Note: Descriptions are shown in the official language in which they were submitted.
. - . 219675
REMOTELY-OPER_~.TED SELF-CONTAINED
ELECTRONIC LOCK SECURITY SYSTEM ASSEMBLY
Field of the Invention
The preseTt invention relates generally to locks, and
mere particularly to an electronic lock which is remotely
operated either optically or by radio transmission and
w=ich is sized, arranged and configured to be utilized with
a conventional door hardware lock mechanism.
.5 BACKGROUND OF THE INVENTION
Since the advent of modern semiconductor circuits,
mcst notably the microprocessor, efforts have been madA to
design an electronic door lock which provides a secure,
"pick-proof" lock that incorporates the advantages offered
20 by a microprocessor. Several such attempts at designing
electronic locks are described in U.S. patents 4,573,046;
4,964,023 and 4,031,434. Each of the structures described
in the foregoing patents suffers from a common drawback;
they cannot be directly utilized within the structures of
25 existing conventional doorlatch locks. Such prior art
electronic lock struc~ures generally require new locking
hc:rdware to be installed anc additional holes to be bored
2196750
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through the door and into the door jamb itself. For
example, U.S. patent 4,573,046, issued to Pinnow, generally
discloses an electronic transmitter/receiver locking system
wherein the transmitter is preferably located in a watch
worn on the user's wrist. The reference does not describe,
in other than a conceptual manner, that apparatus which is
responsive to a signal receiver located in the door, that
would physically actuate the lock mechanism. However, the
reference clearly suggests modifying the conventional
doorlatch lock hardware so as to implement the locking
function. Besides the lack of compatibility with existing
door locks, such prior art electronic lock designs suffer
other shortcomings.
U.S. patent 4,964,023, issued to Nishizawa et al.
generally discloses an illuminated key wherein the emitted
light can be modulated to perform an additional keying
function. Presumably, frequency shift keying modulation
(i.e., FSK modulatior_) is utilized, which is easy to
duplicate, thereby significantly reducing the security
provided by such locking mechanism. Duplication of the FSK
modulation "key" may be accomplished, for example, by using
a "universal" TV/VCR remote control which has a "learning"
function. Duplication can be achieved by simply placing
the original "key" in proximity with the "universal"
controller and transmitting the key's optical information
directly into the controller's sensor.
U.S. patent 4,031,434, issued to Perron et al.
generally discloses an inductively coupled electronic lock
that uses a binary coded signal. The key transmits an FSK
signal encoded with a preprogrammed code by magnetic
induction to a lock unit. The lock unit processes the
signal from the key and activates a motor that moves a
deadbolt. The power source for both the key and the lock
unit is contained in the key. This type of locking device
is extremely sensitive to noise and requires fairly close
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operative proximity between the "transmitter" and the
"receiver."
U.S. patents 4,770,012 issued to Johansson et al., and
4,802,353 issued to Corder et al. disclose relatively
complicated combination type electronic door locks that are
partially powered by built-in batteries. The exterior
handles of these locks are used to receive user generated
entrance codes in a manner similar to mechanical
combination locks and use relatively primitive programming
schemes. Such lock structures do not use the conventional
style doorlatch lock structure but are switched between
locked and unlocked states by means of an internal
electromagnetic solenoid which retracts an internal pin
that allows rotation of the exterior handle and opening of
the door. The 4,802,353 lock also provides for a
mechanical key override for the electronic lock structure
and can be used with an infrared communication link to
activate a remotely located deadbolt lock, of the type
described in U.S. patent 4,854,143. In each of the locks
described in these patents, the energy for actually moving
the lock latch relative to the door strike plate is
provided by the user.
The concept of using an electromagnetic locking device
such as disclosed in the above three patents has a number
of drawbacks. First, such devices require substantial
electrical power since the solenoid electromagnets must
remain energized in order to keep the locks in their
unlocked states. Accordingly, battery replacement is
frequent. For example, patent 4,770,012 discloses that the
lock battery lasts through roughly 9,000 locking
operations, which at a normal door usage rate of 30
operations a day, would be less than a year. Patent
4,802,353 discloses that the battery lasts 180 days under
the same conditions. Second, such electromagnetic devices
are also extremely slow. The deadbolt electromagnet
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disclosed in patent 4,854,143 requires 8 seconds and 4
seconds respectively to switch to the unlocked and locked
states. The door electromagnet disclosed in patent
4,802,353 requires four seconds to switch to the unlocked
state. Third, the electromagnetic devices which are
selected for this application are designed to operate at
low currents and cannot resist strong forces along their
axes of motion. This means that they cannot be loaded by
stiff springs and can be easily tampered with by the
application of moderate external magnetic fields. Fourth,
in addition to the length of time taken to operate the
solenoid, additional time (at least 8 seconds) is required
to enter a correct combination code, making the total
elapsed time to open a door on the order of 16 seconds.
This is much longer than the time required to open a door
with a conventional key-operated lock mechanism.
Further disadvantages of the above described
electronic combination lock systems are that the entrance
code may be visibly detected by others, disabled persons
(e.g., blind people) cannot typically use such locks, and
those with mechanical overrides features can generally be
picked. Also compared to conventional door lock
configurations, the above-described combination locks
generally require new manufacturing and tooling procedures
(as compared to those required for conventional doorlatch
locks) and must be partly constructed from nonferrous
materials in the vicinity of the electromagnetic device,
which limits production options.
What is notably lacking in electronic lock structures
heretofore known in the prior art is a simple, "pick-proof"
low power lock configuration that is compatible with the
internal mechanical locking mechanisms of universally used
conventional key-operated doorlatch locks. Such an
electronic door lock design would be compatibly usable
with, and could readily be designed by lock manufacturers
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into, existing doorlatch lock structures with a minimum of
engineering or production tooling effort or cost.
Virtually all existing conventional mechanical lock
structures use the rotational motion of a mechanical key
about the axis of the key acceptor cylinder to move a
locking member. The rotational motion of the key is either
directly used to rotate a locking member or is immediately
translated into linear motion of a locking member which
moves generally along the axis of the key acceptor
cylinder. Such simplicity and effectiveness of the
conventional mechanical doorlatch locks has not been
heretofore duplicated by the complicated, high power
consuming or ineffective prior art electronic lock
structures.
The present invention addresses the shortcomings of
prior art electronic locking structures by using
sophisticated low power electronic components to directly
replace the mechanical key and key accepting lock cylinder
portions of conventional mechanical doorlatch locks while
retaining the internal mechanics of such locks for
performing the actual door locking functions. Such
electronic lock hardware which is designed for
compatibility with existing conventional doorlatch locks
allows manufacturers' investments in current door lock
manufacturing facilities to be retained and takes advantage
of state-of-the-art microprocessor-based electronics to
control plural lock functions including sophisticated
entrance codes, record keeping of authorized entrances,
etc.
SUMMARY OF THE INVENTION
The present invention provides a simple, relatively
inexpensive and yet reliable apparatus and method for
actuating a locking mechanism for use in a door and the
like. The apparatus is designed and preferably sized and
configured to take advantage of existing conventional
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doorlatch lock hardware. For example, in one embodiment of
the invention the mechanical "locking" portion of the
apparatus and an optical or radio frequency sensor is
preferably constructed so as to be installable within the
exterior handle of a conventional door handle, while the
interior handle is equipped with a battery and an
electronic control device. With the exception of the key
acceptor cylinder and modification of the door handle
knobs, all of the remaining components of previously known
conventional doorlatch locks, including the latch,
mechanical locking elements located within the bore of the
door and the strike plate can be utilized in the same
manner as heretofore known in the art. In another
embodiment of the invention, the mechanical locking
apparatus, the battery and the control electronics are all
located within the interior handle portions or within the
escutcheon or rose portion of the door hardware assembly
and only the antenna or sensor portions of the apparatus
are located in the outer handle portion of the assembly.
In general, the locking apparatus of the invention
comprises a remote hand held controller (HHC) which
includes a miniature optical transmitter or radio frequency
transmitter/receiver; an electronic door lock (EDL) which
includes an optical sensor or radio frequency
transmitter/receiver placed internal to that area to be
secured by the EDL; a processor control circuit connected
to the sensor, and an electromechanical device for
actuating the mechanical locking elements of the EDL. The
apparatus may also include an optional keypad which is a
remotely located stationary device that will communicate
with the EDL in manner similar to the HHC. The apparatus
of the present invention may further include an electronic
programmer (EDLP) for the EDL, HHC and keypad which is used
to input desired entrance codes and to control other
functions of the HHC, keypad and the EDL. Preferably,
WO 96/41486 219 6 7 5 0 PCT/US96/07722
communication between the HHC or keypad and EDL (and
between the EDLP and the HHC, keypad or EDL) is two-way,
however, single way communication between the HHC or keypad
and EDL is possible, as described below.
Generally, upon operator initiation, the transmitter
in the HHC or keypad generates a signal which is received
by the sensor or receiver in the EDL. The signal is
processed by the processor, which compares the signal with
predetermined stored signals to determine whether the
received signal constitutes a valid lock actuating
sequence. In the event that the sequence is determined to
be valid, the processor actuates an electromechanical
device (such as a DC motor or the like) to activate the
conventional locking rod of a doorlatch lock. The user
then is able to turn the door handle in a normal manner.
As those skilled in the art can appreciate, the user
supplies the majority of the energy to open the door. As a
result, the electromechanical device need only generate
enough torque to move the locking rod or turn bar (as those
terms are understood in the art) a fraction of a revolution
and can be sized small enough to reside within the handle
portion of the door hardware. In the event that the
received signal sequence is determined to be an invalid
signal, the processor resets to receive a second signal and
the process is repeated. After a predetermined number of
invalid signals are received, the system disables itself
for a predetermined time period in order to discourage a
concerted attempt to methodically try each possible code
combination (e. g., through use of a computer).
