U.S. patent number 3,890,608 [Application Number 05/296,561] was granted by the patent office on 1975-06-17 for door monitoring and controlling device for a security system.
This patent grant is currently assigned to C. Hager & Sons Hinge Manufacturing Company. Invention is credited to Francis C. Peterson.
United States Patent |
3,890,608 |
Peterson |
June 17, 1975 |
Door monitoring and controlling device for a security system
Abstract
A security system for monitoring and controlling the operation
of doors from a remote location includes door locks, each having a
retractable latch bolt which projects into a strike and keeps the
door from opening, auxiliary latching means which block the latch
bolt to prevent it from being retracted by a thin object passed
along the strike, operating means for manually retracting the latch
bolt, and a solenoid operated locking mechanism for locking the
operating means. The lock is further provided with a switch for
sensing the position of the auxiliary latching mechanism and
another switch for sensing the position of the locking mechanism.
The two switches are connected through a contact hinge to an alarm
at the remote location, while the solenoid is connected through the
contact hinge to an operating switch at the remote location. The
alarm is actuated not only by the sensing means but also by the
hinge as it opens. The alarm can be cancelled only by closing a
key-operated switch at the door so security personnel must
investigate the cause for an alarm.
Inventors: |
Peterson; Francis C. (Affton,
MO) |
Assignee: |
C. Hager & Sons Hinge
Manufacturing Company (St. Louis, MO)
|
Family
ID: |
23142543 |
Appl.
No.: |
05/296,561 |
Filed: |
October 11, 1972 |
Current U.S.
Class: |
340/522;
70/DIG.49; 200/61.64; 200/61.7; 292/DIG.25; 292/144; 315/84;
439/31; 340/545.7 |
Current CPC
Class: |
E05B
45/06 (20130101); Y10S 292/25 (20130101); Y10S
70/49 (20130101); Y10T 292/1021 (20150401) |
Current International
Class: |
E05B
45/00 (20060101); E05B 45/06 (20060101); G08b
013/08 () |
Field of
Search: |
;340/274,276
;200/61.62,61.64,61.67,61.68,61.7 ;315/84 ;330/4
;70/107,277,279,280,283 ;292/144,DIG.24,DIG.25 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Caldwell; John W.
Assistant Examiner: Wannisky; William M.
Attorney, Agent or Firm: Gravely, Lieder & Woodruff
Claims
What is claimed is:
1. In a security system for monitoring a door in a door frame, and
including a strike on the door frame and an alarm, an improved lock
comprising: a retractable latch bolt movable between extended and
retracted positions and normally urged to the extended position,
the latch bolt when in its extended position being projected beyond
the door for engagement with the strike to secure the door in a
closed position, the latch bolt when in its retracted position
being located beyond the strike so that the door is released from
the strike and can be opened, retracting means for moving the latch
bolt to its retracted position; a locking element movable between
blocking and release positions, the locking element when in its
blocking position preventing the latch bolt from moving to the
retracted position, the locking element when in its release
position permitting the latch bolt to move to its retracted
position, the locking element being held in its release position by
the latch bolt when the latch bolt is in its retracted position; an
auxiliary latch projecting beyond the door when the door is open
for engagement with the strike as the door is closed and being
depressed by the strike when the door is closed, the auxiliary
latch being connected with the locking element for holding the
locking element in its release position when the door is open and
the auxiliary latch is projected beyond the door, the auxiliary
latch when depressed permitting the locking element to move to its
blocking position, whereby the locking element will assume its
blocking position only when the latch bolt is in its extended
position and the auxiliary latch is depressed, and a switch
operated directly by the locking element such that the switch
condition changes with each movement of the locking element between
its release and blocking positions, the switch being electrically
connected with the alarm, whereby the switch monitors the position
of the locking element.
2. The structure according to claim 1 wherein the locking element
pivots between its release and blocking positions about an axis
fixed in position with respect to the door.
3. The structure according to claim 1 wherein the retracting means
is manually operated and includes at least one handle which is
grasped.
4. A security system according to claim 1 wherein the door is
attached to the door frame by a hinge and the alarm is connected to
the hinge and is energized when the door opens.
5. A security system according to claim 4 wherein the switch is
connected to the alarm through the hinge.
