributed by plastic block 71 of lucite or other suitable
material from light source 72 to caps 55, 56, 57 and 58,
respectively, of pins 51, 52, 53 and 54. The column of photocells
in plane 64 are energized in the sequence of pins 51, 52, 53 and 54
as moving cylinder block 42 is returned forward. In the specific
configuration shown in FIG. 7, first photocell 71 would be
energized, then photocell 72, then photocell 73, then photocell 74.
Thus, the specific code carried by the key producing the pin
displacement of FIG. 7 is X.sub.1, Y.sub.2 and X.sub.3, Y.sub.4.
Numerous other techniques may be used to encode the key
configuration, such as differential transformers, photosensitive
devices, resistive elements, sliding contacts and the like.
For example, the key lands could mechanically position a number of
lock pins with each lock pin having an opening that is in line with
the other openings only when the key with acceptable code is
inserted. By locating the pins between a light source and photocell
along such line, the photocell is energized to signify acceptance
only when all the lock pin openings are in line.
Referring to FIG. 8, there is shown a combined pictorial
block-schematic circuit diagram of an exemplary encoding means
according to the invention. Inserting key 11 into moving cylinder
42 causes the arm 81 of tip limit switch S1 and 82 of bottom limit
switch S2 to move to the right and energize scan motor 83,
illuminate scan lamp 84 and operate power relay K1 85 to close
normally open contact 86 and keep power on until the scan is
completed while opening normally closed contacts 87 to provide a
reset signal on line 88 as contacts 91 of bottom limit switch S2
are closed. Flip-flops 92 and 93 are thereby cleared. Scan motor 83
then causes moving cylinder 42 to move to the left from the
position 42' back to position 42 so that the photoelectric
transistors scan the four pin positions in sequence.
When a key is inserted, its four key lands raise four corresponding
pins to one of the four levels. In a key having eight key lands,
eight corresponding pins may be raised to one of four levels so
that two of the eight pins will be positioned at the same level.
Then the whole assembly is scan-driven past the vertical stack of
four optical targets, the phototransistors 71, 72, 73 and 74. The
system of FIG. 8 has means for monitoring eight rods serially and
storing the monitored signal in the A register 93 and the B
register 94, each of these registers capable of storing four
bits.
Phototransistors 71, 72, 73 and 74 may typically be Fairchild FPT
100 phototransistors followed by a 7,400N amplifier 95. The latter
is an integrated circuit having photocell amplifiers thereon. The
outputs of the photocell amplifiers 95 are OR-gated in the strobe
gate 96 to trigger a strobe flip-flop 97 and a one-shot circuit 98,
which indirectly gates strobes A and B to the A storage register 93
and B storage register 94. In addition, the one-shot output
triggers flip-flops 92 and 93 for oscillator turn on control
executed by amplifier 101 and relay 102. The outputs 1, 2, 3 and 4
from the photocell amplifiers 95 are connected to the A storage
register 93 and B storage register 94 in pairs with lines 1--4
going to the cells designated 1-4 appended to an appropriate A or
B. Although one data bit is simultaneously presented to both
registers, only one is loaded because strobes and B are mutually
exclusive. Thus, four photocell outputs are stored in eight
register flip-flops.
The eight data bits control eight relay closures of relays and
relay drivers 104. The relay closure grouping conforms to the
AT&T data set specifications, with a separate common for group
A and B.
There has been described a secure key system characterized by
flexibility, security and reliability at relatively low cost when
measured against the advantage of the system. It is apparent that
those skilled in the art may now make numerous departures from and
modifications and variations of the specific embodiments described
herein without departing from the inventive concepts. Consequently,
the invention is to be construed as embracing each and every novel
feature and novel combination of features present in or possessed
by the apparatus and techniques herein disclosed and limited solely
by the spirit and scope of the appended claims.
* * * * *