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Claims  |
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What is claimed is:
1. An electric lock system comprising a plurality of locks and a plurality
of card keys, each of said card keys being arranged for opening any of
said locks;
each of said locks and each of said card keys having at least one related
communication port thereon so that when a card key is positioned with
respect to one of said locks, said communication ports are positioned for
communication;
means in each said card key for electronic storage therein of a unique card
key identification number;
means in each said card key for receiving and storing a personal
identification number of a card key user;
an invalid card key identification number register in each said lock and an
invalid card key identification number register in each said card key;
means for updating said invalid card key identification number register in
said lock from said invalid card key identification number register in
said card key when said card key is placed in communication with said
lock;
means for updating said invalid card key identification number register in
said card key from said invalid card key identification number register in
said lock;
means for inhibiting access to all functions including opening of said lock
by a card key when its card key identification number is listed in said
invalid card key identification number register in said lock;
a security number register in each said lock and a security number register
in each said card key, each said security number register having
successive security states;
means for advancing said security number register in said lock from one
state to the next in one direction only when said security number register
in said card key is ahead of said security number register in said lock;
means for erasing said invalid card key identification number register in
said lock and in said card key when said security number register is
advanced;
means for inhibiting access to all functions including opening of said lock
when said security number register of said lock is advanced beyond said
security number register of said card key;
means for determining the correctness of a correlation between the personal
identification number stored in the card key and the personal
identification number entered by the user, as a condition for allowing
access to all allowed functions and for signaling an unlocking signal when
the correlation is correct; and
means responsive to the unlocking signal to permit unlocking of said lock.
2. The electronic lock system of claim 1 further including:
means for storing a lock owner number in each of said locks to identify the
owner of each of said locks and means in each of said card keys for
storing a lock owner number in each of said card keys;
a display on said card key; and
means for displaying information from said lock on said card key display
which should be rightfully known only to the lock owner.
3. An electronic lock system comprising a plurality of locks and a
plurality of card keys, each of said card keys being arranged for opening
any of said locks;
each of said locks and each of said card keys having at least one related
communication port thereon so that when a card key is positioned with
respect to one of said locks, said communication ports are positioned for
communication;
means for storing a lock owner number in each of said locks to identify the
owner of each of said locks;
a register in each said card key for electronic storage therein of a unique
card key identification number;
a register in each said lock for electronic storage therein of a list of
invalid card key identification numbers;
a register in each card key for electronic storage therein of invalid card
key identification numbers;
means for causing said card key identification number register in said lock
to update said invalid card key identification number register in said
card key and for causing said invalid card key identification number
register in said card key to update said invalid card key identification
number register in said lock;
a security number register in said card key and a security number register
in said lock;
means for permitting said security number register in said card key to
advance said security number register in said lock and for erasing the
invalid card key identification number register in said lock when the
security number register in said card key is advanced.
4. The electronic lock system of claim 3 further including:
means for storing a board number in each of said locks to identify the
affiliation of each of said locks and means in each of said card keys for
storing at least one board number in each of said card keys; and
means for comparing board numbers in said card key and in said lock, for
allowing access to all allowed functions and for opening said lock only
when its board number is found in said card key.
5. The electronic lock system of claim 3 further including:
a security number register in said lock and a security number register in
said card key, said security number registers each comprising means for
storing a number in memory and means for incrementally advancing the
number stored in memory.
6. The electronic lock system of claim 3 further including:
a security number register in said lock and a security number register in
said card key, each of said security number registers having successively
indicated security numbers therein;
means for comparing the security number in said security number register in
said card key with said security number register in said lock and
advancing the security number in said lock to correlate correctly to the
security number in said card key when said security number in said lock is
behind said security number in said card key and inhibiting access to said
lock when said security number in said lock is ahead of said security
number in said card key.
7. The electronic lock system of claim 6 wherein:
said security number register comprises a memory for storing numerical
values and said memory can be incremented by a predetermined value when
said security number register memory in said lock is of lower value than
the value in said security number register memory in said card key.
8. The electronic lock system of claim 3 further including:
means for inhibiting access to all functions including opening of said lock
when attempted with a card key whose card key identification number is in
said invalid card key identification number register in said lock.
9. The electronic lock system of claim 8 further including:
an invalid card key identification number memory in said card key and means
for adding to the listing of invalid card key identification numbers in
said card key memory from said lock memory each time said card key is
utilized in a lock.