6. A security system according to claim 4 wherein the door is
attached to the door frame by a hinge having two leaves, contacts
on one leaf, and contactors on the other leaf, the hinge being
closed when the door is closed, and the contacts being engaged with
the contactors when the hinge is closed and being separated from
the contactors when the hinge is opened; and wherein the switch is
connected to the alarm through the contacts and contactors.
7. A security system according to claim 6 wherein the contacts and
contactors are in an electrical circuit with the alarm; and wherein
the alarm is energized when the circuit is interrupted at the
contacts and contactors, whereby when the door is opened the alarm
will be energized.
8. A security system for monitoring a door hinged to a door frame,
said security system comprising a strike on the door frame; a lock
on the door, the lock including a retractable latch bolt which is
capable of projecting from the door into the strike to secure the
door in a closed position, manually operable retracting means for
retracting the latch bolt, means movable to a locked condition for
dogging the retracting means so the retracting means cannot be
manually operated to open the door, and auxiliary latching means
movable between blocking and release positions for preventing
retraction of the latch bolt when in the blocking position and for
permitting retraction of the latch bolt when in the release
position, the auxiliary latching means being responsive to the
position of the door and being in the release position when the
door is open; an alarm; a first switch connected to the alarm and
monitoring the locking means such that the first switch changes
condition as the locking means moves into and out of its locked
condition and will actuate the alarm only when the locking means is
out of its locked condition; a second switch connected to the alarm
and operable by the auxiliary latching means such that the second
switch changes condition with each movement of the auxiliary
latching means between its release and blocking positions and will
actuate the alarm only when the auxiliary latching means is in its
release position; and means connected with the alarm and responsive
to the door position for operating the alarm when the door is away
from its closed position, said last named means being at the hinges
for the door.
9. A security system according to claim 8 wherein the alarm is
located remote from the door; wherein the alarm is connected to a
reset switch located at the door; and wherein the alarm, once
energized, cannot be cancelled without operating the reset switch,
whereby security personnel must investigate the cause of the
alarm.
10. A security system according to claim 8 wherein the locking
means includes a dogging element which moves into and out of
engagement with the manually operable means, and a solenoid
connected with the dogging element for moving it.
11. In a security system for monitoring a door in a door frame, and
including a strike on the door frame and an alarm, an improved lock
comprising: a retractable latch bolt movable between extended and
retracted positions and normally urged to the extended position,
the latch bolt when in its extended position being projected beyond
the door for engagement with the strike to secure the door in a
closed position, the latch bolt when in its retracted position
being located beyond the strike so that the door is released from
the strike and can be opened; retracting means for moving the latch
bolt to its retracted position, the retracting means being manually
operated and including at least one handle which is grasped; a
dogging element movable independently of the retracting means
between engaged and disengaged positions and when in the engaged
position being engaged with the retracting means such that it
prevents operation of the retracting means, whereby the latch bolt
cannot be retracted with the retracting means; a solenoid connected
with the dogging element for moving the dogging element from one of
its positions to the other of its positions; a locking element
movable between blocking and release positions, the locking element
when in its blocking position preventing the latch bolt from moving
to the retracted position, the locking element when in its release
position permitting the latch bolt to move to its retracted
position, the locking element being held in its release position by
the latch bolt when the latch bolt is in its retracted position; an
auxiliary latch projecting beyond the door when the door is open
for engagement with the strike as the door is closed and being
depressed by the strike when the door is closed, the auxiliary
latch being connected with the locking element for holding the
locking element in its release position when the door is open and
the auxiliary latch is projected beyond the door, the auxiliary
latch when depressed permitting the locking element to move to its
blocking position; a first switch operated by the locking element
such that the switch condition changes with each movement of the
locking element between its release and blocking positions, the
switch being electrically connected with the alarm, whereby the
first switch monitors the position of the locking element; and a
second switch connected to the alarm and responsive to the position
of the dogging element so as to actuate the alarm when the dogging
element is disengaged.
12. A security system according to claim 11 further characterized
by a hinge having contactors on one leaf thereof and contacts on
the other leaf, the contactors engaging the contacts when the hinge
is closed; and wherein the switches are connected to the alarm
through the contacts and contactors of the hinge.
