Improvements in Alarm-knobs.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in Alarm-knobs.
I, EDWARD CURTISS GARLICK, of 93, Cunard Street, Cleveland, in the
County of Cuyahoga and State of Ohio, United States of America, Manufacturer,
do hereby declare the nature of my invention for IMPROVEMENTS IN ALARM-
KNOBS, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
My improvement relates to alarm-knobs for doors in which a portion of the knob
forms a gong or bell and the turning of the knob causes the alarm to strike; and
the invention consists in the novel arrangement of parts by which the striking
mechanism is attached to the knob-spindle independent of the knob itself, greater
certainty of action is secured, the size of the knob is reduced, and the device is
adapted to be attached to any door-lock or knob-latch in common use.
Figure 1 of the drawings shows the device attached to a door-lock as in use, the
striking parts being shown in elevation and the knob and rose in vertical central
section.
Fig. 2 is a detached view of the spindle-bar and striking mechanism, showing the
lower side thereof.
Fig. 3 is an end elevation of the same with the gong part of the knob attached.
Fig. 4 is a transverse sectional view on the line of the knob-shank.
Fig. 5 is a plan view of the knob-rose, and
Fig. 6 a section thereof on the line yy.
Fig. 7 shows in perspective a detached view of all the striking parts except the
hammer, and
Fig. 8 is a like detached view of the striker-pin and stop-pin.
A represents the spindle-bar, which is of the usual standard size and con-
struction.
B and B are the two parts of the shell which form the hollow knob, and either
of which may act as the gong or bell. The outer shell B is firmly secured to the
end of the spindle-bar, as hereinafter described, and slightly overlaps the inner
shell B¹, which is secured to or integral with the shank b', a slight space being left
between the shells B B at their periphery to give resonance to the part struck and
allow its vibration. To the spindle-bar A is secured, within the hollow knob, a
base-plate a, and to this base-plate is pivoted a striking-arm c, having a stop c¹,
adapted to rest against the spindle A, against which it is normally held by a
spring. To the free extremity of the striking-arm c is pivotally attached. the
freely-moving hammer D, which normally falls back by gravity out of contact
with the shell of the knob. A pawl or dog E is pivoted to the base-plate in such
position that its free end bears against a shoulder on the striking-arm when the
latter is in its normal position, and the pawl is drawn forward by a spring g, bearing
on an arme of the pawl. The bearing of the pawl E on its pivot is an elongated

page_text: slot and allows the pawl to be forced back on its pivot far enough to clear the
shoulder when moved by the stop-pin, as bereinafter described. The rose in
which the knob bears differs from the usual form only in having a V-shaped groove k
cut across the bearing-surface. A pin L, designated as the 'striker-pin,' is inserted
loosely through the knob-shank 1, parallel with and close to the spindle A. One
end of this pin is beveled on each side to fit the groove k in the rose, and the other
end is adapted to bear against the pawl E and force it forward when the knob is
turned. To enable the knob to be turned without striking the alarm, when so
desired, a stop-pin o is inserted through the knob-shank ', parallel with the striker-
pin, in such position that when pushed in by means of a lug or handle its inner
end will engage the rounded or beveled end of the pawl E and force the pawl to
slide on its pivot, so as to be disengaged from the shoulder c² of the striking-arm.
In this position the pawl, when pushed forward by the striker-pin L on the turning
of the knob, passes freely by the striking-arm, sliding on the pin o, and does not
actuate the alarm. A cross-groove m is cut from the slot in which the lug p travels,
and by turning the lug into this cross-groove, the pin o is locked in position to
prevent the alarm from sounding. On drawing back the pin o from engage-
ment with the pawl the spring g at once restores the pawl to its operative position,
in engagement with the shoulder c of the striking-arm.