10. The electronic lock system of claim 9 wherein:
said lock includes a compartment which is openable to open a space by
moving a panel;
an electromagnet in said lock and a pole plate movable against said
electromagnet to be retained thereby, said electromagnet being connected
to said locking circuit;
a latch edge and a hook positioned so that when said hook is engaged on
said latch edge said panel is restrained from moving to a space-open
position, one of said latch and said hook being connected to said pole
plate and the other being connected to said panel;
means on said hook and said latch for thrusting said pole plate against
said electromagnet so that when said pole plate is thrust against said
electromagnet and power is supplied to said electromagnet, said latch and
said hook are held out of latched position so that said panel can open
access to said space.
11. The electronic lock system of claim 10 wherein there is a switch
positioned to be closed when said pole plate is pressed against said
electromagnet so that an electronic means for energizing said
electromagnet at the instant that said switch changes from closed
condition to open condition and to continue said energization for a time
interval thereafter when said electromagnet is only actuated when said
latch and hook are ready for release of said panel.
12. An electronic lock system comprising a plurality of locks and a
plurality of card keys, each of said card keys being arranged for opening
any of said locks, wherein each said lock includes a compartment which is
openable to open a space by moving a panel;
an electromagnet in said lock and a pole plate movable against said
electromagnet to be retainable thereby, said electromagnet being connected
to said locking circuit;
a latch edge and a hook positioned so that when said hook is engaged on
said latch edge said panel is restrained from moving to a space-open
position, one of said latch and said hook being connected to said pole
plate and the other being connected to said panel;
means on said hook and said latch for thrusting said pole plate against
said electromagnet so that when said pole plate is thrust against said
electromagnet and power is supplied to said electromagnet, said latch and
said hook are held out of latched position so that said panel can open
access to said space;
each of said locks and each of said card keys having at least one related
communication port thereon so that when a card key is positioned with
respect to one of said locks, said communication ports are positioned for
communication;
means in each said card key for electronic storage therein of a unique card
key identification number;
means in each said card key for receiving and storing a personal
identification number of a key card user;
an invalid card key identification number register in each said lock and an
invalid card key identification number register in each said card key;
means for updating said invalid card key identification number register in
said lock from said invalid card key identification number register in
said card key when said card key is placed in communication with said
lock;
means for updating said invalid card key identification number register in
said card key from said invalid card key identification number register in
said lock;
means for inhibiting access to all functions including opening of said lock
by a card key when its card key identification number is listed in said
invalid card key identification number register in said lock when in
communication;
a security number register in each said lock and a security number register
in each said card key, each said security number register having
successive security states;
means for advancing said security number register in said lock in one
direction only when said security number register in said card key is
ahead of said security number register in said lock;
means for erasing said invalid card key identification number register when
said security number register is advanced;
means for inhibiting access to all functions including opening of said lock
when said security number register of said lock is advanced beyond said
security number register of said card key;
means for determining the correctness of a correlation between the personal
identification number stored in the card key and the personal
identification number entered by the user and for signaling access to all
functions including an unlocking signal when the correlation is correct;
means responsive to the unlocking signal to permit unlocking of said lock.
13. The electronic lock system of claim 12 wherein there is a switch
positioned to be actuated when said pole plate is pressed against said
electromagnet so that said electromagnet is only actuated when said latch
and hook are ready for release of said panel.
14. An electronic lock system comprising a plurality of locks and a
plurality of card keys, each of said card keys being arranged for opening
any of said locks;
each of said locks and each of said card keys having at least one related
communication port thereon so that when a card key is positioned with
respect to one of said locks, said communication ports are positioned for
communication;
means for storing a lock owner number in each of said locks to identify the
owner of each of said locks;
means in each said card key for electronic storage therein of a unique card
identification number;
means in each said card key for receiving and storing a personal
identification number of a card key user;
means in each of said card keys for storing a lock owner number in each of
said card keys;
means for determining the correctness of a correlation between the personal
identification number stored in the card key and the personal
identification number entered by the user and for signaling an unlocking
signal when the correlation is correct;
means responsive to the unlocking signal to permit unlocking of said lock;
means for comparing lock owner numbers stored in said lock and said card
key to determine correctness of correlation;
a display on said card key;
means for displaying information from the lock on the card key display
which should be rightfully known only to the lock owner;
a security number register in said lock and a security number register in
said card key, said security number registers each comprising means for
storing a number in memory and means for incrementally advancing the
number stored in memory;
an invalid card key identification number memory in said lock and means for
inhibiting opening of said lock when opening is attempted with a card key
whose card key identification number is in said invalid card key
identification number memory in said lock; and
means for erasing said invalid card key identification number memory when
said security number register in said lock is advanced.
