Improved Clockwork-operated Mechanism for Switching Electrical Current.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improved Clockwork-operated Mechanism for Switching Electrical
Current.
I, ARTHUR STANLEY SCULL, of 17, Redcliff Street, Bristol, Sanitary and
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention consists in improved clock-work-operated mechanism for switch-
ing electrical current. The switching action is automatic and takes place at
predetermined and set times.
According to this invention a train of clockwork is geared to a toothed wheel
on the spindle of which are carried a series of pawls, discs or pins which are
arranged to rotate with the spindle. A lever acted on by a spring is pivotted to
the frame which supports the spindle which carries the pawls, discs or pins afore-
said. The said lever is connected to one of the leads or wires for conducting the
electrical current either to a motor, or for lighting or other purpose. In the
absence of any counteracting influence, the spring forces the lever against a snail
or disc which, according to its position, either raises the lever out of a cup or
chamber containing mercury, or depresses the lever into the said cup or chamber.
Electrical connection is, when the lever is depressed, completed through the
mercury with the place at which the current is arranged to be utilized. The
circuit is maintained while the pawl, disc or pin remains in contact with the lever,
and the length of the time of contact depends on the pawl, disc or pin employed:
When, in the rotation of the spindle, the pawl, disc or pin passes clear of the
lever, the latter resumes its normal position and the electrical current is broken
as the lead or wire is lifted out of the mercury.
Instead of employing one pawl, disc or pin for establishing and breaking
current, a separate pawl, disc or pin may be used for each action.
The arrangement for setting the mechanism is analogous to that employed for
alarums in clocks, but is double acting.
Dated 1: 1011
T
1000
Improved Clockwork-operated Mechanism for Switching Electrical
Current.
I, ARTHUR STANLEY SCULL, of 17, Redcliff Street, Bristol, Sanitary and
Electrical Engineer, do hereby declare the nature of this invention, and in what
[Price 8d.1

page_text: manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
-
This invention consists in improved clockwork-operated mechanism for switch-
ing electrical current on and off. Making and breaking of circuit are effected
mechanically and at predetermined and set times.
According to this invention, a train of clockwork gives motion to a toothed
wheel on the arbor of which is carried a removable snail or cam fitted with an
index finger or pointer. A balanced lever, pivotted to the frame, carries at its
outer end a copper wire fork held in an insulating block of vulcanite or other
suitable substance. Below the fork is a pair of cups containing mercury. To
each of these cups is connected a lead or electric wire. A downwardly-acting
spring bears upon the top of the lever and keeps in constant contact with each
other the cam and a pin projecting from one side or face of the lever. The snail
or cam is so shaped that the lever is tilted on its pivot pin as the snail or cam
rotates, and, in this way, the copper fork is lowered into and raised out of the
mercury in the cups. The fork dips into the mercury at a given and predeter-
mined time and remains lowered therein during a period of time which is
regulated by the snail or cam. While the fork remains dipped, the electrical
current passes uninterruptedly, but when the fork is raised out of the mercury,
the circuit is broken.
The switch is designed more especially for use in cases where the flow of current
is required to be maintained during a given proportion of 24 hours, at the
expiration of which given time the switching action breaks the circuit, which
remains broken during the balance of the 24 hours, after the expiration of which
the circuit is re-established. This action continues during such time as the
clockwork is not stopped.
In cases where, as in electrically-illuminated advertisement signs, it is desired
to stop the operating clockwork on Sunday mornings so as to obviate illumi-
nation on Sunday nights, mechanism is provided whereby, when the appointed
hour for stopping arrives, the clockwork is stopped mechanically. It remains
stopped until restarted by hand.
Referring to the accompanying drawings, Fig. 1 represents a face view of the
clockwork-operated electrical switch in which this invention consists. The view
is that which would be seen on the removal of the dial plate of the clock, by
which plate the mechanism is, in ordinary course, for the most part hidden from
view. The movement of the clockwork is technically termed a going barrel clock
movement, and is well known.
Adapted to rock on the pin a fixed to the clock frame is a lever c to one end
of which is fixed a block d of vulcanite or other suitable insulating material. The
block & carries a fork e of copper wire. An end view of the block d with fork e
is shown at Fig. 2. Below the fork eis a pair of cups or wells f containing mercury.
The cups are sunk in a block of insulating material such as slate fixed to a
plate attached to the clock case or to any other convenient place of support. In
holding brackets f' attached to the cups f are clamped the wires or leads f of
an electrical circuit. At the opposite end to the fork the lever e carries a balance
weight c¹.
Projecting forwards from the front face of the lever c is a pin c2 which, by the
spring acting on the lever c, is kept always in contact with the snail or cam h
clamped on the arbor which is supported in the frame of the clock and has
secured upon it a toothed wheel i which is driven off the barrel. This wheel i
makes a complete revolution in 24 hours.
At Fig. 3 is shown a plan of the snail or cam h. It is readily removable from
the arbor h¹, but, when in place for action, it is secured by the clamping nut h² so
as to turn with the arbor h¹.
When, in the rotation of the cam h in the direction indicated by the arrow,
Fig. 1, the part of largest diameter comes under the pin c², the lever c is tilted
on the pivot pin a so as to lower the fork e and cause it to dip into the mercury

