apparatus
Year: 1887

page_text: Date of Application, 27th July 1887
Complete Left, 21st Apr., 1888
Complete Accepted, 25th May, 1888
We, JOHN THOMAS GENT, of Narborough Road, and HENRY GEORGE ELLERY of
The Fosse, both of Leicester, in the county of Leicester, Electricians, do hereby
declare the nature of this invention to be as follows:-
Our invention relates to what is known as electric pendulum signalling apparatus
for domestic and other purposes.
"
The usual form of apparatus comprises an armature carrying an arm and flag
suspended upon centres or projections of steel resting on metal supports and free to
swing in front of an electro-magnet. The armature is generally also placed in a
horizontal position relative to the poles of the magnet, which poles are fixed a short
distance below the centres on which the pendulum swings, so that when an electric
current is caused to flow through the electro-magnet and then interrupted, the
armature is first attracted and then released causing the pendulum to swing or
oscillate in front of the poles.
In our improved signalling apparatus we construct the armature carrying the flag
of equal length above and below its centre: the arm and flag being a continuance of
the lower half of the armature. A single bobbin electro-magnet is placed above and
below the working centre on opposite sides. The bracket carrying the armature as
also the electro-magnets are fastened to an iron plate, the same being fixed to a board
or iron plate attached to the cover or case of the apparatus, but in such a manner that
by loosing the fixing screws the said bracket may be turned to any position necessary
to cause the armature to hang at any required distance from the magnets. Thus, if a
short and rapid oscillation of the pendulum is required, the plate is turned so that the
armature hangs at a short distance from the magnets and, if a long and continuous
oscillation is desired, the plate is turned until the magnets are removed from the
armature a sufficient distance to give the length of swing required. By this means
the pendulum may be adjusted to swing for a few seconds or several minutes-the
period being limited only by the distance at which the armature can be attracted by
the electro-magnet

page_text: The design of the adjusting plate and pendulum is such as will allow of their being
stamped or cast in one piece thus greatly reducing the cost of production.
Electric pendulums are usually fixed behind an opaque glass or plate with open or
transparent apertures, through which the pendulums may be seen when swinging, the
glass or plate being fixed to the case which is made in several pieces, usually of
polished hard wood, put together by hand; the frame carrying the glass or plate
being screwed or hinged to the case to afford access to the interior of the latter.
We construct a case of a novel kind which may be of wood or of stamped or cast
metal. If of wool it is made of moulding to give the case an ornamental appearance
and is provided with grooves or recesses for receiving the back board or plate, the
glass plate, and a slide to keep the glass in position. The glass in some cases is
secured to the slide.
The cover or case as hitherto made is an important item in the cost of electric
pendulums but by our invention the cover may be manufactured at a nominal cost
being put together in the same manner as a picture frame. At the same time the
interior of the case is easy of access-the glass or plate is kept in position without
any fixing and the external appearance is better than heretofore.
"T
1080
G. F. REDFERN,
4, South Street, Finsbury, London,
Agent for the Applicants.

page_text: for Domestic and other Purposes.
WC, JOHN THOMAS GENT, of Narborough Road, and HENRY GEORGE ELLERY, of
The Fosse, both of Leicester, in the county of Leicester, Electricians, 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:-
Our invention relates to what is known as electric pendulum signalling apparatus
for domestic and other purposes.
The usual form of apparatus comprises an armature carrying an arm and flag
suspended upon centres or projections of steel resting on metal supports and free to
swing in front of an electro magnet. The armature is generally also placed in a
horizontal position relative to the poles of the magnet, which poles are fixed a short
distance below the centres on which the pendulum swings, so that when an electric
current is caused to flow through the electro magnet and then interrupted, the
armature is first attracted and then released causing the pendulum to swing or
oscillate in front of the poles.
In our improved signalling apparatus we construct the armature carrying the flag
of equal length above and below its centre: the arm and flag being a continuation of
the lower half of the armature. A single bobbin electro-magnet is placed above and
below the working centre on opposite sides. The bracket carrying the armature as
also the electro-magnets are fastened to an iron plate, the same being fixed to a board
or iron plate attached to the cover or case of the apparatus, but in such a manner that
by loosening the fixing screws the said bracket may be turned to any position
necessary to cause the armature to hang at any required distance from the magnets.
Thus if a short and rapid oscillation of the pendulum is required the plate is turned so
that the armature hangs at a short distance from the magnets and if a long and
continuous oscillation is desired the plate is turned until the magnets are removed
from the armature a sufficient distance to give the length of swing required. By this
means the pendulum may be adjusted to swing for a few seconds or several minutes,
the period being limited only by the distance at which the armature can be attracted
by the electro-magnets.
The design of the adjusting plate and pendulum is such as will allow of their being
stamped or cast in one piece thus greatly reducing the cost of production.
Electric pendulums are usually fixed behind an opaque glass or plate with open or

page_text: Figure 5 is a vertical section thereof.
Figure 6 is a view illustrating a modification.
a is the plate or foundation of the indicator, and bis the armature which is centrally
pivoted at c on a horizontal axis (preferably upon knife edges as shown) and provided
with the arm d and flag e.
ff are electro magnets which are placed at opposite sides of the armature b and
approximate to the ends g, g thereof respectively.
The magnets f, as shown are attached to extensions h, 2 of the plate a, the said
extensions being bent at right angles to the plate as shown in figure 3.
With this arrangement a current passed through the magnets f; f¹ will cause both
ends of the armature to be attracted simultaneously, and when the current ceases to
pass the armature with its arm and flag owing to the manner in which they are hung,
will continue to swing for some considerable time.
The portions of the armature adjacent to the poles of the field-magnets are
preferably covered with pieces of thin insulating material, for instance paper, to
prevent them from sticking to the magnets.
To cause the flag to oscillate for a greater or shorter time the plate a is adapted to
be moved, for instance as indicated by dotted lines in figure 4 in which position the
normal distances between the poles of the field-magnets and the armature is greater
than when in the position shown in full lines, so that a greater initial movement takes
place in the former position than in the latter position, indicated by full lines.
i, are curved slots for permitting the easy adjustment of the plate by means of the
screw j, j.
k is a case which as shown is adapted to contain three indicators although it may be
designed to contain any other number required. This case is composed of four pieces
of moulding or the like mitred at the corners and attached to a suitable backboard
and a sliding cover m carrying a glass front n in a recess o, figure 5.
As shown in figure 6 the glass front is supported against a ledge p in the case b
and is retained in position by the sliding cover m.
,, are binding screws for connecting the different indicators to their respective
circuits.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is
1. In electric signalling apparatus, the employment of an armature pivoted centrally

page_text: on a horizontal axis, and carrying a flag or indicator at its lower end, in combination
with two electro magnets arranged to act on the two ends of the said armature on
opposite sides thereof, substantially as described.
2. In electrical signalling apparatus, the employment of a case having a sliding
cover, substantially as described.
3. The manufacture and use of the improved electrical signalling apparatus herein-
before described and illustrated in the accompanying drawing.
Dated the 21st day of April 1888.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London,
Agents for the Applicants.