15. An electronic lock system comprising:
a plurality of locks, each of said locks having a unique lock
identification number, a lock control circuit, a security number memory
with a plurality of settings and a lock memory connected to actuate said
lock control circuit and a communications port;
a plurality of card keys, each said card key having a unique identification
number, having an input for inputting a personal identification number, a
security number memory having a plurality of settings, a card key
identification number memory and a communications port;
means for selecting one of said security number memory settings in said
lock;
means for selecting one of said security number memory settings in said
card key;
means associated with said lock security number memory and means associated
with said card key security number memory for advancing said lock security
number memory in one direction only to a new setting when the card key
security number memory is in a more advanced state than of the lock;
an invalid card key identification number register in each said lock and an
invalid card key identification number register in each said card key;
means for updating said invalid card key identification number register in
said lock from said invalid card key identification number register in
said card key when said card key is placed in communication with said
lock;
means for updating said invalid card key identification number register in
said card key from said invalid card key identification number register in
said lock when said card key is placed in communication with said lock;
means for inhibiting all functions including opening of said lock by a card
key when said card key identification number is listed in said invalid
card key identification number register in said lock;
a security number register in each said lock and a security number register
in each said card key, each said security number register having a
successive security states;
means for advancing said security number register in said lock in one
direction only when said security number register in said card key is
ahead of said security number register in said lock;
means for erasing said invalid card key identification number register when
said security number register is advanced; and
means for inhibiting all allowed functions including opening of said lock
by a card key when said security number register of said lock is advanced
beyond said security number register of said card key.
16. The electronic lock system of claim 15 wherein a circuit in said lock
and a circuit in said card key each define a security number corresponding
to a memory setting and comparison of selected memory settings is made by
comparing security numbers.
17. The electronic lock system of claim 16 wherein said card key contains a
use memory which stores time and lock identification information therein
with respect to card key usage with any one of said locks.
18. An electronic lock system comprising:
a plurality of locks, each of said locks having a communication port, a
unique lock identification number, a lock control circuit, a security
number memory with a plurality of settings and a lock memory connected to
actuate said lock control circuit;
a plurality of card keys, each said card key having a unique personal
identification number, each said card key having an input for inputting a
personal identification number, a security number memory having a
plurality of settings, a card key identification number memory and a
communications port;
means for selecting one of said security number memory settings in said
lock;
means for selecting one of said security number memory settings in said
card key;
means associated with said lock security number memory and means associated
with said card key security number memory for advancing said lock security
number memory to a new setting in one direction only when the card key
security number memory is in a more advanced state than that of the lock;
an invalid card key identification number register in each said lock and an
invalid card key identification number register in each said card key;
means for updating said invalid card key identification number register in
said lock from said invalid card key identification number register in
said card key when said card key is placed in communication with said
lock;
means for updating said invalid card key identification number register in
said card key from said invalid card key identification number register in
said lock when said card key is placed in communication with said lock;
means for inhibiting access to all functions including opening of said lock
by a card key when said card key identification number is listed in said
invalid card key identification number register in said lock;
a security number register in each said lock and a security number register
in each said card key, each said security number register having
advanceable security states;
means for advancing said security number register in said lock when said
security number register in said card key is ahead of said security number
register in said lock;
means for erasing said invalid card key identification number register when
said security number register is advanced;
means for denying access to all functions including opening of said lock by
a card key when said security number register of said lock is advanced
beyond said security number register of said card key;
an invalid card key identification number register in said lock and means
for inhibiting access to all functions including opening of said lock by a
card key when the card key identification number of said card key is in
said invalid card key identification number register of said lock; and
means for erasing said invalid card key identification number register when
said security number register in said lock is advanced.
19. The electronic lock system of claim 18 further including:
an invalid card key identification number memory in said card key and means
for adding to the listing of invalid card key identification numbers in
said card key memory from said lock memory each time said card key is
utilized in a lock.
