U.S. patent number 3,599,454 [Application Number 04/889,405] was granted by the patent office on 1971-08-17 for key reader and identifier system.
This patent grant is currently assigned to Sargent and Company. Invention is credited to Charles A. Bauer, John A. Hill.
| United States Patent |
3,599,454 |
| Hill , et al. |
August 17, 1971 |
KEY READER AND IDENTIFIER SYSTEM
Abstract
A strictly mechanical key is used both as an
information-carrying medium and as a device for mechanically
unlocking a lock in a conventional manner. The information stored
on the mechanical key is read at an independent station prior to
use in the mechanical lock. The intelligence imparted to the
station is of significance in permitting or not permitting the
functioning of the lock.
|
Inventors: |
Hill; John A. (New Haven,
CT), Bauer; Charles A. (Woodbridge, CT) |
|
Assignee: |
Sargent and Company (New Haven,
CT)
|
| Family
ID: |
25395027 |
| Appl.
No.: |
04/889,405 |
| Filed: |
December 31, 1969 |
| Current U.S.
Class: |
70/125; 70/265;
70/283; 70/460; 340/5.7; 340/5.32; 340/5.33; 70/277; 70/434;
340/5.67 |
| Current CPC
Class: |
E05B
35/001 (20130101); E05B 49/004 (20130101); G07C
9/27 (20200101); Y10T 70/675 (20150401); Y10T
70/8081 (20150401); Y10T 70/713 (20150401); Y10T
70/8811 (20150401); Y10T 70/5301 (20150401); Y10T
70/7062 (20150401) |
| Current International
Class: |
E05B
35/00 (20060101); E05B 49/00 (20060101); G07C
9/00 (20060101); E05b 047/04 (); E05b 047/06 ();
E05b 063/14 () |
| Field of
Search: |
;70/265,277,283,434,460 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Craig, Jr.; Albert G.
Claims
What I claim is:
1. A key identifier system and unlocking arrangement for a closure
comprising a key, mechanical lock adapted to be operated by said
key, linkage means for physically sensing information present on
said key in the form of preselected varying dimensional
configurations, electric supply means, electric switch means for
converting said information into a plurality of electric pulses,
computer means for comparing said plurality of electric pulses with
plurality of recorded pulses previously supplied to said computer
means, electric responsive means associated with said lock and
normally conditioned to prevent unlocking of said closure by
operation of said mechanical lock with means of said key lead means
for supplying signal from said computer means to said electric
responsive means upon proper comparison of said pulses for
conditioning said electric responsive means to permit unlocking of
said closure.
2. The system of claim 1 wherein the electric responsive means
comprises an electromagnet having armature means adapted to prevent
operation of said mechanical lock.
3. The system of claim 1 wherein the electric responsive means
comprises an electromagnet having means adapted to release said
closure whereby to permit the opening of said closure with
operation of said mechanical lock by means of said key.
4. The system of claim 1 wherein the key has a plurality of
longitudinal surfaces and said varying dimensional configuration
are pits in spaced relationship along at least one of said
longitudinal surfaces.
5. The system of claim 4 wherein the electric switch means includes
a plurality of switch means mounted radially with respect to said
key when said key is moved into position for physically sensing
information, and said linkage means includes pins adapted to ride
on said longitudinal surfaces and into said pits and thereby turn
said switch means into an on or off position as said key is
moved.
6. The system of claim 5 wherein said linkage means includes a key
carrier means interposed between said switch means and that portion
of the key having said longitudinal surfaces, said carrier means
adapted to be moved past said switch means, said carrier having
apertures to permit access of said pins to at least one of the
longitudinal surfaces of said key.
7. The system of claim 6 wherein the key carrier means has
information present thereon in the form of preselected varying
dimensional configurations.
8. The system of claim 1 wherein the series of electric pulses are
supplied sequentially.
9. The system of claim 1 wherein the series of electric pulses are
supplied as a group.
10. The system of claim 1 wherein delay means is included for
maintaining and limiting the duration of said electric responsive
means in a positive position thereby obtaining limited but
sufficient time to operate said mechanical lock by means of said
key.
11. The system of claim 1 wherein printout means is cooperatively
associated with said computer means whereby a permanent record of
said information on said key is obtained.
Description
BACKGROUND OF THE INVENTION
It is well known that many government and private installations
have proscribed areas, that is, areas to which access is obtained
only under certain conditions. In the usual manner, the proscribed
area is maintained in a secure fashion by a fence, wall or a
complete housing. Ingress is limited to a few specially manned
locations. In other words, guards are present at such openings.
