U.S. patent number 3,893,095 [Application Number 05/474,884] was granted by the patent office on 1975-07-01 for alarm device for indicating the removal of a fire extinguisher.
Invention is credited to Dennis E. DeJong.
United States Patent |
3,893,095 |
DeJong |
July 1, 1975 |
Alarm device for indicating the removal of a fire extinguisher
Abstract
The weight of a fire extinguisher depresses a first plunger
which in turn maintains a second plunger retracted so as to hold
open or deenergize an alarm. When the fire extinguisher is removed,
the first plunger moves upwardly out of its obstructive or
interfering relation with the second plunger so that the second
plunger advances from its retracted position to energize or
activate the alarm. Once the alarm is triggered into operation, a
slidable drawer must be unlocked and pulled open to reset the
alarm.
Inventors: |
DeJong; Dennis E. (Princeton,
MN) |
Family
ID: |
23885339 |
Appl.
No.: |
05/474,884 |
Filed: |
May 31, 1974 |
Current U.S.
Class: |
169/23; 340/289;
340/666; 340/568.8 |
Current CPC
Class: |
G08B
13/14 (20130101) |
Current International
Class: |
G08B
13/14 (20060101); G08b 013/14 () |
Field of
Search: |
;340/272,280,289
;169/23,51 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Swann, III; Glen R.
Attorney, Agent or Firm: Peterson; Stuart R.
Claims
I claim:
1. An alarm device for indicating the removal of a fire
extinguisher therefrom comprising a casing having an opening at the
front, a drawer slidably received in said casing having a front
wall for blocking said casing opening, an electric alarm in said
drawer, a switch in circuit with said alarm, a horizontally
reciprocal plunger for opening said switch in a first position
thereof to inactivate said alarm and closing said switch in a
second position thereof to activate said alarm, means biasing said
plunger into said second position, a vertically reciprocal plunger
extending downwardly through the top of said casing to a first
position to retain said horizontal plunger in its first position,
means biasing said vertical plunger upwardly to a second position
to permit said horizontal plunger to assume its second position,
and means for locking said drawer in said casing, whereby when a
fire extinguisher is supported on said casing said vertical plunger
is depressed sufficiently by said fire extinguisher to keep said
horizontal plunger in its said first position and when said fire
extinguisher is removed said horizontal plunger moves to its said
second position.
2. An alarm device in accordance with claim 1 in which said casing
includes top, side, rear and bottom walls, and said drawer includes
front, side and bottom walls, said drawer being open at the top and
rear.
3. An alarm device in accordance with claim 2 in which the rear
wall of said casing extends upwardly to provide an upstanding
mounting wall, and means on said mounting wall for releasably
holding a fire extinguisher in position on said top wall so as to
depress said vertical plunger.
4. An alarm device in accordance with claim 3 including a sleeve
secured at its upper end to said top wall and extending downwardly
into said casing for guiding said vertical plunger, the lower end
of said sleeve terminating at an elevation above the reciprocal
path traversed by said horizontal plunger.
5. An alarm device in accordance with claim 3 in which the bottom
wall of said drawer and the bottom wall of said casing each have
slots therein which are in alignment when said drawer is within
said casing, and said lock means includes a latch member rotatable
downwardly into said openings when aligned to effect the locking of
said drawer within the casing.
6. An alarm device in accordance with claim 5 in which said alarm
comprises an upwardly facing speaker, said top wall having a
plurality of holes therein so that the sound from said speaker can
pass through said casing when said alarm is actuated.
7. An alarm in accordance with claim 1 including means in said
drawer for connecting a battery in circuit with said alarm and
switch.