20. The electronic lock system of claim 18 further including means for
changing the personal identification number of a card key from a first
personal identification number to a second personal identification number
only when the first personal identification number is entered into said
card key.
21. An electronic lock system comprising a plurality of locks and a
plurality of card keys, each of said card keys being arranged for opening
any of said locks;
each of said locks and each of said card keys having at least one related
communication port thereon so that when a card key is positioned with
respect to one of said locks, said communication ports are positioned for
communication;
a security number register in said lock, said security number register
comprising means for storing a number in memory and means for advancing
the number stored in memory;
a security number register in each said card key, said security number
register in each said card key each comprising means for storing a number
in memory and means for advancing the number stored in memory;
means for determining the correctness of correlation between the security
number stored in the security number register in said lock and said
security number register in said card key and for signalling and unlocking
signal when the correlation is correct;
means responsive to the unlocking signal to permit unlocking of said lock;
and
means for providing the unlocking signal for a limited time when the
security number register in said card key is behind said security number
register in said lock.
22. The electronic lock system of claim 21 further including a card
identification number assigned to each said card key and means in each
said card key for electronic storage therein of the unique card
identification number;
means in each said lock and each said card key for storage therein of
invalid card identification numbers so that when a card having an invalid
card identification number is in communication with a lock, said lock will
not produce an unlocking signal;
means for exchanging invalid card identification numbers between said lock
and said card key even during the limited period when the security number
of said lock is ahead of said security number in said card.
23. The electronic lock system of claim 22 further including means in said
card for incrementing the security number in said lock.
24. The electronic lock system of claim 23 wherein said means for updating
said security number is effective even during the limited period when said
card key has its security number register behind the security number
register in said lock.
25. The electronic lock system of claim 23 further including a programmer
for use with one of said card keys for incrementing said security number
register in said card.
26. The electronic lock system of claim 25 further including a programmer
for use with one of said card keys for listing new invalid card
identification numbers therein for exchange with locks with which said
card key is in communication.
27. An electronic lock system comprising a plurality of locks and a
plurality of card keys, each of said card keys being arranged for opening
any of said locks;
each of said locks and each of said card keys having at least one related
communication port thereon so that when a card key is positioned with
respect to one of said locks, said communication ports are positioned for
communication;
a security number register in said lock, said security number register
comprising means for storing a number in memory and means for
incrementally advancing the number stored in memory;
a security number register in each said card key, said security number
register in each said card key each comprising means for storing a number
in memory and means for incrementally advancing the number stored in
memory;
means for determining the correctness of correlation between the security
number stored in the security number register in said lock and said
security number register in said card key and for allowing access to all
functions including signalling an unlocking signal when the correlation is
correct;
means responsive to the unlocking signal to permit unlocking of said lock;
means for producing the unlocking signal for a limited time when the
security number register in said card key is behind said security number
register in said lock; and
manual input means on each of said card keys, said manual input means being
connected to said security number register for incrementing said security
number register of said card key.
28. An electronic lock system comprising a plurality of locks and a
plurality of card keys, each of said card keys being arranged for opening
any of said locks;
each of said locks and each of said card keys having at least one related
communication port thereon so that when a card key is positioned with
respect to one of said locks, said communication ports are positioned for
communication;
a register in each said card key for electronic storage therein of a unique
card key identification number;
a register in each said lock for electronic storage therein of a list of
invalid card key identification numbers;
a register in each card key for electronic storage therein of invalid card
key identification numbers;
means for causing said invalid card key identification number register in
said lock to update said invalid card key identification number register
in said card key, and for causing said invalid card key identification
number register in said card key to update said invalid card key
identification number register in said lock;
a security number register in said card key and a security number register
in said lock;
means for permitting said security number register in said card key to
advance said security number register in said lock and for erasing the
invalid card key identification number register when the security register
in said card is advanced; and
means for providing access to all allowed functions and an unlocking signal
in said lock for a limited time for card keys in which security number
registers lag behind said security number register in said lock.
29. The electronic lock system of claim 28 further including means for
disabling said card key when the card key identification number is found
in said invalid card key identification number register.