Individuals having permission to enter the proscribed area are
usually given passes of some kind. When the pass is presented to
the guard at the manned opening and the guard is satisfied that the
individual carrying the pass has a right thereto, the guard will
permit access. It will be quickly appreciated that the cost for
maintaining a series of openings in an installation can be and is
enormous. Further, such costs are multiplied when the installation
is operated on a 24-hour basis as is often the case resulting in a
plurality of guard shifts.
Without hesitation, those skilled in the art and familiar with
problems relative to the responsibility of maintaining and
operating proscribed areas will appreciate that reducing the manned
force necessary to secure a proscribed area would result in a great
financial saving. Prior art workers have made some strides in
achieving partial success in suggesting a solution to the problem
of manned guard stations. In one aspect a plastic laminated card of
the type used in the fabrication of passes has been used. The card,
besides having the usual indicia thereon such as photograph and
thumbprint, etc., also has additional coded information in the form
of, for instance, suitably positioned electric conducting elements
of magnetic ink indicia. In this arrangement reading means is
employed to "read" the information position on the card. If the
intelligence imparted therefrom meets a certain predetermined
criteria, a door associated with the means is automatically
unlocked thereby permitting the card holder to obtain access to the
proscribed area. If the setup includes a door which must also be
unlocked by mechanical means, then the card holder must be in
possession of two instrumentalities, that is, a key and
indicia-carrying card.
ADVANTAGES OF THE PRESENT INVENTION
The present invention seeks to obviate the need of two
instrumentalities by combining in one element the feature of
carrying definable information and being adapted to mechanically
unlock a lock under the aegis of the proper prior-imparted
intelligence. Additionally, the system contemplated within the
purview of the instant invention includes means to positively
identify the specific element employed, means to identify the
station at which the element is employed, and means to identify the
time when the element is utilized. All of such information is
recorded for future review. Additional features and advantages will
become apparent from a detailed consideration of the invention as
it is presented below.
BRIEF DESCRIPTION OF THE INVENTION
The present invention relates to the use of a key which may operate
a tumbler lock of conventional configuration. In addition thereto
the system includes electric switching means proximate to the lock
mounted on a door or designed to release a door from a latched
position. The switching means includes a plurality of switches
mounted in a suitable housing. The switches are in an "off" or "on"
position in sequence to the cut notches in a key of conventional
configuration.
Preferred in the instant invention is a key of the type disclosed
in U.S. Pat. No. 3,303,677. It will be seen therefrom that a key is
disclosed having spaced drilled cone pits positioned longitudinally
on one or more surfaces of a key. By having six sides the key may
have the pits along any one or all of the sides. As stated in said
patent the pins of a tumbler lock may be located in any one of a
plurality of radial directions with the key as the axis of the
tumbler.
In the electric switching part of the present invention, the pins
which protrude into the pits operate electric switches so that they
are in the "off" or "on" position as desired. For purposes of
discussion herein, it will be presumed that as the pins of the
switches are deployed into the pits of the key the switches are
turned "on" so that those pins when deployed in the pits are "on",
i.e., in their normal position. Those pins when riding on the land
portions of the key are in an "off" position.
The information from the key is fed as the input to a computer
which samples the information for storage purposes and for
comparison with the already programmed information. When the
intelligence received compares favorably with the expected, the
computer transmits the information to a mechanically operable lock
to permit its operation by the said key which is transferred from
the sensing or reading station to the mechanical lock.
The release mechanism in association with the mechanical lock may
take the form of a solenoid which removes a stop means normally
positioned to prevent a cam from operating, of a type frequently
found in a tumbler cylinder lock. The lock may be mounted in the
door in the usual manner. Of course, the lock may be mounted on or
near the jamb of a door with the bolt keeper in the door itself. In
another embodiment the solenoid need not even be directly
associated with the mechanical lock but may be operated to retract
an independently operated bolt either moving it from an appropriate
keeper in the doorjamb or from the door itself so that the lock is
again not mounted on the door.
When the electrically operated solenoid is not mounted to directly
defeat the mechanical lock, the key, if proper, will always unlock
the lock but further progress in opening the door cannot be made
until the door is electrically unlatched which is dependent upon
the initially imparted information.