8. An alarm device for indicating the removal of a fire
extinguisher comprising a casing including top, side, rear and
bottom walls, said casing having a front opening a vertically
reciprocal plunger extending downwardly through said top wall into
said casing, said plunger being located near said rear wall, spring
means normally biasing said plunger upwardly to raise the lower end
of said plunger within said casing, a drawer slidably received in
said casing having a front wall for blocking said casing opening, a
horizontally reciprocal plunger carried in said drawer, spring
means biasing said horizontally reciprocal plunger toward said
vertically reciprocal plunger, said horizontal plunger engaging the
lower end of said vertical plunger as said drawer is moved into
said casing when said vertically reciprocal plunger is depressed by
a fire extinguisher, a switch actuatable into closed position by
said second biasing means when the lower end of said vertically
reciprocal plunger rises under the influence of said first biasing
means, an electric alarm means in circuit with said switch, said
electric alarm means being energized when said switch is closed,
and lock means for preventing removal of said drawer from said
casing, whereby when the fire extinguisher is removed the vertical
plunger rises sufficiently to permit said horizontal plunger to
advance therebeneath and close said switch, said horizontal plunger
then underlying said vertical plunger so that said vertical plunger
cannot then be depressed again until said lock means is unlocked
and said drawer pulled sufficiently open to permit said vertical
plunger to move downwardly without interference from said
horizontal plunger.
9. An alarm device in accordance with claim 8 in which said drawer
has only bottom and side walls in addition to said front wall, said
casing top wall having at least one hole therein, and said electric
alarm means including a speaker disposed beneath said one hole when
said drawer is received in said casing.
10. An alarm device in accordance with claim 9 in which said bottom
walls have aligned slots when said drawer is received in said
casing and said lock means includes a latch arm rotatable into said
aligned slots to lock said drawer in said casing.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to fire extinguishers, and
pertains more particularly to an alarm device that is automatically
sounded when the fire extinguisher is removed from the device.
2. Description of the Prior Art
Various alarm devices have been used in the past in conjunction
with glass paneled doors containing the fire extinguisher. When the
door is opened, the alarm is sounded. The weight of the
extinguisher plays no role in this type of protective
arrangement.
SUMMARY OF THE INVENTION
A primary object of the invention is to effectively thwart the
unauthorized removal of fire extinguishers. In this regard, an aim
of the invention is to provide an alarm that is triggered into
operation when the fire extinguisher is taken but which alarm
cannot be inactivated or reset by the person removing the fire
extinguisher.
Another object of the invention is to provide an alarm device that
can be reset only by an authorized person, the resetting operation
first requiring the unlocking of a slidable drawer.
Still another object is to provide an alarm device that is
completely self-contained, there being no external wiring or any
parts that can be manipulated or detached by unauthorized
persons.
Another object is to discourage the taking of a fire extinguisher
by reason of it being apparent that an alarm is associated with the
casing supporting the fire extinguisher, this being due to the
visibility of the face of the lock and the keyhole therein.
Another object is to provide an alarm device that will not
interfere with the removal of the fire extinguisher when actually
needed to extinguish a fire.
Yet another object of the invention is to provide an alarm device
that will accommodate various sizes of fire extinguishers.
Another object is to audibly signal the unauthorized taking of the
fire extinguisher without having to modify in any way the fire
extinguisher being protected.
Still another object of the invention is to provide an alarm device
that is versatile as to its manner of mounting in that it can be
mounted directly on a building wall or located within a cabinet
that is mounted on the wall.
A further object of the invention is to provide an alarm device
that will be relatively inexpensive to manufacture, thereby
encouraging its widespread use.
Briefly, my invention comprises a casing having top, sides, rear
and bottom walls but open at the front. Toward the rear of the top
wall is located a vertically reciprocal plunger, the plunger being
biased upwardly by a coil spring. When the fire extinguisher is
placed on the casing, then the plunger is depressed. A slidable
drawer is insertable through the front opening, the drawer having a
front wall that then blocks the casing opening. A second plunger is
mounted in the drawer for horizontal reciprocation, being spring
biased toward the first plunger. When the first plunger is
depressed by a fire extinguisher, then the second plunger is held
in a retracted or cocked position to keep a switch open, thereby
deenergizing or inactivating the alarm. When the first plunger is
permitted to move upwardly, which it does when the fire
extinguisher is removed, then the second plunger advances so as to
close the switch and thus trigger or energize the alarm.
