IMPROVE- MENTS IN PRINTING TELEGRAPHS
Year: 1884

page_text: I, WILLIAM PHILLIPS THOMPSON of the Agency for Foreign Patent Solicitors
G, Lord Street, Liverpool, in the county of Lancaster, Fellow of the Institute of
Patent Agents do hereby declare the nature of the said invention for "IMPROVE-
MENTS IN PRINTING TELEGRAPHS and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
22
The invention relates to certain improvements in the construction of devices for
determining from which particular one of two type-wheels in a printing telegraph
receiving instrument an impression shall be taken.
The object of the invention is to so organize the apparatus that the desired
impressions may be taken from either of the type-wheels at a distant station by
means of electric currents transmitted over a single main line conductor, without
the aid of complicated mechanism.
The invention consists in constructing an instrument with a double electro-
magnet for controlling the movements of an escapement device and two additional
independent electro-magnets which are respectively adapted to actuate a pressi
lever, and to determine the position of a printing platen of peculiar construction..
This platen is virtually a double one, consisting of two single platens united at an
angle with each other and situated in different planes, the one being located in the
plane of one of two parallel type-wheels and the other platen in. the plane of
the other type-wheel. When the armature-lever which is employed for determining
the position of the double platen, is remote from the poles of its electro-magnet,
one of the platen faces will be presented to the corresponding type-wheel and, if
the press-lever be then actuated, it will cause an impression to be taken from that
type-wheel in the usual manner, the other platen face meantime remaining at such
an angle with reference to its type-wheel that no impression will be taken
therefrom.
When on the contrary the armature is attracted to the poles of its magnet, the
double platen will be turned, by means of suitable intervening mechanism, so that
the second platen-face will be presented to its type-wheel, and the first platen will
be at such an angle that no impression will be taken from the first type-wheel.
'

page_text: It will appear from the foregoing description that it is necessary to provide
currents of alternating polarity for actuating the escapement mechanism for
controlling the rotation of the type-wheel and currents having a strength somewhat
greater for actuating the press-lever, or if preferred the printing magnet may be
constructed to respond to a prolonged current of the same strength as the
alternating currents. In either event, the current employed for this purpose
should not be of sufficient strength to actuate the armature of the platen-
controlling magnet, but this armature is so constructed or adjusted that it will
respond only to currents of increased strength, such currents being also adapted to
actuate the press-lever. By means of currents of this class impressions may be
taken from the second type-wheel.
In the accompanying drawings, which illustrates the invention, figure 1 is an
.elevation showing the organization of the apparatus, and figure w is a perspective
view illustrating the construction of the platen.
Referring to the figure, A1 and A2 represent two type-wheels of usual
construction placed side-by-side upon a shaft a, the periphery of the type-
wheel A 1, for instance, being engraved with type representing numerals while
that of the type-wheel A 2 is engraved with letters. Carried upon the shaft a
is a scape-wheel B normally tending, through the stress of a spring or weight, to
revolve continuously in the direction indicated by the arrow. An anchor-
escapement C of ordinary construction regulates or controls the movements of
the wheel B by engaging teeth alternately upon opposite sides of the same.
necessary vibrations of the escapement pallets are occasioned by an electro-magnet
M M 1 acting, under the influence of alternating electric currents traversing its
coils, to impel a polarized armature, D to and fro, in a manner well understood.
The type-wheels are thus simultaneously caused to advance step-by-step and to
successively present the individual type upon their peripheries to a combined or
double printing platen E.
The
The double platen Ẹ consists of two single platens e 1 and e 2 rigidly secured to
éach other and respectively designed to take impressions from the type-wheels A 1
and A 2. The combined platen thus formed is pivoted in a bracket upon the
armature-lever F of a press-lever P¹. The two parts of the same are however
united at an angle as best seen in figure 2, so that while the printing face of one
of the platens, e 2 for instance, is presented to its type-wheel A 2, the face of
the other platen will be in such a position as not to come in contact with its
type-wheel A 1 during the upward movement of the press-lever F, and vice-versa.
For the purpose of controlling the position of the double platen E, a special
electro-magnet R is provided. The armature-lever H of this magnet is coupled by
means of a pivoted link J, with an arm e 3 upon the platen E. When the armature-
lever is away from the poles of its electro-magnet R the platen will be caused to
assume the position shown in full lines in the drawing, with the part e 2 facing the
type-wheel A 2. When however a current of sufficient strength to attract its
armature h to its poles, traverses the coils of the electro-magnet R, the armature-
lever and platen will be moved into the position shown in dotted lines figure 1, the
part e1 being in the position to cause impressions to be taken from the other
type-wheel A.L
The printing magnet P may be constructed either to respond to currents of
greater strength than those employed for actuating the escapement C, or to
a simple prolongation of one of the alternating pulsations, while the armature of
the electro-magnet R will respond only to currents of a strength'still greater than
those required to actuate the press-lever. The latter, however will also respond
likewise to the strongest currents. It will thus be seen that when it is desired to
print characters from the type-wheel A 2, the type-wheels should be revolved until
the desired character is opposite the platen when a current of the character required
to actuate the lever P¹ should be transmitted through the coils of the magnet P.
If however an impression should be desired from the type-wheel A1 after it has
*been arrested in the proper position, a current of the strength requisite to actuato

