Improvements in the Construction of Bells or Alarm Signals.
Year: 1891

page_text: te of Application, 7th Apr., 1891-Accepted, 18th July, 1891
COMPLETE SPECIFICATION.
Improvements in the Construction of Bells or Alarm Signals.
I, THOMAS RHODES PIXTON, Dentist, residing at Lancaster, in the County
of Lancaster and State of Pennsylvania, United States of America, do hereby
declare the nature of my 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 improvements in bells, whether used as door bells, call
bells, or with burglar or other alarms; and the object of the invention is to com-
municate motion from the actuating mechanism to the hammer of a bell with less
jar on said mechanism and less wear on the parts connecting said mechanism and
the hammer than has heretofore been done.
The invention consists in imparting a vibrating movement to a lever or stemn
carrying a bell-hammer by means of a cam or eccentric.
I carry my invention into effect by securing or forming a cam on a rotary shaft
actuated by any suitable mechanism, preferring, however, for ordinary purposes, the
clock movement hereinafter described. With the cam is employed a lever, rigidly
fastened between it's ends to a rock shaft, which serves as a fulcrun about which
said ends of the lever move. A hammer is mounted on one end of the lever, and in
the other end there is formed an elongated loop or slot, which surrounds or embraces
the periphery of the cam. By the revolution of the rotary shaft a vibratory motion
is imparted to the hammer. This use of the cam avoids much of the friction
connected with the 'employment, for the same purpose, of escape-movements similar
to those used in clock works, and greatly reduces the wear of the contacting surfaces
and the jarring of the whole operating mechanism.
The accompanying drawing illustrates the principle of my invention and also the
manner of carrying the same into effect. It also shows different modes in which
the power of the mechanism for actuating the rotary-shaft may be controlled.
In the drawing:
Fig. 1 is a face view of the case containing the operating mechanism;
Fig. 2 is a view of the case in the same position, but with the front plate removed
to show the operating mechanism contained between the plates;
Fig. 3 is a side view of the case and the mechanism contained therein, taken on
the side indicated by the arrow in Fig. 1;
.
Fig. 4 is a top view of the same;
Fig. 5 is a side view of the lever (shown in front view in Fig. 1), for controlling
the movement of the actuating mechanism, the lever and the parts connected there-
with being detached from the other portions of the device;
Fig. 6 is a bottom plan view of a push-button, taken on the line -, Fig. 1, the
push-button and the parts connected therewith being detached from the other
portions of the device;
Fig. 7 is a perspective view of the operating cam and levers, also detached;
Figures 4, 5, 6 and 7 are enlarged to more fully show the details of construction.
In use, the mechanism herein described may be placed in any desirable position,
but for the purposes of this Specification the words "front," "side," 'top,'
bottom," and similar expressions refer to the relative positions of the various parts
as located in the accompanying drawing.
65
Referring to the details of the drawing, A indicates the front plate of the case
and B the back plate. These plates serve as a support for and protection to the
parts held between them. The upper portions of the plates have in face view some-
what the general outlines of a segment of a circle, with the lower portions reduced
or contracted, as shown.