13. A security system according to claim 11 wherein the solenoid
has an axially shiftable armature and the second switch is aligned
with and operated by the armature.
14. A security system according to claim 11 further characterized
by a hinge mounting the door on the door frame, the hinge having
contacts on one leaf thereof and contactors on the other leaf, the
contactors engaging the contacts when the hinge is closed; and
wherein the two switches are connected to the alarm and the
solenoid is connected to a source of electrical energy through the
contacts and contactors of the hinge.
Description
BACKGROUND OF THE INVENTION
This invention relates in general to security systems and more
particularly to a security system wherein doors are controlled from
and monitored at a remote location.
Many buildings are too large for security personnel to effectively
patrol and as a result intruders often gain access to these
buildings and wander throughout them without being detected.
Indeed, forceable entries into buildings and intrusions into
restricted areas thereof represent a major problem for building
managers and security personnel, as well as law enforcement
agencies.
Heretofore, attempts have been made to remotely control door locks
from a central location, but most of these attempts have involved
incorporating electrically operated release mechanisms into the
lock strikes on door frames. In arrangements of this nature, the
strike jamb of the door frame must be specially prepared to
accommodate the release mechanism; and the special preparation is
usually quite expensive. Moreover, these devices release the door
once they are energized and as a result the door will swing open in
strong drafts. This is particularly hazardous in the event of a
fire since the door cannot be unlocked to permit trapped people to
escape and still be secured against opening in the presence of
drafts created by the fire. Hence, strike centered release
mechanisms contribute to the spread of fires. Also, strike centered
systems are easily violated.
Surveillance systems have also been developed for monitoring locks,
but these systems are also for the most part strike centered.
Hence, while they may provide some indication of the condition of
the electric release mechanism in the strike jamb, they provide no
indication as to the position of the door. Thus, the release
mechanism could be closed while the door is slightly ajar and the
monitoring system would not recognize the break in security.
Aside from the foregoing, the alarms of some monitoring systems can
be reset at the central location. This enables a lazy guard to
merely cancel an alarm without investigating the cause for the
alarm.
Finally, it should be noted that the best locks of current
construction utilize an auxiliary latch in lieu of a dead bolt to
prevent unauthorized opening of the lock with a plastic credit card
or some other thin device capable of being inserted between the
strike and the door. The auxiliary latch engages the strike and
depresses as the door closes and when depressed allows a locking
lever to fall behind the latch bolt. Thus, the latch bolt cannot be
forced back into the lock with a plastic credit card. The usual
practice for violating a lock of this nature is to place a piece of
adhesive tape over the auxiliary latch and latch bolt when the door
is open and then come back at some later time when the door is
supposed to be locked. Of course, the door will not be locked at
that time by reason of the adhesive tape, and thus access is gained
to the area which would otherwise be protected.
SUMMARY OF THE INVENTION
One of the principal objects of the present invention is to provide
a security system having electrically operated locks which can be
controlled from a remote location. Another object is to provide a
security system which monitors the positions of doors as well as
the condition of locks associated with the doors. A further object
is to provide a security system which monitors both the electrical
locking mechanism and the auxiliary latch of the lock. An
additional object is to provide a security system having an alarm
which cannot be cancelled without going to the door from which the
alarm originated. Still another object is to provide a lock having
auxiliary latching means to prevent unauthorized retraction of the
latch bolt and further having sensing means for sensing the
position of the auxiliary latching means and the locking mechanism.
These and other objects and advantages will become apparent
hereinafter.
The present invention is embodied in a security system having a
lock provided with sensing means which set off an alarm when a
security violation occurs at the door in which the lock is
installed. The invention is also embodied in a security system
wherein an alarm can only be cancelled at the location of the
security violation which caused the alarm to be energized. The
invention also consists in the parts and in the arrangements and
combinations of parts hereinafter described and claimed.
DESCRIPTION OF THE DRAWINGS
In the accompanying drawings which form part of the specification
and wherein like numerals and letters refer to like parts wherever
they occur:
FIG. 1 is a perspective view of a door provided with a lock and
contact hinge forming part of the security system of the present
invention;
FIG. 2 is a perspective view of the contact hinge;
FIG. 3 is a sectional view of the lock showing it in its locked
condition;
FIG. 4 is a sectional view similar to FIG. 3 but showing the lock
in its unlocked and open condition;
FIG. 5 is a schematic diagram of the electric circuit forming part
of the present invention;
FIG. 6 is a schematic diagram of a modified circuit; and
FIG. 7 is a sectional view of a modified lock in its locked
condition.
