IMPROVEMENTS IN ELECTRO-MAGNETIC TELEGRAPHIC APPARATUS
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by Charles Wheatstone and John
Matthias Augustus Stroh at the Office of the Commissioners of
Patents, with their Petition, on the 18th August 1871.
We, CHARLES WHEATSTONE, of 19, Park Crescent, Regent's Park,
Knight, and JOHN MATTHIAS AUGUSTUS STROH, of 29, Tolmer's Square,
Hampstead Road, Mechanician, both in the County of Middlesex, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
ELECTRO-MAGNETIC TELEGRAPHIC APPARATUS," to be as follows:-
The first part of our Invention relates to improvements in the
construction of step-by-step telegraphs, the object of which is to
enable the hand or indicator of a large dial, or in some cases the dial
itself, to be moved rapidly with the same certainty as the indicators of
the small dials usually employed. To obtain this object we transfer the
propelment of the index or pointer to the action of maintaining power,
limiting the work performed by the transmitted currents to the
controlling of the scape wheel, and introducing a special arrangement
obviating the retarding effect due to the weight of the index hand, as
will be more clearly shewn by the accompanying Drawings and descrip-
tions thereof.

page_text: On an axis a, Fig. 1, driven by the maintaining power of clockwork
gearing with is firmly fixed an index hand or pointer P and an arm Z.
At the extremity of this arm a pinion d, centred at c, and gearing with
the stationary wheel D, shewn in segment only, carries two equal arms
e, c. Mounted loosely on the axis a is a scapo wheel A, to which one
end of a light spiral spring S is attached, the other end being fixed to
the axis a, so that the scape wheel remaining stationary and the axis a
revolving the spiral spring S would be wound up, and conversely the
axis a remaining stationary and the scape wheel free to move the spiral
spring in unwinding itself would tend to propel the scape wheel forward.
To the centre of the scape wheel A is fixed the piece f, carrying at its
extremity a stop n, which when the scapo wheel is at rest is met by
the end of one of the arms e, e, attached to the pinion d, and thereby the
revolution of the axis a and consequently the pointer P prevented. The
control of the scape wheel is effected by the pallets B, B, to which an
oscillatory motion is communicated by any suitable electro-magnetic
arrangement such as E, E, in such a way as to allow the scape wheel to
advance with a step-by-step motion one half tooth for every movement of
the pallets. It follows from this arrangement that with every movement
of the pallets B, B, the scape wheel A, driven by the spiral spring 8, will
advance; and this forward movement of the scape wheel will by, with-
drawing the stop n release the arm e; and allow the maintaining power
gearing with the pinion x to propel the axis a, the pointer P, and the
arm Z, and thereby to wind up the spiral spring S. The pinion d
carrying the arms e, e, at the extremity of the arm Z, and gearing with
the stationary wheel D, will thus be caused to rotate after the manner
of the sun-and-planet movement until the scape wheel coming to rest
locks the whole again by presenting the stop » to either of the arms e, e.`
The number of teeth of pinion d, the stationary wheel D, and scape
wheel A aro so arranged that for every half tooth of the scape wheel
liberated by the pallets B, B, the arms e, e, attached to pinion d make
one half revolution. It also follows that the pointer P will be allowed.
to advance one space on the dial for every half tooth of the scape wheel
so liberated; and thus, while the movements of the pointer are
independent of the step-by-step motion of the scape wheel, the intter
completely controls its starting and stopping. To prevent the recoil
of the index hand when suddenly arrested by one of the arms e.

