Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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1233-261A
HIERARCHICAL SYSTEM OF LOCKS AND KEYS AND
KEY BLANKS THEREFOR
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates generally to
hierarchical systems of locks and keys and, more
particularly, to such hierarchical systems wherein the
locks have distinct key slots including an upper
portion and a lower portion which are disposed at
predetermined relative angular orientations.
Description of Backqround Art
It is known in the art to use masterkeying
techniques to provide a single key slot with means for
forming different keyways so as to differentiate
between different keys in a hierarchical system and
thus increase masterkeying capabilities. For example,
the key 310t may include a ward(s) or similar structure
designed to prevent passage of some keys which are not
intended to operate the lock. Thus, the key slot with
a ward is a ur.ique first keyway and the key slot with a
the ward shifted is a second unique keyway. By
providing the key slot with such structure to form
differenr keyways, only the keys intended to operate a
particular lock can enter that lock's keyway. In
addition, a master key having a blade and a
corresponding section cut therein, e.g. a milled
se~tion, which passes the ward in both unique keyways
permits the master key to enter either of the
keyways.
The use of specially-configured key slots with
corresponding key profiles to provide restricted key
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systems is known in the art. U.S. Patent No. 5,176,015
to Sussina discloses a restricted key system comprising
a chevron-shaped key slot and corresponding key blank.
The blade of the key blank includ~s an upper planar
portion and a lower planar portion joined at an
intermediate portion which forms a horizontal ledge.
The lower planar portion extends at a predetermined
angle from the intermediate portion with respect to a
vertical line extending downward from the upper
portion, which angle may be in the range of
approximately 5-85.
The key disclosed in the Sussina patent provides a
plurality of increased key surfaces (compared to the
prior art) which may be utilized in conjunction with
various key differing techni~les to form different keys
for use in masterkeying systems, which systems are
based on the particular common angular orientation of
all the key slots in a given family. For example, one
or more of the key blade surfaces may be milled so that
the key will pass a ward(s) located in different key
sections. Such a key may be used as a master key
because, in addition to entering the key slots having a
ward(s), the key will also enter other key slots from
the same family which do not have a ward (because the
key slots and the key blade have corresponding angular
orientations, e.g., 10). This permits a large number
of key differs to be generated for a given family of
key slots, i.e., all of the locks having a key slot
with a lower planar portion and an upper planar portion
disposed at a particular predetermined angular
orientation (which corresponds to the angular
orientation of the key slot).
The Sussina patent teaches that the angled keys of
the restricted key system will enter no other key slot
but their own, i.e., the 5 keys fit only the 5 key
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slots, the 10 keys the 10 slots, etc. In addition,
the patent states that the chevron-shaped, proprietary
key slots will block entry of all prior art keys.
Thus, the Sussina patent teaches forming a hierarchical
system of locks within a given family cf key slots,
i.e., each family of key slots having a given
predetermined angular orientation. As discussed above,
Sussina teaches masterkeyiny through the use of
conventional warding techniques combined with the
additional key surfaces provided by the chevron-shaped
key blank. The patent does not discuss the use of a
key which enters different families of key slots, i.e.
key slots having different angulàr orientations.
As such, the number of differs provided by the
wards, etc., and the masterkeying capabilities of the
lock are limited. Additional masterkeying is desirable
and has continually been sought in the art.
Accordingly, there is a need in the art for improved
hierarchical systems of locks and keys and key blanks
therefore.
SU~IARY OF THE INVENTION
The present invention provides a hierarchical
system of locks and keys in which at least two distinct
key slot configurations (or families) are provided, and
wherein key blanks are configured to enter only one of
the first and second families of key slots. The key
slots include an upper portion and a lower portion, and
the lower portion extends away from the upper portion
at a predetermined angle which is the same for all the
key slots in a given family. The angles are different
for each family and are selected so that the lower
portions of the two different key slot configurations
overlap, i.e., when the upper portions thereof are
aligned the lower portions extend therefrom at
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different angles but have a common area of overlap.