page_text: in the cups f. The electric circuit is thus established and the current flows to
the place where it is to be utilized. It continues to flow while the part of largest
diameter of the cam h is in contact with the pin a. When the said part has
passed clear of the pin a, the lever is tilted in the reverse direction to that
required for dipping the fork into the cups f, and the fork is consequently raised
out of the cups and the electrical circuit is broken.
Obviously, the length of time during which the circuit is established depends
on the length of the part of largest diameter of the cam h. In the example
illustrated, the cam is such that the electrical circuit remains estabushed for four
hours, and, consequently, remains broken for twenty hours.
The
It is desirable, in order to prevent sparking, that the limbs of the fork e
should, after having been lowered gradually to a given point, be sharply plunged
thence into the mercury. In order to effect this, the lever c is made relatively
thinner at 3, and below the thin part is a plate j rivetted at to the lever c.
outer end of the plate j is not closely connected to the levere which has play to
bend to the extent allowed by the regulating screw k. When the lever c is tilted
to lower the fork e the lever bends, after an interval, at in the sense that there
is a temporary raising of the fork. This continues until the top of the spring k
enters the notch. The lever then returns to the plate sharply, thus dipping
the fork e suddenly into the mercury from a point to which the fork has been
gradually depressed.
To guide in setting the cam h to establish the electrical current at an appointed
time, a special dial is provided on the dial plate of the clock, as seen at Fig. 4
which represents a face view of part of the dial plate of the clock. is the hour
hand and the minute hand. m is the winding arbor of the clock. The special
dial for the cam is indicated at A.
The cam carries a pointer the finger of which coincides with the commence-
ment of the point of largest diameter of the cam h, that is to say, with the moment
at which the cam acts upon the pin 2 to lower the fork e into the mercury. The
circle of the cam dial is graduated into hours. Zero corresponds with the pin
of the lever c. The index finger is shown set in Fig. 4, which corresponds to
Fig. 1, indicating that the fork e will be lowered in seven hours, and the electrical
circuit will then be established. The period of time to elapse before the dipping
of the fork, may be varied by setting the cam h accordingly. When the pin
reaches the end of the part of largest diameter of the cam h, the fork e is sharply
raised out of the mercury in the cups and the electrical circuit is broken. The
length of the part of largest diameter of the cam is governed by the period of
time during which the circuit is to be kept established, but, instead of having a
separate cam for each period, the cam may have a fixed length and be extended
by separate pawls, pins, or discs, removably attached to it.
In cases where it is desired that the clock shall stop at an appointed time, an
arrangement of mechanism is employed therefor.
The arrangement adopted in connection with the switch above described and
illustrated in the accompanying drawings, consists of a lever n pivotted at n¹ and
held up by a spring n³ fixed to the clock frame and pressing against the under
edge of the lever n. Keyed or otherwise fixed on an arbor o supported in the
olates 6 of the frame is a toothed wheel o' driven from a pinion centred on the
arbor m of the barrel. The wheel o¹ makes a complete revolution in 6 days of
24 hours each. On the arbor o is centred a pawl p of which a plan is shown at
Fig. 5. The pawl 2 is readily removable from the arbor o, but when in place
or action, it is secured by the clamping nut p¹ so as to turn with the arbor o in
he direction indicated by the arrow, Fig. 1. The pawl is set so as to come into
ontact with the lever n at a given time. After coming into contact it forces the
ever n down and back, and when the lever arrives at the stop pin g, the motion
f the clock is stopped. Release is effected by pulling down the lever n by means
f the pin n³ until the point nt is clear of the pawl p. The pawl p then resumes

page_text: rotation and the point n of the lever in rebounding passes up at the back of
the pawl.
To guide in setting the pawl 2 to stop the movement of the clock at an
appointed time, a special dial is provided on the dial plate of the clock, as seen
at Fig. 4 in which it is indicated by the letter B. The pawl carries a pointer 22
the finger of which coincides with the pointer-or nose of the pawl p. The circle
of the dial B is divided into six divisions representing six periods of one day each.
In the example illustrated, the stopping is set to take place when the pointer
finger arrives at an hour on Sunday corresponding to the hour on which it was
started. Starting is, as aforesaid, effected by pulling down the pin ³ in the
slot n³.
The finger of the pointer must be so placed as to correspond with the name of
the day on which the mechanism is started.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
-
1. Clockwork-operated mechanism for actuating electrical switches; consisting
of a lever such as e adapted to rock on a fixed pin and acted upon by a spring
such as g
and an adjustable and variable snail or cam such as h, or the equivalent
thereof; the arrangement being such that at a given time and for a predeter-
mined, set and limited period of time the said lever is so tilted as to cause a copper
fork such as e carried at one end of the lever to descend and be partially immersed
in mercury contained in cups or wells such as f to which the leads or wires of the
circuit are connected, and at the expiration of the said predetermined, set and
limited period of time the lever is again tilted so as to raise the fork out of the
mercury, substantially as herein before described.
2. In clockwork-operated mechanism for switching electrical currents, such as
is set forth in the preceding claim, the arrangement for plunging the circuit-
making and breaking fork e into the mercury suddenly after having been de-
pressed gradually to a given point; the said arrangement consisting of the
spring, plate j, notch in the lever c; the said lever being made flexible as
at, the parts being constructed, arranged and operating, substantially as here-
inabove described with reference to the accompanying drawings.
3. In connection with clockwork-operated electrical switches, mechanism for
stopping movement of the clockwork at a given and previously set time; con-
sisting of the toothed wheel o', adjustable pawl p, lever n, stop-pin q and spring n²,
the said parts being constructed, arranged and operating substantially as herein-
before described with reference to the accompanying drawings.
Dated this 19th day of October 1898.