DETAILED DESCRIPTION
Referring now to the drawings (FIG. 1), D designates a door which
is hung on and swung away from a door frame 2 having a strike jamb
4 and a hinge jamb 6. The door D is actually hung on hinges 8 and
10 which are attached to the hinge jamb 6. The hinges 8 are
conventional full mortise hinges, while the hinge 10 which is also
a full mortise hinge, is a so-called contact hinge which completes
several electrical circuits when closed. The door D is provided
with a lock L, while the strike jamb 4 is fitted with a keeper or
strike 12 which the lock L engages and thereby prevents opening of
the door D.
The contact hinge 10 (FIG. 2) is disclosed in U.S. Pat. No.
3,659,063 and for purposes of this discussion it is sufficient to
note that the hinge 10, like the conventional hinges 8, has leaves
14 and 16, but that the leaf 14 has four contacts 18a, 18b, 18c,
and 18d, while the other leaf 16 has four spring loaded contactors
20a, 20b, 20c, and 20d which align with and engage the contacts
18a, 18b, 18c, and 18d, respectively, when the hinge 10 is closed.
However, when the hinge 10 opens the contacts 18 separate from
their respective contactors 20. The contacts 18 and contactors 20
are set in dielectric bushings 22 which insulate them from the
hinge leaves 14 and 16 and from one another. Thus, the hinge 10
when closed can complete four different electrical circuits.
The lock L is a standard mortise lock which is modified to enable
it to be locked or unlocked electrically from a remote location as
well as manually at the door D. It is also modified to enable it to
be monitored at the remote location. The basic lock illustrated in
the drawings (FIGS. 3, 4, and 7) is manufactured by The Corbin Lock
Co., but it should be recognized that locks of other manufacturers
may be utilized in the present invention.
The lock L (FIG. 3) includes a housing 30 to which a face plate 32
is attached. Both the housing 30 and face place 32 are recessed
into the door D, but the face plate 32 is flush with and exposed at
the narrow side face of the door D.
Mounted in the housing 30 is a latch bolt 34 which moves between a
retracted position, wherein it is contained entirely within the
housing 30 (FIG. 4), and an extended position, wherein a portion of
it projects outwardly beyond the face plate 32 (FIG. 3). When the
door D is closed and the latch bolt 34 is in its extended position,
the latch bolt 34 will project into an opening in the strike 12 and
prevent the door D from being opened. The latch bolt 34 is urged to
its extended position by a coil-type compression spring 36.
In addition to the latch bolt 34 the lock L is further provided
with an auxiliary latch 38 which pivots on the face plate 32 and is
normally urged outwardly beyond the face plate 32 by a spring
loaded auxiliary latch lever 40 (see dotted lines in FIG. 4). The
latch lever 40 pivots on the housing 30 and is urged against the
auxiliary latch by a spring 42. The auxiliary latch lever 40 in
turn operates a locking element or lever 44 which pivots on the
housing 30 about a pivot point 46 located adjacent to the rear wall
of the housing 30, and as it pivots it moves between a blocking
position, wherein it is disposed behind the latch bolt 34 (FIG. 3),
and a release position, wherein it is disposed above the latch bolt
34 and does not prevent the latch bolt 34 from moving to its
retracted position (FIG. 4). The locking lever 44 is urged to its
blocking position by a locking lever spring 48. The auxiliary latch
38, the auxiliary lever 40, the latch lever spring 42, the locking
lever 44 and the locking lever spring 48 constitute auxiliary
latching means and are all configured such that the locking lever
44 will be retained in its release position (FIG. 4) when the
auxiliary latch 38 is projected outwardly beyond the face plate 32,
but will be free to fall into its blocking position when the
auxiliary latch 38 is depressed (FIG. 3). Thus, when the door D is
open, the auxiliary latch 38 is projected beyond the face plate 32
and the locking lever 44 does not obstruct movement of the latch
bolt 34 to its retracted position (see dotted lines in FIG. 4).
