An Improvement in the Contact Makers of Electrical Alarms for Doors and Windows.
Year: 1888

page_text: Date of Application, 7th Nov., 1888
Complete Specification Left 7th Aug. 1889-Accented. 2nd Nov.. 1889
PROVISIONAL SPECIFICATION.
An Improvement in the Contact Makers of Electrical Alarms for
Doors and Windows.
1 JOSEPHI EMILE LANSARD of 216 Goswell Road in the County of Middlesex,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to the contact makers of burglar and other alarms, whereby
the opening of a door or window is denoted by the closing of an electrical circuit
and the sounding of an alarm.
Heretofore it has been usual to provide a switch whereby when it is desired to
purposely leave a door or window open, the circuit is permanently broken and such
switch has generally controlled the action of the whole installation so that when one
window is left open the alarm has been rendered inoperative for all the others.
The object of my invention is to provide a contact breaker at each contact maker
so that the alarm may be rendered inoperative for any one door or window without
affecting the others and which by the act of closing the window permits of the contact
maker coming automatically into action.
To this end my contact breaker consists of an insulating block carried by a thumb
bolt movable freely in a vertical slot and which when raised will come between and
separate the spring of the contact maker from the plate with which it is intended to
make contact and will be held by the said spring in that position so long as the
window or door remains open but which when the window or door is closed will be
released by the pushing back of the spring by door or window and will fall out of
operative position so that when the door or window is again opened the alarm will
operate.
ليد
Low 1000
J. E. LANSARD.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.
COMPLETE SPECIFICATION.
An Improvement in the Contact Makers of Electrical Alarms for
Doors and Windows.
I, JOSEPH EMILE LANSARD of 216 Goswell Road in the county of Middlesex,
Engineer, do hereby declare tho 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 :-
Reference being also had to the accompanying drawing in which Figures
and 2
are respectively front and back views of my improved contact maker, Figure 3 a
side elevational view, and Figure 4 illustrating an independent means for operating
same.
My invention relates to the contact makers of burglar and other alarms whereby
the opening of a door, window or the like is indicated by the sounding of an alarm
caused by the closing of an electrical circuit.
Hitherto it has been customary to employ a switch for the purpose of breaking the
electrical circuit when it is desired to leave a door, window or the like open, which
switch (when one only is used) has controlled the entire installation. This, it will bo
readily seen, is an evident disadvantage, inasmuch as, when one window, for instance,
is left open, and the electrical circuit broken, the alarm is rendered inoperative for all
other doors, windows and the like to which contact makers may be adapted. Aly
invention is therefore devised with the object of overcoming this disadvantage by
providing each contact maker with an independent contact breaker, so that, upon
opening any door, window or the like, the electrical circuit, by means of an insulated

page_text: stud, button, bolt or equivalent, may be broken only at that particular part, without
in any way affecting the other contact makers introduced into such electrical
circuit.
In carrying out my invention I provide a plate of brass or other suitable metal A
bored or otherwise perforated with countersunk holes a to allow of the attachment of
said plate to the side of the frame of a door, window or the like, so as to present a
flush surface. At the back of tho plate aforesaid, is mounted, upon a block or plate b
of suitable insulating material a strong spring B which presses firmly against the
back of the plates; and, in order to ensure perfect electrical contact therewith, I tip
the spring, at any convenient part thereof, with a plate or point e of a suitable
nonoxidisable metal, preferably platinum. Upon the free end of the flat spring
aforesaid, I secure by suitable means a block C of suitable insulating material, which
projecting beyond the front surface of the plate through a slot formed therein for
the purpose, allows the contact being broken when the door window or the like is
closed by the pressure of the frame thereof against the block of insulating material
above described upon the free end of the flat spring as shown in dotted lines
Figure 3.
In a convenient part of the plate aforesaid, but preferably between the fixed and
free ends of the flat spring, I cut or otherwise form a longitudinal slot d recessed or
otherwise as may be desired, in which is inserted and free to move a headed pin D
provided on its interior end with a button, block or bolt of insulating material d
which, being pressed upwards, passes between the plate and the spring thus breaking
contact. In this position the button d' would be retained by the tension of said spring
until, by the closing of the door, window or the like, the block of insulating material (
at the free end of the spring being pressed further inwards, the insulating button d¹
would be released, and fall back by its own gravity to its normal position. If how-
ever from any cause, the moveable button should stick or otherwise become inoperative,
I may employ a light spiral spring or equivalent to bring back the insulating button,
block, or bolt to its normal position.
Instead of the insulating button, block or bolt aforesaid moving longitudinally
in a slot may employ a cam or equivalent device revolving upon its axis and
actuated by a suitable thumb nut, by which means the electrical circuit may be broken
in an equally effective manner; the cam, when released, being returned to its normal
position by a spiral spring, spider spring or by equivalent means.
The arrangement shown by side and front elevation Figure 4 for independently
actuating the aforesaid contact maker from the outside of the room or otherwise,
comprises a back plate E, secured by screws, and formed with a vertical slot in which
the screwed end of a projecting catch or arin G is caused to slide. Within a second
plate sliding vertically by the guide e the catch or arm G is secured by the milled
headed thumb nut f. Upon lifting the sliding plate F by the thumb nutfit will be
seen that the catch or arm G, will, when so raised, come in contact with the insulating
button Figure 3 thus forcing same between the plate A and spring B, causing the
latter with its contact point or plate e to assume the position shown in dotted lines
thus breaking circuit until the catch or arm G is lowered.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed I declare that what I
claim is.
In electrical alarms for doors, windows and like purposes, the combination with
and adaptation thereto of a contact breaker whereby the electrical circuit may be
broken at each open window, door and the like without affecting other contact makers
in the electrical circuit, said contact breaker being automatically released upon closing
such door, window and the like substantially as described.
T11
JAMES STEVENSON,
Gray's Inn Chambers, 20, High Holborn, London, W.C., Agent for Applicant.