30. An electronic lock system comprising a plurality of locks and a
plurality of card keys, each of said card keys being arranged for opening
any of said locks;
each of said locks and each of said card keys having at least one related
communication port thereon so that when a card key is positioned with
respect to one of said locks, said communication ports are positioned for
communication;
a security number register in each of said locks;
a security number register in each of said card keys;
means in each of said card keys for signaling security number register
advance in said lock with which it is in communication; and
means for providing access to all allowed functions and an unlocking signal
to the lock for a limited time for card keys whose security number
registers lag behind said security number registers in said lock so that
for a limited time a card key having a security number in its register
which is behind the security number register in said lock can provide an
unlock signal in said lock. |
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Claims |
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Description |
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FIELD OF THE INVENTION
This invention is directed to an electronic lock system wherein a card key
is employed with a lock to gain access to a locked space, and particularly
to a key safe system which allows different persons, each with his own
card key and personal identification number, to open the locked space.
BACKGROUND OF THE INVENTION
There are a number of situations in which it is desirable to permit access
to locked space by a plurality of different persons, but provide security
of that access by requiring two separate elements to open the locked
space. This prevents access by someone who has found a lost key, for
example. A room in which medical drugs or valuables are stored, may
require such security of access. Furthermore, it may be desirable to
require a recording of those having access and the time that it occurred.
In real estate operations, in order to permit a number of different sales
persons to have access to various properties for sale, key safes are used.
The key safe is securely attached to the property and has a locked space
therein in which the access device to the property is stored. This access
device may be a key or it may be a card key. When a small real estate
office having few salespersons has exclusive sales rights to several
properties, the problem is not very complicated. Such may be a real estate
office with a limited number of locks and a limited number of
salespersons. A small number of locks permits changing of the locks when a
salesperson terminates with the office. However, such is inconvenient even
with a small office.
Key safes historically have been of the common key type where all users
have an identical key. An improved type of key safe is the two-element
input type where many different keys, each associated with a unique
number, must be used to gain access. The improved type has the additional
advantage of allowing recording of access and remains secure even if keys
are lost. However, with these systems, if salespersons terminate there is
no means of excluding them from the system other than by requiring them to
give up their keys or by changing locks.
It is conventional in modern real estate sales practice for a group of real
estate offices to band together for multiple listing. The group of real
estate offices creates a real estate board which manages the multiple
listing arrangement. Multiple listing means that the salespersons of any
office belonging to the board can have access to any of the properties
listed by the board. The number of key safes then becomes large, and it
becomes very inconvenient to physically go out and change the key safes.
Thus, when one of the salespersons terminates, the security of the key
safe system is compromised unless that salesperson surrenders his/her key.
Also, with such multiple listing systems, one of the offices may withdraw
to create a larger scale compromise of security. In such a case, none of
the salespersons from the withdrawn office would be entitled to access to
the multiple listed properties. In these situations, a larger number of
locks would have to be changed.
Thus, there is need for a system by which key safes can be attached at
property available for sale and the key safes can be updated with new
access information without the need for anyone going to each key safe
specifically for updating its locking system or each key safe being
transported to the board for updating its locking system. Due to the
complexity of the problem, the real estate key safe system is considered
to be a preferred embodiment of the electronic lock system of this
invention, but there are other locked spaces to which an electronic lock
system is also applicable, to enhance their security and reduce the need
for direct security attention to each lock. Once hardware and software
have been created to permit such remote updating, other desirable
features, such as the routine collection of property showing data, become
possible.
SUMMARY OF THE INVENTION
In order to aid in the understanding of this invention, it can be stated in
essentially summary form that it is directed to an electronic lock system
wherein an electronic lock is associated with each of a plurality of
locked spaces and a card key is associated with each of a plurality of
persons having potential access to each locked space. A card key is
activated by having the card holder insert his personal identification
number into the card. The card key is then placed in association with a
lock and data is exchanged between the lock and the card key. When the
lock memory recognizes the card key data as proper, the locked space can
be opened. The card key will normally be activated before placing on the
lock because it is physically easier to do so. The card key remains
"alive" for about 10 seconds. At the Board's option, the card can be so
activated and remain "armed" indefinitely for one opening of a lock to
occur at any future time. The card would then be simply turned on, placed
on the lock, and "OPN" key pressed. The Board can, of course, elect not to
have this convenience option because there is a small security degradation
in having it. It is decided before card distribution and programmed in (or
out) of each card as it is issued. The exchange of data includes updating
of memory in both the lock and the card key so that the card updates the
lock memory as to previously authorized card identification numbers, whose
access is now to be denied, and the lock updates the card key memory so
that it can pass along all invalidated card identification numbers.