The present invention also preferably provides for
high-security two-way communication between the EDL and HHC
or keypad, a limited-access procedure based on "master" and
"submaster" key concepts, and implementation by means of a
miniature electromechanical device which requires minimal
electrical power.
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Another feature of the present invention is that the
lock cannot be "picked" because there is no mechanical lock
cylinder and because an encryption scheme and a spread
spectrum communication (SSC) technique are used.
As a consequence of the advantages and features of the
present invention, an electronic lock apparatus constructed
according to the principles of this invention can be
readily implemented in virtually any conventional
mechanical door hardware lock currently available on the
market with minimal modifications of production procedures.
Therefore, according to one aspect of the invention,
there is provided an electronic lock apparatus for a door,
comprising: (a) a strike plate; (b) a latch cooperatively
engageable with said strike plate and movable along a
latching axis between engaged and disengaged positions;
(c) mechanical locking means, operatively connected with
said latch, for selectively preventing movement of said
latch between said engaged and disengaged positions, said
locking means requiring a primary motive force acting
coincidentally along or about a locking axis, said locking
axis being substantially perpendicular to said latching
axis; (d) at least two oppositely disposed knobs, said
knobs being arranged and configured to rotate about said
locking axis, for actuating said latch between said engaged
and disengaged positions, wherein a user provides the force
to actuate said latch; (e) knob connecting means,
substantially disposed between said knobs, through the
door, for connecting said knobs to said latch; (f)
electromechanical means, operatively connected to said
mechanical locking means, for providing the primary motive
force to said locking means; and (g) electronic control
means, responsive to an encoded received over the air
signal, for selectively energizing said electromechanical
means, wherein said electromechanical means provides force
only along or about the locking axis, wherein said
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electromechanical means and electronic control means are
located entirely within said knobs and said knob connecting
means, thereby sealing and protecting said
electromechanical means and electronic control means from
being accessed by an unauthorized user.
According to another aspect of the invention, there is
provided an apparatus as recited above, wherein said
encoded received signal includes a first set of encoded
signals and a second set of encoded signals, wherein both
of said first and second sets of encoded signals must be
determined to be valid by said electronic control means
prior to energizing said electromechanical means.
A further aspect of the invention provides for an
electronic lock system, comprising: (a) key means for
generating a signal; (b) receiver means for receiving said
signals; (c) a lock mechanism, said lock mechanism being
engaged and disengaged by longitudinal movement of a
locking member between an engaged position and a disengaged
position, said engaged and disengaged positions being
defined at predetermined longitudinal positions along the
longitudinal axis of said locking member; (d) processor
means, cooperatively connected to said receiver means, for
comparing said received signal with a stored reference
signal, for generating an actuation signal if said received
signal is determined to be equivalent to said reference
signal, and for receiving a deactivate signal to terminate
said actuation signal; (e) primary mover means, operatively
connected to said processor means and including a shaft
cooperatively rotatably connected to said locking member,
for longitudinally moving said locking member along said
axis in response to said actuation signal, whereby only the
-longitudinal movement of said locking member is utilized to
lock and unlock said lock mechanism; and (f) lock mechanism
detection means, operatively connected to said primary
mover means, for providing said deactivate signal to said
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processor means when said lock mechanism has been
longitudinally moved to said engaged or disengaged
positions, wherein said processor means receives
confirmation that said lock mechanism has actually
S longitudinally moved between said engaged or disengaged
positions.
According to still another aspect of the present
invention, there is provided an electronic lock apparatus,
of with no mechanical key access for a door, comprising:
(a) a strike plate; (b) a latch cooperatively engageable
with said strike plate and movable along a latching axis
between engaged and disengaged positions; (c) mechanical
locking means, operatively connected with said latch, for
selectively preventing movement of said latch between said
engaged and disengaged positions, said locking means
requiring a primary motive force acting coincidentally
along or about a locking axis, said locking axis being
substantially perpendicular to said latching axis; (d) at
least two oppositely disposed knobs, said knobs being
arranged and configured to rotate about said locking axis,
for actuating said latch between said engaged and
disengaged positions, wherein a user provides the force to
actuate said latch; (e) knob connecting means,
substantially disposed between said knobs and through the
door, for connecting said knobs to said latch; (f) at least
one rose or escutcheon member cooperatively mounted by said
knob connecting means adjacent at least one of said knobs;
(g) electromechanical means, operatively connected to said
mechanical locking means, for providing the primary motive
force to said locking means; and (h) electronic control
means, responsive to an encoded received over the air
signal, for selectively energizing said electromechanical
means, wherein said electromechanical means provides force
only along or about the locking axis, and wherein said
electromechanical means and electronic control means are
WO 96/41486 219 6 7 5 0 pC.l.~s96/07722
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located entirely within said knobs, said rose or escutcheon
member and said knob connecting means, thereby sealing and
protecting said electromechanical means and electronic
control means from being accessed by an unauthorized user.
These and other advantages and features which
characterize the present invention are pointed out with
particularity in the claims annexed hereto and forming a
further part hereof. However, for a better understanding
of the invention, its advantages and objects attained by
its use, reference should be made to the Drawing which
forms a further part hereof and to the accompanying
descriptive matter, in which there is described a preferred
embodiment of the present invention.
BRIEF DESCRIPTION OF THE DRAWING
Referring to the Drawing wherein like parts are
referenced by like numerals throughout the several views:
Fig. 1 is a view of a conventionally styled doorlatch
illustrated as installed in a door, which incorporates an
electronic lock constructed according to the principles of
the present invention;
Fig. 2 is a perspective exploded view of a first
embodiment of the electronic doorlatch lock of Fig. 1;
Fig. 3 is an enlarged cross sectional view of the
switching contacts and coupling (with the DC motor 21 and
gearhead 22 shown in phantom) of the doorlatch lock of Fig.
2 taken through line 3-3 of Fig. 4;
Fig. 3A is an enlarged cross-sectional view of the
switching contacts and coupling (with the rotation thereof
shown in phantom) taken through line 3A-3A of Fig. 3.
Fig. 4 is a cross-sectional view of the exterior door
handle portion of the doorlatch lock of Fig. 1, generally
taken along line 4-4 of Fig. 1;
Fig. 5 is an enlarged exploded perspective view
illustrating the mechanical locking mechanism portion of
the doorlatch lock of Fig. 2;
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Fig. 6 is a functional block diagram representation of
the hand held controller portion (HHC) of the doorlatch
lock of Fig. 2;
Fig. 7 is a functional block diagram representation of
the electronic door lock (EDL) portion of the doorlatch
lock of Fig. 2;
Fig. 8 is a functional block diagram representation of
the electronic programmer portion (EDLP) of the doorlatch
lock of Fig. 2;
Fig. 9 is a diagrammatic illustration of the entrance
coding scheme of a group of EDLs of Fig. 7;
Fig. 10 is an illustration of a preferred
communication timing diagram utilized by an HHC and an EDL
of Figs. 6 and 7;
Fig. 11 is a functional block diagram of block 409 and
509 of Figs. 6 and 7;
Fig. 12 is a logic block diagram illustrating computer
program operation of block 505 of Fig. 7;
Fig. 13 is a logic block diagram illustrating computer
program operation of block 605 of Fig. 8;
Fig. 14 is a cross-sectional view of an interior door
handle portion of an alternate embodiment of the door
hardware of Fig. 1;
Fig. 15 is a partial perspective exploded view
illustrating the mechanical locking mechanism portion of
the door hardware of Fig. 14;
Fig. 16 is an enlarged partial perspective exploded
view of the locking portions of the door hardware or Figs.
14 and 15;
Fig. 17 is an enlarged perspective assembly view of a
portion of the door hardware lock components of Fig. 16,
illustrating the movable locking components positioned in a
locked mode; and
Fig. 18 is an enlarged perspective assembly view of
the door hardware lock components of Fig. 16, illustrating
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the movable locking components positioned in an unlocked
mode.
Detailed Description
The principles of the invention apply particularly
well to utilization in a lock of.the type used to secure a
door in its closed position. A preferred application for
this invention is in the adaptation of conventional
mechanical (i.e., physical key-operated) doorlatch locks to
electronic, keyless locks. Such preferred application,
however, is typical of only one of the innumerable types of
applications in which the principles of the present
invention may be employed. For example, the principles of
this invention also apply to deadbolt locks, window locks,
file cabinet locks and the like.
A preferred embodiment of the electrically related
portion of the invention includes electronic door lock
circuitry which is configured, as hereinafter described in
more detail, for mounting within the hollow recess portions
of the door handles, under the rose or escutcheon plate
members and within other internal operative portions of a
door hardware structure. For ease of description, this
circuitry will hereinafter be referred to simply as the
"EDL." The EDL generally includes an optical sensor or
radio frequency transmitter/receiver having an antenna
generally mounted in the externally facing doorknob, a
microprocessor controller connected to receive signals from
the sensor or to communicate with an rf interface network,
and an electromechanical device (such as a DC stepper
motor) operatively controlled by the microprocessor
controller and connected to physically actuate the door
hardware locking rod. Also included in the electronically
related portion of the invention is a high-efficiency
battery for powering the EDL circuitry.
The EDL circuitry communicates with a remote hand held
controller (i.e., a handheld remote key) and with an
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optional remote stationary keypad using a low-power two-way
optical or radio frequency transmitter/receiver. For ease
of description, this hand held controller will hereafter be
referred to as an "HHC". Thus, the need for a dedicated
physical key is eliminated, and as will become apparent
upon review of the disclosure herein, lock security is
substantially improved. As noted above, the present
invention is preferably installed/implemented within
existing lock hardware (or constructed to resemble/match
existing lock hardware) so that modification of existing
lock hardware dimensions is unnecessary. As a result,
implementation of products in accordance with the invention
requires minimal modification of current procedures for the
production and installation of door locks.
