Improvements in Burglar Alarms.
Year: 1890

page_text: Date of Application, 4th Dec., 1890
Complete Specification Left, 14th July, 1891-Accepted, 12th Sept., 1891
PROVISIONAL SPECIFICATION.
Improvements in Burglar Alarms.
A communication from CHARLES CASSAT DAVIS, of Los Angeles, State of
California, United States of America, Attorney-at-Law.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., do hereby declare the nature of this invention to be as follows:-
This invention relates to that class of alarms in which a blade is made to enter
the crevice between a door or window and its casing and in which mechanism is
arranged to continuously sound an alarm for a protracted period after the door or
window is opened.
This burglar alarm comprises a bell mounted upon a bell post which is fixed to a
main master blade in which is journalled the driving arbor or shaft, one end of
which extends into the chamber of the bell and is operatively connected with the
alarm-operating mechanism. On the free end of the driving arbor is secured an
auxiliary or winding blade.
The alarm-operating mechanism is driven by a main spring operatively connecting
the driving arbor with the master blade.
In practice the spring is wound by rotating the auxiliary blade, then the auxiliary
blade and master blade, which are thin and wedge shaped, are brought into the
same plane edgewise and their free ends are then inserted in the crack between the
door and its casing or between the two sashes of the window or between the sash
and the casing as the case may be. The friction of the wedge or the expansive
force of the spring holds the devices in place until the door or window is opened.
When the door or window is opened, the blades are released and the spring is
thereby allowed to uncoil to rotate the arbor and sound the alarm.
Dated this 4th day of December 1890.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Burglar Alarms.
A communication from CHARLES CASSAT DAVIS, Attorney-at-Law, of Los
Angeles, County of Los Angeles, State of California, United States of
America.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., do hereby declare the nature of this invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention relates to that class of alarms in which a blade is arranged to
enter the crevice between a door or window and its casing and in which mechanism
s arranged to continuously sound an alarm for a protracted period after the door or
window is opened.
The object of the invention is to simplify, reduce in size and to cheapen such
levices and to avoid the necessity of a separate winding key which might become
ost.
Also to so construct the device that its operation does not depend upon the action
of trigger mechanism, and yet to allow the device to be removed by one within the
house without sounding the alarm

page_text: The invention is capable of being embodied in various forms, and is illustrated in
the accompanying drawings in which Figs. 1,.2, 3, 4, 5 and 6 illustrate a form in
which the mechanism is partly exposed, and Figs. 7, 8 and 9 illustrate a form
in which the mechanism is concealed. This latter form is deemed most desirable
as it is more compact, has fewer parts and is so constructed that when the master
blade and winding blade are inserted into the crevice or cracks between the door
and its jamb, the alarm will lie flat against the door or frame as is most convenient,
and so be out of the way of any one in the room.
It is also so. constructed and the blades are so arranged with relation to each
other that the action of the alarm operating spring will cause such blades to fill and
clutch in any ordinary crack and so hold the alarm in position, irrespective of the
size of the crack in which such blades are inserted.
In the accompanying drawings,
Fig. 1 is a plan view of the cruder form of this alarm in place with its blades
between the door and the door frame, the top of the bell being cut away to expose
the mechanism.
Fig. 2 is a side view of the alarm in place, a portion of one side of the bell being
broken away to expose the mechanism.
Fig. 3 is a view of the under side of the end of blade M shown in Fig. 2. This
figure is designed to show the flaring hole a.
Fig. 4 illustrates the connection of the blade M and main spring Q.
Fig. 5 is a fragmentary view illustrating a modified form of connection between
the spring and blades.
Fig. 6 shows a further modification of the same.
Fig. 7 is a plan view of the preferred form with a portion of the bell removed to
expose the mechanism.
Fig. 8 is a plain side view of said preferred form with a portion of the bell
removed to expose the mechanism, and showing the blades in position for insertion
in the crack or crevice.
The invention comprises the combination of a master blade; alarm operating
mechanism; a driving arbor journaled to the master blade and operatively connected
with the alarm operating mechanism; a main-spring operatively connecting the
arbor with the master blade, and a winding blade secured to the arbor, said master
blade and winding blade being adapted for insertion in the crevice between the door
and jamb.
