Improvements in the Electrical Illumination of Clock Dials and Apparatus in Connection therewith.
Year: 1888

page_text: Improvements in the Electrical Illumination of Clock Dials and
Apparatus in Connection therewith.
I, ERNEST GEORGE CRAVEN of 22 Great George Street Westminster, London, S.W.
do hereby declare the nature of this invention to be as follows:-
My present Invention has for its object the momentary illumination of the dial of.a
clock at stated intervals of time, said illumination being effected automatically by the
mechanism of the clock.
In carrying out my Invention 1 provide a wheel or cam upon the spindle of either
of the wheels of the clock train that may be suitable. Said wheel or cam is placed in
juxtaposition to an electrical contact spring or springs in such a manner that the
electrical contact is established and the circuit closed each time that a projecting part
of the wheel or cam aforesaid presses upon said spring or springs during its
revolution.
I may suspend from a suitable bracket an electrical incandescence lamp, with a
hood and reflector so that the intermittent light is thrown upon the dial, or I may
make the latter of any suitable semi-transparent substance and place the lamp behind
it. I prefer to obtain the current from a constant primary battery, and connect the
electrodes of the same with the contact spring before referred to.
In this manner I am enabled to illuminate the dial, and render the figures thereon
visible, at stated intervals of time similar to the "flash" light employed for light houses,
the duration of the flash being arranged by the adjustment of the breadth of the
revolving contact, and the interval of time between said flashes by the number of such
contacts, and also the relative speed of the spindle from which the contact wheel´or cam
receives motion, I prefer however to arrange the apparatus so that a flash of about five
seconds duration occurs every five or ten minutes throughout the night, a suitable
switch allowing of the current being switched off during the day.
FREDK. WALKER & HYDE,
4, Little Moorfields, E.C.,
Agents for Applicant.

page_text: I, ERNEST GEORGE CRAVEN of 22 Great George Street, Westminster, London, S.W.
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:
My present. Invention. has for its object the momentary illumination of the dial of a
clock, at stated intervals of time, said illumination being effected automatically by,
means of the mechanism of the clock, in connection with a suitable source of electrical
energy.
In order that my Invention may be clearly understood, I have appended the
accompanying two sheets of drawings in which Figure 1, Sheet 1, represents a front
view of a clock, with the glass dome, or face cover opened, exposing the lamp fitted
thereto according to my Invention. Figure 2 upon the same sheet is a corresponding.
view of the back of said clock, with door removed shewing the electrical connections..
Figure 3 Sheet 2. is front and side elevational views of a wheel, fitted with an
electrical time contact. Figure 4 shews front and side views of the time switch,
hereinafter to be fully described. Figure 5 is an alternative arrangement for a time:
contact, and Figure 6 is a diagram of the electrical circuit. Similar letters of
reference indicate corresponding parts throughout the several views.
In carrying out my Invention I provide an incandescence or glow lamp A, Figure 1,
Sheet 1; preferably fitted within a suitable recess formed within the casing of the
clock, above the dial. I may, however, in certain cases form the latter of transparent,
or semi-transparent material, and place the lamp behind it, the object being to perfectly
illuminate said dial, and render the figures marked thereon visible, in both cases. In
order to concentrate the rays of light, I may employ a suitable reflector and hood, or
I may use two or more lamps in order to intensity and increase the light.
I connect one terminal of said lamp or lamps to the metallic frame of the mechanism
of the clock, in such a manner that the latter serves the purpose of a conductor, I may:
however, in certain cases prefer to carry an independent wire or plate conductor in.
lieu of the aforesaid "body" contact. To one of the wheels of the clock train,:
preferably the third, I attach a slender contact spring c as shown by Figure 3, Sheet 2.
A point d, Figure 3 sheet 2, tipped with platinum or other non oxidisable metal or
material, is attached to the frame, or "plate e of the clock, a piece of any suitable
insulating materialf being interposed so as to insulate the point d from the body of
the clock: During the notion of the clock, the wheel D revolves upon its spindle or
arbor E at a certain rate per hour, according to the design of the clock, and once in