The overlap portion defines a third unique key slot
configuration which may be used in an additional lock,
and a third key which corresponds to such configuration
will not only enter the third key slot, but will also
enter the other two key slot configurations (and thus
be a master key with respect to the first and second
families of slots). This feature permits limiting the
access of certain keys within one hierarchical system
while increasing masterkeying capabilities beyond those
of the prior art.
The prior art teaches that 4,096,000,000
theoretical key differs can be obtained for 17,408 key
blank sections. According to such prior art, a first
key slot configuration of the present invention has
4,096,000,000 key differs, and a second key slot
configuration also has 4,096,000,000 key differs.
However, the present invention provides the third
uni~le key slot configuration defined by the overlap of
the first and second key slots, and the third key slot
creates a total of 12,288,000,000 key differs within
the hierarchical system formed by the three key slots.
In addition to the number of key differs that may be
obtained for a given family of key slots as taught in
the prior art, the present invention significantly
increases masterkeying capabilities by combining at
least two separate families of key slots into a
hierarchical system based on the creation of a third
key slot configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
Additional features and advantages of the present
invention will become apparent from the following
detailed description of preferred embodiments taken in
conjunction with the accompanying drawings, wherein:
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FIG. 1 is a sectional view of a lock cylinder with
multiple key slots depicted according to one embodiment
of the present invention;
FIG. 2 is a schematic representation of a
hierarchical system of locks according to the present
invention;
FIG. 3 is a diagram of an additional hierarchical
system according to the present invention;
FIG. 4 is a perspective view of a high security
lock cylinder which may be used to carry out the
present invention;
FIG. 5 is a sectional view of a key or key blank
blade with different cut-out sections indicated in
phantom; and
FIGS. 6A and 6B are, respectively, perspective
views of a removable core cylinder lock and a lock
housing which are provided with anti-picking or
drilling features.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a lock cylinder and key blank
according to the present invention are shown
schematically in longitudinal section and comprise a
lock cylinder 10 which includes a key slot 20 and a
plurality of holes 38 for receiving tumbler pins. The
lock cylinder 10 is ~ounted in a lock housing (not
shown) and may comprise a removable core cylinder lock
if desired. The key slot 20 includes an upper portion
22 and a lower portion 24 which is disposed at a
predetermined angular orientation with respect to upper
portion 22. More particularly, the lower portion 24 of
the key slot is angled with respect to a vertical axis
A passing through the upper portion 22 of the key slot,
such angle being indicated by ~.
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FIG. 1 depicts two distinct key slot
configurations which may be formed by varying the angle
a which the lower portion 24 of the key slots 20 makes
with the axis A. That is, a first key slot
configuration has a width generally corresponding to
reference numeral 28 and includes the hatched portion
34 at the left of FIG. 1 and the cross-hatched area
indicated at refèrence numeral 46. The second key slot
configuration has a width which generally corresponds
to reference numeral 30 and includes the hatched
portion 32 at the right of FIG. 1 and the cross-hatched
area 46. That is, the two key slot configurations 28,
30 include the central hatched portion 46 along with,
respectively, the hatched area 34 and hatched area 32.
lS The two key slots 28, 30 have the lower portions
24 thereof disposed at two different angles relative a
vertical axis A passing through the upper portion 24 of
each key slot (which upper portions correspond to each
other in the embodiment of FIG. 1). Although the lower
portion 24 extends away from the upper portion of each
key slot by different angles ~1 and ~2~ such angles are
selected so that the two key slots 28, 30 partially
overlap. As seen in FIG. 1, the "right side" of the
key slot 28 overlaps with the "left side" of key slot
30, and the area of overlap corresponds to the cross-
hatched area indicated at 46 in FIG. 1. Reference
numeral 46 designates the lower portion of key blank 40
which is positioned within key slot 20 and occupies the
common area of overlap between the two different key
slots. As described below, key blank 40 is a master
key blank.
It is apparent from FIG. I that a key blank with a
lower portion 46 which has a shape corresponding to
that of the lower portion 24 of key slot 28 will not
enter the key slot 30, and vice-versa. However, the
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key blank 40 has a lower portion 46 which will enter
the lower portion of ei~her key slot 28 or key slot 30.