I will first describe the form of the invention shown in Figs. 1 to 6.
A is the main or master blade, to one end of which is fixed the bell post B upon
which is mounted the bell D. The driving arbor or shaft E is journaled in the
master blade A and one of its ends extends into the chamber of the bell and is
operatively connected with the alarm operating mechanism. The means preferably
employed to operate the alarm consist of the ratchet wheel F fixed upon the end of
the driving arbor, the spur wheel G journaled upon such arbor and operatively
connected by pawls H with the ratchet wheel F, so that the rotation of the arbor
in one direction will be free while its rotation in the other direction will drive the
spur wheel G which meshes with pinion I fixed to and co-axial with escapement
wheel J, which, with said pinion, is journaled to revolve on the bell post B to
operate the bell hammer K through the pallet L to which the hammer is attached.
On the free end of arbor E is secured the secondary-auxiliary, or winding blade M.
In the form shown in Figs. 1 and 2, this blade is journaled upon the arbor, but it
may be fixed upon the arbor as shown in Fig. 5 and rotate therewith.
In the forms shown in Figs. 2 and 6, the arbor is also provided with the rigid
main-spring holding arm N, to which the outer end of the main spring is attached,
arranged to be engaged by a projection of the auxiliary blade M.
In Fig. 1 this projection is simply a lug O, in Fig. 6 it is formed by a spring
pressed pin O, the normal position of which is a depressed position, as hereinafter
explained.
The alarm operating mechanism is driven by the main spring Qoperatively

page_text: connecting the arbor with the master blade. It is preferred to so connect the
spring with the master blade as to allow it to be thrown out of such connection at
pleasure.
On the arbor, between the arm N and the master blade A, is journaled a sleeve P
to which is fixed the coiled spring Q.
-
Means
The end of the sleeve next the master blade A is provided with serrations
or teeth R to engage corresponding serrations R' in the face of blade A.
are provided for holding the sleeve and blade in operative contact and for
throwing the sleeve out of such contact. To the blade A is pivoted a spring-
pressed lever S which engages the walls T of a groove to hold the serrated
end of the sleeve in contact with the serrations in the blade. These serrations
are arranged to hold the inner end of the spring stationary while the spring is
coiled or wound up by the revolution of blade M.
In practice the spring is wound by rotating the blade M while its projection O
or equivalent is in contact with arm N as shown in Figs. 2, 4 and 6, then the
two blades are brought into the same plane edgewise and their thin wedge-
shaped free ends are then inserted in the cracks between the door and its
casing, or between the two sashes of the window, or between a sash and the
window frame, as the case may be. The friction of the wedge, or the expansive
force of the spring holds the device in place until the door or window is opened.
When the door is opened, the blades are released and the spring is thereby
allowed to uncoil to rotate the arbor E. In the form shown in Fig. 5, (7, 8 & 9)
the uncoiling of the spring rotates the arbor E and also the blade M fixed
thereto; but in the other forms shown, the blade does not rotate with the
arbor, while the spring uncoils. In the form of device shown in Fig. 2, the
hole a through blade M through which the arbor passes is made flaring in its
outer portion, in the direction of the length of the blade and toward the free
end thereof as shown by Fig. 3 and also by dotted lines in Fig. 2, so that
when free, the outer end of the blade can be drawn away from the arm N to
remove the lug O from the path of the arm, thus allowing the arm to rotate
without rotating the blade.
In order to secure the movement of the blade M necessary to withdraw the lug O
from the path of arm N, the blade spring b is provided arranged to press the free
end of the blade away from the arm N. This spring is preferably arranged with
one end in engagement with a flange or collar e around the arbor E, and with the
other arm in operative engagement with the blade M to throw its free end away
from arm N. In the drawing Fig. 2, this spring is shown fixed to blade M by a
screw h.
