provements in Electric Signal Lamps and Appliances connected therewith,
Year: 1889

page_text: * Date of Application, 4th June, 1889
Complete Specification Left; 4th Mar., 1890-Accepted, 10th May, 1890
PROVISIONAL
CITIGATION
Improvements in Electric Signal Lamps and Appliances connected
therewith,
We, FREDERICK LAWRENCE RAWSON of 60 Hammersmith Road, in the County of
Middlesex, Electrical Engineer and WILLIAM STEPNEY RAWSON of 68 Cornwall
Gardens London in the County of Middlesex, Electrician, do hereby declare the
nature of this invention to be as follows:-
The object of the invention is to produce an improved signal lamp for marine and
other purposes and is especially applicable to lamps in which an electric lamp is
used as the source of light and where the signals are conveyed by means of electric
impulses.
1
The lamp is mounted in a lantern which can be suspended at the mast head or yard
arm and which is provided with a circular dioptric lens or other known method of
producing horizontál beams of light. In one form of apparatus surrounding the
lamp are a number of blinds or shutters which may revolve on vertical pins and be
actuated by a wheel or similar mechanism which by its motion engages with each
shutter and causes them to turn through about 90 degrees.
The motion of this wheel can be produced by the movement of an armature due to
the magnetic attraction of an electro-magnet.
The passage of a current through the electro magnet causes the armature to move
and carry with it the wheel against the force of a coiled spring. By this action the
shutters may be opened or shut.
On the cessation of the current the spring carries the wheel back to its original
position and the shutters are shut or opened by the wheel. By opening and closing
the shutters flashes of light are seen round in all directions and so can be used for
signalling purposes.
In order to avoid the lamp being always run at its full incandescence when the
light is cut off by the closed shutters, whose place may be taken by the halves of a
cylinder or a telescopic arrangement, we put the electro-magnet in series with the
lamp and we arrange the mechanism of the shutters so that when no current is
passing the spring opens the shutters but on the passage of the current the attraction
of the armature causes the shutters to close and at the same time the lamp is rendered
duller by the resistance in circuit with it. If desired a special resistance can be
put in by the action of the mechanism either separately or together with the electro
magnet.
By this arrangement the heating inside the lantern which is a closed form is
greatly reduced and the life of the lamp increased. A simple key for cutting the
electro-magnet out of circuit is all that is necessary. With this key I may combine
a recording instrument of the Morse or similar type so that every signal sent may be
recorded for future reference. Such recorder may be worked by a separate battery
or on a shunt circuit from the source which actuates the lamp.
I add to the apparatus such switches and keys as may be necessary for turning the
lamp on and off or putting the recording instrument in and out of action.
Dated this Twenty-second day of May 1889.

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Signal Lamps and Appliances connected
therewith.
FREDERICK LAWRENCE RAWSON of 60 Hammersmith Road in the county of
Middlesex Electrical Engineer and WILLIAM STEPNEY RAWSON of 68 Cornwall
Gardens London in the County of Middlesex Electrician, 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:-
.
The object of the invention is to produce an improved signal lantern for marine
and other purposes and it is especially applicable to lanterns in which an electric
incandescent lamp is used as the source of light and where the signals are conveyed
by means of electric impulses.
The lamp is mounted in a lantern which can be suspended at the mast-head.or
yard-arin or other exposed position & which is provided with a circular dioptric lens
or other known method of producing horizontal beams of light or the lens may be
replaced by a simple cylinder of strong glass as transparent as possible. In one
form of apparatus surrounding the lamp are a number of blinds or shutters which
revolve on vertical pins & are actuated simultaneously by a wheel or similar
mechanism which. by its motion engages with each shutter & causes them to turn
through an angle of about 90 degrees.
The inotion of this wheel is produced by the movement of the armature of an
electro-magnet. The passage of a current through the electro magnet causes the
armature to move & carry with it the wheel against the force of a spring. By this
action the shutters may be opened or shut. On the cessation of the current the
spring carries the wheel back to its original position & the shutters are shut or
opened by the wheel.