The invention also optionally includes an electronic
programmer (hereinafter simply referred to as an "EDLP")
for programming the HHC, keypad and EDL for desired
entrance codes and to control other functions of the HHC,
keypad and EDL.
Referring now to the figures, there is generally shown
at 20 in Fig. 1 a door hardware lock apparatus as
operatively mounted in a door 19. The door hardware 20 as
will be referred to herein is constructed in a
"conventional" configuration well known in the art, having
interior and exterior handles 25 and 30 respectively which
are cooperatively connected through linkage means within
the door 19 to operatively move and lock a latch member 31.
The latch member 31 engages a strike plate 33 (best seen in
Fig. 2) in an associated door frame (not shown) to secure
or release the door 19 for pivotal motion within the door
frame in a manner well known in the art. Although several
-embodiments thereof will be herein described, the internal
linkage means of the doorlatch 20 that connects the handles
25 and 30 may be of varied configurations as will be
appreciated by those skilled in the art. Since the details
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of construction and operation of such varied configurations
of conventional doorlatch mechanisms are not relevant to an
understanding of the principles of this invention, they
will not be detailed herein except to provide a general
overview thereof and to the extent that an understanding of
the mechanical locking portions thereof may be necessary.
Such door hardware structures are commonly found in
numerous patents, the marketplace, and on most doors and
can be directly examined if more detailed information
thereon is desired.
An example of the linkage mechanism of a first
embodiment of a conventional door hardware locking
apparatus which has been modified to incorporate the
principles of this invention is illustrated in Fig. 2. For
convenience in describing the present invention, the remote
HHC circuitry and the EDL components which reside in the
door hardware 20 will collectively be referred to as the
"electronic lock". Referring to Fig. 2, an electronics
module 500 containing those electrical components of the
EDL (functionally illustrated in Fig. 7) is sized and
configured for mounting in the first embodiment within the
inside handle 25 of the door hardware 20. As is
illustrated in the Figures, handles 25 and 30 are standard
hollow knobs which allow the EDL electronics 500, motor 21,
etc. to be located entirely within the knobs, within the
associated internal hollow portions of the door hardware,
and under the inside rose or escutcheon plate members. An
alternate placement of the electronics module 500 under the
rose 53 portion of the door hardware, is illustrated at
500' in Fig. 2. The interior handle portion of the door
hardware 20 includes a mounting bracket 50 that is fixedly
secured from movement relative to the door 19 through a
bore in the door 19 to a corresponding mounting bracket 30a
for the external handle portion. A hollow cylindrical
shaft 26 is rotatably mounted to the bracket 50 for
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rotation under spring tension from spring 52 about axis 18.
When the door hardware 20 is mounted to the door 19 the
shaft 26 extends through the cover plate 53. The inner
door handle 25 is detachably secured in a manner well known
in the art, to the shaft 26 such.that the shaft can be
rotated against bias of the spring 52 by turning movement
of the handle 25 about the axis 18.
In the first embodiment, the electronics module 500
containing the electrical circuitry, interconnections,
circuit boards, etc., to configure the EDL functions of
Fig. 7 is appropriately packaged between inner and outer
cylindrical mounting tubes 27a and 27b respectively. The
inner mounting tube 27a is sized to coaxially overlie and
to be frictionally or otherwise secured to the shaft 26, as
illustrated in Fig. 2. A high efficiency cylindrical
battery pack 28 is sized for mounting within the
cylindrical shaft 26 and has an appropriate voltage for
energizing the electric components.of the EDL. The battery
terminals are appropriately connected (not illustrated) to
operatively power all electrical components of the EDL that
are housed within the doorlatch 20. In the preferred
embodiment, the end cap 54 of handle 25 is detachable to
provide access to the battery 28 and electronic module 500
circuits housed within the handle 25. Preferably, the end
cap 54 also contains a centrally located switch, generally
illustrated at 29a, and one or two light emitting diode
indicators 29b and/or a visual liquid crystal display
(appropriately connected to the electronic module 500) for
permitting manual lock activation from the inside handle 25
side of the door 19. The indicators 29b provide a visual
indication of the locked status of the electronic lock at
-any point in time and can be used to provide user
information during the "program mode" of the apparatus.
Alternatively, the lock status indicator may be mechanical
so as to conserve battery life and be activated by the DC
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motor from one state to another as those skilled in the art
will appreciate.
That portion of the doorlatch lock that faces the
"outside" of the door is illustrated in Figs. 2 and 4.
Referring thereto, the stationary outer mounting bracket
30a has a hollow cylindrical shaft 30b mounted for rotation
therein about the axis 18 in manner similar to that of
bracket 50 and shaft 26. When mounted to the door 19, the
shaft 30b extends through an external cover plate 70. The
outer door handle 30 is secured to the shaft 30b, such that
shaft 30b rotates with movement of the handle 30 and such
that the handle 30 cannot be detached from the shaft 30b
from the outside of the door when the door is closed, all
as is well known in the art. The shaft 30b is connected to
an outer retainer housing member 30c that rotates with the
shaft 30b. An inner housing retainer member 30d is
operatively connected for rotation with the inner housing
retainer member 30c. The mechanical locking members of the
door hardware assembly are housed between the housing
retainer plate members 30c and 30d as will be described in
more detail hereinafter. An extension 30f of the inner
housing retainer member 30d longitudinally extends along
the axis 18 toward the inner handle assembly and forms a
coupling rod between the shafts 26 and 30b and their
respective handles 25 and 30. The shaft 26 terminates at
its inner end at a retaining plate (not illustrated) but
located for rotation adjacent the inner surface of the
mounting bracket 50. The retaining plate has an axially
aligned aperture formed therethrough which slidably
matingly engages the coupling rod 30f when the door
hardware 20 is mounted to the door 19 such that the shafts
26 and 30b rotatably move together about the axis 18 as
constrained by the coupling rod 30f. The coupling rod 30f
also passes through a keyed aperture in the latch actuating
assembly generally designated at 36. The latch actuating
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assembly 36 operates in a manner well known in the art to
longitudinally move the latch member 31 relative to the
mounting plate 32 against a spring bias tending to keep the
latch 31 in an extended position, in response to rotational
movement of the coupling rod 30f.within the keyed aperture
of the latch actuating assembly 36.
Referring to Fig. 2, a DC motor assembly generally
designated at 21 is mounted within the cylindrical shaft
30b. The motor assembly includes a motor mounting housing
21a which secures the assembly to the shaft 30b, a DC motor
21, a gear reducer 22, a switch contactor plate 57, an
electrical leaf contact 58 (best seen in Fig. 3) forming a
sliding contact with the switch contactor plate 57, and a
coupling member 24. The coupling member 24 is secured to
the shaft 59 of the motor 21/gearhead 22 by means of a set
screw 60 such that the leaf spring contact 58 that is
secured to the coupling member 24 is positioned at a
desired rotational angle relative to the switch contactor
plate 57. The contactor plate 57 has a pair of angularly
spaced contacts 57' that are selectively engaged by the
leaf spring contact 58 as the motor shaft turns the
coupling 24. The contacts 57' and the leaf spring contact
58 combine to form a single pole switch for energizing the
DC motor 21. The outer case of the motor is connected to
ground potential. That surface of the coupling 24 that
faces away from the DC motor 21 defines a slot which
matingly secures one end of a locking rod 23. Locking rod
23 axially extends from the coupling 24 through a cam 223
located in the locking mechanism chamber defined by the
retaining plates 30c and 30d. The electrical energization
of the motor 21 from the battery 28 is performed in a well
known manner using wires (illustrated diagrammatically in
Fig. 7) .
Referring to Fig. 5, the shaft member 30b extends
through a keyed annular shoulder of the outer housing 30a.
_. WO 96/41486 219 6 7 5 0 PCT/US96/07722
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The shaft 30b has a pair of longitudinally extending slots
224 that align with a pair of keyed slots 222 in the
shoulder 225. The cam 223 has a pair of cam surfaces that
cooperatively address the aligned slots and move a pair of
steel balls 221 into and out of the aligned slots as the
cam 223 is rotated by the locking rod 23, as will be
described in more detail hereinafter.
The outer handle 30 preferably has an aperture formed
therethrough, sized and configured to admit a sensor or
antenna 510 which receives radio frequency or optical
signals from the HHC. It will be appreciated that sensor
or antenna functions can also be implemented in the inside
handle portions of the lock apparatus. Sensor 510 is
operatively connected to the electronics module 500 and
appropriately connected within the outer handle 30 so as to
receive the signals entering the handle aperture. Sensor
510 is either ~an optical (e.g. , infrared (IR) ) or radio
frequency (RF) sensor or antenna, best illustrated in Fig.
2.
As those skilled in the art will recognize, when the
locking mechanism is in the unlocked state, the lock is
actuated by rotation of internal and external handles 25,
30, whereby rotation of either handle turns shafts 26 and
30b, respectively, which retracts the doorlatch 31 to a
position within plate 32. This action releases the
doorlatch 31 from the strike plate 33 thereby allowing the
door 19 to be opened.
As noted above, locking mechanisms are generally well
known in the art and so will not be described in additional
detail herein. Those wishing a more thorough background on
such devices may refer to U.S. Patent Nos. 2,669,474;
4,672,829 or 5,004,278. In the first preferred embodiment,
a lock mechanism manufactured by Master Lock of Milwaukee,
Wisconsin, having a designation Model No. 131 is utilized.