"
The operation of the device is as follows: The stop-pin being released and drawn
back, the parts are in operative position. If either knob of the door is turned in
either direction, the pin L will ride up the inclined face of the groove k in the rose,
and being thus pushed into the knob will force forward the pawl E, thereby turning
the striking-arm on its pivot and compressing the spring until the striking-arm
has turned far enough to let the pawl slip off the shoulder c², when the spring will
throw forward the striking-arm, bringing its stop e' against the spindle A, and
causing the hammer D to fly up and strike a quick sharp blow upon the shell
of the knob, falling back out of contact by its own weight. The proportions of
the parts are such that the striking-arm will be released before the knob has turned
far enough to wholly withdraw the latch-bolt. Hence the alarm must strike before
the door can be opened, unless the stop-pin has been set and locked, as above
described, which can only be done from the inner side of the door, to which the
alarm-knob is attached. As soon as the alarm strikes, the spring g draws back the
pawl E into re-engagement with the shoulder c² ready for another stroke.
In order to prevent the shells B B' from coming in contact at their edges, which
would destroy the vibration of the gong when struck, it is essential to secure the
correct centering of the outer shell B with the spindle, unless a wide and unsightly
opening is left between the two shells. At the same time, since the shell B is the
part grasped by the hand it must be very firmly and solidly secured to the spindle
to prevent its being bent or displaced or loosened. To accomplish these ends I turn
the shoulder h on the end of the spindle, central therewith, and form a boss or
short central stem i on the inside of the shell B, which is centred and drilled to
receive the shoulder h. A cross-groove is milled out across the inner end of the
stem i to exactly fit the square body of the spindle A. The end of the shoulder h
is tapped to receive a screw s, which in mounting the shell B on the spindle is
turned in from the outside and binds the shell firmly on the spindle. The screws is
preferably made of the same material as the shell B, and when turned firmly into
place is cut or ground off even with the outer surface of the knob, and when the
knob is finished in the usual manner the screw is wholly undistinguishable and
cannot be removed by any ordinary means, but locks the spindle in place with the
utmost rigidity.
By dispensing with cranks or slides attached to the knob and acting crosswise
thereof am enabled to use a smaller knob than has before been practicable, and
by dispensing with rigid or spring hammers and employing the loose gravitating
hammer I avoid the deadening of the blow by the wear or set of the hammer-arm
allowing it to come too close to or in contact with the bell.

page_text: 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 :-
1. An alarm-knob consisting of a hollow shell adapted to act as a gong or bell
and having the striking mechanism secured to the spindle of the knob within the
shell and operated by a sliding pin actuated by an inclined face on the rose-plate
substantially as described.
2. An alarm-knob consisting of a hollow shell adapted to act as a gong or bell
and having within the shell the striking mechanism secured to the spindle and in
its shank the operating-pin engaging an inclined face on the rose-plate, and a
stop-pin adapted to set and lock the striking-mechanism out of engagement,
substantially as described.
3. In an alarm-knob, the combination of a hollow shell adapted to act as a bell,
the striking mechanism attached to the spindle within the shell and having the
loosely-pivoted striking-hammer, the sliding pin with beveled end inserted in the
knob-shank, and the rose-plate with inclined face for actuating the pin, substantially
as described.
4. The combination, with the hollow knob adapted to act as a bell, of the alarm
mechanism consisting of a base-plate secured to the spindle, the striking-arm
pivoted to the base-plate and having the striking-hammer loosely pivoted to its
free end, the pawl pivoted to the base-plate and engaging the striking-arm, the
sliding pin adapted to bear upon and push forward the pawl, the inclined face on
the rose-plate to actuate the pin, and a stop-pin adapted to force the pawl out of
engagement with the striking-arm and to be locked in that position, substantially as
described.
5. In an alarm-knob, the combination, with the hollow knob adapted to act as a
bell and having attached to its spindle the base-plate a, with striking-arm and pawl
pivoted thereto, of the gravitating hammer pivoted to the striking-arm, substan-
tially as described.
6. In an alarm-knob, the combination of the knob-shell having a central internal
stem with central bearing adapted to receive the shoulder of the spindle, and
transverse groove adapted to fit the squared faces of the spindle, with the spindle
having a shoulder fitting the central bearing of the stem and a squared portion
fitting the transverse groove thereof to prevent the turning of the knob on the
spindle, substantially as described.
Dated this 10th day of February 1891
.
F. W. BARKER,
Applicant's Agent.