By opening & closing the shutters flashes of light are sent-round in all directions
& so can be used for signalling purposes.
In another form of our apparatus the shutters are replaced by a single cylinder
shutter moving vertically by the movement of the core of a hollow magnet or
solenoid.
In order to avoid the incandescent lamp being always run at its full incandescence
when its light is cut off by the closed shutters or cylinders or other form of obscuring
apparatus of the shutter type we put the electro magnet in series with the lamp & we
arrange the mechanism of the shutters (or other apparatus) so that when no current
is passing through the magnet, the spring opens the shutters or withdraws the
obscuring medium but on the passage of a current the attraction of the armature
causes the shutters to close & the light to be obscured & at the same time the lamp is
rendered duller by the resistance of the magnet in circuit with it. If desired a
special resistance can be put in by the action of the mechanism either separately or
together with the electro magnet.
By this arrangement the heating inside the lantern which is of a closed form is
greatly reduced & the life of the lamp increased. The key which is necessary for
cutting the electro magnet in and out of circuit should be so constructed that the
lamp circuit should be made before the magnet circuit is broken and vice versa.
By this arrangement the sparking during signalling is very slight.
Together with this key we may combine a recording instrument of the Morse or
similar type by which the short and long signals may be reproduced by the well
known dot and dashes of the Morse alphabet. And in the same way as in
telegraphic messages perforated slips are prepared by hand & used afterwards to send
messages by the well known Wheatstone instrument so with such an arrangement as
ours perforated slips may be arranged for actuating the contact making apparatus
of the key & so the signals may be sent.
The advantage of such a system working automatically is that the speed of
signalling may be definitely decided by clockwork & not be left to the operator

page_text: who may work faster than the signals can be "picked up" by eye thereby causing
serious mistakes in many cases.
When a Morse recording apparatus is used in conjunction with the lamp both the
printing & clock magnets are preferably worked by a separate battery but when the
automatic switch (as described below) is used we may work either or both magnets in
shunt upon the main current with proper resistances interposed.
As it is destructive to the lamp to leave it running uselessly when not signalling
we employ a switch of particular construction by which the movement of the
operator's hand previous to pressing the key for signalling completes the main
circuit through the lamp & magnet & when the hand is removed the circuit is
automatically broken by the action of a spring or equivalent device.
With reference to the accompanying drawings Fig. 1 gives a vertical section &
Fig. 2 a horizontal cross section of one type of lantern showing respectively the form
of the shutters & the manner in which the wheel engages with the shutters.
The cover R of the lantern noves on the hinge Z & in order to complete the
connections to the lamp it is only necessary to screw down the fly nuts A A thereby
pressing the springs V, V against the plates X, X. 'The wires from the terminals L, Ď
fig. 4 are connected to these plates. In order to facilitate repairs in case any accident
happens to a shutter we inake the whole shutter frame (which consists of upper &
lower rings a, b joined by bars see Fig. 1) detachable together with the sprocket
wheel which is prevented from falling by the flanges on b. The pivots of the shutters
move in screwed bearings above (I fig. 1) so that they can be separately taken out
and adjusted. The sprocket wheel P engages with the pin J to which the armature O
is attached & the fly nut K keeps it in its place. The fly nut can be reached by the
hand from inside & thus the shutters & sprocket wheel can be detached together bodily
without disengaging the latter from each separate shutter.
The magnet is made double & wound so as to give opposite poles at similar ends.
The two bobbins may be put in series or parallel according to the resistance we
require to interpose & the current we have at our disposal. As a rule they will
be inore conveniently in series. The springs H, H are attached to the armature
so that when the latter is attracted the springs are extended & when the current
is broken the springs bring the armature back to its original position. The
stops N. N are arranged so as to limit the movement.
For a lamp of 100 candle power & 80 volts their resistance in series will be
about 2 ohms. &.they will absorb about 8 volts. They are protected from damage by
a stout tube d surrounding them.
There are three terminals insulated from each other & from the framing which
carries the inagnets. In Fig. 4 we show the electrical connections of the magnet &
lamp circuit to these terminals.