However, as the door D is closed the latch bolt 34 first engages
the strike 12 and is cammed toward its retracted position, and
shortly thereafter the auxiliary latch 38 also engages the strike
12 and is moved inwardly into the housing 12. When the door moves
into its fully closed position the spring 36 drives the latch bolt
34 outwardly and into the opening in the strike 12. The auxiliary
latch 38, however, remains against the strike 12 and depressed. As
the latch bolt 34 moves toward the strike 12 and into its extended
position, the locking lever 44 falls downwardly to its blocking
position and blocks retraction of the latch bolt 34 (FIG. 3). Thus,
when the door D is closed, a credit card or other thin object
inserted between the lock face plate 32 and the strike 12 cannot
force the latch bolt 34 to its retracted position. The locking
lever 44 will prevent this. From the foregoing it is apparent that
the auxiliary latch 38 serves as the control element for the
auxiliary latching means comprised of the latch 38, the levers 40
and 44, and the springs 42 and 48.
In addition, the lock L has a cylinder 50 which when operated
pivots a cylinder lever 52 and the cylinder lever 52 in turn lifts
the locking lever 44 to its release position and further engages
the latch bolt 34 and moves it to its retracted position. Thus, the
lock L can be opened by inserting a key into the cylinder and
turning it.
The lock L has knobs 54 (FIG. 1) which are presented beyond the
front and back faces of the door and these knobs 54 are mounted on
a spindle 56 (FIG. 3) which extends through the door D as well as
through the lock housing 30. Indeed, the spindle 56 extends through
a spindle hub 58 within the housing 30, and this hub when rotated
by turning one of the knobs 54 operates a hub lever 60 which
engages the cylinder lever 52 and causes it to pivot as if it had
been pivoted by the cylinder 50. Thus, when one of the knobs 54 is
turned the locking lever 44 will likewise be lifted and the latch
bolt 34 retracted.
The spindle hub 58 has a notch 62 which opens toward the face plate
32 and normally aligns with a sliding dog 64 which is confined by
the housing 30 and face plate 32 and slides into and out of the
notch 62. Of course when the dog 64 is in the notch 62 (FIG. 3),
the spindle hub 58 cannot be turned and the latch bolt 34 cannot be
retracted by turning the knobs 54. However, when the dog 64 is
located beyond the notch 62, (FIG. 4) the spindle hub 58 is free to
rotate and the latch bolt 34 can be retracted by turning the knobs
54.
The sliding dog 64 further has a laterally projecting boss 66 which
is received in the bifurcated end of an operating lever 68 having a
pivot pin 70 projected from it intermediate its ends. The pivot pin
70 extends into and is confined by the housing 30, enabling the
operating lever 68 to pivot relative to the housing 30 and thereby
move the dog 64 into and out of the notch 62 in the hub 58. The
opposite end of the operating lever 68 is connected pivotally to a
draw member 72 which extends rearwardly through the back wall of
the housing 30. The outer end of the draw member 72 is connected to
the armature of a solenoid 74 which is mounted on the housing by
means of a bracket 76. The armature of the solenoid 74 is urged
outwardly toward the housing 30 by a spring 78, and when the
armature is so positioned, the draw member 72 positions the
operating lever 68 such that it holds the sliding dog 64 in the
notch 62 of the spindle hub 58. Thus, when the solenoid 74 is not
energized (FIG. 3), the spindle hub 58 cannot be rotated and the
latch bolt 34 cannot be retracted by turning the knobs 54. However,
when the solenoid 74 is energized (FIG. 4) the draw member 72 will
move rearwardly and cause the operating lever 68 to pivot about its
pin 70. This will move the dog 64 out of the notch 62 in the
spindle hub 58 so that the latch bolt 34 can be retracted by
turning one of the knobs 54. The sliding dog 64, the operating
lever 68, the draw member 72, and the solenoid 74 constitute a
locking mechanism which moves between locked and unlocked
positions.