Briefly, the lock is physically switched from the unlocked
WO 96/41486 219 6 7 5 0 PCT/US96/07722
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to the locked state by the two steel balls 221 when they
are positioned by cam 223 to ride within the annular
channel 222 as shown in Fig. 5. When the balls 221 are
positioned in channel 222, they are positioned through
slots 224 of the sleeve 30b to prevent rotational motion of
sleeve 30b. When the balls are moved out of the channel
222 by cam 223, the lock is switched from a locked to an
unlocked state. Cam 223 is operatively rotated by the
locking rod 23. The lock is switched from the locked to
the unlocked state and vice-versa whenever the locking rod
23 and the cam 223 are rotated approximately a quarter of a
turn in either the clockwise or counterclockwise directions
by the motor. A pair of limit switches are preferably used
to sense the quarter turn limits of rotational motion and
to de-energize the motor to conserve power when the full
quarter turn rotation has been achieved. In the locked
state the sleeve 30b is prevented from rotating relative to
the outer housing 30a. The handle 30 is thereby prevented
from turning, keeping the doorlatch 31 from retracting.
Most lock mechanisms have an axis of rotation which is
defined as the axis around which torque is applied to cause
the latch to open the door (i.e., motion about the axis of
the key acceptor cylinder). The mechanism which blocks the
rotation in the preferred lockset rides on a cam which
turns about the axis, while others very typically utilize
other blocking means based on rotation about or along the
axis. Those skilled in the art will therefore appreciate
that mechanical motion provided by a physical key in
conventional mechanical doorlatch locks also acts about the
lock axis. The DC motor of the preferred embodiment is
configured to act about the same lock axis as that of the
-key accept or cylinder that it replaces. The shaft of the
motor does not introduce any movement which is not about
the lock axis. Further, actuation of the DC motor assembly
21 (i.e., the electromechanical device which rotates the
WO 96/41486 219 6 7 5 0 PCT/US96/07722
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locking rod 23) requires very little torque or energy to
lock or unlock the door via this method. It should be
understood that other locking mechanisms (e. g., the lock
manufactured by Master Lock Company of Milwaukee, Wisconsin
having the designation S.O. 3211X3 ADJ.B.S.) uses a motion
along the lock axis. An embodiment of the invention that
utilizes such a longitudinal locking motion along the lock
axis will be hereinafter described with respect to a second
embodiment of the invention. Those skilled in the art will
appreciate that the electromechanical device might provide
this motion along the axis rather than.about the axis. The
lock axis of the preferred embodiment is illustrated by the
line denoted by 18 in Fig. 2.
Next, in order to better understand the EDL and HHC
and the method of signaling therebetween, a discussion of
the electrical components will be deferred pending a
general discussion of the operation of the electronic lock.
General Operation
Referring next to Figs. 2, 6 and 7 a functional block
diagram of the circuitry 400 of a preferred handheld
(preferably battery operated) controller. (HHC 400) which
is capable of a two-way communication with the lock without
mechanical contact is illustrated. The two-way
communication is preferably accomplished using either
infrared (IR) light or radio waves (RF). Alternatively,
another means of inexpensive one-way optical communication
may be accomplished with pattern recognition (e. g.,
"barcode" technology) and will be further discussed below.
The HHC 400 contains a circuit which transmits on command
(by pressing either a "lock" or an "unlock" button on the
HHC, as depicted at 402 and 403 respectively) a
programmable entrance code to the sensor 510 preferably
located within the external handle 30. Those skilled in
the art will recognize that the circuit may be a
proprietary integrated circuit (IC) or may be implemented
WO 96141486 219 6 7 5 0 PCT~S96/07722
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using discrete components as will be described herein. As
noted above, the standard key cylinder of a current typical
door lock is replaced in the EDL by the sensor 510 and an
electromechanical device 21 which reside within the
exterior handle 30. An electronic package 500 resides
within the interior handle 25.
The microprocessor 505 of the EDL 500 (shown in Fig.
7) communicates with the HHC 400 via sensor 510. The
entrance code is verified and if it matches a pre-
programmed code which resides in a local nonvolatile
memory, then electromechanical device 21 is actuated to
switch the EDL to an unlocked (or locked) state. In the
preferred embodiment the electromechanical device 21 is a
miniature DC motor with a 256:1 gear reducer 22. The
electromechanical device rotates the locking rod 23
approximately 1/4 turn either clockwise or counterclockwise
to switch the lock to a locked or an unlocked state,
respectively. In the preferred embodiment, the switching
operation is accomplished within less than one second,
although those skilled in the art will immediately
appreciate that the gearing, motor shaft speed, voltage
applied to the motor, and lock type will all affect the
time in which the locking operation occurs. The gear
reducer 22 is cooperatively connected to a non conductive
disk 57 with a single pole switch having two end contacts
57' thereon (best seen in Figs. 1, 3 and 3A). Disk 57
interacts with leaf spring contact 58 to stop the motor 21
when the EDL is switched to either a locked or an unlocked
state. When either one of the limit switches is engaged a
signal is transmitted back to the HHC to verify that'the
EDL is either locked or unlocked. The HHC contains a bi-
-color LED (412) which is lit briefly upon receipt of the ,
confirmation signal from the EDL (e. g., green when
unlocked, and red when locked) to provide sensory feedback
to the user. Those skilled in the art will immediately
.a- WO 96141486 219 6 7 5 0 PC.l.~s96/07722
- 23 -
recognize that other sensory signals might also be
incorporated, such as an audible confirmation signal.
The mechanical actuation of the door lock (i.e.,
opening of the door from the outside using handle 30 or
from the inside using handle 25).is provided by the user
after the EDL is internally switched to the unlocked (or
locked) state. Thus, the user provides the torque to bias
the spring loaded rotating shaft 30f to retract the
doorlatch 31. Thus, since the DC motor 21 only needs to
rotate the locking rod 23 and cam 223, a very small low
torque motor may be utilized which need not rotate about a
long arc. In the preferred embodiment, the shaft of the
gear reducer 22 can be rotated about an arc of only 10' in
order to successfully switch the EDL from the locked to the
unlocked position (and vice-versa). However, the amount of
rotation is a matter of design choice and type of locking
mechanism with which the EDL is utilized, as will be
appreciated by those skilled in the art. The limit switch
57 located on the gear reducer 22 while being used to cut
the power to the motor 21, is also used, after a brief
delay, to turn off the power to the rest of the electronic
package 500 of the EDL in order to conserve power. Those
of skill in the art will also recognize that since a
processor is utilized, it might be advantageous in certain
instances to monitor the current drawn by DC motor 21 to
determine when the rotation required to lock or unlock the
locking mechanism has been completed (i.e., assuming that
the shaft rotation will be stopped by the locking mechanism
itself after a rotation through a certain arc, as in the
preferred embodiment and other typical locks, thereby
stalling the motor after which a larger current is drawn
through the motor), rather than by utilizing the preferred
mechanical limit switch discussed herein.
As noted above, the interior handle 25 of the EDL is
equipped with a central button 29a for manual switching of
WO 96/41486 219 6 7 5 0 PCT/US96/07722 --
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the EDL from the locked to the unlocked state and vice-
versa. The button 29a replaces the mechanical door switch
on existing door hardware. Built-in LEDs or liquid crystal
display means 29b are used to provide a visual indication
of whether the door 19 is locked. or unlocked. The display
means 29b also can be used to provide a visual indication
to the user that the door electronics "program mode" (as
hereinafter described in more detail) has been activated
(as for example by flashing LED signals), and successful
completion of the activity (e.g., flashing stops). In the
embodiment illustrated, the electronic package S00 and the
battery 28 are inserted in the interior handle 25 of the
EDL. Although not tested, preliminary calculations
indicate that the battery 28, preferably lithium, of the
EDL should provide enough energy to power the EDL for at
least ten years. Preferably the battery 28 can be replaced
only from the inside of the door 19 through the battery
compartment plate 54 of inside handle 25. When the battery
28 loses approximately 90 percent of its capacity, a
warning signal is preferably transmitted from the EDL to
the HHC every time the EDL is activated, and preferably a
buzzer is enabled inside the EDL. Therefore, every time
the EDL is activated, the HHC produces a brief audible
warning signal to the user when the EDL battery 28 is low.
A different audible signal is generated when the battery
(not shown) of the HHC itself is low. In case the EDL
battery 28 is not replaced in time, optionally the exterior
section of the EDL may be equipped with a proprietary
miniature port (not shown) which may be used to power the
EDL electronics. This port may be accessed by an
authorized service personnel, and is preferably
electronically protected from overvoltage or shorts (e. g.,
with a diode). Alternatively, a photovoltaic cell (not
shown) may be installed in the EDL which can charge the
,~ WO 96/41486 219 6 7 5 0 pCT~S96/07722
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EDL's battery 28 when the cell is illuminated with direct
light.
The EDL microprocessor 505 is programmed to accept an
emergency code in the event that the HHC is lost (the EDL
preferably cannot be locked from.the outside without the
HHC). This code is preferably comprised of two segments.
The first segment of the emergency code is a standard
factory code which may also be programmed into emergency
HHCs carried by authorized service personnel. The second
segment is a personal emergency code which is either
programmed into the EDL at the factory or optionally after
installation by the owner. The emergency HHC is equipped
with an alphanumeric keypad (or the optional keypad unit
could be used) which can accept the personal segment of the
emergency code from the owner. To add additional security,
the personal segment of the emergency code can be arranged
and configured to be changed after the door is unlocked by
the authorized service personnel. If RF communication is
utilized, the emergency code can be remotely transmitted
from an authorized service center and/or a security
service.