Fig. 6 shows other means for operatively connecting and disconnecting the
auxiliary blade M and the main spring holding arm N and releasing the auxiliary
blade from the action of the spring when the arms are released by the opening of
the door or window. In this drawing a spring-pressed auxiliary, movable stud O'
Pis mounted in the blade and normally pressed away from the arm N by a spring d,
so that the blade M is normally free to revolve upon arbor E on which it is
journaled. In practice, when it is desired to wind the spring, the stud is pressed
into the position shown in the drawing, and by rotation of the blade is brought into
contact with the edge of the arm N to wind the spring. When pressed against the
arm N in winding the spring, the friction between the arm and lug caused by the
tension of the spring Q, prevents the lug from being forced out by its spring d,
(suggested by dotted lines in Fig. 6), and this friction continues until the blades
are again released, then the spring d drives the stud O' out of contact with arm N,
which is then left free to revolve without moving blade M.
W represents a portion of a cord by which the device can be secured to the door
knob or to a nail, so that it will swing suspended when not in use or when released
by the opening of the door or window, thus allowing the bell to sound clearly
without being deadened by contact with the floor.
If desired, a wire netting may be provided attached to the master blade and

page_text: its sound.
ше ben to nola it free from contact with objects which might deaden
If it be desired to remove the device without sounding the alarm, lever S is pressed.
thus withdrawing teeth R of the sleeve from contact with teeth R' of blade A, and
allowing sleeve P to revolve with the uncoiling of the main spring. The main
spring is made sufficiently conoidic to allow the sleeve to be moved out of and into
contact with blade A.
In Figures 7, 8 and 9 the apparatus is much more convenient than that just
described.
In the improved form, a plate or base A' is provided, which is a flat circular
shaped piece of metal or other suitable material, approximately equal in diameter
to the mouth of the alarm bell D.
In the centre of this base A' is secured the bell post B, upon which post is
mounted the bell D. To such base is also secured the frame a, in which is journaled
the upper ends of the alarm mechanism, the lower ends of such mechanism being
journaled in the base A¹.
The driving arbor or shaft E is journaled in the frame and base plate or master
blade A and the winding blade M is secured thereto through the medium of the
winding arm M¹ fixed to the projecting end of such arbor, and is arranged substan-
tially axially parallel with the arbor. To the upper end of this arbor is secured
the inner end of the main-spring Q, the outer end of which spring is fixed to the
frame a.
The driving arbor E is operatively connected with the alarm mechanism by
suitable means such as those employed in the alarm shown in Figs. 1 and 2.
The securing blade, or member A" of the base, or master blade is hinged or
otherwise attached to the base A' and is arranged to project into a plane tangent to
the path of the member M of the winding blade, and the blades are arranged with
their width tangential to such path, so that when the winding blade is brought into
the proper position for insertion into the crack between the door and the jamb, the
width of the two blades will be in the plane of such tangent, as shown in Fig. 9.
This arrangement can be accomplished by placing the member A" of the master
blade at any point outside the path of the member M of the winding blade and it
is obvious that a degree of utility will be secured regardless of the form of the
members A and M, for the rotation of the winding blade will cause the two blades
to spread apart and thus cramp against the door and jamb and hold the alarm in its
position until the door is opened.
It is preferable, however, that the master blade and winding blade be flat, as
shown, and arranged with their width tangential to the path of the winding blade
for thereby the revolution of the winding blade produces not only a cramping of
the two blades upon the walls of the crack between the door and jamb, by reason
of their separation from each other, but also at the same time produces an additional
cramping by turning the width of the blades transverse or diagonal to the width of
the crack, thus bringing the edges of the blade into more effective contact with the
walls of the crack.
For convenience a projection a¹ is provided at the rim of the base and hinge the
member A of the master blade thereto.
It will be readily seen that the base A' and the securing member A" of the
master blade, are practically a unit to which the alarm mechanism is secured and
that the member A" may simply be an integral continuation of the base A.' or it
may be rigidly secured thereto instead of being hinged as shown, also the winding
blade M may be integral with or rigidly secured to the winding arm M'.