The pivot point 46 of the locking lever 44 is adjacent to the back
wall of the housing 30, and near that pivot point the locking lever
44, in contrast to conventional locking levers, is provided with a
switch actuating tab 80 which projects upwardly along the back
wall. Directly opposite from the end of the actuating tab 80 the
back wall of the housing 30 is fitted with a microswitch 82 which
is operated by the switch actuating tab 80. When the locking lever
44 is in its blocking position, that is when it is behind the
latching bolt 34, the switch 82 is closed (FIG. 3). However, when
the locking lever 44 is raised to its release position, in which
case the latch bolt 34 is free to retract, the actuating tab 80
holds the switch 82 in its open position (FIG. 4).
The end wall of the solenoid 74 is fitted with another microswitch
84 which is operated by the armature of the solenoid 74. When the
armature is extended, in which case the locking mechanism is in its
locked condition so that the knobs 54 cannot be rotated (FIG. 3),
the switch 84 is closed. However, when the solenoid 74 is energized
and its armature is retracted, in which case the locking mechanism
is in its unlocked condition so that the knobs 54 are free to
rotate and thereby retract the latch bolt 34 (FIG. 4), the
microswitch 84 opens.
The two switches 84 and 82 are connected in series (FIG. 5) and the
series combination is connected by conductors 86 and 88 to the
contacts 18b and 18c on the leaf 14 of the contact hinge 10. The
conductors 86 and 88 are contained wholly within the interior of
the door D and therefore cannot be tampered with when the door D is
closed. The corresponding contactors 20b and 20c on the other leaf
16 of the hinge 10 are connected with a central control unit 90 in
a remote security room by means of conductors 92 and 94.
One terminal of the solenoid 74 is also connected to the conductor
88 leading from the hinge contact 18c, while the other terminal is
connected to a conductor 96 which passes through the interior of
the door D and is connected to the contact 18a on the leaf 14 of
the contact hinge 10. The corresponding contactor 20a on the other
hinge leaf 16 is connected by means of a conductor 98 to the
central control unit 90.
The central control unit 90 includes a switch which when closed
causes a current to flow through the conductors 98 and 96 to the
coil of solenoid 74, and thence through the conductors 86 and 94 to
the control unit 90. This current actuates the solenoid 74 and
causes the dog 64 to release the spindle hub 58 so that the knobs
54 can turn and retract the latch bolt 34 (FIG. 4). The current
passes through the hinge 10 at the contacts 18a and 18c and
contactors 20a and 20c.
In addition, the control unit 90 contains an alarm, which may be a
light, and this alarm is energized when the circuit containing the
two switches 82 and 84 is broken. This circuit includes the
conductors 92, 86, 88 and 94 as well as the hinge contacts 18b and
18c and the corresponding contactors 20b and 20c. Once the alarm is
energized by breaking the foregoing circuit, it will remain
energized even if the foregoing circuit is again completed. The
alarm is reset by closing a normally open reset switch 100 located
in the hinge jamb 6, and connected between the conductor 98 and
another conductor 102 leading back to the control unit 90. The
reset switch 100 is key operated so that only security personnel
with the proper key can cancel the alarm.
OPERATION
When it is desired to maintain the lock L in an unlocked condition
(FIG. 4), such as during working hours, the solenoid 74 is
energized from the control unit 90. This causes the dog 64 to move
out of the notch 62 in the spindle hub 58 and to remain out of that
notch. In other words, energizing the solenoid 74 moves the locking
mechanism to its unlocked condition. Consequently, the knobs 54 are
free to turn and anyone desiring to pass through the door opening
need only turn one of the door knobs 54 and then open the door D.
Of course, when the door knob 54 is turned the latch bolt 34 is
retracted and this frees the door D to swing outwardly on its
hinges 8 and 10. It is significant to note, however, that even when
the locking mechanism is in its unlocked condition, the latch bolt
34 still projects into the strike 12. Hence, the door D cannot be
blown open by fire-induced drafts as is the case with strike
centered release arrangements.
After working hours, the door D is secured by the lock L and is
further monitored at the central control unit 90. In particular,
the solenoid 74 is de-energized, and the solenoid spring 78, acting
through the draw member 72 and operating lever 68, causes the
sliding dog 64 to enter the notch 62 in the spindle hub 58 (FIG.
3). This prevents the hub 58 from rotating which in turn prevents
the latch bolt 34 from being retracted. Anyone attempting to
retract the latch bolt by slipping a thick piece of plastic or
other material between the face plate 32 of the lock L and the
strike 12 will be foiled, since the locking lever 44 is positioned
behind the latch bolt 34, preventing its retraction.
