An Improved Method of Making Electrical Contacts between Parts of Electrical Apparatus.
Year: 1892

page_text: Date of Application, 27th Aug., 1892
Complete Specification Left, 23rd May, 1893-Accepted, 26th Aug., 1893
PROVISIONAL
SPECIFICATION
An Improved Method of Making Electrical Contacts between Parts
of Electrical Apparatus.
We WILLIAM ERNEST GRAY and WILLIAM ARTHUR PRICE, both of
Silvertown in the County of Essex, Electricians, do hereby declare the nature of
this invention to be as follows:-
The chief object of this invention is to avoid the difficulties that have been
encountered in the making and breaking of contacts in the transmission automatically
of telegraph messages. Our invention also applies, however, to the making of
electrical contacts, wherever intermittent currents are to be transmitted.
When using a perforated strip for the automatic transmission of messages, as in
the Wheatstone system, we cause a fine jet or jets of mercury issuing from a
reservoir connected with one pole of a battery, to fall upon the strip, and thereby
to make electric contact with the wheel which traverses the strip past the jet or
jets, and is itself connected with the other pole of the battery.
In applying the invention to a receiving instrument, we interpose between the
stream or streams of mercury, and a metallic surface connected with one pole of
the battery, a screen carried by a swinging arm, which is operated by a relay, or
forms a part therewith. When the screen is withdrawn from under the jet, metallic
contact will be established, and when moved to intercept the stream, the current
will be broken. When positive and negative currents are used, the swinging arm
may be moved to the right or left at pleasure, and the same movement repeated as
often as desired to accord with the signal transmitted.
It will be obvious that other arrangements may be adopted to intercept the
mercurial jet, and thus to break, at desired intervals, metallic contact, but the
means which we have described will in general suffice to obtain a good result.
Dated thin 7th dove of taunt 1000
NEWTON & SON,
Agents for the Applicants.
COMPLETE SPECIFICATION.
An Improved Method of Making Electrical Contacts between Parts
of Electrical Apparatus.
We, WILLIAM ERNEST GRAY and WILLIAM ARTHUR PRICE, both of
Silvertown in the County of Essex, 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 :-
The chief object of this invention is to avoid the difficulties that have been
encountered in the making and breaking of contacts, in the transmission auto-
matically of telegraph messages.
.
Our invention also applies, however, to the making of electrical contacts wherever
intermittent currents are to be transmitted.
The disadvantages attendant on the circuit breakers and makers in common use,
are of two kinds; 1st, the cost of their manufacture, and 2nd, the difficulty of
keeping the contact surfaces clean. To avoid these disadvantages, we propose to
employ a jet or jets of mercury for making metallic contact, employing a strip of
pierced paper for making or breaking the circuit.
In the accompanying drawings, we have shewn our invention as applied to an
automatic transmitting telegraphic instrument attached to a cable in which it is
usual to employ reverse currents, and to put the cable to earth between every
signal transmitted,