page_text: each revolution brings the contact spring c into electrical connection with the insulated
point d and thereby establishes an electrical circuit of short duration. Said insulated
point d is connected with one electrode of a suitable battery or generator, a terminal b.
being provided for this purpose, or an equivalent device. The opposite pole of the
battery or generator: is coupled to the terminal or equivalent 61. and a wire or;
conductor u is led therefrom to an insulated brush or spring contact'h, which bears
upon the adjustable disc or drum C, Figure 2, sheet 1, and shewn more particularly,
and detached from the clock, by Figure 4 sheet 2. Said disc or drum C is fitted upon
an extension of the arbor or spindle of a wheel, which is introduced into the train of
gearing in such a manner as to revolve once in each twenty-four hours. A segment g
of some suitable insulating material is fitted to the disc or drum C in such a manner
as to shroud half the periphery of said disc or drum. When the brush or contact spring h
bears upon the metallic portion of the disc or drum C, the current is conducted from
the battery through the lamp or lamps each time that the intermittent contact shewn
by Figure 3, closes the circuit, but, when; during the diurnal revolution of the disc or
drum, C, the insulating segment g is brought into contact with the brush or spring h,
the intermittent contact before mentioned: is inoperative, and an electrical circuit
cannot be established. In this manner the lamp or lamps may be automatically
switched out of circuit during the day time, and may be caused to act, and illuminate the
dial at any predetermined hour by setting the index finger v, fixed to the back of the
drum C to such hour as may be required, the drum C being free to move upon
the spindle or arbor; when the thumb or fly nut i is slackened upon the screwed
extension k. A suitable range of figures may be marked upon the plate or frame, as
shewn by Figure 2, for conveniently setting the automatic time switch C above
described.
In carrying out the device or contrivance according to my Invention, I do not
confine myself to an intermittent contact formed by a spring and point as herein before
described, but may make use of a glass or metallic mercury tube 1, Figure 5 the two
ends whereof are separately attached and electrically connected to the wheel q and a
metal disc p which is insulated from, but carried by, the wheel 9, which moves upon
and with the arbor or spindle r, and fulfils the usual function in the clock train. Two
points, preferably of non-oxidisable metal, are placed close together within the mercury
tube, and are respectively connected to the disc p, which is insulated from the
wheel q by the insulating disc o; and to said wheel q by means of the metal arms m
and n, so that when, during the revolution of the whole, the mercury becomes
displaced by the action of gravity, electrical contact is momentarily established
between the points before referred to. The electrical circuit is preferably arranged as
shewn by the diagram, Figure 6, sheet 2, where s represents the intermittent contact,
A the lamp, C the automatic switch, and F a battery, accumulator or other source of
electrical energy, t and u being the conductors leading thereto.
I may, however, without departing from the essential features of my Invention
connect the whole apparatus electrically in any suitable manner. I may also apply
the device or contrivance according to my Invention, upon a larger scale, to turret
clocks, or large church clocks, using an incandescence lamp of great illuminating
power, or an arc lamp, or lamps, in connection with the intermittent contact above
described, with or without the automatic switch.
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 1
claim is ;
First. A device for illuminating the dial of a clock by means of an electrical lamp
or lamps, intermittently by means of a time contact substantially as herein described
and shewn in the accompanying drawings.
Second. In an illuminating device as referred to in the preceding claim, a spring
and point contact with or without an automatic switch, as and for the purposes herein
set forth.

page_text: Third. In an illuminating device as above, the employment of an automatic switch
with arrangement for adjustment, substantially as and for the purposes herein described
and shewn.
Fourth. In an illuminating device for clock dials, the employment of a mercury
tube for establishing an intermittent and momentary electrical circuit, substantially as
herein described.