A cylinder lock is mounted on the front wall of the drawer. The
lock has a latch member thereon which is key-rotated into a
downwardly extending position, the latch member then passing
through aligned holes, one being in the bottom of the drawer and
the other in the bottom wall of the casing. Thus, in order to reset
the alarm, it is necessary to first unlock the drawer, pull the
drawer out, depress the first plunger (by placing a fire
extinguisher thereon), and then sliding the drawer back into the
casing to produce the retracted or cocked condition of the second
plunger.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a side elevational view of my alarm device with a
conventional fire extinguisher supported thereon;
FIG. 2 is a perspective view of the device itself, the fire
extinguisher having been removed;
FIG. 3 is a vertical sectional view taken generally in the plane of
the plunger and key of FIG. 2 but with the fire extinguisher of
FIG. 1 thereon, only the lower portion thereof, however, being
illustrated;
FIG. 4 is a schematic view showing the manner in which the alarm is
maintained in an inactive or cocked state, and
FIG. 5 is a schematic diagram showing the alarm after it has been
activated or triggered into operation.
DESCRIPTION OF THE PREFERRED EMBODIMENT
My alarm device has been designated generally by the reference
numeral 10. The exemplary device 10 includes an upstanding mounting
panel 12 at the rear thereof having four holes 14 therein. As can
be understood from FIG. 1, the holes 14 accommodate screws 16 which
extend into the wall labeled 18. Various ways of attaching the
panel 12 can be employed, the screws 16 being a simple expedient
that permits a facile illustration thereof.
The mounting panel 12 has a pair of vertically spaced spring clips
20, the clips 20 being anchored to the mounting panel 12 by rivets
22. The function of the clips 20, as is believed evident, is to
releasably hold in place a conventional fire extinguisher 24.
At the lower end of the mounting panel 12 is a retangular casing 26
composed of a top wall 28, spaced side walls 30 and a bottom wall
32. The rear wall 34 is merely a downward extension of the mounting
panel 12. The casing 26 has an opening 36 at its front end.
A hole 38 is provided in the top wall 28 at a location near the
rear of the casing 26. Having its upper end secured to the top wall
28, such as by brazing, is a downwardly depending sleeve 40 having
an inturned flange 42 at its lower end. Vertically reciprocal in
the sleeve 40 is a plunger 44 having an enlarged head 46 at its
upper end, the plunger 44 being of sufficient length so as to
project beyond the lower end of the sleeve 40 when depressed, as
can be discerned from FIG. 3. Contained in the sleeve 40 is a coil
spring 48, the lower end of the coil spring 48 bearing against the
inturned flange 42 and the upper end of the coil spring 48 bearing
against the underside of the enlarged head 46. In this way, the
plunger 44 is biased upwardly, the weight of the fire extinguisher
24 overcoming the biasing action of the spring 48 to cause the
plunger 44 to assume the raised position appearing in FIG. 2.
Removably received in the casing 26 is a slidable drawer denoted
generally by the reference numeral 50. The drawer 50 has a front
wall 52 which blocks the opening 36, spaced side walls 54, a bottom
wall 56, but no top or rear wall. Secured to the bottom wall 56 of
the drawer 50 is a U-shaped metal bracket 58 comprised of
horizontal flanges 60 at each end, upwardly extending end walls 62,
64 and a horizontal top panel 66. The flanges 60 are welded or
otherwise secured to the bottom wall 56 of the drawer 50.
A switch unit 68 is mounted to the wall 62 of the U-shaped bracket
58. To effect the mounting, the switch unit 68 has a threaded
bushing 70, there being a nut 72 and a nut 74 to either side of the
wall 62 which is apertured so that the bushing 70 is fastened in
place. The switch unit 68 also includes a plastic housing 76, the
bushing being anchored thereto by a retainer 77. Mounted for
horizontal reciprocal movement through the bushing 70 is a plunger
78 having an enlarged head 80. To simplify the drafting, the
plunger 78 has been shown with a metal washer 82 adjacent its head
80, the washer being movable with the plunger 78 to bridge a pair
of fixed contacts 84. There is a coil spring 86 contained within
the housing 76 that normally biases the plunger 78 to the left as
viewed in FIG. 3, one end of the spring 86 bearing against the head
80 and the other end against the housing 76.