When the lock is a key safe, motion of the key safe key compartment causes
momentary closure of a normally open limit switch, which powers up the
electronics for a predetermined brief period and causes thrust of the
latch pole plate against the electromagnet so that, upon release of the
key compartment, if access is authorized, the pole plate is
electromagnetically retained to permit key compartment opening.
It is thus an object and advantage of this invention to provide an
electronic lock system wherein a locked space can be secured and access
obtained thereto by means of a plurality of persons, each having his own
card key and corresponding secret personal identification number (PIN),
which must be entered correctly before the signals necessary for access to
the locked space can be transmitted from the card to the lock and
validated by the lock memory so that access is obtained only by a card key
holder having knowledge of the secret PIN. Provision is made for the value
of the PIN to be changeable as a security precaution. The old PIN must be
used in order to be able to set a new PIN.
It is another object and advantage of this invention to provide an
electronic lock system, particularly useful in connection with a set of
real estate key safes, wherein each of a plurality of unique card keys can
be individually associated with a plurality of unique locks, and the card
key user activates his card key with his secret personal identification
number. The card key user can have access to those locks where the lock
memory validates current acceptance of the card identification number.
It is another object and advantage of this invention to employ a card key
and key safe system wherein a plurality of such card keys and a plurality
of such locks are inter-related to each other, and the card keys and locks
exchange information between their memories so as to update their memories
as to which previously issued card key identification numbers have been
made invalid.
It is another object and advantage of this invention to provide a key safe
wherein the structure is arranged so that a minimum amount of electrical
energy is employed to operate the electronics and to actuate the unlocking
electromagnet so as to maximize battery life. Only the key safe clock
operates continuously. The microprocessor is off, except for a few
milliseconds each minute to update time in the lock memory, or when the
key compartment is pressed.
Other objects and advantages of this invention will become apparent from a
study of the following portion of the specification, the claims and the
attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front-elevational view of a key safe which forms a part of the
electronic lock system of this invention.
FIG. 2 is a side-elevational view thereof, with parts broken away and with
a card in position.
FIG. 3 is an enlarged section, taken generally along the line 3--3 of FIG.
1, showing the key safe key compartment-locking mechanism in the locked
position.
FIG. 4 is a sectional view of the key safe, taken generally along line 4--4
of FIG. 3.
FIG. 5 is a view similar to FIG. 3, but showing the key compartment
manually thrust to the upper position.
FIG. 6 is a view similar to FIG. 5, showing the beginning of release of the
key safe key compartment where the signal switch is opened and showing in
dashed lines the key compartment hook passing the electromagnet-retained
latch.
FIG. 7 is a similar view showing the key safe key compartment toward the
open position.
FIG. 8 is a plan view of the front of a card key.
FIG. 9 is a schematic block diagram drawing of the various electronic and
physical parts of the system and showing the lines by which they interact
with each other.
FIG. 10 is a diagrammatic view of the initial card key programming and
reading system.
FIG. 11 is a diagrammatic view of the initial lock programming system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The two principal portions of the electronic lock system of this invention
are the lock 10, shown in elevation in FIGS. 1 and 2 and the card key 12
shown in front elevation in FIG. 8. These individual portions of the
system interact in a manner to provide a useful locking system which
permits access by those persons who are authorized and denies access by
those persons who are not authorized. Furthermore, the system updates
itself as to the state of authorization of particular card keys (and
thereby particular card key holders) by interchanging data between the
lock and card key when they are associated with each other. Furthermore,
the lock system includes a plurality of locks, which may be at different
locations, and a plurality of card keys, mostly in the possession of
authorized users. The lock 10 is described as key safe, but this is the
preferred embodiment, and the electronic lock system is applicable to
other similar locking and security applications.
Lock 10 has a housing 14 which carries thereon shackle 16. The shackle 16
is sized to fit around the stem of a doorknob, railing or hose spigot so
that the lock 10 may be placed thereon and retained in place, except by
opening the shackle. The shackle is locked in place by any convenient and
conventional lock structure, such as a key or a combination lock.
Combination dials for the shackle are indicated at 13 in FIGS. 1 and 2.
The locking of the shackle is not the particular subject matter of this
invention. The lock housing has a slidable key compartment 18 therein, and
it is access to this key compartment to which this invention is directed.