page_text: impinging on the stop n, a small catch p (see Fig. 2) is mounted loosely
on the axis a, its motion being limited by the stop r and the stop ».
The descent of the end of either of the arms e, e, will force the bevilled
head of the catch p back against the spring y, which after the descent of
the arm upon the stop n restores the catch to its former position, so
that the end of the arm e is held fast between the stop n and the catch p
until the revolution of the scape wheel carrying with it the piecef and
catch p again releases the arm e. From the above arrangement it will
be perceived that the starting and stopping of the scape wheel is not
affected by the inertia or momentum of the heavy index hand which is
enable to start and come to rest after the scape wheel.
Another method of effecting this purpose is shewn in Fig. 3. To the
pointer P fitting loosely on the axis a is attached a counterbalance H,
provided at one extremity with a notch, through which a pin K fixed to
the circumference of the scape wheel passes. The picce H carries a
delicate spring J, so bent that when at rest the pin K is held by this
spring in the centre of this notch. For the purpose of rostoring tho
index hand when out of adjustment to the + or zero point on the dial,
the axis 6 of the pallets B, B, centres in the shorter arm of a bent rigid
lever F, F, (Fig. 3) centred at C, and held in normal position by a spring.
Any pressure at I will cause an upward movement of the shorten arm
F, F, thereby lifting the pallets B, B, out of gear with the teeth of the
scape wheel. Thus freed the scape wheel propelled by the maintaining
power will fly round, carrying with it the pointer P and counterbalance
H, until the pin or projection on the extremity of H meets the pin L
projected forward by the pressure at I. Or in case of the arrangement
shewn in Fig. 1, the scape wheel will revolve until either of the arms
e, e, impinge upon the stop n, and in both cases the index hand points to
The removal of the pressure at I allows the pallets to re-engage
with the teeth of the scape wheel. In place of the index hand pointing
to letters or signs engraved upon a fixed dial, a fugitive dial Q, Fig. 4,
of any desired dimensions passing beneath a fixed screen S (having a
perforation permitting only one letter engraved on the fugitive dial to
appear) may be mounted upon the axis a. Again in place of letters on
the dial of the indicator there may be signs or sentences, the transmitting
instrument having on its dial corresponding signs or sentences.
zero.
This modification is of special use in the construction of signal
apparatus such as employed on shipboard and elsewhere.

page_text: The second part of our Invention relates to improvements in type-
printing telegraphs. The first of them consists in the application of the
means previously described for moving a large hand with steadiness and
rapidity to regulating the motion of the type wheel. The second to the
means employed by which the stamping of a letter on the paper strip is
effected automatically immediately after the cessation of the last of the
electric currents necessary to bring the type wheel to the requisite
position; and the third to the peculiar contrivance for regularly
supplying ink to the type wheel.
Mounted on the axis A, Fig. 5, in place of the pointer or index hand
is a wheel R gearing with another wheel Y fixed firmly on the arbor
of the type wheel. By means of these wheels the maintaining power
moving the type wheel is controlled by the pallets B, B, as described
in the first part of our Invention. Also mounted on the arbor of the
type wheel is a saw-toothed wheel Z, and in play with the teeth of this
wheel is a pin m fixed into the extremity of the arm E, this arm being
centred at e, and continuing in a light rigid bar E¹ bearing on a friction
wheel. During the rotation of the wheel Z the pin m cannot fall to
rest between any of the teeth, and the arm E is therefore kept up..
The pin m presses in its upward motion against a segmental arm d
centred in C, in which also is contred the arm n bearing against a pin
in the segmental arm, and sustains these two arms, keeping the releasing
arm L, centred at i, free from pin 1 at the end of the arm n, and allowing
a check picce of the releasing arm to rest upon pin 2 in the arm y,
which is centred half way up the arm n, and kept in position by a
spiral spring S. A continuation of the arm n has pivoted at its
extremity a light bar bearing upon friction wheels. When the rotation
of the wheel Z ceases, the pin m and the arms & and n fall, and before
the end of the releasing arm L can engage with pin 1 the check
picce is liberated from its position of rest on pin 2, and the arm L falls.
A transverse groove in the arbor of the arm L retains the end of a piece
j, jutting from the axle of a pinion p, gearing with a wheel N fixed on
the arbor of a second wheel M having widely spaced teeth, which wo
call the stamping wheel. With a pinion W also on the arbor of the
stamping wheel a maintaining power separate and different from that
imparting motion to the type wheel is in gearing. The fall of the arm L

page_text: .
liberates the piece ;, and this piece in making one revolution before it
again engages in the groove of the arbor of the arm L. permits the
stamping wheel to be carried forward one tooth, by the maintaining
power in gearing with it. The tooth of the stamping wheel coming
in contact with the touch piece h, Fig. 6, causes the printing hammer z
to be lifted against the rim of the type wheel T. Consequently the
letter immediately presented to the face of the printing hammer is
printed on the paper slip, which interves between the type wheel and the
hammer. The action on the printing hammer is direct, but in the case
of the arm La series of levers r, r, r, Fig. 5, are brought into play.
After the printing of a letter the paper slip is carried forward by a
milled wheel W fixed to the arbor of the stamping wheel, and which
bears on a roller G pressed against the milled wheel by a spring, the
paper slip passing between the milled wheel and the roller. The ink is
supplied to the type wheel by means of a brush inking wheel I, Fig. 6,
which rests on and is caused to revolve by the rim of the type wheel.
The ink is supplied to the inking wheel by means of the arm K, which
is loosely attached to the arbor of a wheel in gear with the train of the
maintaining power moving the type wheel. The arm is carried up by
means of a pin i, and having at the lowest point of its revolution dipped
into a semicircular ink vessel it falls in its revolution into contact with
the inking wheel, imparting to it its charge of ink. The type wheel is
adjusted to zero by the arrangement described for adjusting the index
hand or pointer of the first part of our Invention.
The third part of our Invention refers to a switch or current director,
consisting of a series of finger studs or keys, so disposed that on the
pressure of any one key the current is diverted into a new channel, and
at the same time diverted from the previous one.