Entrance Coding Scheme
Next, referring to Fig. 9, a discussion of the
preferred coding scheme of the EDL will be presented. The
EDL preferably can store 64 entrance codes. Each entrance
code is comprised of 64 bits. Therefore, there is a
possible 264 potential combinations (for reference, 232 is
approximately 4.3 billion). The first code of the 64
entrance codes is the specific lock code ("SLC"). The
remaining 63 entrance codes may be preferably used for
"master" and "submaster" HHCs (i.e., allowing a single HHC
to access to any number of assigned EDLs). An individual
HHC only transmits one entrance code. However, any number
of EDLs can have that code entered as one of its 64
entrance codes.
WO 96/41486 219 6 7 5 0 pCT~S96/07722 w
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When the entrance code of an HHC is programmed to
match the SLC, the HHC can only lock or unlock a specific
EDL (assuming that SLC codes are not duplicated in other
locks). The HHC can operate in a "master" or "submaster"
mode if it is programmed to transmit one of the other 63
codes (i.e., one of the codes programmed into an EDL as an
entrance code). The codes may be assigned a "priority
level" such that a "priority 1" code can lock and unlock
any EDL in a given area, while codes with priorities 2, 3,
4, etc. can lock or unlock a smaller number of EDLs.
Figure 9 illustrates an example of this entrance code
priority level scheme.
Thus, the present preferred system allows for 62
levels of "submasters" in addition to the main "master"
code. Those skilled in the art will appreciate that
different priority levels cannot have the same code to
prevent HHCs with lower priority from locking or unlocking
EDLs which are limited to higher priority HHCs. This
priority method allows for a very effective enforcement of
limited access to sensitive areas. Those skilled in the
art will also appreciate that a given EDL and a number of
matching HHCs can be programmed to have the same SLC by the
manufacturer or by the owner with the use of an EDLP 600
(described below).
Communication Scheme
The communication between the HHC and the EDL is based
on spread spectrum communication (SSC). This technique
allows for a frequency of a given carrier signal to change
continuously with time according to a preset time-varying
frequency program. Unlike standard frequency modulation
(FM) in which the carrier frequency varies by a small
percentage, the frequency variation of the carrier signal
in SSC is virtually unlimited. Therefore the bandwidth of
the SSC carrier can become extremely broad and allows for
the transmission of vast amounts of lower frequency digital
..._, WO 96/41486 219 6 7 5 0 PCT/US96/07722
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information such as the various entrance codes of the
present electronic lock system.
Referring next to Fig. 10, the amplitude of the
transmitted carrier is illustrated as being keyed (i.e.,
switched on and off) by the digital information of the
entrance codes. In order to receive the transmitted
signal, however, the receiver must be able to tune to a
synchronized duplicate of the transmitter's frequency
program. The digital information is then obtained by
standard demodulation techniques. The mini~tum bandwidth
necessary to transmit the desired information is called the
information bandwidth.
The advantage of using SSC versus other common methods
of information transmission (e.g., AM or FM) can be
quantified by the process gain (Gp) which is the ratio
between the overall carrier bandwidth and the information
bandwidth. As those skilled in the art will recognize, a
major advantage of the SSC technique is that the signal-to-
noise ratio of the communication system is improved by a
factor which is equal to Gp. Because GP for SSC is
normally larger than GP for other communication techniques,
the signal to noise ratio of an SSC system is far superior
to those systems. Additionally, SSC has better radio
interference immunity compared to other transmission
systems.
The time-varying programmed changes in the frequency
of the carrier is commonly called frequency hopping, and is
normally accomplished in an electronic circuit called a
frequency synthesizer (discussed below). For successful
decoding of a set of given information, the transmitter and
receiver must use the same time-synchronized frequency
program. The protocol for such synchronization is quite
complicated. However, the present invention utilizes a
communication method which eliminates the need for a
synchronization protocol. In the present system the
WO 96/41486 219 6 7 5 0 PCT/US96/07722
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frequency program is transmitted to the receiver as part of
the transmitted information. Thus, the receiver must be
tuned to an initial default frequency of the SSC signal in
order for the communication procedure to begin.
The procedure for communication between the HHC and
EDL can therefore be summarized as follows. Still
referring to Fig. 10, first, when the HHC is activated, an
initializing pulse is transmitted to the EDL which turns on
its electronic package 500 (the EDL is normally "dormant"
to conserve battery 28 power). Then a second pulse (a
control bit) is transmitted to the EDL to indicate whether
the user wishes to lock or unlock the EDL. If the EDL is
already at the desired state a confirmation signal may be
transmitted by the EDL to the HHC, and an appropriate
"locked" or "unlocked" LED 412 built into the HHC may flash
or otherwise provide a sensory signal to the user.
The entrance code is preferably transmitted in
segments of eight bits interrupted by eight bits for the
next carrier frequency code, however, other numbers of bits
might be used. For an eight bit segment, 256 discrete
carrier frequencies (as for example between 15 kHz and 1
MHz for IR communication, or 902-928 MHz, 415 MHz or 1.2
GHz for RF communication) are used. Those skilled in the
art will recognize that with a larger number of
frequencies, the transmission looks more like noise and is
more difficult to successfully decipher the code. Each of
these carrier frequencies is identified by an eight bit
code. During the interval in which the HHC communicates
with the EDL, a new frequency code is selected by the HHC
at random after the transmission of each eight bit segment
of the entrance code. (Only the initial carrier frequency
is fixed so that communication between the HHC and the EDL
can be established). The random code is selected by
choosing an eight bit code and going to a look-up table
stored in EPROM which correlates the eight bit code to a
2196750
-- WO 96/41486 PCT/US96/07722
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frequency. This new frequency is then delivered to the
frequency synthesizer 408 of the HHC. The HHC then
transmits the eight bits of the entrance code and then
eight bits which identify the next carrier frequency to the
EDL. The carrier frequency of the HHC changes before the
next eight bits of the entrance code and the next carrier
frequency code are transmitted. The transmission is
concluded when eight groups, each group being comprised of
eight bits of the entrance code and eight bits of the next
carrier frequency, are transmitted.
The EDL decodes the transmitted information using the
coded carrier frequencies and converts it into a digital
code. The EDL must have an identical look-up table
correlating carrier frequencies with eight bit codes to
that look-up table found in the HHC, or the information
will not be properly decoded by the EDL. Thus, not only is
the EDL protected by the 64 bit entrance code, but it~is
also protected by the random combination of carrier
frequencies over which the entrance code may be
transmitted.
Assuming complete reception of the codes, the code is
then compared with the codes stored in the EDL's
nonvolatile memory, and if there is a match, the DC motor
21 is activated to switch the EDL to a locked (or unlocked)
state. When the DC motor 21 stops and the limit switch 57
is engaged, a confirmation code may then be transmitted to
the HHC if desired.
It will be appreciated by those skilled in the art
that since any of the 256 carrier frequencies might be
utilized at random, for successful communication between a
given HHC and an EDL, it is necessary that all 256 carrier
-frequencies which might be utilized by the HHC must also be
utilizable by the EDL, even though only a maximum of eight
carrier frecruencies are used each time the HHC is
activated. Hence, the SSC transmission scheme can
WO 96/41486 219 6 l 5 0 PCT/US96/07722 --
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drastically reduce the number of HHC's which can
communicate with a given EDL because it is possible to
produce groups of HHC's and EDLs that have different
matching sets of carrier frequencies which are preset at
the factory. Obviously, HHCs and EDLs from different
groups cannot communicate because their programmed carrier
frequencies do not match (except due to an extremely remote
fortuitous occurrence). Thus, in addition to the security
provided by the entrance code itself, the number of HHCs
which can actually establish communication with the EDL may
be restricted by the manufacturer. Additional HHCs can be
matched to a given EDL by specifying the EDL "type" (e. g.,
a serial number). Users of large numbers of EDLs can
arrange with the factory to have a specific group of 256
carrier frequencies assigned especially to them. Those
skilled in the art will also appreciate that any number of
frequencies might be utilized, and that the number of
frequencies (as well as the eight bits used to correlate
the frequencies) are a matter of design choice, with the
cost and method of transmission being factors, among
others.
An important advantage of SSC is that it virtually
eliminates duplication or decoding of an HHC. In the event
that an HHC does not match a given EDL, and additional
codes are received by the EDL the electronic circuit is
preferably disabled for three minutes after a predetermined
number of unsuccessful attempts. The purpose of this
procedure is to prevent unauthorized users from
methodically scanning through all possible codes.
When the microprocessor senses a malfunction in the
hardware it may switch to an optional secondary electronic
system (not shown). The secondary system is preferably
identical to the primary system. While this secondary
system provides redundancy for important locking
applications, its additional cost and size may not make it
2196750
WO 96/41486 PCT/US96/07722
- 31 -
practical for all embodiments of the present invention.
The EDL may also transmit a warning to the HHC when a
secondary system is in operation, resulting in an
audiovisual warning for the user in the HHC.
HHC 400 (and Keypad 1000) Electronics
Next presented will be a description of the HHC
electronics module 400. Fig. 1 illustrates a device 900,
which may be either an HHC device 400 or an EDLP 600. Fig.