page_text: Fig. 1 is a front view of the transmitting instrument, a portion of the case being
broken away, to shew the construction of the parts contained therein for making
and breaking electric contact.
Fig. 2 is a plan view of the complete apparatus, the cover of the case being
removed; and
Fig. 3 is a partial end elevation, the end of the case being broken away to shew
the interior.
A A is a back-board standing up from a base piece, and carrying, on one side,
a closed case B, which is fitted with jet pipes C C', in front of a segment-shaped
block D of contact plates made fast to the back-board. The pipes CC¹ are made
preferably of steel, and are insulated from the rest of the apparatus, and these
pipes are designed to discharge three jets of mercury at different levels on to three
insulated steel plates, 1, 2, 3, overlying one another, and composing the block D,
the moment and duration of contact for each jet being determined by the traverse
of a strip of pierced paper over the block, such paper being prepared in the
manner commonly employed in automatic telegraphy.
To ensure the proper action of the instrument, the pipe C is made adjustable
axially, so that its jet may act only when the jets of the pipe C¹ are interrupted by
the travelling strip.
E is the strip of pierced paper, which is led over the face of the segment
block D from a drum, not shown in the drawing.
Entering through a slot at one end of the case B, it passes under a guide
roller F, thence over the metal contact plates 1, 2, and 3, of the block D (which
are separated from one another by ebonite plates or other insulating material), and
under a second guide roller F, and out through a slot in the opposite end of the
case, where it takes a twist at right angles, and is laid over a vertical drawing-off
wheel G, driven by means of an electro-motor situate on the opposite side of the
back-board to that which carries the case B.
In place of plain rollers, we may use pinned rollers for guiding the strip of
paper, the pins being gauged to fit the holes in the middle or second line of the
pierced strip. The jet pipes C C connect by means of flexible tubes with an
elevated reservoir H, shown in Fig. 4, and serving to contain a supply of mercury.
This reservoir is connected with an Archimedian pump 1, which is designed to
receive the overflow mercury from the jet pipes supplied thereto from the
reservoir H, and raise the overflow mercury again to the reservoir.
The pipes CC discharge through jet holes the mercury which they receive,
against the segment block D, partially covered by the pierced paper E, for the
purpose of making metallic electric contact, as will be hereafter described, and the
mercury, after striking against the block, falls to the bottom of the case B, whence
it escapes, by an opening in the bottom through the tube K, to the well or cup-
shaped base of the Archimedian pump 1. This pump I is mounted in suitable
bearings, and is fitted with a worm wheel I' in gear with a worm on a shaft L, to
which is fitted the armature of an electro-motor L', for giving rotary motion to
the pump 1, and thereby raising the mercury, as it is discharged from the trans-
mitting instrument, to the reservoir H.
Referring now, again to Figs. 1 and 2, the drawing-off wheel G, it will be seen,
is mounted on an axle G', which has its bearing in the back-board A, and projecting
through the same, carries, at its other end, a worm wheel G2. Gearing into this
wheel G2, is the worni of a shaft M, mounted in bearings bolted to the back-
board A.
This shaft M serves to carry the armature of an electro motor N, and it is also
fitted with a flanged disc of copper M1, which, rotating between the poles of an
electro magnet O, serves, when that electro magnet is excited, to retard the rotation
of the shaft M, and consequently control the rotation of the wheel G and the
speed of traverse of the strip of pierced paper over the metal contact surfaces of
the block D, the paper being held in contact with its drawing-off wheel G by
means of a pressure roller G.

page_text: Fig. 5 shows in full size a portion of the strip of paper used for making and
breaking contact between the mercurial jets and the metallic plates 1, 2, and 3,
composing the block D.
These plates (see Fig. 1, and also the diagram Fig. 6) are each provided with a
terminal; that of the plate is connected with the positive pole of a battery P,
the negative pole of which connects with earth.
The terminal of the plate 2 connects with the negative pole of a battery Q, the
positive pole of which connects with earth; the terminal of the plate 3 connects
with earth.
The jet pipes C & C¹ are electrically connected with the cable R (Fig. 6), or, it
may be, with a line wire; thus, when either of the jets is permitted to strike the
plate to which it is opposed, an electric circuit will be completed, and either a
current from the positive pole of the battery P will pass to the cable, or a reverse
current will pass through the cable to the negative pole of the battery Q; or a
current will pass from the cable to earth, to clear the cable.
The electro-motor N connects with the battery S, which also serves to excite
the electro magnet O, by which, through the flanged copper disc M', the action of
the electro motor is controlled. By the insertion of a rheostat T in the circuit
of the electro-magnet O, the speed of the motor N may be regulated. The
battery S serves also, as indicated by the diagram Fig. 6, to energize the electro
motor L' for driving the Archimedian pump.
In order to start the instrument, it is only necessary, when the paper strip is
inserted, and the motors are energized, to turn on the taps which control the flow
of mercury, and the transmission of the message will proceed automatically.
When the message has been transferred, and the motors are arrested, the taps
should be turned off, to suspend the flow of the mercury.
It will be obvious, that where no necessity exists for using reverse currents, one
jet will suffice to make the requisite electric contact, and the paper will, in that
case, be pierced with one row of holes only for transmitting the telegraphic
message.
Although we have described our invention as applied only to a transmitting
instrument, it will be obvious that it is equally applicable to making and breaking
contact in receiving instruments.
To render this more clear, we append a diagram, Fig. 7, which will explain the
mode of adapting the mercurial contact to a receiving instrument.
In this figure,
H is the mercury reservoir; C* a jet pipe for discharging a stream of mercury
across the path of a contact piece D, into a receiver 1, whence it is raised, and
The
discharged, as above explained, into the reservoir, ready for repeated use.
reservoir His electrically connected with a local battery P*. R is the cable
leading from the transmitting instrument to a relay R', which communicates by a
wire R with earth. The currents transmitted to this relay actuate an armature R³,
the free end of which carries the contact piece D*, raises that contact piece up to
the mercury jet, and allows the current derived from the local battery P✶ to flow
through the armature R³, and, by a wire R', to, say, a Morse sounder R. This
sounder connects by a wire R' to the local battery P*, and draws to it an armature
for producing the signalling sound at every passage of the electric current through
the sounder.
Having now particularly described and ascertained the nature of our inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
The means above described for making electrical contacts in telegraphic and
other electrical apparatus.