The key compartment is sized so that, when open, several keys or
door-opening card keys may be inserted therein and the key compartment may
be closed and locked within housing 14 to prevent unauthorized access to
the contents of the key compartment. In real estate usage, an authorized
salesperson opens the key compartment and uses the key or card key therein
to gain access to the real estate property he wishes to show. Thus, only
authorized users should be permitted access.
The criteria by which access is permitted is electronically evaluated.
Accordingly, there are electronic parts in both the card key and the lock,
as shown in FIG. 9. The lock 10 may stay in place in a location away from
convenient maintenance for a considerable length of time. Thus, the
electronics should consume minimal power and the electromagnet for causing
lock opening should consume only minimal energy to maximize battery life.
As compared to a solenoid, the electromagnet/latch mechanism of this
invention consumes very little energy.
Key compartment 18 is a sliding compartment. In FIG. 3, it is shown in its
latched position wherein the bottom end of the key compartment, as seen in
FIGURE 2, is flush with the general bottom surface of the lock housing 14.
From that position, the sliding key compartment 18 can be pressed upward,
which is inward into the lock housing a short distance to the position
shown in FIG. 5. When the locking system permits release of the key
compartment, it can slide downward through the position shown in broken
lines in FIG. 6 to the position shown in FIG. 7. Formed as a part of the
key compartment and extending upward is hook 20, which has a step 22
thereon for engagement against the latch. It is desirable to make a small
undercut on the hook to prevent release of the key compartment when
shocked by impact. Hook 20 has angular cam surface 24 thereon for
thrusting the latch and pole plate 60 toward the electromagnet 44.
Latch spring 26 has a back 28 which is secured to the back wall 30 of the
lock housing 14 by any convenient means, such as rivet 32. The latch
spring 26 is preloaded so that, when riveted in position on the back wall
and when otherwise unengaged, it lies preloaded against the back wall, as
is shown in FIG. 3. The upper part of the latch spring is formed with an
inverted U-shaped structure, including cross member 34 and dependent panel
36. As is seen in FIGS. 5, 6 and 7, the dependent panel has an opening
formed therein by pressing back a section to form ramp 38. The front of
the ramp 38 has an angular face 40 which is at about the same angle as the
cam surface 24, as seen in FIG. 3. The bottom edge of the opening is
defined by latch edge 42. The hook 20 and the latch opening formed by the
depression of the panel are positioned and sized so that, when the latch
spring 26 lies against the back 28 of the lock housing, the latch opening
is positioned to receive the nose on the hook, as seen in FIG. 3. In this
position, step 22 on the key compartment engages against the latch edge 42
so that the key compartment is latched in place. When the key compartment
is open, as seen in FIG. 7, latch spring 26 also lies against the back of
the housing 14.
Electromagnet 44 is carried on mounting plate 46, which is supported from
the back of the housing on posts 48 and 50, see FIG. 4. Electromagnet 44
is cup-shaped to provide an annular outer pole and has a center pole
therein which terminates in rivet head 52, which also retains the cup of
the electromagnet on the mounting plate. The front 54 of the electromagnet
is a planar surface comprising said annular pole and central pole and
forming a magnetic circuit gap for receipt of a pole plate 60. The pole
plate closes the magnetic gap and, therefore, can be securely held when
the electromagnet is energized.
Ears 56 and 58 are turned up on the end of the latch spring beside the
latch opening and beside the dependent panel 36, as seen in FIGS. 3, 4 and
6. Pole plate 60 carries a pivot pin 62 in the back thereof, and the pivot
pin engages in corresponding pivot openings in the ears 56 and 58. In this
way, the pole plate is pivoted on the latch spring. The parts are sized
and positioned so that the pole plate can move against the planar front
surface 54 of the electromagnet. Pivotal movement of the pole plate and a
small amount of twisting of latch back 26 permits perfect alignment of the
pole plate to the electromagnet poles. Resilience between the pole plate
pivot holes in ears 56 and 58 and ramp 38 permits full contact of the pole
plate to the electromagnet poles without excessive rearward loading of the
key compartment.
Normally open contacts 64 are positioned in the path of key compartment 18,
and when the key compartment is pushed upward past its normally latched
position to the position shown in FIG. 5, the contacts are closed,
energizing the key safe electronic module. The contacts are connected
through lines 66 to electromagnet control circuit 69 which is connected to
electromagnet 44 by lin | | |