Of course, it is within the purview of the instant invention to
provide other solenoid-operated release means. For instance,
instead of the mentioned stop means, the solenoid could be adapted
to remove an obstruction in the keyway, thereby permitting entrance
of the key. The obstruction may take the form of a shield to the
opening of the keyway or may take the form of means restraining one
or more pins in the cylinder lock from operating.
DETAILED DESCRIPTION OF THE INVENTION
The Drawings:
FIG. 1 is a front view of the key identifier and lock as seen upon
approach.
FIG. 2 is a front view of another embodiment.
FIG. 3 is a front elevation of a fragmentary portion of a door
showing a lock.
FIG. 4 is a side elevation of a fragmentary portion of a door with
a portion broken away.
FIG. 5 is a view taken along lines 5- 5 of FIG. 4.
FIG. 6 is a further fragmentary view of FIG. 4 with the armature of
a solenoid withdrawn.
FIG. 7 is another embodiment of the arrangement shown by FIGS. 3 to
6.
FIG. 8 is a front perspective view of the key identifier with the
front plate exploded from the housing.
FIG. 9 is a rear perspective view of the key identifier with the
rear housing exploded therefrom.
FIG. 10 is a front view of the key identifier.
FIG. 11 is a cross-sectional view taken along lines 11-11 of FIG.
10.
FIG. 12 is a cross-sectional view of the key identifier taken along
lines 12 -12 of FIG. 10 with the key fully inserted.
FIG. 13 is a plan view of an embodiment of a key utilizable in the
present invention.
FIG. 13A is a cross-sectional view taken along lines 13A- 13A of
FIG. 12.
FIG. 14 is a cross-sectional view of the key taken along lines 14-
14 of FIG. 13.
FIG. 15 is a cross-sectional view of the key identifier taken along
lines 15- 15 of FIG. 12.
FIG. 16 is a front perspective view of another embodiment of the
key identifier of the present invention.
FIG. 17 is a perspective of the key carrier used in this other
embodiment.
FIG. 18 is a cross-sectional view of the key identifier of this
embodiment at the beginning of operation.
FIG. 19 is also a cross-sectional view with the key in the final
state.
FIG. 20 is a partial cross-sectional view of this embodiment of the
key identifier.
FIG. 21 is a radial fragmentary cross-sectional view of the
embodiment of FIG. 20.
FIG. 22 is a fragmentary cross-sectional view taken along lines 22-
22 of FIG. 20.
FIG. 23 is a block diagram of the circuitry involved.
FIG. 24 is a block diagram of the circuitry of another
embodiment.
FIGS. 1 and 2 depict the view of a door with a mechanical lock 11
in the door 10 itself. In FIG. 1, to the side of the door, in the
wall 8, is the key identifier of the present invention. In FIG. 2
the key identifier is actually mounted in the door as is the
mechanical lock 11. In each instance, of course, the lock could be
mounted in the doorjamb rather than in the door.
The individual desiring ingress through door 10 must first insert
his assigned key into the keyway of key identifier 9. If the key
has the proper indicia thereon a light on the key identifier will
signal acceptability. At this point the key is removed from the key
identifier and is inserted in the lock in the conventional manner
and the lock is unlocked. If the individual had directly used his
key to unlock the lock without verification by the key identifier,
the unlocking step for the door would not have been achieved.
Of course, it will be appreciated that the door to be opened may
only be a closure of some sort recognized as a barrier which can be
opened for access purposes.
Directing particular attention to FIGS. 3, 4, and 5, a mechanical
lock 11 is mounted in a door 10. The top portion of a trim plate 12
is shown in FIG. 3. The lock has a bolt 13 which moves into the
adjoining jamb 14 through a strike 15. The cylinder 16 of the lock
has been modified in this embodiment to include a solenoid 17 with
its armature 18 in a forward position, that is in engagement with a
centrally located counterbore 19A in cam 19 to prevent its
rotation. The cam 19 is suitably secured to the barrel 20 as by
screws 21. The solenoid 17 is suitably connected to electric
conductors so that it can be selectively energized whereby the
armature is retracted as in FIG. 6 so that the barrel may be
rotated when a proper key has been inserted in the lock.
FIG. 5 shows the cam 19 in dotted lines as the angular movement is
imparted thereto whereby the bolt 13 is withdrawn from its strike
15.
In FIG. 7 another embodiment of the system is illustrated, where
the lock 11A as illustrated does not possess the built in solenoid.