Thus, the key blank 40 may serve as a master key blank
in that it will enter both key slots 28 and 30. As
such, in addition to being able to produce different
key sections for a family of locks having key slots of
a given angle ~, for example by using ward members, the
present invention utilizes at least two different
families of key slots to create a hierarchical system
in which a master key will enter the key slots of each
family (as well as the key slot of a third lock). This
limits the access of certain keys within the
hierarchical system while increasing masterkeying
possibilities compared with prior art systems.
lS In FIG. 1, which shows only a preferred
embodiment, the two key slot configurations 28, 30 have
a lower portion 24 disposed, respectively, at an angle
of 5 and ~2 of 15 relative the axis A. Of course,
other angles ~ may be utilized according to the present
invention. The key blanks which enter the key slots
indicated at 28 and 30 are preferably similar to master
key blank 40 and may include an upper portion 42 and
lower portion 46 connected by an intermediate portion
which comprises a horizontal shelf 43 and a corner
portion 45.
FIG. 2 is a schematic representation of a
hierarchical system of 'ocks which includes a first
lock 110 having a key slot 120 with a lower portion
disposed at an angle ~l relative upper portion 122, and
a second lock 210 having a key slot 220 with a lower
portion disposed at an angle ~2 relative upper portion
222. The angles ~1-2 of the key slots 120, 220 are
selected so as to define an overlap portion which will
permit a master key blanX to enter either key slot 12Q
or 220. The overlap portion not only defines the
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configuration of the lower portion of a master key
blank which will enter either key slot 120 or 220, but
also defines an additional key slot configuration 320
which will receive the master key blank -- which key
slot 320 is shown located in a third lock 310.
However, the key slot 320 will not receive the key
blanks which correspond to the key slots 120, 220 of
locks 110, 2;0. Accordingly, the system depicted in
FIG. 2 could be used with locks 110 and 210 placed on
individual doors with the tenants receiving a key blank
which may be used only with locks in a particular
family of key slots that have the same key slot
confi~lration, for example, the ~key blanks 120 have a
5 angle and enter only the key slots with a 5 angle,
the key blanks 220 have a 15 angie and enter only the
key slots with a 15 angle, etc. However, the master
key could be used to enter all of the locks because its
key blade will enter each family of key slots.
As seen in FIG. 2, the lower portion 324 of key
slot 320 is disposed at an angle ~3 relative the upper
portion 322 of the key slot, which angle ~3 (when
measured from the upper portion 322 to the central axis
of lower portion 324) is between the angles ~1 and ~2 .
However, the lower portion 324 of the key slot 320
preferably has the same shape as the lower portion 46
OL key blank 40 shown in FIG . 1, i.e., a trapezoidal
shape with tapered side walls. Preferably, with
reference to FIG. 1, one of the tapered side walls (the
right wall) of the lower portion 46 of the master key
blank 40 is parallel to the opposite sides forming the
lower portion of key slot 28, whiie the other side wall
(the left wall) of the key blank 40 is parallel to the
opposite sides forming the lower portion of key slot
30. This structure is the preferred embodiment of this
aspect of the invention but, of course, persons
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skilled in the art will appreciate that other
structural variations are possible which provide a
common area to form a third uni~ue key slot/blade.
FIG. 3 is a diagram of a hierarchical system of
locks according to the present invention which includes
a common lock 210' (which may be a relatively low
security level lock) having a key slot 220' configured
to receive a correspondingly configured key 240'. The
key slot 220' has a predetermined angle ~ and may
correspond hierarchically to loc~s 110, 210 shown in
FIG. 2. The system of FIG. 3 includes a high security
lock 310' having a key slot 320' which is configured to
receive a key 340', which key 340' is configured to
also enter the key slot 220' of lock 210'. This can be
achieved, as explained above, by forming the key slot
320' (and master key blade) to correspond to the
overlap portion of two key slot configurations having
different angles ~ (one of which is shown in FIG. 3).