1 also illustrates an optional keypad device 1000, which
may be used in combination with the HHC. Keypad units and
their general construction and functional capabilities are
well-known in the art and will not be detailed herein. For
the purposes of this description, the keypad device 1000 is
generally a remotely located stationary device that
communicates with the EDL 500 to lock and unlock~the door
lock hardware in the same manner as the HHC device 400, but
which has the additional capability of selectively
accepting a number of personal identification numbers
"PINS." The keypad is generally configured for mounting
outside near the door and has a plurality of numeric keys,
generally indicated at 1001 (preferably 10), plus lock and
unlock buttons 1002 and 1003. The keypad also includes a
plurality of LED visual indicators 1012 and an audible
sensory communication device such as a horn (not
illustrated). A user will enter a PIN. If the keypad
electronics finds the PIN acceptable, the unlock button of
the pad will be enabled. The lock button will always be
enabled. The electronics for processing PIN identifiers
and for enabling a system in response thereto is well-known
in the industry and will not be belabored herein. Each
keypad, like the HHC devices, also has a unique serial
number, and has the same general electronic circuitry as
the HHC device (to be hereinafter described) for
communicating with the EDL 500.
WO 96/41486 219 6 7 5 0 pCT~S96/07722
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In the preferred embodiment, the HHC electronics
module 400 and the EDL electronics module 500 are comprised
of similar functional blocks/components. Accordingly, the
description of similar components (i.e., MPU 405 and 505)
will not be gone into at length below in connection with
EDL electronics module 500.
Referring to Fig. 6, under normal conditions the HHC
is dormant. This is accomplished by means of a Watchdog
Timer 401. The HHC has two switches 402 and 403 which
provide the "unlocked" and "locked" functions,
respectively. When either of the two switches 402, 403 is
pressed, the PIO (Parallel Input/output) 404 will generate
an interrupt request for the MPU (Micro Processor Unit) 405
which effectively turns the HHC hardware on. The HHC is
turned off by the confirmation signal from the EDL when it
is switched into a locked or an unlocked state. If no
confirmation signal is received, then the Watchdog Timer
401 turns the electronics module 400 off. The carrier
frequency program, and the EDLP access code reside in
nonvolatile RAM (Random Access Memory) 406. The
initializing pulse is transmitted by synthesizer 408 at a
given default frequency (e.g., either 40 Khz for IR or 4
Mhz for RF) .
The MPU 405 is preferably a controller manufactured by
Motorola having a designation of MC6805. However, any
processor/controller which provides for input/output, can
decode input signals, and fetch and store information from
memory and is preferably capable of half-duplex
communication might be utilized, as those skilled in the
art will recognize.
The foregoing programming of the carrier is
accomplished via the frequency synthesizer 408 which is
controlled by MPU 405. The program which executes this
control resides in ROM 407. This program produces the
sequence of eight 16 bits words each consisting of 8 bits
_. WO 96/41486 219 6 7 5 0 PCT~s96/07722
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of SLC and 8 bits of carrier frequency code (The carrier
frequency changes before the next 8-bits of SLC is
transmitted). The output of the synthesizer 408 is then
switched on and off sequentially according to the digital
content of each 16 bit word. In. the preferred embodiment,
the synthesizer 508 is actually the transmitter. The IR or
RF sensor 410 (this device is either an IR source combined
with an IR detector, or a wideband antenna) is normally in
the receive mode but is switched by the receiver 409 to the
transmit mode if the output of the frequency synthesizer
408 is nonzero. The transmission of this information is
preceded by an initializing bit followed by a control bit
which informs the EDL whether it is to be switched to a
locked or an unlocked state. Communication between the HHC
(keypad) and the EDL electronics can occur at any desired
frequency range, but most often is limited by governmental
agencies such as the FCC to limited band ranges. In the
preferred embodiment, the nominal communication frequencies
used are 1.2 GHz, 900 MHz and 415 MHz, depending upon the
use application for the door locking hardware.
In the preferred embodiment, the sensor 410 is
comprised of an IR detector (manufactured by General
Electric having the designation L14F2) and an IR emitter
(manufactured by General Electric having a designation
LED56). The frequency synthesizer 408 generates a
frequency carrier that is proportional to a binary "word"
that is provided to its input by MPU 405. In addition
there is another input which can be used by MPU 405 to
disable frequency synthesizer 408 output. In the preferred
embodiment, the frequency synthesizer used is manufactured
by Motorola having the model designation MC4046.
Receiver 409 (best seen in Fig. 11), used to receive
signals from the EDL 500, is connected to the sensor 410
and frequency synthesizer 408, and mixes the signals at
mixer block 409a. The output of the mixer 409a is the
WO 96/41486 219 6 7 5 0 PCT/US96/07722 w
- 34 -
input frequency from the sensor 410 minus the frequency
synthesizer 408 frequency. This output is provided to IF
amplifier block 409b, which amplifies the signal for
detector block 409c. Detector block 409c removes the high
frequency (carrier) components. Those skilled in the art
will recognize that by changing the frequency of
synthesizer 408, the receiver can be tuned at different
frequencies. The decoded signal is then provided to MPU
405. In the preferred embodiment, receiver 409 is
manufactured by National Semiconductor having the model
designation LM1872N.
The confirmation signal from the EDL is received by
receiver 409. The MPU 405 recognizes whether the EDL is
locked or unlocked and one of the LEDs 412 is turned on for
3 seconds. If an attempt is made to switch the EDL to a
state to which it is already switched, the appropriate LED
flashes for 3 seconds.
In the event that the EDL's MPU 505 senses a
malfunction which prevents the EDL from completing a giver
function, a warning signal is transmitted to the HHC. This
signal is recognized by the HHC's MPU 405 which toggles the
LEDs 412 and enables an audible warning using buzzer 420.
Failures of the HHC itself are signaled with a different
(audible) signal using buzzer 420. For example, the HHC
can be equipped with a second optional backup circuit and
such a signal may be issued when the monitor 411 switches
to the backup circuit when it senses a failure in the
primary hardware of the HHC. Also, the HHC battery may be
monitored by MPU 405, and when the battery voltage drops
below 900 of its nominal value, buzzer 420 sounds when the
HHC is activated.
In the preferred embodiment the electronic package of
the HCC measures l2mm x 8mm. This package is preferably
built around a proprietary integrated circuit and hence the
power dissipation is kept to a minimum. The HHC is
~... WO 96/41486 219 6 7 5 0 PCT~S96107722
- 35 -
preferably built in a small package which might typically
measure 2.5 cm x 1.5 cm x 0.5 cm.
The HHC and the keypad can be programmed with the EDLP
600. The communication between the HHC (keypad) and EDLP
is established via IR or RF transmission using SSC. An
initializing code advises MPU 405 that the entrance code is
to be reprogrammed. The EDLP then sends an access code to
the HHC which MPU 405 compares with the access code
residing in RAM 406. If the code matches, the SLC and the
access codes of the HHC can be programmed. Note that the
programmer must have the same frequency program as the HHC
for successful communication.
EDL Electronics 500
Next is a description of the EDL electronics module
500. As previously noted, the functional components are
similar to those previously described with regard to the
HHC and keypad, and will therefore be discussed only
generally in terms of function in the EDL. Referring to
Fig. 7, under normal conditions the EDL is dormant. When
the initializing pulse transmitted by the HHC is sensed,
the EDL is switched on and the receiver 509 is tuned to a
default frequency of either 40Khz (IR) or 4 Mhz (RF). The
sensor 510 is either a combination of IR detector/source or
a wide-band antenna. The signal received by the sensor is
then fed to the receiver 509. This signal (best seen in
Fig. 10) is comprised of 1 bit (control bit) of information
indicating whether the EDL is to switch to the locked or
unlocked state, followed by eight 16 bit words each
containing 8 bits of entrance code and 8 bits of carrier
frequency code. The MPU 505 recognizes the control bit and
determines the direction of rotation of the DC motor. The
first 8 bits of each 16 bit word are used to construct the
entrance code while the last 8 bits are the code which
identifies the next frequency so the receiver can be tuned
to the carrier frequency of the next transmission (which
WO 96/41486 2 19 6 7 5 0 PCT~S96/07722
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contains another 16 bit word). At the end of the
transmission MPU 505 tunes the receiver 509 to the default
frequency.
Once the 64 bit SLC code is received by the MPU 505,
the received entrance code is compared with the codes
stored in RAM 506 which can contain up to 64 codes (best
seen in Fig. 11). If a match is found, the MPU 505 sends a
signal to PIO 504 which enables the DC motor 21. The motor
21 turns either clockwise or counterclockwise depending on
the status of the control bit. The motor continues to turn
until one of the two end contacts of the limit switch (Fig.
3A) is engaged and a confirmation signal is sent by PIO 504
to MPU 505. The sensor 510 is optionally switched to a
transmit mode and frequency synthesizer 508 transmits the
confirmation to the HHC. A different confirmation signal
is transmitted to the HHC if the DC motor 21 does not move
because of an attempt to switch the EDL to an existing
state.
If the code transmitted to the MPU 505 does not match
any of the codes stored in RAM 506, MPU 505 increments by 1
an internal counter which is reset to 0 every time the EDL
is dormant. When the output of this counter is 3, MPU 505
switches the EDL to a dormant mode which cannot be
interrupted for three minutes. At the end of the three
minutes the EDL remains in the dormant mode until it is
awakened again.
Fig. 12 illustrates a logic flow diagram of an
embodiment of the program logic which might be resident in
MPU 505, RAM 506 or ROM 507. In Fig. 12, the logic diagram
is shown generally as 700. The logic flow diagram 700
illustrates the steps taken to analyze the logical status
of the received entrance code from the HHC.
Although the MPU 505 will be characterized as
"preceding" from logical block to logical block, while
describing the operation of the program logic, those
WO 96/41486 219 6 7 5 0 PCT/US96/07722
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skilled in the art will appreciate that programming steps
are being acted on by MPU 505.