The blades may be made of any width desired, but it is considered preferable to
make the member A" of the master blade approximately about one-half inch wide,
and the member M of the winding blade somewhat narrower, but that is simply a
matter of construction, and the invention is not limited to any particular width or
thickness of blades.
The blades may also be arranged to hold the base of the alarm at other angles

page_text: than a right angle to the blades, and my correspondent does not limit himself to
any particular angle.
The operation is as follows:
The main spring being wound by rotating the member M of the winding blade
such member is then held in the position shown in Fig. 9, and both the member M
of the winding blade and the member A" of the master blade are inserted in the
crack or crevice. The spring Q operates to cause the winding blade M to rotate.
about the arbor E, but any movement of rotation causes the members A" and M to
stand at an angle to each other, and the greater the movement the more acute will
be the angle between the breadths of the two blades, thus enabling the blades to
clutch in any ordinary crack or crevice.
When the door or window is opened, the blades are released from the crack or
crevice, and the main spring Q then actuates the alarm mechanism, and revolves
the winding blade.
As hereinbefore described, the winding blade does not touch the master blade in
revolving. In case one revolution is deemed sufficient, the master blade may be
placed in such position that it will act as a stop to the winding blade, and prevent
more than one revolution. Other mechanism may be attached to control the
number of revolutions of the winding blade, and my correspondent does not limit
himself to any particular means therefor.
It is obvious that the base A' is simply an enlarged portion of the master
blade A" and may be made only of sufficient width to sustain the alarm mechanism,
but it is preferred to use the form shown, as thereby the mechanism is protected.
Also the winding post may be located in the centre and may be arranged to serve
also as bell post. These changes, however, are such as may be made by a skilful
mechanic without invention.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent and in what manner the
same is to be performed, I declare that what I claim is :-
1. In a portable burglar alarm, the combination of the master blade; the alarm
operating mechanism; the driving arbor journaled to the master blade and
operatively connected with the alarm operating mechanism; the main spring
operatively connecting the arbor with the master blade; and the winding blade
secured to the arbor, substantially as described.
2. In a portable burglar alarm, the combination of the master blade provided
with the serrations; alarm operating mechanism; the driving arbor journaled to
the master blade and operatively connected with the alarm operating mechanism;
the main spring secured to the sleeve; the sleeve provided with the serrations; and
means for holding the sleeve in operative contact with the serrated portion of the
master blade, and for throwing the sleeve out of such contact, substantially as
described.
3. The combination of the master blade; the main spring; the arbor provided
with the rigid main spring holding arm, the winding blade journaled upon the arbor
and means for operatively connecting and disconnecting the main spring holding
arm and the winding blade, substantially as and for the purpose set forth.
4. In a burglar alarm, the combination of the master blade; the main-spring;
the arbor provided with the rigid main spring holding arm, and the flange; the
winding blade journaled upon the arbor and provided with the flaring hole and
with the lug arranged to engage the arm; and the blade spring arranged to press
the free end of the winding blade away from the main spring holding arm, sub-
stantially as described.
5. The combination of the alarm mechanism, the frame and base, the driving
arbor journaled in such frame and base, the winding blade secured to such arbor
and arranged substantially axially parallel therewith, the main-spring attached to
the frame and arbor, and the securing blade secured to the frame and arranged to

page_text: project into a plane tangent to the circle described by the revolution of the winding
blade, substantially as described.
6. The combination of the alarm mechanism, the frame and base, the driving
arbor journaled in such frame and base, the flat winding blade secured to such
arbor and arranged substantially axially parallel therewith, and with its width
tangential to its path, the main-spring attached to the frame and arbor, and
the flat securing blade secured to the frame and arranged with its width tangential
to the path of the winding blade, substantially as described.
7. The combination of the base; the bell secured thereto; the alarm operating
mechanism secured to such base and enclosed in the chamber formed by such base
and bell; the master blade attached to such base and adapted to stand at an angle
thereto, and the winding blade operatively connected with the alarm mechanism
and adapted to stand at an angle to the base, corresponding to the angle of the
master blade, substantially as described.
Dated this 13th day of July 1801
W. P. THOMPSON & BOULT,
Agents for the Applicant.