It should be evident from FIG. 3 that when the plunger 44 is
depressed, then the plunger 78 is held in a retracted position and
the switch unit 68 is open because the contacts 84 are not at this
time bridged by the metallic washer 82. However, when the plunger
44 rises, then the plunger 78 is advanced under the influence of
the spring 86 to bridge the contacts 84. The contacts 84 have
conductors 88, extending to a pair of bayonet type terminals 90 and
92 which project from the housing 76.
The terminal 90 is mated with a slip-on terminal 94 having a
conductor 96 extending to a small contact battery terminal board
98. The battery terminal board 98 has a pair of snap-on terminals
100, 102, one being a male terminal and the other a female terminal
so as to accommodate the terminals on a conventional 9 volt battery
104, such as is customarily used to power transistor radios.
Whereas the conductor 96 is connected to the terminal 100 of the
small board, the other terminal 102 has a conductor 106 extending
to one side of a high pitched electromagnetic alarm 108, comprising
a speaker, speaker supported on the top panel 66 of the bracket 58,
a portion 108a of the speaker extending downwardly through a
circular opening in the panel 66. The other terminal 92 on the
switch unit 68 is mated with a slip-on terminal 110 having a
conductor 112 extending to a screw 114 that is attached to the top
panel 66 of the U-shaped bracket 58. The panel 66 itself is
connected to the other side of the alarm 108. Consequently, when
the contacts 84 are bridged by the washer 82, a circuit is
completed from the battery 104 through the contacts 84 and the coil
of the speaker 108.
In order to prevent the unauthorized removal of the drawer 50, the
front wall 52 thereof has a cylinder lock 116 mounted therein. The
lock 116 has an escutcheon plate or flange 118 that confronts the
forward side of the front wall 52. Confronting the back side of the
front wall 52 is a nut 119, the exterior of the lock's barrel 120
being threaded for the accommodation of the nut 119. The rear end
of the plug 122 rotatable in the barrel 120 has mounted thereon a
latch member 124 that can be rotated between a horizontal position
in which it is completely within the confines of the drawer 50 to a
vertical position (FIG. 3) where it extends downwardly through a
transverse slot 126 in the bottom wall 56 of the drawer 50 and an
aligned slot 128 in the bottom wall of the casing 26. When
extending vertically down through the two slots 126, 128, the
drawer 50 is locked within the casing 26 and cannot be removed
until the latch member 124 is rotated upwardly into a horizontal
position so as to permit the drawer 50 to be pulled outwardly. A
key 129 is shown which locks and unlocks the cylindrical lock 116.
When the drawer 50 is fully inserted, as indicated in FIG. 3, the
speaker 108 assumes a position directly beneath a cluster of holes
130 (FIG. 2) formed in the top wall 28 of the casing 26 so that the
sound from the speaker 108 can pass upwardly and outwardly into the
surrounding area.
Operation
The manner in which my alarm device 10 functions is extremely
simple. It will perhaps be the easiest to refer to FIGS. 4 and 5
for the operational sequence. In FIG. 4, the vertically reciprocal
plunger 44 is held depressed by reason of the weight of the fire
extinguisher 24. Thus, the positional relationship appearing in
FIG. 4 corresponds to that of FIG. 3. The arrow 132 in FIG. 4
indicates the direction of the biasing action supplied by the coil
spring 48 shown in FIG. 3. The other arrow 134 signifies the
biasing action supplied by the coil spring 86 of FIG. 3. It will be
obvious that the depressed plunger 44 is in an obstructive or
interfering relation with the plunger 78, thereby holding the
plunger 78 in a retracted or cocked position so that the plunger 78
cannot move in the direction of the arrow 134. Stated somewhat
differently, the two plungers 44, 78 are mounted for axial movement
along two mutually intersecting paths.