In operation, MPU 505 starts at block 701. MPU 505
then proceeds to block 702 to initialize two variables to
zero which will be used in control loops in the logic flow
700. At block 703, the first 8 bits of entrance code are
received from receiver 509 and the 8 bits are stored in RAM
506. As discussed above, the last 8 bits of the first
received word are utilized to change the carrier
frequency). MPU 505 must determine if the received carrier
code is a valid code. Therefore, MPU 505 proceeds to block
705 and compares the received carrier code to a look-up
table in nonvolatile RAM 506 in order to find the correct
word to deliver to frequency synthesizer 508 to tune
receiver 509 for the next transmitted word from the HHC.
Additionally, at block 705, MPU 505 determines whether a
proper carrier frequency was found. If the carrier
frequency is found in the look-up table, the MPU 505
proceeds to block 706 where the first control loop variable
is incremented. MPU 505 then proceeds to block 707 where
it is determined whether the entire 8 groups of entrance
codes and carrier frequency codes have been received. If
more codes are to be received, MPU 505 returns to bloc; 703
to receive the next group.
In the event that the carrier frequency is not found
in the look-up table at block 705, MPU 505 proceeds to
block 709 where it is determined whether a valid code is
being generated. If a valid code is not being generated, a
second control loop is incremented at block 710 and at
block 711 it is determined whether the improper code
control loop has been incremented three times. If three
invalid codes have been reached, then the EDL is disabled
at block 712. If the second control loop has not reached
three, then at block 713 the first control loop variable is
WO 96/41486 219 6 7 5 0 PCT/CTS96/07722
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initialized to zero and MPU 505 proceeds to block 703 to
begin receiving a new transmission from the HHC.
Once the entire entrance code is received at block
707, MPU 505 proceeds to block 708 where MPU 505 retrieves
the entire 64 bit entrance code from RAM 506. MPU 505 then
proceeds to block 709 to compare the 64 bit code against
the 64 codes stored in the nonvolatile RAM 506. If the
code matches, MPU 505 proceeds to block 710 to send
confirmation to the HHC. If the code is not valid, then
MPU 505 proceeds to block 710 through the second control
loop. Once the confirmation is sent to the HHC, MPU 505
Watchdog Timer (not shown) times the system out and the EDL
electronics module 500 goes dormant. The logic flow 700
ends at block 715.
An important optional function of MPU 505 is the
programming of the voltage to the DC motor 21.
Considerable battery power may be conserved by rapid
switching of the voltage to the motor 21 during its
operation. This scheme exploits the inertia of the
permanent magnet of the motor 21 (i.e., the rotor) when the
power to the motor 21 is turned off. MPU 505 may also
monitor the electric current through the motor. When the
motor current is 27o higher than the nominal operating
current, MPU 505 disconnects the power from the motor 21 to
prevent permanent damage, transmits a warning signal to the
HHC 400 and enables buzzer 520. When the voltage of the
EDL's battery drops below 90a of its nominal value, a
warning is transmitted to the HHC and buzzer 520 is enabled
every time the EDL is activated. The program code executed
by the MPU 505 resides in ROM 507. Monitor 511
periodically checks the hardware of the EDL. When a
malfunction is sensed, monitor 511 switches to the
emergency secondary system, a warning signal is transmitted
to the HHC, and the buzzer 520 is enabled. In order to
conserve power, the EDL hardware is checked only when the
WO 96/41486 219 6 7 5 0 pCT~S96/07722
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EDL is activated. The EDL is switched to the dormant state
by a Watchdog Timer (not shown) after the confirmation
signal is transmitted to the HCC.
The electronic package 500 of the EDL is preferably
based on a proprietary integrated circuit and hence has the
same approximate physical dimensions as the HHC electronic
package 400. When the EDL is in the dormant mode, the
current drain from its battery is extremely small.
The EDL can be programmed with the EDLP 600. The
communication is established via IR or RF transmission
using SSC. An initializing code advises MPU 505 that the
entrance code is to be reprogrammed. The EDLP then sends
an access code to the HHC which MPU 505 compares with the
access code residing in RAM 506. If the code matches, any
number of the 64 entrance codes can be changed, as well as
the emergency code and the EDLP access codes of the EDL.
Note, however, that in the preferred embodiment the EDLP
must have the same frequency program as the EDL for
successful communication.
EDL Programmer (EDLP) 600
Another part of the present system is the
EDL/HHC/keypad Programmer (EDLP) 600 which is a handheld
microcomputer, a functional block diagram of which is
illustrated in Fig. 8 generally at 600. The EDLP is
configured and packaged as a handheld calculator and has an
LCD display which is used to instruct the user how to
proceed with the programming of the EDL, the keypad or the
HHC (using menu-driven software).
The EDLP can be used to program any 64 bit
alphanumeric code into the HHC or keypad, and a sequence of
64 alphanumeric entrance codes (each 64 bits) into the EDL.
The EDLP consists of MPU 604 which executes a program
stored in ROM/RAM 605. This is a user-friendly menu-driven
program that guides the user through its various stages and
has an ON-LINE HELP facility. Interactive input and output
WO 96/41486 219 6 7 5 0 PCT/US96/07722
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are provided through display 608 and keypad 607. The
general purpose I/O PIO 606 formats the input from keypad
607 to digital information, and converts the output of MPU
604 to alphanumeric characters which appear on display 608.
The operation of sensor 601, receiver 602, and frequency
synthesizer 603 is similar to the operation of the
corresponding components in the HHC, keypad and EDL.
The programming of an HHC, keypad or an EDL can only
be accomplished if it is initialized with a personal access
code which matches an access code in the EDL, keypad or
HHC. The access code is programmed into the HHC, keypad or
EDL at the factory, and can be changed by the owner after
installation. The programming of the EDL, keypad or HHC is
carried out via IR or RF transmission using SSC. The EDLP
sends an initializing code which advises the local MPU of
the device being programmed that the entrance code is to be
reprogrammed. The EDLP then sends an access code to the
HHC, keypad or EDL which is compared with the access code
residing in the local RAM of the HHC, keypad or EDL. If
the code matches, the HHC, keypad or EDL can be programmed.
Note that the EDLP must have the same frequency program and
initial default frequency as the HHC, keypad or EDL for
successful communication. When the programming is
completed the programmed code is transmitted back to the
EDLP for verification. Figure 13 illustrates a logic flow
diagram at 800, of a program which may be utilized by EDLP
600.
Initialization and Adding HHC's or Keyr~ads
An initialization sequence is contemplated for
initiating first time operation of a system after
installation. This will generally occur whenever the
battery for the EDL electronics is inserted into the
system, or replaced. To initialize the system, the user
will place the EDL electronics into its "program mode."
Next, either the lock or unlock button of the HHC or keypad
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which the user wishes to install is depressed. The HHC or
keypad then transmits its coded signal (as previously
described) to the EDL. The EDL will process the
transmission as previously described to check that the
received serial number is for an.approved device. The
process can be repeated for initializing any desired number
of HHC's or keypads before leaving the program mode.
When a user wants to add an additional HHC or keypad
to the EDL's approved list, the user will first place the
EDL into its program mode. He will then depress either the
lock or unlock button of an HHC or keypad that has already
been approved (installed), and will then depress the lock
or unlock button of the HHC or keypad that is to be added
to the approved list. The user then again depresses the
lock or unlock button of the previously approved HHC or
keypad so as to "sandwich" the new entry between signals
from a previously approved device. This technique will
preclude a casual visitor from installing or authorizing a
new HHC or keypad for use without the knowledge or approval
of a prior user.
Alternative HHC Embodiment
The HHC can alternatively be replaced with a
relatively inexpensive device which comprises a coded two-
dimensional backlit graphic pattern measuring approximately
1 cm x 1 cm, although other sizes might be used. The EDL
is equipped with an optical window which is used to image
the pattern of the HHC onto a square two-dimensional
photodiode array comprised of 256 elements (arrays having
more or less elements might also be utilized). The array
is electronically scanned inside the EDL by scanner 512
(best seen in Fig. 7), and the pattern is decoded and
compared with other codes residing in memory. The cost-
effective HHC of this embodiment does not utilize two-way
communication and may include no battery since the back
lighting of the pattern can be accomplished using
WO 96/41486 219 6 7 5 0 PCT/US96/07722
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phosphorescent materials. Additionally, this method could
be expanded to include complex optical pattern recognition
in the EDL and the replacement of the HHC by positive
identification of fingerprints.
Alternate Door Locking Mechanism
An alternate embodiment of a door hardware locking
mechanism that practices the principles of this invention
and which uses longitudinal motion along the latch axis to
achieve the locking function is illustrated in Figs. 14-18.
Referring thereto, components of similar functions to those
previously described with respect to the first embodiment
of Figs. 1-5 are characterized by the same reference
characters as used in the first embodiment, followed by a
prime (') designation. Unlike the locking structure of the
first embodiment, that of the second embodiment places all
of the electronics of the system, except for the antenna,
on one side of the door, preferably within the door handle
and associated parts thereof located on the "inside"
portion of the door hardware assembly, and/or within the
space available between the rose or escutcheon plate and
the door surface. The second embodiment also uses a simple
linear or longitudinal motion along the lock axis to
perform the locking/unlocking functions, thereby
eliminating the gear reduction assembly of the first
embodiment, and thereby physically compacting the
electronic assembly. The second embodiment configuration
also reduces the number of moving parts of the mechanical
locking structure of the door hardware, thereby
theoretically improving the long term reliability and ease
of maintenance of the door hardware assembly.
Referring to Figs. 14-16, an example of the linkage
mechanism of a second embodiment of a conventional door
hardware locking apparatus which has been modified to
incorporate the principles of this invention is
illustrated. Figs. 14-16 illustrate the "inside" handle
WO 96/41486 219 6 7 5 0 pCT~S96/07722
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assembly portion of a door hardware locking apparatus 20'.