page_text: CC represent the upper posts connecting the plates A and B of the case, and
C' the lower post, the plates A and B being held at such distance apart as to allow
space between them for the operating mechanism.
Findicates an arbor journaled in the upper part of the reduced portions of the
plates A and B and has loosely mounted thereon the gear-wheel f. A pawl m is
pivoted to one of the spokes of the gear-wheel and is held in engagement with the
ratchet M, keyed to the shaft F by a spring m rigidly secured to the wheel. The
gear wheel meshes with a lantern wheel g mounted on an arbor G, located to the
right of and above the arbor F. On the arbor G is also mounted a gear wheel y',
which meshes with a lantern wheel h, carried on an arbor H, journaled above the
arbor F. On the arbor H there is again mounted a gear wheel that meshes with
a lantern wheel i, mounted on the arbor I, which located to the left of and above the
arbor and carries the cam i¹.
The cam is engaged in or surrounded by an elongated loop j¹ formed on the
inner end of a lever J, which is rigidly secured between its ends to a rock shaft K,
placed to the left of the shaft I. The other end of the lever has a hammer or
clapper & fastened to it, which, in vibrating, is brought into contact with the gong L.
The gong shown is placed in the position it occupies in the drawing, simply for the
purpose of illustration, as it may be located in any desirable position, or it may be
made to entirely cover the case containing the operating mechanism.
S indicates a flat spring coiled about the arbor F and having one end fastened
thereto. The other and outer end passes downward and is secured to the post C¹,
as shown in Figures 2 and 3. This spring is wound up by turning the arbor F, an
ordinary clock key being applied to the winding arbor w forming an extension of
the arbor F. During the winding of the spring about the arbor F the other parts
of the gearing remain stationary by reason of the pawl and ratchet connection of the
wheel with the arbor F.
When the spring is wound up it acts to revolve the cam shaft 1 through the
action of the gearing just described, as a consequence of which revolution the cam i
imparts a vibrating motion to the lever J and the hammer carried by it. This
mode of imparting motion to the lever I has a number of advantages over the
escape-wheel and pallet generally used for the purpose, iz.: The movement of the
parts is smooth and continuous, avoiding the jarring and shocks produced on
the whole mechanism by the use of the escape-wheel and pallet; there is less friction
between the cam and the sides of the loop than between the escape-wheel and the
pallets and there is less wear of the contacting parts of the cam and loop than of
those of the arms of the pallet and the teeth of the escape-wheel, and consequently,
parts are less liable to get out of order.
the
N indicates a stop pivoted on the stud n, projecting from the inner face of the
plate B. This stop is located above all the arbors and between the arbors G and H.
The free end of the stop extends toward and, in its normal position, intercepts the
path of a pin, projecting from the shaft I, and is held in that position by the end
of a spring n', coiled about the stud n. The lower edge of the stop is beveled on
the side adjacent to the plate B, as shown at p, Fig. 6. An angle-plate n² is secured
to the plate B above the stop N and between the stud n and arbor 1. This angle-plate
extends inward over the stop and is then bent to form a flange which passes down
inside of the stop, as shown in Fig. 4. Beneath the stop there is located a push-
button O, having its bearings in the plate B and the dependant portion of the
plate n. On the button there is formed a boss P, the inner end of which is conical
in shape. Pressure upon the button engages the boss with the bevel p and forces
the stop upward out of the path of the pin, thus permitting the revolution of the
arbor I by the spring S. Upon the removal of the pressure on the button the stop
is again thrown into the path of the pin 2, and the revolution of the cam is stopped.
If preferable, the push-button may be omitted and a pull-cord Q, attached to the
stop N, may be used as shown in Figures 2, 4 and 6, to disengage said stop from the
pin.
In Figures 1 and 5 is shown another form of stop.
.
This consists of a lever R,

page_text: pivotally mounted on a post r, located on the outer face of the plate A. One end
of this lever is provided with a finger rest, and the other end is bent inward and
forms a prong t, which passes through an opening T in the plate A, and, when in its
normal position, engages a pin t, projecting from the lantern wheel i. The prong
is held in engagement with the pin by a spring, riveted to the face of the
plate A and bearing against the outer end of the lever R to force that end outward.
The effect of the engagement or disengagement of the lever R with the pin t¹ is the
same as that resulting from the engagement or disengagement of the stop N with
the pin
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:
The mode herein described of imparting a vibratory movement to a bell hammer
by means of a cam or eccentric, wherein a pivoted lever or stem carrying a hammer
is engaged with the periphery of a revolving cam or eccentric.
Date GIS
S. S. BROMHEAD,
97, Newgate Street, London, E.C., Patent Agent.
S. S. BROMHEAD,
97, Newgate Street, London, E.C., Patent Agent.