Rather a separate electric lock 22 is employed which is
electrically operated and is in the unlocked position upon
establishment of proper intelligence in the key identifier 9. The
electric lock comprises a solenoid which operates through suitable
mechanical linkage to withdraw a bolt from a keeper upon electric
energization. Suitable resilient means urges the bolt into engaging
position, that is, locking condition when the solenoid is
deenergized.
On the other hand, it has been found useful to maintain normally
armature 18 in the first embodiment and normally the bolt in a
retracted position in the second embodiment so that upon a power
failure the mechanical lock can still be operated. In certain
emergency conditions this will be desirable.
Attention is now directed to FIGS. 8 and 9 for a further
understanding of the key identifier 9. In FIG. 8 the front plate 30
of the key identifier has been removed. The front plate 30 is
attached to main plate 31 by means of a set screw 32. The key
identifier is secured into a recessed position in the wall 8 by a
screw 33 for instance, secured through holes 34. Rearwardly
extending from the main plate 31 is a cup-shaped enclosure 35. From
the enclosure 35 projecting through the main plate 31 and front
plate 30 are two signal lamps 36. Suitable openings 37 in the front
plate 30 are provided as well as corresponding openings 38 in the
main plate 31. One signal lamp exists to indicate that the power is
"on" while the second light indicates when an acceptable key has
been inserted so that it may be transferred to the mechanically
operated lock 11 to unlock the door.
FIG. 9 makes clear the contents of enclosure 35. The enclosure 35
has been exploded from the key identifier. The sensing elements of
the key identifier are mounted in block 39 which may be integral
with the main plate 31. The enclosure 35 is secured to block 39 by
screw 40. The block 39 has four radially extending channels 41.
Each of the channels contains at least one electric switch 42. An
operative assembly pin means 43 extends from each switch radially
into block 39. The switches 42 have suitable wire leads (not shown)
to a male jack assembly 44 which is mounted on support rods 45 and
is held thereon by screws 46 which also pass through openings 47 in
the enclosure 35. Access to the male jack assembly 44 is through an
aperture 48 in the enclosure 35.
From FIG. 8 it will be seen that a key accepting cylinder 50 is in
a forward facing position and is mounted substantially axially with
respect to block 39. A portion of the cylinder 50 projects through
opening 51 of the front plate 30. The key 52 of the six-sided
pitted type is positioned for insertion into the cylinder 50. The
cylinder 50 also extends rearwardly from block 39.
FIG. 10 is a front view of the plate 30 and constitutes a reference
for the cross-sectional views of FIG. 11 and FIG. 12. In regard
thereto, FIG. 11 is a fragmentary view of the signal lamp 36 with
front plate 30 in place on main plate 31 with block 39 rearward of
that. The signal lamp 36 has suitable terminal leads 53 also
directed to the male jack assembly 44.
For an understanding of the mechanical features attendant the
operation of switches 42, attention is directed to FIG. 15. The
switches 42 are operated by assembly pin means 43 which include
pins 54 which are urged outwardly from the switch 42 by helical
spring 55 towards the key 52. Whenever the ends of the pins 54,
which are adapted to fit into the pits 56 of the key 52, actually
move into the pits 56 the switch 42 will operate to either close or
open depending upon the manner in which the information is to be
fed to the computer.
In one embodiment, in operation, the lower most switch 42 acts as
the start switch. This results when the key is first inserted which
forces the pin 54 to operate lower switch 42. The actual operation
is best initiated by having the identifier go into operation when
the pin 54 of the lowermost switch 42 enters the first pit. The
other side and top switches 42 then have pins which move into other
pits on the longitudinal confronting surfaces of the key 52. With
the first pit position, as stated, the computer is turned on, ready
to receive other information and a sync type signal is sent to the
computer instructing the computer to "read" the status of the side
switches and the uppermost switch. For instance, if there are pits
at the side surfaces or top surface of the key then the pins of the
respective switches will dwell therein giving an "on" signal to the
computer. As the key is given further insertion the next pit along
the lowermost surface thereof will again supply a sync signal and
again the other stated switches are read. A key 52 will usually
have a plurality of pits along its underside, the key will be read
on a plurality of occasions. The first pit may be used as both a
turn-on means for the computer as well as a means for supplying a
sync signal. While the intelligence provided in increments may be
digested by the computer in this manner, it is preferred to collate
this intelligence transiently which is then fed to the memory bank
of the computer for comparison. The intelligence transfer is
achieved upon complete insertion of the key, as in FIG. 12,
whereupon the leading portion of the key 52 impinges on switch 42D
which is suitably wired to the computer through male jack assembly
44. While the description in the above gives the impression that
the key is slowly inserted, this is not the case. The key may be
moved in a single rapid motion.