When the dynamo terininals are joined to M. T & D the current passes through the
lamp & magnet in series when they are joined to L & D it passes through the lamp
only.
The position of the sprocket wheel is so arranged that in the former case the
shutters are closed & in the latter they are open.
It will be seen that to prevent breaking the main circuit it is necessary to make
contact at L before breaking at M-T & vice versa.
Fig. 5 shews another form of apparatus which may be employed with a similar
result. Instead of revolving shutters we use a light cylinder of opaque material
(moving preferably inside the glass envelope surrounding the lamp). This cylinder
is attached by suitable arms P to the core O of the hollow magnet C. Each of
these arms has attached to it a lug Q & through this lug slides a rod R carrying
at its lower end a spring which comes into action just before the shutter has dropped
to its lowest position, acting therefore as a buffer & quickening the return when the
current passes through the solenoid. Suitable buffers N, N, are provided of rubber
or similar substance to break the force of impact both upwards & downwards.
The electrical. connections (see Fig. 6) are similar to those in the previously described
form!

page_text: Figs. 7 & 8 9 & 10 show different forms of automatic switch in which we combine
the flashing key & an automatic switch for breaking circuit when the operator's hand
is removed.
Figs. 7 & 8 shows a form in which the clock of the Morse recorder is started &
stopped at the same moment as the main current is inade & broken to the lantern. In
this case the clock magnet M-C is actuated from the same source as the lamp, the
resistance of the magnet being suitably proportioned to the E.M.F. used with the
lamp or an external resistance r being introduced to reduce the current.
The printing magnet M-P is preferably actuated by a separate battery S which is
attached to the terminals M-P & M-M through the printing magnet.
Fig. 7 gives the diagram of the connections of this form of our automatic switch.
Figs. 9 & 10 shew a simpler form of the switch in which the clock magnet of the
Morse recorder is not actuated by the switch but has to be started & stopped
independently. In both Figs. 7 & 9 it will be seen that a dynamo terminal is
connected to the terminal marked D, the terminal L is joined to the terminal L, in the
lantern & the terminal M-T to the terminal M₁-T, in the lantern. The automatic
make & break of the main circuit is effected by the movement of the handle H which
must be depressed before a signal can be sent & by this movement contact is made
at C which completes the current through the magnet & lamp. As soon as the hand
is removed the spring f pulls the handle up & contact is broken at C.
In figs. 8 and 10 we show. how the contacts are made by means of the platinum
points m-t, m-p & 1.rubbing against, vertical springs k, k & the height of these
springs is so adjusted that during the movement of the arrn of the switch contact is
momentarily made simultaneously at 1 & m-t but at the beginning of the stroke
only m-t is making contact & at the end only is in contact. Thus the main circuit
from the dynamo is never broken as long as the hand depresses H sufficiently to
make contact at C.
In fig. 9 the switch S-W turns the current of the battery S off & on as required
for the clock magnet of the recorder.
We are aware that a patent No. 17770 of 1888 has been granted in which pivotted
shutters have been used for flashing signals by electro magnetic apparatus & we do
not lay claim to this portion of the apparatus but what we claim as new is as
follows
I. In an electric flash signalling lantern in which signals are produced by the move-
ment of one or more shutters due to electro magnetic action the arrangement of
the lamp & magnet circuits whereby the intensity of the lamp is diminished when the
lamp is obscured substantially as described.
II. The combination of a flash signalling lantern in which the flashes are produced
by making or breaking an electric contact with a recording apparatus whereby the
signals are automatically recorded.
III. The combination of an electric flash signalling lantern having an arrangement
of circuits as described with a key for cutting the magnet in & out of circuit, with or
without recording apparatus substantially as described.
IV. The combination of an electric flash signalling lantern with the arrangement of
circuits as described with an automatic signalling switch, with or without recording
apparatus substantially as described.
V. In a flash signalling lantern the arrangement of parts substantially as described
& as shewn in Figs. I, II, III & V.
VI. An automatic electric signalling switch substantially as described & as shewn in
Figs. VII VIII IX & X.