page_text: voltaic battery is attached, its other pole being connected with the return
or earth wire. D, E, F, G, represent the ends of the wires to which the
currents from R can be communicated at will; they are attached to
the springs or pieces of metal C, C, C, C, Fig. 13, insulated from the rest
of the instrument by some non-conducting material B, B; upon the
depression of a stud the end of it will touch a spring, and make a metallic
contact therewith. The stud will remain thus in contact until another
stud is depressed, and it will be seen that in this arrangement, which is
capable of extension to any number of keys or studs, only one can be
depressed and one contact made at the same time. The mechanism on
which the peculiarity of this switch depends resembles that employed
in the magnetic communicator of an alphabetical telegraph, described as
the improvement in the Specification of a Patent granted to one of
us, dated 2nd June 1858, No. 1241; but we now claim it when applied
to an instrument for a very different purpose, namely, that of directing
currents from one line to another.
Our fourth improvement consists in the construction of a magneto-
electric apparatus suited for the purpose of producing in an effective
manner the currents necessary to ring electro-magnetic bells.
MAGNETO-ELECTRIC MOTORS FOR DOMESTIC AND OTHER BELLS.
Attached by iron connecting bars to the poles of the compound
permanent magnets M, Fig. 7, aro the soft iron cores of two bobbins
B, B', upon which is wound a quantity of insulated wire, the two ends
of the wire being in connection the one with the return wire or earth,
and the other with the wire attached to the coils of the distant bell.
The armature hinged on the brass slab X, X, is raised from both the soft
iron cores of the bobbins simultaneously when the pull is depressed by
three cams C, O, C, arranged in a circle, and playing upon a friction
roller R mounted in the face of the armature. The cams work with the
forward motion of the arbor A of the pull or bell handle, through
the click and ratchet C and D, on the depression of which therefore
the cams raise the armature, and permit it to fall three several times;
but on the return of the handle the click runs on the ratchet, and the
armature remains unmoved. Consequently six reversed currents aro
despatched into the wire connected with the distant bell. a and b,
Fig. 8, are two springs, one of which is in metallic contact with a piece
of brass insulated from the body of the instrument. When the pull is in

page_text: its position of rest, as shewn in the Drawing, the circuit is interrupted;
but when the pull is depressed both springs press on the insulated brass
pieces, and the currents generated in the coils pass into line. By means
of this temporary completion of the circuit the currents are compelled
to go into their proper channel and thus avoid ringing other bells in the
same system.
Figs. 9 and 10, shew a modification of the form of magneto-electric
pull, the motion being horizontal instead of rotating. Attached to the
poles of the permanent horse-shoe magnets M, M, Figs. 9 and 10, aro
the soft iron cores of two bobbins B, B', upon which is wound a quantity
of insulated wire, the two ends of the wire being in connection, the one
with the spring d, and the other with the wire attached to the coils of
the distant bell. The armature attached to the hinged piece x is raised
from both the soft iron cores and bobbins simultaneously when the pull
is drawn out by the cams C, C, O, arranged horizontally and playing
upon a friction roller R mounted at the end of the piece x, x. The
cams work with the horizontal motion of the cam piece D, to which the
handle H is attached, on the withdrawal of which the cams raise
the armature, and permit it to fall several times, and consequently
several reversed currents are despatched into the wire connected with
the bell. When the pull is in its position of rest, as shewn in the
Drawing, the circuit is interrupted, but when the pull is withdrawn the
spring d presses on the guide c, which keeps the piece D in its proper
position, and the currènts generated pass into the line.
Fig. 11 represents the general disposition of a circuit including, 1st,
the magneto-electro bell pull; 2nd, the finger key switch or current
director; and 3rd, the bell with its assisted tell tales.