page_text: the lever H of the electro-magnet R should be transmitted through its coils.
The platen will be caused to assume its second position, and the press-lever will be
actuated, thereby.
The invention has been shown and described as including the several electro-
magnets in a single conductor, though it is evident that a second conductor might
if preferred be employed for the electro-magnet R.
In order to insure the platen being in position to print from the type-wheel A 1,
under the influence of a strong current, before the press-lever has carried the same
into too close proximity to its type-wheel, it is preferred to so construct the
electro-magnet R that it will acquire the full degree of magnetization of which it
is susceptible under the influence of a current of given strength, somewhat more
quickly than will the electro-magnet P. In this manner the armature-lever H may
be caused to assume its forward position under the influence of a current of the
strength required to actuate it, before the press-lever responds to the action of the
same current.
Having thus described the nature of this invention and the manner in which it
is to be performed, as communicated to me by my foreign correspondent, I would
have it understood that I Claim:-
1. The combination, substantially as herein before set forth, of two type-wheels
revolving in parallel planes, two platen-faces, rigidly united with each other, but
situated in different planes, and supported upon a common axis, and an electro-
magnet serving, when vitalized, to cause one of said platen-faces to confront one
type-wheel and when not vitalized to permit the other platen to confront the other
type-wheel.
2. The combination, substantially as herein before set forth, of two type-wheels,
means substantially such as. described, for imparting an intermittent advance
movement to said type-wheels, a printing magnet, its armature and armature-lever,
two platen-faces united with each other, but situated in different planes, and an
electro-magnet acting when vitalized to present one of said platen-faces to one type-
wheel and when not vitalized to present the other platen-face to the other
type-wheel.
3. The combination, substantially as hereinbefore set forth, of a type-wheel
axis, two type-wheels fixed thereupon, and revolving in parallel planes, two platen-
faces situated respectively in the planes of said type-wheels, and supported upon
an independent axis parallel with said type-wheel axis, an electro-magnet, its
armature and armature-lever, and a link connecting said lever with said platen-
faces whereby the latter may be turned upon their common axis by the to-and-fro
movements of said lever.
4. The combination, substantially as hereinbefore set forth, of a type-wheel
axis, two type-wheels' fixed thereupon and revolving in parallel planes, a printing
magnet, its armature and armature-lever, two platen-faces supported upon said
armature-lever upon a common axis parallel to said type-wheel axis, and an
independent electro-magnet for controlling the angular position of said platen-faces.
Dated this 27th day of February 1884.
W. P. THOMPSON,
6, Lord Street, Liverpool.