In the event that the intelligence obtained from the key 52
compares favorably with the information expected, the proper lamp
36 will signal acceptability. At the same time lock 11 will be
released for mechanical actuation as in the embodiment of FIG. 4 or
electric lock 22 will be unlocked as in the embodiment of FIG. 7.
In any event a delay system permits the transfer from the key
identifier to the mechanical lock for unlocking purposes leading to
ingress through the now unlocked door 10. The delay period is, of
course, necessary to permit removal from the key identifier to the
mechanical lock without the occurrence of a return to normal
solenoid-caused block.
By employing the configuration of the key 52, the surfaces of the
lower half of the key are employed for the key identifier. The
surfaces of the upper half are coded with pits to operate the
mechanical lock. However, in the above it will have been noted that
the uppermost surface may also have been read. As a matter of fact,
all the surfaces of the key 52 may be read by the key identifier
with the provision of switches to confront all surfaces. Also, the
mechanical lock need not be dependent upon the pits of only the
upper half of the key. It will be evident that a combination of
varying types may be accomplished and utilized without departing
from the scope of the invention.
As far as the information parameters are concerned, the more
information encoded on the key 52 the more difficult will it be to
gain entrance with a trial and error facsimile.
In the embodiment of the invention discussed, the intelligence
imparted is forwarded in increments. In this manner the number of
switches are kept to a minimum, that is, the maximum would be to
include one reading switch for each surface. Even the final switch
42D would be eliminated as intelligence transfer to the memory bank
could be accomplished upon the conclusion of, say, 10 reading
steps. The present invention also contemplates the use of a
plurality of switches along one or more surfaces of the keyway
whereby the key is inserted and the position of each of the
switches is read for simultaneous readout. In this type of
embodiment a great number of switches must be included with a
concomitant greater space requirements and expense in manufacture.
When an unsophisticated computer is employed, a key identifier of
this type may be more advantageously employed.
FIG. 13 and FIG. 14 depict key 52 in enlarged detail. The surfaces
thereof are seen to be appropriately pitted. A ward 52A is included
so that the key can be accepted in only one position thereby
avoiding a spurious signal if the key were inverted and the pits
were not identically positioned along both longitudinal halves of
the key.
FIG. 13A being a cross-sectional view shows radial pin 52B in
cylinder 50. The end of the ping 52B rides in ward 52A.
Again turning to FIG. 15 which is a forwardly directed view of the
switches 42 in reading position on a key 52 which is shown in cross
section. In this view it will be seen that the pin 43 of uppermost
switch 42 terminates in a flat manner so that it cannot project
into any of the pits that may be present along the uppermost
surface of the key 52. In this instance, the uppermost switch is
merely used as an "on" switch as long as the key is present. The
two side switches are the only two engaged in sensing the presence
or absence of pits for purposes of sensing the encoded
information.
FIGS. 16 through 22 relate to another embodiment of the key
identifier arrangement of the present invention. In this embodiment
the key 52 is inserted in a carrier 60 which is mounted in the
cylinder 61. A major portion of carrier 60 projects forwardly from
the front plate 30 (as seen in FIGS. 16 and 18). The carrier as
seen from FIG. 17 has a centrally located keyway 62. It has two
oppositely disposed longitudinal slots 63 thereby providing access
through the carrier 60 to the keyway 62. The slots 63 provide
access for the pins 43A of side switches 42A so that the pits along
the lower sides of the key 52 may be sensed for their presence or
absence thereof. Upper start switch 42A is operated through
alignable pin 64 located in radially located opening 65 of the
carrier 60. The insertion of the key 52 along the keyway of the
carrier raises pin 64 so that pin 43B is pushed upward through its
appropriate channel whereby the switch is turned on. The pin 64 is
of a size so that its upper surface does not project beyond the
carrier, whereby the carrier can move unobstructed rearwardly as
seen from FIG. 19.
The carrier is urged outwardly by helical spring 66 which abuts one
of its ends against an end portion of the cylinder 61 and the other
end against a shoulder of the carrier. When the key is inserted and
pushed the carrier moves toward the switch 42D to signal a readout
as seen from FIG. 19 where the end portion 60A of the carrier moves
to turn switch 42D in an "on" position.
The sync signal from the lowermost switch need not obtain the
signal directly from the key 52. Therefore, no slot 63 is provided.