The electronics module 500' is virtually identical to that
previously described with respect to the first embodiment
and contains the electrical components of the EDL
previously described with respect to the first embodiment.
As will become apparent upon a more detailed description of
the door hardware assembly 20', the electronics module 500'
is sized and configured to be physically mounted within the
inside hollow knob 25' or within a lever-type of inside
knob, generally indicated at 25a. Alternatively, or in
combination with the above described placement, all or
portions of the electronics module 500' may be placed
within the space available under the rose or escutcheon
plate portion 53' of the door hardware.
The interior handle portion of the door hardware 20'
includes a mounting bracket 50' that is fixedly secured
from movement relative to the door 19 through a bore in the
door, to a corresponding mounting bracket 30a' for the
external handle portion (see Fig. 14). A hollow
cylindrical shaft 26' is rotatably mounted to the bracket
50' for rotation under spring tension from spring 52' about
the axis 18'. When the door hardware 20' is mounted to the
door 19, the shaft 26' extends through the inside cover
plate 53'. The inner door handle 25' (or 25a) is
detachably secured in a manner well known in the art to the
hollow sleeve 26' such that the sleeve can be rotated
against the bias of the spring 52' by turning movement of
the handle 25' about the axis 18'.
Unlike the first embodiment door hardware 20
configuration, in the second embodiment door hardware 20'
configuration, all of the electronic circuitry 500', the
-high efficiency cylindrical battery pack 28' and the DC
motor assembly 21' are physically located on the same side
of the door hardware assembly 20', namely on the "inside"
door handle portion of the assembly or under the rose or
WO 96/41486 219 6 7 5 0 PCT~S96/07722
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escutcheon plate 53'. In the preferred configuration of
the second embodiment illustrated in the figures, the
electronics module 500', the battery 28' and the DC motor
21' are coaxially mounted along the axis 18'. The sensor
510 or antenna may be located either in the outside handle
portion of the door hardware 20' or adjacent the
electronics module 500' in the inner handle. The battery
28' and the DC motor 21' are retainably held in position by
means of a two-part plastic sleeve retainer assembly 21a'.
The electronics module 500' is secured to the outer end of
the retainer sleeve 21a' and is accessible through the end
of the inner doorknob 25', as indicated in Fig. 14.
Appropriate electrical connections (not illustrated) are
made between the electronic circuits of the electronics
module 500', the DC motor 21' and the battery pack 28', as
will be appreciated by those skilled in the art. A drive
screw 40 is secured for rotation with the drive shaft 59'
of the motor 21' about the axis 18'. As will be
appreciated upon a more detailed description of the door
hardware assembly 20', the drive screw 40 directly provides
the axial drive force for the doorlatch assembly, and does
not require a gear box assembly as was the case with the
doorlatch assembly 20 of the first embodiment.
The forward end of the cylindrical sleeve 26' passes
through the central bore of the mounting bracket 50' for
rotatable movement with respect thereto, in a manner well-
known in the art. The sleeve 26' is keyed along its length
to slidably receive inwardly projecting tabs of a spring
driver 41 such that the spring driver 41 rotatably moves
with the sleeve 26' about the axis 18'. The spring driver
41 operatively engages the lever torsion spring 52' such
that when rotational pressure from the sleeve 26' is
released, the spring 52' will exert rotational forces to
the spring driver 41' sufficient to return the sleeve 26'
to its "neutral" position. The forward ends of the
___ _ __._ _._.._ n _ .__._.__. _
..r WO 96/41486 219 6 7 5 0 PCT~S96/07722
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cylindrical sleeve 26' are secured by means of an inside
spindle assembly, generally indicated at 42. The spindle
assembly 42 terminates at a retaining disk 42a which
secures the forward ends of the sleeve 26'. The retainer
disk 42a engages and seats upon the inner surface of the
mounting bracket 50' for preventing longitudinal axial
movement of the sleeve 26' in the direction toward the
inside handle. The inside spindle 42 also includes a
hollow extension 42b extending from the retainer disk 42a
toward a distal end, and having an internal axial bore
sized to cooperatively receive the forward portion of the
outside spindle 30f'. The retainer disk 42a includes a
central aperture (not illustrated) sized to enable the
shaft of the outside spindle 30f' to slide therethrough.
When operatively engaged, the outside spindle 30f', the
inside spindle 42 and the sleeve member 26' are all
connected for common rotational movement about the axis
18'.
The plastic mounting sleeve 21a' as operatively
secured about the battery 28' and motor 21' enables the
composite assembly formed thereby to be longitudinally
positioned within the hollow interior of the cylindrical
sleeve 26' as indicated in Fig. 14, such that the forward
end of the drive screw 40 lies within the bore of the
mounting bracket 50' and just out of engagement with the
forward end of the outside spindle 30f' (as indicated in
Fig. 14). The outside spindle 30f' is secured for rotation
within an external mounting bracket 30a' by means of a
retainer housing member 30d' and the external cylindrical
sleeve or shaft 30b' (see Fig. 14). A second retainer and
spring driver member 30c' is also cooperatively connected
for rotation with the cylindrical sleeve 30b', and
operatively engages the outer spring 30e' of the outer
handle assembly. The forward or distal portion of the
outer spindle 30f' slidably cooperatively engages and
WO 96/41486 219 6 7 5 0 PCT~S96/07722 ---
- 46 -
passes through the sleeve portion 42b of the inside spindle
42 and axially projects beyond the retainer disk portion
42a of the inside spindle a predetermined distance, as
determined by the enlarged shoulder portion of the outside
spindle which engages the distal. end of the inside spindle
sleeve 42b.
An engagement gear member 44 having an axial bore
sized to slidably cooperatively mate with the outer
circumference of the outside spindle 30f' is secured to and
for rotation with the outside spindle 30f' by means of a
retaining snap ring 45. The engagement gear (see Fig. i6)
has a plurality of radially projecting gear teeth 44a
defining spaces therebetween for cooperatively receiving
lug members 46a of an engagement nut lug 46. The
engagement lug members 46a are configured to project
between the gear members 44a of the engagement gear 44 so
as to~prevent rotational movement of the engagement gear
44, when so engaged. The engagement lug nut 46 has a
threaded axial bore sized to cooperatively thread upon the
drive screw 40, as indicated in Fig. 14. The engagement
nut lug 46 further includes a pair of appositely disposed
cam members 46b radially projecting outwardly from the
outer surface of the engagement nut lug from opposite ends
thereof, and sized to cooperatively ride within appositely
disposed recesses 26a in the forward end of the sleeve
member 26' such that the engagement nut lug 46
longitudinally moves in the axial direction of axis 18',
but does not rotate, as the drive screw 40 rotates about
the axis 18'. The engagement nut lug 46 is illustrated in
Fig. 17 as it would operatively appear when disengaged from
the gear teeth 44a of the engagement gear, and is
illustrated in Figs. 14 and 18 as it would appear when
positioned so as to cooperatively engage the gear teeth 44a
of the engagement gear 44.
~w WO 96/41486 219 6 7 5 0 pCT~S96/07722
- 47 -
Operation of the door hardware assembly 20' of the
second embodiment will be readily understood by those
skilled in the art. The DC motor 21' is energized in a
forward or reverse mode as commanded by the electronics
module 500', to rotate the drive.screw 40 in either a
clockwise or counter-clockwise rotation about the axis 18'.
When the drive screw 40 rotates in a counter-clockwise
direction (when viewed from the left side of Fig. 14), the
engagement nut lug 46 is forced by the drive screw 40
toward the outside knob assembly and into cooperative
engagement with the outside engagement gear 44. When the
engagement not lug 46 cooperative engages the outside
engagement gear 44, the inside spindle 42 is engaged to
rotate with the outside doorknob to open the latch, thereby
placing the door hardware assembly 20' in an unlocked mode
(Fig. 18). When in an unlocked mode, the doorlatch 31 is
enabled to be withdrawn from the strike plate 33, thereby
allowing the door 19 to be opened. When the drive screw 40
is rotated in a clockwise direction (as viewed from the
left in Fig. 14), the drive screw 40 exerts forces upon the
engagement nut lug 46 tending tc longitudinally move the
engagement nut back toward the inside handle 25' (as
illustrated in Fig. 17), causing the lug members 46a to
disengage from the outside engagement gear 44 and placing
the door hardware in a "locked" mode. This enables
rotational movement of the inside spindle 42 by the inside
knob only. When the outside knob is rotated, the outside
spindle 30f' rotates but since there is no physical force
transmitting connection between the engagement nut lug 46
and the engagement gear 44, the inside spindle 42 remains
stationary. In such "locked" mode, the doorlatch 31 can
only be withdrawn from the inside. As with the first
embodiment, the length of energization of the DC motor is
controlled by a pair of limit switch contacts (not shown)
which provide control signals that indicate when the
WO 96/41486 219 6 l 5 0 PCT/US96/07722
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engagement nut is operatively engaged with or disengaged
from the engagement gear.
Other enhancements that can be implemented in the door
hardware locking system of this invention, as those skilled
in the art will appreciate, may include: (a) a local clock
in the EDLs and the HHCs to allow or prevent access at
preprogrammed times, (b) two-way communication used to
retrieve information from the EDL regarding identity of
HHCs holders and the times of access (for this purpose the
HHC may be programmed with a user ID code which is recorded
by the EDL), and (c) powering the electromechanical device
by other means, such as by electrostrictive actuators.
The circuit configuration, two-way communication, and
types of latch mechanisms described herein (among others)
are provided as examples of embodiments that incorporate
and practice the principles of this invention. Other
modifications and alterations are well within the knowledge
of those skilled in the art and are to be included within
the broad scope of the appended claims.