If at the close of working hours the door D is left open, the
electrical circuit through the door D will be broken at the
contacts 18b, and 18c and the contactors 20b and 20c of the contact
hinge 10, and the control unit 90 will signal an alarm.
On the other hand, should a piece of adhesive tape be placed over
the latch bolt 34 and the auxiliary latch 38 to hold them both in
their retracted positions after the door D is closed, or if the
latch bolt 34 and auxiliary latch 38 are held in their retracted
position in some other unauthorized manner, the locking lever 44
will remain in its release position. In that position its actuating
tab 80 holds the microswitch 82 open so that the electrical circuit
through the door D is broken at the microswitch 82. Again, the
alarm sounds.
If only the auxiliary latch 38 is depressed in some unauthorized
manner, such as by a piece of adhesive tape, then the locking lever
44 will drop to its blocking position and prevent movement of the
latch bolt 34 to its fully retracted position. Consequently, the
door D cannot be fully closed and the alarm circuit will be broken
at the contacts 18b and 18c and the contactors 20b and 20c of the
contact hinge 10.
If the solenoid 74, the draw member 72, the operating lever 68,
sliding dog 64 or spindle hub 56 jambs or otherwise fails to move
in such a manner that the dog 64 enters the notch 62 in the spindle
hub 58, then the solenoid armature will remain retracted and hold
the microswitch 84 in its open position. Thus, the alarm circuit
will be broken at the switch 84 and the alarm in the control unit
90 will be energized. In other words, if the locking mechanism
fails to lock the spindle hub 58 against rotation, then the switch
84 will be open and the alarm will be energized.
In summary, an alarm will sound at the remote control unit 90 if
any of the following breaks in building security occur at the door
D:
1. the door fails to close completely;
2. the latch bolt 34 is in some unauthorized manner held in its
retracted position;
3. the auxiliary latch 38 is in some unauthorized manner held
depressed; or
4. the locking mechanism which locks the door knobs 54 against
rotation jambs or otherwise malfunctions.
Once the alarm is energized at the control unit 90, it cannot be
cancelled at the control unit 90. On the contrary, the reset switch
100 on the hinge jamb 6 must be closed, and this requires the
presence of security personnel at the door D. Thus, the security
personnel must investigate the cause for the alarm.
In most buildings a plurality of doors D are controlled and
monitored from the control unit D, and these doors are usually
located at key locations such as at the entrances to stairwells or
at the entrances to restricted areas.
MODIFICATIONS
In lieu of being connected in series the switches 82 and 84 may be
connected in parallel across the conductors 86 and 88 (FIG. 6). In
that case the switch 82 should be open when the locking lever 44 is
in its blocking position and should close when the locking lever 44
moves to its release position. The switch 84, on the other hand
should close when the locking mechanism is open and the knobs 54
are thereby free for rotation. However, when the locking mechanism
is in its locked position, and the knob 54 cannot rotate, the
switch 84 is open. In addition, the hinge 10 is provided with a
switch 110 which is held open while the hinge 10 is closed, but
closes when the hinge 10 opens. The switch 110 is connected across
the conductors 94 and 92. Such a hinge is described in the United
States patent application of Francis C. Peterson, Ser. No. 175,594,
filed Aug. 27, 1971. Finally, the remote control unit 90 is
constructed such that the alarm thereof is energized when the
conductors 92 and 94 are shorted. This occurs when the door D
opens, and the switch 110 closes, or when the door D is closed and
either one of the switches 82 or 84 is closed.
By joining the dog 64, the operating lever 68, and the draw member
72 into a unitary structure or operating member 120 (FIG. 7) which
slides to and fro with the armature of the solenoid 72, the knobs
54 are locked against rotation when the solenoid 74 is energized
and are free to rotate when the solenoid 74 is de-energized. In
such a case the microswitch 84 should be such that it closes when
the solenoid 74 is energized and the knobs 54 are locked against
rotation and opens when the locking mechanism moves ot its release
position, provided the switches 81 and 84 are wired in series.
This invention is intended to cover all changes and modifications
of the example of the disclosure which do not constitute departures
from the spirit and scope of the invention.
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