Rather the bottom of the carrier itself is longitudinally pitted
along the periphery of the carrier 60 as can be more clearly
discerned from FIGS. 20, 21 and 22. A series of pits 67 are located
along the underside of the carrier 60.
In FIG. 21 the side pins 43A project into the keyway 62 of the
carrier 60. Pin 64 projects downwardly, while pin 43C of the
lowermost switch projects upwardly into the initial pit 67 of the
carrier 60. In FIG. 22 a key has been inserted so that the pins 43A
of the side switches can read the absence or presence of the pits
in the key.
In essence the operation of the arrangement of this embodiment is
similar to the previously discussed embodiment except a carrier is
interposed in the reading setup. It will be apparent if more
surfaces of the key are to be read then more switches will have to
be provided along with additional slots to provide access to the
key.
In the foregoing the key 52 has been of the type disclosed in U.S.
Pat. No. 3,303,677. However, other types of keys could be used with
conventional pin tumbler cylinder locks. Of course, the number of
surfaces that could be read would be circumscribed. A combination
key could also be employed where the uppermost and lowermost
surfaces would have the well-known notch configuration while the
sides would be fitted for encoded information.
Having an understanding of the mechanics of the present invention
attention is now directed to FIG. 23. The key identifier station
100 has a number of leads to a transient holding stage 101. Lead
102 is the "on" signal obtained upon initial insertion of the key.
Prior to each readout a sync signal is transmitted over lead 103
while the readout signals are transferred by leads 104 and 105,
more would be required when more than two readout switches are
used. When the readout has been completed the transfer signal
passes through lead 106. The transfer lead 107 carries the total
intelligence to a memory stage of a computer 108 for review by the
stage to determine if the key has met certain predetermined
characteristics. The key has been encoded for not only
acceptability but for number classification so that the computer
can determine to whom the key has been assigned. The results of the
identification and comparison is transferred through lead 109 to a
printout device 110 for a permanent record including information as
to key identifier station source, owner of key, time of use and
acceptability or nonacceptability. A signal is transferred through
lead 111 to a central guard station who can monitor a plurality of
key-identifier stations associated with ingress doors. The computer
stage 108 will send a signal through lead line 107B to transient
holding stage 101 which in turn transmits a signal to the key
identifier lamp 36 through lead 112 and to the electric lock
arrangement 113 through lead 114.
A nonacceptable key will alert the guard by means of a display 115.
The guard may take action such as by closed circuit television
monitoring of the key identifier station giving rise to the
nonacceptable key.
The system of the present invention is particularly versatile as
new keys may be issued on a periodic basis with a change in the
information expected by the computer. The mechanical lock need not
be changed, since in most cases the surface of the key having the
operating indicia for the mechanical lock may remain the same. Of
course by changing the tumblers in the mechanical lock the keys may
be changed in their mechanical operability.
When the key identifier is of the embodiment (mentioned in the
above) which employs a plurality of switches positioned
longitudinally, there is no need for a transient holding stage.
FIG. 24 exemplifies the circuitry involved in a simplified version
of the system. For instance, it will be seen that a plurality of
leadlines 107A connects directly from the key identifier to the
computer stage 108. As all of the information passed from the key
identifier to the computer is accomplished en masse after the key
has been completely inserted, there is no need for the transient
holding stage.
In this embodiment, the printer and display units are not included.
Additionally, the guard station may be eliminated for an even more
simple version.
One of the inherent features attendant the system described in the
above is the fact that the mechanical lock becomes virtually
pickproof. It may be possible for a keyless individual, desiring
entrance, to somehow fool the key identifier to produce a "go"
signal to the mechanical portion of the system. At this point the
keyless individual would have to rapidly pick the mechanical lock.
Since the built-in "delay" would give less than the minimum time
necessary to pick a mechanical lock the keyless individual would
not have sufficient time before the mechanical section is rendered
inoperative again.
In another embodiment of the invention, the closure portion
comprises what is termed a barrier section. The barrier section
consists of a first closure and a second closure. The first closure
may be a revolving door which is released upon receipt of a proper
signal from the key identifier. After passing through the first
closure the individual desiring entrance is presented with the
second closure which is locked with a mechanical lock and may be
unlocked with the same key as used in the key identifier.
While there have been shown and described particular embodiments of
the invention, it will be obvious to those skilled in the art that
various changes and modifications may be made therein without
departing from the invention, and, therefore, it is aimed to cover
all such changes and modifications as fall within the true spirit
and scope of the invention.
* * * * *