However, when the plunger 44 moves upwardly in the direction of the
arrow 132 shown in FIG. 4, it reaches the upper position
illustrated in FIG. 5, which position also appears pictorially in
FIG. 2. This condition happens when the fire extinguisher 24 is
removed from the top wall 28 which functions as a supporting
platform for the extinguisher 24. As soon as the plunger 44 moves
upwardly, then the plunger 78 can advance rearwardly in the
direction of the arrow 134 appearing in FIG. 4. The two plungers
44, 78 thus assume the relative positions illustrated in FIG. 5. It
is important to note that the contacts 84 at this time are bridged
by the metal washer 82, thereby closing the circuit to the alarm
108, power flowing from the battery 104 through the alarm 108 so
that a high pitch sound is produced.
The sound emitted by the alarm 108 emanates upwardly through the
cluster of holes 130 in the top wall 28 of the casing 26. There is
no top wall to the drawer 50 so there is a clear avenue of escape
as far as the sound is concerned. The audible alarm thus serves as
a warning to anyone in the vicinity that the fire extinguisher 24
has been removed.
While the proper removal of the fire extinguisher 24 also sets off
the alarm, if a fire has indeed occurred, then the highly audible
signal additionally performs the important function of warning
people in the vicinity that a fire has occurred. If the removal is
unauthorized, such as by a vandal or thief, then the sounding of
the alarm calls attention to this act. Consequently, my invention
will find especial utility in various public buildings,
particularly schools, where passers-by are apt to be present and
would automatically take note of the unauthorized removal. On the
other hand, if my device is installed in an apartment house or
office building, even though someone is not present at that time
when the fire extinguisher 24 is being removed, nonetheless the
sounding of the alarm arouses the tenants or occupants in the area,
resulting in an immediate investigation.
Although it is believed evident from FIG. 3, FIG. 5 indicates that
once the vertical plunger 44 has moved upwardly and the horizontal
plunger 78 has advanced horizontally therebeneath, the vertical
plunger 44 cannot thereafter be depressed. More specifically, the
plunger 78 has moved beneath the plunger 44 so that any attempt to
depress the plunger 44, such as to turn off the alarm, will not be
successful because the lower end of the plunger 44 will simply
strike the now released plunger 78.
Therefore, my device 10 will remain in a cocked position as shown
in FIGS. 3 and 4 until the fire extinguisher 24 has been removed.
This causes a triggering of the alarm by reason of the closing of
the switch unit 68 in that the contacts 84 are now bridged by the
washer 82. The switch unit 68 is literally latched closed by reason
of the inability to redepress the vertical plunger 44 to the
obstructive relation between it and the plunger 78 so that the
alarm continues to sound until someone having the key 129 arrives
so as to reset the alarm. In the meantime, any act of vandalism or
thievery with respect to the fire extinguisher 24 is brought to the
attention of others who are present in the vicinity.
It should be apparent that the unlocking of the drawer 50 through
the agency of the key 129 causes the latch member 124 to be moved
out of the position depicted in FIG. 3. When in the position of
FIG. 3, the latch member 124 extends downwardly through the two
slots 126, 128 so that the drawer 50 cannot be removed because the
latch member 124 engages the bottom wall 32 of the casing 26 at the
right side of the slot 128. When rotated upwardly, though, the
latching member 124 no longer extends downwardly into the slot 128
and the drawer can be pulled forwardly or to the right as viewed in
FIG. 3, the key 129 serving as a pulling expedient when partially
turned.
When replacing the drawer 50 in the casing 26, it should be noted
that with the fire extinguisher 24 depressing the plunger 44, the
inward movement of the drawer 50 causes the horizontally reciprocal
plunger 78 to abut against the depressed plunger 44 so as to cause
the spring 86 to be progressively compressed as the drawer 50 is
moved inwardly. Of course, the obstruction or interference created
by the depressed plunger 44 keeps the plunger 78 from advancing
with the drawer 50 once it engages the plunger 44. Such an
occurrence moves the washer 82 away from the contacts 84 as clearly
illustrated in FIG. 3 (and also in FIG. 4). Hence, when the drawer
50 is inserted under these conditions, the alarm is reset or cocked
and is in continued readiness should the fire extinguisher 24 again
be removed.
* * * * *