Alternatively, only one family o. locks 210' (i .e., all
the locks having a key slot conf guration with a given
angle ~) may be used, and in this case, a master key
may be formed so as to enter the single key slot
configuration. In either case, -he key 240' does not
enter the key slot 320' of the high security lock 310'.
FIG. 4 depicts a Medeco~ type high security
locking cylinder 400 which incluaes a plug 410 having a
key slot 420, a lock shell 430, a plurality of tumbler
pins 432 whic~ are received in the lock shell in a
known manner, and a fence or side bar 434 which
provides the lock with a double locking feature as is
known in the art. The key slot 420 includes an upper
portion and a lower portion which is angled away from
the upper portion as discussed aDove in connection with
the previous drawing Figures. A key 440 includes a key
blade with an upper portion 442 and a lower portion
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444, the lower portion extending away at an angle so as
to generally correspond to the shape of the key slot
440. FIG. 4 depicts aaditional means for providing
some of the locks in a given system with increased
security as it may be desirable to combine the
restricted key entry provided by the present invention
with conventional high security lock features.
FIG. 5 depicts a prior art key 60 with a
longitudinally-grooved blade portion 62 corresponding
to a particular key slot configuration. The blade 62
may have a portion milled or otherwise removed to as to
pass a ward member positioned in a key slot to prevent
entry of certain keys. One possible milled section is
indicated at reference numeral 64 and another at
reference numeral 66. The portion of the key blade
which is removed depends on the warding present in the
locks of the system; shifting the location of the wards
in the key slot creates new key sections. Typically, a
master key will have section(s) thereof milled out to
permit the key to enter various key slots despite the
presence of ward(s) or other blocking members which
restrict other keys from entering said slots. This
technology may be used in conjunction with the present
invention to further restrict key use within a given
hierarchical system.
FIGS. 6A and 6B depict additional embodiments of
the present invention relating to providing a lock with
further security against tampering or forced entry.
For example, the lock having the third key slot which
is formed by the overlap of the first and second key
slots, as described above, preferably is used in a high
(or higher) security lock because the key blanks which
enter the first two key slots will not enter the third
key slot. The features shown in FIGS. 6A and 6B may
thus be used in such a high security lock to provide
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increased security. Specifically, the removable core
cylinder 500 includes a cylinder face plate 510 and a
key slot 520 with an upper portion 522 and an angled
lower portion 524, which face plate 510 may be formed
-5 of hardened steel to prevent drilling of the lock. The
core may also contain spool or mushroom shaped drivers
512 in openings 514 which provide the lock with
improved pick resistance. Also, the cylinder may
include steel pins 516 in openings 518 which further
~o assist in preventing the lock from being drilled open.
FIG. 6B shows the outer lock housing 600 which
receives a removable core cylinder (such as that shown
in FIG. 6A) in a figure eight-shaped opening 610. A
plurality of security pins 614 are disposed in openings
612 of housing 600 to prevent removal of the core from
the housing, e.g., by drilling the housing to access
the retaining member which secures the removable core
within the housing. Of course, the security features
shown in FIGS. 6A and 6B are but exemplary of various
manners in which the locks according to the present
invention may be further strengthened against tampering
and/or unauthorized attempts to operate the locks.
It is apparent that the present invention provides
increased masterkeying capabilities which have
application in many different environments. For
example, the inventive keys and key slots described
above could be used in any type of lock or locking
cylinder. One benefit of the invention is the
expar.dability it offers with respect to masterkeying
options, plus the ability to restrict entry of
particular keys to a limited number of key slots within
a system. A manufacturer can offer an institution the
long-term benefits of such expandability as the
institution works to retrofit the existing cylinders of
the institution in logical increments. Of course, due
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. ~
to monetary, time or other constraints, an institution
may not immediately implement a complete hierarchy.
However, the present invention permits the institution
to expand in increments by adding key slots according
to the present invention in order to achieve the
desired hierarchical system.
Other features and advantages of the present
invention will readily occur to those skilled in the
art, as will many modifications and alteraticns in the
preferred embodiments of the invention described
herein, all of which may be achieved without departing
from the spirit and the scope of the invention as
defined by the appended claims.
